Lee, Tai-Sung; Ma, Wanlong; Zhang, Xi; Giles, Francis; Cortes, Jorge; Kantarjian, Hagop; Albitar, Maher
BCR-ABL alternative splicing as a common mechanism for imatinib resistance: evidence from molecular dynamics simulations
MOLECULAR CANCER THERAPEUTICS, 7:3834-3841, DEC 2008

Rare cases of chronic myelogenous leukemia (CML) express high levels of alternatively spliced BCR-ABL mRNA with a 35-bp insertion (35INS) between ABL kinase domain exons 8 and 9. This insertion results in a frameshift leading to the addition of 10 residues and truncation of 653 residues due to early termination. Sensitive PCR-based testing showed that 32 of 52 (62%) imatinib-resistant CML patients in chronic phase and 8 of 38 (21%) in accelerated or blast crisis expressed varying levels of the alternatively spliced BCR-ABL mRNA. A three-dimensional structural model of the 35INS ABL kinase domain complexed with imatinib was built using homology modeling, followed by molecular dynamics simulations. Simulation results showed that the new residues cause a significant global conformational change, altering imatinib binding in a way similar to that of the T315I mutation and, therefore, providing resistance to imatinib that depends on the level of expression. [Mol Cancer Ther 2008;7(12):3834-41]

DOI:10.1158/1535-7163.MCT-08-0482

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