Research Paper Volume 11, Issue 16 pp 5992—6013

Figure 4. miR-663a promoted cellular senescence by targeting CDK4 and CDK6. (A) CCK-8 assays were used to detect the effect of miR-663a on HDF viability. Data are shown as the means ± standard errors of the means based on at least three independent experiments. (B) Flow cytometry depicted the percentages of apoptosis in HDFs transfected with miRNA mimics control and miR-663a mimics. (C) After miRNA inhibitor transfection for 48h, the cell cycle distribution of HDFs at 24 h post-UVB irradiation. (D) After cotransfection with siRNA and miRNA inhibitor for 48h, the cell cycle distribution of HDFs at 24 h post-UVB irradiation. (E) miR-663a negatively regulated the expression of CDK4 and CCND1, but positively regulated CDK6 at mRNA levels. (F) miR-663a negatively regulated the expression of Cdk4 and Cdk6 at protein levels, but had no effect on the expression of CyclinD1. (G) Putative binding site of miR-663a in the 3′-UTR of CDK4 and the sites of target mutagenesis are indicated. Luciferase activity in HDFs, demonstrating the effects of miR-663a on the expression of its target gene CDK4. (H) Putative binding site of miR-663a in the 3′-UTR of CDK6 and the sites of target mutagenesis are indicated. Luciferase activity in HDFs, demonstrating the effects of miR-663a on the expression of its target gene CDK6. Data are shown as the means ± standard errors of the means based on at least three independent experiments. P values were determined by Student’s t-tests. *P < 0.05; **P < 0.01; and ***P < 0.001.