Overexpression of the BRIP1 ameliorates chemosensitivity to cisplatin by inhibiting Rac1 GTPase activity in cervical carcinoma HeLa cells.

BRCA1-interacting protein 1 (BRIP1), a DNA-dependent ATPase and a DNA helicase, is critical for BRCA-associated DNA damage repair functions and may be associated with the tumourigenesis and aggressiveness of various cancers. Here, we constructed a BRIP1 recombinant plasmid, overexpressed it in a cervical cancer cell line (HeLa) and found that ectopic expression of BRIP1 could remarkably enhance the antitumor activity of cisplatin, as demonstrated by decreased cell viability, colony formation and tumour xenografts' weight. Moreover, BRIP1 promoted cisplatin-mediated cell apoptosis and suppressed tumour angiogenesis. We also found that the synergistic inhibition effect of BRIP1 might be partially attributed to attenuation of Rac1 GTPase activation and that Rac1 GTPase re-activation could reverse the sensitizing effect induced by BRIP1. Our study suggested that up-regulation of BRIP1 could enhance chemosensitivity of HeLa cells to cisplatin through inhibiting Rac1 GTPase activation, and it provides a new insight into the essential role of BRIP1 in cervical cancer chemotherapy.