8828

NRP2

neuropilin 2;NRP2;neuropilin 2

neuropilin-2|neuropilin-2a(17)|neuropilin-2a(22)|neuropilin-2b(0)|receptor for VEGF165 and semaphorins class3|vascular endothelial cell growth factor 165 receptor 2

2q33.3

protein-coding

BACKGROUND: Neuropilin-2 (Nrp2) is a receptor for vascular endothelial growth factor-C (VEGF-C), which is a well-known lymphangiogenic factor and plays an important role in lymph node metastasis of various human cancers, including breast cancer. Recently, Nrp2 was shown to play a role in cancer by promoting tumor cell metastasis. CXC chemokine receptor 4 (CXCR4) also promotes tumor metastasis. In the previous studies, we demonstrated that VEGF-C and cytoplasmic CXCR4 expressions were correlated with poorer patient prognosis (BMC cancer 2008,8:340; Breast cancer Res Treat 2005, 91:125-132). METHODS: The relationship between Nrp2 expression and lymph node metastasis, VEGF-C expression, CXCR4 expression, and other established clinicopathological variables (these data were cited in our previous papers), including prognosis, was analyzed in human breast cancer. Effects of neutralizing anti-Nrp2 antibody on CXCR4 expression and chemotaxis were assessed in MDA-MB-231 breast cancer cells. RESULTS: Nrp2 expression was observed in 53.1% (60 of 113) of the invasive breast carcinomas. Nrp2 expression was significantly correlated with lymph node metastasis, VEGF-C expression, and cytoplasmic CXCR4 expression. Survival curves determined by the Kaplan-Meier method showed that Nrp2 expression was associated with reduced overall survival. In multivariate analysis, Nrp2 expression emerged as a significant independent predictor for overall survival. Neutralizing anti-Nrp2 antibody blocks cytoplasmic CXCR4 expression and CXCR4-induced migration in MDA-MB-231 cells. CONCLUSION: Nrp2 expression was correlated with lymph node metastasis, VEGF-C expression, and cytoplasmic CXCR4 expression. Nrp2 expression may serve as a significant prognostic factor for long-term survival in breast cancer. Our data also showed a role for Nrp2 in regulating cytoplasmic CXCR4 expression in vitro.

Neuropilin-2 (NRP2) is a receptor expressed by tumor cells and endothelial cells (EC) that binds both semaphorin 3F (SEMA3F), a potent inhibitor of tumor angiogenesis and metastasis, and vascular endothelial growth factor (VEGF), a potent stimulator of tumor angiogenesis. It was found that glioblastoma and melanoma cells repressed NRP2 expression when maintained under hypoxic conditions and after treatment with the hypoxia-mimetic agent desferrioxamine (DFO), at both the mRNA and protein levels. Silencing of HIF1-alpha, the hypoxia-induced subunit of the hypoxia inducible factor (HIF), abrogated DFO-induced NRP2 repression. Conversely, ectopic expression of HIF1-alpha directly repressed NRP2 promoter activity and expression. NRP2 is the sole receptor for SEMA3F. Loss of NRP2 expression in tumor cells inhibited SEMA3F-dependent activities, such as inactivation of RhoA, depolymerization of F-actin, and inhibition of tumor cell migration. On the other hand, loss of NRP2 expression in tumor cells increased VEGF protein levels in conditioned media, with no effects on VEGF mRNA levels. This increase in VEGF protein levels promoted paracrine activation of EC, including VEGF receptor-2 phosphorylation, and activation of downstream signaling proteins such as p44/42 MAPK and p38 MAPK. In addition, the elevated VEGF levels induced EC migration and sprouting, two key steps of tumor angiogenesis in vivo. It was concluded that hypoxia regulates VEGF and SEMA3F activities through transcriptional repression of their common receptor NRP2, providing a novel mechanism by which hypoxia induces tumor angiogenesis, growth and metastasis.

CONTEXT: Neuropilin-2 (Nrp2) is a coreceptor for vascular endothelial growth factor-D (VEGF-D) that is expressed on the surface of endothelial cells. Recently, Nrp2 was shown to play a role in lymph node metastasis and promotion of cancer cell migration. VEGF-D also promotes lymphangiogenesis, which in turn promotes tumor metastasis. OBJECTIVE: The aim was to study the role of neuropilin-2 in lymph node metastasis in human papillary thyroid carcinoma (PTC). DESIGN: expression of Nrp2 was studied by immunohistochemistry and the relationship between Nrp2 expression and lymph node metastasis, VEGF-D expression and other established clinicopathological variables were analyzed in PTC. The effects of neutralizing anti-Nrp2 antibody on VEGF-D-induced invasion and migration were assessed in PTC cell lines. RESULTS: Nrp2 expression was observed in 64.3% (36 of 56) of the PTC patients. Nrp2 expression was significantly correlated with lymph node metastasis (P = 0.0216) and VEGF-D expression (P = 0.0034). VEGF-D was shown to promote filopodia formation and cancer cell migration and invasion by K1 and B-CPAP cells. These responses were significantly blocked by neutralizing anti-Nrp2 antibody. CONCLUSION: Nrp2 expression was correlated with lymph node metastasis and VEGF-D expression in PTC. Our data also showed a role for Nrp2 in regulating VEGF-D-induced invasion and migration in vitro.