Neuropilin-2 expression promotes TGF-β1-mediated epithelial to mesenchymal transition in colorectal cancer cells

The impact of the embryonic DNA methylation program on CTCF-mediated genome regulation

During mammalian embryogenesis, both the 5-cytosine DNA methylation (5meC) landscape and three dimensional (3D) chromatin architecture are profoundly remodeled during a process known as 'epigenetic reprogramming.' An understudied aspect of epigenetic reprogramming is how the 5meC flux, per se, affects the 3D genome. This is pertinent given the 5meC-sensitivity of DNA binding for a key regulator of chromosome folding: CTCF. We profiled the CTCF binding landscape using a mouse embryonic stem cell (ESC) differentiation protocol that models embryonic 5meC dynamics. Mouse ESCs lacking DNA methylation machinery are able to exit naive pluripotency, thus allowing for dissection of subtle effects of CTCF on gene expression. We performed CTCF HiChIP in both wild-type and mutant conditions to assess gained CTCF-CTCF contacts in the absence of 5meC. We performed H3K27ac HiChIP to determine the impact that ectopic CTCF binding has on cis-regulatory contacts. Using 5meC epigenome editing, we demonstrated that the methyl-mark is able to impair CTCF binding at select loci. Finally, a detailed dissection of the imprinted Zdbf2 locus showed how 5meC-antagonism of CTCF allows for proper gene regulation during differentiation. This work provides a comprehensive overview of how 5meC impacts the 3D genome in a relevant model for early embryonic events.

Role of Native Probiotic Lactobacillus Species via TGF-β Signaling Pathway Modulation in CRC

Background

Colon microbiome composition in colorectal cancer (CRC) patients undergoes remarkable changes. The present study was designed to assess the impact of Lactobacillus mixture on the regulating the CRC by influencing the transforming growth factor beta (TGF-β) signaling pathway in both in vitro (HT-29 cancer cells) and in vivo (BALB/c mice) models.

Methods

In this study, the antiproliferative effect of a native potential probiotic Lactobacillus mixture on HT-29 cancer cells was evaluated using the MTT assay method. Also, qRT-PCR was performed to assess the RNA expression level of genes associated with the TGF-β signaling pathway at three levels: receptor, regulatory, and inhibitory SMADs. Finally, the in vivo assays were investigated by three groups of mice: a naive group (PBS), a disease group (azoxymethane [AOM]/ dextran sulfate sodium [DSS] + PBS), and a treatment group (AOM/DSS + Lactobacillus mixture in PBS).

Results

The MTT results showed a significant decrease in proliferation of HT-29 cancer cells after 120 h of treatment. Furthermore, qRT-PCR demonstrated the downregulation of the smad2/3 gene expression in HT-29-treated cells and also reduction in the level of smad4 gene expression. In addition, in the mouse model, the tgf-βR1 gene was downregulated in the group treated with AOM/DSS/Lactobacillus, but not the AOM/DSS group. A downregulation of smad4 gene expression was also observed in in vivo models.

Conclusion

The obtained results suggest that our novel probiotic Lactobacillus mixture could have a positive impact on the inhibition of the CRC progression by downregulating the TGF-β signaling pathway.

Neuropilin2 in Mesenchymal Stromal Cells as a Potential Novel Therapeutic Target in Myelofibrosis

Bone marrow fibrosis in myeloproliferative neoplasm (MPN), myelodysplastic syndromes (MDS), MPN/MDS overlap syndromes and acute myeloid leukemia (AML) is associated with poor prognosis and early treatment failure. Myelofibrosis (MF) is accompanied by reprogramming of multipotent bone marrow mesenchymal stromal cells (MSC) into osteoid and fiber-producing stromal cells. We demonstrate NRP2 and osteolineage marker NCAM1 (neural cell adhesion molecule 1) expression within the endosteal niche in normal bone marrow and aberrantly in MPN, MDS MPN/MDS overlap syndromes and AML (n = 99), as assessed by immunohistochemistry. Increased and diffuse expression in mesenchymal stromal cells and osteoblasts correlates with high MF grade in MPN (p < 0.05 for NRP2 and NCAM1). Single cell RNA sequencing (scRNAseq) re-analysis demonstrated NRP2 expression in endothelial cells and partial co-expression of NRP2 and NCAM1 in normal MSC and osteoblasts. Potential ligands included transforming growth factor β1 (TGFB1) from osteoblasts and megakaryocytes. Murine ThPO and JAK2V617F myelofibrosis models showed co-expression of Nrp2 and Ncam1 in osteolineage cells, while fibrosis-promoting MSC only express Nrp2. In vitro experiments with MC3T3-E1 pre-osteoblasts and analysis of Nrp2-/- mouse femurs suggest that Nrp2 is functionally involved in osteogenesis. In summary, NRP2 represents a potential novel druggable target in patients with myelofibrosis.

Recent advances of mechanosensitive genes in vascular endothelial cells for the formation and treatment of atherosclerosis

Atherosclerotic cardiovascular disease and its complications are a high-incidence disease worldwide. Numerous studies have shown that blood flow shear has a huge impact on the function of vascular endothelial cells, and it plays an important role in gene regulation of pro-inflammatory, pro-thrombotic, pro-oxidative stress, and cell permeability. Many important endothelial cell mechanosensitive genes have been discovered, including KLK10, CCN gene family, NRP2, YAP, TAZ, HIF-1α, NF-κB, FOS, JUN, TFEB, KLF2/KLF4, NRF2, and ID1. Some of them have been intensively studied, whereas the relevant regulatory mechanism of other genes remains unclear. Focusing on these mechanosensitive genes will provide new strategies for therapeutic intervention in atherosclerotic vascular disease. Thus, this article reviews the mechanosensitive genes affecting vascular endothelial cells, including classical pathways and some newly screened genes, and summarizes the latest research progress on their roles in the pathogenesis of atherosclerosis to reveal effective therapeutic targets of drugs and provide new insights for anti-atherosclerosis.

Orchestrating Resilience: How Neuropilin-2 and Macrophages Contribute to Cardiothoracic Disease

Immunity has evolved to balance the destructive nature of inflammation with wound healing to overcome trauma, infection, environmental insults, and rogue malignant cells. The inflammatory response is marked by overlapping phases of initiation, resolution, and post-resolution remodeling. However, the disruption of these events can lead to prolonged tissue damage and organ dysfunction, resulting long-term disease states. Macrophages are the archetypic phagocytes present within all tissues and are important contributors to these processes. Pleiotropic and highly plastic in their responses, macrophages support tissue homeostasis, repair, and regeneration, all while balancing immunologic self-tolerance with the clearance of noxious stimuli, pathogens, and malignant threats. Neuropilin-2 (Nrp2), a promiscuous co-receptor for growth factors, semaphorins, and integrins, has increasingly been recognized for its unique role in tissue homeostasis and immune regulation. Notably, recent studies have begun to elucidate the role of Nrp2 in both non-hematopoietic cells and macrophages with cardiothoracic disease. Herein, we describe the unique role of Nrp2 in diseases of the heart and lung, with an emphasis on Nrp2 in macrophages, and explore the potential to target Nrp2 as a therapeutic intervention.

Semaphorin 3C exacerbates liver fibrosis

BACKGROUND AND AIMS

Chronic liver disease is a growing epidemic, leading to fibrosis and cirrhosis. TGF-β is the pivotal profibrogenic cytokine that activates HSC, yet other molecules can modulate TGF-β signaling during liver fibrosis. Expression of the axon guidance molecules semaphorins (SEMAs), which signal through plexins and neuropilins (NRPs), have been associated with liver fibrosis in HBV-induced chronic hepatitis. This study aims at determining their function in the regulation of HSCs.

APPROACH AND RESULTS

We analyzed publicly available patient databases and liver biopsies. We used transgenic mice, in which genes are deleted only in activated HSCs to perform ex vivo analysis and animal models. SEMA3C is the most enriched member of the semaphorin family in liver samples from patients with cirrhosis. Higher expression of SEMA3C in patients with NASH, alcoholic hepatitis, or HBV-induced hepatitis discriminates those with a more profibrotic transcriptomic profile. SEMA3C expression is also elevated in different mouse models of liver fibrosis and in isolated HSCs on activation. In keeping with this, deletion of SEMA3C in activated HSCs reduces myofibroblast marker expression. Conversely, SEMA3C overexpression exacerbates TGF-β-mediated myofibroblast activation, as shown by increased SMAD2 phosphorylation and target gene expression. Among SEMA3C receptors, only NRP2 expression is maintained on activation of isolated HSCs. Interestingly, lack of NRP2 in those cells reduces myofibroblast marker expression. Finally, deletion of either SEMA3C or NRP2, specifically in activated HSCs, reduces liver fibrosis in mice.

CONCLUSION

SEMA3C is a novel marker for activated HSCs that plays a fundamental role in the acquisition of the myofibroblastic phenotype and liver fibrosis.

Neuropilins as potential biomarkers in hepatocellular carcinoma: a systematic review of basic and clinical implications

Hepatocellular carcinoma (HCC) is one of the most common and deadly cancers worldwide and is characterized by complex molecular carcinogenesis. Neuropilins (NRPs) NRP1 and NRP2 are the receptors of multiple proteins involved in key signaling pathways associated with tumor progression. We aimed to systematically review all the available findings on their role in HCC. We searched the Scopus, Web of Science (WOS), PubMed, Cochrane and Embase databases for articles evaluating NRPs in preclinical or clinical HCC models. This study was registered in PROSPERO (CRD42022349774) and include 49 studies. Multiple cellular and molecular processes have been associated with one or both NRPs, indicating that they are potential diagnostic and prognostic biomarkers in HCC patients. Mainly NRP1 has been shown to promote tumor cell survival and progression by modulating several signaling pathways. NRPs mainly regulate angiogenesis, invasion and migration and have shown to induce invasion and metastasis. They also regulate the immune response and tumor microenvironment, showing a crucial interplay with the hypoxia response and microRNAs in HCC. Altogether, NRP1 and NRP2 are potential biomarkers and therapeutic targets, providing novel insight into the clinical landscape of HCC patients.

Role of Neuropilin-2-mediated signaling axis in cancer progression and therapy resistance

Neuropilins (NRPs) are transmembrane proteins involved in vascular and nervous system development by regulating angiogenesis and axon guidance cues. Several published reports have established their role in tumorigenesis. NRPs are detectable in tumor cells of several cancer types and participate in cancer progression. NRP2 is also expressed in endothelial and immune cells in the tumor microenvironment and promotes functions such as lymphangiogenesis and immune suppression important for cancer progression. In this review, we have taken a comprehensive approach to discussing various aspects of NRP2-signaling in cancer, including its regulation, functional significance in cancer progression, and how we could utilize our current knowledge to advance the studies and target NRP2 to develop effective cancer therapies.

Transforming growth factor β latency: A mechanism of cytokine storage and signalling regulation in liver homeostasis and disease

Transforming growth factor-β (TGF-β) is a potent effector in the liver, which is involved in a plethora of processes initiated upon liver injury. TGF-β affects parenchymal, non-parenchymal, and inflammatory cells in a highly context-dependent manner. Its bioavailability is critical for a fast response to various insults. In the liver – and probably in other organs – this is made possible by the deposition of a large portion of TGF-β in the extracellular matrix as an inactivated precursor form termed latent TGF-β (L-TGF-β). Several matrisomal proteins participate in matrix deposition, latent complex stabilisation, and activation of L-TGF-β. Extracellular matrix protein 1 (ECM1) was recently identified as a critical factor in maintaining the latency of deposited L-TGF-β in the healthy liver. Indeed, its depletion causes spontaneous TGF-β signalling activation with deleterious effects on liver architecture and function. This review article presents the current knowledge on intracellular L-TGF-β complex formation, secretion, matrix deposition, and activation and describes the proteins and processes involved. Further, we emphasise the therapeutic potential of toning down L-TGF-β activation in liver fibrosis and liver cancer.

Loss of Neuropilin-2 in Murine Mesenchymal-like Colon Cancer Organoids Causes Mesenchymal-to-Epithelial Transition and an Acquired Dependency on Insulin-Receptor Signaling and Autophagy

Simple Summary

Many cancer types are reported to have high lymphangiogenic receptor Neuropilin-2 (Nrp2) expression, including colorectal cancer (CRC). Nrp2 is shown to be associated with tumor progression in vivo and poor prognosis in CRC patients. Although the role of Nrp2 is well established in lymphangiogenesis, the tumor cell-intrinsic role of Nrp2 remains elusive. Here, we employed murine CRC tumor-derived mesenchymal-like organoids to induce Nrp2 depletion. We demonstrate that Nrp2 deletion in CRC organoids results in a drastically altered phenotype that is characterized by mesenchymal-to-epithelial transition (MET), and an acquired dependency on IR signaling and autophagy. This phenotype is preserved in subcutaneous tumors generated by CRC organoids. We conclude that there is a complex interaction between Nrp2 and alternative pro-survival mechanisms in aggressive CRC, which could be therapeutically exploited.

Abstract

Neuropilin-2 (Nrp2), an important regulator of lymphangiogenesis and lymphatic metastasis, has been associated with progression in colorectal cancer (CRC). However, the tumor cell-intrinsic role of Nrp2 in cancer progression is incompletely understood. To address this question, we employed CRISPR-Cas9 technology to generate Nrp2-knockout organoids derived from murine CRC tumors with a mesenchymal phenotype. Transcriptome profiling and tumor tissue analysis showed that Nrp2 loss resulted in mesenchymal-to-epithelial transition (MET), which was accompanied with restored polarity and tight junction stabilization. Signaling pathway analysis revealed that Nrp2-knockout organoids acquire de novo dependency on insulin receptor (IR) signaling and autophagy as alternative survival mechanisms. Combined inhibition of IR signaling and autophagy prevented the stabilization of cell-cell junctions, reduced metabolic activity, and caused profound cell death in Nrp2-knockout organoids. Collectively, the data demonstrate a key role for Nrp2 in maintaining the aggressive phenotype and survival of tumor-derived CRC organoids. The identified connection between Nrp2, insulin receptor signaling and autophagy may guide the development of novel combination-treatment strategies for aggressive CRC.

NRP2 promotes atherosclerosis by upregulating PARP1 expression and enhancing low shear stress-induced endothelial cell apoptosis

Atherosclerosis-related cardiovascular diseases are leading causes of mortality worldwide, characterized by the development of endothelial cell dysfunction, increased oxidized low-density lipoprotein uptake by macrophages, and the ensuing formation of atherosclerotic plaque. Local blood flow patterns cause uneven atherosclerotic lesion distribution, and endothelial dysfunction caused by disturbed flow is an early step in the development of atherosclerosis. The present research aims to elucidate the mechanism underlying the regulation of Neuropilin 2 (NRP2) under low shear stress (LSS) in the atheroprone phenotype of endothelial cells. We observed that NRP2 expression was significantly upregulated in LSS-stimulated human umbilical vein endothelial cells (HUVECs) and in mouse aortic endothelial cells. Knockdown of NRP2 in HUVECs significantly ameliorated cell apoptosis induced by LSS. Conversely, overexpression of NRP2 had the opposite effect on HUVEC apoptosis. Animal experiments suggest that NRP2 knockdown markedly mitigated the development of atherosclerosis in Apoe^-/- mice. Mechanistically, NRP2 knockdown and overexpression regulated PARP1 protein expression in the condition of LSS, which in turn affected the expression of apoptosis-related genes. Moreover, the upstream transcription factor GATA2 was found to regulate NRP2 expression in the progression of atherosclerosis. These findings suggest that NRP2 plays an essential proatherosclerotic role through the regulation of cell apoptosis, and the results reveal that NRP2 is a promising therapeutic target for the treatment of atherosclerotic disorders.

The Role of Neuropilin-2 in the Epithelial to Mesenchymal Transition of Colorectal Cancer: A Systematic Review

Neuropilin-2 (NRP-2) expression has been found in various investigations on the expression and function of NRP-2 in colorectal cancer. The link between NRP-2 and colorectal cancer, as well as the mechanism that regulates it, is still mostly unclear. This systematic review was carried out according to the Cochrane guidelines for systematic reviews. We searched PubMed, Embase^®, MEDLINE, Allied & Complementary Medicine^TM, Medical Toxicology & Environmental Health, DH-DATA: Health Administration for articles published before 1 October 2021. The following search terms were used: “neuropilin-2” “neuropilin 2”, “NRP2” and “NRP-2”, “colorectal cancer”, “colon cancer”. Ten articles researching either tumor tissue samples, cell lines, or mice models were included in this review. The majority of human primary and metastatic colon cancer cell lines expressed NRP-2 compared to the normal colonic mucosa. NRPs have been discovered in human cancers as well as neovasculature. The presence of NRP-2 appears to be connected to the epithelial–mesenchymal transition’s function in cancer dissemination and metastatic evolution. The studies were heterogeneous, but the data assessed indicates NRP-2 might have an impact on the metastatic potential of colorectal cancer cells. Nevertheless, further research is needed.

TGF-β superfamily co-receptors in cancer

Transforming growth factor-β (TGF-β) superfamily signaling via their cognate receptors is frequently modified by TGF-β superfamily co-receptors. Signaling through SMAD-mediated pathways may be enhanced or depressed depending on the specific co-receptor and cell context. This dynamic effect on signaling is further modified by the release of many of the co-receptors from the membrane to generate soluble forms that are often antagonistic to the membrane-bound receptors. The co-receptors discussed here include TβRIII (betaglycan), endoglin, BAMBI, CD109, SCUBE proteins, neuropilins, Cripto-1, MuSK, and RGMs. Dysregulation of these co-receptors can lead to altered TGF-β superfamily signaling that contributes to the pathophysiology of many cancers through regulation of growth, metastatic potential, and the tumor microenvironment. Here we describe the role of several TGF-β superfamily co-receptors on TGF-β superfamily signaling and the impact on cellular and physiological functions with a particular focus on cancer, including a discussion on recent pharmacological advances and potential clinical applications targeting these co-receptors.

Long Non-Coding RNA: A Potential Strategy for the Diagnosis and Treatment of Colorectal Cancer

Colorectal cancer (CRC), being one of the most commonly diagnosed cancers worldwide, endangers human health. Because the pathological mechanism of CRC is not fully understood, there are many challenges in the prevention, diagnosis, and treatment of this disease. Long non-coding RNAs (lncRNAs) have recently drawn great attention for their potential roles in the different stages of CRC formation, invasion, and progression, including regulation of molecular signaling pathways, apoptosis, autophagy, angiogenesis, tumor metabolism, immunological responses, cell cycle, and epithelial-mesenchymal transition (EMT). This review aims to discuss the potential mechanisms of several oncogenic lncRNAs, as well as several suppressor lncRNAs, in CRC occurrence and development to aid in the discovery of new methods for CRC diagnosis, treatment, and prognosis assessment.

Re-Expression of Poly/Oligo-Sialylated Adhesion Molecules on the Surface of Tumor Cells Disrupts Their Interaction with Immune-Effector Cells and Contributes to Pathophysiological Immune Escape

Glycans linked to surface proteins are the most complex biological macromolecules that play an active role in various cellular mechanisms. This diversity is the basis of cell-cell interaction and communication, cell growth, cell migration, as well as co-stimulatory or inhibitory signaling. Our review describes the importance of neuraminic acid and its derivatives as recognition elements, which are located at the outermost positions of carbohydrate chains linked to specific glycoproteins or glycolipids. Tumor cells, especially from solid tumors, mask themselves by re-expression of hypersialylated neural cell adhesion molecule (NCAM), neuropilin-2 (NRP-2), or synaptic cell adhesion molecule 1 (SynCAM 1) in order to protect themselves against the cytotoxic attack of the also highly sialylated immune effector cells. More particularly, we focus on α-2,8-linked polysialic acid chains, which characterize carrier glycoproteins such as NCAM, NRP-2, or SynCam-1. This characteristic property correlates with an aggressive clinical phenotype and endows them with multiple roles in biological processes that underlie all steps of cancer progression, including regulation of cell-cell and/or cell-extracellular matrix interactions, as well as increased proliferation, migration, reduced apoptosis rate of tumor cells, angiogenesis, and metastasis. Specifically, re-expression of poly/oligo-sialylated adhesion molecules on the surface of tumor cells disrupts their interaction with immune-effector cells and contributes to pathophysiological immune escape. Further, sialylated glycoproteins induce immunoregulatory cytokines and growth factors through interactions with sialic acid-binding immunoglobulin-like lectins. We describe the processes, which modulate the interaction between sialylated carrier glycoproteins and their ligands, and illustrate that sialic acids could be targets of novel therapeutic strategies for treatment of cancer and immune diseases.

Role and clinical significance of TGF‑β1 and TGF‑βR1 in malignant tumors (Review)

The appearance and growth of malignant tumors is a complicated process that is regulated by a number of genes. In recent years, studies have revealed that the transforming growth factor-β (TGF-β) signaling pathway serves an important role in cell cycle regulation, growth and development, differentiation, extracellular matrix synthesis and immune response. Notably, two members of the TGF-β signaling pathway, TGF-β1 and TGF-β receptor 1 (TGF-βR1), are highly expressed in a variety of tumors, such as breast cancer, colon cancer, gastric cancer and hepatocellular carcinoma. Moreover, an increasing number of studies have demonstrated that TGF-β1 and TGF-βR1 promote proliferation, migration and epithelial-mesenchymal transition of tumor cells by activating other signaling pathways, signaling molecules or microRNAs (miRs), such as the NF-κB signaling pathway and miR-133b. In addition, some inhibitors targeting TGF-β1 and TGF-βR1 have exhibited positive effects in in vitro experiments. The present review discusses the association between TGF-β1 or TGF-βR1 and tumors, and the development of some inhibitors, hoping to provide more approaches to help identify novel tumor markers to restrain and cure tumors.

Neuropilin-2 Is Associated With Increased Hepatoblastoma Cell Viability and Motility

The neuropilins NRP1 and NRP2 are multifunctional glycoproteins that have been implicated in several cancer-related processes including cell survival, migration, and invasion in various tumor types. Here, we examine the role of neuropilins in hepatoblastoma (HB), the most common pediatric liver malignancy. Using a combination of immunohistochemistry, RNA analysis and western blotting, we observed high level expression of NRP1 and NRP2 in 19 of 20 HB specimens and in a majority of human HB cell lines (HUH6 and five cell lines established from patient-derived xenografts) studied but not in normal hepatocytes. Silencing of NRP2 expression in HUH6 and HB-282 HB cells resulted in decreased cell viability, impaired cytoskeleton remodeling, and reduced cell motility, suggesting that NRP2 contributes to the malignant phenotype. We propose that neuropilins warrant further investigation as biomarkers of HB and potential therapeutic targets.

Novel tumour suppressor roles for GZMA and RASGRP1 in Theileria annulata-transformed macrophages and human B lymphoma cells

Theileria annulata is a tick-transmitted apicomplexan parasite that infects and transforms bovine leukocytes into disseminating tumours that cause a disease called tropical theileriosis. Using comparative transcriptomics we identified genes transcriptionally perturbed during Theileria-induced leukocyte transformation. Dataset comparisons highlighted a small set of genes associated with Theileria-transformed leukocyte dissemination. The roles of Granzyme A (GZMA) and RAS guanyl-releasing protein 1 (RASGRP1) were verified by CRISPR/Cas9-mediated knockdown. Knocking down expression of GZMA and RASGRP1 in attenuated macrophages led to a regain in their dissemination in Rag2/γC mice confirming their role as dissemination suppressors in vivo. We further evaluated the roles of GZMA and RASGRP1 in human B lymphomas by comparing the transcriptome of 934 human cancer cell lines to that of Theileria-transformed bovine host cells. We confirmed dampened dissemination potential of human B lymphomas that overexpress GZMA and RASGRP1. Our results provide evidence that GZMA and RASGRP1 have a novel tumour suppressor function in both T. annulata-infected bovine host leukocytes and in human B lymphomas.

Emerging Roles for Neuropilin-2 in Cardiovascular Disease

Cardiovascular disease, the leading cause of death worldwide, is predominantly associated with atherosclerosis. Atherosclerosis is a chronic inflammatory disease characterised by the narrowing of large to medium-sized arteries due to a build-up of plaque. Atherosclerotic plaque is comprised of lipids, extracellular matrix, and several cell types, including endothelial, immune, and vascular smooth muscle cells. Such narrowing of the blood vessels can itself restrict blood flow to vital organs but most severe clinical complications, including heart attacks and strokes, occur when lesions rupture, triggering the blood to clot and obstructing blood flow further down the vascular tree. To circumvent such obstructions, percutaneous coronary intervention or bypass grafts are often required; however, re-occlusion of the treated artery frequently occurs. Neuropilins (NRPs), a multifunctional family of cell surface co-receptors, are expressed by endothelial, immune, and vascular smooth muscle cells and are regulators of numerous signalling pathways within the vasculature. Here, we review recent studies implicating NRP2 in the development of occlusive vascular diseases and discuss how NRP2 could be targeted for therapeutic intervention.

Neuropilin-2 promotes growth and progression of papillary thyroid cancer cells

OBJECTIVE

Neuropilin-2 (NRP2) is a coreceptor of vascular endothelial growth factor-C/D (VEGF-C/D) and plays the important role in the development of lymphatic endothelial cells, as well as neuronal development. NRP2 is known to affect aggressiveness by increasing expression in various human cancers, but the role of NRP2 in thyroid cancer is not fully understood. The purpose of this study was to investigate the NRP2 expression and its role in regulating the tumor aggressiveness in the papillary thyroid carcinoma (PTC).

METHODS

The NRP2 expression and its clinicopathologic correlation to PTC was determined using the data from the 262 PTC patients at a tertiary referral medical center and The Cancer Genome Atlas (TCGA) database. The potential role of NRP2 in modulating tumor growth, invasion, and metastasis in PTC was examined by using small interfering RNA (siRNA)-mediated knockdown of NRP2.

RESULTS

High expression of NRP2 was significantly associated with capsular invasion, lymphovascular invasion, lymph node metastasis, 5 or more metastatic lymph nodes, and recurrence in PTC patients. In TCGA data, the higher NRP2 expression group was significantly associated with extrathyroid extension, lymph node metastasis, and BRAF^V600E mutation. The siRNA mediated knockdown of NRP2 in the PTC cells reduced the cell proliferation, migration and invasion. We also have confirmed that NRP2 knockdown suppressed epithelial-mesenchymal transition (EMT) by regulating AKT and ERK phosphorylation signaling pathways.

CONCLUSION

Our results suggest that NRP2 regulates tumor progression in PTC and may act as a predictive factor for aggressiveness of PTC.

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.

Linking NRP2 With EMT and Chemoradioresistance in Bladder Cancer

Neuropilin-2 (NRP2) is a prognostic indicator for reduced survival in bladder cancer (BCa) patients. Together with its major ligand, vascular endothelial growth factor (VEGF)-C, NRP2 expression is a predictive factor for treatment outcome in response to radiochemotherapy in BCa patients who underwent transurethral resection. Therefore, we investigated the benefit of combining cisplatin-based chemotherapy with irradiation treatment in the BCa cell line RT112 exhibiting or lacking endogenous NRP2 expression in order to evaluate NRP2 as potential therapeutic target. We have identified a high correlation of NRP2 and the glioma-associated oncogene family zinc finger 2 (GLI2) transcripts in the cancer genome atlas (TCGA) cohort of BCa patients and a panel of 15 human BCa cell lines. Furthermore, we used in vitro BCa models to show the transforming growth factor-beta 1 (TGFβ1)-dependent regulation of NRP2 and GLI2 expression levels. Since NRP2 was shown to bind TGFβ1, associate with TGFβ receptors, and enhance TGFβ1 signaling, we evaluated downstream signaling pathways using an epithelial-to-mesenchymal transition (EMT)-assay in combination with a PCR profiling array containing 84 genes related to EMT. Subsequent target validation in NRP2 knockout and knockdown models revealed secreted phosphoprotein 1 (SPP1/OPN/Osteopontin) as a downstream target positively regulated by NRP2.

Neuropilin 1 modulates TGF‑β1‑induced epithelial‑mesenchymal transition in non‑small cell lung cancer

Previously, the authors reported that neuropilin-1 (NRP1) was significantly increased and acted as a vital promoter in the metastasis of non-small cell lung cancer (NSCLC). However, the regulatory mechanism of NRP1 in NSCLC cell migration and invasion remained unclear. The present study aimed to explore the regulatory mechanism of NRP1 in the transforming growth factor-β (TGF-β) 1-induced migration and invasion of NSCLC cells. The expression level of NRP1 was determined by RT-qPCR analysis in human tissue samples with or without lymph node metastasis. Transwell assay and wound healing assay were conducted to determine the cell migration. Lentivirus-mediated stable knockdown and overexpression of NRP1 cell lines were constructed. Exogenous TGF-β1 stimulation, SIS3 treatment, western blot analysis and in vivo metastatic model were utilized to clarify the underlying regulatory mechanisms. The results demonstrated that the expression of NRP1 was increased in metastatic NSCLC tissues. NRP1 promoted NSCLC metastasis in vitro and in vivo. The Transwell assays, wound healing assays and western blot analysis revealed that the knockdown of NRP1 significantly inhibited TGF-β1-mediated EMT and migratory and invasive capabilities of NSCLC. Furthermore, the overexpression of NRP1 weakened the inhibitory effect of SIS3 on the NSCLC migration and invasion. Co-IP assay revealed that NRP1 interacted with TGFβRII to induce EMT. On the whole, the findings of this study demonstrated that NRP1 was overexpressed in metastatic NSCLC tissues. NRP1 could contributes to TGF-β1-induced EMT and metastasis in NSCLC by binding with TGFβRII.

CUB domain-containing protein 1 (CDCP1) binds transforming growth factor beta family members and increase TGF-β1 signaling pathway

CUB domains are most exclusively found in secreted proteins and in a few transmembrane proteins. These domains are approximately 110 amino acids long and have four conserved cysteines that form a β-sandwich fold. CUB domains proteins are involved in a wide range of biological functions. We have shown that CUB domains from Tolloid/BMP1 can bind BMP4 and block BMP signaling in the developing frog embryo. CUB domain-containing protein 1 (CDCP1) is one of the few transmembrane glycoprotein that contains three extracellular CUB domains and regulates anchorage-independent growth and cancer cell migration through activation of Src kinases. In the extracellular space, only a few proteins were found to interact with CDCP1 and at the moment no ligand was found. We demonstrate by using real time protein interaction on BIAcore chip that CDCP1 CUB domains bind directly to TGF-β1 and BMP4. CDCP1 enhances TGF-β1 signaling reporter activity and phosphorylated Smad2 levels but does not modulate BMP signaling pathway. CDCP1 actions on TGF-β/Smad2 signaling are dependent on Smad2 and TGFRI and do not require Src or PKCδ binding. Our findings uncover a new co-receptor for TGF-β1 and bring up new questions on whether CDCP1 cooperates with TGF-β1 to promote cancer progression.

Neuropilin 1 mediates epicardial activation and revascularization in the regenerating zebrafish heart

Unlike adult mammals, zebrafish can regenerate their heart. A key mechanism for regeneration is the activation of the epicardium, leading to the establishment of a supporting scaffold for new cardiomyocytes, angiogenesis and cytokine secretion. Neuropilins are co-receptors that mediate signaling of kinase receptors for cytokines with crucial roles in zebrafish heart regeneration. We investigated the role of neuropilins in response to cardiac injury and heart regeneration. All four neuropilin isoforms (nrp1a, nrp1b, nrp2a and nrp2b) were upregulated by the activated epicardium and an nrp1a-knockout mutant showed a significant delay in heart regeneration and displayed persistent collagen deposition. The regenerating hearts of nrp1a mutants were less vascularized, and epicardial-derived cell migration and re-expression of the developmental gene wt1b was impaired. Moreover, cryoinjury-induced activation and migration of epicardial cells in heart explants were reduced in nrp1a mutants. These results identify a key role for Nrp1 in zebrafish heart regeneration, mediated through epicardial activation, migration and revascularization.

Neuropilins Controlling Cancer Therapy Responsiveness

Neuropilins (NRPs) are cell surface glycoproteins, acting as co-receptors for secreted Semaphorins (SEMAs) and for members of the vascular endothelial growth factor (VEGF) family; they have been initially implicated in axon guidance and angiogenesis regulation, and more recently in cancer progression. In addition, NRPs have been shown to control many other fundamental signaling pathways, especially mediated by tyrosine kinase receptors (RTKs) of growth factors, such as HGF (hepatocyte growth factor), PDGF (platelet derived growth factor) and EGF (epidermal growth factor). This enables NRPs to control a range of pivotal mechanisms in the cancer context, from tumor cell proliferation and metastatic dissemination, to tumor angiogenesis and immune escape. Moreover, cancer treatment failures due to resistance to innovative oncogene-targeted drugs is typically associated with the activity of alternative RTK-dependent pathways; and neuropilins’ capacity to control oncogenic signaling cascades supports the hypothesis that they could elicit such mechanisms in cancer cells, in order to escape cytotoxic stress and therapeutic attacks. Intriguingly, several studies have recently assayed the impact of NRPs inhibition in combination with diverse anti-cancer drugs. In this minireview, we will discuss the state-of-art about the relevance of NRPs as potential predictive biomarkers of drug response, and the rationale to target these proteins in combination with other anticancer therapies.

Semaphorins as Regulators of Phenotypic Plasticity and Functional Reprogramming of Cancer Cells

Semaphorins, initially found as neuronal guidance cues in embryo development, are now appreciated as major regulators of tissue morphogenesis and homeostasis, as well as of cancer progression. In fact, semaphorin signals have a profound impact on cell morphology, which has been commonly associated with the ability to regulate monomeric GTPases, cell-substrate adhesion, and cytoskeletal dynamics. Recently, however, several reports have indicated a novel and additional function of diverse semaphorins in the regulation of gene expression and cell phenotype plasticity. In this review article, we discuss these novel findings, focusing on the role of semaphorin signals in the regulation of bi-directional epithelial-mesenchymal transitions, stem cell properties, and drug resistance, which greatly contribute to the pathogenesis of cancer.

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.

LncRNA XIST facilitates proliferation and epithelial-mesenchymal transition of colorectal cancer cells through targeting miR-486-5p and promoting neuropilin-2

This study was designed to acertain whether the long noncoding RNA (lncRNA) X-inactive specific transcript (XIST)/miR-486-5p/neuropilin-2 (NRP-2) pathway might promote the viability and epithelial-mesenchymal transition (EMT) of colorectal cancer (CRC) cells. In this investigation, we included 317 pathologically confirmed CRC patients and purchased several human CRC cells (i.e. HCT116, HT29, SW620, and SW480). Moreover, pcDNA3.1-XIST, si-XIST, miR-486-5p mimic, miR-486-5p inhibitor, and pcDNA3.1-NRP-2 were transfected into the CRC cells. And the dual-luciferase reporter gene assay managed to verify the targeted relationships among XIST, miR-486-5p, and NRP-2. Ultimately, the MTT assay, flow cytometry, colony formation assay, and transwell assay were carried out to assess the influence of XIST, miR-486-5p, and NRP-2 on the proliferation, apoptosis, migration, and invasion of CRC cells. Our study results demonstrated that CRC tissues and cells were detected with significantly elevated XIST and NRP-2 expressions as well as markedly reduced miR-486-5p expression when compared with normal tissues and cells (all p < 0.05). Besides this, the highly expressed XIST and NRP-2, as well as the lowly expressed miR-486-5p all could substantially encourage proliferation and EMT of CRC cells and simultaneously restrict apoptosis of the cells ( p < 0.05). Moreover, XIST was found to directly target miR-486-5p, and NRP-2 was directly targeted and modulated by miR-486-5p. Finally, CRC cells of the miR-NC + pcDNA3.1-NRP-2 groups showed stronger proliferation, viability, and EMT than those of miR-NC and miR-486-5p mimic groups ( p < 0.05). In conclusion, the XIST/miR-486 -5p/NRP-2 axis appeared to participate in the progression of CRC, which could assist in developing efficacious therapies for CRC.

USP22 drives colorectal cancer invasion and metastasis via epithelial-mesenchymal transition by activating AP4

Ubiquitin specific peptidase 22 (USP22), a putative cancer stem cell marker, is overexpressed in liver metastases of colorectal cancer (CRC). However, the mechanism by which USP22 promotes CRC metastasis remains largely unknown. Here, we report that USP22 and AP4 are simultaneously overexpressed during TGF-β1-induced CRC cell epithelial-mesenchymal transition (EMT). USP22 up-regulation enhances CRC cell migration and invasion and EMT-related marker and AP4 expression, but these effects are partly blocked by AP4 knockdown. In addition, USP22 binds to the promoter region of AP4 to activate its transcription. In vivo, elevated USP22 expression promotes CRC cell metastasis to the lungs in nude mice, as evidenced by the fact that CRC metastatic nodules stain deeply positive for USP22 and AP4. In human CRC tissues, the genes encoding USP22 and AP4 are overexpressed in metastatic liver lesions compared with primary cancer tissues, and their overexpression is significantly associated with poor CRC patient survival. These findings indicate that USP22 and AP4 may serve as prognostic markers for predicting the risk of developing distant metastases in CRC.

Neuropilin-2 promotes melanoma growth and progression in vivo

Tumor cell interactions with their microenvironment, and neighboring endothelial cells in particular, are critical for tumor cell survival and the metastatic process. Within the spectrum of tumors, melanomas are notorious for their ability to metastasize at a relatively early stage of development; however, little is known about the molecular pathways mediating this process. We recently performed a screen to assess critical mediators of melanoma metastasis by evaluating melanoma-endothelial cell communication. Neuropilin-2 (NRP2), a cell surface receptor involved in angiogenesis and axonal guidance, was found to be an important mediator of melanoma-endothelial cell cross-talk in these studies. Here we seek to further define the role of NRP2 in melanoma growth and progression. We use stable gene silencing of NRP2 in melanomas from varying stages of tumor progression to define the role of NRP2 in melanoma growth, migration, invasion, and metastasis. We found that NRP2 gene silencing in metastatic melanoma cell lines inhibited tumor cell growth in vitro; furthermore, knockdown of NRP2 expression in the metastatic melanoma cell line 1205Lu significantly inhibited in-vivo tumor growth and metastasis. We conclude that NRP2 plays an important role in mediating melanoma growth and metastasis and suggest that targeting this cell surface molecule may represent a significant therapeutic strategy for patients diagnosed with aggressive forms of melanoma.

Cathelicidin LL37 Promotes Epithelial and Smooth-Muscle-Like Differentiation of Adipose-Derived Stem Cells through the Wnt/β-Catenin and NF-κB Pathways

Ureter reconstruction is a difficult procedure in urology. Adipose-derived stem cells (ADSCs), along with multipotency and self-renewal capacity, are a preferred choice for tissue engineering-based ureteral reconstruction. We explored the synergic role of cathelicidin LL37 (LL37) in epithelial and smooth-muscle-like differentiation. ADSCs were separated from adipose tissues of mouse and characterized by flow cytometry. The ADSCs were then stably transfected with pGC-FU-GFP (pGC) or pGC containing full-length LL37 (pGC-LL37), respectively. Cell viability and apoptosis were respectively estimated in the stably transfected cells and non-transfected cells. Then, qRT-PCR and Western blot analysis were used for determinations of epithelial marker expressions after induction by all-trans retinoic acid as well as smooth-muscle-like marker expressions after induction by transforming growth factor-β1. Then, possibly involved signaling pathways and extracellular expression of LL37 were detected. Cell viability and apoptosis were not changed after LL37 overexpression. Expression levels of epithelial and smooth-muscle-like markers were significantly upregulated by LL37 overexpression. Moreover, expressions of key kinases involved in the Wnt/β-catenin pathway as well as epithelial marker were upregulated by the LL37 overexpression, while it was reversed by Wnt/β-catenin inhibitor. Likewise, expressions of key kinases involved in the nuclear factor κB (NF-κB) pathway as well as smooth-muscle-like markers were upregulated by LL37 overexpression, which was reversed by NF-κB inhibitor. LL37 was found in the culture medium. LL37, which could be released into the medium, had no impact on cell proliferation and apoptosis of ADSCs. However, LL37 promoted epithelial and smooth-muscle-like differentiation through activating the Wnt/β-catenin and NF-κB pathways, respectively.

Regulation of EMT in Colorectal Cancer: A Culprit in Metastasis

Epithelial to mesenchymal transition (EMT) is a process during which cells lose their epithelial characteristics, for instance cell polarity and cell-cell contact, and gain mesenchymal properties, such as increased motility. In colorectal cancer (CRC), EMT is associated with an invasive or metastatic phenotype. In this review, we discuss recent studies exploring novel regulation mechanisms of EMT in CRC, including the identification of new CRC EMT regulators. Upregulation of inducers can promote EMT, leading to increased invasiveness and metastasis in CRC. These inducers can downregulate E-cadherin and upregulate N-cadherin and vimentin (VIM) through modulating EMT-related signaling pathways, for instance WNT/β-catenin and TGF-β, and EMT transcription factors, such as zinc finger E-box binding homeobox 1 (ZEB1) and ZEB2. In addition, several microRNAs (miRNAs), including members of the miR-34 and miR-200 families, are found to target mRNAs of EMT-transcription factors, for example ZEB1, ZEB2, or SNAIL. Downregulation of these miRNAs is associated with distant metastasis and advanced stage tumors. Furthermore, the role of EMT in circulating tumor cells (CTCs) is also discussed. Mesenchymal markers on the surface of EMT CTCs were found to be associated with metastasis and could serve as potential biomarkers for metastasis. Altogether, these studies indicate that EMT is orchestrated by a complicated network, involving regulators of different signaling pathways. Further studies are required to understand the mechanisms underlying EMT in CRC.

Downregulating Neuropilin-2 Triggers a Novel Mechanism Enabling EGFR-Dependent Resistance to Oncogene-Targeted Therapies

Neuropilins are a class of cell surface proteins implicated in cell migration and angiogenesis, with aberrant expression in human tumors. Here, we show that the expression of Neuropilin-2 (NRP2) controls EGFR protein levels, thereby impinging on intracellular signaling, viability, and response to targeted therapies of oncogene-addicted cells. Notably, increased NRP2 expression in EGFR-addicted tumor cells led to downregulation of EGFR protein and tumor cell growth inhibition. NRP2 also blunted upregulation of an EGFR "rescue" pathway induced by targeted therapy in Met-addicted carcinoma cells. Cancer cells acquiring resistance to MET oncogene-targeted drugs invariably underwent NRP2 loss, a step required for EGFR upregulation. Mechanistic investigations revealed that NRP2 loss activated NFkB and upregulated the EGFR-associated protein KIAA1199/CEMIP, which is known to oppose the degradation of activated EGFR kinase. Notably, KIAA1199 silencing in oncogene-addicted tumor cells improved therapeutic responses and counteracted acquired drug resistance. Our findings define NRP2 as the pivotal switch of a novel broad-acting and actionable pathway controlling EGFR signaling, and driving resistance to therapies targeting oncogene-addiction.Significance: These important findings identify the cell surface molecule Nrp2 as the pivotal switch of a novel, actionable pathway driving EGFR upregulation and resistance to oncogene- targeted therapies. Cancer Res; 78(4); 1058-68. ©2017 AACR.

Clusterin and neuropilin-2 as potential biomarkers of tumor progression in benzo[a]pyrene-transformed 16HBE cells xenografted nude mouse model

Benzo[a]pyrene (BaP) is a ubiquitous environment contaminant and its exposure could increase incidence of human lung cancer. In order to confirm and compare potential biomarkers of BaP-induce carcinogenesis and tumor progression, time-dependent changes of clusterin (CLU) and neuropilin-2 (NRP2) levels were evaluated in sera of BaP-transformed 16HBE cell line T-16HBE-C1 cells xenografted nude mice. Performance of CLU and NRP2 on tissue classification and tumor progression forecast was also calculated. Levels of CLU and NRP2 were significant elevated in both culture supernatant of T-16HBE-C1 cells and sera of T-16HBE-C1 cells xenografted nude mice compared with control. CLU and NRP2 were both found positively stained in tumor tissue. CLU and NRP2 alone could well predicate tumor progression in nude mice and CLU appeared to be more sensitive than NRP2. When both of them combined, performance of predication would improve. In conclusion, CLU and NRP2 could serve as potential biomarkers of tumor progression in nude mice xenografted with T-16HBE-C1 cells.

The receptor tyrosine kinase AXL promotes migration and invasion in colorectal cancer

The receptor tyrosine kinases (RTKs) TYRO3, AXL and MERTK (TAM) have well-described oncogenic functions in a number of cancers. Notwithstanding, TAM RTKs are also potent and indispensable inhibitors of inflammation. The combined deletion of Axl and Mertk in mice enhances chronic inflammation and autoimmunity, including increased inflammation in the gut and colitis-associated cancer. On the other hand, deletion of Tyro3 increases the risk of allergic responses. Therefore, the indiscriminate inhibition of these TAM RTKs could result in undesirable immunological diseases. Here we show that AXL, but not MERTK or TYRO3 expression is enhanced in late stage colorectal cancer (CRC) and AXL expression associates with a cell migration gene signature. Silencing AXL or the inhibition of AXL kinase activity significantly inhibits tumor cell migration and invasion. These results indicate that the selective inhibition of AXL alone might confer sufficient therapeutic benefit in CRC, while preserving at least some of the beneficial, anti-inflammatory effects of MERTK and TYRO3 RTKs.

Inflammation and Lymphedema Are Exacerbated and Prolonged by Neuropilin 2 Deficiency

The vasculature influences the progression and resolution of tissue inflammation. Capillaries express vascular endothelial growth factor (VEGF) receptors, including neuropilins (NRPs), which regulate interstitial fluid flow. NRP2, a receptor of VEGFA and semaphorin (SEMA) 3F ligands, is expressed in the vascular and lymphatic endothelia. Previous studies have demonstrated that blocking VEGF receptor 2 attenuates VEGFA-induced vascular permeability. The inhibition of NRP2 was hypothesized to decrease vascular permeability as well. Unexpectedly, massive tissue swelling and edema were observed in Nrp2^-/- mice compared with wild-type littermates after delayed-type hypersensitivity reactions. Vascular permeability was twofold greater in inflamed blood vessels in Nrp2-deficient mice compared to those in Nrp2-intact littermates. The addition of exogenous SEMA3F protein inhibited vascular permeability in Balb/cJ mice, suggesting that the loss of endogenous Sema3F activity in the Nrp2-deficient mice was responsible for the enhanced vessel leakage. Functional lymphatic capillaries are necessary for draining excess fluid after inflammation; however, Nrp2-mutant mice lacked superficial lymphatic capillaries, leading to 2.5-fold greater fluid retention and severe lymphedema after inflammation. In conclusion, Nrp2 deficiency increased blood vessel permeability and decreased lymphatic vessel drainage during inflammation, highlighting the importance of the NRP2/SEMA3F pathway in the modulation of tissue swelling and resolution of postinflammatory edema.

Regulation of the Bioavailability of TGF-β and TGF-β-Related Proteins

The bioavailability of members of the transforming growth factor β (TGF-β) family is controlled by a number of mechanisms. Bona fide TGF-β is sequestered into the matrix in a latent state and must be activated before it can bind to its receptors. Here, we review the molecules and mechanisms that regulate the bioavailability of TGF-β and compare these mechanisms with those used to regulate other TGF-β family members. We also assess the physiological significance of various latent TGF-β activators, as well as other extracellular modulators of TGF-β family signaling, by examining the available in vivo data from knockout mouse models and other biological systems.

Regulation of the Bioavailability of TGF-β and TGF-β-Related Proteins

The bioavailability of members of the transforming growth factor β (TGF-β) family is controlled by a number of mechanisms. Bona fide TGF-β is sequestered into the matrix in a latent state and must be activated before it can bind to its receptors. Here, we review the molecules and mechanisms that regulate the bioavailability of TGF-β and compare these mechanisms with those used to regulate other TGF-β family members. We also assess the physiological significance of various latent TGF-β activators, as well as other extracellular modulators of TGF-β family signaling, by examining the available in vivo data from knockout mouse models and other biological systems.

Neuropilin-2 promotes tumourigenicity and metastasis in oesophageal squamous cell carcinoma through ERK-MAPK-ETV4-MMP-E-cadherin deregulation

Oesophageal squamous cell carcinoma (ESCC) is the most common histological subtype of oesophageal cancer. The disease is particularly prevalent in southern China. The incidence of the disease is on the rise and its overall survival rate remains dismal. Identification and characterization of better molecular markers for early detection and therapeutic targeting are urgently needed. Here, we report levels of transmembrane and soluble neuropilin-2 (NRP2) to be significantly up-regulated in ESCC, and to correlate positively with advanced tumour stage, lymph node metastasis, less favourable R category and worse overall patient survival. NRP2 up-regulation in ESCC was in part a result of gene amplification at chromosome 2q. NRP2 overexpression promoted clonogenicity, angiogenesis and metastasis in ESCC in vitro, while NRP2 silencing by lentiviral knockdown or neutralizing antibody resulted in a contrary effect. This observation was extended in vivo in animal models of subcutaneous tumourigenicity and tail vein metastasis. Mechanistically, overexpression of NRP2 induced expression of ERK MAP kinase and the transcription factor ETV4, leading to enhanced MMP-2 and MMP-9 activity and, as a consequence, suppression of E-cadherin. In summary, NRP2 promotes tumourigenesis and metastasis in ESCC through deregulation of ERK-MAPK-ETV4-MMP-E-cadherin signalling. NRP2 represents a potential diagnostic or prognostic biomarker and therapeutic target for ESCC. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Label-free quantitative proteomic analysis of benzo(a)pyrene-transformed 16HBE cells serum-free culture supernatant and xenografted nude mice sera

To screen potential biomarkers of benzo(a)pyrene (BaP)-induced lung cancer, the proteomic profiles of BaP-transformed 16HBE cell line T-16HBE-C1 cells serum-free culture supernatant and xenografted nude mice sera were compared with those of 16HBE group by utilizing label-free quantitative proteomic strategy. By employing nano-LC-MS/MS technology followed by MaxQuant and Perseus processing, 489 differentially expressed proteins were identified between T-16HBE-C1 and 16HBE cells serum-free culture supernatant, and 49 significantly up-regulated proteins were identified in T-16HBE-C1 xenografted nude mice sera. Three proteins neuropilin-2 (NRP2), clusterin (CLU) and A-kinase anchor protein 12 (AKAP12) were up-regulated in the serum-free culture supernatant of T-16HBE-C1 cells. These 3 human proteins were present in the sera of nude mice xenografted with T-16HBE-C1 cells, but were undetectable in mice xenografted with 16HBE cells. The proteomic results of NRP2 and AKAP12 were confirmed by Western blotting and enzyme-linked immunosorbent assays, respectively. Moreover, the serum NRP2 levels were significantly elevated at the 4th day after tumor cell implantation and showed good positive correlation with tumor growth characterized by tumor volume. In conclusion, serum NRP2, CLU and AKAP12 could be potential biomarkers of BaP-induced lung cancer. The proteomic results will gain deeper insights into the mechanisms of BaP-induced carcinogenesis.

Epithelial-Mesenchymal Transition (EMT) Gene Variants and Epithelial Ovarian Cancer (EOC) Risk

Epithelial-mesenchymal transition (EMT) is a process whereby epithelial cells assume mesenchymal characteristics to facilitate cancer metastasis. However, EMT also contributes to the initiation and development of primary tumors. Prior studies that explored the hypothesis that EMT gene variants contribute to epithelial ovarian carcinoma (EOC) risk have been based on small sample sizes and none have sought replication in an independent population. We screened 15,816 single-nucleotide polymorphisms (SNPs) in 296 genes in a discovery phase using data from a genome-wide association study of EOC among women of European ancestry (1,947 cases and 2,009 controls) and identified 793 variants in 278 EMT-related genes that were nominally (P < 0.05) associated with invasive EOC. These SNPs were then genotyped in a larger study of 14,525 invasive-cancer patients and 23,447 controls. A P-value <0.05 and a false discovery rate (FDR) <0.2 were considered statistically significant. In the larger dataset, GPC6/GPC5 rs17702471 was associated with the endometrioid subtype among Caucasians (odds ratio (OR) = 1.16, 95% CI = 1.07-1.25, P = 0.0003, FDR = 0.19), whereas F8 rs7053448 (OR = 1.69, 95% CI = 1.27-2.24, P = 0.0003, FDR = 0.12), F8 rs7058826 (OR = 1.69, 95% CI = 1.27-2.24, P = 0.0003, FDR = 0.12), and CAPN13 rs1983383 (OR = 0.79, 95% CI = 0.69-0.90, P = 0.0005, FDR = 0.12) were associated with combined invasive EOC among Asians. In silico functional analyses revealed that GPC6/GPC5 rs17702471 coincided with DNA regulatory elements. These results suggest that EMT gene variants do not appear to play a significant role in the susceptibility to EOC.

Neuropilin-2 induced by transforming growth factor-β augments migration of hepatocellular carcinoma cells

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common form of liver cancer and the third most lethal cancer worldwide. The epithelial to mesenchymal transition (EMT) describes the transformation of well-differentiated epithelial cells to a de-differentiated phenotype and plays a central role in the invasion and intrahepatic metastasis of HCC cells. Modulation of the transforming growth factor-β (TGF-β) signaling is known to induce various tumor-promoting and EMT-inducing pathways in HCC. The meta-analysis of a panel of EMT gene expression studies revealed that neuropilin 2 (NRP2) is significantly upregulated in cells that have undergone EMT induced by TGF-β. In this study we assessed the functional role of NRP2 in epithelial and mesenchymal-like HCC cells and focused on the molecular interplay between NRP2 and TGF-β/Smad signaling.

METHODS

NRP2 expression was analyzed in human HCC cell lines and tissue arrays comprising 133 HCC samples. Cell migration was examined by wound healing and Transwell assays in the presence and absence of siRNA against NRP2. NRP2 and TGF-β signaling were analyzed by Western blotting and confocal immunofluorescence microscopy.

RESULTS

We show that NRP2 is particularly expressed in HCC cell lines with a dedifferentiated, mesenchymal-like phenotype. NRP2 expression is upregulated by the canonical TGF-β/Smad signaling while NRP2 expression has no impact on TGF-β signaling in HCC cells. Reduced expression of NRP2 by knock-down or inhibition of TGF-β signaling resulted in diminished cell migration independently of each other, suggesting that NRP2 fails to collaborate with TGF-β signaling in cell movement. In accordance with these data, elevated levels of NRP2 correlated with a higher tumor grade and less differentiation in a large collection of human HCC specimens.

CONCLUSIONS

These data suggest that NRP2 associates with a less differentiated, mesenchymal-like HCC phenotype and that NRP2 plays an important role in tumor cell migration upon TGF-β-dependent HCC progression.

Regulation of epithelial-mesenchymal transition by tumor-associated macrophages in cancer

It should be urgently better understood of the mechanism that contributes cancer aggressiveness. Epithelial-mesenchymal transition (EMT) plays a fundamental role in tumor progression and metastasis formation by invasion, resistance to cell death and senescence, resistance to chemotherapy and immunotherapy, immune surveillance, immunosuppression and inflammation, confers stem cell properties. Tumor-associated macrophages (TAMs) are key orchestrators and a set of macrophages in tumor microenvironment. They are major players in the connection between inflammation and cancer. TAMs could promote proliferation, invasion and metastasis of tumor cells, stimulate tumor angiogenesis, and inhibit anti-tumor immune response mediated by T cell followed by promoting tumor progression. Recently, studies showed that TAMs played critical role in the regulation of EMT in cancer, although the underlying mechanism of TAMs-mediated acquisition of EMT has been largely unclear. This review will discuss recent advances in our understanding of the role of TAMs in the regulation of EMT during tumorigenesis and summarize the recent ongoing experimental and pre-clinical TAMs targeted studies.

[The metastatic niche. Mechanisms and prognostic implications]

Disseminated tumor cells require a special microenvironment to form metastases. This metastatic niche is organ specific and forms prior to the establishment of visible metastases. The niche is characterized by vascular remodeling and bone marrow-derived cells which have migrated into it. Studies by other groups and our own results have already shown that intranodal lymphangiogenesis is an important prerequisite for regional lymph node metastases in rectal cancer patients, and can be used as a prognostic marker for progression-free survival. Niche cells such as endothelia secrete factors that attract tumor and bone marrow-derived cells. CXCL12 is one of these factors. CXCL12 activates the CXCR4 chemokine axis and induces migration along its gradient. Several factors, such as hypoxia, have been described to regulate CXCR4 function and surface expression on tumor cells. Low molecular weight agents have been used to block CXCR4 activation. This review focuses on the function and regulation of CXCR4 and its ligand CXCL12 in metastases formation. It also discusses potential options for therapeutic blockage.

Class 3 semaphorins negatively regulate dermal lymphatic network formation

The development of a patterned lymphatic vascular network is essential for proper lymphatic functions during organ development and homeostasis. Here we report that class 3 semaphorins (SEMA3s), SEMA3F and SEMA3G negatively regulate lymphatic endothelial cell (LEC) growth and sprouting to control dermal lymphatic network formation. Neuropilin2 (NRP2) functions as a receptor for SEMA3F and SEMA3G, as well as vascular endothelial growth factor C (VEGFC). In culture, Both SEMA3F and SEMA3G inhibit VEGFC-mediated sprouting and proliferation of human dermal LECs. In the developing mouse skin, Sema3f is expressed in the epidermis and Sema3g expression is restricted to arteries, whereas their receptor Nrp2 is preferentially expressed by lymphatic vessels. Both Sema3f;Sema3g double mutants and Nrp2 mutants exhibit increased LEC growth in the skin. In contrast, Sema3f;Sema3g double mutants display increased lymphatic branching, while Nrp2 mutants exhibit reduced lymphatic branching. A targeted mutation in PlexinA1 or PlexinA2, signal transducers forming a receptor complex with NRP2 for SEMA3s, exhibits an increase in LEC growth and lymphatic branching as observed in Sema3f;Sema3g double mutants. Our results provide the first evidence that SEMA3F and SEMA3G function as a negative regulator for dermal lymphangiogenesis in vivo. The reciprocal phenotype in lymphatic branching between Sema3f;Sema3g double mutants and Nrp2 mutants suggest a complex NRP2 function that regulates LEC behavior both positively and negatively, through a binding with VEGFC or SEMA3s.

Neuropilin-2 Is a Newly Identified Target of PAX8 in Thyroid Cells

PAX8 is a transcription factor essential for thyroid gland development, as well as for the maintenance of the thyroid differentiated state in the adult. In particular, PAX8 has been comprehensively shown to regulate genes that are considered markers of thyroid differentiation. However, a better knowledge of genes transcriptionally regulated by PAX8 is desirable to clarify its role in endocrine syndromes and cancer susceptibility. In order to further investigate PAX8 downstream targets, we recently performed a genome-wide expression analysis following PAX8 knockdown in FRTL-5 thyroid cells and Neuropilin-2 was identified as a potential transcriptional target of PAX8. In this study, we determined the role of the transcription factor PAX8 in the regulation of Neuropilin-2 expression. Indeed, in thyroid cells PAX8 directly binds the Neuropilin-2 promoter leading to its transcriptional repression. Interestingly, we observed an inverse correlation between the expression of PAX8 and Neuropilin-2 in thyroid carcinoma tissues and cell lines compared to non-tumor counterparts, suggesting a critical role of PAX8 in regulating Neuropilin-2 expression in vivo. Notably, ectopic overexpression of PAX8 in FB-2 thyroid cancer cells promotes Neuropilin-2 downregulation producing a significant reduction in cell proliferation, migration ability, and invasion activity and reverting the cell phenotype from mesenchymal to a more epithelial one. These findings uncover the novel interplay between PAX8 and Neuropilin-2, which is likely to be important in the pathogenesis of thyroid diseases.

Neuropilin-2 expression is inhibited by secreted Wnt antagonists and its down-regulation is associated with reduced tumor growth and metastasis in osteosarcoma

Background

Neuropilin 2 (NRP2) isa multi-functional co-receptor to many receptors, including VEGF receptor, c-Met and others. NRP2 has recently been implicated in tumor angiogenesis, growth, and metastasis of many other cancers. However, its role in osteosarcoma remains poorly understood.

Results

NRP2 was overexpressed in osteosarcoma cell lines and tissues, and associated with poor survival of osteosarcoma patients. Knockdown of NRP2 expression by short-hairpin (Sh) RNA resulted in reduced tumor growth, metastasis, and blood vessel formation of osteosarcoma. Knockdown of NRP2 expression by ShRNA also inhibited the recruitment of HUVEC cells to osteosarcoma cells. Inhibition of Wnt signaling by overexpression of secreted Wnt antagonists soluble LRP5, Frzb, and WIF1 markedly down-regulated mRNA and protein expression of NRP2 in osteosarcoma cell lines.

Conclusions

Regulation of NRP2 receptor expression may represent a novel approach for treatment of osteosarcoma through retarding osteosarcoma growth, metastasis and blood vessel formation. In addition, down-regulation of NRP2 expression can be achieved by expression of secreted Wnt antagonists.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0359-4) contains supplementary material, which is available to authorized users.