Neuropilins in physiological and pathological angiogenesis

Neuropilin-1 (Np1) and neuropilin-2 (Np2) are transmembrane glycoproteins with large extracellular domains that interact with both class 3 semaphorins and vascular endothelial growth factor (VEGF), and are involved in the regulation of many physiological pathways, including angiogenesis. The neuropilins also interact directly with the classical receptors for VEGF, VEGF-R1 and -R2, mediating signal transduction. The heart, glomeruli and osteoblasts express both Np1 and Np2, but there is differential expression in the adult vasculature, with Np1 expressed mainly by arterial endothelium, whereas Np2 is only expressed by venous and lymphatic endothelium. Both neuropilins are commonly over-expressed in regions of physiological (wound-healing) and pathological (tumour) angiogenesis, but the signal transduction pathways, neuropilin-mediated gene expression and the definitive role of neuropilins in angiogenic processes are not fully characterized. This review details the current evidence for the role of neuropilins in angiogenesis, and suggests future research directions that may enhance our understanding of the mechanisms of action of this unique family of proteins.     

Expression of VEGF,semaphorin SEMA3F,and their common receptors neuropilins NP1 and NP2 in preinvasive bronchial lesions,lung tumours,and cell lines

Two receptors, neuropilin 1 (NP1) and neuropilin 2 (NP2), bind class 3 semaphorins, axon guidance molecules including SEMA3F, the gene for which was isolated from a 3p21.3 deletion in lung cancer. In addition, they bind VEGF (vascular endothelial growth factor), enhancing the effects of VEGF binding to KDR/Flk-1. Elevated VEGF levels are associated with the loss and cytoplasmic delocalization of SEMA3F in lung cancer, suggesting competition for their NP1 and NP2 receptors. To determine the timing of these events, we compared by immunohistochemistry VEGF, SEMA3F, NP1 and NP2 expression in 50 preneoplastic lesions and 112 lung tumours. In preneoplastic lesions, VEGF increased from low-grade to high-grade dysplasia (p=0.001) whereas SEMA3F levels remained low. NP1 and NP2 levels increased from dysplasia to microinvasive carcinoma (p=0.0001) and correlated with VEGF expression (p=0.04 and 0.0002, respectively). Non-small cell lung carcinoma overexpressed VEGF and NP1 and NP2 significantly more often than neuroendocrine tumours including small cell lung carcinoma. SEMA3F loss or delocalization correlated with advanced tumour stage. Migrating cells overexpressed VEGF, SEMA3F, NP1 and NP2 with cytoplasmic delocalization of NP1 as demonstrated in an in vitro wound assay. These results demonstrate early alteration of the VEGF/SEMA3F/NP pathway in lung cancer progression.     

Migration-promoting role of VEGF-C and VEGF-C binding receptors in human breast cancer cells

Vascular endothelial growth factor C (VEGF-C) is a lymphangiogenic factor over-expressed in highly metastatic, cyclooxygenase (COX)-2 expressing breast cancer cells. We tested the hypothesis that tumour-derived VEGF-C may play an autocrine role in metastasis by promoting cellular motility through one or more VEGF-C-binding receptors VEGFR-2, VEGFR-3, neuropilin (NRP)-1, NRP-2, and integrin alpha9beta1. We investigated the expression of these receptors in several breast cancer cell lines (MDA-MB-231, Hs578T, SK-BR-3, T-47D, and MCF7) and their possible requirement in migration of two VEGF-C-secreting, highly metastatic lines MDA-MB-231 and Hs578T. While cell lines varied significantly in their expression of above VEGF-C receptors, migratory activity of MDA-MB-231 and Hs578T cells was linked to one or more of these receptors. Depletion of endogenous VEGF-C by treatments with a neutralising antibody, VEGF-C siRNA or inhibitors of Src, EGFR/Her2/neu and p38 MAP kinases which inhibited VEGF-C production, inhibited cellular migration, indicating the requirement of VEGF-C for migratory function. Migration was differentially attenuated by blocking or downregulation of different VEGF-C receptors, for example treatment with a VEGFR-2 tyrosine kinase inhibitor, NRP-1 and NRP-2 siRNA or alpha9beta1 integrin antibody, indicating the participation of one or more of the receptors in cell motility. This novel role of tumour-derived VEGF-C indicates that breast cancer metastasis can be promoted by coordinated stimulation of lymphangiogenesis and enhanced migratory activity of breast cancer cells.     

Neuropilin‐1 interacts with the second branchial arch microenvironment to mediate chick neural crest cell dynamics

Cranial neural crest cells (NCCs) require neuropilin signaling to reach and invade the branchial arches. Here, we use an in vivo chick model to investigate whether the neuropilin‐1 knockdown phenotype is specific to the second branchial arch (ba2), changes in NCC behaviors and phenotypic consequences, and whether neuropilins work together to facilitate entry into and invasion of ba2. We find that cranial NCCs with reduced neuropilin‐1 expression displayed shorter protrusions and decreased cell body and nuclear length‐to‐width ratios characteristic of a loss in polarity and motility, after specific interaction with ba2. Directed NCC migration was rescued by transplantation of transfected NCCs into rhombomere 4 of younger hosts. Lastly, reduction of neuropilin‐2 expression by shRNA either solely or with reduction of neuropilin‐1 expression did not lead to a stronger head phenotype. Thus, NCCs, independent of rhombomere origin, require neuropilin‐1, but not neuropilin‐2 to maintain polarity and directed migration into ba2. Developmental Dynamics 239:1664–1673, 2010. © 2010 Wiley‐Liss, Inc.     

基于microRNA调控网络预测卵巢癌多药耐药相关基因

目的:基于microRNA(miRNA)调控网络预测卵巢癌多药耐药相关基因。方法:综合运用文本挖掘、网络构建和预测等生物信息学分析方法,挖掘卵巢癌化疗耐药相关miRNA和miRNA-靶基因数据,并构建miRNA调控网络,利用已知miRNA对卵巢癌多药耐药相关基因进行预测。结果:文本挖掘出11个与卵巢癌化疗耐药相关的miRNA,包括miR-130a、miR-214、let-7i、miR-125b、miR-376c、miR-199a、miR-93、miR-141、miR-130b、miR-193b*和miR-200c。在miRNA靶基因预测数据软件Target Scan中挖掘出47 077个miRNA-靶基因数据,而Pic Tar挖掘出1 675个miRNA-靶基因数据。在miRNA调控网络中,神经素1基因(neuropilins,NRP1)是最重要的Hub-基因。结论:利用已知miRNA构建miRNA调控网络进而预测卵巢癌多药耐药相关基因是一种行之有效的方法。NRP1极有可能在卵巢癌化疗耐药形成中扮演着重要的角色,是卵巢癌潜在的药物治疗靶点。     

Neuropilins在肿瘤中的多功能作用机制

神经纤毛蛋白（NRPs）是一种调控胚胎组织发育、体内稳态以及癌症进展的跨膜糖蛋白。这篇综述讨论NRPs在各种癌症中的功能及其潜在机制,重点是NRPs在多功能细胞因子转化生长因子-β1（TGF-β1）信号传导途径、上皮-间质转化（EMT）、癌症干细胞（CSC）特性和药物抵抗调节中的作用,探讨NRPs调节作用如何促进细胞可塑性、肿瘤进展及转移。最后,讨论了NRPs在靶向治疗中的广泛应用前景。     

神经纤毛蛋白1、2在大肠癌组织中的表达及意义

【摘要】目的 探讨神经纤毛蛋白（NRP）-1、2 在大肠癌组织中的表达及其与微血管密度（MVD）的相关性,以揭示NRP-1、2 与肿瘤血管生成的关系。方法 采用免疫组织化学方法检测66 例大肠癌患者的癌组织、癌旁组织及正常组织中NRP-1、2 的表达情况,以CD105 标记肿瘤新生血管内皮细胞,计数MVD 值。结果 （1）NRP-1、NRP-2 在大肠癌组织、癌旁组织、正常组织中的表达阳性率分别为71.2%、25.8%、0,及80.3%、15.2%、0,各组间比较差异有统计学意义(P＜0.01)。（2）MVD 在大肠癌组织、癌旁组织及正常组织中的计数分别为35.682±5.542、14.485±3.301、 6.864±1.771,各组相比差异有统计学意义（F=986.654,P＜0.01）。（3）不同年龄、性别、肿瘤的部位及分化程度的患者 NRP-1、2 的表达差异无统计学意义。肿瘤＞5 cm 的患者NRP-1 阳性表达率较高,肿瘤侵及浆膜及以外、有淋巴结转移的患者NRP-1、2 的阳性表达率均较高,不同的Dukes 分期患者NRP-1、2 阳性表达差异亦有统计学意义（P＜ 0.05）。（4）大肠癌患者不同性别、年龄及肿瘤大小、部位和组织分化程度MVD 的表达差异无统计学意义,而浸润到浆膜及以外、有淋巴结转移、Dukes 分期高的患者相关MVD 的表达增加(P＜0.01)。（5）大肠癌组织中NRP-1（r=0.599, P＜0.01）、NRP-2（r=0.484,P＜0.01）的表达与MVD 计数均呈正相关关系。结论 NRP-1、2 在大肠癌的血管新生中起重要作用,并且与大肠癌侵袭和转移关系密切。