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.

项目概要 本提交内容代表了 Wistar 研究所 Maureen Murphy 博士的合作申请 Philadelphia 和 Kara Maxwell 是宾夕法尼亚大学佩雷​​尔曼医学院的医学博士/哲学博士。 我们的目标是研究一种新的 p53 突变的功能，这种突变首先在几种高度癌症中发现。 在宾夕法尼亚大学医院麦克斯韦医生的诊所就诊的易患病家庭。这个变体， p53 蛋白中的 G334R（小鼠 p53 中的 G331R）在患有多种癌症的 9 个不同家族中被发现 多代人，包括患有儿童肾上腺肿瘤的表兄弟姐妹；后者是癌症的标志—— TP53 的易感突变。此外，我们发现这些患者的一些肿瘤显示出 p53 的杂合性。我们表明 G334R 变体的寡聚化和诱导作用受到损害 p53 靶基因的一小部分子集，其中几个本身就是肿瘤抑制基因（PCLO、PLXNB3、 和其他）。 我们对 G334R 变体的功能分析表明，这不是传统的 Li Fraumeni 突变体；那是， 一种使 p53 功能完全失活的突变。相反，我们的功能数据与 G334R 是 p53 的“亚型”，或者是一种显示受损但并非完全失活的遗传变异体， 功能。具体来说，1) G334R 具有一定的抑制肿瘤细胞集落形成的能力，但 它显示出比野生型p53低的能力； 2) G334R完全有能力反式激活绝大多数 p53 调节基因，但在大约两打 p53 靶基因的反式激活方面存在缺陷； 3）G334R个体乳腺癌发病高峰年龄在35-55岁之间，而大多数病例 Li Fraumeni 的发病年龄在 20-40 岁之间，散发性乳腺癌的高峰期在 55-40 岁之间。 75. 该提案的总体目标是确定 G334R 功能受损的机制。 在一个完全出乎意料的发现中，我们表明 G334R 亚型的一些活性是 与另外两种易患癌症的 p53 亚型 P47S 和 Y107H 共有。这些活动包括 错误折叠成突变体 p53 特有构象的倾向增加，并且 对谷氨酰胺酶抑制剂的敏感性。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 基因特征，可以预测 p53 亚型，并且可以区分 来自 WT p53 的 p53 亚型或 100% 准确度的良性变体。拟议的研究将帮助我们 更好地了解 p53 的肿瘤抑制作用，并识别 p53 亚型遗传变异的其他携带者 第 53 页。