Genomic Instability in Ageing and Cancer

衰老和癌症中的基因组不稳定性

• 批准号: 7798341
• 负责人: David J. Araten
• 金额: --
• 依托单位: VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7798341
• 关键词: Address; Age; Aging-Related Process; Antioxidants; Biological; Blood specimen; Caring; Cell Line; Cell division; Cells; Chemoprevention; Clinical Chemoprevention; DNA biosynthesis; Data; Dehydroascorbic Acid; Demographic Aging; Drug Delivery Systems; Elderly; Erythrocytes; Farnesyl Transferase Inhibitor; Flow Cytometry; Frequencies; Genes; Genomic Instability; Human; Incidence; Individual; Intervention; Investigation; Lamin Type A; Life; Link; Lymphoid Cell; Malignant Neoplasms; Measures; Membrane Proteins; Methods; Mutation; Neonatal; Normal Cell; Patients; Pharmaceutical Preparations; Phenotype; Population; Predisposition; Premature aging syndrome; Probability; Process; Progeria; Reactive Oxygen Species; Recruitment Activity; Screening procedure; Sentinel; Somatic Mutation; Syndrome; T-Lymphocyte; Umbilical Cord Blood; United States; Veterans; X Chromosome; age group; age related; base; cancer cell; cancer risk; cohort; granulocyte; high risk; lymphoblastoid cell line; mutant; older patient; prevent; public health relevance; trend; volunteer

DESCRIPTION (provided by applicant): Background: In humans, measuring the frequency (f) of cells harboring a mutation is possible for a very small number of sentinel genes and historically has been technically difficult. Measuring the mutation rate (<)--which represents the probability of new mutations occurring in a gene per cell division-- has been virtually impossible. Nevertheless, f and < may be key parameters in ageing. For example, it is hypothesized: (i) that < increases with age; (ii) that < is elevated in certain premature ageing syndromes; and (iii) that it might be possible to reduce ageing related cancers by decreasing <. We have now developed a robust method to measure these parameters using the PIG-A gene, which we hope will greatly facilitate the investigation of these hypotheses. PIG-A is on the X-chromosome- therefore a single inactivating mutation can produce the mutant phenotype. PIG-A mutants lack all GPI-linked membrane proteins, facilitating screening for rare cells with the GPI-null phenotype by flow cytometry. By this approach, we have been able to measure f in granulocytes, and both < and f in B lymphoblastoid cell lines and expanding cultures of ex vivo T lymphocytes from blood samples. Recently, we have shown that it is possible to measure f in human red cells in an additional sentinel gene, XK, which has similar advantages as PIG-A. Specific Aims (a): to determine whether < increases in humans as they age; (b): to determine whether it would be feasible to prevent ageing related cancers with pharmacologic agents that could decrease <. For aim (a), volunteer subjects in different age groups will be recruited, and < will be measured directly using PIG-A as a sentinel gene in B lymphoblastoid cell lines and T lymphocyte cultures, in comparison with neonatal cord blood samples. < will also be assessed indirectly, based on analysis of the frequency of granulocytes with PIG-A mutations and red cells with XK mutations as a function of age. For aim (b), using cells from normal older individuals and patients with progeria, the effect on the mutation rate will be determined for three pharmacologic approaches: quenching reactive oxygen species, modulating lamin A using farnesyltransferase inhibitors, and activating SIRT1. Preliminary data: < in cultures of lymphoid cells from normal individuals ranges from 3 to 53 x 10-7 mutations per cell division and is positively correlated with age. < is increased in cells from patients with cancer predisposition syndromes, premature ageing syndromes, and in malignant cell lines. A reduction in the spontaneous mutation rate in human cells has now been demonstrated using dehydroascorbic acid to reduce intracellular reactive oxygen species. Implications: Apart from addressing very important fundamental biological questions regarding ageing and cancer risk, studies under aim (a) are important for planning clinical chemoprevention studies. If < is constant throughout life, then any strategy to reduce mutations may need to start early. If however, as suspected, < starts to increase with age, it may be possible to prevent cancer by reducing < at a later age, once it starts to increase. Studies under aim (b) will be critical for predicting the optimal drug targets and pharmacologic strategy for reducing < clinically. PUBLIC HEALTH RELEVANCE: Narrative: The Department of Veterans' Affairs cares for a large cohort of elderly patients who are prone to cancer because they are elderly. A better understanding of the relationship between ageing and the mutation rate is very much needed to plan studies to prevent cancer in this population. The studies proposed here will help predict at what age intervention to decrease mutations might be required. These studies may also identify drugs that are likely to prevent mutations and cancer.

描述（由申请人提供）： 背景：在人类中，对于少数哨基因基因而言，可以测量具有突变的细胞的频率（F），并且从历史上讲，在技术上很困难。几乎不可能测量突变率（<） - 代表每个细胞分裂基因中发生的新突变的概率 - 几乎是不可能的。然而，F和<可能是衰老的关键参数。例如，它是假设的：（i）<随着年龄的增长而增加； （ii）在某些过早衰老综合征中<<升高； （iii）可以通过减少<<<。 现在，我们已经开发了一种强大的方法来使用PIG-A基因测量这些参数，我们希望这将极大地促进对这些假设的研究。 Pig-A在X染色体上 - 因此，单个灭活突变可以产生突变表型。 Pig-A突变体缺乏所有与GPI相关的膜蛋白，通过流式细胞仪促进稀有细胞对稀有细胞的筛查。通过这种方法，我们能够测量粒细胞中的F，以及B淋巴细胞细胞系中的<和F <和f，以及从血液样本的过体T淋巴细胞的培养物扩展。 最近，我们已经表明，可以在其他前哨基因XK中测量人类红细胞中的F，该基因具有与PIG-A相似的优势。特定目的（a）：确定<随着年龄的增长是否增加； （b）：确定可以防止与可能降低<<<<<<的药理剂相关的癌症的癌症是否可行。为了AIM（a），将招募不同年龄段的志愿者，并且将使用PIG-A直接测量B淋巴母细胞细胞系中的前哨基因和T淋巴细胞培养物。 <也将根据对猪A突变的粒细胞频率和带有XK突变随着年龄的函数的粒细胞的频率进行分析。对于AIM（B），使用来自正常老年人的细胞和患有后代患者的细胞，将确定三种药理方法对突变率的影响：淬灭活性氧，使用Farneylymyltransferase抑制剂调节层粘连蛋白A，并激活SIRT1。初步数据：<在正常个体的淋巴样细胞的培养物中，每个细胞分裂的3至53 x 10-7突变且与年龄呈正相关。 <来自癌症易感综合征，过早衰老综合征和恶性细胞系的细胞中的<增加。 现已证明，使用脱氢抗坏血酸来减少细胞内活性氧。 含义：除了解决有关衰老和癌症风险的非常重要的基本生物学问题外，目标（a）对于计划临床化学预防研究至关重要。如果<一生都是恒定的，那么任何减少突变的策略都可能需要尽早开始。但是，如有疑问，<随着年龄的增长开始增加，一旦开始增加，就有可能通过减少<后来的年龄来预防癌症。 AIM（B）下的研究对于预测最佳药物靶标和药物策略至关重要。 公共卫生相关性： 叙述：退伍军人事务部关心大量老年患者，他们容易患癌症，因为他们是老年人。对于计划研究以预防该人群的癌症，非常需要更好地了解衰老与突变率之间的关系。这里提出的研究将有助于预测可能需要降低突变的年龄干预。这些研究还可以鉴定出可能预防突变和癌症的药物。