稳定氮氧自由基标记的极光激酶A抑制剂的合成及生物活性研究

Aurora kinases are a family of mitotic serine/threonine kinases, which have been implicated in several vital events in mitosis. Deregulation of Aurora kinase activity can result in mitotic abnormality and genetic instability, leading to defects in centrosome function, spindle assembly, chromosome alignment, and cytokinesis. So they have received significant attention as new targets for anticancer therapy. Recently, it was reported that 2,4-bisanilinopyrimidine were Aurora A inhibitors with excellent selectively for Aurora A over Aurora B. However, their antiproliferative activities were not better due to their low solubility and/or permeability. The stable nitroxides are effective transporter, and helping to increase the solubility of drugs, prompting drug priority through the cancer cell membrane. In order to find effective antitumor drugs selectively targeted to Aruroa A kinase, three series of stable nitroxides labeled pyrimidines, will be designed, synthesized, and evaluated for their biological activities including enzyme assays, cellular assays, antitumor activities in vitro and in vivo, and the mechanism of action. This project will provide a promising direction to find new targeting antitumor drugs.

极光（Aurora）激酶是一类新型的苏氨酸/丝氨酸蛋白激酶，在中心体复制、两极纺锤体形成、染色体重排和染色体检查点监测等有丝分裂过程中发挥着至关重要的作用，是当前抗癌药物研发的重要靶标之一。2,4-双芳基取代的嘧啶类化合物是一类有效的极光激酶A抑制剂，但由于其溶解性和/或膜穿透力差，导致在细胞体内的活性较低。稳定氮氧自由基作为有效的药物转运体，能提高药物的溶解性，并促使药物优先穿过癌变细胞膜。本项目拟设计、合成一系列稳定氮氧自由基标记的嘧啶类化合物，通过对其膜穿透能力、抑酶活性、体内外抗肿瘤活性及作用机制等进行系统研究，以期发现具有开发价值的极光激酶A抑制剂。本项目的实施将为进一步研发新型靶向抗肿瘤药物提供一条新思路。

Aurora激酶是一类新型的苏氨酸/丝氨酸蛋白激酶，在中心体复制、两极纺锤体形成、染色体重排和染色体检查点监测等重要的有丝分裂过程中发挥着至关重要的作用，是研发抗癌药物的重要靶标之一。本项目合成了四类含有稳定氮氧自由基的2,4-双芳基取代的嘧啶类化合物，通过其酶抑制实验、细胞毒实验、顺磁谱、溶解性和脂水分配系数等理化常数的测定实验等，发现稳定氮氧自由基作为有效的药物转运体，引入到嘧啶类骨架上不仅能增强化合物对Aurora-A激酶的抑制活性，还能提高化合物的溶解性，并促使药物优先穿过癌变细胞膜。其中，化合物TM26对体外Aurora-A和Aurora-B激酶的IC50分别为0.061和2.55 nM，而阳性对照药VX680相应的IC50分别为0.95和14.7 nM；TM26对HeLa、A549、HepG2和LoVo等四种癌细胞的GI50值分别为1.2、1.1、1.2 μM和7.3 μM； TM26在裸鼠子宫癌模型中，给药剂量由30 mg/kg 提高到50 mg/kg给药14天后，肿瘤抑制率由34%提高至65%，且对裸鼠的体重的影响小于VX-680。作用机制研究表明，化合物TM26使Aurora A的底物蛋白Bora、TPX2和驱动蛋白Eg5等表达水平的下降明显；同时通过对CyclinB1和cdc2等蛋白的表达抑制，将肿瘤细胞周期循环阻断在G2/M期。此外，化合物TM 26还对VEGFR-2有显著的抑制活性，并对癌细胞的侵袭、迁移及血管生成有明显的抑制作用。本项目的实施印证了稳定氮氧自由基的引入，有助于提高目标化合物的酶抑制活性和抑瘤活性，且改善化合物的溶解性的假设。为进一步研发新型靶向抗肿瘤药物提供一条新思路。