Glutaminase isoforms expression switches microRNA levels and oxidative status in glioblastoma cells.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Redox status in the sentinel lymph node of women with breast cancer.

BACKGROUND: Lymphatic metastasis is regulated in multiple steps including the transit of tumor cells via the lymphatic vessels and the successful seeding in draining lymph nodes. Thus, several molecular signals and cellular changes must be involved in this complex process to facilitate tumor cell entry, colonization, and survival in the lymph node. To our knowledge, the present work explores, for the first time in the literature, the redox status (oxidative stress parameters and enzymatic and non-enzymatic antioxidant defense systems) in the sentinel lymph node (SLN) of women with breast cancer. PATIENTS AND METHODS: SLNs from 75 women with breast cancer were identified using the one-step nucleic acid amplification (OSNA) method as negative (n = 43), with micrometastases (n = 13), or with macrometastases (n = 19). It will allow us to gain knowledge about the pro-oxidant/antioxidant mechanisms involved in the processes of distant metastases in breast cancer and also to assess whether these parameters may be alternative techniques for staging. RESULTS: We found different levels of lipid peroxidation in SLNs with micrometastases (increased) and macrometastases (decreased), a decrease in carbonyl group content in SLNs with macrometastases only, and an increase in total antioxidant capacity (TAC) in SNLs with micrometastases and macrometastases. A decrease in the levels of reduced glutathione (GSH) also appears in the SLNs with macrometastases only. Finally, we show increased levels of superoxide dismutase (SOD) and catalase (CAT) activity in SLNs with micrometastases and macrometastases, and decreased levels of glutathione peroxidase (GPx) activity in SNLs with macrometastases but not with micrometastases. CONCLUSIONS: Redox status of lymph node microenvironment participates in the progression of metastatic breast cancer.