Identification of a farnesol analog as a Ras function inhibitor using both an in vivo Ras activation sensor and a...

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Ras proteins (K-Ras, N-Ras, H-Ras) are crucial in human cancers, with mutations driving ~85% of cases.
• Ras activity depends on membrane localization, facilitated by farnesylation or geranylgeranylation of the C-terminal CAAX box.

Purpose of the Study:

• To develop and validate an in vivo screening strategy for identifying synthetic Ras function inhibitors (RFIs).
• To assess the efficacy of potential RFIs, including a synthetic farnesyl substrate analog (AGOH) and related compounds.

Main Methods:

• Utilized a screening strategy monitoring Ras activation via Raf1-GFP translocation to the plasma membrane.
• Assessed phenotypic outputs such as cell polarization, motility, and aggregation during fruiting body formation.
• Confirmed compound incorporation into cellular proteins using western blot analysis.

Main Results:

• Identified m-CN-AGOH as the sole effective inhibitor of Ras activation among the tested compounds.
• Observed impaired cell polarization, motility, and aggregation in cells treated with AGOH and m-CN-AGOH.
• Demonstrated the potential for high-throughput screening using Dictyostelium discoideum and automated microscopy.

Conclusions:

• The developed in vivo screening assays are effective for identifying novel RFIs.
• m-CN-AGOH shows promise as an RFI candidate for further investigation in mammalian systems.
• This approach facilitates the discovery of targeted cancer therapies by inhibiting Ras signaling pathways.