半边旗抗肿瘤有效成分对HL—60细胞DNA拓扑异构酶活性及其细胞 …

目的；研究半边旗有效成分５Ｆ，６Ｆ，Ａ对ＨＬ－６０细胞ＤＮＡ拓扑异构酶活性和细胞周期的影响。方法：应用ｐＢＲ３２２质粒ＤＮＡ作为底物测定酶的活性；细胞周期用流式细胞仪测定；应用噻唑蓝法测定药物对细胞生长的抑制率。结果：５Ｆ，６Ｆ，Ａ均能够抑制ＤＮＡ拓扑异构酶Ⅰ，Ⅱ的活性。

Effects of antitumor compounds isolated from Pteris semipinnata L on DNA topoisomerases and cell cycle of HL-60 cells.

AIM: To study the effect of the antitumor compounds 5F, 6F, and A from Pteris semipinnata L on the activities of DNA topoisomerases and cell cycle of HL-60 cells, and the synergism of compound 6F in combination with genistein in vitro. METHODS: DNA topoisomerases were isolated from HL-60 cell lines, and supercoiled pBR322 DNA was used as substrate to determine the activities of DNA topoisomerase I and II. Cell cycle was analyzed by flow cytometry (FCM). Cytotoxicity assay was tested by MTT method. RESULTS: Compounds 5F, 6F, and A inhibited the activities of DNA topoisomerase I and II. After exposure of the cells to compound 6F, an increase in cells in the S and G2/M phases and a decrease in cells in the G0/G1 phase of the cell cycle were observed. At low concentrations (57.8 and 115.6 nmol.L-1), compound 6F enhanced the cytotoxicity against HL-60 cell line in combination with genistein, q values were > 1.15. The enhancement times of 57.8 and 115.6 nmol.L-1 of 6F by genistein were 2.60 and 4.65, respectively. CONCLUSION: Compounds 5F, 6F, and A inhibited the activities of DNA topoisomerases of HL-60 cells. Compound 6F increased the number of cells in S and G2/M phases, decreased the population of G0/G1 phase cells, and enhanced the cytotoxicity of genistein, which had synergism with 6F in antitumor action.