Targeting the IRE1a/XBP1 endoplasmic reticulum stress response pathway in ARID1Amutant ovarian cancers

xenograft, patientderived xenograft and the genetic Arid1aflox/flox/Pik3caH1047R mouse models. Finally, B-I09 synergizes with inhibition of HDAC6, a known regulator of the ER stress response, in suppressing the growth of ARID1A-inactivated OCCCs. These studies reveal a promising therapeutic strategy for ARID1A-mutant OCCCs and define the IRE1?-XBP1 axis of the ER stress response as a targetable vulnerability for ARID1A-mutant OCCCs. Our findings indicate that pharmacological inhibition of the IRE1?-XBP1 pathway alone or in combination with HDAC6 inhibition represents an urgently needed therapeutic strategy for ARID1A-mutant ovarian cancers. Overall design: RNA-seq experiment in ARID1A WT and KO cells under control and tunicamycin treatment