Dual targeting of BRAF(V600E) and ferroptosis results in synergistic anticancer activity via iron overload and enhanced oxidative stress.

BACKGROUND: While combination BRAF and MEK inhibitor treatment in BRAF(V600E)-mutant cancers results in a response, treatment resistance and toxicity are common. Ferroptosis is an iron-dependent form of non-apoptotic cell death. BRAF inhibition has been associated with increased sensitivity to ferroptosis that is dependent on Glutathione Peroxidase 4 (GPX4). METHODS: In vitro, ex vivo, and in vivo models of anaplastic thyroid cancer (ATC) were used to evaluate the anticancer activity of combination BRAF inhibition and ferroptosis induction. RESULTS: Targeting key regulators of ferroptosis—GPX4, using RSL3 and ML162, and system X(c)(−), using erastin—induced significant cell death in all ATC cell lines. Combination of dabrafenib and RSL3 synergistically increased cell death in BRAF(V600E)-mutant ATC cells, and significantly inhibited colony formation. Mechanistically, lipid peroxidation, reactive oxygen species levels, and intracellular Fe(2+) increased significantly with combination treatment compared with each agent alone. Analysis of cell membrane iron importers and exporters showed significantly lower expression of ferroportin-1 (an iron exporter), suggesting the synergistic anticancer activity was due to increased iron accumulation and oxidative stress, leading to enhanced ferroptotic cell death. BRAF(V600E)-mutant ATC cell spheroids showed synergistic cell death with dabrafenib and RSL3 treatment. In vivo, combination dabrafenib and ferroptosis induction (by targeting GPX4 using C18, and system X(c)(−) with IKE) significantly inhibited tumor growth in an orthotopic ATC mouse model. Additionally, dabrafenib-resistant BRAF(V600E)-mutant ATC cells were more sensitive to ferroptosis induction than parental cells. CONCLUSIONS: Dual targeting of BRAFV600E and ferroptosis results in synergistic anticancer activity and overcomes resistance to BRAF inhibition. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13046-025-03624-z.