Bcl-xL and Myeloid cell leukaemia-1 contribute to apoptosis resistance of colorectal cancer cells

Figure 4 Modulation of Mcl-1 expression alters chemotherapeutic drug-induced apoptosis. A: SW480 cells were transfected with siRNA specific for Mcl-1, or transfected with siRNA specific for GFP as control (20 nmol/L). After the indicated time post transfection, total RNA was extracted and analyzed for Mcl-1 expression by quantitative real-time PCR (left panel). Relative expression was calculated as described in the materials and methods section. In addition, after the indicated time post transfection, cells were lyzed and analyzed for Mcl-1 expression by Western blot (right panel). α-Tubulin expression was used to control equal loading; B: SW480 cells were transfected with siRNA specific for Mcl-1 or transfected with control siRNA. 24 h post transfection cells were treated with 5-FU (10 &mgr;g/mL), oxaliplatin (16 &mgr;g/mL) and irinotecan (60 &mgr;g/mL) for further 24 h. Apoptosis induction was measured by flow cytometry (left panel) and MTT assay (right panel). Values are mean ± SD, ^aP < 0.05.