Project 1: Ionic Modulation of Chromatin in Cancer

摘要(项目1) 细胞内钾水平在调节生理过程中起着中心作用，通常 保持在狭窄的范围内。最近的研究表明，侵袭性和高转移性乳房以及 多发性骨髓瘤癌细胞维持的钾浓度比匹配的细胞高200-300% 非致瘤细胞。由于涉及可逆染色质的最强物理化学相互作用 凝聚是静电，原子核离子环境中的任何扰动，例如那些 通过细胞内钾含量的病理生理升高，预计将对 染色质结构和转录机制。因此，这一发现具有全球生理学意义 这意味着什么。它还有可能统一各种报告，表明升高的钾水平 抑制细胞死亡信号通路，以及作用于已知的大量离子通道蛋白 在癌症的发展中起着一定的作用。在这个提议中，我们检验了细胞内变化的假设 钾水平改变染色质结构和核组织，从而改变全球基因表达。 为了解决这一假设，我们将开发新的物理方法来：a)了解钾的影响 在肿瘤细胞的物理水平上集中在染色质结构上；b)探讨 升高的钾与人类肿瘤的临床分期和分级；以及c)检测癌细胞的这一方面 生理学可用于设计新的联合化疗药物。这些实验将是 跨越多个长度尺度：从完整的活细胞到孤立的核到中期染色体 最后是核小体核心颗粒。了解癌症中的离子失衡可能有助于重新调整用途 目前FDA批准的药物，如通过调节细胞内钾水平起作用的利尿剂，用于 与目前的化疗药物联合用于癌症治疗。药物组合将在 几种癌症，包括胶质母细胞瘤，通过与患者合作使用 Core的一系列分期和基因分型的GBM肿瘤株。该项目直接连接到拱顶 CR-PSOC“肿瘤中染色质的时空动力学和信息传递”框架 通过研究在癌症中起重要作用的核环境中的物理化学变化 进步。项目1研究人员将研究细胞内钾浓度的变化如何影响 染色质凝聚及其对恶性表型的影响。本组织的成员 跨学科团队将与项目3合作，以确定染色质压缩的程度 在完整的细胞核中，并与项目2的成员一起研究钾积累在 白血病。项目1在该中心的作用是解决癌细胞核的关键静电特征 然后应用新的见解来理解，并最终干预疾病的发展。

ABSTRACT (PROJECT 1) Intracellular potassium levels play a central role in regulating physiological processes and are generally maintained within narrow limits. Recent studies reveal that aggressive and highly metastatic breast as well as multiple myeloma cancer cells maintain potassium concentrations that are 200-300% higher than matched non-tumorigenic cells. Since the strongest physicochemical interactions involved in reversible chromatin condensation are electrostatic, any perturbations in the ionic environment of the nucleus, such as those driven by a pathophysiological elevation of cellular potassium content, are anticipated to have profound effects on chromatin structure and access to transcriptional machinery. Thus this discovery has global physiological implications. It also has the potential to unify a variety of reports showing that elevated potassium levels suppress cell death signaling pathways, as well as acting on the large number of ion channel proteins known to play a role in cancer progression. In this proposal we test the hypothesis that alterations in intracellular potassium levels alter chromatin structure and nuclear organization and consequently, global gene expression. To address this hypothesis we will develop new physical methods to: a) understand the impact of potassium concentration on chromatin structure at the physical level in tumor cells; b) probe the relationship between elevated potassium and clinical stage and grade of human tumors; and c) test whether this facet of cancer cell physiology can be exploited for the design of new combination chemotherapies. These experiments will be performed across multiple length scales: from intact living cells to isolated nuclei to metaphase chromosomes and finally on nucleosome core particles. Understanding ion imbalances in cancer may allow the repurposing of current FDA-approved agents, such as diuretics that work by modulating intracellular potassium levels, for use in combination with current chemotherapies for cancer treatment. Drug combinations will be tested in several cancers, including glioblastoma, through collaboration with the Patient Derived Xenograph Core using the Core's series of staged and genotyped GBM tumor lines. This project connects directly to the overarching framework of the CR-PSOC “Spatio-Temporal Dynamics of Chromatin and Information Transfer in Cancer” through the study of physiochemical changes in the nuclear environment that are important in cancer progression. Project 1 investigators will address how changes in cellular concentration of potassium impact chromatin condensation and how this contributes to the malignant phenotype. Members of this transdisciplinary team will work in collaboration with Project 3 to determine the extent of chromatin compaction in intact nuclei, and with members of Project 2 to examine the potential roles for potassium accumulation in leukemia. The role of Project 1 in the Center is to resolve key electrostatic features of the cancer cell nucleus and then apply the new insights to understand, and ultimately intervene in disease progression.