基于自组装的多重靶向抗肿瘤多肽的设计与生物活性研究

Anticancer peptide is one of the hot topics in the research and development of anticancer drugs, however, the stability and targeting are always problems to limit their research and development and clinical application. The main purpose of this project is to design multi-targeting anticancer peptides based on peptide self-assembly. The in vivo stability of anticancer peptides is effectively improved by forming highly ordered self-assembly structures; meanwhile, targeting peptides which can bind the tumor-cell-specific receptors were linked or inserted to target tumor microenvironment; peptide monomers of the self-assembled structure can be responsively dissociated in the tumor microenvironment, and thus increase their activity; in addition,cleavage sites of the tumor-overexpressed proteases are added to the anticancer peptides which in further enhance the activity of the peptides to specific tumor cells; therefore, through the above self-assembly-based peptide design, anticancer peptides acquire improved stability and multi-targeting ability. For the designed anticancer peptide, it can be simultaneously served as a monomer molecule of the self-assembly structure, a tumor targeting molecule and an anticancer effector molecule. This provides a new strategy of peptide design for improvement of the stability and targeting of peptide drugs.

抗肿瘤多肽是目前抗肿瘤药物研发的热点之一，然而其稳定性和靶向性一直是限制这类多肽药物研发与临床应用的主要问题。本课题旨在设计基于多肽自组装的多重靶向抗肿瘤多肽。抗肿瘤多肽分子通过自组装相互作用形成高度有序的自组装体，能够有效提高抗肿瘤多肽药物在体内的稳定性；同时多肽分子中连接或插入肿瘤靶向多肽的序列，通过靶向肿瘤细胞表面的特异受体，从而获得靶向肿瘤微环境的能力；而多肽自组装体在肿瘤微环境中的响应性释放，则可增强抗肿瘤多肽在肿瘤微环境中的活性；在多肽分子中加入肿瘤过表达蛋白酶的酶切位点，则可进一步增加抗肿瘤多肽对特定肿瘤细胞的活性；由此通过上述基于自组装的抗肿瘤多肽的设计，可以提高抗肿瘤多肽的稳定性并使其具有多重肿瘤靶向能力。本课题所设计的抗肿瘤多肽，可同时作为自组装体的单体分子，肿瘤的靶向分子以及抗肿瘤的效应分子，这为抗肿瘤多肽的设计，提高多肽药物的稳定性与靶向性提供了一种新的研究思路。

肿瘤是目前严重威胁人类生命健康的疾病之一，然而肿瘤的特效药物却仍然缺乏。随着精准医学的兴起，肿瘤靶向治疗药物的研发成为重点，多肽抗肿瘤药物是人们十分关注的突破方向之一。本项目以抗肿瘤多肽为主要研究对象，结合多肽分子的多功能性，设计多重靶向自组装抗肿瘤多肽，用于肿瘤的靶向治疗。本论文结合计算机分子模拟技术，首先建立了抗肿瘤多肽的自组装模拟方法，以及多肽与膜相互作用的模拟体系，深入阐明多肽自组装机理，并指导自组装多肽的分子设计。其次，结合课题组已有的研究成果和文献检索结果，设计并筛选了新的抗肿瘤多肽ZXR-1和ZXR-2，并对其作用机理进行了深入研究，为多重靶向自组装多肽的设计奠定了基础。最后在多重靶向自组装抗肿瘤多肽的设计上采用两种方案，分别设计了多重靶向自组装线性多肽和多重靶向自组装套索多肽。通过对前者的研究，初步探索了将主动靶向序列、特异酶切位点、活性多肽通过自组装有机结合的方式，获得具有良好自组装能力和抗肿瘤活性的线性多肽。在这组多肽中，能有效地将被动靶向（纳米颗粒的EPR效应）、主动靶向（RGD序列）结合到自组装多肽纳米颗粒上。对于多重靶向自组装套索多肽的研究（LASAP），开辟了一种新颖的抗肿瘤多肽设计方案。LASAP多肽有效地将iRGD，人胰激肽释放酶-2（hK-2）的酶切位点，pH敏感性抗肿瘤多肽通过分子自组装有机地结合到单一的多肽。该多肽除综合了多种肿瘤靶向策略之外，更表现出显著增强的血清稳定性，因此代表了一种十分具有应用前景的靶向抗肿瘤多肽药物的设计。综上，本项目系统地研究并建立了多重靶向自组装多肽的设计方法，并对多重靶向自组装线性多肽和多重靶向自组装套索多肽分别进行了研究，筛选出两组具有临床应用前景的多重靶向自组装抗肿瘤多肽，既为抗肿瘤多肽药物的设计提供了一个新的思路，也为多肽药物研发提供了理论和实验基础。