title: Inhibition of DNA synthesis in Caco-2 cells by oxidative stress: amelioration by epidermal growth factor.
abstract: The role of oxidative stress in the regulation of intestinal epithelial proliferation was examined by evaluating the effect of H2O2 and xanthine oxidase + xanthine (XO + X) on [3H]thymidine incorporation into DNA in Caco-2 cells. DNA synthesis was highest 4 and 5 days after seeding, while it declined rapidly between 5 and 12 days. Pretreatment for 0.5-24 h with H2O2 or XO + X reduced DNA synthesis on 4- to 6-day-old, but not on 7- to 20-day-old cells. The effect of XO + X on DNA synthesis was significantly reduced by catalase, superoxide dismutase, and ferric chloride, but pretreatment with deferoxamine potentiated XO + X-induced inhibition of DNA synthesis. Coadministration of epidermal growth factor (EGF) for 24 hr reduced the H2O2 and XO + X-induced inhibition of DNA synthesis; this effect of EGF was not observed up to 8 hr. Results show that O2- and H2O2 rapidly inhibit DNA synthesis in Caco-2 cells and that EGF restores DNA synthesis in oxidant-treated cells.
authors.affiliation: Department of Pediatrics, Medical University of South Carolina, Charleston 29425, USA.
authors.forename: J A
authors.initials: JA
authors.lastname: Engler
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.forename: L
authors.initials: L
authors.lastname: Li
authors.forename: R K
authors.initials: RK
authors.lastname: Rao
mesh_terms: D018938:Caco-2 Cells; D002614:Chelating Agents / Q000494:pharmacology; D004247:DNA / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D003676:Deferoxamine / Q000494:pharmacology; D004357:Drug Synergism; D004815:Epidermal Growth Factor / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism*; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D013936:Thymidine / Q000037:antagonists & inhibitors / Q000378:metabolism; D019820:Xanthine / Q000494:pharmacology; D014969:Xanthine Oxidase / Q000494:pharmacology
chemical_list: D002614:Chelating Agents; D016877:Oxidants; D019820:Xanthine; D004815:Epidermal Growth Factor; D004247:DNA; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D003676:Deferoxamine; D013936:Thymidine