Abstract
Although targeting the BCR-ABL tyrosine kinase activity by imatinib mesylate has rapidly become first-line therapy in chronic myeloid leukemia (CML), drug resistance suggests that combination therapy directed to a complementing target may significantly improve treatment results. To identify such potential targets, we used lentivirus-mediated RNA interference (RNAi) as a tool for functional genomics in cell lines as well as primary normal and CML CD34+ cells. In a conditional cell culture model, we demonstrate that RNAi-mediated reduction of SHP2, STAT5, and Gab2 protein expression inhibits BCR-ABL-dependent but not cytokine-dependent proliferation in a dose-dependent manner. Similarly, colony formation of purified primary CML but not of normal CD34+ colony-forming cells is specifically reduced by inhibition of SHP2, STAT5, and Gab2 expression, respectively. In addition, coexpression of both anti-BCR-ABL and anti-SHP2 shRNAs from a single lentiviral vector induces stronger inhibition of colony formation as compared to either shRNA alone. The data indicate that BCR-ABL expression may affect the function of normal signaling molecules. Targeting these molecules may harbor significant therapeutic potential for the treatment of patients with CML.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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Antigens, CD34 / metabolism
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Benzamides
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Combined Modality Therapy / methods
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Dose-Response Relationship, Drug
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Drug Resistance, Neoplasm / drug effects
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Drug Resistance, Neoplasm / genetics
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Fusion Proteins, bcr-abl / antagonists & inhibitors
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Fusion Proteins, bcr-abl / metabolism
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Gene Expression Regulation, Leukemic / drug effects
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Gene Expression Regulation, Leukemic / genetics*
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Genetic Therapy / methods
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Genetic Vectors / genetics
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Genetic Vectors / therapeutic use
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Humans
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Imatinib Mesylate
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Intracellular Signaling Peptides and Proteins / genetics*
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Intracellular Signaling Peptides and Proteins / metabolism
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K562 Cells
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Lentivirus
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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 / therapy
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Neoplastic Stem Cells / drug effects
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Neoplastic Stem Cells / metabolism
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Phosphoproteins / genetics*
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Phosphoproteins / metabolism
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Piperazines / therapeutic use
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Protein Kinase Inhibitors / therapeutic use
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatases / genetics*
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Protein Tyrosine Phosphatases / metabolism
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Pyrimidines / therapeutic use
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RNA Interference*
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RNA, Small Interfering / genetics
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RNA, Small Interfering / pharmacology
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STAT5 Transcription Factor / genetics*
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STAT5 Transcription Factor / metabolism
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Signal Transduction / genetics
Substances
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Adaptor Proteins, Signal Transducing
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Antigens, CD34
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Benzamides
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GAB2 protein, human
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Intracellular Signaling Peptides and Proteins
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Phosphoproteins
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Piperazines
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Protein Kinase Inhibitors
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Pyrimidines
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RNA, Small Interfering
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STAT5 Transcription Factor
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Imatinib Mesylate
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Fusion Proteins, bcr-abl
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PTPN11 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 11
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Protein Tyrosine Phosphatases