Identifying Targeted Therapies for CBFA2T3::GLIS2 Acute Myeloid Leukemia.

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Pediatric acute myeloid leukemia (AML) with the CBFA2T3::GLIS2 fusion is a high-risk subgroup with limited therapeutic options.
• Targeted therapies are needed to improve outcomes for patients with this specific AML subtype.

Purpose of the Study:

• To identify novel therapeutic targets for CBFA2T3::GLIS2 fusion-positive pediatric AML.
• To investigate the mechanisms of resistance to JAK2 inhibition and explore combination strategies.

Main Methods:

• Genome-scale CRISPR-Cas9 screening to identify dependencies.
• Doxycycline-inducible JAK2 knockout system for validation.
• CRISPR-Cas9 ruxolitinib anchor screening to identify resistance mechanisms.
• In vitro and in vivo studies using cell lines and patient-derived xenografts (PDX).

Main Results:

• CBFA2T3::GLIS2 AML exhibits a selective dependency on JAK2.
• JAK2 inhibition impairs proliferation and induces apoptosis in vitro and in vivo.
• MAPK pathway activation, driven by NRAS mutations, confers resistance to JAK2 inhibitors.
• Combination therapy with JAK2 and MEK inhibitors demonstrates synergistic effects.

Conclusions:

• JAK2 is a critical dependency in CBFA2T3::GLIS2 AML.
• Targeting the MAPK pathway in combination with JAK2 inhibition is a promising therapeutic strategy for this AML subtype.
• Further investigation of combination therapies is warranted for this poor-prognostic AML group.