Identification of Small-Molecule Inhibitors that Block the GTP-Binding Pocket of K-Ras and Other Members of the Ras Superfamily of Small GTPases

  • Mol Cancer Ther. 2025 Sep 12:OF1-OF10. doi: 10.1158/1535-7163.MCT-24-0618.
Luca Carta  #  1 ,  Rebecca Hutcheson  #  1 ,  Carolina L Bigarella  1 ,  Sufang Zhang  1 ,  Simon A Davis  2 ,  Michael J Rudolph  2 ,  Charles H Reynolds  3 ,  Matthias Quick  4  5  6 ,  Theresa M Williams  7 ,  Michael Schmertzler  1 ,  Yaron R Hadari  1
Affiliations
  • 1. SHY Therapeutics, LLC, Valhalla, New York.
  • 2. New York Structural Biology Center, New York, New York.
  • 3. GFree Bio, LLC, Austin, Texas.
  • 4. Department of Psychiatry, Columbia University Vagelos College of Physicians and Surgeons, New York, New York.
  • 5. Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, New York.
  • 6. Area Neuroscience - Molecular Therapeutics, New York State Psychiatric Institute, New York, New York.
  • 7. Wise Consulting, LLC, Harleysville, Pennsylvania.
  • # Contributed equally.
PMID: 40936333 DOI: 10.1158/1535-7163.MCT-24-0618
Abstract

Ras genes encode small GTPases essential for mammalian cell proliferation, differentiation, and survival. Ras gene mutations are associated with 20% to 30% of all human cancers. Based on earlier reports of extremely high Ras binding affinities for GTP, Ras proteins were previously considered undruggable. Using three independent techniques, we report binding affinities of K-Ras and several K-Ras mutants for GTP in the 250 to 400 nmol/L range, orders of magnitude lower than previously reported (∼10 pmol/L). This discovery suggests that K-Ras and Other small-GTPase proteins may indeed be druggable targets. We identified more than 400 small molecules that compete non-covalently with GTP binding to K-Ras. Focusing on two inhibitors, we demonstrate the inhibition of K-Ras in downstream signaling and cellular proliferation in human pancreatic and non-small cell lung Cancer cells expressing wild-type or mutant K-Ras. These two compounds represent novel pan-Ras superfamily inhibitors as they also inhibited GTP binding to Other members such as RAB5A and RAB35.

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