p21 and p53 protein expression by western blotting. (A) Western blots of p21 and p53 expression with GAPDH as a reference standard. (B) p53 protein expression mirrored p21 protein expression. (C) As expected, p21 protein expression was significantly higher and lower in p21-overexpressing (p21+) and p21-silenced (p21–) cells, respectively. After UVB irradiation, p21 expression levels displayed the same trend but were significantly lower. * p<0.05 vs. CON, #
p<0.05 vs. p21+, @
p<0.05 vs. p21–, &
p<0.05 vs. UVB-CON.