Project description:To determine microRNA expression in chemoresistant ovarian cancer, we have employed whole microRNA microarray expression profiling as a discovery platform to identify genes with the potential to distinguish recurrent ovarian cancer. 8 recurrent ovarian cancer tissue and 8 primary ovarian cancer tissue and 4 normal ovarian tissue was used to identify miRNA profiling.

2017-06-01 | GSE83693 | GEO

Whole genome characterisation of chemoresistant ovarian cancer [NanoString miRNA]

Project description:Patients with high-grade serous ovarian cancer (HGSC) have experienced little improvement in overall survival, and standard treatment has not advanced beyond platinum-based combination chemotherapy, during the past 30 years. To understand the drivers of clinical phenotypes better, here we use whole-genome sequencing of tumour and germline DNA samples from 92 patients with primary refractory, resistant, sensitive and matched acquired resistant disease. We show that gene breakage commonly inactivates the tumour suppressors RB1, NF1, RAD51B and PTEN in HGSC, and contributes to acquired chemotherapy resistance. CCNE1 amplification was common in primary resistant and refractory disease. We observed several molecular events associated with acquired resistance, including multiple independent reversions of germline BRCA1 or BRCA2 mutations in individual patients, loss of BRCA1 promoter methylation, an alteration in molecular subtype, and recurrent promoter fusion associated with overexpression of the drug efflux pump MDR1. Total RNA was hybridised to NanoString miRNA Human v2.1 probes, immobilized to NanoString cartridge and analysed on the NanoString Digital Analyzer. NanoString nSolver Analysis Software was utilised to check QC metrics and extract raw miRNA counts. Expression was normalised for input using the housekeeping genes. Contributor: The Australian Ovarian Cancer Study Group

2015-05-19 | E-GEOD-65819 | biostudies-arrayexpress

Homo sapiens

Project description:Characterizing the Chemoresistant Ovarian Cancer Population using the Heterogeneous PDX

| PRJNA252939 | ENA

Homo sapiens foetal mesenchymal stem cell miRNA transcriptome

Project description:We have sequenced miRNA libraries from human embryonic, neural and foetal mesenchymal stem cells. We report that the majority of miRNA genes encode mature isomers that vary in size by one or more bases at the 3’ and/or 5’ end of the miRNA. Northern blotting for individual miRNAs showed that the proportions of isomiRs expressed by a single miRNA gene often differ between cell and tissue types. IsomiRs were readily co-immunoprecipitated with Argonaute proteins in vivo and were active in luciferase assays, indicating that they are functional. Bioinformatics analysis predicts substantial differences in targeting between miRNAs with minor 5’ differences and in support of this we report that a 5’ isomiR-9-1 gained the ability to inhibit the expression of DNMT3B and NCAM2 but lost the ability to inhibit CDH1 in vitro. This result was confirmed by the use of isomiR-specific sponges. Our analysis of the miRGator database indicates that a small percentage of human miRNA genes express isomiRs as the dominant transcript in certain cell types and analysis of miRBase shows that 5’ isomiRs have replaced canonical miRNAs many times during evolution. This strongly indicates that isomiRs are of functional importance and have contributed to the evolution of miRNA genes

2014-08-06 | GSE58734 | GEO

Crystal structure of Homo sapiens kynureninase.

Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.

| S-EPMC2531291 | biostudies-literature

Homo sapiens foetal mesenchymal stem cell miRNA transcriptome

2014-08-06 | E-GEOD-58734 | biostudies-arrayexpress

Homo sapiens whole blood.

Project description:RNA extracted at 240min. Samples are rRNA depleted. Expression measurement of Homo sapiens genes.

2019-07-31 | GSE114179 | GEO