American Society of Hematology

Figure 1.

$Figure 1. Blockade of p53-MDM2 interaction inhibits the growth of cell lines with wild-type p53 through cell-cycle arrest and apoptosis induction. (A) Time course of effects induced in OCI-AML-3 and MOLM-13 cells by Nutlin-3a (active enantiomer) and -3b (less active enantiomer) on viable cell number. The cells were incubated with a range of concentrations of Nutlin-3a (1 μM, ▪; 5 μM, •; 10 μM, ▴) or -3b (1 μM, □; 5 μM, ○; 10 μM, ▵), and the cell viability was determined by trypan blue exclusion method. Results are expressed as the percentage of the viable cell number in an untreated group, and represent the average of triplicate cultures. (B) AML cell lines with wild-type p53 (OCI-AML-3 and MOLM-13) or mutant p53 (HL-60 and NB4) cells were incubated with the indicated concentrations of Nutlin-3a or -3b for 72 hours and the cell viability was determined by trypan blue exclusion method. MDM2 inhibitor showed significant cytotoxic activity in OCI-AML-3 and MOLM-13 cells. Results are expressed as the mean plus or minus the standard deviation (SD). *P < .05. (C) Nutlin-3a causes cell-cycle arrest in leukemia cells with wild-type p53. OCI-AML-3 (○), MOLM-13 (□), HL-60 (•), and NB4 (▪) cells were cultured for 12 hours in the presence of Nutlin-3a at the indicated concentrations, and stained for DNA content. Cell-cycle distribution was analyzed using ModFit LT software. Results are expressed as percentage of S-phase cells in DMSO-treated group. Nutlin-3a at 2.5 μM induced almost maximal cell-cycle arrest in both OCI-AML-3 and MOLM-13 cells. Results are representative of 3 independent experiments. (D) Cells were incubated with the indicated concentrations of Nutlin-3a or -3b for 48 hours (24 hours for MOLM-13 cells), and the annexin V–positive fractions were measured by flow cytometry. □ represents untreated controls. Results are expressed as mean ± SD.$

Blockade of p53-MDM2 interaction inhibits the growth of cell lines with wild-type p53 through cell-cycle arrest and apoptosis induction. (A) Time course of effects induced in OCI-AML-3 and MOLM-13 cells by Nutlin-3a (active enantiomer) and -3b (less active enantiomer) on viable cell number. The cells were incubated with a range of concentrations of Nutlin-3a (1 μM, ▪; 5 μM, •; 10 μM, ▴) or -3b (1 μM, □; 5 μM, ○; 10 μM, ▵), and the cell viability was determined by trypan blue exclusion method. Results are expressed as the percentage of the viable cell number in an untreated group, and represent the average of triplicate cultures. (B) AML cell lines with wild-type p53 (OCI-AML-3 and MOLM-13) or mutant p53 (HL-60 and NB4) cells were incubated with the indicated concentrations of Nutlin-3a or -3b for 72 hours and the cell viability was determined by trypan blue exclusion method. MDM2 inhibitor showed significant cytotoxic activity in OCI-AML-3 and MOLM-13 cells. Results are expressed as the mean plus or minus the standard deviation (SD). *P < .05. (C) Nutlin-3a causes cell-cycle arrest in leukemia cells with wild-type p53. OCI-AML-3 (○), MOLM-13 (□), HL-60 (•), and NB4 (▪) cells were cultured for 12 hours in the presence of Nutlin-3a at the indicated concentrations, and stained for DNA content. Cell-cycle distribution was analyzed using ModFit LT software. Results are expressed as percentage of S-phase cells in DMSO-treated group. Nutlin-3a at 2.5 μM induced almost maximal cell-cycle arrest in both OCI-AML-3 and MOLM-13 cells. Results are representative of 3 independent experiments. (D) Cells were incubated with the indicated concentrations of Nutlin-3a or -3b for 48 hours (24 hours for MOLM-13 cells), and the annexin V–positive fractions were measured by flow cytometry. □ represents untreated controls. Results are expressed as mean ± SD.

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