Imatinib mesylate induces cisplatin hypersensitivity in Bcr-Abl+ cells by differential modulation of p53 transcriptional and proapoptotic activity
| Autor: | Walter E. Aulitzky, Christiane Markwardt, Matthias Gutekunst, Heiko van der Kuip, Moshe Oren, Ioanna Skorta |
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| Rok vydání: | 2009 |
| Předmět: |
Cancer Research
Transcription Genetic Fusion Proteins bcr-abl bcl-X Protein Apoptosis Cell Cycle Proteins Ataxia Telangiectasia Mutated Proteins Protein Serine-Threonine Kinases Piperazines Mice hemic and lymphatic diseases Leukemia Myelogenous Chronic BCR-ABL Positive Antineoplastic Combined Chemotherapy Protocols medicine Animals Humans Myeloid Cells neoplasms Cisplatin Chemistry Tumor Suppressor Proteins Cell Cycle Imatinib Drug Synergism Cell cycle medicine.disease DNA-Binding Proteins Enzyme Activation Leukemia Imatinib mesylate Pyrimidines Oncology Benzamides Cancer research Imatinib Mesylate Tumor Suppressor Protein p53 K562 Cells Chronic myelogenous leukemia K562 cells medicine.drug DNA Damage |
| Zdroj: | Cancer research. 69(24) |
| ISSN: | 1538-7445 |
| Popis: | Imatinib is highly effective in inducing remission in chronic myelogenous leukemia (CML). However, complete eradication of the malignant clone by imatinib is rare. We investigated the efficacy of combining imatinib with cisplatin. Inhibition of Bcr-Abl by imatinib induced a hypersensitive phenotype both in Bcr-Abl+ cell lines and in CD34+ cells from CML patients. Importantly, cisplatin sensitivity of leukemic cells harboring an inactive Bcr-Abl greatly exceeded that of Bcr-Abl− parental cells. The cisplatin response of Bcr-Abl+ cells treated with imatinib was characterized by an impaired G2-M arrest and by rapid induction of mitochondrial cell death after the first passage through G2. Imatinib abrogated ATM activation on cisplatin selectively in Bcr-Abl+ cells. As a consequence, phosphorylation of p53 on Ser15 and its activity as a transcription factor was significantly diminished. Furthermore, p53 accumulated predominantly in the cytoplasm in Bcr-Abl+ cells treated with imatinib and cisplatin. Silencing of p53 significantly reduced sensitivity to cisplatin in imatinib-treated Bcr-Abl+ cells, indicating that p53 retains its proapoptotic activity. Simultaneous downregulation of Bcl-xL was an additional requirement for cisplatin hypersensitivity, as p53-dependent cell death could be antagonized by exogenous Bcl-xL. We conclude that imatinib sensitizes Bcr-Abl+ cells to cisplatin by simultaneous inhibition of p53 transactivation, induction of p53 accumulation predominantly in the cytoplasm, and reduction of Bcl-xL. [Cancer Res 2009;69(24):9337–45] |
| Databáze: | OpenAIRE |
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