NRP-1 silencing suppresses hepatocellular carcinoma cell growth in vitro and in vivo

Neuropilin-1 (NRP-1) is a novel receptor of vascular endothelial growth factor 165 that promotes angiogenesis, tumor growth, tumor invasion and metastasis. However, its role in tumorigenesis and progression of human hepatocellular carcinoma (HCC) is unknown. In this study, lentivirus-mediated short hairpin RNA (shRNA) was used to silence NRP-1 in the HCCLM6 cell line to explore its role in regulating the growth of HCC. Recombinant NRP-1 shRNA lentivirus was prepared and transfected into HCCLM6 cells. Transfection efficiencies of the lentivirus were observed by flow cytometry. Protein and mRNA expression of NRP-1 were examined by western blot analysis and quantitative reverse transcription-polymerase chain reaction (RT-PCR), and the effect of the lentivirus on cell growth was determined using MTT assay. Different cell groups were inoculated into nude mice to establish cancer xenografts, and tumor growth was monitored. Protein expression of NRP-1 in tumor tissues was detected by western blot assay. Microvessel density (MVD) in tumor tissues was assessed by immunohistochemistry (IHC). Lentivirus-mediated shRNA efficiently reduced endogenous NRP-1 expression in HCCLM6 cells and significantly inhibited cell growth in vitro. In vivo, NRP-1 knockdown in tumor tissues resulted in decreased vasculature. NRP-1 promotes the growth of HCC in vitro and in vivo, and therefore may be considered as a novel therapeutic target for HCC.