title: Epigallocatechin-3-gallate suppressed the over-expression of HSP 70 and MDR1 induced by heat shock in SGC 7901.
abstract: This study investigated the effects of epigallocatechin-3-gallate (EGCG) on the expression of HSP 70 and MDR 1. SGC-7901 cells were cultured with RPMI 1640 medium. The single or combined effects of EGCG (0.1, 1, 10, 20, and 40 micromol/L) and heat shock were examined by MTT assay. The expression of HSP 70 and MDR 1 was semi-quantified by the reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry method (SP staining). EGCG suppressed cell proliferation at a time- and dose-dependent manner. The effects of combined treatment with EGCG and heat shock on the growth of SGC-7901 cells were stronger than single effects of EGCG. After using EGCG for 24 h, 48 h and 72 h, the IC50s were 112.5 micromol/l, 21.41 micromol/l and 5.24 micromol/l, respectively. Heat shock stimulated the over-expression of HSP 70, especially after heat shock for 8 h, as well as MDR1 after heat shock for 24 h. But EGCG suppressed the over-expression induced by heat shock. The authors conclude that EGCG inhibited the proliferation of SGC-7901, and EGCG combined with heat shock strengthened the effects. Heat shock weakened the over-expression of HSP 70 and MDR1; however, EGCG suppressed the over-expression of HSP 70 and MDR1 induced by heat shock. EGCG combined with heat shock may enhance the sensitivity of drugs to tumors.
authors.affiliation: Department of Gastroenterology, Zhongnan Hospital of Wuhan University, Wuhan, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Tang
authors.forename: You-Qing
authors.initials: YQ
authors.lastname: Zhu
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature; D006801:Humans; D012333:RNA, Messenger / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D016588:Anticarcinogenic Agents; D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger; D002392:Catechin; C045651:epigallocatechin gallate