Figure 2. ZEB1 attenuates UVA-induced senescence in HDFs via DNMT1. (A) ZEB1 and DNMT1 expression in HDFs at the mRNA (a, b) and protein (c, d) levels following ZEB1 over-expression or knockdown, as determined by real-time PCR and Western blotting, respectively (n = 3).* vs ZEB1-vector or negative control (NC)-siRNA, P< 0.05. (B) Western blots images (upper panels) and quantitative analysis (lower panels), representative of three independent experiments, were showing p53, p21, and p16 protein expression. (C) Senescence-associated β-galactosidase(SA-β-gal) activity of cells under the indicated conditions. Representative images are shown (scale bar = 200 µm). The percentages of SA-β-galpositive cells under each condition are presented as the mean ± standard deviation of three independent experiments. * vs ZEB1-vector or NC-siRNA, P < 0.05;# vs ZEB1-vector+UVA or NC-siRNA+UVA, P < 0.05. (D) Western blots images (left panels) and quantitative analysis (right panels), representative of three independent experiments, showing p53, p21, and p16 protein expression in HDFs co-transfected with ZEB1-cDNA and DNMT1-shRNA. (E) SA-β-gal activity of cells under the indicated conditions, following DNMT1 knockdown. Cells were analyzed as described in (C). * vs ZEB1-vector, P < 0.05;# vs ZEB1-vector+UVA, P < 0.05; $ vs ZEB1-cDNA+UVA.