重楼活性单体(PP-22)对人胃癌MGC803细胞增殖和凋亡的影响

Effects of a Monomer Purified from Paris Polyphylla( PP-22 ) on Proliferation and Apoptosis of Human Gastric Carcinoma MGC803 Cells

目的探讨重楼活性单体PP-22对人胃癌MGC803细胞增殖和凋亡的影响及联合氟尿嘧啶或洛铂的抗癌效应。方法采用噻唑蓝(MTT)法和克隆形成抑制实验观察不同浓度的重楼单体PP-22对人胃癌MGC803细胞增殖抑制作用;采用PP-22分别联合氟尿嘧啶或洛铂,观察对人胃癌MGC803细胞增殖抑制作用;碘化丙啶(PI)单染及Annexin V-FITC/PI双染流式细胞术检测细胞周期变化及细胞凋亡水平;Western blotting检测PP-22对细胞凋亡相关蛋白的表达。结果与正常肝L02细胞相比,重楼单体PP-22能显著抑制MGC803细胞的生长,作用呈剂量-效应关系;随着PP-22浓度的增加,细胞克隆形成逐渐减少,与细胞对照组相比有显著差异;PP-22与不同浓度的化疗药物(氟尿嘧啶,洛铂)联合作用于MGC803细胞48 h,可提高MGC803细胞对这些化疗药物的敏感性;不同浓度PP-22作用后,细胞阻滞于S期;存在Caspase-3和Caspase-9蛋白的活化和降解,抗凋亡蛋白Bcl-2减少,细胞促凋亡蛋白Bak的表达增加。结论 PP-22通过诱导人胃癌MGC803细胞凋亡抑制细胞增殖,并提高MGC803细胞对氟尿嘧啶,洛铂的敏感性。

OBJECTIVE To investigate the effects of a monomer purified from Paris Polyphylla（PP-22） on proliferation, apoptosis of human gastric carcinoma MGC803 ceils and to study the sensitizing effect of PP-22 on the proliferation of MGC803 cells to chemotherapeutic drugs 5-fluorouraeil（5-Fu） or lobaplatin. METHODS MTT assay and cell eolone formation inhibitory assay were used to determine the inhibitory effect of PP-22 on human gastric carcinoma MGC803 cells. The sensitizing effects of PP-22 on MGC803 cells to chemotherapeutic drugs 5-Fu, lobaplatin were determined by Mq＊F assay. The percentage of apoptotie cells and cell cycle distribution were determined by flow eytometry. The expression of cell apoptosis associated proteins were analyzed by Western blotting. RESULTS MTT assay showed that PP-22 inhibited gastric carcinoma MGC803 cells proliferation in dose-dependent manner （ r = 0. 90, P 〈 0. 05 ） , but did not inhibit the growth of normal liver L02 cells at the same concentration. Cell colony formation inhibitory assay demon- strated that cell clones decreased with the increase of drug concentrations. The chemosensitivity of 5-Fu, or lobaplatin combined with PP-22 was improved compared with PP-22 group, respectively. PI staining analysis showed that the cell cycle was arrested at S phase. Western blotting detecting showed that the expression of Caspase-9, Caspase-3 were downregulated, the anti-apoptotic protein Bcl-2 is downregulated and pro-apoptotic protein Bak upregulated. CONCLUSION PP-22 inhibits proliferation and induces apoptosis of MGC803 cells effectively and also sensitizes MGC803 cells to chemotherapeutic drugs.