Fig 2: Effect of NNT loss on redox homeostasis. (A) mRNA Nnt levels in the three mouse strains. (B) No NNT protein expression was observed in Nnt-/- (Western blot) however there was a two-fold upregulation in NntBAC when compared to Nnt+/+. (C) Protein levels of TXNRD2, PRDX3 and GPX1 in the Nnt+/+, Nnt-/- and NntBAC mouse adrenals were normalised to actin with representative Western blots shown to the right.

Fig 3: t-BHP exposure induced oxidative stress damage in HEI-OC1 cells. (A) HEI-OC1 cells were treated with gradient concentrations of t-BHP from 0 to 200 µM for 4 h. Cell viability was then determined CCK8 assays. (B) ROS levels of HEI-OC1 cells after treatment with 80 µM t-BHP for 4 h in comparison with controls. FITC fluorescence from a DCFH-DA probe was measured by flow cytometry. (C) Western blots showing the expression levels of ROS scavenging enzymes in HEI-OC1 cells treated with or without t-BHP. ß-Tubulin was used as an internal reference. (D) RT-qPCR analysis of the genes encoding ROS scavenging enzymes in t-BHP treated HEI-OC1 cells relative to controls. Tubb3 was used as an internal reference. (E) The enzymic activity of SOD in t-BHP-treated HEI-OC1 cells relative to controls, as determined by colorimetric analysis. (F) The enzymic activity of GPx in t-BHP-treated HEI-OC1 cells relative to controls, as determined by colorimetric analysis. (G) The enzymic activity of catalase in t-BHP-treated HEI-OC1 cells relative to controls, as determined by colorimetric analysis. Statistical results relate to mean MFI ± SEM. Data are represented as mean ± SEM. Bar charts were compared by the Student’s t-test or ANOVA (ns = not significant, *p < 0.05, **p < 0.01, and ***p < 0.001).

Fig 4: The urinary 8-oxo-dGuo levels (a) and plasma antioxidant defense status [CAT (b), GPx (c), NQO1 (d), and total SOD (e) activities and GSH levels (f)] in control subjects and BCC patients before and after surgery. Values given are mean ± SD. The statistical significance of differences between the control and case was evaluated by one-way ANOVA followed by Tukey's post hoc test. *** P < 0.001 compared to preoperative values in control subjects prior to surgery; ### P < 0.001 compared to preoperative values in BCC patients prior to surgery. Principal component analysis was performed to systematically investigate similarity of DNA damage and antioxidant defense parameters from different groups of patients (g). Factor analysis is overlaid on top of the patient scores, both before surgery (case: triangle; control: square) and 1 month after surgery (case: circle; control: plus). The dashed and dotted ovals delineate the approximated distribution of each group with 95% confidence intervals.

Fig 5: The H&E staining ((a)–(c)) and IHC staining for oxidative DNA damage, 8-oxo-dGuo ((d)–(g)), DNA repair enzyme, hOGG1 ((h)–(k)), and antioxidant proteins, CAT ((l)–(o)), GCLC ((p)–(s)), GPx ((t)–(w)), Nrf2 ((x)–(aa)), and MnSOD ((ab)–(ae)), in control subjects and tumor and nontumor lesions of BCC patients. Values given are mean ± SD. The statistical significance of differences between the control and case and between adjacent epidermis and tumor lesions of BCC patients was evaluated by nonparametric variables with Kruskal-Wallis test followed by Dunnett's post hoc test. ∗ P < 0.05, ∗∗ P < 0.01, ∗∗∗ P < 0.001 compared to control; ## P < 0.01, ### P < 0.001 compared to tumor lesions of BCC patients.