The role of chromatin regulation in normal and cancer stem cell self-renawal

描述（由申请人提供）：干细胞（正常和癌细胞）的定义是它们自我更新的能力，以维持它们的数量，以及它们分化成不同细胞类型的能力。由于这些相互竞争的功能，干细胞的基因组必须有独特的调控——干细胞在自我更新过程中必须稳定地维持其基因表达模式，但在分化过程中必须足够灵活，以彻底改变其基因表达模式。干细胞的基因表达模式受细胞内表达的转录因子和染色质调节因子的调控。虽然控制干细胞自我更新的转录因子在不同类型的干细胞之间差异很大，但越来越多的证据表明，染色质调节自我更新的功能更为广泛。最近，我对胚胎干细胞中具有重要功能的染色质调节因子进行了RNAi筛选，发现了68个具有一系列敲低表型的基因。现在我将筛选这些因子在另一种干细胞类型，癌症干细胞中的功能。使用小鼠模型和人类癌细胞系，我将确定癌症干细胞的染色质调节因子，目的是确定针对癌症干细胞的更有效治疗的新靶点。此外，我将研究在胚胎干细胞筛选中发现的一组染色质调节因子的干细胞特异性功能，即凝缩蛋白复合物。虽然凝缩蛋白在所有细胞类型中都有已知的功能，但胚胎干细胞对凝缩蛋白的丢失非常敏感。初步数据表明，这些因子具有干细胞独有的未知功能。现在我来描述一下这些函数。最后，我将使用我开发的在胚胎干细胞中敲除染色质调节因子的方法来检查转录因子和染色质调节因子的功能相互作用。在导师阶段，我将进行癌症干细胞中染色质重塑者的筛选，这将产生许多研究途径，将在独立阶段进行。此外，我将学习新的技术，并参与职业发展计划，这将有助于我成为一名独立的科学家，并在学术研究机构获得独立的职位。

DESCRIPTION (provided by applicant): Stem cells (both normal and cancerous) are defined by their ability to self-renew, in order to maintain their numbers, and their ability to differentiate into distinct cell types. Because of these competing functions, the genome of stem cells must be uniquely regulated-stem cells must stably maintain their gene expression pattern during self-renewal, but must be flexible enough to drastically alter their gene expression pattern during differentiation. The gene expression patterns of stem cells are regulated by transcription factors and chromatin regulators expressed in the cell. While transcription factors that control stem cell self-renewal vary considerably between different types of stem cells, there is increasing evidence that chromatin regulators of self-renewal function more broadly. Recently I performed an RNAi screen for chromatin regulators with important functions in embryonic stem cells and found 68 genes with an array of knockdown phenotypes. I will now screen these factors for function in a different stem cell type, cancer stem cells. Using both mouse models and human cancer cell lines, I will identify chromatin regulators of cancer stem cells, with the goal of identifying novel targets for more effective therapies that target the cancer stem cells. In addition, I will examine the stem cell-specific functions of one group of chromatin regulators identified in the embryonic stem cell screen, the condensin complexes. While condensins have known functions in all cell types, embryonic stem cells are acutely sensitive to their loss. Preliminary data indicates that these factors have previously unknown functions unique to stem cells. I will now characterize these functions. Finally, I will use methodology I developed for knocking down chromatin regulators in embryonic stem cells to examine the functional interactions of transcription factors and chromatin regulators. During the mentored phase of the award, I will carry out the screen of chromatin remodelers in cancer stem cells, which will generate many avenues of research that will be pursued during the independent phase. In addition, I will learn new techniques and participate in career development programs that will assist me in becoming an independent scientist and obtaining an independent position at an academic research institution. RELEVANCE: While normal stem cells hold promise for the development of therapies for regenerative diseases, cancer stem cells present a difficult challenge for traditional cancer therapies. Therefore, an understanding of how stem cells (normal and cancerous) maintain their identity would be beneficial for both regenerative medicine and identification of new therapies. Here I will examine how different stem cells are maintained.