Pathway-Dependent Inhibition of Paclitaxel Hydroxylation by Kinase Inhibitors and Assessment of Drug–Drug Interaction Potentials

Abstract

Paclitaxel is often used in combination with small molecule kinase inhibitors to enhance antitumor efficacy against various malignancies. Because paclitaxel is metabolized by CYP2C8 and CYP3A4, the possibility of drug-drug interactions mediated by enzyme inhibition may exist between the combining agents. In the present study, a total of 12 kinase inhibitors were evaluated for inhibitory potency in human liver microsomes by monitoring the formation of CYP2C8 and CYP3A4 metabolites simultaneously. For reversible inhibition, nilotinib was found to be the most potent inhibitor against both CYP2C8 and CYP3A4, and the inhibition potency could be explained by strong hydrogen binding based on molecular docking simulations and type II binding based on spectral analysis. Comparison of K i values revealed that the CYP2C8 pathway was more sensitive toward some kinase inhibitors (such as axitinib), while the CYP3A4 pathway was preferentially inhibited by others (such as bosutinib). Pathwaydependent inactivation (time-dependent inhibition) was also observed for a number of kinase inhibitors against CYP3A4 but not CYP2C8. Further studies showed that axitinib had a K I of 0.93 mM and k inact of 0.0137 min 21 , and the observed inactivation toward CYP3A4 was probably due to the formation of reactive intermediate (s). Using a static model, a reasonably accurate prediction of drug-drug interactions was achieved by incorporating parallel pathways and hepatic extraction ratio. The present results suggest that potent and pathway-dependent inhibition of CYP2C8 and/or CYP3A4 pathways by kinase inhibitors may alter the ratio of paclitaxel metabolites in vivo, and that such changes can be clinically relevant as differential metabolism has been linked to paclitaxel-induced neurotoxicity in cancer patients.

In Vitro Assessment of Time-Dependent Inhibitory Effects on CYP2C8 and CYP3A Activity by Fourteen Protein Kinase Inhibitors

“…Apparent K I and k inact values for CYP2C8 inactivation by bosutinib were estimated to 54.8 mM and 0.018 1/min. Our findings differ from those of a recent study, in which bosutinib did not exhibit time-dependent inhibitory effects on paclitaxel 6a-hydroxylation, another CYP2C8 marker reaction (Wang et al, 2014). In addition, in this recent study, the inhibition of paclitaxel p-39-hydroxylation, which was used as a probe for CYP3A4 activity, increased following preincubation with NADPH as compared with no preincubation.…”

“…The bosutinib results of the recent study correspond well with the inhibitory characteristics of bosutinib isomer 1 in our study. It should also be noted that this recent study observed weak mechanism-based inhibition of CYP3A4 by axitinib (Wang et al, 2014). In our study, detailed timedependent inhibition studies were not carried out with axitinib, because preincubation reduced its IC 50 CYP3A inhibition by less than 1.5-fold, which is a common criterion for time-dependent inhibition studies (Grimm et al, 2009).…”

CYP2C8-mediated interaction between repaglinide and steviol acyl glucuronide: In vitro investigations using rat and human matrices and in vivo pharmacokinetic evaluation in rats

“…The monitored ion transitions and collision energy (CE) were as follows: m/z 493.2 (M-H) / 317.3 and À25 V for steviol acyl glucuronide, m/z 0.453.3 (MþH) / 230.3 and 33 V for repaglinide, and m/z 469.5 (MþH) / 246.3 and 33 V for 3 0 -hydroxy repaglinide, respectively. The LC-MS/MS quantitation method of 6a-hydroxypaclitaxel was previously described (Wang et al, 2014b). Data were collected and processed using the AB Sciex Analyst 1.5.2 data collection and integration software.…”

Role of Cytochrome P450 Enzymes in the Metabolic Activation of Tyrosine Kinase Inhibitors

“…This topic has been reviewed, with excellent articles by Duckett and Cameron, [11] Stepan et al [13] and Teo et al [14] Reactive metabolites have been identified for the following clinically available tyrosine kinase inhibitors: dasitinib [15], gefitinib [16]. erlotinib [17], lapatinib [18,19], imatinib [20], axitinib [21], ponatinib [22], sunitinib [23], as well as investigational tyrosine kinase inhibitors. The purpose of the present review is to (1) provide updates on recently characterized bioactivation mechanisms of selected tyrosine kinase inhibitors, (2) discuss progress towards elucidating the cellular mechanisms of hepatocellular injury related to tyrosine kinase inhibitors, and (3) briefly discuss recent findings related to risk factors of tyrosine kinase inhibitor-induced hepatotoxicity.…”