The Role of p53-R249S’s GOF in HCC development

p53-R249S GOF 在 HCC 发展中的作用

• 批准号: 10317044
• 负责人: Hua Lu
• 金额: $ 35.16万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10317044
• 关键词: Address; Aflatoxin B1; Area; Asia; Automobile Driving; Binding; Biochemical; Biogenesis; Biological; CDK4 gene; Cell Cycle; Cell Cycle Progression; Cell Nucleus; Cell Proliferation; Cell Survival; Cells; Central Africa; China; Clinical Trials; Combined Modality Therapy; Cyclin D1; Development; Diagnosis; Disseminated Malignant Neoplasm; Dominant-Negative Mutation; Drug resistance; Exposure to; FBXW7 gene; Future; Gene Expression; Genetic; Genetic Transcription; Genomics; Goals; Growth; HBV and Aflatoxin; Hepatitis B Infection; Hepatitis B Virus; Hot Spot; Human; Knock-in; Knock-in Mouse; Knowledge; Light; Link; Liver; Malignant Epithelial Cell; Malignant Neoplasms; Manuscripts; Mediating; Molecular; Molecular Target; Mus; Mutate; Mutation; NIMA; Nuclear; Nuclear Import; Oncogenic; Oncoproteins; Pathway interactions; Patients; Peptidylprolyl Isomerase; Phosphorylation; Phosphotransferases; Play; Primary carcinoma of the liver cells; Protein Biosynthesis; Publishing; Research; Ribosomes; Role; Sequence Analysis; Signal Pathway; TP53 gene; Testing; Therapy trial; Transcript; Tumor Suppressor Genes; c-myc Genes; cancer cell; cancer stem cell; cancer therapy; cell growth; cis-trans-Isomerases; cohort; combinatorial; design; dietary; exposed human population; gain of function; insight; loss of function; mutant; programs; rational design; stem cell division; transcription factor; tumorigenesis

Project Summary This application is proposed to determine the biological role of a specific p53 mutant, R249S (p53-RS), whose Arg 249 is substituted by Ser, in development and progression of hepatocellular carcinoma (HCC) and to divulge molecular mechanisms underlying its gain of function (GOF) crucial for its oncogenic role. Remarkably, p53-RS is highly associated with HCC patients who are often exposed to dietary aflatoxin B1 (AFB1) and infected with Hepatitis Virus B (HBV) in Asia and central Africa, as it is the only hotspot p53 mutation identified among HCC patients. Since genetic knockin of mouse R246S (equivalent to human R249S) without any oncogenic challenges only showed its loss of function (LOF) and dominant negative (DN) effect on cancer development without any GOF activity, it has still remained elusive if p53-RS possesses GOF activity important for proliferation, invasion and tumorigenesis of HCC. If so, what would be the underlying mechanism for this GOF activity. Our recent studies uncovered the unique link of a cell cycle-regulated kinase, CDK4, Cyclin D1(CycD1), a peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1), and an oncoprotein c-Myc with the GOF activity of p53-RS. All of these four oncoproteins, CDK4, CycD1, PIN1, and c-Myc play critical roles in the cell cycle progression and cancer cell proliferation and growth, and are highly expressed in various types of human cancers, including HCC. Our preliminary and published studies showed that CDK4/CycD1 can specifically bind to and phosphorylate p53-RS at its HCC-derived Ser249, and this phosphorylation facilitates p53-RS's PIN1 binding and subsequent nuclear localization. In the nucleus, p53-RS binds to and stabilizes c- Myc by blocking FBW7-mediated degradation, consequently leading to c-Myc activation and increase of synthesis of ribosomal proteins-encoded transcripts. Through these actions, p53-RS executes its GOFs activity crucial for HCC cell proliferation and survival. In light of our preliminary results, we hypothesize a unique mechanism for this p53 mutant's GOF, i.e., substitution of Arg249 with Ser renders this mutant to a new phospohorylation substrate for CDK4/CycD1 during the cell cycle, and phosphorylation at this residue makes p53-RS more accessible for PIN1-binding; As a result, PIN1 facilitates the transport of this mutant p53 to the nucleus where it promotes HCC proliferation by binding to and activating c-Myc, promoting HCC development and progression. We will test this hypothesis by addressing two specific aims: 1) To further decipher biochemical mechanisms underlying the GOF of p53-RS in HCC; 2) To determine if p53-RS's GOF plays a role in HBV-associated HCC development. Completing these comprehensive studies would gain critical information for our better understanding of the unique signaling pathway underlying p53-RS's GOF in HCC development and progression, and also unveil CDK4/CycD1, PIN1 and c-Myc as molecular targets for developing a more effective combinatorial therapy for HCCs that harbor p53-RS.

项目摘要 提出了该应用来确定特定p53突变体R249S（p53-rs）的生物学作用，该突变体的生物学作用 ARG 249用SER，肝细胞癌（HCC）的发育和发展代替 泄露其功能增长（GOF）对其致癌作用至关重要的分子机制。值得注意的是 p53-Rs与通常暴露于饮食黄曲霉毒素B1（AFB1）和 在亚洲和中非感染了丙型肝炎病毒B（HBV），因为它是唯一发现的热点p53突变 在HCC患者中。由于小鼠R246S（相当于人R249）的遗传敲击蛋白没有任何 致癌挑战仅显示其功能丧失（LOF）和对癌症的主要负面影响（DN）影响 没有任何GOF活动的开发，如果P53-RS具有重要的GOF活性，它仍然难以捉摸 HCC的增殖，侵袭和肿瘤发生。如果是这样，这将是什么基本机制 GOF活动。我们最近的研究发现了细胞周期调节的激酶CDK4，细胞周期蛋白的独特联系 D1（CYCD1），肽基 - 丙基顺式跨异构酶NIMA相互作用1（PIN1），以及与癌蛋白C-MYC P53-RS的GOF活性。所有这四种癌蛋白CDK4，CYCD1，PIN1和C-MYC在 细胞周期进展和癌细胞增殖和生长，并在各种类型中高度表达 人类癌症，包括HCC。我们的初步和发表的研究表明，CDK4/CYCD1可以 在其HCC衍生的SER249上特异性结合并磷酸化p53-Rs，该磷酸化促进 p53-RS的PIN1结合和随后的核定位。在细胞核中，p53-rs与C-结合并稳定 MYC通过阻止FBW7介导的降解，因此导致C-Myc激活并增加 核糖体蛋白编码转录本的合成。通过这些动作，p53-rs执行其GOFS活动 对于HCC细胞增殖和存活至关重要。鉴于我们的初步结果，我们假设一个独特的 该p53突变体GOF的机制，即用Ser替换为Arg249，将此突变体呈现为新的 在细胞周期中，CDK4/CYCD1的磷酸化底物，该残基处的磷酸化使得 P53-RS更容易用于PIN1结合；结果，PIN1促进了该突变体p53的运输 核通过结合并激活C-MYC来促进HCC增殖，从而促进HCC的发展 和进展。我们将通过解决两个具体目的来检验这一假设：1）进一步破译 HCC中p53-RS GOF的基础的生化机制； 2）确定P53-RS的GOF是否播放 在与HBV相关的HCC开发中的作用。完成这些全面研究将获得关键 信息以更好地理解HCC中P53-RS的唯一信号通路 开发和进展，还推出CDK4/CYCD1，PIN1和C-MYC作为分子靶标 为具有p53-RS的HCC开发更有效的组合疗法。