Figure 1

Combinational treatment of ovarian cancer cell lines with TM and doxorubicin reduces cell viability via promotion of apoptotic signaling. SKOV-3 (a) or A2780 (b) ovarian cancer cells were treated with TM (0, 30 μM for SKOV-3; 0, 7.5 μM for A2780) for 24 h, after which the cells were treated with doxorubicin (0, 2.5, 5, 10 μM) for another 24 h. Cell viability was evaluated as described in Methods. Data are expressed as the mean of the triplicate determinations (X ± SD) compared to untreated cells [100%]. (c) SKOV-3 cells were treated with TM (0, 30 μM) for 24 h, after which the cells were treated with doxorubicin (0, 5 μM) for another 24 h. The change in the mitochondrial membrane potential (ΔΨ_m) was measured by flow cytometry. Intact cells = Q4, Loss of ΔΨ_m = Q3, ruptured cell membrane = Q1 and Q2. (d) SKOV-3 cells (left panel) were treated with TM (0, 30 μM) for 24 h, after which the cells were treated with doxorubicin (0, 5 μM) for 1, 4, 7 or 24 h as indicated. The same procedure was employed to treat A2780 cells (right panel) with different concentrations of TM (0, 7.5 μM) and doxorubicin (0, 2.5 μM). Immunoblotting was carried out with primary antibodies against cleaved PARP, caspase-3, and -7. As an internal standard for equal loading blots were probed with an anti-GAPDH antibody.