Functional characterization of a PROTAC directed against BRAF mutant V600E PMID: 32778845

ADC Targets in Oncology

2026-04-10

Functional characterization of a PROTAC directed against BRAF mutant V600E

Nat Chem Biol. 2020 Nov;16(11):1170-1178. doi: 10.1038/s41589-020-0609-7.

Ganna Posternak ^# ¹ ² ³ , Xiaojing Tang ^# ¹ , Pierre Maisonneuve ^# ¹ , Ting Jin ^# ⁴ , Hugo Lavoie ^# ⁴ , Salima Daou ¹ , Stephen Orlicky ¹ , Theo Goullet de Rugy ¹ , Lauren Caldwell ¹ , Kin Chan ¹ , Ahmed Aman ² ⁵ , Michael Prakesch ² , Gennady Poda ² ⁵ , Pavel Mader ¹ , Cassandra Wong ¹ , Stefan Maier ¹ , Julia Kitaygorodsky ¹ ⁶ , Brett Larsen ¹ , Karen Colwill ¹ , Zhe Yin ¹ ⁷ , Derek F Ceccarelli ¹ , Robert A Batey ³ , Mikko Taipale ⁶ ⁸ , Igor Kurinov ⁹ , David Uehling ² , Jeff Wrana ¹ ⁶ , Daniel Durocher ¹ ⁶ , Anne-Claude Gingras ¹ ⁶ , Rima Al-Awar ² , Marc Therrien ¹⁰ ¹¹ , Frank Sicheri ¹² ¹³ ¹⁴

Affiliations

1. Center for Molecular, Cell and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.
2. Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario, Canada.
3. Department of Chemistry, University of Toronto, Toronto, Ontario, Canada.
4. Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Quebec, Montreal, Canada.
5. Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
6. Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
7. Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
8. Donnelly Centre for Cellular and Biomolecular Research, Toronto, Ontario, Canada.
9. Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, IL, USA.
10. Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Quebec, Montreal, Canada. [email protected].
11. Département de Pathologie et Biologie Cellulaire, University of Montréal, Quebec, Montreal, Canada. [email protected].
12. Center for Molecular, Cell and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada. [email protected].
13. Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada. [email protected].
14. Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada. [email protected].
# Contributed equally.

Abstract

The Raf family kinases function in the RAS-ERK pathway to transmit signals from activated Ras to the downstream kinases MEK and ERK. This pathway regulates cell proliferation, differentiation and survival, enabling mutations in Ras and Raf to act as potent drivers of human cancers. Drugs targeting the prevalent oncogenic mutant BRAF(V600E) have shown great efficacy in the clinic, but long-term effectiveness is limited by resistance mechanisms that often exploit the dimerization-dependent process by which Raf kinases are activated. Here, we investigated a proteolysis-targeting chimera (PROTAC) approach to BRAF inhibition. The most effective PROTAC, termed P4B, displayed superior specificity and inhibitory properties relative to non-PROTAC controls in BRAF(V600E) cell lines. In addition, P4B displayed utility in cell lines harboring alternative BRAF mutations that impart resistance to conventional BRAF inhibitors. This work provides a proof of concept for a substitute to conventional chemical inhibition to therapeutically constrain oncogenic BRAF.