TY - JOUR T1 - Inhibitors of ERp44, PDIA1, and AGR2 induce disulfide-mediated oligomerization of Death Receptors 4 and 5 and cancer cell death JF - bioRxiv DO - 10.1101/2021.01.13.426390 SP - 2021.01.13.426390 AU - Mary E. Law AU - Elham Yaaghubi AU - Amanda F. Ghilardi AU - Bradley J. Davis AU - Renan B. Ferreira AU - Jin Koh AU - Sixue Chen AU - Sadie F. DePeter AU - Christopher M. Schilson AU - Chi-Wu Chiang AU - Coy D. Heldermon AU - Peter Nørgaard AU - Ronald K. Castellano AU - Brian K. Law Y1 - 2021/01/01 UR - http://biorxiv.org/content/early/2021/08/13/2021.01.13.426390.abstract N2 - Breast cancer mortality remains unacceptably high, indicating a need for safer and more effective therapeutic agents. Disulfide bond Disrupting Agents (DDAs) were previously identified as a novel class of anticancer compounds that selectively kill cancers that overexpress the Epidermal Growth Factor Receptor (EGFR) or its family member HER2. DDAs kill EGFR+ and HER2+ cancer cells via the parallel downregulation of EGFR, HER2, and HER3 and activation/oligomerization of Death Receptors 4 and 5 (DR4/5). However, the mechanisms by which DDAs mediate these effects are unknown. Affinity purification analyses employing biotinylated-DDAs reveal that the Protein Disulfide Isomerase (PDI) family members AGR2, PDIA1, and ERp44 are DDA target proteins. Further analyses demonstrate that shRNA-mediated knockdown of AGR2 and ERp44, or expression of ERp44 mutants, alter basal and DDA-induced DR5 oligomerization. DDA treatment of breast cancer cells disrupts PDIA1 and ERp44 mixed disulfide bonds with their client proteins. Together, these results reveal DDAs as the first small molecule, active site inhibitors of AGR2 and ERp44, and demonstrate roles for AGR2 and ERp44 in regulating the activity, stability, and localization of DR4 and DR5, and activation of Caspase 8.Competing Interest StatementThe authors have declared no competing interest. ER -