DNA Methylation in Non-Hodgkin's Lymphomas

非霍奇金淋巴瘤中的 DNA 甲基化

• 批准号: 6862716
• 负责人: CHARLES W CALDWELL
• 金额: $ 25.81万
• 依托单位: UNIVERSITY OF MISSOURI-COLUMBIA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-16 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6862716
• 关键词: B lymphocyte; CpG islands; DNA methylation; cell differentiation; cell transformation; clinical research; data management; gene expression; gene induction /repression; genetic promoter element; genetic transcription; human tissue; imaging /visualization /scanning; immunomagnetic separation; microarray technology; neoplasm /cancer genetics; nonHodgkin' s lymphoma; nucleic acid sequence; oligonucleotides; polymerase chain reaction; technology /technique development

The major activity in our laboratory is studies of DNA methylation in tumorigenesis, a process commonly observed in GC-rich sequences called CpG islands in many types of human cancers and is often associated with transcriptional silencing. Using non-Hodgkin's lymphoma (NHL) as a model system, our discovery-driven preliminary studies demonstrate that DNA hypermethylation is not a random event; many CpG island loci are susceptible to methylation alteration. As a result of this epigenetic mutation, the expression of genes that govern key functions of the cell may become silent, leading to clonal proliferation of tumor cells. Differential susceptibility of critical CpG island loci to DNA hypermethylation may therefore influence the development of different NHL subtypes and may help explain differences in tumor growth and treatment outcomes. We have identified several loci that are differentially methylated and may be involved in lymphomagenesis. Our Central Hypothesis: B-cell differentiation is affected by methylation of CpG islands and this frequently leads to silencing of gene transcription. We further hypothesize that 1) Histological classes of NHL actually contain more than one clinical disease; 2) Hypermethylation of CpG island loci in NHL cells can generate unique molecular signatures that are associated with clinical subtypes and; 3) Dissecting these complex epigenetic profiles requires an understanding of gene methylation in normal, as well as neoplastic, B-cell differentiation. This application will expand a current version of our Methylation-Specific Oligonucleotide (MSO) microarray, an invention that combines the power of the bisulfite treatment protocol with the versatility of oligonucleotide microarrays, and apply this innovative technique to study DNA methylation in cases of B-cell NHL and normal B-cells at similar stages of differentiation, and relate these changes to gene silencing and classification. We plan to test our hypotheses by pursuing 4 specific aims; 1. Generate an MSO microarray for analysis of promoter hypermethylation at about 4,000 loci in 80 genes; 2. Determine patterns of CpG island methylation that characterize subsets of NHL classes and their putative normal stage of B-cell differentiation; 3. Correlate the status of promoter hypermethylation defined by MSO with gene expression; 4. Develop and apply data management, analysis and visualization tools to decipher methylation profiles of NHL classes. The proposed studies are expected to yield important insights into potential mechanisms of DNA methylation-driven gene silencing related to B-cell differentiation and development of clinical subtypes of NHL.

我们实验室的主要活动是研究肿瘤发生中的 DNA 甲基化，这是在许多类型的人类癌症中称为 CpG 岛的富含 GC 的序列中常见的过程，并且通常与转录沉默相关。我们以非霍奇金淋巴瘤 (NHL) 作为模型系统，以发现为驱动的初步研究表明，DNA 高甲基化不是一个随机事件；而是一个随机事件。许多 CpG 岛位点易受甲基化改变的影响。由于这种表观遗传突变，控制细胞关键功能的基因的表达可能会发生变化。 变得沉默，导致肿瘤细胞的克隆增殖。因此，关键 CpG 岛位点对 DNA 高甲基化的不同敏感性可能会影响不同 NHL 亚型的发展，并可能有助于解释肿瘤生长和治疗结果的差异。我们已经鉴定了几个差异甲基化的位点，并且可能与淋巴瘤发生有关。我们的中心假设：B 细胞分化受到 CpG 岛甲基化的影响，这经常导致基因转录沉默。我们进一步假设 1) NHL 的组织学分类实际上包含不止一种临床疾病； 2) NHL 细胞中 CpG 岛位点的高甲基化可以产生与临床亚型相关的独特分子特征； 3) 剖析这些复杂的表观遗传谱需要了解正常 B 细胞以及肿瘤 B 细胞中的基因甲基化 差异化。该应用将扩展我们当前版本的甲基化特异性寡核苷酸 (MSO) 微阵列，这项发明将亚硫酸氢盐治疗方案的强大功能与寡核苷酸微阵列的多功能性相结合，并应用这种创新技术来研究处于类似分化阶段的 B 细胞 NHL 和正常 B 细胞的 DNA 甲基化，并将这些变化与基因沉默和 分类。我们计划通过追求 4 个具体目标来检验我们的假设； 1. 生成MSO微阵列，用于分析80个基因的约4,000个位点的启动子高甲基化； 2. 确定表征 NHL 类别子集的 CpG 岛甲基化模式及其假定的 B 细胞分化正常阶段； 3. 将MSO定义的启动子高甲基化状态与基因表达相关联； 4. 开发并应用数据管理、分析和可视化工具来破译 NHL 类别的甲基化谱。拟议的研究有望对与 B 细胞相关的 DNA 甲基化驱动的基因沉默的潜在机制产生重要的见解 NHL临床亚型的分化和发展。