NPM1-Mutated Patient-Derived AML Cells Are More Vulnerable to Rac1 Inhibition

Area of Science:

• Hematology
• Oncology
• Molecular Biology

Background:

• Acute myeloid leukemia (AML) has a poor prognosis, particularly in older adults.
• Chemoresistance remains a significant challenge in AML treatment.
• Targeted therapies offer a potential strategy to improve survival rates.

Purpose of the Study:

• To investigate the efficacy of inhibiting the signaling molecule ras-related C3 botulinum toxin substrate 1 (Rac1) in primary AML cells.
• To evaluate the antiproliferative and pro-apoptotic effects of five novel Rac1 inhibitors.
• To identify potential predictive markers for treatment response in AML.

Main Methods:

• Primary leukemia cells from 79 AML patients were treated with five Rac1 inhibitors (ZINC69391, ITX3, EHOP-016, 1A-116, NSC23766).
• In vitro assays assessed cell proliferation, apoptosis, and necrosis.
• Cytokine profiles in culture media were analyzed.

Main Results:

• All five Rac1 inhibitors demonstrated antiproliferative effects with IC50 values ranging from 3–24 µM.
• Significant apoptosis and necrosis were induced by the inhibitors.
• NPM1-mutated and CD34-negative AML samples showed a higher antiproliferative response.
• NPM1 mutations were associated with reduced viability upon treatment with specific inhibitors.
• Key leukemogenic cytokines were reduced, notably by 1A-116 and NSC23766.

Conclusions:

• Rac1 inhibition exhibits potent anti-leukemic effects in primary AML cells.
• NPM1-mutated AML samples appear more sensitive to Rac1 inhibition.
• Rac1 inhibitors represent a promising targeted therapy approach for AML, potentially overcoming chemoresistance.