Therapeutic targeting of survivin pathway in breast cancer cell types. (A) MCF-7 cells were incubated with the indicated increasing concentrations of doxorubicin (Doxo) alone or in combination with YM155 and analyzed for cell viability after 48 h. Data are representative of one experiment out of two independent determinations. (B) The indicated breast cancer cell types were incubated with vehicle (Veh, DMSO), Doxo or YM155, alone or in combination and analyzed for cell viability by Trypan blue exclusion after 48 h. (C) MCF-7 cells were treated with the various drug combinations as indicated and analyzed for hypodiploid DNA content (sub-G1), by propidium iodide and flow cytometry. For panels B and C, data are the mean ± SEM of replicates of a representative experiment out of two independent determinations. (D) MCF-7 cells treated as in B, C were analyzed by Western blotting. The positions of cleaved products for poly-ADP ribose polymerase (PARP) or caspase-3 are indicated.