Radiosensitization effect of selenocystine on HeLa cells in vitro

Abstract

Abstract Objectives To study the effect of selenocystine (Selenocystine, SeC) on the radiosensitivity of human cervical cancer Hela cells, and to provide a new target for radiosensitivity of cervical cancer. Methods SeC were added to the cervical cancer Hela cells, and then irradiate with 200 cGy/min X‐rays. The radiosensitization effect of SeC on cervical cancer Hela cells were confirmed with the experiments of cell growth inhibition, clone formation, flow cytometry and Western blotting to detect apoptosis. Results SeC were added to the Hela cells at different doses of 0, 5, 10, and 20 μmol/L and incubating for 24 hours, the cell growth inhibition rates were: 0%, 22.68%, 41.71%, 74.19%, and the calculated IC50 was 14.83 μmol/L. The growth inhibition rate of Hela cells was dose‐dependent with the concentration of SeC. The results of the colony formation experiments showed that the cell colony formation rates of the single X‐ray irradiation doses of 0, 2, 4, 6, and 8 Gy were 100%, 77.56%, 46.89%, 28.67%, and 10.89%, respectively. After adding 5μmol/L SeC under the same irradiation dose, the colony formation rate was reduced to 70.98%, 59.45%, 30.67%, 14.29%, 3.72%; 5μmol/L SeC combined with radiation therapy can shift the survival curve to the left, and the D0 and Dq values were significantly smaller than those in the radiation group, P < 0.05. Hela cell apoptosis were detected by the flow cytometry showed that when the single X‐ray irradiation dose was 0, 2, 4, 8 Gy, the apoptosis scores were: 2.51 ± 0.06, 6.76 ± 0.03, 14.51 ± 0.15, 21.41 ± 0.08; When 5 μmol/L SeC was added and then combined with X‐ray irradiation, and the irradiation dose was 0, 2, 4, 8Gy, the apoptosis score of each group was: 10.89 ± 0.36, 15.18 ± 0.21, 31.19 ± 0.08, 45.53 ± 0.28, SeC combined with X‐ray had an interaction effect on Hela cells, and the apoptosis rate increased (F = 21.52, P < 0.01). When Hela cells were treated with SeC and X‐rays, the expression of PARP protein and phosphorylated p53 protein was significantly increased compared with the control group. Conclusions SeC may have a radiosensitizing effect on Hela cells, and its mechanism may be related to promoting apoptosis. SeC will be expected to become a new sensitization target for cervical cancer radiotherapy.

Keywords

• apoptosis
• cervical cancer
• HeLa cell
• radiosensitization
• selenocystine