ROS-NOR1调控的肝癌细胞自噬与凋亡的交叉对话及其在肝癌增殖和转移中的作用研究

Hepatocellular carcinoma（HCC） is one of the most common malignant tumors in China. The efficacy of current treatment is very limited, with short patient survival and high mortality rate. Published data as well as our preliminary study indicate that intracellular reactive oxygen species (ROS) behave as a double-edged sword toward tumor cells, promoting tumor cell apoptosis while protecting tumor cells from death by stimulating autophagy. Therefore, the control of tumor cell autophagy vs. apoptosis will likely be a new approach for HCC therapy. It has been found that NOR1 is an oxidative stress responsive protein, which is unregulated by ROS. It has been found that NOR1 is down-regulated in HCC, and overexpression of NOR1 can lead to cell death by suppressing autophagy while promoting oxidative stress-induced apoptosis. Based on these findings, we propose to define the role and molecular mechanism of NOR1 in oxidative stress-induced tumor cell autophagy and apoptosis, and to determine the potential of using NOR1 as a new therapeutic target for HCC in the following specific aims: (1) investigate the effect of ROS on the expression of NOR1 in liver cancer, (2) characterize the dose-time effect of ROS on the induction of liver tumor cell autophagy and apoptosis, and (3) determine the role of NOR1 in HCC growth and metastasis. The success of this study will greatly facilitate our understanding of the molecular mechanisms by which oxidative stress modulates the biological function of HCC cells, and provide scientific basis for the treatment of HCC as well as the development of new drugs.

肝癌是我国常见的恶性肿瘤之一，现有治疗方法效果有限，患者生存期短、死亡率高。文献及申请者前期研究证实，细胞内活性氧（ROS）对肿瘤细胞具有双向调节作用，一方面促进细胞凋亡，一方面激活细胞自噬而保护细胞逃避杀伤。如何调控肝癌细胞的自噬与凋亡将成为治疗的新策略。近来研究表明，NOR1是一种氧化应激反应蛋白，ROS可上调NOR1，过表达NOR1将抑制细胞自噬，促进细胞凋亡。现已证实，NOR1在肝癌中表达下降。据此，本项目在前期研究基础上，以ROS、NOR1、细胞自噬与凋亡为主要研究对象，研究ROS对NOR1的影响及其引发肝癌细胞自噬/凋亡的量效关系、时序特点、在癌细胞增殖转移中的作用，以期揭示NOR1在调控肿瘤细胞自噬/凋亡过程中的作用和分子机制，探讨NOR1作为肝癌治疗新靶点的可行性。本项目将有助于完善氧化应激调控肝癌细胞生物学功能的分子机制，为肝癌治疗和新药研发提供新的思路。

肝细胞肝癌是我国常见的恶性肿瘤，现有治疗方法疗效有限，晚期患者生存期短、死亡率高，亟需探索肝癌发生发展相关的新分子机制，探索可能的新型治疗靶点，为晚期肝癌治疗提供新的治疗策略。.文献及本课题组前期研究证实，细胞内活性氧（ROS）对肿瘤细胞具有双向调节作用，一方面促进癌细胞凋亡，一方面激活细胞自噬而保护癌细胞逃避杀伤。NOR1/OSCP1，是新型氧化应激反应蛋白，最新研究数据显示人肝癌组织中，NOR1表达异常。但NOR1在肝癌细胞增殖发展中的作用尚不清楚。本课题旨在前期研究基础上，深入揭示NOR1在ROS导致的肝癌细胞自噬、凋亡或生长过程中的作用和调控机制，探讨NOR1作为肝癌治疗新靶点的可行性。研究结果将有助于探索氧化应激调控肝癌细胞生物学功能的分子机制，寻找肝癌治疗的新靶点。.本项目实施4年，课题组发现：（1）肝癌组织NOR1表达水平高于癌旁组织；（2）体内外实验显示，NOR1高表达促进肝癌细胞存活；（3）生信分析（KEGG和GO功能富集分析）发现，NOR1共表达基因与线粒体自噬通路高度相关；（4）肝癌细胞系中，上调NOR1表达水平可增强细胞线粒体自噬水平；（5）NOR1通过NOR1-ROS-Pink/Parkin通路促进线粒体自噬升高；（6）NOR1诱导的线粒体自噬增加通过减少细胞色素C释放而抑制细胞凋亡；（7）NOR1通过NOR1-ROS-VEGF途径促进肝癌细胞生长增殖。在本项目基础上，课题组创新性探索国产1.1类新药甲磺酸阿帕替尼与肝癌、NOR1之间的关系，发现阿帕替尼可调肝癌细胞NOR1蛋白表达，阿帕替尼耐药的肝癌细胞NOR1表达亦增高；NOR1可降低肝癌细胞对阿帕替尼的敏感性。这为本课题组进一步研究抗血管生成药物治疗肝癌的耐药机制提供了理论依据，并为探寻新的肝癌治疗策略提供了研究思路。