title: Proteomic approaches to study epigallocatechin gallate-provoked apoptosis of TSGH-8301 human urinary bladder carcinoma cells: roles of AKT and heat shock protein 27-modulated intrinsic apoptotic pathways.
abstract: Epigallocatechin-3-gallate (EGCG), a polyphenol constituent present in green tea, has been shown to inhibit the growth of cancer cells in vitro and in vivo. However, studies regarding human bladder carcinoma cells are limited and not well investigated. Hence, our study focused on the evaluation of EGCG-triggered apoptosis in TSGH-8301 human urinary bladder carcinoma cells in vivo and in vitro as well as its related molecular mechanisms. In an in vivo study, EGCG inhibited xenograft tumor size of TSGH-8301 cells in a nude mouse model. Based on an in vitro study, EGCG resulted in morphological changes and increased growth inhibition in a dose- and time-dependent manner in TSGH-8301 cells. Furthermore, sub-G1 populations were shown and caspase-9 and -3 activities were stimulated in EGCG-treated TSGH-8301 cells. Moreover, a caspase-9 inhibitor (Z-LEHD-FMK) and a caspase-3 inhibitor (Z-DEVD-FMK) were able to reduce EGCG-stimulated caspase-9 and -3 activities, respectively. Loss of mitochondrial membrane potential (∆Ψm) resulted in an increase of protein levels of cytochrome c, Apaf-1, caspase-9 and -3 in TSGH-8301 cells following exposure to EGCG. Proteomic analysis revealed that EGCG affected the expression levels of various proteins, including HSP27, porin, tropomyosin 3 isoform 2, prohibitin and keratin 5, 14, 17 in TSGH-8301 cells. EGCG also suppressed AKT kinase activity and protein levels and also altered the expression levels of Bcl-2 family-related proteins such as Bcl-2, Bax, BAD and p-BAD. Based on the above findings, this study suggests that EGCG-provoked apoptotic death in TSGH-8301 cells is mediated through targeting AKT and HSP27 and modulating p-BAD, leading to activation of the intrinsic apoptotic pathway.
authors: Department of Veterinary Medicine, National Chung Hsing University, and Department of Radiology, China Medical University Hospital, Taichung 402, Taiwan, ROC.
authors: Nian-Gu
authors: NG
authors: Chen
authors: Chi-Cheng
authors: CC
authors: Lu
authors: Yu-Hsin
authors: YH
authors: Lin
authors: Wu-Chung
authors: WC
authors: Shen
authors: Cheng-Hung
authors: CH
authors: Lai
authors: Yung-Jen
authors: YJ
authors: Ho
authors: Jing-Gung
authors: JG
authors: Chung
authors: Tsai-Hsiu
authors: TH
authors: Lin
authors: Yung-Chang
authors: YC
authors: Lin
authors: Jai-Sing
authors: JS
authors: Yang
mesh_terms: D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D055551:HSP27 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D040901:Proteomics / Q000379:methods; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D011897:Random Allocation; D001749:Urinary Bladder Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D023041:Xenograft Model Antitumor Assays
chemical_list: D016588:Anticarcinogenic Agents; D055551:HSP27 Heat-Shock Proteins; D002392:Catechin; C045651:epigallocatechin gallate; D051057:Proto-Oncogene Proteins c-akt