The novel Chk1 inhibitor MK-8776 sensitizes human leukemia cells to HDAC inhibitors by targeting the intra-S checkpoint and DNA replication and repair
| Autor: | Liang Zhou, Hui Lin, Steven Grant, Maciej Kmieciak, Xin-Yan Pei, Shuang Chen, Yun Dai |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
DNA Replication
Cancer Research DNA Repair DNA repair DNA damage Apoptosis Bone Marrow Cells Biology medicine.disease_cause Hydroxamic Acids Article Histone Deacetylases DNA replication factor CDT1 Antineoplastic Combined Chemotherapy Protocols medicine Humans CHEK1 Vorinostat Cells Cultured Mutation Leukemia Gene Expression Regulation Leukemic medicine.disease Molecular biology CHK1 Inhibitor MK-8776 Histone Deacetylase Inhibitors Pyrimidines Oncology Checkpoint Kinase 1 S Phase Cell Cycle Checkpoints Cancer research biology.protein Pyrazoles Tumor Suppressor Protein p53 Protein Kinases medicine.drug |
| Popis: | Interactions between the novel Chk1 inhibitor MK-8776 and the histone deacetylase (HDAC) inhibitor (HDACI) vorinostat were examined in human leukemia cells harboring wild-type (wt) or deficient p53. MK-8776 synergistically potentiated vorinostat-mediated apoptosis in various p53-wt or -deficient leukemia cell lines, whereas p53 knockdown by short hairpin RNA (shRNA) sensitized p53-wt cells to lethality of this regimen. Leukemia cell lines carrying FLT3-ITD were also sensitive to the MK-8776/vorinostat regimen. Synergistic interactions were associated with inhibition of Chk1 activity, interference with the intra-S-phase checkpoint, disruption of DNA replication, and downregulation of proteins involved in DNA replication (e.g., Cdt1) and repair (e.g., CtIP and BRCA1), resulting in sharp increases in DNA damage, reflected by enhanced γ-H2A.X formation, and apoptosis. Moreover, leukemia cells expressing kinase-dead Chk1 (D130A) or Chk1 shRNA were significantly more sensitive to HDACIs compared with their wt counterparts and displayed downregulation of CtIP and BRCA1 phosphorylation following HDACI exposure. Finally, the MK-8776/vorinostat regimen was active in primary acute myelogenous leukemia (AML) blasts, particularly against the CD34+/CD38−/CD123+ population enriched for leukemia-initiating cells. In contrast, identical regimens were relatively sparing toward normal cord blood CD34+ cells. Together, these findings indicate that the novel Chk1 inhibitor MK-8776 markedly potentiates HDACI lethality in leukemia cells displaying various genetic backgrounds through mechanisms involving disruption of the intra-S checkpoint, DNA replication, and DNA repair. They also argue that leukemic cells, including those bearing oncogenic mutations associated with poor prognosis, for example, p53 deletion/mutation or FLT3-ITD, may also be susceptible to this strategy. Mol Cancer Ther; 12(6); 878–89. ©2013 AACR. |
| Databáze: | OpenAIRE |
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