title: Mitochondrial oxidative stress-induced epigenetic modifications in pancreatic epithelial cells.
abstract: Emerging studies have linked prooxidative carbamate compound exposures with various human pathologies including pancreatic cancer. In these studies, our aim was to examine mitochondrial oxidative stress-mediated aberrant chromatin responses in human pancreatic ductal epithelial cells. Posttranslational histone modifications, promoter DNA methylation, and micro-RNA (miRNA) expression patterns were evaluated following induction of mitochondrial oxidative stress by N-succinimidyl N-methylcarbamate exposure. In treated cells, perturbation in mitochondrial machinery led to hypermethylation of p16 and smad4 gene promoters and downregulation of respective gene products. Posttranslational histone modifications that include hypoacetylation of acetylated histone (AcH) 3 and AcH4, hypermethylation of monomethylated histone 3 at lysine 9 and trimethylated histone 4 at lysine 20 ubiquitinated histone (uH) 2A/uH2B, and increased phosphorylation of H2AX and H3 were observed in the treated cells. Altered expression of miRNAs denoted possible location of corresponding genes at oxidatively damaged fragile sites. Collectively, our results provide a direct role of mitochondrial oxidative stress-mediated epigenetic imbalance to perturbed genomic integrity in oxygen radical-induced pancreatic injury. Further, identification and characterization of molecular switches that affect these epigenomic signatures and targets thereof will be imperative to understand the complex role of redox-regulatory network in pancreatic milieu.
authors.affiliation: Translational Research Lab, School of Biological Sciences, Dr Hari Singh Gour Central University, Sagar, Madhya Pradesh, India. Email: pkm_8bh@yahoo.co.uk.
authors.forename: Pradyumna Kumar
authors.initials: PK
authors.lastname: Mishra
authors.forename: Gorantla Venkata
authors.initials: GV
authors.lastname: Raghuram
authors.forename: Deepika
authors.initials: D
authors.lastname: Jain
authors.forename: Subodh Kumar
authors.initials: SK
authors.lastname: Jain
authors.forename: Naveen Kumar
authors.initials: NK
authors.lastname: Khare
authors.forename: Neelam
authors.initials: N
authors.lastname: Pathak
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D016207:Cytokines / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D044127:Epigenesis, Genetic / Q000502:physiology*; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D051901:Smad4 Protein / Q000378:metabolism
chemical_list: D000975:Antioxidants; D016207:Cytokines; D035683:MicroRNAs; D017382:Reactive Oxygen Species; C497796:SMAD4 protein, human; D051901:Smad4 Protein
keywords: DNA methylation; histone modifications; methyl isocyanate; miRNA; pancreatic cancer