Effects of X-ray irradiation combined with RNAi against STAT3 on proliferation and apoptosis of human esophageal carcinoma cells / 中国癌症杂志

ABSTRACT

Background and purpose:Several reports demonstrated that the expression of STAT3 has been found to be an oncogene in solid tumors such as head and neck squamous cell carcinoma,esophageal carcinoma and prostate carcinoma.This study was done to explore the effects of X-ray irradiation combined with RNAi against STAT3 on proliferation and apoptosis of human esophageal carcinoma cell line Eca-109.Methods:Three pairs of DNA template coding siRNA were synthesized against STAT3 to reconstruct pRNAT-U6.1-siRNA-STAT3,which was transfected into Eca-109 cells,the positive cell clones were screened with G418.Inhibitory effect of STAT3 mRNA and protein in Eca-109 cells was detected by RT-PCR and Western blot,respectively.The transfected cells were exposed to 0,2,4,6 and 8 Gy X-ray respectively;the survival fraction of Eca-109 cells was analyzed by clone formation assay,and flow cytometry was applied to analyze cell apoptosis at the dose of 4 Gy.Results:pRNAT-U6.1-siRNA-STAT3 was reconstructed and identifi ed as correct by sequencing.RT-PCR and Western blot analyses demonstrated that STAT3-siRNA could obviously reduce the expression of STAT3 mRNA and protein in Eca-109 cells.Clone formation assay and flow cytometry results showed that irradiation at different doses combined with STAT3-siRNA could inhibit the proliferation of Eca-109 cells,irradiation with 4 Gy X-ray could induce apoptosis.Conclusion:X-ray irradiation combined with RNAi against STAT3 could inhibit the proliferation of Eca-109 cells and induce apoptosis.