A- LBW242 potentiates the proapoptotic effect of Topotecan Hydrochloride, a topoisomerase I inhibitor. A2780WT PINCO and FLIP (top panels) and SKOV3 PINCO and FLIP (bottom panels) cells have been incubated for 24 h either in the absence (Control) or in the presence of either DMSO 0.01% or zVAD-fmk 40 μM, Topotecan Hydrochloride 1 μM, TRAIL 50 ng/ml or LBW242+zVAD-fmk, LBW242+Topotecan Hydrochloride, TRAIL+zVAD-fmk, TRAIL+Topotecan Hydrochloride, Topotecan Hydrochloride +zVAD-fmk, LBW242+TRAIL, LBW242+TRAIL+zVAD-fmk, LBW242+Topotecan Hydrochloride+zVAD-fmk and analysed for induction of apoptosis by flow cytometry. The data represent the mean values ±SEM observed in three separate experiments. In A7280 WT PINCO and in SKOV3 PINCO cells LBW242+TOPO induced a proportion of dead cells higher than that observed with either LBW242 (p = <0.05) or TOPO (p = <0.05). B and C – Evaluation of caspases-8 activation in A2780 and A2780ADR cells incubated either in the absence (Control) or in the presence of LBW242 or of Topotecan or of both LBW242 and Topotecan. Caspase-8 activity in intact cells was measured using a caspases-8 specific fluorigenic substrate. Original results from one representative analysis are reported in B, while the mean values±SEM of the percentages of cells displaying caspase-8 activation are reported in C. The percentage of cells exhibiting activated caspases-8 was higher both for WT and ADR cells in LBW242 than in NT cells (p = <0.05) and in LBW242+TOPO than in LBW242 or TOPO-treated cells (p = <0.05).