Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA171389 | ENA |
REPOSITORIES: ENA
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Project description:Sirtuins (SIRT) are NAD-dependent protein deacteylases and function in cellular metabolism, stress resistance, proliferation and disease. For SIRT7, a role in ribosomal gene transcription is proposed, but its function in cancer is currently unknown. In this study, we showed that SIRT7 expression was up-regulated in a large cohort of human hepatocellular carcinoma (HCC) patients, and that high expression of SIRT7 was associated with poor prognosis of HCC patients. Notably, inactivation of SIRT7 by siRNA suppressed tumor cell growth and caused G1/S cell cycle arrest in liver cancer cells. This treatment restored p21WAF1/Cip1 activity, induced Beclin-1 and autophagic gene expression and repressed cyclin D1. To explore mechanisms in SIRT7 regulation, microRNA (miRNA) profiling was carried out. This identified five significantly down-regulated miRNAs in HCC. Bioinformatic analysis of target sites and ectopic expression in HCC cells evidenced miR-125a-5p and miR-125b to suppress SIRT7 and cyclin D1 expression and to induce p21WAF1/Cip1-dependent G1 cell cycle arrest. Furthermore, treatment of HCC cells with 5-aza-2’-deoxycytidine or ectopic expression of wild-type but not mutated p53 restored miR-125a-5p and miR-125b expression and inhibited tumor cell growth to suggest their regulation by promoter methylation and p53 activity. To evidence clinical significance of these findings, mutations in the DNA binding domain of p53 and promoter methylation of miR-125b were investigated. Four out of nine patients with induced SIRT7 carried mutations in p53 gene and one patient showed hypermethylation of miR-125b promoter region. Conclusion: Our findings suggest that oncogenic potential of SIRT in hepatocarcinogenesis and that a regulatory loop is proposed whereby SIRT7 inhibits transcriptional activation of p21WAF1/Cip1 via repression of miR-125a-5p and miR-125b. This makes SIRT7 a promising target in cancer therapy.
2012-09-30 | GSE39678 | GEO
Project description:Rationale: Currently, there are no blood-based biomarkers with clinical utility for acute ischemic stroke (IS). microRNAs (miRNAs) show promise as disease markers due to their cell-type specific expression patterns and stability in peripheral blood. Objective: To identify circulating miRNAs associated with acute IS, determine their temporal course up to 90 days post-stroke, and explore their utility as an early diagnostic marker. Methods and Results: We used RNA sequencing to study expression changes of circulating miRNAs in a discovery sample of 20 IS patients and 20 matched healthy control subjects (HCs). We further applied qRT-PCR in independent samples for validation (40 IS patients and 40 matched controls), replication (200 IS patients, 100 HCs), and in 72 patients with transient ischemic attacks (TIA). Sampling of patient plasma was done immediately upon hospital arrival. We identified, validated, and replicated three differentially expressed miRNAs, which were upregulated in IS patients compared to both HCs (miR-125a-5p [1.8-fold; P=1.5x10-6], miR-125b-5p [2.5-fold; P=5.6x10-6], and miR-143-3p [4.8-fold; P=7.8x10-9]) and TIA patients (miR-125a-5p: P=0.003, miR-125b-5p: P=0.003, miR-143-3p: P=0.005). Longitudinal analysis of expression levels up to 90 days after stroke revealed a normalization to control levels for miR-125b-5p and miR-143-3p starting at day two, while miR-125a-5p remained elevated. Levels of all three miRNAs depended on platelet numbers in a platelet spike-in experiment, but were unaffected by chemical hypoxia in N2a cells and in experimental stroke models. In a random forest classification, miR-125a-5p, miR-125b-5p and miR-143-3p differentiated between HCs and IS patients with an area under the curve (AUC) of 0.90 (sensitivity: 85.6%; specificity: 76.3%), which was superior to multimodal cranial computed tomography obtained for routine diagnostics (sensitivity: 72.5%) and previously reported biomarkers of acute IS (neuron specific enolase: AUC=0.69, interleukin 6: AUC=0.82). Conclusions: A set of circulating miRNAs (miR-125a-5p, miR-125b-5p, miR-143-3p) associates with acute IS and might have clinical utility as an early diagnostic marker.
2018-02-22 | GSE110993 | GEO
Project description:RNA-seq identifies circulating miR-125a-5p, miR-125b-5p and miR-143-3p as potential biomarkers for acute ischemic stroke
| PRJNA435535 | ENA
Project description:miR-125b-5p is a well known miRNA already describded in several forms of cancer. miR-125b-5p is expressed in adipose tissue, adipocytes as well as their precursor cells. We aim to invest the role of miR-125b-5p in white adipocytes conversion into brite adipocytes. To get an idea about putative targets of miR-125b-5p in adipocyte conversion, we transfected miR-125b-5p mimic in human Multipotent Adipose-Derived Stem (hMADS) cells, differenciated in white adipocytes. Gene expression profiling is performed 48h after hMADSC transfection. Two-condition experiment, hMADS cells at day 16 after conversion of white adipocytes into brite adipocytes, comparison of cells transfected with a mimic miR-125b-5p to cells transfected with a negative controle. Biological replicates: 4, indepently grown and harvested. On each array, one biological replicate of mimic miR-125b-5p transfected cells was directly compared to one biological replicate of mimic negative control transfected cells (serving as reference sample). All hybridizations were repeated with reversed dye assignment (dye-swap) as technical replicates.
2016-07-01 | E-GEOD-80816 | biostudies-arrayexpress
Project description:miR-125b-5p is a well known miRNA already describded in several forms of cancer. miR-125b-5p is expressed in adipose tissue, adipocytes as well as their precursor cells. We aim to invest the role of miR-125b-5p in white adipocytes conversion into brite adipocytes. To get an idea about putative targets of miR-125b-5p in adipocyte conversion, we transfected miR-125b-5p mimic in human Multipotent Adipose-Derived Stem (hMADS) cells, differenciated in white adipocytes. Gene expression profiling is performed 48h after hMADSC transfection.
2016-07-01 | GSE80816 | GEO
Project description:SIRT7 is a member of the mammalian sirtuin family of NAD+ dependent deacylases, and interacts with RNA polymerase I and UBF to regulate rDNA transcription. Various studies in mammalian cells and human clinical data have linked SIRT7 to cancer. However studies differ as to whether SIRT7 is oncogenic or tumor suppressive. Here we analyzed SIRT7 knockout mice and found SIRT7 deficiency caused sub-Mendelian birth numbers and a reduction in body size. Moreover, at 18 month of age, roughly 60 % of the SIRT7 knockout mice develop hepatocellular carcinoma (HCC), in many cases leading to suspected metastasis. Several HCC associated genes were up-regulated in livers of mice as young as 6 months of age, particularly targets of the proto-oncogene, c- MYC. Indeed SIRT7 interacts with MYC at endogenous protein levels and also represses MYC activity. Our findings thus show that SIRT7 acts as a tumor suppressor in vivo, and may suggest novel strategies to treat liver cancer. The mRNAs from 3 replicates of mouse Wildtype liver compared to 3 replicates of mouse liver lacking SIRT7
2014-08-20 | E-GEOD-50076 | biostudies-arrayexpress
Project description:Aims/hypothesis. Ectopic calcification is a typical feature of diabetic vascular disease and resembles an accelerated aging phenotype. We previously found an excess of myeloid calcifying cells (MCCs) in diabetic patients. We herein examined molecular and cellular pathways linking atherosclerotic calcification with calcification by myeloid cells in the diabetic milieu. Methods. We first examined the associations among coronary calcification, MCC levels, and mononuclear cell gene expression in a cross-sectional study of 87 type 2 diabetic patients undergoing elective coronary angiography. Then, we undertook in vitro studies on mesenchymal stem cells (MSCs) and on the THP-1 myeloid cells line to verify the causal relationships of the observed associations. Results. Coronary calcification was associated with 2.8-times higher MCC levels (p=0.037) and 50% elevated expression of the osteogenic gene RUNX2 in mononuclear cells, whereas expression of Sirtuin-7 (SIRT7) was inversely correlated with calcification. In standard differentiation assays of MSCs, SIRT7 knockdown activated the osteogenic program and worsened calcification, especially in the presence of high (20 mM) glucose. In the monocytic cell line THP-1, SIRT7 downregulation drove a pro-calcific phenotype, whereas SIRT7 overexpression prevented high-glucose induced calcification. Through the JAK/STAT pathway, high glucose induced miR-125b-5p, which in turn targeted SIRT7 in myeloid cells and was directly associated with coronary calcification. Conclusions/interpretation. We describe a new pathway elicited by high glucose trough the JAK/STAT cascade, involving regulation of SIRT7 by mir-125b-5p driving calcification by myeloid cells. This pathway is associated with coronary calcification in diabetic patients and may be a target to tackle diabetic vascular disease.
2022-01-15 | GSE193510 | GEO
Project description:Breast Cancer is the cancer with most incidence and mortality in women. microRNAs are emerging as novel prognosis/diagnostic tools. Our aim was to identify a serum microRNA signature useful to predict cancer development. We focused on studying the expression levels of 30 microRNAs in the serum of 96 breast cancer patients versus 92 control individuals. Bioinformatic studies provide a microRNA signature, designated as a predictor, based upon the expression levels of 5 microRNAs. Then, we tested the predictor in a group of 60 randomly chosen women. Lastly, a proteomic study unveiled the over-expression and down-regulation of proteins differently expressed in the serum of breast cancer patients versus that of control individuals. Twenty-six microRNAs differentiate cancer tissue from healthy tissue and 16 microRNAs differentiate the serum of cancer patients from that of the control group. The tissue expression of miR-99a-5p, mir-497-5p, miR-362, and miR-1274, and the serum levels of miR-141 correlated with patient survival. Moreover, the predictor consisting of mir-125b-5p, miR-29c-3p, mir-16-5p, miR-1260, and miR-451a was able to differentiate breast cancer patients from controls. The predictor was validated in 20 new cases of breast cancer patients and tested in 60 volunteer women, assigning 11 out of 60 women to the cancer group. An association of low levels of mir-16-5p with a high content of CD44 protein in serum was found. Circulating microRNAs in serum can represent biomarkers for cancer prediction. Their clinical relevance and use of the predictor here described might be of potential importance for breast cancer prediction.
2020-09-18 | PXD020795 | Pride
Project description:Background/Objective: Quantitative real-time PCR (RT-qPCR) is widely used in miRNA expression studies on cancer. To compensate for the analytical variability produced by the multiple steps of the method, relative quantification of the measured miRNAs is required, which is based on normalization to endogenous reference genes. A literature search in PubMed revealed that no study has been performed so far on reference miRNAs for normalization of miRNA expression in urothelial carcinoma. The aim of this study was to identify suitable reference genes for miRNA expression studies by RT-qPCR in urothelial carcinoma. Methods: Candidate reference miRNAs were selected from 24 papillary urothelial carcinoma and normal bladder tissue samples by miRNA microarrays. The usefulness of these candidate reference miRNAs together with the commonly for normalization purposes used small nuclear RNAs RNU6B, RNU48, and Z30 were thereafter validated by RT-qPCR in 58 tissue samples and analyzed by the algorithms geNorm, NormFinder, and BestKeeper. Principal Findings: Based on the miRNA microarray data, a total of 16 miRNAs were identified as putative reference genes. After validation by RT-qPCR, miR-101, miR-125a-5p, miR-148b, miR-151-3p, miR-151-5p, miR-181a, miR-181b miR-29c, miR-324-3p, miR-424, miR-874, RNU6B, RNU48, and Z30 were used for geNorm, NormFinder, and BestKeeper analyses that gave different combinations of recommended reference genes for normalization. Conclusions: The present study provided the first systematic analysis for identifying suitable reference miRNAs for miRNA expression studies of urothelial carcinoma by RT-qPCR. Different combinations of reference genes resulted in reliable expression data for both strongly and less strongly altered miRNAs. Notably, RNU6B, which is the most frequently used reference gene for miRNA studies, gave inaccurate normalization. The combination of four (miR-125a-5p, miR-148b, miR-151-3p, and miR-151-5p) or three (miR-148b, miR-874, miR-181b) miRNA reference genes is recommended for normalization. Candidate reference miRNAs (for RT-qPCR analysis) were selected from 24 papillary urothelial carcinoma and normal bladder tissue samples by miRNA microarrays.
2013-02-26 | E-GEOD-36121 | biostudies-arrayexpress
Project description:SIRT7 is a member of the mammalian sirtuin family of NAD+ dependent deacylases, and interacts with RNA polymerase I and UBF to regulate rDNA transcription. Various studies in mammalian cells and human clinical data have linked SIRT7 to cancer. However studies differ as to whether SIRT7 is oncogenic or tumor suppressive. Here we analyzed SIRT7 knockout mice and found SIRT7 deficiency caused sub-Mendelian birth numbers and a reduction in body size. Moreover, at 18 month of age, roughly 60 % of the SIRT7 knockout mice develop hepatocellular carcinoma (HCC), in many cases leading to suspected metastasis. Several HCC associated genes were up-regulated in livers of mice as young as 6 months of age, particularly targets of the proto-oncogene, c- MYC. Indeed SIRT7 interacts with MYC at endogenous protein levels and also represses MYC activity. Our findings thus show that SIRT7 acts as a tumor suppressor in vivo, and may suggest novel strategies to treat liver cancer.
2014-08-20 | GSE50076 | GEO