Personalized targeting of BCL2 family proteins overcomes acquired resistance to BRAF-MEK inhibitors in preclinical melanoma.

Y N, Vashisht Gopal; de Groot, Evelyn; Loftin, Kaley; Knighton, Barbara; Ledesma, Debora; Hudgens, Courtney; Shamsutdinova, Diana; Ali, Mehboob et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

There are currently no effective targeted therapies for BRAF-mutant metastatic melanoma patients with acquired resistance to approved BRAF and MEK inhibitors (BRAFi and MEKi), and very few ongoing clinical trials. Anti-apoptotic BCL2 family proteins promote de novo resistance to several therapies, including single-agent BRAFi in BRAF-mutant melanomas. In this study, in vivo testing of a large collection of patient-derived xenograft (PDX) models from melanoma patients with acquired resistance to BRAFi or BRAFi+MEKi shows that combining BCL2 inhibitors (BCL2i; navitoclax or venetoclax) with BRAFi+MEKi induces tumor regressions in a subset of these PDXs. High basal BCL2 predicts response whereas high basal MCL1 predicts resistance to this strategy. MCL1 overexpression studies functionally validate its role in resistance. Further, combining BRAFi+MEKi with an MCL1 inhibitor (MCL1i) counteracts resistance and interestingly decreases MCL1i-associated markers of cardiotoxicity. Together these studies identify potential personalized strategies to improve outcomes in this challenging patient population.