title: MicroRNA-221 silencing predisposed human bladder cancer cells to undergo apoptosis induced by TRAIL.
abstract: OBJECTIVE
  Bladder cancer is the most common type of urologic cancer in Chinese males. The 5-year survival rate of advanced bladder cancer is approximately 20%-40%. There is an obvious urgent need for novel and effective therapies against bladder cancer. MicroRNAs (miRNAs) are a recently discovered class of noncoding RNAs; suppressing miRNA-221 might prove beneficial in several cancers. To explore novel and effective therapies against bladder cancer, we explored the effects of miRNA-221 silencing on the survival of bladder cancer cells.
  
  
  METHODS
  Northern blot analysis was used to determine miRNA-221 expression levels in bladder cancer T24 cells, RT4 cells and human normal urothelial cells. miRNA-221 was silenced with antisense oligonucleotides in T24 cells and pro-apoptotic effect of necrosis factor related apoptosis-inducing ligand (TRAIL) on miRNA-221-silenced cells was assessed with flow cytometry. The p27(kip1) protein expression in miRNA-221-silenced cells exposed to TRAIL was detected by Western blotting. The role of miRNA-221 silencing on T24 cell cycle phase distribution was investigated through flow cytometric analysis.
  
  
  RESULTS
  Human miRNA-221 was significantly up-regulated in bladder cancer T24 cells and RT4 cells compared to human normal urothelial cells. T24 cell was TRAIL-resistant cell line. MiRNA-221 silencing predisposed T24 cells to undergo apoptosis induced by TRAIL and resulted in an up-modulation of cyclin-dependent kinase inhibitor p27Kip1. MiRNA-221 suppression promoted the activation of caspase 3 induced by TRAIL in T24 cells.
  
  
  CONCLUSIONS
  MiRNA-221 silencing rendered human bladder cancer T24 cells to undergo apoptosis induced by TRAIL. Our findings suggest a potential role of suppressing miRNA-221 in human bladder cancer therapy.
authors.affiliation: Department of Urology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lu
authors.forename: Chao
authors.initials: C
authors.lastname: Lu
authors.forename: Guo-Ping
authors.initials: GP
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Hang
authors.initials: H
authors.lastname: Xiao
authors.forename: Xin-Ru
authors.initials: XR
authors.lastname: Wang
mesh_terms: D017209:Apoptosis / Q000502:physiology; D015152:Blotting, Northern; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002469:Cell Separation; D005434:Flow Cytometry; D020868:Gene Silencing; D006801:Humans; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology
chemical_list: D035683:MicroRNAs; D053221:TNF-Related Apoptosis-Inducing Ligand; C525709:MIR221, human