Knockdown of the nucleosome binding protein 1 inhibits the growth and invasion of clear cell renal cell carcinoma cells in vitro and in vivo

NSBP1 expression was detected in renal tissues from 152 ccRCC patients by immunohistochemistry, and examined in ccRCC cell lines by RT-PCR and Western blot analysis. ccRCC cells were transfected by NSBP1 RNAi and cell viability, apoptosis and invasion were detected by cell vitality test, flow cytometry and transwell assay in vitro. Xenograft in nude mice was also employed to examine the tumorigenesis of ccRCC cells depleted of NSBP1.Immunohistostaining showed strong immunoreactivity of NSBP1 in all ccRCC tissues and NSBP1 expression level was associated with tumor grade (p = 0.04). NSBP1 expression at mRNA and protein levels was high in ccRCC cell lines. Knockdown of NSBP1 induced cell cycle arrest and apoptosis, and inhibited invasion in 786-O cells. Western blot analysis demonstrated increased expression of Bax and decreased expression of Bcl-2, CyclinB1, VEGF, VEGFR-2, MMP-2, MMP-9, c-fos and c-jun in 786-O cells depleted of NSBP1. In vivo study further showed that knockdown of NSBP1 affected the tumorigenesis of ccRCC cells in nude mice.NSBP1 plays oncogenic role in ccRCCs by promoting cell proliferation and invasion, and could be exploited as a target for ccRCC treatment.Renal carcinoma is the 13th most common cancer worldwide, with clear cell and clear cell renal cell carcinoma (ccRCC) accounting for most of the renal cell carcinoma (RCC) [1]. Radical nephrectomy is effective to cure early and local ccRCCs, but advanced or metastatic ccRCCs barely respond to chemotherapy or radiotherapy and have poor prognosis. Therefore, it is important to better understand the pathogenesis of aggressive RCC in order to develop effective strategies for the prevention and treatment of RCC.NSBP1 is a new member of the high mobility group N (HMGN) protein family that modulates the structure and function of chromatin and plays an important role in transcription, histone modifications, DNA replication and DNA repair in living cells[2]. Early study showed that nucleosome binding pr