Inhibition of O-GlcNAc transferase activates tumor-suppressor gene expression in tamoxifen-resistant breast cancer cells
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PROVIDER: PRJNA623391 | ENA |
REPOSITORIES: ENA
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Project description:In this study, we probed the importance of OGT activity for the survival of Tamoxifen-sensitive (TamS) and Tamoxifen-resistant (TamR) breast cancer cells. Tamoxifen is an antagonist of estrogen receptor (ERα), a transcription factor expressed in over half of all breast cancers, and the defining characteristic of the ERα-positive disease. ERα-positive breast cancers are successfully treated with Tamoxifen; however, a significant number of patients develops Tamoxifen-resistant disease. We show here that in vitro development of Tamoxifen-resistance results in acquired sensitivity to OGT small molecule inhibitor OSMI-1. Global transcriptome profiling revealed that TamS cells adapt to OSMI-1 treatment by undergoing significant chromatin compaction. In the TamR cells, however, OGT inhibition induces ERRFI1 tumor-suppressor gene expression. ERRFI1 is an endogenous inhibitor of ERBB-signaling, while activation of the ERBB-signaling is one of the best understood mechanism for Tamoxifen-resistance. We show that ERRFI1 is selectively downregulated in ERα-positive breast cancers and breast cancers driven by ERBB2, and provide data to support that this occurs through promoter methylation. Finally, we show that increased ERRFI1 expression is associated with extended survival in patients with ERα-positive tumors (p=9.2e-8). In summary, we show that Tamoxifen-resistance is associated with acquired sensitivity to OSMI-1, and propose that this is explained in part through an epigenetic activation of the tumor-suppressor ERRFI1 in response to OSMI-1 treatment.
2020-10-22 | GSE148186 | GEO
Project description:Single cell RNA sequencing, 5 week deletion of O-GlcNAc transferase (OGT) in hepatocytes
2023-11-08 | GSE223830 | GEO
Project description:In this study, we probed the importance of O-GlcNAc transferase (OGT) activity for the survival of tamoxifen-sensitive (TamS) and tamoxifen-resistant (TamR) breast cancer cells. Tamoxifen is an antagonist of estrogen receptor (ERα), a transcription factor expressed in over 50% of breast cancers. ERα-positive breast cancers are successfully treated with tamoxifen; however, a significant number of patients develop tamoxifen-resistant disease. We show that in vitro development of tamoxifen-resistance is associated with increased sensitivity to the OGT small molecule inhibitor OSMI-1. Global transcriptome profiling revealed that TamS cells adapt to OSMI-1 treatment by increasing the expression of histone genes. This is known to mediate chromatin compaction. In contrast, TamR cells respond to OGT inhibition by activating the unfolded protein response and by significantly increasing ERRFI1 expression. ERRFI1 is an endogenous inhibitor of ERBB-signaling, which is a known driver of tamoxifen-resistance. We show that ERRFI1 is selectively downregulated in ERα-positive breast cancers and breast cancers driven by ERBB2. This likely occurs via promoter methylation. Finally, we show that increased ERRFI1 expression is associated with extended survival in patients with ERα-positive tumors (p = 9.2e-8). In summary, we show that tamoxifen-resistance is associated with sensitivity to OSMI-1, and propose that this is explained in part through an epigenetic activation of the tumor-suppressor ERRFI1 in response to OSMI-1 treatment.
| S-EPMC7552408 | biostudies-literature
Project description:O-GlcNAcylation is the modification of serine and threonine residues with beta-N-acetylglucosamine (O-GlcNAc) on intracellular proteins. To investigate the role of protein O-GlcNAcylation on intestinal homeostasis, we generated intestinal epithelial cell (IEC)-specific O-GlcNAc transferase (OGT) knockout in mice. The KO mice developed spontanous intestinal inflammation. To determine the underlying molecular mechanisms, we performed RNA sequencing of ileum and colon epithelial cells of wildtype and IEC-OGT KO mice.
2017-06-27 | GSE100473 | GEO
Project description:Discriminating pathogenic bacteria from energy-harvesting commensals is key to host immunity. Using mutants defective in the enzymes of O-linked N-acetylglucosamine (O-GlcNAc) cycling, we examined the role of this nutrient-sensing pathway in the Caenorhabidits elegans innate immune response. Using whole genome transcriptional profiling, O-GlcNAc cycling mutants exhibited deregulation of unique stress- and immune-responsive genes as well as genes shared with the p38 MAPK/PMK-1 pathway. Moreover, genetic analysis showed that deletion of O-GlcNAc transferase (ogt-1) yielded animals hypersensitive to the human pathogen S. aureus but not to P. aeruginosa. Genetic interaction studies further revealed that nutrient-responsive OGT-1 acts through the conserved ß-catenin (BAR-1) pathway and in concert with p38 MAPK/PMK-1 to modulate the immune response to S. aureus. The participation of the nutrient sensor O-GlcNAc transferase in an immunity module conserved from C. elegans to humans reveals an unexplored nexus between nutrient availability and a pathogen-specific immune response. In C. elegans, three mutant strains(genotypes used: N2 (wild-type), ogt-1 (ok1474), oga-1 (ok1207), and pmk-1 (km25)) were treated with the human pathogen S. aureus (SA) or P. aeruginosa(PA) and OP50 (E. coli control) with three biological replications.
2015-05-01 | E-GEOD-53732 | biostudies-arrayexpress
Project description:Discriminating pathogenic bacteria from energy-harvesting commensals is key to host immunity. Using mutants defective in the enzymes of O-linked N-acetylglucosamine (O-GlcNAc) cycling, we examined the role of this nutrient-sensing pathway in the Caenorhabidits elegans innate immune response. Using whole genome transcriptional profiling, O-GlcNAc cycling mutants exhibited deregulation of unique stress- and immune-responsive genes as well as genes shared with the p38 MAPK/PMK-1 pathway. Moreover, genetic analysis showed that deletion of O-GlcNAc transferase (ogt-1) yielded animals hypersensitive to the human pathogen S. aureus but not to P. aeruginosa. Genetic interaction studies further revealed that nutrient-responsive OGT-1 acts through the conserved ß-catenin (BAR-1) pathway and in concert with p38 MAPK/PMK-1 to modulate the immune response to S. aureus. The participation of the nutrient sensor O-GlcNAc transferase in an immunity module conserved from C. elegans to humans reveals an unexplored nexus between nutrient availability and a pathogen-specific immune response.
2015-05-01 | GSE53732 | GEO
Project description:An X-chromosome exome sequencing analysis identified a mutation in O-GlcNAc transferase (OGT) (pL254F) in a family with X-linked intellectual disability (XLID). Affected patient lymohoblastoids exhibit decreased steady state OGT levels owing to an unstable protein compared to the unaffected, related male controls. Suprisingly, global O-GlcNAc levels remained remained unaltered. This prompted us to check the both protein and mRNA levels of the other cycling enzyme, O-GlcNAcase (OGA) which was also lowered. This implies that a compensation mechanism exists, however imperfect, owing to the disease state of the individuals. We performed glabal transcriptome analysis to assess any other changes in message between patients and controls. Our study highlights small differences in the global transcriptome of patient lymhoblastoids that have the L254F mutation in O-GlcNAc transferase when compared to familial controls using Illumina sequencing of total RNA
2016-02-25 | E-GEOD-74263 | biostudies-arrayexpress
Project description:We report that cellular O-GlcNAcylation levels decline along the course of megakaryocyte (MK) differentiation from human-derived hematopoietic stem and progenitor cells (HSPCs) and that inhibition of O-GlcNAc transferase (OGT), of which catalyzes O-GlcNAcylation, prolongedly decreases O-GlcNAcylation and induces megakaryopoiesis and thrombopoiesis. To gain the better insight into the potential mechanisms underlying platelet regulation by O-GlcNAcylation ,we compared the genome-wide transcription profiles of megakaryblastic MEG-01 cells with decreased O-GlcNAcylation (OGTi) and its control counterpart using RNA sequencing. Gene ontology and enrichment analysis of differentially expressed genes suggest that platelet formation might be regulated through the perturbation in cell adhesion molecules, i.e. integrin-a4 and b7, downstream of O-GlcNAc/c-Myc axis.
2020-08-06 | GSE150880 | GEO
Project description:Abstract: O-GlcNAc is an abundant post-translational modification found on nuclear and cytoplasmic proteins in all metazoans. This modification regulates a wide variety of cellular processes, and elevated O-GlcNAc levels have been implicated in cancer progression. A single essential enzyme, O-GlcNAc transferase (OGT), is responsible for all nucleocytoplasmic O-GlcNAcylation. Understanding how this enzyme chooses its substrates is critical for understanding, and potentially manipulating, its functions. Here we use protein microarray technology and proteome-wide glycosylation profiling to show that conserved aspartate residues in the tetratricopeptide repeat (TPR) lumen of OGT drive substrate selection. Changing these residues to alanines alters substrate selectivity and unexpectedly increases rates of protein glycosylation. Our findings support a model where sites of glycosylation for many OGT substrates are determined by TPR domain contacts to substrate side chains five to fifteen residues C-terminal to the glycosite. In addition to guiding design of inhibitors that target OGT's TPR domain, this information will inform efforts to engineer substrates to explore biological functions.
2019-07-24 | GSE132205 | GEO
Project description:Effect of O-GlcNAc Transferase (OGT) siRNA in trophoblastic BeWo cells
| PRJNA827804 | ENA