Effect of uncoupling protein 2 gene on radiation sensitivity of Siha cells

Abstract

Objective To investigate whether silencing UCP2 can sensitize cervical cancer cell line Siha to radiation. Methods Siha cells were transfected with UCP2 siRNA and then irradiated by X-ray. The radiosensitivity of Siha cells was verified by colony formation, CCK-8, apoptosis and immunofluorescence assays. The mitochondrial membrane potential and the production of reactive oxygen species (ROS) were detected to further explore the related mechanism. Results RT-PCR and Western blot assays showed that the expression of UCP2 in Siha cells was increased after irradiation and the UCP2 siRNA successfully silenced the expression of UCP in cells. According to the survival curves, the D0, Dq, N and SF2 were 1.54, 1.31, 2.31 Gy and 0.52 for siUCP2 group, 2.50, 3.64, 4.30 Gy and 0.83 for blank control group, and 3.34, 2.16, 1.91 Gy and 0.69, for siNC group, respectively. The radiosensitivity enhancement ratio of silent group was 0.62 and 0.46, compared with blank control group and negative control group, respectively. The proliferative activity of cells in the silent group was lower than that in the control group (t=13.2, P<0.05). Apoptosis levels in the silent group were significantly higher than those in the control group after irradiation(t=3.14, P<0.05). At 4 h after irradiation, the ROS production in the silent group was significantly higher than that in the control group (t=19.10, P<0.05). At 24 h after irradiation, the mitochondrial membrane potential of Siha cells in the silent group was significantly lower than that in the control group (t=4.18, P<0.05). Conclusions The radiosensitivity of Siha cells is enhanced after UCP2 silencing, and thus UCP2 may applicable as a new target for radiosensitization of cervical cancer cells. Key words: Cervical cancer; RNA interference; Uncoupling protein 2; Apoptosis; Radiation sensitivity