The Role of Cytochrome P450 Enzymes in Carcinogen Activation and Detoxication: an in Vivo-in Vitro Paradox
Overview
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Many chemical carcinogens require metabolic activation via xenobiotic-metabolizing enzymes in order to exert their genotoxic effects. Evidence from numerous in-vitro studies, utilizing reconstituted systems, microsomal fractions and cultured cells, implicates cytochrome P450 enzymes as being the predominant enzymes responsible for the metabolic activation of many procarcinogens. With the development of targeted gene disruption methodologies, knockout mouse models have been generated that allow investigation of the in-vivo roles of P450 enzymes in the metabolic activation of carcinogens. This review covers studies in which five procarcinogens representing different chemical classes, benzo[a]pyrene, 4-aminobiphenyl (4-ABP), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-9H-pyrido[2,3-b]indole and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, have been administered to different P450 knockout mouse models. Paradoxically, while in-vitro studies using subcellular fractions enriched with P450 enzymes and their cofactors have been widely used to determine the pathways of activation of carcinogens, there is evidence from the in-vivo studies of cases where these same enzyme systems appear to have a more predominant role in carcinogen detoxication rather than activation.
Pagoni M, Zogopoulos V, Kontogiannis S, Tsolakou A, Zoumpourlis V, Tsangaris G Cancer Genomics Proteomics. 2025; 22(2):285-305.
PMID: 39993800 PMC: 11880924. DOI: 10.21873/cgp.20502.
Benzo(a)pyrene and Gut Microbiome Crosstalk: Health Risk Implications.
Mauliasari I, Lee H, Koo S, Hitayezu E, Kieu A, Lee S Toxics. 2025; 12(12).
PMID: 39771153 PMC: 11840287. DOI: 10.3390/toxics12120938.
Elderdery A, Idris H, Alruwaili S, Tebien E, Alsrhani A, Alenazy F Int J Mol Sci. 2025; 25(24.
PMID: 39769254 PMC: 11728260. DOI: 10.3390/ijms252413493.
Human Cytochrome P450 Cancer-Related Metabolic Activities and Gene Polymorphisms: A Review.
Mokhosoev I, Astakhov D, Terentiev A, Moldogazieva N Cells. 2024; 13(23).
PMID: 39682707 PMC: 11639897. DOI: 10.3390/cells13231958.
Phenanthrene-Induced Cytochrome P450 Genes and Phenanthrene Tolerance Associated with Gene.
Cabello-Hurtado F, El Amrani A Plants (Basel). 2024; 13(12).
PMID: 38931123 PMC: 11207427. DOI: 10.3390/plants13121692.