The effect of ABT-199, ABT-263 or ABT-263 in combination with paclitaxel on LNCaP or PC3 cells.

<p>(A) ABT-263, but not ABT-199, could effectively trigger PARP degradation in LNCaP and PC3 cells in a dose-dependent manner, but it could only activate caspase 3 to a detectable level in LNCaP cells. Immunoblot analysis of cell lysates from LNCaP or PC3 cells treated by ABT-199 or ABT-263 alone for 48 hr at various concentrations were assayed as indicated. Caspase 3(a): the activated form of caspase 3. Caspase 7(a): the activation form of caspase 7. Experiments were repeated three times and representative results are shown. The readouts of caspase 3(a) normalized to GAPDH between LNCaP and PC3 cells treated with 5μM of ABT-263 are shown at the bottom. (**)statistical significance between two readouts. (B) The combination of 50 nM of paclitaxel with various concentrations of ABT-263 had a synergistic effect on apoptosis in both LNCaP and PC3 cells. The efficacy of ABT-263 in combination with paclitaxel in LNCaP cells was higher than in PC3 cells. Immunoblot analysis of cell lysates from LNCaP or PC3 cells treated by paclitaxel in combination with ABT-263 or ABT-263 alone for 48 hr at various concentrations were assayed as indicated. Caspase 3(a): the activated form of caspase 3. Caspase 7(a): the activation form of caspase 7. Experiments were repeated three times and representative results are shown. The respective readouts of caspase 3(a) normalized to internal control, α-tubulin or GAPDH in LNCaP or PC3 with LNCaP are shown at the bottom. (**) statistical significance between two readouts.