A computational model elucidates the effects of oncogene-induced expression alterations on the energy metabolism of neuroblastoma

The antimicrobial peptide nisin Z induces selective toxicity and apoptotic cell death in cultured melanoma cells

Background: Altered energy metabolism is one of the hallmarks of cancer. Tumor cells reprogram their energy metabolism to meet the demands of uncontrolled cell division. During tumorigenesis the vast majority of cancer cells become highly glycolytic (Warburg effect) accompanied by a decrease in oxidative metabolism. Chemotherapy is likely to affect the energy metabolism of tumor cells, but how specific drugs affect specific metabolic pathways is only beginning to be addressed. Methods: the effects of cytotoxic agents on energy metabolism were assessed by flow cytometric uptake of Mitotracker®, the ratio of mitochondrial and nuclear DNA on qRT-PCR, western blotting for protein levels of the different complexes of the respiratory chain and oxygen consumption rate by the Seahorse Extracellular Flux Analyzer. Cell death was analyzed by flow cytometric uptake of Propidium Iodide, Nicoletti assay and protein levels of caspases 3 and 8. Results: Gene expression analysis was performed on 119 resected liver metastases of colorectal tumors. Of all clinical variables tested, neoadjuvant chemotherapy was most prominently associated with changes in gene expression. Gene ontology and pathway analysis tools revealed that many of the chemotherapy-associated genes were involved in the regulation of oxidative phosphorylation (OxPhos). To test whether chemotherapy affects OxPhos patient derived colorectal spheroids were treated with the standard cytotoxic agents oxaliplatin and 5-fluorouracil. Chemotherapy strongly increases mitochondrial load, oxygen consumption rate and mitochondrial ATP synthesis. In line with these results chemo-treated tumor cells displayed a higher ratio of mitochondrial-to-nuclear DNA and expression of respiratory complex components was strongly increased following chemotherapy. Chemotherapy strongly induced expression of the histone deacetylase SIRT1, which has been implicated in mitochondrial biogenesis. Inhibition (by either nicotinamide, EX-527, Tenovin-6) or knockdown of SIRT1 prevented the chemotherapy-induced increase in oxidative phosphorylation. Moreover, SIRT1 knockdown greatly reduced tumor cell survival and clonogenic capacity following removal of chemotherapy. Conclusion: Chemotherapy induces an increase in oxidative phosphorylation via SIRT1 and this is required for tumor cell survival following drug removal. Since DNA repair requires ATP, mitochondrial biogenesis may be part of the tumor cell response to DNA-damaging agents. Post-chemotherapy targeting of SIRT1 (or OxPhos enzymes) may be an interesting novel approach to increase chemotherapy efficacy. Citation Format: Thomas T. Vellinga, Vincent C. de Boer, Tijana Borovski, Kari Trumpi, Szabolcs Fatrai, Onno Kranenburg, Inne H.M. Borel Rinkes, Jeroen Hagendoorn. Survival of colorectal cancer cells following chemotherapy relies on a SIRT1-dependent increase in oxidative phosphorylation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3351. doi:10.1158/1538-7445.AM2014-3351

As a hallmark of cancer, metabolic reprogramming adjusts macromolecular synthesis, energy metabolism and redox homeostasis processes to adapt to and promote the complex biological processes of abnormal growth and proliferation. The complexity of metabolic reprogramming lies in its precise regulation by multiple levels and factors, including the interplay of multiple signalling pathways, precise regulation of transcription factors and dynamic adjustments in metabolic enzyme activity. In this complex regulatory network, acetylation and deacetylation, which are important post-translational modifications, regulate key molecules and processes related to metabolic reprogramming by affecting protein function and stability. Dysregulation of acetylation and deacetylation may alter cancer cell metabolic patterns by affecting signalling pathways, transcription factors and metabolic enzyme activity related to metabolic reprogramming, increasing the susceptibility to rapid proliferation and survival. In this review, we focus on discussing how acetylation and deacetylation regulate cancer metabolism, thereby highlighting the central role of these post-translational modifications in metabolic reprogramming, and hoping to provide strong support for the development of novel cancer treatment strategies. KEY POINTS: Protein acetylation and deacetylation are key regulators of metabolic reprogramming in tumour cells. These modifications influence signalling pathways critical for tumour metabolism. They modulate the activity of transcription factors that drive gene expression changes. Metabolic enzymes are also affected, altering cellular metabolism to support tumour growth.

Effect of hypothermia on bilirubin-induced alterations in brain cell membrane function and energy metabolism in newborn piglets

Purpose Renal ischemia-reperfusion injury(IRI)is a major cause of acute kidney injury(AKI), the injury and repair of renal tubular epithelial cells play an important role in the pathological process of IR-AKI. Metabolomics was used to detect cell metabolism alterations and metabolic reprogramming in the initial injury, peak injury, and recovery stage of human renal proximal tubular cells (HK-2 cells) to provide insights into clinical prevention and treatment of IRI-induced AKI. Methods An in vitro ischemia-reperfusion (H/R) injury and the recovery model of HK-2 cells were established at different times of hypoxia/reoxygenation. Comprehensive detection of metabolic alterations in HK-2 cells after H/R induction by nontarget metabolomics. Interconversion of glycolysis and fatty acid oxidation (FAO) in HK-2 cells after H/R induction was examined by western blotting and qRT-PCR. Results Multivariate data analysis found significant differences among the groups, with significant changes in metabolites such as glutamate, malate, aspartate, and L-palmitoylcarnitine. Hypoxia-reoxygenated HK-2 cells are accompanied by altered metabolisms such as disturbance of amino acid and nucleotide metabolism, dysregulation of lipid metabolism, increased glycolysis, and metabolic reprogramming, which manifests as a shift in energy metabolism from FAO to glycolysis. Conclusion The development of IRI-induced AKI in HK-2 cells is accompanied by the disturbance of amino acid, nucleotide, and tricarboxylic acid cycle metabolism and specifically metabolic reprogramming of FAO to glycolytic conversion. The timely recovery of energy metabolism in HK-2 cells is of great significance for treating and prognosis IRI-induced AKI.

Cancer is a leading cause of human death worldwide, and the modulation of the metabolic properties of T cells employed in cancer immunotherapy holds great promise for combating cancer. As a crucial factor, energy metabolism influences the activation, proliferation, and function of T cells, and thus metabolic reprogramming of T cells is a unique research perspective in cancer immunology. Special conditions within the tumor microenvironment and high-energy demands lead to alterations in the energy metabolism of T cells. In-depth research on the reprogramming of energy metabolism in T cells can reveal the mechanisms underlying tumor immune tolerance and provide important clues for the development of new tumor immunotherapy strategies as well. Therefore, the study of T cell energy metabolism has important clinical significance and potential applications. In the study, the current achievements in the reprogramming of T cell energy metabolism were reviewed. Then, the influencing factors associated with T cell energy metabolism were introduced. In addition, T cell energy metabolism in cancer immunotherapy was summarized, which highlighted its potential significance in enhancing T cell function and therapeutic outcomes. In summary, energy exhaustion of T cells leads to functional exhaustion, thus resulting in immune evasion by cancer cells. A better understanding of reprogramming of T cell energy metabolism may enable immunotherapy to combat cancer and holds promise for optimizing and enhancing existing therapeutic approaches.

Evidence for altered energy metabolism, increased lactate, and decreased pH in schizophrenia brain: A focused review and meta-analysis of human postmortem and magnetic resonance spectroscopy studies

Metabolic reprogramming, including enhanced biosynthesis of macromolecules, altered energy metabolism, and maintenance of redox homeostasis, is considered a hallmark of cancer, sustaining cancer cell growth. Multiple signaling pathways, transcription factors and metabolic enzymes participate in the modulation of cancer metabolism and thus, metabolic reprogramming is a highly complex process. Recent studies have observed that ubiquitination and deubiquitination are involved in the regulation of metabolic reprogramming in cancer cells. As one of the most important type of post-translational modifications, ubiquitination is a multistep enzymatic process, involved in diverse cellular biological activities. Dysregulation of ubiquitination and deubiquitination contributes to various disease, including cancer. Here, we discuss the role of ubiquitination and deubiquitination in the regulation of cancer metabolism, which is aimed at highlighting the importance of this post-translational modification in metabolic reprogramming and supporting the development of new therapeutic approaches for cancer treatment.

Tumor cells rely mainly on glycolysis for energy production even in the presence of sufficient oxygen, a phenomenon termed the Warburg effect, which is the most outstanding characteristic of energy metabolism in cancer cells. This metabolic adaptation is believed to be critical for tumor cell growth and proliferation, and a number of onco-proteins and tumor suppressors, including the PI3K/Akt/mTOR signaling pathway, Myc, hypoxia-inducible factor and p53, are involved in the regulation of this metabolic adaptation. Moreover, glycolytic cancer cells are often invasive and impervious to therapeutic intervention. Thus, altered energy metabolism is now appreciated as a hallmark of cancer and a promising target for cancer treatment. A better understanding of the biology and the regulatory mechanisms of aerobic glycolysis has the potential to facilitate the development of glycolysis-based therapeutic interventions for cancer. In addition, glycolysis inhibition combined with DNA damaging drugs or chemotherapeutic agents may be effective anticancer strategies through weakening cell damage repair capacity and enhancing drug cytotoxicity.

We evaluated the effects of 7-nitroindazole, a selective neuronal nitric oxide synthetase (nNOS) inhibitor, on bilirubin-induced alterations in brain cell membrane function and energy metabolism in the newborn piglets. The decreased cerebral cortical cell membrane Na⁺,K⁺-ATPase activity and increased lipid peroxidation products, indicative of bilirubin-induced brain damage, were significantly attenuated by 7-nitroindazole treatment. 7-Nitroindazole also significantly improved the bilirubin-induced reduction in both brain ATP and phosphocreatine levels, decreased blood-to-brain glucose ratio and increased brain lactate level. In summary, 7-nitroindazole significantly attenuated the bilirubin-induced alterations in brain cell membrane function and energy metabolism in the newborn piglet. These findings suggest that nitric oxide produced by nNOS is involved in mediating or facilitating bilirubin-induced cerebral dysfunction.

Early alterations in cardiac energy metabolism and lipotoxicity are crucial factors in the pathogenesis and progression of diabetic cardiomyopathy (DCM). The excessive accumulation of lipid metabolic intermediates within the myocardium can lead to increased production of reactive oxygen species (ROS) and promote apoptosis. Pigment epithelium-derived factor (PEDF) has been shown to regulate cardiac energy metabolism; however, its role in modulating energy metabolism, ROS generation, and apoptosis in the context of DCM requires further investigation. PEDF was overexpressed in db/db mice via tail vein injection of adeno-associated virus 9(AAV9)-PEDF. At week 24, assessments were conducted on cardiac hypertrophy, fibrosis, cardiac function, and alterations in energy metabolism. Additionally, H9c2 cells were transfected with a PEDF plasmid and cultured under HG+PA conditions (33mm glucose + 250μM palmitic acid) for 24hours. Subsequent analyses focused on changes in energy metabolism, ROS levels, and apoptosis. At 24weeks, db/db mice exhibited hallmark features of DCM, including hyperglycemia, hyperlipidemia, cardiac hypertrophy, fibrosis, and diastolic dysfunction. Overexpression of PEDF reversed cardiac remodeling in these mice. In both db/db mice and HG+PA-treated H9c2 cells, PEDF overexpression modulated cardiac energy metabolism, mitigated lipotoxicity, and promoted the expression of adipose triglyceride lipase(ATGL) and glucose transporter type 4(Glut4) while inhibiting the expression of peroxisome proliferator-activated receptor alpha (PPARα), carnitine palmitoyltransferase 1 alpha (CPT1α), and scavenger receptor B2 (CD36). Additionally, PEDF overexpression reduced ROS generation and apoptosis in db/db mice myocardium and HG+PA-treated h9c2 cells. PEDF can effectively prevent cardiac hypertrophy, fibrosis remodeling, and the deterioration of diastolic dysfunction in DCM by modulating cardiac energy metabolism and mitigating ROS production and apoptosis induced by lipotoxicity.

Epidemiological data links higher parity and lack of breastfeeding with increased risk of breast cancer, specifically aggressive triple negative breast cancer, and associated higher mortality rate. Long-term breastfeeding and gradual weaning of an infant leads to gradual involution (GI) of the breast, while lack of or abrupt discontinuation of breastfeeding after birth leads to abrupt involution (AI), when rapid and massive cell death takes place. Our studies show several precancerous changes, such as increased collagen deposition, inflammation, and hyperplasia in the mammary gland (MG) of mice after AI1. Recent studies indicate peroxisome proliferator-activated receptor-gamma coactivator 1-apha (PGC1α) as a regulator of involution and energy metabolism. As metabolic reprogramming is a hallmark of cancer, metabolic changes in the MG related to involution warrant investigation. Objective: Our objective was to evaluate the metabolic effects of AI in MG. We hypothesized that AI leads to marked alteration in mammary lipid metabolism, mitochondrial biogenesis, and oxidative stress through elevations of PGC1α, which cause long-term metabolic reprogramming and genomic instability. Methods: FVB/n mice were paired for breeding. At partum, dams were randomized to AI or GI cohort and standardized to 6 pups per dam. AI mice had pups removed on day 7 postpartum (PPM). For GI mice 3 pups each were removed on day 28 and 31ppm. Tissues were harvested on day 28, 56, and 120 PPM. MG were subjected to Affymetrix, Gene Set Enrichment Analysis (GSEA), Seahorse Analysis, and lipidomics. Results were validated by qPCR and Western Blot. Superoxide species were detected by flow cytometry. DNA damage was analyzed via 8-hydroxy-2’-deoxygnuanosine (8-OHdG) ELISA. Results: Day 28 AI glands had significantly higher PGC1α expression than GI glands (p=0.006). Affymetrix and GSEA data showed day 28 AI glands to have enriched pathways related to fatty acid metabolism (p=0.004) and oxidative phosphorylation (p<0.001). Lipidomics showed elevated levels of oxidized sphingolipids and production of prostaglandin J2 (PGJ2) in day 28 AI glands (all p<0.02). Day 56 AI glands had higher levels of mitochondria superoxide species (p<0.0001) and higher PGJ2 synthesis (p=0.01). Day 120 AI MG had upregulation of an oxidized lipid (p=0.0476). Day 120 AI glands had significantly higher 8-OHdG levels (p=0.02), higher reliance of fatty acid substrates for energy (p=0.0185), and elevated extracellular acidification rates (p=0.0194). Conclusion: Although histologically both GI and AI MG return to near pre-pregnancy state within a month, our data shows long-term metabolic reprogramming in the AI MG similar to what is shown in breast cancer cells. These metabolic changes link to early elevations in PGC1α. Addressing the metabolic changes by targeting PGC1α provide a potential option to reduce the risk of developing breast cancer if a woman is unable to breastfeed. PMID6637535 *Fellowship T32CA229114 Citation Format: Kate S Ormiston, Kirti Kaul, Neelam Shinde, Gautam Sarathy, Morgan Bauer, Djawed Bennouna, Rachel Kopec, Ramesh Ganju, Sarmila Majumder, Bhuvaneswari Ramaswamy. Elevated PGC1α during abrupt mammary gland involution leads to long-term metabolic reprogramming and genomic instability; hallmarks of breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A045.

Background and Objective Liver cancer is a highly malignant tumor, and patients typically have poor prognoses. Metabolic reprogramming is a hallmark of cancer, and downregulation of oxoglutarate dehydrogenase-like (OGDHL) contributes to the onset and progression of several cancers. We examined the role of altered OGDHL expression in liver cancer and determined its value as a diagnostic and prognostic indicator for patients. Material and Methods R (version 3.5.1) and several R extensions were used for data mining of The Cancer Genome Atlas (TCGA) dataset (including RNAseq and clinical information) and statistical analysis. Receiver operating characteristic analysis was used to determine the diagnostic value of OGDHL. The chi-squared test was used to identify the clinical correlates of OGDHL downregulation. Survival analysis (with the log-rank test) and univariate and multivariate Cox analysis were used to evaluate the effect of OGDHL expression on overall survival (OS) and relapse-free survival. TCGA was used for analysis of gene set enrichment. ResultsOGDHL had lower expression in cancerous liver tissues than noncancerous adjacent tissues, and low expression correlated with more advanced patient age, histologic grade, stage, T classification, and poor survival. Patients with lower OGDHL expression had shorter OS and relapse-free survival. Multivariate Cox regression indicated that low OGDHL expression was an independent risk factor for poor prognosis. Gene set enrichment analysis indicated enrichment of the mitotic spindle, G2M checkpoint, and E2F targets in the OGDHL low expression phenotype. ConclusionOGDHL has potential as a diagnostic and prognostic biomarker for liver cancer.

While normal differentiated cells primarily use mitochondrial respiration to generate the required energy for cellular processes, most cancer cells rely on glycolysis, even in sufficient oxygen conditions. This phenomenon is known as the "Warburg effect" or aerobic glycolysis and the metabolic reprogramming of cancer cells towards this altered energy metabolism is currently recognized as one of the "hallmarks of cancer". Aerobic glycolysis underlies the rapid growth of tumor cells, with high rates of glucose consumption and lactic acid production, leading to cellular acidosis. Metabolic reprogramming renders cancer cells dependent on specific metabolic enzymes or pathways that could be exploited in cancer therapy. The development of treatments that target tumor glucose metabolism is receiving renewed attention, with several drugs targeting metabolic pathways currently in clinical trials. The search for suitable targets, however, is limited by the high plasticity of the metabolic network that can induce compensatory routes. Deregulated glucose metabolism is a prominent feature associated with resistance to classical chemotherapy or oncogene-targeted therapies, strengthening the clinical potential of combining these therapies with glycolysis inhibitors. The aim of this review is to compare the advances of different therapeutic strategies targeting the glucose "addiction" of tumor cells, highlighting their potential as effective weapons against cancer. We further discuss recent evidence for the involvement of glucose metabolism as a compensatory response to the use of drugs that target different signaling pathways, where the combination with glycolysis inhibitors could prove extraordinarily useful.

Acute administration of l-tyrosine alters energetic metabolism of hippocampus and striatum of infant rats