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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP Binding Cassette Transporter, Subfamily B
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ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism
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ATP Binding Cassette Transporter, Subfamily G, Member 2
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ATP-Binding Cassette Transporters / metabolism
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Adaptor Proteins, Signal Transducing / metabolism
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Antineoplastic Agents / pharmacology*
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Benzamides
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Blotting, Western
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Cell Line, Tumor
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Dasatinib
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Dose-Response Relationship, Drug
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Drug Resistance, Neoplasm*
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Flow Cytometry
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Fusion Proteins, bcr-abl / genetics
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Gene Expression Regulation, Neoplastic
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Humans
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Imatinib Mesylate
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In Situ Hybridization, Fluorescence
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Inhibitory Concentration 50
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K562 Cells
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / metabolism
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
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Mutation
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Neoplasm Proteins / metabolism
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Nuclear Proteins / metabolism
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Phosphorylation / drug effects
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Piperazines / pharmacology
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Protein Kinase Inhibitors / pharmacology*
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Pyrimidines / pharmacology
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Reverse Transcriptase Polymerase Chain Reaction
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Thiazoles / pharmacology
Substances
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ABCB1 protein, human
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ABCG2 protein, human
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ATP Binding Cassette Transporter, Subfamily B
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ATP Binding Cassette Transporter, Subfamily B, Member 1
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ATP Binding Cassette Transporter, Subfamily G, Member 2
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ATP-Binding Cassette Transporters
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Adaptor Proteins, Signal Transducing
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Antineoplastic Agents
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Benzamides
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CRKL protein
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Neoplasm Proteins
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Nuclear Proteins
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Piperazines
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Protein Kinase Inhibitors
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Pyrimidines
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Thiazoles
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Imatinib Mesylate
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Fusion Proteins, bcr-abl
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nilotinib
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Dasatinib