Mutant-selective degradation by BRAF-targeting PROTACs Journal Article


Authors: Alabi, S.; Jaime-Figueroa, S.; Yao, Z.; Gao, Y.; Hines, J.; Samarasinghe, K. T. G.; Vogt, L.; Rosen, N.; Crews, C. M.
Article Title: Mutant-selective degradation by BRAF-targeting PROTACs
Abstract: Over 300 BRAF missense mutations have been identified in patients, yet currently approved drugs target V600 mutants alone. Moreover, acquired resistance inevitably emerges, primarily due to RAF lesions that prevent inhibition of BRAF V600 with current treatments. Therefore, there is a need for new therapies that target other mechanisms of activated BRAF. In this study, we use the Proteolysis Targeting Chimera (PROTAC) technology, which promotes ubiquitination and degradation of neo-substrates, to address the limitations of BRAF inhibitor-based therapies. Using vemurafenib-based PROTACs, we achieve low nanomolar degradation of all classes of BRAF mutants, but spare degradation of WT RAF family members. Our lead PROTAC outperforms vemurafenib in inhibiting cancer cell growth and shows in vivo efficacy in a Class 2 BRAF xenograft model. Mechanistic studies reveal that BRAFWT is spared due to weak ternary complex formation in cells owing to its quiescent inactivated conformation, and activation of BRAFWT sensitizes it to degradation. This study highlights the degree of selectivity achievable with degradation-based approaches by targeting mutant BRAF-driven cancers while sparing BRAFWT, providing an anti-tumor drug modality that expands the therapeutic window. © 2021, The Author(s).
Keywords: molecular analysis; biochemistry; inhibition; drug; cell component; cancer; growth response
Journal Title: Nature Communications
Volume: 12
ISSN: 2041-1723
Publisher: Nature Publishing Group  
Date Published: 2021-02-10
Start Page: 920
Language: English
DOI: 10.1038/s41467-021-21159-7
PUBMED: 33568647
PROVIDER: scopus
PMCID: PMC7876048
DOI/URL:
Notes: Article -- Export Date: 1 April 2021 -- Source: Scopus
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  1. Neal Rosen
    425 Rosen
  2. Zhan Yao
    38 Yao
  3. Yijun   Gao
    11 Gao