Effects of plasmid-based Stat3-specific short hairpin RNA and GRIM-19 on PC-3M tumor cell growth.
OBJECTIVE
Persistent activation of signal transducers and activators of transcription 3 (Stat3) and its overexpression contribute to the progression and metastasis of several different tumor types. For this reason, Stat3 is a reasonable target for RNA interference-mediated growth inhibition. Blockade of Stat3 using specific short hairpin RNAs (shRNA) can significantly reduce prostate tumor growth in mice. However, RNA interference does not fully ablate target gene expression in vivo, owing to the idiosyncrasies associated with shRNAs and their targets. To enhance the therapeutic efficacy of Stat3-specific shRNA, we applied a combination treatment involving gene associated with retinoid-IFN-induced mortality 19 (GRIM-19), another inhibitor of STAT3, along with shRNA.


METHODS
The coding sequences for GRIM-19, a cellular STAT3-specific inhibitor, and Stat3-specific shRNAs were used to create a dual expression plasmid vector and used for prostate cancer therapy in vitro and in mouse xenograft models in vivo.


RESULTS
The coexpressed Stat3-specific shRNA and GRIM-19 synergistically and more effectively suppressed prostate tumor growth and metastases when compared with treatment with either single agent alone.


CONCLUSIONS
The simultaneous use of two specific, but mechanistically different, inhibitors of STAT3 activity exerts enhanced antitumor effects.
Zhang
Ling
L
Prostate Diseases Prevention and Treatment Research Center and Department of Pathophysiology, School of Basic Medicine, Jilin University, Changchun, PR China.
Gao
Lifang
L
Li
Yang
Y
Lin
Guimiao
G
Shao
Yueting
Y
Ji
Kun
K
Yu
Hao
H
Hu
Jiadi
J
Kalvakolanu
Dhananjaya V
DV
Kopecko
Dennis J
DJ
Zhao
Xuejian
X
Xu
De-Qi
DQ
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009247:NADH, NADPH Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D011467:Prostate / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D034741:RNA, Small Interfering / Q000378:metabolism*; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D023041:Xenograft Model Antitumor Assays
D051017:Apoptosis Regulatory Proteins; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; D009247:NADH, NADPH Oxidoreductases; C439057:NDUFA13 protein, human