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bioRxiv · 10.1101/2024.09.18.613772

Uncovering the mechanistic basis of intracellular Raf inhibitor sensitivity reveals synergistic cotreatment strategies

Stoddard, E. G.·Fang, L.·Zhong, Y.·Potter, Z. E.·Brush, D. S.·Simon, J. J.·Golkowski, M.·Maly, D. J.
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Abstract

Raf kinases are crucial effectors in the Ras-Raf-Mek-Erk signaling pathway, making them important targets for the development of cancer therapeutics. This study investigates the variable potency of DFG-out-stabilizing Raf inhibitors in mutant KRas-expressing cell lines. We demonstrate that inhibitor potency correlates with basal Raf activity, with more active Raf being more susceptible to inhibition. We further show that DFG-out-stabilizing inhibitors disrupt high-affinity Raf-Mek interactions, promoting the formation of inhibited Raf dimers. Furthermore, we identify cobimetinib as a Mek inhibitor that uniquely sensitizes Raf to DFG-out inhibitors by disrupting autoinhibited Raf-Mek complexes. Building on this insight, we developed cobimetinib analogs with enhanced sensitization properties. Our findings provide a mechanistic framework for understanding the cellular determinants of DFG-out-stabilizing inhibitor sensitivity and offer strategies for optimizing synergistic Raf-Mek inhibitor combinations.

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Stoddard, E. G., Fang, L., Zhong, Y., Potter, Z. E., Brush, D. S., Simon, J. J., Golkowski, M., Maly, D. J.. 2024-09-19. Uncovering the mechanistic basis of intracellular Raf inhibitor sensitivity reveals synergistic cotreatment strategies. https://doi.org/10.1101/2024.09.18.613772

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