Inhibitory Effect of Silencing STAT3 Gene by shRNA on Growth of Xenografted Human Esophageal Carcinoma Cell Line EC1 in Nude Mice

Objective Short hairpin RNA（shRNA）plasmid was constructed to investigate its effects on human esophageal carcinoma cell line EC1 in nude mice,and to investigate the feasibility and specificity of gene therapy for esophageal carcinoma. Methods The plasmid pSUPER containing the sequence of shRNA targeting STAT3 was constructed.The EC1 cells transfected with stable pSUPER plasmid were regarded as experimental group and the EC1 cells without being treated by pSUPER plasmid as the control group.The xenografted tumor model was established.Tumor growth was observed,histopathological changes was tested by HE and the mRNA and protein expression of STAT3 were measured by RT-PCR and immunohistochemical staining. Results The tumor growth was obviousibly suppressed;histopathology in the control group showed that the tumor volumes were bigger and high atypic of tumor cells were seen.Futhermore,RT-PCR and immunohistochemical results indicted that STAT3 mRNA and protein expression was reduced in excised tumors. Conclusion Silencing STAT3 gene by shRNA effectively inhibits the tumorigenesis of subcutaneously xenografted EC1 cells in nude mice and down-regulated the STAT3 mRNA and protein expression in vivo;it may be a potential therapeutic method to treated human cancer and a possible new approach for esophageal carcinoma gene therapy.