Silencing of mutant p53 by siRNA induces cell cycle arrest and apoptosis in human bladder cancer cells.
BACKGROUND
p53 is the most frequently mutated tumor-suppressor gene in human cancers. It has been reported that mutations in p53 result not only in the loss of its ability as a tumor suppressor, but also in the gain of novel cancer-related functions that contribute to oncogenesis. The present study evaluated the potential of silencing of mutant p53 by small interfering RNA in the treatment of bladder cancer cells in vitro.


METHODS
We used the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay to assess cell viability and flow cytometry to detect cell cycle alterations and apoptosis. The related molecular mechanisms were assessed by western blotting. We also used the MTT assay and flow cytometry to investigate if silencing of mutant p53 by knockdown with small interfering (si)RNA would change the sensitivity to cisplatin treatment.


RESULTS
Using 5637 and T24 human bladder cancer cell lines characterized by mutations in p53, we found that silencing of the mutant p53 by RNA interference induced evident inhibition of cell proliferation and viability, which was related to the induction of G2 phase cell cycle arrest and apoptosis. Moreover, our study also showed that the p53-targeting siRNA cooperated with cisplatin in the inhibition of bladder cancer cells.


CONCLUSIONS
These findings suggest that RNA interference targeting mutant p53 may be a promising therapeutic strategy for the treatment of bladder cancer.
Department of Urology, The First Affiliated Hospital, School of Medicine, Zhejiang University, Qingchun Road 79, Hangzhou, Zhejiang Province, 310003, China.
Hai-Bin
HB
Zhu
Kai
K
Yang
Yan-Qi
YQ
Xie
Yi-Wei
YW
Lin
Qi-Qi
QQ
Mao
Li-Ping
LP
Xie
D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D059447:Cell Cycle Checkpoints / Q000235:genetics*; D049109:Cell Proliferation; D005434:Flow Cytometry; D020868:Gene Silencing; D006801:Humans; D009154:Mutation / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
D012333:RNA, Messenger; D034741:RNA, Small Interfering; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53