Abstract
Overexposure to ultraviolet radiation and environmental carcinogens drive skin cancer development through redox imbalance and gene mutation. Antioxidants such as triterpenoids have exhibited anti-oxidative and anti-inflammatory potentials to alleviate skin carcinogenesis. This study investigated the methylome and transcriptome altered by tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) or TPA with 2-cyano 2,3-dioxoolean-1,9-dien-28-oic acid (CDDO). The results show that CDDO blocks TPA-induced transformation dose dependently. Several differential expressed genes (DEGs) involved in skin cell transformation, while counteracted by CDDO, were revealed by differential expression analysis including Lyl1, Lad1, and Dennd2d. In CpG methylomic profiles, the differentially methylated regions (DMRs) in the promoter region altered by TPA while showing the opposite methylation status in the CDDO treatment group were identified. The correlation between DNA methylation and RNA expression has been established and DMRs showing inverse correlation were further studied as potential therapeutic targets. From the CpG methylome and transcriptome results, CDDO significantly restored gene expression of NAD(P)H:quinone oxidoreductase 1 (Nqo1) inhibited by TPA by decreasing their promoter CpG methylation. Ingenuity Pathways Analysis (IPA) shows that CDDO neutralized the effect of TPA through modulating cell cycles, cell migration, and inflammatory and immune response regulatory pathways. Notably, Tumor Necrosis Factor Receptor 2 (TNFR2) signaling was significantly downregulated by CDDO potentially contributing to prevention of TPA-induced cell transformation. Overall, incorporating the transcriptome, CpG methylome, and signaling pathway network, we reveal potential therapeutic targets and pathways by which CDDO could reverse TPA-induced carcinogenesis. The results could be useful for future human study and targets development for skin cancer.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
