Glutaminase isoenzymes GLS and GLS2 play apparently opposing roles in cancer: GLS acts as an oncoprotein, while GLS2 (GAB isoform) has context specific tumour suppressive activity. Some microRNAs (miRNAs) have been implicated in progression of tumours, including gliomas. The aim was to investigate the effect of GLS and GAB expression on both miRNAs and oxidative status in glioblastoma cells. Microarray profiling of miRNA was performed in GLS-silenced LN229 and GAB-transfected T98G human glioblastoma cells and their wild-type counterparts. Results were validated by real-time quantitative RT-PCR. Oxidative status and antioxidant enzymes were determined by spectrophotometric or fluorescence assays in GLS-silenced LN229 and T98G, and GAB-transfected LN229 and T98G. MiRNA-146a-5p, miRNA-140-3p, miRNA-21-5p, miRNA-1260a, and miRNA-92a-3p were downregulated, and miRNA-1246 was upregulated when GLS was knocked down. MiRNA-140-3p, miRNA-1246, miRNA-1260a, miRNA-21-5p, and miRNA-146a-5p were upregulated when GAB was overexpressed. Oxidative status (lipid peroxidation, protein carbonylation, total antioxidant capacity, and glutathione levels), as well as antioxidant enzymes (catalase, superoxide dismutase, and glutathione reductase) of silenced GLS glioblastoma cells and overexpressed GAB glioblastoma cells significantly changed versus their respective control glioblastoma cells. MiRNA-1246, miRNA-1260a, miRNA-146a-5p, and miRNA-21-5p have been characterized as strong biomarkers of glioblastoma proliferation linked to both GLS silencing and GAB overexpression. Total glutathione is a reliable biomarker of glioblastoma oxidative status steadily associated to both GLS silencing and GAB overexpression. Glutaminase isoenzymes are related to the expression of some miRNAs and may contribute to either tumour progression or suppression through certain miRNA-mediated pathways, proving to be a key tool to switch cancer proliferation and redox status leading to a less malignant phenotype. Accordingly, GLS and GAB expression are especially involved in glutathione-dependent antioxidant defence.

中文翻译：

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谷氨酰胺酶同种型表达改变胶质母细胞瘤细胞中的微RNA水平和氧化状态

谷氨酰胺酶同工酶 GLS 和 GLS2 在癌症中起着明显相反的作用：GLS 充当癌蛋白，而 GLS2（GAB 同工型）具有上下文特定的肿瘤抑制活性。一些 microRNA (miRNA) 与肿瘤的进展有关，包括神经胶质瘤。目的是研究 GLS 和 GAB 表达对胶质母细胞瘤细胞中 miRNA 和氧化状态的影响。在 GLS 沉默的 LN229 和 GAB 转染的 T98G 人胶质母细胞瘤细胞及其野生型对应细胞中进行了 miRNA 的微阵列分析。结果通过实时定量RT-PCR验证。在 GLS 沉默的 LN229 和 T98G 以及 GAB 转染的 LN229 和 T98G 中，氧化状态和抗氧化酶通过分光光度法或荧光测定法测定。miRNA-146a-5p、miRNA-140-3p、miRNA-21-5p、miRNA-1260a、当 GLS 被敲低时，miRNA-92a-3p 和 miRNA-92a-3p 被下调，而 miRNA-1246 被上调。当 GAB 过表达时，miRNA-140-3p、miRNA-1246、miRNA-1260a、miRNA-21-5p 和 miRNA-146a-5p 上调。沉默的 GLS 胶质母细胞瘤细胞和过表达的 GAB 胶质母细胞瘤细胞的氧化状态（脂质过氧化、蛋白质羰基化、总抗氧化能力和谷胱甘肽水平）以及抗氧化酶（过氧化氢酶、超氧化物歧化酶和谷胱甘肽还原酶）与其各自的对照胶质母细胞瘤相比发生了显着变化细胞。miRNA-1246、miRNA-1260a、miRNA-146a-5p 和 miRNA-21-5p 已被表征为与 GLS 沉默和 GAB 过表达相关的胶质母细胞瘤增殖的强生物标志物。总谷胱甘肽是胶质母细胞瘤氧化状态的可靠生物标志物，与 GLS 沉默和 GAB 过表达稳定相关。谷氨酰胺酶同工酶与一些 miRNA 的表达有关，可能通过某些 miRNA 介导的途径促进肿瘤进展或抑制，证明是转换癌症增殖和氧化还原状态的关键工具，从而降低恶性表型。因此，GLS 和 GAB 的表达尤其参与了依赖于谷胱甘肽的抗氧化防御。