Down-regulation of glucose-regulated protein (GRP) 78 potentiates cytotoxic effect of celecoxib in human urothelial carcinoma cells
Journal
PLoS ONE
Journal Volume
7
Journal Issue
3
Pages
e33615
Date Issued
2012
Author(s)
Kuo K.-L.
Chen S.-C.
Chuang Y.-T.
Liu S.-H.
Abstract
Celecoxib is a selective cyclooxygenase-2 (COX-2) inhibitor that has been reported to elicit anti-proliferative response in various tumors. In this study, we aim to investigate the antitumor effect of celecoxib on urothelial carcinoma (UC) cells and the role endoplasmic reticulum (ER) stress plays in celecoxib-induced cytotoxicity. The cytotoxic effects were measured by MTT assay and flow cytometry. The cell cycle progression and ER stress-associated molecules were examined by Western blot and flow cytometry. Moreover, the cytotoxic effects of celecoxib combined with glucose-regulated protein (GRP) 78 knockdown (siRNA), (-)-epigallocatechin gallate (EGCG) or MG132 were assessed. We demonstrated that celecoxib markedly reduces the cell viability and causes apoptosis in human UC cells through cell cycle G1 arrest. Celecoxib possessed the ability to activate ER stress-related chaperones (IRE-1α and GRP78), caspase-4, and CCAAT/enhancer binding protein homologous protein (CHOP), which were involved in UC cell apoptosis. Down-regulation of GRP78 by siRNA, co-treatment with EGCG (a GRP78 inhibitor) or with MG132 (a proteasome inhibitor) could enhance celecoxib-induced apoptosis. We concluded that celecoxib induces cell cycle G1 arrest, ER stress, and eventually apoptosis in human UC cells. The down-regulation of ER chaperone GRP78 by siRNA, EGCG, or proteosome inhibitor potentiated the cytotoxicity of celecoxib in UC cells. These findings provide a new treatment strategy against UC. ? 2012 Huang et al.
SDGs
Other Subjects
3 (4,5 dimethyl 2 thiazolyl) 2,5 diphenyltetrazolium bromide; benzyloxycarbonylleucylleucylleucinal; caspase 4; CCAAT enhancer binding protein; CCAAT enhancer binding protein homologous protein; celecoxib; chaperone; epigallocatechin gallate; glucose regulated protein 78; protein IRE 1alpha; small interfering RNA; unclassified drug; benzyloxycarbonylleucyl leucyl leucine aldehyde; benzyloxycarbonylleucyl-leucyl-leucine aldehyde; catechin; celecoxib; cyclooxygenase 2 inhibitor; drug derivative; epigallocatechin gallate; heat shock protein; indole derivative; leupeptin; LM 1685; LM-1685; molecular chaperone GRP78; pyrazole derivative; small interfering RNA; sulfonamide; apoptosis; article; cancer cell culture; cell assay; cell cycle arrest; cell cycle G1 phase; cell cycle progression; cell viability; controlled study; cytotoxicity; down regulation; drug potentiation; drug targeting; endoplasmic reticulum stress; flow cytometry; human; human cell; transitional cell carcinoma; Western blotting; bladder tumor; cell survival; down regulation; drug antagonism; drug effect; drug potentiation; endoplasmic reticulum; G1 phase cell cycle checkpoint; genetics; metabolism; pathology; physiological stress; tumor cell line; unfolded protein response; Apoptosis; Catechin; Cell Line, Tumor; Cell Survival; Cyclooxygenase 2 Inhibitors; Down-Regulation; Drug Synergism; Endoplasmic Reticulum; G1 Phase Cell Cycle Checkpoints; Heat-Shock Proteins; Humans; Indoles; Leupeptins; Pyrazoles; RNA, Small Interfering; Stress, Physiological; Sulfonamides; Unfolded Protein Response; Urinary Bladder Neoplasms
Type
journal article