Effects of the proapoptotic regulator Bcl-2/adenovirus EIB 19-kDa-interacting protein 3 on the chemosensitivity of human colon cancer cell lines.

In the clinical setting, drug resistance remains a significant obstacle for successful chemotherapy. Bcl-2/adenovirus EIB 19-kDa-interacting protein 3 (BNIP3) is a proapoptotic member of the Bcl-2 family. To address its potential as a therapeutic target for chemosensitisation, this study investigated the effect of BNIP3 expression on chemosensitivity and reversal of oxaliplatin (L-OHP) resistance in human colon cancer cell lines. A plasmid expressing the BNIP3 gene was transfected into human parental colon cancer cell lines (SW620 and colo320) and L-OHP-resistant colon cancer cell lines (SW620/L-OHP and colo320/L-OHP) using Lipofectamine™ 2000, and the transfection efficiency was determined using fluorescence optics. Western blot analysis identified that SW620/L-OHP and colo320/L-OHP cells expressed lower levels of BNIP3 protein compared with the SW620 and colo320 cells. Transfection with the recombinant BNIP3 plasmid revealed an increase in BNIP3 expression in tumour cells. Following transfection with pDsRed-BNIP3, the chemosensitivity of parental and L-OHP-resistant cell lines to L-OHP was increased (P<0.01), as detected by the Cell Counting Kit-8 (CCK8) assay. Hoechst 33342 staining and flow cytometry revealed that the effects on L-OHP-induced apoptosis were enhanced by the overexpression of BNIP3. Chemosensitisation in human colon cancer cells was observed following treatment with the recombinant BNIP3 plasmid in vitro. The results of this study suggest that BNIP3 is a potential therapeutic target for reversing the resistance of L-OHP-resistant colon cancer cells to L-OHP.