胱氨酸/谷氨酸逆向转运蛋白 xCT 的过度表达与高克隆性胶质母细胞瘤干细胞样细胞 (GSC) 中的营养灵活性和 ZEB1 表达相关

发表日期：2022-01-05

Overexpression of Cystine/Glutamate Antiporter xCT Correlates with Nutrient Flexibility and ZEB1 Expression in Highly Clonogenic Glioblastoma Stem-like Cells (GSCs)

胱氨酸/谷氨酸逆向转运蛋白 xCT 的过度表达与高克隆性胶质母细胞瘤干细胞样细胞 (GSC) 中的营养灵活性和 ZEB1 表达相关

Glioblastoma (GBM) is the most aggressive form of glioma (WHO grade IV), and mounting evidence suggests that glioblastoma stem-like cells (GSCs) play an important role in tumor growth and response to therapy. In the current study, we sought to understand the metabolic dependencies of GSCs using high-resolution proton magnetic resonance spectroscopy (1H-NMR). In a defined experimental setting, we stratified in vitro GSC models into two subtypes (Gln/GluHigh, Gln/GluLow) and used diverse molecular approaches to perform comprehensive analyses in GSC neurosphere cultures and primary GBM samples.

胶质母细胞瘤 (GBM) 是最具侵袭性的胶质瘤形式（WHO IV 级），越来越多的证据表明，胶质母细胞瘤干细胞样细胞 (GSC) 在肿瘤生长和治疗反应中发挥着重要作用。在当前的研究中，我们试图使用高分辨率质子磁共振波谱 ( 1 H-NMR)来了解 GSC 的代谢依赖性。在定义的实验环境中，我们将体外 GSC 模型分为两个亚型（Gln/Glu高、Gln/Glu低），并使用不同的分子方法对 GSC 神经球培养物和原代 GBM 样本进行综合分析。

三角细胞摇瓶

Cancer stem-like cells mediate tumor initiation, progression, and therapy resistance; however, their identification and selective eradication remain challenging. Herein, we analyze the metabolic dependencies of glioblastoma stem-like cells (GSCs) with high-resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. We stratify our in vitro GSC models into two subtypes primarily based on their relative amount of glutamine in relationship to glutamate (Gln/Glu). Gln/GluHigh GSCs were found to be resistant to glutamine deprivation, whereas Gln/GluLow GSCs respond with significantly decreased in vitro clonogenicity and impaired cell growth. The starvation resistance appeared to be mediated by an increased expression of the glutamate/cystine antiporter SLC7A11/xCT and efficient cellular clearance of reactive oxygen species (ROS). Moreover, we were able to directly correlate xCT-dependent starvation resistance and high Gln/Glu ratios with in vitro clonogenicity, since targeted differentiation of GSCs with bone morphogenic protein 4 (BMP4) impaired xCT expression, decreased the Gln/Glu ratio, and restored the sensitivity to glutamine starvation. Moreover, significantly reduced levels of the oncometabolites lactate (Lac), phosphocholine (PC), total choline (tCho), myo-inositol (Myo-I), and glycine (Gly) were observed in differentiated GSCs. Furthermore, we found a strong association between high Gln/Glu ratios and increased expression of Zinc finger E-box-binding homeobox 1 (ZEB1) and xCT in primary GBM tumor tissues. Our analyses suggest that the inhibition of xCT represents a potential therapeutic target in glioblastoma; thus, we could further extend its importance in GSC biology and stress responses. We also propose that monitoring of the intracellular Gln/Glu ratio can be used to predict nutrient stress resistance.

10层细胞工厂

癌症干细胞样细胞介导肿瘤的发生、进展和治疗抵抗；然而，它们的识别和选择性根除仍然具有挑战性。在此，我们使用高分辨率质子核磁共振 ( 1 H-NMR) 光谱分析了胶质母细胞瘤干细胞样细胞 (GSC) 的代谢依赖性。我们主要根据谷氨酰胺与谷氨酸 (Gln/Glu) 的相对量将我们的体外 GSC 模型分为两个亚型。发现Gln/Glu高GSCs 对谷氨酰胺剥夺具有抵抗力，而 Gln/Glu低GSCs 以显着降低的体外克隆形成和受损的细胞生长作出反应。饥饿抗性似乎是由谷氨酸/胱氨酸逆向转运蛋白 SLC7A11/xCT 的表达增加和活性氧 (ROS) 的有效细胞清除介导的。此外，我们能够将 xCT 依赖性饥饿抗性和高 Gln/Glu 比率与体外克隆形成直接相关联，因为具有骨形态发生蛋白 4（BMP4）的 GSC 的靶向分化损害了 xCT 表达，降低了 Gln/Glu 比率，并恢复了对谷氨酰胺饥饿的敏感性。此外，在分化的 GSC 中观察到癌代谢物乳酸 (Lac)、磷酸胆碱 (PC)、总胆碱 (tCho)、肌醇 (Myo-I) 和甘氨酸 (Gly) 的水平显着降低。此外，我们发现高 Gln/Glu 比率与锌指 E-box 结合同源框 1 (ZEB1) 和 xCT 在原发性 GBM 肿瘤组织中的表达增加之间存在很强的关联。我们的分析表明，xCT 的抑制代表了胶质母细胞瘤的潜在治疗靶点；因此，我们可以进一步扩展其在 GSC 生物学和应激反应中的重要性。我们还建议监测细胞内 Gln/Glu 比率可用于预测营养胁迫抗性。