Molecular alterations in hepatocarcinogenesis induced by dietary methyl deficiency.
ABSTRACT A chronic deficiency of major dietary methyl group donors--methionine, choline, folic acid, and vitamin B12--can induce the development of liver cancer in rodents. Feeding methyl-deficient diets causes several molecular alterations, including altered lipid metabolism, oxidative stress, deregulated one-carbon metabolism, and a number of epigenetic abnormalities that result in progressive liver injury culminating in the development of primary liver tumors. Importantly, this methyl-deficient model of endogenous hepatocarcinogenesis is one of the most relevant models of human liver carcinogenesis that allows studying liver cancer pathogenesis by substantially complementing many shortcomings of humans-only studies. In this review, we describe molecular changes and their role in pathogenesis of liver carcinogenesis induced by methyl deficiency.
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ABSTRACT: The association between oxidative stress and coronary artery disease (CAD) is well documented. However, the role of epigenetic factors contributing to oxidative stress is relatively unexplored. In this study, we aimed to explore the impact of DNA methylation profile in BCL2/E1B adenovirus interacting protein 3 (BNIP3), extracellular superoxide dismutase (EC-SOD) and glutathione-S-transferase P1 (GSTP1) on the oxidative stress in CAD. Further, the contribution of folate pathway genetic polymorphisms in regulating epigenome was elucidated. The expression of BNIP3, EC-SOD, and GSTP1 were studied by using Maxima@SYBR-green based real-time qPCR approach in peripheral blood samples. Combined bisulfite restriction analysis and methylation-specific PCR were used to study promoter CpG island methylation. Further, the effect of homocysteine on BNIP3 gene expression was studied in human aortic endothelial cells in vitro. CAD cases exhibited upregulation of BNIP3, downregulation of EC-SOD and GSTP1. Hypomethylation of BNIP3 and hypermethylation of EC-SOD were observed in CAD cases. The expression of BNIP3 was positively correlated with homocysteine, MDA, protein carbonyls, and methylene tetrahydrofolate reductase C677T, while showing inverse association with cytosolic serine hydroxymethyl transferase C1420T. The expressions of EC-SOD and GSTP1 showed positive association with thymidylate synthase (TYMS) 2R3R, while inverse association with MDA, protein carbonyls, and methionine synthase reductase (MTRR) A66G. In vitro analysis showed homocysteine-dependent upregulation of BNIP3. The results of this study suggest that the aberrations in one-carbon metabolism appear to induce altered gene expression of EC-SOD, GSTP1, and BNIP3, and thus contribute to the increased oxidative stress and increased susceptibility to CAD.Molecular and Cellular Biochemistry 11/2012; · 2.06 Impact Factor