Transcriptome profiling of wild-type (WT) and USP8 knockout (KO) CT26 cell lines
Ontology highlight
ABSTRACT: USP8 is one of DUBs and is frequently overexpressed or gain-of-function mutated in multiple types of human cancer. Importantly, USP8 has been identified as an immunomodulatory DUB as T cell-specific Usp8 deficiency disrupts regulatory T cell functions, leading to recruiting abundant CD8+ T cells in colons and resulting in the inflammatory bowel disease in mice. However, whether targeting USP8 can enhance anti-tumor immunity has not been reported. To further explore the physiological function of USP8, we performed the transcriptomic analysis to comprehensively understand which signaling pathways are mainly regulated by USP8 in cancer cells. Usp8 WT and KO CT26 cells were harvested for RNA-sequencing (RNA-seq).
Project description:We show that USP8 colocalizes with intracellular Mtb, recognizes phagosomal membrane damage, and is required for ESCRT-dependent membrane repair. Furthermore, USP8 regulates the NRF2-dependent antioxidant signature. Taken together, our study shows a central role of USP8 in promoting intracellular growth of Mtb by coordinating phagosomal membrane repair, ubiquitin-driven selective autophagy, and the oxidative stress response.
Project description:The ubiquitination and proteasome-mediated degradation of Hypoxia Inducible Factors (HIFs) is central to metazoan oxygen-sensing, but the involvement of deubiquitinating enzymes (DUBs) in HIF signalling is less clear. Here, using a bespoke DUBs sgRNA library we conduct CRISPR/Cas9 mutagenesis screens to determine how DUBs are involved in HIF signalling. Alongside defining DUBs involved in HIF activation or suppression, we identify USP43 as a DUB required for efficient activation of a HIF response. USP43 is hypoxia regulated and selectively associates with the HIF-1 isoform, and while USP43 does not alter HIF-1 stability, it facilitates HIF-1 nuclear accumulation and binding to its target genes. Mechanistically, USP43 associates with 14-3-3 proteins in a hypoxia-dependent manner to increase the nuclear pool of HIF-1, independently of DUB activity. Together, our results unveil the DUB landscape in HIF signalling, and highlight the multifunctionality of DUBs, illustrating that they can provide important signalling roles outside of their catalytic activity.
Project description:The ubiquitination and proteasome-mediated degradation of Hypoxia Inducible Factors (HIFs) is central to metazoan oxygen-sensing, but the involvement of deubiquitinating enzymes (DUBs) in HIF signalling is less clear. Here, using a bespoke DUBs sgRNA library we conduct CRISPR/Cas9 mutagenesis screens to determine how DUBs are involved in HIF signalling. Alongside defining DUBs involved in HIF activation or suppression, we identify USP43 as a DUB required for efficient activation of a HIF response. USP43 is hypoxia regulated and selectively associates with the HIF-1 isoform, and while USP43 does not alter HIF-1 stability, it facilitates HIF-1 nuclear accumulation and binding to its target genes. Mechanistically, USP43 associates with 14-3-3 proteins in a hypoxia-dependent manner to increase the nuclear pool of HIF-1, independently of DUB activity. Together, our results unveil the DUB landscape in HIF signalling, and highlight the multifunctionality of DUBs, illustrating that they can provide important signalling roles outside of their catalytic activity.
Project description:Background: USP8 mutations are the most common driver changes in corticotroph pituitary tumors. They have direct effect on cells’ proteome through disturbance of ubiquitination process and also influence gene expression. The aim of this study was to compare microRNA profiles in USP8- mutated and wild-type tumors and determine the probable role of differential microRNA expression by integrative microRNA and mRNA analysis. Methods: Patients with Cushing’s disease (n = 28) and silent corticotroph tumors (n = 20) were included. USP8 mutations were identified with Sanger sequencing. MicroRNA and gene expression was determined with next-generation sequencing. Results: USP8-mutated patients with Cushing’s disease showed higher rate of clinical remission and trend towards lower tumor volume than wild-type patients. Comparison of microRNA profiles of USP8-mutated and wild-type tumors revealed 68 differentially expressed microRNAs. Their target genes were determined by in silico prediction and microRNA/mRNA correlation analysis. GeneSet Enrichment analysis of putative targets showed that the most significantly overrepresented genes are involved in protein ubiquitination-related processes. Only few microRNAs influence the expression of genes differentially expressed between USP8-mutated and wild-type tumors. Conclusions: Differences in microRNA expression in corticotropinomas stratified according to USP8 status reflect disturbed ubiquitination processes, but do not correspond to differences in gene expression between these tumors.
Project description:Over half of ovarian clear cell carcinoma (OCCC) cases exhibit deficiencies in the ARID1A gene, a chromatin remodeling complex component. OCCC is resistant to chemotherapy and challenging to treat, necessitating new drug treatment strategies. This study used a publicly available dependency factor database to identify synthetic lethal targets for ARID1A-deficient cancer. The DepMap portal was used to identify genes on which ARID1A-deficient cancer cell lines are highly dependent. Our analysis limited to ovarian cancer cell lines only identified the deubiquitinating enzyme USP8 as a synthetic lethal target in ARID1A-deficient OCCC cancer cell lines and mouse xenograft models. In addition, USP8 inhibitors were more selective for ARID1A-deficient cells than existing candidate drugs used in promising clinical trials for ARID1A-deficient cancers. Suppression of USP8 in ARID1A-deficient cells led to degradation of FGFR2 via the proteasome. Deficiency of ARID1A causes abnormalities in the STAT3 pathway, which is one of the downstream pathways of FGFR2, but suppression of USP8 attenuates phosphorylation of STAT3 pT705 and induces apoptosis. Taken together, the data suggest that USP8 is a novel therapeutic target for ARID1A-deficient OCCC and that it suppresses FGFR2-STAT3 signaling.
Project description:Goal: Microsatellite-instable (MSI) tumors are one of the few cancers that respond to immune checkpoint blockade (ICB); however, the mechanism of MSI status development is unclear. Here, we report that protein phosphatase 2A (PP2A) deletion or inactivation converted cold microsatellite-stable (MSS) into MSI tumors. Objectives: Using RNA sequencing data of three CT26-shppp2r1a data and a CT26-scr data, we demonstrate that these intestinal tumors display differential core driver pathways.
Project description:Enzymes that bind and process ubiquitin, a small 76 amino acid protein, have been recognized as pharmacological targets in oncology, immunological disorders and neurodegeneration. Mass spectrometry technology has now reached the capacity to cover the proteome with enough depth to interrogate entire biochemical pathways including those that contain DUBs and E3 ligase substrates. We have recently characterized the breast cancer cell (MCF7) deep proteome by detecting and quantifying ~10,000 proteins, and within this data set, we can detect endogenous expression of 65 deubiquitylating enzymes (DUBs), whereas matching transcriptomics detected 78 DUB mRNAs. Since enzyme activity provides another meaningful layer of information in addition of the expression levels, we have combined advanced mass spectrometry technology, pre-fractionation and more potent/selective ubiquitin active-site probes with propargyl based electrophiles to profile 74 DUBs including distinguishable isoforms for five DUBs in MCF7 crude extract material. Competition experiments with cysteine alkylating agents, pan-DUB inhibitors ubiquitin combined with probe labelling revealed the proportion of active cellular DUBs directly engaged with probes by label-free quantitative (LFQ) mass spectrometry, demonstrating that USP13, 39 and USP40 are non-reactive to probe, reflecting no, low or restricted enzymatic activity under these cellular conditions. Our extended chemoproteomics workflow increases depth of covering the active DUBome, including isoform-specific resolution, and provides the framework for more comprehensive cell-based small molecule DUB selectivity profiling.