title: Stabilization of a reactive, electrophilic carcinogen, benzo[a]pyrene diol epoxide, by mammalian cells.
abstract: We have studied several features of the interactions of 7r,8t-dihydroxy-9t,10t-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE-I) with a DNA repair-proficient derivative of Chinese hamster ovary cells (CHO), AT3-2, and with a UV-light sensitive mutant, UVL-10, derived from AT3-2. Methods were developed for quantitating the amount of unhydrolysed BPDE-I associated with cells and for purifying DNA from cells under conditions where artificial labeling during preparation is minimized. In both cell types, about 30% of the BPDE-I added to a cell culture is rapidly taken up by the cells and is maintained in a cellular compartment in which the half-life of BPDE-I is about 10-fold longer than in aqueous medium. The kinetics of covalent binding to DNA were measured in both cell types and found to be described well by a single exponential process with a half-life of about 60 min. This is virtually identical to the half-life for intracellular hydrolysis of BPDE-I (57 min), consistent with the suggestion that this intracellular, relatively stable BPDE-I is responsible for binding.
mesh_terms: D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000378:metabolism / Q000493:pharmacokinetics*; D001692:Biological Transport; D002273:Carcinogens / Q000378:metabolism / Q000493:pharmacokinetics*; D002460:Cell Line; D004247:DNA / Q000378:metabolism*; D004249:DNA Damage; D004101:Dihydroxydihydrobenzopyrenes / Q000493:pharmacokinetics*; D006868:Hydrolysis
chemical_list: D002273:Carcinogens; D004101:Dihydroxydihydrobenzopyrenes; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; D004247:DNA