Counteraction of Oxidative Stress by Vitamin E Affects Epigenetic Regulation by Increasing Global Methylation and Gene Expression of MLH1 and DNMT1 Dose Dependently in Caco-2 Cells

Oxid Med Cell Longev. 2018 Mar 22:2018:3734250. doi: 10.1155/2018/3734250. eCollection 2018.

Abstract

Obesity- or diabetes-induced oxidative stress is discussed as a major risk factor for DNA damage. Vitamin E and many polyphenols exhibit antioxidative activities with consequences on epigenetic regulation of inflammation and DNA repair. The present study investigated the counteraction of oxidative stress by vitamin E in the colorectal cancer cell line Caco-2 under normal (1 g/l) and high (4.5 g/l) glucose cell culture condition. Malondialdehyde (MDA) as a surrogate marker of lipid peroxidation and reactive oxygen species (ROS) was analyzed. Gene expression and promoter methylation of the DNA repair gene MutL homolog 1 (MLH1) and the DNA methyltransferase 1 (DNMT1) as well as global methylation by LINE-1 were investigated. Results revealed a dose-dependent counteracting effect of vitamin E on H2O2-induced oxidative stress. Thereby, 10 μM vitamin E proved to be more efficient than did 50 μM in reducing MDA. Further, an induction of MLH1 and DNMT1 gene expression was noticed, accompanied by an increase in global methylation. Whether LINE-1 hypomethylation is a cause or effect of oxidative stress is still unclear. In conclusion, supplementation of exogenous antioxidants like vitamin E in vitro exhibits beneficial effects concerning oxidative stress as well as epigenetic regulation involved in DNA repair.

MeSH terms

  • Caco-2 Cells
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / genetics
  • Colorectal Neoplasms / metabolism
  • DNA (Cytosine-5-)-Methyltransferase 1 / biosynthesis
  • DNA (Cytosine-5-)-Methyltransferase 1 / genetics*
  • DNA (Cytosine-5-)-Methyltransferases / metabolism*
  • DNA Methylation / drug effects*
  • Dose-Response Relationship, Drug
  • Epigenesis, Genetic / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glucose / administration & dosage
  • Glucose / metabolism
  • Humans
  • Long Interspersed Nucleotide Elements
  • MutL Protein Homolog 1 / biosynthesis
  • MutL Protein Homolog 1 / genetics*
  • Oxidative Stress / drug effects*
  • Oxidative Stress / genetics
  • Promoter Regions, Genetic
  • Reactive Oxygen Species / metabolism
  • Vitamin E / pharmacology*

Substances

  • MLH1 protein, human
  • Reactive Oxygen Species
  • Vitamin E
  • DNA (Cytosine-5-)-Methyltransferase 1
  • DNA (Cytosine-5-)-Methyltransferases
  • DNMT1 protein, human
  • MutL Protein Homolog 1
  • Glucose