Inhibition of DUSP18 impairs cholesterol biosynthesis and promotes anti-tumor immunity in colorectal cancer
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1101055 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Tumor cells reprogram their metabolism to produce specialized metabolites that both fuel their own growth and license tumor immune evasion. However, the relationships between these functions remain poorly understood. Here, we report CRISPR screens in a mouse model of colo-rectal cancer (CRC) that implicates the dual specificity phosphatase 18 (DUSP18) in the establishment of tumor-directed immune evasion. Dusp18 inhibition reduces CRC growth rates, which correlate with high levels of CD8+ T cell activation. Mechanistically, DUSP18 dephosphorylates and stabilizes the USF1 bHLH-ZIP transcription factor. In turn, USF1 induces the SREBF2 gene, which allows cells to accumulate the cholesterol biosynthesis intermediate lanosterol and release it into the tumor microenvironment (TME). There, lanosterol uptake by CD8+ T cells suppresses the mevalonate pathway and reduces KRAS protein prenylation and function, which in turn inhibits their activation and establishes a molecular basis for tumor cell immune escape. Finally, the combination of an anti-PD-1 antibody and Lumacaftor, an FDA-approved small molecule inhibitor of DUSP18, inhibits CRC growth in mice and synergistically enhances anti-tumor immunity. Collectively, our findings support the idea that a combination of immune checkpoint and metabolic blockade represents a rationally-designed, mechanistically-based and potential therapy for CRC.
| S-EPMC11239938 | biostudies-literature
Project description:To explore the role of Dusp18 in regulating the immune microenvironment of colorectal cancer (CRC), we established MC38 knockdown via shRNA and performed the proteomics.
2024-07-12 | PXD053284 | Pride
Project description:We discovered, through mining TCGA data and conducting CRISPR screens, that DUSP18 expression within tumor cells significantly influences the immune microenvironment of colorectal cancer.To explore the role of DUSP18 in regulating the immune microenvironment of colorectal cancer (CRC), we established MC38 and HCT116 cell lines with targeted gene knockdown via shRNA and performed RNA-Seq.
2024-06-21 | GSE264145 | GEO
Project description:Intricate regulatory networks govern the net balance of cholesterol biosynthesis, uptake and efflux; however, the mechanisms surrounding cholesterol homeostasis remain incompletely understood. Here, we develop an integrative genomic strategy to detect regulators of LDLR activity and identify 250 genes whose knockdown affects LDL-cholesterol uptake and whose expression is modulated by intracellular cholesterol levels in human hepatic cells. From these hits, we focus on MMAB, an enzyme which catalyzes the conversion of vitamin B12 to adenosylcobalamin, and whose expression has previously been linked to altered levels of circulating cholesterol in humans. We demonstrate that hepatic levels of MMAB are modulated by dietary and cellular cholesterol levels through SREBP2, the master transcriptional regulator of cholesterol homeostasis. Knockdown of MMAB decreases intracellular cholesterol levels and augments SREBP2-mediated gene expression and LDL-cholesterol uptake in human and mouse hepatic cell lines. Reductions in total sterol content were attributed to increased intracellular levels of propionic and methylmalonic acid and subsequent inhibition of HMGCR activity and cholesterol biosynthesis. Moreover, mice treated with antisense inhibitors of MMAB display a significant reduction in hepatic HMGCR activity and hepatic sterol content and increased expression of SREBP2-mediated genes. Collectively, these findings reveal an unexpected role for the adenosylcobalamin pathway in regulating LDLR expression and identify MMAB as an additional control point by which cholesterol biosynthesis is regulated by its end product.
2021-06-01 | GSE169712 | GEO
Project description:Intricate regulatory networks govern the net balance of cholesterol biosynthesis, uptake and efflux; however, the mechanisms surrounding cholesterol homeostasis remain incompletely understood. Here, we develop an integrative genomic strategy to detect regulators of LDLR activity and identify 250 genes whose knockdown affects LDL-cholesterol uptake and whose expression is modulated by intracellular cholesterol levels in human hepatic cells. From these hits, we focus on MMAB, an enzyme which catalyzes the conversion of vitamin B12 to adenosylcobalamin, and whose expression has previously been linked with altered levels of circulating cholesterol in humans. We demonstrate that hepatic levels of MMAB are modulated by dietary and cellular cholesterol levels through SREBP2, the master transcriptional regulator of cholesterol homeostasis. Knockdown of MMAB decreases intracellular cholesterol levels and augments SREBP2-mediated gene expression and LDL-cholesterol uptake in human and mouse hepatic cell lines. Reductions in total sterol content were attributed to increased intracellular levels of propionic and methylmalonic acid and subsequent inhibition of HMGCR activity and cholesterol biosynthesis. Moreover, mice treated with antisense inhibitors of MMAB display a significant reduction in hepatic HMGCR activity, hepatic sterol content and increased expression of SREBP2-mediated genes. Collectively, these findings reveal an unexpected role for the adenosylcobalamin pathway in regulating LDLR expression and identify MMAB as an additional control point by which cholesterol biosynthesis is regulated by its end product.
2021-09-10 | GSE183790 | GEO
Project description:Background: Several genetic defects of the nucleotide excision repair (NER) pathway, including deficiency of the Excision Repair Cross-Complementing rodent repair deficiency, complementation group 1 (ERCC1), result in pre-mature aging, impaired growth, microcephaly and delayed development of the cerebellum. Such a phenotype also occurs in ERCC1-knockout mice which survive for up to 4 weeks after birth. Therefore, we analyzed cerebellar and hippocamapal transcriptomes of these animals at 3 weeks of age to identify the candidate mechanisms underlying brain consequences of reduced ERCC1 activity. Results: In the cerebellum, the most prominent change was upregulation of genes that are associated with gliosis. Although Purkinje cell degeneration has been reported in some mouse strains with NER impairment, Purkinje cell transcriptome was mostly unaffected by the ERCC1 knockout. In the hippocampus, the gliosis response was minimal. Instead, there was an extensive downregulation of genes related to lipid metabolism including several enzymes of the cholesterol biosynthesis pathway as well as lipoproteins and plasma membrane proteins. Reduced expression of the cholesterol biosynthesis pathway genes was also present in the neocortex of adult mice whose ERCC1 gene was replaced by a mutant allele with a partial activity. Conclusions: Downregulation of forebrain cholesterol biosynthesis genes is a newly identified consequence of ERCC1 deficiency. Its presence in adult mice suggests that it is not a secondary consequence of brain growth impairment. Instead, reduced cholesterol biosynthesis may contribute to such an impairment as well as affect function of mature synapses. We analyzed the hippocampus and cerebellum from three Ercc1-/- and three WT littermates using the Affymetrix Mouse Genome 430_2.0. Data was analyzed using the dChip DNA-Chip analyzer software .
2011-08-15 | E-GEOD-31199 | biostudies-arrayexpress
Project description:Negative Feedback Regulation of Cholesterol Biosynthesis by MMAB
| PRJNA717749 | ENA
Project description:Cholesterol deprivation drives DHEA biosynthesis in human adrenals
| PRJNA789937 | ENA
Project description:Negative Feedback Regulation of Cholesterol Biosynthesis by MMAB
| PRJNA762016 | ENA
Project description:Many enveloped viruses bud from cholesterol-rich lipid rafts on the cell membrane. Depleting cellular cholesterol impedes this process and results in viral particles with reduced viability. Viperin (virus inhibitory protein endoplasmic reticulum-associated, interferon-induced) is an ER membrane-associated enzyme that when expressed in response to viral infections exerts broad-ranging antiviral effects, including inhibiting the budding of some enveloped viruses. Here we have investigated the effect of viperin expression on cholesterol biosynthesis. We found that viperin expression reduces cholesterol levels by 20 – 30 % in HEK293T cells. A proteomic screen of the viperin interactome identified several cholesterol biosynthetic enzymes among the top hits. The two most highly enriched proteins were lanosterol synthase and squalene monooxygenase, enzymes that catalyze key steps establishing the sterol carbon skeleton. Co-immunoprecipitation experiments established that viperin, lanosterol synthase and squalene monooxygenase form a complex at the ER membrane. Co-expression of viperin was found to significantly inhibit the specific activity of lanosterol synthase in HEK293T cell lysates. Co-expression of viperin had no effect on the specific activity of squalene monooxygenase, but reduced its expression levels in the cells by approximately 30 %. Despite these inhibitory effects, co-expression of either LS or SM failed to reverse the viperin-induced depletion of cellular cholesterol levels in HEK293T cells. Our results establish a clear link between the down-regulation of cholesterol biosynthesis and viperin, although at this point the effect cannot be unambiguously attributed interactions between viperin and a specific biosynthetic enzyme.
2021-09-10 | PXD023999 | Pride