Leukemia cells demonstrate a different metabolic perturbation provoked by 2-deoxyglucose

Abstract

Abstract. The shift in energy metabolism from oxidative phosphorylation to glycolysis can serve as a target for the inhibition of cancer growth. Here, we examined the metabolic changes induced by 2-deoxyglucose (2-DG), a glycolysis inhibitor, in leukemia cells by metabolome analysis. NB4 cells mainly utilized glucose as an energy source by glycolysis and oxidative phosphorylation in mitochondria, since metabolites in the glycolytic pathway and in the tricarboxylic acid (TCA) cycle were significantly decreased by 2-DG. In THP-1 cells, metabolites in the TCA cycle were not decreased to the same extent by 2-DG as in NB4 cells, which indicates that THP-1 utilizes energy sources other than glucose. TCA cycle metabolites in THP-1 cells may be derived from acetyl-CoA by fatty acid β-oxidation, which was supported by abundant detection of carnitine and acetylcarnitine in THP-1 cells. 2-DG treatment increased the levels of pentose phosphate pathway (PPP) metabolites and augmented the generation of NADPH by glucose-6-phosphate dehydrogenase. An increase in NADPH and upregulation of glutathione synthetase expression resulted in the increase in the reduced form of glutathione by 2-DG in NB4 cells. We demonstrated that a combination of 2-DG and inhibition of PPP by dehydroepiandrosterone (DHEA) effectively suppressed the growth of NB4 cells. The replenishment of the TCA cycle by fatty acid oxidation by carnitine palmitoyltransferase in THP-1 cells, treated by 2-DG, might be regulated by AMPK, as the combination of 2-DG and inhibition of AMPK by compound C potently suppressed the growth of THP-1 cells. Although 2-DG has been effective in preclinical and clinical studies, this treatment has not been fully explored due to concerns related to potential toxicities such as brain toxicity at high doses. We demonstrated that a combination of 2-DG and DHEA or compound C at a relatively low concentration effectively inhibits the growth of NB4 and THP-1 cells, respectively. These observations may aid in the identification of appropriate combinations of metabolic inhibitors at low concentrations which do not cause toxicities. IntroductionOne of the fundamental changes that occurs in cancer cells is the shift in energy metabolism from the generation of ATP from oxidative phosphorylation to glycolysis even in the presence of sufficient oxygen (Warburg effect) (1,2). Several agents that specifically inhibit glycolytic metabolism, such as 2-deoxy-D-glucose (2-DG), have been used as effective anticancer agents in cellular systems and in animal models (3,4). Similar to glucose, 2-DG is taken up through glucose transporters (GLUTs) and is phosphorylated by hexokinase (HK) to form 2-DG-6-phosphate (2-DG-6-P). 2-DG-6-P accumulates within the cell and is not metabolized further. Then, 2-DG-6-P induces cell growth arrest and cell death by inhibiting 2 glycolytic enzymes, HK and phosphoglucose isomerase (PGI) (5,6).Although 2-DG has been undergoing clinical trials for treatment of several types of cancers, its efficacy as a monotherapy is limited b...

Signalling mechanisms that regulate metabolic profile and autophagy of acute myeloid leukaemia cells

“…Regarding the energetic metabolism, our results categorize the different AML cells with NB‐4 as a glycolytic cell line, as reported in some studies,49, 50, 51 HL‐60 cells mainly dependent on glycolysis12 and KG‐1 cells displaying a predominant OXPHOS metabolism. These results not only showed that 2 closely related cell lines, NB‐4 and HL‐60, present different energetic metabolism, but also that KG‐1 cells are mainly OXPHOS dependent, as reflected by the carbon flux through mitochondria for lactate production (Figure 1).…”

2‐Deoxy‐d‐glucose enhances tonic inhibition through the neurosteroid‐mediated activation of extrasynaptic GABAA receptors

“…2‐DG is taken up by glucose transporters (mostly GLUT1/3) and subsequently phosphorylated in 2‐deoxy‐ d ‐glucose‐6‐phosphate (2‐DG‐6P), which cannot be converted into fructose‐6P by phosphoglucose isomerase . This leads to a reduction in glucose metabolism through the glycolytic pathway and to the alternative shunting through the PPP associated with increased NADPH levels . Because NADPH is the cofactor of 5α‐R, the rate‐limiting enzyme of neurosteroid biosynthesis, its activation may increase the levels of neurosteroids that, in turn, directly activate extrasynaptic GABA A receptors, as reported previously …”

“…10 This leads to a reduction in glucose metabolism through the glycolytic pathway and to the alternative shunting through the PPP associated with increased NADPH levels. [11][12][13] Because NADPH is the cofactor of 5a-R, the rate-limiting enzyme of neurosteroid biosynthesis, its activation may increase the levels of neurosteroids that, in turn, directly activate extrasynaptic GABA A receptors, as reported previously. 22 Thus, we investigated whether the increase in the GABA A receptor-mediated outward current induced by 2-DG depends on the enhanced neurosteroid biosynthesis due to an increased availability of NADPH.…”

“…2‐DG inhibits glycolysis by competing with glucose for glucose‐6‐phosphate isomerase and decreasing glucose uptake . 2‐DG is accumulated in the cell as 2‐deoxyglucose‐6‐phosphate and, in this form, can only be metabolized in the pentose phosphate pathway (PPP) with a resulting increase in reduced nicotinamide‐adenine dinucleotide phosphate (NADPH) levels …”

“…10 2-DG is accumulated in the cell as 2-deoxyglucose-6-phosphate and, in this form, can only be metabolized in the pentose phosphate pathway (PPP) with a resulting increase in reduced nicotinamide-adenine dinucleotide phosphate (NADPH) levels. [11][12][13][14] Although the antiseizure properties of 2-DG have been demonstrated both in vitro and in vivo, 7,9 its mechanism of action is still unclear. It has been reported that 2-DG acts primarily via ATP-sensitive potassium (K ATP ) channels, metabolic sensors that couple neuronal excitability to ATP levels.…”