Author:

Keywords:

ATP-Binding Cassette Transporters, Administration, Oral, Animals, Antineoplastic Agents, Biological Transport, COS Cells, Cercopithecus aethiops, Drug Resistance, Multiple, Drug Resistance, Neoplasm, Gene Expression, Humans, Membrane Transport Proteins, Multidrug Resistance-Associated Proteins, Neoplasm Proteins, Neoplasms, Piperazines, Protein-Tyrosine Kinases, Pyrimidines, RNA, Messenger, Receptors, Cytoplasmic and Nuclear, Receptors, Steroid, Reverse Transcriptase Polymerase Chain Reaction, Trans-Activation (Genetics), Transcription Factors, Tumor Cells, Cultured, Science & Technology, Life Sciences & Biomedicine, Oncology, Gleevec, oral bioavailability, drug resistance, ABC transporters, Caco-2 cells, tyrosine kinase inhibitor, pharmacokinetic resistance, gastrointestinal absorption, CANCER RESISTANCE PROTEIN, CHRONIC MYELOID-LEUKEMIA, BREAST-CANCER, TYROSINE KINASE, P-GLYCOPROTEIN, BIOAVAILABILITY, INHIBITOR, STI571, PHARMACOKINETICS, OVEREXPRESSION, ATP Binding Cassette Transporter, Subfamily G, Member 2, Benzamides, Chlorocebus aethiops, Constitutive Androstane Receptor, Imatinib Mesylate, Multidrug Resistance-Associated Protein 2, Pregnane X Receptor, Transcriptional Activation, 1112 Oncology and Carcinogenesis, Oncology & Carcinogenesis, 3101 Biochemistry and cell biology, 3211 Oncology and carcinogenesis

Abstract:

Imatinib mesylate is a selective tyrosine kinase inhibitor that is successfully used in the treatment of Philadelphia-positive chronic and acute leukaemia's, and gastrointestinal stromal tumors. We investigated whether the intended chronic oral administration of imatinib might lead to the induction of the intestinal ABC transport proteins ABCB1, ABCC1 (MRP1), ABCC2 (MRP2) and ABCG2. Using Caco2 cells as an in vitro model for intestinal drug transport, we found that continuous exposure (up to 100 days) with imatinib (10 microM) specifically upregulates the expression of ABCG2 (maximal approximately 17-fold) and ABCB1 (maximal approximately 5-fold). The induction of gene expression appeared to be biphasic in time, with a significant increase in ABCG2 and ABCB1 at day 3 and day 25, respectively, and was not mediated through activation of the human orphan nuclear receptor SXR/NR1I2. Importantly, chronic imatinib exposure of Caco2 cells resulted in a approximately 50% decrease in intracellular accumulation of imatinib, probably by enhanced ABCG2- and ABCB1-mediated efflux, as a result of upregulated expression of these drug pumps. Both ABCG2 and ABCB1 are normally expressed in the gastrointestinal tract and it might be anticipated that drug-induced upregulation of these intestinal pumps could reduce the oral bioavailability of imatinib, representing a novel mechanism of acquired pharmacokinetic drug resistance in cancer patients that are chronically treated with imatinib.