The pH-dependent adaptive advantage for recurrent histidine mutations in cancer

癌症中复发性组氨酸突变的 pH 依赖性适应性优势

基本信息

批准号：
8706661
负责人：
Katharine Alice White
金额：
$ 5.15万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-01 至 2016-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8706661
关键词：
Acute Myelocytic Leukemia Acute T Cell Leukemia Affinity Amino Acids Apoptosis Appearance Arginine Binding Biochemical Bioinformatics Cataloging Catalogs Cell Proliferation Cell physiology Cells Clonal Expansion Codon Nucleotides Complex Cosmic DNA Methyltransferase DNA Modification Methylases Databases Dependence Development Dimerization Disease Drug resistance Epidermal Growth Factor Receptor FBXW7 gene Frequencies Genetic Histidine Homodimerization Human Hydrogen Bonding Investigation Laboratories Link Malignant - descriptor Malignant Neoplasms Malignant neoplasm of lung Mesothelioma Metabolism Molecular Conformation Mutation Normal Cell Oncogenic Outcome Outcome Study Pathway interactions Phosphotransferases Process Proteins Recurrence Regulatory Pathway Relative (related person)Serine Site Somatic Mutation Source Survival Rate Testing Threonine Tissues Tumor Suppressor Proteins Tyrosine Ubiquitination Work cancer cell design enzyme activity extracellular fitness improved in vitro Assay insight molecular dynamics mutant novel therapeutic intervention pH gradient pressure programs public health relevance sensor success therapeutic target trait tumor progression ubiquitin ligase

项目摘要

DESCRIPTION (provided by applicant): Dysregulated pH is a hallmark of nearly all cancers regardless of tissue origin or genetic background. In normal cells, extracellular pH (pHe) is higher than intracellular pH (pHi) but in cancer cells this pH gradient is reversed. While the constitutive increase in pHi is small, it produces substantial changes in cell function. For example, the the increased pHi of cancer cells promotes cell proliferation and invasion while inhibiting apoptosis and altering cell metabolism. Here, we propose to investigate somatic mutations in cancer that may be conferring an increased fitness for the dysregulated pH of cancer. While somatic mutations in cancer are random, the increased pHi of cancers could provide a selective pressure for mutations that confer an adaptive advantage. Our hypothesis is that this selective pressure causes the conservation of histidine mutations in cancer that confer a gain in pH sensitivity. To investigate this hypothesis, in Aim 1 we will determine whether commonly occurring Arg>His mutations in candidate proteins confer a gain in pH-dependent function and what the mechanism of pH sensing might be. For each candidate we will test predictions that mutant but not wild- type proteins have pH-dependent functions by using biochemical assays in vitro and in cells. We also will test mechanisms of pH sensing of mutants by using molecular dynamics simulations and computational pKa predictions. In Aim 2 we will use database analyses to identify additional candidates with recurring histidine mutations, determine their frequency relative to codon bias frequency, and generate interaction networks to predict how these mutations might be conferring a functional adaptive advantage to cancer cells. These objectives will be achieved by using a database of amino acid mutations generated for the sponsor's laboratory from the Catalogue Of Somatic Mutations In Cancer (COSMIC) and established bioinformatics programs. To our knowledge this is the first examination of the adaptive retention and pH-dependent function of somatic mutations involving histidines in cancer. Our findings will generate new insights into how somatic mutations might be linked to the dysregulated pH in cancer. The results of this work might also reveal broad design principles of pH sensors that could inform the development of cancer therapeutics targeting pH-dependent pathways, regulatory mechanisms, or driver mutations.

描述（由申请人提供）：pH 失调是几乎所有癌症的标志，无论组织起源或遗传背景如何。在正常细胞中，细胞外 pH (pHe) 高于细胞内 pH (pHi)，但在癌细胞中，这种 pH 梯度相反。虽然 pHi 的持续增加很小，但它会导致细胞功能发生实质性变化。例如，癌细胞pHi升高会促进细胞增殖和侵袭，同时抑制细胞凋亡并改变细胞代谢。在这里，我们建议研究癌症中的体细胞突变，这些突变可能会增强癌症 pH 失调的适应性。虽然癌症中的体细胞突变是随机的，但癌症 pHi 的增加可能会为突变提供选择性压力，从而赋予适应性优势。我们的假设是，这种选择压力会导致癌症中组氨酸突变的保守，从而提高 pH 敏感性。为了研究这一假设，在目标 1 中，我们将确定候选蛋白质中常见的 Arg>His 突变是否会带来 pH 依赖性功能的增强，以及 pH 传感的机制可能是什么。对于每个候选蛋白，我们将通过体外和细胞内的生化测定来测试突变蛋白而非野生型蛋白具有 pH 依赖性功能的预测。我们还将通过分子动力学模拟和计算 pKa 预测来测试突变体的 pH 传感机制。在目标 2 中，我们将使用数据库分析来识别具有重复组氨酸突变的其他候选者，确定它们相对于密码子偏倚频率的频率，并生成相互作用网络来预测这些突变如何赋予癌细胞功能适应性优势。这些目标将通过使用从癌症体细胞突变目录（COSMIC）和已建立的生物信息学项目中为申办者实验室生成的氨基酸突变数据库来实现。据我们所知，这是对癌症中涉及组氨酸的体细胞突变的适应性保留和 pH 依赖性功能的首次检查。我们的研究结果将为体细胞突变如何与癌症中 pH 失调相关提供新的见解。这项工作的结果还可能揭示 pH 传感器的广泛设计原理，为针对 pH 依赖性途径、调节机制或驱动突变的癌症疗法的开发提供信息。