双功能基因脱嘌呤脱嘧啶核酸内切酶（APE1）在调控肿瘤细胞电离辐射效应中发挥关键作用。乙酰化修饰是APE1翻译后水平实现其氧化还原和DNA修复活性调节的重要途径，组蛋白去乙酰化酶（HADC）Ⅲ SIRT1是APE1主要去乙酰化酶，三羟异黄酮（GEN）可特异性抑制SIRT1活性。据此我们首先提出APE1乙酰化可能是介导肺癌放疗增敏重要机制，GEN则可通过上调APE1乙酰化调控肺癌放疗敏感性。本项目以APE1乙酰化突变和野生型A549细胞为对象，应用自制APE1乙酰化抗体，观察电离辐射后APE1乙酰化对APE1表达和活性影响，进而研究GEN对电离辐射前后两类细胞APE1乙酰化及增殖凋亡的影响，并通过比较GEN、HADCⅢ和Ⅰ抑制剂烟酰胺、古抑菌素A作用后APE1表达和修复活性变化，探讨GEN调节APE1乙酰化调控肺癌放疗效应机制，为创新性以APE1为靶分子的GEN增敏肺癌放疗转化研究提供依据。

Dual functional gene apurinic apyrimidinic endonuclease (APE1) plays a key role in regulating the ionizing radiation effect of tumor cells. The acetylation modification is reported to be an important way to regulate redox and DNA repair activity of APE1 at its post-translational level. The histone acetylation enzyme Ⅲ SIRT1 is the major enzyme responsible for APE1 acetylation, while genistein (GEN) can inhibit specifically SIRT1. Hence, for the first time, we proposed that it can be an important mechanism for enhancing radiotherapy sensitivity of lung cancer cells via up-regulate the acetylation of APE1 by GEN. In the project, aim to APE1 mutation at acetylation site and wild-type lung adenocarcinoma A549 cells, and use own-preparated antibody of APE1 acetylation, we observed the effect of APE1 acetylation on expression and activity of APE1 after ionizing radiation. Then, this study investigated the influences of GEN on the APE1 acetylation and proliferation/ apoptosis of the two kinds of cells before and after Ionizing radiation. To compare the alteration of APE1 expression and base excision repair activity in A549 cells after treatment of GEN, HADC Ⅲ inhibitors nicotinamide and HDAC I inhibitor song ancient antibacterial A, this study discussed the mechanism of the GEN in the adjustment of the acetylation of APE1 to regulate radiotherapy effect in the lung cancer. Aiming to provide rationales for the translational research on increasing sensitivity of the lung cancer radiotherapy by GEN targeting APE1 acetylation in the project.