摘要
目的 :研究 4′ ,5′ ,7 三羟基异黄酮 (genistein)对NB4白血病细胞生长和分化的影响 ,揭示其诱导细胞凋亡作用。方法 :分别用NBT还原力分析、DNA电泳分析观察药物诱导分化和凋亡作用 ;Northern杂交分析和质粒DNA断裂分析检测bcl 2基因表达和DNA拓扑异构酶II活性。结果 :Genistein可明显抑制NB4细胞生长 ,并致细胞大量死亡。在浓度高于 40 μmol·L-1时 ,可诱导典型的凋亡形态 ,同时 ,细胞bcl 2基因表达受到抑制。Genistein可促进DNA拓扑异构酶II介导的DNA断裂 ,但诱导NB4细胞分化作用较弱。结论 :Genistein通过诱导细胞凋亡来杀伤和抑制NB4细胞的生长 。
AIM: To investigate the possible actions of isoflavone genistein in inducing apoptosis and differentiation of NB4 leukemia cells. METHODS: NBT dye reduction ability was used as the biomarker of differentiation of NB4 cells. Apoptosis was assayed through genomic DNA gel electrophoresis. Expression of bcl 2 gene and DNA topoisomerase II activity were examined with Northern blot analysis and plasmid DNA breakage analysis, respectively. RESULTS: Genistein (40 μmol·L -1 ) significantly suppressed the growth of NB4 cells, while a large amount of cells died with the prolongation of the drug exposure time. At concentration larger than 40 μmol·L -1 , genistein induced condensation of chromatin, breakage of nucleus, and appearance of DNA ladder after agarose electrophoresis in NB4 cells. In consistent with the induction of apoptosis, genistein inhibited expression of bcl 2 gene. At 10～200 μmol·L -1 , genistein stimulated the topoisomerase II mediated DNA breakage. On the other hand, genistein induced increase of NBT positive cell number, but the positive rates were lower than 50%. CONCLUSION: Genistein inhibited the growth of NB4 cells through induction of apoptosis and cell death. The mechanism of action might be associated with suppression of DNA topoisomerase II activity. Induction of differentiation may contribute little to the therapeutic activities of genistein in leukemia cells.
出处
《药学学报》
CSCD
北大核心
2000年第4期253-256,共4页
Acta Pharmaceutica Sinica
