170 research outputs found

    Glutathione conjugation of a cocaine pyrolysis product AEME and related compounds

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    Free-base ( crack ) cocaine smoking continues to be a popular method of drug abuse in the United States. Pyrolysis of free-base cocaine readily occurs, forming primarily benzoic acid and anhydroecgonine methyl ester (AEME), which structurally contains an alpha,beta-unsaturated carbonyl functional group. This electrophilic structure is suggestive of chemical reactivity with ubiquitously occurring cellular nucleophiles, such as glutathione. Glutathione adducts formed in vivo are metabolized to N-acetylcysteine derivatives by the enzymatically driven mercapturic acid pathway. AEME and its transesterification product in the presence of ethanol, anhydroecgonine ethyl ester (AEEE), were synthesized from cocaine hydrochloride. Glutathione (GSH) and mercapturic acid (NAC) conjugates of AEME were synthesized, and the stereochemistry of the AEME-NAC conjugate was structurally elucidated by NMR and mass spectrometry. Using Ellman\u27s method to monitor glutathione depletion over time, AEME reacted with GSH at a slower rate (6.8 x 10 -3 mM-1min-1) than equimolar concentrations of arecoline or ethacrynic acid (2.2 x 10-1 mM-1min -1 and 4.1 x 10-1 mM-1min-1, respectively). AEME also reduced the chemical formation of the DCNB-SG conjugate. In pooled human liver cytosol, the incubation of AEME with GSH at 37°C for 60 minutes at different pH levels was analyzed by LC-MS. We found unequivocal data suggesting enzymatic catalysis of AEME to AEME-SG in the presence of reduced GSH. However, AEME (10 mM) significantly reduced GST activity (p \u3c 0.005) following a 20 hour incubation with HLC (1 mg). Additionally, AEME exhibited mixed-linear inhibition (Ki = 334 muM) towards cytosolic GST activity. A solid phase extraction (SPE) method was developed to extract cocaine and cocaine metabolites from urine. We identified approximately 50 ng/mL of AEEE by LC-MS in the urine of a known freebase cocaine/ethanol abuser, and additionally confirmed the structure of the metabolite by LC-MS/MS. This SPE method is useful in detecting AEME conjugates in biological fluids. We studied the cytotoxicity of pyrolysis products on A549 lung fibroblasts using trypan blue exclusion and flow cytometry. To summarize, our work suggests that AEME plays a potential role in the sequelae of abused cocaine related toxicities

    Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context

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    Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts

    Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas

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    Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN

    Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas

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    This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin

    Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images

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    Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL maps are derived through computational staining using a convolutional neural network trained to classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and correlation with overall survival. TIL map structural patterns were grouped using standard histopathological parameters. These patterns are enriched in particular T cell subpopulations derived from molecular measures. TIL densities and spatial structure were differentially enriched among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for the TCGA image archives with insights into the tumor-immune microenvironment

    The Association of Cell Cycle Checkpoint 2 Variants and Kidney Function: Findings of the Family Blood Pressure Program and the Atherosclerosis Risk in Communities Study

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    Recent experimental evidence suggests that DNA damage and cell cycle regulatory proteins are involved in kidney injury and apoptosis. The checkpoint 2 gene (CHEK2) is an important transducer in DNA damage signaling pathways in response to injury, and therefore, CHEK2 variants may affect susceptibility to kidney disease

    The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

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    This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys

    The 16th Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra

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    This paper documents the 16th data release (DR16) from the Sloan Digital Sky Surveys (SDSS), the fourth and penultimate from the fourth phase (SDSS-IV). This is the first release of data from the Southern Hemisphere survey of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2); new data from APOGEE-2 North are also included. DR16 is also notable as the final data release for the main cosmological program of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), and all raw and reduced spectra from that project are released here. DR16 also includes all the data from the Time Domain Spectroscopic Survey and new data from the SPectroscopic IDentification of ERosita Survey programs, both of which were co-observed on eBOSS plates. DR16 has no new data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey (or the MaNGA Stellar Library "MaStar"). We also preview future SDSS-V operations (due to start in 2020), and summarize plans for the final SDSS-IV data release (DR17)

    The Cancer Genome Atlas Comprehensive Molecular Characterization of Renal Cell Carcinoma

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