Glycosylation regulates the stability of c-MYC
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE44624 | GEO | 2013/05/30
SECONDARY ACCESSION(S): PRJNA190675
REPOSITORIES: GEO
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Project description:Tumorigenesis is characterised by changes in transcriptional regulation and the androgen receptor (AR) has been identified as a key driver in prostate cancer. In this study, we show that the hexosamine biosynthetic pathway (HBP) genes are overexpressed in clinical prostate cancer and androgen-regulated in cell-lines. HBP senses metabolic status of the cell and produces an essential substrate for O-GlcNAc transferase (OGT), which regulates target proteins via glycosylation. Using immunohistochemistry, we found that OGT is up-regulated in the protein level in prostate cancer (n=1987) and its expression correlates with high Gleason Score, pT and pN stages and biochemical recurrence (for all, p<0.0001). Both a small molecule inhibitor and siRNAs targeting OGT decreased prostate cancer cell growth. Microarray profiling revealed that the principal effects of the OGT inhibitor in prostate cancer cells are on cell cycle progression and DNA replication. We identified MYC as a candidate upstream regulator of these genes and found that OGT inhibitor caused a dose-dependent loss of c-MYC protein but not mRNA in cell lines. Finally, we observed a statistically significant co-expression between c-MYC and OGT in human prostate cancer samples (n=1306, p=0.0012). Total RNA was extracted and experiment has three biological replicates for each condition, conditions are: 12 hours ST045849, 24 hours ST045849, 12 hours vehicle, 24 hours vehicle, 12 hours siOGT, 24 hours siOGT, 12 hours scrambled, 24 hours scrambled
2013-05-30 | E-GEOD-44624 | biostudies-arrayexpress
Project description:To better understand the biochemical changes associated with castrate resistant prostate cancer (CRPC), we developed a pathway-based integrated analytical method to examine prostate cancer (PCa) gene expression and metabolomic datasets and found distinct alterations in the Hexosamine Biosynthetic Pathway (HBP) between androgen dependent (AD) PCa and CRPC, with elevated expression of HBP genes in primary PCa associated with poor clinical outcome. Expression of the HBP enzyme glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) was regulated by androgens and elevated in AD PCa while relatively diminished in CRPC.Genetic loss of function experiments for GNPNAT1 in CRPC-like cells led to increased aggressiveness, while GNPNAT1 knockdown decreased proliferation in AD PCa cells. Each scenario was accompanied by specific bio-energetic and molecular alterations. Strikingly, addition of HBP metabolite UDP-N-acetylglucosamine significantly enhanced efficacy of the anti-androgen enzalutamide in CRPC cells by repressing NF-Y driven cell cycle regulators. Our study demonstrates the therapeutic value of targeting altered metabolic pathways in lethal PCa.
2016-09-20 | GSE50661 | GEO
Project description:O-GlcNAc transferase (OGT) is overexpressed in aggressive prostate cancer. Here, we employed ChIP-seq to map chromatin-bound O-GlcNAc loci in prostate cancer cells and discovered that these overlap with sites of active transcription and MYC binding. Using RNA-seq, we show that inhibition of OGT promotes MYC-dependent transcriptional repression of mRNAs involved in G1-S transition. O-GlcNAc ChIP-seq regions are highly enriched to transcription start sites and identify the ‘GFY’-motif. Proteins binding to this motif have not been established and we use synthetic oligonucleotides as a bait to enrich protein complexes associated with this sequence. By comparing the unbiased proteomic data from oligonucleotide enrichment with proteomic data from O-GlcNAc and MYC ChIP-mass spectrometry, we identified host cell factor 1 (HCF-1) as an interaction partner of MYC. Inhibition of OGT disrupted the interaction between MYC and HCF-1, and compromised MYC’s ability to promote proliferation of prostate cancer cells in the absence of androgens. Reverse phase protein arrays identified a set of proteins involved in mitosis that are dependent on MYC and OGT activity for expression. In conclusion, we show that OGT activity regulates MYC-driven proliferation by coordinating transcription and translation of cell cycle genes.
2019-05-21 | GSE112667 | GEO
Project description:O-GlcNAc transferase (OGT) is overexpressed in aggressive prostate cancer. Here, we employed ChIP-seq to map chromatin-bound O-GlcNAc loci in prostate cancer cells and discovered that these overlap with sites of active transcription and MYC binding. Using RNA-seq, we show that inhibition of OGT promotes MYC-dependent transcriptional repression of mRNAs involved in G1-S transition. O-GlcNAc ChIP-seq regions are highly enriched to transcription start sites and identify the ‘GFY’-motif. Proteins binding to this motif have not been established and we use synthetic oligonucleotides as a bait to enrich protein complexes associated with this sequence. By comparing the unbiased proteomic data from oligonucleotide enrichment with proteomic data from O-GlcNAc and MYC ChIP-mass spectrometry, we identified host cell factor 1 (HCF-1) as an interaction partner of MYC. Inhibition of OGT disrupted the interaction between MYC and HCF-1, and compromised MYC’s ability to promote proliferation of prostate cancer cells in the absence of androgens. Reverse phase protein arrays identified a set of proteins involved in mitosis that are dependent on MYC and OGT activity for expression. In conclusion, we show that OGT activity regulates MYC-driven proliferation by coordinating transcription and translation of cell cycle genes.
2019-05-21 | GSE121472 | GEO
Project description:The development and progression of castrate resistant prostate cancer (CRPC), a lethal disease, is thought to be driven by multiple events. A hallmark of CRPC is the ability to evade the cytotoxic effects of anti-androgen therapy. Importantly, persistent androgen receptor (AR) signalling is thought to play a principal role in maintaining CRPC. The precise molecular alterations driving this condition, however, are not clearly understood. Our previous studies identified specific metabolic alterations associated with localized prostate cancer (PCa) and CRPC, implicating metabolic re-programming in disease progression. Building on these findings, using a novel network-based integromics approach, here we show distinct alterations in the Hexosamine Biosynthetic Pathway (HBP) to be critical for sustaining the castrate resistant state. We found expression of the HBP enzyme glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) was regulated by androgens and elevated in androgen dependent (AD) PCa while relatively diminished in CRPC possessing either full length AR (AR-FL) or the spliced V7 variant (AR-V7). Genetic loss of function experiments for GNPNAT1 in CRPC-like cells led to increased proliferation and aggressiveness, both, in vitro and in vivo. This was mediated by specific cell cycle genes regulated by the PI3K-AKT pathway activating either AR in cells with AR-FL or SP1-ChREBP (carbohydrate response element binding protein) in cells containing AR-V7. Strikingly, addition of HBP metabolite UDP-N-acetylglucosamine (UDP) to CRPC-like cells reduced the expression of cell cycle genes and attenuated tumor cell proliferation, both in vitro and in vivo. Furthermore, addition of UDP sensitized CRPC-like cells, inclusive of those possessing AR-V7, to enzalutamide, demonstrating the therapeutic value of targeting altered metabolic pathways in lethal PCa. We anticipate that our findings will motivate the development of novel metabolic therapeutic strategies that complement existing treatments for men with lethal prostate cancer We used microarray analysis to determine key molecular alterations associated with inhibition of HBP pathway in CRPC by knocking down GNPNAT1 transcript level using lentiviral particle bearing shRNA in 22Rv1 and LNCaP-ABL cells GNPNAT1 expression was knockdown in two independent prostate cancer cells, 22Rv1 and LNCaP-ABL
2015-04-03 | E-GEOD-67537 | biostudies-arrayexpress
Project description:Metabolic reprogramming has emerged as one of the key hallmarks of cancer cells. Various metabolic pathways are dysregulated in cancers including hexosamine biosynthesis pathway (HBP). Protein O-GlcNAcylation catalyzed by O-GlcNAc transferase (OGT), the effector of HBP is found to be upregulated in most cancers. Post-translational O-GlcNAcylation of various signaling and transcriptional regulators could promote cancer cell maintenance and progression through protein stability and gene expression regulation. Indeed, among majority of O-GlcNAcylated proteins are gene specific transcription factors and chromatin regulators. Therefore, investigating the role of OGT in particular types of cancers is crucial. Here, we have investigated the role of OGT in glioblastoma. OGT knockdown and chemical inhibition led to reduced glioblastoma cell proliferation and downregulation of many genes known to play key roles in glioblastoma cell proliferation, migration and invasion.We knocked down OGT and OGA enzyme expression by shRNAs followed by RNA sequencing was carried.
2023-10-23 | GSE234473 | GEO
Project description:Prostate cancer is the commonest male cancer in Europe and the USA. The androgen receptor is a key transcription factor contributing to the development of all stages of the disease. In addition, other transcription factors have been associated with poor prognosis in prostate cancer, amongst which c-Myc is a well-established oncogene in many other cancers. We have previously reported that a role for the androgen receptor in prostate cancer is to promote glycolysis and anabolic metabolism. Many of these metabolic pathways are also c-Myc-regulated in other cancers. In this study we report that de novo purine biosynthesis is a c-Myc-dependent pathway in prostate cancer cells as determined by commensurate changes in the levels of enzymes in the pathway in response to siRNA knockdown of c-Myc and inducible overexpression of c-Myc. In addition c-Myc is recruited to the promoters of genes in the pathway as determined by chromatin immunoprecipitation. Using immunohistochemistry and real-time transcript detection we show that two enzymes (PAICS and IMPDH2) within the pathway are overexpressed in prostate cancers. An inhibitor of IMPDH2 reduces cell proliferation and significantly reduces the levels of guanosine triphosphate within treated cells. This imposes nucleolar stress on cells as determined by significant reductions in the levels of guanine nucleotide binding protein-like 3 (GNL3). In addition the levels of c-Myc, p53 and the androgen receptor are affected and the expression of tumour suppressive microRNA-34b is increased. Combining the IMPDH2 inhibitor with anti-androgens results in a combinatorial inhibition of cell proliferation. In conclusion we propose using enzymes within the de novo purine biosynthesis as cancer biomarkers and applying drugs to alter the flux through this pathway may represent an effective means of stratifying patients for therapy and sensitising some to AR-targeted therapies. Total RNA of three biological replicates for each condition was extracted using the RNeasy kit (Qiagen), conditions are: 5 h vehicle, 5 h Doxycycline, 12 h vehicle, 12 h Doxycyline
2016-03-17 | E-GEOD-51384 | biostudies-arrayexpress
Project description:O-GlcNAc transferase (OGT) is a nutrient-sensitive glycosyltransferase that is overexpressed in prostate cancer, the most common cancer in males. We recently developed specific and potent inhibitor targeting this enzyme, and here we report a synthetic lethality screen using this compound. Our screen identified pan-cyclin-dependent kinase (CDK) inhibitor AT7519 as lethal in combination with OGT inhibition. Follow-up chemical and genetic approaches identified CDK9 as the major target for synthetic lethality with OGT inhibition in prostate cancer cells. OGT expression is regulated through retention of the fourth intron in the gene and CDK9 inhibition blunted this regulatory mechanism. CDK9 phosphorylates carboxy-terminal domain (CTD) of RNA Polymerase II (RNA Pol II) to promote transcription elongation. We showed that OGT inhibition augments effects of CDK9 inhibitors on CTD phosphorylation and general transcription. Finally, the combined inhibition of both OGT and CDK9 blocked growth of organoids derived from metastatic prostate cancer patients but had minimal effects on normal prostate spheroids. We report a novel synthetic lethal interaction between inhibitors of OGT and CDK9 that specifically kills prostate cancer cells but not normal cells. Our study highlights the potential of combining OGT inhibitors with other treatments to exploit cancer specific vulnerabilities.
2020-08-18 | GSE116778 | GEO
Project description:Prostate cancer is the commonest male cancer in Europe and the USA. The androgen receptor is a key transcription factor contributing to the development of all stages of the disease. In addition, other transcription factors have been associated with poor prognosis in prostate cancer, amongst which c-Myc is a well-established oncogene in many other cancers. We have previously reported that a role for the androgen receptor in prostate cancer is to promote glycolysis and anabolic metabolism. Many of these metabolic pathways are also c-Myc-regulated in other cancers. In this study we report that de novo purine biosynthesis is a c-Myc-dependent pathway in prostate cancer cells as determined by commensurate changes in the levels of enzymes in the pathway in response to siRNA knockdown of c-Myc and inducible overexpression of c-Myc. In addition c-Myc is recruited to the promoters of genes in the pathway as determined by chromatin immunoprecipitation. Using immunohistochemistry and real-time transcript detection we show that two enzymes (PAICS and IMPDH2) within the pathway are overexpressed in prostate cancers. An inhibitor of IMPDH2 reduces cell proliferation and significantly reduces the levels of guanosine triphosphate within treated cells. This imposes nucleolar stress on cells as determined by significant reductions in the levels of guanine nucleotide binding protein-like 3 (GNL3). In addition the levels of c-Myc, p53 and the androgen receptor are affected and the expression of tumour suppressive microRNA-34b is increased. Combining the IMPDH2 inhibitor with anti-androgens results in a combinatorial inhibition of cell proliferation. In conclusion we propose using enzymes within the de novo purine biosynthesis as cancer biomarkers and applying drugs to alter the flux through this pathway may represent an effective means of stratifying patients for therapy and sensitising some to AR-targeted therapies.
2016-03-17 | GSE51384 | GEO
Project description:The development and progression of castrate resistant prostate cancer (CRPC), a lethal disease, is thought to be driven by multiple events. A hallmark of CRPC is the ability to evade the cytotoxic effects of anti-androgen therapy. Importantly, persistent androgen receptor (AR) signalling is thought to play a principal role in maintaining CRPC. The precise molecular alterations driving this condition, however, are not clearly understood. Our previous studies identified specific metabolic alterations associated with localized prostate cancer (PCa) and CRPC, implicating metabolic re-programming in disease progression. Building on these findings, using a novel network-based integromics approach, here we show distinct alterations in the Hexosamine Biosynthetic Pathway (HBP) to be critical for sustaining the castrate resistant state. We found expression of the HBP enzyme glucosamine-phosphate N-acetyltransferase 1 (GNPNAT1) was regulated by androgens and elevated in androgen dependent (AD) PCa while relatively diminished in CRPC possessing either full length AR (AR-FL) or the spliced V7 variant (AR-V7). Genetic loss of function experiments for GNPNAT1 in CRPC-like cells led to increased proliferation and aggressiveness, both, in vitro and in vivo. This was mediated by specific cell cycle genes regulated by the PI3K-AKT pathway activating either AR in cells with AR-FL or SP1-ChREBP (carbohydrate response element binding protein) in cells containing AR-V7. Strikingly, addition of HBP metabolite UDP-N-acetylglucosamine (UDP) to CRPC-like cells reduced the expression of cell cycle genes and attenuated tumor cell proliferation, both in vitro and in vivo. Furthermore, addition of UDP sensitized CRPC-like cells, inclusive of those possessing AR-V7, to enzalutamide, demonstrating the therapeutic value of targeting altered metabolic pathways in lethal PCa. We anticipate that our findings will motivate the development of novel metabolic therapeutic strategies that complement existing treatments for men with lethal prostate cancer We used microarray analysis to determine key molecular alterations associated with inhibition of HBP pathway in CRPC by knocking down GNPNAT1 transcript level using lentiviral particle bearing shRNA in 22Rv1 and LNCaP-ABL cells
2015-04-03 | GSE67537 | GEO