title: Survivin knockdown enhances gastric cancer cell sensitivity to radiation and chemotherapy in vitro and in nude mice.
abstract: BACKGROUND
  The aim is to assess the effect of survivin knockdown on the radio- and chemosensitivity of gastric cancer cells in vitro and in nude mice.
  
  
  METHODS
  Survivin messenger RNA and protein were detected by semiquantitative reverse transcription-polymerase chain reaction and Western blot. Survivin and control small hairpin RNA (shRNA) expression constructed vectors were stably transfected into gastric cancer SGC7901 cells. The cells were in turn subjected to irradiation, cisplatin or fluorouracil (5-FU) treatment for colony formation, methyl-thiazolyl-tetrazolium cell viability and flow cytometry assays in vitro. An in vivo nude mouse xenograft assay was performed to assess the effects of Survivin knockdown on regulation of the sensitivity of SGC7901 cells to irradiation, cisplatin or 5-FU treatment.
  
  
  RESULTS
  Survivin shRNA markedly inhibited levels of survivin messenger RNA and protein in SGC7901 cells and significantly increased sensitivity of the tumor cells to radiation treatment, ie, the mean lethal and quasi-threshold doses in survivin shRNA-transfected cells were significantly lower than that of the negative control shRNA-transfected and parental cells. The same is true for cisplatin- and 5-FU-treated tumor cells, ie, colony formation and cell viability of the survivin-knocked down SGC7901 cells were reduced, while apoptosis was induced compared with the control cells. Furthermore, the xenograft assay showed survivin knockdown in SGC7901 cells suppressed tumor formation and growth compared with the controls.
  
  
  CONCLUSIONS
  Knockdown of survivin expression enhanced sensitivity of gastric cancer cells to radiation, cisplatin and 5-FU treatment in vitro and in nude mice. These results demonstrate that clinical trails are warranted of survivin shRNA as an adjuvant therapy for gastric cancer patients.
authors.affiliation: Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Shen
authors.forename: Jian-yong
authors.initials: JY
authors.lastname: Zheng
authors.forename: Hai
authors.initials: H
authors.lastname: Shi
authors.forename: Zhang
authors.initials: Z
authors.lastname: Zhang
authors.forename: Wei-zhong
authors.initials: WZ
authors.lastname: Wang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D002945:Cisplatin / Q000494:pharmacology; D005260:Female; D005472:Fluorouracil / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D020868:Gene Silencing / Q000187:drug effects*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism*; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000077022:Survivin; D014162:Transfection; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; C107489:BIRC5 protein, human; D051034:Inhibitor of Apoptosis Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000077022:Survivin; D002945:Cisplatin; D005472:Fluorouracil