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    Arming The Immune System To Fight Cancer: in This Issue

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    SORIN AVRAMESCU
    medicina

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    Arming The Immune System To Fight Cancer: in This Issue

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    SORIN AVRAMESCU
    17 views1 page
    medicina

    Original Title

    246–246

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    medicina

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    17 views1 page

    Arming The Immune System To Fight Cancer: in This Issue

    Uploaded by

    SORIN AVRAMESCU
    medicina

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 1

    In This Issue

    pubs.acs.org/acschemicalbiology

    ■ ARMING THE IMMUNE SYSTEM TO FIGHT CANCER


    Over 500,000 people in the United States died from cancer in
    2010, and especially deadly are cancers that have metastasized,
    or spread to other parts of the body. While the immune system
    may not be capable of killing metastatic cancer cells on its own,
    one promising approach to fighting cancer is to devise a
    method to help the immune system get rid of unwanted toxic
    elements. Jakobsche et al. (DOI: 10.1021/cb200374e) now
    describe a chemical strategy for luring cytotoxic agents of the

    ■
    immune system directly to metastatic cancer cells.
    SUPERRESOLUTION IN THE PALM OF YOUR HAND
    Fluorescent molecules can be transformed into a non-
    fluorescent state when modified with an appropriate photo-
    cleavable compound, a phenomenon called caging. Upon
    activation with light, the caging group is cleaved and the
    fluorophore regains its fluorescent properties. Caging enables
    the exploration of biological processes with high spatial and
    temporal resolution, though subtle challenges in the technology
    have left a need for novel caged fluorophores that can be
    specifically attached to proteins of interest. Now, Banala et al.
    (DOI: 10.1021/cb2002889) report the creation of a caged
    The strategy relies on the fact that many metastatic cancer rhodamine derivative that can be used for the specific labeling
    cells contain higher levels of a protein called urokinase-type of SNAP-tag fusion proteins.
    plasminogen activator receptor, or uPAR, on their surface than
    do healthy cells. uPAR binds to an enzyme called urokinase-
    type plasminogen activator (uPA). The authors created a
    bifunctional small molecule, called ARM-U, that binds to and
    inhibits the activity of uPA, and contains an antibody-
    recruiting antigen. When an ARM-U-uPA complex binds
    uPAR-containing cancer cells, the antigen acts as bait, luring The caged rhodamine exploits the fact that rhodamine
    disease-fighting antibodies to the cancer cells. modified with a urea group is still significantly fluorescent. This

    ■ OUT OF THE LOOP


    Sulfur is an important component of numerous essential
    enabled the creation of a rhodamine derivative modified on one
    end with a photocleavable group and on the other with a urea
    group linked to an O6-benzylguanine group, which specifically
    biomolecules, such as the amino acids methionine and cysteine. reacts with proteins containing a SNAP-tag. The probe was
    In order to make such sulfur-containing compounds, many particularly well-suited for use in photoactivated localization
    microorganisms come equipped with enzymes called sulfonu- microscopy (PALM), in which cellular components can be
    cleotide reductases, which reduce an activated form of sulfate imaged with nanometer resolution.
    called adenosine-5′-phosphosulfate (APS) to sulfite. While
    performing this conversion, some organisms use adenosine-
    5′-phosphosulfate reductase (APR), and others use 3′-phospho-
    adenosine-5′phosphosulfate reductase (PAPR). Because there
    are no human enzymes that are similar to APR and PAPR,
    these sulfonucleotide reductases are intriguing targets for the
    development of new antibiotics. To better understand the
    factors involved in the specificities and activities of these
    structurally similar enzymes, Bhave et al. (DOI: 10.1021/
    cb200261n) investigate the two regions of the enzymes that
    differ, the P-loop and the iron-sulfur cluster.
    The authors use various protein engineering, spectroscopic,
    and kinetic analysis methods to explore the involvement of the
    P-loop and the iron-sulfur cluster in enzyme function. Their
    data unexpectedly reveal that the iron-sulfur cluster, not the
    P-loop, is the major contributor to sulfonucleotide reductase
    specificity and activity. Published: February 17, 2012

    © 2012 American Chemical Society 246 dx.doi.org/10.1021/cb300023x | ACS Chem. Biol. 2012, 7, 246−246

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