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. 2009 Mar 10;100(6):1128–1136. doi: 10.1111/j.1349-7006.2009.01150.x

Figure 2.

Figure 2

Cyclin‐dependent kinase (CDK) 1 enhances p53‐mediated apoptosis in AML cells. (a) AML cells were incubated with the indicated concentrations of RO‐3306 or Nutlin‐3 for 18 h, and the Annexin V‐positive fractions were measured by flow cytometry. Results are expressed as mean ± SD. RO‐3306 enhanced Nutlin‐induced apoptosis in p53 wild‐type OCI‐AML‐3 and MOLM‐13 cells but not in mutant p53 HL‐60 cells. (b) Combination index plots as mean values ± 2SD generated using CalcuSyn software (crosses represent actual data points for the RO‐3306 and Nutlin‐3 combination). Combination index values of less than 1.0 indicate synergism. (c) Cell cycle‐independent synergistic apoptosis induction by the RO‐3306 and Nutlin‐3 combination. MOLM‐13 cells were treated for 8 h with 5 µM RO‐3306 or 2.5 µM Nutlin‐3. The Annexin V‐positive fractions in correlation with DNA content were measured by flow cytometry. Data were gated on the FL2‐area versus FL2‐width cytogram to exclude doublets. Cells were gated on dot plots (middle row), based on Annexin staining. The Annexin‐V‐positive fraction (AnV+) corresponds to apoptotic cells, whereas the Annexin‐V‐negative fraction (AnV−) corresponds to viable cells. Histograms indicate the distribution of DNA content in the gated populations (AnV+, upper row; AnV−, lower row) of the preceding dot plots.