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M. Boudny et al.
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Figure 3. Effects of MU380 (single-agent) on leukemia and lymphoma cell lines. (A) Cell viability was reduced similarly in the TP53-wt and TP53-mutated cell lines (P=0.257) after 72 hours (h) treatment. (B) Distribution of IC50 values in leukemia and lymphoma cell lines (P=0.004). (C) MU380 (400 nM; 24 h) significantly changed the cell cycle profile in MEC-1 (P<0.001), MEC-2 (P=0.010) and OSU-CLL (P<0.001) cell lines; the other three cell lines showed insignificant differences. (D) MEC-1 cells treated with MU380 (400 nM; 24 h) exhibited significantly reduced DNA synthesis rate compared to control untreated cells (lower EdU incorporation, P=0.001) and consequently manifested extensive apoptosis as evidenced by the PARP protein cleavage (P=0.001). The cell death was also confirmed using labeling with Live/Dead Red agent (P=0.002). Graph summarizes results of three independent experiments. (E) MU380 (400 nM; 48 h) elicited apoptosis in all tested cell lines as evidenced through the cleaved PARP (C-PARP) and caspase-3 (C-Caspase-3) proteins. Note: the cell lines were exposed individually on UVITEC detection instrument; hence, intensity of the bands among the cell lines cannot be mutually compared. (F) The time-dependent γH2AX accumulation reflects gradually increas- ing RS after treatment with MU380 (400 nM); the cells were harvested at indicated time points. (G) MU380 (400 nM; 24 h) does not change the p53 protein level in p53-wt NALM-6 cell line, in contrast to fludarabine (2.7 μM; positive control). (H) MU380 (400 nM; 24 h) induces negligible expression of p53 target genes BAX, PUMA, GADD45A, and CDKN1A (p21), in contrast to fludarabine (2.7 μM; positive control). The fold change is related to the untreated control (CTR). The graph sum- marizes results of two independent real-time polymerase chain reaction analyses. Error bars represent standard deviation. **P<0.01; ***P<0.001.
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