thapsigargin and Esophageal-Neoplasms

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent for esophageal squamous cell carcinoma (ESCC). Forced expression of CHOP, one of the key downstream transcription factors during endoplasmic reticulum (ER) stress, upregulates the death receptor 5 (DR5) levels and promotes oxidative stress and cell death. In this study, we show that ER stress mediated by thapsigargin promoted CHOP and DR5 synthesis thus sensitizing TRAIL treatment, which induced ESCC cells apoptosis. These effects were reversed by DR5 siRNA in vitro and CHOP siRNA both in vitro and in vivo. Besides, chemically inhibition of AMPK by Compound C and AMPK siRNA weakened the anti-cancer effect of thapsigargin and TRAIL co-treatment. Therefore, our findings suggest ER stress effectively sensitizes human ESCC to TRAIL-mediated apoptosis via the TRAIL-DR5-AMPK signaling pathway, and that activation of ER stress may be beneficial for improving the efficacy of TRAIL-based anti-cancer therapy.

Topics: AMP-Activated Protein Kinases; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Survival; Drug Synergism; Drug Therapy, Combination; Endoplasmic Reticulum Stress; Enzyme Activation; Esophageal Neoplasms; Esophageal Squamous Cell Carcinoma; Humans; Neoplasm Invasiveness; Reactive Oxygen Species; Receptors, TNF-Related Apoptosis-Inducing Ligand; RNA, Small Interfering; Thapsigargin; TNF-Related Apoptosis-Inducing Ligand; Transcription Factor CHOP; Up-Regulation