Objective:To investigate the effects of silence PTTG expression by small interference RNA(siRNA) on proliferation and radiotherapeutic sensitivity of endometrial carcinoma cells(HEC-1A). Methods:Vectors pSilencer3.0-H1-PTTG-SiRNA were constructed to transcribe functional siRNA specially targeting PTTG. The interfering plasmids were used to transfect HEC-1A cells with lipofectmine 2000 transfection reagent. PTTG protein expression levels were analyzed by Western blot method. The HEC-1A cells were treated with PTTG siRNA,radiotherapy and PTTG siRNA combined with radiotherapy,and cells without transfection were as control. MTT assay was used to detected cell proliferation,and the apoptosis of HEC-1A cells was evaluated by flow cytometry. Results:Recombinant siRNA expression vector targeting PTTG was constructed. The result of MTT showed that the growth of HEC-1A cells was influenced after PTTGsiRNA transfection,radiotherapy and PTTGsiRNA transfection combined with radiotherapy. Inhibitory rate of radiotherapy group,PTTGsiRNA group and PTTGsiRNA combined with radiotherapy group were(31.39 ± 5.62)%,(38.37 ± 4.48)%,(54.65 ± 6.27)%,respectively. The apoptosis rate at 48 h of control group,radiotherapy group,PTTGsiRNA group,PTTGsiRNA combined with radiotherapy group were (6.53 ± 0.80)%,(32.72 ± 4.56)%,(38.96 ± 4.37)%,(64.76 ± 6.53)%,respectively,by the flow cytometry analysis. There were significant differences between control group and PTTGsiRNA group or radiotherapy group,and there were significant differences between PTTGsiRNA combined with radiotherapeutic group and PTTGsiRNA group or radiotherapy group. Conclusion:The siRNA expression vector targeting PTTG was successfully constructed.PTTG RNA interference may inhibit the cell proliferation and induce apoptosis in endometrial carcinoma cells,which can upregulate radiotherapeutic sensitivity of HEC-1A cells.