Abstract Many cancer cells display enhanced glycolysis and suppressed mitochondrial metabolism. This phenomenon, known as the Warburg effect, is critical for tumor development. However, how cancer cells coordinate glucose metabolism through glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle is largely unknown. We demonstrate here that phosphoglycerate kinase 1 (PGK1), the first ATP-producing enzyme in glycolysis, is reversibly and dynamically modified with O-linked N-acetylglucosamine (O-GlcNAc) at threonine 255 (T255). O-GlcNAcylation activates PGK1 activity to enhance lactate production, and simultaneously induces PGK1 translocation into mitochondria. Inside mitochondria, PGK1 acts as a kinase to inhibit pyruvate dehydrogenase (PDH) complex to reduce oxidative phosphorylation. Blocking T255 O-GlcNAcylation of PGK1 decreases colon cancer cell proliferation, suppresses glycolysis, enhances the TCA cycle, and inhibits tumor growth in xenograft models. Furthermore, PGK1 O-GlcNAcylation levels are elevated in human colon cancers. This study highlights O-GlcNAcylation as an important signal for coordinating glycolysis and the TCA cycle to promote tumorigenesis.
Introduction: Accumulated studies have suggested that hepatitis C virus (HCV) infection is one of the leading causes for hepatocellular carcinoma (HCC). However, the mechanisms underlying the effect of HCV on the occurrence of HCC is still poorly understood. Methods: HCV infection datasets (GSE82177 and GSE17856) and HCC datasets (TCGA-LIHC (The Cancer Genome Atlas Liver Hepatocellular Carcinoma) and GSE89377) were downloaded from Gene Expression Omnibus (GEO) or TCGA for analysis. The common differentially expressed genes (DEGs) in the above four datasets were identified by R software. The expression of Ubiquitin D (UBD) in HCV infected HepG2 cells was detected by RT-qPCR and western blot, respectively. The interaction between NS3 and p53 was detected by Co-Immunoprecipitation. The influence of UBD on the proliferation and migration ability of HepG2 cells was evaluated by CCK-8 and wound healing assay, respectively. Results: UBD was upregulated in both HCV infected samples and HCC samples. HCV NS3 interacted with p53 and inhibited its expression. HCV NS3 induced UBD promoted the proliferation and migration of HepG2 cells. Conclusion: Our results suggest that HCV NS3 induced UBD is positively correlated with the development of HCV-related HCC during HCV infection. Targeting UBD could be a potential strategy for preventing and treating HCV-induced HCC.
Wilson's disease (WD) is an autosomal recessive inherited disorder caused by mutations in the ATPase Cu2+ transporting beta polypeptide gene (ATP7B). The detailed metabolism of copper-induced pathology in WD is still unknown. Gene mutations as well as the possible pathways involved in the ATP7B deficiency were documented. The ATP7B gene was analyzed for mutations in 18 Chinese Han families with WD by direct sequencing. Cell viability and apoptosis analysis of ATP7B small interfering RNA (siRNA)-treated human liver carcinoma (HepG2) cells were measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and Hoechst 33342 staining. Finally, the expression of B-cell CLL/lymphoma 2 (BCL2), BCL2-associated X protein (BAX), sterol regulatory element binding protein 1 (SREBP1), and minichromosome maintenance protein 7 (MCM7) of ATP7B siRNA-treated cells were tested by real-time polymerase chain reaction (real-time PCR) and Western blot analysis. Twenty different mutations including four novel mutations (p.Val145Phe, p.Glu388X, p.Thr498Ser and p.Gly837X) in the ATP7B gene were identified in our families. Haplotype analysis revealed that founder effects for four mutations (p.Arg778Leu, p.Pro992Leu, p.Ile1148Thr and p.Ala1295Val) existed in these families. Transfection of HepG2 cells with ATP7B siRNA resulted in decreased mRNA expression by 86.3%, 93.1% and 90.8%, and decreased protein levels by 58.5%, 85.5% and 82.1% at 24, 48 and 72 hours, respectively (All P<0.01). In vitro study revealed that the apoptotic, cell cycle and lipid metabolism pathway may be involved in the mechanism of WD. Our results revealed that the genetic cause of 18 Chinese families with WD and ATP7B deficiency-induce apoptosis may result from imbalance in cell cycle and lipid metabolism pathway.
Background The SCN11A gene encodes the α-subunit of the Nav1. 9 channel, which is a regulator of primary sensory neuron excitability. Nav1.9 channels play a key role in somatalgia. Humans with the gain-of-function mutation R222S in SCN11A exhibit familial episodic pain. As already known, R222S knock-in mice carrying a mutation orthologous to the human R222S variant demonstrate somatic hyperalgesia. This study investigated whether Scn 11 a R222S/R222S mice developed visceral hyperalgesia and intestinal dysmotility. Methods We generated Scn 11 a R222S/R222S mice using the CRISPR/Cas9 system. The somatic pain threshold in Scn 11 a R222S/R222S mice was assessed by Hargreaves' test and formalin test. The excitability of dorsal root ganglia (DRG) neurons was assessed by whole-cell patch-clamp recording. Visceralgia was tested using the abdominal withdrawal reflex (AWR), acetic acid-induced writhing, and formalin-induced visceral nociception tests. Intestinal motility was detected by a mechanical recording of the intestinal segment and a carbon powder propelling test. The excitability of the enteric nervous system (ENS) could influence gut neurotransmitters. Gut neurotransmitters participate in regulating intestinal motility and secretory function. Therefore, vasoactive intestinal peptide (VIP) and substance P (SP) were measured in intestinal tissues. Results The R222S mutation induced hyperexcitability of dorsal root ganglion neurons in Scn 11 a R222S/R222S mice. Scn 11 a R222S/R222S mice exhibited somatic hyperalgesia. In addition, Scn 11 a R222S/R222S mice showed lower visceralgia thresholds and slowed intestinal movements when compared with wild-type controls. Moreover, Scn 11 a R222S/R222S mice had lower SP and VIP concentrations in intestinal tissues. Conclusions These results indicated that Scn 11 a R222S/R222S mice showed visceral hyperalgesia and intestinal dysmotility.
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