Aberrant Fucosylation of Saliva Glycoprotein Defining Lung Adenocarcinomas Malignancy

Aberrant glycosylation is a hallmark of cancer found during tumorigenesis and tumor progression. Lung cancer induced by oncogene mutations has been detected in the patient's saliva, and saliva glycosylation has been altered. Saliva contains highly glycosylated glycoproteins, the characteristics of which may be related to various diseases. Therefore, elucidating cancer-specific glycosylation in the saliva of healthy, non-cancer, and cancer patients can reveal whether tumor glycosylation has unique characteristics for early diagnosis. In this work, we used a solid-phase chemoenzymatic method to study the glycosylation of saliva glycoproteins in clinical specimens. The results showed that the alpha1,6-core fucosylation of glycoproteins in cancer patients was significant increased. The fucosylation of alpha1,2 or alpha1,3 is also increased in cancer patients. We further analyzed the expression of fucosyltransferases responsible for alpha1,2, alpha1,3, alpha1,6 fucosylation. The fucosylation of the saliva of cancer patients is drastically different from that of non-cancer or health controls. These results indicate that the glycoform of saliva fucosylation distinguishes lung cancer from other diseases, and this feature has the potential to diagnose lung adenocarcinoma.

Overexpression of fucosyltransferase 8 reverses the inhibitory effect of high-dose dexamethasone on osteogenic response of MC3T3-E1 preosteoblasts

Background Core fucosylation catalyzed by FUT8 is essential for TGF-β binding to TGF-β receptors. Methods Indirect TGF-β1 binding assay was used to evaluate the ability of TGF-β1 to bind to TGFBRs, Alizarin red and alkaline phosphatase staining were used to detect osteogenic differentiation and mineralization ability , western blot and quantitative RT-PCR were used to measure the differential expression of osteogenesis-related proteins and genes. Plasmid-mediated gain-of-function study. The scale of core fucosylation modification was detected by Lectin-blot and LCA laser confocal. Results Our results showed that compared with vehicle treatment, high-dose (10−6 and 10−5 M) dexamethasone significantly inhibited cell proliferation, osteogenic differentiation, and FUT8 mRNA expression while promoting mRNA expression of adipogenesis-related genes in MC3T3-E1 cells, suggesting that downregulation of FUT8 is involved in the inhibitory effect of high-dose dexamethasone on osteogenesis. Overexpression of FUT8 significantly promoted osteogenic differentiation and activated TGF-β/Smad signaling in MC3T3-E1 cells in the presence of high-dose dexamethasone, suggesting that FUT8 reverses the inhibitory effect of high-dose dexamethasone on osteogenesis. In addition, lectin fluorescent staining and blotting showed that overexpression of FUT8 significantly reversed the inhibitory effects of high-dose dexamethasone on core fucosylation of TGFBR1 and TGFBR2. Furthermore, indirect TGF-β1 binding assay showed that overexpression of FUT8 remarkably promoted TGF-β1 binding to TGFBRs in MC3T3-E1 cells in the presence of high-dose dexamethasone. Conclusions Taken together, these results suggest that overexpression of FUT8 facilitates counteracting the inhibitory effect of dexamethasone on TGF-β signaling and osteogenesis.

Alpha-(1,6)-fucosyltransferase (FUT8) affects the survival strategy of osteosarcoma by remodeling TNF/NF-κB2 signaling

Glycosylation is an important modification of membrane proteins that results in functional changes in many cellular activities, from cell-cell recognition to regulatory signaling. Fucosyltransferase 8 (FUT8) is the sole enzyme responsible for core fucosylation, and aberrant fucosylation by dysregulated expression of fucosyltransferases is responsible for the growth of various types of carcinomas. However, the function of FUT8 in the progress of osteosarcoma (OS) has not been reported. In this study, we found that FUT8 is expressed at lower levels in patients with OS and in human OS cell lines such as MNNG/HOS, U2OS, and 143B, suggesting that attenuated expression of FUT8 is involved in the growth and progression of OS. Mechanistically, FUT8 affects the survival strategy of OS by modifying core-fucosylation levels of TNF receptors (TNFRs). Lower fucosylation of TNFRs activates the non-canonical NF-κB signaling pathway, and in turn, decreases mitochondria-dependent apoptosis in OS cells. Together, our results point to FUT8 being a negative regulator of OS that enhances OS-cell apoptosis and suggests a novel therapeutic strategy for treating OS.

Analysis of site and structure specific core fucosylation in liver cirrhosis using exoglycosidase-assisted data-independent LC-MS/MS

Carbohydrates form one of the major groups of biological macromolecules in living organisms. Many biological processes including protein folding, stability, immune response, and receptor activation are regulated by glycosylation. Fucosylation of proteins regulates such processes and is associated with various diseases including autoimmunity and cancer. Mass spectrometry efficiently identifies structures of fucosylated glycans or sites of core fucosylated N-glycopeptides but quantification of the glycopeptides remains less explored. We performed experiments that facilitate quantitative analysis of the core fucosylation of proteins with partial structural resolution of the glycans and we present results of the mass spectrometric SWATH-type DIA analysis of relative abundances of the core fucosylated glycoforms of 45 glycopeptides to their nonfucosylated glycoforms derived from 18 serum proteins in liver disease of different etiologies. Our results show that a combination of soft fragmentation with exoglycosidases is efficient at the assignment and quantification of the core fucosylated N-glycoforms at specific sites of protein attachment. In addition, our results show that disease-associated changes in core fucosylation are peptide-dependent and further differ by branching of the core fucosylated glycans. Further studies are needed to verify whether tri- and tetra-antennary core fucosylated glycopeptides could be used as markers of liver disease progression.

Lactobacillus spp. create a protective micro-ecological environment through regulating the core fucosylation of vaginal epithelial cells against cervical cancer

Vaginal dysbiosis often occurs in patients with cervical cancer. The fucosylation of mucosal epithelial cells is closely related to microbial colonization, and play an important role in protecting the vaginal mucosal epithelial cells. However, no reports on the relationship between vaginal dysbiosis and abnormal mucosal epithelial cell fucosylation, and their roles in the occurrence and development of cervical cancer are unavailable. Here we report that core fucosylation levels were significantly lower in the serum, exfoliated cervical cells and tumor tissue of cervical cancer patients. Core fucosyltransferase gene (Fut8) knockout promoted the proliferation and migration of cervical cancer cells. In patients with cervical cancer, the vaginal dysbiosis, and the abundance of Lactobacillus, especially L. iners, was significantly reduced. Meanwhile, the abundance of L.iners was positively correlated with core fucosylation levels. The L. iners metabolite lactate can activate the Wnt pathway through the lactate-Gpr81 complex, which increases the level of core fucosylation in epidermal cells, inhibiting the proliferation and migration of cervical cancer cells, and have application prospects in regulating the vaginal microecology and preventing cervical cancer.

Quantitative Glycoproteomics Analysis Identifies Novel FUT8 Targets and Signaling Networks Critical for Breast Cancer Cell Invasiveness

BackgroundWe recently showed that fucosyltransferase 8 (FUT8)-mediated core fucosylation of transforming growth factor-β receptor enhances its signaling and promotes breast cancer invasion and metastasis. However, the complete FUT8 target glycoproteins and their downstream signaling networks critical for breast cancer progression remain largely unknown.MethodWe performed quantitative glycoproteomics with two highly invasive breast cancer cell lines to unravel a comprehensive list of core-fucosylated glycoproteins by comparison to parental wild-type and FUT8-knockout counterpart cells. In addition, Ingenuity Pathway Analysis (IPA) was performed to highlight the most enriched biological functions and signaling pathways mediated by FUT8 targets. Novel FUT8 target glycoproteins with biological interest were functionally studied and validated by using LCA (Lens culinaris agglutinin) blotting and LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis.ResultsLoss-of-function studies demonstrated that FUT8 knockout suppressed the invasiveness of highly aggressive breast carcinoma cells. Quantitative glycoproteomics identified 140 common target glycoproteins. Ingenuity Pathway Analysis (IPA) of these target proteins gave a global and novel perspective on signaling networks essential for breast cancer cell migration and invasion. In addition, we showed that core fucosylation of integrin αvβ5 or IL6ST is crucial for breast cancer cell adhesion to vitronectin or enhanced cellular signaling to interleukin 6 and oncostatin M, two cytokines implicated in the breast cancer epithelial–mesenchymal transition and metastasis.ConclusionsOur report reveals a comprehensive list of core-fucosylated target proteins and provides novel insights into signaling networks crucial for breast cancer progression. These findings will assist in deciphering the complex molecular mechanisms and developing diagnostic or therapeutic approaches targeting these signaling pathways in breast cancer metastasis.

Glycosylation: Rising Potential for Prostate Cancer Evaluation

Prostate cancer is the second most commonly diagnosed cancer among men. Alterations in protein glycosylation are confirmed to be a reliable hallmark of cancer. Prostate-specific antigen is the biomarker that is used most frequently for prostate cancer detection, although its lack of sensitivity and specificity results in many unnecessary biopsies. A wide range of glycosylation alterations in prostate cancer cells, including increased sialylation and fucosylation, can modify protein function and play a crucial role in many important biological processes in cancer, including cell signalling, adhesion, migration, and cellular metabolism. In this review, we summarize studies evaluating the prostate cancer associated glycosylation related alterations in sialylation, mainly α2,3-sialylation, core fucosylation, branched N-glycans, LacdiNAc group and presence of truncated O-glycans (sTn, sT antigen). Finally, we discuss the great potential to make use of glycans as diagnostic and prognostic biomarkers for prostate cancer.