Epigenomic Mapping in Human Tumor Stem Cells

肿瘤干细胞的概念，一种能够再生肿瘤的自我更新细胞， 揭示了人类癌症的持久性，并为翻译提供了一个新的焦点 研究。我们的目标是了解区分肿瘤干细胞的表观遗传学机制。 来自肿瘤其他细胞和其他正常的、自我更新的细胞。表观遗传 染色质修饰、DNA甲基化和小的非编码RNA等机制是 细胞转录潜能的稳定、长期(通常是可遗传的)变化 与潜在基因组序列的变化无关。细胞的表观遗传状态 用来定义细胞身份和该细胞的界限？S潜在的命运。因此，了解 细胞的表观遗传状态可以识别肿瘤干细胞的特性和潜能。 组蛋白修饰、DNA甲基化和小非编码的表观遗传状态 将使用染色质免疫沉淀、亚硫酸氢盐转化和生成来映射RNA RNA文库与全基因组测序相结合。为了深入了解肿瘤干细胞，我们将 利用以前开发的模型系统，该模型系统提供一致的 具有肿瘤干细胞能力的细胞。拟议中的实验将检验 一组细胞，每个细胞被分选为具有肿瘤干细胞能力的亚群。为 比较而言，非肿瘤干细胞的分离来源将是相同和不同的 将研究肿瘤干细胞与多能和多能干细胞之间的关系。 将设计更多的实验来干扰细胞的表观基因组，并直接测试如何 来源细胞的表观遗传状态影响随后的肿瘤表型。 所产生的知识可能会带来实质性的新见解，包括 确定早期诊断、预后或监测肿瘤治疗的可能标记物。 了解肿瘤干细胞和其他自我更新细胞之间的差异可能 导致更具体的治疗，对正常细胞的毒性也较低。操纵 表观基因组状态和检查致瘤性的结果将提供对 这些特征如何转化为临床相关的表型。

The concept of a tumor stem cell, a self-renewing cell capable of regenerating the tumor, has shed light on the persistence of human cancers and offers a new focus for translational research. Our goal is to understand the epigenetic mechanisms that distinguish the tumor stem cell from other cells of the tumor and from other normal, self-renewing cells. Epigenetic mechanisms, such as chromatin modifications, DNA methylation and small noncoding RNAs are stable, long-term (typically heritable) changes in the transcriptional potential of a cell that are independent of changes in the underlying genomic sequence. The epigenetic state of a cell serves to define cell identity and the limits of that cell¿s potential fates. Thus, knowledge of the epigenetic state of cells may identify signature for both tumor stem cell identity and potential. The epigenetic states of histone modifications, DNA methylation and small noncoding RNAs will be mapped using chromatin immunoprecipitation, bisulfite conversion and generation of RNA libraries coupled with genome-wide sequencing. For insight on tumor stem cells, we will take advantage of a previously developed model system that provides a consistent source of cells with tumor stem cell ability. Proposed experiments will examine the differences between a panel of cells, each sorted to enrich for the subpopulation with tumor stem cell ability. For comparisons, non-tumor stem cells will be isolated from the same source and the differences between tumor stem cells and pluripotent and multipotent stem cells will be examined. Additional experiments will be designed to perturb the epigenome of cells and directly test how the epigenetic state of the cell-of-origin affects subsequent tumor phenotype. The knowledge generated could lead to substantial new insights, including the identification of putative markers for early diagnosis, prognosis or monitoring of tumor therapies. Understanding the differences between tumor stem cells and other self-renewing cells could lead to more specific therapies that were also less toxic to normal cells. Manipulating the epigenomic state and examining the results on tumorigenicity would provide direct insight on how these signatures translate into clinically relevant phenotypes.