Lactate Reprograms Energy and Lipid Metabolism in Glucose-Deprived Oxidative Glioma Stem Cells.

Fast-growing tumors satisfy their bioenergetic needs by supplementing glucose with alternative carbon sources. Cancer stem cells are the most versatile and robust cells within malignant tumors. They avoid potentially lethal metabolic and other types of stress through flexible reprogramming of relevant pathways, but it has remained unclear whether alternative carbon sources are important for the maintenance of their tumor-propagating ability. Here we assessed the ability of glycolytic and oxidative murine glioma stem cells (GSCs) to grow in an ultralow glucose medium. Sphere formation assays revealed that exogenous lactate and acetate reversed the growth impairment of oxidative GSCs in such medium. Extracellular flux analysis showed that lactate supported oxygen consumption in these cells, whereas metabolomics analysis revealed that it increased the intracellular levels of tricarboxylic acid cycle intermediates, ATP, and GTP as well as increased adenylate and guanylate charge. Lactate also reversed the depletion of choline apparent in the glucose-deprived cells as well as reprogrammed phospholipid and fatty acid biosynthesis. This metabolic reprogramming was associated with a more aggressive phenotype of intracranial tumors formed by lactate-treated GSCs. Our results thus suggest that lactate is an important alternative energetic and biosynthetic substrate for oxidative GSCs, and that it sustains their growth under conditions of glucose deprivation.

MicroRNA-183 upregulates HIF-1α by targeting isocitrate dehydrogenase 2 (IDH2) in glioma cells.

MicroRNAs (miRs) are small, non-coding RNAs that regulate gene expression and contribute to cell proliferation, differentiation and metabolism. Our previous study revealed the extensive modulation of a set of miRs in malignant glioma. In that study, miR microarray analysis demonstrated the upregulation of microRNA-183 (miR-183) in glioblastomas. Therefore, we examined the expression levels of miR-183 in various types of gliomas and the association of miR-183 with isocitrate dehydrogenase 2 (IDH2), which has complementary sequences to miR-183 in its 3'-untranslated region (3'UTR). In present study, we used real-time PCR analysis to demonstrate that miR-183 is upregulated in the majority of high-grade gliomas and glioma cell lines compared with peripheral, non-tumorous brain tissue. The mRNA and protein expression levels of IDH2 are downregulated via the overexpression of miR-183 mimic RNA in glioma cells. Additionally, IDH2 mRNA expression is upregulated in glioma cells expressing anti-miR-183. We verified that miR-183 directly affects IDH2 mRNA levels in glioma cells using luciferase assays. In malignant glioma specimens, the expression levels of IDH2 were lower in tumors than in the peripheral, non-tumorous brain tissues. HIF-1α levels were upregulated in glioma cells following transfection with miR-183 mimic RNA or IDH2 siRNA. Moreover, vascular endothelial growth factor and glucose transporter 1, which are downstream molecules of HIF-1α, were upregulated in cells transfected with miR-183 mimic RNA. These results suggest that miR-183 upregulation in malignant gliomas induces HIF-1α expression by targeting IDH2 and may play a role in glioma biology.

Morbidity of stereotactic biopsy for intracranial lesions.

The safety of stereotactic biopsy (STB) was studied in this article. CT-guided STB (Brown-Roberts-Wells; BRW) was performed 58 times for 56 patients (male: 29, female: 27) at Hyogo Cancer Center between 1988 and 2007. The age distribution ranged from 15 to 83 (mean: 55) years old. Histological diagnoses were established for 58 samples, with 35 cases of glioma, eight of metastatic brain tumor, nine of malignant lymphoma and leukemia, two of germ cell tumor, two of abscess, one necrosis, and one case with normal tissue. There were 3 cases (5.2%) in which an intratumoral hemorrhage with neurological deficits was occurred. They were needed surgically removal and those histological pathology revealed glioma. Concerning location of biopsy, STB for basal ganglia (putamen or globus pallidus) and thalamus were caused complication of the intratumoral hematoma after biopsy. The review of the 575 cases indicates that glioma was the relative risk factor for morbidity associated with CT-guided STB (odds ratio 5.36). The overall morbidity rate was 6.4% (37/575). We considered that tumors of the basal ganglia (putamen or globus pallidus), thalamus and glioma were risk factors of morbidity for CT-guided STB.

Glioblastoma multiforme associated with klinefelter syndrome.

A 54-year-old man with Klinefelter syndrome presented with glioblastoma multiforme manifesting as a 2-week history of motor weakness of the bilateral extremities. Magnetic resonance imaging showed multiple heterogeneously enhanced tumors in the bilateral frontal lobes. Angiography showed no tumor stain or arteriovenous shunt. The tumor was partially removed through a right craniotomy. The histological diagnosis was glioblastoma. Immunohistochemical examination showed no O(6)-methylguanine-deoxyribonucleic acid methyltransferase protein expression. Postoperative local radiotherapy (60 Gy/30 fractions) combined with temozolomide (75 mg/m(2) x 42 days) and interferon-beta (3,000,000 U, 3 times/week) was performed. The patient's clinical status rapidly deteriorated during chemoradiotherapy, and he died of tumor progression 3.5 months after the surgery. Postmortem examination revealed widespread glioblastoma infiltrating the basal ganglia and thalamus. Klinefelter syndrome is associated with increased cancer predisposition, especially for male breast cancer and germ cell tumors, but glioma is extremely rare. The abnormal genetic constitution of this patient may have been directly responsible for the poor outcome.

Sca-1 and Thy-1 accelerate neuron-like differentiation in bone marrow stromal cells.

Bone marrow stromal cells taken from EGFP transgenic mice were sorted by magnetic beads with surface markers for Sca-1 and Thy-1. The cells were then co-cultured on organotypic hippocampal slice or with neuronal cell feeder in dish. On hippocampus, both Sca-1 and Thy-1 positive cells showed 4- 8 folds higher potential to show neuron-like morphology than negative cells. In dish, negative cells fewly survived but each positive cells survived and showed neuron-like differentiation. In both culture condition, retinoic acid supplement accelerate differentiation. Differentiated Sca-1 and Thy-1 positive cells were immunohistochemically GFAP- and NeuN-negative but nestin-, neurofilament- and NSE-positive. Neuron-like differentiation of bone marrow cells can be enhanced by selection using cell surface proteins.