Efficacy of glutathione inhibitors for the treatment of ARID1A-deficient diffuse-type gastric cancers

ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, increases the intracellular levels of glutathione (GSH) by upregulating solute carrier family 7 member 11 (SLC7A11). Diffuse-type gastric cancer is an aggressive tumor that is frequently associated with ARID1A deficiency. Here, we investigated the efficacy of GSH inhibition for the treatment of diffuse-type gastric cancer with ARID1A deficiency using ARID1A-proficient or -deficient patient-derived cells (PDCs). ARID1A-deficient PDCs were selectively sensitive to the GSH inhibitor APR-246, the GCLC inhibitor buthionine sulfoximine, and the SLC7A11 inhibitor erastin. Expression of SLC7A11, which is required for incorporation of cystine, and the basal level of GSH were lower in ARID1A-deficient than in ARID1A-proficient PDCs. Treatment with APR-246 decreased intracellular GSH levels, leading to the excessive production of reactive oxygen species (ROS), and these phenotypes are suppressed by supply of cystine and GSH compensators. Taken together, vulnerability of ARID1A-deficient gastric cancer cells to GSH inhibition is caused by decreased GSH synthesis due to diminished SLC7A11 expression. The present results suggest that GSH inhibition is a promising strategy for the treatment of diffuse-type gastric cancers with ARID1A deficiency.