USP28 controls SREBP2 and the mevalonate pathway to drive tumour growth in squamous cancer
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA841983 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR19379000.fastq.gz | Fastqsanger.gz | |||
| SRR19379001.fastq.gz | Fastqsanger.gz | |||
| SRR19379002.fastq.gz | Fastqsanger.gz | |||
| SRR19379003.fastq.gz | Fastqsanger.gz | |||
| SRR19378989.fastq.gz | Fastqsanger.gz |
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Project description:SREBP2 controls the expression of enzymes involved in the mevalonate pathway (MVP), a biosynthetic process that drives the synthesis of dolichol, heme A, ubiquinone and cholesterol but also provides substrates for protein prenylation, and that is frequently deregulated in cancer. We show here that SREBP2 is a novel substrate for the deubiquitinating enzyme USP28 and that USP28 regulates SREBP2 stability independent of FBXW7. Inhibition of USP28 reduces MVP activity and renders cancer cells highly sensitive to MVP inhibition by statins. Moreover, statin sensitivity of USP28 depleted cells was rescued by the addition of geranyl-geranyl-pyrophosphate, a substrate for protein prenylation. We also provide evidence that SREBP2 participates in the regulation of gene expression signature associated with squamous cell carcinoma (SCC) and that SREBP2 and enzymes of the MVP are overexpressed in SCC from different tissue origins. Finally, deletion of SREBP2 attenuated tumour growth in a mouse model of lung cancer. Our findings suggest that SREBP2 is a novel substrate for USP28 and that combinatorial targeting of the MVP together with USP28 inhibition could be a therapeutic strategy for the treatment of squamous cell carcinomas.
2023-05-16 | GSE204703 | GEO
Project description:SREBP2 is a master regulator of the mevalonate pathway (MVP), a biosynthetic process that drives the synthesis of dolichol, heme A, ubiquinone and cholesterol and also provides substrates for protein prenylation. Here, we identify SREBP2 as a novel substrate for USP28, a deubiquitinating enzyme that is frequently upregulated in squamous cancers. Our results show that silencing of USP28 reduces expression of MVP enzymes and lowers metabolic flux into this pathway. We also show that USP28 binds to mature SREBP2, leading to its deubiquitination and stabilisation. USP28 depletion rendered cancer cells highly sensitive to MVP inhibition by statins, which was rescued by the addition of geranyl-geranyl pyrophosphate. Analysis of human tissue microarrays revealed elevated expression of USP28, SREBP2 and MVP enzymes in lung squamous cell carcinoma (LSCC) compared to lung adenocarcinoma (LADC). Moreover, CRISPR/Cas-mediated deletion of SREBP2 selectively attenuated tumour growth in a KRas/p53/LKB1 mutant mouse model of lung cancer. Finally, we demonstrate that statins synergise with a dual USP28/25 inhibitor to reduce viability of SCC cells. Our findings suggest that combinatorial targeting of MVP and USP28 could be a therapeutic strategy for the treatment of squamous cell carcinomas.
| S-EPMC10307777 | biostudies-literature
Project description:The oncoprotein ∆Np63 is an essential transcriptional master- and cell identity regulator in squamous cell carcinoma (SCC) of various origins, encompassing lung, head and neck, oesophagus, cervix and skin. While in non-transformed cells ∆Np63 protein abundance is tightly regulated by the ubiquitin proteasome system (UPS), in tumours E3-ligases ubiquitylating ∆Np63, such as FBXW7, are commonly mutated or lost, resulting in a hyper-stabilisation of the oncogenic driver. Targeting ∆Np63 protein abundance in SCC could present a possible therapeutic avenue. Here, we report that the deubiquitylase USP28 regulates ∆Np63 protein stability and abundance in SCC by counteracting the degradative UPS system. Interference with USP28 activity by pharmacological inhibition specifically affected human SCC cell lines and, finally, we were able to demonstrate in vivo using CRISPR/Cas9 mouse models that Usp28 is required for SCC induction and maintenance. Hence, targeting USP28 is a viable option to tackle ∆Np63 protein abundance in SCC tumours.
2020-03-04 | GSE129982 | GEO
Project description:A USP28-∆Np63 axis is a druggable vulnerability of squamous tumour formation and maintenance
| PRJNA533329 | ENA
Project description:Usp28-KO HLF cell lines were generated by CRISPR-Cas9. Usp28-KO cells expressing Usp28-WT, Usp28-Mono or a control vector were established by lentiviral transduction.
2023-09-30 | GSE213892 | GEO
Project description:Fbw7, the substrate recognition subunit of SCF(Fbw7) ubiquitin ligase, mediates turnover of multiple proto-oncoproteins and promotes its own degradation. Fbw7-mediated substrate degradation is antagonized by the Usp28 deubiquitinase. We now show, using knockout mice, that Usp28 preferentially deubiquitinates and stabilizes Fbw7. Monoallelic deletion of Usp28 maintains stable Fbw7 but destabilizes Fbw7 substrates. In contrast, complete knockout of Usp28 promotes Pin1-dependent autocatalytic turnover of Fbw7, accumulation of Fbw7 substrates and oncogenic transformation. Overexpression of Usp28 stabilizes both Fbw7 and its substrates and similarly enhances transformation. We propose that dual regulation of Fbw7 activity by Usp28 maintains physiological levels of Fbw7 substrates, and that both loss and overexpression of Usp28 in human cancer promote Fbw7 substrate accumulation. RNAseq experiments of E13.5 murine embryonic fibroblasts (MEFs) derived from animals in which Usp28 was either deleted (-/-), wildtype (+/+) or heterozygous (+/-). In a first set of experiments immortalized MEFs of all three genotypes were analysed in biological triplicates. In a second set of experiments immortalized and Ras transformed MEFs of all three genotypes and MEFs which overexpress USP28 (+/+/+) where sequenced in duplicates.
2015-05-01 | E-GEOD-59354 | biostudies-arrayexpress
Project description:Lung squamous cell carcinoma (LSCC) is a considerable global health burden, with an incidence of over 600,000 cases per year. Treatment options are limited, and patient 5-year survival rate is less than 5%. The ubiquitin specific protease 28 (USP28) has been implicated in tumorigenesis through its stabilization of the oncoprotein c-MYC. Here, we show that genetic inactivation of USP28 induced regression of established murine LSCC lung tumors. We developed small molecule USP28 inhibitors that inhibit USP28 activity in the low nanomole range. While displaying considerable activity against the closest homologue USP25, these inhibitors showed a high degree of selectivity over other deubiquitinases. USP28 inhibitor treatment resulted in a dramatic decrease in c-Myc proteins levels and consequently induced substantial regression of autochthonous murine LSCC tumors and human LSCC xenografts, thereby phenocopying the effect observed by genetic deletion. Thus, USP28 may represent a promising therapeutic target for the treatment of squamous cell lung carcinoma.
2024-07-30 | PXD023339 | Pride
Project description:Fbw7, the substrate recognition subunit of SCF(Fbw7) ubiquitin ligase, mediates turnover of multiple proto-oncoproteins and promotes its own degradation. Fbw7-mediated substrate degradation is antagonized by the Usp28 deubiquitinase. We now show, using knockout mice, that Usp28 preferentially deubiquitinates and stabilizes Fbw7. Monoallelic deletion of Usp28 maintains stable Fbw7 but destabilizes Fbw7 substrates. In contrast, complete knockout of Usp28 promotes Pin1-dependent autocatalytic turnover of Fbw7, accumulation of Fbw7 substrates and oncogenic transformation. Overexpression of Usp28 stabilizes both Fbw7 and its substrates and similarly enhances transformation. We propose that dual regulation of Fbw7 activity by Usp28 maintains physiological levels of Fbw7 substrates, and that both loss and overexpression of Usp28 in human cancer promote Fbw7 substrate accumulation.
2015-05-01 | GSE59354 | GEO
Project description:Mitochondrial dysfunction induces a strong adaptive retrograde signaling response, however many of the down-stream effectors remain to be discovered. Here, we studied the shared transcriptional responses to three different mitochondrial respiratory chain inhibitors in human primary skin fibroblasts using QuantSeq 3’RNA-sequencing. We found that mevalonate pathway genes were concurrently downregulated irrespective of the respiratory chain complex affected. Targeted metabolomics demonstrated that impaired mitochondrial respiration at any of the three affected complexes also had functional consequences on the mevalonate pathway, reducing cholesterol precursor metabolites. A deeper study of complex I inhibition showed a reduced activity of ER-bound sterol sensing enzymes through impaired processing of the transcription factor SREBP2 and accelerated degradation of the ER cholesterol sensors SQLE and HMGCR. These adaptations of mevalonate pathway activity neither affected total intracellular cholesterol levels nor the cellular free (non-esterified) cholesterol pool. Measurement of intracellular cholesterol using the fluorescent cholesterol binding dye filipin revealed that complex I inhibition elevated cholesterol on intracellular compartments. Our study shows that mitochondrial respiratory chain dysfunction elevates intracellular free cholesterol levels and therefore attenuates the expression of mevalonate pathway enzymes, which lowers endogenous cholesterol biosynthesis, disrupting the metabolic output of the mevalonate pathway. Intracellular disturbances in cholesterol homeostasis may alter systemic cholesterol management in diseases associated with declining mitochondrial function.
2022-02-25 | GSE191034 | GEO
Project description:The active form of the SREBP2 transcription factor was specifically overexpressed in the intesitne. This was achieved by generating transgenic mouse model (designated as ISR2) in which the transgene represents the N-terminal active SREBP2 transcription factor driven by the villin promoter. In this project, we investigated the effects of overactivation of SREBP2 on gene expression in mouse jejunum Gene expression profile in the jejunum of ISR2 was compared to gene expression profile in the jejunum of their wild type littermates.
2013-10-26 | E-GEOD-51736 | biostudies-arrayexpress