FUT8 and Protein Core Fucosylation in Tumours: From Diagnosis to Treatment

Lectin-modified drug delivery systems - Recent applications in the oncology field

Chemotherapy with cytotoxic drugs remains the core treatment for cancer but, due to the difficulty to find general and usable biochemical differences between cancer cells and normal cells, many of these drugs are associated with lack of specificity, resulting in side effects and collateral cytotoxicity that impair patients' adherence to therapy. Novel cancer treatments in which the cytotoxic effect is maximized while adverse effects are reduced can be implemented by developing targeted therapies that exploit the specific features of cancer cells, such as the typical expression of aberrant glycans. Modification of drug delivery systems with lectins is one of the strategies to implement targeted chemotherapies, as lectins are able to specifically recognize and bind to cancer-associated glycans expressed at the surface of cancer cells, guiding the drug treatment towards these cells and not affecting healthy ones. In this paper, recent advances on the development of lectin-modified drug delivery systems for targeted cancer treatments are thoroughly reviewed, with a focus on their properties and performance in diverse applications, as well as their main advantages and limitations. The synthesis and analytical characterization of the cited lectin-modified drug delivery systems is also briefly described. A comparison with free-drug treatments and with antibody-modified drug delivery systems is presented, emphasizing the advantages of lectin-modified drug delivery systems. Main constraints and potential challenges of lectin-modified drug delivery systems, including key difficulties for clinical translation of these systems, and the required developments in this area, are also signalled.

Neuroglycome alterations of hippocampus and prefrontal cortex of juvenile rats chronically exposed to glyphosate-based herbicide

Introduction

Glyphosate-based herbicides (GBHs) have been shown to have significant neurotoxic effects, affecting both the structure and function of the brain, and potentially contributing to the development of neurodegenerative disorders. Despite the known importance of glycosylation in disease progression, the glycome profile of systems exposed to GBH has not been thoroughly investigated.

Methods

In this study, we conducted a comprehensive glycomic profiling using LC-MS/MS, on the hippocampus and prefrontal cortex (PFC) of juvenile rats exposed to GBH orally, aiming to identify glyco-signature aberrations after herbicide exposure.

Results

We observed changes in the glycome profile, particularly in fucosylated, high mannose, and sialofucosylated N-glycans, which may be triggered by GBH exposure. Moreover, we found major significant differences in the N-glycan profiles between the GBH-exposed group and the control group when analyzing each gender independently, in contrast to the analysis that included both genders. Notably, gender differences in the behavioral test of object recognition showed a decreased performance in female animals exposed to GBH compared to controls (p < 0.05), while normal behavior was recorded in GBH-exposed male rats (p > 0.05).

Conclusion

These findings suggest that glycans may play a role in the neurotoxic effect caused by GBH. The result suggests that gender variation may influence the response to GBH exposure, with potential implications for disease progression and specifically the neurotoxic effects of GBHs. Understanding these gender-specific responses could enhance knowledge of the mechanisms underlying GBH-induced toxicity and its impact on brain health. Overall, our study represents the first detailed analysis of N-glycome profiles in the hippocampus and PFC of rats chronically exposed to GBH. The observed alterations in the expression of N-glycan structures suggest a potential neurotoxic effect associated with chronic GBH exposure, highlighting the importance of further research in this area.

The role of protein post-translational modifications in prostate cancer

Involving addition of chemical groups or protein units to specific residues of the target protein, post-translational modifications (PTMs) alter the charge, hydrophobicity, and conformation of a protein, which in turn influences protein function, protein-protein interaction, and protein aggregation. These alterations, which include phosphorylation, glycosylation, ubiquitination, methylation, acetylation, lipidation, and lactylation, are significant biological events in the development of cancer, and play vital roles in numerous biological processes. The processes behind essential functions, the screening of clinical illness signs, and the identification of therapeutic targets all depend heavily on further research into the PTMs. This review outlines the influence of several PTM types on prostate cancer (PCa) diagnosis, therapy, and prognosis in an effort to shed fresh light on the molecular causes and progression of the disease.

Repaglinide restrains HCC development and progression by targeting FOXO3/lumican/p53 axis

PURPOSE

The recent focus on the roles of N-linked glycoproteins in carcinogenesis across various malignancies has prompted our exploration of aberrantly expressed glycoproteins responsible for HCC progression and potential therapeutic strategy.

METHODS

Mass spectrometry was applied to initially identify abnormally expressed glycoproteins in HCC, which was further assessed by immunohistochemistry (IHC) staining. The role of selected glycoprotein on HCC development and underlying mechanism was systematically investigated by colony formation, mouse xenograft, RNA-sequencing and western blot assays, etc. Chromatin immunoprecipitation (ChIP) and luciferase assays were performed to explore potential transcription factors (TFs) of selected glycoprotein. The regulation of repaglinide (RPG) on expression of lumican and downstream effectors was assessed by western blot and IHC, while its impact on malignant phenotypes of HCC was explored through in vitro and in vivo analyses, including a murine NASH-HCC model established using western diet and carbon tetrachloride (CCl4).

RESULTS

Lumican exhibited upregulation in both serum and tumor tissue, with elevated expression associated with an inferior prognosis in HCC patients. Knockdown of lumican resulted in significantly reduced growth of HCC in vitro and in vivo. Mechanically, lumican promoted HCC malignant phenotypes by inhibiting the p53/p21 signaling pathway. Forkhead Box O3 (FOXO3) was identified as the TF of lumican that transcriptionally enhanced its expression. Without silencing FOXO3, RPG blocked the binding of FOXO3 to the promoter region of lumican, thereby inhibiting the activation of lumican/p53/p21 axis. Mice treated with RPG developed fewer and smaller HCCs than those in the control group at 24 weeks after establishment.

CONCLUSION

Our results indicate that RPG prevented the development and progression of HCC via alteration of FOXO3/lumican/p53 axis.

N-linked glycosylation of PD-L1/PD-1: an emerging target for cancer diagnosis and treatment

During tumorigenesis and progression, the immune checkpoint programmed death-1 (PD-1) and its ligand programmed death ligand-1 (PD-L1) play critical roles in suppressing T cell-mediated anticancer immune responses, leading to T-cell exhaustion and subsequent tumor evasion. Therefore, anti-PD-L1/PD-1 therapy has been an attractive strategy for treating cancer over the past decade. However, the overall efficacy of this approach remains suboptimal, revealing an urgent need for novel insights. Interestingly, increasing evidence indicates that both PD-L1 on tumor cells and PD-1 on tumor-specific T cells undergo extensive N-linked glycosylation, which is essential for the stability and interaction of these proteins, and this modification promotes tumor evasion. In various preclinical models, targeting the N-linked glycosylation of PD-L1/PD-1 was shown to significantly increase the efficacy of PD-L1/PD-1 blockade therapy. Furthermore, deglycosylation of PD-L1 strengthens the signal intensity in PD-L1 immunohistochemistry (IHC) assays, improving the diagnostic and therapeutic relevance of this protein. In this review, we provide an overview of the regulatory mechanisms underlying the N-linked glycosylation of PD-L1/PD-1 as well as the crucial role of N-linked glycosylation in PD-L1/PD-1-mediated immune evasion. In addition, we highlight the promising implications of targeting the N-linked glycosylation of PD-L1/PD-1 in the clinical diagnosis and treatment of cancer. Our review identifies knowledge gaps and sheds new light on the cancer research field.

Quantitative Characterization of Protein N-Linked Core-Fucosylation by an Efficient Glycan Truncation Strategy

Dysregulation of protein core-fucosylation plays a pivotal role in the onset, progression, and immunosuppression of cancer. However, analyzing core-fucosylation, especially the accurate determination of the core-fucosylation (CF) site occupancy ratio, remains challenging. To address these problems, we developed a truncation strategy that efficiently converts intact glycopeptides with hundreds of different glycans into two truncated forms, i.e., a monosaccharide HexNAc and a disaccharide HexNAc+core-fucose. Further combination with data-independent analysis to form an integrated platform allowed the measurement of site-specific core-fucosylation abundances and the determination of the CF occupancy ratio with high reproducibility. Notably, three times CF sites were identified using this strategy compared to conventional methods based on intact glycopeptides. Application of this platform to characterize protein core-fucosylation in two breast cancer cell lines, i.e., MDA-MB-231 and MCF7, yields a total of 1615 unique glycosites and about 900 CF sites from one single LC-MS/MS analysis. Differential analysis unraveled the distinct glycosylation pattern for over 201 cell surface drug targets between breast cancer subtypes and provides insights into developing new therapeutic strategies to aid precision medicine. Given the robust performance of this platform, it would have broad application in discovering novel biomarkers based on the CF glycosylation pattern, investigating cancer mechanisms, as well as detecting new intervention targets.

Microbial lectins as a potential therapeutics for the prevention of certain human diseases

Lectins are protein or glycoprotein molecules with a specific ability to bind to carbohydrates. From viruses to mammals, they are found in various organisms and exhibit remarkable diverse structures and functions. They are significant contributors to defense mechanisms against microbial attacks in plants. They are also involved in functions such as controlling lymphocyte migration, regulating glycoprotein biosynthesis, cell-cell recognition, and embryonic development in animals. In addition, lectins serve as invaluable molecular tools in various biological and medical disciplines due to their reversible binding ability and enable the monitoring of cell membrane changes in physiological and pathological contexts. Microbial lectins, often referred to as adhesins, play an important role in microbial colonization, pathogenicity, and interactions among microorganisms. Viral lectins are located in the bilayered viral membrane, whereas bacterial lectins are found intracellularly and on the bacterial cell surface. Microfungal lectins are typically intracellular and have various functions in host-parasite interaction, and in fungal growth and morphogenesis. Although microbial lectin studies are less extensive than those of plants and animals, they provide insights into the infection mechanisms and potential interventions. Glycan specificity, essential functions in infectious diseases, and applications in the diagnosis and treatment of viral and bacterial infections are critical aspects of microbial lectin research. In this review, we will discuss the application and therapeutic potential of viral, bacterial and microfungal lectins.

A "One-Step" Strategy for the Global Characterization of Core-Fucosylated Glycoproteome

Core fucosylation, a special type of N-linked glycosylation, is important in tumor proliferation, invasion, metastatic potential, and therapy resistance. However, the core-fucosylated glycoproteome has not been extensively profiled due to the low abundance and poor ionization efficiency of glycosylated peptides. Here, a "one-step" strategy has been described for protein core-fucosylation characterization in biological samples. Core-fucosylated peptides can be selectively labeled with a glycosylated probe, which is linked with a temperature-sensitive poly(N-isopropylacrylamide) (PNIPAM) polymer, by mutant endoglycosidase (EndoF3-D165A). The labeled probe can be further removed by wild-type endoglycosidase (EndoF3) in a traceless manner for mass spectrometry (MS) analysis. The feasibility and effectiveness of the "one-step" strategy are evaluated in bovine serum albumin (BSA) spiked with standard core-fucosylated peptides, H1299, and Jurkat cell lines. The "one-step" strategy is then employed to characterize core-fucosylated sites in human lung adenocarcinoma, resulting in the identification of 2494 core-fucosylated sites distributed on 1176 glycoproteins. Further data analysis reveals that 196 core-fucosylated sites are significantly upregulated in tumors, which may serve as potential drug development targets or diagnostic biomarkers. Together, this "one-step" strategy has great potential for use in global and in-depth analysis of the core-fucosylated glycoproteome to promote its mechanism research.

Exploring ncRNA-mediated regulation of EGFR signalling in glioblastoma: From mechanisms to therapeutics

Glioblastoma (GBM) is the most prevalent and deadly primary brain tumor type, with a discouragingly low survival rate and few effective treatments. An important function of the EGFR signalling pathway in the development of GBM is to affect tumor proliferation, persistence, and treatment resistance. Advances in molecular biology in the last several years have shown how important ncRNAs are for controlling a wide range of biological activities, including cancer progression and development. NcRNAs have become important post-transcriptional regulators of gene expression, and they may affect the EGFR pathway by either directly targeting EGFR or by modifying important transcription factors and downstream signalling molecules. The EGFR pathway is aberrantly activated in response to the dysregulation of certain ncRNAs, which has been linked to GBM carcinogenesis, treatment resistance, and unfavourable patient outcomes. We review the literature on miRNAs, circRNAs and lncRNAs that are implicated in the regulation of EGFR signalling in GBM, discussing their mechanisms of action, interactions with the signalling pathway, and implications for GBM therapy. Furthermore, we explore the potential of ncRNA-based strategies to overcome resistance to EGFR-targeted therapies, including the use of ncRNA mimics or inhibitors to modulate the activity of key regulators within the pathway.

Tumor-suppressive miR-4732-3p is sorted into fucosylated exosome by hnRNPK to avoid the inhibition of lung cancer progression

BACKGROUND

Aberrant fucosylation observed in cancer cells contributes to an augmented release of fucosylated exosomes into the bloodstream, where miRNAs including miR-4732-3p hold promise as potential tumor biomarkers in our pilot study. However, the mechanisms underlying the sorting of miR-4732-3p into fucosylated exosomes during lung cancer progression remain poorly understood.

METHODS

A fucose-captured strategy based on lentil lectin-magnetic beads was utilized to isolate fucosylated exosomes and evaluate the efficiency for capturing tumor-derived exosomes using nanoparticle tracking analysis (NTA). Fluorescence in situ hybridization (FISH) and qRT-PCR were performed to determine the levels of miR-4732-3p in non-small cell lung cancer (NSCLC) tissue samples. A co-culture system was established to assess the release of miRNA via exosomes from NSCLC cells. RNA immunoprecipitation (RIP) and miRNA pull-down were applied to validate the interaction between miR-4732-3p and heterogeneous nuclear ribonucleoprotein K (hnRNPK) protein. Cell functional assays, cell derived xenograft, dual-luciferase reporter experiments, and western blot were applied to examine the effects of miR-4732-3p on MFSD12 and its downstream signaling pathways, and the impact of hnRNPK in NSCLC.

RESULTS

We enriched exosomes derived from NSCLC cells using the fucose-captured strategy and detected a significant upregulation of miR-4732-3p in fucosylated exosomes present in the serum, while its expression declined in NSCLC tissues. miR-4732-3p functioned as a tumor suppressor in NSCLC by targeting 3'UTR of MFSD12, thereby inhibiting AKT/p21 signaling pathway to induce cell cycle arrest in G2/M phase. NSCLC cells preferentially released miR-4732-3p via exosomes instead of retaining them intracellularly, which was facilitated by the interaction of miR-4732-3p with hnRNPK protein for selective sorting into fucosylated exosomes. Moreover, knockdown of hnRNPK suppressed NSCLC cell proliferation, with the elevated levels of miR-4732-3p in NSCLC tissues but the decreased expression in serum fucosylated exosomes.

CONCLUSIONS

NSCLC cells escape suppressive effects of miR-4732-3p through hnRNPK-mediated sorting of them into fucosylated exosomes, thus supporting cell malignant properties and promoting NSCLC progression. Our study provides a promising biomarker for NSCLC and opens a novel avenue for NSCLC therapy by targeting hnRNPK to prevent the "exosome escape" of tumor-suppressive miR-4732-3p from NSCLC cells.

High-Throughput Mass Spectrometry Analysis of N-Glycans and Protein Markers after FUT8 Knockdown in the Syngeneic SW480/SW620 Colorectal Cancer Cell Model

Disruption of the glycosylation machinery is a common feature in many types of cancer, and colorectal cancer (CRC) is no exception. Core fucosylation is mediated by the enzyme fucosyltransferase 8 (FucT-8), which catalyzes the addition of α1,6-l-fucose to the innermost GlcNAc residue of N-glycans. We and others have documented the involvement of FucT-8 and core-fucosylated proteins in CRC progression, in which we addressed core fucosylation in the syngeneic CRC model formed by SW480 and SW620 tumor cell lines from the perspective of alterations in their N-glycosylation profile and protein expression as an effect of the knockdown of the FUT8 gene that encodes FucT-8. Using label-free, semiquantitative mass spectrometry (MS) analysis, we found noticeable differences in N-glycosylation patterns in FUT8-knockdown cells, affecting core fucosylation and sialylation, the Hex/HexNAc ratio, and antennarity. Furthermore, stable isotopic labeling of amino acids in cell culture (SILAC)-based proteomic screening detected the alteration of species involved in protein folding, endoplasmic reticulum (ER) and Golgi post-translational stabilization, epithelial polarity, and cellular response to damage and therapy. This data is available via ProteomeXchange with identifier PXD050012. Overall, the results obtained merit further investigation to validate their feasibility as biomarkers of progression and malignization in CRC, as well as their potential usefulness in clinical practice.

Targeting branched N-glycans and fucosylation sensitizes ovarian tumors to immune checkpoint blockade

Aberrant glycosylation is a crucial strategy employed by cancer cells to evade cellular immunity. However, it's unclear whether homologous recombination (HR) status-dependent glycosylation can be therapeutically explored. Here, we show that the inhibition of branched N-glycans sensitizes HR-proficient, but not HR-deficient, epithelial ovarian cancers (EOCs) to immune checkpoint blockade (ICB). In contrast to fucosylation whose inhibition sensitizes EOCs to anti-PD-L1 immunotherapy regardless of HR-status, we observe an enrichment of branched N-glycans on HR-proficient compared to HR-deficient EOCs. Mechanistically, BRCA1/2 transcriptionally promotes the expression of MGAT5, the enzyme responsible for catalyzing branched N-glycans. The branched N-glycans on HR-proficient tumors augment their resistance to anti-PD-L1 by enhancing its binding with PD-1 on CD8+ T cells. In orthotopic, syngeneic EOC models in female mice, inhibiting branched N-glycans using 2-Deoxy-D-glucose sensitizes HR-proficient, but not HR-deficient EOCs, to anti-PD-L1. These findings indicate branched N-glycans as promising therapeutic targets whose inhibition sensitizes HR-proficient EOCs to ICB by overcoming immune evasion.

High-throughput analysis of glycan sorting into extracellular vesicles

Extracellular vesicles (EVs) are cell-released vesicles that mediate intercellular communication by transferring bioactive cargo. Protein and RNA sorting into EVs has been extensively assessed, while selective enrichment of glycans in EVs remains less explored. In this study, a mass spectrometry-based approach, glycan node analysis (GNA), was applied to broadly assess the sorting of glycan features into EVs. Two metastatic variants (lung and bone) generated in mouse modes from the MDA-MB-231 human breast cancer cell line were assessed, as these EVs are known to contain distinct organotropic biomolecules. EVs were isolated from conditioned cell culture medium by tangential flow filtration and authenticated by standard techniques. GNA analysis revealed selective enrichment of several glycan features in EVs compared to the originating cells, particularly those associated with binding to the extracellular matrix, which was also observed in EVs from the parental MDA-MB-231 cell line (human pleural metastases). The bone-tropic variant displayed enrichment of distinct EV glycan features compared to the lung-tropic one. Additionally, the metastatic variants generated in mouse models displayed reduced EV glycan sorting compared to the parental metastatic cell line. This study represents the first comprehensive assessment of differences in glycan features between EVs and originating cells and provides evidence that the diversity of EV glycan sorting is reduced upon generation of variant cell lines in mouse models. Future research is likely to uncover novel mechanisms of EV glycan sorting, shed light on glycan features for EV authentication or biomarker purposes, and assess functional roles of the EV glycocode in (patho)physiology.

Identification of molecular characteristics of FUT8 and alteration of core fucosylation in kidney renal clear cell cancer

BACKGROUND

Kidney renal clear cell cancer (KIRC) is a type of urological cancer that occurs worldwide. Core fucosylation (CF), as the most common post-translational modification, is involved in the tumorigenesis.

METHODS

The alterations of CF-related genes were summarized in pan-cancer. The "ConsensusClusterPlus" package was utilized to identify two CF-related KIRC subtypes. The "ssgsea" function was chosen to estimate the CF score, signaling pathways and cell deaths. Multiple algorithms were applied to assess immune responses. The "oncoPredict" was utilized to estimate the drug sensitivity. The IHC and subgroup analysis was performed to reveal the molecular features of FUT8. Single-cell RNA sequencing (scRNA-seq) data were scrutinized to evaluate the CF state.

RESULTS

In pan-cancer, there was a noticeable alteration in the expression of CF-related genes. In KIRC, two CF-related subtypes (i.e., C1, C2) were obtained. In comparison to C2, C1 exhibited a higher CF score and correlated with poorer overall survival. Additionally, the TME of C2 demonstrated increased activity in neutrophils, macrophages, myeloid dendritic cells, and B cells, alongside a higher presence of silent mast cells, NK cells, and endothelial cells. Compared to normal samples, higher expression of FUT8 is observed in KIRC. The mutation of SETD2 was more frequent in low-FUT8 samples while the mutation of DNAH9 was more frequent in high-FUT8 samples. scRNA-seq analyses revealed that the CF score was predominantly higher in endothelial cells and fibroblast cells.

CONCLUSIONS

Two CF-related subtypes with distinct prognosis and TME were identified in KIRC. FUT8 exhibited elevated expression in KIRC samples.

The Multifaceted Role of FUT8 in Tumorigenesis: From Pathways to Potential Clinical Applications

FUT8, the sole glycosyltransferase responsible for N-glycan core fucosylation, plays a crucial role in tumorigenesis and development. Aberrant FUT8 expression disrupts the function of critical cellular components and triggers the abnormality of tumor signaling pathways, leading to malignant transformations such as proliferation, invasion, metastasis, and immunosuppression. The association between FUT8 and unfavorable outcomes in various tumors underscores its potential as a valuable diagnostic marker. Given the remarkable variation in biological functions and regulatory mechanisms of FUT8 across different tumor types, gaining a comprehensive understanding of its complexity is imperative. Here, we review how FUT8 plays roles in tumorigenesis and development, and how this outcome could be utilized to develop potential clinical therapies for tumors.

Serum-based Comprehensive N-Glycans Profiling Analysis in Different Gastric Disease Stages by Porous Graphitic Carbon Liquid Chromatography-Mass Spectrometry Associated With Potential Marker Discovery

BACKGROUND/AIM

N-glycans are potential serum biomarkers due to their aberrant structure and abundance alteration during disease progression. Few studies have been associated with relative quantitative N-glycans profiling during different gastric disease stages. In this study, we conducted an investigation on the profiling of N-glycans in patients with gastric disease, as well as in healthy controls.

MATERIALS AND METHODS

In this study, the porous graphitization carbon chromatography-high resolution Fourier transform mass spectrometry (PGC-FTMS) method was applied to assess comprehensive N-glycans profiling in patients at different stages of gastric disease, including gastritis, atrophic gastritis, gastric ulcer, gastric polyps, and gastric cancer.

RESULTS

A total of 45 N-glycans (relative abundance >0.1%) were detected, and 9 N-glycans were found to be potential biomarkers for gastric disease detection. Along with the progression of gastric disease, the abundance of sialylated N-glycans increased, while that of core-fucosylated N-glycans decreased. Multivariate statistical analysis demonstrated that N-glycans profiling between gastritis and healthy controls had significant differences. The characteristic N-glycans distinguished gastric cancer from healthy controls, which had strong clinical diagnostic value.

CONCLUSION

The relative quantitative profile of N-glycans in different gastric disease stages was revealed and serum N-glycans are proposed for distinguishing gastric disease stages in clinical application.

Aberrant fucosylation sustains the NOTCH and EGFR/NF-κB pathways and has a prognostic value in human intrahepatic cholangiocarcinoma

BACKGROUND AND AIMS

Intrahepatic cholangiocarcinoma (iCCA) is a lethal malignancy, with increasing incidence worldwide and limited therapeutic options. Aberrant protein glycosylation is a hallmark of cancer. Here, we thoroughly investigated the possible involvement of fucosylation in cholangiocarcinogenesis.

APPROACH AND RESULTS

We discovered that the levels of global fucosylation and members of the fucosylation pathway are ubiquitously upregulated in human iCCA tissues compared to nontumorous surrounding livers and normal biliary cells. In addition, total fucosylation levels correlate with poor patients' prognosis. Furthermore, fucosylation inhibition following 6-alkynylfucose (6AF) administration triggered a dose-dependent decrease in the proliferation and migration of iCCA cell lines. Notably, adding fucose to the cell medium annulled these effects. At the molecular level, 6AF administration or small interfering RNA-mediated silencing of GDP-L-fucose synthetase (FX) and the GDP-fucose transmembrane transporter (SLC35C1), both pivotal players of cellular fucosylation, decreased NOTCH activity, NOTCH1/Jagged1 interaction, NOTCH receptors, and related target genes in iCCA cell lines. In the same cells, EGFR, nuclear factor kappa-light-chain-enhancer of activated B cells p65, and Bcl-xL protein levels diminished, whereas IκBα (a critical cellular NF-κB inhibitor) increased after FX/SLC35C1 knockdown or 6AF administration. In the chick chorioallantoic membrane assay, 6AF treatment profoundly suppresses the growth of iCCA cells.

CONCLUSIONS

Elevated global fucosylation characterizes human iCCA, contributing to cell growth and migration through the upregulation of the NOTCH and EGFR/NF-κB pathways. Thus, aberrant fucosylation is a novel pathogenetic player and a potential therapeutic target for human iCCA.

Ablation of the GDP-fucose transporter suppresses lung cancer cell proliferation and migration by reducing expression of PD-L1

Fucosylation, an important post-translational modification, is closely related to the development of tumors. In the microenvironment of lung cancer, expression of PD-L1 and fucosylation is abnormally upregulated. However, the correlation between PD-L1 expression and its fucosylation in lung adenocarcinoma (LUAD) remains unclear. The GDP-fucose transporter (GFT) is a key molecule in cellular fucosylation. To explore the correlation between fucosylation and PD-L1 expression, we knocked out the GFT-encoding gene SLC35C1 in mouse Lewis lung adenocarcinoma cells and in human H1299 lung adenocarcinoma cells. Loss of SLC35C1 impaired the phosphorylation of EGFR and its downstream target ERK. Moreover, loss of SLC35C1 up-regulated the expression of β-TrCP, a PD-L1 E3 ligase, thereby promoting the ubiquitination of PD-L1 and its subsequent degradation. The down-regulated expression of PD-L1 leads to a decline in lung cancer cell proliferation and migration. These results suggest that fucosylation partially influences LUAD tumorigenesis by regulating PD-L1 expression.

Ti3C2 and Ti2C MXene materials for high-performance isolation of extracellular vesicles via coprecipitation

Two-dimensional (2D) materials such as MXenes, are usually well utilized in the field of catalysts and battery due to their good hydrophilicity and diversified surface terminals. However, their potential applications in the treatment of biological samples have not been widely concerned. Extracellular vesicles (EVs) contain unique molecular signatures and could be used as biomarkers for the detection of severe diseases such as cancer, as well as monitoring the therapeutic response. In this work, two kinds of MXene materials (Ti₃C₂ and Ti₂C) were successfully synthesized and employed in the isolation of EVs from the biological samples by taking advantage of the affinity interaction between the titanium (Ti) in MXenes and the phospholipid membrane of EVs. Compared with Ti₂C MXene materials, TiO₂ beads and the other EVs isolation methods, Ti₃C₂ MXene materials exhibited excellent isolation performance via the coprecipitation with EVs due to the abundant unsaturated coordination of Ti²⁺/Ti³⁺, and the dosage of materials was the lowest. Meanwhile, the whole isolation process could be done within 30 min and integrated well with the following analysis of proteins and ribonucleic acids (RNAs), which was also convenient and economic. Furthermore, the Ti₃C₂ MXene materials were used to isolate the EVs from the blood plasma of colorectal cancer (CRC) patients and healthy donors. Proteomics analysis of EVs showed that 67 proteins were up-regulated, in which most of them were closely related to CRC progression. These findings indicate that the MXene material-based EVs isolation method via coprecipitation provides an efficient tool for early diagnosis of diseases.

Core Fucosylation Mediated by the FucT-8 Enzyme Affects TRAIL-Induced Apoptosis and Sensitivity to Chemotherapy in Human SW480 and SW620 Colorectal Cancer Cells

Epithelial cells can undergo apoptosis by manipulating the balance between pro-survival and apoptotic signals. In this work, we show that TRAIL-induced apoptosis can be differentially regulated by the expression of α(1,6)fucosyltransferase (FucT-8), the only enzyme in mammals that transfers the α(1,6)fucose residue to the pentasaccharide core of complex N-glycans. Specifically, in the cellular model of colorectal cancer (CRC) progression formed using the human syngeneic lines SW480 and SW620, knockdown of the FucT-8-encoding FUT8 gene significantly enhanced TRAIL-induced apoptosis in SW480 cells. However, FUT8 repression did not affect SW620 cells, which suggests that core fucosylation differentiates TRAIL-sensitive premetastatic SW480 cells from TRAIL-resistant metastatic SW620 cells. In this regard, we provide evidence that phosphorylation of ERK1/2 kinases can dynamically regulate TRAIL-dependent apoptosis and that core fucosylation can control the ERK/MAPK pro-survival pathway in which SW480 and SW620 cells participate. Moreover, the depletion of core fucosylation sensitises primary tumour SW480 cells to the combination of TRAIL and low doses of 5-FU, oxaliplatin, irinotecan, or mitomycin C. In contrast, a combination of TRAIL and oxaliplatin, irinotecan, or bevacizumab reinforces resistance of FUT8-knockdown metastatic SW620 cells to apoptosis. Consequently, FucT-8 could be a plausible target for increasing apoptosis and drug response in early CRC.

Systematic pan-cancer analysis identifies SLC35C1 as an immunological and prognostic biomarker

GDP-amylose transporter protein 1 (SLC35C1) plays an important role in many types of cancer. Therefore, it is clinically important to further investigate the expression profile of SLC35C1 in human tumors to provide new molecular clues for the pathogenesis of glioma. In this study, we performed a comprehensive pan-cancer analysis of SLC35C1 using a series of bioinformatics approaches and validated its differential tissue expression and biological function. The results showed that SLC35C1 was aberrantly expressed in different types of tumors and significantly correlated with overall survival (OS) and progression-free interval (PFI). More importantly, the expression level of SLC35C1 was closely correlated with Tumor Microenvironment (TME), immune infiltration and immune-related genes. In addition, we found that SLC35C1 expression was also closely related to Tumor Mutation Burden (TMB), Microsatellite Instability (MSI) and antitumor drug sensitivity in various cancer types. Functional bioinformatics analysis indicated that SLC35C1 may be involved in multiple signaling pathways and biological processes in glioma. Based on SLC35C1 expression, a risk factor model was found to predict OS of glioma. In addition, in vitro experiments showed that SLC35C1 knockdown significantly inhibited the proliferation, migration and invasive ability of glioma cells, while SLC35C1 overexpression promoted proliferation, migration, invasion and colony formation of glioma cells. Finally, quantitative real-time PCR confirmed that SLC35C1 was highly expressed in gliomas.

Beyond antibody fucosylation: α-(1,6)-fucosyltransferase (Fut8) as a potential new therapeutic target for cancer immunotherapy

Aberrant post-translational glycosylation is a well-established hallmark of cancer. Altered core fucosylation mediated by α-(1,6)-fucosyltransferase (Fut8) is one of the key changes in tumor glycan patterns that contributes to neoplastic transformation, tumor metastasis, and immune evasion. Increased Fut8 expression and activity are associated with many types of human cancers, including lung, breast, melanoma, liver, colorectal, ovarian, prostate, thyroid, and pancreatic cancer. In animal models, inhibition of Fut8 activity by gene knockout, RNA interference, and small analogue inhibitors led to reduced tumor growth/metastasis, downregulation of immune checkpoint molecules PD-1, PD-L1/2, and B7-H3, and reversal of the suppressive state of tumor microenvironment. Although the biologics field has long benefited tremendously from using FUT8 -/- Chinese hamster ovary cells to manufacture IgGs with greatly enhanced effector function of antibody-dependent cellular cytotoxicity for therapy, it is only in recent years that the roles of Fut8 itself in cancer biology have been studied. Here, we summarize the pro-oncogenic mechanisms involved in cancer development that are regulated by Fut8-mediated core fucosylation, and call for more research in this area where modifying the activity of this sole enzyme responsible for core fucosylation could potentially bring rewarding surprises in fighting cancer, infections, and other immune-related diseases.

α-1,6-fucosyltransferase plays a critical role during embryogenesis of the hemimetabolous insect Nilaparvata lugens

Protein glycosylation is one of the most important post-translational modifications, modulating the properties of proteins. In insects, α-1,6-fucosyltransferase (FucT6) is an important enzyme in the glycosylation pathway, modifying the core structure of N-glycans on glycoproteins with the addition of a fucose residue. In our previous study, RNAi-mediated silencing of FucT6 in the third-instar nymphs of Nilaparvata lugens caused a failure of the ecdysis process during nymphal development, leading to high mortality. These results suggested the requirement of FucT6 during nymphal development in N. lugens. In this study, RNAi-mediated gene silencing of FucT6 in adults did not cause lethality. However, parental RNAi of FucT6 led to full failure in the hatching of eggs, and this effect was maternally mediated. Interestingly, gene expression levels of FucT6 in the eggs peaked at the katatrepsis event, where the embryo rotates 180° resulting in the head pointing towards the anterior side of the egg. Proteome analysis showed significant differences in the abundance of proteins between different embryonal developmental stages, suggesting the crucial role of FucT6 mediated core N-fucosylation in embryonal development. Therefore, correct α-1,6-fucosylation of glycoproteins is important for N. lugens during embryonic development and this study provides new insights into the role of N-glycosylation in embryogenesis in insects.

Identification of gene profiles related to the development of oral cancer using a deep learning technique

BACKGROUND

Oral cancer (OC) is a debilitating disease that can affect the quality of life of these patients adversely. Oral premalignant lesion patients have a high risk of developing OC. Therefore, identifying robust survival subgroups among them may significantly improve patient therapy and care. This study aimed to identify prognostic biomarkers that predict the time-to-development of OC and survival stratification for patients using state-of-the-art machine learning and deep learning.

METHODS

Gene expression profiles (29,096 probes) related to 86 patients from the GSE26549 dataset from the GEO repository were used. An autoencoder deep learning neural network model was used to extract features. We also used a univariate Cox regression model to select significant features obtained from the deep learning method (P < 0.05). High-risk and low-risk groups were then identified using a hierarchical clustering technique based on 100 encoded features (the number of units of the encoding layer, i.e., bottleneck of the network) from autoencoder and selected by Cox proportional hazards model and a supervised random forest (RF) classifier was used to identify gene profiles related to subtypes of OC from the original 29,096 probes.

RESULTS

Among 100 encoded features extracted by autoencoder, seventy features were significantly related to time-to-OC-development, based on the univariate Cox model, which was used as the inputs for the clustering of patients. Two survival risk groups were identified (P value of log-rank test = 0.003) and were used as the labels for supervised classification. The overall accuracy of the RF classifier was 0.916 over the test set, yielded 21 top genes (FUT8-DDR2-ATM-CD247-ETS1-ZEB2-COL5A2-GMAP7-CDH1-COL11A2-COL3A1-AHR-COL2A1-CHORDC1-PTP4A3-COL1A2-CCR2-PDGFRB-COL1A1-FERMT2-PIK3CB) associated with time to developing OC, selected among the original 29,096 probes.

CONCLUSIONS

Using deep learning, our study identified prominent transcriptional biomarkers in determining high-risk patients for developing oral cancer, which may be prognostic as significant targets for OC therapy. The identified genes may serve as potential targets for oral cancer chemoprevention. Additional validation of these biomarkers in experimental prospective and retrospective studies will launch them in OC clinics.

Hypofucosylation of Unc5b regulated by Fut8 enhances macrophage emigration and prevents atherosclerosis

BACKGROUND

Atherosclerosis (AS) is the leading underlying cause of the majority of clinical cardiovascular events. Retention of foamy macrophages in plaques is the main factor initiating and promoting the atherosclerotic process. Our previous work showed that ox-LDL induced macrophage retention in plaques and that the guidance receptor Uncoordinated-5 homolog B (Unc5b) was involved in this process. However, little is known about the role of Unc5b in regulating macrophage accumulation within plaques.

RESULTS

In the present study, we found that Unc5b controls macrophage migration and thus promotes plaque progression in ApoE^-/- mice. The immunofluorescence colocalization assay results first suggested that fucosyltransferase 8 (Fut8) might participate in the exacerbation of atherosclerosis. Animals with Unc5b overexpression showed elevated levels of Fut8 and numbers of macrophages and an increased lesion size and intimal thickness. However, these effects were reversed in ApoE^-/- mice with Unc5b knockdown. Furthermore, Raw264.7 macrophages with siRNA-mediated silencing of Unc5b or overexpression of Unc5b were used to confirm the regulatory mechanisms of Unc5b and Fut8 in vitro. In response to ox-LDL exposure, Unc5b and Fut8 were both upregulated, and macrophages showed reduced pseudopod formation and migratory capacities. However, these capacities were restored by blocking Unc5b or Fut8. Furthermore, the IP assay indicated that Fut8 regulated the level of α-1,6 fucosylation of Unc5b, which mainly occurs in the endoplasmic reticulum (ER), and genetic deletion of the main fucosylation sites or Fut8 resulted in hypofucosylation of Unc5b. Moreover, the macrophage migration mediated by Unc5b depended on inactivation of the p-CDC42/p-PAK pathway. Conversely, macrophages with Unc5b overexpression displayed activation of the p-CDC42/p-PAK pathway and decreased migration both in vivo and in vitro.

CONCLUSION

These results demonstrated that hypofucosylation of Unc5b regulated by Fut8 is positively associated with the delay of the atherosclerotic process by promoting the migration of foamy macrophages. These findings identify a promising therapeutic target for atherosclerosis.

Aberrant L-Fucose Accumulation and Increased Core Fucosylation Are Metabolic Liabilities in Mesenchymal Glioblastoma

Glioblastoma (GBM) is a common and deadly form of brain tumor in adults. Dysregulated metabolism in GBM offers an opportunity to deploy metabolic interventions as precise therapeutic strategies. To identify the molecular drivers and the modalities by which different molecular subgroups of GBM exploit metabolic rewiring to sustain tumor progression, we interrogated the transcriptome, the metabolome, and the glycoproteome of human subgroup-specific GBM sphere-forming cells (GSC). L-fucose abundance and core fucosylation activation were elevated in mesenchymal (MES) compared with proneural GSCs; this pattern was retained in subgroup-specific xenografts and in subgroup-affiliated human patient samples. Genetic and pharmacological inhibition of core fucosylation significantly reduced tumor growth in MES GBM preclinical models. Liquid chromatography-mass spectrometry (LC-MS)-based glycoproteomic screening indicated that most MES-restricted core-fucosylated proteins are involved in therapeutically relevant GBM pathological processes, such as extracellular matrix interaction, cell adhesion, and integrin-mediated signaling. Selective L-fucose accumulation in MES GBMs was observed using preclinical minimally invasive PET, implicating this metabolite as a potential subgroup-restricted biomarker.Overall, these findings indicate that L-fucose pathway activation in MES GBM is a subgroup-specific dependency that could provide diagnostic markers and actionable therapeutic targets.

SIGNIFICANCE

Metabolic characterization of subgroup-specific glioblastoma (GBM) sphere-forming cells identifies the L-fucose pathway as a vulnerability restricted to mesenchymal GBM, disclosing a potential precision medicine strategy for targeting cancer metabolism.

Defining the altered glycoproteomic space of the early secretory pathway by class I mannosidase pharmacological inhibition

N-glycosylation is a key process for various biological functions like protein folding, maturation and sorting for the conventional secretory compartment, cell-cell communication and immune response. This is usually accomplished by a complex system of mannosidases in which those from class I have an outstanding role, commonly involved in the early protein sorting associated to the Endoplasmic Reticulum (ER) in the N-glycan dependent quality control (ERQC) and ER-associated degradation (ERAD). Although these are vital processes in maintaining cellular homeostasis, large-scale analysis studies for this pool of molecules, further denoted as proteins from the early secretory pathway (ESP), were limited addressed. Here, using a custom workflow employing a combination of glycomics and deglycoproteomics analyses, using lectin affinity and selective Endoglycosidase H (Endo H) digestion, we scrutinize the steady-state oligomannosidic glycoprotein load and delineate ESP fraction in melanoma cells. All of these were assessed by applying our workflow for glycosite relative quantification of both the peptide chain and carbohydrate structure in cells with inhibited activity of class I mannosidases after kifunensine treatment. We found that most of the ESP are transient clients involved in cell communication via extracellular matrix, particularly integrin-mediated communication which adopt Man9 N-glycans in kifunensine-treated cells. Moreover, our results reveal that core-fucosylation is decreased subsequent inhibition of class I mannosidases and this could be explained by a general lower protein level of FUT8, the enzyme responsible for fucosylation. By comparing our data with results obtained following downregulation of a key mannosidase in misfolded protein degradation, we mapped both novel and previously suggested endogenous substrate candidates like PCDH2, HLA-B, LAMB2 or members of the integrin family of proteins such as ITGA1 and ITGA4, thus validating the findings obtained using our workflow regarding accumulation and characterization of ESP transitory members following mannosidase class I inhibition. This workflow and the associated dataset not only allowed us to investigate the oligomannosidic glycoprotein fraction but also to delineate differences mediated at glycosite-level upon kifunensine treatment and outline the potential associated cellular responses.

FUT6 inhibits the proliferation, migration, invasion, and EGF-induced EMT of head and neck squamous cell carcinoma (HNSCC) by regulating EGFR/ERK/STAT signaling pathway

Glycosylation change is one of the landmark events of tumor occurrence and development, and tumor cells may be inhibited by regulating the aberrant expression of glycosyltransferases. Currently, fucosyltransferase VI (FUT6), which is involved in the synthesis of α-1, 3 fucosyl bond, has been detected to be closely associated with multiple tumors, but its function and mechanism in head and neck squamous cell carcinoma (HNSCC) still need further research. In this study, FUT6 knockdown and overexpression strategies were used to investigate the effects of FUT6 on cell proliferation, migration, and invasion, as well as the growth and metastasis of HNSCC in a xenografts mouse model. The protein expression levels of epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK), Signal Transducer and Activator of Transcription (STAT), protein kinase B (AKT), c-Myc, and epithelial-mesenchymal transition (EMT) markers were determined by western blot analysis. Our research found that the mRNA expression of FUT6 was lower in HNSCC tissues than in normal mucosal epithelial tissues. In Cal-27 and FaDu cells, FUT6 overexpression inhibited cell proliferation, migration and invasion, causing upregulation of ZO-1 and E-cadherin, downregulation of N-cadherin and Vimentin, and finally decreased the phosphorylation levels of EGFR, ERK, STAT, and c-Myc. In HSC-3 cells, knockdown of FUT6 promoted cell proliferation, migration and invasion, downregulating ZO-1 and E-cadherin, upregulating N-cadherin and Vimentin, and increased the phosphorylation levels of EGFR, ERK, STAT, and c-Myc. In the HNSCC xenografts mouse, FUT6 overexpression inhibited tumor growth and metastasis. In summary, FUT6 controls the proliferation, migration, invasion, and EGF-induced EMT of HNSCC by regulating EGFR/ERK/STAT signaling pathway, indicating its potential future therapeutic application for HNSCC.

B7 family protein glycosylation: Promising novel targets in tumor treatment

Cancer immunotherapy, including the inhibition of immune checkpoints, improves the tumor immune microenvironment and is an effective tool for cancer therapy. More effective and alternative inhibitory targets are critical for successful immune checkpoint blockade therapy. The interaction of the immunomodulatory ligand B7 family with corresponding receptors induces or inhibits T cell responses by sending co-stimulatory and co-inhibitory signals respectively. Blocking the glycosylation of the B7 family members PD-L1, PD-L2, B7-H3, and B7-H4 inhibited the self-stability and receptor binding of these immune checkpoint proteins, leading to immunosuppression and rapid tumor progression. Therefore, regulation of glycosylation may be the "golden key" to relieve tumor immunosuppression. The exploration of a more precise glycosylation regulation mechanism and glycan structure of B7 family proteins is conducive to the discovery and clinical application of antibodies and small molecule inhibitors.

Inhibition of α(1,6)fucosyltransferase: Effects on Cell Proliferation, Migration, and Adhesion in an SW480/SW620 Syngeneic Colorectal Cancer Model

The present study explored the impact of inhibiting α(1,6)fucosylation (core fucosylation) on the functional phenotype of a cellular model of colorectal cancer (CRC) malignization formed by the syngeneic SW480 and SW620 CRC lines. Expression of the FUT8 gene encoding α(1,6)fucosyltransferase was inhibited in tumor line SW480 by a combination of shRNA-based antisense knockdown and Lens culinaris agglutinin (LCA) selection. LCA-resistant clones were subsequently assayed in vitro for proliferation, migration, and adhesion. The α(1,6)FT-inhibited SW480 cells showed enhanced proliferation in adherent conditions, unlike their α(1,6)FT-depleted SW620 counterparts, which displayed reduced proliferation. Under non-adherent conditions, α(1,6)FT-inhibited SW480 cells also showed greater growth capacity than their respective non-targeted control (NTC) cells. However, cell migration decreased in SW480 after FUT8 knockdown, while adhesion to EA.hy926 cells was significantly enhanced. The reported results indicate that the FUT8 knockdown strategy with subsequent selection for LCA-resistant clones was effective in greatly reducing α(1,6)FT expression in SW480 and SW620 CRC lines. In addition, α(1,6)FT impairment affected the proliferation, migration, and adhesion of α(1,6)FT-deficient clones SW480 and SW620 in a tumor stage-dependent manner, suggesting that core fucosylation has a dynamic role in the evolution of CRC.

CD44 Glycosylation as a Therapeutic Target in Oncology

The interaction of non-kinase transmembrane glycoprotein CD44 with ligands including hyaluronic acid (HA) is closely related to the occurrence and development of tumors. Changes in CD44 glycosylation can regulate its binding to HA, Siglec-15, fibronectin, TM4SF5, PRG4, FGF2, collagen and podoplanin and activate or inhibit c-Src/STAT3/Twist1/Bmi1, PI3K/AKT/mTOR, ERK/NF-κB/NANOG and other signaling pathways, thereby having a profound impact on the tumor microenvironment and tumor cell fate. However, the glycosylation of CD44 is complex and largely unknown, and the current understanding of how CD44 glycosylation affects tumors is limited. These issues must be addressed before targeted CD44 glycosylation can be applied to treat human cancers.

Identification of Novel Prognostic Markers Associated With Laryngeal Squamous Cell Carcinoma Using Comprehensive Analysis

Background

Laryngeal squamous cell carcinoma (LSCC) is a leading malignant cancer of the head and neck. Patients with LSCC, in which the cancer has infiltrated and metastasized, have a poor prognosis. Therefore, there is an urgent need to identify more potential targets for drugs and biomarkers for early diagnosis.

Methods

RNA sequence data from LSCC and patients’ clinical traits were obtained from the Gene Expression Omnibus (GEO) (GSE142083) and The Cancer Genome Atlas (TCGA) database. Differentially expressed gene (DEG) analysis and weighted gene co-expression network analysis (WGCNA) were performed to identify hub genes. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, prognostic value analysis, receiver operating characteristic (ROC) curve analysis, gene mutation analysis, tumor-infiltrating immune cell abundance profile estimation, gene set variation analysis (GSVA), and gene set enrichment analysis (GSEA) were performed. Single-gene RNA sequencing data were obtained from the GSE150321 dataset. Cell proliferation and viability were confirmed by the CCK-8 assay and real-time PCR.

Results

A total of 701 DEGs, including 329 upregulated and 372 downregulated genes, were screened in the GSE142083 dataset. Using WGCNA, three modules were identified to be closely related to LSCC. After intersecting the DEGs and performing univariate and multivariate Cox analyses, a novel prognostic model based on three genes (SLC35C1, HOXB7, and TEDC2) for LSCC was established. Interfering TEDC2 expression inhibited tumor cell proliferation and migration.

Conclusions

Our results show that SLC35C1, HOXB7, and TEDC2 have the potential to become new therapeutic targets and prognostic biomarkers for LSCC.