谷胱甘肽S转移酶（GST）靶向的新型NO供体型抗肿瘤药物的设计、合成和生物活性研究

Overexpression of glutathione S-transferase (GST) P isozyme in many tumor cells was considered as a possible mechanism of tumor cell drug resistance. In this regard, GST P is emerging as a promising target for managing the development of anticancer agents. Previous research project involved the synthesis of a new series O2-sulfonylethyl protected diazen-1-ium-1,2-diolate compounds. This new series of O2- sulfonylethyl diazeniumdiolate compounds could release NO in a non-physiological alkaline buffer, or in the presence of bases such as the basic natural amino acids Arg and His in PBS at pH 7.4, via a β-elimination cleavage reaction. Further study revealed that that GST P can also active O2-protected compounds to release NO via the same β-elimination pathway. Based on these findings, the concept of O2-sulfonylethyl diazeniumdiolate-based glutathione derivatives was proposed in this project. The preliminary modeling study and in vitro anti-cancer assessment showed that the target compounds which have been successfully synthesized can be activated by GST P and show potent inhibitory activities against cancer cells growth in vitro. The further works include: 1) modifying GSH moiety and diazeniumdiolate secondary amine moiety to improve the selectivity for GST P isozyme and enhance anti-cancer activities; 2) quantitative structure-activity (isozyme selectivity and anticancer activity) relationship study; 3) in vitro and in vivo anti-cancer activity evaluation; 4) possible mechanisms underlying the anti-cancer activity exhibited by O2-sulfonylethyl diazeniumdiolate-based glutathione derivatives. The purpose of the project is to develop a novel NO-donating anti-cancer agents which can be selectively activated by glutathione S-transferase and release NO targetingly to avoid undesired side-effect.

谷胱甘肽S转移酶（GST）P亚型之所以作为一个有前景的抗肿瘤药物的靶点，是因为其在多数肿瘤细胞表面过度表达，且与肿瘤细胞的耐药性密切相关。我们发现，O2-磺酰基乙基偶氮鎓二醇盐可以在碱性条件下或者在碱性氨基酸存在下被活化，发生β-消除反应后，生成偶氮鎓二醇盐片段，进而释放NO。进一步研究表明，GST P酶也可以活化O2-磺酰基乙基偶氮鎓二醇盐衍生物，发生β-消除反应，进而释放NO。基于上述研究，本项目设计、合成O2-磺酰基乙基偶氮鎓二醇盐修饰的谷胱甘肽类似物，前期的计算机模拟及体外活性测试结果已表明，目标化合物作为GST P酶的底物，能特异性地被其活化，并显示了强效的体外抗肿瘤活性。在此基础上，拟进一步优化化合物结构，以提高GST P亚型的选择性和抗肿瘤活性，并进行定性、定量构效关系研究，体内、外抗肿瘤活性及其作用机制研究，为最终获得 GST P靶向的新型NO供体型抗肿瘤药物奠定坚实基础。

谷胱甘肽S转移酶（GST）P亚型之所以作为一个有前景的抗肿瘤药物的靶点，是因为其在多数肿瘤细胞表面过度表达，且与肿瘤细胞的耐药性密切相关。我们发现，O2-磺酰基乙基偶氮鎓二醇盐可以在碱性条件下或者在碱性氨基酸存在下被活化，发生β-消除反应后，生成偶氮鎓二醇盐片段，进而释放NO。进一步研究表明，GST P酶也可以活化O2-磺酰基乙基偶氮鎓二醇盐衍生物，发生β-消除反应，进而释放NO。基于上述研究，本项目设计、合成了一系列O2-磺酰基乙基偶氮鎓二醇盐修饰的谷胱甘肽类似物，并进行了相关的药理学评价，结果如下：.1. 计算机docking结果显示作为GST的底物，HG-25能够和GST P1-1较好的结合，其7位酪氨酸残基的酚氧负离子和化合物HG-25中磺酰基位置的两个氢中的其中一个氢距离仅为 2.7 Å，提示GST P1-1有能力夺取HG-25中磺酰基位置的氢触发β-消除反应后释放NO，从而产生选择性的抗肿瘤作用。.2. 体外抗肿瘤增殖活性测试结果表明，化合物的活性依赖于肿瘤细胞GST的表达和功能。对GST表达高功能强的肿瘤细胞B16和MCF-7显示出较强的体外抗增殖活性，部分化合物的IC50在1 μM以下。.3. 体外抗肿瘤增殖活性测试结果还表明，化合物HG24、27和29对几株耐药肿瘤细胞株显示较强的细胞增殖抑制活性。部分化合物的IC50在1 μM左右。.4. 在甘氨酸部分引入(S)-苯基得到的化合物HG-31并没有像预计的具有GST P1-1的亚型选择性。.5. 活性化合物HG-24的体内急性毒性试验和体内裸小鼠移植瘤抑制试验即将开展。. 通过前期研究和本项目的实施，培养了1名硕士研究生，此外申请与本项目相关的中国专利一项并以得到授权，发表SCI科研论文3篇，中文期刊1篇。