a, The sequence of p53 gene (exons 5–9) in HaCaT and HaCaT-T cells was detected by sequencing. b-d, The mRNA (b) and protein (c) levels and activity (d) of p53 in HaCaT and HaCaT-T cells after the indicated treatments. Representative images of western blotting (c, up). e-g, The mRNA levels of three p53 specific target genes including CDKNA1 (e), RRM2B (f), and SUSD6 (g) were examined by RT-qPCR. For b-g, At least 3 biological replicates, error bars indicate mean ± SEM. The P-values were determined by two-tailed t-test. “*” indicates a significant difference compared to control group (P < 0.05).