Figure 4

Mitotic arrest induced by DT-13 and NVB was required for apoptosis induction. (a) NCI-H460 and A549 cells were treated with 10 μM DT-13 and 0.01 μM NVB for 48 h, and the expression of cyclin B1 was determined by western blotting analysis. (b) NCI-H460 and A549 cells were pretreated with 5 μM CDK1 inhibitor RO-3306 for 2 h, and cells were then exposed to 10 μM DT-13 and 0.01 μM NVB for another 12 h. Expression of mitotic marker MPM2 was observed by western blotting, and β-actin was served as the loading control. (c) Cells were treated with 10 μM DT-13 and 0.01 μM NVB for 48 h after pretreatment of 5 μM RO-3306 for 2 h, and apoptotic cells were determined by Annexin V/PI staining. (d) The percentage of apoptotic cells (including early and late apoptotic cells) was shown in the histograms, and the data were expressed as mean±S.D. in triplicate using Student’s t-test (two-tailed). **P<0.01