由肿瘤细胞特异性表达的CYP1酶活化的抗肿瘤前药萘醌肟衍生物的设计合成，活性评价及代谢研究

The potent antitumor activity of natural naphthoquinones has been confirmed by a great deal of research, which also indicated that the pervasive cytotoxicity of these compounds largely confined their further development. Nitric oxide (NO) as a reactive gaseous free radical mediated numerous biological processes. It was also toxic to cancers at elevated levels. Controlled and localized generation of NO to cancer cells is challenging. CYP1, one member of human P450 family, was expressed at a high frequency in several cancer cells but was not detected in corresponding normal ones. The difference in expression provided certain advantages in cancer therapy by the activation of prodrugs only in tumor cells..According to the general structural features of CYP1B1 inhibitors, a series of naphthoquinone oxime derivatives was designed and synthesized with shikonin oxime as a lead. The designed compounds as substrates of CYP1 enzyme could be involved in CYP1-mediated bioactivation in cancer cells and be converted to their active forms including NO and naphthoquinones to increase the target specificity of these two pharmacological active compounds..In this study, the antitumor activity of designed compounds and the binding with CYP1 enzymes and metabolic profile of these ones both in vitro and in vivo will be conducted. The candidate compounds with excellent antitumor activity and selectivity to CYP1 enzymes will be obtained for further development. This study is important for the discovery of “Multi-target Anti-tumor Prodrugs Activated by Specificity Enzyme in Cancer Cell, MAPASE”

天然萘醌类化合物的抗肿瘤作用已被大量研究证实，要解决的关键问题是降低其广泛的细胞毒性，提高对肿瘤细胞的选择性。一氧化氮（NO）的作用是广泛的，NO对肿瘤细胞的杀伤作用也是肯定的，要解决的关键问题是如何使NO在肿瘤细胞中定位释放。细胞色素P450酶的一个亚型CYP1在某些肿瘤细胞中特异性高表达，而在正常组织中几乎没有表达，这种表达的差异为以CYP1为靶酶的抗肿瘤前药设计提供了机遇。本研究在前期研究的基础上，以紫草萘醌肟结构为先导，结合已知CYP1底物的结构特征，设计合成一类结构新颖的作为NO供体的萘醌肟衍生物，使之成为CYP1的良好底物，能在肿瘤细胞中被CYP1活化，释放出NO和活性醌，以解决天然醌类抗肿瘤药物的毒性和NO的定位释放问题。为创制一类“由肿瘤细胞特异性酶活化的多靶点抗肿瘤前药”奠定基础。

细胞色素P450酶的一个亚型CYP1在某些肿瘤细胞中特异性高表达，而在正常组织中几乎没有表达，这种表达的差异为以CYP1为靶酶的抗肿瘤前药设计提供了机遇。本研究在前期研究的基础上，以紫草萘醌肟结构为先导，结合已知CYP1底物的结构特征，设计合成一类结构新颖的作为NO供体的萘醌肟衍生物，使之成为CYP1的良好底物，能在肿瘤细胞中被CYP1活化，释放出NO和活性醌，以解决天然醌类抗肿瘤药物的毒性和NO的定位释放问题。我们建立了适合衍生化的合成方法，共合成了9个系列149个目标化合物，经1HNMR、13CNMR和HRMS确证了其结构，并采用MTT法测定所合成化合物体外对人肿瘤细胞的抑制活性，其中DMAKO-20、IV-7和VIII-20在体外抗增殖实验中对耐药肿瘤细胞表现出显著的抑制作用。我们选择活性相对较好的化合物（VIII-20）进一步研究其抗耐药机制，从已有的实验结果可以推论，萘醌肟可能作为一个前药，首先在CYP1B1酶作用下代谢产生NO及单肟衍生物，然后二者分别作用于各自的靶点，发挥多靶点协同抗肿瘤作用，因而作用更强，又因为该代谢反应是肿瘤特异性的，因而减少了对正常细胞的毒性。与MDR逆转剂相比，1,4-萘醌肟衍生物可直接作用耐药肿瘤细胞，抗耐药活性较强，优势明显，具有进一步的研究价值，为创制一类“由肿瘤细胞特异性酶活化的多靶点抗肿瘤前药”奠定基础。