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Published on: June 17, 2022
Targeting cell cycle and apoptosis to overcome chemotherapy resistance in acute myeloid leukemia
Victoria Y Ling1,2,3, Jasmin Straube1,2, William Godfrey1
1QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia.
Abstract:
Chemotherapy-resistant acute myeloid leukemia (AML), frequently driven by clonal evolution, has a dismal prognosis. A genome-wide CRISPR knockout screen investigating resistance to doxorubicin and cytarabine (Dox/AraC) in human AML cell lines identified gene knockouts involving AraC metabolism and genes that regulate cell cycle arrest (cyclin dependent kinase inhibitor 2A (CDKN2A), checkpoint kinase 2 (CHEK2) and TP53) as contributing to resistance. In human AML cohorts, reduced expression of CDKN2A conferred inferior overall survival and CDKN2A downregulation occurred at relapse in paired diagnosis-relapse samples, validating its clinical relevance. Therapeutically targeting the G1S cell cycle restriction point (with CDK4/6 inhibitor, palbociclib and KAT6A inhibitor, WM-1119, to upregulate CDKN2A) synergized with chemotherapy. Additionally, direct promotion of apoptosis with venetoclax, showed substantial synergy with chemotherapy, overcoming resistance mediated by impaired cell cycle arrest. Altogether, we identify defective cell cycle arrest as a clinically relevant contributor to chemoresistance and identify rationally designed therapeutic combinations that enhance response in AML, potentially circumventing chemoresistance.
Insights
Defective cell cycle arrest contributes to chemotherapy resistance in acute myeloid leukemia (AML). Targeting cell cycle or apoptosis synergizes with chemotherapy, improving AML treatment outcomes.
Area of Science:
- Hematology
- Oncology
- Molecular Biology
Background:
- Chemotherapy resistance in acute myeloid leukemia (AML) leads to poor patient outcomes.
- Clonal evolution is a key driver of resistance in AML.
- Understanding resistance mechanisms is crucial for developing effective AML therapies.
Purpose of the Study:
- To investigate genetic factors contributing to doxorubicin and cytarabine (Dox/AraC) resistance in AML.
- To identify clinically relevant targets for overcoming chemoresistance in AML.
- To evaluate novel therapeutic combinations for AML treatment.
Main Methods:
- Genome-wide CRISPR knockout screens were performed in human AML cell lines.
- Gene expression and survival data from human AML cohorts were analyzed.
- Synergistic effects of combination therapies were assessed in vitro.
Main Results:
- Knockouts in AraC metabolism and cell cycle arrest genes (CDKN2A, CHEK2, TP53) conferred Dox/AraC resistance.
- Reduced CDKN2A expression correlated with inferior survival and was observed at AML relapse.
- Targeting cell cycle (palbociclib, WM-1119) or apoptosis (venetoclax) synergized with chemotherapy.
Conclusions:
- Defective cell cycle arrest is a clinically relevant mechanism of chemoresistance in AML.
- Targeting cell cycle progression or apoptosis can overcome chemoresistance.
- Novel therapeutic combinations show promise for enhancing AML response and circumventing resistance.
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