ABSTRACT
Objective To study the effect of PinXl on radiosensitivity and ROS level of esophageal cancer cells.Methods Esophageal cancer cells were divided into control group (no cell transfection),radiation group (8 Gy of X-rays),PinX1 group (pDsRed1-PinX1 transfect to overexpression,radiation+PinX1 group (8 Gy X-rays after pDsRed1-PinX1 transfection).Cell proliferation was measured by MTT assay,cell apoptosis was measured by flow cytometry,the activation levels of Caspase-3 and Caspase-9 in cells were measured by Western blot,the cellular ROS level was determined using DCFH-DA probe,and the cell radiosensitivity was evaluated by the colony formation assay.The subcutaneous xenograft tumor model of EC9706 cells was established with nude mice,and each group received local irradiation every 4 days 8 Gy five fractions γ-rays.The nude mice bearing PinX1-transfected cells were implanted with PinX1 plasmid into tumor before radiotherapy to investigate the relationship between PinX1 overexpression and radiosensitivity in xenotransplantation mice models.Results Compared with control group cells,the survival rate of EC9706 cells of radiation group or PinX1 group decreased significantly from 100％ to (67.92±4.71) ％ and (83.14 ±4.01) ％ (t =9.433,4.957,P＜0.05),the apoptosis rate increased significantly from (6.47± 1.46) ％ to (44.38±4.16) ％ and (25.42 ±2.78) ％ (t =12.882,6.439,P ＜ 0.05),Caspase-3 activation level increased (t =6.655,2.531,P ＜0.05),and the activation level of Caspase-9 and cellular ROS was also significantly increased.Compared with radiation group cells,the cell viability of radiation+PinX1 group decreased from (67.92 ±4.71) ％ to (52.73 ±5.58) ％ (t =8.942,P＜0.05),the apoptosis rate increased from (44.38±4.16) ％ to (55.29±4.98)％ (t=3.707,P＜0.05),the activation levels of Caspase-3,-9,and the level of ROS in cells was increased (t =15.435,17.990,4.526,P＜0.05).The radiosensitivity of EC9706 cells was increased after PinX1 transfection with a sensitization ratio of 1.408.The volume of xenograft tumor with PinX1 overexpression cells in nude mice was significantly smaller than control.Conclusions Overexpression of PinX1 could inhibit the proliferation,induce apoptosis and increase the radiosensitivity of esophageal cancer cells.