Bax inhibitor-1 mediates apoptosis-resistance in human nasopharyngeal carcinoma cells

• DOI: 10.1007/s11010-009-0198-y
• Publication Date: 2009-07-04T07:23:02Z
• Authors: Meihong Zhang; Xiangyong Li; Yuefei Zhang; Keyuan Zhou
• Keywords: 0303 health sciences; 03 medical and health sciences; Caspase 3; Cell Line, Tumor; Down-Regulation; Humans; Membrane Proteins; Apoptosis; Nasopharyngeal Neoplasms; RNA, Small Interfering; Apoptosis Regulatory Proteins; 3. Good health

Bax inhibitor-1 (BI-1), a newly identified apoptosis inhibitor, has recently been found to be overexpressed in several human carcinomas and its specific down-regulation by RNA interference (RNAi) could lead to cell death. The purpose of this study is to investigate the role of BI-1 in apoptosis-resistance and the underlying mechanisms in human nasopharyngeal carcinoma (NPC) cells. Our results showed that BI-1 was expressed in two different human NPC cell lines, CNE-2Z and CNE-1, and specific inhibition of BI-1 expression by siRNA caused a significant increase in spontaneous apoptosis in both cell lines. Mechanistically, we demonstrated that down-regulation of BI-1 protein expression decreased the ratio of Bcl-X(L)/Bcl-2 with Bax protein as determined by Western blot and increased the activity of caspase-3 by colorimetric analysis, thus leading to the activation of the associated cell death pathways. Taken together, these results have provided evidence that BI-1 could serve as an important molecular target gene for the development of new therapeutic strategy against human NPCs.