MODULATION OF IGF-II IMPRINTING IN THE AGING PROSTATE

老化前列腺中 IGF-II 印记的调节

• 批准号: 7077643
• 负责人: DAVID F. JARRARD
• 金额: $ 24.24万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7077643
• 关键词: DNA methylation; aging; cancer risk; cell senescence; diet; dietary aminoacid; disease /disorder etiology; flow cytometry; gene environment interaction; gene expression; genetic susceptibility; genomic imprinting; human tissue; insulinlike growth factor; laboratory mouse; laser capture microdissection; male; methionine; neoplasm /cancer genetics; nutrition aspect of cancer; nutrition related tag; patient oriented research; prostate; prostate neoplasms; tissue /cell culture

Three important features of prostate cancer will be addressed in the present proposal that will improve our understanding of risk factors for the development of prostate cancer. These features include: i) the multifocality of prostate cancer which implicates a generalized or field change in cancer susceptibility, ii) the age-dependence of prostate cancer development, and iii) the important role of the Insulin-like Growth Factor Axis in both aging-related and genetic-related cancers. IGF-II is an auto-paracrine growth stimulator that is an important positive modulator of cancer development. We provide preliminary evidence that a loss of imprinting (LOI), or biallelic expression, is an age-related specific epigenetic alteration that occurs in the peripheral prostate of the human. The imprinting of IGF-II in adult tissues is typically maintained and LOI is a common attribute of prostate cancers. Since DNA methylation is a major determinant of IGF-II imprinting we would anticipate that changes in methylation would be associated with altered imprinting status. It is our hypothesis to be tested that a loss of genomic imprinting in IGF-II is an age-related event in prostate epithelial cells and may be modulated by changes in DNA methylation. In Specific Aim 1, we will determine if a LOI of IGF-II occurs in the aging mouse prostate. In Specific Aim 2, the impact of accelerating DNA methylation loss on imprinting in mouse and an in vitro human model will be assessed. Specific Aim 3 will determine whether these mechanisms, and/or others, engender the increase in IGF-II expression seen in aging. This proposal is significant and novel in that it has the ability to provide a critical epigenetic link between the aging process, diet and prostate carcinogenesis in vivo. We expect to determine whether IGF-II imprinting is altered with aging and whether altered DNA methylation is an underlying mechanism for this. Even in the unlikely event the IGF-II plays only a minor role in prostate carcinogenesis, this proposal represents a novel and important methodological approach to evaluating epigenetic field changes that may explain the age-, organ- and diet-related specificity of prostate cancer.

本提案将讨论前列腺癌的三个重要特征，这将提高我们对前列腺癌发生的危险因素的理解。 这些特征包括：i) 前列腺癌的多灶性，这意味着癌症易感性的普遍或局部变化，ii) 前列腺癌发展的年龄依赖性，以及 iii) 胰岛素样生长因子轴在衰老过程中的重要作用相关和遗传相关的癌症。 IGF-II 是一种自动旁分泌生长刺激剂，是癌症发展的重要正调节剂。 我们提供的初步证据表明，印记丢失（LOI）或双等位基因表达是一种与年龄相关的特定表观遗传改变，发生在人类外周前列腺中。 IGF-II 在成人组织中的印记通常得以维持，而 LOI 是前列腺癌的一个常见属性。 由于 DNA 甲基化是 IGF-II 印记的主要决定因素，我们预计甲基化的变化将与印记状态的改变相关。 我们的假设是，IGF-II 基因组印记的丢失是前列腺上皮细胞中与年龄相关的事件，并且可能受到 DNA 甲基化变化的调节。 在具体目标 1 中，我们将确定衰老小鼠前列腺中是否发生 IGF-II 的 LOI。 在具体目标 2 中，将评估加速 DNA 甲基化丢失对小鼠和体外人类模型印记的影响。 具体目标 3 将确定这些机制和/或其他机制是否会导致衰老过程中 IGF-II 表达的增加。 该提议具有重要意义和新颖性，因为它能够在体内衰老过程、饮食和前列腺癌发生之间提供关键的表观遗传联系。 我们希望确定 IGF-II 印记是否会随着衰老而改变，以及 DNA 甲基化的改变是否是其潜在机制。 即使在不太可能发生的情况下，IGF-II 在前列腺癌发生中只发挥很小的作用，该提议代表了一种新颖且重要的方法来评估表观遗传领域的变化，这可能解释前列腺癌的年龄、器官和饮食相关的特异性。