Effect of RNA interference of STAT1 expression on radiosensitivity and cell cycle of esophageal carcinoma cell line Eca109

Objective To inhibit the gene expression of signal transducer and activator of transcription factor 1 (STAT1) in human esophageal squamous cell carcinoma cell line Eca109 by RNA interference and investigate its effect on the radiosensitivity and cell cycle of Eca109 cells.Methods Interference vector pSTAT1-shRNA for STAT1 gene was designed and constructed.After being mixed with lentiviral packaging plasmids,the interference vectors were used to transfected 293T cells.Virus solution was collected to infect ECA109 cells.Real-time PCR and Western blot were used to measure the mRNA and protein expression levels of STAT1 in Eca109 cells.Colony formation assay and flow cytometry were used to evaluate the radiosensitivity and cell cycle distribution of Eca109 cells.Results All Eca109 cells were divided into blank control group,transfection-positive group,and transfection-negative group.The transfection-positive group showed significantly lower mRNA and protein expression levels of STAT1 than the other two groups.The values of D0,SF2,and Dq of transfection-positive group were 2.03 Gy,0.83,and 1.20 Gy,respectively,lower than those of blank control group (2.98 Gy,0.88,and 1.39 Gy) and those of transfection-negative cells (3.02 Gy,0.88,and 1.57 Gy).At 12 h,24 h,and 48 h after 4 Gy-irradiation,the transfection-positive group showed significantly higher percentage of G0 + G1 than the blank control group and transfection-negative group (34.13％ vs 22.03％ vs 22.27％,F =7.56,P =0.023 ; 43.80％ vs 28.40％ vs28.63％,F=10.01,P=0.012;53.20％ vs42.2％ vs41.83％,F＝10.73,P=0.010) and significantly lower percentage of G2 + M than the blank control group and transfection-negative group (14.33％ vs 32.23％ vs 32.23％,F=16.86,P=0.003;27.73％ vs 43.53％ vs 44.00％,F=26.62,P=0.001;14.23％ vs27.97％ vs27.93％,F=40.34,P=0.000).Conclusions RNAinterference of STAT1 in Eca109 cells does not affect the proliferation ability of Eca109 cells,and it can increase the radiosensitivity of Eca109 cells probably by regulating cell cycle after irradiation. Key words: Ribonucleic acid interference ;  Signal transducer and activator of transcription ; Radiosensitivity ;  Cell cycle;  Cell line, esophageal neoplasms