Lactic acidosis caused by repressed lactate dehydrogenase subunit B expression down-regulates mitochondrial oxidative phosphorylation via the pyruvate dehydrogenase (PDH)–PDH kinase axis

Sun, Hao; Lee, Young-Kyoung; Park, Imkyong; Kwon, So Mee; Min, Seungwook; Yoon, Gyesoon

doi:10.1074/jbc.ra118.006095

Cited by 32 publications

(23 citation statements)

References 53 publications

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“…Lactic acid and pyruvate regulate the energy producing function of mitochondria [61]. Additionally, in human hepatoma cells, inhibition of LDHB causes lactic acidosis, and downregulation of mitochondrial phosphorylation through the pyruvate dehydrogenase (PDH)-PDK (pyruvate dehydrogenase kinase) axis, thereby promoting liver cancer progression [62]. Moreover, inhibition of LDHB enhances CLDN1 (claudin 1)-mediated hepatoma cell invasiveness via mitochondrial defects [63].…”

Section: Discussionmentioning

confidence: 99%

LDHB inhibition induces mitophagy and facilitates the progression of CSFV infection

Fan

Zhao

et al. 2020

Autophagy

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Cellular metabolism caters to the energy and metabolite needs of cells. Although the role of the terminal metabolic enzyme LDHB (lactate dehydrogenase B) in the glycolysis pathway has been widely studied in cancer cells, its role in viral infection is relatively unknown. In this study, we found that CSFV (classical swine fever virus) infection reduces pyruvate levels while promotes lactate release in pigs and in PK-15 cells. Moreover, using a yeast two-hybrid screening system, we identified LDHB as a novel interacting partner of CSFV non-structural protein NS3. These results were confirmed via co-immunoprecipitation, glutathione S-transferase and confocal assays. Furthermore, knockdown of LDHB via interfering RNA induced mitochondrial fission and mitophagy, as detected reduced mitochondrial mass. Upon inhibition of LDHB, expression of the mitophagy proteins TOMM20 and VDAC1 decreased and the ubiquitination of MFN2, a mitochondrial fusion mediator, was promoted. In addition, a sensitive dual fluorescence reporter (mito-mRFP-EGFP) was utilized to analyze the delivery of autophagosomes to lysosomes in LDHB inhibition cells. Furthermore, LDHB inhibition promoted NFKB signaling, which was regulated by mitophagy; meanwhile, infection with CSFV negated these NFKB anti-viral responses. Inhibition of LDHB also inhibited apoptosis, providing an environment conducive to persistent viral infection. Finally, we demonstrated that LDHB inhibition promoted CSFV growth via mitophagy, whereas its overexpression decreased CSFV replication. Our data revealed a novel mechanism through which LDHB, a metabolic enzyme, mediates CSFV infection, and provides new avenues for the development of anti-viral strategies.

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Section: Discussionmentioning

confidence: 99%

LDHB inhibition induces mitophagy and facilitates the progression of CSFV infection

Fan

Zhao

et al. 2020

Autophagy

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“…Pyruvate dehydrogenase (PDH) is a component enzyme of the pyruvate dehydrogenase complex, which catalyzes conversion of pyruvate to acetyl-CoA, the entry substrate for the TCA cycle, rather than converting pyruvate into lactate (35). De-phosphorylation of speci c serine residues of the E1-alpha subunit of PDH, Ser300 (pPDH S300), Ser232 (pPDH S232), or Ser239 (pPDH S239), activates the conversion of pyruvate to acetyl CoA, whereas phosphorylation inactivates the enzyme, resulting in increased conversion into lactate.…”

Section: Spheroid Invasion Assaymentioning

confidence: 99%

Metabolic characterization of aggressive breast cancer cells exhibiting invasive phenotype: Impact of non-cytotoxic doses of 2-DG on diminishing invasiveness

Fujita

Imadome

Somasundaram

et al. 2020

Preprint

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Abstract BackgroundMetabolic reprogramming is being recognized as a fundamental hallmark of cancer, and efforts to identify drugs that can target cancer metabolism are underway. In this study, we used human breast cancer (BC) cell lines and established their invading phenotype (INV) collected from transwell inserts to compare metabolome differences and evaluate prognostic significance of the metabolome in aggressive BC invasiveness.MethodsThe invasiveness of seven human BC cell lines were compared using the transwell invasion assay. Among these, INV was collected from SUM149, which exhibited the highest invasiveness. Levels of metabolites in INV were compared with those of whole cultured SUM149 cells (WCC) using CE-TOFMS. The impact of glycolysis in INV was determined by glucose uptake assay using fluorescent derivative of glucose (2-NBDG), and significance of glycolysis, or tricarboxylic acid (TCA) and electron transport chain (ETC) in the invasive process were further determined in aggressive BC cell lines, SUM149, MDA-MB-231, HCC1937, using invasion assays in the presence or absence of inhibitors of glycolysis, TCA cycle or ETC.ResultsSUM149 INV sub-population exhibited a persistent hyperinvasive phenotype. INV were hyper-glycolytic with increased glucose (2-NBDG) uptake; diminished glucose-6-phosphate (G6P) levels but elevated pyruvate and lactate, along with higher expression of phosphorylated-pyruvate dehydrogenase (pPDH) compared to WCC. Notably, inhibiting of glycolysis with lower doses of 2-DG (1 mM), non-cytotoxic to MDA-MB-231 and HCC1937, was effective in diminishing invasiveness of aggressive BC cell lines. In contrast, 3-Nitropropionic acid (3-NA), an inhibitor of succinate dehydrogenase, the enzyme that oxidizes succinate to fumarate in TCA cycle, and functions as complex II of ETC, had no significant effect on their invasiveness, although levels of TCA metabolites or detection of mitochondrial membrane potential with JC-1 staining, indicated that INV cells originally had functional TCA cycles and membrane potential.ConclusionsHyper-glycolytic phenotype of invading cells caters to rapid energy production required for invasion while TCA cycle/ETC cater to cellular energy needs for sustenance in aggressive BC. Lower, non-cytotoxic doses of 2-DG can hamper invasion and can potentially be used as an adjuvant with other anti-cancer therapies without the usual side-effects associated with cytotoxic doses.

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“…Pyruvate dehydrogenase (PDH) is a component enzyme of the pyruvate dehydrogenase complex, which catalyzes conversion of pyruvate to acetyl-CoA, the entry substrate for the TCA cycle, rather than converting pyruvate into lactate (36). De-phosphorylation of speci c serine residues of the E1-alpha subunit of PDH, Ser300 (pPDH S300), Ser232 (pPDH S232), or Ser239 (pPDH S239), activates the conversion of pyruvate to acetyl CoA, whereas phosphorylation inactivates the enzyme, resulting in increased conversion into lactate.…”

Section: Discussionmentioning

confidence: 99%

Metabolic characterization of aggressive breast cancer cells exhibiting invasive phenotype: Impact of non-cytotoxic doses of 2-DG on diminishing invasiveness

Fujita

Imadome

Somasundaram

et al. 2020

Preprint

View full text Add to dashboard Cite

BackgroundMetabolic reprogramming is being recognized as a fundamental hallmark of cancer, and efforts to identify drugs that can target cancer metabolism are underway. In this study, we used human breast cancer (BC) cell lines and established their invading phenotype (INV) collected from transwell inserts to compare metabolome differences and evaluate prognostic significance of the metabolome in aggressive BC invasiveness. MethodsThe invasiveness of seven human BC cell lines were compared using the transwell invasion assay. Among these, INV was collected from SUM149, which exhibited the highest invasiveness. Levels of metabolites in INV were compared with those of whole cultured SUM149 cells (WCC) using CE-TOFMS. The impact of glycolysis in INV was determined by glucose uptake assay using fluorescent derivative of glucose (2-NBDG), and significance of glycolysis, or tricarboxylic acid cycle (TCA) and electron transport chain (ETC) in the invasive process were further determined in aggressive BC cell lines, SUM149, MDA-MB-231, HCC1937, using invasion assays in the presence or absence of inhibitors of glycolysis, TCA cycle or ETC. ResultsSUM149 INV sub-population exhibited a persistent hyperinvasive phenotype. INV were hyper-glycolytic with increased glucose (2-NBDG) uptake; diminished glucose-6-phosphate (G6P) levels but elevated pyruvate and lactate, along with higher expression of phosphorylated-pyruvate dehydrogenase (pPDH) compared to WCC. Notably, inhibiting of glycolysis with lower doses of 2-DG (1 mM), non-cytotoxic to MDA-MB-231 and HCC1937, was effective in diminishing invasiveness of aggressive BC cell lines. In contrast, 3-Nitropropionic acid (3-NA), an inhibitor of succinate dehydrogenase, the enzyme that oxidizes succinate to fumarate in TCA cycle, and functions as complex II of ETC, had no significant effect on their invasiveness, although levels of TCA metabolites or detection of mitochondrial membrane potential with JC-1 staining, indicated that INV cells originally had functional TCA cycles and membrane potential. ConclusionsHyper-glycolytic phenotype of invading cells caters to rapid energy production required for invasion while TCA cycle/ETC cater to cellular energy needs for sustenance in aggressive BC. Lower, non-cytotoxic doses of 2-DG can hamper invasion and can potentially be used as an adjuvant with other anti-cancer therapies without the usual side-effects associated with cytotoxic doses.

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Lactic acidosis caused by repressed lactate dehydrogenase subunit B expression down-regulates mitochondrial oxidative phosphorylation via the pyruvate dehydrogenase (PDH)–PDH kinase axis

Cited by 32 publications

References 53 publications

LDHB inhibition induces mitophagy and facilitates the progression of CSFV infection

LDHB inhibition induces mitophagy and facilitates the progression of CSFV infection

Metabolic characterization of aggressive breast cancer cells exhibiting invasive phenotype: Impact of non-cytotoxic doses of 2-DG on diminishing invasiveness

Metabolic characterization of aggressive breast cancer cells exhibiting invasive phenotype: Impact of non-cytotoxic doses of 2-DG on diminishing invasiveness

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