NatD调节Slug基因表达促进肺癌细胞上皮间质转化

N-terminal alpha-acetylation is one of the most common protein modifications in eukaryotes which plays an important role during the process of life, and is mediated by N-terminal acetyltransferases (NAT). NatD is one of the NAT family members and can acetylate the N-terminal of histone H4. This project is going to analyze the effects of NatD on migration, invasion and metastasis of human lung cancer cells and related gene expression changes, histone modification changes, and signal transduction pathways, thus revealing a novel mechanism underlying the epithelial-to-mesenchymal transition (EMT). NatD-mediated acetylation of histone H4 regulates the gene expression of Slug specifically, and the crosstalk and collaboration between N-terminal alpha-acetylation of histone H4 and other modifications of histone H4 (such as H4S1p and H4R3me2s etc.) will be demonstrated. The recognition characteristics of N-terminal non-actylation of histone H4 will be also decoded. On the basis of these, combining the clinical analyses of patient data, we will verify the biological role of NatD in vivo with animal experiments. All together, this study will help rationalize NatD as a potential novel target for lung cancer therapy.

蛋白质N-末端alpha-乙酰化是真核生物最广泛的蛋白修饰之一，对生命过程具有重要调节作用，由N-末端乙酰转移酶（NAT）催化介导。NatD是NAT家族成员之一，能催化组蛋白H4的N-末端发生alpha-乙酰化。本项目拟应用人肺癌细胞为研究对象，系统分析NatD对肺癌细胞迁移、侵袭及转移能力的影响与基因表达变化、组蛋白修饰标记变化以及相关信号通路的关系，阐明上皮间质转化（EMT）过程的新调节机制。NatD介导的组蛋白H4　N-末端alpha-乙酰化对Slug基因表达的特异调控以及与组蛋白H4其它修饰标记（H4S1p、H4R3me2s等）相互交流与协调作用将被解析，组蛋白H4 N-末端非乙酰化的识别模式也将被破解。在此基础上，结合临床病例分析数据并对NatD的调节作用进行动物体内实验，验证NatD的生物学新功能。这些研究将为NatD作为一个潜在肺癌治疗新靶点提供理论依据。

蛋白质N-末端alpha-乙酰化是真核生物最广泛的蛋白修饰之一，对生命过程具有重要调节作用，由N-末端乙酰转移酶（NAT）催化介导。NatD是NAT家族成员之一，能催化组蛋白H4的N-末端发生alpha-乙酰化。该研究应用生物化学、分子生物学及表观遗传学等方法，结合临床病例分析验证，首次系统地阐明了N-末端alpha-乙酰基转移酶NatD在肺癌侵袭转移中的新机制。研究发现NatD可以激活细胞EMT过程重要转录因子Slug的表达，从而促进肺癌细胞发生EMT转化，导致肺癌细胞的迁移和侵袭能力增强。NatD在细胞内催化组蛋白H4发生N-末端alpha乙酰化修饰（Nt-ac-H4）；同时还发现该修饰与CK2a催化的组蛋白H4第一位丝氨酸磷酸化修饰（H4S1ph）存在拮抗关系。在肺癌细胞中，NatD的干扰表达降低Slug基因启动子区域的Nt-ac-H4水平，能促使CK2a结合到组蛋白H4的N-末端，催化生成H4S1ph修饰并影响组蛋白其它修饰，如H4R3me和H4K5ac等，从而抑制Slug基因的表达，最终调控下游关键粘附和迁移分子如E-cadherin、N-cadherin及Vimentin等的表达。这些研究将为人类肺癌疾病的治疗提供新策略，为NatD 作为一个新的潜在肺癌治疗靶点打下了理论基础。