新型靶向拓扑异构酶I的抗肿瘤化合物库的设计、合成及生物活性研究

Today the search for novel TopoI-targeted scaffolds have drawn considerable research efforts in the hope of developing more effective antitumor drugs. As the only clinically available Topo I-targeted antitumor drugs, the CPTs suffer from many drawbacks such as chemically unstable, severe side effects, drug resistance and so on, which make the discovery of novel non-CPTs antitumor agents targeted to TopoI become a very active research field in recent years..Base on the structurally common feature of the TopoI-targeted compounds derivatived from Indenoisoquinolines, benzo[c]phenanthridines, Luotonins or Indolocarbazoles, and their basic mechanism of interaction with Topo I and DNA, we thought it would be a rational way to coin novel Topo I-targeted scaffolds by combination a flat planar motif with a hydrophilic moiety as side chain and the results in our recent studies really support the idea.These finding motivate us to put up with the research project to design and synthesize a 100 to 120 compounds library as potential anticancer-drug molecules targeted to the Topo I in the guides of the theories such as "privileged structure", "bio-isosterism alternation", "structure diversity", "fragment-based lead discovery" commonly used in drug-design, then to test the growth inhibitory effects of the synthesized compounds on selected tumor cell lines and to conduct a SAR/QSAR Study in the aim of identification several promising candidates for further research.

靶向Topo I的药物设计是目前重点研发的抗肿瘤药物之一。喜树碱类抗肿瘤药物由于其化学性质不稳定，毒性大，易产生耐药等缺陷，使得寻找靶向Topo I的非喜树碱类抗肿瘤新药，成为了近年来抗肿瘤药物研究的重要领域。.本研究课题是基于我们对以茚烯酮并异喹啉酮、苯并啡啶、骆驼宁碱及吲哚并咔唑为基本骨架的Topo I抑制剂在结构上的共性进行了研究和概括，结合对它们作用机制的初步认识，提出了平面结构单元与亲水侧链单元组合的化合物设计思路，并通过前期的实验研究验证了这一设计方法的可行性。本课题拟在这一设计思路及前期研究的工作基础上，综合采用优势结构理论、电子等排体替换、分子多样性及基于片段的先导化合物发现等药物分子设计理论，拟合成出含100-120个结构新颖的靶向Topo I的抗肿瘤化合物的化合物库，对其抗肿瘤活性、拓扑异构酶的抑制活性等进行构效关系研究，从中筛选出活性好的化合物进行进一步深入研究。

我们设计、合成和表征了两大类56个化合物，包括45个2, 3-二取代喹唑酮类化合物(五个系列)和11个N-杂苯并菲啶类衍生物, 研究了这些化合物的抗癌活性, 并对前者的抗癌作用机制进行了研究.. 一、(取代)邻氨基酸和乙酐加热回流, 所得产物分别与丁胺, N,N-二甲氨基丙胺, N,N-二甲氨基乙胺等反应, 再和芳香醛缩合得到5个系列45个2-芳乙烯基-4-喹唑酮, 其结构经NMR, MS, IR和单晶X射线衍射确认..用MTT法测试了45个化合物对MGC-803 (胃癌细胞)、NCI-H460 (肺癌细胞)、HepG2 (肝癌细胞)、A549 (肺癌细胞)、A375 (人皮肤黑色素瘤细胞)的体外抗肿瘤活性, 发现其中16个化合物对这五种癌细胞都具有较高的抗癌活性(IC50: 3.05~18.71 μmol/L). 利用流式细胞技术研究了4a和14c对MGC-803细胞周期的影响, 结果表明化合物4a和14c将MGC-803阻滞在G2和S期..研究表明14c是p53磷酸化和乙酰化双靶向的抑制剂. 它通过抑制p53 (s392)位点的磷酸化和p53 (k373)位点的乙酰化来封闭p53的功能. 14c封闭p53功能后通过p21放开对cdk2激酶的管制, 进而促使凋亡信号逐级传递; 凋亡信号传递到线粒体后, 细胞通过快速上调促凋亡蛋白Bim, 同时下调抗凋亡蛋白Bcl-2的表达启动凋亡过程. 本研究为以封闭p53功能为新型靶点的抗肿瘤药物设计提供了重要参考..二、取代芳乙酸酯依次与DMFDMA及芳胺反应, 所得产物加热关环得到3-芳基-4-羟基喹啉; 它与三氯氧磷反应得3-芳基-4-氯喹啉, 再依次与伯胺、氯甲酸乙酯反应，所得产物加热关环即可得到N-杂苯并菲啶类化合物, 其结构经NMR和HRMS进行了表征确认..对MGC-803 (人胃癌细胞)、NCI-H460 (人肺癌细胞)、HepG-2 (人肝癌细胞)以及7404 (人肝癌细胞)的体外抗肿瘤活性结果表明, 所合成的目标化合物对这四种癌细胞均具有很好的抑制活性. 其中, 24f对肿瘤细胞系NCI-H460, 7404和 HepG2抑制活性最好, IC50 值分别为 0.477, 0.577 和 0.022 µmol/L; 而24g对肿瘤细胞系MGC-803的抑制活性最好, IC50 值为1.547 µmol/L.