Tyrosine kinase inhibitors, nilotinib and radotinib, suppress both catalytic function and mRNA expression of human cytochrome P450 2J2 and 2C8

Cytochrome P450 (P450 or CYP) 2J2, which metabolizes exogenous medicines and endogenous arachidonic acid to 14,15-epoxyeicosatrienoic acid (14,15-EET), is expressed in various organs and cancer cells. Additionally, CYP2C8 catalyzes the synthesis of 14,15-EET, a vasodilator that promotes cancer cell proliferation. However, the effect of tyrosine kinase inhibitors (TKIs) used in leukemia treatment on CYP2J2 and CYP2C8 remains unclear. This study investigated the effects of 16 TKIs used for leukemia treatment on recombinant CYP2J2-and CYP2C8-mediated processes. Among the TKIs, nilotinib and radotinib strongly inhibited CYP2J2-dependent astemizole O-demethylation and rivaroxaban hydroxylation, and CYP2C8-mediated paclitaxel 6α-hydroxylation (<20 %), with competitive inhibition constants of 0.41 and 0.22 μM, respectively (for astemizole O-demethylation). Nilotinib and radotinib suppressed CYP2J2-and CYP2C8-catalyzed arachidonic acid epoxidation and decreased their mRNA expression in Huh-7 cells (possibly via the peroxisome proliferator-activated receptor α pathway). Given that their inhibition constants are lower than their reported plasma concentrations, both may substantially suppress CYP2J2 and CYP2C8 functional enzyme levels and enzymatic activities in clinical settings. This suppression could potentially alter vasodilation by affecting 14,15-EET production, influencing CYP2J2 and CYP2C8-mediated drug-disease (conditions) and drug-drug interactions.