Substrate Identification Using a Chemical Genetics Approach Reveals a Role for PARP-7-Mediated MARylation in Controlling Microtubule Stability in Ovarian Cancer Cells
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion Lumos
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: 
W Lee Kraus
PROVIDER: MSV000086611 | MassIVE | Thu Dec 17 07:28:00 GMT 2020
REPOSITORIES: MassIVE
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Project description:ADP-ribosylation (ADPRylation) is a regulatory posttranslational modification of proteins that results in the covalent attachment of ADP-ribose (ADPR) moieties on target proteins. PARP-7 (TiPARP) is a monoADPR transferase whose proteins substrates and biological activities are poorly understood. Here, we describe a chemical genetics approach that has allowed us to identify substrates of PARP-7 and explore their biological functions. We observed reduced levels of PARP7 mRNA in ovarian cancer patient samples versus normal tissue, but found nonetheless that PARP-7 is required for a number of cancer-related biological endpoints in ovarian cancer cells, including growth, migration, and invasion. Global gene expression and gene ontology analyses in ovarian cancer cells subjected to siRNA-mediated knockdown of PARP7 revealed an enrichment of genes encoding proteins with roles in cell-cell adhesion, cell cycle arrest, apoptosis, and gene regulation. To identify the ADPRylated substrates that underlie PARP-7-mediated ovarian cancer cell phenotypes, we developed an NAD+ analog-sensitive approach for PARP-7 comprising a PARP-7 NAD+ binding pocket mutant (S563G) paired with the NAD+ analog 8-Bu(3-yne)T-NAD+. When coupled with mass spectrometry, this approach allowed us to identify the PARP-7 ADP-ribosylated proteome in ovarian cancer cells, including components of the cell-cell adhesion and cytoskeleton organization machinery. Specifically, we found that PARP-7 monoADPRylates α-tubulin to promote microtubule instability, which may play a key role in the regulating ovarian cancer cell growth and motility. Collectively, our results point to an extensive PARP-7 ADP-ribosylated proteome with important roles in cancer-related cellular phenotypes.
2021-02-04 | GSE153395 | GEO
Project description:PARP7 (TiPARP), a mono (ADP-ribosyl) transferase (MART) was found to target α-tubulin proteins in ovarian cancer cells, enhancing their growth and migration. RBN-2397 is a potent inhibitor that selectively acts on PARP7. Here, we show that RBN-2397 treatment leads to the stabilization of microtubules in ovarian cancer cells, namely α-tubulin, mimicking what was previously observed with PARP7 knockdown. When treated with RBN-2397, we observe a decrease in growth and migration of ovarian cancer cells and, interestingly, the effect is intensified upon adding the microtubule stabilizing chemotherapeutic agent, paclitaxel. Mutating the site of α-tubulin MARylation by PARP7 similarly results in α-tubulin stabilization and decreased cell migration in the presence of paclitaxel when the tubulin network is further stabilized. In sum, we demonstrate that PARP7 inhibition decreases α-tubulin MARylation resulting in its stabilization, and ultimately leading to decreased ovarian cancer cell proliferation and migration. Finally, we show that combining PARP7 inhibitor and paclitaxel results in a more robust inhibition of aggressive ovarian cancer phenotypes. Collectively, this study highlights the potential of targeting PARP7 in combination with established chemotherapeutic agents to enhance treatment efficacy for ovarian cancer.
2024-10-01 | GSE268985 | GEO
Project description:The PARP family of proteins comprises 17 members, about two thirds of which are active mono- or poly(ADP-ribosyl)transferase enzymes that transfer the ADP-ribose moiety of NAD+ onto target proteins. In many cases, ADP-ribosylation, which plays critical roles in human diseases (e.g., cancer, heart disease, and neuropathies) is associated with abrogation of the molecular functions of the target. Discerning ADP-ribosylation events mediated by a specific PARP is challenging, since all PARPs use the same substrate (i.e., NAD+) and the available inhibitors lack the specificity needed to make such conclusions. In order to identify the direct and specific targets of individual PARP family members, we have developed a chemical and genetic approach known as analog sensitivity, in which alteration of a single conserved amino acid in the active site of the PARP protein creates a pocket that allows use of an unnatural NAD+ analog containing a steric moiety. We have functionalized the steric moiety with alkyne for use in click chemistry reactions. This approach, which is transferable to other PARP family members, creates substrate specificity where none previously existed, allowing PARP-specific post-translational modification followed by target visualization, or isolation of ADP-ribosylated targets using click chemistry techniques. We have used this technology in conjunction with mass spectrometry to identify hundreds of targets both unique to, as well as shared among, the nuclear PARP proteins, PARP-1, PARP-2, and PARP-3. We have also determined the genome-wide distribution of PARP-1-specific ADP-ribosylation by coupling this analog-sensitive PARP approach with chromatin cross-linking in method that we call “Click-ChIP-seq”. We observed that PARP-1-specific ADP-ribosylation is enriched at transcriptionally active promoters in proximity to sites of PARP-1 enrichment. In addition, we observed that NELF, an important regulator of RNA Polymerase II (Pol II) pausing, is not only a target of ADP-ribosylation by PARP-1 but also spatially correlated with chromatin-associated ADP-ribose and PARP-1 in Click-ChIP-seq and ChIP-seq assays, respectively. Given these observations, we hypothesized that ADP-ribosylation might modulate NELF function and result altered Pol II pausing. We have explored this possibility using global run-on coupled with deep sequencing (GRO-seq) in MCF-7 cells in which PARP-1 was depleted by RNAi-mediated knockdown. PARP-1 depletion caused an increase in Pol II pausing genome-wide. Taken together, these results suggest the intriguing possibility that ADP-ribosylation of NELF by PARP-1 may be an important and heretofore unknown step in the release of Pol II into productive elongation.
2016-06-09 | GSE74142 | GEO
Project description:The PARP family of proteins comprises 17 members, about two thirds of which are active mono- or poly(ADP-ribosyl)transferase enzymes that transfer the ADP-ribose moiety of NAD+ onto target proteins. In many cases, ADP-ribosylation, which plays critical roles in human diseases (e.g., cancer, heart disease, and neuropathies) is associated with abrogation of the molecular functions of the target. Discerning ADP-ribosylation events mediated by a specific PARP is challenging, since all PARPs use the same substrate (i.e., NAD+) and the available inhibitors lack the specificity needed to make such conclusions. In order to identify the direct and specific targets of individual PARP family members, we have developed a chemical and genetic approach known as analog sensitivity, in which alteration of a single conserved amino acid in the active site of the PARP protein creates a pocket that allows use of an unnatural NAD+ analog containing a steric moiety. We have functionalized the steric moiety with alkyne for use in click chemistry reactions. This approach, which is transferable to other PARP family members, creates substrate specificity where none previously existed, allowing PARP-specific post-translational modification followed by target visualization, or isolation of ADP-ribosylated targets using click chemistry techniques. We have used this technology in conjunction with mass spectrometry to identify hundreds of targets both unique to, as well as shared among, the nuclear PARP proteins, PARP-1, PARP-2, and PARP-3. We have also determined the genome-wide distribution of PARP-1-specific ADP-ribosylation by coupling this analog-sensitive PARP approach with chromatin cross-linking in method that we call “Click-ChIP-seq”. We observed that PARP-1-specific ADP-ribosylation is enriched at transcriptionally active promoters in proximity to sites of PARP-1 enrichment. In addition, we observed that NELF, an important regulator of RNA Polymerase II (Pol II) pausing, is not only a target of ADP-ribosylation by PARP-1 but also spatially correlated with chromatin-associated ADP-ribose and PARP-1 in Click-ChIP-seq and ChIP-seq assays, respectively. Given these observations, we hypothesized that ADP-ribosylation might modulate NELF function and result altered Pol II pausing. We have explored this possibility using global run-on coupled with deep sequencing (GRO-seq) in MCF-7 cells in which PARP-1 was depleted by RNAi-mediated knockdown. PARP-1 depletion caused an increase in Pol II pausing genome-wide. Taken together, these results suggest the intriguing possibility that ADP-ribosylation of NELF by PARP-1 may be an important and heretofore unknown step in the release of Pol II into productive elongation.
2016-06-09 | GSE74141 | GEO
Project description:The macro domain of the histone variant macroH2A1.1 is an evolutionary conserved ADP ribose-binding module of unknown physiological function. We demonstrate that during myogenic differentiation alternative splicing switches the expression of macroH2A1 from the non-ADP ribose binding to the binding isoform. While differentiation commitment is normal in cells lacking macroH2A1.1, we observe two phenotypes: diminished cell fusion correlating with reduced expression of adhesion and migration genes and reduced mitochondrial capacity. While the integrity of the ADP ribose-binding pocket is dispensable for gene regulation and fusion, it is critical to sustain optimal mitochondrial fatty acid oxidation. Rescue experiments using a pharmacological PARP-1 inhibitor and metabolomics support the idea that loss of macroH2A1.1 leads to PARP-1 activation and accelerated NAD+ consumption. As a consequence, the level of nicotinamide mononucleotide, the key metabolite for mitochondrial NAD+ pool regeneration, is reduced and sirtuins fail to maintain mitochondrial proteins in their hypoacetylated and active form. Our results support the idea that chromatin states containing the histone variant macroH2A1.1 contribute to optimal mitochondrial oxidative capacity by channeling the consumption of NAD+ from the nucleus to mitochondria in a manner largely independent on transcriptional regulation.
2017-08-18 | GSE70015 | GEO
Project description:The macro domain of the histone variant macroH2A1.1 is an evolutionary conserved ADP ribose-binding module of unknown physiological function. We demonstrate that during myogenic differentiation alternative splicing switches the expression of macroH2A1 from the non-ADP ribose binding to the binding isoform. While differentiation commitment is normal in cells lacking macroH2A1.1, we observe two phenotypes: diminished cell fusion correlating with reduced expression of adhesion and migration genes and reduced mitochondrial capacity. While the integrity of the ADP ribose-binding pocket is dispensable for gene regulation and fusion, it is critical to sustain optimal mitochondrial fatty acid oxidation. Rescue experiments using a pharmacological PARP-1 inhibitor and metabolomics support the idea that loss of macroH2A1.1 leads to PARP-1 activation and accelerated NAD+ consumption. As a consequence, the level of nicotinamide mononucleotide, the key metabolite for mitochondrial NAD+ pool regeneration, is reduced and sirtuins fail to maintain mitochondrial proteins in their hypoacetylated and active form. Our results support the idea that chromatin states containing the histone variant macroH2A1.1 contribute to optimal mitochondrial oxidative capacity by channeling the consumption of NAD+ from the nucleus to mitochondria in a manner largely independent on transcriptional regulation.
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Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 21 ovarian cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included for eribulin , paclitaxel and untreated cell lines.
2014-10-02 | E-GEOD-50831 | biostudies-arrayexpress
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 27 breast cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included. for eribulin , paclitaxel and untreated cell lines.
2014-10-02 | E-GEOD-50811 | biostudies-arrayexpress
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro. 19 endometrial cancer cell lines treated with eribulin and paclitaxel for 24 hours at concentration 10xIC50. Three technical replicates were included. for eribulin , paclitaxel and untreated cell lines.
2014-10-02 | E-GEOD-50830 | biostudies-arrayexpress
Project description:Eribulin mesylate is a synthetic macrocyclic ketone analog of the marine sponge natural product halichondrin B. Eribulin is a mechanistically unique inhibitor of microtubule dynamics, leading to inhibition of microtubule growth in the absence of effects on microtubule shortening at microtubule plus ends, and formation of nonproductive tubulin aggregates. In this study, we investigated whether selective signal pathways were associated with eribulin activity compared to paclitaxel, which stabilizes microtubules, based on gene expression profiling of cell line panels of breast, endometrial, and ovarian cancer in vitro.
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