Law Mary E, Dulloo Zaafir M, Eggleston Samantha R, Takacs Gregory P, Alexandrow Grace M, Lee Young Il, Wang Mengxiong, Hardy Brian, Su Hanyu, Forsyth Bianca, Das Parag, Datta Pran K, Chiang Chi-Wu, Sharma Abhisheak, Kanumuri Siva Rama Raju, Guryanova Olga A, Harrison Jeffrey K, Tirosh Boaz, Castellano Ronald K, Law Brian K
University of Florida, Gainesville, FL, United States.
University of Florida, United States.
Mol Cancer Res. 2024 Mar 19. doi: 10.1158/1541-7786.MCR-24-0756.
New agents are needed that selectively kill cancer cells without harming normal tissues. The TRAIL ligand and its receptors, DR5 and DR4, exhibit cancer-selective toxicity. TRAIL analogs or agonistic antibodies targeting these receptors are available but have not yet received FDA approval for cancer therapy. Small molecules for activating DR5 or DR4 independently of protein ligands may activate TRAIL receptors as a monotherapy or potentiate the efficacy of TRAIL analogs and agonistic antibodies. Previously described Disulfide bond Disrupting Agents (DDAs) activate DR5 by altering its disulfide bonding through inhibition of the Protein Disulfide Isomerases (PDIs) ERp44, AGR2, and PDIA1. Work presented here extends these findings by showing that disruption of single DR5 disulfide bonds causes high-level DR5 expression, disulfide-mediated clustering, and activation of Caspase 8-Caspase 3 mediated pro-apoptotic signaling. Recognition of the extracellular domain of DR5 by various antibodies is strongly influenced by the pattern of DR5 disulfide bonding, which has important implications for the use of agonistic DR5 antibodies for cancer therapy and as research tools. Importantly, other ER stressors, including Thapsigargin and Tunicamycin also alter DR5 disulfide bonding in various cancer cell lines and in some instances, DR5 mis-disulfide bonding is potentiated by overriding the Integrated Stress Response (ISR) with inhibitors of the PERK kinase or the ISR inhibitor ISRIB. These observations indicate that the pattern of DR5 disulfide bonding functions as a sensor of ER stress and serves as an effector of proteotoxic stress by driving extrinsic apoptosis independently of extracellular ligands. Implications: Extreme endoplasmic reticulum stress triggers triage of transmembrane receptor production, whereby mitogenic receptors are downregulated and death receptors are simultaneously elevated.
需要能够选择性杀死癌细胞而不损害正常组织的新型药物。肿瘤坏死因子相关凋亡诱导配体（TRAIL）及其受体DR5和DR4具有癌症选择性毒性。针对这些受体的TRAIL类似物或激动性抗体已存在，但尚未获得美国食品药品监督管理局（FDA）批准用于癌症治疗。能够独立于蛋白质配体激活DR5或DR4的小分子，可作为单一疗法激活TRAIL受体，或增强TRAIL类似物和激动性抗体的疗效。先前描述的二硫键破坏剂（DDA）通过抑制蛋白质二硫键异构酶（PDI）ERp44、AGR2和PDIA1来改变DR5的二硫键，从而激活DR5。本文的研究扩展了这些发现，表明破坏单个DR5二硫键会导致DR5高水平表达、二硫键介导的聚集以及半胱天冬酶8-半胱天冬酶3介导的促凋亡信号激活。各种抗体对DR5胞外域的识别受DR5二硫键模式的强烈影响，这对于将激动性DR5抗体用于癌症治疗和作为研究工具具有重要意义。重要的是，其他内质网应激源，包括毒胡萝卜素和衣霉素，也会改变各种癌细胞系中DR5的二硫键，在某些情况下，通过用PERK激酶抑制剂或内质网应激反应抑制剂ISRIB override整合应激反应（ISR），DR5的错误二硫键结合会增强。这些观察结果表明，DR5二硫键模式作为内质网应激的传感器，并通过独立于细胞外配体驱动外源性凋亡，作为蛋白毒性应激的效应器。启示：极端内质网应激触发跨膜受体产生的分类，有丝分裂受体下调，而死亡受体同时升高。
