Acyl-CoA synthetase ACSVL3 in Malignant Glioma: Metabolism and Oncogenic Cellular

恶性胶质瘤中的酰基辅酶 A 合成酶 ACSVL3：代谢和致癌细胞

• 批准号: 7736241
• 负责人: Paul A. WATKINS
• 金额: $ 35.22万
• 依托单位: HUGO W. MOSER RES INST KENNEDY KRIEGER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7736241
• 关键词: 1,2-diacylglycerol; Accounting; Adult; Affect; Apoptosis; Appearance; Autophagocytosis; Behavior; Brain Neoplasms; Cell Line; Cell Proliferation; Cells; Cellular Membrane; Childhood; Coenzyme A; Coenzyme A Ligases; Data; Diglycerides; Environment; Enzymes; Event; Family; Family member; Fatty Acids; Glioma; Growth; Histologic; Human; In Vitro; Knowledge; Lipids; Malignant - descriptor; Malignant Glioma; Mediating; Membrane; Membrane Lipids; Metabolic; Metabolic Pathway; Metabolism; Modeling; Mus; Neuroglia; Oncogenic; PTEN gene; Pathway interactions; Phenotype; Phosphatidylinositols; Phospholipase; Phospholipase C; Phosphorylation; Phosphotransferases; Population; Pre-Clinical Model; Proteins; RNA Interference; Reaction; Receptor Protein-Tyrosine Kinases; Refractory; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Signaling Molecule; Signaling Protein; Specificity; Structure; Therapeutic; Translating; Tumor Suppressor Proteins; Tumorigenicity; Up-Regulation; Work; Xenograft Model; Xenograft procedure; base; cancer cell; cell growth regulation; fatty acid metabolism; glioma cell line; in vivo; knock-down; lipid metabolism; malignant phenotype; novel; novel therapeutic intervention; overexpression; public health relevance; rapid growth; research study; second messenger; subcutaneous; therapeutic target; tumor; tumor growth; tumorigenesis

DESCRIPTION (provided by applicant): Malignant glioma accounts for a significant percentage of brain tumors. As these tumors are typically refractory to treatment, there is a need for new and novel therapeutic approaches. Levels of ACSVL3, an enzyme of fatty acid (FA) metabolism, were found to be highly upregulated in human malignant gliomas and were induced by oncogenic receptor tyrosine kinase (RTK) signaling in cultured glioma cells. ACSVL3 is one of 26 acyl-CoA synthetases (ACS) that "activate" FAs for their participation in biosynthetic, degradative, and regulatory downstream metabolic pathways. Rapid tumor growth requires high rates of membrane lipid synthesis; these lipids also have key functions in oncogenic cytoplasmic signaling. Using a well-established preclinical model of human glioma, we found that ACSVL3 knockdown (KD) using RNA interference decreased the in vitro malignant phenotype of human glioma cells. We established a correlation between ACSVL3 expression and tumorigenesis in glioma xenografts in vivo. We further established a relationship between ACSVL3 expression and oncogenic second messenger signaling via the phosphatidyl inositol-3 kinase (PI3K)/Akt and phospholipase c-3 (PLC-3)/diacylglycerol (DAG) pathways. We hypothesize that ACSVL3 generates specific FA-CoA products that influence oncogenesis by (i) generating specific structural lipids (ii) altering lipids involved directly in cell signaling, or (iii) altering lipids involved in membrane interactions with specific oncogenic signaling proteins. Based on our preliminary findings, we also hypothesize that targeting ACSVL3 will be of therapeutic value in treating malignant glioma, and propose the following Specific Aims: (1) To identify the consequences of ACSVL3 depletion on the in vitro phenotype of human glioma cell lines, (2) To identify the consequences of ACSVL3 depletion on lipid metabolism in malignant glioma cells, (3) To elucidate how ACSVL3 KD alters signal transduction in malignant glioma cells, and (4) To determine how ACSVL3 depletion inhibits glioma tumorigenicity. In Aim 1 we will investigate cell proliferation, apoptosis, and autophagy in control and KD human glioma cells to determine the specificity for ACSVL3 in oncogenesis. These studies will also be extended to other glioma models that may prove useful in subsequent Aims, such as cell lines that endogenously express the tumor suppressor PTEN. The function of ACSVL3 in lipid metabolism is not known for either normal or cancer cells. Aim 2 proposes studies to fill this gap in knowledge that will also identify lipid pathways that correlate with the malignant phenotype. In Aim 3, detailed analyses of the PI3K/Akt and PLC-?/ DAG signaling pathways in control and ACSVL3 KD glioma cells will be carried out. In Aim 4, effects of ACSVL3 KD on in vivo tumorigenesis, alterations in lipid metabolism, and RTK signaling will be explored, both in subcutaneous and in intracranial xenografts. The results of these studies will establish the mechanistic basis for ACSVL3 upregulation in glioma, pinpoint the role of this enzyme in oncogenic RTK signaling and lipid metabolism, and validate the therapeutic potential of targeting this protein in malignant glioma. PUBLIC HEALTH RELEVANCE: Malignant glioma accounts for a significant percentage of brain tumors in both the pediatric and adult populations, and there is a need for new and novel therapeutic approaches. In this application we will investigate an enzyme of fatty acid metabolism that we have identified as uniquely upregulated in human malignant glioma. Results of these studies will provide a critical assessment of the mechanism by which this enzyme contributes to the malignant phenotype, and the potential therapeutic benefit of targeting this enzyme in glioma.

描述（申请人提供）：恶性胶质瘤在脑肿瘤中占很大比例。由于这些肿瘤通常难以治疗，因此需要新的治疗方法。ACSVL3是一种脂肪酸（FA）代谢酶，在人类恶性胶质瘤中被发现高度上调，并在培养的胶质瘤细胞中被致癌受体酪氨酸激酶（RTK）信号诱导。ACSVL3是26种酰基辅酶a合成酶（ACS）中的一种，可以“激活”FAs参与生物合成、降解和调节下游代谢途径。肿瘤的快速生长需要高速率的膜脂合成；这些脂质在致癌细胞质信号传导中也有关键作用。通过建立成熟的人类胶质瘤临床前模型，我们发现使用RNA干扰敲低ACSVL3 （KD）可降低人类胶质瘤细胞的体外恶性表型。我们在体内建立了ACSVL3表达与异种胶质瘤发生之间的关系。我们进一步通过磷脂酰肌醇-3激酶(PI3K)/Akt和磷脂酶c-3 (PLC-3)/二酰基甘油（DAG）途径建立了ACSVL3表达与致癌第二信使信号传导之间的关系。我们假设ACSVL3产生特异性FA-CoA产物，通过(i)产生特异性结构脂质（ii）改变直接参与细胞信号传导的脂质，或（iii）改变参与与特异性致癌信号蛋白膜相互作用的脂质来影响肿瘤的发生。根据我们的初步研究结果，我们也假设靶向ACSVL3在治疗恶性胶质瘤中具有治疗价值，并提出以下具体目的：(1)确定ACSVL3缺失对人胶质瘤细胞系体外表型的影响；(2)确定ACSVL3缺失对恶性胶质瘤细胞脂质代谢的影响；(3)阐明ACSVL3 KD如何改变恶性胶质瘤细胞的信号转导；(4)确定ACSVL3缺失如何抑制胶质瘤的致瘤性。在目的1中，我们将研究对照和KD人类胶质瘤细胞的细胞增殖、凋亡和自噬，以确定ACSVL3在肿瘤发生中的特异性。这些研究还将扩展到其他胶质瘤模型，这些模型可能在随后的目标中证明是有用的，例如内源性表达肿瘤抑制因子PTEN的细胞系。ACSVL3在正常细胞和癌细胞的脂质代谢中的功能尚不清楚。目的2提出了填补这一知识空白的研究，也将确定与恶性表型相关的脂质途径。在Aim 3中，详细分析了PI3K/Akt和PLC-？/ DAG信号通路在对照和ACSVL3 KD胶质瘤细胞中进行。在Aim 4中，将探讨ACSVL3 KD对皮下和颅内异种移植物体内肿瘤发生、脂质代谢改变和RTK信号传导的影响。这些研究结果将建立ACSVL3在胶质瘤中上调的机制基础，明确该酶在致癌RTK信号和脂质代谢中的作用，并验证靶向该蛋白在恶性胶质瘤中的治疗潜力。