Genetic Adaptation of a Mevalonate Pathway Deficient Mutant in Staphylococcus aureus
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PROVIDER: PRJNA544513 | ENA |
REPOSITORIES: ENA
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Project description:In this study we addressed the question how a mevalonate (MVA)-auxotrophic Staphylococcus aureus ΔmvaS mutant can revert to prototrophy.
2020-05-31 | GSE131722 | GEO
Project description:In this study we addressed the question how a mevalonate (MVA)-auxotrophic Staphylococcus aureusΔmvaS mutant can revert to prototrophy. This mutant couldn't grow in the absence of MVA. However, after a long lag-phase of 4-6 days the mutant adapted from auxotrophic to prototrophic phenotype. During that time, it acquired two point mutations: One mutation in the coding region of the regulator gene spx, which resulted in an amino acid exchange that decreased Spx function. The other mutation in the upstream-element within the core-promoter of the mevalonolactone lactonase gene drp35. This mutation led to an increased expression of drp35. In repeated experiments the mutations always occurred in spx and drp35 and in the same order. The first detectable mutation appeared in spx and allowed slight growth; the second mutation, in drp35, increased growth further. Phenotypical characterizations of the mutant showed that small amounts of the lipid-carrier undecaprenol are synthesized, despite the lack of mvaS. The growth of the adapted clone, ΔmvaSad, indicates that the mutations reawake a rescue bypass. We think that this bypass enters the MVA pathway at the stage of MVA, because blocking the pathway downstream of MVA led to growth arrest of the mutant. In addition, the lactonase Drp35 is able to convert mevalonolactone to MVA. Summarized, we describe here a mutation-based two-step adaptation process that allows resuscitation of growth of the ΔmvaS mutant.
| S-EPMC6052127 | biostudies-literature
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:Metastasis is an important factor affecting the prognosis and survival of bladder cancer (BLCA) patients. Our previous study found that the mevalonate pathway is associated with the migratory ability of BLCA cells, but the exact mechanism is unclear. Here, we found that BLCA patients with mevalonate pathway activation had a poorer prognosis. Inhibition of the mevalonate pathway (FDPS knockdown, simvastatin or zoledronic acid) significantly reduced the migratory ability of BLCA cells. Therefore, we tested the changes of key genes after knocking down the key enzymes of the mevalonate pathway, FDPS and SQLE1, and the transcription factor YY1 in bladder cancer cells using RNA sequencing.
2024-09-08 | GSE252007 | GEO
Project description:Simvastatin has been widely used for treatment of hypercholesterolemia due to its ability to inhibit HMG-CoA reductase, the rate limiting enzyme of de novo cholesterol synthesis via mevalonate pathway. Its inhibitory action causes also depletion of pathway intermediates, farnesyl pyrophosphate (FPP) and geranyl-geranyl pyrophosphate (GGPP), which are inevitable for proper targeting of small GTPases (e.g. Ras proteins) to their site of action. We profiled by array the gene expression of MIA PaCa-2 cells treated with simvastatin, FPP, GGPP and their combinations. The inhibitory effect of statins on GFP-K-Ras protein trafficking were partially prevented by addition of the mevalonate pathway intermediates. We conclude that the anticancer effect of simvastatin is to a large extent mediated through isoprenoid intermediates of the mevalonate pathway.
2018-03-31 | E-MTAB-3263 | 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. 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:Isoprenoids are a class of ubiquitous organic molecules synthesized from the five-carbon starter unit isopentenyl pyrophosphate (IPP). Comprising more than 30,000 known natural products, isoprenoids serve various important biological functions in many organisms. In bacteria, undecaprenyl pyrophosphate is absolutely required for the formation of cell wall peptidoglycan and other cell surface structures, while ubiquinones and menaquinones, both containing an essential prenyl moiety, are key electron carriers in respiratory energy generation. There is scant knowledge on the nature and regulation of bacterial isoprenoid pathways. In order to explore the cellular responses to perturbations in the mevalonate pathway, responsible for producing the isoprenoid precursor IPP in many Gram-positive bacteria and eukaryotes, we constructed three strains of Staphylococcus aureus in which each of the mevalonate pathway genes is regulated by an IPTG inducible promoter. We used DNA microarrays to profile the transcriptional effects of downregulating the components of the mevalonate pathway in S. aureus and demonstrate that decreased expression of the mevalonate pathway leads to widespread downregulation of primary metabolism genes, an upregulation in virulence factors and cell wall biosynthetic determinants, and surprisingly little compensatory expression in other isoprenoid biosynthetic genes. We subsequently correlate these transcriptional changes with downstream metabolic consequences. We used microarrays to profile the transcriptional changes incurred when downregulating mvaS, mvaA, or mvaK in S. aureus. Keywords: stress response S. aureus mutants were generated in which mvaS, mvaA, or mvaK were placed under control of the IPTG-inducible Pspac promoter. These mutants, as well as wildtype RN4220 S. aureus, were grown with or without 1 mM IPTG, harvested in exponential phase, and their total RNA was extracted and hybridized to Affymetrix GeneChips. Experiments were done in triplicate.
2010-05-05 | E-GEOD-13424 | biostudies-arrayexpress
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:Mevalonate pathway inhibition affects bladder cancer metastasis
| PRJNA1057080 | ENA
Project description:Metastasis is an important factor affecting the prognosis and survival of bladder cancer (BLCA) patients. Our previous study found that the mevalonate pathway is associated with the migratory ability of bladder cancer cells, but the exact mechanism is unclear. Here, we found that BLCA patients with mevalonate pathway activation had a poorer prognosis. Inhibition of the mevalonate pathway (simvastatin or zoledronic acid) resulted in a significant decrease in the migratory ability of BLCA cells. Therefore, we used proteomics to detect simvastatin- or zoledronic acid-treated BLCA cells to explore the effect of the mevalonate pathway on key proteins in BLCA cells.
2024-09-09 | PXD048067 |