琥珀酰化修饰对VDAC1的调控及其在乳腺癌发生发展中的分子机制研究

Breast cancer is a common malignant tumor in women, which is a serious threat to women's health and life. Mitochondria are the key organelles that regulate cell apoptosis and energy metabolism. The dysfunction of mitochondria is closely related to the generation and development of tumor. Mitochondrial pore is an important regulator of mitochondrial function, which mediates the process of apoptosis and transport of material and energy. The mechanism of mitochondrial pore formation and the new post-translational modification of important channel proteins are important scientific issues to be solved. Succinylation is a newly discovered post-translational modification of protein, and is widely involved in important physiological processes, such as cell differentiation and metabolism. We found that the important channel protein VDAC1 can be succinylated, which can promote the formation of its self-oligomerization and mediate cell apoptosis. This project will deeply investigate the effect of VDAC1 succinylation on its stability, localization, oligomerization, interaction with other proteins, and the formation of mitochondrial pore. This study will elucidate the role of VDAC1 succinylation in the generation and development of breast cancer at cellular and overall animal levels. This study will explore the molecular mechanism of this new modification on regulating protein functions, provide a new model for the mechanism of mitochondrial pore formation, provide a theoretical evidence for elucidating the pathogenesis of breast cancer, and provide a new insight and targets for the prevention and treatment of breast cancer.

乳腺癌是女性常见的恶性肿瘤，严重威胁妇女的健康和生命。线粒体是调控细胞凋亡与能量代谢的关键细胞器，其功能异常与肿瘤的发生发展密切相关。线粒体孔道介导凋亡过程及物质能量运输，是线粒体功能的重要调节者。孔道的形成机制和重要孔道蛋白新型翻译后修饰方式是亟待解决的重要科学问题。琥珀酰化是新发现的一种蛋白质翻译后修饰方式，广泛参与细胞分化、代谢等重要生理过程。我们的研究发现，重要孔道蛋白VDAC1能够发生琥珀酰化修饰，该修饰促进VDAC1自身低聚化的形成，并介导细胞凋亡。本项目拟将深入研究琥珀酰化修饰对VDAC1的稳定性、定位、低聚化、与其他蛋白相互作用及线粒体孔道的影响。拟从细胞和动物水平阐明VDAC1的琥珀酰化在乳腺癌发生发展过程中的作用。本研究将揭示琥珀酰化这一新型修饰调控蛋白质功能的分子机理，为线粒体孔道形成机制提供新模型，并为乳腺癌发病机理提供理论依据，为预防、治疗提供新思路和新靶标。

乳腺癌是女性常见的恶性肿瘤，在我国的发病率正逐年上升，在许多大城市已高居女性肿瘤的首位，严重威胁着妇女的健康和生命。VDAC1是位于线粒体外膜上的重要通道蛋白，通过自身形成低聚物、与Bax形成异源二聚体、与ANT和CypD等形成通透性转换孔等多种方式，促进线粒体介导的凋亡，但其作用的分子机制仍不清晰。因此，研究VDAC1的调控机制，是弄清乳腺癌等肿瘤发病机理的重要一环。琥珀酰化修饰广泛参与细胞分化、细胞代谢等重要生理活动。本研究通过免疫印迹、免疫共沉淀、同位素标记的质谱技术和定点突变等实验发现，VDAC1能够发生琥珀酰化修饰，K20是其主要的修饰位点，通过免疫印迹实验发现，琥珀酰化修饰能够增强VDAC1的蛋白稳定性和自身低聚物的形成。另外，通过MTT、Trans-well、TUNEL等实验发现，VDAC1的琥珀酰化修饰能够抑制MCF-7细胞的增殖和迁移，促进凋亡。本研究为阐明乳腺癌等恶性肿瘤的发病机理提供了理论依据，为乳腺癌的预防、治疗提供了新的思路和靶标。