Download MendeleyIdentification of a Highly Cooperative PROTAC Degrader Targeting GTP-Loaded KRAS(On) Alleles.
Vetma, V., Puoti, I., Karolak, N.K., Chakraborti, S., Diers, E., Girardi, E., Khan, S., Kidd, G., Kropatsch, K.G., Mclennan, R., O'Connor, S., Samwer, M., Trainor, N., Whitworth, C., Wijaya, A.J., Wong, J.Y.F., Zollman, D., Farnaby, W., Popow, J., Ciulli, A., Ettmayer, P., McAulay, K.(2025) J Am Chem Soc
- PubMed: 41166656
- DOI: https://doi.org/10.1021/jacs.5c10354
- Primary Citation of Related Structures:
9RK8, 9RKC, 9RKE, 9RKJ, 9RKN - PubMed Abstract:
Kirsten rat sarcoma viral oncogene homologue (KRAS) is a frequently mutated oncogene in multiple types of cancer and is a high priority target for oncology drug development. There are many different KRAS mutations, including mutations that favor the GTP-loaded hydrolysis-incompetent "active" state of KRAS, KRAS(on), that can lead to tumorigenesis. However, small molecule interventions thus far have predominantly targeted single mutations of "inactive" GDP-loaded KRAS, KRAS(off), such as KRAS G12C . Here, we address this gap through the development of heterobifunctional VHL-based PROTACs capable of engaging and degrading KRAS(on), thus addressing a wider range of KRAS mutations. By studying ternary complex affinity, stability, and binding modes using SPR and X-ray cocrystal structures, we identified PROTACs that exhibit high positive cooperativity in forming ternary complexes with VHL and GCP-loaded KRAS as representative of KRAS(on) variants. Degrader activity profiling in relevant cancer cells supported the discovery of ACBI4, a PROTAC which forms a highly stable and cooperative ternary complex between VHL and GTP-bound KRAS and which potently degrades KRAS G12R , leading to antiproliferative effect in KRAS mutant-driven cancer cells. ACBI4 provides a new chemical tool for studying the impact of degrading KRAS(on) mutants, which is not possible with current pan-KRAS inhibitors or degraders.
- Centre for Targeted Protein Degradation, School of Life Sciences, University of Dundee, 1 James Lindsay Place, DD1 5JJ Dundee, Scotland, U.K.
Organizational Affiliation:
