title: Tyrosine kinase inhibitor resistance in chronic myeloid leukemia cell lines: investigating resistance pathways.
abstract: There are three currently identified secondary resistance mechanisms observed in patients with chronic myeloid leukemia (CML) receiving tyrosine kinase inhibitors (TKIs). These are BCR-ABL kinase domain (KD) mutations, increased BCR-ABL expression, and overexpression of drug-efflux proteins (ABCB1 and ABCG2). To investigate the interplay between these three modes of resistance, three CML blast crisis cell lines (K562, its ABCB1-overexpressing variant K562 Dox, and KU812) were cultured in gradually increasing concentrations of imatinib to 2 μM, or dasatinib to 200 nM. Eight imatinib- and two dasatinib-resistant cell lines were established. Two imatinib-resistant K562 lines both had increased BCR-ABL expression as the apparent mode of resistance. However, when a dasatinib-resistant K562 culture was generated we observed gradually increasing BCR-ABL expression which peaked prior to identification of the T315I mutation. BCR-ABL overexpression followed by mutation development was observed in a further 4/10 cell lines, each with different KD mutations. In contrast, three imatinib-resistant K562 Dox lines exhibited only a further increase in ABCB1 expression. All TKI-resistant cell lines generated had increased IC(50) (dose of drug required to reduce phosphorylation of the adaptor protein p-Crkl by 50%) to imatinib, dasatinib, and nilotinib, regardless of which TKI was used to induce resistance. This suggests that currently available TKIs share the same susceptibilities to drug resistance.
authors: Department of Haematology, SA Pathology, Adelaide, Australia.
authors: Carine
authors: C
authors: Tang
authors: Lisa
authors: L
authors: Schafranek
authors: Dale B
authors: DB
authors: Watkins
authors: Wendy T
authors: WT
authors: Parker
authors: Sarah
authors: S
authors: Moore
authors: Jodi A
authors: JA
authors: Prime
authors: Deborah L
authors: DL
authors: White
authors: Timothy P
authors: TP
authors: Hughes
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001549:Benzamides; D015153:Blotting, Western; D045744:Cell Line, Tumor; D000069439:Dasatinib; D004305:Dose-Response Relationship, Drug; D019008:Drug Resistance, Neoplasm; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D000068877:Imatinib Mesylate; D017404:In Situ Hybridization, Fluorescence; D020128:Inhibitory Concentration 50; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D009154:Mutation; D009363:Neoplasm Proteins / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D011743:Pyrimidines / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013844:Thiazoles / Q000494:pharmacology
chemical_list: C513055:ABCB1 protein, human; C116614:ABCG2 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D048868:Adaptor Proteins, Signal Transducing; D000970:Antineoplastic Agents; D001549:Benzamides; C082869:CRKL protein; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; D013844:Thiazoles; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl; C498826:nilotinib; D000069439:Dasatinib