ERX-41

ERX-41 is an inducer of endoplasmic reticulum (ER) stress.¹ It increases the thermal stability of lysosomal acid lipase when used at a concentration of 10 µM in the cellular thermal shift assay (CETSA) but does not inhibit lysosomal acid lipase enzymatic activity at 30 µM. ERX-41 (1 µM) increases ER tubule width, eukaryotic translation initiation factor 2α kinase 3 (EIF2AK3/PERK) and inositol-requiring enzyme 1α (IRE1α) phosphorylation, and splicing of the gene encoding X-box binding protein 1 (XBP1) in SUM149 triple-negative breast cancer (TNBC) cells. It reduces tumor volume and weight in several patient-derived xenograft (PDX) mouse models of TNBC when administered at a dose of 10 mg/kg.