Stable expression of rat sulfotransferase 1B1 in V79 cells: activation of benzylic alcohols to mutagens.
We have constructed Chinese hamster V79-derived cell lines (V79-rSULT1B1-A and -B) that express rat sulfotransferase 1B1 (rSULT1B1). Sulfotransferase activity towards 1-naphthol was 1020 +/- 220 pmol/min/mg cytosolic protein in V79-rSULT1B1-A cells and 57 +/- 9 pmol/ min/mg in V79-rSULT1B1-B cells. These activities were similar over 100 population doublings and at varying cell densities. Immunostaining indicated a cytoplasmatic localization of rSULT1B1. Expression usually was homogeneous within colonies but showed some variation between colonies. The level of rSULT1B1 protein in V79-rSULT1B1-B cells was similar to that in rat liver but higher than in colon mucosa. The cytotoxicity of the benzylic alcohols 4H-cyclopenta[def]chrysen-4-ol and 6-hydroxymethylbenzo-[a]pyrene was enhanced >100-fold in V79-rSULT1B1-A cells compared with SULT-deficient cells (V79p). Likewise, these compounds showed mutagenic effects (at the hprt locus) in V79-rSULT1B1-A cells starting at a concentration of 0.02 and 0.01 micro M, respectively, but were inactive in V79p cells even at a concentration of 1 micro M. The cell line with the lower expression level, V79-rSULT1B1-B, showed only marginal toxification of the compounds investigated, indicating an important role of the expression level in the test system. A thoroughly characterized mammalian cell system, including positive controls, is now available for studying rSULT1B1-mediated bioactivation of promutagens and protoxicants.
Teubner
Wera
W
Department of Toxicology, German Institute of Human Nutrition (DIfE), 14558 Bergholz-Rehbrücke, Germany.
Meinl
Walter
W
Glatt
Hansruedi
H
D000818:Animals; D001580:Benzopyrenes / Q000378:metabolism* / Q000633:toxicity; D001711:Biotransformation; D002460:Cell Line / Q000187:drug effects / Q000378:metabolism; D002911:Chrysenes / Q000378:metabolism* / Q000633:toxicity; D003106:Colon / Q000201:enzymology; D006224:Cricetinae; D003412:Cricetulus; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004351:Drug Resistance; D004790:Enzyme Induction; D005260:Female; D007413:Intestinal Mucosa / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D009153:Mutagens / Q000378:metabolism* / Q000633:toxicity; D011355:Prodrugs / Q000378:metabolism* / Q000633:toxicity; D051381:Rats; D017208:Rats, Wistar; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013045:Species Specificity; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism*; D013866:Thioguanine / Q000494:pharmacology
D001580:Benzopyrenes; D002911:Chrysenes; D018076:DNA, Complementary; D009153:Mutagens; D011355:Prodrugs; D011993:Recombinant Fusion Proteins; C080738:4H-cyclopenta(def)chrysen-4-ol; C017409:6-(hydroxymethyl)benzo(a)pyrene; C097311:Dopa-tyrosine sulfotransferase; D015238:Sulfotransferases; D013866:Thioguanine