Semaphorin 3A suppresses tumor growth and metastasis in mice melanoma model

The Involvement of Semaphorins in the Pathogenesis of Skin Diseases

Semaphorins belong to a group of membrane and secretory proteins that act as ligands for several receptor families and are involved in modulating cell signaling pathways. They bind multimeric receptor complexes on the cell membrane to exert their effects and initiate unique intracellular signal transduction cascades. These proteins can influence several processes that are very important for cell function, such as cell division and differentiation. Semaphorins are involved in cell migration, apoptosis, cell adhesion, aggregation, and numerous immune processes due to their immunoregulatory effects. Semaphorins are expressed in keratinocytes, which is why they have become a target for studies on the pathogenesis of skin diseases. Most studies to date on the role of semaphorins in the pathogenesis of skin diseases have been carried out in cellular or animal models, and there are few clinical studies evaluating the role of semaphorins in the pathogenesis and therapy of skin diseases. In this narrative review, we summarized the current state of knowledge on the role of semaphorins in the pathogenesis of skin diseases and their potential importance as targets for therapy. We also tried to present the key findings and weaknesses of previous research in this field. The novelty of this article lies in the comprehensive presentation of the role of semaphorins in the pathogenesis of skin diseases, including the results of studies on cell cultures and animal models, elucidating the mechanisms and signaling pathways through which semaphorins affect the development of skin diseases, as well as on the presentation of the results of existing clinical trials evaluating the role of semaphorins in the pathogenesis of skin diseases, and as potential therapeutic targets.

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.

Neuropilin 1 regulates bone marrow vascular regeneration and hematopoietic reconstitution

Ionizing radiation and chemotherapy deplete hematopoietic stem cells and damage the vascular niche wherein hematopoietic stem cells reside. Hematopoietic stem cell regeneration requires signaling from an intact bone marrow (BM) vascular niche, but the mechanisms that control BM vascular niche regeneration are poorly understood. We report that BM vascular endothelial cells secrete semaphorin 3 A (SEMA3A) in response to myeloablation and SEMA3A induces p53 - mediated apoptosis in BM endothelial cells via signaling through its receptor, Neuropilin 1 (NRP1), and activation of cyclin dependent kinase 5. Endothelial cell - specific deletion of Nrp1 or Sema3a or administration of anti-NRP1 antibody suppresses BM endothelial cell apoptosis, accelerates BM vascular regeneration and concordantly drives hematopoietic reconstitution in irradiated mice. In response to NRP1 inhibition, BM endothelial cells increase expression and secretion of the Wnt signal amplifying protein, R spondin 2. Systemic administration of anti - R spondin 2 blocks HSC regeneration and hematopoietic reconstitution which otherwise occurrs in response to NRP1 inhibition. SEMA3A - NRP1 signaling promotes BM vascular regression following myelosuppression and therapeutic blockade of SEMA3A - NRP1 signaling in BM endothelial cells accelerates vascular and hematopoietic regeneration in vivo.

Neuropilin-1: a checkpoint target with unique implications for cancer immunology and immunotherapy

Checkpoint blockade immunotherapy established a new paradigm in cancer treatment: for certain patients curative treatment requires immune reinvigoration. Despite this monumental advance, only 20%–30% of patients achieve an objective response to standard of care immunotherapy, necessitating the consideration of alternative targets. Optimal strategies will not only stimulate CD8⁺ T cells, but concomitantly modulate immunosuppressive cells in the tumor microenvironment (TME), most notably regulatory T cells (T_reg cells). In this context, the immunoregulatory receptor Neuropilin-1 (NRP1) is garnering renewed attention as it reinforces intratumoral T_reg cell function amidst inflammation in the TME. Loss of NRP1 on T_reg cells in mouse models restores antitumor immunity without sacrificing peripheral tolerance. Enrichment of NRP1⁺ T_reg cells is observed in patients across multiple malignancies with cancer, both intratumorally and in peripheral sites. Thus, targeting NRP1 may safely undermine intratumoral T_reg cell fitness, permitting enhanced inflammatory responses with existing immunotherapies. Furthermore, NRP1 has been recently found to modulate tumor-specific CD8⁺ T cell responses. Emerging data suggest that NRP1 restricts CD8⁺ T cell reinvigoration in response to checkpoint inhibitors, and more importantly, acts as a barrier to the long-term durability of CD8⁺ T cell-mediated tumor immunosurveillance. These novel and distinct regulatory mechanisms present an exciting therapeutic opportunity. This review will discuss the growing literature on NRP1-mediated immune modulation which provides a strong rationale for categorizing NRP1 as both a key checkpoint in the TME as well as an immunotherapeutic target with promise either alone or in combination with current standard of care therapeutic regimens.

Interactions between semaphorins and plexin-neuropilin receptor complexes in the membranes of live cells

Signaling of semaphorin ligands via their plexin–neuropilin receptors is involved in tissue patterning in the developing embryo. These proteins play roles in cell migration and adhesion but are also important in disease etiology, including in cancer angiogenesis and metastasis. While some structures of the soluble domains of these receptors have been determined, the conformations of the full-length receptor complexes are just beginning to be elucidated, especially within the context of the plasma membrane. Pulsed-interleaved excitation fluorescence cross-correlation spectroscopy allows direct insight into the formation of protein–protein interactions in the membranes of live cells. Here, we investigated the homodimerization of neuropilin-1 (Nrp1), plexin A2, plexin A4, and plexin D1 using pulsed-interleaved excitation fluorescence cross-correlation spectroscopy. Consistent with previous studies, we found that Nrp1, plexin A2, and plexin A4 are present as dimers in the absence of exogenous ligand. Plexin D1, on the other hand, was monomeric under similar conditions, which had not been previously reported. We also found that plexin A2 and A4 assemble into a heteromeric complex. Stimulation with semaphorin 3A or semaphorin 3C neither disrupts nor enhances the dimerization of the receptors when expressed alone, suggesting that activation involves a conformational change rather than a shift in the monomer–dimer equilibrium. However, upon stimulation with semaphorin 3C, plexin D1 and Nrp1 form a heteromeric complex. This analysis of interactions provides a complementary approach to the existing structural and biochemical data that will aid in the development of new therapeutic strategies to target these receptors in cancer.

SEMAPHORINS and their receptors: focus on the crosstalk between melanoma and hypoxia

Hypoxia, a condition of oxygen deprivation, is considered a hallmark of tumor microenvironment regulating several pathways and promoting cancer progression and resistance to therapy. Semaphorins, a family of about 20 secreted, transmembrane and GPI-linked glycoproteins, and their cognate receptors (plexins and neuropilins) play a pivotal role in the crosstalk between cancer and stromal cells present in the tumor microenvironment. Many studies reported that some semaphorins are involved in the development of a permissive tumor niche, guiding cell-cell communication and, consequently, the development and progression, as well as the response to therapy, of different cancer histotypes, including melanoma.

In this review we will summarize the state of art of semaphorins regulation by hypoxic condition in cancer with different origin. We will also describe evidence about the ability of semaphorins to affect the expression and activity of transcription factors activated by hypoxia, such as hypoxia-inducible factor-1. Finally, we will focus our attention on findings reporting the role of semaphorins in melanocytes transformation, melanoma progression and response to therapy. Further studies are necessary to understand the mechanisms through which semaphorins induce their effect and to shed light on the possibility to use semaphorins or their cognate receptors as prognostic markers and/or therapeutic targets in melanoma or other malignancies.

Expression of Semaphorin 3A in Malignant and Normal Bladder Tissue: Immunohistochemistry Staining and Morphometric Evaluation

Simple Summary

Semaphorin 3A (Sema3A) was shown to play a significant role in different neoplasms. In a previous study by our team, we showed that Sema3A is overexpressed in patients with urothelial carcinoma (UC). In this study, we analyzed 43 specimens from patients with the entire spectrum of UC and compared them with samples from 14 normal urothelium using immunostaining and computerized morphometry. The results showed that patients with UC had intense Sema3A staining in the apical layer of the mucosa compared to patients without UC. Moreover, patients with higher grade UC showed intense Sema3A staining across all mucosal layers.

Abstract

Introduction: Our previous studies showed elevated levels of Semaphorin3a (Sema3A) in the urine of patients with urothelial cancer compared to healthy patients. The aim of this study was to analyze the extent of Sema3A expression in normal and malignant urothelial tissue using immune-staining microscopic and morphometric analysis. Materials and Methods: Fifty-seven paraffin-embedded bladder samples were retrieved from our pathology archive and analyzed: 14 samples of normal urothelium, 21 samples containing low-grade urothelial carcinoma, 13 samples of patients with high-grade urothelial carcinoma, 7 samples containing muscle invasive urothelial carcinoma, and 2 samples with pure urothelial carcinoma in situ. All samples were immunostained with anti Sema3A antibodies. The area of tissue stained with Sema3A and its intensity were analyzed using computerized morphometry and compared between the samples’ groups. Results: In normal bladder tissue, very light Sema3A staining was demonstrated on the mucosal basal layer and completely disappeared on the apical layer. In low-grade tumor samples, cells in the basal layer of the mucosa were also lightly stained with Sema3A, but Seama3A expression intensified upon moving apically, reaching its highest level on apical cells exfoliating to the urine. In high grade urothelial tumors, Seama3A staining was intense in the entire thickness of the mucosa. In samples containing carcinoma in situ, staining intensity was high and homogenous in all the neoplastic cells. Conclusions: Sema3A may be serve as a potential non-invasive marker of urothelial cancer.

Class-3 semaphorins: Potent multifunctional modulators for angiogenesis-associated diseases

Semaphorins, the neuronal guidance cues, were shown to have broad influences on pathophysiological processes such as bone remodeling, immune responses, and angiogenesis. In particular, Class-3 Semaphorins (SEMA3) is considered a vital regulator involved in angiogenesis. Scientific evidence has pointed to the role of angiogenesis in many diseases, and numerous efforts have been made to explore the possibilities of curing those diseases by targeting angiogenesis. Nevertheless, the efficacies are limited owing to the complex mechanisms of angiogenesis. Hence, investigating the mechanisms of SEMA3 in angiogenesis may contribute to novel therapeutics for diseases. Previous reviews mainly focused on the various functions of semaphorins in one particular disease, and the specific angiogenesis mechanism of SEMA3 in diverse diseases has not been well elucidated. Additionally, the role of SEMA3 in angiogenesis remains elusive, as contradicting results have been found in different disease types. Some evidence from recent studies implies that, while most SEMA3 molecules inhibit pathological angiogenesis in different diseases, occasionally SEMA3 may also promote angiogenesis. This review summarizes the specific role of SEMA3 in a variety of angiogenesis-associated diseases, and documents SEMA3 may be a promising therapeutic target for treating angiogenesis-associated diseases.

Vascular endothelial growth factor/semaphorin-3A ratio and SEMA3A expression in cutaneous malignant melanoma

Breslow thickness and Clark level are still important factors for cutaneous melanoma, but do not provide a precise prognosis in all cases. It is necessary to find new factors capable of a more accurate prediction of the tumor course. Angiogenesis is essential for tumor development and progression and is regulated by vascular endothelial growth factor A (VEGF-A) and semaphorins (SEMA), in particular, SEMA3A inhibits angiogenesis by affecting VEGF signaling. However, the prognostic role of angiogenetic factors remains unclear. To date, no information is available on SEMA3A in human melanoma. Microvessel density, immunohistochemical and mRNA VEGF and SEMA3A expression level in 60 thin (Breslow thickness ≤ 1.0 mm), 60 intermediate (1.1-4.0 mm) and 50 thick (>4.0 mm) primary human cutaneous melanomas were investigated and related to clinical/pathological parameters and disease-specific survival. No positive association between Breslow thickness, Clark level, metastasis presence and survival was identified; Clark level was poorly related to survival. VEGF and microvessel density were significantly higher in intermediate and thick melanomas and related to Breslow thickness and Clark level but not to metastasis status and survival. On the contrary, SEMA3A was significantly reduced in intermediate and thick melanomas and associated to metastasis and poor survival. VEGF/SEMA3A ratio was higher in the worst prognosis, resulting the most closely related factor with metastasis and survival. SEMA3A expression and VEGF/SEMA3A ratio turned out to be valuable prognostic biomarkers in patients affected by cutaneous melanoma, in particular with Breslow thickness >1 mm. SEMA3A might serve as a candidate tumor suppressor in cutaneous melanoma therapy.

Characterization of Class-3 Semaphorin Receptors, Neuropilins and Plexins, as Therapeutic Targets in a Pan-Cancer Study

Class-3 semaphorins (SEMA3s), initially characterized as axon guidance cues, have been recognized as key regulators for immune responses, angiogenesis, tumorigenesis and drug responses. The functions of SEMA3s are attributed to the activation of downstream signaling cascades mainly mediated by cell surface receptors neuropilins (NRPs) and plexins (PLXNs), yet their roles in human cancers are not completely understood. Here, we provided a detailed pan-cancer analysis of NRPs and PLXNs in their expression, and association with key signal transducers, patient survival, tumor microenvironment (TME), and drug responses. The expression of NRPs and PLXNs were dysregulated in many cancer types, and the majority of them were further dysregulated in metastatic tumors, indicating a role in metastatic progression. Importantly, the expression of these genes was frequently associated with key transducers, patient survival, TME, and drug responses; however, the direction of the association varied for the particular gene queried and the specific cancer type/subtype tested. Specifically, NRP1, NRP2, PLXNA1, PLXNA3, PLXNB3, PLXNC1, and PLXND1 were primarily associated with aggressive phenotypes, whereas the rest were more associated with favorable prognosis. These data highlighted the need to study each as a separate entity in a cancer type- and subtype-dependent manner.

Curcumin and LOXblock-1 ameliorate ischemia-reperfusion induced inflammation and acute kidney injury by suppressing the semaphorin-plexin pathway

AIMS

Ischemia/reperfusion (I/R) is one of the most important causes of acute kidney injury (AKI), a clinical syndrome with kidney dysfunction and high mortality rates. New diagnostic biomarkers need to be defined to better illuminate the pathophysiology of AKI. For the first time, we aim to investigate the protective effects of Curcumin which is known for its antioxidant and anti-inflammatory properties and 12/15 lipoxygenase inhibitor LOXblock-1 on I/R induced AKI by modulating inflammatory processes, oxidative stress, apoptosis and semaphorin-plexin pathway.

MAIN METHODS

The rats were divided into five groups, with eight animals per group: Sham, I/R, I/R + DMSO (1%, i.p.), I/R + Curcumin (100 mg/kg, i.p.), I/R + LOXblock-1 (2 μg/kg, i.p.).

KEY FINDINGS

The renal function biomarkers (BUN, CREA and UA) in serum were significantly increased in the I/R group. The inflammatory (TNF-α, IL-6 and MCP-1), apoptotic (CYCS and CASP3) and oxidative stress parameters (MDA, MPO, TAS and TOS) measured by ELISA were significantly increased in the I/R group. In histopathological analysis, it was observed that I/R caused serious damage to kidney tissue. SEMA3A was found to increase both serum level and mRNA expression in I/R group. It was observed that curcumin and LOXblock-1 reduce inflammatory processes, oxidative stress and apoptosis via the semaphorin-plexin pathway by both measurements and histopathological analysis. Curcumin was proved more effective than LOXblock-1 with its antioxidant feature in I/R injury.

SIGNIFICANCE

The current study reveals the protective effects of Curcumin and LOXblock-1 on acute kidney injury by suppressing SEMA3A as a new biomarker.

The Role of a Proprotein Convertase Inhibitor in Reactivation of Tumor-Associated Macrophages and Inhibition of Glioma Growth

Tumors are characterized by the presence of malignant and non-malignant cells, such as immune cells including macrophages, which are preponderant. Macrophages impact the efficacy of chemotherapy and may lead to drug resistance. In this context and based on our previous work, we investigated the ability to reactivate macrophages by using a proprotein convertases inhibitor. Proprotein convertases process immature proteins into functional proteins, with several of them having a role in immune cell activation and tumorigenesis. Macrophages were treated with a peptidomimetic inhibitor targeting furin, PC1/3, PC4, PACE4, and PC5/6. Their anti-glioma activity was analyzed by mass spectrometry-based proteomics and viability assays in 2D and 3D in vitro cultures. Comparison with temozolomide, the drug used for glioma therapy, established that the inhibitor was more efficient for the reduction of cancer cell density. The inhibitor was also able to reactivate macrophages through the secretion of several immune factors with antitumor properties. Moreover, two proteins considered as good glioma patient survival indicators were also identified in 3D cultures treated with the inhibitor. Finally, we established that the proprotein convertases inhibitor has a dual role as an anti-glioma drug and anti-tumoral macrophage reactivation drug. This strategy could be used together with chemotherapy to increase therapy efficacy in glioma.

Nrp1 is Activated by Konjac Ceramide Binding-Induced Structural Rigidification of the a1a2 Domain

Konjac ceramide (kCer) is a plant-type ceramide composed of various long-chain bases and α-hydroxyl fatty acids. The presence of d4t,8t-sphingadienine is essential for semaphorin 3A (Sema3A)-like activity. Herein, we examined the three neuropilin 1 (Nrp1) domains (a1a2, b1b2, or c), and found that a1a2 binds to d4t,8t-kCer and possesses Sema3A-like activity. kCer binds to Nrp1 with a weak affinity of μM dissociation constant (Kd). We wondered whether bovine serum albumin could influence the ligand–receptor interaction that a1a2 has with a single high affinity binding site for kCer (Kd in nM range). In the present study we demonstrated the influence of bovine serum albumin. Thermal denaturation indicates that the a1a2 domain may include intrinsically disordered region (IDR)-like flexibility. A potential interaction site on the a1 module was explored by molecular docking, which revealed a possible Nrp1 activation mechanism, in which kCer binds to Site A close to the Sema3A-binding region of the a1a2 domain. The a1 module then accesses a2 as the IDR-like flexibility becomes ordered via kCer-induced protein rigidity of a1a2. This induces intramolecular interaction between a1 and a2 through a slight change in protein secondary structure.

Neuropilin: Handyman and Power Broker in the Tumor Microenvironment

Neuropilin-1 and neuropilin-2 form a small family of transmembrane receptors, which, due to the lack of a cytosolic protein kinase domain, act primarily as co-receptors for various ligands. Performing at the molecular level both the executive and organizing functions of a handyman as well as of a power broker, they are instrumental in controlling the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. In this setting, the various neuropilin ligands and interaction partners on various cells of the tumor microenvironment, such as cancer cells, endothelial cells, cancer-associated fibroblasts, and immune cells, are surveyed. The suitability of various neuropilin-targeting substances and the intervention in neuropilin-mediated interactions is considered as a possible building block of tumor therapy.

Significance of BRCA2 and RB1 Co-loss in Aggressive Prostate Cancer Progression

PURPOSE

Previous sequencing studies revealed that alterations of genes associated with DNA damage response (DDR) are enriched in men with metastatic castration-resistant prostate cancer (mCRPC). BRCA2, a DDR and cancer susceptibility gene, is frequently deleted (homozygous and heterozygous) in men with aggressive prostate cancer. Here we show that patients with prostate cancer who have lost a copy of BRCA2 frequently lose a copy of tumor suppressor gene RB1; importantly, for the first time, we demonstrate that co-loss of both genes in early prostate cancer is sufficient to induce a distinct biology that is likely associated with worse prognosis.

EXPERIMENTAL DESIGN

We prospectively investigated underlying molecular mechanisms and genomic consequences of co-loss of BRCA2 and RB1 in prostate cancer. We used CRISPR-Cas9 and RNAi-based methods to eliminate these two genes in prostate cancer cell lines and subjected them to in vitro studies and transcriptomic analyses. We developed a 3-color FISH assay to detect genomic deletions of BRCA2 and RB1 in prostate cancer cells and patient-derived mCRPC organoids.

RESULTS

In human prostate cancer cell lines (LNCaP and LAPC4), loss of BRCA2 leads to the castration-resistant phenotype. Co-loss of BRCA2-RB1 in human prostate cancer cells induces an epithelial-to-mesenchymal transition, which is associated with invasiveness and a more aggressive disease phenotype. Importantly, PARP inhibitors attenuate cell growth in human mCRPC-derived organoids and human CRPC cells harboring single-copy loss of both genes.

CONCLUSIONS

Our findings suggest that early identification of this aggressive form of prostate cancer offers potential for improved outcomes with early introduction of PARP inhibitor-based therapy.See related commentary by Mandigo and Knudsen, p. 1784.

Semaphorin 6A Attenuates the Migration Capability of Lung Cancer Cells via the NRF2/HMOX1 Axis

Cell migration is a fundamental feature of cancer recurrence. Since recurrence is correlated with high mortality in lung cancer, it follows that reducing cell migration would decrease recurrence and increase survival rates. Semaphorin-6A (SEMA6A), a protein initially known as a regulator of axonal guidance, is down-regulated in lung cancer tissue, and low levels of SEMA6A are associated with cancer recurrence. Thus, we hypothesized that SEMA6A could suppress cancer cell migration. In this study, we found that the migration capability of H1299 lung cancer cells decreased with SEMA6A overexpression, while it increased with SEMA6A silencing. Moreover, silencing of the cellular homeostasis protein Heme-oxygenase-1 (HMOX1) and/or the transcription factor Nuclear Factor, Erythroid-2-Like-2 (NRF2) reversed the migration-suppressing effect of SEMA6A and the SEMA6A-driven alterations in expression of urokinase insulin-like-growth-factor-binding-protein-3, Matrix metalloproteinase (MMP)-1, and MMP9, the downstream effectors of HMOX1. Taken together, these results demonstrate that SEMA6A is a potential suppressor of cancer migration that functions through the NRF2/HMOX1 axis. Our results explain why low SEMA6A is linked to high recurrence in the clinical setting and suggest that SEMA6A could be useful as a biomarker or target in lung cancer therapy.

MicroRNA-192-5p Promote the Proliferation and Metastasis of Hepatocellular Carcinoma Cell by Targeting SEMA3A

Side population (SP) cells are a small subset of cells isolated from a cultured cancer cell line with characteristics similar to those of cancer stem cells, such as high metastatic and tumorigenic potentials. However, the molecular mechanisms remain unclear for the malignant properties of SP cells. In this study, SP cells were isolated by staining cultured HCCLM3 cells with fluorescent DNA-binding dye Hoechst 33342 and sorted by flow cytometry. The proportion of SP cells was 2.79%±0.19% in the HCCLM3 cell line. Compared with non-SP cells, SP cells possessed stronger capability of sphere formation and tumorigenicity, and expressed higher levels of CD133 and CD90. Then, we found that SP cells possessed 25 upregulated and 34 downregulated microRNAs with differences of >3-fold. As one of the upregulated microRNAs, miR-192-5p was computationally predicted to target semaphorin 3A (SEMA3A), a potent suppressor of tumor angiogenesis in various cancer models. Luciferase reporter assay showed that SEMA3A was a direct target of miR-192-5p. Overexpression of miR-192-5p promoted cell proliferation and metastasis targeting SEMA3A in HCCLM3 cells. Immunohistochemical staining revealed that SEMA3A expression was significantly reverse associated with metastasis in hepatocellular carcinoma tissues. The results indicate that miR-192-5p contributes to targeting SEMA3A in HCCLM3 cells, and this may be used as a target in targeted therapy and a marker for cancer behavior and prognosis.

The Prognostic Value of Serum Semaphorin3A and VEGF Levels in Patients with Metastatic Colorectal Cancer

PURPOSE

Despite new treatment options in metastatic colorectal cancer (mCRC), new prognostic markers are still needed to determine optimal chemoregimen especially for anti-angiogenesis drugs. In this study, we evaluated the serum semaphorin and VEGF-A levels as prognostic factors in patients with mCRC.

METHODS

Patients with diagnosed mCRC who were treated with first-line bevacizumab plus chemotherapy were included in the study. Venous blood samples of 37 patients with metastatic colon cancer were taken, and serum semaphorin 3A and VEGF-A levels were studied in pre-treatment and the 1st and third months after the treatment was initiated.

RESULTS

Totally, 37 patients were enrolled in the study. The patients' mean age was 62 years. Twenty-eight (49%) of the patients were male, and 19 (51%) were female. Serum semaphorin3A (sema3A) levels of the patients were 5.4 ± 7.4 ng/ml before the treatment, 3.5 ± 3.3 ng/ml at the first month, and 3.5 ± 3.7 ng/ml at the third month. Serum VEGF-A levels were 27.7 ± 32.9 ng/l before the treatment, 23.1 ± 28.1 ng/l at the first month, and 28.9 ± 30.2 ng/l at the third month. There was no significant correlation between the survival and pre-treatment VEGF-A level (p = 0.064). Overall survival (OS) was statistically significantly higher in patients with pre-treatment semaphorin 3A levels below 5.4 ng/ml than higher than 5.4 ng/ml (10.5 months vs 4.5 months, respectively, HR 0.23, 95% CI 19.635-11,391, p = 0.012).

CONCLUSION

Pre-treatment semaphorin 3A level can be a prognostic marker for the mCRC patients who were treated with bevacizumab in patients with metastatic colorectal cancer.

Bio-derived hydroxystearic acid ameliorates skin age spots and conspicuous pores

INTRODUCTION

We report on the preparation and efficacy of 10-hydroxystearic acid (HSA) that improves facial age spots and conspicuous pores.

METHODS

The hydration of oleic acid into HSA was catalyzed by the oleate hydratase from Escherichia coli. Following treatment with HSA, collagen type I and type III was assessed in primary human dermal fibroblasts together with collagen type III, p53 protein levels and sunburn cells (SBC) after UVB irradiation (1 J cm^-2 ) by immunohistochemistry on human ex vivo skin. UVB-induced expression of matrix metalloprotease-1 (MMP-1) was determined from full thickness skin by RT-qPCR. Modification of the fibroblast secretome by HSA was studied by mass-spectrometry-based proteomics. In a full-face, double blind, vehicle-controlled trial HSA was assessed for its effects on conspicuous facial pore size and degree of pigmentation of age spots in Caucasian women over an 8-week period.

RESULTS

HSA was obtained in enantiomeric pure, high yield (≥80%). Collagen type I and type III levels were dose-dependently increased (96% and 244%; P < 0.01) in vitro and collagen type III in ex vivo skin by +57% (P < 0.01) by HSA. HSA also inhibited UVB-induced MMP-1 gene expression (83%; P < 0.01) and mitigated SBC induction (-34% vs. vehicle control) and reduced significantly UV-induced p53 up-regulation (-46% vs. vehicle control; P < 0.01) in irradiated skin. HSA modified the fibroblast secretome with significant increases in proteins associated with the WNT pathway that could reduce melanogenesis and proteins that could modify dermal fibroblast activity and keratinocyte differentiation to account for the alleviation of conspicuous pores. Docking studies in silico and EC50 determination in reporter gene assays (EC50 5.5 × 10^-6  M) identified HSA as a peroxisomal proliferator activated receptor-α (PPARα) agonist. Clinically, HSA showed a statistically significant decrease of surface and volume of skin pores (P < 0.05) after 8 weeks of application and age spots became significantly less pigmented than the surrounding skin (contrast, P < 0.05) after 4 weeks.

CONCLUSION

HSA acts as a PPARα agonist to reduce the signs of age spots and conspicuous pores by significantly modulating the expression of p53, SBC, MMP-1 and collagen together with major changes in secreted proteins that modify keratinocyte, melanocyte and fibroblast cell behavior.

Semaphorin-3A inhibits multiple myeloma progression in a mouse model

Previous studies revealed that progression of multiple myeloma (MM) is associated with downregulation of semaphorin-3A (sema3A) expression in bone marrow endothelial cells. We therefore determined if serum sema3A concentrations are correlated with MM progression and if sema3A can affect MM progression. We find that the concentration of sema3A in sera of MM patients is strongly reduced and that the decrease is correlated with disease progression. A similar depletion is found in patients having acute myeloid leukemia and acute lymphoblastic leukemia but not in cancer forms that do not involve the bone marrow such as in colon cancer. Expression of a modified sema3A [furin-resistant sema3A (FR-sema3A)] stabilized against cleavage by furin-like proprotein convertases in CAG MM cells did not affect their behavior in-vitro. CAG cells injected into the tail vein of severe combined immunodeficient (SCID) mice home to the bone marrow and proliferate, mimicking MM disease progression. Disease progression in mice injected with CAG cells expressing FR-sema3A was inhibited, resulting in prolonged survival and a lower incidence of bone lesions. Histological examination and fluorescence-activated cell sorting analysis revealed that FR-sema3A expression reduced the infiltration of the CAG cells into the bone marrow, reduced bone marrow necrosis and reduced angiogenesis induced by the MM cells in the bone marrow. Our results suggest that measurement of sema3A serum concentrations may be of use for the diagnosis and for the monitoring of malignancies of the bone marrow such as MM. Furthermore, our results suggest that FR-sema3A may perhaps find use as an inhibitor of MM disease progression.

Penalized integrative semiparametric interaction analysis for multiple genetic datasets

In this article, we consider a semiparametric additive partially linear interaction model for the integrative analysis of multiple genetic datasets. The goals are to identify important genetic predictors and gene-gene interactions and to estimate the nonparametric functions that describe the environmental effects at the same time. To find the similarities and differences of the genetic effects across different datasets, we impose a group structure on the regression coefficients matrix under the homogeneity assumption, ie, models for different datasets share the same sparsity structure, but the coefficients may differ across datasets. We develop an iterative approach to estimate the parameters of main effects, interactions and nonparametric functions, where a reparametrization of interaction parameters is implemented to meet the strong hierarchy assumption. We demonstrate the advantages of the proposed method in identification, estimation, and prediction in a series of numerical studies. We also apply the proposed method to the Skin Cutaneous Melanoma data and the lung cancer data from the Cancer Genome Atlas.

Neuropilins in the Context of Tumor Vasculature

Neuropilin-1 and Neuropilin-2 form a small family of plasma membrane spanning receptors originally identified by the binding of semaphorin and vascular endothelial growth factor. Having no cytosolic protein kinase domain, they function predominantly as co-receptors of other receptors for various ligands. As such, they critically modulate the signaling of various receptor tyrosine kinases, integrins, and other molecules involved in the regulation of physiological and pathological angiogenic processes. This review highlights the diverse neuropilin ligands and interacting partners on endothelial cells, which are relevant in the context of the tumor vasculature and the tumor microenvironment. In addition to tumor cells, the latter contains cancer-associated fibroblasts, immune cells, and endothelial cells. Based on the prevalent neuropilin-mediated interactions, the suitability of various neuropilin-targeted substances for influencing tumor angiogenesis as a possible building block of a tumor therapy is discussed.

A Preliminary Study of the Effect of Semaphorin 3A and Acitretin on the Proliferation, Migration, and Apoptosis of HaCaT Cells

Background:

Vascular endothelial growth factor (VEGF) is significantly elevated in psoriatic patients and is associated with the severity of the psoriasis. Due to the effect of inhibiting production of VEGF, acitretin can effectively treat psoriasis. Semaphorin 3A (Sema3A) restrain tumor growth and angiogenesis by partially reversing VEGF effects on tumor. However, the role of Sema3A in the pathogenesis of psoriasis is unclear.

Aims and Objectives:

This study aimed to investigate the effect of VEGF, Sema3A, and acitretin on HaCaT cells, to see whether Sema3A could be a beneficial factor in psoriasis, as well as acitretin.

Materials and Methods:

Functional analysis of VEGF, Sema3A, and acitretin was carried out using HaCaT cells cultured under different treatments. Cell counting kit-8 method, colony formation assay, flow cytometry, transwell migration, reverse transcription-polymerase chain reaction, and Western blot test were performed to measure proliferation, colony formation, migration, apoptosis, and the expression of Bcl2, Bax, Caspase 3, and Caspase 9 of HaCaT cells.

Results:

Sema3A and acitretin inhibited the proliferation, colony formation, and migration of HaCaT cells, while induced the apoptosis of HaCaT cells by inhibiting the expression of Bcl2, and promoting the expression of Bax, Caspase 3, and Caspase 9, which were opposite to VEGF. Sema3A and acitretin partially reversed the function of VEGF.

Conclusions:

Like acitretin, exogenous supplement of Sema3A may correct the abnormal proliferation and apoptosis procedure of HaCaT cells, and partially reverse the function of VEGF.

Overexpression of Semaphorin-3A and Semaphorin-4D in the Peripheral Blood from Newly Diagnosed Patients with Chronic Lymphocytic Leukemia

Background: Semaphorins play prominent roles in physiological and pathological processes such as vascular development, tumor growth and immune responses. Semaphorins have different roles in various kinds of cancers, but there is no study concerning their expression in the chronic lymphocytic leukemia (CLL). This study aimed to assess the SEMA3A, SEMA4A and SEMA4D expression in patients with CLL. Materials and Methods: Peripheral blood specimens were collected from 30 newly-diagnosed untreated patients with CLL and 30 healthy subjects as a control group. The SEMA3A, SEMA4A and SEMA4D expression was determined by real-time PCR method. Results: The fold change expression of SEMA3A and SEMA4D was 7.58 ± 2.66 and 3.20 ± 0.99 in patients with CLL, and was 1.01 ± 0.31 and 1.00 ± 0.27 in healthy subjects, respectively. The CLL patients expressed higher amounts of SEMA3A and SEMA4D in comparison with healthy subjects (P<0.02 and P<0.03, respectively). The fold change expression of SEMA3A in patients with stage II (11.12 ± 5.35) was also higher than patients with stage I (4.49 ± 1.61, P<0.05). No significant difference was also observed in the expression of SEMA4A and SEMA4D between patients with stage I and stage II CLL. In both CLL and control groups, the fold change expression of SEMA3A was higher in men than in women (P<0.03 and P<0.02, respectively). Conclusion: The results of the study indicated elevated expression of the SEMA3A and SEMA4D in patients with CLL. The SEMA3A expression was influenced by tumor stage and gender of participants.

Targeting Semaphorin 3C in Prostate Cancer With Small Molecules

Despite the amenability of early-stage prostate cancer to surgery and radiation therapy, locally advanced and metastatic prostate cancer is clinically problematic. Chemical castration is often used as a first-line therapy for advanced disease, but progression to the castration-resistant prostate cancer phase occurs with dependable frequency, largely through mutations to the androgen receptor (AR), aberrant AR signaling, and AR-independent mechanisms, among other causes. Semaphorin 3C (SEMA3C) is a secreted signaling protein that is essential for cardiac and neuronal development and has been shown to be regulated by the AR, to drive epithelial-to-mesenchymal transition and stem features in prostate cells, to activate receptor tyrosine kinases, and to promote cancer progression. Given that SEMA3C is linked to several key aspects of prostate cancer progression, we set out to explore SEMA3C inhibition by small molecules as a prospective cancer therapy. A homology-based SEMA3C protein structure was created, and its interaction with the neuropilin (NRP)-1 receptor was modeled to guide the development of the corresponding disrupting compounds. Experimental screening of 146 in silico‒identified molecules from the National Cancer Institute library led to the discovery of four promising candidates that effectively bind to SEMA3C, inhibit its association with NRP1, and attenuate prostate cancer growth. These findings provide proof of concept for the feasibility of inhibiting SEMA3C with small molecules as a therapeutic approach for prostate cancer.

Semaphorin 5A drives melanoma progression: role of Bcl-2, miR-204 and c-Myb

Background

Melanoma, the most aggressive form of skin cancer, is characterized by high rates of metastasis, drug resistance and mortality. Here we investigated the role of Semaphorin 5A (Sema5A) on the properties associated with melanoma progression and the factors involved in Sema5A regulation.

Methods

Western blotting, qRT-PCR, Chromatin immunoprecipitation (ChIP) assay, immunohistochemistry of melanoma patient specimens and xenograft tissues, in vitro Transwell assay for cell migration and invasion evaluation, in vitro capillary-like structure formation analysis.

Results

A significant correlation of Sema5A mRNA expression and melanoma progression was observed by analyzing GEO profile dataset. Endogenous Sema5A protein was detected in 95% of human melanoma cell lines tested, in 70% of metastatic specimens from patients affected by melanoma, and 16% of in situ melanoma specimens showed a focal positivity. We demonstrated that Sema5A regulates in vitro cell migration and invasion and the formation of vasculogenic structures. We also found an increase of Sema5A at both mRNA and protein level after forced expression of Bcl-2. By use of transcriptional and proteasome inhibitors, we showed that Bcl-2 increases the stability of Sema5A mRNA and protein. Moreover, by ChIP we demonstrated that Sema5A expression is under the control of the transcription factor c-Myb and that c-Myb recruitment on Sema5A promoter is increased after Bcl-2 overexpression. Finally, a concomitant decrease in the expression of Sema5A, Bcl-2 and c-Myb proteins was observed in melanoma cells after miR-204 overexpression.

Conclusion

Overall our data provide evidences supporting the role of Sema5A in melanoma progression and the involvement of Bcl-2, miR-204 and c-Myb in regulating its expression.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0933-x) contains supplementary material, which is available to authorized users.

Bidirectional regulation of bone formation by exogenous and osteosarcoma-derived Sema3A

Semaphorin 3A (Sema3A), a secreted member of the Semaphorin family, increases osteoblast differentiation, stimulates bone formation and enhances fracture healing. Here, we report a previously unknown role of Sema3A in the regulation of ectopic bone formation and osteolysis related to osteosarcoma. Human recombinant (exogenous) Sema3A promoted the expression of osteoblastic phenotype in a panel of human osteosarcoma cell lines and inhibited the ability of these cells to migrate and enhance osteoclastogenesis in vitro. In vivo, administration of exogenous Sema3A in mice after paratibial inoculation of KHOS cells increased bone volume in non-inoculated and tumour-bearing legs. In contrast, Sema3A overexpression reduced the ability of KHOS cells to cause ectopic bone formation in mice and to increase bone nodule formation by engaging DKK1/β-catenin signalling. Thus, Sema3A is of potential therapeutic efficacy in osteosarcoma. However, inhibition of bone formation associated with continuous exposure to Sema3A may limit its long-term usefulness as therapeutic agent.

A mechanism for semaphorin-induced apoptosis: DNA damage of endothelial and myogenic cells in primary cultures from skeletal muscle

One hallmark of cancer is its ability to recruit a vascular supply to support rapid growth. Suppression of angiogenesis holds potential as a second-line or adjuvant therapy to stunt cancer growth, progression, metastasis, and post-resection regeneration. To begin to test the hypothesis that semaphorin 3A and 3F together, will induce endothelial cell apoptosis by inducing DNA damage, mixed primary cultures isolated from normal adult mouse skeletal muscle were treated for 48 hr with Sema3A ± Sema3F (100ng/mL). Changes in surviving-cell density, DNA synthesis, DNA repair (gamma-Histone 2AX, γH2AX, an indirect measure for DNA damage), and apoptotic DNA fragmentation (TUNEL staining) were assayed in cultures of CD31+ endothelial and desmin+ muscle cells. Sema3F increased DNA damage-associated DNA repair in both cell types. Co-treatment with Sema3A+3F increased γH2AX staining ~25-fold over control levels, and further increased apoptosis compared to control and Sema3A alone. Results were negated by treatment with neutralizing anti-semaphorin antibodies and are interpreted as suggesting that Sema3A may sensitize endothelial but not muscle cells to Sema3F-induced DNA damage. These preliminary findings on a complex system of interacting cells may contribute to developing applications that could target angiogenic regulatory mechanisms for their therapeutic potential against cancer progression and metastasis.

Semaphorin 3A promotes osteogenic differentiation in human alveolar bone marrow mesenchymal stem cells

The aim of the present study was to investigate the role of Semaphorin 3A (Sema3A) in the osteogenic differentiation of human alveolar bone marrow mesenchymal stem cells (hABMMSCs). To investigate whether Sema3A affects hABMMSC proliferation and osteogenic differentiation, a stable Sema3A-overexpression cell line was generated by infection with the pAdCMV-SEMA3A-MCS-EGFP vector. Cell counting kit-8 and clone formation assays were performed to determine the proliferation ability of hABMMSCs, while cell osteogenic differentiation was assayed using Alizarin Red S staining. In addition, reverse transcription-quantitative polymerase chain reaction was employed to detect the mRNA expression level of osteogenesis-associated genes, Runt-related transcription factor 2 (Runx2), osteopontin (Opn) and osteocalcin (Ocn), during the osteogenic differentiation. The results revealed that, compared with the normal control group, the cell morphology of the infected cells was stable and no significant alterations were observed. Overexpression of Sema3A in hABMMSCs significantly increased the cell proliferation ability compared with the control group. Furthermore, the Alizarin Red S staining assay results indicated that the ossification process of hABMMSCs overexpressing Sema3A was evidently faster in comparison with that of the control group cells. Overexpression of Sema3A by pAdCMV-SEMA3A-MCS-EGFP infection also significantly increased the mRNA expression levels of the osteogenic marker genes Runx2, Opn and Ocn. In conclusion, Sema3A was observed to be a key positive regulator in hABMMSC osteogenic differentiation.

Sema3A drastically suppresses tumor growth in oral cancer Xenograft model of mice

Background

Multiple studies suggest anti-angiogenesis to be a promising and rational option in cancer treatment. Interestingly, the axonal sprouting inhibitor semaphorin 3A (Sema3A), a potent suppressor of tumor angiogenesis in various cancer models, is lowly expressed in human oral cancer. Thus, we hypothesized that overexpression of Sema3A in human oral cancer cells may have potential therapeutic effects.

Methods

The LentiSema3A-EGFP was first constructed and transduced to the tongue squamous cell carcinoma cell line SSC-9. Angiogenesis assay was performed with endothelial cell tube formation assay and chorioallantoic membrane (CAM) assay. Tumor xenografts model was used to evaluate the effect of Sema3a on the tumor growth. Finally, western blot was performed to study the mechanisms of inhibiting angiogenesis by Sema3A.

Results

In vitro and in vivo approaches revealed that Sema3A significantly inhibited tube formation of endothelial cells and reduced angiogenesis in CAM assay. In addition, overexpression of Sema3A in the tongue squamous cell carcinoma cell line SSC-9 resulted in significantly reduced angiogenesis and drastically suppressed tumor growth in mice. Mechanistically, Sema3A inhibited the phosphorylation of VEGFR2, as well as Src and FAK, downstream of the VEGF/VEGFR2 pathway.

Conclusion

Our results demonstrated that overexpression of Sema3A in oral cancer cells drastically suppressed tumor growth by inhibiting angiogenesis. Our findings provide a basis for the development of novel therapeutics in the management of oral cancer.

Sema3A promotes the resolution of cardiac inflammation after myocardial infarction

Optimal healing after myocardial infarction requires not only the induction of inflammation, but also its timely resolution. In patients, 30 days post myocardial infarction, circulating monocytes have increased expression of Semaphorin3A (Sema3A) as compared to directly after admission. This increased expression coincides with increased expression of Cx3CR1—a marker of non-classical monocytes that are important for immune resolution hence proper wound healing. In mice, the expression of Sema3A also increases in response to myocardial ischemia being expressed by infiltrating leukocytes. Comparing Sema3A heterozygote (HZ) and wild type (WT) mice post myocardial infarction, revealed increased presence of leukocytes in the cardiac tissues of HZ mice as compared to WT, with no differences in capillary density, collagen deposition, cardiomyocyte surface area, chemokine—or adhesion molecules expression. Whilst infarct sizes were similar 14 days after myocardial infarction in both genotypes, Sema3A HZ mice had thinner infarcts and reduced cardiac function as compared to their WT littermates. In vitro experiments were conducted to study the role of Sema3A in inflammation and resolution of inflammation as a potential explanation for the differences in leukocyte recruitment and cardiac function observed in our in vivo experiments. Here, recombinant Sema3A protein was able to affect the pro-inflammatory state of cultured bone marrow derived macrophages. First, the pro-inflammatory state was altered by the induced apoptosis of classical macrophages in the presence of Sema3A. Second, Sema3A promoted the polarization of classical macrophages to resolution-phase macrophages and enhanced their efferocytotic ability, findings that were reflected in the infarcted cardiac tissue of the Sema3A HZ mice. Finally, we demonstrated that besides promoting resolution of inflammation, Sema3A was also able to retard the migration of monocytes to the myocardium. Collectively our data demonstrate that Sema3A reduces cardiac inflammation and improves cardiac function after myocardial infarction by promoting the resolution of inflammation.

Axon guidance molecule semaphorin3A is a novel tumor suppressor in head and neck squamous cell carcinoma

Semaphorin3A (SEMA3A), an axon guidance molecule in the nervous system, plays an inhibitory role in oncogenesis. Here, we investigated the expression pattern and biological roles of SEMA3A in head and neck squamous cell carcinoma (HNSCC) by gain-of-function assays using adenovirus transfection and recombinant human SEMA3A protein. In addition, we explored the therapeutic efficacy of SEMA3A against HNSCC in vivo. We found that lower expression of SEMA3A correlated with shorter overall survival and had independent prognostic importance in patients with HNSCC. Both genetic and recombinant SEMA3A protein inhibited cell proliferation and colony formation and induced apoptosis, accompanied by decreased cyclin E, cyclin D, CDK2, CDK4 and CDK6 and increased P21, P27, activated caspase-5 and caspase-7. Moreover, over-expression of SEMA3A suppressed migration, invasion and epithelial-to-mesenchymal transition due in part to the inhibition of NF-κB and SNAI2 in HNSCC cell lines. Furthermore, intratumoral SEMA3A delivery significantly stagnated tumor growth in a xenograft model. Taken together, our results indicate that SEMA3A serves as a tumor suppressor during HNSCC tumorigenesis and a new target for the treatment of HNSCC.

Semaphorin 3A Increases FAK Phosphorylation at Focal Adhesions to Modulate MDA-MB-231 Cell Migration and Spreading on Different Substratum Concentrations

Interactions between integrin-mediated adhesions and the extracellular matrix (ECM) are important regulators of cell migration and spreading. However, mechanisms by which extracellular ligands regulate cell migration and spreading in response to changes in substratum concentration are not well understood. Semaphorin 3A (Sema3A) has been shown to inhibit cell motility and alter integrin signaling in various cell types. We propose that Sema3A alters focal adhesions to modulate breast carcinoma cell migration and spreading on substrata coated with different concentrations of ECM. We demonstrate that Sema3A inhibits MDA-MB-231 cell migration and spreading on substrata coated with high concentrations of collagen and fibronectin but enhances migration and spreading at lower concentrations of collagen and fibronectin. Sema3A increases focal adhesion kinase phosphorylation at tyrosine 397 (pFAK³⁹⁷) at focal adhesions on all substratum concentrations of collagen and fibronectin but decreased pFAK³⁹⁷ levels on laminin. Rho-associated protein kinase (ROCK) inhibition blocks the Sema3A-mediated effects on cell migration, spreading, and pFAK³⁹⁷ at focal adhesions when cultured on all concentrations of collagen. These results suggest that Sema3A shifts the optimal level of cell-matrix adhesions to a nonoptimal ECM coating concentration, in particular collagen, to yield maximal cell migration and spreading that may be mediated through a ROCK-dependent mechanism.

The role of the semaphorins in cancer

The semaphorins were initially characterized as axon guidance factors, but have subsequently been implicated also in the regulation of immune responses, angiogenesis, organ formation, and a variety of additional physiological and developmental functions. The semaphorin family contains more then 20 genes divided into 7 subfamilies, all of which contain the signature sema domain. The semaphorins transduce signals by binding to receptors belonging to the neuropilin or plexin families. Additional receptors which form complexes with these primary semaphorin receptors are also frequently involved in semaphorin signaling. Recent evidence suggests that semaphorins also fulfill important roles in the etiology of multiple forms of cancer. Some semaphorins have been found to function as bona-fide tumor suppressors and to inhibit tumor progression by various mechanisms while other semaphorins function as inducers and promoters of tumor progression.

Plexin A1 signaling confers malignant phenotypes in lung cancer cells

Aberrant changes to several signaling pathways because of genetic mutations or increased cytokine production are critical for tumor cells to become malignant. Semaphorin 3A (SEMA3A) acts as a bivalent factor that suppresses or promotes tumor development in different pathological backgrounds. Previously, we showed that SEMA3A positively regulated the proliferative and glycolytic activities of mouse-derived Lewis lung carcinoma (LLC) cells. Plexins A1-A4 (PLXNA1-PLXNA4) are SEMA3A receptors; however, it is not known which subtype is critical for oncogenic SEMA3A signaling. We used LLC cells to investigate the role of PLXNA1 in oncogenic SEMA3A signaling. Using short hairpin RNA-mediated knockdown, we investigated the effects of constitutive inhibition of Plxna1 on cell proliferation, metabolic dependency, and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) sensitivity. We found that Plxna1 knockdown did not affect apoptosis but resulted in decreased cell proliferation and reductions in mRNA expression levels of proliferation-marker genes, such as Ccnd1, Pcna, and Myc. In addition, we found decreased mRNA expression levels of glycolysis-associated genes, such as Pkm2 and Ldha, and decreased lactate production. In contrast, we found no changes in the mRNA expression levels of oxidative phosphorylation-associated genes, such as Cycs, Cox5a, and Atp5g1. We found that Plxna1 knockdown conferred resistance to glucose starvation but increased cytotoxicity to oligomycin. Plxna1 or Sema3a knockdown caused an increased sensitivity to the EGFR-TKIs gefitinib and erlotinib, in Lewis lung carcinoma (LLC) cells. These findings demonstrate that PLXNA1 mediates the acquisition of malignant phenotypes induced by autocrine SEMA3A signaling.

Curcumin: A new candidate for melanoma therapy?

Melanoma remains among the most lethal cancers and, in spite of great attempts that have been made to increase the life span of patients with metastatic disease, durable and complete remissions are rare. Plants and plant extracts have long been used to treat a variety of human conditions; however, in many cases, effective doses of herbal remedies are associated with serious adverse effects. Curcumin is a natural polyphenol that shows a variety of pharmacological activities including anti-cancer effects, and only minimal adverse effects have been reported for this phytochemical. The anti-cancer effects of curcumin are the result of its anti-angiogenic, pro-apoptotic and immunomodulatory properties. At the molecular and cellular level, curcumin can blunt epithelial-to-mesenchymal transition and affect many targets that are involved in melanoma initiation and progression (e.g., BCl2, MAPKS, p21 and some microRNAs). However, curcumin has a low oral bioavailability that may limit its maximal benefits. The emergence of tailored formulations of curcumin and new delivery systems such as nanoparticles, liposomes, micelles and phospholipid complexes has led to the enhancement of curcumin bioavailability. Although in vitro and in vivo studies have demonstrated that curcumin and its analogues can be used as novel therapeutic agents in melanoma, curcumin has not yet been tested against melanoma in clinical practice. In this review, we summarized reported anti-melanoma effects of curcumin as well as studies on new curcumin formulations and delivery systems that show increased bioavailability. Such tailored delivery systems could pave the way for enhancement of the anti-melanoma effects of curcumin.

Tumor cell-derived secretory factor downregulates Semaphorin-3a in osteoblasts by activating mammalian target of rapamycin pathway

We found that conditioned medium derived from Lewis Lung Carcinoma cells down-regulated Semaphorin3a (Sema3a) mRNA expression and increased the activity of mammalian target of rapamycin complex 1 (mTORC1) in osteoblast-like MC3T3-E1 cells. Furthermore, mTORC1 inhibition with rapamycin counteracted the effect of conditioned media on Sema3a mRNA expression. These results suggest that tumor cells decrease Sema3a mRNA expression in osteoblast in an mTORC1-dependent manner.

WITHDRAWN: Lentiviral Mediated Overexpression of Sema3A in Oral Cancer Cells Decreases Tumor Growth by Inhibiting Angiogenesis

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Tumor Suppressor Function of the SEMA3B Gene in Human Lung and Renal Cancers

The SEMA3B gene is located in the 3p21.3 LUCA region, which is frequently affected in different types of cancer. The objective of our study was to expand our knowledge of the SEMA3B gene as a tumor suppressor and the mechanisms of its inactivation. In this study, several experimental approaches were used: tumor growth analyses and apoptosis assays in vitro and in SCID mice, expression and methylation assays and other. With the use of the small cell lung cancer cell line U2020 we confirmed the function of SEMA3B as a tumor suppressor, and showed that the suppression can be realized through the induction of apoptosis and, possibly, associated with the inhibition of angiogenesis. In addition, for the first time, high methylation frequencies have been observed in both intronic (32-39%) and promoter (44-52%) CpG-islands in 38 non-small cell lung carcinomas, including 16 squamous cell carcinomas (SCC) and 22 adenocarcinomas (ADC), and in 83 clear cell renal cell carcinomas (ccRCC). Correlations between the methylation frequencies of the promoter and the intronic CpG-islands of SEMA3B with tumor stage and grade have been revealed for SCC, ADC and ccRCC. The association between the decrease of the SEMA3B mRNA level and hypermethylation of the promoter and the intronic CpG-islands has been estimated in renal primary tumors (P < 0.01). Using qPCR, we observed on the average 10- and 14-fold decrease of the SEMA3B mRNA level in SCC and ADC, respectively, and a 4-fold decrease in ccRCC. The frequency of this effect was high in both lung (92-95%) and renal (84%) tumor samples. Moreover, we showed a clear difference (P < 0.05) of the SEMA3B relative mRNA levels in ADC with and without lymph node metastases. We conclude that aberrant expression and methylation of SEMA3B could be suggested as markers of lung and renal cancer progression.

The potential of class 3 semaphorins as both targets and therapeutics in cancer

INTRODUCTION

Semaphorins have been originally identified as a family of evolutionary conserved soluble or membrane-associated proteins involved in diverse developmental phenomena. This family of proteins profoundly influences numerous pathophysiological processes, including organogenesis, cardiovascular development and immune response. Apart from steering the neural networking process, these are implicated in a broad range of biological operations including regulation of tumor progression and angiogenesis.

AREAS COVERED

Members of class 3 semaphorin family are known to modulate various cellular processes involved in malignant transformation. Some of the family members trigger diverse signaling processes involved in tumor progression and angiogenesis by binding with plexin and neuropilin. A better understanding of the various signaling mechanisms by which semaphorins modulate tumor progression and angiogenesis may serve as crucial tool in crafting new semaphorin-based anticancer therapy. These include treatment with recombinant tumor suppressive semaphorins or inhibition of tumor-promoting semaphorins by their specific siRNAs, small-molecule inhibitors or specific receptors using neutralizing antibodies or blocking peptides that might serve as novel strategies for effective management of cancers.

EXPERT OPINION

This review focuses on all the possible avenues to explore various members of class 3 semaphorin family to serve as therapeutics for combating cancer.

Trefoil factor 3 promotes metastatic seeding and predicts poor survival outcome of patients with mammary carcinoma

Introduction

Recurrence or early metastasis remains the predominant cause of mortality in patients with estrogen receptor positive (ER+) mammary carcinoma (MC). However, the molecular mechanisms underlying the initial progression of ER+ MC to metastasis remains poorly understood. Trefoil factor 3 (TFF3) is an estrogen-responsive oncogene in MC. Herein, we provide evidence for a functional role of TFF3 in metastatic progression of ER+ MC.

Methods

The association of TFF3 expression with clinicopathological parameters and survival outcome in a cohort of MC patients was assessed by immunohistochemistry. The expression of TFF3 in MCF7 and T47D cells was modulated by forced expression or siRNA-mediated depletion of TFF3. mRNA and protein levels were determined using qPCR and western blot. The functional effect of modulation of TFF3 expression in MC cells was determined in vitro and in vivo. Mechanistic analyses were performed using reporter constructs, modulation of signal transducer and activator of transcription 3 (STAT3) expression, and pharmacological inhibitors against c-SRC and STAT3 activity.

Results

TFF3 protein expression was positively associated with larger tumour size, lymph node metastasis, higher stage, and poor survival outcome. Forced expression of TFF3 in ER+ MC cells stimulated colony scattering, cell adhesion to a Collagen I-coated matrix, colony formation on a Collagen I- or Matrigel-coated matrix, endothelial cell adhesion, and transmigration through an endothelial cell barrier. In vivo, forced expression of TFF3 in MCF7 cells stimulated the formation of metastatic nodules in animal lungs. TFF3 regulation of the mRNA levels of epithelial, mesenchymal, and metastatic-related genes in ER+ MC cells were consistent with the altered cell behaviour. Forced expression of TFF3 in ER+ MC cells stimulated phosphorylation of c-SRC that subsequently increased STAT3 activity, which lead to the downregulation of E-cadherin. siRNA-mediated depletion of TFF3 reduced the invasiveness of ER+ MC cells.

Conclusions

TFF3 expression predicts metastasis and poor survival outcome of patients with MC and functionally stimulates cellular invasion and metastasis of ER+ MC cells. Adjuvant functional inhibition of TFF3 may therefore be considered to ameliorate outcome of ER+ MC patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0429-3) contains supplementary material, which is available to authorized users.

The emerging role of class-3 semaphorins and their neuropilin receptors in oncology

The semaphorins, discovered over 20 years ago, are a large family of secreted or transmembrane and glycophosphatidylinositol -anchored proteins initially identified as axon guidance molecules crucial for the development of the nervous system. It has now been established that they also play important roles in organ development and function, especially involving the immune, respiratory, and cardiovascular systems, and in pathological disorders, including cancer. During tumor progression, semaphorins can have both pro- and anti-tumor functions, and this has created complexities in our understanding of these systems. Semaphorins may affect tumor growth and metastases by directly targeting tumor cells, as well as indirectly by interacting with and influencing cells from the micro-environment and vasculature. Mechanistically, semaphorins, through binding to their receptors, neuropilins and plexins, affect pathways involved in cell adhesion, migration, invasion, proliferation, and survival. Importantly, neuropilins also act as co-receptors for several growth factors and enhance their signaling activities, while class 3 semaphorins may interfere with this. In this review, we focus on the secreted class 3 semaphorins and their neuropilin co-receptors in cancer, including aspects of their signaling that may be clinically relevant.

Modeling time-dependent transcription effects of HER2 oncogene and discovery of a role for E2F2 in breast cancer cell-matrix adhesion

MOTIVATION

Oncogenes are known drivers of cancer phenotypes and targets of molecular therapies; however, the complex and diverse signaling mechanisms regulated by oncogenes and potential routes to targeted therapy resistance remain to be fully understood. To this end, we present an approach to infer regulatory mechanisms downstream of the HER2 driver oncogene in SUM-225 metastatic breast cancer cells from dynamic gene expression patterns using a succession of analytical techniques, including a novel MP grammars method to mathematically model putative regulatory interactions among sets of clustered genes.

RESULTS

Our method highlighted regulatory interactions previously identified in the cell line and a novel finding that the HER2 oncogene, as opposed to the proto-oncogene, upregulates expression of the E2F2 transcription factor. By targeted gene knockdown we show the significance of this, demonstrating that cancer cell-matrix adhesion and outgrowth were markedly inhibited when E2F2 levels were reduced. Thus, validating in this context that upregulation of E2F2 represents a key intermediate event in a HER2 oncogene-directed gene expression-based signaling circuit. This work demonstrates how predictive modeling of longitudinal gene expression data combined with multiple systems-level analyses can be used to accurately predict downstream signaling pathways. Here, our integrated method was applied to reveal insights as to how the HER2 oncogene drives a specific cancer cell phenotype, but it is adaptable to investigate other oncogenes and model systems.

AVAILABILITY AND IMPLEMENTATION

Accessibility of various tools is listed in methods; the Log-Gain Stoichiometric Stepwise algorithm is accessible at http://www.cbmc.it/software/Software.php.

Decreased expression of SEMA3A is associated with poor prognosis in gastric carcinoma

BACKGROUND/PURPOSE

SEMA3A (semaphorin-3A), is a secreted protein that belongs to the semaphorin family and can function as both a chemoattractive agent or a chemorepulsive agent. SEMA3A has been shown to be a tumor suppressor in various cancers. This study investigated the expression of SEMA3A in gastric cancer and its prognostic value for gastric cancer patients.

METHODS

We examined the expression of SEMA3A in paired cancerous and matched adjacent noncancerous gastric mucosa tissues by real-time quantitative RT-PCR (qRT-PCR) and western blotting. In vitro, we evaluate the effects of SEMA3A on gastric cancer cell proliferation and migration by MTT, transwell and wound-healing assays. Furthermore, we analyzed SEMA3A expression in 128 patients who underwent resection procedures using immunohistochemistry. The relationships between the SEMA3A expression levels, the clinicopathological factors, and patient survival were investigated.

RESULTS

Our results revealed decreased SEMA3A mRNA (P = 0.0037) and protein (P = 0.033) expression in tumor tissue samples compared with matched adjacent non-tumorous tissue samples. Overexpression of SEMA3A inhibits gastric cancer cell proliferation and migration in vitro. Immunohistochemical staining data showed that SEMA3A expression was significantly decreased in 54.68% of gastric cancer cases. In addition, the chi-square test revealed that low SEMA3A expression was significantly correlated with poor differentiation (P = 0.015), Vascular invasion (P = 0.001), depth of invasion (P < 0.001), lymph node metastasis (P = 0.029), distant metastasis (P = 0.002) and advanced TNM stage (P = 0.003). SEMA3A expression was positively correlated with clinical TNM stage, that suggested the more advanced clinical TNM stage corresponding to the lower expression level of SEMA3A (rs = -0.322, P < 0.001) by Spearman rank correlation analysis. Kaplan-Meier survival analysis demonstrated that low expression of SEMA3A was significantly correlated with a poor prognosis for gastric cancer patients (P < 0.001). The multivariate analysis revealed that SEMA3A expression was an independent prognostic factor of the overall survival rate of patients with gastric cancer.

CONCLUSION

SEMA3A expression decreased significantly as gastric cancer progressed and metastasized, suggesting that SEMA3A might serve as a candidate tumor suppressor and a potential prognostic biomarker in gastric carcinogenesis.

Emerging roles of Semaphorins in the regulation of epithelial and endothelial junctions

Tissue barriers maintain homeostasis, protect underlying tissues, are remodeled during organogenesis and injury and limit aberrant proliferation and dissemination. In this context, endothelial and epithelial intercellular junctions are the primary targets of various cues. This cellular adaptation requires plasticity and dynamics of adhesion molecules and the associated cytoskeleton, as well as the adhesive-linked signaling platforms. It is therefore not surprising that the guidance molecules from the Semaphorin family arise as novel modifiers of epithelia and endothelia in development and diseases. This review will focus on the actions of Semaphorins, and their cognate receptors, Plexins and Neuropilins, on epithelial and endothelial barrier properties.