靶向VEGFR-2的II型小分子抑制剂的设计、合成及构效关系研究

Vascular endothelial growth factors receptor-2 inhibitors have been proved as very effective anticancer agents.The vast majority of the known VEGFR-2 inhibitors to date are classified as type I inhibitors. Such inhibitors target the ATP binding pocket in its active conformation of the activation loop. This conformation is normally referred to as DFG "in" based on the position of the conserved triad aspartate-phenylalanine-glycine (DFG) at the entrance of the activation loop. In response to these issues, type II inhibitors bind to and stabilize an inactive kinase form that features the DFG motif in an "out" conformation. The different position of the DFG residues in the "out" form creates a new hydrophobic binding pocket that is adjacent to the ATP-binding site. This pocket, also known as the allosteric site, is characteristic of kinase in an inactive conformation. Compared with type I kinase inhibitors, type II inhibitors have several advantages, including great cellular potency and improved kinase selectivity. ..Based on the crystal structure of the kinase inactive DFG"out"conformation and type II kinase inhibitors pharmacophore, this study will design,synthesis a series of novel compounds with the pyrazolo[3,4-d]pyrimidine scaffold as a novel kinase hinger binding template, evalute the biological activities，and develop three-dimensional quantitative structure-activity relationships ( 3D-QSAR ) .This study may be expected to guide the futher research and development of VEGFR-2 inhibitors

血管内皮生长因子受体-2(VEGFR-2)抑制剂是一种新型的抗肿瘤药物。目前开发的大部分抑制剂是I型抑制剂，深入到ATP结合位点，激酶处于"DFG-in"活性构象，存在选择性差、副作用大等缺点。II型抑制剂诱导位于激酶活化区域保守的DFG序列的运动，激酶处于"DFG-out"非活性构象，并且暴露出一个额外的疏水口袋(变构位点)。除了与ATP结合位点结合外，II型抑制剂还与变构位点结合，因此，具有更高的选择性和有效性。基于激酶非活性"DFG-out"构象的晶体结构和II型抑制剂的药效团模型，本研究将以吡唑并[3,4-d]嘧啶为铰链区结合骨架，设计、合成一系列结构新颖的化合物，测定化合物生物活性，建立三维定量构效关系(3D-QSAR)模型，以指导进一步VEGFR-2抑制剂的研发。

血管内皮生长因子受体-2（VEGFR-2）抑制剂是一种新型的抗肿瘤药物。II型抑制剂除了与ATP结合位点结合外，还与额外的变构位点结合，因此，具有更高的选择性和有效性。本课题采用计算机辅助药物设计手段，如分子对接，研究了小分子化合物与VEGFR-2激酶的不同作用模式，并且用分子动力学模拟和结合自由能计算研究了II型抑制剂对化合物的结构要求，在此基础上以吡唑并[3,4-d]嘧啶为铰链区结合骨架，设计了一系列结构新颖的化合物，分子对接表明设计的化合物能与激酶通过氢键作用和疏水作用结合，随后合成了设计的化合物。对化合物进行了激酶的抑制活性测试和体外肿瘤细胞的活性筛选。实验结果显示：所有合成的目标化合物对激酶VEGFR-2和BRAFV600E以及相应的肿瘤细胞都具有一定的抑制活性，部分化合物的激酶抑制活性和体外肿瘤细胞抑制活性与阳性对照药索拉菲尼相当。本研究为我国开发具有自主知识产权的VEGFR-2和BRAFV600E激酶抑制剂的研究工作提供了合理的设计指导和必要的前期研发基础。