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Vincent Potiron - One of the best experts on this subject based on the ideXlab platform.
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zeb 1 a repressor of the semaphorin 3f tumor suppressor gene in lung cancer cells
Neoplasia, 2009Co-Authors: Jonathan Clarhaut, Harry A Drabkin, Robert M Gemmill, Vincent Potiron, Slimane Aitsiali, Jean Imbert, Joëlle RocheAbstract:SEMA3F is a secreted semaphorin with potent antitumor activity, which is frequently downregulated in lung cancer. In cancer cell lines, SEMA3F overexpression decreases hypoxia-induced factor 1alpha protein and vascular endothelial growth factor mRNA, and inhibits multiple signaling components. Therefore, understanding how SEMA3F expression is inhibited in cancer cells is important. We previously defined the promoter organization of SEMA3F and found that chromatin remodeling by a histone deacetylase inhibitor was sufficient to activate SEMA3F expression. In lung cancer, we have also shown that ZEB-1, an E-box transcription repressor, is predominantly responsible for loss of E-Cadherin associated with a poor prognosis and resistance to epidermal growth factor receptor inhibitors. In the present study, we demonstrated that ZEB-1 also inhibits SEMA3F in lung cancer cells. Levels of ZEB-1, but not ZEB-2, Snail or Slug, significantly correlate with SEMA3F inhibition, and overexpression or inhibition of ZEB-1 correspondingly affected SEMA3F expression. Four conserved E-box sites were identified in the SEMA3F gene. Direct ZEB-1 binding was confirmed by chromatin immunoprecipitation assays for two of these, and ZEB-1 binding was reduced when cells were treated with a histone deacetylase inhibitor. These results demonstrate that ZEB-1 directly inhibits SEMA3F expression in lung cancer cells. SEMA3F loss was associated with changes in cell signaling: increased phospho-AKT in normoxia and increase of hypoxia-induced factor 1alpha protein in hypoxia. Moreover, exogenous addition of SEMA3F could modulate ZEB-1-induced angiogenesis in a chorioallantoic membrane assay. Together, these data provide further support for the importance of SEMA3F and ZEB-1 in lung cancer progression.
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etude des mecanismes moleculaires responsables de la fonction anti tumorale de la semaphorine SEMA3F dans le cancer broncho pulmonaire
2007Co-Authors: Vincent PotironAbstract:La semaphorine SEMA3F est une proteine de guidage axonal egalement impliquee dans l'angiogenese. Le gene SEMA3F est situe dans une region de perte d'heterozygotie dans les tumeurs pulmonaires chez l'homme, suggerant un role anti-tumoral. Nous avons tout d'abord developpe un modele animal de cancer pulmonaire chez le rat en injectant des cellules tumorales pulmonaires transfectees avec SEMA3F. Ce modele a permis de demontrer un pouvoir anti-tumoral de SEMA3F. De plus, nous avons analyse les mecanismes moleculaires qui expliqueraient le pouvoir anti-tumoral de SEMA3F. Nos resultats, bases sur une lignee cellulaire cancereurese pulmonaire (H157), indiquent que SEMA3F inhibe l'activation de l'integrine alphaV beta3, de la voie ILK-ERK1/2, de AKT et de STAT3. SEMA3F inhibe aussi l'expression de HIF-1 alpha et du VEGF, ce qui pourrait etre a l'origine des effets anti-angiogeniques que nous avons observes dans un modele de tumorigenese sous-cutanee chez la souris ainsi que dans un modele d'angiogenese chez le poulet in ovo. Nos resultats montrent que SEMA3F bloque le developpement tumoral pulmonaire, probablement en affectant des voies de signalisation intracellulaire participant a l'angiogenese tumorale.
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Semaphorin SEMA3F affects multiple signaling pathways in lung cancer cells
Cancer Research, 2007Co-Authors: Vincent Potiron, Joëlle Roche, Jonathan Clarhaut, Robert M Gemmill, Patrick Nasarre, Girish Sharma, Hellmut Augustin, Harry DrakkinAbstract:Loss of SEMA3F occurs frequently in lung cancer and correlates with advanced stage of disease. We previously reported that SEMA3F blocked tumor formation by H157 lung cancer cells in a rat orthotopic model. This was associated with loss of activated alpha(V)beta(3) integrin, impaired cell adhesion to extracellular matrix components, and down-regulation of phospho-extracellular signal-regulated kinase 1/2 (ERK1/2). These results suggested that SEMA3F might interfere with integrin outside-in signaling. In the present report, we found that SEMA3F decreased adhesion to vitronectin, whereas integrin-linked kinase (ILK) kinase activity was down-regulated in SEMA3F-expressing H157 cells. Exposure to SEMA3F-conditioned medium led to diminution of phospho-ERK1/2 in four of eight lung cancer cell lines, and ILK silencing by small interfering RNA led to similar loss of phospho-ERK1/2 in H157 cells. Moreover, SEMA3F expression (with constitutive and inducible systems) also reduced AKT and signal transducer and activator of transcription 3 (STAT3) phosphorylation independently of ILK-ERK1/2. These signaling changes extended downstream to hypoxia-inducible factor-1alpha (HIF-1alpha) protein and vascular endothelial growth factor (VEGF) mRNA levels, which were both reduced in three of four SEMA3F-transfected cell lines. Mechanistically, the effects on HIF-1alpha were consistent with inhibition of its AKT-driven protein translation initiation, with no effect on HIF-1alpha mRNA level or protein degradation. Furthermore, when H157 cells were injected s.c. in nude mice, tumors derived from SEMA3F-expressing cells showed lower microvessel density and tumor growth. These results show that SEMA3F negatively affects ILK-ERK1/2 and AKT-STAT3 signaling, along with inhibition of HIF-1alpha and VEGF. These changes would be anticipated to contribute significantly to the observed antitumor activity of SEMA3F.
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promoter characterization of semaphorin SEMA3F a tumor suppressor gene
Biochimica et Biophysica Acta, 2005Co-Authors: Sophie Kusy, Harry A Drabkin, John D Minna, Vincent Potiron, Chan Zeng, Wilbur A Franklin, Elisabeth Brambilla, Joëlle RocheAbstract:The tumor suppressor gene, Semaphorin SEMA3F, is frequently downregulated in lung cancer. Understanding the specific mechanism of SEMA3F suppression should be informative in terms of epithelial carcinogenesis and potential therapeutic interventions. Although a CpG-island is located 5083-3927 nt upstream of the translation start site, there have been no previous reports dealing with SEMA3F promoter regulation. We have now mapped the transcriptional initiation sites within the CpG-island and defined the region necessary for transcriptional activation. We then looked for evidence of SEMA3F promoter methylation since SEMA3F mutations are rare. By Southern blot and methylation-specific PCR assays, we identified a region in cell lines (i.e., area d at position minus 3850-3644 nt) for which methylation was significantly (P<0.0001) correlated with loss of expression. However, histone deacetylase inhibition with Trichostatin A was much more effective than 5-aza-2'-deoxycytidine in stimulating SEMA3F. Our results suggest that while SEMA3F promoter methylation correlates with repression, chromatin remodeling through histone deacetylase inhibition is sufficient to activate SEMA3F expression.
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selective suppression of in vivo tumorigenicity by semaphorin SEMA3F in lung cancer cells
Neoplasia, 2005Co-Authors: Robert M Gemmill, Vincent Potiron, Sophie Kusy, Patrick Nasarre, Daniel Chan, David Meyronet, Bruno Constantin, Harry A DrabkinAbstract:Loss of the 3p21.3-encoded semaphorins, SEMA3B and SEMA3F is implicated in lung cancer development. Although both antagonize VEGF binding/response to neuropilin (NRP) receptors, in lung cancer lines,SEMA3F is predominantly expressed and preferentially utilizes NRP2. In lung cancer patients, SEMA3F loss correlates with advanced disease and increased VEGF binding to tumor cells. In cell lines, VEGF enhances adhesion and migration in an integrin-dependent manner, and exogenous SEMA3F causes cells to round and lose extracellular contacts. Using retroviral infections, we established stable SEMA3F transfectants in two NSCLC cell lines, NCI-H157 and NCI-H460. When orthotopically injected into nude rats, both control lines caused lethal tumors in all recipients. In contrast, all animals receiving H157-SEMA3F cells, survived to 100 days, whereas all H157 controls succumbed. In H460 cells, which express NRP1 but not NRP2, SEMA3F did not prolong survival. This antitumor effect in H157 cells was associated with loss of activated αvβ3 integrin and adhesion to extracellular matrix components. In addition, H157-SEMA3F cells, and parental H157 cells exposed to SEMA3F-conditioned medium, showed loss of p42/p44 MAPK phosphorylation. Thus, in this in vivo lung cancer model, SEMA3F has potent antitumor effects, which may impinge on activated integrin and MAPK signaling.
Sophie Kusy - One of the best experts on this subject based on the ideXlab platform.
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promoter characterization of semaphorin SEMA3F a tumor suppressor gene
Biochimica et Biophysica Acta, 2005Co-Authors: Sophie Kusy, Harry A Drabkin, John D Minna, Vincent Potiron, Chan Zeng, Wilbur A Franklin, Elisabeth Brambilla, Joëlle RocheAbstract:The tumor suppressor gene, Semaphorin SEMA3F, is frequently downregulated in lung cancer. Understanding the specific mechanism of SEMA3F suppression should be informative in terms of epithelial carcinogenesis and potential therapeutic interventions. Although a CpG-island is located 5083-3927 nt upstream of the translation start site, there have been no previous reports dealing with SEMA3F promoter regulation. We have now mapped the transcriptional initiation sites within the CpG-island and defined the region necessary for transcriptional activation. We then looked for evidence of SEMA3F promoter methylation since SEMA3F mutations are rare. By Southern blot and methylation-specific PCR assays, we identified a region in cell lines (i.e., area d at position minus 3850-3644 nt) for which methylation was significantly (P<0.0001) correlated with loss of expression. However, histone deacetylase inhibition with Trichostatin A was much more effective than 5-aza-2'-deoxycytidine in stimulating SEMA3F. Our results suggest that while SEMA3F promoter methylation correlates with repression, chromatin remodeling through histone deacetylase inhibition is sufficient to activate SEMA3F expression.
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selective suppression of in vivo tumorigenicity by semaphorin SEMA3F in lung cancer cells
Neoplasia, 2005Co-Authors: Robert M Gemmill, Vincent Potiron, Sophie Kusy, Patrick Nasarre, Daniel Chan, David Meyronet, Bruno Constantin, Harry A DrabkinAbstract:Loss of the 3p21.3-encoded semaphorins, SEMA3B and SEMA3F is implicated in lung cancer development. Although both antagonize VEGF binding/response to neuropilin (NRP) receptors, in lung cancer lines,SEMA3F is predominantly expressed and preferentially utilizes NRP2. In lung cancer patients, SEMA3F loss correlates with advanced disease and increased VEGF binding to tumor cells. In cell lines, VEGF enhances adhesion and migration in an integrin-dependent manner, and exogenous SEMA3F causes cells to round and lose extracellular contacts. Using retroviral infections, we established stable SEMA3F transfectants in two NSCLC cell lines, NCI-H157 and NCI-H460. When orthotopically injected into nude rats, both control lines caused lethal tumors in all recipients. In contrast, all animals receiving H157-SEMA3F cells, survived to 100 days, whereas all H157 controls succumbed. In H460 cells, which express NRP1 but not NRP2, SEMA3F did not prolong survival. This antitumor effect in H157 cells was associated with loss of activated αvβ3 integrin and adhesion to extracellular matrix components. In addition, H157-SEMA3F cells, and parental H157 cells exposed to SEMA3F-conditioned medium, showed loss of p42/p44 MAPK phosphorylation. Thus, in this in vivo lung cancer model, SEMA3F has potent antitumor effects, which may impinge on activated integrin and MAPK signaling.
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Semaphorin SEMA3F has a repulsing activity on breast cancer cells and inhibits E-cadherin-mediated cell adhesion.
Neoplasia : An International Journal for Oncology Research, 2005Co-Authors: Patrick Nasarre, Harry A Drabkin, Dominique Bagnard, Sophie Kusy, Bruno Constantin, Valérie Castellani, Joëlle RocheAbstract:Previously, we demonstrated that loss of SEMA3F, a secreted semaphorin encoded in 3p21.3, is associated with higher stages in lung cancer and primary tumor cells studied with anti-vascular endothelial growth factor (VEGF) and SEMA3F antibodies. In vitro, SEMA3F inhibits cell spreading; this activity is opposed by VEGF. These results suggest that VEGF and SEMA3F compete for binding to their common neuropilin receptor. In the present report, we investigated the attractive/repulsive effects of SEMA3F on cell migration when cells were grown in a three-dimensional system and exposed to a SEMA3F gradient. In addition, we adapted the neurobiologic stripe assay to analyze the migration of tumor cells in response to SEMA3F. In the motile breast cancer cell line C100, which expresses both neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors, SEMA3F had a repulsive effect, which was blocked by anti-NRP2 antibody. In less motile MCF7 cells, which express only NRP1, SEMA3F inhibited cell contacts with loss of membrane-associated E-cadherin and beta-catenin without motility induction. Cell spreading and proliferation were reduced. These results support the concept that in a first step during tumorigenesis, normal tissues expressing SEMA3F would try to prevent tumor cells from spreading and attaching to the stroma for further implantation.
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regulation de l expression et fonction anti tumorale de la semaphorine SEMA3F
2005Co-Authors: Sophie KusyAbstract:Notre groupe a clone en 3p21. 3 un gene codant pour la semaphorine SEMA3F. C'est une proteine secretee impliquee initialement dans la migration cellulaire. Nos objectifs etaient d'etudier la regulation de l'expression de SEMA3F et de verifier son role anti-tumoral chez l'animal. Nous avons etabli la carte du promoteur de SEMA3F, identifie de multiples sites d'initiation de la transcription dans un ilot CpG et isole une region necessaire a l'expression. La methylation de SEMA3F et le remodelage de la chromatine interviennent dans cette regulation. Nous avons aussi determine le profil d'expression et les proprietes biologiques des 2 formes epissees de SEMA3F durant la maturation du systeme nerveux murin. Malgre des fonctions redondantes, ces isoformes subissent une regulation temporelle et regionale. Enfin, nous avons decrit l'activite anti-tumorale de SEMA3F dans le poumon de rats immunodeficients. La neuropiline 2, les integrines et les MAPKinases semblent impliquees dans ce phenomene.
Gera Neufeld - One of the best experts on this subject based on the ideXlab platform.
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The role of the plexin-A2 receptor in Sema3A and Sema3B signal transduction.
Journal of Cell Science, 2014Co-Authors: Adi D. Sabag, Ofra Kessler, Gera Neufeld, Tatyana Smolkin, Yelena Mumblat, Marius Ueffing, Christian Johannes GloecknerAbstract:Class 3 semaphorins are anti-angiogenic and anti-tumorigenic guidance factors that bind to neuropilins, which, in turn, associate with class A plexins to transduce semaphorin signals. To study the role of the plexin-A2 receptor in semaphorin signaling, we silenced its expression in endothelial cells and in glioblastoma cells. The silencing did not affect Sema3A signaling, which depended on neuropilin-1, plexin-A1 and plexin-A4, but completely abolished Sema3B signaling, which also required plexin-A4 and one of the two neuropilins. Interestingly, overexpression of plexin-A2 in plexin-A1- or plexin-A4-silenced cells restored responses to both semaphorins, although it nullified their ability to differentiate between them, suggesting that, when overexpressed, plexin-A2 can functionally replace other class A plexins. By contrast, although plexin-A4 overexpression restored Sema3A signaling in plexin-A1-silenced cells, it failed to restore Sema3B signaling in plexin-A2-silenced cells. It follows that the identity of plexins in functional semaphorin receptors can be flexible depending on their expression level. Our results suggest that changes in the expression of plexins induced by microenvironmental cues can trigger differential responses of different populations of migrating cells to encountered gradients of semaphorins.
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successful inhibition of tumor development by specific class 3 semaphorins is associated with expression of appropriate semaphorin receptors by tumor cells
PLOS ONE, 2008Co-Authors: Boaz Kigel, Ofra Kessler, Asya Varshavsky, Gera NeufeldAbstract:The class-3 semaphorins (sema3s) include seven family members. Six of them bind to neuropilin-1 (np1) or neuropilin-2 (np2) receptors or to both, while the seventh, sema3E, binds to the plexin-D1 receptor. Sema3B and SEMA3F were previously characterized as tumor suppressors and as inhibitors of tumor angiogenesis. To determine if additional class-3 semaphorins such as sema3A, sema3D, sema3E and sema3G possess anti-angiogenic and anti-tumorigenic properties, we expressed the recombinant full length semaphorins in four different tumorigenic cell lines expressing different combinations of class-3 semaphorin receptors. We show for the first time that sema3A, sema3D, sema3E and sema3G can function as potent anti-tumorigenic agents. All the semaphorins we examined were also able to reduce the concentration of tumor associated blood vessels although the potencies of the anti-angiogenic effects varied depending on the tumor cell type. Surprisingly, there was little correlation between the ability to inhibit tumor angiogenesis and their anti-tumorigenic activity. None of the semaphorins inhibited the adhesion of the tumor cells to plastic or fibronectin nor did they modulate the proliferation of tumor cells cultured in cell culture dishes. However, various semaphorins were able to inhibit the formation of soft agar colonies from tumor cells expressing appropriate semaphorin receptors, although in this case too the inhibitory effect was not always correlated with the anti-tumorigenic effect. In contrast, the anti-tumorigenic effect of each of the semaphorins correlated very well with tumor cell expression of specific signal transducing receptors for particular semaphorins. This correlation was not broken even in cases in which the tumor cells expressed significant concentrations of endogenous semaphorins. Our results suggest that combinations of different class-3 semaphorins may be more effective than single semaphorins in cases in which tumor cells express more than one type of semaphorin receptors.
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semaphorin 3a and semaphorin 3f work together to repel endothelial cells and to inhibit their survival by induction of apoptosis
Journal of Biological Chemistry, 2007Co-Authors: Noga Guttmannraviv, Ofra Kessler, Gera Neufeld, Asya Varshavsky, Niva Shragaheled, Cinthya GuimaraessternbergAbstract:Abstract Semaphorin-3A (sema3A) is a neuropilin-1 (np1) agonist. It inhibits the binding of the 165-amino acid form of VEGF (VEGF165) to np1 and was reported to inhibit angiogenesis as a result. However, we find that sema3A concentrations that inhibit the mitogenic effects of VEGF165 do not inhibit VEGF165-induced phosphorylation of VEGF receptor-2 (VEGFR-2). Furthermore, sema3A inhibits the biological effects of VEGF121, a VEGF form that does not bind to neuropilins and basic fibroblast growth factor, a growth factor whose activity, unlike that of VEGF, is not inhibited by small interfering RNA directed against np1. Therefore, the mechanism by which sema3A inhibits VEGF165 activity does not depend on competition with VEGF165 for binding to np1. Sema3A induced rapid disappearance of focal contacts followed by collapse of the actin cytoskeleton in human umbilical vein-derived endothelial cells. HEK293 cells expressing sema3A repel human endothelial cells and at high concentrations induce their death by apoptosis. Furthermore, sema3A inhibited the formation of tubes from endothelial cells in an in vitro angiogenesis assay. Similar effects are induced by the neuropilin-2 (np2) agonist SEMA3F. These inhibitory effects are abrogated by small interfering RNAs directed against np1 or np2, respectively. The anti-proliferative effects of sema3A and SEMA3F are additive when the semaphorins are added as pure proteins. However, when sema3A and SEMA3F were co-expressed in HEK293 cells their pro-apoptotic and cell repellant activities appeared to be synergistic. These observations suggest that combinations of sema3A and SEMA3F may be able to inhibit tumor angiogenesis more effectively than single semaphorins.
Joëlle Roche - One of the best experts on this subject based on the ideXlab platform.
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zeb 1 a repressor of the semaphorin 3f tumor suppressor gene in lung cancer cells
Neoplasia, 2009Co-Authors: Jonathan Clarhaut, Harry A Drabkin, Robert M Gemmill, Vincent Potiron, Slimane Aitsiali, Jean Imbert, Joëlle RocheAbstract:SEMA3F is a secreted semaphorin with potent antitumor activity, which is frequently downregulated in lung cancer. In cancer cell lines, SEMA3F overexpression decreases hypoxia-induced factor 1alpha protein and vascular endothelial growth factor mRNA, and inhibits multiple signaling components. Therefore, understanding how SEMA3F expression is inhibited in cancer cells is important. We previously defined the promoter organization of SEMA3F and found that chromatin remodeling by a histone deacetylase inhibitor was sufficient to activate SEMA3F expression. In lung cancer, we have also shown that ZEB-1, an E-box transcription repressor, is predominantly responsible for loss of E-Cadherin associated with a poor prognosis and resistance to epidermal growth factor receptor inhibitors. In the present study, we demonstrated that ZEB-1 also inhibits SEMA3F in lung cancer cells. Levels of ZEB-1, but not ZEB-2, Snail or Slug, significantly correlate with SEMA3F inhibition, and overexpression or inhibition of ZEB-1 correspondingly affected SEMA3F expression. Four conserved E-box sites were identified in the SEMA3F gene. Direct ZEB-1 binding was confirmed by chromatin immunoprecipitation assays for two of these, and ZEB-1 binding was reduced when cells were treated with a histone deacetylase inhibitor. These results demonstrate that ZEB-1 directly inhibits SEMA3F expression in lung cancer cells. SEMA3F loss was associated with changes in cell signaling: increased phospho-AKT in normoxia and increase of hypoxia-induced factor 1alpha protein in hypoxia. Moreover, exogenous addition of SEMA3F could modulate ZEB-1-induced angiogenesis in a chorioallantoic membrane assay. Together, these data provide further support for the importance of SEMA3F and ZEB-1 in lung cancer progression.
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Semaphorin SEMA3F affects multiple signaling pathways in lung cancer cells
Cancer Research, 2007Co-Authors: Vincent Potiron, Joëlle Roche, Jonathan Clarhaut, Robert M Gemmill, Patrick Nasarre, Girish Sharma, Hellmut Augustin, Harry DrakkinAbstract:Loss of SEMA3F occurs frequently in lung cancer and correlates with advanced stage of disease. We previously reported that SEMA3F blocked tumor formation by H157 lung cancer cells in a rat orthotopic model. This was associated with loss of activated alpha(V)beta(3) integrin, impaired cell adhesion to extracellular matrix components, and down-regulation of phospho-extracellular signal-regulated kinase 1/2 (ERK1/2). These results suggested that SEMA3F might interfere with integrin outside-in signaling. In the present report, we found that SEMA3F decreased adhesion to vitronectin, whereas integrin-linked kinase (ILK) kinase activity was down-regulated in SEMA3F-expressing H157 cells. Exposure to SEMA3F-conditioned medium led to diminution of phospho-ERK1/2 in four of eight lung cancer cell lines, and ILK silencing by small interfering RNA led to similar loss of phospho-ERK1/2 in H157 cells. Moreover, SEMA3F expression (with constitutive and inducible systems) also reduced AKT and signal transducer and activator of transcription 3 (STAT3) phosphorylation independently of ILK-ERK1/2. These signaling changes extended downstream to hypoxia-inducible factor-1alpha (HIF-1alpha) protein and vascular endothelial growth factor (VEGF) mRNA levels, which were both reduced in three of four SEMA3F-transfected cell lines. Mechanistically, the effects on HIF-1alpha were consistent with inhibition of its AKT-driven protein translation initiation, with no effect on HIF-1alpha mRNA level or protein degradation. Furthermore, when H157 cells were injected s.c. in nude mice, tumors derived from SEMA3F-expressing cells showed lower microvessel density and tumor growth. These results show that SEMA3F negatively affects ILK-ERK1/2 and AKT-STAT3 signaling, along with inhibition of HIF-1alpha and VEGF. These changes would be anticipated to contribute significantly to the observed antitumor activity of SEMA3F.
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promoter characterization of semaphorin SEMA3F a tumor suppressor gene
Biochimica et Biophysica Acta, 2005Co-Authors: Sophie Kusy, Harry A Drabkin, John D Minna, Vincent Potiron, Chan Zeng, Wilbur A Franklin, Elisabeth Brambilla, Joëlle RocheAbstract:The tumor suppressor gene, Semaphorin SEMA3F, is frequently downregulated in lung cancer. Understanding the specific mechanism of SEMA3F suppression should be informative in terms of epithelial carcinogenesis and potential therapeutic interventions. Although a CpG-island is located 5083-3927 nt upstream of the translation start site, there have been no previous reports dealing with SEMA3F promoter regulation. We have now mapped the transcriptional initiation sites within the CpG-island and defined the region necessary for transcriptional activation. We then looked for evidence of SEMA3F promoter methylation since SEMA3F mutations are rare. By Southern blot and methylation-specific PCR assays, we identified a region in cell lines (i.e., area d at position minus 3850-3644 nt) for which methylation was significantly (P<0.0001) correlated with loss of expression. However, histone deacetylase inhibition with Trichostatin A was much more effective than 5-aza-2'-deoxycytidine in stimulating SEMA3F. Our results suggest that while SEMA3F promoter methylation correlates with repression, chromatin remodeling through histone deacetylase inhibition is sufficient to activate SEMA3F expression.
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Semaphorin SEMA3F has a repulsing activity on breast cancer cells and inhibits E-cadherin-mediated cell adhesion.
Neoplasia : An International Journal for Oncology Research, 2005Co-Authors: Patrick Nasarre, Harry A Drabkin, Dominique Bagnard, Sophie Kusy, Bruno Constantin, Valérie Castellani, Joëlle RocheAbstract:Previously, we demonstrated that loss of SEMA3F, a secreted semaphorin encoded in 3p21.3, is associated with higher stages in lung cancer and primary tumor cells studied with anti-vascular endothelial growth factor (VEGF) and SEMA3F antibodies. In vitro, SEMA3F inhibits cell spreading; this activity is opposed by VEGF. These results suggest that VEGF and SEMA3F compete for binding to their common neuropilin receptor. In the present report, we investigated the attractive/repulsive effects of SEMA3F on cell migration when cells were grown in a three-dimensional system and exposed to a SEMA3F gradient. In addition, we adapted the neurobiologic stripe assay to analyze the migration of tumor cells in response to SEMA3F. In the motile breast cancer cell line C100, which expresses both neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors, SEMA3F had a repulsive effect, which was blocked by anti-NRP2 antibody. In less motile MCF7 cells, which express only NRP1, SEMA3F inhibited cell contacts with loss of membrane-associated E-cadherin and beta-catenin without motility induction. Cell spreading and proliferation were reduced. These results support the concept that in a first step during tumorigenesis, normal tissues expressing SEMA3F would try to prevent tumor cells from spreading and attaching to the stroma for further implantation.
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expression of vegf semaphorin SEMA3F and their common receptors neuropilins np1 and np2 in preinvasive bronchial lesions lung tumours and cell lines
The Journal of Pathology, 2003Co-Authors: Sylvie Lantuejoul, Joëlle Roche, Harry A Drabkin, Bruno Constantin, C Brambilla, Elisabeth BrambillaAbstract: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.
Harry A Drabkin - One of the best experts on this subject based on the ideXlab platform.
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zeb 1 a repressor of the semaphorin 3f tumor suppressor gene in lung cancer cells
Neoplasia, 2009Co-Authors: Jonathan Clarhaut, Harry A Drabkin, Robert M Gemmill, Vincent Potiron, Slimane Aitsiali, Jean Imbert, Joëlle RocheAbstract:SEMA3F is a secreted semaphorin with potent antitumor activity, which is frequently downregulated in lung cancer. In cancer cell lines, SEMA3F overexpression decreases hypoxia-induced factor 1alpha protein and vascular endothelial growth factor mRNA, and inhibits multiple signaling components. Therefore, understanding how SEMA3F expression is inhibited in cancer cells is important. We previously defined the promoter organization of SEMA3F and found that chromatin remodeling by a histone deacetylase inhibitor was sufficient to activate SEMA3F expression. In lung cancer, we have also shown that ZEB-1, an E-box transcription repressor, is predominantly responsible for loss of E-Cadherin associated with a poor prognosis and resistance to epidermal growth factor receptor inhibitors. In the present study, we demonstrated that ZEB-1 also inhibits SEMA3F in lung cancer cells. Levels of ZEB-1, but not ZEB-2, Snail or Slug, significantly correlate with SEMA3F inhibition, and overexpression or inhibition of ZEB-1 correspondingly affected SEMA3F expression. Four conserved E-box sites were identified in the SEMA3F gene. Direct ZEB-1 binding was confirmed by chromatin immunoprecipitation assays for two of these, and ZEB-1 binding was reduced when cells were treated with a histone deacetylase inhibitor. These results demonstrate that ZEB-1 directly inhibits SEMA3F expression in lung cancer cells. SEMA3F loss was associated with changes in cell signaling: increased phospho-AKT in normoxia and increase of hypoxia-induced factor 1alpha protein in hypoxia. Moreover, exogenous addition of SEMA3F could modulate ZEB-1-induced angiogenesis in a chorioallantoic membrane assay. Together, these data provide further support for the importance of SEMA3F and ZEB-1 in lung cancer progression.
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promoter characterization of semaphorin SEMA3F a tumor suppressor gene
Biochimica et Biophysica Acta, 2005Co-Authors: Sophie Kusy, Harry A Drabkin, John D Minna, Vincent Potiron, Chan Zeng, Wilbur A Franklin, Elisabeth Brambilla, Joëlle RocheAbstract:The tumor suppressor gene, Semaphorin SEMA3F, is frequently downregulated in lung cancer. Understanding the specific mechanism of SEMA3F suppression should be informative in terms of epithelial carcinogenesis and potential therapeutic interventions. Although a CpG-island is located 5083-3927 nt upstream of the translation start site, there have been no previous reports dealing with SEMA3F promoter regulation. We have now mapped the transcriptional initiation sites within the CpG-island and defined the region necessary for transcriptional activation. We then looked for evidence of SEMA3F promoter methylation since SEMA3F mutations are rare. By Southern blot and methylation-specific PCR assays, we identified a region in cell lines (i.e., area d at position minus 3850-3644 nt) for which methylation was significantly (P<0.0001) correlated with loss of expression. However, histone deacetylase inhibition with Trichostatin A was much more effective than 5-aza-2'-deoxycytidine in stimulating SEMA3F. Our results suggest that while SEMA3F promoter methylation correlates with repression, chromatin remodeling through histone deacetylase inhibition is sufficient to activate SEMA3F expression.
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selective suppression of in vivo tumorigenicity by semaphorin SEMA3F in lung cancer cells
Neoplasia, 2005Co-Authors: Robert M Gemmill, Vincent Potiron, Sophie Kusy, Patrick Nasarre, Daniel Chan, David Meyronet, Bruno Constantin, Harry A DrabkinAbstract:Loss of the 3p21.3-encoded semaphorins, SEMA3B and SEMA3F is implicated in lung cancer development. Although both antagonize VEGF binding/response to neuropilin (NRP) receptors, in lung cancer lines,SEMA3F is predominantly expressed and preferentially utilizes NRP2. In lung cancer patients, SEMA3F loss correlates with advanced disease and increased VEGF binding to tumor cells. In cell lines, VEGF enhances adhesion and migration in an integrin-dependent manner, and exogenous SEMA3F causes cells to round and lose extracellular contacts. Using retroviral infections, we established stable SEMA3F transfectants in two NSCLC cell lines, NCI-H157 and NCI-H460. When orthotopically injected into nude rats, both control lines caused lethal tumors in all recipients. In contrast, all animals receiving H157-SEMA3F cells, survived to 100 days, whereas all H157 controls succumbed. In H460 cells, which express NRP1 but not NRP2, SEMA3F did not prolong survival. This antitumor effect in H157 cells was associated with loss of activated αvβ3 integrin and adhesion to extracellular matrix components. In addition, H157-SEMA3F cells, and parental H157 cells exposed to SEMA3F-conditioned medium, showed loss of p42/p44 MAPK phosphorylation. Thus, in this in vivo lung cancer model, SEMA3F has potent antitumor effects, which may impinge on activated integrin and MAPK signaling.
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Semaphorin SEMA3F has a repulsing activity on breast cancer cells and inhibits E-cadherin-mediated cell adhesion.
Neoplasia : An International Journal for Oncology Research, 2005Co-Authors: Patrick Nasarre, Harry A Drabkin, Dominique Bagnard, Sophie Kusy, Bruno Constantin, Valérie Castellani, Joëlle RocheAbstract:Previously, we demonstrated that loss of SEMA3F, a secreted semaphorin encoded in 3p21.3, is associated with higher stages in lung cancer and primary tumor cells studied with anti-vascular endothelial growth factor (VEGF) and SEMA3F antibodies. In vitro, SEMA3F inhibits cell spreading; this activity is opposed by VEGF. These results suggest that VEGF and SEMA3F compete for binding to their common neuropilin receptor. In the present report, we investigated the attractive/repulsive effects of SEMA3F on cell migration when cells were grown in a three-dimensional system and exposed to a SEMA3F gradient. In addition, we adapted the neurobiologic stripe assay to analyze the migration of tumor cells in response to SEMA3F. In the motile breast cancer cell line C100, which expresses both neuropilin-1 (NRP1) and neuropilin-2 (NRP2) receptors, SEMA3F had a repulsive effect, which was blocked by anti-NRP2 antibody. In less motile MCF7 cells, which express only NRP1, SEMA3F inhibited cell contacts with loss of membrane-associated E-cadherin and beta-catenin without motility induction. Cell spreading and proliferation were reduced. These results support the concept that in a first step during tumorigenesis, normal tissues expressing SEMA3F would try to prevent tumor cells from spreading and attaching to the stroma for further implantation.
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expression of vegf semaphorin SEMA3F and their common receptors neuropilins np1 and np2 in preinvasive bronchial lesions lung tumours and cell lines
The Journal of Pathology, 2003Co-Authors: Sylvie Lantuejoul, Joëlle Roche, Harry A Drabkin, Bruno Constantin, C Brambilla, Elisabeth BrambillaAbstract: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.
