P53 Represses the Mevalonate Pathway to Mediate Tumor Suppression
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ABSTRACT:
PROVIDER: PRJNA497787 | ENA |
REPOSITORIES: ENA
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Project description:We have discovered that loss of wild-type p53 correlates with elevated expression of mevalonate pathway genes in murine liver cancer and in human tumors. Mechanistically p53 blocks activation of SREBP-2, the master transcriptional regulator of this pathway, by transcriptionally inducing the ABCA1 cholesterol transporter gene, which inhibits SREBP-2 maturation. In mice the increase in mevalonate gene expression occurs in premalignant p53-null hepatocytes at a stage when p53 is needed to actively suppress tumorigenesis. Either RNAi mediated suppression of key genes in the mevalonate pathway or pharmacological inhibition of its rate-limiting enzyme restricts the development of mouse hepatocellular carcinomas driven by p53 loss. Conversely, like p53 loss, ablation of ABCA1 promotes tumorigenesis in a murine model and is associated with increased SREBP-2 maturation. Our findings thereby demonstrate that repression of the mevalonate pathway is a crucial component of p53-mediated tumor suppression and outline the mechanism by which this occurs.
2018-10-23 | GSE121558 | GEO
Project description: Not available
| S-EPMC6483089 | biostudies-literature
Project description:p53 is a frequent target for mutation in human tumors and previous studies have revealed that these missense mutant proteins can actively contribute to tumorigenesis. To elucidate how mutant p53 might contribute to mammary carcinogenesis we employed a three-dimensional (3D) culture model. In 3D culture non-malignant breast epithelial cells form structures reminiscent of acinar structures found in vivo, whereas breast cancer cells form highly disorganized and in some cases invasive structures. We found that mutant p53 depletion is sufficient to phenotypically revert breast cancer cells to a more acinar-like morphology. Genome-wide expression analysis identified the sterol biosynthesis, or mevalonate, pathway as significantly upregulated by a tumor-derived mutant p53. Using statins and sterol biosynthesis intermediates, we demonstrate that this pathway is both necessary and sufficient for the phenotypic effects of mutant p53 on breast tissue architecture. Mutant p53 associates with the sterol gene promoters at least partly via the SREBP transcription factors. Finally, p53 mutation correlates with higher levels of sterol biosynthesis genes in human breast tumors. This activity of mutant p53 not only contributes insight into breast carcinogenesis, but also implicates the mevalonate pathway as a new therapeutic target for tumors bearing such mutations in p53. RNA was isolated from three independent experiments of MDA-468.shp53 cells cultured under 3D conditions for 8 days in the presence or absence of DOX, reversed transcribed and hybridized to an Affymetrix GeneChip expression array. Data was processed using the Robust Multichip Average (RMA) algorithm to give expression signals and paired t-test was applied for each probe. Probes with 1% significance were selected for Ingenuity Pathway Analysis.
2012-02-13 | E-GEOD-31812 | biostudies-arrayexpress
Project description:p53 is a frequent target for mutation in human tumors and previous studies have revealed that these missense mutant proteins can actively contribute to tumorigenesis. To elucidate how mutant p53 might contribute to mammary carcinogenesis we employed a three-dimensional (3D) culture model. In 3D culture non-malignant breast epithelial cells form structures reminiscent of acinar structures found in vivo, whereas breast cancer cells form highly disorganized and in some cases invasive structures. We found that mutant p53 depletion is sufficient to phenotypically revert breast cancer cells to a more acinar-like morphology. Genome-wide expression analysis identified the sterol biosynthesis, or mevalonate, pathway as significantly upregulated by a tumor-derived mutant p53. Using statins and sterol biosynthesis intermediates, we demonstrate that this pathway is both necessary and sufficient for the phenotypic effects of mutant p53 on breast tissue architecture. Mutant p53 associates with the sterol gene promoters at least partly via the SREBP transcription factors. Finally, p53 mutation correlates with higher levels of sterol biosynthesis genes in human breast tumors. This activity of mutant p53 not only contributes insight into breast carcinogenesis, but also implicates the mevalonate pathway as a new therapeutic target for tumors bearing such mutations in p53.
2012-02-13 | GSE31812 | GEO
Project description:In this study, we have investigated the effect of p53 deletion on the metabolic activity of colon cancer cells exposed to metabolic stress. In order to recreate the simultaneous reduction in oxygen and nutrient availability found in tumors, we cultured cancer cells as multicellular tumor spheroids. Under these conditions, p53 deficient cancer cells activate the expression of enzymes of the mevalonate pathway via the sterol regulatory element binding protein 2 (SREBP2). Moreover, inhibition of mevalonate pathway activity with statins selectively induced apoptosis in p53 deficient cancer cells exposed to metabolic stress. This effect was mediated by the requirement of p53 deficient cancer cells to synthesise ubiquinone (coenzyme Q10) to maintain TCA cycle activity, respiration and the production of pyrimidine nucleotides. Our study has revealed a novel link between isoprenoid synthesis by the mevalonate pathway and the electron transport function of ubiquinone, which is required for nucleotide biosynthesis. As a consequence, maintaining mevalonate pathway activity is essential for p53 deficient cancer cells to proliferate and survive under the metabolic constraints of the tumor microenvironment.
2019-11-15 | GSE124189 | GEO
Project description:p53 directly represses human LINE1 transposons
| PRJNA667740 | ENA
Project description:The microRNA (miR) miR-874, a potential tumour suppressor, causes cell death via target gene suppression in various cancer types. Mevalonate pathway inhibition also causes cell death in breast cancer. However, the relationship between the mevalonate pathway and miR-874-induced apoptosis or its association with the tumour suppressor p53 has not been elucidated. We identified phosphomevalonate kinase (PMVK), a key mevalonate pathway enzyme, and sterol regulatory element-binding factor 2 (SREBF2), the master cholesterol biosynthesis regulator, as direct miR‑874 targets. Next-generation sequencing analysis revealed a significant miR-874–mediated downregulation of PMVK and SREBF2 gene expression and p53 pathway enrichment. Luciferase reporter assays showed that miR-874 directly regulated PMVK and SREBF2. miR-874–induced apoptosis was p53 dependent, and single-cell RNA sequencing analysis demonstrated that miR-874 transfection resulted in apoptosis and p53 pathway activation. Downregulation of PMVK expression also caused cell cycle arrest and p53 pathway activation, which was rescued by geranylgeranyl pyrophosphate (GGPP) supplementation. Analysis of The Cancer Genome Atlas (TCGA) database indicated a negative correlation between miR-874 and PMVK expression and between miR-874 and SREBF2 expression. These findings suggest that miR-874 suppresses the mevalonate pathway by targeting SREBF2 and PMVK, resulting in GGPP depletion, which activates the p53 pathway and promotes cycle arrest or apoptosis.
2022-10-03 | GSE214508 | GEO
Project description:The microRNA (miR) miR-874, a potential tumour suppressor, causes cell death via target gene suppression in various cancer types. Mevalonate pathway inhibition also causes cell death in breast cancer. However, the relationship between the mevalonate pathway and miR-874-induced apoptosis or its association with the tumour suppressor p53 has not been elucidated. We identified phosphomevalonate kinase (PMVK), a key mevalonate pathway enzyme, and sterol regulatory element-binding factor 2 (SREBF2), the master cholesterol biosynthesis regulator, as direct miR‑874 targets. Next-generation sequencing analysis revealed a significant miR-874–mediated downregulation of PMVK and SREBF2 gene expression and p53 pathway enrichment. Luciferase reporter assays showed that miR-874 directly regulated PMVK and SREBF2. miR-874–induced apoptosis was p53 dependent, and single-cell RNA sequencing analysis demonstrated that miR-874 transfection resulted in apoptosis and p53 pathway activation. Downregulation of PMVK expression also caused cell cycle arrest and p53 pathway activation, which was rescued by geranylgeranyl pyrophosphate (GGPP) supplementation. Analysis of The Cancer Genome Atlas (TCGA) database indicated a negative correlation between miR-874 and PMVK expression and between miR-874 and SREBF2 expression. These findings suggest that miR-874 suppresses the mevalonate pathway by targeting SREBF2 and PMVK, resulting in GGPP depletion, which activates the p53 pathway and promotes cycle arrest or apoptosis.
2022-10-03 | GSE214507 | GEO
Project description:p53 is a potent tumor suppressor and commonly mutated in human cancers. Recently, we demonstrated that p53 genes act to restrict retrotransposons in germ line tissues of flies and fish but whether this activity is conserved in somatic human cells is not known. Here we show that p53 constitutively restrains human LINE1s by cooperatively engaging sites in the 5’UTR and stimulating local deposition of repressive histone marks at these transposons. Consistent with this, the elimination of p53 or the removal of corresponding binding sites in LINE1s, prompted these retroelements to become hyperactive. Concurrently, p53 loss instigated chromosomal rearrangements linked to LINE sequences and also provoked inflammatory programs that were dependent on reverse transcriptase produced from LINE1s. Taken together, our observations establish that p53 continuously operates at the LINE1 promoter to restrict autonomous copies of these mobile elements in human cells. Our results further suggest that constitutive restriction of these retroelements may help to explain tumor suppression encoded by p53, since erupting LINE1s produced acute oncogenic threats when p53 was absent.
2020-12-01 | GSE159134 | GEO
Project description:The tumor suppressor p53 is mutated in the majority of human cancers, including pancreatic ductal adenocarcinoma (PDAC)1,2. Wild-type p53 accumulates in response to cellular stress and acts to regulate the expression of genes that influence cell fate and constrain tumorigenesis2. p53 also can modulate cellular metabolism3, though it remains unclear how the metabolic effects of p53 influence tumor suppression or whether the metabolic consequences of p53 loss play a role in disease maintenance. Here, we show that restoring endogenous p53 function in cancer cells derived from a mouse model of PDAC driven by oncogenic Kras and a regulatable p53 short hairpin RNA (shRNA) rewires glucose and glutamine metabolism to support the accumulation of the metabolite alpha-ketoglutarate, an obligate substrate for several enzymes that regulate chromatin methylation. p53 restoration induces transcriptional programs characteristic of pre-neoplastic differentiation, an effect that can be partially recapitulated by addition of cell permeable alpha-ketoglutarate. Consequently, enforcing alpha-ketoglutarate accumulation in p53 deficient cells by inhibiting expression of oxoglutarate dehydrogenase (Ogdh), the enzyme that consumes alpha-ketoglutarate in the tricarboxylic acid cycle, reduces tumor-initiating capacity and promotes tumor differentiation in vivo. In both mouse and human pancreatic cancer, decreasing levels of the alpha-ketoglutarate-dependent chromatin modification 5-hydroxymethylcytosine (5hmC) marks progression from prenoplastic to de-differentiated malignant lesions. p53 restoration or Ogdh suppression promotes accumulation of 5hmC specifically in differentiated tumor cells in vivo. Together, these results nominate alpha-ketoglutarate as an effector of p53-mediated tumor suppression that promotes pre-neoplastic differentiation and suppresses malignant progression.
2019-09-09 | GSE114263 | GEO