价态调控三氧化二砷前药逐级递进靶向递药系统肝细胞癌胞内转运及其机制研究

Arsenic trioxide (As2O3), an active ingredient of Traditional Chinese Medicine White Arsenic, is a potential agent for anti-hepatocellular carcinoma therapy for long time. However, its clinical application is limited largely because of the poor tumor distribution, high toxicity and serious side effects of the digestive system. In this study, in order to reduce the side effects of arsenic trioxide, a new graded-progressive targeting delivery system will be chosen to respond to the tumor microenvironment with low pH, matrix metalloproteinases and folate receptor. And it could control arsenic in vivo toxicity by changing from the physiological environment to tumor environment, using the characteristic of the more severe toxicity of trivalent arsenic over pentavalent arsenate. Comprehensive considering the properties of As2O3, the process of physiological distribution and the characteristics of hepatocellular carcinoma microenvironment, in the project, we will construct a graded-progressive targeting drug delivery system loaded prodrug of arsenic trioxide with controlled valence, modifying folic acid and cationic cell-penetrating peptide. After multi-level response to the tumor microenvironment, the pentavalent arsenic prodrug is converted to As2O3 and completes drug release in the tumor cells through the agent itself and tumor cell response. In addition, we will build hepatocellular carcinoma patient derived xenografts model and patient-derived organoid model and gene knockout model to study the graded-progressive targeting drug delivery system and the transport mechanisms in vitro and in vivo from the molecular, cellular and animal levels. Our project will provide initial strategy and methods for the precise targeting Traditional Chinese Medicine in hepatocellular carcinoma.

中药砒霜有效成分三氧化二砷（As2O3）对肝细胞癌有良好疗效，但因其分布无特异性，毒性反应明显，易引发消化系统损伤等原因极大的限制其临床应用。本项目旨在改善三氧化二砷的毒副作用，采用响应肿瘤低pH的微环境及基质金属蛋白酶、叶酸受体特异性表达的新型逐级递进靶向递药系统，利用三价砷比五价砷毒性更剧烈特点，从生理病理环境向肿瘤环境转变砷价态，控制体内砷的毒性。本项目整体把握As2O3理化性质、生理分布过程及肝细胞癌微环境特点构建价态可调控的三氧化二砷前药逐级递进靶向递药系统，多级响应肿瘤微环境后在肿瘤细胞内通过递药系统本身将五价砷前药转变为As2O3并完成释药。本项目将构建患者来源肝细胞癌植瘤模型、肝细胞癌患者来源类器官模型与CRISPR/cas9技术构建转基因细胞模型，从动物-细胞-分子三个水平研究载体递进式逐级递进靶向、胞内释药及转运机理，为实现中药肝细胞癌胞内递送和释药提供新策略与新方法。

三氧化二砷( ATO )是传统中药砒霜中的有效成分，对肝细胞癌具有良好的治疗效果。然而，由于其较差的肿瘤分布和高毒性，ATO在临床上的大规模应用受到了严重阻碍。在本项目中，基质金属蛋白酶2（MMP2）响应性裂解细胞穿透肽（PF）和叶酸（FA）共修饰的脂质体包裹的砷酸钙纳米颗粒（FA/PF-LP-CaAs）是基于以下两个考虑而制备的：加速内吞；（2）利用砷在不同价态下的不同毒性，即五价砷可以通过谷胱甘肽在肿瘤细胞中还原为毒性更强的AS2O3。此外，FA/PF-LP-CaAs可被弱酸性肿瘤环境响应性降解，降解产物可在内吞后从溶酶体中逃逸。更为重要的是，根据体内生物分布和药效学研究，载体能够有效地在肿瘤中积聚。此外，与单一修饰的对应物相比，它能够显示出优异的抗肿瘤效果，副作用最小化。因此，本项目提出的基于肿瘤微环境的新策略可以提高肿瘤靶向效率和肿瘤内毒性，为实现中药肝细胞癌内递送和释药提供新策略与新方法。