Fig. 2: Low dose UVA irradiation caused increased p53 protein levels and enhanced phosphorylation and MDM2 mRNA expression in HCT-treated skin biopsies independent of γH2A.X.

A Representative Western blots demonstrating protein level of tumor suppressor protein p53, phosphorylation of histone H2A.X (γH2A.X, Serin139) and phosphorylation of p53 (Serin15) in untreated control biopsies (Ctrl), and in biopsies treated with HCT 6 h after irradiation with 300 mJ/cm² UVA or UVB. Unirradiated biopsies served as group-specific control (non). Protein expression of Glyceraldehyde 3-Phosphate Dehydrogenase (GAPDH) served as loading control. Quantification of (B) p53 protein (C) phospho-p53, and (D) γH2A.X. E Gene expression of p53-regulator MDM2 normalized against GAPDH 6 h after irradiation. F Representative Western blots of p53, γH2A.X and phospho-p53 (Serin15) in untreated control biopsies (Ctrl), and in biopsies treated with HCT 24 h after irradiation with 300 mJ/cm² UVA or UVB. Unirradiated biopsies served as group-specific control (non). Protein expression of GAPDH served as loading control. Quantification of (G) p53 protein (H) phospho-p53, and (I) γH2A.X. J Gene expression of MDM2 normalized against GAPDH 24 h after irradiation. For (B, C, D, E, G, H, I, J) n = 6 biopsies per group. Data are shown as mean ± SEM with individual points. For comparison of three groups, P-value was determined using Kruskal-Wallis with Dunn´s multiple comparisons test for Ctrl group in (B, C, D, G, H, I) and One-way ANOVA with Tukey multiple comparisons test for HCT group in (B, C, D, G, H, I). For (E and J) One-way ANOVA with Tukey multiple comparisons test was used. An unpaired student t-test (#) was used for comparison of 2 groups for (B, C, E, G, H, J). IOD: Integrated optical density. Numerical source data are provided within the Supplementary Data 1 file.