以SphK1为靶标的抗肿瘤化合物的设计、合成及生物活性研究

Lipid kinase sphingosine kinase 1 (SphK1) is upregulated in various human tumours and inhibition of SphK1 is considered a novel approach for the treatment of cancers. Despite recent advances in SphK1 inhibitors synthesis and validation, there are no candidate drugs for clinical trials and there are no drugs on the market. In our previous study, we firstly discovered the tetrahydropyrrolidines of the natural product pachastrissamine have the advantage of selective inhibition against SphK1; We also found a potent lead compound SAMS-10 that selectively inhibits SphK1 through an integrated pharmacophore-based and docking-based virtual screening approach. On the basis of these studies, a series of compounds were designed using rational drug design method based on the SphK1’s ligand binging pocket and the chemical structures of pachastrissamine and SAMS-10. The designed compounds will be synthesized based on the synthetic strategies reported previously, and the systematic activity evaluation, structure-activity relationship and drug-like properties of the target compounds will be measured in order to find active compounds targeting SphK1. This project will further enrich the design and synthesis theory of SphK1 inhibitors, and provide a theoretical basis for the discovery of novel lead compounds with high activity. This research will also provide research-related reference materials for the development of new cancer therapeutic drugs targeting SphK1 with independent intellectual property rights.

脂质激酶SphK1在多种癌细胞中高表达，是治疗癌症的理想靶标。目前还没有上市及进入临床研究的SphK1抑制剂。我们前期一方面首次发现了天然产物pachastrissamine的四氢吡咯烷类化合物具有选择性抑制SphK1的优势；另一方面通过基于药效团及分子对接的虚拟筛选方法新发现了选择性抑制SphK1的化合物SAMS-10。基于此，本项目拟基于已经阐明的SphK1晶体结构与化合物pachastrissamine及SAMS-10的化学结构，结合计算机辅助药物设计方法设计合成系列化合物，并对目标化合物进行系统活性评价、构效关系及类药性研究，筛选出靶向SphK1的活性化合物。该项目的实施将进一步丰富SphK1抑制剂的设计及合成理论，为发现高活性新型抑制SphK1的先导化合物提供理论依据，为创制具有自主知识产权的靶向SphK1的临床候选药物提供实验依据和方法学上的借鉴。

鞘氨醇激酶（sphingosine kinases, SphKs）有SphK1和SphK2两种异构体，是调控神经酰胺（ceramide, Cer）、鞘氨醇（sphingosine, Sp）、鞘氨醇-1-磷酸（sphingosine-1-phosphate, S1P）动态平衡的重要限速酶，也是细胞增殖及存活的重要信号分子，在肿瘤、炎症等多种疾病中的作用已逐步被阐明，是癌症等疾病治疗的理想靶点。本项目以前期全合成的天然产物Pachastrissamine及虚拟筛选得到的SAMS-10为靶向SphK1的先导化合物，进行结构修饰及生物活性评价，最终发现的化合物YHR17对SphK1具有理想的抑制活性及选择性（SphK1: IC50 = 0.8 μM, SphK2: IC50 > 100 μM），并对A375（IC50: = 0.7 μM）和HepG2（IC50: = 1.46 μM）等肿瘤细胞具有抗增殖活性，而对正常细胞毒性较弱（IC50: > 100 μM），目前正进行成药性研究。化合物YHR1的盐酸盐（CHJ01）对SphK1具有中等强度的抑制活性（SphK1: IC50 = 8.89 μM, SphK2: IC50 >100 μM），可通过影响大鼠关节炎模型中IL-1β, TNF-α, IL-6的水平从而对类风湿性关节炎具有一定的治疗作用。通过虚拟筛选得到的L-抗坏血酸6-棕榈酸酯（SphK1: IC50 = 6.414 μM, SphK2: IC50 > 100 μM）为后期结构的优化与活性研究奠定了理论与实验基础。通过对先导物SAMS-10进行优化得到的二芳基类化合物虽然对SphK1的抑制活性不理想，但多数化合物对肿瘤细胞具有较优的抑制活性，是后期进行靶点确认、机制研究、创新药物研发的物质基础。