The α6β4 integrin promotes resistance to ferroptosis

Increases in lipid peroxidation can cause ferroptosis, a form of cell death triggered by inhibition of glutathione peroxidase 4 (GPX4), which catalyzes the reduction of lipid peroxides and is a target of ferroptosis inducers, such as erastin. The α6β4 integrin protects adherent epithelial and carcinoma cells from ferroptosis induced by erastin. In addition, extracellular matrix (ECM) detachment is a physiologic trigger of ferroptosis, which is evaded by α6β4. The mechanism that enables α6β4 to evade ferroptosis involves its ability to protect changes in membrane lipids that are proferroptotic. Specifically, α6β4-mediated activation of Src and STAT3 suppresses expression of ACSL4, an enzyme that enriches membranes with long polyunsaturated fatty acids and is required for ferroptosis. Adherent cells lacking α6β4 require an inducer, such as erastin, to undergo ferroptosis because they sustain GPX4 expression, despite their increase in ACSL4. In contrast, ECM detachment of cells lacking α6β4 is sufficient to trigger ferroptosis because GPX4 is suppressed. This causal link between α6β4 and ferroptosis has implications for cancer biology and therapy.