Vitamin A and β-carotene influence the level of benzo[a]pyrene-induced DNA adducts and DNA-repair activities in hamster tracheal epithelium in organ culture
article
Although most studies concerning the effect of vitamin A and β-carotene on chemical carcinogenesis are focused on tumour promotion and progression, these compounds may affect initiation as well. In this study the influence of vitamin A and β-carotene on unscheduled DNA synthesis (UDS) was investigated in hamster tracheal epithelium in organ culture exposed to benzo[a]pyrene (B[a]P). DNA-repair activities were compared with the level of B[a]P-DNA adducts as measured both by 32P-postlabeling and by immunocytochemical detection. In hamster tracheal epithelial cells, both vitamin A and β-carotene significantly increased B[a]P-induced UDS, with 40% and 45%, respectively. At the same time, vitamin A and β-carotene decreased the level of B[a]P-DNA adducts in these cells with 18% and 400%, respectively as measured by 32P-postlabeling and with 12% and 35%, respectively as measured by immunocytochemistry. The effect of vitamin A on B[a]P-induced UDS and DNA-adduct levels in hamster tracheal epithelium appeared to depend on the dose of B[a]P vis-a-vis the concentration of vitamin A. The results of the present study show that both vitamin A and β-carotene cause a decrease in B[a]P-DNA adduct levels by enhancing DNA-repair activities. Because the formation of B[a]P-DNA adducts is considered to be an early step in respiratory tract carcinogenesis, it is suggested that enhancement of DNA-repair activities by vitamin A and the subsequent removal of DNA adducts may be one of the mechanisms involved in vitamin A-mediated protection against cancer.
Topics
β-caroteneBenzo[a]pyreneDNA adductsDNA repairTracheal organ cultureVitamin ABenzo[a]pyreneBeta caroteneRetinolAnimal tissueChemical carcinogenesisControlled studyDNA adductDNA repairHamsterImmunocytochemistryNonhumanOrgan culturePriority journalRespiratory systemTrachea mucosaUnscheduled dna synthesisAnimalBenzo(a)pyrenebeta CaroteneCarotenoidsDNA AdductsDNA DamageDNA RepairEpitheliumHamstersIn VitroMesocricetusOrgan CultureSupport, Non-U.S. Gov'tTracheaVitamin AAnimaliaCricetinae
TNO Identifier
232996
ISSN
03043835
Source
Cancer Letters, 91(2), pp. 205-214.
Pages
205-214
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