Determining the role of lipid droplets and their therapeutic potential in glioblastoma

确定脂滴在胶质母细胞瘤中的作用及其治疗潜力

基本信息

批准号：
10735417
负责人：
Deliang Guo
金额：
$ 55.86万
依托单位：
OHIO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-15 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10735417
关键词：
Adult Antioxidants Autophagocytosis Biology Brain Neoplasms Cell Death Cell Proliferation Cell membrane Cells Cellular Membrane Cellular Structures Cholesterol Cholesterol Esters Cholesterol Homeostasis Clinic Cystine Data Defense Mechanisms Diagnosis Drops Drug Metabolic Detoxication Enzymes Fatty Acids Funding Genes Glioblastoma Glucose Goals Growth Homeostasis Hydrolysis In Vitro Induction of Apoptosis Laboratories Lipids Malignant Neoplasms Measures Mediating Membrane Membrane Structure and Function Metabolism Mitochondria Names Oleic Acids Outcome Pathway interactions Play Pre-Clinical Model Primary Brain Neoplasms Prognosis Public Health Reactive Oxygen Species Regulation Resistance Resources Role Starvation Stearic Acids Stearoyl-CoA Desaturase Testing Therapeutic Tissues Toxic effect Translating Triglycerides Up-Regulation Xenograft Model cell growth cell injury cholesterol control combinatorial diacylglycerol O-acyltransferase effective therapy endoplasmic reticulum stress experimental study fatty acid oxidation in vivo inhibition of autophagy insight lipidomics neoplastic cell novel novel strategies oxidation pharmacologic pre-clinical prevent response synergism therapeutically effective tumor tumor growth uptake

项目摘要

ABSTRACT Over the past two decades, the prognosis for glioblastoma (GBM), the most lethal brain tumor, has remained dismal, with a median survival of only 12-16 months from diagnosis. We recently demonstrated that GBM cells acquire large amounts of fatty acids (FAs) and cholesterol by dramatically upregulating their de novo synthesis and uptake for rapid tumor growth. However, excess FAs and cholesterol can alter membrane dynamics and function, leading to cellular damage. How GBM cells avoid this lipotoxicity to sustain proper lipid levels in different cellular compartments, particularly in the mitochondria, is poorly understood. During the past 5 years of funding, we have made great progress in understanding how GBM controls FA homeostasis. We demonstrated that GBM cells upregulate diacylglycerol acyltransferase 1 (DGAT1), allowing them to store abundant FAs as triacylglycerol-containing lipid droplets (LDs) to prevent excess FA accumulation to induce toxicity. In this renewal proposal, we will address two unanswered critical questions: 1) how is cholesterol homeostasis regulated in GBM cells? and 2) can effective therapeutic approaches be developed for GBM by disrupting lipid homeostasis? We recently found that cholesteryl esters (CEs), which form LDs to store excess cellular cholesterol, are largely present in GBM tissues, and blocking CE synthesis results in dramatic mitochondrial fragmentation in GBM cells. Moreover, our preliminary data showed that cholesterol is transferred from CE- containing LDs (CE-LDs) to the plasma membrane, while inhibition of autophagy blocks this transfer. These data suggest that CE-LDs maintain proper cellular cholesterol levels via autophagy. Our preliminary data further showed that stearoyl-CoA desaturase 1 (SCD1), which has been shown to prevent endoplasmic reticulum (ER) stress and ferroptosis, is upregulated upon DGAT1 inhibition. Finally, preliminary data showed that the expression of multiple antioxidant genes is significantly elevated in response to DGAT1 inhibition. These results strongly suggest that GBM cells can activate defense mechanisms to alleviate the lipotoxicity triggered by disruption of FA storage, possibly leading to tumor resistance to DGAT1 inhibition. Thus, we hypothesize that CE-LDs serve as critical reservoirs for controlling cholesterol homeostasis and mitochondrial function, and that combining disruption of storage or redistribution of cholesterol with interference with mitochondrial cholesterol import, or disruption of FA storage with either inhibition of SCD1 or blockade of antioxidant pathways are effective strategies for targeting GBM. In Aim 1, we will examine the impact of inhibiting cholesterol storage or redistribution from CE-LDs on cholesterol homeostasis and mitochondrial function, and whether such blockade can synergize with interfering in cholesterol import into mitochondria to efficiently kill tumor cells in GBM xenograft models. In Aim 2, we will examine whether inhibiting SCD1 or antioxidant pathways can strongly synergize with DGAT1 inhibition to effectively inhibit GBM growth in vitro and in vivo. Successful completion of this study will provide strong pre-clinical data on potential novel strategies to target GBM.

抽象的在过去的二十年里，最致命的脑肿瘤——胶质母细胞瘤（GBM）的预后一直没有得到改善。令人沮丧的是，诊断后中位生存期仅为 12-16 个月。我们最近证明 GBM 细胞通过显着上调脂肪酸 (FA) 和胆固醇的从头合成来获取大量脂肪酸 (FA) 和胆固醇和摄取促进肿瘤快速生长。然而，过量的 FA 和胆固醇会改变膜动力学，功能，导致细胞损伤。 GBM 细胞如何避免这种脂毒性以在不同的环境中维持适当的脂质水平人们对细胞区室，特别是线粒体中的细胞区室知之甚少。在过去5年的资助中，我们在理解 GBM 如何控制 FA 稳态方面取得了很大进展。我们证明了 GBM 细胞上调二酰基甘油酰基转移酶 1 (DGAT1)，使它们能够储存丰富的 FA 含有三酰甘油的脂滴（LD）可防止过量的 FA 积累而引起毒性。在这个更新提案中，我们将解决两个悬而未决的关键问题：1）胆固醇稳态如何 GBM 细胞中受到调节？ 2) 能否通过破坏脂质来开发 GBM 的有效治疗方法体内平衡？我们最近发现胆固醇酯 (CE)，它形成 LD 来储存多余的细胞胆固醇，主要存在于 GBM 组织中，阻断 CE 合成会导致线粒体严重受损 GBM 细胞中的碎片化。此外，我们的初步数据表明，胆固醇是从CE-转移而来的。含有 LD (CE-LD) 到质膜，而抑制自噬会阻止这种转移。这些数据表明 CE-LD 通过自噬维持适当的细胞胆固醇水平。我们的初步数据进一步研究表明硬脂酰辅酶 A 去饱和酶 1 (SCD1) 可以预防内质网 (ER) 应激和铁死亡，在 DGAT1 抑制后上调。最后，初步数据显示，多种抗氧化基因的表达因 DGAT1 抑制而显着升高。这些结果强烈表明 GBM 细胞可以激活防御机制以减轻由 FA 储存的破坏，可能导致肿瘤对 DGAT1 抑制产生抵抗。因此，我们假设 CE-LD 作为控制胆固醇稳态和线粒体功能的关键储存库，将破坏胆固醇的储存或重新分配与干扰线粒体胆固醇相结合导入或通过抑制 SCD1 或阻断抗氧化途径来破坏 FA 储存是有效的针对 GBM 的策略。在目标 1 中，我们将研究抑制胆固醇储存或 CE-LDs 对胆固醇稳态和线粒体功能的重新分配，以及这种封锁是否可以协同干扰胆固醇进入线粒体，有效杀死 GBM 中的肿瘤细胞异种移植模型。在目标 2 中，我们将研究抑制 SCD1 或抗氧化途径是否可以强烈与 DGAT1 抑制协同作用，有效抑制体外和体内 GBM 生长。顺利完成这项研究将为针对 GBM 的潜在新策略提供强有力的临床前数据。