Cellular glycosylation senses metabolic changes and modulates cell plasticity during epithelial to mesenchymal transition

Overexpression of Fatty Acid Synthase Upregulates Glutamine-Fructose-6-Phosphate Transaminase 1 and O-Linked N-Acetylglucosamine Transferase to Increase O-GlcNAc Protein Glycosylation and Promote Colorectal Cancer Growth

Fatty acid synthesis has been extensively investigated as a therapeutic target in cancers, including colorectal cancer (CRC). Fatty acid synthase (FASN), a key enzyme of de novo lipid synthesis, is significantly upregulated in CRC, and therapeutic approaches of targeting this enzyme are currently being tested in multiple clinical trials. However, the mechanisms behind the pro-oncogenic action of FASN are still not completely understood. Here, for the first time, we show that overexpression of FASN increases the expression of glutamine-fructose-6-phosphate transaminase 1 (GFPT1) and O-linked N-acetylglucosamine transferase (OGT), enzymes involved in hexosamine metabolism, and the level of O-GlcNAcylation in vitro and in vivo. Consistently, expression of FASN significantly correlates with expression of GFPT1 and OGT in human CRC tissues. shRNA-mediated downregulation of GFPT1 and OGT inhibits cellular proliferation and the level of protein O-GlcNAcylation in vitro, and knockdown of GFPT1 leads to a significant decrease in tumor growth and metastasis in vivo. Pharmacological inhibition of GFPT1 and OGT leads to significant inhibition of cellular proliferation and colony formation in CRC cells. In summary, our results show that overexpression of FASN increases the expression of GFPT1 and OGT as well as the level of protein O-GlcNAcylation to promote progression of CRC; targeting the hexosamine biosynthesis pathway could be a therapeutic approach for this disease.

Targeting O-GlcNAcylation in cancer therapeutic resistance: The sugar Saga continues

O-linked-N-acetylglucosaminylation (O-GlcNAcylation), a dynamic post-translational modification (PTM), holds profound implications in controlling various cellular processes such as cell signaling, metabolism, and epigenetic regulation that influence cancer progression and therapeutic resistance. From the therapeutic perspective, O-GlcNAc modulates drug efflux, targeting and metabolism. By integrating signals from glucose, lipid, amino acid, and nucleotide metabolic pathways, O-GlcNAc acts as a nutrient sensor and transmits signals to exerts its function on genome stability, epithelial-mesenchymal transition (EMT), cell stemness, cell apoptosis, autophagy, cell cycle. O-GlcNAc also attends to tumor microenvironment (TME) and the immune response. At present, several strategies aiming at targeting O-GlcNAcylation are under mostly preclinical evaluation, where the newly developed O-GlcNAcylation inhibitors markedly enhance therapeutic efficacy. Here we systematically outline the mechanisms through which O-GlcNAcylation influences therapy resistance and deliberate on the prospects and challenges associated with targeting O-GlcNAcylation in future cancer treatments.

Tolerable glycometabolic stress boosts cancer cell resilience through altered N-glycosylation and Notch signaling activation

Chronic metabolic stress paradoxically elicits pro-tumorigenic signals that facilitate cancer stem cell (CSC) development. Therefore, elucidating the metabolic sensing and signaling mechanisms governing cancer cell stemness can provide insights into ameliorating cancer relapse and therapeutic resistance. Here, we provide convincing evidence that chronic metabolic stress triggered by hyaluronan production augments CSC-like traits and chemoresistance by partially impairing nucleotide sugar metabolism, dolichol lipid-linked oligosaccharide (LLO) biosynthesis and N-glycan assembly. Notably, preconditioning with either low-dose tunicamycin or 2-deoxy-D-glucose, which partially interferes with LLO biosynthesis, reproduced the promoting effects of hyaluronan production on CSCs. Multi-omics revealed characteristic changes in N-glycan profiles and Notch signaling activation in cancer cells exposed to mild glycometabolic stress. Restoration of N-glycan assembly with glucosamine and mannose supplementation and Notch signaling blockade attenuated CSC-like properties and further enhanced the therapeutic efficacy of cisplatin. Therefore, our findings uncover a novel mechanism by which tolerable glycometabolic stress boosts cancer cell resilience through altered N-glycosylation and Notch signaling activation.

TGF-β uncouples glycolysis and inflammation in macrophages and controls survival during sepsis

Changes in metabolism of macrophages are required to sustain macrophage activation in response to different stimuli. We showed that the cytokine TGF-β (transforming growth factor-β) regulates glycolysis in macrophages independently of inflammatory cytokine production and affects survival in mouse models of sepsis. During macrophage activation, TGF-β increased the expression and activity of the glycolytic enzyme PFKL (phosphofructokinase-1 liver type) and promoted glycolysis but suppressed the production of proinflammatory cytokines. The increase in glycolysis was mediated by an mTOR-c-MYC-dependent pathway, whereas the inhibition of cytokine production was due to activation of the transcriptional coactivator SMAD3 and suppression of the activity of the proinflammatory transcription factors AP-1, NF-κB, and STAT1. In mice with LPS-induced endotoxemia and experimentally induced sepsis, the TGF-β-induced enhancement in macrophage glycolysis led to decreased survival, which was associated with increased blood coagulation. Analysis of septic patient cohorts revealed that the expression of PFKL, TGFBRI (which encodes a TGF-β receptor), and F13A1 (which encodes a coagulation factor) in myeloid cells positively correlated with COVID-19 disease. Thus, these results suggest that TGF-β is a critical regulator of macrophage metabolism and could be a therapeutic target in patients with sepsis.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

Glycoinformatics in the Artificial Intelligence Era

Artificial intelligence (AI) methods have been and are now being increasingly integrated in prediction software implemented in bioinformatics and its glycoscience branch known as glycoinformatics. AI techniques have evolved in the past decades, and their applications in glycoscience are not yet widespread. This limited use is partly explained by the peculiarities of glyco-data that are notoriously hard to produce and analyze. Nonetheless, as time goes, the accumulation of glycomics, glycoproteomics, and glycan-binding data has reached a point where even the most recent deep learning methods can provide predictors with good performance. We discuss the historical development of the application of various AI methods in the broader field of glycoinformatics. A particular focus is placed on shining a light on challenges in glyco-data handling, contextualized by lessons learnt from related disciplines. Ending on the discussion of state-of-the-art deep learning approaches in glycoinformatics, we also envision the future of glycoinformatics, including development that need to occur in order to truly unleash the capabilities of glycoscience in the systems biology era.

Glycosylation modification patterns reveal distinct tumor metabolism and immune microenvironment landscape in lower-grade gliomas

Glycosylation alterations, a key driver throughout tumorigenesis and tumor progression, could regulate the microenvironment and immune response as well as lead to harmful metabolism and cell signaling. In this study, we first comprehensively evaluated the glycosylation modification patterns of LGGs based on glycosyltransferase family genes and systematically integrated these modification patterns with tumor metabolism and immune microenvironment characteristics. Glycosylation score was also developed to quantify glycosylation modification patterns of individuals. As a result, two glycosylation modification patterns were identified, with distinct prognosis, metabolism, and immune microenvironment features. The glycosylation subtype A and cluster A were characterized by higher carbohydrates and amino acid metabolism activity, higher levels of infiltrating cells, and poor prognosis, whereas an opposite modification pattern was observed in glycosylation subtype B and cluster B. In addition, a high glycosylation score is closer to a microenvironment characterized by chronic inflammation, immunosuppression, and tumor promotion. Following analysis and validation, the glycosylation score was a reliable and independent prognostic index. More importantly, the glycosylation score influenced the response to immunotherapy, chemotherapy, or targeted therapy, which provided a novel insight into promoting personalized therapy in the future and may contribute to developing novel therapeutic drugs or exploring promising drug combination therapy strategies.

Knockdown of RSPH14 inhibits proliferation, migration, and invasion and promotes apoptosis of hepatocellular carcinoma via RelA

Background

High RSPH14 expression appears to be related to poor prognosis of hepatocellular carcinoma (HCC). This study aimed to investigate the possible roles of RSPH14 in the proliferation, apoptosis, and invasion of HCC cells.

Methods

The UALCAN database and Kaplan–Meier Plotter were used to evaluate the expression level and prognostic role of RSPH14 in HCC. Lentiviral vectors containing shRNA against RSPH14 were constructed to transfect the BEL-7404 and SMMC-7721 HCC cell lines. Cell proliferation was investigated by BrdU, MTT, and colony-formation assays. Apoptosis was detected using flow cytometry. Cell migration and invasion were evaluated using the scratch wound-healing and Transwell assays. Immunohistochemistry and western blot were used to determine the expression levels of the proteins. The function of RSPH14 in vivo was evaluated using a xenograft mouse model.

Results

The expression of RSPH14 was higher in HCC tumor tissues than in adjacent normal tissues and was closely related to unfavorable prognostic factors and poorer survival (all P < 0.05). Knockdown of RSPH14 inhibited the cell proliferation, migration, and invasion of HCC cells and promoted apoptosis (all P < 0.05). Knockdown of RSPH14 inhibited tumor growth in vivo (P < 0.05). RSPH14 knockdown led to decreased expression of RelA (NF-κBp65), CDH2, and AKT1, thereby affecting the functions of the HCC cells (all P < 0.05). RelA overexpression could abate the inhibitory effect of BEL-7404 cell proliferation caused by RSPH14 depletion.

Conclusion

Knockdown of RSPH14 could decrease cell proliferation, migration, and invasion and increase apoptosis of HCC cells by inhibiting RelA expression. RSPH14 could be a new treatment target for HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02515-z.

Cytosolic O-GlcNAcylation and PNG1 maintain Drosophila gut homeostasis by regulating proliferation and apoptosis

Tissue homeostasis requires a delicate balance between stem cell self-renewal, proliferation, and differentiation. Essential to this process is glycosylation, with both intra-and extra-cellular glycosylation being required for stem cell homeostasis. However, it remains unknown how intracellular glycosylation, O-GlcNAcylation, interfaces with cellular components of the extracellular glycosylation machinery, like the cytosolic N-glycanase NGLY1. In this study, we utilize the Drosophila gut and uncover a pathway in which O-GlcNAcylation cooperates with the NGLY1 homologue PNG1 to regulate proliferation in intestinal stem cells (ISCs) and apoptosis in differentiated enterocytes. Further, the CncC antioxidant signaling pathway and ENGase, an enzyme involved in the processing of free oligosaccharides in the cytosol, interact with O-GlcNAc and PNG1 through regulation of protein aggregates to contribute to gut maintenance. These findings reveal a complex coordinated regulation between O-GlcNAcylation and the cytosolic glycanase PNG1 critical to balancing proliferation and apoptosis to maintain gut homeostasis.

Understanding glycosylation is of great importance as changes in both intra- and extra-cellular glycosylation have been well documented in diseases. However, it remains relatively unclear how intracellular glycosylation, O-GlcNAcylation, interfaces with the cellular machinery of extracellular glycosylation. In this study, we seek to understand how coordination between a cytosolic N-glycanase, NGLY1, and intracellular glycosylation, is utilized during stem cell proliferation. Using the Drosophila gut as a model system, our data showed O-GlcNAcylation and the Drosophila homologue of NGY1, PNG1, have key roles in both progenitor and differentiated cells that contribute to tissue homeostasis. Further, the CncC antioxidant signaling pathway and ENGase, an enzyme involved in the processing of free oligosaccharides in the cytosol, interact with O-GlcNAc and PNG1 through regulation of protein aggregates to contribute to gut maintenance. Our study suggests that alterations in O-GlcNAc and NGLY1 could be future targets utilized as therapeutics for nutrient-sensitive stem cell-derived diseases such as cancer.

Anandamide-Modulated Changes in Metabolism, Glycosylation Profile and Migration of Metastatic Melanoma Cells

Simple Summary

Anandamide (AEA) belongs to the group of endocannabinoids and possesses various regulatory properties in physiological as well as pathological processes occurring in the organism. In this research some basic biological tests were applied to investigate AEA-induced changes in cell metabolism and motility, as well as advanced biophysical methods for the determination of the differences in the cell glycosylation profile on a highly dangerous model of melanoma skin cancer, for which an effective therapy is not yet available. Our research suggests that anandamide treatment of metastatic melanoma cells increases the cell metabolism which leads to the reduction in the metastatic potential of cells in terms of the cell glycosylation profile and cell migration. In the view of our research, it can be presumed that anandamide usage in the combined therapy of advanced melanoma would be an advantage for the patient.

Abstract

An effective therapy for advanced melanoma, a skin cancer with the highest mortality, has not yet been developed. The endocannabinoid system is considered to be an attractive target for cancer treatment. The use of endocannabinoids, such as anandamide (AEA), is considered to be much greater than as a palliative agent. Thus, we checked its influence on various signaling pathways in melanoma cells. Our investigation was performed on four commercial cell lines derived from different progression stages (radial WM35 and vertical WM115 growth phases, lymph node WM266-4 metastasis, solid tumor A375-P metastasis). Cell viability, glucose uptake, quantification of reactive oxygen species production, expression of selected genes encoding glycosyltransferases, quantification of glycoproteins production and changes in the glycosylation profile and migration, as well as in cell elastic properties were analyzed. The cell glycosylation profile was investigated using the biophysical profiling method—the quartz crystal microbalance with dissipation monitoring (QCM-D). Anandamide treatment of only metastatic cells resulted in: an increase in the cell metabolism, a decrease in GFAT-1 and DPM1 expression, followed by a decrease in L1-CAM glycoprotein production, which further influenced the reduction in the cell glycosylation profile and migration. Considering our results, AEA usage is highly recommended in the combined therapy of advanced melanoma.

O-GlcNAcylation regulation of cellular signaling in cancer

O-GlcNAcylation is a post-translational modification occurring on serine/threonine residues of nuclear and cytoplasmic proteins, mediated by the enzymes OGT and OGA which catalyze the addition or removal of the UDP-GlcNAc moieties, respectively. Structural changes brought by this modification lead to alternations of protein stability, protein-protein interactions, and phosphorylation. Importantly, O-GlcNAcylation is a nutrient sensor by coupling nutrient sensing with cellular signaling. Elevated levels of OGT and O-GlcNAc have been reported in a variety of cancers and has been linked to regulation of multiple cancer signaling pathways. In this review, we discuss the most recent findings on the role of O-GlcNAcylation as a metabolic sensor in signaling pathways and immune response in cancer.

Exploring the Molecular Mechanism of lncRNA-miRNA-mRNA Networks in Non-Syndromic Cleft Lip with or without Cleft Palate

Background

Non-syndromic cleft lip with or without cleft palate (NSCL/P) is a common craniofacial birth defect. Growing evidence has demonstrated the competing endogenous RNA (ceRNA) hypothesis has played a role in the pathogenesis of NSCL/P. Here, we identified the important lncRNAs in NSCL/P and constructed a ceRNA regulatory network to predict their underlying functional mechanism.

Methods

Total RNA isolated from the peripheral blood samples were analyzed by the Human Clariom D Affymetrix platform and differentially expressed genes (DEGs) were identified. Using the limma package in R software, DEGs in the expression profile of GSE42589 were identified from Gene Expression Omnibus (GEO) database. Co-differentially expressed lncRNAs (co-DElncRNAs) were used to predict the microRNAs that may bind to them. Co-differentially expressed mRNAs (co-DEmRNAs) were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. The hub genes were screened using the cytohubba plug-in in Cytoscape. A ceRNA network was built to investigate the molecular mechanism underlying the etiology of NSCL/P. The expression levels of lncRNAs, miRNAs, and mRNAs in the network were assessed by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

We found 116 DElncRNAs and 2955 DEmRNAs from the GSE42589 dataset, and 2626 DElncRNAs and 2771 DEmRNAs from the Human Clariom D gene chip. A network of co-DEmRNAs containing 3712 edges and 621 nodes were identified by PPI analysis. A ceRNA regulatory network comprising lncRNA USP17L6P, hsa-miR-449c-5p, and MYC was established. qRT-PCR results revealed significantly lower expression levels of lncRNA USP17L6P and c-Myc in NSCL/P tissues, while the expression level of hsa-miR-449c-5p was higher as compared to control samples (p < 0.05).

Conclusion

The identified lncRNAs and the established ceRNA regulatory network provide novel insight into the pathogenesis of NSCL/P, therefore hold great promise in NSCL/P management in clinical practice.

Emerging roles of N-linked glycosylation in brain physiology and disorders

N-linked glycosylation is a complex, co- and post-translational series of events that connects metabolism to signaling in almost all cells. Metabolic assembly of N-linked glycans spans multiple cellular compartments, and early N-linked glycan biosynthesis is a central mediator of protein folding and the unfolded protein response (UPR). In the brain, N-linked glycosylated proteins participate in a myriad of processes, from electrical gradients to neurotransmission. However, it is less clear how perturbations in N-linked glycosylation impact and even potentially drive aspects of neurological disorders. In this review, we discuss our current understanding of the metabolic origins of N-linked glycans in the brain, their role in modulating neuronal function, and how aberrant N-linked glycosylation can drive neurological disorders.

Role and Function of O-GlcNAcylation in Cancer

Simple Summary

Despite the rapid advancement in immunotherapy and targeted agents, many patients diagnosed with cancer have poor prognosis with dismal overall survival. One of the key hallmarks of cancer is the ability of cancer cells to reprogram their energy metabolism. O-GlcNAcylation is an emerging potential mechanism for cancer cells to induce proliferation and progression of tumor cells and resistance to chemotherapy. This review summarizes the mechanism behind O-GlcNAcylation and discusses the role of O-GlcNAcylation, including its function with receptor tyrosine kinase and chemo-resistance in cancer, and immune response to cancer and as a prognostic factor. Further pre-clinical studies on O-GlcNAcylation are warranted to assess the clinical efficacy of agents targeting O-GlcNAcylation.

Abstract

Cancer cells are able to reprogram their glucose metabolism and retain energy via glycolysis even under aerobic conditions. They activate the hexosamine biosynthetic pathway (HBP), and the complex interplay of O-linked N-acetylglucosaminylation (O-GlcNAcylation) via deprivation of nutrients or increase in cellular stress results in the proliferation, progression, and metastasis of cancer cells. Notably, cancer is one of the emerging diseases associated with O-GlcNAcylation. In this review, we summarize studies that delineate the role of O-GlcNAcylation in cancer, including its modulation in metastasis, function with receptor tyrosine kinases, and resistance to chemotherapeutic agents, such as cisplatin. In addition, we discuss the function of O-GlcNAcylation in eliciting immune responses associated with immune surveillance in the tumor microenvironment. O-GlcNAcylation is increasingly accepted as one of the key players involved in the activation and differentiation of T cells and macrophages. Finally, we discuss the prognostic role of O-GlcNAcylation and potential therapeutic agents such as O-linked β-N-acetylglucosamine-transferase inhibitors, which may help overcome the resistance mechanism associated with the reprogramming of glucose metabolism.

Phenotypic changes on central nervous system (CNS) tumor cell lines cultured in vitro 2D and 3D models and treated with cisplatin

Despite aggressive therapy, most patients with brain tumors present disease relapse due to the cellular and molecular nature of these tumors. One of the models that best explains the heterogeneity observed in CNS tumors is the presence of cancer stem cells (CSCs). In this paper, we evaluated platinum-based response in brain tumor U-87 MG, LN-18, and KELLY cell lines cultured in monolayer (2D) and neurosphere (CSC enrichment- 3D) models. We evaluated mRNA expression of heat shock proteins (HSPA1A, HSPB1, HSPA1AL, TRAP1, and HSPD1), and DNA repair gene ERCC1. Changes in cell cycle and glycosylation profile were assessed by flow cytometry. After treatment with cisplatin, we found that the mRNA expression of HSPs markedly increased in the U-87 MG and LN-18 neurosphere cells. In KELLY monolayer cells, cisplatin induced upregulation of all genes. In KELLY neurosphere cells, only the HSPA1A, HSPB1, TRAP1, and HSPD1 genes were upregulated. The proportion of cells in the G₀/G₁ phase was significantly higher in U-87 MG neurosphere cisplatin-treated cells. A trend towards a greater proportion of cells in the S phase of U-87 MG monolayer cisplatin-treated cells was also observed. On the other hand, a significant decrease in the number of cells in the S phase and an increase in G₂/M was observed in LN-18 monolayer cisplatin-treated cells. Glycosylation analysis using lectins showed a higher surface binding for PNA in the U-87 MG treated monolayer and a lower binding for Concanavalin A in the treated neurospheres. The binding of Isolectin GS-IB4, GSII, and SBA in KELLY monolayer cisplatin-treated cells was lower whereas the proportion of cells labeled with Concanavalin A was higher. In the KELLY neurosphere cisplatin-treated cells, the binding of Concanavalin A was lower than nontreated cells. Thus, our findings strongly supported the idea that definitions of phenotypic characteristics may help to establish better therapeutic strategies for brain tumors.

The remodel of the "central dogma": a metabolomics interaction perspective

BACKGROUND

In 1957, Francis Crick drew a linear diagram on a blackboard. This diagram is often called the "central dogma." Subsequently, the relationships between different steps of the "central dogma" have been shown to be considerably complex, mostly because of the emerging world of small molecules. It is noteworthy that metabolites can be generated from the diet through gut microbiome metabolism, serve as substrates for epigenetic modifications, destabilize DNA quadruplexes, and follow Lamarckian inheritance. Small molecules were once considered the missing link in the "central dogma"; however, recently they have acquired a central role, and their general perception as downstream products has become reductionist. Metabolomics is a large-scale analysis of metabolites, and this emerging field has been shown to be the closest omics associated with the phenotype and concomitantly, the basis for all omics.

AIM OF REVIEW

Herein, we propose a broad updated perspective for the flux of information diagram centered in metabolomics, including the influence of other factors, such as epigenomics, diet, nutrition, and the gut- microbiome.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Metabolites are the beginning and the end of the flux of information.

Chlorogenic Acid Inhibits Human Glioma U373 Cell Progression via Regulating the SRC/MAPKs Signal Pathway: Based on Network Pharmacology Analysis

Introduction

Chlorogenic acid (CGA) is a type of polyphenolic substance that is widely extracted from many traditional Chinese medicines (eg, Lonicera japonica Thunb, Eucommia ulmoides Oliver) and exhibits a wide range of anti-tumor effects. However, the potential molecular mechanisms of CGA in glioma U373 cells remain unclear.

Methods

Network pharmacology analysis was used to explore the potential therapeutic targets of CGA in glioma. Human glioma U373 cells were treated with different concentrations of CGA for 24 h. CCK-8 assays were used to detect the inhibitory rate of cell growth. Annexin V-FITC/PI staining and Hoechst 33342 staining were used to detect apoptosis. PI staining was used to investigate cell-cycle progression. Wound healing assays and transwell assays were used to detect the cell migration and invasion, respectively. Western blotting and immunohistochemistry were used to measure protein levels in vitro and in vivo.

Results

The proliferation of U373 cells was significantly inhibited by CGA in a dose- and time-dependent manner. CGA significantly arrested the cell cycle of U373 cells in the G2/M phase and induced apoptosis. Moreover, CGA significantly suppressed the migration and invasion of U373 cells. Additionally, we found that CGA inhibited the growth of U373 cells in vivo. Furthermore, network pharmacology analysis suggested that the anti-tumor effects of CGA on U373 cells were associated with the down-regulation of the SRC/MAPKs signaling pathway.

Discussion

The present study indicated that CGA had anti-glioma effects on U373 cells by down-regulating SRC/MAPKs signal pathway.

Research progress on O-GlcNAcylation in the occurrence, development, and treatment of colorectal cancer

For a long time, colorectal cancer (CRC) has been ranked among the top cancer-related mortality rates, threatening human health. As a significant post-translational modification, O-GlcNAcylation plays an essential role in complex life activities. Related studies have found that the occurrence, development, and metastasis of CRC are all related to abnormal O-GlcNAcylation and participate in many critical biological processes, such as gene transcription, signal transduction, cell growth, and differentiation. Recently, nucleotide sugar analogs, tumor-specific carbohydrate vaccine, SIRT1 longevity gene, dendritic cells as targets, and NOTCH gene have become effective methods to induce antitumor therapy. Not long ago, checkpoint kinase 1 and checkpoint kinase 2 were used as therapeutic targets for CRC, but there are still many problems to be solved. With an in-depth study of protein chip, mass spectrometry, chromatography, and other technologies, O-GlcNAcylation research will accelerate rapidly, which may provide new ideas for the research and development of antitumor drugs and the discovery of new CRC diagnostic markers.

O-GlcNAc Transferase - An Auxiliary Factor or a Full-blown Oncogene?

The β-linked N-acetyl-d-glucosamine (GlcNAc) is a posttranslational modification of serine and threonine residues catalyzed by the enzyme O-GlcNAc transferase (OGT). Increased OGT expression is a feature of most human cancers and inhibition of OGT decreases cancer cell proliferation. Antiproliferative effects are attributed to posttranslational modifications of known regulators of cancer cell proliferation, such as MYC, FOXM1, and EZH2. In general, OGT amplifies cell-specific phenotype, for example, OGT overexpression enhances reprogramming efficiency of mouse embryonic fibroblasts into stem cells. Genome-wide screens suggest that certain cancers are particularly dependent on OGT, and understanding these addictions is important when considering OGT as a target for cancer therapy. The O-GlcNAc modification is involved in most cellular processes, which raises concerns of on-target undesirable effects of OGT-targeting therapy. Yet, emerging evidence suggest that, much like proteasome inhibitors, specific compounds targeting OGT elicit selective antiproliferative effects in cancer cells, and can prime malignant cells to other treatments. It is, therefore, essential to gain mechanistic insights on substrate specificity for OGT, develop reagents to more specifically enrich for O-GlcNAc-modified proteins, identify O-GlcNAc "readers," and develop OGT small-molecule inhibitors. Here, we review the relevance of OGT in cancer progression and the potential targeting of this metabolic enzyme as a putative oncogene.

Functional Analysis of O-GlcNAcylation in Cancer Metastasis

One common and reversible type of post-translational modification (PTM) is the addition of O-linked β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation), and its dynamic balance is controlled by O-GlcNAc transferase (OGT) and glycoside hydrolase O-GlcNAcase (OGA) through the addition or removal of O-GlcNAc groups. A large amount of research data confirms that proteins regulated by O-GlcNAcylation play a pivotal role in cells. In particularly, imbalanced levels of OGT and O-GlcNAcylation have been found in various types of cancers. Recently, increasing evidence shows that imbalanced O-GlcNAcylation directly or indirectly impacts the process of cancer metastasis. This review summarizes the current understanding of the influence of O-GlcNAc-proteins on the regulation of cancer metastasis. It will provide a theoretical basis to further elucidate of the molecular mechanisms underlying cancer emergence and progression.

Resistance to paclitaxel induces glycophenotype changes and mesenchymal-to-epithelial transition activation in the human prostate cancer cell line PC-3

The development of the multidrug resistance phenotype is one of the major challenges faced in the treatment of cancer. The multidrug resistance phenotype is characterized by cross-resistance to drugs with different chemical structures and mechanisms of action. In this work, we hypothesized that the acquisition of resistance in cancer is accompanied by activation of the epithelial-to-mesenchymal transition process, where the tumor cell acquires a more mobile and invasive phenotype; a fundamental step in tumor progression and in promoting the invasion of other organs and tissues. In addition, it is known that atypical glycosylations are characteristic of tumor cells, being used as biomarkers. We believe that the acquisition of the multidrug resistance phenotype and the activation of epithelial-to-mesenchymal transition provoke alterations in the cell glycophenotype, which can be used as glycomarkers for chemoresistance and epithelial-to-mesenchymal transition processes. Herein, we induced the multidrug resistance phenotype in the PC-3 human prostate adenocarcinoma line through the continuous treatment with the drug paclitaxel. Our results showed that the induced cell multidrug resistance phenotype (1) acquired a mixed profile between epithelial and mesenchymal phenotypes and (2) modified the glycophenotype, showing an increase in the level of sialylation and in the number of branched glycans. Both mechanisms are described as indicators of poor prognosis.

Recognition Pattern, Functional Mechanism and Application of Chitin and Chitosan Oligosaccharides in Sustainable Agriculture

Background:

Application of chitin attracts much attention in the past decades as the second abundant polysaccharides in the world after cellulose. Chitin oligosaccharides (CTOS) and its deacetylated derivative chitosan oligosaccharides (COS) were shown great potentiality in agriculture by enhancing plant resistance to abiotic or biotic stresses, promoting plant growth and yield, improving fruits quality and storage, etc. Those applications have already served huge economic and social benefits for many years. However, the recognition mode and functional mechanism of CTOS and COS on plants have gradually revealed just in recent years.

Objective:

Recognition pattern and functional mechanism of CTOS and COS in plant together with application status of COS in agricultural production will be well described in this review. By which we wish to promote further development and application of CTOS and COS–related products in the field.

MicroRNA-10a promotes epithelial-to-mesenchymal transition and stemness maintenance of pancreatic cancer stem cells via upregulating the Hippo signaling pathway through WWC2 inhibition

MicroRNAs (miRNAs)-mediated cancer stem cells (CSCs) have drawn wide attention. This study aimed to probe the role of miR-10a in epithelial-mesenchymal transition (EMT) and stemness maintenance of pancreatic CSCs (PCSCs). Differentially expressed miRs and genes in pancreatic cancer (PC) were predicted via an online database, and the miR-10a and WW and C2 domain containing 2 (WWC2) expression were identified via a comparative study in PC and pancreatitis tissues. PCNCs were isolated and identified, and then the functional roles of miR-10a and WWC2 in proliferation, invasion, migration, self-renewal, colony formation abilities, EMT, and stemness maintenance of PCNCs were determined. The effects of miR-10a on tumor growth in vivo were studied by performing a xenograft tumor in nude mice. Consequently, miR-10a was highly expressed while WWC2 was lowly expressed in PC tissues. miR-10a could target WWC2 expression. miR-10a inhibition reduced EMT and stemness maintenance of PCSCs via enhancing WWC2 expression. The in vitro results were reproduced in in vivo studies. miR-10a promoted EMT and stemness maintenance of PCSCs via activating the Hippo signaling pathway. Our study provided evidence that miR-10a inhibition reduced EMT and stemness maintenance of PCSCs via upregulating WWC2 expression and inhibiting the Hippo signaling pathway.

A non-proliferative role of pyrimidine metabolism in cancer

Background

Nucleotide metabolism is a critical pathway that generates purine and pyrimidine molecules for DNA replication, RNA synthesis, and cellular bioenergetics. Increased nucleotide metabolism supports uncontrolled growth of tumors and is a hallmark of cancer. Agents inhibiting synthesis and incorporation of nucleotides in DNA are widely used as chemotherapeutics to reduce tumor growth, cause DNA damage, and induce cell death. Thus, the research on nucleotide metabolism in cancer is primarily focused on its role in cell proliferation. However, in addition to proliferation, the role of purine molecules is established as ligands for purinergic signals. However, so far, the role of the pyrimidines has not been discussed beyond cell growth.

Scope of the review

In this review we present the key evidence from recent pivotal studies supporting the notion of a non-proliferative role for pyrimidine metabolism (PyM) in cancer, with a special focus on its effect on differentiation in cancers from different origins.

Major conclusion

In leukemic cells, the pyrimidine catabolism induces terminal differentiation toward monocytic lineage to check the aberrant cell proliferation, whereas in some solid tumors (e.g., triple negative breast cancer and hepatocellular carcinoma), catalytic degradation of pyrimidines maintains the mesenchymal-like state driven by epithelial-to-mesenchymal transition (EMT). This review further broadens this concept to understand the effect of PyM on metastasis and, ultimately, delivers a rationale to investigate the involvement of the pyrimidine molecules as oncometabolites. Overall, understanding the non-proliferative role of PyM in cancer will lead to improvement of the existing antimetabolites and to development of new therapeutic options.

Endothelial Cells (ECs) Metabolism: A Valuable Piece to Disentangle Cancer Biology

Effective therapies to fight cancer should not be focused specifically on cancer cells, but it should consider the various components of the TME. Non-cancerous cells cooperate with cancer cells by sharing signaling and organic molecules, accounting for cancer progression. Most of the anti-angiogenic therapy clinically approved for the treatment of human diseases relies on targeting vascular endothelial growth factor (VEGF) signaling pathway. Unexpectedly and unfortunately, the results of anti-angiogenic therapies in the treatment of human diseases are not so effective, showing an insufficient efficacy and resistance.This chapter will give some insights on showing that targeting endothelial cell metabolism is a missing piece to revolutionize cancer therapy. Only recently endothelial cell (EC) metabolism has been granted as an important inducer of angiogenesis. Metabolic studies in EC demonstrated that targeting EC metabolism can be an alternative to overcome the failure of anti-angiogenic therapies. Hence, it is urgent to increase the knowledge on how ECs alter their metabolism during human diseases, in order to open new therapeutic perspectives in the treatment of pathophysiological angiogenesis, as in cancer.

Transcriptomic profiling of gamma ray induced mutants from the CGL1 human hybrid cell system reveals novel insights into the mechanisms of radiation-induced carcinogenesis

BACKGROUND

Somatic cell hybrid systems generated by combining cancerous with non-cancerous cells provide useful model systems to study neoplastic transformation. Combined with recent advances in omics-based technologies, novel molecular signatures that drive radiation-induced carcinogenesis can be analyzed at an exceptional global level.

METHODS

Here, we present a complete whole-transcriptome analysis of gamma-induced mutants (GIM) and gamma irradiated control (CON) segregants isolated from the CGL1 (HeLa x normal fibroblast) human hybrid cell-system exposed to high doses of radiation. Using the Human Transcriptome Array 2.0 microarray technology and conservative discrimination parameters, we have elucidated 1067 differentially expressed genes (DEGs) between tumorigenic and non-tumorigenic cells.

RESULTS

Gene ontology enrichment analysis revealed that tumorigenic cells demonstrated shifts in extracellular matrix (ECM) and cellular adhesion profiles, dysregulation of cyclic AMP (cAMP) signaling, and alterations in nutrient transport and cellular energetics. Furthermore, putative upstream master regulator analysis demonstrated that loss of TGFβ1 signaling due to reduced SMAD3 expression is involved in radiation-induced carcinogenesis.

CONCLUSIONS

Taken together, this study presents novel insights into specific gene expression and pathway level differences that contribute to radiation-induced carcinogenesis in a human cell-based model. This global transcriptomic analysis and our published tumor suppressor gene deletion loci analyses will allow us to identify and functionally test candidate nexus upstream tumor suppressor genes that are deleted or silenced after exposure to radiation.

Podoplanin-Expressing Macrophages Promote Lymphangiogenesis and Lymphoinvasion in Breast Cancer

Among mammary tumor-infiltrating immune cells, the highest expression of podoplanin (PDPN) is found in a subset of tumor-associated macrophages (TAMs). We hereby demonstrate that PDPN is involved in the attachment of this TAM subset to lymphatic endothelial cells (LECs). Mechanistically, the binding of PDPN to LEC-derived galectin 8 (GAL8) in a glycosylation-dependent manner promotes the activation of pro-migratory integrin β1. When proximal to lymphatics, PDPN-expressing macrophages (PoEMs) stimulate local matrix remodeling and promote vessel growth and lymphoinvasion. Anti-integrin β1 blockade, macrophage-specific Pdpn knockout, or GAL8 inhibition impairs TAM adhesion to LECs, restraining lymphangiogenesis and reducing lymphatic cancer spread. In breast cancer patients, association of PoEMs with tumor lymphatic vessels correlates with incidences of lymph node and distant organ metastasis.

Fueling the fire: emerging role of the hexosamine biosynthetic pathway in cancer

Altered metabolism and deregulated cellular energetics are now considered a hallmark of all cancers. Glucose, glutamine, fatty acids, and amino acids are the primary drivers of tumor growth and act as substrates for the hexosamine biosynthetic pathway (HBP). The HBP culminates in the production of an amino sugar uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) that, along with other charged nucleotide sugars, serves as the basis for biosynthesis of glycoproteins and other glycoconjugates. These nutrient-driven post-translational modifications are highly altered in cancer and regulate protein functions in various cancer-associated processes. In this review, we discuss recent progress in understanding the mechanistic relationship between the HBP and cancer.

Emerging role of glycosylation in the polarization of tumor-associated macrophages

Tumors are formed by several cell types interacting in a complex environment of soluble and matrix molecules. The crosstalk between the cells and extracellular components control tumor fate. Macrophages are highly plastic and diverse immune cells that are known to be key regulators of this complex network, which is mostly because they can adjust their metabolism and reprogram their phenotype and effector function. Here, we review the studies that disclose the central role of metabolism and tumor microenvironment in shaping the phenotype and function of macrophages, highlighting the importance of the hexosamine biosynthetic pathway. We further discuss growing evidence of nutrient-sensitive protein modifications such as O-GlcNAcylation and extracellular glycosylation in the function and polarization of tumor-associated macrophages.

Emerging Anticancer Activity of Candidal Glucoseamine-6-Phosphate Synthase Inhibitors upon Nanoparticle-Mediated Delivery

Numerous glutamine analogues have been reported as irreversible inhibitors of the glucosamine-6-phosphate (GlcN-6-P) synthase in pathogenic Candida albicans in the last 3.5 decades. Among the reported inhibitors, the most effective N³-(4-methoxyfumaroyl)-l-2,3-diaminopropanoic acid (FMDP) has been extensively studied in order to develop its more active analogues. Several peptide-FMDP conjugates were tested to deliver FMDP to its subcellularly located GlcN-6-P synthase target. However, the rapid development of fungal resistance to FMDP-peptides required development of different therapeutic approaches to tackle antifungal resistance. In the current state of the global antifungal resistance, subcellular delivery of FMDP via free diffusion or endocytosis has become crucial. In this study, we report on in vitro nanomedical applications of FMDP and one of its ketoacid analogues, N³- trans-4-oxo-4-phenyl-2-butenoyl-l-2,3-diaminopropanoic acid (BADP). FMDP and BADP covalently attached to polyethylene glycol-coated iron oxide/silica core-shell nanoparticles are tested against intrinsically multidrug-resistant C. albicans. Three different human cancer cell lines potentially overexpressing the GlcN-6-P synthase enzyme are tested to demonstrate the immediate inhibitory effects of nanoparticle conjugates against mammalian cells. It is shown that nanoparticle-mediated delivery transforms FMDP and BADP into strong anticancer agents by inhibiting the growth of the tested cancer cells, whereas their anti-Candidal activity is decreased. This study discusses the emerging inhibitory effect of the FMDP/BADP-nanoparticle conjugates based on their cellular internalization efficiency and biocompatibility.

Hypoxia and serum deprivation induces glycan alterations in triple negative breast cancer cells

Triple negative breast cancer (TNBC) is a major global public health problem. The lack of targeted therapy and the elevated mortality evidence the need for better knowledge of the tumor biology. Hypoxia and aberrant glycosylation are associated with advanced stages of malignancy, tumor progression and treatment resistance. Importantly, serum deprivation regulates the invasive phenotype and favors TNBC cell survival. However, in TNBC, the role of hypoxia and serum deprivation in the regulation of glycosylation remains largely unknown. The effects of hypoxia and serum deprivation on the expression of glycosyltransferases and glycan profile were evaluated in the MDA-MB-231 cell line. We showed that the overexpression of HIF-1α was accompanied by acquisition of epithelial-mesenchimal transition features. Significant upregulation of fucosyl- and sialyltransferases involved in the synthesis of tumor-associated carbohydrate antigens was observed together with changes in fucosylation and sialylation detected by Aleuria aurantia lectin and Sambucus nigra agglutinin lectin blots. Bioinformatic analysis further indicated a mechanism by which HIF-1α can regulate ST3GAL6 expression and the relationship within the intrinsic characteristics of TNBC tumors. In conclusion, our results showed the involvement of hypoxia and serum deprivation in glycosylation profile regulation of TNBC cells triggering breast cancer aggressive features and suggesting glycosylation as a potential diagnostic and therapeutic target.

Hexosamine Biosynthetic Pathway and Glycosylation Regulate Cell Migration in Melanoma Cells

The Hexosamine Biosynthetic Pathway (HBP) is a branch of glycolysis responsible for the production of a key substrate for protein glycosylation, UDP-GlcNAc. Cancer cells present altered glucose metabolism and aberrant glycosylation, pointing to alterations on HBP. Recently it was demonstrated that HBP influences many aspects of tumor biology, including the development of metastasis. In this work we characterize HBP in melanoma cells and analyze its importance to cellular processes related to the metastatic phenotype. We demonstrate that an increase in HBP flux, as well as increased O-GlcNAcylation, leads to decreased cell motility and migration in melanoma cells. In addition, inhibition of N- and O-glycosylation glycosylation reduces cell migration. High HBP flux and inhibition of N-glycosylation decrease the activity of metalloproteases 2 and 9. Our data demonstrates that modulation of HBP and different types of glycosylation impact cell migration.

Bittersweet tumor development and progression: Emerging roles of epithelial plasticity glycosylations

Altered metabolism is one of the hallmarks of cancer. The best-known cancer metabolic anomaly is an increase in aerobic glycolysis, which generates ATP and other basic building blocks, such as nucleotides, lipids, and proteins to support tumor cell growth and survival. Epithelial plasticity (EP) programs such as the epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) are evolutionarily conserved processes that are essential for embryonic development. EP also plays an important role during tumor progression toward metastasis and treatment resistance, and new roles in the acceleration of tumorigenesis have been found. Recent evidence has linked EMT-related transcriptomic alterations with metabolic reprogramming in cancer cells, which include increased aerobic glycolysis. More recent studies have revealed a novel connection between EMT and altered glycosylation in tumor cells, in which EMT drives an increase in glucose uptake and flux into the hexosamine biosynthetic pathway (HBP). The HBP is a side-branch pathway from glycolysis which generates the end product uridine-5'-diphosphate-N-acetylglucosamine (UDP-GlcNAc). A key downstream utilization of UDP-GlcNAc is for the post-translational modification O-GlcNAcylation which involves the attachment of the GlcNAc moiety to Ser/Thr/Asn residues of proteins. Global changes in protein O-GlcNAcylation are emerging as a general characteristic of cancer cells. In our recent study, we demonstrated that the EMT-HBP-O-GlcNAcylation axis drives the O-GlcNAcylation of key proteins such as c-Myc, which previous studies have shown to suppress oncogene-induced senescence (OIS) and contribute to accelerated tumorigenesis. Here, we review the HBP and O-GlcNAcylation and their putative roles in driving EMT-related cancer processes with examples to illuminate potential new therapeutic targets for cancer.

Hexosamine pathway regulates StarD7 expression in JEG-3 cells

StarD7 is a lipid binding protein involved in the delivery of phosphatidylcholine to the mitochondria whose promoter is activated by Wnt/β-catenin signaling. Although the majority of glucose enters glycolysis, ~ 2-5% of it can be metabolized via the hexosamine biosynthetic pathway (HBP). Considering that HBP has been implicated in the regulation of β-catenin we explored if changes in glucose levels modulate StarD7 expression by the HBP in trophoblast cells. We found an increase in StarD7 as well as in β-catenin expression following high-glucose (25 mM) treatment in JEG-3 cells; these effects were abolished in the presence of HBP inhibitors. Moreover, since HBP is able to promote unfolded protein response (UPR) the protein levels of GRP78, Ire1α, calnexin, p-eIF2α and total eIF2α as well as XBP1 mRNA was measured. Our results indicate that a diminution in glucose concentration leads to a decrease in StarD7 expression and an increase in the UPR markers: GRP78 and Ire1α. Conversely, an increase in glucose is associated to high StarD7 levels and low GRP78 expression, phospho-eIF2α and XBP1 splicing, although Ire1α remains high when cells are restored to high glucose. Taken together these findings indicate that glucose modulates StarD7 and β-catenin expression through the HBP associated to UPR, suggesting the existence of a link between UPR and HBP in trophoblast cells. This is the first study reporting the effects of glucose on StarD7 in trophoblast cells. These data highlight the importance to explore the role of StarD7 in placenta disorders related to nutrient availability.

MicroRNA-206 regulates the epithelial-mesenchymal transition and inhibits the invasion and metastasis of prostate cancer cells by targeting Annexin A2

The present study investigated the molecular mechanism by which microRNA-206 (miR-206) targets Annexin A2 (ANXA2) expression and inhibits the invasion and metastasis of prostatic cancer cells through regulation of the epithelial-mesenchymal transition (EMT). Using bioinformatics analysis, miR-206 was identified as the most promising candidate miRNA that targeted ANXA2. Prostate tissue specimens from 60 patients with prostate cancer, 30 patients with metastatic prostate cancer and 20 patients with benign prostatic hyperplasia (BPH) were examined for ANXA2 protein expression by immunohistochemistry and western blotting and for miR-206 expression by reverse transcription-quantitative polymerase chain reaction. Additionally, human prostate cancer PC-3 cells were transfected with miR-206 mimics, miR-206 inhibitors or a negative control sequence, and expression of ANXA2, E-cadherin and N-cadherin was detected by western blotting. Transwell assays were performed to determine the effect of altered miR-206 expression on the invasive behavior of PC-3 cells. Bioinformatics analysis predicted complementary binding between miR-206 and ANXA2 mRNA. ANXA2 protein expression was detected in a significantly higher proportion of BPH tissues (95%, 19/20) when compared with prostate cancer tissues (51.7%, 31/60; P<0.05). Similarly, ANXA2 was expressed in a significantly higher proportion of metastatic prostate cancer samples than that of prostate cancer samples (P<0.05). Expression of miR-206 was higher than that of ANXA2 in prostate cancer samples, but lower in BPH samples. Inhibition of miR-206 expression in PC-3 cells upregulated ANXA2 and E-cadherin protein expression levels, downregulated N-cadherin and vimentin, and promoted cell invasion in vitro. These data suggested that binding between miRNA-206 and ANXA2 mRNA may regulate EMT signaling, thereby suppressing the invasion and metastasis of prostatic cancer cells.

O-GlcNAc in cancer: An Oncometabolism-fueled vicious cycle

Cancer cells exhibit unregulated growth, altered metabolism, enhanced metastatic potential and altered cell surface glycans. Fueled by oncometabolism and elevated uptake of glucose and glutamine, the hexosamine biosynthetic pathway (HBP) sustains glycosylation in the endomembrane system. In addition, the elevated pools of UDP-GlcNAc drives the O-GlcNAc modification of key targets in the cytoplasm, nucleus and mitochondrion. These targets include transcription factors, kinases, key cytoplasmic enzymes of intermediary metabolism, and electron transport chain complexes. O-GlcNAcylation can thereby alter epigenetics, transcription, signaling, proteostasis, and bioenergetics, key 'hallmarks of cancer'. In this review, we summarize accumulating evidence that many cancer hallmarks are linked to dysregulation of O-GlcNAc cycling on cancer-relevant targets. We argue that onconutrient and oncometabolite-fueled elevation increases HBP flux and triggers O-GlcNAcylation of key regulatory enzymes in glycolysis, Kreb's cycle, pentose-phosphate pathway, and the HBP itself. The resulting rerouting of glucose metabolites leads to elevated O-GlcNAcylation of oncogenes and tumor suppressors further escalating elevation in HBP flux creating a 'vicious cycle'. Downstream, elevated O-GlcNAcylation alters DNA repair and cellular stress pathways which influence oncogenesis. The elevated steady-state levels of O-GlcNAcylated targets found in many cancers may also provide these cells with a selective advantage for sustained growth, enhanced metastatic potential, and immune evasion in the tumor microenvironment.

Drug resistance related to aberrant glycosylation in colorectal cancer

Colorectal cancer (CRC) is the fourth leading cause of cancer-related deaths in the world. Drug resistance of tumour cells remains the main challenge toward curative treatments efficiency. Several epidemiologic studies link emergence and recurrence of this cancer to metabolic disorders. Glycosylation that modifies more than 80% of human proteins is one of the most widepread nutrient-sensitive post-translational modifications. Aberrant glycosylation participates in the development and progression of cancer. Thus, some of these glycan changes like carbohydrate antigen CA 19-9 (sialyl Lewis a, sLea) or those found on carcinoembryonic antigen (CEA) are already used as clinical biomarkers to detect and monitor CRC. The current review highlights emerging evidences accumulated mainly during the last decade that establish the role played by altered glycosylations in CRC drug resistance mechanisms that induce resistance to apoptosis and activation of signaling pathways, alter drug absorption and metabolism, and led to stemness acquisition. Knowledge in this field of investigation could aid to the development of better therapeutic approaches with new predictive biomarkers and targets tied in with adapted diet.