title: Effects of vitamins C and E on cytotoxicity induced by N-nitroso compounds, N-nitrosomorpholine and N-methyl-N'-nitro-N-nitrosoguanidine in Caco-2 and V79 cell lines.
abstract: Since N-nitroso compounds as strong carcinogens are closely related to food and nutrition, the cytotoxic effects of N-nitrosomorpholine (NMOR) and N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and their reduction by vitamins C and E were investigated in hamster V79 cells and human colon carcinoma Caco-2 cells. Cytotoxicity was evaluated by the trypan blue exclusion technique in Caco-2 cells and by the plating efficiency assay in V79 cells. NMOR caused a dose-dependent decline of viable cells in both cell lines; MNNG induced a dose-dependent cytotoxic effect only in V79 cells. Pretreatment of cells with vitamin C and vitamin E significantly reduced the cytotoxicity of NMOR, however, both vitamins had not effect on cytotoxicity induced by MNNG. These results suggest that different N-nitroso compounds react differently with cellular macromolecules. Measurement of the level of NMOR-induced DNA strand breaks and alkali-labile sites in both cell types using the alkaline comet assay also indicates a protective effect of both vitamins against the genotoxic effects of NMOR.
authors.affiliation: Department of Mutagenesis and Carcinogenesis, Cancer Research Institute of the Slovak Academy of Sciences, Vlárska 7, 83391, Bratislava, Slovak Republic. exonroso@savba.sk
authors.forename: Sona
authors.initials: S
authors.lastname: Robichová
authors.forename: Darina
authors.initials: D
authors.lastname: Slamenová
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology*; D018938:Caco-2 Cells; D002273:Carcinogens / Q000633:toxicity*; D006224:Cricetinae; D004247:DNA / Q000096:biosynthesis; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008769:Methylnitronitrosoguanidine / Q000633:toxicity*; D009602:Nitrosamines / Q000633:toxicity*; D014810:Vitamin E / Q000494:pharmacology*
chemical_list: D002273:Carcinogens; D009602:Nitrosamines; D008769:Methylnitronitrosoguanidine; D014810:Vitamin E; C002741:N-nitrosomorpholine; D004247:DNA; D001205:Ascorbic Acid