2102Ep embryonal carcinoma cells have compromised respiration and shifted bioenergetic profile distinct from H9 human embryonic stem cells

Recent studies have shown that cellular bioenergetics may be involved in stem cell differentiation. Considering that during cancerogenesis cells acquire numerous properties of stem cells, it is possible to assume that the energy metabolism in tumorigenic cells might be differently regulated. The aim of this study was to compare the mitochondrial bioenergetic profile of normal pluripotent human embryonic stem cells (hESC) and relatively nullipotent embryonal carcinoma cells (2102Ep cell line). We examined three parameters related to cellular bioenergetics: phosphotransfer system, aerobic glycolysis, and oxygen consumption. Activities and expression levels of main enzymes that facilitate energy transfer were measured. The oxygen consumption rate studies were performed to investigate the respiratory capacity of cells. 2102Ep cells showed a shift in energy distribution towards adenylate kinase network. The total AK activity was almost 3 times higher in 2102Ep cells compared to hESCs (179.85 ± 5.73 vs 64.39 ± 2.55 mU/mg of protein) and the expression of AK2 was significantly higher in these cells, while CK was downregulated. 2102Ep cells displayed reduced levels of oxygen consumption and increased levels of aerobic glycolysis compared to hESCs. The compromised respiration of 2102Ep cells is not the result of increased mitochondrial mass, increased proton leak, and reduced respiratory reserve capacity of the cells or impairment of respiratory chain complexes. Our data showed that the bioenergetic profile of 2102Ep cells clearly distinguishes them from normal hESCs. This should be considered when this cell line is used as a reference, and highlight the importance of further research concerning energy metabolism of stem cells

Simple oxygraphic analysis for the presence of adenylate kinase 1 and 2 in normal and tumor cells

International audienceBackground: Chronic obstructive pulmonary disease (COPD) is characterized by the inability of patients to sustaina high level of ventilation resulting in perceived exertional discomfort and limited exercise capacity of leg musclesat average intracellular ATP levels sufficient to support contractility.Methods: Myosin ATPase activity in biopsy samples from healthy and COPD individuals was implemented as alocal nucleotide sensor to determine ATP diffusion coefficientswithin myofibrils. Ergometric parameters clinicallymeasured during maximal exercise tests in both groups were used to define the rates of myosin ATPase reactionand aerobic ATP re-synthesis. The obtained parameters in combinationwith AK- and CK-catalyzed reactionswere implemented to compute the kinetic and steady-state spatial ATP distributions within control and COPDsarcomeres.Results: The developed reaction–diffusionmodel of two-dimensional sarcomeric space identified similar, yet extremelylow nucleotide diffusion in normal and COPD myofibrils. The corresponding spatio-temporal ATP distributions,constructed during imposed exercise, predicted in COPD sarcomeres a depletion of ATP in the zones ofoverlap between actin and myosin filaments along the center axis at average cytosolic ATP levels similar tohealthy muscles.Conclusions: ATP-depleted zones can induce rigor tension foci impairing muscle contraction and increase a riskfor sarcomere damages. Thus, intra-sarcomeric diffusion restrictions at limited aerobic ATP re-synthesis can bean additional risk factor contributing to the muscle contractile deficiency experienced by COPD patients.General significance: This study demonstrates how restricted substrate mobility within a cellular organelle canprovoke an energy imbalance state paradoxically occurring at abounding average metabolic resources

Comparative analysis of the bioenergetics of human adenocarcinoma Caco-2 cell line and postoperative tissue samples from colorectal cancer patients

The aim of this work was to explore the key bioenergetic properties attributed to the mitochondrial respiration in widely used Caco-2 cell line and human colorectal cancer (HCC) postoperational tissue samples. Oxygraphy and Metabolic Control Analysis (MCA) were applied to estimate the function of oxidative phosphorylation in cultured Caco-2 cells and HCC tissue samples. The mitochondria of Caco-2 cells and HCC tissues displayed larger functional activity of respiratory complex (C)II compared to CI, whereas in normal colon tissue an inverse pattern in the ratio of CI to CII activity was observed. MCA showed that the respiration in Caco-2 and HCC tissue cells is regulated by different parts of electron transport chain. In HCC tissue, this control is performed essentially at the level of respiratory chain complexes I-IV, whereas in Caco-2 cells at the level of CIV (cytochrome c oxidase) and ATP synthasome. The revealed differences in the regulation of respiratory chain activity and glycose index could represent an adaptive response to distinct growth conditions; this means the importance of proper validation of results obtained from in vitro models before their extrapolation to the more complex in vivo systems.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Mitochondrial Respiration in Human Colorectal and Breast Cancer Clinical Material Is Regulated Differently

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