Journal of Pathology
J Pathol 2003; 200: 336–347.
Published online 20 March 2003 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/path.1367
Original Paper
Expression of VEGF, semaphorin SEMA3F, and their
common receptors neuropilins NP1 and NP2 in
preinvasive bronchial lesions, lung tumours, and cell lines
Sylvie Lantuéjoul,1 Bruno Constantin,3 Harry Drabkin,4 Christian Brambilla,1 Joëlle Roche2
and Elisabeth Brambilla1 *
1 Laboratoire de Pathologie Cellulaire, INSERM U 578, Grenoble, France
2 IBMIG, FRE CNRS 2224, Université de Poitiers, Poitiers, France
3 LBSC, UMR CNRS 6558, Université de Poitiers, Poitiers, France
4 University of Colorado Health Sciences Center, Division of Medical Oncology,
*Correspondence to:
Professor Elisabeth Brambilla,
Service de Pathologie Cellulaire,
CHU Albert Michallon BP 217,
38043 Grenoble Cedex 09,
France.
E-mail:
EBrambilla@chu-grenoble.fr
Received: 18 July 2002
Revised: 6 November 2002
Accepted: 28 January 2003
Denver, CO, USA
Abstract
Two receptors, neuropilin 1 (NP1) and neuropilin 2 (NP2), bind class 3 semaphorins,
axon guidance molecules including SEMA3F, the gene for which was isolated from a
3p21.3 deletion in lung cancer. In addition, they bind VEGF (vascular endothelial growth
factor), enhancing the effects of VEGF binding to KDR/Flk-1. Elevated VEGF levels are
associated with the loss and cytoplasmic delocalization of SEMA3F in lung cancer, suggesting
competition for their NP1 and NP2 receptors. To determine the timing of these events,
we compared by immunohistochemistry VEGF, SEMA3F, NP1 and NP2 expression in
50 preneoplastic lesions and 112 lung tumours. In preneoplastic lesions, VEGF increased
from low-grade to high-grade dysplasia (p = 0.001) whereas SEMA3F levels remained low.
NP1 and NP2 levels increased from dysplasia to microinvasive carcinoma (p = 0.0001)
and correlated with VEGF expression (p = 0.04 and 0.0002, respectively). Non-small cell
lung carcinoma overexpressed VEGF and NP1 and NP2 significantly more often than
neuroendocrine tumours including small cell lung carcinoma. SEMA3F loss or delocalization
correlated with advanced tumour stage. Migrating cells overexpressed VEGF, SEMA3F,
NP1 and NP2 with cytoplasmic delocalization of NP1 as demonstrated in an in vitro wound
assay. These results demonstrate early alteration of the VEGF/SEMA3F/NP pathway in lung
cancer progression. Copyright 2003 John Wiley & Sons, Ltd.
Keywords: semaphorin (SEMA3F); neuropilins; VEGF; preneoplastic bronchial lesions;
lung tumours
Introduction
Lung cancer is the leading cause of cancer-related
deaths in industrial countries, cigarette smoking being
the main risk factor, responsible for 90% and 78%
of lung carcinoma in men and women, respectively.
Most patients present with advanced disease and a
poor prognosis despite improvements in clinical treatments [1]. Understanding the molecular pathogenesis
of lung cancer may help to provide new and more
sensitive means for early detection of lung cancer
and for its therapy [2]. According to the WHO histological classification [3], the major classes of lung
tumour comprise squamous cell carcinoma (SCC),
small cell lung carcinoma (SCLC), adenocarcinoma
(ADC), large cell carcinoma, including two recently
described variants — large cell neuroendocrine carcinoma (LCNEC) and basaloid carcinoma (BC) — and
typical and atypical carcinoid tumours.
Preneoplastic lesions accompanying and preceding
SCC and BC are suspected to develop in conjunction
with a multistep accumulation of genetic alterations
Copyright 2003 John Wiley & Sons, Ltd.
that progressively transforms normal bronchial epithelium to invasive carcinoma [4]. Morphologically,
lesions progress from hyperplasia to squamous metaplasia, dysplasia of various degrees (mild, moderate
and severe) and then in situ and invasive carcinoma.
Whether hyperplasia and squamous metaplasia represent common reactive changes or true neoplasia
is not certain; they are thus considered along with
mild dysplasia as low-grade preneoplastic lesions. In
contrast, moderate and severe dysplasia and in situ
carcinoma are high-grade premalignant lesions [2,5].
To understand these lesions better from a molecular
standpoint, and to provide specific intermediate endpoints for chemopreventive studies, new biomarkers
are needed to define the stepwise process of lung cancer development and the chronology by which genetic
and epigenetic changes develop [6–8].
VEGF, one of the key factors in tumour angiogenesis [9], is upregulated in numerous benign and
malignant tumours. The biological effects of VEGF165
are mediated by two tyrosine kinase receptors: VEGFR1 (Flt-1) and VEGF-R2 (KDR/Flk-1). The prevailing
VEGF, semaphorin, and neuropilins in lung tumours
concept has been that VEGF is secreted by tumour
cells and its receptors are expressed by endothelial
cells, enhancing their proliferation and migration in
a paracrine manner. VEGF has been substantially
implicated in tumour development since VEGF inhibition suppresses tumour growth in vivo, limiting neovascularization [10]. Moreover, the demonstration of
increased vessel density related to VEGF secretion in
preneoplastic bronchial lesions [11] implicates VEGF
and its receptors in early lung cancer progression.
However, one preneoplastic lesion observed exclusively in smokers — angiogenic squamous dysplasia,
described by Keith et al [12] as micropapillary angiogenic lesions — was not clearly associated with a
greater risk for cancer progression, although VEGF
expression was suspected to be higher than in ordinary
dysplastic lesions occurring in smokers. Thus, the role
or timing of VEGF expression in premalignant lesions
still needs to be defined more precisely.
Two other transmembrane VEGF receptors, NP1
and NP2 [13,14], were initially identified in neuronal cells as receptors for class 3 semaphorins
(see semaphorin nomenclature 1999) [15]. NP1 is
expressed by endothelial cells and corresponds to a
VEGF co-receptor enhancing VEGFR2/KDR binding
[16], tumour angiogenesis and progression [17]. NP1
expression was also reported in adult tissues, exhibiting high levels in heart and placenta, moderate levels
in lung, liver, and kidney, and low levels in brain.
NP1 expression was also identified in tumour-derived
cells such as those from breast and prostate carcinoma [16], suggesting that VEGF might be involved
in an autocrine loop through its neuropilin receptors.
The previous view that VEGF-R1 and R2 were not
expressed on tumour cells has been recently revised.
Several tumour cells also express VEGF-R1 or VEGFR2, including lung cancer cells [18,19], confirming
that tumour cells participate in a functional autocrine
loop via several receptors. NP2, which shares 47%
homology with NP1, is absent from endothelial cells
but is expressed in mouse embryonic lung [20] and
in tumours including osteosarcoma, where its expression correlates with a poor prognosis [21], as well as
in melanoma, where NP1, NP2, and KDR have been
implicated in a proliferative response [22].
The other ligands of neuropilins are class 3
semaphorins [15]. The widespread expression of
semaphorins suggested that they had other functions
outside the nervous system: this was subsequently
demonstrated in normal lung development [23]
and in tumorigenesis [24,25]. As SEMA3F was
previously isolated in SCLC cell lines from a
recurring homozygous deletion at 3p21.3, a region
that also undergoes LOH in tumours, it has been
suggested that this gene is a tumour suppressor gene
[26,27]. While SEMA3A binds only NP1 [13,14],
SEMA3F binds both NP1 and NP2 [28,29] with
10 times more affinity for NP2, and thus shares
these receptors with VEGF165 in endothelial and
tumour cells. Competition between SEMA3A and
Copyright 2003 John Wiley & Sons, Ltd.
337
VEGF165 has been demonstrated [30,31] and a balance
between these two molecules mediates migration and
apoptosis of neural progenitors [32]. Furthermore, we
found that in lung tumours high VEGF expression
was associated with decreased levels of SEMA3F
membrane staining and cytoplasmic delocalization
[25]. This suggested that SEMA3F and VEGF might
compete for binding to their common receptors and
that loss of SEMA3F would confer a growth advantage
to tumours. In the present study, we screened 50
preneoplastic bronchial lesions associated with lung
carcinomas and a larger panel of 112 lung tumours
for expression of VEGF, SEMA3F, NP1, and NP2,
by immunohistochemistry. In addition, we performed
confocal microscopic analysis on a set of normal
and tumour cell lines to characterize the localization
of these proteins and to study the timing of their
expression in a wound assay.
Material and methods
Cell lines
The lung cell lines studied included NHBE (normal
human bronchial epithelial cells), BAES2B (SV40immortalized bronchial epithelium) and NCI-H661
(non-small cell lung carcinoma cells) and they were
compared with HUVEC (human umbilical vein endothelial cells) and HeLa cells (cervical adenocarcinoma
cells). NHBE and HUVEC were obtained from Clonetics and grown in BEGM bullekit media and EGM
bullekit media respectively. BAES2B, NCI-H661 and
HeLa were obtained from ATCC and were grown in
RPMI-1640 containing 10% fetal calf serum under 5%
CO2 .
Tumour tissue samples
One hundred and twelve primary lung tumours were
retrieved from the frozen bank of the Cellular Pathology Department. Local ethical guidelines were followed. Tumours were classified according to the 1999
World Health Organization (WHO) histological classification of lung tumours as follows: 42 squamous
cell carcinoma (SCC), 9 small cell lung carcinoma
(SCLC), 34 adenocarcinoma (ADC), 12 large cell neuroendocrine carcinoma (LCNEC), 4 basaloid carcinoma, and 7 typical and 4 atypical carcinoids (TC
and AC respectively). Fifty preneoplastic bronchial
lesions from 25 patients with associated invasive carcinoma, where preinvasive lesions were identified on
frozen examination of the resection margins, were
studied immunohistochemically, including 10 mild
dysplasia, 14 moderate dysplasia, 12 severe dysplasia and 14 carcinoma in situ (CIS). Among these,
17 disclosed an angiogenic papillary pattern according to the description of Keith et al [12] (one mild
dysplasia, 4 moderate dysplasia, 6 severe dysplasia
and 6 CIS). These preneoplastic lesions were compared with 19 hyperplastic bronchial mucosae and
J Pathol 2003; 200: 336–347.
338
10 squamous bronchial metaplasia identified in the
same resected lung tumours including 16 SCC (12
invasive and 4 microinvasive), 4 basaloid carcinoma
(BC), 3 ADC, and 2 LCNEC. Tumour samples were
obtained from these surgical lung resections or from
mediastinal lymph node biopsies performed during
mediastinoscopy in non-operable patients as a diagnostic procedure. One of the tumour samples was
quickly frozen before histological sampling. For clinicopathological correlation, TNM disease stages were
evaluated according to the international UICC classification. Eighteen of 42 SCC, 1 of 4 BC, 6 of 34
ADC, 1 of 11 carcinoid tumours, 6 of 12 LCNEC,
and all SCLC patients presented at advanced tumour
stage (III–IV).
Immunohistochemical analysis of tissue samples
Immunostaining of VEGF, SEMA3F, NP1, and NP2
was performed on frozen sections. The primary
rabbit polyclonal antibodies used were anti-VEGF
A20 (Santa Cruz Biotechnology, Santa Cruz, USA)
at a dilution of 1 : 800, anti- SEMA3F, previously
described [33] and used at a dilution of 1 : 50, anti-NP1
(Santa Cruz Biotechnology, Santa Cruz, USA) at a
dilution of 1 : 100, and anti- NP2 (Santa Cruz Biotechnology, Santa Cruz, USA) at a dilution of 1 : 100.
After fixation in cold acetone for 10 min and blocking of non-specific binding with 2% donkey serum for
30 min, a three-stage indirect immunoperoxidase technique was used: incubation with the primary antibody
at 4 ◦ C overnight, followed by the secondary biotinylated donkey anti-rabbit immunoglobulin G (Jackson,
Baltimore, PA) (1 : 1250) then the amplification system avidin–biotin complex (Dakopatts, Glostrup, Denmark) (1 : 200). Negative control consisted of omission of the primary antibody and incubation with
immunoglobulin of the same species at the same final
concentration. To assess the specificity of VEGF and
SEMA3F antibodies, in vitro immunoneutralization
was performed by preincubating the primary antibody with a 10 times excess weight of immunizing
peptides (VEGF A20 blocking peptide, Santa Cruz,
and the 16-amino acid SEMA3F peptide) for 2 h at
room temperature in order to abolish the immunostaining. No blocking peptides were available for NP1
and NP2 in vitro immunoneutralization, but these
antibodies (from Santa Cruz) gave immunostaining
results with 85% concordance (intensity and percentage of labelled cells) with NP1 and NP2 antibodies kindly provided by A. Kolodkin on 104 lesions
from these series stained concomitantly with the two
NP1 and NP2 antibodies. Staining scores were established by semi-quantitative optical analysis, using the
product of percentage of positive cells and staining
intensity from 1 to 3 (1 weak, 2 moderate, and 3
strong), and therefore ranged from 0 to 300. Cases
with a score greater than 10 were considered to be
positive.
Copyright 2003 John Wiley & Sons, Ltd.
S Lantuéjoul et al
Immunostaining and confocal microscopy on cell
lines
For NP1 and NP2 immunostaining, cell fixation was
performed in 1% paraformaldehyde for 15 min with
saponin 0.1% permeabilization for 10 min. Anti-NP1
rabbit polyclonal antibody (gift from Dr A. L. Kolodkin, Baltimore) raised against amino acids 583–856
of rat NP1 [13] was used at a dilution of 1 : 1000.
Anti-NP2 polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, USA) was used at a dilution of
1 : 100. Immunostaining for SEMA3F was performed
as described previously [25]. Cells were exposed in
the dark to a second RRX-conjugated goat anti-rabbit
antibody diluted at 1 : 200 (Jackson Immunoresearch
Lab, Inc.) and mounted using Vectashield (Vector,
Burlingame, CA, USA). Immunostained samples were
examined using the yellow line (568 nm) of the confocal microscope (BioRad MRC, Hemel Hempstead,
UK) equipped with a 15 mW argon–krypton gas
laser.
Quantitative RT-PCR
In order to confirm the presence of transcripts sustaining expression of the proteins detected immunohistochemically, and to justify the validity of the antibodies, we investigated the presence of VEGF, SEMA3F,
NP1, and NP2 mRNA in addition to protein expression in 11 lung tumours (6 SCC and 5 ADC) and
two cell lines using real-time RT-PCR, where protein
expression was immunohistochemically assessed. The
frozen material used for mRNA extraction was analysed morphologically on a frozen section in order to
assess the proportion of stromal cells. The cases chosen for this comparison (mRNA–protein) contained
more than 60% tumour cells (less than 40% stromal
cells). It would not have been accurate to compare
expression in tumours to normal lung, as the latter
is a highly vascularized tissue where endothelial cells
are the predominant cell type. Therefore, an immortalized cell culture derived from lung epithelium, NHBE,
was used as normal lung epithelium. Conversely, NCIH661, which failed to exhibit positive immunocytochemical staining with NP1 and NP2 antibodies, was
studied to estimate NP1 and NP2 transcripts.
Total RNA and cDNA were prepared as described
previously [25]. We assessed levels of SEMA3F, NP1,
NP2, and VEGF transcription relative to G3PDH in
lung tumours by quantitative real-time RT-PCR carried out using the GeneAmp 5700 (ABI) system
with SYBR Green chemistry as described previously
[25]. PCR was carried out in 50 µl reaction volumes consisting of 1 × PCR SYBR Green buffer,
0.25 µM primers, 200 µM dNTPs, and 0.03 units/µl
AmpliTaq Gold (Perkin-Elmer). cDNA was amplified
as follows: 50 ◦ C for 2 min, 95 ◦ C for 10 min, followed by 40 cycles at 95 ◦ C × 15 s, 60 ◦ C × 1 min.
SEMA3F, NP1, NP2, and VEGF cDNA were amplified with the following primers: SEMA3F forward
J Pathol 2003; 200: 336–347.
VEGF, semaphorin, and neuropilins in lung tumours
5′ AGCAGACCCAGGACGTGAG3′ and SEMA3F reverse 5′ AAGACCATGCGAATATCAGCC3′ giving a
112 bp product; VEGF165 forward 5′ CAAGACAAGAAAATCCCTGTGG3′ and VEGF165 reverse 5′ CCTCGGCTTGTCACATCTG3′ giving a 162 bp product;
NP2 forward 5′ GGATGGCATTCCACATGTTG3′ and
NP2 reverse 5′ ACCAGGTAGTAACGCGCAGAG3′
giving a 152 bp product; NP1 forward 5′ ATCACGTGCAGCTCAAGTGG3′ and NP1 reverse 5′ TCATGCAGTGGGCAGAGTTC3′ giving a 167 bp product. The
raw data were obtained in terms of Ct values, which
refers to the PCR cycle number during exponential
amplification at which the product (measured in real
time by SYBR Green fluorescence) crosses an arbitrary threshold. To adjust for variations in the amount
of RNA, the Ct values for each gene were normalized against the Ct values for the housekeeping gene
G3PDH (ie delta Ct = Ctspecific gene − CtG3PDH ). While
the resulting delta Ct values are experimentally convenient, they are not readily intuitive (ie they reflect
exponential amplification and higher delta Cts represent lower expression). Instead, the results are displayed in terms of the relative expression (×1000)
compared to G3PDH. For instance, a value of 1000
is equal to the expression of G3PDH and a value of
100 is equivalent to 10% of the G3PDH level.
Statistical analysis
The staining scores were compared in different categories using the Mann–Whitney U -test,
Kruskal–Wallis H and Spearman tests. All the tests
were performed with the Stat View programme (Abacus Concepts, Berkeley, CA).
Results
Immunohistochemical analysis of VEGF in normal
lung, preinvasive bronchial lesions, and
corresponding invasive carcinomas (Table 1)
VEGF was highly expressed in normal lung by
bronchial basal cells (Figure 1A), as well as by hyperplastic type II pneumonocytes (scores = 100–200).
339
Cytoplasmic staining was associated with stronger
membrane staining at the apical surface. Endothelial
cells and smooth muscle cells were also stained, but
with lower scores not exceeding 50.
In preinvasive and invasive bronchial lesions,
epithelial cells, endothelial cells, and stromal fibroblasts exhibited strong VEGF cytoplasmic staining,
often with membrane accentuation (Figure 1B, J).
VEGF expression increased significantly with the
severity of histological grade in preneoplastic lesions
(p = 0.0001). Scores were significantly lower in
hyperplastic mucosa than in squamous metaplasia
and mild dysplasia (p = 0.0017), and lower in lowgrade preneoplastic lesions (squamous metaplasia and
mild dysplasia) than in high-grade lesions (moderate, severe dysplasia and CIS) (p = 0.0001). VEGF
scores were also higher in severe dysplasia and CIS
than in microinvasive and corresponding invasive carcinomas, SCC and BC (p = 0.014). Moreover, high
VEGF expression was observed in discrete clusters of
dysplastic cells of low-grade preneoplastic lesions, and
became homogeneous and more intense in corresponding high-grade lesion from the same patient. Overall,
increasing levels of VEGF expression were observed
during the process of preneoplastic transformation that
culminated in invasive carcinoma.
No difference could be detected between VEGF
expression in angiogenic papillary preneoplastic
lesions (angiogenic squamous dysplasia) and that
of classical dysplastic lesions of similar histological
grade.
Immunohistochemical analysis of SEMA3F in
normal lung, preinvasive lesions, and
corresponding carcinomas (Table 1)
SEMA3F was expressed on alveolar type II
pneumonocytes with a membrane pattern (score =
300) and on bronchial basal and bronchiolar cells
with a cytoplasmic and membrane pattern (score =
100) (Figure 1C). Endothelial cells of alveolar
capillaries remained negative, whereas those of
arterioles and venules displayed mild cytoplasmic
staining without membrane staining. In preinvasive
and invasive bronchial lesions, SEMA3F staining
Table 1. Immunostaining scores for VEGF, SEMA 3F, NP1, and NP2 in preneoplastic bronchial lesions and
corresponding SCC and BC (mean scores ± SD)
Histology
N
VEGF
mean scores
± SD
Hyperplastic mucosae
Squamous metaplasia
Mild dysplasia
Moderate dysplasia
Severe dysplasia
In situ carcinoma
Microinvasive carcinoma
Corresponding SCC and BC
19
10
10
14
12
14
4
16
17 ± 36
47 ± 53
25 ± 13
92 ± 62
172 ± 84
166 ± 81
103 ± 54
111 ± 65
SEMA3F
mean scores
± SD
NP1
mean scores
± SD
NP2
mean scores
± SD
27 ± 59
1±2
37 ± 76
40 ± 50
61 ± 69
68 ± 77
69 ± 90
70 ± 71
76 ± 31
131 ± 78
152 ± 71
169 ± 53
175 ± 80
166 ± 69
200 ± 61
84 ± 53
72 ± 26
117 ± 71
140 ± 71
174 ± 49
186 ± 53
169 ± 58
188 ± 73
99 ± 57
SCC, squamous cell carcinoma; BC, basaloid carcinoma.
Copyright 2003 John Wiley & Sons, Ltd.
J Pathol 2003; 200: 336–347.
340
S Lantuéjoul et al
VEGF
SEMA3F
NP1
NP2
C
E
G
B
D
F
H
J
L
N
Q
K
M
P
R
*
A
Figure 1. Immunohistochemical staining of normal bronchial epithelium, preneoplastic lesions and in corresponding lung tumours
(immunoperoxidase staining). Normal bronchial epithelium and preneoplastic lesions (A–H): (A,B) VEGF immunostaining is restricted
to the basal layer in normal bronchioles (A). It is strongly expressed and extends throughout the full thickness of the epithelium
in this severe dysplasia (B). (C, D) Semaphorin 3F immunostaining is moderate in normal bronchial epithelium (C) and faint in
this severe dysplasia (D). (E,F) NP1 immunostaining on bronchial cells with membrane accentuation on basal cells (E). Strong NP1
expression is shown in this severe dysplasia, with a membrane pattern of staining (F). (G,H) NP2 immunostaining with moderate
intensity on normal bronchial cells (G). This staining is expended to the full thickness in severe dysplasia (H). Migration and invasion
in corresponding lung tumours (J–R): (J, K) Strong cytoplasmic and membrane VEGF staining in a squamous cell carcinoma (SCC) with
small clusters of cells isolated in the stroma, infiltrating away from the tumour bulk on serial sections (J) and, in an adenocarcinoma
(ADC), cells in trabeculae invading an arterial vessel wall (∗ lumen, → muscular media) (K). (L, M). Moderate SEMA3F cytoplasmic
staining in the same lesions as J and K (SCC: L and ADC: M). (N, P) Strong NP1 cytoplasmic staining with membrane accentuation
in the same lesions as J and K (SCC: N and ADC: P). (Q, R) Strong cytoplasmic NP2 staining in the same lesions as J and K (SCC:
Q and ADC: R, with membrane staining)
Copyright 2003 John Wiley & Sons, Ltd.
J Pathol 2003; 200: 336–347.
VEGF, semaphorin, and neuropilins in lung tumours
varied from either cytoplasmic to cytoplasmic
and membranous (Figures 1D, L). Weak SEMA3F
staining was observed in hyperplastic mucosa and
squamous metaplasia, while mean scores were slightly
higher in dysplasia, CIS, and in corresponding
microinvasive and invasive SCC and BC. However,
no statistical differences were observed between
different histological grades whether considered
individually, or when low-grade and high-grade
preneoplastic lesions were compared. This mild
increase in scores was considered to be the result
of a higher number of positive cells consistent
with polystratification of positive basal cells and
increased thickness of the epithelium, but was not
due to increased staining intensity of individual
cells. In contrast with low-grade preneoplastic lesions,
SEMA3F expression was predominantly cytoplasmic
in high-grade preneoplastic lesions and their invasive
counterparts. These results indicate that reduced
SEMA3F staining and cytoplasmic delocalization
occur early in lung cancer pathogenesis.
Immunohistochemical analysis of NP1 and NP2 in
normal lung, preinvasive lesions, and
corresponding carcinomas (Table 1)
In normal lung, NP1 and NP2 expression was detected
exclusively in bronchial basal cells of normal epithelium with a cytoplasmic and membrane pattern, and
in smooth muscle cells with a cytoplasmic pattern
(scores = 200–300) (Figure 1E, G). In preinvasive
and invasive bronchial lesions, NP1 and NP2 staining
was cytoplasmic in epithelial cells with strong membrane accentuation (Figure 1F, H, N, Q). Endothelial cells stained strongly with the NP1 antibody and
weakly with the NP2 antibody.
The mean NP1 and NP2 scores increased significantly from hyperplastic mucosa, squamous dysplasia,
mild dysplasia, and moderate dysplasia, reaching a
plateau in severe dysplasia, CIS, and microinvasive
carcinoma. Severe dysplasia and CIS exhibited high
scores (>120) for both NP1 and NP2. In low- and
high-grade preneoplastic lesions, some clusters of dysplastic cells exhibited strong NP1 and NP2 staining.
In contrast to severe dysplasia, CIS and microinvasive
areas, mean scores decreased in frankly invasive areas
of SCC and BC (p = 0.0001 for NP1 and NP2 respectively). Only 7/12 cases with anti-NP1 and 8/12 cases
with anti-NP2 had scores greater than 50.
341
0.04) and between VEGF and NP2 (p = 0.0002). No
correlation was found between SEMA3F and NP1 or
NP2 score in preneoplastic lesions or in corresponding invasive SCC and BC. Although no significant
inverse relationship was identified between VEGF and
SEMA3F staining, the rank of VEGF expression was
significantly higher than that of SEMA3F expression
in both low-grade and high-grade preinvasive lesions
(p = 0.001 for both; Mann–Whitney test).
VEGF, SEMA3F, NP1, and NP2
immunohistochemical expression in lung tumours
(Table 2)
VEGF was expressed in most lung tumours but mean
VEGF scores were significantly higher in SCC and
ADC than in neuroendocrine tumours (p = 0.0016).
The expression of VEGF was often more intense
at the periphery of the tumour lobules than inside.
Small clusters of cells isolated from the tumour
bulk in the stroma or invading vascular structures
were highly stained (Figure 1J, K). Stromal cells
including endothelial cells and fibroblasts also strongly
expressed VEGF in a diffuse pattern.
SEMA3F was lost in 30/80 (37%) of NSCLC, with
low mean scores in SCC, LCNEC, and SCLC, in contrast to those observed in ADC and carcinoid tumours
(p = 0.0001). Diffuse cytoplasmic staining predominated in most histological subtypes, in contrast to
carcinoid tumours and bronchioloalveolar carcinoma,
which exhibited membrane and cytoplasmic staining
in 82% of cases. These latter tumours exhibited a
unique pattern of SEMA3F/VEGF expression, with
SEMA3F scores being higher than those of VEGF and
with maintenance of a membrane staining pattern for
SEMA3F. In other tumour types, small clusters of cells
in the peritumoural stroma, which appeared to represent migrating tumour cells, exhibited strong membrane staining with SEMA3F antibody (Figures 1L,
M) concomitant with VEGF expression. Stromal cells
Table 2. Immunostaining distribution and scores for VEGF,
SEMA3F, NP1, and NP2 in each histological type of lung tumour
(number of cases followed by % of positive cases, and mean
scores ± SD)
Histology
N
VEGF
SEMA3F
NP1
NP2
SCC
42
35 (85%)
116 ± 64
2 (50%)
62 ± 75
26 (76%)
118 ± 73
9 (81%)
78 ± 69
12 (100%)
82 ± 98
7 (77%)
41 ± 55
20 (48%)
66 ± 65
2 (50%)
7.5 ± 9
28 (82%)
126 ± 71
11 (100%)
162 ± 89
8 (63%)
45 ± 54
8 (88%)
55 ± 53
27 (64%)
79 ± 57
3 (75%)
72 ± 22
17 (50%)
60 ± 52
6 (54%)
28 ± 36
9 (73%)
37 ± 39
2 (22%)
7 ± 13
32 (76%)
87 ± 55
4 (100%)
107 ± 61
28 (82%)
88 ± 47
9 (81%)
46 ± 36
11 (90%)
78 ± 44
6 (66%)
38 ± 40
BC
Statistical correlations between expressions of
VEGF, SEMA3F, NP1, and NP2 in preinvasive
bronchial lesions and invasive carcinoma
A significant correlation was observed between VEGF
and NP2 expression (p = 0.02), and between VEGF
and NP1 expression (p = 0.05) in hyperplasia and
low-grade preneoplastic lesions. Similarly, a significant correlation was observed in high-grade preneoplastic lesions, microinvasive and corresponding invasive SCC and BC between VEGF and NP1 (p =
Copyright 2003 John Wiley & Sons, Ltd.
4
ADC
34
TC + AC
11
LCNEC
12
SCLC
9
SCC, squamous cell carcinoma; BC, basaloid carcinoma; ADC,
adenocarcinoma; TC, typical carcinoid; AC, atypical carcinoid; LCNEC,
large cell neuroendocrine carcinoma; SCLC, small cell lung carcinoma.
J Pathol 2003; 200: 336–347.
342
were negative with the exception of 20% of endothelial
cells.
Both NP1 and NP2 were expressed in most SCC
and ADC cases. The pattern of staining was predominantly cytoplasmic with membrane accentuation.
As for VEGF and SEMA3F, clusters of tumour
cells isolated in the stroma were strongly stained
(Figure 1N, P, Q, R). In neuroendocrine tumours (TC,
AC, LCNEC, SCLC), NP1 and NP2 levels were significantly lower than in SCC and ADC (p = 0.0001 and
p = 0.0031) and also more heterogeneous, the lowest
NP1 scores being observed in SCLC. As for nonneuroendocrine tumours, NP1 and NP2 staining was
mainly cytoplasmic with membrane accentuation in
LCNEC and carcinoid tumours, whereas SCLC exhibited predominantly cytoplasmic staining.
Statistical correlation between expressions of
VEGF, SEMA3F and their receptors NP1 and NP2
in lung tumours
High levels of NP1 and NP2 expression correlated with high levels of VEGF (p = 0.0043 and
p = 0.0008) when all histological types of tumours
were considered, to a lesser extent in non-small cell
lung carcinoma (p = 0.03 for NP1 and p = 0.01 for
NP2), but not in neuroendocrine tumours, where NP1
and NP2 expression was rather low. The low levels of SEMA3F, VEGF, and NP1–NP2 expression
in high-grade NE tumours differ from the patterns
observed in carcinoid tumours especially with respect
to high SEMA3F expression with a membranous pattern. When considering all tumours combined, we
were unable to find a significant inverse correlation between VEGF and SEMA3F staining. However,
the rank of VEGF levels of expression was significantly higher than that of SEMA3F in SCC, BC, and
LCNEC (p = 0.007) (Mann–Whitney test). There was
no significant correlation between NP1 and NP2 and
SEMA3F. However, when the pattern of SEMA3F
staining was considered, higher NP1 scores (ie >150)
where observed when SEMA3F staining was only
cytoplasmic, both when all lung tumours were analysed together (p = 0.03), and when only SCC and
ADC were considered (p = 0.003) (Mann–Whitney
test).
Statistical correlation with clinical stage
As previously noted [25], levels of SEMA3F were
significantly lower in advanced tumour stages (III
and IV) than in limited stages (I–II) either in nonsmall cell lung carcinomas (SCC, BC and ADC) (p =
0.0012) (Mann–Whitney test) or when all tumours
were considered together (p = 0.0001). In contrast,
neither VEGF, NP1, nor NP2 scores correlated with
stage of disease.
Copyright 2003 John Wiley & Sons, Ltd.
S Lantuéjoul et al
Neuropilin subcellular distribution analysed by
confocal microscopy in normal and tumour cell
lines
Immunostaining of NHBE cells showed a predominantly membrane pattern of NP1 (Figure 2A), consistent with its role as a transmembrane receptor. This
pattern of staining was also observed in various lungderived cell lines, like BEAS2B (SV40-immortalized
bronchial epithelium) (Figure 2B) and cervical
adenocarcinoma-derived HeLa cells (Figure 2G, J).
The membrane staining of NP1 was often brighter
at intercellular contacts (Figure 2A, B, G, arrowheads), which suggests an association with cell–cell
adhesion structures. Faint granular cytoplasmic staining was also associated with the predominant membrane pattern of NP1. In lung cancer NCI-H661 cells,
NP1 and NP2 immunostaining could barely be distinguished from the fluorescent background signal consistent with no specific signal in both cases (Figures 2C,
D). The endothelial HUVEC cell line displayed cytoplasmic and membrane staining for both NP1 and NP2
receptors (Figure 2E, F), consistent with paracrine
regulation of angiogenesis by secreted VEGF and
semaphorins.
Further examination of the subcellular distribution
of NP1 in HeLa cells revealed translocation from
plasma membrane to cytoplasm depending on cell
activity. HeLa cells grown at low density exhibited a
majority of interconnected cells with membrane NP1
localization (Figure 2G). However, the cytoplasmic
projections in some isolated cells with lamellipodia
projections were brightly stained by NP1 antibodies
(Figure 2G, arrows). This suggests translocation of
NP1 receptors associated with cell migration. Moreover, migrating cells with intense staining of NP1
at the leading edge of lamellipodia also exhibited
high SEMA3F staining [25]. In accordance with these
observations, HeLa cells with predominantly cytoplasmic distribution of NP1 were rarely observed among
confluent cells (Figure 2H), while the occurrence of
the cytoplasmic pattern increased from 33% to 51%
from the border of a wound through the confluent
cell layer (Figure 2J). Since cells at the wound border are apparently stimulated for migration, upregulation of NP1 or translocation to the cytoplasm may be
associated with cell invasiveness. Interestingly, some
cells located at the border of the wound also displayed brighter staining for SEMA3F (not shown)
polarized in the direction of cell migration. Thus, transient upregulation of cytoplasmic SEMA3F may be
involved in the control of cell motility with loss of
this control occurring in cells from high-grade tumours
which exhibit downregulation of SEMA3F expression.
On the contrary, NP1 cytoplasmic receptors that are
abundantly expressed in high-grade tumours might be
implicated in the invasiveness induced by VEGF signalling.
J Pathol 2003; 200: 336–347.
VEGF, semaphorin, and neuropilins in lung tumours
A
NP1
B
NP1
NHBE
C
NP1
BAES-2B
D
NP2
H661
E
NP1
H661
F
NP2
HUVEC
HUVEC
G
NP1
HeLa
HJ
NP1
J
NP1
Wound edge
H
343
mRNA expression of VEGF, SEMA3F, NP1, and
NP2 in lung tumours and cell lines compared with
protein expression (Table 3)
In order to assess the presence and level of transcripts
and their relationship to protein expression, we compared, in 11 lung tumours and two cell lines, the
presence of VEGF, SEMA3F, NP1 and NP2 mRNA
with the levels of protein expression observed with
all the antibodies used. In NHBE, the high mRNA
levels of expression of VEGF and SEMA3F were consistent with the high protein expression observed by
immunohistochemistry in normal bronchi (Figure 1A,
C), while NP1 and NP2 mRNA were lower. Conversely, the NCI-H661 cell line, which was considered to be negative for NP1 and NP2 expression on
the basis of immunocytochemistry, failed to demonstrate the corresponding mRNA, while VEGF and
SEMA3F mRNA levels were observed to be low. In
lung tumours, SEMA3F, VEGF, NP1 and NP2 mRNA
levels showed variations. In tumour 11, the absence of
NP1 mRNA and very low NP2 mRNA correlated with
the lack of NP1 protein and very low NP2 protein
expression as shown by immunohistochemical staining. In contrast, in three lung tumours (tumours 2, 4,
5), we did not observe any staining with both NP1
antibodies despite the presence of NP1 mRNA, suggesting either low antibody sensitivity or absence of
protein synthesis. No case revealed positive staining
in the absence of mRNA for any protein studied.
Table 3 also includes a comparison of the staining
scores observed with the commercially available NP1
and NP2 antibodies (Santa Cruz Biotechnology, Santa
Cruz, USA) with those observed with antibodies
against NP1 and NP2 provided by Dr A. L. Kolodkin
in the same series. In 9 out of 11 and in 8 out of
11 cases respectively, a score variation of less than
30/300 was observed, allowing a concordance of 82%
and 73% for the NP1 and NP2 antibodies from both
sources respectively. This high concordance illustrated
in 11 lung tumours is in agreement with that observed
with 104 tissues from our series (see Material and
methods), validating the use of both the commercially
available NP1 and NP2 antibodies and those from
A. L. Kolodkin.
Confluent
Figure 2. NP1 and NP2 subcellular distribution in normal
human bronchial epithelial (NHBE) cells, immortalized epithelial
(BAES2B) cells, and the lung tumour cell line NCI- H661,
compared with endothelial HUVEC and HeLa cell lines
analysed by confocal microscopy (RRX immunostaining). NP1
immunochemistry was performed for NHBE (A), BAES2B (B),
NCI-H661 (C), and HUVEC (E) cell lines, HeLa (G–J). NP2
immunochemistry was performed in NCI-H661 (D), HUVEC
(F) cell lines. NP1 was present in the cytoplasm of isolated
motile cells and at the leading edge of lamellapodia (G, arrows).
In non-motile cells, the plasma membrane staining of NP1 was
often brighter at intercellular contacts (G, arrowheads). In
confluent cells, most NP1 was located at the membrane and
only a few cells were labelled in the cytoplasm (H). On the
contrary, cells at the border of a wound (dotted line) were
positive for NP1 in the cytoplasm (J)
Copyright 2003 John Wiley & Sons, Ltd.
Discussion
VEGF expression, and in some instances expression of
the VEGF receptors Flk-1 and Flt-1, has been reported
in a variety of premalignant lesions, invasive tumours,
and cell lines, including cervical intraepithelial neoplasia, colonic carcinoma, glioma, breast carcinoma,
gastric carcinoma, melanoma, head and neck cancer,
lung cancer [18,19,34,35], as well as in squamous dysplastic cells [35]. In the present study, we identified
a significant increase in VEGF expression in most
of the preneoplastic bronchial lesions ranging from
moderate to severe dysplasia and in situ carcinoma,
J Pathol 2003; 200: 336–347.
344
S Lantuéjoul et al
Table 3. Analysis of 11 lung tumours and two cell lines for VEGF, SEMA3F, NP1, and NP2 expression by real-time quantitative
RT-PCR and comparison with corresponding staining scores for protein expression obtained by immunohistochemistry
NP1 scores
NP2 scores
Tumours:
VEGF
VEGF
SEMA3F
SEMA3F
NP1
histological type
mRNA
scores
mRNA
scores
mRNA
K
SC
mRNA
K
SC
Tumour 1: ADC
Tumour 2: SCC
Tumour 3: SCC
Tumour 4: ADC
Tumour 5: ADC
Tumour 6: ADC
Tumour 7: ADC
Tumour 8: SCC
Tumour 9: SCC
Tumour 10: SCC
Tumour 11: SCC
Cell lines
NHBE
NCI-H661
53.66
13.6
8.37
45.44
60.37
16.63
360.98
45.44
12.69
16.06
17.82
100
240
0
20
30
60
160
100
100
120
100
58.72
58.72
13.32
23.04
52.56
7.87
61.64
67.92
96.72
35.16
25.03
50
0
240
300
20
100
160
30
160
160
30
13.6
9.16
3.15
7.39
12.96
5.01
35.16
1.6
3.85
1.39
0.062
160
0
160
0
0
0
80
0
0
60
0
160
0
60
0
0
20
80
30
100
60
10
3.96
0.79
1.47
2.12
8.85
4.19
7.7
10.82
4.04
1.98
0.87
160
30
60
160
60
50
160
80
50
120
60
160
0
50
80
50
50
100
50
100
60
60
27.2
9.29
31.25
4.74
2.76
0.01
NP2
7.55
0.32
Results expressed in terms of relative expression (×1000) compared with G3PDH.
K for antibodies provided by A. L. Kolodkin, SC for commercial antibodies.
SCC, squamous cell carcinoma; ADC, adenocarcinoma.
with a rather constant level of expression in corresponding microinvasive and invasive cancers. This is
in agreement with a previous report demonstrating
strong VEGF expression in high-grade laryngeal dysplasia [36]. However, there have been other reports
of bronchial or head and neck premalignant lesions
where no statistical difference in VEGF expression
was observed despite significant increases in microvascular density [11]. These discrepancies may be technical in nature or suggest that VEGF entails other
functions than angiogenesis in tumours such as an
autocrine loop on tumour cells themselves, migration
or survival. We failed to detect any differences in
VEGF expression between angiogenic squamous dysplasia and other classical dysplasia, suggesting that
this morphological variant has causes other than elevated VEGF expression per se. Consistent with this
assumption angiogenic squamous dysplasia is exclusively encountered in cigarette smokers, and stimulation of angiogenesis and tumour growth by nicotine
has been recently demonstrated in a mouse model [37].
Alternatively, it is becoming increasingly clear that
VEGF has independent effects on tumour cells, possibly acting through VEGF receptors and/or NP receptors, such as the autocrine survival activity reported by
Bachelder et al in breast cancer cells [38]. A functional
VEGF/VEGFR2 autocrine loop was demonstrated in
gastric tumour cell lines [19]. Similarly, in melanoma
VEGF was shown to have positive effects on migration
acting through an integrin-dependent pathway involving phosphatidylinositol-3-kinase [39]. Interestingly,
VEGF was shown to stimulate cellular invasion of
breast cancer cells, signalling through the same PI3
kinase pathway despite low levels of Flt-1 and KDR
mRNA [40]. Thus, it is not surprising that elevated levels of VEGF can be observed in premalignant lesions
independently of neoangiogenesis.
Copyright 2003 John Wiley & Sons, Ltd.
As previously reported in lung cancers [11,18,25],
VEGF is widely expressed in SCC and ADC, with
cytoplasmic staining associated with strong membrane
staining. In microinvasive and invasive SCC, tumour
cells either at the periphery of lobules or isolated in the
stroma were strongly VEGF positive, consistent with a
role for VEGF in cell migration. We failed to observe
any correlation between VEGF overexpression and
advanced stages of the disease, in keeping with our
previous results [18]. In contrast with non-small cell
carcinomas, we observed that VEGF was weakly
expressed in neuroendocrine tumours, particularly in
SCLC. Interestingly, c-myc overexpression, which is
frequent in SCLCs, has been reported to downregulate
VEGF transcription [41].
In contrast to VEGF, SEMA3F expression was
lost early in preinvasive lesions and corresponding
tumours. This is consistent with reports that 3p21.3
loss of heterozygosity is both frequent and appears to
be the earliest 3p event in lung cancer development
[42]. Expression of the second allele might also be
impaired. Because loss of SEMA3F staining occurred
in most premalignant lesions, we did not observe differences between dysplasia of any type and in situ or
invasive carcinoma. As was expected based on our previous studies, low levels of SEMA3F expression were
observed in lung tumours with reduced or absent membrane staining and cytoplasmic delocalization, except
in carcinoid tumours and well-differentiated adenocarcinomas. Interestingly, in these tumours VEGF scores
were lower than SEMA3F, which is a unique situation among lung tumours. Thus, the preservation of
SEMA3F membrane staining may depend on VEGF
expression with competition for NP binding at the cell
surface, as well as being affected by 3p LOH.
Although we did not observe any correlation
between VEGF overexpression and advanced stages
of disease, we confirmed a strong correlation between
J Pathol 2003; 200: 336–347.
VEGF, semaphorin, and neuropilins in lung tumours
loss of membrane to cytoplasmic delocalization
of SEMA3F and advanced stage, suggesting that
SEMA3F functions are impaired in lung cancer.
In support of this, another gene involved in the
semaphorin pathway, collapsin response mediator
protein-1 (CRMP-1), has been recently shown to
correlate inversely with the invasive capability of lung
cancer cell lines [43]. Thus, there is growing evidence
from independent sources indicating that the loss of
semaphorin signalling is important in lung cancer
development.
Upregulation of NP1 has been implicated in tumour
progression as it has been correlated with advanced
stages in prostatic tumours and malignant behaviour
in astrocytomas [44,45]. In breast cancer cell lines,
VEGF has been reported to act as an autocrine survival
factor [38] and in gastric adenocarcinoma cells as an
autocrine factor for proliferation [19]. Interestingly, a
NP1 blocking antibody eliminated this function in the
absence of demonstrable Flk-1/KDR expression [38]
and NP1 expression has been described in various
tumour cell lines with or without concomitant KDR
[16,19]. Our wound assay suggests that NP1 functions
in cell migration as has already been demonstrated in
vitro in rat prostate carcinoma [17]. However, whether
NP1 cytoplasmic delocalization and increase of its
expression are consistent with the activation of an
NP1-dependent pathway leading to increased endocytosis cannot be assessed from the present results.
Nevertheless, it would be consistent with our finding
of NP1/NP2 overexpression in tumour cells migrating
away from the tumour bulk. Like NP1, NP2 overexpression was reported in osteosarcomas and melanoma
in association with VEGF expression, angiogenesis,
and tumour growth [21,22]. In preinvasive bronchial
lesions, we demonstrated a strong increase of NP1 and
NP2 with more aggressive histological grades of dysplasia and in situ carcinoma. As perhaps anticipated,
lung tumours expressing high VEGF levels also overexpressed NP1 and NP2 with a statistical direct correlation. Selective induction of NP1 by VEGF and membrane translocation has been demonstrated in bovine
endothelial cells at the level of mRNA and protein
synthesis [46]. NP2 could well be stimulated also by
VEGF in endothelial cells via VEGFR2 [19]. In contrast to what was observed in SCC and ADC, the
VEGF/SEMA3F/NP pathway appears to be characterized by the preservation of SEMA3F expression
in carcinoid tumours. Conversely SCLC, a high-grade
neuroendocrine tumour, exhibited much lower levels
of VEGF and NP expression concomitant with the loss
or marked reduction of SEMA3F in most cases. We
also observed, in tumours, individual tumour cells or
tumour cell clusters which stained strongly for VEGF,
SEMA3F and neuropilins. Whether low-grade preinvasive lesions containing clusters of VEGF-positive
cells signify a worse prognosis is currently unknown
but deserves further study. While VEGF expression
in addition to neuropilins might be dynamic in lowgrade lesions, VEGF might be involved in selection
Copyright 2003 John Wiley & Sons, Ltd.
345
of clones during tumour progression as most highgrade preinvasive lesions were positive. On the other
hand, SEMA3F overexpression may inhibit cell migration and may function as an anti-survival factor. In
favour of this, we have shown that SEMA3F overexpression induces apoptosis in mammary adenocarcinoma cells (Nasarre et al, personal communication)
and in the large-cell NSCLC cell line, NCI H661 (data
not shown). Similar results have been obtained for
SEMA3B in lung carcinoma cell lines [47]. Furthermore a recent study indicates that SEMA3F suppresses
tumour formation in inducible clones in vitro and in
vivo in nude mice and reduces apoptosis. Interestingly
a SCLC cell line was resistant to SEMA3F-induced
tumour suppression [48]. However, the consequence
of high SEMA3F expression in addition to VEGF
in some cell clusters is hard to predict as a balance
between SEMA3A and VEGF modulates not only
apoptotic process but also cellular motility [32]. One
hypothesis is that VEGF might protect against death
induced by SEMA3F upregulation in migrating cells.
In summary, the VEGF/SEMA3F/NP pathway
appears to be commonly deregulated in lung cancer
pathogenesis. Loss of SEMA3F surface staining is
an early event and the degree of loss correlates with
tumour stage. VEGF staining increases progressively
with worsening dysplasia and focal areas of individual
cells or clusters staining positively for VEGF can be
detected even in low-grade dysplasias. Increased NP
staining occurs in conjunction with increased VEGF.
Based on our current understanding of this system,
we would anticipate that semaphorin replacement
combined with anti-VEGF approaches should be
additive or even synergistic in the treatment of
established tumours, as previously inferred [48].
Because alterations in VEGF/SEMA3F/NP pathway
occur early, targeted therapies should also be
advantageous for premalignant lesions.
Acknowledgements
We are very grateful to Dr Kolodkin for providing us with the
neuropilin antibodies. We thank Anne Cantereau for technical
assistance in the confocal microscopy studies performed in
the confocal microscopy core of the Research Federative
Institute IFR59 at the University of Poitiers. The following
sponsors are acknowledged: INSERM, Ligue Nationale contre
le Cancer, and ARC (S. L. and E. B.), CNRS, ARC, and Ligue
contre le Cancer (Comité de la Vienne et de la Charente)
(J. R.), University of Colorado Lung Cancer SPORE CA518707 (H. D).
References
1. Souhami R. Lung cancer. Br Med J 1992; 304: 1298–1301.
2. Gazdar A. The molecular and cellular basis of human lung cancer.
Anticancer Res 1994; 13: 561–568.
3. Travis WD, Colby TV, Corrin B, Shimosato Y, Brambilla E, in
collaboration with Sobin LH and pathologists from 14 countries.
International Histological Classification of Tumors: World Health
Organization (3rd edn). Springer: Berlin, 1999.
J Pathol 2003; 200: 336–347.
346
4. Vogelstein B, Kinzler KW. The multistep nature of cancer. Trends
Genet 1993; 9: 138–141.
5. Auerbach O, Hammond EC, Garfinkel I. Changes in bronchial
epithelium in relation to cigarette smoking 1955–1060 vs
1970–1977. N Engl J Med 1979; 300: 381–386.
6. Brambilla E, Gazzeri S, Lantuejoul S, et al. p53 mutant immunophenotype and deregulation of p53 transcription pathway (Bcl2,
Bax, and Waf1) in precursor bronchial lesions of lung cancer. Clin
Cancer Res 1998; 4: 1609–1618.
7. Lonardo F, Rush V, Langenfeld J, Dmitrovsky E, Klimstra DS.
Overexpression of cyclins D1 and E is frequent in bronchial
preneoplasia and precedes squamous cell carcinoma development.
Cancer Res 1999; 15: 2470–2476.
8. Brambilla E, Gazzeri S, Moro D, Lantuejoul S, Veyrenc S,
Brambilla C. Alterations of Rb pathway (Rb-p16INK4-cyclin
D1) in preinvasive bronchial lesions. Clin Cancer Res 1999; 5:
243–250.
9. Siemeister G, Martigny-Baron G, Marme D. The pivotal role of
VEGF in tumor angiogenesis: molecular facts and therapeutic
opportunities. Cancer Metastasis 1998; 17: 241–248.
10. Kim KJ, Li B, Winer J, et al. Inhibition of vascular endothelial
growth factor-induced angiogenesis suppresses tumour growth in
vivo. Nature 1993; 362: 841–844.
11. Fontanini G, Calcinai A, Boldrini L, et al. Modulation of
neoangiogenesis in bronchial preneoplastic lesions. Oncol Rep
1999; 6: 813–817.
12. Keith RL, Miller YE, Gemmill RM, et al. Angiogenic squamous
dysplasia in bronchi of individuals at high risk for lung cancer.
Clin Cancer Res 2000; 6: 1616–1625.
13. Kolodkin AL, Levengood D, Rowe E, Tai Y, Giger R, Ginty D.
Neuropilin is a semaphorin III receptor. Cell 1997; 90: 753–762.
14. He Z, Tessier-Lavigne M. Neuropilin is a receptor for the axonal
chemorepellent semaphorin III. Cell 1997; 90: 739–751.
15. Unified nomenclature for the semaphorins/collapsins: Semaphorin
Nomenclature Committee. Cell 1999; 97: 551–552.
16. Soker S, Takashima S, Miao HQ, Neufeld G, Klagsbrun M.
Neuropilin-1 is expressed by endothelial and tumor cells as an
isoform-specific receptor for vascular endothelial growth factor.
Cell 1998; 92: 735–745.
17. Miao HQ, Lee P, Lin H, Soker S, Klagsbrun M. Neuropilin-1
expression by tumor cells promotes tumor angiogenesis and
progression. FASEB J 2000; 14: 2532–2539.
18. Decaussin M, Sartelet H, Robert C, et al. Expression of vascular
endothelial growth factor (VEGF) and its two receptors (VEGFR1-Flt1 and VEGF-R2-Flk1/KDR) in non small cell lung
carcinomas (NSCLCs): correlation with angiogenesis and survival.
J Pathol 1999; 188: 369–377.
19. Tian X, Song S, Wu J, Meng L, Dong Z, Shou C. Vascular
endothelial growth factor: acting as an autocrine growth factor for
human gastric adenocarcinoma cell MGC803. Biochem Biophys
Res Commun 2001; 286: 505–512.
20. Chen H, Chedotal A, He Z, Goodman CS, Tessier-Lavigne M.
Neuropilin-2, a novel member of the neuropilin family, is a high
affinity receptor for the semaphorins SemaE and SemaIV but not
SemaIII. Neuron 1997; 19: 547–559.
21. Handa A, Tokunaga T, Tsuchida T, et al. Neuropilin-2 expression
affects the increased vascularization and is a prognostic factor in
osteosarcoma. Int J Oncol 2000; 17: 291–295.
22. Lacal PM, Faila CM, Pagani E, et al. Human melanoma cells
secrete and respond to placenta growth factor and vascular
endothelial growth factor. J Invest Dermatol 2000; 115:
1000–1007.
23. Kagoshima M, Ito T, Kitamura H, Goshima Y. Diverse gene
expression and function of semaphorins in developing lung:
positive and negative regulatory roles of semaphorins in lung
branching and morphogenesis. Genes Cells 2001; 6: 559–571.
24. Christensen CR, Klingelhofer J, Tarabykina S, Hulgaard EF,
Kramerov D, Lukanidin E. Transcription of a novel mouse semaphorin gene, M-semaH, correlates with the metastatic ability of
mouse tumor cell lines. Cancer Res 1998; 58: 1238–1244.
25. Brambilla E, Constantin B, Drabkin H, Roche J. Semaphorin
SEMA3F localization in malignant human lung and cell lines: a
Copyright 2003 John Wiley & Sons, Ltd.
S Lantuéjoul et al
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
suggested role in cell adhesion and migration. Am J Pathol 2000;
156: 939–950.
Sekido Y, Bader S, Latif F, et al. Human semaphorins A (V) and
(IV) reside in the 3p21.3 small cell lung cancer deletion region
and demonstrate distinct expression patterns. Proc Natl Acad Sci
USA 1996; 93: 4120–4125.
Roche J, Boldog F, Robinson M, et al. Distinct 3p21.3 deletions
in lung cancer and identification of a new human semaphorin.
Oncogene 1996; 12: 1289–1297.
Chen H, He Z, Bagri A, Tessier-Lavigne M. Semaphorin–neuropilin interactions underlying sympathetic axon to class III semaphorins. Neuron 1998; 21: 1283–1290.
Takahashi T, Fournier A, Nakamura F, et al. Plexin–neuropilin-1
complexes from functional semaphorin-3A receptors. Cell 1999;
99: 59–69.
Miao HQ, Soker S, Feiner L, Alonso JL, Raper JA, Klagsbrun M.
Neuropilin-1 mediates collapsin-1/semaphorin III inhibition of
endothelial cell motility: functional competition of collapsin-1 and
vascular endothelial growth factor-165. J Cell Biol 1999; 146:
233–242.
Giger RJ, Urquart ER, Gillespie SKH, Levengood DV, Ginty DD,
Kolodkin AL. Neuropilin-2 is a receptor for semaphorin IV:
insight into the structural basis of receptor function and specificity.
Neuron 1998; 21: 1079–1092.
Bagnard D, Vaillant C, Khuth ST, et al. Semaphorin 3A-vascular
endothelial growth factor-165 balance mediates migration and
apoptosis of neural progenitor cells by the recruitment of shared
receptor. J Neurosci 2001; 21: 3332–3341.
Hirsch E, Hu L-J, Prigent A, et al. Distribution of semaphorin IV
in adult human brain. Brain Res 1999; 823: 67–79.
Dobbs SP, Hewette PW, Johnson IR, Carmichael J, Murray JC.
Angiogenesis is associated with vascular endothelial growth factor
expression in cervical intraepithelial neoplasia. Br J Cancer 1997;
76: 1410–1415.
Herold-Mende C, Steiner HH, Andl T, et al. Expression and
functional significance of vascular endothelial growth factor
receptors in human tumor cells. Lab Invest 1999; 79: 1573.
Denhart BC, Guidi AJ, Tognazzi K, Dvorak HF, Brown LF.
Vascular permeability factor/vascular endothelial growth factor and
its receptors in oral and laryngeal squamous cell carcinoma and
dysplasia. Lab Invest 1997; 6: 659–664.
Heeschen C, Jang JJ, Weis M, et al. Nicotine stimulates angiogenesis and promotes tumor growth and atherosclerosis. Nat Med
2001; 7: 833–839.
Bachelder R, Crago A, Chung J, et al. Vascular endothelial growth
factor is an autocrine survival factor for neuropilin-expressing
breast carcinoma cells. Cancer Res 2001; 61: 5736–5740.
Byzova TV, Goldman CK, Pampori N, et al. A mechanism for
modulation of cellular responses to VEGF: activation of the
integrins. Mol Cell 2000; 6: 851–860.
Price DJ, Miralem T, Jiang S, Steinberg R, Avraham H. Role of
vascular endothelial growth factor in the stimulation of cellular
invasion and signaling of breast cancer cells. Cell Growth Diff
2001; 12: 129–135.
Barr LF, Campbell SE, Diette GB, et al. C-Myc suppresses the
tumorigenicity of lung cancer cells and down regulates vascular
endothelial growth factor expression. Cancer Res 2000; 60:
143–149.
Wistuba II, Behrens C, Virmani AK, et al. High resolution chromosome 3p allelotyping of human cancer and preneoplastic/preinvasive bronchial epithelium reveals multiple, discontinuous sites of 3p allele loss and three regions of frequent breakpoints.
Cancer Res 2000; 60: 1949–1960.
Shi JY, Yang SC, Hong TM, et al. Collapsin response mediator
protein-1 and the invasion and metastasis of cancer cells. J Natl
Cancer Inst 2001; 93: 1392–1400.
Latil A, Bieche I, Pesche S, et al. VEGF overexpression in clinically localized prostate tumors and neuropilin-1 overexpression in
metastatic forms. Int J Cancer 2000; 89: 167–172.
Ding H, Wu X, Roncari L, et al. Expression and regulation of
neuropilin-1 in human astrocytomas. Int J Cancer 2000; 88:
584–592.
J Pathol 2003; 200: 336–347.
VEGF, semaphorin, and neuropilins in lung tumours
46. Oh H, Takagi H, Otani A, et al. Selective induction of neuropilin1 by vascular endothelial growth factor (VEGF): a mechanism
contributing to VEGF- induced angiogenesis. Proc Natl Acad Sci
USA 2002; 99: 383–388.
47. Tomizawa Y, Sekido Y, Kondo M, et al. Inhibition of lung cancer
cell growth and induction of apoptosis following re-expression of
Copyright 2003 John Wiley & Sons, Ltd.
347
3p21.1 candidate tumor suppressor gene SEMA3B. Proc Natl Acad
Sci USA 2001; 98: 13954–13959.
48. Xiang R, Davalos AR, Hensel CH, Zhou XJ, Tse C, Naylor
SL. Semaphorin 3F gene from human 3p21.3 suppresses
tumor formation in nude mice. Cancer Res 2002; 62:
2637–2643.
J Pathol 2003; 200: 336–347.