title: Retrovirus-mediated transduction of a short hairpin RNA gene for GRP78 fails to downregulate GRP78 expression but leads to cisplatin sensitization in HeLa cells.
abstract: Glucose-regulated protein 78 (GRP78) is expressed abundantly in various types of cancer cells and is believed to contribute to chemotherapeutic resistance. In this study, we investigated the effect of a continuous approach for the expression of a short hairpin RNA (shRNA) targeted to GRP78 with retrovirus transduction on the sensitivity to the anticancer drugs VP-16 and cisplatin. The reduction of GRP78 expression failed, and the expression of GRP94 and P5 chaperon mRNA increased; this increase was associated with a mild activation of the unfolded protein response in HeLa cells, which were stably transduced with GRP78 shRNA gene. The transduced cells exhibited similar sensitivity to VP-16-induced cell death when compared to control GFP shRNA gene-transduced cells. However, sensitivity to cisplatin-induced cell death was higher in GRP78 shRNA gene-transduced cells compared to control cells. These results demonstrate that the continuous or prolonged approach targeting GRP78 confers sensitization of HeLa cells to cisplatin independently of the down-regulation of GRP78 expression. The role of the unfolded protein response in sensitization to cisplatin is discussed.
authors.affiliation: Department of Health and Nutrition, Wayo Women's University, 2-3-1 Konodai, Ichikawa, Chiba 272-8533, Japan. t-suzuki@wayo.ac.jp
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Suzuki
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Hu
authors.forename: Kazuko
authors.initials: K
authors.lastname: Kita
authors.forename: Nobuo
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D001483:Base Sequence; D002478:Cells, Cultured; D002945:Cisplatin / Q000627:therapeutic use*; D003131:Combined Modality Therapy; D015536:Down-Regulation / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects / Q000235:genetics*; D000091342:Endoplasmic Reticulum Chaperone BiP; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D034741:RNA, Small Interfering / Q000235:genetics*; D012190:Retroviridae / Q000235:genetics / Q000502:physiology
chemical_list: D000970:Antineoplastic Agents; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D034741:RNA, Small Interfering; D002945:Cisplatin