Abstract
Clinical studies with the Abl tyrosine kinase inhibitor STI-571 in chronic myeloid leukemia demonstrate that many patients with advanced stage disease respond initially but then relapse. Through biochemical and molecular analysis of clinical material, we find that drug resistance is associated with the reactivation of BCR-ABL signal transduction in all cases examined. In six of nine patients, resistance was associated with a single amino acid substitution in a threonine residue of the Abl kinase domain known to form a critical hydrogen bond with the drug. This substitution of threonine with isoleucine was sufficient to confer STI-571 resistance in a reconstitution experiment. In three patients, resistance was associated with progressive BCR-ABL gene amplification. These studies provide evidence that genetically complex cancers retain dependence on an initial oncogenic event and suggest a strategy for identifying inhibitors of STI-571 resistance.
Publication types
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Comment
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Amino Acid Substitution
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Antineoplastic Agents / metabolism
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Antineoplastic Agents / pharmacology
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Antineoplastic Agents / therapeutic use
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Base Sequence
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Benzamides
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Blast Crisis / genetics
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Cell Line
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Drug Resistance, Neoplasm / genetics
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Fusion Proteins, bcr-abl / metabolism*
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Gene Amplification
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Genes, abl*
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Humans
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Hydrogen Bonding
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Imatinib Mesylate
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / drug therapy*
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Leukemia, Myelogenous, Chronic, BCR-ABL Positive / genetics*
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Molecular Sequence Data
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Philadelphia Chromosome
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Phosphorylation
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Piperazines / metabolism
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Piperazines / pharmacology*
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Piperazines / therapeutic use
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Point Mutation
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Protein Structure, Tertiary
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-abl / antagonists & inhibitors
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Proto-Oncogene Proteins c-abl / chemistry
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Proto-Oncogene Proteins c-abl / genetics*
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Proto-Oncogene Proteins c-abl / metabolism
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Proto-Oncogene Proteins c-crk
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Pyrimidines / metabolism
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Pyrimidines / pharmacology*
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Pyrimidines / therapeutic use
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Recurrence
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Signal Transduction
Substances
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Antineoplastic Agents
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Benzamides
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Piperazines
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-crk
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Pyrimidines
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Imatinib Mesylate
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Fusion Proteins, bcr-abl
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Proto-Oncogene Proteins c-abl