糖酵解/脂肪酸β氧化代谢模式转变驱动恶性胶质母细胞瘤的分化及其表观遗传学机制研究

Cancer cells is characterized by Warburg effect which strongly surpports the rapid growth. We found that anti-Warburg effect by cAMP signal agonists induces glioblastoma (GBM) cell differentiation into mature cells, which provide pivotal evidences for differentiation-inducing therapy of solid tumor (Cell Reports，2017). Based on the research above, we screened 349 chemicals and identified a high-efficient combination regimen. Then through a high-throughout acetylation analysis, metabolic enzymes in glycolysis have been found to be increasingly acetylated, while ones in fatty acid oxidation (FAO) have been found to be decreasingly acetylated. In another word, chemical induced GBM cells go through a glycolysis/FAO switch. In addition, we observed enhanced acetylation levels of histone 3 lysine 9 and lysine 14 (H3K9/K14), coordiratedly regulating expression of differentiation related genes. Therefore, it’s an extremely meaningful scientific question that the glycolysis/FAO switch drives the neuron induction of GBM cells. In this project, we will reveal the mechanism underlying the neuron induction and confirm the role of Ac-CoA derived from FAO in histone acetylation. If this project is successfully fulfilled, we will originally prove that the switch of entity/energy metabolic model controls the transformation of GBM cells from malignant phenotype to mature one, and will provide a novel strategy for differentiation-inducing therapy of GBM.

沃伯格效应是恶性肿瘤维持快速生长的特征性代谢模式。申请者发现，逆转沃伯格效应可诱导恶性胶质母细胞瘤（GBM）的分化，为实体瘤的诱导分化提供了重要依据（Cell Reports，2017）。在此基础上，申请者筛选349个化合物，获得了高效的联合诱导方案；乙酰化组学分析发现，分化后GBM细胞发生了糖酵解/脂肪酸β氧化代谢酶的乙酰化反转性重构，造成线粒体代谢从糖依赖转变为脂肪酸依赖；分化后的GBM细胞发生组蛋白H3K9和K14的乙酰化显著增强，协同调控了分化相关基因的表达。因而，糖酵解/脂肪酸β氧化代谢转变介导GBM细胞分化的机制成为一个极具意义的科学问题。本项目拟进一步确证，激活的脂肪酸氧化促进Ac-CoA的产生和组蛋白乙酰化，进而引起分化基因表达和GBM细胞分化。本项目的完成，将原创性地证明GBM细胞物质/能量代谢模式转变驱动恶性表型向良性表型的转变，为GBM的诱导分化疗法提供靶向新策略。

课题前期工作发现在8-CPT-cAMP和MS-275（CM组合）诱导恶性胶质瘤（GBM）细胞分化，引起组蛋白乙酰化重构和糖代谢/脂肪酸氧化代谢关键酶乙酰化重构。基于以上基础，本项目应用中链脂肪酸辛酸处理GBM，辛酸模拟了CM对组蛋白的重构作用和对分化的诱导作用；同时发现组蛋白关键位点H3H9/K14/K27的乙酰化共同调控了分化相关基因、细胞周期和肿瘤相关通路的变化，有利于GBM细胞发生分化表型改变。分子机制上，我们发现辛酸介导的组蛋白乙酰化依赖于柠檬酸裂合酶（ACLY）而不是乙酰辅酶A合成酶（ACSS2）的入核。在体内模型中，我们证实了辛酸诱导分化后的GBM细胞的肿瘤恶性程度显著降低，小鼠的生存期明显延长。本研究的完成，证明脂肪酸代谢可驱动GBM细胞的恶性表型向良性表型的转变，为GBM的诱导分化疗法提供了一个靶向新策略。