具有靶向肿瘤细胞线粒体控释CO功能的智能纳米药物设计、合成及其抗癌性能和机制研究

CO gas has the anticancer features of selectively killing cancer cells and protecting normal cells. But the uncontrolled uptake and aimless systemic diffusion of CO would lead to low therapy efficacy and potential poisoning risk. Based on that mitochondria is the primary target of CO therapy, this project will design and develop a kind of novel intelligent nanomedicine with dual functions of tumor cell mitochondria-targeted CO delivery and controlled CO release to realize tumor-targeted high-efficacy and low-toxicity CO therapy. This project will synthesize a new type of prodrug with the positive charge and the reactive oxygen species (ROS) responsive CO release feature, take mesoporous silica nanoparticle with the negative charge as carrier, and construct a novel nanomedicine by loading prodrug via electrostatic adsorption and then coating hyaluronic acid (HA) on the surface of mesoporous silica nanoparticle. Tumor cell targeting will be realized by particle size modulation and surface HA modification. The prodrug will be released responsively under the tumor microenvironment, and then accumulate in the mitochondria of tumor cells and finally release CO responsively under the high-ROS microenvironment of mitochondria. We will uncover the performances and mechanisms of sequential multiple targeting delivery and controlled release, and further make it clear that the relationship between the structure and composition of nanomedicine and its performances of tumor targeting and controlled release, providing a clue and theoretical direction for designing novel nanomedicine. We will evaluate the anticancer performances and biosafety of the nanomedicine in vitro and in vivo, and exploit its value in the application for cancer therapy.

CO气体具有选择性杀死癌细胞、并保护正常细胞的抗癌特性；但CO的不可控摄入和全身广泛散布会导致较低的药效和潜在的中毒风险。基于线粒体是CO治疗的主要靶点，本项目将设计开发一类兼具肿瘤细胞线粒体靶向传输、可控CO释放功能的新型智能纳米药物，实现高效、低毒的肿瘤靶向CO治疗。本项目将合成一种带正电、具有活性氧（ROS）响应释放CO特性的新型前药，以带负电的介孔二氧化硅纳米粒作为载体，通过静电吸附进行药物装载，然后包裹透明质酸分子，构建新型纳米药物。通过粒径控制和表面透明质酸改性实现肿瘤细胞靶向，在肿瘤酸性微环境响应性释放前药，前药进一步靶向蓄积于肿瘤细胞的线粒体内、并借助线粒体内高ROS环境响应性释放CO。揭示其连续多次靶向传输与可控释放性能和机制，明确其结构和组成与靶向/控释性能之间的关系，为设计新型纳米药物提供思路和理论指导。评价其体内外抗癌性能和生物安全性，探索其在癌症治疗中的应用价值。

肿瘤细胞的线粒体是CO气体分子抗癌的主要作用，然而CO在体内任意扩散，缺乏肿瘤组织蓄积能力，导致抗癌效果有限。本项目率先提出了“多级分步靶向气体传输”的概念，通过程序化组装策略构建具有靶向肿瘤细胞线粒体、并原位控释CO功能的新型智能纳米药物（FeCO-TPP@MSN@HA），利用解组装策略实现肿瘤组织−细胞−线粒体的多级分步靶向药物传输、以及多级分步可控CO前药释放和CO气体释放。在多种肿瘤细胞和肿瘤鼠模型上验证了多级靶向纳米气体药物具有更高效的肿瘤杀伤效果。细胞能量代谢结果表明，这种增强的抗癌效果归功于其增强了肿瘤细胞线粒体中CO的浓度以及CO对线粒体呼吸功能的抑制作用。多级靶向纳米气体药物不仅有效抑制了B16和4T1肿瘤的生长，还显著抑制了乳腺癌的肺转移，延长了荷瘤鼠的存活时间。本项目提出的多级分步靶向气体传输策略为设计开发新型抗癌药物提供了新的思路。此外，本项目进一步挖掘了更具生物安全性的治疗性气体--氢气，提出了“氢热治疗”和“催化产氢”等新型控释氢气的药物设计策略，引领了氢医学的纳米药物设计理念和生物学效应机制研究的快速发展，为推进纳米气体治疗的临床应用奠定了基础。