Elucidating the role of the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) and its closest homolog-GALNT6 in mediating aberrant O-glycosylation associated with ovarian cancer dissemination
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PROVIDER: PRJNA414047 | ENA |
REPOSITORIES: ENA
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Project description:Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, thus understanding molecular changes associated with EOC progression could lead to the identification of essential therapeutic targets. Glycosylation is a post-translational modification (PTM) that participates in major pathophysiology events, including tumorigenesis. Aberrant mucin-type or O-glycosylation in cancer is frequently attributed to altered expression of different N-acetylgalactosaminyltransferases (GalNAc-Ts). We have previously identified the N-acetylgalactosaminyltransferase 3 (GALNT3) gene as a potential EOC oncogene, possibly implicated in aberrant O-glycosylation in EOC cells. Literature reports are suggestive for genetic and functional redundancy between different GalNAc-Ts, and our previous data were indicative for an induction of the GALNT6 expression upon GALNT3 suppression in EOC cells. Here we show that GALNT3 gene knockout (KO) in the A2780s EOC cells leads to strong GALNT6 upregulation. Moreover, A2780s cell migration, invasion, proliferation and cell cycle analysis were significantly reduced in double GALNT3/T6 gene KO cells compared to single GALNT3 gene KO. Furthermore, MUC1 expression was downregulated in both GALNT3 KO and GALNT3/6 KO, with a more prominent decrease observed in the double KO clone. In vivo studies supported the observed functional redundancy imposed by GALNT6, as animals injected with double GALNT3/T6 KO EOC cell clones displayed a significant increase in survival rates compared to those injected with the control and the GALNT3 KO clones. Collectively our data strongly suggest for possible functional redundancy of the two GalNAc-Ts (GALNT3 and T6) in EOC, with the perspective to use both of these genes as EOC markers and/or therapeutic targets.
2019-05-07 | GSE104861 | GEO
Project description:GalNAc-transferase (GalNAc-T) isoforms modify distinct subsets of the O-glycoproteome and GalNAc-type O-glycosylation is found on most proteins trafficking through the secretory pathway in metazoan cells. The O-glycoproteome is regulated by up to 20 polypeptide GalNAc-Ts and the contributions and biological functions of individual GalNAc-Ts are poorly understood. Here, we used a zinc-finger nuclease (ZFN)-directed knockout strategy to probe the contributions of the major GalNAc-Ts (GalNAc-T1 and T2) in liver cells, and explore how the GalNAc-T repertoire quantitatively affects the O-glycoproteome. We demonstrate that the majority of the O-glycoproteome is covered by redundancy, whereas distinct subsets of substrates are modified by non-redundant functions of GalNAc-T1 and T2. Differential transcriptomic analysis indicates that loss of function of a GalNAc-T induces specific transcriptional response. The non-redundant O-glycoproteome subsets for and the transcriptional responses for each isoform appeared to be related to different cellular processes, and for the GalNAc-T2 isoform supporting a role in lipid metabolism. The results demonstrate that GalNAc-Ts have non-redundant glycosylation functions, and that these may affect distinct cellular processes. The data provides a comprehensive resource for unique substrates for individual GalNAc-Ts. Our study provides a new view on the regulation of the O-glycoproteome, suggesting that the plurality of GalNAc-Ts arose to regulate distinct protein functions and cellular processes.
2015-09-30 | E-MTAB-3844 | biostudies-arrayexpress
Project description:Deconstruction of O-glycosylation – Polypeptide GalNAc-T Isoforms Direct Distinct Subsets of the O-Glycoproteome
| PRJEB10772 | ENA
Project description:Previously, we have identified the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that GALNT3 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in GALNT3 overexpression in serous epithelial ovarian cancer (EOC). Moreover, GALNT3 expression significantly correlated with shorter progression-free survival (PFS) periods in serous EOC patients with advanced disease. Knockdown of the GALNT3 expression in EOC cells led to sharp decrease of cell proliferation and induced S-phase cell cycle arrest. Additionally, GALNT3 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon GALNT3 suppression, while some tumor suppressor genes were induced. Moreover, GALNT3 downregulation was associated with reduced MUC1 protein expression in EOC cells, probably related to destabilization of the MUC1 protein due to lack of GALNT3 glycosylation activity.Taken together, our data are indicative for a strong oncogenic potential of the GALNT3 gene in advanced EOC and identify this transferase as a novel EOC biomarker and putative EOC therapeutic target. Our findings also suggest that GALNT3 overexpression might contribute to ovarian etiology through aberrant mucin O-glycosylation.
2014-05-22 | GSE52602 | GEO
Project description:Previously, we have identified the polypeptide N-acetylgalactosaminyltransferase 3 (GALNT3) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that GALNT3 is strongly overexpressed in both LMP and HG serous EOC tumors, thus suggesting that epigenetic mechanisms might be implicated in GALNT3 overexpression in serous epithelial ovarian cancer (EOC). Moreover, GALNT3 expression significantly correlated with shorter progression-free survival (PFS) periods in serous EOC patients with advanced disease. Knockdown of the GALNT3 expression in EOC cells led to sharp decrease of cell proliferation and induced S-phase cell cycle arrest. Additionally, GALNT3 suppression significantly inhibited EOC cell migration and invasion. Gene expression profiling and consecutive network and pathway analyses confirmed these findings, as numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, including EOC tumor invasion and metastasis, were found to be downregulated upon GALNT3 suppression, while some tumor suppressor genes were induced. Moreover, GALNT3 downregulation was associated with reduced MUC1 protein expression in EOC cells, probably related to destabilization of the MUC1 protein due to lack of GALNT3 glycosylation activity.Taken together, our data are indicative for a strong oncogenic potential of the GALNT3 gene in advanced EOC and identify this transferase as a novel EOC biomarker and putative EOC therapeutic target. Our findings also suggest that GALNT3 overexpression might contribute to ovarian etiology through aberrant mucin O-glycosylation. To better understand the molecular mechanisms of GALNT3 gene action in ovarian cancer cells, we employed the Agilent Whole Human Genome microarrays, containing ~ 44,000 genes to identify global gene expression changes upon GALNT3 suppression in A2780s cells. We compared the gene expression of the previously selected clone shRNA- GALNT3-knockdown clones 1 & 2 (sh-cl1 & sh-cl2) against the corresponding control (ctrl) clone. The microarray experiments were performed in duplicates, as four hybridizations were carried out for the GALNT3-suppressing cell clones against the corresponding control, using a fluorescent dye reversal (dye-swap) technique.
2014-05-22 | E-GEOD-52602 | biostudies-arrayexpress
Project description:Cancer metastasis requires the transient activation of cellular programs enabling dissemination and seeding in distant organs. Genetic, transcriptional and translational heterogeneity contributes to this dynamic process. Metabolic heterogeneity has also been observed, yet its role for cancer progression is less explored. Here, we discover that loss of phosphoglycerate dehydrogenase (PHGDH) potentiates metastatic dissemination. Specifically, we find that heterogeneous or low PHGDH expression in primary tumors of breast cancer patients is associated with decreased metastasis free survival time. In mice, circulating tumor cells and early metastatic lesions are enriched with PHGDH low cancer cells and silencing PHGDH in primary tumors increases metastasis formation. Mechanistically, PHGDH protein interacts with the glycolytic enzyme phosphofructokinase (PFK) and the loss of this interaction activates the hexosamine – sialic acid pathway, which provides precursors for protein glycosylation. Consequently, aberrant protein glycosylation including increased sialylation of integrin αvβ3 occurs, which potentiates cell migration and invasion. Inhibition of sialic acid metabolism counteracts the metastatic capacity of PHGDH low cancer cells. In conclusion, while the catalytic activity of PHGDH supports cancer cell proliferation, low PHGDH protein expression non-catalytically potentiates cancer dissemination and metastasis formation. Thus, the presence of PHDGH heterogeneity in primary tumors may be considered a sign of tumor aggressiveness.
2022-03-30 | GSE198380 | GEO
Project description:This laboratory focuses on the molecular mechanisms of neuropsychiatric and neurodegenerative disorders Our goal is to elucidate mechanisms by which regulated expression of proteoglycans and glycosylation-related genes contribute to neurodegenerative diseases involving the striatum. A number of studies have demonstrated that neural proteoglycans are involved structural organization of the striatum and formation of dopaminergic connections to and from the striatum. Several proteoglycans are also associated with neuronal regeneration and some have been shown to be components of filamentous inclusions found in neurodegenerative disorders. In addition, the localization and proper function of dopamine receptors, which are predominantly expressed in the striatum, are governed by N-linked glycosylation events. Huntingtonís Disease (HD), a progressive neurodegenerative disorder, results in selective degeneration of the striatum. This is caused by a mutation in the protein, huntingtin, however, the mechanisms responsible for neuronal degeneration remain unknown. Similar to the brains of HD patients, HD transgenic mice exhibit huntingtin protein aggregation and nuclear inclusions, selective degeneration of dopamine neurons in the striatum and dopamine receptor dysfunction. In this study, the gene expression patterns of HD transgenic mice were analyzed. Four groups, pre-symptomatic HD mice (6 weeks old), WT control (6 weeks), post symptomatic HD (16 weeks), and WT control (16 weeks), were hybridized and analyzed using the GLYCOv2 array. Each group was hybridized in triplicate.
2011-03-02 | E-GEOD-27588 | biostudies-arrayexpress
Project description:Aberrant display of the truncated core1 O-glycan T-antigen is a common feature of human cancer cells that correlates with metastasis. Here we show that T-antigen in Drosophila melanogaster macrophages is involved in their developmentally programmed tissue invasion. Higher macrophage T-antigen levels require an atypical major facilitator superfamily (MFS) member that we named Minerva which enables macrophage dissemination and invasion. We characterize for the first time the T and Tn glycoform O-glycoproteome of the Drosophila melanogaster embryo, and determine that Minerva increases the presence of T-antigen on protein pathways previously linked to cancer, most strongly on the protein sulfhydryl oxidase Qsox1 which we show is required for macrophage invasion. Minerva’s vertebrate ortholog, MFSD1, rescues the minerva mutant’s migration and T-antigen glycosylation defects. We thus identify a key conserved regulator that orchestrates O-glycosylation on a protein subset to activate a program governing migration steps important for both development and cancer metastasis
2019-04-01 | PXD011045 | Pride
Project description:This laboratory focuses on the molecular mechanisms of neuropsychiatric and neurodegenerative disorders Our goal is to elucidate mechanisms by which regulated expression of proteoglycans and glycosylation-related genes contribute to neurodegenerative diseases involving the striatum. A number of studies have demonstrated that neural proteoglycans are involved structural organization of the striatum and formation of dopaminergic connections to and from the striatum. Several proteoglycans are also associated with neuronal regeneration and some have been shown to be components of filamentous inclusions found in neurodegenerative disorders. In addition, the localization and proper function of dopamine receptors, which are predominantly expressed in the striatum, are governed by N-linked glycosylation events. Huntingtonís Disease (HD), a progressive neurodegenerative disorder, results in selective degeneration of the striatum. This is caused by a mutation in the protein, huntingtin, however, the mechanisms responsible for neuronal degeneration remain unknown. Similar to the brains of HD patients, HD transgenic mice exhibit huntingtin protein aggregation and nuclear inclusions, selective degeneration of dopamine neurons in the striatum and dopamine receptor dysfunction.
2011-03-02 | GSE27588 | GEO
Project description:Much of the N-glycosylation machinery was identified decades ago, but the regulatory mechanisms influencing normal and disease states are only beginning to be discovered. Recent studies highlight a role for key metabolites and metabolic enzymes in this process, revising the view of the relationship between different metabolic pathways. Using a multi-omic approach in a zebrafish, we discovered a mechanism where O-GlcNAcylation directly influences the expression and abundance of two enzymes essential for the earliest steps of N-linked glycosylation, the nus1-encoded NgBR and Dpagt1. Here we show that phosphomannomutase (pmm2) deficiency is associated with increased levels of UDP-GlcNAc and protein O-GlcNAcylation. Biochemical studies show that O-GlcNAc modification of the NgBR and Dpagt1 increases their abundance in pmm2m/m mutants. Modulating O-GlcNAc levels, NgBR abundance or Dpagt1 activity exacerbated cartilage phenotypes in pmm2 mutants, suggesting that O-GlcNAc mediated increases in the N-glycosylation machinery protects against more severe pathology. These findings highlight nucleotide-sugar donors as metabolic sensors that coordinate two different glycosylation pathways, demonstrating how their interplay is relevant to disease outcome in the most common congenital disorder of glycosylation.
2024-12-27 | GSE269074 | GEO