Class II ferroptosis inducers are a novel therapeutic approach for t(4;14)-positive multiple myeloma.

Multiple myeloma (MM) is a clonal plasma cell malignancy that is characterized by genetic heterogeneity. The cytogenetic abnormality t(4;14) strongly predicts poor outcome in patients with MM, even in the era of novel drugs. Ferroptosis is a new approach to antitumor therapy, but the relationship between ferroptosis and MM cytogenetic abnormalities remains largely unclear. In this study, we show that t(4;14)-positive but not t(4;14)-negative MM cells are susceptible to class II ferroptosis inducers (FINs) in a preclinical setting, which is dependent on the significant upregulation of the MM SET domain-containing protein (MMSET). Mechanistically, MMSET upregulates acyl-coenzyme A synthetase long-chain family member 4 transcription by binding to its promoter region, leading to increased polyunsaturated fatty acid (PUFA) levels and enhanced sensitivity of t(4;14)-positive MM cells to ferroptosis. Supplementation with PUFAs efficiently restores the susceptibility of t(4;14)-negative MM cells to ferroptosis. In addition, combining class II FIN treatment with bortezomib in t(4;14)-positive MM cells attenuates cellular glutathione and induces both apoptosis and ferroptosis levels by inhibiting the increase in solute carrier family 7 member 11, demonstrating synergistic antitumor activity in vitro and in a xenograft model. Taken together, our findings suggest that targeting ferroptosis with class II FINs is a novel and promising therapeutic approach to improve the outcome of t(4;14)-positive patients with MM.