多肽纳米聚集体的分子调控及其抗肿瘤效应研究

Peptide is very important probes targeting tumor antigens. Peptide nano-aggregates can improve the binding affinity and selectivity to the tumor associated antigens, and can also enhance the anti-tumor effect. However, the mechanism for the tumor antigen recognition effect of the peptide nano-aggregates is not clear yet, and it is also challenging to improve affinity and selectivity to tumor antigen by molecular modulation. This project will focus on the key scientific problems on the molecular regulation mechanism and anti-tumor effect of the peptide nano-aggregates. We will systematically study the assembly structures, aggregation dynamics of the peptide nano-aggregates, and their anti-tumor effect by using scanning tunneling microscopy (STM), fast-scan atomic force microscopy (AFM), AFM-based quantitative nanomechanical measurement (QNM), surface plasmon resonance imaging (SPRi), spectroscopic methods and cell biology technologies. The research content will include: the molecular structure and dynamics of peptide nano-aggregates, design and screening of peptide with high affinity and high selectivity to the tumor surface antigen, the molecular modulation of assembly structure and the assembly dynamics of the peptide aggregation, and the evaluation of anti-tumor effect and biosafety of peptide nano-aggregates at cellular and animal levels. The modulation mechanism established in this project will be beneficial for developing new anti-tumor peptide nano-aggregates， and exploring new approach for tumor therapy based on peptide nano-aggregates.

多肽是重要的靶向肿瘤抗原的探针，而多肽纳米聚集体能够提高对肿瘤相关抗原靶蛋白的亲和力和选择性，并且可以提高对肿瘤的杀伤能力，然而其识别抗原的机理不明确，并且如何通过分子调控提高其与抗原的亲和力和选择性也存在挑战性。本项目将针对多肽纳米聚集体的分子调控机制和抗肿瘤效应这一关键科学问题，利用扫描隧道显微技术（STM）、快速扫描原子力显微技术（AFM）、基于AFM的定量纳米力学测量技术（QNM）、表面等离激元共振成像技术（SPRi）以及其他谱学、细胞生物学技术等，进行多肽纳米聚集体的结构研究、设计和筛选对肿瘤表面抗原高亲和力和高选择性的多肽、利用小分子对多肽纳米聚集体的组装结构和组装动力学进行调控、并在细胞和动物水平评价多肽纳米聚集体的抗肿瘤效应、生物安全性及其机制。通过本项目研究有望发展新的多肽纳米聚集体调控机制，发现新型的抗肿瘤多肽纳米聚集体，为探索基于多肽纳米聚集体的肿瘤治疗途径提供基础。

利用快速扫描原子力显微镜(Fastscan AFM)对淀粉样多肽自组装进行原位聚集动力学和原位结构转变的研究，进而揭示淀粉样多肽成核和纤维增长的过程。设计了趋化因子受体（CXCR4）、表皮生长因子受体（EGFR）等的靶向多肽，并且构建了CXCR4靶向多肽E5与乙酰化的五代树枝状分子PAMAM G5（PAC80）的复合物，以纳米聚集体的形式提高E5多肽对CXCR4阳性细胞的亲和力，抑制细胞的迁移。在EGFR靶向多肽的载体设计及胶质瘤和三阴性乳腺癌治疗研究方面，筛选出EGFR高亲和力高特异性多肽EP-1和EBP-1，建立可跨血脑屏障的药物递送系统，进行胶质瘤的靶向治疗，同时，利用多肽功能化树枝状分子进行三阴性乳腺癌靶向治疗，提高了化疗药物的靶向性和治疗疗效。完成了项目计划书的研究目标。. 此外，还构建了能够响应肿瘤乏氧微环境且在肿瘤原位持续产氧的纳米药物递送体系，改善肿瘤原位乏氧状态，增强肿瘤光动力治疗效果，从而显著抑制小鼠肿瘤细胞增殖及转移。此外，发展了基于微球辅助流式细胞术的细胞外囊泡检测纳米技术， 上皮细胞粘附分子（EpCAM）和人表皮生长因子受体2（HER2）阳性细胞外囊泡可有效用于乳腺癌的诊断和HER2分子分型，具有很高的高灵敏度和特异性。. 培养博士生5名，发表论文23篇，申请专利5项。