BAP1 links epigenetic regulation of ferroptosis to tumor suppression

Compared to the well-established roles of apoptosis in tumor suppression, the roles and regulatory mechanisms of ferroptosis, a non-apoptotic form of cell death, in tumor biology remain much less understood. BRCA1-associated protein 1 (BAP1) encodes a nuclear de-ubiquitinating (DUB) enzyme to reduce histone 2A ubiquitination (H2Aub) on chromatin, and is a tumor suppressor in several human cancers. Here, integrated transcriptomic, epigenomic, and cancer genomic analyses link BAP1 to metabolism-related biological processes, including oxidative stress response, and identify cystine transporter SLC7A11 as a BAP1-repressed target gene with high relevance to BAP1-mediated tumor suppression in human cancers. Functional studies reveal that BAP1, in a DUB-dependent manner, decreases H2Aub occupancy on the SLC7A11 promoter and represses SLC7A11 expression, and that BAP1 inhibits cystine uptake and promotes ferroptosis through repressing SLC7A11 expression. Finally, we show that BAP1 inhibits tumor development partly through SLC7A11, and that cancer-associated BAP1 mutants lose their abilities to repress SLC7A11 and to promote ferroptosis. Together, the results of our study show that BAP1 executes its tumor suppression function at least partly through its regulation of SLC7A11 and ferroptosis, and uncover a previously unappreciated mechanism coupling ferroptosis to tumor suppression. ChIP-seq of H2AK119ub was applied in UMRC6 EV, BAP1 WT and C91A cells