Project description:Nasopharyngeal carcinoma (NPC) is a challenging cancer that is rare in the United States but shows exceptionally high incidence in Southern China, Indonesia, and Malaysia. While the hallmark of NPC is striking geographic variation, early detection and clinical management are also critical characteristics of this cancer. The etiology of NPC is complex, involving the interplay of multiple factors, including Epstein Barr Virus (EBV), which appears to play an oncogenic role. While multimodality therapy is the mainstay of treatment for NPC, the impact of this treatment is greatly influenced by the presenting tumor stage, tumor size, nodal involvement, and the histologic subtype classification. Up to 40% percent of NPC cases present at an advanced stage, likely due to its deep location in the lymphatic-rich nasopharynx and its propensity for early lymphatic spread. Recent modifications in the TNM staging schema have attempted to improve prognostic accuracy, but variations in clinical outcome are still reported in patients with the same stage and similar treatment regimens. The various molecular markers developed to monitor disease progression have also proven unreliable. Hence, there is a significant need for a new kind of prognostic biomarker for NPC. Herein different approaches were applied to a set of samples to detect NPC-related miRNAs, potential circulating biomarkers. We have optimized the extraction of total RNA from NPC Formalin-fixed, paraffin-embedded (FFPE) samples and sera from four patients and matched controls and analyzed the miRNA expression profile by microarray, qPCR and RNAseq. The microarray analysis showed that 46 miRNAs were found to be differentially and significantly expressed in carcinogenic tissue compared to healthy tissue. Twenty-three (23) microRNAs were significantly upregulated (21 human microRNAs and 2 EBV miRNAs), whereas 13 were down-regulated.
Project description:Nasopharyngeal carcinoma (NPC) is a challenging cancer that is rare in the United States but shows exceptionally high incidence in Southern China, Indonesia, and Malaysia. While the hallmark of NPC is striking geographic variation, early detection and clinical management are also critical characteristics of this cancer. The etiology of NPC is complex, involving the interplay of multiple factors, including Epstein Barr Virus (EBV), which appears to play an oncogenic role. While multimodality therapy is the mainstay of treatment for NPC, the impact of this treatment is greatly influenced by the presenting tumor stage, tumor size, nodal involvement, and the histologic subtype classification. Up to 40% percent of NPC cases present at an advanced stage, likely due to its deep location in the lymphatic-rich nasopharynx and its propensity for early lymphatic spread. Recent modifications in the TNM staging schema have attempted to improve prognostic accuracy, but variations in clinical outcome are still reported in patients with the same stage and similar treatment regimens. The various molecular markers developed to monitor disease progression have also proven unreliable. Hence, there is a significant need for a new kind of prognostic biomarker for NPC. Herein different approaches were applied to a set of samples to detect NPC-related miRNAs, potential circulating biomarkers. We have optimized the extraction of total RNA from NPC Formalin-fixed, paraffin-embedded (FFPE) samples and sera from four patients and matched controls and analyzed the miRNA expression profile by microarray, qPCR and RNAseq. The microarray analysis showed that 46 miRNAs were found to be differentially and significantly expressed in carcinogenic tissue compared to healthy tissue. Twenty-three (23) microRNAs were significantly upregulated (21 human microRNAs and 2 EBV miRNAs), whereas 13 were down-regulated. A total of 8 unique samples were analyzed on Agilent human miRNA microarray (miRBase Release 16.0). Of the 8 samples, 4 are from Non-keratinizing NPC tissue. Non-NPC (normal) tissue were taken from 4 individuals that were diagnosed with NPC (2 of which were matched/paired from the NPC case).
Project description:MicroRNAs are useful biomarkers for various disease states, and their preservation in formalin-fixed, paraffin-embedded (FFPE) tissue makes them particularly useful for clinicogenetic studies. Although global microRNA expression in FFPE samples is routinely measured with microarrays, the utility of RNA sequencing for such profiling has yet to be established. In this study, to appraise the suitability of RNA sequencing, microRNAs in RNA from pathologic stage I lung adenocarcinoma FFPE samples were quantified with 8x60K Agilent® SurePrint™ G3 Human miRNA 8x60k (release 16.0) microarray and Illumina® HiSeq™ 2000 sequencing platforms.
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
Project description:MicroRNAs regulate several aspects of tumorigenesis and cancer progression. Most cancer tissues are archived formalin-fixed and paraffin-embedded (FFPE). While microRNAs are a more stable form of RNA thought to withstand FFPE-processing and degradation there is only limited evidence for the latter assumption. We examined whether microRNA profiling can be successfully conducted on FFPE cancer tissues using SOLiD ligation based sequencing. Tissue storage times (3-9 years) appeared to not affect the number of detected microRNAs in FFPE samples compared to matched frozen samples (paired t-test p>0.7). Correlations of microRNA expression values were very high across microRNAs in a given sample (Pearson’s r=0.71-0.95). Higher variance of expression values among samples was associated with higher correlation coefficients between FFPE and frozen tissues. One of the FFPE samples in this study was degraded for unknown reasons with a peak read length of 17 nucleotides compared to 21 in all other samples. The number of detected microRNAs in this sample was within the range of microRNAs detected in all other samples. Ligation-based microRNA deep sequencing on FFPE cancer tissues is feasible and RNA degradation to the degree observed in our study appears to not affect the number of microRNAs that can be quantified.
Project description:ATAC-seq samples from 2 species and 2 cell types were generated to study cis-regulatory element evolution. Briefly, previously generated urinary stem cell derived iPS-cells (Homo sapiens) of 2 human individuals and fibroblast derived cynomolgus macaque iPSCs (Macaca fascicularis) of 2 individuals (Geuder et al. 2021) were differentiated to neural progenitor cells via dual-SMAD inhibition as three-dimensional aggregation culture (Chambers et al. 2009; Ohnuki et al. 2014). The NPC lines were cultured in NPC proliferation medium and passaged 2 - 4 times until they were dissociated and subjected to ATAC-seq together with the respective iPSC clones. ATAC-seq libraries were generated using the Omni-ATAC protocol (Corces et al. 2017) with minor modifications.
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.