title: Sulindac and its metabolites induce carcinogen metabolizing enzymes in human colon cancer cells.
abstract: Sulindac is a nonsteroidal antiinflammatory drug that has been demonstrated to be a potent chemopreventive agent against colorectal cancer in both human and animal models. In vivo, sulindac may be reversibly reduced to the active antiinflammatory compound, sulindac sulfide, or irreversibly oxidized to sulindac sulfone. Sulindac has also been shown to inhibit polycyclic aromatic hydrocarbon (PAH)-induced cancer, but the molecular mechanisms of its antitumor effect remain unclear. In this study, we investigated the effects of sulindac and its metabolites on the expression of enzymes that metabolize and detoxify PAHs in 2 human colon cancer cell lines, LS180 and Caco-2. Sulindac and sulindac sulfide induced a sustained, concentration-dependent increase in CYP enzyme activity as well as an increase in the mRNA levels of CYP1A1, CYP1A2 and CYP1B1. Sulindac and sulindac sulfide induced the transcription of the CYP1A1 gene, as measured by the level of heterogeneous nuclear CYP1A1 RNA and verified by the use of actinomycin D as a transcription inhibitor. Chromatin immunoprecipitation assays demonstrated that sulindac and sulindac sulfide also increased the nuclear level of activated aryl hydrocarbon receptor, the transcription factor which mediates CYP expression. Additionally, sulindac and both metabolites increased the activity and mRNA expression of the carcinogen detoxification enzyme NAD(P)H:quinone oxidoreductase, as well as the expression of UDP-glucuronosyltransferase mRNA. These results show an overall upregulation of carcinogen metabolizing enzymes in colon cancer cells treated with sulindac, sulindac sulfide and sulindac sulfone that may contribute to the established chemoprotective effects of these compounds.
authors.affiliation: Division of Nutritional Sciences, Department of Human Ecology, University of Texas at Austin, Austin, TX, USA.
authors.forename: Henry P
authors.initials: HP
authors.lastname: Ciolino
authors.forename: Sara E
authors.initials: SE
authors.lastname: Bass
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: MacDonald
authors.forename: Robert Y S
authors.initials: RY
authors.lastname: Cheng
authors.forename: Grace Chao
authors.initials: GC
authors.lastname: Yeh
mesh_terms: D000970:Antineoplastic Agents / Q000378:metabolism / Q000494:pharmacology*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000378:metabolism*; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013467:Sulindac / Q000378:metabolism / Q000494:pharmacology*; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D013467:Sulindac; D003577:Cytochrome P-450 Enzyme System; D019363:Cytochrome P-450 CYP1A1; D016660:NAD(P)H Dehydrogenase (Quinone); D014453:Glucuronosyltransferase