Metabolic response of glioblastoma cells associated with glucose withdrawal and pyruvate substitution as revealed by GC-MS (original) (raw)
Related papers
CNS Oncology, 2012
part of to provide energy and biomolecules regardless of the availability of oxygen. This shift toward increased glycolytic flux and away from the tricarboxylic acid cycle and oxidative phosphorylation occurs very early in tumorigenesis, prior to hypoxia while the tumor has sufficient oxygen. Since Warburg's discovery, metabolism has been of interest in the cancer field, but it often seemed overshadowed by discoveries of oncogenes, tumor suppressor genes, growth factor pathways, molecular subtypes of cancers and so on. There is a resurgence of interest in metabolism as a central theme in cancer, and we continue to find that metabolic pathways intersect and often regulate key components of tumor initiation, progression and therapy response [6,7]. Thus, it has been suggested that one promising therapeutic strategy is to exploit the metabolic dysregulation seen in virtually all tumor cells.
The Suitability of Glioblastoma Cell Lines as Models for Primary Glioblastoma Cell Metabolism
Cancers, 2020
In contrast to most non-malignant tissue, cells comprising the brain tumour glioblastoma (GBM) preferentially utilise glycolysis for metabolism via “the Warburg effect”. Research into therapeutics targeting the disease’s highly glycolytic state offer a promising avenue to improve patient survival. These studies often employ GBM cell lines for in vitro studies which translate poorly to the in vivo patient context. The metabolic traits of five of the most used GBM cell lines were assessed and compared to primary GBM and matched, healthy brain tissue. In patient-derived GBM cell lines, the basal mitochondrial rate (p = 0.043) and ATP-linked respiration (p < 0.001) were lower than primary adjacent normal cells from the same patient, while reserve capacity (p = 0.037) and Krebs cycle capacity (p = 0.002) were higher. Three cell lines, U251MG, U373MG and D54, replicate the mitochondrial metabolism of primary GBM cells. Surprisingly, glycolytic capacity is not different between healthy ...
Cancers are one of the leading causes of morbidity and mortality worldwide, accounting for 8.8 million deaths in 2015 [1, 2]. In the US, it is estimated that 1,688,780 new cancers will be diagnosed in 2017 [3] and 600,920 people will die from this disease in 2017. Gliomas are a highly heterogeneous tumor, refractory to treatment and the most frequently diagnosed primary brain tumor. In 2017, an estimated 23,800 new cases of brain tumors will be diagnosed, and 16,700 will die from a brain tumor, most attributed to glioma [3]. Gliomas are neuroepithelial tumors that originate from the supporting glial cells of the central nervous system (CNS). Glial tumors mostly consist of astrocytomas and oligodendrogliomas. The 2016 WHO classification of CNS tumors uses molecular genetic parameters in addition to histology to define many tumor entities [4]. The routine assessment of isocitrate dehydrogenase (IDH) mutation status, which are frequent in grade II and III infiltrating gliomas and small subset of glioblastomas (GBM) improves histological diagnostic accuracy and has been observed to have a favorable prognostic implication for all glial tumors [5-7] and to be predictive for chemotherapeutic responses in anaplastic oligodendrogliomas with codeletion of 1p/19q chromosomes. Glial tumors that contain chromosomal codeletion of 1p/19q, also defined as tumors of oligodendroglial lineage, have favorable prognosis. GBM typically lack IDH mutations and are instead characterized by EGFR, PTEN, TP53, PDGFRA, NF1, and CDKN2A/B alternations and TERT prompter mutations [5]. The revised classification thus provides a model that reflects malignant characteristics based on histopathlogical and molecular features of the tumors, offering additional opportunities for improved diagnosis, treatment, and estimating prognosis in the molecular era. Lower grade diffuse gliomas (LGGs) (WHO Grade II-III) have fewer malignant characteristics than high-grade gliomas (WHO Grade IV), and a relatively better clinical prognosis. However, the majority of LGGs eventually progress to high grade gliomas (HGG, WHO Grade III or IV), with death an inevitable outcome [8]. The life expectancymfollowing diagnosis with Grade IV glioblastoma multiforme is 2-4 months without treatment. Survival at 5 years for patients with GBM who receive treatment with concurrentchemoradiotherapy followed by maintenance temozolomide is around 8-14% [9]. Progression free survival for low grade glioma with standard treatment (LGG, WHO Grade I or II) is 8-35 months depending on patient age, tumor size, functional scores, and symptoms [8]. Treatment for LGG includes surgical resection followed by either radiation and chemotherapy or chemotherapy alone, but average survival is still approximately seven (7) years from diagnosis [8]. Although LGG have a less aggressive course than do high-grade gliomas, both tumor, its treatment and the ultimate poor prognosis contribute to increased patient burden with disabling morbidity including decline in neurocognitive functions, seizures and compromised quality of life [8]. Significant gaps exist in how best to manage LGG during active surveillance, a period when patients report significant anxiety, eagerness to reduce disease progression, treatment-related symptoms, and demonstrate significant interest in interventions that can extend their years and quality of survival. Patients with LGG may thus represent an ideal cohort for the evaluation of interventions for secondary chemoprevention and symptom management. Although the current WHO grading system (2016) [4] demonstrates promise towards identifying novel treatment modalities and better prediction of prognosis over time, to date, existing targeted and mono therapy approaches have failed to elicit a robust impact on disease progression and patient survival. It is possible that tumor heterogeneity as well as specifically targeted agents fail because redundant molecular pathways in the tumor make it refractory to such approaches. Additionally, the underlying metabolic pathology, which is significantly altered during neoplastic transformation and tumor progression, is unaccounted for. Although LGG have a less aggressive course than do high-grade gliomas, both tumor and its treatment contribute to increased patient burden with disabling morbidity including decline in neurocognitive functions, seizures and ultimately to progression to HGG. There is thus an urgent need and opportunity for the development of novel, adjunct, secondary chemopreventative strategies targeting patients with LGG to slow or halt progression of LGG to HGG. The recognition and broad applicability of the concepts described by Hanahan and Weinberg [10] – identifying the hallmarks of cancer – has transformed the landscape of cancer prevention and treatment. The hallmarks of cancer constitute an organizing principle for rationalizing the complexities and multi-step development of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis. Additional hallmarks include genome instability, which underlies these hallmarks and generates the genetic diversity that is permissive for their acquisition, and inflammation, which fosters multiple hallmark functions. Based on the conceptual progress made in the last decade, two emerging hallmarks of potential generality were added to this list: reprogramming energy metabolism and evading immune destruction [11]. Abnormal energy metabolism is a consistent feature of most tumor cells across all tissue types [12]. The characteristic metabolic phenotype of tumor cells as compared to non-transformed cells has been well documented. In the 1930s, Otto Warburg observed that tumors exhibit a unique metabolic phenotype characterized by high rates of aerobic glycolysis, or fermentation in the presence of oxygen [13]. Following glycolysis, pyruvate is primarily fermented to lactate despite availability of oxygen. This feature, known as the Warburg effect, is characterized by tumor hypoxia, genetic mutations, and mitochondrial abnormalities within proliferating cancer cells [14]. The rapid and unbridled proliferation characteristic of tumor growth is an energy and resource-consuming process, and thus predictably, metabolism is significantly altered during neoplastic transformation and tumor progression [15]. The Warburg effect confers multiple growth promoting effects onto the tumor, including provision of ATP in the face of hypoxia, acidification of the tumor microenvironment, regeneration of endogenous antioxidants, and provision of carbon sources for biomass production, among others [15].
Metabolic state of glioma stem cells and nontumorigenic cells
Proceedings of the National Academy of Sciences, 2011
Gliomas contain a small number of treatment-resistant glioma stem cells (GSCs), and it is thought that tumor regrowth originates from GSCs, thus rendering GSCs an attractive target for novel treatment approaches. Cancer cells rely more on glycolysis than on oxidative phosphorylation for glucose metabolism, a phenomenon used in 2-[ 18 F]fluoro-2-deoxy-D-glucose positron emission tomography imaging of solid cancers, and targeting metabolic pathways in cancer cells has become a topic of considerable interest. However, if GSCs are indeed important for tumor control, knowledge of the metabolic state of GSCs is needed. We hypothesized that the metabolism of GSCs differs from that of their progeny. Using a unique imaging system for GSCs, we assessed the oxygen consumption rate, extracellular acidification rate, intracellular ATP levels, glucose uptake, lactate production, PKM1 and PKM2 expression, radiation sensitivity, and cell cycle duration of GSCs and their progeny in a panel of glioma cell lines. We found GSCs and progenitor cells to be less glycolytic than differentiated glioma cells. GSCs consumed less glucose and produced less lactate while maintaining higher ATP levels than their differentiated progeny. Compared with differentiated cells, GSCs were radioresistant, and this correlated with a higher mitochondrial reserve capacity. Glioma cells expressed both isoforms of pyruvate kinase, and inhibition of either glycolysis or oxidative phosphorylation had minimal effect on energy production in GSCs and progenitor cells. We conclude that GSCs rely mainly on oxidative phosphorylation. However, if challenged, they can use additional metabolic pathways. Therefore, targeting glycolysis in glioma may spare GSCs.
Nontoxic Targeting of Energy Metabolism in Preclinical VM-M3 Experimental Glioblastoma
Frontiers in nutrition, 2018
Temozolomide (TMZ) is part of the standard of care for treating glioblastoma multiforme (GBM), an aggressive primary brain tumor. New approaches are needed to enhance therapeutic efficacy and reduce toxicity. GBM tumor cells are dependent on glucose and glutamine while relying heavily on aerobic fermentation for energy metabolism. Restricted availability of glucose and glutamine may therefore reduce disease progression. Calorically restricted ketogenic diets (KD-R), which reduce glucose and elevate ketone bodies, offer a promising alternative in targeting energy metabolism because cancer cells cannot effectively burn ketones due to defects in the number, structure, and function of mitochondria. Similarly, oxaloacetate, which participates in the deamination of glutamate, has the potential to reduce the negative effects of excess glutamate found in many brain tumors, while hyperbaric oxygen therapy can reverse the hypoxic phenotype of tumors and reduce growth. We hypothesize that the ...
Neurochemical Research, 2019
No major advances have been made in improving overall survival for glioblastoma (GBM) in almost 100 years. The current standard of care (SOC) for GBM involves immediate surgical resection followed by radiotherapy with concomitant temozolomide chemotherapy. Corticosteroid (dexamethasone) is often prescribed to GBM patients to reduce tumor edema and inflammation. The SOC disrupts the glutamate-glutamine cycle thus increasing availability of glucose and glutamine in the tumor microenvironment. Glucose and glutamine are the prime fermentable fuels that underlie therapy resistance and drive GBM growth through substrate level phosphorylation in the cytoplasm and the mitochondria, respectively. Emerging evidence indicates that ketogenic metabolic therapy (KMT) can reduce glucose availability while elevating ketone bodies that are neuroprotective and non-fermentable. Information is presented from preclinical and case report studies showing how KMT could target tumor cells without causing neurochemical damage thus improving progression free and overall survival for patients with GBM.
Reversed metabolic reprogramming as a measure of cancer treatment efficacy in rat C6 glioma model
PLOS ONE
Background Metabolism in tumor shifts from oxidative phosphorylation to inefficient glycolysis resulting in overproduction of lactate (Warburg effect), and cancers may be effectively treated if this imbalance were corrected. The aim of this longitudinal study of glioblastoma in a rat model was to determine whether the ratio of lactate (surrogate marker for glycolysis) to bicarbonate (for oxidative phosphorylation), as measured via in vivo magnetic resonance imaging of hyperpolarized 13 C-labeled pyruvate accurately predicts survival. Methods C6 Glioma implanted male Wistar rats (N = 26) were treated with an anti-vascular endothelial growth factor antibody B20.4.1.1 in a preliminary study to assess the efficacy of the drug. In a subsequent longitudinal survival study, magnetic resonance spectroscopic imaging (MRSI) was used to estimate [1-13 C]Lactate and [1-13 C]Bicarbonate in tumor and contralateral normal appearing brain of glioma implanted rats (N = 13) after injection of hyperpolarized [1-13 C]Pyruvate at baseline and 48 hours post-treatment with B20.4.1.1. Results A survival of~25% of B20.4.1.1 treated rats was noted in the preliminary study. In the longitudinal imaging experiment, changes in 13 C Lactate, 13 C Bicarbonate and tumor size measured at baseline and 48 hours post-treatment did not correlate with survival. 13 C Lactate to 13 C Bicarbonate ratio increased in all the 6 animals that succumbed to the tumor whereas the ratio decreased in 6 of the 7 animals that survived past the 70-day observation period. Conclusions 13 C Lactate to 13 C Bicarbonate ratio (Lac/Bic) at 48 hours post-treatment is highly predictive of survival (p = 0.003). These results suggest a potential role for the 13 C Lac/Bic ratio serving as a valuable measure of tumor metabolism and predicting therapeutic response.
Inhibition of Metabolic Shift can Decrease Therapy Resistance in Human High-Grade Glioma Cells
Pathology & Oncology Research
The high-grade brain malignancy, glioblastoma multiforme (GBM), is one of the most aggressive tumours in central nervous system. The developing resistance against recent therapies and the recurrence rate of GBMs are extremely high. In spite several new ongoing trials, GBM therapies could not significantly increase the survival rate of the patients as significantly. The presence of inter-and intra-tumoral heterogeneity of GBMs arise the problem to find both the pre-existing potential resistant clones and the cellular processes which promote the adaptation mechanisms such as multidrug resistance, stem cell-ness or metabolic alterations, etc. In our work, the in situ metabolic heterogeneity of high-grade human glioblastoma cases were analysed by immunohistochemistry using tissue-microarray. The potential importance of the detected metabolic heterogeneity was tested in three glioma cell lines (grade III-IV) using protein expression analyses (Western blot and WES Simple) and therapeutic drug (temozolomide), metabolic inhibitor treatments (including glutaminase inhibitor) to compare the effects of rapamycin (RAPA) and glutaminase inhibitor combinations in vitro (Alamar Blue and SRB tests). The importance of individual differences and metabolic alterations were observed in mono-therapeutic failures, especially the enhanced Rictor expressions after different monotreatments in correlation to lower sensitivity (temozolomide, doxycycline, etomoxir, BPTES). RAPA combinations with other metabolic inhibitors were the best strategies except for RAPA+glutaminase inhibitor. These observations underline the importance of multi-targeting metabolic pathways. Finally, our data suggest that the detected metabolic heterogeneity (the high mTORC2 complex activity, enhanced expression of Rictor, p-Akt, p-S6, CPT1A, and LDHA enzymes in glioma cases) and the microenvironmental or treatment induced metabolic shift can be potential targets in combination therapy. Therefore, it should be considered to map tissue heterogeneity and alterations with several cellular metabolism markers in biopsy materials after applying recently available or new treatments.
A Supplemented High-Fat Low-Carbohydrate Diet for the Treatment of Glioblastoma
Clinical cancer research : an official journal of the American Association for Cancer Research, 2015
Dysregulated energetics coupled with uncontrolled proliferation has become a hallmark of cancer, leading to increased interest in metabolic therapies. Glioblastoma (GB) is highly malignant, very metabolically active and typically resistant to current therapies. Dietary treatment options based on glucose deprivation have been explored using a restrictive ketogenic diet (KD), with positive anti-cancer reports. However, negative side effects and a lack of palatability makes the KD difficult to implement in an adult population. Hence, we developed a less stringent, supplemented high-fat low-carbohydrate (sHFLC) diet that mimics the metabolic and anti-tumor effects of the KD, maintains a stable nutritional profile and presents an alternative clinical option for diverse patient populations. The dietary paradigm was tested in-vitro and in-vivo, utilizing multiple patient-derived gliomasphere lines. Cellular proliferation, clonogenic frequency and tumor stem cell population effects were det...