Substrate Oxidation and ATP Supply in AS-30D Hepatoma Cells

Rodrı́guez-Enrı́quez, Sara; Torres-Márquez, M. Eugenia; Moreno‐Sánchez, Rafael

doi:10.1006/abbi.1999.1582

Cited by 76 publications

(72 citation statements)

References 37 publications

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“…49). This was challenged by the finding that hepatoma cells maintained their phosphate potential mainly through respiration (50). Our results point to the fact that an impairment of mitochondrial function is not a prerequisite for Crabtree effect induction since the same arrest of respiration caused by F16bP can be observed in mitochondria obtained from a nontumor source.…”

Section: Discussionmentioning

confidence: 59%

Mitochondrial Oxidative Phosphorylation Is Regulated by Fructose 1,6-Bisphosphate

Díaz-Ruiz

Avéret

Araiza

et al. 2008

Journal of Biological Chemistry

142

109

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In numerous cell types, tumoral cells, proliferating cells, bacteria, and yeast, respiration is inhibited when high concentrations of glucose are added to the culture medium. This phenomenon has been named the "Crabtree effect." We used yeast to investigate (i) the short term event(s) associated with the Crabtree effect and (ii) a putative role of hexose phosphates in the inhibition of respiration. Indeed, yeast divide into "Crabtree-positive," where the Crabtree effect occurs, and "Crabtree-negative," where it does not. In mitochondria isolated from these two categories of yeast, we found that low, physiological concentrations of glucose 6-phosphate and fructose 6-phosphate slightly (20%) stimulated the respiratory flux and that this effect was strongly antagonized by fructose 1,6-bisphosphate (F16bP). On the other hand, F16bP by itself was able to inhibit mitochondrial respiration only in mitochondria isolated from a Crabtree-positive strain. Using permeabilized spheroplasts from Crabtree-positive yeast, we have shown that the sole effect observed at physiological concentrations of hexose phosphates is an inhibition of oxidative phosphorylation by F16bP. This F16bP-mediated inhibition was also observed in isolated rat liver mitochondria, extending this process to mammalian cells. From these results and taking into account that F16bP is able to accumulate in the cell cytoplasm, we propose that F16bP regulates oxidative phosphorylation and thus participates in the establishment of the Crabtree effect.

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Section: Discussionmentioning

confidence: 59%

Mitochondrial Oxidative Phosphorylation Is Regulated by Fructose 1,6-Bisphosphate

Díaz-Ruiz

Avéret

Araiza

et al. 2008

Journal of Biological Chemistry

142

109

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“…The prevalence of GLUT3 in AS-30D hepatocarcinoma and GLUT1 in HeLa cells reflects the physiological environment under which both cancer cell types usually develop. The ascitic fluid in which AS-30D grow has a micromolar concentration of glucose (Rodríguez-Enríquez et al, 2000) making necessary to have a high affinity glucose transporter, whereas HeLa cells are cultured in a medium with a high glucose content of 25 mM, thus, only requiring a low affinity glucose transporter.…”

Section: Identity and Kinetic Parameters Of Glut In Tumor Cellsmentioning

confidence: 99%

Kinetics of transport and phosphorylation of glucose in cancer cells

Rodrı́guez-Enrı́quez

Marín‐Hernández

Gallardo‐Pérez

et al. 2009

Journal Cellular Physiology

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Metabolic control analysis of tumor glycolysis has indicated that hexokinase (HK) and glucose transporter (GLUT) exert the main flux control (71%). To understand why they are the main controlling steps, the GLUT and HK kinetics and the contents of GLUT1, GLUT2, GLUT3, GLUT4, HKI, and HKII were analyzed in rat hepatocarcinoma AS-30D and HeLa human cervix cancer. An improved protocol to determine the kinetic parameters of GLUT was developed with D-[2-(3)H-glucose] as physiological substrate. Kinetic analysis revealed two components at low- and high-glucose concentrations in both tumor cells. At low glucose and 37 degrees C, the V(max) was 55 +/- 20 and 17.2 +/- 6 nmol (min x mg protein)(-1), whereas the K(m) was 0.52 +/- 0.7 and 9.3 +/- 3 mM for hepatoma and HeLa cells, respectively. GLUT activity was partially inhibited by cytochalasin B (IC(50) = 0.44 +/- 0.1; K(i) = 0.3 +/- 0.1 microM) and phloretin (IC(50) = 8.7 microM) in AS-30D hepatocarcinoma. At physiological glucose, GLUT1 and GLUT3 were the predominant active isoforms in HeLa cells and AS-30D cells, respectively. HK activity in HeLa cells was much lower (60 mU/mg protein) than that in AS-30D cells (700 mU/mg protein), but both HKs were strongly inhibited by G6P. HKII was the predominant isoform in AS-30D carcinoma and HeLa cells. The much lower GLUT V(max) and catalytic efficiency (V(max)/K(m)) values in comparison to those of G6P-sensitive HK suggested the transporter exerts higher control on the glycolytic flux than HK in cancer cells. Thus, GLUT seems a more adequate therapeutic target.

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“…MCA of OxPhos in AS-30D hepatocarcinoma showed that the respiratory chain site 1 (30%) and the ATP-consuming enzyme block (protein and nucleic acid synthesis; ion ATPases; 34%) were the main controlling sites [Rodríguez-Enríquez et al, 2000]. The low respiratory site 1 content in AS-30D hepatoma [Rodríguez-Enríquez et al, 2000] seems the reason for its significant flux control. Flux control residing outside of pathway was originally proposed by Hofmeyr and CornishBowden [2000].…”

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confidence: 95%

Multi-biomarker pattern for tumor identification and prognosis

et al. 2011

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In last decades, the basic, clinical, and translational research efforts have been directed to the identification of standard biomarkers associated with the degree of malignancy. There is an increasingly public health concern for earlier detection of cancer development at stages in which successful treatments can be achieved. To meet this urgent clinical demand, early stage cancer biomarkers supported by reliable and robust experimental data that can be readily applicable in the clinical practice, are required. In the current standard protocols, when one or two of the canonical proliferating index biomarkers are analyzed, contradictory results are frequently reached leading to incorrect cancer diagnostic and unsuccessful therapies. Therefore, the identification of other cellular characteristics or signatures present in the tumor cells either alone or in combination with the well-established proliferation markers emerge as an alternative strategy in the improvement of cancer diagnosis and treatment. Because it is well known that several pathways and processes are altered in tumor cells, the concept of "single marker" in cancer results incorrect. Therefore, this review aims to analyze and discuss the proposal that the molecular profile of different genes or proteins in different altered tumor pathways must be established to provide a better global clinical pattern for cancer detection and prognosis.

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Substrate Oxidation and ATP Supply in AS-30D Hepatoma Cells

Cited by 76 publications

References 37 publications

Mitochondrial Oxidative Phosphorylation Is Regulated by Fructose 1,6-Bisphosphate

Mitochondrial Oxidative Phosphorylation Is Regulated by Fructose 1,6-Bisphosphate

Kinetics of transport and phosphorylation of glucose in cancer cells

Multi-biomarker pattern for tumor identification and prognosis

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