Very long-chain acyl-CoA synthetase 3 mediates onco-sphingolipid metabolism in malignant glioma.
Very long-chain acyl-CoA synthetase 3 mediates onco-sphingolipid metabolism in malignant glioma.
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DOI：
10.18103/mra.v9i5.2433
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
E. Kolar;Xiaohai Shi;Emily M. Clay;A. Moser;B. Lal;R. Nirujogi;A. Pandey;V. Bandaru;J. Laterra;Z. Pei;P. Watkins
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作者：
E. Kolar;Xiaohai Shi;Emily M. Clay;A. Moser;B. Lal;R. Nirujogi;A. Pandey;V. Bandaru;J. Laterra;Z. Pei;P. Watkins
胶质瘤是成人原发性恶性脑肿瘤中最大的一类，其中胶质母细胞瘤占恶性胶质瘤的近一半。众所周知，胶质母细胞瘤具有侵袭性和耐药性，5 年生存率非常低，约为 5%。因此迫切需要新的治疗方法。我们之前发现一种脂肪酸代谢酶，即极长链酰基辅酶A合成酶3（ACSVL3），作为胶质母细胞瘤的潜在治疗靶点。使用胶质母细胞瘤细胞系 U87MG，我们创建了 ACSVL3 基因组缺失的细胞系 (U87-KO)，并研究了解释该酶如何支持胶质母细胞瘤细胞恶性特性的潜在机制。与U87MG细胞相比，U87-KO细胞生长较慢并且呈现出更正常的形态。他们在裸鼠身上产生了更少、更小的皮下异种移植物。酰基辅酶A合成酶，包括ACSVL3，将脂肪酸转化为其酰基辅酶A衍生物，从而参与多种下游脂质途径。我们研究了 ACSVL3 耗竭对几个此类途径的影响。 U87-KO 细胞中用于产生能量的脂肪酸降解不受影响。缺乏 ACSVL3 不会显着影响脂肪酸合成以及从头合成的脂肪酸与肿瘤细胞快速生长所需的膜磷脂的结合。相比之下，U87-KO 细胞表现出鞘脂代谢改变的证据。 U87-KO细胞中含有18-22碳脂肪酸的神经酰胺水平显着降低。这与 ACSVL3 的脂肪酸底物特异性谱相似。在 U87-KO 细胞中，硬脂酸（一种 18 碳饱和脂肪酸）掺入神经酰胺的速率降低，蛋白质组学显示神经酰胺合成途径酶的丰度较低。鞘脂，包括神经节苷脂，是脂筏的功能成分，脂筏是膜微域，被认为是受体介导的信号传导的组织中心。 ACSVL3 缺陷导致筏形态和神经节苷脂组成发生改变。最后，U87-KO 细胞中 1-磷酸鞘氨醇（一种鞘脂信号分子）的水平降低。我们得出结论，ACSVL3 至少部分通过改变细胞鞘脂代谢来支持 U87MG 细胞的恶性行为。
Gliomas are the largest category of primary malignant brain tumors in adults, and glioblastomas account for nearly half of malignant gliomas. Glioblastomas are notoriously aggressive and drug-resistant, with a very poor 5 year survival rate of about 5%. New approaches to treatment are thus urgently needed. We previously identified an enzyme of fatty acid metabolism, very long-chain acyl-CoA synthetase 3 (ACSVL3), as a potential therapeutic target in glioblastoma. Using the glioblastoma cell line U87MG, we created a cell line with genomic deletion of ACSVL3 (U87-KO) and investigated potential mechanisms to explain how this enzyme supports the malignant properties of glioblastoma cells. Compared to U87MG cells, U87-KO cells grew slower and assumed a more normal morphology. They produced fewer, and far smaller, subcutaneous xenografts in nude mice. Acyl-CoA synthetases, including ACSVL3, convert fatty acids to their acyl-CoA derivatives, allowing participation in diverse downstream lipid pathways. We examined the effect of ACSVL3 depletion on several such pathways. Fatty acid degradation for energy production was not affected in U87-KO cells. Fatty acid synthesis, and incorporation of de novo synthesized fatty acids into membrane phospholipids needed for rapid tumor cell growth, was not significantly affected by lack of ACSVL3. In contrast, U87-KO cells exhibited evidence of altered sphingolipid metabolism. Levels of ceramides containing 18-22 carbon fatty acids were significantly lower in U87-KO cells. This paralleled the fatty acid substrate specificity profile of ACSVL3. The rate of incorporation of stearate, an 18-carbon saturated fatty acid, into ceramides was reduced in U87-KO cells, and proteomics revealed lower abundance of ceramide synthesis pathway enzymes. Sphingolipids, including gangliosides, are functional constituents of lipid rafts, membrane microdomains thought to be organizing centers for receptor-mediated signaling. Both raft morphology and ganglioside composition were altered by deficiency of ACSVL3. Finally, levels of sphingosine-1-phosphate, a sphingolipid signaling molecule, were reduced in U87-KO cells. We conclude that ACSVL3 supports the malignant behavior of U87MG cells, at least in part, by altering cellular sphingolipid metabolism.