The NRP1 gene regulates proliferation, apoptosis, migration, and invasion in T24 and 5637 bladder cancer cells

Background Bladder urothelial carcinoma (BC) is a fatal invasive malignancy and the most common malignancy of the urinary system. In the current study, we investigate the function and mechanisms of Neuropilin-1 (NRP1), the co-receptor for vascular endothelial growth factor, in BC pathogenesis and progression. Methods The expression of NRP1 was assessed in several BC cell lines. Additionally, the biological function of NRP1 in proliferation, apoptosis, angiogenesis, migration, and invasion of BC were validated in vitro by silencing NRP1. Moreover, gene expression profiling chip analysis was conducted, and the related signalling pathways were confirmed by Western blot to reveal the potential molecular mechanisms by which NRP1 promotes the malignant progression of BC. Results Overexpression of NRP1 was observed in several human BC cell lines. NRP1 knockdown inhibited cell proliferation, promoted apoptosis, and decreased angiogenesis, migration, and invasion in T24 and 5637 human BC cells. Microarray analysis results indicated that the expression of NRP1 was correlated with the levels of cyclin dependent kinase (CDK) 4, baculoviral IAP repeat containing 3, Cyclin E 2, CDK2, and AP-1 transcription factor subunit in BC. We also demonstrated that the biological function of NRP1was associated with activation of the mitogen-activated protein kinase (MAPK) signalling pathway. Conclusions Our findings provide evidence that NRP1, as a potential tumour promoter, contributes to the metastasis and invasion of BC, which is associated with the activation of the MAPK pathway. Targeting NRP1 has the potential to become a new therapeutic strategy to benefit more patients with BC or other cancers.