Figure 4

Effect of inhibition of caspase -3, -7, -8 and -9 expression on cell growth and survival of SK -BR- 3 and MCF- 7 cells after paclitaxel and SB -T- 1216 application. (A) Efficiency of caspase suppression based on specific siRNAs in SK-BR-3 and MCF-7 cells is shown. Levels of caspases were determined using western blot analysis and relevant antibodies (see “Materials and methods”). Actin levels were used to confirm equal protein loading. (B) The effect of specific caspase siRNAs on the growth and survival of SK-BR-3 and MCF-7 cells after taxane treatment (100 nM for SK-BR-3 cells and 300 nM for MCF-7 cells) is presented. The cells were seeded at 20 × 10³ cells/100 μl of medium per well and prepared as described (see “Materials and methods”). After 48 and 96 h of incubation, the number of living cells was determined (see “Materials and methods”). Each column represents the mean of 3 or 4 separate cultures ± SEM. *P < 0.05, **P < 0.01 when comparing the number of living cells in cultures with individual specific siRNAs and culture with no siRNA.