大黄素诱发铁死亡抑制口腔鳞癌生长与转移的作用机制研究

Ferroptosis, a new way of programmed cell death, was discovered in recent years. Inhibition of tumor proliferation and metastasis by the induction of ferroptosis is the hotspot in tumor research. Our preliminary data suggested that Emodin could inhibit the proliferation and metastasis by induction of ferroptosis in Oral Squamous Cell Carcinoma (OSCC). Further study showed that Emodin was targeted binding with glutathione S-transferase P1 (GSTP1), leading to the ROS accumulation is the key to ferroptosis in OSCC. However, the target binding sites of Emodin-GSTP1 and specific molecular mechanisms of ferroptosis induced by the binding need to be further explored. Therefore, our further proposal is to analyze the binding sites between Emodin and GSTP1 by structural biology; to determine the molecular mechanism of ferroptosis induced by the target binding of Emodin to GSTP1 in OSCC. Meanwhile, interference of the target binding of Emodin and GSTP1 would be performed in vitro and in vivo to determine the effect of proliferation and metastasis mediated by ferroptosis in OSCC. The molecular mechanism of ferroptosis induced by the targeted binding of Emodin and GSTP1 would be determined as well, so as to provide basic data for the clinical application and the design of anti-tumor drugs targeting GSTP1.

铁死亡是近几年发现的一种新的细胞程序性死亡方式，诱导肿瘤细胞铁死亡进而抑制肿瘤生长与转移是目前肿瘤治疗的研究热点。申请人前期研究发现大黄素（Emodin）能够诱导口腔鳞癌（OSCC）铁死亡发生并抑制肿瘤细胞生长转移；研究还发现Emodin靶向结合谷胱甘肽S转移酶P1（GSTP1）引起的ROS累积是OSCC铁死亡发生的关键，但是Emodin-GSTP1靶向结合位点及结合后诱导铁死亡发生的分子机制亟待阐明。基于此，本项目拟在前期研究基础上，从分子、细胞、动物模型等层面阐明Emodin诱发OSCC细胞铁死亡的作用机制；通过结构生物学的方法解析Emodin与GSTP1的结合位点；并利用体内外模型评估干扰GSTP1与Emodin结合阻断OSCC铁死亡对肿瘤生长转移的影响，以期为Emodin治疗OSCC临床应用及以GSTP1为靶点的抗肿瘤药物设计提供科学支撑。

大黄素是一种潜在的抗肿瘤药物，对口腔鳞癌（OSCC）具有较好的治疗效果，但是其具体的分子机制尚需进一步研究。在本研究中，申请人发现大黄素可以靶向结合谷胱甘肽S转移酶P1（GSTP1）抑制活性氧的清除，诱发OSCC细胞铁死亡。为了进一步增强大黄素在OSCC治疗中的效果，我们利用芦荟大黄素（AE）的光敏剂特性，将AE制备成晶体，然后利用红细胞膜包被并将铁蛋白（Ferritin）修饰在红细胞膜上，制备了仿生材料AE@RBC/Fe NCs。Ferritin可以靶向肿瘤细胞表面高表达的转铁蛋白受体（TFR），不仅为AE@RBC/Fe NCs提供了肿瘤靶向，而且还作为Fe3+缓释的铁池，从而增强了铁死亡和PDT对肿瘤增殖的抑制作用。此外，考虑到RBC膜制备的AE@RBC/Fe NCs在体内可以逃脱免疫清除。另外，AE的最大吸收带位于蓝色区域，使得AE介导的PDT更有利于治疗浅表肿瘤。更重要的是，该纳米平台制备简单，可以巧妙地将光敏剂和铁死亡激活剂集成到一个单一的介质中，促进了铁死亡和PDT协同治疗策略的临床转化。体外和体内实验结果表明，AE@RBC/Fe NCs对两种联合抗肿瘤机制的治疗效果显著增强，为实现PDT/铁死亡的协同治疗提供了良好的前景。