PGM3 regulates beta-catenin activity to promote colorectal cancer cell progression.

The hexosamine biosynthetic pathway (HBP) is connected to abnormal N- and O-linked protein glycosylation in cancer, which performs critical roles in tumorigenesis. However, the regulation mechanisms of HBP and its role in colorectal cancer (CRC) progression remain unexplained. This study analyzed the expression level of phosphoglucomutase 3 (PGM3), a key enzyme in HBP, and identified its function in CRC cell lines. Analysis of publicly available CRC microarray data determined that PGM3 is upregulated in CRC tumor tissues. Furthermore, functional experiments emphasized the significant roles of PGM3 in facilitating CRC cell proliferation and migration. Mechanistically, we demonstrated that the activity of ß-catenin in CRC was maintained by PGM3-mediated O-GlcNAcylation. PGM3 knockdown or inhibition of O-GlcNAc transferase decreased ß-catenin activity and the expression levels of its downstream targets. Collectively, our findings indicate that PGM3 exhibits tumor-promoting roles by elevating O-GlcNAcylation level and maintaining ß-catenin activity, and might serve as a prognostic biomarker and treatment target in CRC.

A novel ß-galactosidase from Klebsiella oxytoca ZJUH1705 for efficient production of galacto-oligosaccharides from lactose.

Galacto-oligosaccharides (GOS), which can be produced by enzymatic transgalactosylation of lactose with ß-galactosidases, have attracted much attention in recent years because of their prebiotic functions and wide uses in infant formula, infant foods, livestock feed, and pet food industries. In this study, a novel ß-galactosidase-producing Klebsiella oxytoca ZJUH1705, identified by its 16S rRNA sequence (GenBank accession no. MH981243), was isolated. Two ß-galactosidase genes, bga 1 encoding a 2058-bp fragment (GenBank accession no. MH986613) and bga 2 encoding a 3108-bp fragment (GenBank accession no. MN182756), were cloned from K. oxytoca ZJUH1705 and expressed in E. coli. The purified ß-gal 1 and ß-gal 2 had the specific activity of 217.56 U mg-1 and 57.9 U mg-1, respectively, at the optimal pH of 7.0. The reaction kinetic parameters Km, Vmax, and Kcat with oNPG as the substrate at 40 °C were 5.62 mM, 167.1 µmol mg-1 min-1, and 218.1 s-1, respectively, for ß-gal 1 and 3.91 mM, 14.6 µmol mg-1 min-1, and 28.9 s-1, respectively, for ß-gal 2. Although ß-gal 1 had a higher enzyme activity for lactose hydrolysis, only ß-gal 2 had a high transgalactosylation capacity. Using ß-gal 2 with the addition ratio of ~ 2.5 U g-1 lactose, a high GOS yield of 45.5 ± 2.3% (w/w-1) was obtained from lactose (40% w/w-1 or 480 g L-1) in a phosphate buffer (100 mM, pH 7.0) at 40 °C in 48 h. Thus, the ß-gal 2 from K. oxytoca ZJUH1705 would be a promising biocatalyst for GOS production from lactose.Key Points• A novel bacterial ß-galactosidase producer was isolated and identified.• ß-Galactosidases were cloned and expressed in heterologous strain and characterized.• Both enzymes have hydrolytic activity but only one have transglycosilation activity.• The developed process with ß-gal 2 could provide an alternative for GOS production.

Intracellular matrix Gla protein promotes tumor progression by activating JAK2/STAT5 signaling in gastric cancer.

Matrix Gla protein (MGP) has been widely reported as an extracellular matrix protein with abnormal expression in various types of cancer. However, the function of intracellular MGP in gastric cancer (GC) cells remains largely unknown. Here, we demonstrated aberrantly high expression of intracellular MGP in GC as compared to adjacent normal tissues by immunohistochemistry. Moreover, The Cancer Genome Atlas (TCGA) dataset analysis suggested a positive correlation between MGP overexpression and unfavorable prognosis. MGP silencing reduced cell proliferation, migration, invasion, and survival in GC cell lines. Gene set enrichment analysis of TCGA dataset indicated significant enrichment of the IL2-STAT5 signaling in MGP-high GC patients. Immunofluorescence staining and immunoprecipitation showed that MGP binds to p-STAT5 in the nuclei of GC cells. Furthermore, ChIP-qPCR and luciferase reporter assays indicated that MGP acts as a transcriptional co-activator through the enhancement of STAT5 binding to target gene promoters. Use of STAT5 inhibitor revealed that the oncogenic functions of intracellular MGP mainly depend on the JAK2/STAT5 signaling pathway. Taken together, our results indicate that intracellular MGP promotes proliferation and survival of GC cells by acting as a transcriptional co-activator of STAT5. The detected aberrant, high MGP expression in GC tissues highlights MGP as a potential new prognostic biomarker in patients with GC.

Cost-effective optimization of gellan gum production by Sphingomonas paucimobilis using corn steep liquor.

Gellan gum, produced by Sphingomonas paucimobilis, is increasingly used in food and pharmaceutical industries as stabilizing, emulsifying, texturing and gelling agents. However, its high production costs may limit its full commercial potential. Therefore, in this study, we investigated ways to reduce gellan gum production costs and improve yields. We first revealed corn steep liquor (CSL) as a cost-effective nutrient source that can improve gellan gum yields. We then systematically optimized culture conditions even further, and revealed that the addition of Triton X-100 surfactant and selected inorganic nitrogen sources improved gellan gum production. Under our optimized conditions (glucose 33.75 g/L, CSL 10 g/L, urea 2.5 g/L, MgSO4 1.08 g/L, KH2PO4 3.24 g/L, K2SO4 1 g/L and Triton X-100 0.75 g/L), we yielded a maximum concentration of 14.41 g/L, which was about 1.5-fold higher than non-optimized CSL-based medium. Our findings highlight the use of CSL as a cost effective and promising nutrient source for industrial production of gellan gum.

Biosynthesis of butyric acid by Clostridium tyrobutyricum.

Butyric acid (C3H7COOH) is an important chemical that is widely used in foodstuffs along with in the chemical and pharmaceutical industries. The bioproduction of butyric acid through large-scale fermentation has the potential to be more economical and efficient than petrochemical synthesis. In this paper, the metabolic pathways involved in the production of butyric acid from Clostridium tyrobutyricum using hexose and pentose as substrates are investigated, and approaches to enhance butyric acid production through genetic modification are discussed. Finally, bioreactor modifications (including fibrous bed bioreactor, inner disk-shaped matrix bioreactor, fibrous matrix packed in porous levitated sphere carriers), low-cost feedstocks, and special treatments (including continuous fermentation with cell recycling, extractive fermentation with solvent, using different artificial electron carriers) intended to improve the feasibility of commercial butyric acid bioproduction are summarized.