Figure 6.

AZD7762 abrogates A-macB-induced G2/M arrest and enhances apoptosis triggered by A-macB. (A-C) The Chk1/2-specific inhibitor AZD7762 abrogated the G2/M arrest induced by A-macB. NSCLC cells were treated with AZD7762 (100 nM) or DMSO (vehicle) for 2 h prior to exposure to 1 μM A-macB. The cell cycle distribution was detected by flow cytometry. (D) The function of Chk1/2 was suppressed by AZD7762, leading to Cdc25C hyperactivity and decreased Cdc2/cyclin B dephosphorylation; this enabled the cells to enter mitosis with DNA damage, resulting in mitotic catastrophe, a phenomenon reflected by the levels of γH2AX, p-hH3 and cleaved caspase 3. (E and F) Enhanced cytotoxic effect of AZD7762 to A-macB. H1299 and A549 cells were pretreated with or without 100 nM AZD7762 for 2 h. Then the cells were incubated with 0.1% DMSO, 100 nM AZD7762, A-macB, or A-macB+AZD7762 for 24 h, respectively. A-macB was administered at a non-cytotoxic concentration (1 μM). The apoptotic status of the cells was examined by flow cytometry. Data are presented as the mean ± SEM (*p < 0.05, **p < 0.01, ***p < 0.001).