一种MDM2/MDMX双靶点抑制剂的设计、合成及生物活性研究

p53 is an important transcription factor which plays a critical role in the suppression of tumor cells. p53 was mutated in about 50% of tumors cells while in another about 50% of tumor cells with wild type p53, its function was inhibited. MDM2 and MDMX are the primary endogenous inhibitors of p53 which can bind to p53 and inhibit its functions. Small molecules which can bind to MDM2 and MDMX and block their interactions with p53 have great potential to be developed as novel anti-cancer drugs. Multiple MDM2 inhibitors have entered clinical trials, however none of them can effectively inhibit MDMX, therefore, development of dual inhibitors which can inhibit both MDM2 and MDMX has drawn more and more attentions of medicinal chemists. In this project, based upon a MDM2 inhibitor with a benzodiazepine scaffold, we designed a new benzodiazepine analogue through structural modification and proposed to build a compound library by the modifications of the key substituted groups which have key interactions with the protein. The compounds in the library will be screened for their abilities in inhibition of MDM2 and MDMX with the purpose to identify dual inhibitors which can be used for future studies. Successfully carrying out, our efforts will lead to the identification of small molecules which can be used in the development of novel anti-cancer drugs.

p53是对肿瘤有重要抑制作用的转录因子，在大约50%的肿瘤细胞中p53发生了变异，而在另外大约50%的肿瘤细胞中p53的活性则被抑制。MDM2和MDMX是主要的p53的内在抑制剂，它们可以与P53结合并抑制p53的活性，因此与MDM2和MDMX结合并阻断它们与p53相互作用的小分子化合物有被发展成为新型抗肿瘤药物的潜力。目前已有多个MDM2抑制剂进入临床研究，但这些化合物不能有效抑制MDMX，因此研发作用于MDM2和MDMX的双靶点抑制剂是目前抗癌新药研发的热点之一。本项目从一个已知的具有苯二氮卓骨架的小分子MDM2抑制剂出发，首先通过结构改造设计了一个新的模拟苯二氮卓的骨架，随后将通过对与蛋白结合的关键基团进行修饰和改造构建一个小分子化合物库，再通过活性筛选发现新的作用于MDM2和MDMX的双靶点抑制剂。本项目的成功实施，有可能可以发现用于抗肿瘤新药研发的小分子化合物。

TP53基因编码的转录因子p53主要负责监管细胞网络，保护细胞免受不同形式的有害环境的影响，并通过衰老或凋亡机制清除肿瘤细胞以维持正常的生理状态，但其肿瘤抑制功能常常不能得到充分发挥。导致p53失活的主要机制是TP53 基因本身发生突变或缺失，或者p53的功能被其内在抑制剂，如MDM2蛋白等抑制。.本项目主要工作是设计并合成了一类新型的苯二氮䓬结构的MDM2抑制剂，并对其生物活性进行了初步研究。我们对设计的化合物与MDM2结合的模式进行了计算机模拟，对接模型显示这类化合物能够很好的模拟p53的三个关键氨基酸残基与MDM2结合。本项目中合成的化合物与MDM2以及MDMX的结合能力通过基于荧光偏振（FP）的竞争性结合实验进行了测定，其中部分化合物表现出较强的蛋白结合的能力，结合能力最强的化合物与MDM2结合的Ki值接近20 nM。我们采用RS4;11细胞对化合物的细胞活性进行了初步研究，其中部分化合物在抑制细胞增殖的实验中测得的IC50值接近1 μM。这些研究结果表明我们设计并合成的化合物是一类有效的MDM2和MDMX双靶点抑制剂，对这类化合物的进一步研究正在进行中。