Selenium Chemoprevention: Benefits and Harms
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PROVIDER: PRJNA673534 | ENA |
REPOSITORIES: ENA
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Project description:Selenium Chemoprevention: Benefits and Harms
| PRJNA673535 | ENA
Project description:RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent the development or recurrence of cancer. Selenium may be effective in preventing the recurrence of adenomatous colorectal polyps.
PURPOSE: This randomized phase III trial is studying selenium to see how well it works in preventing the recurrence of polyps in patients with adenomatous colorectal polyps.
| 2010525 | ecrin-mdr-crc
Project description:In parallel with the inconsistency in observational studies and chemoprevention trials, the molecular mechanisms by which selenium may affect prostate cancer risk have not been elucidated. We conducted a randomized, placebo-controlled intervention trial to examine the effects of a short-term intervention with selenized yeast on whole-genome expression profiles in non-malignant prostate tissue. Twenty-three men receiving prostate biopsies were randomly assigned to take 300 µg selenized yeast per day (n=12) or placebo (non-selenized yeast, n=11) during a median intervention period of 35 (interquartile range: 31-35) days. Prostate specimens, collected from the transition zone before and after intervention, of 15 participants (n=8 selenium, n=7 placebo) were available for analysis using Affymetrix GeneChip Human 1.0 ST Arrays. Pathway and gene set enrichment analyses revealed that the intervention with selenium resulted in a down-regulated expression of genes involved in signaling pathways related to cellular adhesion, migration, invasion, remodeling and immune responses. Specifically, expression of the well-established epithelial marker E-cadherin was up-regulated, while mesenchymal markers, such as vimentin and fibronectin, were down-regulated after the intervention with selenium. This implies an effect of selenium on the epithelial-to-mesenchymal transition (EMT). Moreover, selenium affected expression of genes involved in wound healing and inflammation, processes which are both related to EMT. In conclusion, our data showed that selenium affected expression of genes implicated in EMT, mainly represented by a change in the direction of the epithelial rather than the mesenchymal phenotype.
2017-01-19 | GSE77959 | GEO
Project description:Methanococcus maripaludis utilizes selenocysteine-(Sec-) containing proteins (selenoproteins), mostly active in the organism’s primary energy metabolism, methanogenesis. Under selenium depletion, M. maripaludis employs a set of enzymes containing cysteine (Cys) instead of Sec. The genes coding for these Sec-/Cys-containing isoforms are the only genes known expression of which is influenced by the selenium status of the cell. Using quantitative proteomics and transcriptomics approx. 7% and 12%, respectively, of all genes/proteins were differentially expressed/synthesized in response to the selenium supply. Some of the genes identified involve methanogenesis, nitrogenase functions, and putative transporters. An increase of transcript abundance for putative transporters under selenium-depleted conditions indicated the organism’s effort to tap into alternative sources of selenium. Selenium sources M. maripaludis is known to utilize are selenite and dimethylselenide. To expand this list, a selenium responsive reporter strain was assessed with nine other, environmentally relevant selenium species. While some had a similar biological window as selenite, others were effectively utilized at lower concentrations. Conversely, selenate and seleno-amino acids were only utilized at unphysiologically high concentrations and two compounds were not utilized at all. To address the role of the selenium-regulated putative transporters in selenium transport, M. maripaludis mutant strains lacking one or two of the putative transporters were tested for the capability to utilize the different selenium species. Of the five putative transporters analyzed by loss-of-function mutagenesis, none appeared to be absolutely required for utilizing any of the selenium species tested, indicating they have redundant and/or overlapping specificities, or are not dedicated selenium transporters.
2024-03-27 | PXD047095 | Pride
Project description:We studied the application of transcriptome technology in alfalfa selenium treatment. After spraying sodium selenite on the leaves, the process of selenium absorption and assimilation of alfalfa is unknown. The time point of transcriptome determination was determined by measuring the change of selenium content. Our results showed that 12 h was the key point of the change of selenium content in alfalfa, that is, the selenium content increased continuously before 12 h, decreased gradually after 12 h, and remained stable after 48 h. Transcriptome sequencing showed that phosphorus transporter and endocytosis related genes may be involved in selenium absorption at 12 h compared with 0 H. 12-48 h, some thiometabolic pathways may be involved in selenium metabolism and ubiquitination pathway, which may be the detoxification pathway of selenoprotein.
2024-10-27 | GSE186868 | GEO
Project description:Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-κB targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-κB signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
2018-07-13 | GSE117026 | GEO
Project description:Genome-wide expression analysis in C. Elegans grown in axenic media with low to toxic selenium concentrations We performed Affymetrix micorarray-based transcriptional profiling on wild-type C. Elegans Bristol N2 grown in low Se axenic media supplemented with five concentrations of selenium, from low to toxic, and harvested at the L4-larva stage.
2014-07-03 | GSE54011 | GEO
Project description:New Zealand (NZ) has high bowel cancer rates, which the Bowel Screening Programme aims to reduce by early detection of bowel cancer and its precursor, adenomas (polyps). Bowel cancer and adenoma rates are higher in countries like NZ with low intake of the essential trace mineral selenium. Overseas, trials of selenium supplements reduced adenoma recurrence in people with low blood selenium, but not with high levels (where adding selenium increased health risks). Laboratory research explained this, and found certain types of selenium are safer and more effective. The optimal type and dose of selenium to use in NZ cancer prevention trials is not known.
The main objective of this trial is to evaluate which dose and type of selenium (either selenomethionine or methylselenocysteine) gives optimal selenium status to maximise cancer prevention without causing health problems from excessive selenium intake. We also want to see how much selenium is needed according to selenium blood levels before starting selenium in the trial. Side effects will be evaluated, as will recruitment rates.
This will determine the feasibility of developing a large randomised trial of selenium to reduce the recurrence rates for advanced adenomas in NZ.
This trial will recruit 60 patients from Middlemore and Waikato Hospitals with an advanced adenoma removed through the Bowel Screening Programme. Patients will take one selenium compound, dosed at 50 mcg/day for 6 weeks then 100 mcg/day for 6 weeks, and will have blood tests at baseline, then blood tests and evaluation of side effects at 6 weeks and 12 weeks.
| 2382551 | ecrin-mdr-crc
Project description:The synthesis mechanisms and function evaluation of selenium(Se)-enriched microorganism remain relatively unexplored. We here report the Se biotransformation by A. oryzae A02. Comparative RNA-Seq analysis revealed the upregulation of functional genes implicated in selenium transformation, activating multiple potential pathways for selenium reduction. The assimilatory and dissimilatory reductions of Se oxyanions engaged numerous parallel and interconnected pathways, manifesting a harmonious equilibrium in overall Se biotransformation in A. oryzae A02.
2024-07-07 | GSE270867 | GEO