CIAPIN1 gene silencing enhances chemosensitivity in a drug-resistant animal model in vivo

Overexpression of cytokine-induced apoptosis inhibitor 1 (CIAPIN1) contributes tomultidrug resistance (MDR) in breast cancer. This study aimed to evaluate thepotential of CIAPIN1 gene silencing by RNA interference (RNAi) as atreatment for drug-resistant breast cancer and to investigate the effect ofCIAPIN1 on the drug resistance of breast cancer invivo. We used lentivirus-vector-based RNAi to knock downCIAPIN1 in nude mice bearing MDR breast cancer tumors and foundthat lentivirus-vector-mediated silencing of CIAPIN1 couldefficiently and significantly inhibit tumor growth when combined with chemotherapyin vivo. Furthermore, Western blot analysis showed that bothCIAPIN1 and P-glycoprotein expression were efficiently downregulated, and P53 wasupregulated, after RNAi. Therefore, we concluded that lentivirus-vector-mediated RNAitargeting of CIAPIN1 is a potential approach to reverse MDR ofbreast cancer. In addition, CIAPIN1 may participate in MDR of breastcancer by regulating P-glycoprotein and P53 expression.