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

p53-R249S GOF 在 HCC 发展中的作用

基本信息

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
项目类别：
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

项目摘要

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.

项目概要该应用旨在确定特定 p53 突变体 R249S (p53-RS) 的生物学作用，其在肝细胞癌 (HCC) 的发生和发展过程中，Arg 249 被 Ser 取代揭示其功能获得（GOF）背后的分子机制对其致癌作用至关重要。值得注意的是， p53-RS 与经常接触膳食黄曲霉毒素 B1 (AFB1) 的 HCC 患者高度相关亚洲和中非感染乙型肝炎病毒 (HBV)，因为它是已发现的唯一热点 p53 突变肝癌患者中。由于小鼠 R246S（相当于人 R249S）的基因敲入，没有任何致癌挑战仅显示其对癌症的功能丧失（LOF）和显性失活（DN）影响尽管 p53-RS 的发育没有任何 GOF 活性，但 p53-RS 是否具有 GOF 活性仍然难以捉摸。 HCC 的增殖、侵袭和肿瘤发生。如果是这样，其根本机制是什么 GOF活动。我们最近的研究揭示了细胞周期调节激酶 CDK4、Cyclin 之间的独特联系 D1(CycD1)、肽基脯氨酰顺反异构酶 NIMA 相互作用 1 (PIN1) 和癌蛋白 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，并在各种类型的细胞中高表达人类癌症，包括肝癌。我们的初步和已发表的研究表明 CDK4/CycD1 可以特异性结合 p53-RS 并在其 HCC 衍生的 Ser249 处磷酸化，这种磷酸化促进 p53-RS 的 PIN1 结合和随后的核定位。在细胞核中，p53-RS 结合并稳定 c- Myc 通过阻断 FBW7 介导的降解，从而导致 c-Myc 激活并增加核糖体蛋白编码转录本的合成。通过这些行动，p53-RS 执行其 GOF 活动对于肝癌细胞的增殖和存活至关重要。根据我们的初步结果，我们假设一个独特的该 p53 突变体 GOF 的机制，即用 Ser 替换 Arg249 使该突变体成为新的细胞周期中 CDK4/CycD1 的磷酸化底物，该残基的磷酸化使得 p53-RS 更容易与 PIN1 结合；因此，PIN1 有助于将该突变体 p53 转运至通过结合并激活 c-Myc 促进 HCC 增殖，促进 HCC 发展和进展。我们将通过解决两个具体目标来检验这一假设：1）进一步破译 HCC 中 p53-RS GOF 的生化机制； 2) 判断p53-RS的GOF是否播放在 HBV 相关 HCC 发展中发挥作用。完成这些全面的研究将获得关键的帮助我们更好地了解 HCC 中 p53-RS GOF 的独特信号通路的信息的发展和进展，并推出 CDK4/CycD1、PIN1 和 c-Myc 作为分子靶标为含有 p53-RS 的 HCC 开发更有效的组合疗法。