Inhibition of energy-producing pathways of HepG2 cells by 3-bromopyruvate1 (original) (raw)
Research Article| January 16 2009
Ana Paula Pereira Da Silva
*Laboratório de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373 – CCS, Bl. D, ss13, 21941-902, RJ, Brazil
†Laboratório de Bioquímica de Vírus, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, RJ, Brazil
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†Laboratório de Bioquímica de Vírus, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, RJ, Brazil
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*Laboratório de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373 – CCS, Bl. D, ss13, 21941-902, RJ, Brazil
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Reinaldo Sousa Dos Santos
*Laboratório de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373 – CCS, Bl. D, ss13, 21941-902, RJ, Brazil
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*Laboratório de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373 – CCS, Bl. D, ss13, 21941-902, RJ, Brazil
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‡Centro Nacional de Ressonância Magnética Nuclear Jiri Jonas-Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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†Laboratório de Bioquímica de Vírus, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, RJ, Brazil
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*Laboratório de Bioenergética e Fisiologia Mitocondrial, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho 373 – CCS, Bl. D, ss13, 21941-902, RJ, Brazil
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Publisher: Portland Press Ltd
Received: April 18 2008
Revision Received: October 17 2008
Accepted: October 22 2008
Accepted Manuscript online: October 22 2008
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© The Authors Journal compilation © 2009 Biochemical Society
2009
Biochem J (2009) 417 (3): 717–726.
Revision Received:
October 17 2008
Accepted:
October 22 2008
Accepted Manuscript online:
October 22 2008
3-BrPA (3-bromopyruvate) is an alkylating agent with anti-tumoral activity on hepatocellular carcinoma. This compound inhibits cellular ATP production owing to its action on glycolysis and oxidative phosphorylation; however, the specific metabolic steps and mechanisms of 3-BrPA action in human hepatocellular carcinomas, particularly its effects on mitochondrial energetics, are poorly understood. In the present study it was found that incubation of HepG2 cells with a low concentration of 3-BrPA for a short period (150 μM for 30 min) significantly affected both glycolysis and mitochondrial respiratory functions. The activity of mitochondrial hexokinase was not inhibited by 150 μM 3-BrPA, but this concentration caused more than 70% inhibition of GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and 3-phosphoglycerate kinase activities. Additionally, 3-BrPA treatment significantly impaired lactate production by HepG2 cells, even when glucose was withdrawn from the incubation medium. Oxygen consumption of HepG2 cells supported by either pyruvate/malate or succinate was inhibited when cells were pre-incubated with 3-BrPA in glucose-free medium. On the other hand, when cells were pre-incubated in glucose-supplemented medium, oxygen consumption was affected only when succinate was used as the oxidizable substrate. An increase in oligomycin-independent respiration was observed in HepG2 cells treated with 3-BrPA only when incubated in glucose-supplemented medium, indicating that 3-BrPA induces mitochondrial proton leakage as well as blocking the electron transport system. The activity of succinate dehydrogenase was inhibited by 70% by 3-BrPA treatment. These results suggest that the combined action of 3-BrPA on succinate dehydrogenase and on glycolysis, inhibiting steps downstream of the phosphorylation of glucose, play an important role in HepG2 cell death.
© The Authors Journal compilation © 2009 Biochemical Society
2009
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