Abstract
ARID1A encodes an SWI/SNF chromatin-remodeling factor and is frequently mutated in various cancers. This study demonstrates that ARID1A-deficient cancer cells are specifically vulnerable to inhibition of the antioxidant glutathione (GSH) and the glutamate-cysteine ligase synthetase catalytic subunit (GCLC), a rate-limiting enzyme for GSH synthesis. Inhibition of GCLC markedly decreased GSH in ARID1A-deficient cancer cells, leading to apoptotic cell death triggered by excessive amounts of reactive oxygen species. The vulnerability of ARID1A-deficient cancer cells results from low basal levels of GSH due to impaired expression of SLC7A11. The SLC7A11-encoded cystine transporter supplies cells with cysteine, a key source of GSH, and its expression is enhanced by ARID1A-mediated chromatin remodeling. Thus, ARID1A-deficient cancers are susceptible to synthetic lethal targeting of GCLC.