NZ616465B2 - Combination of anti-clusterin oligonucleotide with androgen receptor antagonist for the treatment of prostate cancer - Google Patents

Abstract

Discloses use of i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure as disclosed in the complete specification, or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for treating a mammalian subject afflicted with prostate cancer. Also discloses an oligonucleotide which reduces clusterin expression and an androgen receptor antagonist, in the manufacture of a medicament for the treatment of a mammalian subject afflicted with androgen-independent prostate cancer. ted with prostate cancer. Also discloses an oligonucleotide which reduces clusterin expression and an androgen receptor antagonist, in the manufacture of a medicament for the treatment of a mammalian subject afflicted with androgen-independent prostate cancer.

Description

COMBINATION OF ANTI—CLUSTERIN OLIGONUCLEOTIDE WITH ANDROGEN RECEPTOR ANTAGONIST FOR THE TREATMENT OF PROSTATE CANCER This application claims priority of U.S. ional Application Nos. 61/452,583, filed March 14, 2011, 61/453,309, filed March 16, 2011, 61/453,885, filed March 17, 2011, and 61/493,336, filed. June 3, 2011, the contents of which. are hereby incorporated by reference.

Throughout this application, various publications are nced, including referenced in parenthesis. Full citations for publications referenced in parenthesis may be found listed in alphabetical order at the end of the specification immediately preceding the claims. The disclosures of all nced publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains.

Field of the Invention The subject invention relates to combination therapy for treating prostate cancer.

Background of the ion Prostate cancer is the most common cancer that affects men, and the second leading cause of cancer deaths in men in the Western world. Because prostate cancer is an androgen ive tumor, androgen. withdrawal, for example via castration, is utilized in some eutic regimens for patients with. advanced. prostate . Androgen. withdrawal leads to extensive apoptosis in the prostate tumor, and hence to a regression of the disease. However, castration—induced apoptosis is not complete, and a progression of surviving tumor cells to androgen—independence ultimately occurs. This progression is the main le to improving survival and quality of life, and therapies e of treating prostate cancer both before and after the progression to androgen independence are needed.

It has been observed that numerous proteins are expressed in increased s by prostate tumor cells ing androgen withdrawal. At least some of these proteins are assumed to be associated. with. the apoptotic cell death. which. is observed upon androgen withdrawal. (Raffo et al., 1995; Krajewska et al., 1996; McDonnell et al., 1992). The functions of many of the proteins, however, is not completely understood. Clusterin (also known as ed glycoprotein—2 (SGP—2) or TRPM—Z) is within this latter category.

Clusterin Clusterin is a otective chaperone protein that promotes cell survival and confers broad-spectrum resistance to cancer treatments (Chi et al. 2005). in Sensibar et al., Cancer Research 55: 2431—2437, 1995, the authors reported on LNCaP cells transfected with a gene encoding Clusterin, and watched to see if expression of this protein altered the effects of tumor is factor a (TNFd), to which LNCaP cells are very sensitive. Treatment of the transfected LNCaP cells with TNFd was shown to result in a transient se in Clusterin levels for a period. 0" a 'ew hours, but these levels had dissipated by the time DNA fragmentation ing cell death was observed.

As described in U.S. Patent No. 7,534,773, the contents of which are incorporated by reference, enhancement of 2012/000609 tion—induced tumor cell death and delay of the progression of androgen-sensitive cancer cells to androgen— independence may be achieved by inhibiting the expression of clusterin by the cells.

Custirsen Custirsen is a second—generation antisense oligonucleotide that inhibits clusterin expression. Custirsen is designed specifically to bind to a portion of clusterin mRNA, resulting in the inhibition of the tion of clusterin protein. The structure of custirsen is ble, for e, in U.S.

Patent No. 6,900,187, the contents of which are incorporated herein by reference. A broad range of s have shown that custirsen potently regulates the expression of clusterin, facilitates apoptosis, and sensitizes cancerous human prostate, breast, ovarian, lung, renal, r, and melanoma cells to chemotherapy (Miyake et al. 2005), see also, U.S. Patent ation Publication No. 2008/0119425 A1. In a clinical trial for androgen—dependent prostate cancer, the drugs flutamide and buserelin were used together in combination with custirsen, increasing prostate cancer cell apoptosis (Chi et al. 2004; Chi et al., 2005).

Androgen Receptor Antagonists Androgen receptor (AR) antagonists reduce the stimulation of prostate cancer cells by androgens by perturbing or reducing a function of AR, including androgen-AR binding, AR transcriptional ty, or cellular transport of AR such as translocation from the cytoplasm to the s. Custirsen is not an AR antagonist. Custirsen inhibits the progression of prostate cancer to androgen independence by reducing the anti— tic effects of rin and is not thought to affect androgen signaling pathways.

Combination Therapy The administration of two drugs to treat a given condition, such as prostate cancer, raises a number of potential problems. In vivo interactions between two drugs are x.

The effects of any single drug are related to its absorption, distribution, and elimination. When two drugs are introduced into the body, each drug can affect the tion, distribution, and ation of the other and hence, alter the effects of the other. For instance, one drug may inhibit, activate or induce the production of enzymes involved in a metabolic route of elimination of the other drug (Guidance for Industry. In vivo drug lism/drug interaction studies — study design, data analysis, and recommendations for dosing and labeling). Thus, when two drugs are administered to treat the same condition, it is unpredictable whether each will complement, have no effect on, or interfere with, the therapeutic activity of the other in a human subject.

Not only’ may the ction. between. two drugs affect the intended. therapeutic activity of each drug, but the interaction may increase the levels of toxic metabolites (Guidance for Industry. In vivo drug lism/drug interaction studies - study design, data analysis, and recommendations for dosing and labeling). The interaction may also heighten or lessen the side effects of each drug. Hence, upon administration of two drugs to treat a disease, it is unpredictable what change will occur in the profile of each drug.

W0 2012/123820 Additionally, it is difficult to accurately predict when the effects of the interaction between the two drugs will become manifest. For example, metabolic interactions n drugs may" become apparent upon the initial stration of the second drug, after the two have reached a steady-state concentration or upon discontinuation of one of the drugs (Guidance for Industry. In vivo drug metabolism/drug interaction studies — study design, data analysis, and recommendations for dosing and labeling).

Thus, the success of one drug or each drug alone in an in vitro model, an animal model, or in humans, may not ate into efficacy when both drugs are administered to humans. x of the Invention The present invention relates to a method for ng a mammalian subject afflicted. with. prostate cancer comprising administering to the mammalian subject i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure or‘ a ceutically acceptable salt thereof, each. in an amount that when in combination with the other is effective to treat the mammalian subject.

In one aspect of the present invention there is provided a use of i) an oligonucleotide which reduces clusterin expression and ii) an en receptor antagonist having the structure O)__% or a pharmaceutically acceptable salt thereof, in the manufacture of a medicament for treating a mammalian subject ted with prostate cancer. fibflowedbypage6d In a r aspect of the present invention, there is provided a use of i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist, in the cture of a Inedicament for the treatment of a mammalian subject afflicted with androgen—independent prostate cancer.

In a further aspect of the present invention there is provided a. use of custirsen. in the manufacture of a Inedicament for increasing the sensitivity of ARI resistant prostate cancer cells to ARI.

In a further aspect of the present invention there is ed a composition for treating a mammalian subject ted with te cancer comprising i) an oligonucleotide which reduces rin expression and ii) an androgen receptor antagonist having the structure F30 e g f or a pharmaceutically acceptable salt thereof.

Some embodiments of the invention provide a method for treatment of a mammalian subject afflicted with androgen— independent prostate cancer, consisting‘ of administering to the subject i) an oligonucleotide which reduces rin [followed by page 6b] expression, and ii) an androgen receptor antagonist, each in an amount that when in combination with the other is effective to treat the mammalian subject.

An aspect of the present invention provides a ceutical composition comprising an amount of an oligonucleotide which reduces Clusterin expression, and an androgen receptor antagonist for use in treating a mammalian subject afflicted with en—independent prostate cancer. [followed by page 7] —6b- An aspect of the present invention provides an oligonucleotide which s clusterin expression for use in combination with an androgen receptor nist in treating a mammalian subject afflicted with androgen—independent prostate cancer.

An aspect of the t invention provides a composition for treating a mammalian subject afflicted with prostate cancer sing i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure NC k 12 F3C > 4 i or a pharmaceutically acceptable salt thereof.

PCT/IBZOIZIOOO609 Brief Description of the Drawings Figure 1. Inhibition of LNCaP cell eration upon treatment with luM ARl and lOnM siRNA targeting clusterin (CLU) or lOnM SCR. SCR. is a scrambled sequence siRNA control. (A), FBS condition is media supplemented with FBS. (B), CSS condition is charcoal serum stripped media.

Figure 2. Inhibition of LNCaP cell proliferation upon ent with luM ARl and SOOnM custirsen or 500nM SCRB. SCRB is a scrambled sequence antisense oligonucleotide control. (A), FBS condition is media mented with PBS. (B), CSS condition is charcoal serum stripped media.

Figure 3. Inhibition of C4-2 cell proliferation upon treatment with luM ARl and SOOnM custirsen or SOOnM SCBR. (A), FBS condition is media supplemented with FBS. (B), CSS condition is charcoal serum stripped media.

Figure 4. PC—3 (AR—negative) cell eration upon treatment with luM ARl and lOnM siRNA targeting rin or lOnM SCR (A). PC—3 (AR~negative) cell proliferation upon treatment with luM ARl and 500nM custirsen or SOOnM SCRB (B).

Figure 5. Cytotoxicity in LNCaP cells upon treatment with ARl and lOnM siRNA targeting clusterin or 10nM SCR (A).

Cytotoxicity in LNCaP cells upon treatment with luM ARl and SOOnM custirsen or 500nM SCRB (B). Cells grown in media supplemented with PBS. X—axis is ARl concentration.

W0 2012/123820 Figure 6. Potency of ARl and custirsen combination therapy in LNCaP cells. (A), Cell growth inhibition after treatment with each drug or a combination thereof by crystal violet assay. X-axis is [AR1]/[custirsen].

P-value was calculated by the Friedman test. (B), Dose effect curve for each treatment. (C), Combination index (CI) at l effective doses.

CI = i, additive effect; Cl < l, combination effect; C: > ;, antagonistic effect.

Figure 7. Cell Cycle Distribution upon treatment of ARl, siRNA targeting clusterin, or a combination f in LNCaP cells. OTR refers to cells d with oligofectamine transfection reagent (Invitrogen Life Technologies, Inc.) in the absence of custirsen or SiRNA.

Figure 8. FACS Analysis of Cell Cycle Distribution upon treatment of ARl, custirsen, or a combination thereof in LNCaP cells.

Figure 9. Effect of ARl stration on .AR and clusterin protein sion in LNCaP cells. (A), lOuM ARl.

(B), after 48 hours of ARl treatment at indicated concentrations.

Figure 10. Effect of ARl administration on AKT and ERK phosphorylation and protein levels in LNCaP cells.

(A), lOuM ARl. (B), after 48 hours of ARl treatment at indicated concentrations. (C), Dose ent change of expression level of ART or ERK after W0 2012/123820 treatment with ARl. (D), Dose dependent change of expression level of ART or ERK after treatment with ARl .

Figure 11. Effect of ARl administration on AR and clusterin mRNA expression in LNCaP cells. (A), AR mRNA expression 48 hours after adding ARl at each concentration. (B), AR mRNA expression at indicated time points following the addition of lOpM ARl. (C), clusterin mRNA expression 48 hours after adding ARl at each concentration. (D), Clusterin mRNA expression at indicated. time points following the addition of lOnM ARl.

Figure 12. Change of protein expression in LNCAP cells after treatment of siRNA targeting clusterin, custirsen, or ted controls (A and C). (B), comparison of clusterin upregulation by bicalutamide and ARl. (D), Expression of AR perone by treatment with ARl and sen (ASO).

Figure 13. Effect of lOuM ARl and lOnM siRNA targeting clusterin on PSA in LNCaP cells (A), or on AR mRNA expression (B).

Figure 14. Effect 0: lOuM ARl and SOOnM custirsen combination therapy on AR (A), or PSA mRNA expression (B).

Figure 15. Western blot analysis of protein expression and PARP cleavage after ent of LNCaP cells with ARl and lOnM siRNA. targeting clusterin. FBS condition is media supplemented with PBS. CSS condition is charcoal serum stripped media.

Figure 16. Effect of ARl and louM siRNA targeting clusterin on protein‘ levels upon androgen stimulation in LNCaP cells. R1881 is a potent androgen that is also known as metribolone.

Figure 17. n blot analysis of protein expression and PARP cleavage upon treatment of LNCaP cells with ARl and custirsen or control. Cells (leO6) were seeded in 10cm dishes with RPMI medium containing 5% PBS.

The next day, cells were transfected. with SOOnM custirsen or control for 48h. 10pm ARl was then added to the cells for 48 hours before harvesting for Western blot analysis. AR and PSA expression were highly repressed by custirsen and ARl combination therapy.

Figure 18. n blot analysis of n expression and phosphorylation upon treatment of LNCaP cells with ARl and lonM siRNA targeting clusterin, or l.

Phospho—AKT and phosph—ERK are activated by AR1 treatment; however, ARl and. Clu siRNA. combination therapy reduces levels of phosphorylated ART and ERK protein. Combination treatment represses the AKT— mTOR—p7OS6K pathway more ly than erapy.

Figure 19. Western blot analysis of AR proteasome degradation upon treatment of LNCaP cells with a combination of ARl and custirsen or an siRNA targeting clusterin.

M6132 is a proteasome inhibitor, and CHX is cycloheximide, an tor of protein biosynthesis.

AR protein degradation is potently increased by ARl and custirsen combination therapy.

Figure 20. Effect of ARl and custirsen combination therapy on AR transcriptional activity. Dual luciferase assay; LNCaP cells were transfected for 2 days with SOOnM custirsen in CSS. ARl (luM) or DMSO was then added with or without R1881 (1nM) for 24 hours before ting for is.

Figure 21. Increased inhibition of AR ocation from the cytoplasm to the nucleus upon combination of lonM siRNA targeting clusterin with louM ARl compared to monotherapy. LNCaP cells were used.

Figure 22. Increased inhibition of AR translocation from the cytoplasm to the nucleus upon combination of lonM siRNA targeting clusterin with lOuM ARl ed to monotherapy. LNCaP cells were used.

Figure 23. Increased, association. of AR. with. ubiquitin upon combination treatment of lOuM ARl and 10nM siRNA targeting clusterin compared to monotherapy (A).

Association of ARV with. ubiquitin. upon combination treatment of louM ARl and lOnM siRNA targeting Clusterin, or control in the presence of MG132 (B).

LNCaP cells were used.

Figure 24. Comparison of clusterin knock—down between treatment of bicalutamide or ARl, in ation with custirsen (ASO) or control in LNCaP cells.

PCT/IBZOIZIOOO609 Figure 25. Effect of (FKBP52) over—expression on AR degradation and clusterin knock-down in LNCaP cells.

Figure 26. Decreased tion-resistant prostate cancer tumor growth and increased survival upon combination treatment of ARl and custirsen in mice. Male athymic nude mice were injected s.c. in two sites with LNCaP cells in Matrigel. The mice were castrated once tumors reached 150mm3 or‘ the PSA. level increased above 50ng/mL. Once tumors progressed to castration resistance (PSA levels increased to the same level as pre—castration), 10 mice were randomly assigned to each of ARl + led antisense oligonucleotide (SCRB) or ARl + custirsen. Custirsen (lOmg/kg/each dose) or SCRB (lOmg/kg/each dose) was injected i.p. once daily for the first week and then three times per week. ARl (lOmg/kg/each dose) was administered orally once daily ng) 7 days per week for 8 to 12 weeks.

Figure 27. Increased survival upon combination treatment of ARl and sen in mice. Male athymic nude mice were injected s.c. in two sites with LNCaP cells in el. The mice were castrated once tumors reached lSOHm§ or the PSA level increased above 50ng/mL. Once tumors progressed to castration resistance (PSA levels increased to the same level as pre-castration), 10 mice were randomly assigned to each of ARI + scrambled antisense oligonucleotide (SCRB) or ARl + sen. Custirsen (lOmg/kg/each dose) or SCRB (lOmg/kg/each dose) was injected i.p. 2012/000609 once daily for the first week and then three times per week. ARl (lOmg/kg/each dose) was administered orally once daily ng) 7 days per week for 8 to 12 weeks.

Figure 28. Decreased PSA protein expression upon combination treatment of ARl and custirsen in mice. Male athymic nude mice were injected s.c. in two sites with LNCaP cells in Matrigel. The mice were castrated once tumors reached 150mm3 or the PSA. level increased above 50ng/mL. Once tumors progressed to castration resistance (PSA levels increased to the same level as pre-castration), 10 mice were randomly assigned to each of ARl + scrambled antisense oligonucleotide (SCRB) or ARl + custirsen. Custirsen (lOmg/kg/each dose) or SCRB (lOmg/kg/each dose) was injected i.p. once daily for the first week and then three times per week. ARl (lOmg/kg/each dose) was administered orally once daily (morning) 7 days per week for 8 to 12 weeks.

Figure 29. Decreased PSA protein expression upon combination treatment of ARl and custirsen in mice. Male athymic nude mice were injected s.c. in two sites with LNCaP cells in Matrigel. The mice were castrated once tumors reached. lSOHm9 or the PSA level increased above 50ng/mL. Once tumors progressed to castration resistance (PSA levels increased to the same level as stration), 10 mice were randomly assigned to each of ARI + led antisense oligonucleotide (SCRB) or ARl + custirsen. Custirsen kg/each dose) or SCRB (lOmg/kg/each dose) was injected i.p. once daily for the first week and then three times per week. ARl (lOmg/kg/each dose) was stered orally once daily (morning) 7 days per week for 8 to 12 weeks.

Figure 30. Clusterin expression is induced in ARl resistant tumors. (A) Increased clusterin expression ing ARl treatment. (B) Increased. clusterin expression following ARl treatment in ARl resistant tumors. (C) Clusterin expression is up—regulated in a time and dose dependent manner after ARl treatment, as determined by Western blot analysis.

Figure 31. Combination treatment of custirsen and ARl is more effective than custirsen or ARl monotherapy in CRPC LNCaP xenografts. ARl plus custirsen treatment decreased AR and PSA expression in CRPC xenografts.

Figure 32 . Clusterin knockdown decreases AR. transcriptional activity and expression of AR—dependent genes.

Transmembrane protease serine 2 (TMPRSSZ) mRNA levels sed following ARl treatment, clusterin knockdown, and ARl treatment plus clusterin knockdown.

Figure 33 . Clusterin knockdown ses AR. protein levels when ed. with. ARl. The le interaction between heat shock protein 27 (Hsp27) and AR contributing to AR transcriptional activity, PSA expression, and cell survival is depicted.

Figure 34. clusterin. knockdown. decreases heat shock factor protein 1 ) transcription. ty and expression of heat shock proteins.

Figure 35. Clusterin overexpression increases HSF—l activity.

Figure 36. Possible mechanism of action for ARl treatment plus custirsen treatment in a tumor cell.

Figure 37. clusterin and autophagy may play a role in stress and cancer. Increased clusterin expression following asmic reticulum (ER) stress, chemo~stress, and androgen deprivation is depicted.

Figure 38. ARl treatment induces autophagy in LNCaP cells.

Figure 39. Treatment stressors induce clusterin which co— localizes with LC3B in aggresomes.

Figure 40. ER stress—induced autophagy is inhibited by clusterin silencing.

Figure 41. CLU is induced by ARl and highly expressed in ARl resistant cells. C, Dose and time dependent ARl induction. of CLUL D, CLU‘ is also induced. in .ARl resistant cells by AR knock down. AR ASO also induces CLU in several ARl ant MR49F cells.

CLU is high in ARl resistant cells, e.g. MR49F.

Figure 42. ion of stress response (ER, YB—l), as well as cross talk of pAKT and MAPK. (followed by page 16a) Figure 43. The combination of CLU inhibition and ARI increases inhibition of LNCaP cell growth compared to CLU inhibition or AR1 monotherapy.

Figure 44. s of combination treatment on tumor volume and serum PSA level.

Figure 45. Effect of combination treatment on AR transactivation and ocation. A, Custirsen combined with AR1 treatment decreases AR transactivation more than custirsen or ARl monotherapy. LNCaP cells were transfected 500 nmol/L of custirsen or SCRB control for 2 consecutive days, and at day 2, transiently cotransfected with 1 ug of PSA—luciferase and Renilla-luciferase. On the next day, the cells were treated 10 umol/L of AR1, then added 1 nmol/L of R1881 or vehicle for 24 h. Cells were harvested, and luciferase activity was determined. Columns ent means of at least three independent experiments done in triplicate.

PSA activation was normalized Renilla—luciferase activity. B, Effect of AR translocation by ation treatment. 24 hours after transfection with 10 nmol/L of CLU siRNA or SCR siRNA control, LNCaP cells were treated with DMSO, 10 pmol/L of ARl and 1nmol/L of R1881 for 30 minutes and fixed in methanol/acetone for immunofluorescence staining with anti—AR antibody. Nuclei were stained with DAPI. ARl inhibited AR translocation from the cytoplasm to the nucleus. CLU knockdown combined with ARl shows increased effects of tion of AR translocation. —16a— (followed by page 17) Figure 46. The effect of CLU own combined with ARl on AR expression.

Figure 47. Western Blot Analysis following CLU knockdown. (followed by page 18) Detailed Description of the Invention The present ion relates to a method for treating a mammalian subject tedv with. prostate cancer comprising stering to the mammalian subject i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure NC /JL\ IZ QC 9 é o :’ or‘ a pharmaceutically‘ acceptable salt thereof, each. in an amount that when in combination with the other is effective to treat the mammalian subject.

In some embodiments of the invention the cancer is androgen— independent prostate cancer.

In some embodiments, the amount of the oligonucleotide and the amount of the androgen receptor nist or a pharmaceutically acceptable salt thereof when taken together is more effective to treat the subject than when each agent is administered alone.

In some embodiments, the amount of the oligonucleotide in combination with the amount of the androgen receptor antagonist cm: a pharmaceutically acceptable salt thereof is less than is ally ive when administered alone. -18— 2012/000609 In some embodiments, the amount of the androgen receptor antagonist or a pharmaceutically able salt thereof in combination with the amount of the oligonucleotide is less than is clinically effective when administered alone.

In some embodiments, the amount of the oligonucleotide and the amount of the androgen receptor antagonist or a ceutically acceptable salt thereof when taken together is effective to reduce a clinical symptom of prostate cancer in the subject.

In some embodiments, the mammalian subject is human.

In some embodiments, the oligonucleotide is an antisense oligonucleotide.

In some embodiments, the antisense oligonucleotide spans either the translation initiation site or the ation site of clusterin—encoding mRNA.

In some embodiments, the antisense oligonucleotide is modified to enhance in vivo stability relative to an unmodified oligonucleotide of the same sequence.

In some embodiments the antisense oligonucleotide consists ially of an ucleotide selected from the group consisting of Seq. ID Nos. 1 to 11.

In some embodiments, the antisense oligonucleotide consists essentially of an oligonucleotide consisting of Seq. ID No. 3.

In some ments, the oligonucleotide is custirsen.

In some embodiments, the amount of custirsen is less than 640mg.

In some embodiments, the amount of custirsen is less than 480mg.

In some embodiments, the amount of custirsen is stered intravenously once in a seven day period.

In some embodiments, the amount of the androgen receptor antagonist is less than 240mg.

In some ments, the amount of the androgen receptor antagonist is from 150mg to 240mg.

In some embodiments, the amount of the androgen receptor antagonist is from 30mg to 150mg.

In some embodiments, the amount of the en receptor antagonist is 80mg.

In some embodiments, the amount of the androgen receptor antagonist is administered orally once per day.

Some embodiments of the invention provide a method for treatment of a mammalian subject afflicted. with androgen— independent prostate cancer, consisting of administering to the subject i) an androgen receptor antagonist and ii) an oligonucleotide which s clusterin expression, each in an amount that when in ation with the other is effective to treat the mammalian subject.

In some embodiments the androgen receptor antagonist is a non- steroidal antiandrogen.

In some embodiments, the androgen receptor antagonist is ARl.

In some embodiments, the androgen—independent prostate cancer is resistant to ARl.

In some ments the combination of the androgen receptor antagonist and the oligonucleotide is effective to decrease androgen receptor translocation from the cytoplasm to the s of the tumor cells.

In some embodiments, the combination of the androgen receptor nist and the oligonucleotide is ive to increase the proteasome degradation of the androgen receptor protein in the tumor cells. in some embodiments, the combination of the androgen receptor antagonist and. the oligonucleotide is effective to decrease androgen receptor riptional activity in the tumor cells.

In some embodiments, the combination of the androgen or antagonist and the oligonucleotide is effective to decrease the amount of phosphorylated AKT in the tumor cells.

In some embodiments, the ation of the androgen receptor antagonist and the oligonucleotide is effective to decrease the amount of phosphorylated ERK in the tumor cells.

W0 2012/123820 In some embodiments, the combination of the androgen or antagonist and the ucleotide is ive to inhibit the proliferation of prostate cancer cells.

Some embodiments of the invention provide a Hethod by which ARl resistant prostate cancer cells are sensitized to ARl by concomitant treatment with custirsen.

Some embodiments of the ion provide a method of increasing the sensitivity of ARl resistant prostate cancer cells to ARI comprising treating the ARl resistant prostate cancer cells with custirsen.

Some embodiments of the invention provide a method for treatment of a mammalian subject afflicted with prostate cancer that is resistant to ARl, comprising stering to the subject i) ARl and ii) custirsen, each in an amount that when in combination with the other is effective to treat the mammalian subject, wherein the custirsen increases the sensitivity of the prostate cancer to ARl.

An aspect of the present invention provides a pharmaceutical composition comprising an amount of an oligonucleotide which reduces clusterin expression, and an en or antagonist for use in treating a mammalian subject afflicted with androgen-independent prostate cancer.

An aspect of the t invention provides an oligonucleotide which reduces clusterin expression for use in combination with an androgen receptor antagonist in treating a ian subject afflicted with androgen-independent prostate cancer.

An aspect of the present ion provides a composition for treating a mammalian subject ted with te cancer comprising i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure go > g , or a pharmaceutically able salt thereof.

Aspects of the invention involve the increased potency of the combination of an oligonucleotide which. decreases clusterin expression and an AR antagonist in the treatment of prostate cancer compared to ucleotide or AR antagonist monotherapy. Increased potency es but is not limited to reduced proliferation of prostate cancer cells, increased apoptosis of cancer cells, reduced ocation of AR from the cytoplasm to the nucleus, reduced transcriptional activity of AR, increased PARP cleavage, reduced AKT phosphorylation, reduced. ERK phosphorylation, and increased. AR protein degradation. in embodiments in which AKT and/or IERK phosphorylation is reduced, all isoforms of AKT and ERK are envisioned. This includes but is not limited to AKTl, AKTZ, AKT3, ERK1, and ERKZ. In some embodiments, the increased some degradation of AR involves the increased association of AR with ubiquitin.

Each embodiment disclosed herein is contemplated as being applicable to each of the other disclosed embodiments. Thus, all combinations of the s elements described herein are within the scope of the invention.

It is understood that where a parameter range is provided, all integers within that range, and tenths thereof, are also provided by the invention. For example, “0.2—5 mg/kg/day” includes 0.2 mg/kg/day, 0.3 mg/kg/day, 0.4 mg/kg/day, 0.5 day, 0.6 mg/kg/day etc. up to 5.0 mg/kg/day.

Terms As used, herein, and unless stated otherwise, each. of the following terms shall have the tion set forth below.

As used herein, “about” in the context of a numerical value or range means i10% of the numerical value or range recited or claimed.

As used in the specification and claims of this application, the term "clusterin" refers to a glycoprotein t in mammals, including , and denominated as such in the humans. The sequences of numerous clusterin species are known.

For example, the sequence of human clusterin is described by Wong et al., Eur. J. Biochem. 221 (3),9l7—925 (1994), and in NCBI sequence accession number NM_001831 (SEQ ID NO: 43). In this human sequence, the coding ce spans bases 48 to 1397.

As used herein, “oligonucleotide which reduces clusterin sion” is an oligonucleotide with a sequence which is effective to reduce clusterin expression in a cell. The oligonucleotide which reduces clusterin expression may be, for example, an antisense oligonucleotide or an RNA interference inducing molecule.

As used , “antisense oligonucleotide” refers to a non- RNAi oligonucleotide that reduces clusterin sion and that has a sequence complementary to rin mRNA. Antisense oligonucleotides may be antisense oligodeoxynucleotides (ODN).

Exemplary sequences which can be employed as antisense molecules in the invention are disclosed in PCT Patent Publication WO 37, U.S. Patent Publication No. US 2002— 0128220 Al, and U.S. Patent No. 6,383,808, all of which are incorporated herein by reference. Specific antisense sequences are set forth in the present application as SEQ ID NOS: 1 to 11, and may be found in Table l.

Table 1. Sequence Identification s for Antisense oligonucleotides SEQ ID NO: Sequence 1 GCACAGCAGG AGAATCTTCA T 2 TGGAGTCTTT GCACGCCTCG G 3 CAGCAGCAGA GTCTTCATCA T 4 ATTGTCTGAG ACCGTCTGGT C CCTTCAGCTT TGTCTCTGAT T 6 AGCAGGGAGT CGATGCGGTC A 7 ATCAAGCTGC GGACGATGCG G 8 AGCC CGTGGAGTTG T 9 TTCAGCTGCT CCAGCAAGGA G AATTTAGGGT TCTTCCTGGA G CGGA GTTGGGGGCC T The ODNs employed may be modified to increase the stability of the ODN’ in ViVO. For example, the ODNs may‘ be employed. as phosphorothioate derivatives (replacement of a non—bridging phosphoryl oxygen atom with a sulfur atom) which have increased ance to nuclease digestion. MOE (2’—O—(2—methoxyethyl)) modification (ISIS backbone) is also effective. The construction of such modified ODNs is described in detail in U.S. Patent No. 6,900,187 B2, the contents of which are incorporated. by reference. In some embodiments, the ODN is custirsen.

As used herein, “custirsen” refers to an antisense ucleotide that reduces clusterin. expression. having the sequence CAGCAGCAGAGTCTTCATCAT (Seq. ID No.: 3), wherein the anti—clusterin oligonucleotide has a orothioate backbone hout, has sugar‘ moieties of nucleotides 1—4 and 18—21 bearing 2’-O-methoxyethyl cations, has nucleotides 5—17 which are 2’deoxynucleotides, and has 5—methylcytosines at nucleotides 1, 4, and 19. sen is also known as TV—lOll, OGX—Oll, ISIS 112989 and Custirsen Sodium.

As used herein, “RNA interference inducing molecule” refers to a molecule capable of inducing RNA interference or “RNAi” of clusterin expression. RNAi involves mRNA degradation, but many of the biochemical mechanisms underlying this interference are unknown. The use of RNAi has been described in Fire et al., ~26- W0 2012/123820 1998, CartheW' et al., 2001, and. Elbashir‘ et a1., 2001, the contents of which are incorporated herein by reference.

Isolated RNA molecules can mediate RNAi. That is, the isolated RNA molecules of the present invention mediate degradation or block expression of mRNA that is the transcriptional product of the gene, which is also referred to as a target gene. For convenience, such mRNA may also be referred to herein as mRNA to be degraded. The terms RNA, RNA le(s), RNA segment(s) and RNA fragment(s) may be used interchangeably to refer to RNA that mediates RNA interference. These terms include double-stranded. RNA, small interfering‘ RNA (siRNA), hairpin RNA, single—stranded. RNA, isolated. RNA (partially' ed RNA, essentially pure RNA, tic RNA, recombinantly produced RNA), as well as altered RNA that s from naturally occurring RNA by the addition, deletion, substitution and/or alteration of one or more nucleotides.

Such alterations can include addition of non—nucleotide material, such as to the end(s) of the RNA or internally (at one or more nucleotides of the RNA). Nucleotides in the RNA les of the present invention can also comprise nonstandard nucleotides, including non-naturally occurring tides or deoxyribonucleotides. Collectively, all such altered RNAi molecules are referred to as analogs or analogs of naturally-occurring RNA. RNA of the present invention need only be sufficiently similar to l RNA that it has the ability to mediate RNAi.

As used herein the phrase "mediate RNAi" refers to and indicates the ability to distinguish which mRNA molecules are to be afflicted with the RNAi machinery or process. RNA that mediates RNAi interacts with the RNAi machinery such that it WO 23820 directs the machinery to degrade particular mRNAs or to otherwise reduce the expression of the target protein. In one embodiment, the t invention relates to RNA. les that direct cleavage of specific mRNA to which their sequence corresponds. It is not ary that there be perfect pondence of the sequences, but the correspondence must be sufficient to enable the RNA to direct RNAi inhibition by cleavage or blocking expression of the target mRNA.

As noted above, the RNA molecules of the present invention in general comprise an RNA portion and some additional portion, for example a deoxyribonucleotide portion. The total number of nucleotides in the RNA le is suitably less than in order to be effective mediators of RNAi. In preferred RNA les, the number of nucleotides is 16 to 29, more preferably 18 to 23, and most preferably 21-23. Suitable sequences are set forth in the present application as SEQ ID N08: 19 to 42 (Table 2).

Table 2. Sequence Identification Numbers for RNA Interference Inducing Molecules SEQ ID NO: Sequence NNNNNNNNNH GSU'IhUJNi—‘OKO CCAGAGCUCG CCCUUCUACT T GUAGAAGGGC GAGCUCUGGT T CAAC ACCUCCUCCT T GGAGGAGGUG UUGAGCAUCT T UAAUUCAACA AAACUGUTT GACAGUUUUA UUGAAUUAGT T UAAUUCAACA AAACUGUTT ACAGUUUUGU UGAAUUATT 7 AUGAUGAAGA CUCUGCUGCT T 8 GCAGCAGAGU CUUCAUCAUT T _ GUAGAAGGGC GAGCUCUGGT T GUCCCGCAUC GUCCGCAGCT T — GCUGCGGACG AUGCGGGACT T GACAGUUUUA UUGAAUUAGT T AUGAUGAAGA CUCUGCUGC GCAGCAGAGU CUUCAUCAU The siRNA molecules of the invention are used in therapy to treat patients, including human patients, that have cancers or other diseases of a type where a therapeutic benefit is obtained by the inhibition of expression of the targeted protein. siRNA molecules of the invention are administered to patients by one or more daily ions (intravenous, subcutaneous or hecal) or by continuous intravenous or intrathecal stration for one or more treatment cycles to reach plasma and tissue concentrations suitable for the regulation of the ed mRNA and protein.

As used herein, a “mammalian subject afflicted with prostate cancer” means a mammalian t who was been affirmatively diagnosed to have prostate cancer.

As used herein, “androgen-independent prostate cancer” encompasses cells, and tumors predominantly containing cells, that are not androgen—dependent (not androgen sensitive). Often -29_ W0 2012/123820 androgen—dependent cells progress from being androgen-dependent to being androgen-independent. Additionally, in some ments androgen—independent prostate cancer may encompass a tumor that overall is not androgen—dependent (not androgen sensitive) for growth. In some embodiments, androgen independent prostate cancer has progressed since the administration of e ablation y and/or the administration of an AR antagonist (as in hormone blockade therapY). In some embodiments, there is increased AR expression in the androgen—independent prostate cancer ed to prostate cancer that is not androgen—independent.

As used herein, “castration-resistant prostate cancer” encompasses any androgen—independent ‘prostate cancer that is resistant to hormone ablation therapy or hormone blockade therapy. In some embodiments, castration-resistant prostate cancer has progressed since the administration of hormone ablation and/or hormone blockade therapy. In some embodiments, there is increased th expression ill the castration—resistant te cancer compared to prostate cancer that is not castration resistant.

As used herein, “androgen—withdrawal” encompasses a reduction in the level of an androgen in a patient afflicted with prostate cancer.

As used herein, “hormone blockade therapy” means a reduction in the function of receptors or cellular pathways that respond to an en. A. non—limiting' example of a e de therapy is an AR antagonist.

As used herein “androgen ablation therapy” is any therapy that is capable of causing androgen-withdrawal in a mammalian subject afflicted with prostate cancer. Terms used herein that are synonymous with en ablation therapy, are “androgen withdrawal” and “hormone ablation therapy”. Non-limiting es of androgen ablation therapies include both surgical (removal of both testicals) and l (drug induced ssion of testosterone or testosterone induced signaling) castration. Medical castration can be achieved. by various regimens, ing but not limited to LHRH agents, and agents that reduce androgen expression from. a gland such as the adrenal glands (Gleave et al., 1999; Gleave et al., 1998).

As used herein, “AR antagonist” refers to an agent that perturbs or reduces a function of AR, including androgen binding, AR ing, cellular transport of AR such as translocation front the cytoplasnl to the nucleus, AR. protein levels, or AR protein expression. AR antagonists include but are not limited to AR-specific monoclonal antibodies, oligonucleotides that target AR expression (such as AR— targeting antisense oligonucleotides or RNA inducing molecules), peptide agents specific for AR, and small molecule inhibitors specific for AR. An AR antagonist may be ea non— steroidal antiandrogen such. as ARl, bicalutamide, ide, nilutamide, RDl62, and ZD4054.

ARl is an AR antagonist of the ion having the structure: F3C 2 g ,- 2012/000609 Methods of synthesis for ARl are described in U.S. Patent No. 7,709,517 B2, the contents of which are incorporated herein by reference. Alternatively, AR1 may be ed from Medivation, Inc. (San sco, California, USA). The CAS Registry No. for ARl is 915087—33—1, and its PubChem No. is 15951529. AR1 has the chemical formula. C2fih5F4N4028, and. is also known as MDV3100 and 4-(3—(4—cyano—3—(trifluoromethyl)phenyl)—5,5— dimethyl—4~oxo—2~thioxoimidazolidinyl)~2~fluoro-N- methylbenzamide. ARl is a second generation orally available AR nist that works by blocking androgen binding to AR, impeding the r ocation of AR from the cytoplasm, and inhibiting AR-DNA. binding (Tran et al. 2009). ARl is currently being evaluated in clinical trials for the treatment of advanced prostate cancer (Scher et al., 2010).

As used herein, “transcriptional activity” refers to a protein’s ability to bind or otherwise become directly or indirectly ated with a portion of DNA in a cell resulting in an influence on the level of expression of one or more genes.

The inhibition of clusterin expression may be transient, and may occur in combination with androgen ablation therapy or administration of an AR antagonist. In humans with. prostate cancer that is not androgen—independent, this means that inhibition of expression should be effective starting within a day or two of androgen withdrawal or administration of an AR antagonist, and ing for about 3 to 6 months thereafter.

This may require Inultiple doses to accomplish. It will be appreciated, however, that the period of time may be more prolonged, starting before castration and extending for W0 2012/123820 ntial time afterwards t departing from the scope of the invention.

Aspects of the invention can be applied to the treatment of en-independent prostate cancer, or to prevent prostate cancer from becoming androgen-independent.

Aspects of the invention can be applied to the treatment of castration—resistant ate cancer, or 11) prevent prostate cancer from becoming castration—resistant. nation” means either at the same time and frequency, or more usually, at different times and frequencies than an oligonucleotide which reduces clusterin expression, as part of a single treatment plan. Aspects of the invention include the administration of the oligonucleotide before, after, and/or during the administration of an AR antagonist. An AR antagonist may therefore be used, in combination with the oligonucleotide according to the invention, but yet be administered at different times, different dosages, and at a different frequency, than a oligonucleotide which reduces clusterin expression.

As used herein, an “amount” or “dose” of an oligonucleotide measured in rams refers to the milligrams of oligonucleotide t in a drug product, regardless of the form of the drug product.

As used herein, “effective” when referring to an amount of oligonucleotide which reduces clusterin expression, an AR antagonist, or any combination thereof refers to the ty of oligonucleotide, AR antagonist, or any combination thereof that is sufficient to yield. a desired. therapeutic response without undue adverse side s (such as toxicity, irritation, or allergic response) commensurate with a reasonable benefit/risk ratio when used in the manner of this invention.

As used herein, “treating” encompasses, e.g., inhibition, regression, or stasis of the progression of prostate cancer.

Treating also encompasses the prevention or amelioration of any symptom or symptoms of te cancer.

As used herein, “inhibition” of disease progression or disease complication in a subject means preventing' or reducing' the disease progression and/or disease complication in the subject.

As used herein, a “symptom” associated with prostate cancer es any al or tory manifestation associated with prostate cancer, and is not limited to what the subject can feel or observe.

As used herein, “pharmaceutically acceptable r” refers to a r or excipient that is suitable for use with humans and/or animals without undue adverse side effects (such as ty, irritation, and allergic response) commensurate with a reasonable benefit/risk ratio. It can be a pharmaceutically acceptable solvent, suspending agent or vehicle, for delivering the instant compounds and/or combinations to the subject.

Dosage Units Administration of an oligonucleotide that targets rin expression can be carried out using the various mechanisms known in the art, including naked administration and administration in pharmaceutically acceptable lipid carriers.

For example, lipid carriers for antisense delivery are sed in U.S. Patent Nos. 5,855,911 and 5,417,978, which are incorporated herein by nce. In general, the oligonucleotide is administered by intravenous (i.v.), intraperitoneal (i.p.), subcutaneous (8.0.), or oral routes, or direct local tumor injection. In red, embodiments, an oligonucleotide targeting rin expression is administered by i.v. injection. In some embodiments, the amount or ucleotide administered is 640mg.

The amount of oligonucleotide administered is one effective to inhibit the expression of rin in prostate cells. It will be appreciated that this amount will vary both with the effectiveness of the oligonucleotide employed, and. with the nature of any carrier used.

The amount of antisense oligonucleotide targeting rin expression administered may be from 40 to 640 mg, or 300—640 mg. Administration of the antisense oligonucleotide may be once in a seven day period, 3 times a week, or more specifically on days 1, 3 and 5, or 3, 5 and 7 of a seven day period. In some embodiments, administration of the antisense oligonucleotide is less frequent than once in a seven day period. Dosages may be calculated by patient weight, and therefore a dose range of about 1—20 mg/kg, or about 2-10 mg/kg, or about 3—7 mg/kg, or about 3—4 mg/kg' could. be used. This dosage is repeated. at intervals as needed. One al concept is dosing once per week with 3 loading doses during week one of treatment. The amount of antisense oligonucleotide administered is one that WO 23820 has been demonstrated. to be effective in human patients to inhibit the expression of clusterin in cancer cells.

In some embodiments of the invention, the amount of oligonucleotide targeting the expression of clusterin required for treatment of prostate cancer is less in ation with an AR antagonist, than would. be required. with oligonucleotide monotherapy.

Custirsen may be formulated at a concentration of 20 mg/mL as an isotonic, phosphate-buffered saline on for IV administration and can be supplied as an 8 mL solution containing 160 mg custirsen sodium in a single vial.

Custirsen may be added to 250 mL 0.9% sodium chloride (normal ). The dose may be administered using either a peripheral or central indwelling catheter enously as an infusion over 2 hours. Additionally, an infusion pump may be used.

Administration of an AR antagonist may be oral, nasal, pulmonary, parenteral, i.v., i.p., intra—articular, transdermal, intradermal, s.c., l, intramuscular, rectal, intrathecal, intraocular, and buccal. A, preferred route of administration for ARl is oral. One of skill in the art will recognize that higher doses may be required for oral stration of an AR antagonist than for i.v. injection.

The dose of an AR antagonist may be 30mg, 35mg, 40mg, 45mg, 50mg, 55mg, 60mg, 65mg, 70mg, 75mg, 80mg, 85mg, 90mg, 95mg, 100mg, 150mg, 240mg, 360mg, 480mg, or 600mg. In some embodiments, the dose of an AR antagonist is less than 30mg. In these embodiments the dose may be as low as 25mg, 20mg, 15mg, —36- 10mg, 5mg, or less. In some ments, the dose of an AR antagonist is administered daily. In some embodiments the dose is administered orally.

A dosage unit of the oligonucleotide which reduces clusterin expression and an AR antagonist may comprise one of each singly or mixtures thereof. A combination of an oligonucleotide which reduces clusterin. expression and. ARl can be administered. in oral dosage forms as tablets, capsules, pills, powders, granules, elixirs, tinctures, suspensions, syrups, and ons. An oligonucleotide which reduces clusterin expression and/or an AR antagonist may also be administered in intravenous (bolus or infusion), intraperitoneal, subcutaneous, or uscular form, or introduced directly, e.g. by injection or other methods, into or onto a jprostate cancer , all using dosage forms well known to those of ordinary skill in the pharmaceutical arts.

An oligonucleotide which reduces clusterin expression and/or an AR antagonist of the invention can be administered in admixture with le pharmaceutical diluents, extenders, excipients, or carriers (collectively referred to herein as a pharmaceutically acceptable r) suitably selected with respect to the intended form of administration and as consistent with tional pharmaceutical practices. The unit will be in a form le for oral, rectal, topical, intravenous or direct injection or parenteral administration.

An oligonucleotide which reduces rin expression and/or an AR antagonist can be administered alone or mixed with a pharmaceutically acceptable carrier. This carrier can be a solid or , and the type of carrier is generally chosen based on the type of administration being used. Capsule or tablets can be easily formulated and can be made easy to w or chew; other solid forms include granules, and bulk powders. Tablets may contain suitable binders, ants, diluents, disintegrating agents, coloring , flavoring agents, flow-inducing agents, and melting agents. Examples of suitable liquid dosage forms include solutions or sions in water, pharmaceutically able fats and oils, alcohols or other organic solvents, including esters, emulsions, syrups or elixirs, sions, solutions and/or suspensions reconstituted from non—effervescent es and effervescent preparations reconstituted from effervescent granules. Such liquid dosage forms may contain, for e, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents. Oral dosage forms optionally n flavorants and coloring agents.

Parenteral and intravenous forms may also include minerals and other materials to make them compatible with the type of injection or delivery system chosen.

An oligonucleotide which reduces clusterin expression and/or an AR antagonist can also be administered in the form of liposome delivery systems, such. as small unilamellar vesicles, large allar vesicles, and multilamellar vesicles. Liposomes can be formed from a variety of phospholipids, such as cholesterol, stearylamine, or phosphatidylcholines. The compounds may be administered as components of tissue-targeted emulsions.

For oral administration in liquid, dosage form, ARl may be combined with any oral, non—toxic, pharmaceutically acceptable inert r such as ethanol, glycerol, water, and the like.

Examples of suitable liquid dosage forms include solutions or suspensions in water, pharmaceutically acceptable fats and PCT/11320122000609 oils, alcohols or other c solvents, including esters, ons, syrups or elixirs, suspensions, solutions and/or suspensions reconstituted from non-effervescent granules and effervescent preparations reconstituted. from. effervescent es. Such liquid dosage forms may contain, for example, suitable solvents, preservatives, emulsifying agents, suspending agents, diluents, sweeteners, thickeners, and melting agents. in some embodiments of the invention, the amount of AR antagonist required for ent of prostate cancer is less in combination with an oligonucleotide targeting the expression of clusterin, than would. be required. with AR antagonist monotherapy.

A dosage unit may se a single compound or Huxtures of compounds. A dosage unit can be prepared for oral or injection dosage forms.

According to an aspect of the invention, there is provided an oligonucleotide which reduces clusterin expression—containing pharmaceutical composition packaged in dosage unit form, wherein the amount of the oligonucleotide in each dosage unit is 640mg or less. Said pharmaceutical composition may include an AR. antagonist, and. may be in an injectable on or suspension, which may further n sodium ions.

According to another aspect of the invention, there is provided the use of an oligonucleotide targeting clusterin expression and an AR antagonist in the manufacture of a ment for the treatment of cancer, where the medicament is ated to deliver a dosage of 640mg or less of oligonucleotide to a patient. The medicament may contain sodium ions, and/or be in the form of an injectable solution.

General techniques and compositions for making dosage forms useful in the present invention are bed in the following references: 7 Modern Pharmaceutics, Chapters 9 and 10 (Banker & Rhodes, Editors, 1979); Pharmaceutical Dosage Forms: s (Lieberman et al., 1981); Ansel, Introduction to Pharmaceutical Dosage Forms 2nd. Edition (1976); Remington's Pharmaceutical Sciences, 17th ed. (Mack Publishing Company, , Pa., 1985); Advances in Pharmaceutical Sciences (David. Ganderton, Trevor Jones, Eds., 1992); Advances in Pharmaceutical es Vol 7. (David Ganderton, Trevor Jones, James McGinity, Eds., 1995); Aqueous Polymeric Coatings for Pharmaceutical Dosage Forms (Drugs and the Pharmaceutical es, Series 36 (James McGinity, Ed., 1989); Pharmaceutical Particulate rs: Therapeutic Applications: Drugs and the Pharmaceutical Sciences, Vol 61 (Alain d, Ed., 1993); Drug Delivery to the Gastrointestinal Tract (Ellis Horwood Books in the Biological Sciences. Series in Pharmaceutical Technology; J. G.

Hardy, S. S. Davis, Clive G. Wilson, Eds.); Modern Pharmaceutics Drugs and the ceutical Sciences, Vol. 40 (Gilbert S. Banker, Christopher T. Rhodes, Eds.). These references in their entireties are hereby incorporated by reference into this application.

This invention will be better understood by reference to the mental Details which follow, but those skilled in the art will readily appreciate that the specific experiments detailed are only illustrative of the invention as described more fully in the claims which follow thereafter.

W0 2012/123820 Experimental Details Example 1. Clusterin inhibitor Custirsen together with AR nist ARI is a potent combination therapy in castrationresistant te cancer models.

Introduction and Objective AR and intra-tumoral androgen synthesis are implicated in promoting tumor cell survival and development of castration— resistant prostate cancer (CRPC). ARl, has shown ty in preclinical and clinical studies. Previous studies link androgen ablation therapy with clusterin upregulation and castration resistance. The antisense inhibitor, custirsen, increases cell death when ed with castration or chemotherapy in prostate cancer (CaP) models. Herein below, the y of custirsen and ARl combination therapy to delay progression in a castration—resistant LNCaP model was tested.

Methods Effects of dual vs ation ARl and custirsen regimens on AR—positive LNCaP cell proliferation (Figures 1—4, and 6-7) and al (Figure 5) as well as protein (Figures 9, 11, and 13-15), and gene expression (Figures 13 and 14) were analyzed using a crystal violet assay, flow cytometry, western blotting and RT-PCR, respectively. AR transcriptional activity was measured. by a ciferase reporter assay, while AR, degradation was assessed. by' a cycloheximide chase assay. The LNCaP cell line used for experiments was AR positive.

The effects of combination treatment on castration—resistant LNCaP tumor' growth. were assessed. in ted. male athymic nude mice. Male athymic nude mice were inoculated with LNCaP cells in Matrigel in two sites of mouse flank lesion. The mice were castrated once tumors reached 150mm3 or the PSA level increased above SOng/mL. Once tumors ssed to castration resistance (PSA levels increased to the same level as pre- tion), 10 mice were randomly assigned to each of ARl + led antisense oligonucleotide (SCRB) or ARl + custirsen treatment groups. Custirsen (lOmg/kg/each dose) or SCRB (10mg/kg/each dose) was injected i.p. once daily for the first week and then three times per week. AR1 (lOmg/kg/each dose) was administered orally once daily (morning) 7 days per week for 8 to 12 weeks. Tumor volume was measured once per week.

Serum PSA was determined weekly. PSA doubling time (PSAdt) and velocity were calculated by the ope method (PSAt ~— PSAHHUKLX em). All animal procedures were performed according to the guidelines of the Canadian Council on Animal Care and appropriate institutional certification.

The combination of custirsen and ARl more potently suppressed LNCaP cell growth rates in a dose and time dependent manner compared to custirsen or AR1 monotherapy (Figures 1—8).

Surprisingly, PARP cleavage (Figure 15), sub GO/Gl apoptotic fraction (Figures 7 and 8) and repressed AKT phosphorylation (Figures 10 and 18) was most increased with combined therapy.

Additionally, sen acceleratedv AR degradation (Figures -19 and 22) and repressed AR transcriptional activity (Figures 20—22) in combination with_ ARl. In vivo, combined custirsen and ARl icantly delayed tion—resistant LNCaP tumor progression and PSA progression (Figures 26—29) compared to scrambled oligonucleotide control and ARl (p<0.05 and p<0.05 at 12 weeks, respectively).

Conclusions Custirsen combined with ARl down—regulated AR levels and ty and suppressed castration—resistant LNCaP cell growth in vitro and in Vivo, providing pre-clinical proof-of- principle as a promising approach for AR-targeting therapy in CRPC.

Example 2. Materials and Methods Prostate Cancer Cell Lines and Reagents LNCaP cells were kindly provided. by Dr. Leland. W.K. Chung (1992, MDACC, Houston Tx) and tested. and. authenticated. by whole—genome and. whole—transcriptome cing on na Genome Analyzer IIX platform in July 2009. LNCaP cells were maintained RPMI 1640 (Invitrogen Life logies, Inc.) mented with 5% fetal bovine serum and 2mmol/L L— glutamine. Cells were cultured. in a humidified. 5% COg/air atmosphere at 370C. Cycloheximide and MG—132 were purchased from Calbiochem, R1881 (Perkin-Elmer), AR1 (MDV-3100; Haoyuan Chemexpress Co., Limited). Antibodies: anti-GRP78, anti—CREBZ (ATF4), CLU C-l8, AR N-ZO, AR 441, PSA C-l9, Ubiquitin, pERK, B—tubulin and vinculin from Santa Cruz Biotechnology; anti— phospho-elFZa from Invitrogen Life Technologies; anti—ATF6 from Imgenex Corp; Atg3, LC3, pAkt/Akt, meOR/mTOR, pp7OS6K/p7OS6K, poly(ADP ribose)polymerase (PARP)form from Cell Signaling Technology; and anti—Vinculin and —Actin from Aldrich.

CLU siRNA and antisense treatment siRNAs were purchased from Dharmacon Research, Inc., using the siRNA sequence corresponding to the human CLU initiation site in exon 2 and a le control as previously described (Lamoureux et al., 2011). —generation antisense (custirsen) and scrambled (Sch) oligonucleotides with a 2’—O— (2-methoxy)ethyl modification were supplied by OncoGenex -43_ WO 23820 Pharmaceuticals. custirsen sequence (5'—CAGCAGCAGAGTCTTCATCAT— 3'; SEQ ID NO: 3) corresponds to the initiation site in exon II of human CLU. The Sch control sequence was 5'— CAGCGCTGACAACAGTTTCAT—3’ (SEQ ID NO: 44). Prostate cells were treated with siRNA or oligonucleotides, using protocols described previously (Lamoureux et a1., 2011).

Western blotting analysis and immunoprecipitation Total proteins were extracted using RIPA buffer (50mM Tris, pH 7.2, 1% NP-40, 0.1% deoxycholate, 0.1% SDS, 100mM NaCl, Roche complete protease inhibitor cocktail) and submitted to n blot as we described previously (Zoubeidi et al., 2007). For immunoprecipitation, total ns (500 ug) were pre—cleared with protein—G sepharose (Invitrogen Life Technologies) for 1 h at 4°C and immunoprecipitated with 2 ug anti—AR, or globulin G (IgG) as a control overnight at 4°C. The immune xes were recovered with protein—G sepharose for 2 h and then washed with radioimmunoprecipitation assay buffer (RIPA) at least , centrifuged, and submitted. to SDS— PAGE, followed by Western blotting.

Quantitative Reverse Transcription—PCR Total RNA was extracted from cultured cells after 48 hours of treatment using TRIzol reagent (Invitrogen Life Technologies, Inc.). Two ug of total RNA was reversed transcribed using the Transcriptor First Strand cDNA Synthesis Kit (Roche Applied e). Real time monitoring of PCR amplification of complementary DNA (cDNA) was performed using DNA primers (supplemental table) on ABI PRISM 7900 HT Sequence Detection System (applied Biosystems) with SYBR PCR Master Mix (Applied Biosystems). Target gene expression 5'-TACCAGCTCACCAAGCTCCT—3' (forward; SEQ ID NO: 45) or 5’-GCTTCACTGGGTGTGGAAAT-3' (reverse; SEQ ID NO: 46) targeting human AR, 5'— CACAGCCTGTTTCATCCTGA-S' rd; SEQ ID NO: 47) or 5'— AGGTCCATGACCTTCACAGC—B' (reverse; SEQ ID NO: 48) targeting human PSA, were normalized to b- actin levels using 5'— GGCACCACACCTTC-B' (forward; SEQ ID NO: 49) or 5'- AGCACTGTGTTGGCGTACAG—3' (reverse; SEQ ID NO: 50) as an internal rd, and the comparative cycle threshold (Ct) method was used to calculated relative quantification of target mRNAs. Each assay was performed in triplicate.

Immunofluorescence LNCaP cells were grown on coverslips and transfected with CLU siRNA or control. 48 hours post ection cells were treated, with lOuM. of ARI i 3. nM iRl88I for 6 'hours. After treatment, cells were fixed in ice-cold. methanol completed with 3% acetone for 10 min at —200C. Cells were the washed thrice with PBS and incubated with 0.2% Triton/PBS for 10 min, followed. by washing' and. 30 min blocking“ in 3% nonfat Inilk before the addition of antibody overnight to detect AR (1:250). Antigens were visualized, using anti-mouse antibody coupled with FITC (1:500; 30 min). Photomicrographs were taken at 20X magnification using Zeiss Axioplan II fluorescence microscope, followed by analysis with imaging software ern Eclipse, Empix Imaging, Inc.).

AR transcription activity LNCaP cells were seeded. at a density of 5XI04 in 12—well plates and. transfected. the following day‘ with. custirsen or SCRB. The next day cells were transfected with sen or SCRB together with ciferase (PSA-Luc) reporter (-6,100 to +12) and Renilla—luciferase plasmid using Lipofectin t (1.5uL per well; Invitrogen), as described previously (Sowery et al., 2008). After 24 h, the medium was replaced with RPMI (Invitrogen) containing 5% charcoal-stripped serum (CSS), mented with l nmol/L R1881 or ethanol vehicle and umol/L of ARl or DMSO for 48 h. Cells were harvested, and luciferase activity measured, as before (Sowery et al., 2008).

Reporter assays were normalized. to Renilla and luciferase activity expressed by Firefly to Renilla ratio in ary light units. All experiments were carried out in triplicate wells and ed five times using different preparations of plasmids.

Cell proliferation and cell cycle assays Cultured cells were transfected with CLU or SCR siRNA, custirsen or SCRB, and then treated with ARl or DMSO l 24h. after ection. After a time course exposure, cell growth was measured by crystal Violet assay as previously bed (Gleave et al., 2005). Detection and quantitation of apoptotic cell cycle population were analyzed by flow— cytometry (Beckman Coulter Epics Elite; Beckman, Inc.) based on 2N and 4N DNA content as previously described (Lamoureux et al., 2011). For CSS condition, LNCaP cells were plated in RPMI with 5% FBS switched to C88 at the next day, and treatment was started same as FBS condition. Each assay was done in triplicate three times.

Protein stability and degradation To assess the effect of combination treatment on AR protein stability, LNCaP cells treated. with custirsen or SCRB were changed 48 h later to RPMI + 5% serum containing 10 umol/L of cycloheximide and 10 umol/L of ARl incubated at 37 °C for 2 to 6 or 16 h and western blot was done using AR and vinculin WO 23820 antibodies. Degradation was tested in LNCaP cells by a 6—hour incubation with RPMI+5% FBS media containing 10 umol/L of MGl32 and 10 umol/L ARl 24 hours after siRNA or ABC transfection. Western blot was done using AR. and. vinculin antibodies.

Determination of increased efficacy of combination therapy Crystal violet assay was d to analyze cell growth inhibition for each single drug or their combination. LNCaP cells were treated. with. 10 nmol/L CLU siRNA. or SCR siRNA combined with tion dose of ARl and 500 nmol/L custirsen or SCRB as well. Next, cells were d for two consecutive days with dose escalating custirsen or oligofectamime only, and one day later treated with indicated concentration of ARl or DMSO for 48h. The data was inputted in CalcuSyn® software, and the dose effect curve drawn for each treatment to ate the ation index (CI) at several effective doses (CI=1; additive effect, CI<1; combination effect, CI>l; antagonistic effect).

Animal treatment Male athymic mice (Harlan Sprague—Dawley, Inc.) were injected s.c. with leO6 LNCaP cells. When tumors grow in 150mm3 and serum PSA was >50ng/ml, mice are castrated. Once tumors progressed to castrate resistance, mice were randomly assigned to ARl plus either 10 mg/kg custirsen or SCRB i.p. once daily for 7 days and. then three times per‘ week thereafter. Each mental group consisted of 13 mice. Simultaneously, mice were treated with ARl once daily p.o., lOmg/kg/each dose for 7 days per week. Tumor volume and serum PSA was Heasured as previously described (Sowery et al., 2008). All animal procedures were performed according to the guidelines of the Canadian Council on Animal Care. Each three mice xenografts were sacrificed at 7 days after start treatment and the rest were harvested the end of the study and snap—frozen in liquid nitrogen. Protein extraction was done by soliciting tumors in RIPA buffer with protease inhibitor and total cell lysate was used to assess AR and clusterin expression within the xenografts and referenced for B—tubulin as described in the section on Western blotting.

Statistical analysis All results are expressed as the average i SE. Two-tailed t— tests, y ANOVA or Wilcoxon matched—pairs tests were used for statistical is. Combination effects were calculated by CalcuSyn software. The differences between single treatment and combination treatment was analysis by Freidman test and done with. JMP version 4; *P<0.05, **P<0.0I, and. ***P<0.00I were considered significant.

Example 3. CLU is highly expressed in ARI ant cells and xenografts ARI is a novel anti-androgen which binds the AR LED and ts the growth of castration—resistant afts (Tran et al., 2009). Data from phase II and III trials show that ARI is active in both pre- and post—chemotherapy—treated patients and. decreases levels of PSA. and. ating" tumor cells (Scher et al., 2010) (Sher, GU—ASCO, 2012).

Unfortunately, like first line hormone therapies, CRPC—LNCaP afts evolved mechanisms of resistance after the addition of ARI to tion. CLU was found to be up—regulated in ARI resistant tumors compared to vehicle treated tumors by western blot (Fig. 41A, left panel) and immunohistochemistry (Fig. 41A right panel, Fig. 30A), suggesting that ARI treatment induces stress activated molecular chaperone CLU in CRPC tumors 2012/000609 similar‘ to that seen with. castration in castrate sensitive tumors. To facilitate study of mechanisms of ARl recurrence, different cell lines were created from xenograft tumors maintained under ARl treatment that were resistant to ARl, and found. that these ARl resistant cells also expressed. higher levels of CLU compared to CRPC tumors (Fig. 30B). These data indicate that increased CLU is associated with pment of the ARl recurrence phenotype.

Example 4. AR pathway inhibition induces and CLU Both ARl antisense ches were used to confirm whether CLU is induced by AR pathway inhibition. Compared to bicalutamide and androgen deprivation using CSS, ARl induces CLU in both a time— and dose~dependent , in parallel with reduced AR activation indicated by decreased PSA expression. To further te whether ARl ion of CLU is AR dependent, 2 different nse sequences ing the first exon in AR potently down-regulated AR in a dose-dependent and sequence— specific manner in LNCaP cells, in parallel with induction of CLU (Fig. 41C). Together these data suggest that AR pathway inhibition by androgen deprivation, AR LBD antagonism, or nse knockdown induces CLU, possibly as part of an adaptive stress response.

Clusterin expression is up—regulated by ARl treatment.

Clusterin expression is up-regulated in a time and dose dependent manner after ARl treatment. LNCaP Cells are treated for different durations and with different concentrations of ARl in RPMIl64O media with 5% FBS. Cells are harvested and performed for western blot analysis. Clusterin protein sion is up regulated in a time and dose dependent manner. Androgen depleted treatment enhances Clusterin expression, ally in AR1. LNCaP Cells are treated with 10 umol/L of Bicalutamide or AR1 for 48hrs in RPMIl64O media with % FBS or 5% CSS (charcoal striped serum; terone depleted media). Clusterin sion is strongly induced by anti-androgen treatment or CSS condition. Additionally, clusterin protein expression strongly increases in AR1 treatment compared to bicalutamide treatment in western blot analysis. The combination of ARl and custirsen is more effective at reducing te cancer cell proliferation than the combination of tamide and custirsen.

Example 5. ARI induces ER stress Whether AR1 induces ER stress with increase of CLU was evaluated since molecular chaperones like CLU are ant in regulating Inisfolded. protein. and. endoplasmic reticular (ER) stress responses d et al., 2007), and many anti-cancer agents are known to induce ER stress. ER stress activates a complex intracellular signaling pathway, called the unfolded protein response (UPR), which is ed to re—establish protein homeostasis (proteostasis) by inhibiting protein translation and. promoting' ER—associated. protein degradation via the ubiquitin-proteasome system (UPS). ARl is found to induce CLU expression itant with. up—regulation of ER stress markers such as GRP78, ATF4, IREl, CHOP and cleaved- ATF6, tent with ER stress and UPR activation.

Example 6. ARl—induced CLU is mediated by p90Rsk—YB—1 signalling pathway YB-l binds to CLU promoter leading to increased CLU expression after ER stress (Shiota et al., 2011). Since ARl can activate Akt and Erk signalling (Carver et al., 2011), it was postulated that AR1 mediated activation of Akt (Evdokimova et al., 2006) and Erk ford et al., 2008) pathways leads to o-activation and nuclear translocation of YB—l (Evdilomova et al., 2006), with up-regulation of CLU and inhibition of stress—induced apoptosis. Figure 42B confirms that ARl treatment ses Akt and p9ORsk phosphorylation, which was accompanied with increased phospho—YB—l levels (Fig. 42B). YB—l knockdown using siRNA in ation with ARl treatment abrogates ARl—induced CLU both at the n and mRNA levels (Fig. 42C) suggesting' that ARl—induced. CLU is mediated by YB-l.

Since YB—l can be phosphorylated by both Akt and p9ORsk (Evdilomova et al., 2006) (Stratford et al., 2008), LY294002 was used to inhibit Akt and SL0101 was used to inhibit p90Rsk to further define the predominant pathway mediating ARl induced up—regulation of CLU. Inhibition of Akt did not affect ARl induced up—regulation of CLU (Fig. 42D); in contrast, inhibition of p90Rsk using SL101 abrogates ARl-induced. CLU (Fig. 42E). Without wishing to be bound by any scientific theory, collectively these data indicate that the p90Rsk—YB—1 pathway is required for ARl induced CLU expression.

Example 7. The combination of CLU inhibition and ARI ses inhibition of LNCaP cell growth compared to CLU inhibition or ARl monotherapy.

Whether CLU knockdown potentiates the anti—cancer activity of ARl was evaluated, because R drugs (July et al., 2002) like ARl (Figs. 30 and 41) induce up-regulation of CLU and CLU functions as a or in treatment resistance (Zoubeidi et al., 2010b; Gleave et al., 2005). LNCaP cells were treated with custirsen and subsequently treated with indicated concentrations of ARl. Custirsen significantly enhanced ARl activity, reducing cell ity compared with control Sch plus ARl in both time- (Fig. 43A left panel) and dose— (Fig. 43A right panel) dependent s. To determine whether this effect was additive or a ation effect, the dose— dependent effects with constant ratio design and the CI values were calculated according to the Chou and Talalay median effect pal (Chou et al., 1984). Figure 6B shows the dosesresponse curve (combination or monotherapy with custirsen or ARl) along side the CI plots, indicating that the combination of sen with, ARl has enhanced. effects on tumor cell growth (Fig. 6C, right panel). The ation of custirsen and. ARl also had increased efficacy’ at reducing viability of AR positive castrate resistant C4~2 and custirsen—resistant cells compared to ARl or custirsen monotherapy, but not in AR negative PC3 cells.

Flow cytometric analysis indicates sen significantly increases (P < 0.001) ARl induced apoptosis (sub—Gl fraction) when ed with ARl (30%) compared with control Sch (15.2%), custirsen (20%), control Sch or ARl (18.3%) (Fig. 43C). In addition, combination sen plus ARl increases caspase—dependent apoptosis compared. with ARl or custirsen monotherapy, as shown by cleaved PARP and caspase—3 activity.

Collectively, these data indicate that the combination of custirsen and ARl induced apoptosis more than custirsen or ARl monotherapy.

Example 8. Clusterin knock down combined with ARl treatment mostly enhances cell growth inhibition and apoptosis in AR positive LNCaP cells.

LNCaP cells are seeded in 12—well culture plates in 5x104 cells per well with 5% FBS or 5% CSS containing RPMI medium.

The next day, cells are transfected with lOnmol/L of CLU siRNA WO 23820 or SCR siRNA control at once and also daily with 500 nmol/L of custirsen or SCRB control for 2 days. The next day post ect with siRNA or antisense oligo, LNCaP cells are treated with /L of ARl and cell growth assays are med on day 0, 1, 2, 3, 4 by crystal violet assay. (day of ART treatment defined as 100%). CLU knockdown + ARl ation treatment most significantly repress cell growth. pmol/L of ARl is combined with 10 nmol/L of CLU siRNA; lO umol/L of ART combined with 500 nmol/L of custirsen.

Combination ent enhances LNCaP apoptosis in flow cytometry analysis. Cells are treated with lOnmol/l; of CLU siRNA or SCR siRNA control at once and also daily with 500 nmol/L of custirsen or SCRB control for 2 days in 5% PBS containing RPMI medium. The next day post transfect with siRNA or antisense oligo, LNCaP cells are treated with lOumol/L of ARl and FACS analysis are performed after 48hrs treatment. The proportion of cells in sub—GO, GO-Gl, S, G2—M is ined by propidium iodide staining. Combination treatment increases Sub—GO/l apoptotic fraction apoptosis in LNCaP cells. p<0.01 in combination CLU siRNA with ART and p<0.001 in combination custirsen with ARl relative to oligofectamime and DMSO control. P value represents between treatment arms and their respective controls *p<0.05, **p<0.01, ***p<0.001 (Wilcoxon matched~pairs test).

Combination ent enhances apoptosis. LNCaP cells are pretreated with 10 umol/L of ARl for 48 h before treatment with CLU’ or SCR‘ siRNA. and. custirsen. or SCRB control. PARP cleavage expression levels are measured by Western blot. All experiments are repeated at least thrice.

Example 9. The combination, of custirsen ‘with. ARl ent shows increased efficacy compared to custirsen or ARl monotherapy.

Inhibition of growth is observed in LNCaP cells treated with CLU siRNA or sen combined with ARl in Vitro. Cells are transfected with lOnmol/L of CLU siRNA or SCR siRNA control at once and. also daily' withv 500 nmol/L of sen or SCRB control for 2 days in 5% FBS RPMI medium. The next day post transfect with siRNA. or antisense oligo, LNCaP cells are treated with various concentrations of ARl. Three days after treatment, cell viability is determined by crystal violet assay. Viable cell density' is normalized. to that of cells treated at DMSO control (ARl compound is dissolved in DMSO and adjusted. indicated. concentrations). The ation of sen with ARl shows increased efficacy at reducing cell viability compared to custirsen or ARl monotherapy. Data points are means of triplicate is. P value represents between treatment arms and their respective controls *p<0.05, **p<0.01 (Student’s t-test).

Cell growth inhibition is evaluated for each single drug or their combination by crystal violet assay. LNCaP cells are treated with variable concentration of ARl or custirsen. There is a significant difference between each single treatment and those combinations. P value is ated by Friedman test.

The data are input and calculated by CalcuSyn software®. r Combination index (CI) at several effective dose.

CI=1; additive effect, CI<l; combination effect, CI>l; nistic effect. These data indicate the combination effect at combination treatment.

W0 2012/123820 Example 10. AR and PSA sion in combination treatment.

AR protein expression decreases after CLU knockdown using custirsen combined with ARl. LNCaP Cells are ected with lOnmol/L of CLU siRNA or SCR siRNA control at once and also daily with 500 nmol/L of custirsen or SCRB l for 2 days in 5% FBS RPMI medium. The next day post transfect with siRNA or antisense oligo, LNCaP cells are d with /L of ARl. 48hrs later, cells are ted for protein and mRNA.

The n expression is analyzed by western blot. CLU knockdown combined with ART treatment has enhanced potency in decreasing' AR expression compared to monotherapy. AR expression is strongly repressed by CLU knockdown with ARl.

Cells are treated. with. lOnmol/l: of CLU siRNA or SCR siRNA combined with lOpmol/L of ARl or bicalutamide. AR expression is detected by western blot. Combination treatment does not affect AR mRNA level. mRNA expression is analyzed by quantitative RT—PCR, AR and PSA levels are normalized to levels of B-actin mRNA and expressed as mean i SE. **P<0.0l ***p<0.001 (Wilcoxon matched—pairs test). “OTR” means cells treated with oligofectamime only. OTR and DMSO d cells were defined as 1009.

Example 11. Combination ARI plus custirsen has increased efficacy in delaying CRPC LNCaP tumor growth The in vivo effects of co—targeting‘ the AR and. the stress response using‘ ed custirsen with ARl were evaluated.

Male nude mice bearing LNCaP xenografts were castrated when serum PSA reached 75ng/ml and followed until serum PSA and tumor growth rates increased. back to pre—castrate levels, indicating progression to castration resistance. Mice were then randomly assigned for treatment with ARl plus either control Sch (n 10) or custirsen (n=lO). At baseline, mean LNCaP tumor volume and serum PSA levels were similar in both groups. Custirsen significantly enhanced the mor effect of ARl, reducing mean tumor volume from 1600 mm3 to 650 mm3 by 12 weeks (**; pS0.05), compared to control Sch (Fig. 44A).

Overall survival (defined as asia for tumour volume exceeding 10% of body weight) was significantly prolonged with combined ARl + custirsen compared with ARl + Sch control (90% vs 30% at week 16, tively; *; pS0.05). Serum PSA levels were also significantly lower (~4—folds) (Fig. 44C), and PSA doubling time is significantly prolonged (*, p<0.05) in the custirsen + ARl group (***, p<0.001) ed with ARl control group. To evaluate the pharmacodynamics effects of combination treatment on target n levels, western blot analysis from tumour tissue (3 animals each) was performed for AR, PSA and CLU. Fig. 44D illustrates that AR and CLU expression levels were reduced in combination-treatment tumour tissue compared to ARl controls. Collectively, these data demonstrate that co—targeting the AR and the resultant CLU-regulated stress response potentiates the effects of ARl in a human CRPC xenograft model.

The efficacy of sen and ARl combination y is enhanced compared to ARl or custirsen erapy in a CRPC xenograft model. Figure 44A~B shows the effect on tumor volume and serum PSA level by combination treatment.

Example 12. Combination ARl plus custirsen has increased efficacy in CRPC xenograft model.

LNCaP cells are inoculated s.c. into athymic nude mice. When xenografts grow to ~500 mm3, or PSA >50 ng/ml mice are castrated. Treatment is started when PSA levels increased to pre—castration . Custirsen or SCRB are injected i.p. —56- PCT/11320121000609 once daily for 1 week and then 3 times/week fter. ARl is administrated once daily. Total LNCaP xenograft proteins are extracted in. RIPA, buffer after custirsen. or SCRB treatment combined with ARl. (three mice per group) and Western blots are done with AR, PSA, and CLU antibodies; vinculin is used as a loading control. ulin ratio is calculated. ation ARl plus sen has increased efficacy at prolonging survival in the CRPC xenograft model.

Example 13. Combination .ARl plus CLU silencing reduces AR nuclear translocation and transcriptional ty more effectively than ARl or CLU silencing monotherapy.

The in vivo study in Figure 44 shows that custirsen in combination with. ARl induces rapid. decrease in PSA, before changes in tumor volume became nt; in addition, AR protein levels appeared lower in the combination treated tumors compared to AR1 alone treated tumors, suggesting that CLU own might iate AR targeting and modulate AR signalling pathway. The effects of combination treatment on androgen—induced, AR—mediated gene activation were evaluated.

LNCaP cells were treated with ARl or custirsen alone or in combination and evaluated for changes in R1881 stimulated PSA transactivation (Fig. 45A). As expected, ARl reduced R1881 d AR transcriptional activity, as measured by PSA luciferase transactivation assay, by 95%; interestingly custirsen also reduced AR activity by 90%, and this effect was enhanced in combination with ARl suggesting that CLU knockdown potentiates ARl inhibition of AR activity. To define how CLU can affect AR riptional activity, the effect of CLU knockdown i ARl on ligand—induced AR nuclear translocation was evaluated. As expected, while AR nuclear translocation was decreased by AR1, CLU knockdown in combination with ARl maximally inhibited R1881—induced AR nuclear translocation (Fig 45B). This co-targeting inhibitory effect was also confirmed by fractionation assay showing that targeting CLU in combination with ARl inhibits Rl88l-induced nuclear AR levels (Fig. 45C).

Example 14. CLU knockdown combined with ARl treatment rates AR degradation via the proteasome pathway.

To investigate the fate of AR after combination treatment, the effect of CLU knockdown combined with ARl on AR expression was evaluated both at the protein and mRNA levels. CLU ing using siRNA (Fig. 46 A right upper panel) or custirsen (Fig. 46 A left upper panel) resulted in decreased AR protein, but not mRNA levels (Fig. 46 lower panel) only in combination with ARl, suggesting that CLU knockdown in combination with ARl may affect AR stability. AR n stability was then evaluated using eximide, which inhibits protein synthesis. AR protein levels decreased significantly with rapid degradation after custirsen—induced CLU knockdown ed with ARl (Fig. 46B), suggesting that CLU knockdown leads to AR instability when complexed with ARl.

AR forms a dimer x with Hsp90 to provide stability for ligand—unbound. AR. Indeed, without Hsp90 g, the unfolded n will be recognized and degraded by the ubiquitin-proteasome system (Solit et al., 2003; Zoubeidi et al., 2010c). Whether ARl affects AR binding- to Hsp90, and subsequent effects if combined with CLU silencing was first evaluated. ARl treatment actually increases AR-Hsp90 interactions, consistent with prior reports that ARl sequesters AR in the cytoplasm. Interestingly, CLU knockdown in combination with ARl decreases the ation between AR ~58— W0 23820 and Hsp90, as shown in Figure 46C. Without wishing to be bound by any scientific theory, these data are consistent with a view that ARl—AR—Hsp90 complex becomes more vulnerable to degradation under conditions of CLU silencing. To assess whether~ AR degradation. under these conditions involves the ubiquitin—proteasome system, levels of ubiquitinated AR were measured under conditions of mono- or after combination therapy, and as shown in Figure 46D, AR ubiquitination levels were highest under co—targeted combination conditions. AR protein levels were next evaluated in the presence or e of proteasome inhibitor (MG132) to characterize role of proteasome and MG132 was found. to te AR. degradation under conditions of CLU knockdown plus ARl, implicating* AR degradation via the proteasome (Fig. 46E). t wishing to be bound by any scientific theory, taken together these data suggest CLU knockdown accelerates AR ation via a some mediated pathway preferentially when the AR is bound to ARl.

Example 15. AR degradation rates are accelerated by ation treatment.

Combination treatment rapidly decreases AR expression. LNCaP cells are treated with 500 nmol/L of custirsen or SCRB control and then treated, with. 10 umol/L of ARl and. 10 umol/L of cycloheximide various time periods. DMSO is used as control.

AR protein levels are measured by Western blot analysis. CLU knockdown combined with ARl accelerates proteasomal degradation of AR. LNCaP cells are treated with CLU siRNA or SCR siRNA and custirsen or SCRB control, and then treated with pmol/L of ARl and 10 umol/L MG-132 for 6h. DMSO is used as control. AR protein levels are measured by n blot analysis.

W0 2012/123820 Example 16. Combination treatment effects AR ubiquitination.

LNCaP cells are treated with 10 nmol/L of CLU siRNA or SCR siRNA control in the presence of FBS and then d with 10 umol/L of ARl and 10 umol/L of . Immunoprecipitation is done using anti—AR antibody , and Western blot analysis is done using anti—AR antibodies (441) or anti—Ubiquitin antibodies. Input is blotted with AR (N-ZO) antibody. Without wishing to be bound. by any scientific , combination treatment facilitates proteasomal degradation of AR via ubiquitination of AR.

Example 17. CLU knockdown decreases levels of molecular co— chaperones involved in AR stability Without wishing to be bound by any scientific theory, the data herein tes that ARl monotherapy sequesters AR—Hsp90 complexes in the cytoplasm; however when combined. with CLU knockdown the AR—Hsp90~ARl heterocomplex becomes destabilized, leading to AR ubiquitination and ation, and reduced AR nuclear transport and. activity. One explanation is the CLU inhibition may lower Hsp90 levels through its affects on HSF-l regulation (Lamoureax et al. 2011); however ation therapy' did. not significantly* lower Hsp90 levels, and. data illustrated in Figure 42 implicates YB-l as the key stress- activated transcription factor mediating ARl increases in CLU.

Since Hsp90 functions in cooperation with co—chaperones to confer ity of client proteins, an unbiased approach was initially used to identify Hsp9O perone affect by CLU expression. The gene profiling analysis from LNCaP cells and PC—B treated with l and CLU siRNA disclosed herein shows that CLU expression correlated. with the Hsp90 co-chaperone FKBP52 (Hsp56). Western blotting was used to confirm that CLU knockdown. reduces FKBP52, but not FKBPSl or‘ Hsp90, protein levels (Fig. 47A). To ascertain. the role of FKBP52 in. AR ity under conditions of ARl treatment and CLU silencing, FKBP52 was overexpressed after CLU knockdown and AR expression was evaluated. Figure 47B shows that FKBP52 rescues AR from degradation induced by CLU knockdown and ARl treatment. FKBP52 overexpression also partially restores PSA expression, indicating increased AR activity when FKBP52 levels are ed under conditions of CLU knockdown. These data suggest that CLU knockdown in combination with ARl induces AR degradation by affecting FKBP52 levels and the stability of the AR-co-chaperone complex.

To further define how CLU regulates FKBP52 levels under conditions of ARl induced stress, public databases were mined and provided information ting that YB—l binds to FKBP52 with high stringency of 12 in ChIP on ChIP is. Western blotting confirmed that YB—l knockdown ses FKBP52 expression levels (Fig. 47C). ARl treatment activates a stress response involving' YB—l transactivation. of CLU} as well as increased Akt and p90rsk activity (Fig 42). Since YB~l knockdown decreases both CLU and FKBP52 levels, and CLU can also enhance p—AKT activity, how CLU knockdown affects interactivity between YB-l, AKT and p90rsk to affect FKBP52 levels under conditions of ARl treatment was igated next. Interestingly, similar to previous s that CLU can enhance AKT phosphorylation, CLU knockdown was found to also abrogate ARl induced phosphorylation of YB—l and p9ORsk (Fig. 47D). Without wishing to be bound by any scientific theory, since the p9ORsk—YB-l pathway is the key regulator for ARl induced CLU sion (Figure 42), collectively these data identify an ARl treatment—induced feed forward loop involving pYB—l, p90rsk, CLU, and the AR co—chaperone FKBPSZ for AR stability, nuclear translocation and activation.

Example 18. ation treatment inhibits Akt/mTOR signalling pathway.

ARl activates phosphorylatior of Akt and ERK. LNCaP cells are treated with ARl in media with 5% PBS at various time periods and doses. Western blot analysis is done using phospho Akt, phospho ERK, Akt and ERK antibodies. CLU knockdown attenuates Akt/mTOR signalling pathway through inhibition of phospho Akt activation by ARl treatment. LNCaP cells are treated with 10 nmol/L CLU siRNA or SCR siRhA l in the ce of PBS and then treated with 10 umol/L of ARl. After 48h treatment, n blot analysis is done using phospho Akt, phospho ERK, phospho mTOR, phospho P7OS6K, Akt, ERK, mTOR and P7OS6K antibodies.

Example 19. Possible explanation of combination effect n clusterin knockdown and ARl for AR ve state.

Androgen binding to AR leads to rapid translocation from cytoplasm to nucleus and it leads to enhance tion of AR— regulated genes. Clusterin up-regulates the AKT/mTOR pathway and it leads to cell survival, cell proliferation and cell growth. Custirsen induced. clusterin knockdown represses AKT phosphorylation and. attenuates androgen transportation from cell surface via repressing megalin expression. ARl ly binds to AR and inhibits its translocation to nucleus. Without wishing to be bound by any scientific theory, these results lead to accelerate AR proteasomal degradation and down— regulated mTOR signalling pathway. —62- Example 20. Clusterin knock down combined with ARl treatment mostly enhances cell growth inhibition and apoptosis in C4-2 cells, but does not have a combination effect in AR negative PC—3 cells.

C4—2 cell growth is evaluated upon combination treatment. C4-2 cells are seeded in 12~well culture plates in 3x104 cells per well with 5% PBS or 5% CSS containing RPMI medium. The next day, cells are transfected with lOnmol/L of CLU siRNA or SCR siRNA control. The next day post ect with siRNA, C4-2 cells are treated with 10 umol/L of ARl and cell growth assays were performed on day 0, l, 2, 3, 4 by crystal violet assay. (day of ARl treatment defined as 100%). CLU own and ARl combination treatment represses cell growth most significantly. PC—3 cell growth is evaluated upon combination treatment. PC—3 cells are seeded in 12—well culture plates in 3x104 cells per well with 5% PBS containing DMEM medium. The next day, cells are transfected with lOnmol/L of CLU siRNA or SCR siRNA l at once and also daily with 500 nmol/L of custirsen or SCRB control for 2 days. The next day‘ post transfect with siRNA or antisense oligo, PC—3 cells are treated. with. 10 nmol/L of ARl and cell growth assays are performed on day 0, l, 2, 3 by crystal violet assay. (day of ARl treatment defined as 100%). Combination treatment enhances LNCaP apoptosis in flow cytometry analysis. Cells are treated with /L of CLU siRNA or SCR siRNA control at once and also daily with 500 nmol/L of custirsen or SCRB l for 2 days in 5% FBS containing RPM; . The next day' post transfect with siRNA or antisense oligo, LNCaP cells are treated with lOumol/L of ARl and FACS analysis were performed after 48hrs treatment. Proportion of cells in sub—GO, GO—Gl, S, GZ—M was determined by propidium iodide staining.

Combination ent increases Sub-GO/l tic fraction ~63- apoptosis in LNCaP cells. lCa: ed with CLU siRNA, le: combined with custirsen.

Example 21. Clusterin and AR mRNA expression is up—regulated in a time and dose dependent manner after ARI treatment.

LNCaP Cells are treated with deferent time and different concentration of AR1 in RPM1164O media with 5% FBS. AR1 is treated at various concentrations and exposure times. Cells are harvested and ed for mRNA level by quantitative RT— PCR. AR and CLU levels are normalized to levels of B—actin mRNA and expressed as mean f SD. ARl exposure time of O h and dose of Onmol/L defined as 100%. *P<0.05 **P<0.01 ***p<0.001 (Wilcoxon matched-pairs test).

AR protein expression decreases after CLU knockdown combined with, ARl in both androgen depleted. and. androgen stimulated cells. LNCaP Cells are transfected with 10nmol/L of CLU siRNA or SCR siRNA control in 5% CSS with or without 1 nmol/L of R1881 ning RPMI . The next day post transfect with siRNA, LNCaP cells are treated with /L of AR1. 48hrs later, cells are harvested for protein. The protein sion is analyzed by Western blot. CLU knockdown combined with AR1 treatment decreases AR expression with greater efficacy than CLU knockdown alone or ARl monotherapy.

Discussion In prostate cancer, the androgen receptor (AR) continues to drive te ant progression after castration. While new AR pathway inhibitors like ARl prolong al in CRPC, resistance rapidly develops and is often associated with re~ activation of AR signalling and induction of the cytoprotective one, clusterin (CLU). Since adaptive stress pathways ted. by treatment can facilitate development of ed treatment resistance, co-targeting the stress response activated by AR inhibition, and mediated through CLU, may create conditional lethality and e outcomes. The data herein show that co—targeted the AR and stress—induced CLU by combining ARl with custirsen, and defined mechanisms of combination activity using the castrate— resistant LNCaP model.

ARl induced markers of ER stress markers and chaperone proteins, including CLU, as well as the AKT and MAPK signalosome. This stress response was coordinated by a feed forward loop involving p-YB—l, p90rsk, and CLU. Combination CLU knockdown plus ARl suppressed LNCaP cell growth rates by enhancing apoptotic rates over that seen with ARI or custirsen monotherapy. In vivo, combined custirsen + ARl significantly delayed castration—resistant LNCaP tumor progression and PSA progression. istically, ARl d AR cross talk activation of AKT and MAPK pathways was repressed with combined therapy. Interestingly, CLU knockdown also accelerated. AR. degradation and repressed. AR transcriptional activity when combined with ARl, through mechanisms involving decreased HSF—l and YB—l regulated expression of AR co— chaperones FKBPSZ.

Co—targeting adaptive stress ys activated by AR y inhibitors, and mediated through CLU, creates conditional lethality and es mechanistic and inical proof—of— principle to guide biologically rational combinatorial clinical trial design.

Prostate cancer is the most common solid malignancy and second leading cause of cancer deaths among males in Western countries (Siegel et al., 2011). While early-stage disease is treated with curative surgery or radiotherapy, the mainstay of ent for locally ed, recurrent or metastatic prostate cancer is androgen ablation therapy, which reduces serum testosterone to castrate levels and suppresses androgen receptor (AR) activity. Despite high initial response rates after androgen on, progression to castrate resistant prostate cancer (CRPC) occurs within 3 years (Gleave et al., 2001; vsky et al., 2000; berg et al., 1999; Goldenberg et al., 1996; Gleave et al., 1998; Bruchovsky et al., 2006). Over 80% of CRPC specimens express the AR and androgen—responsive genes (Chen et al., 2004), indicating that the AR axis remains activate despite castration. Hence, the AR is a key driver of CRPC, and is supported by treatment— activated growth factor signalling ys (Miyake et al., 2000), survival genes (Miyake et al., 1999), and cytoprotective chaperone networks (Rocchi et al., 2004).

Docetaxel chemotherapy (Petrylak et al., 2004) was the first therapy to prolong survival in CRPC, stratifying the treatment landscape into pre— and post—chemotherapy states. More recently, two new AR pathway tors, the CYP17 inhibitor abiraterone (de Bono et al., 2011) and the AR antagonist ARl (Tran et al., 2009), have produced promising survival gains and are rapidly changing the CRPC landscape. Despite —66- W0 2012/123820 significant responses (Tran et al., 2009; Harris et al., 2009; Scher et al., 2010), abiraterone and ARl activate redundant survival pathways that vely drive treatment resistance and recurrent CRPC progression. Realization of the full potential of these novel AR pathway inhibitors will require characterization of these stress—activated survival responses, and rational combinatorial co—targeting strategies ed to abrogate them.

Molecular chaperones play central roles in stress responses by maintaining protein homeostasis and playing prominent roles in signalling and transcriptional regulatory networks. Clusterin (CLU) is a stress~activated. chaperone originally cloned as “testosterone—repressed) prostate message 2” (TRPM—Z) (Montpetit et al., 1986) from post—castration regressing rat te, but was subsequently defined as a stress-activated and apoptosis-associated, rather than an androgen—repressed, gene (Cochrane et al., 2007). CLU is transcriptionally regulated by HSFl (Lamoureux et al., 2011) and YB—l (Shiota et al., 2011), ting —induced sis by suppressing protein ation (Poon et al., 2002), p53—activating stress signals (Trougakos et al., 2009), and conformationally—altered Bax (Zhang et al., 2005; Trougakos et al., 2009) while enhancing Akt phosphorylation (Ammar et al., 2008) and trans— activation of NF-KB and HSF—l (Lamoureux et al., 2011; Shiota et al., 2011; Poon et al., 2002; Trougakos et al., 2009; Zhang et al., 2005; Ammar et al., 2008; Zoubeidi et al., . CLU is sed in many human cancers (Yom et al., 2009; Kruger et al., 2007; Zhang et al., 2006), including prostate, where it increases following castration and to become highly expressed in CRPC (July‘ et al., 2002). CLU’ over-expression confers treatment resistance (Miyake et al., 2000), while CLU -67— tion potentiates activity of most anti-cancer therapies in many preclinical models (Miyake et al., 2005; Sowery et al., 2008; Gleave et al., 2005; Zoubeidi et al., 2010b). The CLU inhibitor, OGX—Oll (custirsen, OncoGenex Pharmaceuticals), is currently in Phase III trials after a randomized phase II study in CRPC reported 7 Hwnth gain in overall survival and 50% reduced death rate (HR=O.50) when combined with docetaxel chemotherapy (Chi et al., 2010).

Since CLU’ is induced. by treatment stress, including castration, and functions as an important mediator of the stress response, the esis herein that ARl treatment induces the stress response and CLU, and that co—targeting the AR and. stress—response pathways mediated‘ by‘ CLU’ may create conditional lethality and improve cancer control was tested.

The data described herein set out to correlate ARI treatment stress and resistance with CLU induction, identify ys ting CLU activation, and define mechanisms by which CLU inhibition iates anti~AR therapy in CRPC.

Many strategies used to kill cancer cells induce stress— and redundant survival responses that promote survival and emergence of treatment resistance, which. is the underlying basis for' most ‘ . This therapeutic resistance s from. a Darwinian interplay' of innate and adaptive survival pathways activated by selective pressures of treatment. In prostate cancer, androgen ablation induces tumor cell sis and clinical responses in Hmst patients but also triggers ssion within 2—3 years to castration resistant prostate cancer (CRPC) (Gleave et al., 2001; Bruchovsky et al., 2000; Goldenberg et al., 1999; Goldenberg et al., 1996; Gleave et al., 1998). Experimentally, CRPC W0 2012/123820 progression is attributedl to re—activation of the AR axis (Miyake et al., 2000; Miyake et al., 1999) supported by growth factor (Miyake et al., 2000; Culig et al., 2004; Craft et al., 1999) and survival gene (Miyake et al., 1999; Gleave et al., 1999; Miayake et al., 2000; Rocchi et al., 2004; Miyake et al., 2000) networks. Recently new AR pathway inhibitors like abiraterone and ARl (Rocchi et al., 2004) have been shown to prolong survival and ally validate the AR as the main driver of CRPC (Miyake et al., 2000; Miyake et al., 1999).

Not all patients respond to these inhibitors, and resistance develops in many initial responders (Petrylak et al., 2004); moreover, disease progression frequently correlates with a rising PSA level, indicating continued AR ling and highlighting need for onal therapies targeting the lar basis of treatment resistance fill CRPC. Defining interactions between the AR and redundant survival pathways will build new combinatorial gies that control progression and improve outcomes.

Persistent AR signalling in CRPC is ated to occur via AR amplification and mutations that increase sensitivity to low levels of BET and other steroids (Miyake et al., 2000; Miyake et al., 1999; Zoubeidi et al., 2007), or AR splice variants that drive constitutively active truncated receptors lacking a LED (Nizard et al., 2007; Carver et al., 2011; Evdokimova et al., 2006). Other AR-related, mechanisms include altered levels of AR vators or co chaperones (hsp27), and AR phosphorylation via activated src or tyrosine kinase receptors like EGFR (Chi et al., 2010). Another more dynamic mechanism involves reciprocal ck regulation n AR and PIBK pathways whereby AR inhibition activates AKT signaling by reducing levels of the AKT phosphatase PHLPP, and PIBK inhibition activates AR signaling by relieving feedback inhibition of HER kinases; inhibition of one activates the other, thereby enhancing survival. These istic insights are guiding design of combinatorial regimens co-targeting the AR. pathway with inhibitors against histone deacetylase (de Bono et al., 2011), src, ART, and. AR chaperone heat-shock proteins (Hsp)—90 and Hsp27.

Inhibiting the stress se activated by AR pathway inhibitors is another combinatorial co—targeting strategy.

Many anti—cancer agents induce ER stress (Rutkowski et al., 2007), which activates a complex intracellular signaling pathway, termed the unfolded protein response (UPR), tailored to reestablish protein homeostasis by inhibiting protein translation and stimulating the ubiquitin—proteasome system (UPS) to enhance ER-associated protein degradation (BRAD) (Harding et al., 2002). Chaperones like CLU are key ors of ER stress responses. AR. pathway tion is known to induce ER stress and CLU with reciprocal pathway activation of AKT, which are all implicated in castration ance.

Consistent with these prior s, the data herein show that ARl induces ER stress and the UPR, and go on to define feed— forward. links between stress—induced YB—l activity to CLU activation in parallel with enhanced AKT and MARK signaling, which collectively support AR stability and ty under ARl treatment conditions. YB—l and CLU are both stress—activated survival chaperone proteins onally associated with anti— cancer treatment resistance (Poon et al., 2002) (Zoubeidi et al., 2007). Under stress conditions, YB-l is phospho-activated by AKT (Evdokimova et al., 2006) and p90RSK e et al., 2005), stimulating its nuclear translocation and binding to target promoters. CLU is transcribed by, and acts as, a W0 2012/123820 critical downstream mediator of stress—induced YB-l activity and paclitaxel resistance (Shiota). YB-l can also function as an mRNA chaperone protein to regulate translation of certain stress-associated transcripts (Law et al., 2010; Evdokimova et al., 2009). Using YBl RNA—1P ized to macroarrays with different platform technologies, YB: was found to bind to CLU mRNA. The data disclosed herein show that YBl binds preferentially to CLU mRNA after ARl induced ER , and found that YBl is associated with CLU—mRNA in different polysomal fraction. Since polysomal fractions represent translationally active mRNAs that are bound by ribosomes or other elements of the translational machinery, and post— polysomal mRNAs are me—depleted and hence translationally inactive ; Evdokimova et al., 2009; Evdokimova et al., 2006a), CLU mRNA will be amplified from these fractions. These data indicate that YB-l mediates not only transcriptional, but also ational, induction of CLU in response to ARl induced ER stress.

CLU is a stress—activated molecular chaperone closely linked to treatment resistance and cancer progression (Miyake et al., 2000; Gleave and Miyake, 2005; Trougakos and Gonos, 2009b), where its overexpression confers broad—spectrum treatment resistance (Tran et al., 2009; Yom et al., 2009). Similar to castration and other treatment ors, ARl increases CLU expression ; moreover, CLU levels are higher in A21 ant tumors, as they are in CRPC compared to castrate naive cancers. CLU is not only transcriptionally regulated by HSF~1, but also enhances HSF-l-mediated transcriptional activity in a orward manner (Lamoureax et al., 2011).

CLU is also activated by prosurvival pathways including the AR and downstream of IL—6 (via JAR/stat) and IGF-lR (via Src—MEK— W0 2012/123820 ERK—Erg—l) signalling pathways. CLU suppresses stress~induced apoptosis by inhibiting protein aggregation, p53-activating stress signals, and conformationally-altered. Bax (Zhang et al., 2005; Trougakos et al., 2009) while ing Akt orylation (Sowery et al., 2008; Chou et al., 1984) and trans—activation of NF—KB and HSF-l.

This —activated anti—apoptotic function for CLU results in broad-spectrunx resistance to many“ anti-cancer~ therapies, and identifies it as a potential anti—cancer target. A CLU antisense inhibitor, custirsen, enhances cancer cell death in combination with therapeutic stressors in many nical cancer models. Indeed, combination docetaxel plus custirsen phase III clinical trials are underway in CRPC after randomized Phase II studies reported a significant survival benefit when sen was added to docetaxel (Zoubeidi et al., 2010b; Culig et al., 2004). While CLU inhibition has been reported to enhance castration and delay time to CRPC in androgen—dependent xenografts, the pure AR antagonist ARl now enables investigation of effects of AR pathway inhibition and CLU in treatment response in vitro and in vivo in CRPC models.

The data disclosed. herein established. that CLU’ was induced after ARl and AR knockdown in ARl—sensitive and resistant LNCaP cells, tively, and that CLU remained highly expressed. in most ARl ant LNCaP xenografts and cell lines. Co-targeting the AR and CLU using ARl plus custirsen enhanced apoptotic rates over monotherapy. istically, ARl induced cross talk activation of ART and MAPK pathways was repressed with combined therapy. Unexpectedly, we found that AR ubiquitination and proteasome-mediated ation rates were accelerated. when ARl was combined. with. CLU knockdown.

While ARl alone did. not alter AR stability, when CLU was WO 23820 inhibited, stress—activation. of YB—l and MAPK was blunted, resulting in decreased. YB-l activated expression of AR co- chaperones Hsp56 (FKBP52) and Hsp90, which led to ubiquitination and. proteasomal degradation. of the AR, sing' AR. transcriptional activity' beyond. that observed with AR1 monotherapy, and even in ARl resistant cell lines.

These results highlight a role for CLU in supporting' YB—l mediated sion of other molecular chaperones under context dependent stress ions, similar to its ability to enhance HSF-l—mediated transactivation of Hsp70 and Hsp27 after Hsp90 inhibition (Lamoureax et al., 2011). In addition to CLU, HSF—l and YB—l orchestrate expression of other molecular chaperones involved in ses of folding, trafficking, and riptional activation of the AR and other steroid receptors. In the absence of ligand, AR is inately cytoplasmic, maintained in an inactive, but highly responsive state by a large dynamic heterocomplex composed. of Hsp90 and. Hsp70, and. co-chaperones like Hsp56.

These Hsp AR co—chaperones play important roles in AR stability and activation. g—Flynn et al., 2005; Yang et al., 2006). Ligand binding leads to a conformational change in the AR and dissociation from the large Hsp complex to associate with Hsp27 for nuclear transport and transcriptional activation of target genes (Zoubeidi et al., 2006; Abdul et al., 2001). Compared to the first generation. AR. antagonist bicalutamide, which does not inhibit AR nuclear transport, we show that und AR remains cytoplasmic and complexed with its Hsp chaperones, Hsp90 and FKBP52. This cytoplasmic confinement of AR. complexed. with. its Hsp co—chaperones may increase its susceptibility to degradation under conditions of ER stress and chaperone suppression.

PCT/IBZOlZ/000609 Without g to be bound by any scientific theory, the data herein identifies another mechanimn by which CLU inhibition potentiates anti-AR therapy, via suppression of MAPK and Akt signalling pathways activated after AR y inhibition. The data herein m. previous reports that ARl induces Akt phosphorylation, and also show that MAPK and p90rsk are activated by ARl to mediate YB—l phosphorylation. The results herein demonstrate that CLU knock down combined with ARl abrogates both Akt and p90rsk activation.

Without g to be bound by any scientific theory, the data herein define a stress—induced. feed-forward loop ing ARl—induced YB—l transactivation of CLU, with CLU facilitating pro—survival ART and p90rsk signalling, phospho-activation of YB—l, and expression of AR co-chaperones that stabilize the AR under conditions of ARl treatment. Co-targeting adaptive stress pathways ted by AR pathway inhibitors, and mediated through CLU, potentiate anti—AR activity by decreasing AR expression levels and activity, as well as ctivation of Akt and MAPK signaling ys induced by ARl.

These results provide mechanistic and pre-clinical proof—of— principle to support combinatorial clinical s with ARl and custirsen.

Aspects of the present invention relate to the unexpected discovery that an ucleotide targeting clusterin expression such as custirsen, together with an AR antagonist as a combination is more potent than a monotherapy of either agent for ent of prostate cancer. This increased efficacy is in addition to increased cancer cell death, and includes reduced proliferation of the cancer cells, reduced W0 2012/123820 translocation of AR from the cytoplasm to the nucleus, d riptional activity of AR, increased PARP cleavage, reduced AKT phosphorylation, reduced ERK phosphorylation, and increased. AR. protein degradation. Figure 30 shows that ARl resistant prostate cancer tumors have increased clusterin expression. Without wishing' to be bound. by' any scientific theory, the data herein may be reflecting that the resistance of these tumors to ARl may‘ be due to increased. clusterin expression, and therefore, decreasing clusterin expression increases the ivity of ARl ant tumors to ARl treatment. Thus, ARl resistant prostate cancer cells are ized to ARl by concomitant treatment with sen.

ARl s autophagy in prostate cancer cells (Fig. 38), and clusterin silencing can inhibit ER stress—induced autophagy.

Autophagy is ea well conserved lysosomal degradation pathway for intra—cellular ion that can confer stress tolerance and sustain cell viability under adverse conditions. Without g to be bound by any scientific theory, it is possible that sed autophagy following ARl treatment may enhance prostate cancer cell survival, and. inhibition of clusterin expression inhibits this increased autophagy, thereby resulting in reduced. cancer cell survival and. enhanced. ARl activity.

Without wishing to be bound by any scientific theory, decreased clusterin expression may enhance the activity of ARl by decreasing AR stability via suppression of HSF—l mediated regulation of AR co-chaperones such as FKBP52 and Hsp27.

Without wishing to be bound by any scientific theory, decreased clusterin expression may enhance the activity of ARl 320121000609 by sing the induction of AKT levels and/or phosphorylation ing ARl treatment.

ARl monotherapy is able to treat castration—resistant prostate cancer in humans; r, custirsen monotherapy has not been shown to inhibit the progression of prostate cancer after it has progressed to androgen—independence in any model .

It is therefore surprising that the combination treatment of ARl and custirsen would be more potent than treatment with AR: alone. Furthermore, ARl and custirsen combination therapy is surprisingly potent, and is able to halt prostate cancer cell growth in vitro, whereas cells receiving either agent alone erate by over 200% over a period of four days (Fig. 2B).

Surprisingly, also, the combination of custirsen and ARl is able to reduce AR. protein expression. by over 80%, whereas sen alone has no effect, and ARl alone reduces expression by only about 40% (Figure 17). Finally, the combination of custirsen and ARl increases the survival of treated mice afflicted with castration—resistant prostate cancer to about 90% at 16 weeks from the start of treatment, as compared to about 40% for ARl alone.

Additionally, the combination of ARl and, custirsen. is more effective at reducing tumor growth in mammals than the combination of bicalutamide and custirsen. The combination of ARl and custirsen is more effective at reducing tumor growth in mammals than the combination of flutamide and custirsen.

The combination of ARl and, custirsen, is more effective at reducing cancer cell proliferation than the combination of bicalutamide and custirsen. The combination of ARl and custirsen is more effective at reducing cancer cell proliferation than the combination of flutamide and custirsen.

The combination of ARI and custirsen is more effective at increasing cancer cell apoptosis than the ation of bicalutamide and custirsen. The combination of ARI and custirsen is more effective at increasing cancer cell apoptosis than the combination of flutamide and custirsen.

In addition to increased anti—tumor potency, combination y' may also allow dose reduction strategies to reduce ty. For example, ARI is known to induce side effects such as fatigue and has a maximum tolerated dose of 240mg/day (Scher et al., 2010). However, the present invention discloses that doses of AR; as low as g/day in combination with custirsen are effective to decrease tumor size and. prolong survival in mice. The NIH provides guidance on the conversion of doses used in mouse studies to those riate for human use based on Equivalent Surface Area Dosage Conversion s (NIH Equivalent Surface Area Dosage Conversion Factors Guidance, Posted August 2007: Freidreich et al., 1966).

According to the NIH conversion factor table, the lOmg/kg/day dose described for use in mice herein is equivalent to .83 mg/kg/day in a 60kg human, equaling a dose of about 49.8mg/day for a 60kg human, or about 83mg/day for a lOOkg human. These doses are much lower than the dose of 240mg/kg recommended for phase III trials in humans (Scher et al., 2009). Therefore, an aspect of~ the invention provides a. combination of gnu anti— clusterin oligonucleotide and an AR antagonist ive to treat prostate cancer in which the amount of the AR antagonist in the combination is less than the ive amount used in monotherapy. The surprising potency* of combination therapy comprising an oligonucleotide which reduces Clusterin levels and an AR nist can be used to decrease doses of one or WO 23820 both agents in humans, enabling therapeutic benefit with less side effects. -78— References Abdul, M. and. N. Hoosein, Inhibition. by anticonvulsants of prostate-specific antigen and interleukin—6 secretion by human prostate cancer cells. Anticancer Res, 2001. 21(3B): p. .

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Claims (35)

What is claimed

1. Use of i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure or a pharmaceutically' acceptable salt thereof, in the manufacture of a medicament for treating a mammalian subject afflicted with prostate cancer.

2. The use of claim 1, wherein the cancer is en— ndent prostate cancer.

3. The use of claim 1, wherein the subject has been previously treated with androgen ablation y.

4. The use of any one of claims 1—3, n the amount of the ucleotide and the amount of the androgen receptor antagonist or a pharmaceutically acceptable salt thereof when taken together is more effective to treat the subject than when each agent is administered alone.

5. The use of any one of claims 1-4, wherein the amount of the oligonucleotide in combination with the amount of the androgen receptor antagonist or a pharmaceutically ~88- acceptable salt thereof is less than is ally effective when administered alone.

The use of any one of claims 1-5, wherein the amount of the androgen. receptor antagonist or' a pharmaceutically able salt thereof in combination with the amount of the oligonucleotide is less than is clinically effective when administered alone.

The use of any one of claims 1—6, wherein the amount of the oligonucleotide and the amount of the en receptor antagonist or a pharmaceutically able salt thereof when taken together is effective to reduce a clinical symptom of prostate cancer in the subject.

The use of any one of claims 1—7, wherein the mammalian subject is human.

The use of any one of claims 1—8, wherein the oligonucleotide is an antisense oligonucleotide.

10. The use of claim 9, wherein the antisense oligonucleotide spans either the translation initiation site or the termination site of clusterin—encoding mRNA.

ll. The use of claim 10, wherein the nse oligonucleotide comprises nucleotides in the sequence set forth in SEQ ID NOS: 1 to ll.

12. The use of claim 10, wherein the antisense oligonucleotide comprises nucleotides in the sequence set forth in SEQ ID NO: 3.

l3. The use of claim 11 or 12, wherein the antisense oligonucleotide is modified to enhance in vivo stability relative to an 'unmodified. oligonucleotide of the same 8equence .

14. The use of claim 13, wherein the ucleotide is custirsen.

15. The use of claim 14, wherein the amount of custirsen is less than 640mg.

l6. The use of claim 15, wherein the amount of custirsen is less than 480mg.

l7. The use of any one of claims 14—16, wherein the amount of custirsen is ated for administration intravenously once in a seven day period.

l8. The use of any one of claims l—l7, wherein the amount of the en or antagonist is less than 240mg.

19. The use of any one of claims 1—17, wherein the amount of the androgen receptor antagonist is from 150mg to 240mg.

20. The use of any one of claims 1—18, wherein the amount of the androgen receptor antagonist is from 30mg to 150mg.

21. The use of any one of claims 1—18, wherein the amount of the androgen receptor antagonist is 80mg.

22. The use of any one of claims l-21, wherein the amount of the androgen receptor antagonist is formulated for administration orally once per day.

23. Use of i) an oligonucleotide which reduces clusterin expression and ii) an en receptor antagonist, in the manufacture of a medicament for the treatment of a mammalian subject afflicted with androgen—independent prostate cancer.

24. The use of claim 23, wherein the androgen receptor antagonist is a non—steroidal antiandrogen.

25. The use of claim 23 or 24, wherein the androgen or antagonist is ARl.

26. The use of any one of claims 1—25, wherein the combination of the oligonucleotide and the androgen receptor antagonist is effective to decrease androgen or translocation from the cytoplasm to the s of the tumor cells.

27. The use of any one of claims 1—25, wherein the combination of the oligonucleotide and the androgen receptor antagonist is ive to increase the proteasome degradation of the androgen receptor protein in the tumor cells.

28. The use of any one of claims 1-25, wherein the combination of the oligonucleotide and the androgen receptor antagonist is effective to decrease androgen receptor transcriptional activity in the tumor cells.

29. The use of any one of claims 1—25, wherein the ation of the oligonucleotide and the androgen receptor nist is ive to decrease the amount of phosphorylated AKT in the tumor cells.

30. The use of any one of claims 1—25, wherein the combination of the oligonucleotide and the androgen receptor antagonist is effective to decrease the amount of phosphorylated ERK in the tumor cells.

31. The use of any one of claims 1—25, wherein the combination of the oligonucleotide and the androgen receptor antagonist is effective to inhibit the proliferation of te cancer cells.

32. Use of custirsen in the manufacture of a medicament for increasing the ivity of ARl resistant prostate cancer cells to ARl.

33. A ition for treating a mammalian subject afflicted with prostate cancer comprising i) an oligonucleotide which reduces clusterin expression and ii) an androgen receptor antagonist having the structure FaC H or a pharmaceutically acceptable salt thereof.

34. A composition according to claim 33, wherein the prostate cancer is androgen independent prostate cancer.

35. The use of any one of claims 1, 23 or 32, ntially as herein. described. with. reference to any one of the Examples and/or