Reduced methylation of PFKFB3 in cancer cells shunts glucose towards the pentose phosphate pathway

Abstract

Haem oxygenase (HO)-1/carbon monoxide (CO) protects cancer cells from oxidative stress, but the gas-responsive signalling mechanisms remain unknown. Here we show using metabolomics that CO-sensitive methylation of PFKFB3, an enzyme producing fructose 2,6-bisphosphate (F-2,6-BP), serves as a switch to activate phosphofructokinase-1, a rate-limiting glycolytic enzyme. In human leukaemia U937 cells, PFKFB3 is asymmetrically di-methylated at R131 and R134 through modification by protein arginine methyltransferase 1. HO-1 induction or CO results in reduced methylation of PFKFB3 in varied cancer cells to suppress F-2,6-BP, shifting glucose utilization from glycolysis toward the pentose phosphate pathway. Loss of PFKFB3 methylation depends on the inhibitory effects of CO on haem-containing cystathionine β-synthase (CBS). CBS modulates remethylation metabolism, and increases NADPH to supply reduced glutathione, protecting cells from oxidative stress and anti-cancer reagents. Once the methylation of PFKFB3 is reduced, the protein undergoes polyubiquitination and is degraded in the proteasome. These results suggest that the CO/CBS-dependent regulation of PFKFB3 methylation determines directional glucose utilization to ensure resistance against oxidative stress for cancer cell survival.

Silver nanoparticles affect glucose metabolism in hepatoma cells through production of reactive oxygen species

“…Regarding PFKFB3, the protein levels of PFKFB3 were measured by Western blot and not based only on mRNA levels, suggesting alterations in protein degradation. 33 Since PFKFB3 can direct the glucose metabolic pathway to glycolysis or to PPP, based on its methylation status, 25 additional studies are needed to clarify the effect of PFKFB3 on glucose metabolism with AgNP treatment.…”

“…PFKFB3 catalyzes the conversion of fructose-6-phosphate to fructose-2,6-bisphosphate, which promotes glycolysis and suppresses gluconeogenesis, whereas PFKFB3 directs PPP when its arginine residues (R131/R134) are not methylated or its cysteine residue is glutathionylated. 22,24,25 Although the mRNA levels of PFKFB3 were not significantly altered by treatment with 5 nm AgNPs for 3 hours, its protein Figure 3 Transcript levels of hK2, PFKFB3, PePcK-c, and PePcK-M in hepatoma cells treated with agNPs. Notes: hepg2 (3×10 5 /ml, A, C, E, and G) and huh7 cells (2×10 5 /ml, B, D, F, and H) were treated with the indicated concentrations of 5 or 100 nm agNPs for 3 hours.…”

Targeting Oxygen-Sensing Prolyl Hydroxylase for Metformin-Associated Lactic Acidosis Treatment

“…Photomicrographs were obtained using a BZ-9000 fluorescence microscope (Keyence, Osaka, Japan) at a magnification of ϫ20. Matrix-assisted laser desorption ionization-imaging mass spectrometry (MALDI-IMS) analysis of 2,8-dihydroxyadenine (m/z 168.05) in the kidneys of mice receiving a normal diet or an adenine-containing diet was performed in the positive ion mode using an atmospheric pressure MALDI-quadrupole ion trap time of flight mass spectrometer (MALDI-QIT-TOF-MS) (Shimadzu, Kyoto, Japan) as described previously (6,42,43).…”

Acquired platinum resistance involves epithelial to mesenchymal transition through ubiquitin ligase FBXO32 dysregulation

“…First, the development of acquired platinum resistance involved EMT, resulting in tumor aggressiveness with motile function of cancer cells. Second, from global gene expression profiles using 2 types of PR cells, we identified what we believe to be a novel role for the ubiquitin ligase FBXO32 as a negative regulator of the EMT after acquisition of platinum resistance, providing an additional mechanism distinct from those causing platinum resistance of cancer (35,36).…”