The relative contributions of CYP3A4 and CYP3A5 to the metabolism of vinorelbine.

ABSTRACT: Vinorelbine is a semisynthetic vinca alkaloid used in the treatment of advanced breast and non-small cell lung cancers. Vincristine, a related vinca alkaloid, is 9-fold more efficiently metabolized by CYP3A5 than by CYP3A4 in vitro. This study quantified the relative contribution of CYP3A4 and CYP3A5 to the metabolism of vinorelbine in vitro using cDNA-expressed human cytochrome P450s (P450s) and human liver microsomes (HLMs). CYP3A4 and CYP3A5 were identified as the P450s capable of oxidizing vinorelbine using a panel of human enzymes and selective P450 inhibitors in HLMs. For CYP3A4 coexpressed with cytochrome b5 (CYP3A4+b5) and CYP3A5+b5, the Michaelis-Menten constants for vinorelbine were 2.6 and 3.6 μM, respectively, but the Vmax of 1.4 pmol/min/pmol was common to both enzymes. In HLM

SUBMITTER: Topletz AR 

PROVIDER: S-EPMC3876810 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature