Argonaute 2 modulates EGFR-RAS signaling to promote mutant HRAS and NRAS-driven malignancies

Area of Science:

• Molecular oncology
• Cancer biology
• Signal transduction

Background:

• Activating RAS GTPase mutations fuel approximately 30% of human cancers.
• Argonaute 2 (AGO2) plays a crucial role in KRAS-driven cancers.
• The interaction between AGO2 and RAS in HRAS/NRAS-driven cancers is not well understood.

Purpose of the Study:

• To investigate the novel interaction between AGO2 and RAS in wild-type (WT) and mutant HRAS/NRAS cells.
• To elucidate the mechanism by which AGO2 regulates proliferation in mutant RAS-driven cancers.
• To identify the signaling pathways involved in AGO2-mediated regulation of cancer cell growth.

Main Methods:

• Identification of endogenous AGO2-RAS interaction.
• EGFR-mediated phosphorylation analysis at Y393-AGO2.
• Molecular dynamic simulations to assess protein structure changes.
• AGO2 knockdown experiments in WT and mutant RAS cell lines.
• Oncogene-induced senescence (OIS) assays including β-galactosidase staining.
• Reactive oxygen species (ROS) detection.
• Analysis of PTP1B phosphatase and EGFR-MAPK signaling pathways.

Main Results:

• A novel endogenous interaction between AGO2 and RAS was identified in WT and mutant HRAS/NRAS cells.
• EGFR-mediated phosphorylation of Y393-AGO2 disrupts the RAS binding site, confirmed by molecular dynamics.
• AGO2 knockdown significantly reduced proliferation in mutant HRAS/NRAS cells, inducing OIS.
• OIS was mediated by ROS induction and a novel feed-forward pathway involving PTP1B inhibition and EGFR-MAPK activation.

Conclusions:

• The EGFR-AGO2-RAS signaling axis is critical for the maintenance of mutant HRAS and NRAS-driven malignancies.
• AGO2 is a potential therapeutic target for HRAS/NRAS-driven cancers.
• Disruption of the AGO2-RAS interaction can induce senescence in cancer cells.