title: Cleavage of BCR-ABL transcripts at the T315I point mutation by DNAzyme promotes apoptotic cell death in imatinib-resistant BCR-ABL leukemic cells.
abstract: The BCR-ABL fusion transcript encodes the BCR-ABL tyrosine kinase (TK), which causes chronic myelogenous leukemia (CML). Although the TK inhibitor imatinib mesylate, which targets the BCR-ABL protein, has been proven to be effective in controlling leukemic growth, imatinib resistance has been observed with disease relapse because of point mutations in the ABL gene that inhibit imatinib efficacy. In this study, we designed oligodeoxyribozymes (DNAzymes) that specifically target and cleave both the junction sequence and the site of the point mutation (T315I), conferring imatinib resistance in BCR-ABL mRNA. DNAzymes significantly induced apoptosis and inhibited proliferation in wild-type and T315I-mutant BCR-ABL-positive cells. Selective cleavage of T315I-mutant ABL mRNA by DNAzyme (T315I Dz) led to cell cycle arrest in G0/G1 phase, with induction of caspase-3/-7 in imatinib-resistant BCR-ABL-positive cells harboring the T315I mutation. Moreover, cotreatment with the DNAzyme targeting the T315I mutation and imatinib resulted in enhanced inhibition of proliferation and induction of apoptosis in T315I leukemic cells as compared with imatinib alone, thereby antagonizing imatinib resistance in CML cells bearing T315I-mutant BCR-ABL. Therefore, cleavage of T315I-mutant ABL mRNA by DNAzyme combined with imatinib treatment may be an alternative approach to overcoming imatinib resistance in leukemic cells.
authors: Department of Bioscience and Biotechnology, Konkuk University, Seoul Republic of Korea.
authors: J E
authors: JE
authors: Kim
authors: S
authors: S
authors: Yoon
authors: B-R
authors: BR
authors: Choi
authors: K P
authors: KP
authors: Kim
authors: Y-H
authors: YH
authors: Cho
authors: W
authors: W
authors: Jung
authors: D-W
authors: DW
authors: Kim
authors: S
authors: S
authors: Oh
authors: D-E
authors: DE
authors: Kim
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics*; D020029:Base Pairing; D001483:Base Sequence; D001549:Benzamides / Q000494:pharmacology; D002384:Catalysis; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics; D021881:DNA, Catalytic / Q000235:genetics* / Q000378:metabolism; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D016044:Fusion Proteins, bcr-abl / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic; D000068877:Imatinib Mesylate; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D010879:Piperazines / Q000494:pharmacology; D017354:Point Mutation; D011743:Pyrimidines / Q000494:pharmacology; D014158:Transcription, Genetic
chemical_list: D001549:Benzamides; D021881:DNA, Catalytic; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate; D016044:Fusion Proteins, bcr-abl