title: siRNA targeting Livin decreases tumor in a xenograft model for colon cancer.
abstract: OBJECTIVE
  To evaluate the effect of silencing Livin gene expression with siRNA to apoptosis and proliferation in a colon cancer cell line.
  
  
  METHODS
  To investigate the anticancer effect of silencing Livin gene expression, we established an siRNA transfected cell line using the HCT116 colon cancer cell line. After confirming the successful transfection, MTT assay, flow cytometry and annexin V staining were employed to evaluate the antiapoptotic effect. To confirm the in vivo effect of Livin-siRNA, different doses of Livin-siRNA were injected into xenografted tumors in BALB/c nude mice model.
  
  
  RESULTS
  Livin expression was dramatically decreased after siRNA transfection, especially at 25 μmol/L of siRNA, but this suppression was not dose-dependent. The cell count at 18 h after transfection was significantly reduced as compared with controls (P < 0.01), but tended not to decrease proportionally depending on transfected dose or time. MTT assay revealed that silencing the Livin gene suppressed cellular proliferation at 18 h after transfection (P = 0.04); however, the inhibitory effect disappeared thereafter. Also, there was no significant difference in cellular proliferation depending on siRNA dose. The rate of apoptosis also increased with silencing of the Livin gene. In vivo, the tumor size significantly decreased after Livin-siRNA injection at 20 μmol/L concentration (P = 0.03). There were no significant body weight changes of mice after siRNA injection. Histologic examination revealed no significant toxic reaction in kidney, liver and brain of mice.
  
  
  CONCLUSIONS
  siRNA-mediated downregulation of Livin expression can induce apoptosis in colon cancer in vitro and in vivo, which suggests the possibility of new cancer therapeutics using siRNA.
authors.affiliation: Department of Surgery, Ewha Womans University School of Medicine, Seoul 158-710, South Korea.
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Oh
authors.forename: Ryung-Ah
authors.initials: RA
authors.lastname: Lee
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Kim
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D003110:Colonic Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology* / Q000627:therapeutic use; D014162:Transfection; D014183:Transplantation, Heterologous; D023041:Xenograft Model Antitumor Assays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C419866:BIRC7 protein, human; D051034:Inhibitor of Apoptosis Proteins; D009363:Neoplasm Proteins; D034741:RNA, Small Interfering