肝靶向螯合剂在消除铜沉积并恢复铜稳态中的研究

Previous studies have given abundant evidence to support the point that copper overload or copper deposition is one of the most well-known factors which brings about hepatic carcinoma. Clearing away copper deposited in hepatocytes effectively and in time plays an important role to resume the copper metabolism. Moreover, it is the last shelter to prevent hepatocytes from becoming cancerous and diffusing. Unfortunately, effective interventions haven’t come out up to now. The project is about to choose arabinogalactan-protein (AGP) which can distinguish and combine with hepatocytes specifically as a target to couple with some chelation groups via covalent. Such chelation groups can chelate copper specifically and stably, low toxicity, acrossing membrane easily, the most important one is that they have chelating-releasing function. The emerging copper chelants targeting hepatocytes will clear away deposited copper in liver via following means: chelanting copper and clean it up driectly; otherwise, chelants and copper form Cu complex, then, such complex acrosses the membrance and criculate or releases in other cells. Cleaning up copper deposited in hepatocytes in time makes big difference to eliminate the risk of canceration. Nevertheless, it contributes to aggrandize the useness of intracellular copper and renew the balance of copper metabolism in vivo.

大量证据表明铜过载及铜沉积是导致肝细胞癌发生发展的一个重要危险因素。及时并有效的清除肝脏内沉积的铜是恢复铜代谢功能的必要前提，更是遏制肝正常细胞癌化、扩散或预防肝细胞癌的最后屏障，但目前对此尚缺乏有效的干预策略。本项目拟选择对肝细胞具有专一性识别和结合的半乳糖糖蛋白作为靶向单元，并筛选对铜具有高选择性、低毒性、易跨膜及较强螯合性和具有螯合-再释放功能的螯合基团，通过将二者以共价键进行偶联，设计新型的肝靶向型铜螯合剂，将肝细胞内沉积的铜直接螯合清除，或以铜配合物的形式跨膜转运至胞外进行循环或在其它细胞中释放，这不仅能消除肝细胞因铜沉积而造成的致癌隐患，而且对增加铜在胞内的可利用性及辅助恢复体内铜的代谢平衡具有重要意义。

铜在体内的代谢平衡对人体至关重要，当肝组织受到侵袭时，其代谢功能受损将导致铜沉积。大量研究表明铜过载不仅使癌细胞增殖更为迅速，而且还促使癌细胞发生侵袭和转移，因此，通过铜螯合剂“剥夺”癌细胞中的铜来抑制或杀死癌细胞已成为抗癌研究的新策略。.本项目通过螯合基团与靶向单元半乳糖或乳糖酸等共价偶联，合成了具有肝细胞靶向特点的新型螯合剂。通过构建的正常铜含量的细胞模型和高铜细胞模型实验，分析了靶向螯合剂对细胞内-外铜离子的选择性螯合作用，对比螯合剂作用前后不同的细胞体系中胞内铜含量的变化、对细胞内含铜酶如SOD1正常酶活性的影响及细胞内-外铜离子转运效果，验证了螯合剂通过改变胞内铜含量而诱导肝癌细胞的凋亡的研究设想：过量的铜可能是潜在的遏制肝细胞癌化的靶点，而利用铜螯合剂靶向去除肝细胞中沉积的铜也可能成为肝细胞癌预防或治疗的新手段。该新型螯合剂不仅具有靶向性特点，而且具有较好的特异性及低毒性，能高效的清除细胞内的沉积铜，且能迅速降低细胞内的铜含量并促使肝癌细胞凋亡，这为后续靶向螯合剂类药物的开发和应用提供设计参考。此类新型螯合剂在靶向消除肝组织沉积铜方面可能有重要的应用前景，可能成为抑制肝铜相关癌变的一种潜在方法。