Abstract:

Abstract:Objective To observe the therapeutic effect of attenuated salmonella carrying siRNA-STAT3 plasmid on transplanted prostatic cancer in mice,and clarify the mechanism of siRNA-STAT3 of inducing apoptosis of prostatic cancer cells in mice. Methods The transplanted prostatic cancer  models of mice were built,then  the mice were randomly divided into Mock group, pGC-Si-Scramble group and pGC-Si-STAT3 group. The general status of the mice was observed and the changes of tumor volume were recorded.The expression levels of mRNA and protein of STAT3 and its downstream genes such as Bcl-2,c-Myc, HIF-1,cyclinD1 were analyzed with RT-PCR and THE Western blotting, and the apoptosis of tumor cells was detected with flow cytometry. Results The transplanted prostatic cancer models of the mice were built successfully.Compared with Mock group, the growth of tumor was suppressed obviously and the weights of tumors were lessened in pGC-Si-STAT3 group（P<0.05）.The result of flow cytometry revealed that the  early apoptotic rates in pGC-Si-STAT3 group, pGC-Si-Scramble group and Mock group were （29.1±1.6）%,（14.7±1.4）%,and（8.9±1.8）%, respectively. Compared with Mock group, the mRNA and protein expression levels of STAT3 in pGC-Si-STAT3 group were singnificantly decreased, the mRNA expressions of the downtream genes, such as BcL-2,c-Myc were decreased, and the protein expression levels of HIF-1, cyclinD1 were also decreaaed（P<0.05）.Conclusion The attenuated salmonella carrying SiRNA-STAT3 can inhibit the growth of transplanted prostatic cancer in mice by regulating the expressions of STAT3 downtream genes and inducing the apoptosis of tumor cells.

Key words: prostatic neoplasms, attenuated salmonella, STAT3; , RNA interfere