title: PXR-mediated P-glycoprotein induction by small molecule tyrosine kinase inhibitors.
abstract: The rapid development of drug resistance as a result of exposure to small molecule tyrosine kinase inhibitors (TKIs) is an important drawback to the successful use of these agents in the clinic. Although one of the most established mechanisms by which cells acquire drug resistance to anticancer drugs is the up regulation of drug efflux transporters such as P-glycoprotein (PGP), it is currently still unknown whether TKIs have the propensity to induce PGP. The effect of TKIs on the protein expression and activity of PGP was assessed after treatment of LS180 cells with clinically relevant concentrations of the TKIs. In addition, the involvement of the nuclear pregnane X receptor (PXR), a known regulator of PGP expression, was determined. At least five out of the nine tested TKIs (erlotinib, gefitinib, nilotinib, sorafenib, vandetanib) were able to induce the expression of PGP within 48 h in LS180 cells. Accordingly, these TKIs were also shown to affect the accumulation of a P-glycoprotein specific probe substrate. Furthermore, we showed that the pregnane X receptor (PXR), which is an important regulator of PGP induction, is involved in the upregulation of PGP protein expression following exposure to these TKIs. Our data show that PXR-mediated upregulation of PGP expression by TKIs might be a possible mechanism underlying acquired drug resistance in cancer cells.
authors.affiliation: Utrecht University, Faculty of Science, Department of Pharmaceutical Sciences, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Harmsen
authors.forename: I
authors.initials: I
authors.lastname: Meijerman
authors.forename: R F
authors.initials: RF
authors.lastname: Maas-Bakker
authors.forename: J H
authors.initials: JH
authors.lastname: Beijnen
authors.forename: J H M
authors.initials: JH
authors.lastname: Schellens
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D000069347:Erlotinib Hydrochloride; D000077156:Gefitinib; D006801:Humans; D009536:Niacinamide / Q000031:analogs & derivatives / Q000494:pharmacology; D010671:Phenylurea Compounds / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D000077297:Pregnane X Receptor; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011743:Pyrimidines / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology; D011987:Receptors, Steroid / Q000378:metabolism*; D000077157:Sorafenib
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D010671:Phenylurea Compounds; D010880:Piperidines; D000077297:Pregnane X Receptor; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D011799:Quinazolines; D011987:Receptors, Steroid; D009536:Niacinamide; D000077157:Sorafenib; D000069347:Erlotinib Hydrochloride; D011505:Protein-Tyrosine Kinases; C498826:nilotinib; D000077156:Gefitinib; C452423:vandetanib