抗肿瘤肽修饰的仿生矿化硒掺杂纳米钙磷材料用于抗肿瘤和促骨修复研究

The selenium-doped hydroxyapatite (Se-HA), one typical representative of selenium-doped calcium-phosphate biomaterial, shows great promise of simultaneously defect repair of osteosarcoma resection and tumor recurrence inhibition. However, the current research of Se-HA paid too much attention on anti-tumor somehow ignored bone repair. Herein we design and fabricate an anticancer peptide modified biomimetic mineralized Se-HA (ACP-BM-Se-HA). Collagen is used as a template to induce mineralization through an LSS reaction, which leads to natural bone-like microstructure formation, significant biocompatibility improvement, as well as sufficient active groups for further conjugation of anticancer peptide (ACP). In this project, two representative ACPs, MSP-4 with osteosarcoma apoptosis-inducing capacity and LL37 with immunoregulatory and bone repair functions are selected due to their unique biological potential. The introduction of these two ACPs will not only promote material-cell interaction by changing the surface charge of the Se-HA, but also enhance anti-tumor and bone repair properties. We will carry out in vitro cell experiments and in vivo assays including in situ osteosarcoma recurrence inhibition and bone defect repair, to systemically evaluate the resulting performance of ACP-BM-Se-HA. This project is aimed to provide fundamental theoretical support for developing novel materials and strategies for clinical osteosarcoma therapy.

以含硒羟基磷灰石 (Se-HA) 为代表的硒掺杂钙磷生物材料，为同步实现骨肉瘤切除后的骨缺损修复和肿瘤复发抑制提供了新策略。然而现有的Se-HA设计、制备和功能评价往往关注抗肿瘤方面，忽略了促骨修复功能。本项目首次提出一种抗肿瘤肽修饰的仿生矿化Se-HA纳米材料，以胶原作为模板在LSS体系中矿化，一方面形成类天然骨的微观结构，提高生物相容性；另一方面提供大量活性基团，有利于抗肿瘤肽的表面修饰。课题针对肿瘤抑制和骨缺损修复，分别选择了具有骨肉瘤凋亡诱导作用的MSP-4及免疫调节和促骨修复功能的LL37两种抗肿瘤肽。它们的引入不仅能改变材料表面电荷特征，促进材料-细胞相互作用；还能凭借各自的生物学功能，增强材料的抗肿瘤和促骨修复活性。课题通过体外细胞实验及体内骨肉瘤复发抑制、骨缺损修复综合研究考察和评价新材料的双功能性，将为发展新一代骨肉瘤临床治疗材料和策略提供重要理论基础。

仿生材料已在组织工程领域被广泛开发应用，但是它们在癌症等慢性疾病诊疗中的前景却被忽视。鉴于硒掺杂羟基磷灰石(SeHA)已被证实可通过硒的化疗效果和羟基磷灰石的促骨修复功能，在骨肿瘤术后治疗中发挥潜在的双重作用。本项目通过制备工艺探索，最终利用LSS法在使用和脱离一型胶原大分子模板的情况下分别制备了两种模拟天然骨有序多级结构的SeHA：C-SeHA和B-SeHA。通过与非仿生结构的SeHA进行对比，发现仿天然骨多级结构显著提升了材料的生物学活性：B-SeHA显示出更加高效的细胞内吞，细胞内降解和Se释放，刺激肿瘤细胞生成了更为过量的ROS，进而介导更为显著的JNK通路的激活以及Akt/mTOR通路的抑制，最终诱导更为剧烈的细胞自噬和caspase依赖的细胞凋亡。进一步地，课题选择了具有骨肿瘤凋亡诱导作用的MSP-4及免疫调节和促骨修复功能的LL27两种抗肿瘤肽(ACP)，利用酰胺反应成功修饰到C-SeHA的表面。体外细胞实验及动物在体研究表明，两种ACP共同修饰后的C-SeHA具有显著增强的抗肿瘤和促骨修复功能。此外，课题还将聚酰胺氨型树枝状分子PAMAM-G3修饰到B-SeHA表面，成功构建了表面富含阳离子的新型cfDNA清除材料，通过抑制cfDNA对TLR9的激活作用，有效减轻了牙周炎相关的牙槽骨损失。课题在构建具有良好生物活性的仿生SeHA的基础上，通过表面修饰改性，增强材料原有的或者赋予新的生物学功能，为开发肿瘤、牙周病等慢性疾病的新型诊疗材料提供了良好的理论与技术支撑。