Identification of Wee1 as a novel therapeutic target for mutant RAS-driven acute leukemia and other malignancies

Area of Science:

• Oncology
• Molecular Biology
• Drug Discovery

Background:

• Directly targeting mutated rat sarcoma (RAS) oncogenes remains a significant challenge in cancer therapy.
• Previous attempts to inhibit individual RAS pathway mediators have yielded limited clinical success.

Purpose of the Study:

• To identify novel therapeutic strategies for RAS-mutated cancers.
• To investigate the synergistic effects of combining mammalian target of rapamycin (mTOR) inhibition with other agents in mutant RAS-positive leukemia.

Main Methods:

• A chemical screen was employed to identify compounds potentiating mTOR inhibition in mutant RAS-positive leukemia.
• The efficacy of the identified Wee1 inhibitor, MK-1775, in combination with mTOR inhibition was assessed in various cancer cell lines and patient samples.
• Target engagement and downstream signaling effects, including apoptosis induction, were evaluated.

Main Results:

• A Wee1 inhibitor was identified as a synergistic partner with mTOR inhibitors in mutant RAS-positive acute myelogenous leukemia (AML), neuroblastoma RAS viral oncogene homolog (NRAS), and kirsten RAS viral oncogene homolog (KRAS) models.
• The combination therapy enhanced dephosphorylation of AKT, 4E-binding protein 1, and s6 kinase, leading to increased apoptosis.
• The findings were validated in other RAS-mutated malignancies, including melanoma, colorectal, pancreatic, and lung cancers, with demonstrated tumor growth inhibition in preclinical models.

Conclusions:

• The combination of Wee1 and mTOR inhibition represents a novel and effective therapeutic strategy for mutant RAS-positive leukemias.
• This approach shows potential for treating a broader range of RAS-expressing malignancies.