去泛素化酶USP4在头颈鳞癌细胞凋亡中的功能与分子机制

发布时间：2018-05-26 08:45

本文选题：泛素特异性蛋白酶4(USP4) + 受体相互作用蛋白1(RIP1)　；参考：《山东大学》2013年博士论文

【摘要】：背景头颈鳞状细胞癌(head and neck squamous cell carcinoma, HNSCC)是耳鼻咽喉头颈外科临床工作中最常见的恶性肿瘤,也是发病率和病死率均较高的一类恶性肿瘤,阐明其发生、发展机制并尽早诊断、尽早治疗是提高治疗效果的关键。因此,更深入的理解头颈鳞状细胞癌分子水平的异常,有助于我们发展出针对这类肿瘤的新的诊断及治疗手段。肿瘤的发生、发展与细胞凋亡受到抑制密切相关。细胞凋亡是一种重要的细胞应答机制,通过程序性清除机体不再需要的或异常的细胞,细胞凋亡在胚胎系统发育期的肢体塑形、组织平衡的动态调节中发挥至关重要的作用。NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells)细胞信号通路活化及其上游信号分子的泛素化或去泛素化调节在细胞凋亡调控中发挥重要作用。肿瘤坏死因子(tumor necrosis factor, TNF)是一类重要的调节因子,参与了细胞凋亡的调节以及炎症和肿瘤发生过程,目前认为在多种人类疾病的发病机制中都有TNF参与。TNF-α与其1型受体(TNF receptor type1, TNF-R1; CD120a; p55/60)结合后,能够激活NF-κB细胞信号通路促进细胞生存,或者诱导死亡信号促进细胞凋亡,目前研究认为上游的信号分子受体相互作用蛋白1(receptor-interacting protein1, RIP1)的泛素化修饰状态能够动态调节细胞生存信号抑或细胞凋亡信号之间的平衡,在细胞凋亡的调控中具有重要作用。泛素化(ubiquitination)修饰是近年来生命科学研究的重大成果,参与调节抗原提呈、信号转导等多种生理过程,亦是研究、开发新药物的潜在靶点。泛素是一种由76个氨基酸组成的高度保守的多肽,因其广泛存在于从酵母到人类各类细胞而得名。泛素-蛋白酶体途径是细胞内重要的蛋白质质控系统,通过K48位泛素化修饰介导底物经蛋白酶体降解。此外包括细胞凋亡信号在内的许多信号通路关键分子的活化需要K63位泛素化修饰。近年研究发现泛素化状态的改变与多种恶性肿瘤的发生发展密切相关。蛋白分子的泛素化及去泛素化分别通过众多的E3泛素连接酶(E3ligases)及去泛素化酶(deubiquitinating enzymes, DUBs)介导。去泛素化酶可以把泛素或泛素样蛋白从目标蛋白中去除而完成去泛素化过程。泛素特异性蛋白酶4(ubiquitin specific protease4, USP4)被认为能够促进TRAF2(TNF receptor-associated factor2)、TRAF6(TNF receptor-associated factor6)及TAK1(transforming growth factor-β-activated kinase1)等信号分子K63位连接的去泛素化,以及通过K48位去泛素化稳定相关分子。目的本研究课题使用下咽癌细胞株FaDu和人胚肾细胞株HEK293及免疫共沉淀、报告基因分析、体外泛素化等技术分析USP4在人类头颈鳞癌组织及癌旁正常对照组织中表达水平的差异,阐明USP4是否参与TNF-a诱导的细胞凋亡并揭示其分子机制。方法 1.研究USP4在人类头颈鳞癌中的表达 2.研究USP4对TNF-a诱导的头颈鳞癌细胞(FaDu细胞)凋亡的影响 3.研究USP4调控TNF-a诱导的细胞凋亡的具体分子机制结果 1.研究发现USP4在人类头颈鳞癌组织及癌旁正常对照组织中表达水平有明显差异,USP4在人类头颈鳞癌组织中的表达较癌旁正常对照组织显著上调。 2.在TNF-a诱导的FaDu细胞凋亡研究中发现USP4能负向调节NF-κB信号通路活性,促进TNF-α诱导的FaDu细胞凋亡。 3.在具体分子作用机制研究中发现USP4的催化底物分子为RIP1,USP4能够K63位去泛素化聚泛素化修饰的RIP1从而促进TNF-α诱导的细胞凋亡。结论 USP4在人类头颈鳞癌组织中过度表达。USP4能够负向调节RIP1介导的NF-κB信号通路激活。USP4能够促进TNF-α诱导的细胞凋亡。USP4能够作用于RIP1并K63位去泛素化聚泛素化修饰的RIP1。USP4在人类头颈鳞癌中扮演了一个肿瘤抑制因子的角色,可能作为一个潜在的治疗分子靶点。
[Abstract]:background
Head and neck squamous cell carcinoma (head and neck squamous cell carcinoma, HNSCC) is the most common malignant tumor in the clinical work of Otolaryngology Head and neck surgery. It is also a kind of malignant tumor with high morbidity and mortality. It is the key to improve the therapeutic effect by clarifying its occurrence, development mechanism and early diagnosis. Understanding the molecular abnormalities of head and neck squamous cell carcinoma can help us develop new diagnostic and therapeutic approaches for such tumors.
The occurrence and development of tumor are closely related to the inhibition of cell apoptosis. Apoptosis is an important mechanism of cell response. Through procedural clearance of the cells no longer needed or abnormal, apoptosis plays a vital role in the body shaping of the embryonic development stage and the dynamic regulation of tissue balance,.NF- kappa B (nuclear F). Activation of actor kappa -light-chain-enhancer of activated B cells) cell signaling pathway and the regulation of ubiquitination or ubiquitination of upstream signal molecules play an important role in the regulation of cell apoptosis.
Tumor necrosis factor (TNF) is a kind of important regulatory factor, which participates in the regulation of apoptosis and the process of inflammation and tumorigenesis. At present, it is believed that TNF is involved in the combination of.TNF- alpha and its 1 receptor (TNF receptor Type1, TNF-R1; CD120a, p55/60) in the pathogenesis of various human diseases. Kappa B cell signaling pathway promotes cell survival, or induces death signals to promote cell apoptosis. The current study suggests that the ubiquitination of the upstream signal receptor interaction protein 1 (receptor-interacting protein1, RIP1) can dynamically regulate the balance between cell survival signals or apoptosis signals, and in cell apoptosis It plays an important role in the regulation and control.
Ubiquitination (ubiquitination) modification is a major achievement in the research of life science in recent years. It participates in many physiological processes, such as regulating antigen presentation, signal transduction and other physiological processes. It is also a potential target for developing new drugs. Ubiquitin is a highly conserved polypeptide of 76 amino acids, because it exists widely in all kinds of cells from yeast to human. The ubiquitin proteasome pathway is an important protein quality control system in cells that mediates the degradation of the substrate through the proteasome through the K48 ubiquitination modification. In addition, the activation of many key signaling molecules, including the apoptotic signal, requires K63 ubiquitination.
Recent studies have found that changes in ubiquitination are closely related to the development of a variety of malignant tumors. Ubiquitination and ubiquitination of protein molecules are mediated by numerous E3 ubiquitin ligase (E3ligases) and deubiquitinating enzymes (DUBs). Ubiquitin or ubiquitin like proteins can be used to remove ubiquitin or ubiquitin like proteins from target proteins The removal of ubiquitin specific protease 4 (ubiquitin specific protease4, USP4) is considered to be able to promote the ubiquitination of TRAF2 (TNF receptor-associated FACTOR2), TRAF6 (TNF receptor-associated factor6), and other signaling molecules. And to stabilize the related molecules through the ubiquitination of K48 bit.
objective
This study used hypopharyngeal carcinoma cell line FaDu and human embryo kidney cell line HEK293 and immunoprecipitation, reported gene analysis, in vitro ubiquitination and other techniques to analyze the difference in expression level of USP4 in human head and neck squamous cell carcinoma tissue and normal control tissue adjacent to cancer, and to elucidate whether USP4 participates in TNF-a induced apoptosis and reveals its molecular mechanism.
Method
1. study of the expression of USP4 in human head and neck squamous cell carcinoma
2. to study the effect of USP4 on TNF-a induced apoptosis in head and neck squamous cell carcinoma (FaDu cells).
3. to study the specific molecular mechanism of USP4 regulating TNF-a induced apoptosis.
Result
1. the expression level of USP4 in human head and neck squamous cell carcinoma tissues and normal control tissues adjacent to cancer was significantly different. The expression of USP4 in human head and neck squamous cell carcinoma was significantly higher than that of normal control tissue adjacent to cancer.
2. in the study of TNF-a induced FaDu cell apoptosis, USP4 can negatively regulate the activity of NF- kappa B signaling pathway and promote TNF- induced apoptosis of FaDu cells.
3. in the study of specific molecular mechanism, the catalytic substrate molecules of USP4 are found to be RIP1, and USP4 can be K63 to ubiquitin polyubiquitin modified RIP1 to promote apoptosis induced by TNF- a.
conclusion
The overexpression of.USP4 in human head and neck squamous cell carcinoma can negatively affect the activation of.USP4 in RIP1 mediated NF- kappa B signaling pathway to promote TNF- alpha induced apoptosis,.USP4 can act on RIP1 and K63 bit ubiquitination polyubiquitin modification plays a role as a tumor suppressor in human head and neck squamous cell carcinoma. As a potential therapeutic molecular target.
【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：R739.6

【相似文献】