Activation of stress response gene SIRT1 by BCR-ABL promotes leukemogenesis

Area of Science:

• Oncology
• Molecular Biology
• Hematology

Background:

• Imatinib is a tyrosine kinase inhibitor effective against chronic myelogenous leukemia (CML).
• Primary and acquired resistance to imatinib limits its efficacy in CML treatment.
• The molecular mechanisms underlying CML resistance to tyrosine kinase inhibitors are not fully elucidated.

Purpose of the Study:

• To investigate the role of the mammalian stress response gene SIRT1 in CML.
• To determine if SIRT1 activation contributes to CML cell resistance to imatinib.
• To explore SIRT1 as a potential therapeutic target for CML.

Main Methods:

• Investigated BCR-ABL-mediated activation of SIRT1 expression in hematopoietic progenitor cells.
• Analyzed the involvement of STAT5 signaling in SIRT1 activation.
• Assessed the impact of SIRT1 inhibition on CML cell survival, proliferation, and apoptosis.
• Utilized SIRT1 knockout mice and tenovin-6 (SIRT1 inhibitor) in a CML mouse model.
• Evaluated the combination therapy of SIRT1 knockout/inhibition with imatinib.

Main Results:

• BCR-ABL activates SIRT1 expression via STAT5 signaling in hematopoietic progenitor cells.
• SIRT1 promotes CML cell survival and proliferation through deacetylation of substrates like FOXO1, p53, and Ku70.
• SIRT1 inhibition sensitizes CML cells to imatinib-induced apoptosis.
• SIRT1 knockout or inhibition with tenovin-6 suppresses BCR-ABL-induced transformation and CML-like disease progression in mice.
• Combined SIRT1 inhibition and imatinib treatment significantly improves survival in CML mice.

Conclusions:

• SIRT1 is a novel survival pathway activated by BCR-ABL in hematopoietic progenitor cells.
• SIRT1 plays a critical role in CML oncogenic transformation and leukemogenesis.
• Targeting SIRT1 offers a promising strategy to overcome imatinib resistance in CML treatment.