Semaphorin 3C Research Articles

Renal Semaphorin 3C mediates cardiac adaptive response

Abstract Cardiorenal syndrome, characterized by reciprocal heart-kidney interactions that progressively promote dysfunction in both organs, is associated with a high mortality rate. However, the mechanisms linking the two organs are insufficiently understood. Here we report that semaphorin 3C (SEMA3C) is a novel cardioprotective mediator secreted from the kidney. SEMA3C was highly expressed in the renal proximal tubules in mice. Renal Sema3c expression and circulating SEM3C were reduced by the left ventricular pressure overload that induced renal remodeling. Proximal tubule-specific secretory Sema3c deletion exacerbated cardiac hypertrophy, fibrosis and dysfunction after the pressure overload, suggesting renal SEMA3C is important for the proper cardiac adaptive response. Mechanistically, SEMA3C inhibits pathological cardiac remodeling at least partly by inhibiting Akt, ERK and Wnt/β-catenin signaling in cardiomyocytes. In heart failure patients, the plasma SEMA3C level was decreased and the low plasma SEMA3C was associated with poor cardiac outcomes. Collectively, our results show that SEMA3C produced by the kidney pivotally contributes to the cardiac stress response and its reduction contributes to the progression of heart failure. SEMA3C signaling appears to be an attractive therapeutic and diagnostic target for cardiorenal syndrome.

A Pilot Study of the Role of Semaphorin 4A (sema4A) and 3C (sema3C) in Non-Muscle-Invasive Bladder Cancer (NMIBC).

Background/Objectives: Bladder cancer is a very important issue in contemporary urology. The aim of this pilot study was to assess for the first time the clinical utility of semaphorin 3C (sema3C) and 4A (sema4A) in patients with non-muscle-invasive bladder cancer (NMIBC). Methods: The experiment involved 15 patients with NMIBC and 5 patients without malignancies as the control group. Plasma and urinary concentrations of sema3C and sema4A were assessed by using an enzyme-linked immunosorbent assay (ELISA). Urinary sema4A concentration was below the detection level. Results: There was no statistically significant difference between patients and controls in terms of plasma sema4A and sema3C or urinary sema3C concentrations (p > 0.05). There was a significantly higher sema3C plasma concentration in patients with low-grade tumors (p = 0.0132) and an upward trend in sema4A plasma concentration for the subjects with Ta-stage tumors. Urinary sema3C concentration positively correlated with tumor size (R = 0.57, p = 0.03). Plasma sema3C concentration correlated negatively with tumor grade (R = -0.62, p = 0.01). Conclusions: Urinary sema4A concentration, which is below the detection threshold, is unlikely to be useful as a marker of NMIBC. Plasma sema4A concentration and sema3C concentration in plasma and urine cannot be used as stand-alone markers of NMIBC at this point. The plasma concentration of sema3C can potentially be considered in the future as a marker for tumors of lower grades. Plasma sema4A concentration could potentially be considered in the future as a marker for tumors of earlier stages. All of these observations are preliminary, so they have to be assessed in larger cohorts to make reliable recommendations. Nevertheless, our study lays the groundwork for further research to develop potential tests that could be used in daily practice to monitor and predict the course of cancer.

Semaphorin 3C (Sema3C) reshapes stromal microenvironment to promote hepatocellular carcinoma progression

More than 90% of hepatocellular carcinoma (HCC) cases develop in the presence of fibrosis or cirrhosis, making the tumor microenvironment (TME) of HCC distinctive due to the intricate interplay between cancer-associated fibroblasts (CAFs) and cancer stem cells (CSCs), which collectively regulate HCC progression. However, the mechanisms through which CSCs orchestrate the dynamics of the tumor stroma during HCC development remain elusive. Our study unveils a significant upregulation of Sema3C in fibrotic liver, HCC tissues, peripheral blood of HCC patients, as well as sorafenib-resistant tissues and cells, with its overexpression correlating with the acquisition of stemness properties in HCC. We further identify NRP1 and ITGB1 as pivotal functional receptors of Sema3C, activating downstream AKT/Gli1/c-Myc signaling pathways to bolster HCC self-renewal and tumor initiation. Additionally, HCC cells-derived Sema3C facilitated extracellular matrix (ECM) contraction and collagen deposition in vivo, while also promoting the proliferation and activation of hepatic stellate cells (HSCs). Mechanistically, Sema3C interacted with NRP1 and ITGB1 in HSCs, activating downstream NF-kB signaling, thereby stimulating the release of IL-6 and upregulating HMGCR expression, consequently enhancing cholesterol synthesis in HSCs. Furthermore, CAF-secreted TGF-β1 activates AP1 signaling to augment Sema3C expression in HCC cells, establishing a positive feedback loop that accelerates HCC progression. Notably, blockade of Sema3C effectively inhibits tumor growth and sensitizes HCC cells to sorafenib in vivo. In sum, our findings spotlight Sema3C as a novel biomarker facilitating the crosstalk between CSCs and stroma during hepatocarcinogenesis, thereby offering a promising avenue for enhancing treatment efficacy and overcoming drug resistance in HCC.

Clinically-observed FOXA1 mutations upregulate SEMA3C through transcriptional derepression in prostate cancer

FOXA1 is a pioneer transcription factor that is frequently mutated in prostate, breast, bladder, and salivary gland malignancies. Indeed, metastatic castration-resistant prostate cancer (mCRPC) commonly harbour FOXA1 mutations with a prevalence of 35%. However, despite the frequent recurrence of FOXA1 mutations in prostate cancer, the mechanisms by which FOXA1 variants drive its oncogenic effects are still unclear. Semaphorin 3C (SEMA3C) is a secreted autocrine growth factor that drives growth and treatment resistance of prostate and other cancers and is known to be regulated by both AR and FOXA1. In the present study, we characterize FOXA1 alterations with respect to its regulation of SEMA3C. Our findings reveal that FOXA1 alterations lead to elevated levels of SEMA3C both in prostate cancer specimens and in vitro. We further show that FOXA1 negatively regulates SEMA3C via intronic cis elements, and that mutations in FOXA1 forkhead domain attenuate its inhibitory function in reporter assays, presumably by disrupting DNA binding of FOXA1. Our findings underscore the key role of FOXA1 in prostate cancer progression and treatment resistance by regulating SEMA3C expression and suggest that SEMA3C may be a driver of growth and tumor vulnerability of mCRPC harboring FOXA1 alterations.

Paired-Related Homeobox 1-Positive Cells Are Needed for Osseointegration.

To explore the contribution of paired-related homeobox 1-positive cells to the implant-induced osseointegration process in adult alveolar bone and the potential underlying mechanisms. Cre recombinase-induced lineage tracing and cell ablation were conducted in a murine dental implant model. Scratch and transwell assays were used to assess MC3T3-E1 cell migration after paired-related homeobox 1 overexpression. Single-cell RNA sequencing were applied to identify potential genes involved in pairedrelated homeobox 1-positive cells-driven osteogenesis. Paired-related homeobox 1- positive cells were observed to accumulate in the peri-implant area in a time-dependent manner. The number of these cells were found to reach its maximum on day 14. Osseointegration in mice were noticeably impaired after ablation of paired-related homeobox 1-positive cells. Further, it was discovered that paired-related homeobox 1 promotes MC3T3- E1 cell migration, a process which is indispensable for sound healing of peri-implant tissue. Finally, Semaphorin 3C was detected exclusively and abundantly expressed by paired-related homeobox 1-positive cells. Knockdown of semaphorin 3C in paired-related homeobox 1- positive cells significantly weakened their osteogenic potential. Our data suggest that paired-related homeobox 1-positive cells contribute to the osseointegration process under stress stimulation and semaphorin 3C may play a critical role in paired-related homeobox 1- positive cell-driven osteogenesis. Paired-related homeobox 1 could significantly promote MC3T3-E1 cell migration.

A genome-wide association study on hematopoietic stem cell transplantation reveals novel genomic loci associated with transplant outcomes.

Data on genomic susceptibility for adverse outcomes after hematopoietic stem cell transplantation (HSCT) for recipients are scarce. We performed a genome wide association study (GWAS) to identify genes associated with survival/mortality, relapse, and severe graft-versus-host disease (sGvHD), fitting proportional hazard and subdistributional models to data of n=1,392 recipients of European ancestry from three centres. The single nucleotide polymorphism (SNP) rs17154454, intronic to the neuronal growth guidant semaphorin 3C gene (SEMA3C), was genome-wide significantly associated with event-free survival (p=7.0x10-8) and sGvHD (p=7.5x10-8). Further associations were detected for SNPs in the Paxillin gene (PXN) with death without prior relapse or sGvHD, as well as for SNPs of the Plasmacytoma Variant Translocation 1 gene (PVT1, a long non-coding RNA gene), the Melanocortin 5 Receptor (MC5R) gene and the WW Domain Containing Oxidoreductase gene (WWOX), all associated with the occurrence of sGvHD. Functional considerations support the observed associations. Thus, new genes were identified, potentially influencing the outcome of HSCT.

Integrated bioinformatics analysis of SEMA3C in tongue squamous cell carcinoma using machine-learning strategies

Tongue squamous cell carcinoma (TSCC) is an aggressive oral cancer with a high incidence of metastasis and poor prognosis. We aim to identify and verify potential biomarkers for TSCC using bioinformatics analysis. To begin with, we examined clinical and RNA expression information of individuals with TSCC from the Gene Expression Omnibus (GEO) database. Differential expression analysis and functional analysis were conducted. Multiple machine-learning strategies were next employed to screen and determine the hub gene, and receiver operating characteristic (ROC) analysis was used to assess diagnostic value. Semaphorin3C (SEMA3C) was identified as a critical biomarker, presenting high diagnostic accuracy for TSCC. In the validation cohorts, SEMA3C exhibited high expression levels in TSCC. The high expression of SEMA3C was a poor prognostic factor in TSCC by the Kaplan–Meier curve. Based on the Gene Ontology (GO) analysis, SEMA3C was mapped in terms related to cell adhesion, positive regulation of JAK-STAT, positive regulation of stem cell maintenance, and positive regulation of NF-κB activity. Single-cell RNA sequencing (ScRNA-seq) analysis showed cells expressing SEMA3C were predominantly tumor cells. Then, we further verified that SEMA3C had high expression in TSCC clinical samples. In addition, the knockdown of SEMA3C suppressed the proliferation, migration, and invasion of TSCC cells in vitro. This study is the first to report the involvement of SEMA3C in TSCC, suggesting that upregulated SEMA3C could be a novel and critical potential biomarker for future predictive diagnostics, prevention, prognostic assessment, and personalized medical services in TSCC.

Astaxanthin Supplementation Augments the Benefits of CrossFit Workouts on Semaphorin 3C and Other Adipokines in Males with Obesity.

Regular physical activity and the use of nutritional supplements, including antioxidants, are recognized as efficacious approaches for the prevention and mitigation of obesity-related complications. This study investigated the effects of 12 weeks of CrossFit training combined with astaxanthin (ASX) supplementation on some plasma adipokines in males with obesity. Sixty-eight males with obesity (BMI: 33.6 ± 1.4 kg·m-2) were randomly assigned into four groups: the control group (CG; n = 11), ASX supplementation group (SG; n = 11), CrossFit group (TG; n = 11), and training plus supplement group (TSG; n = 11). Participants underwent 12 weeks of supplementation with ASX or placebo (20 mg/day capsule daily), CrossFit training, or a combination of both interventions. Plasma levels of semaphorin 3C (SEMA3C), apelin, chemerin, omentin1, visfatin, resistin, adiponectin, leptin, vaspin, and RBP4 were measured 72 h before the first training session and after the last training session. The plasma levels of all measured adipokines were significantly altered in SG, TG, and TSG groups (p < 0.05). The reduction of resistin was significantly higher in TSG than in SG (p < 0.05). The plasma levels of omentin1 were significantly higher in both training groups of TG and TSG than SG (p < 0.05), although such a meaningful difference was not observed between both training groups (p > 0.05). Significant differences were found in the reductions of plasma levels of vaspin, visfatin, apelin, RBP4, chemerin, and SEMA3C between the SG and TSG groups (p < 0.05). The study found that a 12-week intervention using ASX supplementation and CrossFit exercises resulted in significant improvements in several adipokines among male individuals with obesity. Notably, the combined approach of supplementation and training had the most pronounced results. The findings presented in this study indicate that the supplementation of ASX and participation in CrossFit exercise have the potential to be effective therapies in mitigating complications associated with obesity and enhancing metabolic health.

Semaphorin 3C promotes de novo steroidogenesis in prostate cancer cells.

Intratumoral androgen biosynthesis contributes to castration-resistant prostate cancer progression in patients treated with androgen deprivation therapy. The molecular mechanisms by which castration-resistant prostate cancer acquires the capacity for androgen biosynthesis to bypass androgen deprivation therapy are not entirely known. Here, we show that semaphorin 3C, a secreted signaling protein that is highly expressed in castration-resistant prostate cancer, can promote steroidogenesis by altering the expression profile of key steroidogenic enzymes. Semaphorin 3C not only upregulates enzymes required for androgen synthesis from dehydroepiandrosterone or de novo from cholesterol but also simultaneously downregulates enzymes involved in the androgen inactivation pathway. These changes in gene expression correlate with increased production of androgens induced by semaphorin 3C in prostate cancer model cells. Moreover, semaphorin 3C upregulates androgen synthesis in LNCaP cell-derived xenograft tumors, likely contributing to the enhanced in vivo tumor growth rate post castration. Furthermore, semaphorin 3C activates sterol regulatory element-binding protein, a transcription factor that upregulates enzymes involved in the synthesis of cholesterol, a sole precursor for de novo steroidogenesis. The ability of semaphorin 3C to promote intratumoral androgen synthesis may be a key mechanism contributing to the reactivation of the androgen receptor pathway in castration-resistant prostate cancer, conferring continued growth under androgen deprivation therapy. These findings identify semaphorin 3C as a potential therapeutic target for suppressing intratumoral steroidogenesis.

Association between circ_0004365 and cisplatin resistance in esophageal squamous cell carcinoma.

Cisplatin is one of the most predominant drugs for the chemotherapy of esophageal squamous cell carcinoma (ESCC); however, the underlying resistance mechanisms are still almost unknown. The present study performed RNA sequencing of human circular RNA (circRNA) in TE11 cells and cisplatin-resistant TE11 cells (TE11R). The expression profiles determined using CIRCexplorer2 revealed that the expression of circ_0004365, mapped on the Semaphorin 3C gene, was significantly greater in TE11R compared with in TE11. In reverse transcription-quantitative PCR, circ_0004365 expression was observed in human ESCC and non-tumor tissues and was significantly upregulated in ESCC tumor tissues after chemotherapy. Circ_0004365 expression was significantly upregulated in patients with poor pathological response (P=0.02). Furthermore, patients with advanced pT stage showed an upregulation in circ_0004365 expression after chemotherapy (P=0.02). The MTT assay revealed that knockdown of circ_0003465 in TE11 significantly decreased resistance to cisplatin. In conclusion, the present study suggested that circ_0004365 was associated with cisplatin resistance in ESCC and can be used as both a novel biomarker and a therapeutic target.

Semaphorin 3 C enhances putative cancer stemness and accelerates peritoneal dissemination in pancreatic cancer

PurposeSemaphorins, axon guidance cues in neuronal network formation, have been implicated in cancer progression. We previously identified semaphorin 3 C (SEMA3C) as a secreted protein overexpressed in pancreatic ductal adenocarcinoma (PDAC). We, therefore, hypothesized that SEMA3C supports PDAC progression. In this study, we aimed to investigate the clinical features of SEMA3C, especially its association with chemo-resistance and peritoneal dissemination.MethodsIn resected PDAC tissues, we assessed the relationship between SEMA3C expression and clinicopathological features by immunohistochemistry. In vitro studies, we have shown invasion assay, pancreatosphere formation assay, colony formation assay, cytotoxicity assay, and activation of SEMA3C downstream targets (c-Met, Akt, mTOR). In vivo, we performed a preclinical trial to confirm the efficacy of SEMA3C shRNA knockdown and Gemcitabine and nab-Paclitaxel (GnP) in an orthotopic transplantation mouse model and in peritoneal dissemination mouse model.ResultsIn resected PDAC tissues, SEMA3C expression correlated with invasion and peritoneal dissemination after surgery. SEMA3C promoted cell invasion, self-renewal, and colony formation in vitro. We further demonstrated that SEMA3C knockdown increased Gem-induced cytotoxicity by suppressing the activation of the Akt/mTOR pathway via the c-Met receptor. Combination therapy with SEMA3C knockdown and GnP reduced tumor growth and peritoneal dissemination.ConclusionsSEMA3C enhances peritoneal dissemination by regulating putative cancer stemness and Gem resistance and activates phosphorylation of the Akt/mTOR pathway via c-Met. Our findings provide a new avenue for therapeutic strategies in regulating peritoneal dissemination during PDAC progression.

Cleavage of semaphorin 4 C interferes with the neuroprotective effect of the semaphorin 4 C/Plexin B2 pathway on experimental intracerebral hemorrhage in rats

Semaphorin 4 C (SEMA4C) and its cognate receptor Plexin B2 are important regulators of axon guidance and are involved in many neurological diseases, in which SEMA4C acts not only as a ligand ("forward" mode) but also as a signaling receptor ("reverse" mode). However, the role of SEMA4C/Plexin B2 in intracerebral hemorrhage (ICH) remains unclear. In this study, ICH in adult male Sprague-Dawley rats was induced by autologous blood injection in the right basal ganglia. In vitro, cultured primary neurons were subjected to OxyHb to imitate ICH injury. Recombinant SEMA4C (rSEMA4C) and overexpressing lentiviruses encoding full-length SEMA4C or secretory SEMA4C (sSEMA4C) were administered to rats by intraventricular injection. First, we found that elevated levels of sSEMA4C in the cerebrospinal fluid (CSF) of clinical patients were associated with poor prognosis. Both SEMA4C and sSEMA4C were increased in brain tissue around the hematoma after ICH in rats. Overexpression of SEMA4C attenuated neuronal apoptosis, neurosis, and neurologic impairment after ICH. However, treatment with rSEMA4C or sSEMA4C overexpression exacerbated neuronal injury. In addition, when treated with SEMA4C overexpression, the forward mode downstream protein RhoA and the reverse mode downstream ID1/3 transcriptional factors of SEMA4C/Plexin B2 signaling were all activated. Nevertheless, when exposed to rSEMA4C or sSEMA4C overexpression, only the forward mode was activated. Thus, sSEMA4C may be a novel molecular biomarker to predict the prognosis of patients with ICH, and the prevention of SEMA4C cleavage is expected to be a promising therapeutic target.

Dependency of Tamoxifen Sensitive and Resistant ER+ Breast Cancer Cells on Semaphorin 3C (SEMA3C) for Growth.

Estrogen receptor positive (ER+) breast cancer (BCa) accounts for the highest proportion of breast cancer-related deaths. While endocrine therapy is highly effective for this subpopulation, endocrine resistance remains a major challenge and the identification of novel targets is urgently needed. Previously, we have shown that Semaphorin 3C (SEMA3C) is an autocrine growth factor that drives the growth and treatment resistance of various cancers, but its role in breast cancer progression and endocrine resistance is poorly understood. Here, we report that SEMA3C plays a role in maintaining the growth of ER+ BCa cells and is a novel, tractable therapeutic target for the treatment of ER+ BCa patients. Analyses of publicly available clinical datasets indicate that ER+ BCa patients express significantly higher levels of SEMA3C mRNA than other subtypes. Furthermore, SEMA3C mRNA expression was positively correlated with ESR1 mRNA expression. ER+ BCa cell lines (MCF7 and T47D) expressed higher levels of SEMA3C mRNA and protein than a normal mammary epithelial MCF10A cell line. ER siRNA knockdown was suppressed, while dose-dependent beta-estradiol treatment induced SEMA3C expression in both MCF7 and T47D cells, suggesting that SEMA3C is an ER-regulated gene. The stimulation of ER+ BCa cells with recombinant SEMA3C activated MAPK and AKT signaling in a dose-dependent manner. Conversely, SEMA3C silencing inhibited Estrogen Receptor (ER) expression, MAPK and AKT signaling pathways while simultaneously inducing apoptosis, as monitored by flow cytometry and Western blot analyses. SEMA3C silencing significantly inhibited the growth of ER+ BCa cells, implicating a growth dependency of ER+ BCa cells on SEMA3C. Moreover, the analysis of tamoxifen resistant (TamR) cell models (TamC3 and TamR3) showed that SEMA3C levels remain high despite treatment with tamoxifen. Tamoxifen-resistant cells remained dependent on SEMA3C for growth and survival. Treatment with B1SP Fc fusion protein, a SEMA3C pathway inhibitor, attenuated SEMA3C-induced signaling and growth across a panel of tamoxifen sensitive and resistant ER+ breast cancer cells. Furthermore, SEMA3C silencing and B1SP treatment were associated with decreased EGFR signaling in TamR cells. Here, our study implicates SEMA3C in a functional role in ER+ breast cancer signaling and growth that suggests ER+ BCa patients may benefit from SEMA3C-targeted therapy.

Semaphorin 4C regulates ovarian steroidogenesis through RHOA/ROCK1-mediated actin cytoskeleton rearrangement.

Semaphorins are a family of evolutionarily conserved morphogenetic molecules that were initially found to be associated with axonal guidance. Semaphorin 4C (Sema4C), a member of the fourth subfamily of semaphorins, has been demonstrated to play multifaceted and important roles in organ development, immune regulation, tumor growth, and metastasis. However, it is completely unknown whether Sema4C is involved in the regulation of ovarian function. We found that Sema4C was widely expressed in the stroma, follicles, and corpus luteum of mouse ovaries, and its expression was decreased at distinct foci in ovaries of mice of mid-to-advanced reproductive age. Inhibition of Sema4C by the ovarian intrabursal administration of recombinant adeno-associated virus-shRNA significantly reduced oestradiol, progesterone, and testosterone levels in vivo. Transcriptome sequencing analysis showed changes in pathways related to ovarian steroidogenesis and the actin cytoskeleton. Similarly, knockdown of Sema4C by siRNA interference in mouse primary ovarian granulosa cells or thecal interstitial cells significantly suppressed ovarian steroidogenesis and led to actin cytoskeleton disorganization. Importantly, the cytoskeleton-related pathway RHOA/ROCK1 was simultaneously inhibited after the downregulation of Sema4C. Furthermore, treatment with a ROCK1 agonist after siRNA interference stabilized the actin cytoskeleton and reversed the inhibitory effect on steroid hormones described above. In conclusion, Sema4C may play an important role in ovarian steroidogenesis through regulation of the actin cytoskeleton via the RHOA/ROCK1 signaling pathway. These findings shed new light on the identification of dominant factors involved in the endocrine physiology of female reproduction.

Semaphorin 4C Plays a Key Role in Colorectal Cancer Cells Development

Objective: Purpose of this work was to discuss effects and mechanisms of Sema 4C in colon cancer development. Results: Sema4C were significantly upregulated in cancer tissues (P &lt;0.001). Following transfection, the expression levels of Sema4C mRNA were significantly downregulated in the si-Sema4C groups compared with those in the si-negative control groups of both HT-29 and SW620 cells (both P &lt;0.001). The apoptotic rate was significantly increased, while the invasive and wound healing rates were significantly suppressed in the si-Sema4C groups of HT-29 and SW620 cells (both P &lt; 0.001). The results of the RT-qPCR and western blotting analyses revealed that PI3K, AKT, MMP-2 and MMP-9 mRNA and protein expression levels, respectively, were significantly downregulated, while caspase-3 mRNA and protein expression levels were significantly upregulated in the si-Sema4C groups of HT-29 and SW620 cells. Conclusion: The findings of the present study demonstrated that the knockdown of Sema4C expression suppressed CRC cell biological activities by regulating the PI3K/AKT signaling pathway. Therefore, Sema4C may act as an oncogene in CRC.

Semaphorin 4C accelerates disease progression and enables disease detection in breast cancer

Semaphorins constitute a diverse family of widely expressed transmembrane, diffusible, and GPI-linked proteins with versatile physiologic functions in orchestrating nerve system development, immune homeostasis, angiogenesis, and cell metabolism. Accumulating evidence highlights semaphorins as essential regulators of tumorigenesis by coordinating the cell-cell communications in the tumor microenvironment. Semaphorin 4C (SEMA4C) is a member of the fourth class of semaphorins with high affinity to Plexin-B2 and its interplay with cancer has long been a significant knowledge gap. Here, this perspective summarizes the recent progress in the understanding of SEMA4C in cancer and comprehensively delineates the discovery of SEMA4C in lymphatic vessels of breast cancer, the mechanisms by which SEMA4C promotes the invasiveness, proliferation, metastasis, and drug resistance of breast cancer, and the explorations of leveraging serum SEMA4C in breast cancer detection, highlighting SEMA4C as a critical driver of breast cancer progression, an effective biomarker for breast cancer diagnosis, and potential therapeutic target for breast cancer treatment.

Endothelial PlexinD1 signaling instructs spinal cord vascularization and motor neuron development

How the vascular and neural compartment cooperate to achieve such a complex and highly specialized structure as the central nervous system is still unclear. Here, we reveal a crosstalk between motor neurons (MNs) and endothelial cells (ECs), necessary for the coordinated development of MNs. By analyzing cell-to-cell interaction profiles of the mouse developing spinal cord, we uncovered semaphorin 3C (Sema3C) and PlexinD1 as a communication axis between MNs and ECs. Using cell-specific knockout mice and invitro assays, we demonstrate that removal of Sema3C in MNs, or its receptor PlexinD1 in ECs, results in premature and aberrant vascularization of MN columns. Those vascular defects impair MN axon exit from the spinal cord. Impaired PlexinD1 signaling in ECs also causes MN maturation defects at later stages. This study highlights the importance of a timely and spatially controlled communication between MNs and ECs for proper spinal cord development.

Plexin D1 negatively regulates zebrafish lymphatic development.

Lymphangiogenesis is a dynamic process that involves the directed migration of lymphatic endothelial cells (LECs) to form lymphatic vessels. The molecular mechanisms that underpin lymphatic vessel patterning are not fully elucidated and, to date, no global regulator of lymphatic vessel guidance is known. In this study, we identify the transmembrane cell signalling receptor Plexin D1 (Plxnd1) as a negative regulator of both lymphatic vessel guidance and lymphangiogenesis in zebrafish. plxnd1 is expressed in developing lymphatics and is required for the guidance of both the trunk and facial lymphatic networks. Loss of plxnd1 is associated with misguided intersegmental lymphatic vessel growth and aberrant facial lymphatic branches. Lymphatic guidance in the trunk is mediated, at least in part, by the Plxnd1 ligands, Semaphorin 3AA and Semaphorin 3C. Finally, we show that Plxnd1 normally antagonises Vegfr/Erk signalling to ensure the correct number of facial LECs and that loss of plxnd1 results in facial lymphatic hyperplasia. As a global negative regulator of lymphatic vessel development, the Sema/Plxnd1 signalling pathway is a potential therapeutic target for treating diseases associated with dysregulated lymphatic growth.

Effect of Obesity on Skeletal Muscle Semaphorin 3C Levels in Male and Female Wistar Rats

Introduction: Semaphorin 3C (Sema3C) is a relatively new and lesser-known adipokine. Recent studies have demonstrated that the class 3 semaphorin subfamilies have the most significant role in metabolic disorders. Therefore, the present study aimed to investigate the effect of obesity on skeletal muscle Sema3C levels in male and female Wistar rats. Method: In this experimental study, 12 male and female 8-week-old Wistar rats with a mean weight of 138 ± 13.60 gr were randomly assigned to two groups of six: non-obese (three males and three females) and Obese (three males and three females). The rats were dissected after eight weeks of induction of obesity and 18-20 hours of fasting, and their skeletal muscle tissue was rapidly removed and frozen. The sema3C level of skeletal muscle was measured by ELISA. Data were analyzed in SPSS software (version 21) using a two-way ANOVA test at a significance level of P≤0.0. In addition, the effect of obesity intervention was investigated in male and female rats separately. Results: Based on the results of the present study, the level of Sema3C in male and female rats in the obese group increased; nonetheless, it was not significant (P≥0.05). Moreover, Lee's index did not change significantly in male and female rats in the obese group (P≥0.05). Conclusion: It seems that a high-fat diet increases the level of Sema3C in skeletal muscle which can have negative effects on the whole body system considering the role of this adipokine in the spread of metabolic diseases

Abstract 5348: SEMA3C signaling confers resistance to Wnt Inhibition in glioblastoma

Abstract Background: Wnt signaling is widely dysregulated in cancer. The therapeutic potential of Wnt inhibitors appears promising in preclinical studies. However, they have uniformly failed clinical trials. How cancer cells develop Wnt inhibitor resistance is poorly understood. Current Wnt inhibitors are designed targeting either ligand or receptor. We hypothesized cancer cells will bypass ligand-receptor interaction through an unknown mechanism. We focused on the neurodevelopmental signaling program of Semaphorin 3C (Sema3C) that is upregulated in 85% of GBM and regulates glioma stem-cell-driven tumor progression. Methods: We analyzed the expression of Sema3C and TCF1 expression pattern in 32 human GBM samples by immunohistochemistry. GSC self-renewal was assessed by extreme limiting dilution, Edu incorporation, tumorsphere formation and cell survival assays in Sema3C silencing GSCs. Cell fractionation and immunofluorescence studies were performed to assess β-catenin sub-cellular localization in GSCs. GSC-derived mouse models were assessed for survival. Results: Porcupine inhibitor LGK974 reduced TCF1 expression in the GBM tumor mouse models, suggesting successful target engagement in vivo. However, it failed to prolong the overall survival. Sema3C expression strongly correlated with TCF1 expression in human GBM samples by immunohistochemical analysis. Genetic inhibition of Sema3C and TCF1 together prolonged animal survival more than either alone, indicating better control of Wnt pathway signaling with dual pathway blockade. Immunofluorescence and cell fractionation studies revealed that Sema3C signaling drove β-catenin nuclear accumulation. Sema3C regulates transactivation of Wnt target genes including TCF1, c-Myc and c-Met. Sema3C pathway activates Rac1. It is reported that Rac1 activates β-catenin and promotes β-catenin nuclear accumulation. In GSCs, constitutively active Rac1 restored β-catenin nuclear localization and rescued TCF1 and c-Myc down-regulation in the setting of Sema3C silencing. Sema3C can drive canonical Wnt signaling even when Wnt ligand secretion is blocked. Together, the data support that GSCs can escape Wnt inhibition through Sema3C and Rac1. Conclusions: Sema3C signaling drives canonical Wnt signaling, providing an escape mechanism for cancer cells despite Wnt ligand-receptor interruption. Sema3C-β-catenin signaling promotes GSC self-renewal and tumor progression. Upstream Wnt pathway inhibition alone is insufficient to control tumors. Our data provide a therapeutic strategy of dual blockade of Wnt and Sema3C pathways to provide clinically significant tumor control. Citation Format: Jing Hao. SEMA3C signaling confers resistance to Wnt Inhibition in glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5348.