ROLE OF TOPOISOMERASE II IN NBQ MEDIATED TUMOR CELL DIFFERENTIATION

3-硝基苯并噻唑并[3，2-a]喹啉（NBQ）嵌入DNA中， 显示出作为抗肿瘤剂的强大潜力。 我们实验室的研究 其作用方式显示NBQ的细胞毒性与 拓扑异构酶II介导的DNA链断裂。 此外，NBQ显着 增强成年蝾螈体内透镜再生 体外诱导HL-60和DFaDu细胞分化 肿瘤细胞系 NBQ，在刺激分化的非致死剂量下， 在体外将拓扑异构酶II与纯化的DNA结合。 拓扑异构酶II参与细胞毒性和分化 NBQ的活性，引发了拓扑异构酶的作用的问题 在NBQ诱导的分化过程中， 知识分子 NBQ诱导分化的机制，与其 细胞毒性作用，将进一步发展一种潜在的新癌症模式， 化疗 为了探讨这个问题，我们将研究NBQ的影响 和八个类似物使用分子和细胞方法的组合。 因为可切割复合物的DNA序列定位， NBQ和各种类似物，与拓扑异构酶II应相同， 药物效果的比较更易于解释。 我们提出 表征八种NBQ类似物的细胞毒活性， 评价拓扑异构酶活性的抑制作用。分化 将每种类似物的能力与NBQ（80 - 90%HL-60细胞）进行比较 分化成粒细胞系列）。 为了理解这个机制 NBQ和类似物的作用，我们将评估;蛋白质的形成 完整细胞中的连接链断裂，拓扑异构酶的抑制 体外活性和促进染色体异常。 的影响 NBQ类似物对细胞周期的影响将在 与细胞毒性浓度相比诱导分化。 图案 NBQ刺激的拓扑异构酶II介导的DNA切割将是 与NBQ类似物刺激的切割模式相比， 拓扑异构酶II使阿霉素、VP-16和m-AMSA中毒。 最后 将在耐药HL-60和m-AMSA中研究NBQ类似物的作用。 最后，将研究NBQ类似物在耐药HL-60中的作用 细胞系（HL-60/NBA），这使我们能够研究差异的基础 在活性方面，特别是在分化诱导方面。

3-nitrobenzothiazolo[3,2-a] quinolinium (NBQ) intercalates in DNA and shows a strong potential as antitumor agent. Studies in our laboratory on its mode of action revealed that the cytotoxicity of NBQ is associated with topoisomerase II- mediated DNA strand breaks. Moreover, NBQ significantly enhances in vivo lens regeneration in the adult newt Notophtalmus viridescens, and induces in vitro the differentiation of HL-60 and DFaDu tumor cell lines. NBQ, at non-lethal doses that stimulate differentiation, binds in vitro topoisomerase II to purified DNA. The involvement of topoisomerase II in the cytotoxic and differentiation activities of NBQ, brings into question what is the role of topoisomerase II in the NBQ-induced differentiation. Knowledge of the molecular mechanism(s) through which NBQ induces differentiation, in contrast to its cytotoxic effect, will further a potentially new mode of cancer chemotherapy. To explore this question, we will study the effects of NBQ and eight analogs using a combination of molecular and cellular approaches. Because the DNA sequence localization of the cleavable complex, formed by NBQ and the various analogs, with topoisomerase II should be identical, the comparison of drug effects is more amenable to interpretation. We propose to characterize the cytotoxic activity of the eight NBQ analogues and evaluate athe inhibition f topoisomerase activity. The differentiation ability of each analog will compared to NBQ (80 - 90% HL-60 cells differentiated into the granulocytic series). To understand the mechanism of action of NBQ and analogs, we will evaluate; the formation of protein linked strand breaks in intact cells, the inhibition of topoisomerase activity i vitro, and promotion of chromosomal abnormalities. The effects of NBQ analogs on the cell cycle will be detected at concentration that induce differentiation compared with cytotoxic concentrations. The pattern of topoisomerase II-mediated DNA cleavage stimulated by NBQ will be compared to the cleavage pattern stimulated by NBQ analogs and the topoisomerase II poisons doxorubicin, VP-16 and m-AMSA. Finally, the effects of NBQ analogs will be studied in the resistant HL-60 and m-AMSA. Finally, the effects of NBQ analogs will be studied in the resistant HL-60 cell line (HL-60/NBA), which allows us to study the basis for differences in activity, specially, the induction of differentiation.