豆蔻酰化促肝癌的分子机制研究

We focus on the molecular mechanism underlying how post-translational modifications affect liver tumorigenesis. Under the support from the last grant from NSFC, we have achieved the following results: 1) revealed the possible molecular mechanism underlying diabetes boosts liver cancer; 2) uncovered O-GlcNAcylation stimulates liver tumorigenesis via modifications of proto-oncoproteins including YAP; 3) revealed YAP exerts its pro-tumorigeneic roles in liver cancer in a TFCP2-dependent manner. The results of the above studies have been published in Nat Commun, Diabetes, Cell Rep, etc. N-myristoylation is one type of lipid modification, compare to other types of post-translational modifications, N-myristoylation is rarely studied. In our previous studies, we have found that the levels of global N-myristoylation and NMT1, the key enzyme that catalyzes N-myristoylation, were significantly elevated in liver cancer tissues compared to their adjacent controls. Moreover, we found that inhibition of N-myristoylation led to impaired transformative phenotypes of liver cancer cells; however, the related molecular mechanisms remain unknown. This study will use methods including proteomics to reveal potential target proteins of N-myristoylation and the rules involved. Also, we plan to study the fine feedback among the target proteins of N-myristoylation to promote/inhibit liver tumorigenesis. Finally, we also will verify the results from in vitro and in vivo experiments in clinical liver cancer samples. Collectively, this study will uncover the possible molecular mechanism underlying how N-myristoylation affects liver tumorigenesis, and provide evidence that N-myristoylation and its targets can be treated as potential therapeutic liver cancer targets.

申请者一直从事蛋白翻译后修饰影响肝癌发生发展分子机制研究，在前一个国自然青年基金的资助下获以下成果：1）揭示糖尿病促肝癌可能分子机制；2）发现O-连接的N-乙酰葡糖胺化可通过修饰包括YAP在内的原癌蛋白促肝癌；3）发现肝癌内YAP促癌活性依赖于核蛋白TFCP2。相关成果发表于Nat Commun、Diabetes、Cell Rep等期刊。豆蔻酰化是脂质修饰的一种，相对其他翻译后修饰类型较少得到研究。申请者前期研究提示肝癌较癌旁总体豆蔻酰化及豆蔻酰化关键酶NMT1表达水平显著上调，且豆蔻酰化受抑后肝癌细胞恶性表型难以维持，但相关分子机制未知。本课题拟利用蛋白质组学等方法揭示肝癌细胞内潜在豆蔻酰化靶蛋白和对应规律，并深入探索豆蔻酰化靶蛋白间的精细反馈促／抑瘤机制，最后将基础研究的成果于临床肝癌样本中进行验证。本研究将明确豆蔻酰化影响肝癌机制并为豆蔻酰化及靶蛋白作为潜在肝癌治疗靶位点提供依据。

翻译后修饰与肿瘤的发生与发展密切相关，豆蔻酰化是翻译后修饰的一种，但相比其他翻译后修饰，包括泛素化、磷酸化、糖基化等，其对肿瘤的重要性及相关分子机制仍不清。本项目的目的在于探索豆蔻酰化促瘤机制，在本项目的资助下获得以下成果：1）发现肝癌细胞内N-豆蔻酰化可通过POTEE对含有不同结构域的蛋白施行不同调控方式，以不同方式调控肝癌细胞促瘤表型；2）发现肝癌上调蛋白TRIB2可通过PCBP2刺激蛋白酶体活性最终实现GPX4依赖性抗氧化应激；3）发现TRIB2可通过刺激βTrCP依赖的对TFRC的降解作用抑制肝癌细胞铁死亡发生；4）发现肺腺癌外泌体有下降肿瘤细胞对铁死亡敏感性作用；5）发现肝癌内促铁死亡相关转录调控网络，主要涉及由转录因子HIC1及HNF4A介导的不同转录调控平衡；6）发现铁蛋白轻链转录受抑制后可增强铁死亡敏感性；7）发现肝癌细胞中YAP的ISG化可促糖代谢；8）发现一种可利用代谢相关基因预测肝癌预后情况的新方法。在此基础上项目负责人以通讯作者发表第一标柱本项目论文4篇，第三标柱本项目论文4篇。发表的期刊包括Cancer Commun（IF: 15.283）、Redox Biol（IF: 10.787）、Cell Death Dis（IF: 9.685）、Cell Death Discov （IF: 7.109，2篇）等，培养硕士研究生4名，获授权发明专利1项，另有1项发明专利已申请正在受理中。综上所述，本项目已完成既定的各项指标。