A, A2780 cells were subjected to cell-cycle analysis without or with 2 μM cisplatin, and sub-G1 cell populations were measured. Similarly, A2780 cells were treated with non-targeted siRNA (NT siRNA) or HMGB3 siRNA and 2 μM cisplatin. Cisplatin treatment increased the apoptotic population of the A2780 cells, but no significant difference was observed as a function of HMGB3 depletion. B, A2780/CP70 cells were subjected to cell-cycle analysis treated without or with 2 μM cisplatin and the sub-G1 cell populations were measured. As described above, A2780/CP70 cells were treated with NT siRNA or HMGB3 siRNA and then treated with 2 μM cisplatin. HMGB3 depletion increased the apoptotic population of the A2780/CP70 cells after 2 μM cisplatin treatment. The sub-G1 and the G1 values presented as insets are an average of three measurements from three independent experiments. CP = cisplatin.