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Gene Review

CYP26A1  -  cytochrome P450, family 26, subfamily A,...

Homo sapiens

Synonyms: CP26, CYP26, Cytochrome P450 26A1, Cytochrome P450 retinoic acid-inactivating 1, Cytochrome P450RAI, ...
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Disease relevance of CYP26A1


High impact information on CYP26A1


Chemical compound and disease context of CYP26A1


Biological context of CYP26A1


Anatomical context of CYP26A1


Associations of CYP26A1 with chemical compounds

  • Throughout development CYP26A1 degrades RA in a horizontal region that extends across the retina, but during later embryonic and postnatal retina maturation this function is reinforced by another enzyme, CYP26C1 [18].
  • The potent inhibitory activity of novel 2-benzyltetralone and 2-benzylidenetetralone derivatives vs liver microsomal retinoic acid metabolizing enzymes and a MCF-7 CYP26A1 cell assay is described [13].
  • Both ATRA and 13cisRA dramatically induced the expression of CYP26A1 in SH-SY5Y cells, and treatment with R116010, but not acitretin, potentiated the RA-induced expression of a reporter gene and CYP26A1 [19].
  • Other retinoids (retinol, 9-cis-RA, and 13-cis-RA) also induced significant CYP26A1 expression in HepG2 and NB4 cells [2].
  • Specifically, CYP26C1 can also recognize and metabolize 9-cis-RA and is much less sensitive than the other CYP26 family members to the inhibitory effects of ketoconazole [20].

Regulatory relationships of CYP26A1

  • Because CYP26A1 expression could not be induced by RAR ligands alone, NB4 cells were then co-treated with the RXR agonist BMS649 [21].

Other interactions of CYP26A1

  • Transiently transfected cells expressing CYP26C1 convert atRA to polar water-soluble metabolites similar to those generated by CYP26A1 and -B1 [20].
  • We have previously identified two cytochrome P450s, P450RAI-1 and P450RAI-2 (herein named CYP26A1 and CYP26B1), which were shown to be responsible for catabolism of atRA both in the embryo and the adult [20].
  • Elevated levels of CYP26A1 protein and metabolism of 4-HPR to 4-oxo-4-HPR were found in A2780 cells transfected with RARbeta and to a lesser extent in those transfected with RARgamma [8].
  • In A2780/HPR cells continuously treated with 4-HPR and producing 4-oxo-4-HPR, CYP26A1 and CRBP-I were markedly up-regulated compared with A2780 untreated cells [8].
  • cDNA cloning of human retinoic acid-metabolizing enzyme (hP450RAI) identifies a novel family of cytochromes P450 [15].

Analytical, diagnostic and therapeutic context of CYP26A1

  • Our data suggest that upregulation of CYP26A1 expression in intestinal, endothelial, liver, and APL cells and metabolism of ATRA may play a role in rapid clearance of ATRA after continuous oral administration [2].
  • In this report, we describe the identification, molecular cloning, and substrate characterization of a third member of the CYP26 family, named CYP26C1 [20].
  • PCR amplifications with two sets of degenerate primers that were targeted to CYP26-specific regions were performed with cDNAs from human fetal liver and brain as templates [22].
  • A Northern blot containing poly(A+)RNAs from 43 human adult and 7 human fetal tissues was tested for CYP26 expression [22].
  • In a model of chronic vitamin A ingestion during aging, CYP26 mRNA expression, determined by Northern blot and RT-PCR analysis, increased progressively with dietary vitamin A (P<0.0001; marginal < control < supplemented) and age (P<0.003) [23].


  1. Evidence for a functional genetic polymorphism of the human retinoic acid-metabolizing enzyme CYP26A1, an enzyme that may be involved in spina bifida. Rat, E., Billaut-Laden, I., Allorge, D., Lo-Guidice, J.M., Tellier, M., Cauffiez, C., Jonckheere, N., van Seuningen, I., Lhermitte, M., Romano, A., Guéant, J.L., Broly, F. Birth Defects Res. Part A Clin. Mol. Teratol. (2006) [Pubmed]
  2. Regulation of a highly specific retinoic acid-4-hydroxylase (CYP26A1) enzyme and all-trans-retinoic acid metabolism in human intestinal, liver, endothelial, and acute promyelocytic leukemia cells. Ozpolat, B., Mehta, K., Lopez-Berestein, G. Leuk. Lymphoma (2005) [Pubmed]
  3. The effect of cellular retinoic acid binding protein-I expression on the CYP26-mediated catabolism of all-trans retinoic acid and cell proliferation in head and neck squamous cell carcinoma. Won, J.Y., Nam, E.C., Yoo, S.J., Kwon, H.J., Um, S.J., Han, H.S., Kim, S.H., Byun, Y., Kim, S.Y. Metab. Clin. Exp. (2004) [Pubmed]
  4. Up-regulation of CYP26A1 in adenomatous polyposis coli-deficient vertebrates via a WNT-dependent mechanism: implications for intestinal cell differentiation and colon tumor development. Shelton, D.N., Sandoval, I.T., Eisinger, A., Chidester, S., Ratnayake, A., Ireland, C.M., Jones, D.A. Cancer Res. (2006) [Pubmed]
  5. The retinoid anticancer signal: mechanisms of target gene regulation. Liu, T., Bohlken, A., Kuljaca, S., Lee, M., Nguyen, T., Smith, S., Cheung, B., Norris, M.D., Haber, M., Holloway, A.J., Bowtell, D.D., Marshall, G.M. Br. J. Cancer (2005) [Pubmed]
  6. Genetic evidence that oxidative derivatives of retinoic acid are not involved in retinoid signaling during mouse development. Niederreither, K., Abu-Abed, S., Schuhbaur, B., Petkovich, M., Chambon, P., Dollé, P. Nat. Genet. (2002) [Pubmed]
  7. Cyp26 enzymes generate the retinoic acid response pattern necessary for hindbrain development. Hernandez, R.E., Putzke, A.P., Myers, J.P., Margaretha, L., Moens, C.B. Development (2007) [Pubmed]
  8. Identification of the fenretinide metabolite 4-oxo-fenretinide present in human plasma and formed in human ovarian carcinoma cells through induction of cytochrome P450 26A1. Villani, M.G., Appierto, V., Cavadini, E., Valsecchi, M., Sonnino, S., Curley, R.W., Formelli, F. Clin. Cancer Res. (2004) [Pubmed]
  9. Retinol conversion to retinoic acid is impaired in breast cancer cell lines relative to normal cells. Mira-Y-Lopez, R., Zheng, W.L., Kuppumbatti, Y.S., Rexer, B., Jing, Y., Ong, D.E. J. Cell. Physiol. (2000) [Pubmed]
  10. R115866 inhibits all-trans-retinoic acid metabolism and exerts retinoidal effects in rodents. Stoppie, P., Borgers, M., Borghgraef, P., Dillen, L., Goossens, J., Sanz, G., Szel, H., Van Hove, C., Van Nyen, G., Nobels, G., Vanden Bossche, H., Venet, M., Willemsens, G., Van Wauwe, J. J. Pharmacol. Exp. Ther. (2000) [Pubmed]
  11. A second CYP26 P450 in humans and zebrafish: CYP26B1. Nelson, D.R. Arch. Biochem. Biophys. (1999) [Pubmed]
  12. Homology model of human retinoic acid metabolising enzyme cytochrome P450 26A1 (CYP26A1): active site architecture and ligand binding. Gomaa, M.S., Yee, S.W., Milbourne, C.E., Barbera, M.C., Simons, C., Brancale, A. Journal of enzyme inhibition and medicinal chemistry. (2006) [Pubmed]
  13. Novel tetralone-derived retinoic acid metabolism blocking agents: synthesis and in vitro evaluation with liver microsomal and MCF-7 CYP26A1 cell assays. Yee, S.W., Jarno, L., Gomaa, M.S., Elford, C., Ooi, L.L., Coogan, M.P., McClelland, R., Nicholson, R.I., Evans, B.A., Brancale, A., Simons, C. J. Med. Chem. (2005) [Pubmed]
  14. P450RAI (CYP26A1) maps to human chromosome 10q23-q24 and mouse chromosome 19C2-3. White, J.A., Beckett, B., Scherer, S.W., Herbrick, J.A., Petkovich, M. Genomics (1998) [Pubmed]
  15. cDNA cloning of human retinoic acid-metabolizing enzyme (hP450RAI) identifies a novel family of cytochromes P450. White, J.A., Beckett-Jones, B., Guo, Y.D., Dilworth, F.J., Bonasoro, J., Jones, G., Petkovich, M. J. Biol. Chem. (1997) [Pubmed]
  16. CYP26, a novel mammalian cytochrome P450, is induced by retinoic acid and defines a new family. Ray, W.J., Bain, G., Yao, M., Gottlieb, D.I. J. Biol. Chem. (1997) [Pubmed]
  17. Retinoic acid receptors regulate expression of retinoic acid 4-hydroxylase that specifically inactivates all-trans retinoic acid in human keratinocyte HaCaT cells. Marikar, Y., Wang, Z., Duell, E.A., Petkovich, M., Voorhees, J.J., Fisher, G.J. J. Invest. Dermatol. (1998) [Pubmed]
  18. Retinoids, eye development, and maturation of visual function. Luo, T., Sakai, Y., Wagner, E., Dräger, U.C. J. Neurobiol. (2006) [Pubmed]
  19. Increasing the intracellular availability of all-trans retinoic acid in neuroblastoma cells. Armstrong, J.L., Ruiz, M., Boddy, A.V., Redfern, C.P., Pearson, A.D., Veal, G.J. Br. J. Cancer (2005) [Pubmed]
  20. A novel human cytochrome P450, CYP26C1, involved in metabolism of 9-cis and all-trans isomers of retinoic acid. Taimi, M., Helvig, C., Wisniewski, J., Ramshaw, H., White, J., Amad, M., Korczak, B., Petkovich, M. J. Biol. Chem. (2004) [Pubmed]
  21. Regulation of CYP26A1 expression by selective RAR and RXR agonists in human NB4 promyelocytic leukemia cells. Idres, N., Marill, J., Chabot, G.G. Biochem. Pharmacol. (2005) [Pubmed]
  22. Expression of cytochrome P450RAI (CYP26) in human fetal hepatic and cephalic tissues. Trofimova-Griffin, M.E., Juchau, M.R. Biochem. Biophys. Res. Commun. (1998) [Pubmed]
  23. Regulation of CYP26 (cytochrome P450RAI) mRNA expression and retinoic acid metabolism by retinoids and dietary vitamin A in liver of mice and rats. Yamamoto, Y., Zolfaghari, R., Ross, A.C. FASEB J. (2000) [Pubmed]
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