Reduced expression of semaphorin 4D and plexin-B in breast cancer is associated with poorer prognosis and the potential linkage with oestrogen receptor

Role of semaphorins, neuropilins and plexins in cancer progression

Progress in understanding nervous system-cancer interconnections has emphasized the functional role of semaphorins (SEMAs) and their receptors, neuropilins (NRPs) and plexins (PLXNs), in cancer progression. SEMAs are a conserved and extensive family of broadly expressed soluble and membrane-associated proteins that were first described as regulators of axon guidance and neural and vascular development. However, recent advances have shown that they can have a dual role in cancer progression, acting either as tumor promoters or suppressors. SEMAs effects result from their interaction with specific co-receptors/receptors NRPs/PLXNs, that have also been described to play a role in cancer progression. They can influence both cancer cells and tumor microenvironment components modulating various aspects of tumorigenesis such as oncogenesis, tumor growth, invasion and metastatic spread or treatment resistance. In this review we focus on the role of these axon guidance signals and their receptors and co-receptors in various aspects of cancer. Furthermore, we also highlight their potential application as novel approaches for cancer treatment in the future.

Emerging roles and mechanisms of semaphorins activity in cancer

Semaphorins are regulatory molecules that are linked to the modulation of several cancer processes, such as angiogenesis, cancer cell invasiveness and metastasis, tumor growth, as well as cancer cell survival. Semaphorin (SEMA) activity depends on the cancer histotypes and their particularities. In broad terms, the effects of SEMAs result from their interaction with specific receptors/co-receptors - Plexins, Neuropilins and Integrins - and the subsequent effects upon the downstream effectors (e.g. PI3K/AKT, MAPK/ERK). The present article serves as an integrative review work, discussing the broad implications of semaphorins in cancer, focusing on cell proliferation/survival, angiogenesis, invasion, metastasis, stemness, and chemo-resistance/response whilst highlighting their heterogeneity as a family. Herein, we emphasized that semaphorins are largely implicated in cancer progression, interacting with the tumor microenvironment components. Whilst some SEMAs (e.g. SEMA3A, SEMA3B) function widely as tumor suppressors, others (e.g. SEMA3C) act as pro-tumor semaphorins. The differences observed in terms of the biological structure of SEMAs and the particularities of each cancer histotypes require that each semaphorin be viewed as a unique entity, and its roles must be researched accordingly. A more in-depth and comprehensive view of the molecular mechanisms that promote and sustain the malignant behavior of cancer cells is of utmost importance.

Plexin-B3 expression stimulates MET signaling, breast cancer stem cell specification, and lung metastasis

Intratumoral hypoxia is a microenvironmental feature that promotes breast cancer progression and is associated with cancer mortality. Plexin B3 (PLXNB3) is highly expressed in estrogen receptor-negative breast cancer, but the underlying mechanisms and consequences have not been thoroughly investigated. Here, we report that PLXNB3 expression is increased in response to hypoxia and that PLXNB3 is a direct target gene of hypoxia-inducible factor 1 (HIF-1) in human breast cancer cells. PLXNB3 expression is correlated with HIF-1α immunohistochemistry, breast cancer grade and stage, and patient mortality. Mechanistically, PLXNB3 is required for hypoxia-induced MET/SRC/focal adhesion kinase (FAK) and MET/SRC/STAT3/NANOG signaling as well as hypoxia-induced breast cancer cell migration, invasion, and cancer stem cell specification. PLXNB3 knockdown impairs tumor formation and lung metastasis in orthotopic breast cancer mouse models.

Crosstalk between the peripheral nervous system and breast cancer influences tumor progression

Recent studies have shown that peripheral nerves play an important role in the progression of breast cancer. Breast cancer cells (BCCs) promote local peripheral nerve growth and branching by secreting neuroactive molecules, including neurotrophins and axon guidance molecules (AGMs). Sympathetic nerves promote breast cancer progression, while parasympathetic and sensory nerves mainly have anti-tumor effects in the progression of breast cancer. Specifically, peripheral nerves can influence the progression of breast cancer by secreting neurotransmitters not only directly binding to the corresponding receptors of BCCs, but also indirectly acting on immune cells to modulate anti-tumor immunity. In this review, we summarize the crosstalk between breast cancer and peripheral nerves and the roles of important neuroactive molecules in the progression of breast cancer. In addition, we summarize indicators, including nerve fiber density and perineural invasion (PNI), that may help determine the prognosis of breast cancer based on current research results, as well as potential therapeutic approaches, such as β-blockers and retroviral-mediated genetic neuroengineering techniques, that may enhance the prognosis of breast cancer. In addition, we propose suggestions for future research priorities based on a current lack of knowledge in this area.

Class IV semaphorins in disease pathogenesis

Semaphorins are a large family of secreted and/or transmembrane proteins, originally identified as proteins that function in axon guidance during neuronal development. However, semaphorins play crucial roles in other physiological and pathological processes, including immune responses, angiogenesis, maintenance of tissue homeostasis, and cancer progression. Class IV semaphorins may be present as transmembrane and soluble forms and are implicated in the pathogenesis of various diseases. This review discusses recent progress on the roles of class IV semaphorins determined by clinical and experimental pathology studies.

Glycoproteomics Identifies Plexin-B3 as a Targetable Cell Surface Protein Required for the Growth and Invasion of Triple-Negative Breast Cancer Cells

Driven by the lack of targeted therapies, triple-negative breast cancers (TNBCs) have the worst overall survival of all breast cancer subtypes. Considering that cell surface proteins are favorable drug targets and are predominantly glycosylated, glycoproteome profiling has significant potential to facilitate the identification of much-needed drug targets for TNBCs. Here, we performed N-glycoproteomics on six TNBCs and five normal control (NC) cell lines using hydrazide-based enrichment. Quantitative proteomics and integrative data mining led to the discovery of Plexin-B3 (PLXNB3), a previously undescribed TNBC-enriched cell surface protein. Furthermore, siRNA knockdown and CRISPR-Cas9 editing of in vitro and in vivo models show that PLXNB3 is required for TNBC cell line growth, invasion, and migration. Altogether, we provide insights into N-glycoproteome remodeling associated with TNBCs and functional evaluation of an extracted target, which indicate the surface protein PLXNB3 as a potential therapeutic target for TNBCs.

Circular RNA Circ_0013958 Functions as a Tumor Promoter in Ovarian Cancer by Regulating miR-637/PLXNB2 Axis

Background: Circular RNAs (circRNAs) have emerged as important regulators in diverse human malignancies, including ovarian cancer (OC). This study was performed to explore the function and regulatory mechanism underlying circ_0013958 in OC progression. Methods: Quantitative real-time polymerase chain reaction (qRT-PCR) or Western blot assay was applied to examine the expression of circ_0013958, microRNA-637 (miR-637), and Plexin B2 (PLXNB2). The target relationship between miR-637 and circ_0013958 or PLXNB2 was verified by dual-luciferase reporter assay or RNA immunoprecipitation (RIP) assay. Cell Counting Kit-8 (CCK-8) and colony formation assays were employed to detect cell viability and clonogenicity ability, respectively. Cell migration and invasion were analyzed by Transwell assay. Cell apoptosis was monitored by flow cytometry. The role of circ_0013958 in vivo was determined by xenograft tumor assay. Results: Circ_0013958 and PLXNB2 were upregulated, while miR-637 was downregulated in OC tissues and cells. Circ_0013958 acted as a sponge for miR-637 to regulate the expression of PLXNB2 in OC cells. The repression effects of circ_0013958 knockdown on cell proliferation, migration, invasion, and apoptosis in OC cells were partly attenuated by the miR-637 inhibitor. And miR-637 targeted PLXNB2 to suppress OC cell proliferation, migration, and invasion. Moreover, circ_0013958 silencing blocked OC tumor growth in vivo. Conclusion: Circ_0013958 knockdown impeded OC development through modulating the miR-637/PLXNB2 axis, highlighting a therapeutic target for OC.

SEMA4D Knockdown Attenuates β-Catenin-Dependent Tumor Progression in Colorectal Cancer

Semaphorin 4D (SEMA4D), a protein originally demonstrated to regulate the immune system and axonal growth cone collapse in the developing central nervous system, is overexpressed in various human malignancies, including colorectal cancer (CRC). This investigation was undertaken to examine the effects of SEMA4D silencing on the biological properties of the CRC cell line. SW48 cells were transfected with a siRNA-targeting SEMA4D. The mRNA expression of underlying pro- and antiapoptotic proteins including Bax, Bcl-2, P53, and caspase-3, cancer stem cell (CSC) markers, epithelial-mesenchymal transition (EMT) markers, MMP-2, and MMP-9 was examined using qRT-PCR. Further, the protein expression of E-cadherin and β-catenin was confirmed by Western blot. SW48 cell migration and MMP activity were detected using scratch and zymography analysis, respectively. Finally, the apoptosis rate was assessed via the flowcytometry test. SEMA4D knock-down was associated with a considerable suppression of in vitro cell viability, EMT-related genes, CSC markers, β-catenin signaling pathway, sphere-forming, cell migration, and MMP-2 activity as well as induction of apoptosis. This study identifies the inhibitory effects of SEMA4D gene silencing on tumor progression. Thereby, this might conclude a possible alternative to cancer therapy by targeting several prominent pathways involved in cancer through SEMA4D suppression.

IP6K2 predicts favorable clinical outcome of primary breast cancer

The inositol hexakisphosphate kinase (IP6K) 1 and 2 genes are localized at 3p21.31, a highly altered gene-dense chromosomal region in cancer. The IP6Ks convert IP6 to IP7, which inhibits activation of the tumor-promoting PI3K/Akt/mTOR signaling pathway. IP6K2 has been suggested to be involved in p53-induced apoptosis, while IP6K1 may stimulate tumor growth and migration. The present study aimed to elucidate the role of the two IP6Ks in predicting outcome in patients with breast cancer. To the best of our knowledge, the role of IP6K was analyzed for the first time in tumors from three cohorts of patients with breast cancer; one Swedish low-risk cohort, one Dutch cohort and the TCGA dataset. Analyses of gene -and protein expression and subcellular localization were included. IP6K2 gene expression was associated with ER positivity and nuclear p-Akt. Improved prognosis was detected with high IP6K2 gene expression compared with low IP6K2 gene expression in systemically untreated patients in the Swedish low-risk and Dutch cohorts. In the TCGA dataset, IP6K2 prognostic value was significant when selecting for tumors with wild-type TP53. A multivariable analysis testing IP6K2 against other cancer-related genes at 3p.21.31, including IP6K1 and clinical biomarkers, revealed that IP6K2 was associated with decreased risk of distant recurrence. IP6K1 was associated with increased risk of distant recurrence in the multivariable test and protein analysis revealed trends of worse prognosis with high IP6K1 in the cytoplasm. The expression levels of IP6K1 and IP6K2 were associated to a high extent; however, a diverging prognostic value of the two genes was observed in breast cancer. The present data suggest that IP6K2 can be a favorable prognostic factor, while IP6K1 may not be.

Semaphorins as emerging clinical biomarkers and therapeutic targets in cancer

Semaphorins are a large family of developmental regulatory signals, characterized by aberrant expression in human cancers. These molecules crucially control cell-cell communication, cell migration, invasion and metastasis, tumor angiogenesis, inflammatory and anti-cancer immune responses. Semaphorins comprise secreted and cell surface-exposed molecules and their receptors are mainly found in the Plexin and Neuropilin families, which are further implicated in a signaling network controlling the tumor microenvironment. Accumulating evidence indicates that semaphorins may be considered as novel clinical biomarkers for cancer, especially for the prediction of patient survival and responsiveness to therapy. Moreover, preclinical experimental studies have demonstrated that targeting semaphorin signaling can interfere with tumor growth and/or metastatic dissemination, suggesting their relevance as novel therapeutic targets in cancer; this has also prompted the development of semaphorin-interfering molecules for application in the clinic. Here we will survey, in diverse human cancers, the current knowledge about the relevance of semaphorin family members, and conceptualize potential lines of future research development in this field.

Inhibition of semaphorin 4D enhances chemosensitivity by increasing 5-fluorouracile-induced apoptosis in colorectal cancer cells

Overexpression of semaphorin 4D (SEMA4D), an immune semaphorin, is found in various human malignancies, including colorectal cancer (CRC). In this study, we explored the relationship between silencing SEMA4D expression and 5-fluorouracil (5-FU) response in the colorectal cancer cell line. SW48 cells were transfected with a short interfering RNA (siRNA) in order to silence SEMA4D gene expression and then exposed to 5-FU for 48 h. The down-regulation of SEMA4D expression was confirmed by qRT-PCR and the particular concentration of 5-FU was acquired using MTT assay. Flow cytometry and western blot were used to evaluate apoptosis rate and pro- and anti-apoptotic expression levels of proteins involved in apoptosis including Bax, Bcl-2, P53, and caspase-3. Other oncogenic activities including epithelial-mesenchymal transition (EMT) process, cancer stem cell (CSC) markers, and β-catenin pathway were investigated using qRT-PCR, and western blot. The proliferation was analyzed via colony formation test and cell invasion was assessed by transwell assay. Our data demonstrate that SEMA4D silencing results in strikingly elevated apoptosis in response to 5-FU treatment and leads to down-regulation of Bcl-2 and overexpression of Bax, P53, and caspase-3 in protein levels. Furthermore, the mRNA and protein expression levels of β-catenin, as well as transcript expressions of CSCs and EMT markers, were remarkably diminished. However, mRNA expression of E-cadherin as an epithelial marker was significantly increased in 5-FU treatment combined with siRNA SEMA4D. This study implicates that the silencing of SEMA4D by siRNA promotes the chemosensitivity of SW48 cells to 5-FU and it may be a potential therapeutic agent for colon cancer therapy.

Insufficient CD100 shedding contributes to suppression of CD8+ T-cell activity in non-small cell lung cancer

CD100 is an immune semaphorin constitutively expressed on T-cells. Matrix metalloproteinase (MMP) is an important mediator of membrane-bound CD100 (mCD100) cleavage to generate soluble CD100 (sCD100), which has immunoregulatory activity in immune cell responses. The aim of the study was to investigate the level and role of sCD100 and mCD100 in modulating CD8⁺ T-cell function in non-small cell lung cancer (NSCLC). sCD100 and MMP-14 levels in the serum and bronchoalveolar lavage fluid (BALF), and mCD100 expression on peripheral and lung-resident CD8⁺ T-cells were analysed in NSCLC patients. The ability to induce sCD100 and the effect of MMP-14 on mCD100 shedding for the regulation of non-cytolytic and cytolytic functions of CD8⁺ T-cells were also analysed in direct and indirect contact co-culture systems. NSCLC patients had lower serum sCD100 and higher mCD100 levels on CD8⁺ T-cells compared with healthy controls. BALF from the tumour site also had decreased sCD100 and increased mCD100 on CD8⁺ T-cells compared with the non-tumour site. Recombinant CD100 stimulation enhanced non-cytolytic and cytolytic functions of CD8⁺ T-cells from NSCLC patients, whereas blockade of CD100 receptor CD72 attenuated CD8⁺ T-cell activity. NSCLC patients had lower MMP-14 in the serum and in BALF from the tumour site. Recombinant MMP-14 mediated mCD100 shedding from CD8⁺ T-cell membrane, and led to promotion of CD8⁺ T-cell response in NSCLC patients. Overall, decreased MMP-14 resulted in insufficient CD100 shedding, leading to suppression of peripheral and lung-resident CD8⁺ T-cell activity in NSCLC.

Long noncoding RNA ZEB2-AS1 facilitates laryngeal squamous cell carcinoma progression by miR-6840-3p/PLXNB1 axis

Purpose

To investigate the role of zinc finger E‑box‑binding homeobox 2 antisense RNA 1 (ZEB2-AS1) in regulating laryngeal squamous cell carcinoma (LSCC) progression.

Patients and methods

In this retrospective study, we included all patients who underwent a surgical operation at The First Hospital of Qiqihaer City for LSCC. Then, we compared the expression of ZEB2-AS1 in LSCC tissues and paired healthy tissues. Besides, we also performed a series of functional assays, CCK8 assays, colony formation assays, and transwell assays to examine the functions of LSCC cells after knockdown of ZEB2-AS1. Through bioinformatics analysis, we predicted that ZEB2-AS1 binds to miR-6840-3p and targets PLXNB1.

Results

We indicated that the expression of ZEB2-AS1 was higher in LSCC tissues compared to the paired adjacent tissues, and ZEB2-AS1 was also highly expressed in LSCC cell lines. Furthermore, we discovered that ZEB2-AS1 promoted cell proliferation, migration and invasion and was associated with poor prognosis. To find the mechanism, we performed bioinformatics analysis. We identified that ZEB2-AS1 binds to miR-6840-3p and targets PLXNB1. Additionally, miR-6840-3p overexpression or knockdown of PLXNB1 decreased the abilities of cell migration and invasion.

Conclusion

These findings demonstrated that overexpression of ZEB2-AS1 promotes LSCC progression. Overexpression of miR-6840-3p or downregulation of PLXNB1 can abrogate ZEB2-AS1-mediated LSCC malignant development.

PLEXIN-B2 promotes the osteogenic differentiation of human bone marrow mesenchymal stem cells via activation of the RhoA signaling pathway

Plexin-B2 (PLXNB2), a transmembrane protein is found in various tissues. Recent studies have indicated the presence of PLXNB2 in large quantity in the growth plates of Sprague-Dawley rats and are believed to be potentially involved in their skeletal development. This study endeavored to analyze the effect of PLXNB2 on the osteogenic differentiation of BMSCs by using gene overexpression and knockdown assays. The results of our study revealed that PLXNB2 was upregulated during BMSCs differentiation into an osteoblastic lineage. By determining the expression levels of specific markers and mineral deposition, the study established that PLXNB2 promotes the osteogenic differentiation of human BMSCs through the activation of the RhoA signaling pathway. In conclusion, the study identified PLXNB2 as a novel regulator that enhanced the osteogenic differentiation of human BMSCs. The enhancing effect of PLXNB2 on osteogenesis of human BMSCs was mediated through activation of RhoA signaling. The results of our study imply that pharmacological targeting of PLXNB2 may initiate a possible improvement in bone formation.

Plasma levels of Semaphorin 4D are decreased by adjuvant tamoxifen but not aromatase inhibitor therapy in breast cancer patients

Background

Semaphorin 4D (Sema4D) is a glycoprotein that inhibits bone formation and has been associated with cancer progression and the occurrence of bone metastases. Recently, Sema4D expression has been linked to estrogen signaling in breast cancer. Endocrine therapies like tamoxifen and aromatase inhibitors (AI) are a standard therapeutic approach in hormone receptor positive breast cancers. Tamoxifen exerts ER-agonistic effects on bone, whereas AI negatively affect bone health by increasing resorption and fracture risk. The effect of endocrine therapies on circulating Sema4D levels in breast cancer patients has not been investigated yet.

Methods

We measured circulating Sema4D plasma levels at primary diagnosis and in a follow-up sample 12 months after surgery in a cohort of 46 pre- and postmenopausal women with primary estrogen receptor positive breast cancer receiving adjuvant tamoxifen or AI.

Results

The mean baseline levels ± SD for Sema4D were 441.6 ± 143.4 pmol/l. No significant differences in total plasma Sema4D were observed when stratifying the patients according to age, menopausal status, tumor subtype, nodal and hormone receptor status, or tumor size. However, Sema4D levels were significantly reduced by 28% (p<0.001) in tamoxifen treated patients 12 months after surgery, whereas no alteration was observed in patients treated with AI.

Conclusion

This finding potentially represents an additional mechanism of the bone-protective properties of tamoxifen and further emphasizes a link between Sema4D and estrogen receptor signaling.

Association between prognosis and SEMA4D/Plexin-B1 expression in various malignancies: A meta-analysis

INTRODUCTION

SEMA4D and its high affinity receptor Plexin-B1 showed a promising prognosis prediction for carcinoma patients in recent studies, we performed a meta-analysis to evaluate the prognostic role of them in various malignancies.

METHODS

A systematic literature search was performed in PubMed, Embase, Web of Science, and CNKI from inception till July 2017. Eligible studies were identified by different reviewers. Hazard ratios (HRs)/related ratios (RRs) and their corresponding 95% confidence intervals (CIs) were extracted to investigate the relevance between malignancies prognosis and SEMA4D/Plexin-B1.

RESULTS

Around 2638 patients from 14 studies were included in this meta-analysis. High expression of SEMA4D was significantly associated with overall survival (OS) and disease-free survival/progression-free survival/recurrence-free survival (DFS/PFS/RFS) in tumors (respectively, HRos = 2.05, 95%CI: 1.68-2.50, P < .001; HRdfs/pfs/rfs = 1.59, 95%CI = 1.27-1.98, P < .001). However, the relationship between SEMA4D expression and prognosis of breast cancer patients was failed to find (HR = 0.76, 95%CI = 0.32-1.82, P = .539). Plexin-B1 level showed a significant positive correlation both with OS and DFS of Caucasian breast cancer patients (respectively, HRos = 0.56, 95%CI: 0.39-0.79, P = .001; HRdfs = 0.68, 95%CI = 0.51-0.90, P = .008) CONCLUSIONS:: SEMA4D could be a prospective biomarker for prognostic prediction of various malignancies except breast cancer. For Caucasian breast cancer patients, SEMA4D's high affinity receptor Plexin-B1 showed a significant positive correlation with survival.

Impact of semaphorin expression on prognostic characteristics in breast cancer

Breast cancer is one of the major causes of cancer-related deaths among women worldwide. Aberrant regulation of various growth factors, cytokines, and other proteins and their receptors in cancer cells drives the activation of various oncogenic signaling pathways that lead to cancer progression. Semaphorins are a class of proteins which are differentially expressed in various types of cancer including breast cancer. Earlier, these proteins were known to have a major function in the nerve cell adhesion, migration, and development of the central nervous system. However, their role in the regulation of several aspects of tumor progression has eventually emerged. There are over 30 genes encoding the semaphorins, which are divided into eight subclasses. It has been reported that some members of semaphorin classes are antiangiogenic and antimetastatic in nature, whereas others act as proangiogenic and prometastatic genes. Because of their differential expression and role in angiogenesis and metastasis, semaphorins emerged as one of the important prognostic factors for appraising breast cancer progression.

Neuroimmune semaphorins as costimulatory molecules and beyond

Several neuronal guidance proteins, known as semaphorin molecules, function in the immune system. This dual tissue performance has led to them being defined as "neuroimmune semaphorins". They have been shown to regulate T cell activation by serving as costimulatory molecules. Similar to classical costimulatory molecules, neuroimmune semaphorins are either constitutively or inducibly expressed on immune cells. In contrast to the classical costimulatory molecule function, the action of neuroimmune semaphorins requires the presence of two signals, the first one provided by TCR/MHC engagement, and the second one provided by B7/CD28 interaction. Thus, neuroimmune semaphorins serve as a "signal three" for immune cell activation and regulate the overall intensity of immune response. The current knowledge on their structures, multiple receptors, specific cell/tissue/organ expression, and distinct functions in different diseases are summarized and discussed in this review.

The Role of Semaphorin 4D in Bone Remodeling and Cancer Metastasis

Semaphorin 4D (Sema4D; CD100) is a transmembrane homodimer 150-kDa glycoprotein member of the Semaphorin family. Semaphorins were first identified as chemorepellants that guide neural axon growth. Sema4D also possesses immune regulatory activity. Recent data suggest other Sema4D functions: inactivation of platelets, stimulation of angiogenesis, and regulation of bone formation. Sema4D is a coupling factor expressed on osteoclasts that inhibits osteoblast differentiation. Blocking Sema4D may, therefore, be anabolic for bone. Sema4D and its receptor Plexin-B1 are commonly dysregulated in cancers, suggesting roles in cancer progression, invasion, tumor angiogenesis, and skeletal metastasis. This review focuses on Sema4D in bone and cancer biology and the molecular pathways involved, particularly Sema4D-Plexin-B1 signaling crosstalk between cancer cells and the bone marrow microenvironment-pertinent areas since a humanized Sema4D-neutralizing antibody is now in early phase clinical trials in cancers and neurological disorders.

Rnd3-induced cell rounding requires interaction with Plexin-B2

Rnd proteins are atypical members of the Rho GTPase family that induce actin cytoskeletal reorganization and cell rounding. Rnd proteins have been reported to bind to the intracellular domain of several plexin receptors, but whether plexins contribute to the Rnd-induced rounding response is not known. Here we show that Rnd3 interacts preferentially with plexin-B2 of the three plexin-B proteins, whereas Rnd2 interacts with all three B-type plexins, and Rnd1 shows only very weak interaction with plexin-B proteins in immunoprecipitations. Plexin-B1 has been reported to act as a GAP for R-Ras and/or Rap1 proteins. We show that all three plexin-B proteins interact with R-Ras and Rap1, but Rnd proteins do not alter this interaction or R-Ras or Rap1 activity. We demonstrate that plexin-B2 promotes Rnd3-induced cell rounding and loss of stress fibres, and enhances the inhibition of HeLa cell invasion by Rnd3. We identify the amino acids in Rnd3 that are required for plexin-B2 interaction, and show that mutation of these amino acids prevents Rnd3-induced morphological changes. These results indicate that plexin-B2 is a downstream target for Rnd3, which contributes to its cellular function.

The combined expression of Semaphorin4D and PlexinB1 predicts disease recurrence in colorectal cancer

Background

Binding to Sema4D and PlexinB1 induce angiogenesis and invasive growth in colorectal cancer (CRC). The expression of Semaphorin4D (Sema4D) and PlexinB1 has been shown to be related to the prognosis of patients with various malignancies. However, the correlation between the expression of Sema4D and PlexinB1 and the relapse-free survival in patients with colorectal cancer remains controversial.

Methods

The study population included patients who underwent surgery for colorectal cancer (n = 226). The expression of Sema4D and PlexinB1 were analyzed by immunohistochemistry in tissue of stage I, II, and III colon cancers.

Results

The immunohistochemical staining of colorectal cancer tissue specimens revealed that 95 (42 %) and 105 (46.4 %) of the specimens were positive for Sema4D and PlexinB1. The expression of Sema4D and PlexinB1 respectively were both found to be significantly related to stage, depth of tumor invasion, lymph node metastasis, lymphatic invasion, and venous invasion, respectively. Sixty-three patients (27.9 %) expressed both Sema4D and PlexinB1. The positive expression of both Sema4D and PlexinB1 was found to be an independent risk factor for a worse survival (HR 1.079, CI 1.013–2.868; P = 0.044).

Conclusion

The combination of Sema4D and PlexinB1 protein detected by immunohistochemistry was therefore useful for predicting disease recurrence in CRC patients.