O-GlcNAcylation of E3 ubiquitin ligase SKP2 promotes hepatocellular carcinoma proliferation
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo Sapiens
SUBMITTER: 
Luyi Huang
PROVIDER: PXD048234 | iProX | Thu Jan 04 00:00:00 GMT 2024
REPOSITORIES: iProX
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Project description:Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the first rate-limiting enzyme in the hexosamine biosynthetic pathway (HBP), is a key factor controlling HBP flux. However, the molecular mechanism underlying the roles of GFAT1 in hepatocellular carcinoma (HCC) remain to be elucidated. Here, we found that GFAT1 was upregulated in HCC, and high GFAT1 level was correlated with poor patient prognosis. Our in vitro and in vivo studies demonstrated that GFAT1 facilitated hepatoma cell proliferation and invasion by enhancing HBP and O-GlcNAcylation through its enzymatic activity. Global profiling of O-GlcNAcylation identified vascular endothelial zinc finger protein 1 (VEZF1) as a substrate heavily O-GlcNAcylated in GFAT1-overexpressing hepatoma cells. Notably, O-GlcNAcylation at specific serine residues (Ser123 and Ser124) within VEZF1 attenuated its proteasomal degradation, thereby enhancing its protein stability and promoting tensin 1 (TNS1) transcription in HCC. In addition, we designed a bioactive VEZF1-derived peptide to competitively inhibit GFAT1-mediated O-GlcNAcylation of VEZF1. This intervention effectively reduced TNS1 expression and suppressed the progression of HCC in a mouse model. Together, these findings highlight the therapeutic potential of targeting the GFAT1-VEZF1-TNS1 signaling axis in HCC.
2025-08-26 | GSE278232 | GEO
Project description:Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the first rate-limiting enzyme in the hexosamine biosynthetic pathway (HBP), is a key factor controlling HBP flux. However, the molecular mechanism underlying the roles of GFAT1 in hepatocellular carcinoma (HCC) remain to be elucidated. Here, we found that GFAT1 was upregulated in HCC, and high GFAT1 level was correlated with poor patient prognosis. Our in vitro and in vivo studies demonstrated that GFAT1 facilitated hepatoma cell proliferation and invasion by enhancing HBP and O-GlcNAcylation through its enzymatic activity. Global profiling of O-GlcNAcylation identified vascular endothelial zinc finger protein 1 (VEZF1) as a substrate heavily O-GlcNAcylated in GFAT1-overexpressing hepatoma cells. Notably, O-GlcNAcylation at specific serine residues (Ser123 and Ser124) within VEZF1 attenuated its proteasomal degradation, thereby enhancing its protein stability and promoting tensin 1 (TNS1) transcription in HCC. In addition, we designed a bioactive VEZF1-derived peptide to competitively inhibit GFAT1-mediated O-GlcNAcylation of VEZF1. This intervention effectively reduced TNS1 expression and suppressed the progression of HCC in a mouse model. Together, these findings highlight the therapeutic potential of targeting the GFAT1-VEZF1-TNS1 signaling axis in HCC.
2025-08-26 | GSE278334 | GEO
Project description:The anaphase promoting complex/cyclosome (APC/C) is a ubiquitin ligase that controls progression through the eukaryotic cell cycle by targeting key substrates for degradation through the ubiquitin proteasome pathway. During G1, the APC/C works in concert with its co-activator Cdh1 to recognize and ubiquitinate specific substrates during this phase of the cell cycle. While many APC/CCdh1 substrates play a role cell cycle regulation, others are involved in distinct cellular processes, indicating that diverse biological pathways are subject to APC/C-mediated control. To identify novel pathways and substrates regulated by APC/CCdh1, we conducted an unbiased proteomic screen in G1-arrested RPE1 cells acutely treated with small molecule APC/C inhibitors. Combining these results with degron prediction analysis, we discovered a range of putative APC/C substrates. We validated IRS2, a key adaptor protein involved in signaling downstream of the insulin and IGF1 receptors, as a novel direct APC/CCdh1 target. We demonstrate that genetic deletion of IRS2 reduces the expression of proteins involved in cell division and functionally impairs the spindle assembly checkpoint. Together, these findings reveal a novel connection between the insulin/IGF1 signaling network and the cell cycle regulatory machinery.
2020-06-22 | PXD018329 | Pride
Project description:O-GlcNAc glycosylation is a prevalent protein post-translational modification (PTM) that occurs intracellularly. Previous investigations have demonstrated that O-GlcNAcylation crosstalks with phosphorylation and ubiquitination, but it is unclear whether it interplays with other PTMs. Here we studied its relationship with ADP-ribosylation, which involves decorating target proteins with the ADP-ribose moiety. We discovered that one ADP-ribosylation “eraser”- ADP-ribose glycohydrolase (PARG)- is O-GlcNAcylated at Ser26. O-GlcNAcylation of PARG is essential to maintain its nuclear localization and chromatin association. In hepatocellular carcinoma (HCC) cells, PARG O-GlcNAcylation enhances DNA damage-binding protein 1 (DDB1) poly(ADP-ribosyl)ation (PARylation) and attenuates its ubiquitination. DDB1 is thus stabilized and degrades its downstream targets, such as c-Myc. We further utilized mouse xenograft models and demonstrated that PARG-S26A promoted HCC. Our study thus revealed that PARG O-GlcNAcylation inhibits HCC, and we propose that O-GlcNAc glycosylation may crosstalk with many other PTMs.
2024-01-26 | PXD041119 | Pride
Project description:Introduction: The anaphase-promoting complex/cyclosome (APC/C) is a multi-subunit E3 ubiquitin ligase critically involved in cell cycle regulation. However, the pathological functions of its individual subunits, particularly in hepatocellular carcinoma (HCC), remain largely unexplored. Objectives: To systematically analyze the expression and prognosis of APC/C in pan-cancer, and also focus on studying the function and mechanism of APC7 in the progression of HCC.
2026-05-15 | GSE319107 | GEO
Project description:<p>Cell size and the cell cycle are intrinsically coupled and abnormal increases in cell size are associated with senescence and permanent cell cycle arrest. The mechanism by which overgrowth primes cells to withdraw from the cell cycle remains unknown. We investigate this here using CDK4/6 inhibitors that arrest cell cycle progression during G0/G1 and are used in the clinic to treat ER+/HER2- metastatic breast cancer. We demonstrate that CDK4/6 inhibition promotes cellular overgrowth during G0/G1, causing p38MAPK-p53-p21-dependent cell cycle withdrawal. We find that cell cycle withdrawal is triggered by two waves of p21 induction. First, overgrowth during a long-term G0/G1 arrest induces an osmotic stress response. This stress response produces the first wave of p21 induction. Second, when CDK4/6 inhibitors are removed, a fraction of cells escape long term G0/G1 arrest and enter S-phase where overgrowth-driven replication stress results in a second wave of p21 induction that causes cell cycle withdrawal from G2, or the subsequent G1. We propose a model whereby both waves of p21 induction contribute to promote permanent cell cycle arrest. This model could explain why cellular hypertrophy is associated with senescence and why CDK4/6 inhibitors have long-lasting effects in patients.</p>
2025-10-24 | MTBLS5868 | MetaboLights
Project description:Abnormal increases in cell size are associated with senescence and cell cycle exit. The mechanisms by which overgrowth primes cells to withdraw from the cell cycle remain unknown. We address this question using CDK4/6 inhibitors, which arrest cells in G0/G1 and are licensed to treat advanced HR+/HER2- breast cancer. We demonstrate that CDK4/6-inhibited cells overgrow during G0/G1, causing p38/p53/p21-dependent cell cycle withdrawal. Cell cycle withdrawal is triggered by biphasic p21 induction. The first p21 wave is caused by osmotic stress, leading to p38- and size-dependent accumulation of p21. CDK4/6 inhibitor washout results in some cells entering S-phase. Overgrown cells experience replication stress, resulting in a second p21 wave that promotes cell cycle withdrawal from G2 or the subsequent G1. We propose that the levels of p21 integrate signals from overgrowth-triggered stresses to determine cell fate. This model explains how hypertrophy can drive senescence and why CDK4/6 inhibitors have long-lasting effects in patients.
2025-10-24 | MTBLS8698 | MetaboLights
Project description:Barr2017 - Dynamics of p21 in hTert-RPE1
cells
This deteministic model reveals that a
bistable switch created by Cdt2, promotes irreversible S-phase
entry by keeping p21 levels low, prevents premature S-phase exit
upon DNA damage
This model is described in the article:
DNA damage during S-phase
mediates the proliferation-quiescence decision in the
subsequent G1 via p21 expression.
Barr AR, Cooper S, Heldt FS, Butera
F, Stoy H, Mansfeld J, Novák B, Bakal C.
Nat Commun 2017 Mar; 8: 14728
Abstract:
Following DNA damage caused by exogenous sources, such as
ionizing radiation, the tumour suppressor p53 mediates cell
cycle arrest via expression of the CDK inhibitor, p21. However,
the role of p21 in maintaining genomic stability in the absence
of exogenous DNA-damaging agents is unclear. Here, using live
single-cell measurements of p21 protein in proliferating
cultures, we show that naturally occurring DNA damage incurred
over S-phase causes p53-dependent accumulation of p21 during
mother G2- and daughter G1-phases. High p21 levels mediate G1
arrest via CDK inhibition, yet lower levels have no impact on
G1 progression, and the ubiquitin ligases CRL4Cdt2 and SCFSkp2
couple to degrade p21 prior to the G1/S transition.
Mathematical modelling reveals that a bistable switch, created
by CRL4Cdt2, promotes irreversible S-phase entry by keeping p21
levels low, preventing premature S-phase exit upon DNA damage.
Thus, we characterize how p21 regulates the
proliferation-quiescence decision to maintain genomic
stability.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000660.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
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neighbouring rights to this encoded model have been dedicated to
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2024-09-02 | BIOMD0000000660 | BioModels
Project description:Cell size and the cell cycle are intrinsically coupled and abnormal increases in cell size are associated with senescence and permanent cell cycle arrest. The mechanism by which overgrowth primes cells to withdraw from the cell cycle remains unknown. We investigate this here using CDK4/6 inhibitors that arrest cell cycle progression during G0/G1 and are used in the clinic to treat ER+/HER2- metastatic breast cancer. We demonstrate that CDK4/6 inhibition promotes cellular overgrowth during G0/G1, causing p38MAPK-p53-p21-dependent cell cycle withdrawal. We find that cell cycle withdrawal is triggered by two waves of p21 induction. First, overgrowth during a long-term G0/G1 arrest induces an osmotic stress response. This stress response produces the first wave of p21 induction. Second, when CDK4/6 inhibitors are removed, a fraction of cells escape long term G0/G1 arrest and enter S-phase where overgrowth-driven replication stress results in a second wave of p21 induction that causes cell cycle withdrawal from G2, or the subsequent G1. We propose a model whereby both waves of p21 induction contribute to promote permanent cell cycle arrest. This model could explain why cellular hypertrophy is associated with senescence and why CDK4/6 inhibitors have long-lasting effects in patients.
2023-11-27 | PXD036519 | Pride
Project description:The large majority of oxidative lesions occurring in the G1 phase of the cell cycle are repaired by base excision repair (BER) rather than mismatch repair (MMR) to avoid long resections that can lead to genomic instability and cell death. However, how cells choose BER over MMR is not yet understood. Here, we show that, during G1, D-type cyclins are recruited to sites of oxidative DNA damage in a PCNA- and p21-dependent manner. In turn, in a manner that is independent on CDK4/6 activity, D-type cyclins stabilize p21, which competes through its PCNA-interacting protein (PIP) box with MMR components for their binding to PCNA. This reduces MMR activity while allowing BER. At the G1/S transition, the AMBRA1-dependent degradation of D-type cyclins renders p21 susceptible to proteolysis via SKP2 and CDT2. These timely degradation events allow the proper binding of MMR proteins to PCNA enabling the repair of DNA replication errors. Thus, the expression of D-type cyclins limit MMR in G1, whereas their degradation is necessary for proper MMR function in S. Defects in these two regulatory mechanisms promote genome instability. The mass spectrometry raw files correspond to the affinity purifications of proximity labeled (turbo-ID) PCNA and CCND1 under various conditions.
2023-01-03 | MSV000091006 | MassIVE