Radiosensitizing effect of artesunate on nude mice transplanted with HeLa cells of cervical cancer

Objective: To investigate the radiosensitization of artesunate on nude mouse transplanted with HeLa cells,and to explore its possible mechanisms. Methods: HeLa cells were inoculated into the nude mice to establish tumor model. Mice were randomly divided into 4 groups as blank control,artesunate group, radiation group and artesunate + radiation group when average volume of tumor were about 5 mm × 5 mm× 5 mm. During the term of treatment, the volume of tumors were measured every 2 days. After 14 days treatment, the mice were killed and tumor tissues were harvested for flow cytometry to detect the alteration of cell cycle. Meanwhile, the pathological change of the tumor tissue was observed with HE staining method, and the change of expression of cycle regulatory protein Cyclin B1, Cdc2 and Wee1 were detected by Western blot. Results: The growth of tumor was significantly inhibited by artesunate combined with radiation and its inhibition rate was 72.34%. Flow cytometry results showed that the percent of cells in G₁ phase increased and G₂ phase decreased in the artesunate + radiation group compared with those in irradiation group (t=4.41, 4.12, P<0.05). The expression level of Cyclin B1 was obviously increased while that of Wee1 decreased in the artesunate + radiation compared with irradiation group. There was no difference in the expression of Cdc2 among the four groups. Conclusions: Artesunate can dramatically increase the radiosensitivity of transplanted tumor of HeLa cells. The possible mechanism might be related to the decreasing G₂ phase by regulating the expression of Cyclin B1 and Wee1. (authors)