Abstract: AIM:To investigate the effect of X-ray radiation on the expression of HOTAIR and epithelial-mesenchymal transition (EMT) related factors in esophageal squamous cell carcinoma (ESCC).METHODS:Eca109 cells were irradiated with 0,2,4,6,or 8 Gy of X-rays.After 0,2,4,8,16,or 24 h of radiation,the expression of HOTAIR,Snail and E-cadherin was detected by qRTPCR and Western blot.RESULTS:In Eca109 cells irradiated for 24 h,X-ray dose-dependently increased HOTAIR and Snail expression levels but decreased E-cadherin mRNA and protein expression.The mRNA expression levels of HOTAIR and Snail in the 6 Gy and 8 Gy groups were significantly higher than those in the 0 Gy group.Of note,Snail protein level dramatically increased in the 4 Gy group.The expression of E-cadherin mRNA and protein was statistically lower in the 6 Gy and 8 Gy groups compared with the 0 Gy group (P < 0.01).In Eca109 cells irradiated with 8 Gy X-ray,X-ray time-dependently increased the expression of HOTAIR and Snail but decreased E-cadherin mRNA and protein expression.HOTAIR and Snail mRNA and protein expression was significantly higher in the 8 and 16 h groups than in the 0 h group,while the expression of E-cadherin mRNA and protein was gradually decreased in the 8 h group compared with the 0 h group.CONCLUSION:X-ray induces abnormal expression of HOTAIR,Snail and E-cadherin time-and dose-dependently,which may result in the occurrence of cellular radioresistance.