Effect of FAM83D silencing on radiosensitivity of esophageal squamous cell carcinoma cells by mediating epithelial-mesenchymaltransition / 中华放射肿瘤学杂志

ABSTRACT

Objective:To examine the effect of FAM83D knockdown on proliferation, survival ability and invasion of human esophageal squamous cell carcinoma after X-ray radiation, and explore the mechanism.Methods:The expression of FAM83D, E-cadherin and vimentin in tumor tissues was detected in 69 cases of esophageal squamous cell cancer by using immunohistochemical method. The siRNA based on the sequences of the FAM83D mRNA were synthesized to transfect into the cultured ECA109 cells as FAM83D shRNA group. The effect of silencing FAM83D gene was evaluated to determine the protein levels of FAM83D in the human oesophageal squamous cell carcinoma ECA109 and KYSE30 cells using western blotting. MTS, clone formation, and Transwell assay were employed to examine the proliferation, survival ability and invasion of ECA109 and KYSE30 cells in vitro, respectively. We used flow cytometry assay to analyze distribution of cell apoptosis in different groups. Western blotting was used to examine the expression of cell metastasis-related molecules and apoptosis-related protein. Results:The strong expression rates of FAM83D, E-cadherin, and vimentin were 55%(38/69), 36%(25/69) and 61%(42/69) in the tumor tissues, respectively. FAM83D protein expression was significantly and negatively correlated with the expression of E-cadherin ( r=-0.350, P<0.01), and positively with the expression of vimentin ( r=0.470, P<0.01). Western blotting results demonstrated that silencing FAM83D gene significantly reduced the FAM83D protein expression ( P<0.01). MTS data demonstrated that FAM83D knockdown after irradiation significantly inhibited the proliferation of esophageal squamous cell carcinoma ECA109 and KYSE30 cells ( P<0.05). The data from the clone formation assay revealed that the radiosensitivity was increased after downragulation of FAM83D expression ( P<0.01). In addition, the invasive abilities of oesophageal carcinoma cells transfected with FAM83D shRNA after irradiation were significantly inhibited compared with those of the NC group ( P<0.01), followed by the downregulation of N-cadherin, vimentin, Snail, p-Akt and p-GSK-3β expression, and the upregulation of E-cadherin expression ( P<0.01). The apoptosis rate of tumor cells in FAM83D shRNA group after irradiation was markedly increased ( P<0.01), followed by a decrease of Bcl-2 and Mcl-1 expression and an increase of Cleaved caspase-3 expression ( P<0.01). Conclusions:FAM83D expressions was found to be closely related to the invasion and development of ESCC. Furthermore, siRNA interference technology inhibited the expression of FAM83D gene in oesophageal squamous cell carcinoma cells, reduced the proliferation, invasion of cells, induced cell apoptosis, and increased radiosensitivity, which may be associated with regulating the epithelial-mesenchymaltransition via Snail/Akt/GSK-3β signaling pathways.