1276090-87-9Relevant articles and documents
Characterization of the metabolism of fenretinide by human liver microsomes, cytochrome P450 enzymes and UDP-glucuronosyltransferases
Illingworth,Boddy,Daly,Veal
, p. 989 - 999 (2011)
Background and Purpose Fenretinide (4-HPR) is a retinoic acid analogue, currently used in clinical trials in oncology. Metabolism of 4-HPR is of particular interest due to production of the active metabolite 4-oxo 4-HPR and the clinical challenge of obtaining consistent 4-HPR plasma concentrations in patients. Here, we assessed the enzymes involved in various 4-HPR metabolic pathways. Experimental Approach Enzymes involved in 4-HPR metabolism were characterized using human liver microsomes (HLM), supersomes over-expressing individual human cytochrome P450s (CYPs), uridine 5-diphospho-glucoronosyl transferases (UGTs) and CYP2C8 variants expressed in Escherichia coli. Samples were analysed by high-performance liquid chromatography and liquid chromatography/mass spectrometry assays and kinetic parameters for metabolite formation determined. Incubations were also carried out with inhibitors of CYPs and methylation enzymes. Key Results HLM were found to predominantly produce 4-oxo 4-HPR, with an additional polar metabolite, 4-hydroxy 4-HPR (4-OH 4-HPR), produced by individual CYPs. CYPs 2C8, 3A4 and 3A5 were found to metabolize 4-HPR, with metabolite formation prevented by inhibitors of CYP3A4 and CYP2C8. Differences in metabolism to 4-OH 4-HPR were observed with 2C8 variants, CYP2C8 4 exhibited a significantly lower Vmax value compared with 1. Conversely, a significantly higher Vmax value for CYP2C8 4 versus 1 was observed in terms of 4-oxo formation. In terms of 4-HPR glucuronidation, UGTs 1A1, 1A3 and 1A6 produced the 4-HPR glucuronide metabolite. Conclusions and Implications The enzymes involved in 4-HPR metabolism have been characterized. The CYP2C8 isoform was found to have a significant effect on oxidative metabolism and may be of clinical relevance.
