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 这份投稿是维斯塔尔研究所莫琳·墨菲博士的一份合作申请 来自宾夕法尼亚大学佩雷尔曼医学院的医学博士卡拉·马克斯韦尔。 其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被发现-- 在宾夕法尼亚大学医院的麦克斯韦尔医生的诊所里，可以看到有倾向性的家庭。这个变种， P53蛋白中的G334R(小鼠P53中的G331R)在9个不同的家系中被发现 多代人，包括患有儿童肾上腺肿瘤的表亲；后者是癌症的标志- 易致突变的TP53基因。此外，我们发现这些患者的几个肿瘤显示出 P53基因杂合性。我们发现G334R变异体对齐聚作用和诱导作用均有损害 一小部分p53靶基因，其中几个本身就是肿瘤抑制基因(PCL0，PLXNB3， 和其他人)。 我们对G334R变异体的功能分析表明，这不是一个传统的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 G334R是一种P53“低畸型”，或一种表现为受损但不是完全不活跃的基因变体， 功能。具体地说，1)G334R具有一定的抑制肿瘤细胞集落形成的能力 2)G334R完全有能力反式激活绝大多数 在P53调控基因中，但在大约24个P53靶基因的反式激活中存在缺陷； 3)G334R人群的乳腺癌发病高峰年龄在35-55岁之间，而大多数病例 发生在20-40岁之间，零星的乳腺癌高峰期在55岁- 75. 这项建议的首要目标是确定G334R功能受损的机制(S)。 在一个完全出乎意料的发现中，我们发现G334R低晶型的一些活动是 与另外两个易癌的P53亚型P47S和Y107H相同。这些活动包括 错误折叠成突变型p53特有的构象的倾向增加，以及增加 对谷氨酰胺酶抑制剂的敏感性。我们还展示了使用RNA测序数据和机器学习 方法，我们已经确定了一个42基因标记，它可以预测P53低构型，并可以区分 WT P53的低畸型或良性变异体的准确率为100%。拟议的研究将对我们有所帮助 更好地了解P53对肿瘤的抑制作用，并识别其他亚型基因变异的携带者 P53。