Molecular Etiology of Enchondromatosis

内生软骨瘤病的分子病因学

• 批准号: 10431777
• 负责人: Benjamin Aaron Alman
• 金额: $ 40.37万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-23 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10431777
• 关键词: Animals; Benign; Binding Proteins; Binding Sites; Bone neoplasms; Cell Energetics; Cell Maintenance; Cell Survival; Cell physiology; Cells; Cholesterol; Chondrocytes; Chondrogenic Neoplasm; Chondroma; Chondrosarcoma; Citric Acid Cycle; Clinical; Clinical Data; Data; Deformity; Development; Enchondromatosis; Energy-Generating Resources; Enzymes; Epigenetic Process; Epiphysial cartilage; Etiology; Foundations; GYS1 gene; Genes; Genetic Transcription; Glycogen; Glycogen (Starch) Synthase; Glycogenolysis Inhibition; Growth; Human; Human Cell Line; Hyperactivity; In Vitro; Isocitrate Dehydrogenase; Isocitrates; Knockout Mice; Lead; Maintenance; Malignant - descriptor; Mediating; Mediator of activation protein; Metabolic; Metabolism; Metatarsal bone structure; Molecular; Mus; Mutant Strains Mice; Mutation; Neoplasms; Pain; Pathological fracture; Pathology; Patient-Focused Outcomes; Pharmaceutical Preparations; Pharmacology; Phenotype; Play; Population; Process; Production; Proliferating; Promoter Regions; Protein phosphatase; Proteins; Regulation; Regulatory Element; Role; Signal Pathway; Somatic Mutation; Source; Sterols; Testing; Transcriptional Activation; Tumor Cell Line; Work; Xenograft procedure; alpha ketoglutarate; base; bone; cartilage development; cartilaginous; cell growth; cholesterol biosynthesis; conditional knockout; effective therapy; glycogenolysis; improved; inhibitor; mutant; neoplastic; neoplastic cell; novel; novel therapeutics; overexpression; pre-clinical; prevent; skeletal; targeted agent; tumor; tumor growth; tumor initiation

Abstract More than 3% of the population develops an enchondroma (ECA), a benign tumor in bone composed of cells derived from the growth plate that can cause pain, deformity, and can be responsible for pathologic fractures. Enchondromas can progress to malignant chondrosarcoma (CSA). Mutations in genes encoding isocitrate dehydrogenase (IDH1 and 2) were identified in a large proportion of ECAs and CSAs. In our prior work, we found that IDH mutations inhibit growth plate chondrocyte differentiation, and chondrocyte-specific conditional Idh1 mutant mice develop ECAs. Mutant IDH uniquely produces the metabolite 2-hydroxyglutarate (2-HG), but we and others found that blocking the production of 2-HG pharmacologically does not alter CSA cell viability. While 2-HG has epigenetic effects that are likely important in tumor initiation, tumor maintenance must rely on other factors. Since IDH plays an important role in in metabolism, associated metabolic changes could drive the observed phenotype. We found high levels of glycogen in cells expressing a mutant IDH. Glycogen is also found in proliferating and pre-hypertrophic cells of the growth plate. In our previous work, we found that intracellular cholesterol biosynthesis was activated in IDH mutant chondrocytes and that it is also regulated in the growth plate, and its activity corelates with glycogen levels. This raises the possibility that intracellular cholesterol biosynthesis, which is activated by Sterol regulatory-element binding proteins (SREBP) transcription, also regulates glycogen. Our premise is that glycogen is an important energy source for pre- hypertrophic and hypertrophic growth plate chondrocytes and that glycogen stores are required to maintain the neoplastic phenotype in ECA and CSA. We also propose that glycogen depletion can suppress the neoplastic phenotype. In this proposal we will study what regulates glycogen in the growth plate, ECA and CSA, and determine the function of glycogen in these growth plate and neoplastic chondrocytes. To determine what regulates glycogen in the growth plate, ECA, and CSA, we prioritized genes known to regulate glycogen that were differentially regulated in the growth plate and by IDH mutations. Protein phosphatase 1 regulatory subunit 3C (PPP1R3C) is one such gene which is differentially and interestingly, contains SREBP binding sites in its promoter region. Our preliminary data suggest that SREBP regulates PPP1R3C which then regulates glycogen. Our studies will use cell lines from human tumors and genetically modified mice that develop enchondromas to define the function of glycogen and PPP1R3C in the growth plate, ECA, and CSA. In addition, we will study how SREBP regulates PPP1R3C and glycogen. Glycogen synthase will be deleted genetically, or we will cells with drugs that inhibit glycogen synthesis and breakdown. This data will provide pre-clinical information on which to base novel therapies for ECA and CSA.

抽象的 超过 3% 的人口患有内生软骨瘤 (ECA)，这是一种由细胞组成的骨良性肿瘤 源自生长板，可引起疼痛、畸形，并可能导致病理性骨折。 内生软骨瘤可进展为恶性软骨肉瘤（CSA）。编码异柠檬酸的基因突变 在大部分 ECA 和 CSA 中发现了脱氢酶（IDH1 和 2）。在我们之前的工作中，我们 发现 IDH 突变抑制生长板软骨细胞分化，并且软骨细胞特异性条件 Idh1 突变小鼠产生 ECA。突变体 IDH 独特地产生代谢物 2-羟基戊二酸 (2-HG)，但是 我们和其他人发现，从药理学上阻断 2-HG 的产生不会改变 CSA 细胞的活力。 虽然 2-HG 具有表观遗传效应，这可能对肿瘤的发生很重要，但肿瘤的维持必须依赖于 其他因素。由于 IDH 在新陈代谢中发挥着重要作用，相关的代谢变化可能会驱动 观察到的表型。我们在表达突变 IDH 的细胞中发现了高水平的糖原。糖原也是 存在于生长板的增殖和肥大前细胞中。在我们之前的工作中，我们发现 IDH 突变软骨细胞中的细胞内胆固醇生物合成被激活，并且在 生长板，其活性与糖原水平相关。这增加了细胞内 胆固醇生物合成，由甾醇调节元件结合蛋白 (SREBP) 激活 转录，也调节糖原。我们的前提是糖原是预产期的重要能量来源 肥大和肥大生长板软骨细胞，并且需要糖原储存来维持 ECA 和 CSA 的肿瘤表型。我们还提出糖原消耗可以抑制肿瘤的发生 表型。在本提案中，我们将研究生长板、ECA 和 CSA 中糖原的调节因素，以及 确定这些生长板和肿瘤软骨细胞中糖原的功能。 为了确定生长板、ECA 和 CSA 中糖原的调节因素，我们优先考虑了已知的基因 调节生长板中和 IDH 突变差异调节的糖原。蛋白质 磷酸酶 1 调节亚基 3C (PPP1R3C) 就是这样一种基因，它具有差异性且有趣的是， 其启动子区域含有 SREBP 结合位点。我们的初步数据表明 SREBP 调节 PPP1R3C 随后调节糖原。我们的研究将使用来自人类肿瘤和基因的细胞系 对发育内生软骨瘤的小鼠进行改良，以确定糖原和 PPP1R3C 在生长中的功能 板、ECA 和 CSA。此外，我们还将研究SREBP如何调节PPP1R3C和糖原。糖原 合酶将被基因删除，或者我们将用抑制糖原合成和分解的药物来细胞。 这些数据将提供临床前信息，为 ECA 和 CSA 的新疗法奠定基础。