Semaphorin 3F Expression Research Articles

Reverse effect of Semaphorin-3F on rituximab resistance in diffuse large B-cell lymphoma via the Hippo pathway.

Exploring the underlying mechanism of rituximab resistance is critical to improve the outcomes of patients with diffuse large B-cell lymphoma (DLBCL). Here, we tried to identify the effects of the axon guidance factor semaphorin-3F (SEMA3F) on rituximab resistance as well as its therapeutic value in DLBCL. The effects of SEMA3F on the treatment response to rituximab were investigated by gain- or loss-of-function experiments. The role of the Hippo pathway in SEMA3F-mediated activity was explored. A xenograft mouse model generated by SEMA3F knockdown in cells was used to evaluate rituximab sensitivity and combined therapeutic effects. The prognostic value of SEMA3F and TAZ (WW domain-containing transcription regulator protein 1) was examined in the Gene Expression Omnibus (GEO) database and human DLBCL specimens. We found that loss of SEMA3F was related to a poor prognosis in patients who received rituximab-based immunochemotherapy instead of chemotherapy regimen. Knockdown of SEMA3F significantly repressed the expression of CD20 and reduced the proapoptotic activity and complement-dependent cytotoxicity (CDC) activity induced by rituximab. We further demonstrated that the Hippo pathway was involved in the SEMA3F-mediated regulation of CD20. Knockdown of SEMA3F expression induced the nuclear accumulation of TAZ and inhibited CD20 transcriptional levels via direct binding of the transcription factor TEAD2 and the CD20 promoter. Moreover, in patients with DLBCL, SEMA3F expression was negatively correlated with TAZ, and patients with SEMA3F low TAZ high had a limited benefit from a rituximab-based strategy. Specifically, treatment of DLBCL cells with rituximab and a YAP/TAZ inhibitor showed promising therapeutic effects in vitro and in vivo . Our study thus defined a previously unknown mechanism of SEMA3F-mediated rituximab resistance through TAZ activation in DLBCL and identified potential therapeutic targets in patients.

Semaphorin 3F induces colorectal cancer cell chemosensitivity by promoting P27 nuclear export.

Colorectal adenocarcinoma (CRC) is the third most common malignancy worldwide. Metastatic CRC has a poor prognosis because of chemotherapy resistance. Our previous study demonstrated that semaphorin 3F (SEMA3F) signaling may contribute to reversing chemotherapy resistance in CRC cells by reducing E-cadherin and integrin αvβ3 expression levels. Another study showed that upregulation of p27 significantly increase the expression of E-cadherin and integrin. This study aimed to evaluate the effect of SEMA3F on P27 and whether it can reverse resistance in CRC cells. We compared the chemosensitivity of human colorectal cancer cell lines with different SEMA3F expression levels to 5-Fu through cell experiment and animal experiment. Then the interaction between SEMA3F and p27 and its possible mechanism were explored by Western Blot, immunofluorescence and immunocoprecipitation. We also compared the disease-free survival of 118 CRC patients with high or low expression of SEMA3F.The results showed that overexpresstion of SEMA3F enhanced the chemotherapy sensitivity and apoptosis of CRC cells in vitro and in vivo. Among 118 postoperative CRC specimens, the disease-free survival of patients with positive SEMA3F expression was significantly longer than that with negative SEMA3F expression after adjuvant treatment. Upregulation of SEMA3F in multicellular spheroid culture (MSC) could increase p27 phosphorylation at serine 10 (Ser10), subsequently promote the cytosolic translocation of P27. Overall, our results reveal a novel molecular mechanism: SEMA3F mediates the degradation of p27 and regulates its subcellular localization to enhance chemosensitivity to 5-Fu in CRC cells, rather than inhibits p27 expression.

Semaphorin-3F/Neuropilin-2 Transcriptional Expression as a Predictive Biomarker of Occult Lymph Node Metastases in HNSCC

Simple SummaryThe presence of lymph neck node metastasis is the most important clinical prognostic factor in patients with head and neck squamous cell carcinoma. The expression of the semaphorin-3F and neuropilin-2 proteins is involved in the regulation of lymphangiogenesis. We analized the transcriptional expression of semaphorin-3F and neuropilin-2 in head and neck squamous cell carcinoma tumors of patients without clinical or radiology evidence of lymph node involvement treated with elective neck dissection. We found that patients with high semaphorin-3F and low neuropilin-2 had a lower risk of occult lymph node metastasis than the ones who had low semaphorin-3F or high semaphorin-3F and high neuropilin-2. If our results are validated, the expression of the SEMA3F-NRP2 axis could be used as a biomarker predicting the risk of occult lymph node metastasis, with elective neck dissections being indicated exclusively for patients at higher risk. The availability of a biomarker with the capacity to predict the presence of occult lymph node metastases would make it possible to avoid elective neck dissections in low-risk patients, with the consequent decrease in surgical time and morbidity of the treatment without impairing the oncologic outcome.The expression of the semaphorin-3F (SEMA3F) and neuropilin-2 (NRP2) is involved in the regulation of lymphangiogenesis. The present study analyzes the relationship between the transcriptional expression of the SEMA3F-NRP2 genes and the presence of occult lymph node metastases in patients with cN0 head and neck squamous cell carcinomas. We analyzed the transcriptional expression of SEMA3F and NRP2 in a cohort of 53 patients with cN0 squamous cell carcinoma treated with an elective neck dissection. Occult lymph node metastases were found in 37.7% of the patients. Patients with occult lymph node metastases (cN0/pN+) had significantly lower SEMA3F expression values than patients without lymph node involvement (cN0/pN0). Considering the expression of the SEMA3F-NRP2 genes, patients were classified into two groups according to the risk of occult nodal metastasis: Group 1 (n = 34), high SEMA3F/low NRP2 expression, with a low risk of occult nodal involvement (14.7% cN0/pN+); Group 2 (n = 19), low SEMA3F or high SEMA3F/high NRP2 expression, with a high risk of occult nodal involvement (78.9% cN0/pN+). Multivariate analysis showed that patients in Group 2 had a 26.2 higher risk of lymph node involvement than patients in Group 1. There was a significant relationship between the transcriptional expression values of the SEMA3F-NRP2 genes and the risk of occult nodal metastases.

The oncogenic role of LncRNA FAM83C-AS1 in colorectal cancer development by epigenetically inhibits SEMA3F via stabilizing EZH2.

Inactivation of Semaphorin 3F (SEMA3F) is involved in colorectal cancer development. However, the mechanism by which SEMA3F is regulated remains elusive. Deregulation of lncRNAs have been implicated in multiple human malignancies, including colorectal cancer (CRC). To date, it is still unclear whether and how lncRNA regulates SEMA3F expression and mediates CRC progression. Here we identify the oncogenic role of lncRNA FAM83C antisense RNA 1 (FAM83C-AS1) in CRC. FAM83C-AS1 is upregulated in tumor tissues and cells of CRC, which is negatively correlated with SEMA3F expression. Reciprocally, knockdown of FAM83C-AS1 exhibits inhibitory effects on the malignant transformation of CRC. Moreover, our data uncover that FAM83C-AS1 enhances methylation of SEMA3F promoter H3K27me3 via upregulating methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). Specifically, FAM83C-AS1 stabilizes EZH2 protein through recruiting the zinc finger RANBP2-type containing 1 (ZRANB1). Both in vitro and in vivo rescue assays exhibit that SEMA3F is dispensable for the tumor-promoting effects of FAM83C-AS1 on CRC progression. Our data thus demonstrate that the epigenetic role of FAM83C-AS1 in suppression of SEMA3F expression through stabilization of EZH2 to drive CRC progression, which may be conducive to discovering novel therapeutic targets for the treatment of CRC.

Differences in the Expression Pattern of mRNA Protein SEMA3F in Endometrial Cancer in vitro under Cisplatin Treatment.

BackgroundSemaphorin 3F (SEMA3F) plays a substantial role in carcinogenesis, because of its role in inducing angiogenesis, and creating a microenvironment for the developing tumor.ObjectiveThe purpose of this work was to assess the impact of cisplatin, depending on the concentration and exposure time on the expression pattern of SEMA3F in an endometrial cancer cell line.Materials and MethodsCultures of the Ishikawa endometrial cancer cells were incubated with cisplatin with the following concentrations: 2.5µM; 5µM; and 10µM and for the following periods of time: 12; 24; and 48 hours. Cells not incubated with the drug constituted the control in the experiment. To determine the effect of cisplatin on the expression of SEMA3F, the real-time quantitative reverse transcription reaction (RtqPCR; mRNA) was used, as well as the ELISA assay (protein). The statistical analysis was done with the admission of p<0.05.ResultsThe silencing of SEMA3F expression on the transcriptome and proteome levels in a culture unexposed to the effects of cisplatin in comparison to endometrial cancer cells under the influence of cisplatin (p<0.05) were noted. Along with an increase in the concentration of the drug used, the number of copies of the gene transcript, during the shortest incubation period had a gradual increase. Only for the highest concentration of the drug, substantial statistical differences in the expression of the SEMA3F protein between 24 and 48 hour incubation periods (p<0.05) were determined.ConclusionUsing cisplatin in an endometrial cancer cell culture results in an increased expression of SEMA3F, which advantageously affects the normalization of the neoplastic angiogenic process and lowers the proliferation of the cells making up the mass of the tumor.

Semaphorin‐3F, a Potential Biomarker for Lymphatic Anomalies and Bone Cell Function

Lymphatic anomalies (LA) are rare conditions characterized by abnormal vascularization of lymphatic vessels (lymphangiogenesis). Gorham‐Stout Disease (GSD) is an aggressive type of LA which invades cortical bone and makes it “disappear”. There is little evidence elucidating the etiology of GSD and its osteolytic tendencies due to the rarity of the disease. In addition, there are no biomarkers capable of predicting GSD progression or treatment outcome. Normal bone does not have lymphatic vessels. It is believed that in GSD lymphatic endothelial cells (LEC) undergo genetic changes early in development that facilitate their migration and vessel formation in bone. LECs and their secretome content (lymph) are likely both crucial to lymphatic migration into bone and the cortical destruction seen in GSD. In this study, we focused on the LEC secretome with the goal of identifying proteins capable of modifying LEC and bone cell interactions. We initially assessed the effects of normal LEC conditioned media (LEC‐CM) on bone cell differentiation and function in vitro, and found that LEC‐CM stimulates osteoclast differentiation. Next, we subjected LEC‐CM to mass spectrometry and over 500 proteins were identified; we focused specifically on Semaphorin‐3F (SEMA3F) as SEMA3F effectively inhibits lymphangiogenesis in part, by competing with vascular endothelial growth factor‐C (VEGF‐C), for binding to the neuropilin‐2 receptor. We measured mRNA expression of both SEMA3F and VEGF‐C in untreated and Rapamycin treated LECs, a clinically effective therapy for patients with lymphatic anomalies. SEMA3F mRNA expression was upregulated while VEGF‐C was downregulated in Rapamycin treated versus untreated LEC cultures. We next assessed the effects of exogenous SEMA3F on LEC viability and on osteoblast differentiation and function. We found that SEMA3F reduced LEC viability in a dose‐dependent fashion. In addition, SEMA3F inhibited osteoblast differentiation as measured by alkaline‐phosphatase activity and matrix mineralization independent of its effects on osteoblast viability or proliferation. Experiments are currently underway to determine the expression/localization of SEMA3F, VEGF‐C and neuropilin‐2 in lymphatic anomalies (LA) tissues obtained from pediatric patients at our facility. We expect that SEMA3F expression will be downregulated while VEGF‐C will be upregulated in LA compared to normal lymphatics. In summary, our data suggest that SEMA3F might be a possible biomarker for patient with LA conditions or contributes to their pathogenesis.Support or Funding InformationLymphatic Malformation Institute, USA | Rebecca D. Considine Institute of Research, Akron Children’s Hospital, Akron, OH, USA| Integrated Pharmaceutical Medicine Program, NEOMED, Rootstown, OH, USA

Endothelial Semaphorin 3F Maintains Endothelial Barrier Function and Inhibits Monocyte Migration.

In normal physiology, endothelial cells (ECs) form a vital barrier between the blood and underlying tissue controlling leukocyte diapedesis and vascular inflammation. Emerging data suggest that neuronal guidance cues, typically expressed during development, have roles outside the nervous system in vascular biology and immune responses. In particular, Class III semaphorins have been reported to affect EC migration and angiogenesis. While ECs express high levels of semaphorin 3F (SEMA3F), little is known about its function in mature ECs. Here we show that SEMA3F expression is reduced by inflammatory stimuli and increased by laminar flow. Endothelial cells exposed to laminar flow secrete SEMA3F, which subsequently binds to heparan sulfates on the surface of ECs. However, under pro-inflammatory conditions, reduced levels of SEMA3F make ECs more prone to monocyte diapedesis and display impaired barrier function as measured with an electric cell–substrate impedance sensing system and a microfluidic system. In addition, we demonstrate that SEMA3F can directly inhibit the migration of activated monocytes. Taken together, our data suggest an important homeostatic function for EC-expressed SEMA3F, serving as a mediator of endothelial quiescence.

SEMA3F Promotes Liver Hepatocellular Carcinoma Metastasis by Activating Focal Adhesion Pathway.

Previous studies have shown that semaphorin-3F (SEMA3F) functions as a tumor suppressor in several tumor types. However, the role of SEMA3F in the metastasis and prognosis of liver hepatocellular carcinoma (LIHC) remains unknown. In this study, by performing bioinformatics analysis on the transcriptome profiles from The Cancer Genome Atlas (TCGA), we demonstrated that SEMA3F was significantly upregulated in LIHC tissues, compared with normal controls. Moreover, the expression value of SEMA3F was positively correlated with patients' pathological stages and tumor metastasis, predicting a poor overall survival. Besides, SEMA3F expression level was negatively correlated with its methylation level, but positively correlated with its gene copy number. Differential expression analysis of LIHC samples with high or low SEMA3F expression values suggested that 983 genes were differentially expressed, among which 723 genes were upregulated and 260 genes were downregulated. Furthermore, enrichment analysis of differentially expressed genes revealed that SEMA3F was involved in the activation of focal adhesion pathway, which induced tumor metastasis. Taken together, our results suggested that the oncogenic function of SEMA3F promoted hepatocellular carcinoma metastasis by activating focal adhesion pathway.

Semaphorin 3F Serves as a Tumor Suppressor in Esophageal Squamous Cell Carcinoma and is Associated With Lymph Node Metastasis in Disease Progression.

Background:Esophageal squamous cell carcinoma is one of the leading aggressive malignancies with high mortality. Semaphorin 3F has been reported to be involved in lymphangiogenesis by interacting the vascular endothelial growth factor C/neuropilin 2 axis. This study aimed to assess the clinical and functional role of semaphorin 3F and preliminarily evaluate the relationship between semaphorin 3F and lymph node metastasis in esophageal squamous cell carcinoma.Methods:The messenger RNA expression of semaphorin 3F was analyzed using quantitative real-time polymerase chain reaction. The expression differences of semaphorin 3F between patients having esophageal squamous cell carcinoma with and without lymph node metastasis were assessed, and the correlation of semaphorin 3F with vascular endothelial growth factor C and neuropilin 2 was estimated. The prognostic value of semaphorin 3F was evaluated using Kaplan-Meier survival curves and Cox regression analysis. Gain- and loss-functional cell experiments were performed to explore the biological function of semaphorin 3F, vascular endothelial growth factor C, and neuropilin 2.Results:The messenger RNA expression of semaphorin 3F was reduced in esophageal squamous cell carcinoma tissues compared with normal tissues, and lower semaphorin 3F expression was observed in patients having esophageal squamous cell carcinoma with positive lymph node metastasis. Semaphorin 3F expression was associated with lymph node metastasis and negatively correlated with vascular endothelial growth factor C and neuropilin 2. Lower semaphorin 3F expression was related to a poor overall survival of esophageal squamous cell carcinoma and served as an independent prognostic indicator. In esophageal squamous cell carcinoma cells, semaphorin 3F messenger RNA expression was also decreased compared with normal cells, and the overexpression of semaphorin 3F could significantly inhibit cell proliferation, migration, and invasion. The downregulation of vascular endothelial growth factor C and neuropilin 2 could inhibit cell proliferation, migration, and invasion of esophageal squamous cell carcinoma cells.Conclusion:All data indicate that semaphorin 3F serves as a potential prognostic biomarker and tumor suppressor of esophageal squamous cell carcinoma and may be involved in the lymph node metastasis development through regulating neuropilin 2.

Clinical relevance of semaphorin-3F in patients with prostate cancer.

To identify prognosis predictors for patients with prostate cancer (PCa). Four independent PCa microarray datasets (GSE32448, GSE16560, GSE79957 and GSE17951) were reanalyzed to characterize the expression of semaphorin-3F (SEMA3F) gene between PCa patients and normal prostate tissues and the correlation between SEMA3F expression and the age, tumor/nodes/metastasis (TNM) staging, Gleason Grade Group, prostate-specific antigen level and overall survival of PCa patients. Gene set enrichment analysis was applied to investigate the potential relevant mechanisms regarding the expression of SEMA3F and the proliferation of PCa cells. The level of SEMA3F was significantly higher in normal prostate tissues compared with that in PCa cells (P.

Chemorepulsion as a novel therapeutic concept to inhibit pancreatic cancer metastasis

Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate primarily due to the absence of effective pharmacologic treatments and the limited effects of surgical resection in the early stages of the disease. The most frequent cause of death from the disease is due to its tendency to metastasize to the liver, at which point the chances of long‐term survival drop significantly. Therefore, there is an urgent need to find a drug therapy that not only affects the primary tumor, but perhaps more importantly, prevents the formation of metastases in the liver. Neuropilin 2 (Nrp2) is a transmembrane co‐receptor protein that binds a secreted protein called semaphorin 3F (S3F). Nrp2 is not expressed in the liver but is highly overexpressed in PDAC cells and PDAC‐associated endothelial cells. Based on these observations, we hypothesized that S3F expression in the liver could repel metastasizing PDAC cells. As part of a series of prevention trials, we performed an IV injection of S3F expressing adenovirus in mice and thereby induced the expression of the protein in the liver. Three days later we performed an orthotopic injection of syngeneic PDAC cells. For our intervention trials, we inverted the sequence of tumor and virus injections. Our results showed a significant reduction in tumor metastases in the experimental SEMA3F‐treated group compared to control virus treated mice. But the actions of Nrp2 are not limited to its ability to mediate repulsion. The tumor microvessel density and hence the overall PDAC tumor size was also reduced, thereby illustrating the systemic anti‐angiogenic effects of S3F‐mediated signaling via Nrp2. The action of Nrp2 on tumor growth was further elucidated by repeating the same experimental procedure in Nrp2‐deficient mice. Again, we saw a reduction in size and microvessel density within the primary tumor, which validates our initial hypothesis that Nrp2 is necessary for tumor growth and angiogenesis in PDAC. In summary the therapeutic effects of inhibiting Nrp2 are twofold: First and foremost, we have shown that S3F expression in the liver will repel Nrp2‐positive PDAC cells, as well as reduce tumor growth in the pancreas compared to the control. Finally, we have also demonstrated the anti‐angiogenic effects of S3F.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Semaphorin 3F expression is reduced in pregnancy complicated by preeclampsia. An observational clinical study.

Background and objectivePreeclampsia is a systemic disorder, affecting 2–10% of pregnancies, characterized by a deregulated pro- and anti-angiogenic balance. Semaphorin 3F is an angiogenesis inhibitor. We aimed to investigate whether semaphorin 3F expression is modulated in preeclampsia.Design, setting, participants, and measurementsWe performed two observational single center cohort studies between March 2013 and August 2014. In the first we enrolled 110 consecutive women, undergoing an elective cesarean section; in the second we included 150 consecutive women undergoing amniocentesis for routine clinical indications at 16–18 week of gestation. Semaphorin 3F concentration was evaluated in maternal peripheral blood, venous umbilical blood and amniotic fluid, along with its placenta protein expression at the time of delivery in the first study group and in the amniotic fluid at 16–18 weeks of gestation in the second study group.ResultsIn the first study 19 patients presented at delivery with preeclampsia. Semaphorin 3F placenta tissue expression was significantly reduced in preeclampsia. In addition, semaphorin 3F level at delivery was significantly lower in serum, amniotic fluid and venous umbilical blood of preeclamptic patients compared with normal pregnant women. In the prospective cohort study 14 women developed preeclampsia. In this setting, semaphorin 3F amniotic level at 16–18 weeks of gestation was reduced in women who subsequently developed preeclampsia compared to women with a normal pregnancy. ROC curve analysis showed that semaphorin 3F amniotic levels could identify women at higher risk of preeclampsia.ConclusionsSemaphorin 3F might represent a predictive biomarker of preeclampsia.

Association between mossy fiber sprouting and expression of semaphorin-3f protein in dentate gyrus of hippocampus in lithium-pilocarpine-induced status epilepticus mouse model

Objectives: Mossy fiber sprouting is involved in the pathogenesis of mesial temporal lobe epilepsy. But the exact mechanism of formation of mossy fiber sprouting is still unclear. Semaphorin-3f protein could inhibit the growth of neuron axons. The aim of this research is to evaluate the association between semaphorin-3f expression and mossy fiber sprouting.Methods: We established pilocarpine-induced status epilepticus (PISE) models firstly. Then, mossy fiber sprouting in the hippocampus of PISE models was examined by Timm staining. Expression of semaphorin-3f was evaluated by western blot analysis and immunohistochemical examination. Expression of semaphorin-3f protein in different subregions of hippocampus and its relationship with mossy fiber sprouting were studied.Results: We found that in PISE group, mossy fiber sprouting appeared in dentate gyrus (DG) region. It started to develop in the latent phase of PISE group and increased significantly in the chronic phase. Expression of semaphorin-3f protein in DG region started to decrease in the latent phase, and stayed at low level in the chronic phase. No such change was found in the other groups.Conclusions: These results indicate that the decrease in semaphorin-3f expression in DG region was in parallel to the change of mossy fiber sprouting in PISE models, suggesting that mossy fiber sprouting is closely associated with reduced expression of semaphorin-3f in this model.

The axon guidance molecule semaphorin 3F is a negative regulator of tumor progression and proliferation in ileal neuroendocrine tumors.

Gastro-intestinal neuroendocrine tumors (GI-NETs) are rare neoplasms, frequently metastatic, raising difficult clinical and therapeutic challenges due to a poor knowledge of their biology. As neuroendocrine cells express both epithelial and neural cell markers, we studied the possible involvement in GI-NETs of axon guidance molecules, which have been shown to decrease tumor cell proliferation and metastatic dissemination in several tumor types. We focused on the role of Semaphorin 3F (SEMA3F) in ileal NETs, one of the most frequent subtypes of GI-NETs.SEMA3F expression was detected in normal neuroendocrine cells but was lost in most of human primary tumors and all their metastases. SEMA3F loss of expression was associated with promoter gene methylation. After increasing endogenous SEMA3F levels through stable transfection, enteroendocrine cell lines STC-1 and GluTag showed a reduced proliferation rate in vitro. In two different xenograft mouse models, SEMA3F-overexpressing cells exhibited a reduced ability to form tumors and a hampered liver dissemination potential in vivo. This resulted, at least in part, from the inhibition of mTOR and MAPK signaling pathways.This study demonstrates an anti-tumoral role of SEMA3F in ileal NETs. We thus suggest that SEMA3F and/or its cellular signaling pathway could represent a target for ileal NET therapy.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Semaphorin 3F forms an anti-angiogenic barrier in outer retina

Semaphorins are known modulators of axonal sprouting and angiogenesis. In the retina, we identified a distinct and almost exclusive expression of Semaphorin 3F in the outer layers. Interestingly, these outer retinal layers are physiologically avascular. Using functional in vitro models, we report potent anti-angiogenic effects of Semaphorin 3F on both retinal and choroidal vessels. In addition, human retinal pigment epithelium isolates from patients with pathologic neovascularization of the outer retina displayed reduced Semaphorin 3F expression in 10 out of 15 patients. Combined, these results elucidate a functional role for Semaphorin 3F in the outer retina where it acts as a vasorepulsive cue to maintain physiologic avascularity.

RORα Suppresses Breast Tumor Invasion by Inducing SEMA3F Expression

Inactivation of tumor suppressors and inhibitory microenvironmental factors is necessary for breast cancer invasion; therefore, identifying those suppressors and factors is crucial not only to advancing our knowledge of breast cancer, but also to discovering potential therapeutic targets. By analyzing gene expression profiles of polarized and disorganized human mammary epithelial cells in a physiologically relevant three-dimensional (3D) culture system, we identified retinoid orphan nuclear receptor alpha (RORα) as a transcription regulator of semaphorin 3F (SEMA3F), a suppressive microenvironmental factor. We showed that expression of RORα was downregulated in human breast cancer tissue and cell lines, and that reduced mRNA levels of RORα and SEMA3F correlated with poor prognosis. Restoring RORα expression reprogrammed breast cancer cells to form noninvasiveness structures in 3D culture and inhibited tumor growth in nude mice, accompanied by enhanced SEMA3F expression. Inactivation of RORα in nonmalignant human mammary epithelial cells inhibited SEMA3F transcription and impaired polarized acinar morphogenesis. Using chromatin immunoprecipitation and luciferase reporter assays, we showed that transcription of SEMA3F is directly regulated by RORα. Knockdown of SEMA3F in RORα-expressing cancer cells rescued the aggressive 3D phenotypes and tumor invasion. These findings indicate that RORα is a potential tumor suppressor and inhibits tumor invasion by inducing suppressive cell microenvironment.

Semaphorin 3F expression pattern coincides with the sympathetic nerve degeneration induced by oestrogen in the rat uterus

Semaphorin 3F expression pattern coincides with the sympathetic nerve degeneration induced by oestrogen in the rat uterus

Expression and prognostic value of SEMA3F protein in hepatocelluar carcinoma

Objective To investigate the expression of Semaphorin 3F (SEMA3F) protein in hepatocellular carcinoma (HCC) and to demonstrate its relationship with clinicopathological features and prognosis of HCC. Methods Western Blotting was carried out in 32 hepatocellular carcinoma samples and matched perineoplastic tissues to detect the expression of SEMA3F protein. The relationship between SEMA3F protein expression and clinicopathological features as well as prognosis of HCC patients was analyzed. Immunohistochemistry was used to show the location of SEMA3F in HCC cells and its relationship with microvessel density (MVD). Results The expression of SEMA3F protein in HCC tissues was significantly higher than in the perineoplastic tissues (447.78± 48.26 vs 618.93 ±61.23, P＜0. 05) and it was correlated closely with tumor capsulation and tumor nodular number (P＜0.05). Based on the Western Blotting and clinical follow-up data, we found that the survival time of HCC patients with a higher SEMA3F expression level was longer than those with a lower level, and the recurrent/metastatic time of HCC patients was significantly different between these two groups (P＜0.01). Immunohistochemistry demonstrated that SEMA3F protein localized in the cytoplasm of HCC cells and its expression correlated with HCC MVD. MVD in the low-level group was higher than the high-level group (115.6±30.38 vs 86. 56±17.94, P＜0.01). Conclusions SEMA3F expression in HCC was significantly down-regulated and correlated closely with tumor-capsulation, nodular number, and MVD, implicating SEMA3F may play an important role in recurrence and metastasis of HCC. It can be regarded as a prognostic marker in HCC patients. Key words: Hepatocellular carcinoma; Semaphorin 3F; Recurrence/metastasis; Prognosis

Id2 Promotes Tumor Cell Migration and Invasion through Transcriptional Repression of Semaphorin 3F

Id proteins (Id1 to Id4) are helix-loop-helix transcription factors that promote metastasis. It was found that Semaphorin 3F (SEMA3F), a potent inhibitor of metastasis, was repressed by Id2. High metastatic human tumor cell lines had relatively high amounts of Id2 and low SEMA3F levels compared with their low metastatic counterparts. No correlation between metastatic potential and expression of the other Id family members was observed. Furthermore, ectopic expression of Id2 in low metastatic tumor cells downregulated SEMA3F and, as a consequence, enhanced their ability to migrate and invade, two requisite steps of metastasis in vivo. Id2 overexpression was driven by the c-myc oncoprotein. SEMA3F was a direct target gene of the E47/Id2 pathway. Two E-box sites, which bind E protein transcription factors including E47, were identified in the promoter region of the SEMA3F gene. E47 directly activated SEMA3F promoter activity and expression and promoted SEMA3F biological activities, including filamentous actin depolymerization, inactivation of RhoA, and inhibition of cell migration. Silencing of SEMA3F inhibited the E47-induced SEMA3F expression and biological activities, confirming that these E47-induced effects were SEMA3F dependent. E47 did not induce expression of the other members of the SEMA3 family. Id2, a dominant-negative inhibitor of E proteins, abrogated the E47-induced SEMA3F expression and biological activities. Thus, high metastatic tumor cells overexpress c-myc, leading to upregulation of Id2 expression; the aberrantly elevated amount of Id2 represses SEMA3F expression and, as a consequence, enhances the ability of tumor cells to migrate and invade.