Project description:This study provides a genome-wide map of changes in degradative ubiquitination in response to proteasome inhibition in the multiple myeloma cell line MM.1S. Following proteasome inhibition with lactacystin, CUT and RUN assays were carried out to determine the genomic locations of ubiquitin in multiple myeloma cells stably expressing a flagged version of ubiquitin (MM.1S-3XFlag Ubiquitin cells). In addition, we report the DNA binding locations of the transcription factor c-MYC in basal conditions in MM.1S parental cells.
Project description:Relapsed/refractory multiple myeloma (r/r MM) is a disease with often poor prognosis. Hyperactive SUMO signaling is involved in both cancer pathogenesis and cancer progression. A state of increased SUMOylation has been associated with aggressive cancer biology. Here, we found that r/r MM is characterized by a SUMO-high state, and high expression of SUMO E1 ligase (SAE1/UBA2) was associated with poor overall survival. Induced resistance to the second generation proteasome inhibitor (PI) carfilzomib (CFZ) enhanced SUMO pathway activity. Accordingly, CFZ-pretreated patients showed enhanced SUMO pathway activity in the MM compartment. Treatment of MM cell lines with subasumstat, a novel small-molecule SUMO E1 activating enzyme inhibitor, showed synergistic treatment efficacy with CFZ in both PI-sensitive and PI-resistant MM cell lines irrespective of the TP53 state. Combination therapy was effective in two murine MM xenograft models, where in vivo growth was significantly inhibited, and in patient-derived primary MM cells in vitro. Mechanistically, combined subasumstat and CFZ treatment enhanced DNA stress and apoptosis. In summary, our findings reveal activated SUMOylation as a therapeutic target in MM and point to combined SUMO/proteasome inhibition as a novel potent strategy for the treatment of patients with MM.
Project description:NguyenLK2011 - Ubiquitination dynamics in
Ring1B-Bmi1 system
This theoretical model investigates the
dynamics of Ring1B/Bmi1 ubiquitination to identify bistable
switch-like and oscillatory behaviour in the
system. Michaelis-Menten (MM) equations are used to formulate
the model. However, the authors show that the dynamics persist even
for Mass-Action kinetics. This SBML file is the MM version of the
model.
This model is described in the article:
Switches,
excitable responses and oscillations in the Ring1B/Bmi1
ubiquitination system.
Nguyen LK, Muñoz-García J,
Maccario H, Ciechanover A, Kolch W, Kholodenko BN.
PLoS Comput. Biol. 2011 Dec; 7(12):
e1002317
Abstract:
In an active, self-ubiquitinated state, the Ring1B ligase
monoubiquitinates histone H2A playing a critical role in
Polycomb-mediated gene silencing. Following ubiquitination by
external ligases, Ring1B is targeted for proteosomal
degradation. Using biochemical data and computational modeling,
we show that the Ring1B ligase can exhibit abrupt switches,
overshoot transitions and self-perpetuating oscillations
between its distinct ubiquitination and activity states. These
different Ring1B states display canonical or multiply branched,
atypical polyubiquitin chains and involve association with the
Polycomb-group protein Bmi1. Bistable switches and oscillations
may lead to all-or-none histone H2A monoubiquitination rates
and result in discrete periods of gene (in)activity. Switches,
overshoots and oscillations in Ring1B catalytic activity and
proteosomal degradation are controlled by the abundances of
Bmi1 and Ring1B, and the activities and abundances of external
ligases and deubiquitinases, such as E6-AP and USP7.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000622.
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quantitative kinetic models.
To the extent possible under law, all copyright and related or
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Project description:Resistance to proteasome inhibitors has prompted interest in blocking upstream components of the ubiquitin-proteasome pathway for the treatment of multiple myeloma (MM). We therefore evaluated the activity of TAK-243, a novel and specific inhibitor of E1 ubiquitin activating enzyme (UAE) activity, in the MM cell line MM1.S. Treatment of MM1.S with 25 nM TAK-243 for 24 hr caused extensive changes in gene expression, highly uniform between triplicates.
Project description:Bortezomib (BTZ), Carfilzomib (CFZ) and Ixazomib (IXA) are proteasome inhibitors (PI) approved for Multiple Myeloma (MM) treatment. By design, they all target the rate-limiting proteasome beta 5 (B5) subunit. CFZ treatment increases the survival of patients with relapsed/refractory MM compared to BTZ but is associated with heart failure not commonly observed for BTZ. The molecular basis for CFZ-induced cardiotoxicity is poorly understood. We time to investigate the transcriptomic effects of acute proteasome inhibition in the murine heart.
Project description:The goal was to determine the gene expression differences between CB-5083 and Bortezomib treated multiple myeloma cell lines Inhibition of the AAA ATPase, p97, was recently shown to be a novel method for targeting the ubiquitin proteasome system (UPS) and CB-5083, a first in class inhibitor of p97, has demonstrated broad antitumor activity in a range of both hematological and solid tumor models. Here, we show that CB-5083 has robust activity against multiple myeloma (MM) cell lines and a number of in vivo MM models. Treatment with CB-5083 is associated with accumulation of ubiquitinated proteins, induction of the unfolded protein response (UPR) and apoptosis. CB-5083 decreases viability in MM cell lines and patient derived MM cells, including those with background proteasome inhibitor (PI) resistance. CB-5083 has a unique mechanism of action that combines well with PIs which is likely owing to the p97-dependent retro-translocation of the transcription factor, Nrf1, which transcribes proteasome subunit genes following exposure to a PI. In vivo studies using clinically relevant MM models demonstrate that single-agent CB-5083 inhibits tumor growth and combines well with MM standard of care agents. Our preclinical data demonstrate the efficacy of CB-5083 in several MM disease models and provide the rationale for clinical evaluation as monotherapy and in combination in MM.
Project description:SIRT3 deacetylase is a critical mitochondrial regulator for mitochondrial metabolism reprogramming and ROS production, and is involved in the regulation of chemoresistance in AML. SIRT3 is a SUMOylated protein, with de-SUMOylation by SENP1, resulted in enhancement of its deacetylase activity. However, the molecular mechanism of de-SUMOylation mediated SIRT3 activation, which may lead to reinforced AML chemoresistance, remains poorly understood. In the current study, we demonstrated that SIRT3 SUMOylation was attenuated by cytarabine, and de-SUMOylation prevented SIRT3 from proteasome degradation. SIRT3 de-SUMOylation was capable of reprogramming mitochondrial biogenesis, and subsequently inhibited mitochondrial ROS production. Furthermore, RNA-seq revealed that expression of a collection of genes was altered by SIRT3 de-SUMOylation, among which the transcription factor HES1, a downstream substrates of Notch1 signaling pathway, was significantly downregulated by SIRT3K288R, the de-SUMOylated and constitutively active mutant of SIRT3. HES1-dependent FAO was inhibited by SIRT3 de-SUMOylation. Moreover, cytarabine synergized with the SENP1 inhibitor momodrin-Ic to eradicate AML blasts in vitro and in xenografts mice models. In summary, the current study revealed a novel role of SIRT3 SUMOylation in regulating chemoresistance in AML via HES1-dependent FAO, which may provide a rationale for SIRT3 SUMOylation-targeted intervention to improve the chemotherapies in AML.
Project description:In addition to the glucocorticoids, the glucocorticoid receptor (GR) is regulated by post-translational modifications, including SUMOylation. We have analyzed how SUMOylation influences the activity of endogenous GR target genes and the receptor chromatin binding by using isogenic HEK293 cells expressing wild-type GR (wtGR) or SUMOylation-defective GR (GR3KR). Gene expression profiling revealed that both dexamethasone up- and down-regulated genes are affected by the GR sumoylation and that the affected genes are significantly associated with pathways of cellular proliferation and survival. The GR3KR-expressing cells proliferated more rapidly and their anti-proliferative response to dexamethasone was less pronounced than in the wtGR-expressing cells. ChIP-seq analyses indicated that the SUMOylation modulates the chromatin occupancy of GR on several loci associated with cellular growth in a fashion which parallels with their differential dexamethasone-regulated expression between the two cell lines. Moreover, genome-wide SUMO-2/3 marks, which were generally associated with active chromatin, showed markedly higher overlap with the wtGR cistrome than with the GR3KR cistrome. In sum, our results indicate that the SUMOylation does not simply repress the GR activity, but regulates the activity of the receptor in a target locus selective fashion, playing an important role in controlling the GR activity on genes influencing cell growth. Examination of GR and SUMO-2/3 binding from isogenic HEK293 cell lines stably expressing either wtGR or GR3KR, in biological duplicates, using Illumina HiSeq 2000. GR binding from control HEK293 (FRT) cell line and input sample from FRT were used as controls for GR. Sequenced IgG sample from FRT cell line was used as control for SUMO-2/3
Project description:Androgen receptor (AR) plays an important regulatory role during prostate cancer development. ARM-bM-^@M-^Ys transcriptional activity is regulated by androgenic ligands, but also by post-translational modifications. To study the role of the AR SUMOylation in genuine chromatin environment, we compared androgen-regulated gene expression and AR chromatin occupancy in PC-3 prostate cancer and HEK293 cell lines stably expressing wild-type (wt) or SUMOylation site-mutated AR (AR-K386R,K520R). Our genome-wide gene expression analyses reveal that the SUMOylation modulates the AR function in a target gene and pathway selective manner. The transcripts that are differentially regulated by androgen and SUMOylation are linked to cellular movement, cell death, cellular proliferation, cellular development and cell cycle. In line with these data, SUMOylation mutant AR cells proliferate faster and are more sensitive to apoptosis. Moreover, ChIP-seq analyses show that the SUMOylation modulates the chromatin occupancy of AR on many loci in a fashion that parallels with their differential androgen-regulated expression. De novo motif analyses show that other transcription factor-binding motifs are differentially enriched at the wtAR- and the AR-K386R,K520R-preferred genomic binding positions. Taken together, our data indicate that SUMOylation does not simply repress the AR activity, but it regulates ARM-bM-^@M-^Ys interaction with the chromatin and the receptorM-bM-^@M-^Ys target gene selection. Androgen receptor (AR) genomic binding was studied in wild-type AR (wtAR) or SUMOylation-deficient AR (AR-K2R) stably expressing cells HEK293 cells, in biological dublicates. Cells were treated 40 min either with 10 nM R1881 or EtOH (vehicle) and input was used as control (FRT_input GSM1176703).
Project description:Androgen receptor (AR) plays an important regulatory role during prostate cancer development. ARM-bM-^@M-^Ys transcriptional activity is regulated by androgenic ligands, but also by post-translational modifications. To study the role of the AR SUMOylation in genuine chromatin environment, we compared androgen-regulated gene expression and AR chromatin occupancy in PC-3 prostate cancer and HEK293 cell lines stably expressing wild-type (wt) or SUMOylation site-mutated AR (AR-K386R,K520R). Our genome-wide gene expression analyses reveal that the SUMOylation modulates the AR function in a target gene and pathway selective manner. The transcripts that are differentially regulated by androgen and SUMOylation are linked to cellular movement, cell death, cellular proliferation, cellular development and cell cycle. In line with these data, SUMOylation mutant AR cells proliferate faster and are more sensitive to apoptosis. Moreover, ChIP-seq analyses show that the SUMOylation modulates the chromatin occupancy of AR on many loci in a fashion that parallels with their differential androgen-regulated expression. De novo motif analyses show that other transcription factor-binding motifs are differentially enriched at the wtAR- and the AR-K386R,K520R-preferred genomic binding positions. Taken together, our data indicate that SUMOylation does not simply repress the AR activity, but it regulates ARM-bM-^@M-^Ys interaction with the chromatin and the receptorM-bM-^@M-^Ys target gene selection. Androgen receptor (AR) genomic binding was studied in wild-type AR (wtAR) or SUMOylation-deficient AR (AR-K2R) stably expressing cells PC-3 cells, in biological dublicates. Cells were treated 1h either with 10 nM R1881 or vehicle and inputs were used as controls.