Fig. 2

The anti-apoptotic Mcl-1 protein and hypoxic cell viability. a Expression of Mcl-1 in a panel of human colorectal carcinoma cell lines, as illustrated by Western blot analysis. The experiment was performed twice. b Three parental cell lines were treated with short hairpin (sh)RNA of Mcl-1 and a non-target control sequence (shc002v), and expression of anti-apoptotic proteins was examined by Western blot analysis. The experiment was performed at least three times for each of the cell line groups. c The parental and the shc002v and shMcl-1 versions of the three cell lines were treated for 24 h with ABT-737 (inhibitor of anti-apoptotic Bcl-2 family proteins; 10 μM), AZD8055 (mTOR inhibitor; 10 μM), or combo-Rx (10 μM of both compounds in combination) under hypoxic conditions. Cell viability (measured by the MTS assay) values for treated cells relative to the corresponding controls (mean ± SD) are shown. Statistically significant differences between cell line versions are indicated (asterisk, p < 0.05; cross, p < 0.01). d The same cell line entities were treated for 24 h under hypoxic conditions with ABT-737, AZD8055, or combo-Rx alone or following pre-treatment for 45 min with the pan-caspase inhibitor Z-VAD (20 μM), as indicated. Cell viability values relative to the corresponding control values are shown as mean ± SD. Statistically significant differences between treatment groups are indicated (asterisk, p < 0.05; cross, p < 0.01)