The genetics of tumor suppression by p53

p53 抑制肿瘤的遗传学

• 批准号: 10636305
• 负责人: Maureen E. Murphy
• 金额: $ 42.22万
• 依托单位: WISTAR INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-04-03 至 2028-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10636305
• 关键词: Adopted; Adrenal Gland Neoplasms; Affect; Age; Alleles; American; Apoptosis; Arginine; Benign; Binding; Biology; Breast Cancer Cell; Breast Cancer Model; CRISPR/Cas technology; Cancer Biology; Cell Line; Cells; Childhood; Clinic; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; Data; Defect; Diagnostic; Disease; Doctor of Philosophy; Family; Generations; Genes; Genetic; Genetic Transcription; Germ-Line Mutation; Glutaminase; Glycine; Goals; HCT116 Cells; Human; Impairment; Incidence; Individual; Inherited; Knock-in; Li-Fraumeni Syndrome; Life; Loss of Heterozygosity; Machine Learning; Malignant Neoplasms; Mediating; Molecular Conformation; Mus; Mutation; NF-kappa B; Neoplasm Metastasis; Oncogenic; Patients; Penetrance; Pennsylvania; Peripheral Blood Mononuclear Cell; Persons; Pharmaceutical Preparations; Philadelphia; Prognosis; Proteins; RNA; Reagent; Research; Risk; Siblings; TP53 gene; Testing; The Wistar Institute; Therapeutic; Transactivation; Tumor Suppression; Tumor Suppressor Proteins; United States; Universities; University Hospitals; Variant; anticancer research; breast cancer progression; cancer risk; chemotherapy; cytotoxicity; gain of function; genetic signature; genetic variant; improved; inhibitor; lymphoblastoid cell line; malignant breast neoplasm; medical schools; mouse model; mutant; neoplastic cell; novel; novel therapeutics; personalized therapeutic; prognostic; senescence; transcriptome sequencing; tumor

Project Summary This submission represents a collaborative application from Maureen Murphy PhD at the Wistar Institute in Philadelphia and Kara Maxwell MD/PhD from the University of Pennsylvania Perelman School of Medicine. The goal is to study the function of a novel p53 mutation that was first discovered in several highly cancer- prone families seen in Dr. Maxwell’s clinic at the Hospital of the University of Pennsylvania. This variant, G334R in p53 protein (G331R in mouse p53) was found in nine different families with multiple cancers in multiple generations, including cousins with pediatric adrenal tumors; the latter are a hallmark of cancer- predisposing mutations in TP53. Moreover, we find that several tumors from these patients show loss of heterozygosity for p53. We show that the G334R variant is impaired for oligomerization, and for the induction of a small subset of p53 target genes, several of which are themselves tumor suppressors (PCLO, PLXNB3, and others). Our functional analyses of the G334R variant suggest that this is not a traditional Li Fraumeni mutant; that is, a mutation that completely inactivates p53 function. Rather, our functional data are most consistent with G334R being a p53 “hypomorph”, or a genetic variant that shows impaired, but not completely inactive, function. Specifically, 1) G334R possesses some ability to suppress colony formation in tumor cells, though it shows less ability than wild type p53; 2) G334R is fully capable of transactivating the overwhelming majority of p53-regulated genes, but is defective in the transactivation of approximately two dozen p53 target genes; 3) the peak incidence for breast cancer in G334R individuals is between the ages of 35-55, while most cases of Li Fraumeni occur between the ages of 20-40, and sporadic breast cancer peaks between the ages of 55- 75. The overarching goal of this proposal is to identify the mechanism(s) whereby G334R is impaired for function. In a completely unexpected finding, we show that there are some activities of the G334R hypomorph that are shared with two other cancer-predisposing p53 hypomorphs, P47S and Y107H. These activities include a heightened propensity to misfold into a conformation that is specific for mutant p53, as well as increased sensitivity to glutaminase inhibitors. We also show that using RNA sequencing data and machine learning approaches, we have identified a 42-gene signature that is predictive of a p53 hypomorph, and can distinguish a p53 hypomorph from WT p53 or a benign variant with 100% accuracy. The proposed research will help us better understand tumor suppression by p53, and to identify other carriers of hypomorphic genetic variants of p53.

项目摘要 此提交代表了一个合作申请，从莫琳墨菲博士在Wistar研究所， Philadelphia和宾夕法尼亚大学佩雷尔曼医学院的Kara麦克斯韦医学博士/博士。 目的是研究一种新的p53突变的功能，这种突变首先在几种高度恶性肿瘤中发现， 在宾夕法尼亚大学医院的麦克斯韦医生的诊所里，这个变体， p53蛋白中的G334 R（小鼠p53中的G331 R）在9个不同的多发性癌症家族中被发现， 几代人，包括患有小儿肾上腺肿瘤的堂兄弟;后者是癌症的标志- 诱发TP 53突变。此外，我们发现这些患者的几个肿瘤显示出细胞凋亡的损失。 p53的杂合性。我们发现，G334 R变异体的寡聚化受损， 一小部分p53靶基因，其中几个本身就是肿瘤抑制基因（PCLO，PLXNB 3， 和其他）。 我们对G334 R变体的功能分析表明，这不是传统的Li Fraumeni突变体;也就是说， 一种完全使p53功能失活的突变相反，我们的功能数据与 G334 R是p53“低型”，或显示受损但不完全失活的遗传变体， 功能具体地，1）G334 R具有抑制肿瘤细胞中的集落形成的一些能力，尽管 G334 R反式激活绝大多数p53的能力较野生型弱; p53调节基因的表达，但在大约24个p53靶基因的反式激活中有缺陷; 3)G334 R个体中乳腺癌的发病率高峰在35-55岁之间，而大多数病例 的Li Fraumeni发生在20-40岁之间，散发性乳腺癌在55岁之间达到高峰， 75. 本提案的总体目标是确定G334 R功能受损的机制。 在一个完全出乎意料的发现中，我们表明G334 R亚型的一些活动是 与另外两种癌症易感性p53亚型P47 S和Y107 H共享。这些活动包括： 错误折叠成对突变型p53特异的构象的倾向增加， 对转氨酶抑制剂敏感。我们还表明，使用RNA测序数据和机器学习， 方法，我们已经确定了一个42个基因的签名，是预测p53亚型，并可以区分 来自WT p53的p53亚型或良性变异，准确率为100%。拟议中的研究将帮助我们 更好地了解p53的肿瘤抑制作用，并确定其他携带亚形态遗传变异的p53基因， 第53页。