CpG island methylation discovery in prostate cancer

描述(申请人提供)：前列腺癌是美国男性第二大癌症相关死亡原因，绝大多数死亡原因是雄激素非依赖性和/或转移性疾病。虽然许多研究已经清楚地证明CpG岛高甲基化在前列腺癌中起着重要作用，就像在其他类型的癌症中一样，但缺乏识别CpG岛甲基化的新靶点的基因组扫描方法。基因组扫描方法已经在许多其他类型的癌症中显示了癌症类型特异性甲基化的变化，这表明可以在前列腺癌中获得类似的数据。此外，专门关注雄激素非依赖性和/或转移性前列腺癌的研究一直非常有限。在人类前列腺癌中解决这些问题有许多困难。因此，我们建议利用前列腺癌的TRAMP小鼠模型来确定CpG岛超甲基化的新靶点。我们将研究原发肿瘤、转移肿瘤和复发的雄激素非依赖性肿瘤，从而调查一组反映人类疾病的具有高度临床相关性的表型。我们将使用一种具有里程碑意义的限制性基因组扫描方法来识别小鼠模型中的新靶点。然后，我们将把在流浪鼠模型中的发现转化为人类疾病。为了实现这一点，我们将确定与小鼠基因组中确定的新靶点同源的人类基因组序列。然后，我们将使用一种高度敏感的新技术，Massarray定量甲基化分析(MA-QMA)，来确定在小鼠模型中发现的甲基化在人类前列腺癌中是否保守。该技术使用通常被克隆用于亚硫酸氢盐测序分析的PCR产物，而不是使用MALDI-TOF分析来定量确定PCR产物中每个CpG二核苷酸的甲基化数量。这项工作将有两个主要目的：第一，这将导致一组新的CpG岛在人类前列腺癌中变得超甲基化，并可能识别高级表型特有的事件；第二，这项工作将验证TRAMP小鼠模型作为进一步研究前列腺癌表观遗传学的有用工具。

DESCRIPTION (provided by applicant): Prostate cancer is the second leading cancer related cause of death in American men, with the vast majority of the mortality arising from the androgen independent and/or metastatic forms of the disease. Although many studies have clearly demonstrated that CpG island hypermethylation plays a significant role in prostate cancer, as in other types of cancer, genomic scanning approaches to identify novel targets of CpG island methylation have been lacking. Genomic scanning approaches have demonstrated cancer type specific methylation changes in many other types of cancers suggesting that similar data could be obtained for prostate cancer. Furthermore, studies focusing specifically on the androgen independent and/or metastatic forms of prostate cancer have been very limited. Addressing these questions in human prostate cancer is confounded by a number of difficulties. We therefore propose to take advantage of the TRAMP mouse model of prostate cancer to identify novel targets of CpG island hypermethylation. We will study primary tumors, metastatic tumors, and recurrent androgen independent tumors, thus surveying a set of phenotypes reflective of the human disease that have high clinical relevance. We will use a restriction landmark genomic scanning approach to identify novel targets in the mouse model. We will then translate the discoveries made in the TRAMP mouse model to the human disease. To accomplish this, we will identify human genomic sequences that are orthologous to the novel targets identified in the mouse genome. We will then use a highly sensitive novel technology, MassArray Quantitative Methylation Analysis (MA-QMA), to determine if the methylation found in the mouse model is conserved in human prostate cancer. This technique uses PCR products that would normally be cloned for bisulfite sequencing analysis and instead uses MALDI-TOF analysis to quantitatively determine the amount of methylation at each CpG dinucleotide within the PCR product. This work will serve 2 major purposes: 1st, this will lead to the identification of a novel set of CpG islands that become hypermethylated in human prostate cancer and may identify events specific for advanced phenotypes; 2nd this work will serve to validate the TRAMP mouse model as a useful tool for further research into the epigenetics of prostate cancer.