Difference between revisions of "Domenis 2012 Int J Mol Sci"
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|abstract=Warburg's hypothesis has been challenged by a number of studies showing that oxidative phosphorylation is repressed in some tumors, rather than being inactive per se. Thus, treatments able to shift energy metabolism by activating mitochondrial pathways have been suggested as an intriguing basis for the optimization of antitumor strategies. In this study, HepG2 hepatocarcinoma cells were cultivated with different metabolic substrates under conditions mimicking "positive" (activation/biogenesis) or "negative" (silencing) mitochondrial adaptation. In addition to the expected up-regulation of mitochondrial biogenesis, glucose deprivation caused an increase in phosphorylating respiration and a rise in the expression levels of the ATP synthase β subunit and Inhibitor Factor 1 (IF1). Hyperglycemia, on the other hand, led to a markedly decreased level of the transcriptional coactivator PGC-α suggesting down-regulation of mitochondrial biogenesis, although no change in mitochondrial mass and no impairment of phosphorylating respiration were observed. Moreover, a reduction in mitochondrial networking and in ATP synthase dimer stability was produced. No effect on β-ATP synthase expression was elicited. Notably, hyperglycemia caused an increase in IF1 expression levels, but it did not alter the amount of IF1 associated with ATP synthase. These results point to a new role of IF1 in relation to high glucose utilization by tumor cells, in addition to its well known effect upon mitochondrial ATP synthase regulation. | |abstract=Warburg's hypothesis has been challenged by a number of studies showing that oxidative phosphorylation is repressed in some tumors, rather than being inactive per se. Thus, treatments able to shift energy metabolism by activating mitochondrial pathways have been suggested as an intriguing basis for the optimization of antitumor strategies. In this study, HepG2 hepatocarcinoma cells were cultivated with different metabolic substrates under conditions mimicking "positive" (activation/biogenesis) or "negative" (silencing) mitochondrial adaptation. In addition to the expected up-regulation of mitochondrial biogenesis, glucose deprivation caused an increase in phosphorylating respiration and a rise in the expression levels of the ATP synthase β subunit and Inhibitor Factor 1 (IF1). Hyperglycemia, on the other hand, led to a markedly decreased level of the transcriptional coactivator PGC-α suggesting down-regulation of mitochondrial biogenesis, although no change in mitochondrial mass and no impairment of phosphorylating respiration were observed. Moreover, a reduction in mitochondrial networking and in ATP synthase dimer stability was produced. No effect on β-ATP synthase expression was elicited. Notably, hyperglycemia caused an increase in IF1 expression levels, but it did not alter the amount of IF1 associated with ATP synthase. These results point to a new role of IF1 in relation to high glucose utilization by tumor cells, in addition to its well known effect upon mitochondrial ATP synthase regulation. | ||
|keywords=Warburg, HepG2 cells, [[PGC-1α]], hyperglycemia, aglycemia, tumor bioenergetics, inhibitory factor 1 | |keywords=Warburg, HepG2 cells, [[PGC-1α]], hyperglycemia, aglycemia, tumor bioenergetics, inhibitory factor 1 | ||
|mipnetlab=IT Udine Mavelli I, IT Udine Grassi B, | |mipnetlab=IT Udine Mavelli I, IT Udine Grassi B, | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
|organism=Human | |organism=Human | ||
|tissues=Liver | |tissues=Liver | ||
|preparations=Intact | |preparations=Intact cells | ||
|enzymes=Complex V; ATP Synthase | |||
|injuries=Cancer; Apoptosis; Cytochrome c | |||
|couplingstates=OXPHOS | |couplingstates=OXPHOS | ||
| | |instruments=Oxygraph-2k | ||
}} | }} | ||
Revision as of 14:41, 7 August 2013
| Domenis R, Bisetto E, Rossi D, Comelli M, Mavelli I (2012) Glucose-modulated mitochondria adaptation in tumor cells: a focus on ATP synthase and inhibitor factor 1. Int J Mol Sci 13: 1933-1950. |
Domenis R, Bisetto E, Rossi D, Comelli M, Mavelli I (2012) Int J Mol Sci
Abstract: Warburg's hypothesis has been challenged by a number of studies showing that oxidative phosphorylation is repressed in some tumors, rather than being inactive per se. Thus, treatments able to shift energy metabolism by activating mitochondrial pathways have been suggested as an intriguing basis for the optimization of antitumor strategies. In this study, HepG2 hepatocarcinoma cells were cultivated with different metabolic substrates under conditions mimicking "positive" (activation/biogenesis) or "negative" (silencing) mitochondrial adaptation. In addition to the expected up-regulation of mitochondrial biogenesis, glucose deprivation caused an increase in phosphorylating respiration and a rise in the expression levels of the ATP synthase β subunit and Inhibitor Factor 1 (IF1). Hyperglycemia, on the other hand, led to a markedly decreased level of the transcriptional coactivator PGC-α suggesting down-regulation of mitochondrial biogenesis, although no change in mitochondrial mass and no impairment of phosphorylating respiration were observed. Moreover, a reduction in mitochondrial networking and in ATP synthase dimer stability was produced. No effect on β-ATP synthase expression was elicited. Notably, hyperglycemia caused an increase in IF1 expression levels, but it did not alter the amount of IF1 associated with ATP synthase. These results point to a new role of IF1 in relation to high glucose utilization by tumor cells, in addition to its well known effect upon mitochondrial ATP synthase regulation. • Keywords: Warburg, HepG2 cells, PGC-1α, hyperglycemia, aglycemia, tumor bioenergetics, inhibitory factor 1
• O2k-Network Lab: IT Udine Mavelli I, IT Udine Grassi B
Labels:
Stress:Cancer; Apoptosis; Cytochrome c"Cancer; Apoptosis; Cytochrome c" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property. Organism: Human Tissue;cell: Liver Preparation: Intact cells Enzyme: Complex V; ATP Synthase"Complex V; ATP Synthase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property.
Coupling state: OXPHOS
HRR: Oxygraph-2k
