MicroRNA-221 silencing predisposed human bladder cancer cells to undergo apoptosis induced by TRAIL.
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.
Lu
Qiang
Q
Department of Urology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Lu
Chao
C
Zhou
Guo-Ping
GP
Zhang
Wei
W
Xiao
Hang
H
Wang
Xin-Ru
XR
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
D035683:MicroRNAs; D053221:TNF-Related Apoptosis-Inducing Ligand; C525709:MIR221, human