Research Paper Volume 8, Issue 7 pp 1442—1456

Figure 5. The overexpression of miR-638 in K562 cells impedes DNA damage repair ability and increases the cellular sensitivity to cisplatin. (A) K562 cells were transfected with negative control mimics (mimics-NC) or miR-638 mimics (mimics-638). Levels of miR-638 in the transfected cells were measured by qRT-PCR, and the levels of SMC1A and BRCA1 mRNA and protein were detected by qRT-PCR and western blotting, respectively. Each group of comparative qRT-PCR contained three duplicates, and the results were normalized to Snord44 snRNA. HSC70 served as the loading control. (B) K562 cells were transfected with mimics-NC or mimics-638, after which they were treated with cisplatin (5 μM) for 18 h. DNA damage was then measured by the comet assay. Representative blots are shown. The comet tail moment was counted, and 50 cells were analyzed in each group. (C) K562 cells were transfected with mimics-NC or mimics-638 and then re-plated in 96-well plates. Afterwards, they were treated with cisplatin (0 or 50 μM), which was dissolved in RPMI-1640 medium, for 48 h, and the relative cell viability was measured by the CCK8 assay. Data are presented as a column chart. NS: not significant, **: p<0.01, ***: p<0.001, #: p<0.0001, compared to control with the Student's t test. Error bars, S.D.