Biotin-mediated epigenetic modifications: Potential defense against the carcinogenicity of benzo[a]pyrene.

Environmental pollution and an unhealthy lifestyle result in direct exposure to dangerous chemicals that can modify endogenous pathways and induce malignant transformation of human cells. Although the molecular mechanisms of tumorigenesis are still not well understood, epigenetic alteration may be associated with exogenous chemical-induced carcinogenicity. Given the association between nutrition and cancer, nutrient supplementation may reduce aberrant epigenetic modifications induced by chemicals, thus decreasing carcinogenesis. This paper provides an overview of the epigenetic events caused by benzo[a]pyrene, a procarcinogenic and environmental pollutant, and biotin, an essential water-soluble vitamin, and investigates potential connections between them. This paper also discusses the potential inhibitory effect of biotin-related epigenetic modifications on the carcinogenicity of benzo[a]pyrene. The effect of nutritional supplementation on tumorigenesis involving epigenetic modifications is also discussed.

[Differential gene expressions in cells with low-dose hydrogen peroxide-induced adaptive response: a study with FDDRT-PCR].

OBJECTIVE: To identify differentially expressed genes in human embryo lung fibroblasts MRC-5 with adaptive response induced by low concentration of hydrogen peroxide (H(2)O(2)) using fluorescent differential display-RT-PCR (FDDRT-PCR). METHODS: The dose-effect pattern of H2O2 toxicity was determined using MTT assay, and the dose of 0.088, 0.88, 8.8, 88 micro;mol/L was defined as the low concentration, and 1100 micromol/L as the high concentration. Adaptive response model was established in MRC-5 cells verified using LDH release and cell apoptosis analyses. Differentially expressed genes in the cells with exposure to different doses of H(2)O(2) were detected by FDDRT-PCR, and some of the differentially displayed genes were determined using real-time quantitative PCR. RESULTS: Cells challenged with high-concentration H(2)O(2) for 1 h after H(2)O(2) pretreatment at low concentrations for 24 h resulted in lessened toxic effect in comparison with direct high-concentration H(2)O(2) exposure. The adaptive response of the cells was most obvious with H(2)O(2) pretreatment at 0.88 micromol/L. Altogether 60 differentially expressed genes were detected with FDDRT-PCR in different treatment groups, and 5 of them were identified and verified, including 1 unknown gene and 4 known genes (bcl-2, EIF3S5, NDUFS4 and RPS10). CONCLUSION: According to the results of FDDRT-PCR, the genes bcl-2, EIF3S5, NDUFS4 and RPS10 can be involved in H(2)O(2)-induced adaptive response of the MRC-5 cells.