Oxidative Phosphorylation For Energy Production Research Articles

Warburg Effect in Oncology

The Warburg effect, defined by cancer cells’ preference for aerobic glycolysis over mitochondrial oxidative phosphorylation for energy production, has been a central topic in cancer research since its identification in 1924. This process involves elevated glucose uptake and lactate production, even in the presence of oxygen, supporting rapid cell proliferation, immune evasion, and promoting angiogenesis and metastasis. In this review, we examine the molecular mechanisms underlying the Warburg effect, focusing on its impact on cancer progression and neurodegenerative disorders. High lactate levels play a critical role in metabolic reprogramming, contributing to tumor growth and survival. Diagnostic tools such as positron emission tomography (PET) and magnetic resonance spectroscopy (MRS) demonstrate increased glycolytic activity in aggressive cancers, while metabolic profiling provides deeper insights into cancer development. Mitochondrial dysfunction serves as a key link between cancer and neurodegenerative diseases, revealing shared metabolic pathways between these conditions. This review also explores the therapeutic potential of methylene blue, a long-established drug, in altering energy metabolism via mitochondrial pathways, offering promise for both cancer treatment and neuroprotection in conditions like Alzheimer's and Parkinson's diseases.

Inhibition of mitochondrial citrate shuttle alleviates metabolic syndromes induced by high-fat diet.

The mitochondrial citrate shuttle, which relies on the solute carrier family 25 member 1 (SLC25A1), plays a pivotal role in transporting citrate from the mitochondria to the cytoplasm. This shuttle supports glycolysis, lipid biosynthesis, and protein acetylation. Previous research has primarily focused on SLC25A1 in pathological models, particularly high-fat diet (HFD)-induced obesity. However, the impact of SLC25A1 inhibition on nutrient metabolism under HFD remains unclear. To address this gap, we used zebrafish (Danio rerio) and Nile tilapia (Oreochromis niloticus) to evaluate the effects of inhibiting Slc25a1. In zebrafish, we administered Slc25a1-specific inhibitors (CTPI-2) for 4 wk, whereas Nile tilapia received intraperitoneal injections of dsRNA to knock down slc25a1b for 7 days. Inhibition of the mitochondrial citrate shuttle effectively protected zebrafish from HFD-induced obesity, hepatic steatosis, and insulin resistance. Of note, glucose tolerance was unaffected. Inhibition of Slc25a1 altered hepatic protein acetylation patterns, with decreased cytoplasmic acetylation and increased mitochondrial acetylation. Under HFD conditions, Slc25a1 inhibition promoted fatty acid oxidation and reduced hepatic triglyceride (TAG) accumulation by deacetylating carnitine palmitoyltransferase 1a (Cpt1a). In addition, Slc25a1 inhibition triggered acetylation-induced inactivation of Pdhe1α, leading to a reduction in glucose oxidative catabolism. This was accompanied by enhanced glucose uptake and storage in zebrafish livers. Furthermore, Slc25a1 inhibition under HFD conditions activated the SIRT1/PGC1α pathway, promoting mitochondrial proliferation and enhancing oxidative phosphorylation for energy production. Our findings provide new insights into the role of nonhistone protein acetylation via the mitochondrial citrate shuttle in the development of hepatic lipid deposition and hyperglycemia caused by HFD.NEW & NOTEWORTHY The mitochondrial citrate shuttle is a crucial physiological process for maintaining metabolic homeostasis. In the present study, we found that inhibition of mitochondrial citrate shuttle (Slc25a1) could alleviate metabolic syndromes induced by high-fat diet (HFD) through remodeling hepatic protein acetylation modification. Briefly, Slc25a1 inhibition reduces hepatic triglyceride deposition by deacetylating Cpt1a and reduces glucose oxidative catabolism by acetylating Pdhe1α. Our study provides new insights into the treatment of diet-induced metabolic syndromes.

PDK4-mediated metabolic reprogramming is a potential therapeutic target for neovascular age-related macular degeneration

Age-related macular degeneration (AMD) causes severe blindness in the elderly due to choroidal neovascularization (CNV), which results from the dysfunction of the retinal pigment epithelium (RPE). While normal RPE depends exclusively on mitochondrial oxidative phosphorylation for energy production, the inflammatory conditions associated with metabolic reprogramming of the RPE play a pivotal role in CNV. Although mitochondrial pyruvate dehydrogenase kinase (PDK) is a central node of energy metabolism, its role in the development of CNV in neovascular AMD has not been investigated. In the present study, we used a laser-induced CNV mouse model to evaluate the effects of Pdk4 gene ablation and treatment with pan-PDK or specific PDK4 inhibitors on fluorescein angiography and CNV lesion area. Among PDK isoforms, only PDK4 was upregulated in the RPE of laser-induced CNV mice, and Pdk4 gene ablation attenuated CNV. Next, we evaluated mitochondrial changes mediated by PDK1-4 inhibition using siRNA or PDK inhibitors in inflammatory cytokine mixture (ICM)-treated primary human RPE (hRPE) cells. PDK4 silencing only in ICM-treated hRPE cells restored mitochondrial respiration and reduced inflammatory cytokine secretion. Likewise, GM10395, a specific PDK4 inhibitor, restored oxidative phosphorylation and decreased ICM-induced upregulation of inflammatory cytokine secretion. In a laser-induced CNV mouse model, GM10395 significantly alleviated CNV. Taken together, we demonstrate that specific PDK4 inhibition could be a therapeutic strategy for neovascular AMD by preventing mitochondrial metabolic reprogramming in the RPE under inflammatory conditions.

Abstract 2037: Enhanced chemosensitivity to DNA-damaging agents in human high-grade glioma through 2-DG treatment

Abstract Background: Human high-grade gliomas are aggressive brain cancers known for their resistance to treatment. Targeted therapies with single agents have shown limited success, and the presence of tumor heterogeneity complicates treatment. Combining multiple chemotherapeutic agents has emerged as a potential strategy to overcome these challenges. 2-deoxy-D-glucose (2-DG) is a glucose analog known for its ability to disrupt glycolysis, protein folding, and the pentose phosphate pathway. This disruption renders cancer cells more susceptible to further damage from reactive oxygen species and DNA damage. Previous studies have demonstrated synergistic effects when combining 2-DG with chemotherapeutic drugs in various cancers. Our study examines combining 2-DG with DNA-damaging agents for high-grade gliomas to uncover potential synergies, theorizing that this combination enhances cell death and metabolic stress, offering insights for better treatments against these tumors. Methods: The cell proliferation, clonogenic growth, and cell migration assays assessed viability, clonogenic formation, and migration. Additionally, the cell cycle and reactive oxygen species analysis were employed to evaluate cell division, oxidative stress, and antioxidant capacity. The Illumina NovaSeq 6000 platform measured transcript levels, and Liquid Chromatography-High-Resolution Mass Spectrometry analyzed metabolite changes in high-grade glioma cell lines following 2-DG treatment. The Agilent Seahorse Mito Stress Test evaluated alterations in cellular bioenergetics. SYNERGYFINDER 3 quantified synergistic effects of 2-DG with DNA-damaging agents, while the Annexin V-FITC Conjugates and a ROS multiplex assay assessed cell death and metabolic stress. Results: Our findings demonstrate that when used as a single agent, 2-DG induces cell senescence and limits cell migration but is insufficient to trigger cell death. Moreover, 2-DG treatment shifts glioma cells towards oxidative phosphorylation for energy production, elevates ROS levels, and hampers DNA synthesis and repair mechanisms. Our synergy study reveals promising synergistic effects when combining 2-DG with DNA-damaging agents, including 5-FU, Methotrexate, Gemcitabine, and Lomustine. This combined therapy leads to significant ROS generation and increased cell death compared to single-agent treatments. Furthermore, prolonged exposure to 2-DG leads to increased levels of both glucogenic and ketogenic amino acids within glioma cells, potentially serving as an alternative energy source. This finding hints at a prospective therapeutic approach for targeting drug-resistant cells. Conclusions: Our results suggest that the anticancer therapeutic effect of 2-DG is enhanced when used in combination with DNA-damaging agents, indicating this strategy as a potential approach for treating human high-grade glioma. Citation Format: Tracy Miller, Esther Jane, Matthew Halbert, Taylor Gatesman, Stacey Wendell, Dinesh Mohanakrishnan, Sameer Agnihotri, Daniel Premkumar, Ian Pollack. Enhanced chemosensitivity to DNA-damaging agents in human high-grade glioma through 2-DG treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2037.

Construction of an oxidative phosphorylation-related gene signature for predicting prognosis and identifying immune infiltration in osteosarcoma.

Osteosarcoma is a prevalent malignant tumor that originates from mesenchymal tissue. It typically affects children and adolescents. Although it is known that the growth of osteosarcoma relies on oxidative phosphorylation for energy production, limited attention has been paid to exploring the potential of oxidative phosphorylation-related genes in predicting the prognosis of individuals suffering from osteosarcoma. All the data were retrieved from the UCSC Xena and GEO (GENE EXPRESSION OMNIBUS). Identification of the oxidative phosphorylation genes linked to the prognosis of individuals with osteosarcoma was done by means of univariate COX and LASSO regression analyses. Following that, patients were categorized into a high-risk group and a low-risk group as per the risk score determined by the identified oxidative phosphorylation genes. Furthermore, a comparison was made in terms of the survival and immune infiltration between both groups, and the prognostic model was established. Five oxidative phosphorylation genes (ATP6V0D1, LHPP, COX6A2, MTHFD2, NDUFB9) associated with the prognosis of individuals with osteosarcoma were identified and the risk prognostic models were constructed. In the current research, the analysis of the ROC curves indicated a superior predictive accuracy exhibited by the risk model. The prognosis was adversely affected by immune infiltration in the high-risk group in comparison with the low-risk group. The function of the oxidative phosphorylation-related prognostic gene set was verified by GO and KEGG analysis. Furthermore, the link between oxidative phosphorylation-related genes and osteosarcoma immune infiltration was examined by GSEA analysis. In this study, a prognostic model that demonstrated good predictive performance was constructed. Additionally, this study highlighted a correlation between oxidative phosphorylation-related genes and immune infiltration.

Glycolysis-Stimulated Esrrb Lactylation Promotes the Self-Renewal and Extraembryonic Endoderm Stem Cell Differentiation of Embryonic Stem Cells.

Embryonic stem cells (ESCs) favor glycolysis over oxidative phosphorylation for energy production, and glycolytic metabolism is critical for pluripotency establishment, maintenance, and exit. However, an understanding of how glycolysis regulates the self-renewal and differentiation of ESCs remains elusive. Here, we demonstrated that protein lactylation, regulated by intracellular lactate, contributes to the self-renewal of ESCs. We further showed that Esrrb, an orphan nuclear receptor involved in pluripotency maintenance and extraembryonic endoderm stem cell (XEN) differentiation, is lactylated on K228 and K232. The lactylation of Esrrb enhances its activity in promoting ESC self-renewal in the absence of the LIF and XEN differentiation of ESCs by increasing its binding at target genes. Our studies reveal the importance of protein lactylation in the self-renewal and XEN differentiation of ESCs, and the underlying mechanism of glycolytic metabolism regulating cell fate choice.

Targeting Metabolic Pathways Improves TNBC Therapy

Breast cancer (BC) accounts for a significant proportion of female tumor cases globally. Triple-negative breast cancer (TNBC) is its most difficult variant, which is defined by the absence of the estrogen receptor, progesterone receptor, and HER2 expression. Aerobic glycolysis (Warburg effect) plays a pivotal role in TNBC, influencing both tumor microenvironment and immune responses. TNBC cells undergo metabolic reprogramming, favoring glycolysis over oxidative phosphorylation for energy production, leading to lactate accumulation and extracellular acidification in the tumor milieu, which exacerbates tumor proliferation, metastasis, and immunosuppression. This review delves into key glycolytic enzymes and regulators, including hexokinase, phosphofructokinase, pyruvate kinase M2, lactate dehydrogenase, and monocarboxylate transporters, as potential therapeutic targets. Highlighting promising preclinical evidence and clinical studies utilizing glycolytic pathway modulators, the review underscores their potential to reduce TNBC cell viability, curb growth, inhibit metastasis, and enhance chemosensitivity. Chemotherapy is still the most commonly used systemic treatment for TNBC, although immunotherapy, especially employing PD-1 and PD-L1 inhibitors, has advanced despite obstacles in the metastatic setting due to TNBC heterogeneity and changed immunogenicity. This review underscores the urgent need for tailored, effective therapies for TNBC patients, especially those with metastatic disease, shedding light on strategies to harness glycolysis for improving treatment outcomes.

Undernutrition-induced substance metabolism and energy production disorders affected the structure and function of the pituitary gland in a pregnant sheep model.

Undernutrition spontaneously occurs in ewes during late gestation and the pituitary is an important hinge in the neurohumoral regulatory system. However, little is known about the effect of undernutrition on pituitary metabolism. Here, 10 multiparous ewes were restricted to a 30% feeding level during late gestation to establish an undernutrition model while another 10 ewes were fed normally as controls. All the ewes were sacrificed, and pituitary samples were collected to perform transcriptome, metabolome, and quantitative real-time PCR analysis and investigate the metabolic changes. PCA and PLS-DA of total genes showed that undernutrition changed the total transcriptome profile of the pituitary gland, and 581 differentially expressed genes (DEGs) were identified between the two groups. Clusters of orthologous groups for eukaryotic complete genomes demonstrated that substance transport and metabolism, including lipids, carbohydrates, and amino acids, energy production and conversion, ribosomal structure and biogenesis, and the cytoskeleton were enriched by DEGs. Kyoto encyclopedia of genes and genomes pathway enrichment analysis displayed that the phagosome, intestinal immune network, and oxidative phosphorylation were enriched by DEGs. Further analysis found that undernutrition enhanced the lipid degradation and amino acid transport, repressing lipid synthesis and transport and amino acid degradation of the pituitary gland. Moreover, the general metabolic profiles and metabolic pathways were affected by undernutrition, repressing the 60S, 40S, 28S, and 39S subunits of the ribosomal structure for translation and myosin and actin synthesis for cytoskeleton. Undernutrition was found also to be implicated in the suppression of oxidative phosphorylation for energy production and conversion into a downregulation of genes related to T cell function and the immune response and an upregulation of genes involved in inflammatory reactions enriching phagosomes. This study comprehensively analyses the effect of undernutrition on the pituitary gland in a pregnant sheep model, which provides a foundation for further research into the mechanisms of undernutrition-caused hormone secretion and metabolic disorders.

The Pro-Oncogenic Protein IF1 Promotes Proliferation of Anoxic Cancer Cells during Re-Oxygenation.

Cancer cells overexpress IF1, the endogenous protein that inhibits the hydrolytic activity of ATP synthase when mitochondrial membrane potential (ΔμH+) falls, as in ischemia. Other roles have been ascribed to IF1, but the associated molecular mechanisms are still under debate. We investigated the ability of IF1 to promote survival and proliferation in osteosarcoma and colon carcinoma cells exposed to conditions mimicking ischemia and reperfusion, as occurs in vivo, particularly in solid tumors. IF1-silenced and parental cells were exposed to the FCCP uncoupler to collapse ΔμH+ and the bioenergetics of cell models were validated. All the uncoupled cells preserved mitochondrial mass, but the implemented mechanisms differed in IF1-expressing and IF1-silenced cells. Indeed, the membrane potential collapse and the energy charge preservation allowed an increase in both mitophagy and mitochondrial biogenesis in IF1-expressing cells only. Interestingly, the presence of IF1 also conferred a proliferative advantage to cells highly dependent on oxidative phosphorylation when the uncoupler was washed out, mimicking cell re-oxygenation. Overall, our results indicate that IF1, by allowing energy preservation and promoting mitochondrial renewal, can favor proliferation of anoxic cells and tumor growth. Therefore, hindering the action of IF1 may be promising for the therapy of tumors that rely on oxidative phosphorylation for energy production.

To chase or not to chase: A case report on warburg effect in a patient with Meningioma

The Warburg Effect (WE) is an uncommon cause of type B lactic acidosis usually found in hematological malignancies which preferred glycolysis rather than oxidative phosphorylation for energy production. We report a case of a 50-years old lady with left parasaggital meningioma presented with unusual type B lactic acidosis intraoperatively.

Loss of selenoprotein W in murine macrophages alters the hierarchy of selenoprotein expression, redox tone, and mitochondrial functions during inflammation

Macrophages play a pivotal role in mediating inflammation and subsequent resolution of inflammation. The availability of selenium as a micronutrient and the subsequent biosynthesis of selenoproteins, containing the 21st amino acid selenocysteine (Sec), are important for the physiological functions of macrophages. Selenoproteins regulate the redox tone in macrophages during inflammation, the early onset of which involves oxidative burst of reactive oxygen and nitrogen species. SELENOW is a highly expressed selenoprotein in bone marrow-derived macrophages (BMDMs). Beyond its described general role as a thiol and peroxide reductase and as an interacting partner for 14-3-3 proteins, its cellular functions, particularly in macrophages, remain largely unknown. In this study, we utilized Selenow knock-out (KO) murine bone marrow-derived macrophages (BMDMs) to address the role of SELENOW in inflammation following stimulation with bacterial endotoxin lipopolysaccharide (LPS). RNAseq-based temporal analyses of expression of selenoproteins and the Sec incorporation machinery genes suggested no major differences in the selenium utilization pathway in the Selenow KO BMDMs compared to their wild-type counterparts. However, selective enrichment of oxidative stress-related selenoproteins and increased ROS in Selenow−/− BMDMs indicated anomalies in redox homeostasis associated with hierarchical expression of selenoproteins. Selenow−/− BMDMs also exhibited reduced expression of arginase-1, a key enzyme associated with anti-inflammatory (M2) phenotype necessary to resolve inflammation, along with a significant decrease in efferocytosis of neutrophils that triggers pathways of resolution. Parallel targeted metabolomics analysis also confirmed an impairment in arginine metabolism in Selenow−/− BMDMs. Furthermore, Selenow−/− BMDMs lacked the ability to enhance characteristic glycolytic metabolism during inflammation. Instead, these macrophages atypically relied on oxidative phosphorylation for energy production when glucose was used as an energy source. These findings suggest that SELENOW expression in macrophages may have important implications on cellular redox processes and bioenergetics during inflammation and its resolution.

You are what you eat: How to best fuel your immune system.

Normal bone marrow (BM) homeostasis ensures consistent production of progenitor cells and mature blood cells. This requires a reliable supply of nutrients in particular free fatty acids, carbohydrates and protein. Furthermore, rapid changes can occur in response to stress such as infection which can alter the demand for each of these metabolites. In response to infection the haematopoietic stem cells (HSCs) must respond and expand rapidly to facilitate the process of emergency granulopoiesis required for the immediate immune response. This involves a shift from the use of glycolysis to oxidative phosphorylation for energy production and therefore an increased demand for metabolites. Thus, the right balance of each dietary component helps to maintain not only normal homeostasis but also the ability to quickly respond to systemic stress. In addition, some dietary components can drive chronic inflammatory changes in the absence of infection or immune stress, which in turn can impact on overall immune function. The optimal nutrition for the best immunological outcomes would therefore be a diet that supports the functions of immune cells allowing them to initiate effective responses against pathogens but also to resolve the response rapidly when necessary and to avoid any underlying chronic inflammation. In this review we discuss how these key dietary components can alter immune function, what is their impact on bone marrow metabolism and how changes in dietary intake of each of these can improve the outcomes of infections.

Immunohistochemical evaluation and prognostic value of monocarboxylate transporter 1 (MCT1) and 4 (MCT4) in T-cell non-Hodgkin lymphoma.

Tumor cells often exhibit the Warburg effect, wherein, they preferentially undergo glycolysis over oxidative phosphorylation for energy production. Monocarboxylate transporter 1 (MCT1) and 4 (MCT4) are critical symporters mediating lactate efflux and preventing intracellular acidification during tumor growth. Numerous studies have focused on inhibiting MCT1 or MCT4 in various cancers. However, its role in T-cell lymphoma (TCL) is not yet investigated owing to the low incidence of TCL. This study was designed to investigate the expression of MCT1/MCT4 in patients with TCL and determine their prognostic value in this cancer. We performed immunohistochemistry to evaluate the expression level of MCT1/MCT4 in 38 TCL tissue samples and then compared their expression among different TCL subgroups, which were formed based on different clinical characteristics. Survival analysis was performed to evaluate the relationship between MCT1/MCT4 expression and both overall survival (OS) and progression-free survival (PFS). Our results revealed that MCT1 and MCT4 expression was significantly increased in TCL tissues compared to the control group. In addition, increased MCT1 expression associated with the female sex, advanced disease stage, increased serum LDH, Ki-67 at ≥ 50%, and intermediate or high-risk groups as categorized by the International Prognostic Index (IPI) score. We also found that increased MCT1 expression may be associated with reduced OS and PFS. In conclusion, MCT1 and MCT4 are overexpressed in patients with TCL and may predict poor prognosis. MCT1 inhibition might be a novel treatment strategy for TCL, and further preclinical trials are required.

High Metabolic Dependence on Oxidative Phosphorylation Drives Sensitivity to Metformin Treatment in MLL/AF9 Acute Myeloid Leukemia.

Simple SummaryAcute myeloid leukemia is a group of metabolic heterogeneous cancers, of which the long-term overall survival is still poor, especially in elderly patients. Targeting metabolic reprogramming in leukemic cells is becoming a promising strategy. The aim of our research was to explore the relation of genetic mutations with the metabolic phenotype and potential therapeutics to target metabolic pathway dependence. We confirmed the metabolic heterogeneity in AML cell lines and found the high dependence on oxidative phosphorylation in MLL/AF9 AML cells. Metformin could significantly repress the proliferation of MLL/AF9 AML cells by inhibiting oxidative phosphorylation.Acute myeloid leukemia (AML) is a group of hematological cancers with metabolic heterogeneity. Oxidative phosphorylation (OXPHOS) has been reported to play an important role in the function of leukemic stem cells and chemotherapy-resistant cells and are associated with inferior prognosis in AML patients. However, the relationship between metabolic phenotype and genetic mutations are yet to be explored. In the present study, we demonstrate that AML cell lines have high metabolic heterogeneity, and AML cells with MLL/AF9 have upregulated mitochondrial activity and mainly depend on OXPHOS for energy production. Furthermore, we show that metformin repressed the proliferation of MLL/AF9 AML cells by inhibiting mitochondrial respiration. Together, this study demonstrates that AML cells with an MLL/AF9 genotype have a high dependency on OXPHOS and could be therapeutically targeted by metformin.

TAMI-14. REDUCTION IN S. CEREVISIAE GROWTH AND CELL VIABILITY IN RESPONSE TO D-2-HYDROXYGLUTARATE ACCUMULATION IS DAMPENED BY GROWTH CONDITIONS PERMISSIVE OF OXIDATIVE PHOSPHORYLATION

Abstract BACKGROUND Elevated levels of D-2-hydroxyglutarate (D2HG) have been detected in several cancers, including IDH1/2 mutant gliomas, PHGDH-amplified breast cancer, diffuse large B-cell lymphomas which harbor loss-of-function mutations in D2HG dehydrogenase gene (D2HGDH), and MYC-amplified breast cancers. Given the high degree of conservation between the yeast and human isocitrate dehydrogenases the similarities between yeast and cancer glycolytic metabolism, we hypothesized that a yeast model would allow for the successful recapitulation of metabolic dysregulation by D2HG. METHODS A heteroallelic idp1 R148H yeast strain was created (equivalent to human IDH2 R172H). The growth characteristics of this strain and the dld3∆ strain (equivalent to D2HGDH loss of function) were evaluated with glucose or galactose carbon source. Octyl-D2HG, a cell permeable mimic of D2HG, was used to assess the effects of D2HG accumulation at varying concentration. FACS was used to measure cell viability, reactive oxygen species (ROS) production, and mitochondrial membrane potential. Analysis of the synthetic lethal genetic array for the dld3∆ strain was performed. RESULTS Accumulation of D2HG in mutant and wild-type yeast strains results in impaired growth and reduction in cell viability in a concentration dependent manner. The negative effect on growth and cell viability is more prominent when cells are not utilizing oxidative phosphorylation for energy production (glucose versus galactose carbon source). D-2HG accumulation results in ROS production in dld3∆ but not in the heteroallelicidp1 R148H yeast strain. An increase in mitochondrial membrane potential occurs in both strains when grown with galactose, but not in glucose. The top negative genetic interactors with dld3∆ include genes involved in mitochondrial function. CONCLUSIONS We found that yeast cells have different sensitivity to the toxic effects of D-2HG depending on the metabolic status of the cell. This suggests that altering cell metabolism may be a viable therapeutic target in cancers with excess production of D2HG such as IDH mutant gliomas.

Glycometabolism regulates hepatitis C virus release.

HCV cell-culture system uses hepatoma-derived cell lines for efficient virus propagation. Tumor cells cultured in glucose undergo active aerobic glycolysis, but switch to oxidative phosphorylation for energy production when cultured in galactose. Here, we investigated whether modulation of glycolysis in hepatocytes affects HCV infection. We showed HCV release, but not entry, genome replication or virion assembly, is significantly blocked when cells are cultured in galactose, leading to accumulation of intracellular infectious virions within multivesicular body (MVB). Blockade of the MVB-lysosome fusion or treatment with pro-inflammatory cytokines promotes HCV release in galactose. Furthermore, we found this glycometabolic regulation of HCV release is mediated by MAPK-p38 phosphorylation. Finally, we showed HCV cell-to-cell transmission is not affected by glycometabolism, suggesting that HCV cell-to-supernatant release and cell-to-cell transmission are two mechanistically distinct pathways. In summary, we demonstrated glycometabolism regulates the efficiency and route of HCV release. We proposed HCV may exploit the metabolic state in hepatocytes to favor its spread through the cell-to-cell transmission in vivo to evade immune response.

Abstract 97: Pathway-based classification of glioblastoma uncovers a mitochondrial subtype with therapeutic vulnerabilities

Abstract Transcriptomic classification has been used to molecularly characterize glioblastoma (GBM) but has failed to predict survival and inform on pharmacologic vulnerability. Here, we developed a computational approach for the unbiased identification of the core biological pathways that optimally classify individual glioma cells and bulk tumors. Using single cell RNA-sequencing data from 36 high-grade gliomas, we uncovered four transcriptional states that exist along two evolutionary axes, a metabolic axis including mitochondrial and glycolytic/pluri-metabolic and a neurodevelopmental axis including proliferative/progenitor and neuronal states. The activation of the same set of biological pathways independently stratified primary GBM into four subtypes, among which the mitochondrial subgroup was associated with the most favorable clinical outcome. By integrating genomic, transcriptomic, DNA methylation, microRNA and proteomics analysis, we found that mitochondrial GBM was enriched with coherent gain-of-function of mitochondrial genes and loss-of-function alterations targeting glycolysis and alternative metabolic programs, suggesting that this subgroup may fail to produce compensatory metabolism. Mitochondrial GBM relied exclusively on oxidative phosphorylation for energy production whereas the glycolytic/pluri-metabolic subtype was sustained by concurrent activation of multiple metabolic fluxes including aerobic glycolysis, amino acid consumption and lipid synthesis and storage. Deletion of SLC45A1, a gene coding for a glucose-H+ symporter on chromosome 1p36.23, emerged as the truncal genetic alteration most significantly associated with mitochondrial GBM. Reintroduction of SLC45A1 in mitochondrial GBM cells harboring SLC45A1 gene deletion induced cytoplasmic acidification, loss of cell fitness and growth arrest. The strict dependency of mitochondrial GBM on mitochondrial respiration was associated with excessive generation of reactive oxygen species and unique sensitivity to inhibitors of oxidative phosphorylation. Collectively, this work presents a classification of GBM that informs clinical outcome and identifies patients who are more likely to benefit from therapies targeting metabolic vulnerabilities. Citation Format: Luciano Garofano, Simona Migliozzi, Young Taek Oh, Fulvio D'Angelo, Ryan D. Najac, Aram Ko, Brulinda Frangaj, Francesca Pia Caruso, Kai Yu, Jinzhou Yuan, Wenting Zhao, Anna Luisa Di Stefano, Franck Bielle, Tao Jiang, Peter Sims, Mario L. Suvà, Fuchou Tang, Xiao-Dong Su, Michele Ceccarelli, Marc Sanson, Anna Lasorella, Antonio Iavarone. Pathway-based classification of glioblastoma uncovers a mitochondrial subtype with therapeutic vulnerabilities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 97.

Targeting Lactate Dehydrogenase A with Catechin Resensitizes SNU620/5FU Gastric Cancer Cells to 5-Fluorouracil.

Resistance to anticancer therapeutics occurs in virtually every type of cancer and becomes a major difficulty in cancer treatment. Although 5-fluorouracil (5FU) is the first-line choice of anticancer therapy for gastric cancer, its effectiveness is limited owing to drug resistance. Recently, altered cancer metabolism, including the Warburg effect, a preference for glycolysis rather than oxidative phosphorylation for energy production, has been accepted as a pivotal mechanism regulating resistance to chemotherapy. Thus, we investigated the detailed mechanism and possible usefulness of antiglycolytic agents in ameliorating 5FU resistance using established gastric cancer cell lines, SNU620 and SNU620/5FU. SNU620/5FU, a gastric cancer cell harboring resistance to 5FU, showed much higher lactate production and expression of glycolysis-related enzymes, such as lactate dehydrogenase A (LDHA), than those of the parent SNU620 cells. To limit glycolysis, we examined catechin and its derivatives, which are known anti-inflammatory and anticancer natural products because epigallocatechin gallate has been previously reported as a suppressor of LDHA expression. Catechin, the simplest compound among them, had the highest inhibitory effect on lactate production and LDHA activity. In addition, the combination of 5FU and catechin showed additional cytotoxicity and induced reactive oxygen species (ROS)-mediated apoptosis in SNU620/5FU cells. Thus, based on these results, we suggest catechin as a candidate for the development of a novel adjuvant drug that reduces chemoresistance to 5FU by restricting LDHA.

Pathway-based classification of glioblastoma uncovers a mitochondrial subtype with therapeutic vulnerabilities.

The transcriptomic classification of glioblastoma (GBM) has failed to predict survival and therapeutic vulnerabilities. A computational approach for unbiased identification of core biological traits of single cells and bulk tumors uncovered four tumor cell states and GBM subtypes distributed along neurodevelopmental and metabolic axes, classified as proliferative/progenitor, neuronal, mitochondrial and glycolytic/plurimetabolic. Each subtype was enriched with biologically coherent multiomic features. Mitochondrial GBM was associated with the most favorable clinical outcome. It relied exclusively on oxidative phosphorylation for energy production, whereas the glycolytic/plurimetabolic subtype was sustained by aerobic glycolysis and amino acid and lipid metabolism. Deletion of the glucose-proton symporter SLC45A1 was the truncal alteration most significantly associated with mitochondrial GBM, and the reintroduction of SLC45A1 in mitochondrial glioma cells induced acidification and loss of fitness. Mitochondrial, but not glycolytic/plurimetabolic, GBM exhibited marked vulnerability to inhibitors of oxidative phosphorylation. The pathway-based classification of GBM informs survival and enables precision targeting of cancer metabolism.

The Effect of Angiotensin II, Retinoic Acid, EGCG, and Vitamin C on the Cardiomyogenic Differentiation Induction of Human Amniotic Fluid-Derived Mesenchymal Stem Cells.

Human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) may be potentially applied in cell therapy or regenerative medicine as a new alternative source of stem cells. They could be particularly valuable in restoring cardiac tissue after myocardial infarction or other cardiovascular diseases. We investigated the potential of biologically active compounds, namely, angiotensin II, retinoic acid (RA), epigallocatechin-3-gallate (EGCG), vitamin C alone, and the combinations of RA, EGCG, and vitamin C with angiotensin II to induce cardiomyogenic differentiation of AF-MSCs. We observed that the upregulated expression of cardiac gene markers (NKX2-5, MYH6, TNNT2, and DES) and cardiac ion channel genes (sodium, calcium, the potassium) as well as the increased levels of Connexin 43 and Nkx2.5 proteins. Extracellular flux analysis, applied for the first time on AF-MSCs induced with biologically active compounds, revealed the switch in AF-MSCs energetic phenotype and enhanced utilization of oxidative phosphorylation for energy production. Moreover, we demonstrated changes in epigenetic marks associated with transcriptionally active (H3K4me3, H3K9ac, and H4hyperAc) or repressed (H3K27me3) chromatin. All in all, we demonstrated that explored biomolecules were able to induce alterations in AF-MSCs at the phenotypic, genetic, protein, metabolic, and epigenetic levels, leading to the formation of cardiomyocyte progenitors that may become functional heart cells in vitro or in vivo.