青蒿琥酯对子宫颈癌裸鼠移植瘤放射增敏作用的研究

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

目的探讨青蒿琥酯对子宫颈癌HeLa细胞裸鼠移植瘤的放射增敏效应及其作用机制。方法建立子宫颈癌HeLa细胞裸鼠移植瘤模型。待移植瘤平均体积增至5mm×5mm×5mm时，采用随机数字表法将裸鼠分为对照组、单纯药物组（青蒿琥酯）、单纯照射组（10Gy）及药物＋照射组（青蒿琥酯＋10Gy）。测量移植瘤体积，计算肿瘤体积抑制率，并对移植瘤标本进行HE染色，流式细胞仪检测移植瘤细胞周期及Western blot检测移植瘤组织中CyclinBI、Cdc2、Weel蛋白的表达。结果药物＋照射组裸鼠移植瘤体积为（448．9±99．7）mm^3，显著低于单纯药物组（1444．2±794．8）mm。和单纯照射组（954．5±53．2）mm^3（t=7．89、3．02，P〈0．05），其抑制率达72．34％。HE染色病理切片观察到单纯照射组和药物＋照射组移植瘤细胞有明显凋亡，其中，以药物＋照射组凋亡最显著。流式细胞仪检测细胞周期发现，单纯药物组与对照组相比，移植瘤细胞的G0／G1期、S期、G2／M期细胞比例均无明显变化。药物＋照射组移植瘤细胞的G2／M期细胞比例为（14．9±2．5）％，较单纯照射组（28．2±1．4）％降低（t=4．41，P〈0．05），G0／G1期细胞比例（50．9±3．5）％较单纯照射组（41．3±3．8）％上升（t=4．12，P〈0．05）。Western blot检测发现，药物＋照射组移植瘤组织中CyelinB1蛋白表达水平较单纯照射组明显升高，Weel蛋白表达水平较单纯照射组明显降低，而Cdc2蛋白在各处理组中的表达与对照组差异无统计学意义。结论青蒿琥酯对子宫颈癌HeLa细胞裸鼠移植瘤具有放射增敏作用，可能与其调节G2期调控关键因子CyelinB1、Weel蛋白的表达从而抑制肿瘤细胞G2／M期阻滞有关。

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 Weel 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 Weel 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 Weel.