96 research outputs found
MUC1-associated proliferation signature predicts outcomes in lung adenocarcinoma patients
Background: MUC1 protein is highly expressed in lung cancer. The cytoplasmic domain of MUC1 (MUC1-CD) induces tumorigenesis and resistance to DNA-damaging agents. We characterized MUC1-CD-induced transcriptional changes and examined their significance in lung cancer patients. Methods: Using DNA microarrays, we identified 254 genes that were differentially expressed in cell lines transformed by MUC1-CD compared to control cell lines. We then examined expression of these genes in 441 lung adenocarcinomas from a publicly available database. We employed statistical analyses independent of clinical outcomes, including hierarchical clustering, Student's t-tests and receiver operating characteristic (ROC) analysis, to select a seven-gene MUC1-associated proliferation signature (MAPS). We demonstrated the prognostic value of MAPS in this database using Kaplan-Meier survival analysis, log-rank tests and Cox models. The MAPS was further validated for prognostic significance in 84 lung adenocarcinoma patients from an independent database. Results: MAPS genes were found to be associated with proliferation and cell cycle regulation and included CCNB1, CDC2, CDC20, CDKN3, MAD2L1, PRC1 and RRM2. MAPS expressors (MAPS+) had inferior survival compared to non-expressors (MAPS-). In the initial data set, 5-year survival was 65% (MAPS-) vs. 45% (MAPS+, p < 0.0001). Similarly, in the validation data set, 5-year survival was 57% (MAPS-) vs. 28% (MAPS+, p = 0.005). Conclusions: The MAPS signature, comprised of MUC1-CD-dependent genes involved in the control of cell cycle and proliferation, is associated with poor outcomes in patients with adenocarcinoma of the lung. These data provide potential new prognostic biomarkers and treatment targets for lung adenocarcinoma
Gene Expression Profile Identifies Tyrosine Kinase c-Met as a Targetable Mediator of Antiangiogenic Therapy Resistance
PURPOSE: To identify mediators of glioblastoma anti-angiogenic therapy resistance and target these mediators in xenografts. EXPERIMENTAL DESIGN: We performed microarray analysis comparing bevacizumab-resistant glioblastomas (BRGs) to pre-treatment tumors from the same patients. We established novel xenograft models of anti-angiogenic therapy resistance to target candidate resistance mediator(s). RESULTS: BRG microarray analysis revealed upregulation versus pre-treatment of receptor tyrosine kinase c-Met, which underwent further investigation because of its prior biologic plausibility as a bevacizumab resistance mediator. BRGs exhibited increased hypoxia versus pre-treatment in a manner correlating with their c-Met upregulation, increased c-Met phosphorylation, and increased phosphorylation of c-Met-activated focal adhesion kinase (FAK) and STAT3. We developed two novel xenograft models of anti-angiogenic therapy resistance. In the first model, serial bevacizumab treatment of an initially responsive xenograft generated a xenograft with acquired bevacizumab resistance, which exhibited upregulated c-Met expression versus pre-treatment. In the second model, a BRG-derived xenograft maintained refractoriness to the MRI tumor vasculature alterations and survival-promoting effects of bevacizumab. Growth of this BRG-derived xenograft was inhibited by a c-Met inhibitor. Transducing these xenograft cells with c-Met shRNA inhibited their invasion and survival in hypoxia, disrupted their mesenchymal morphology, and converted them from bevacizumab-resistant to bevacizumab-responsive. Engineering bevacizumab-responsive cells to express constitutively active c-Met caused these cells to form bevacizumab-resistant xenografts. CONCLUSION: These findings support the role of c-Met in survival in hypoxia and invasion, features associated with anti-angiogenic therapy resistance; and growth and therapeutic resistance of xenografts resistant to anti-angiogenic therapy. Therapeutically targeting c-Met could prevent or overcome anti-angiogenic therapy resistance
Pancreatic cancer genomes reveal aberrations in axon guidance pathway genes.
Pancreatic cancer is a highly lethal malignancy with few effective therapies. We performed exome sequencing and copy number analysis to define genomic aberrations in a prospectively accrued clinical cohort (n = 142) of early (stage I and II) sporadic pancreatic ductal adenocarcinoma. Detailed analysis of 99 informative tumours identified substantial heterogeneity with 2,016 non-silent mutations and 1,628 copy-number variations. We define 16 significantly mutated genes, reaffirming known mutations (KRAS, TP53, CDKN2A, SMAD4, MLL3, TGFBR2, ARID1A and SF3B1), and uncover novel mutated genes including additional genes involved in chromatin modification (EPC1 and ARID2), DNA damage repair (ATM) and other mechanisms (ZIM2, MAP2K4, NALCN, SLC16A4 and MAGEA6). Integrative analysis with in vitro functional data and animal models provided supportive evidence for potential roles for these genetic aberrations in carcinogenesis. Pathway-based analysis of recurrently mutated genes recapitulated clustering in core signalling pathways in pancreatic ductal adenocarcinoma, and identified new mutated genes in each pathway. We also identified frequent and diverse somatic aberrations in genes described traditionally as embryonic regulators of axon guidance, particularly SLIT/ROBO signalling, which was also evident in murine Sleeping Beauty transposon-mediated somatic mutagenesis models of pancreatic cancer, providing further supportive evidence for the potential involvement of axon guidance genes in pancreatic carcinogenesis
Ischaemic conditioning and targeting reperfusion injury: a 30 year voyage of discovery
To commemorate the auspicious occasion of the 30th anniversary of IPC, leading pioneers in the field of cardioprotection gathered in Barcelona in May 2016 to review and discuss the history of IPC, its evolution to IPost and RIC, myocardial reperfusion injury as a therapeutic target, and future targets and strategies for cardioprotection. This article provides an overview of the major topics discussed at this special meeting and underscores the huge importance and impact, the discovery of IPC has made in the field of cardiovascular research
An Open Resource for Non-human Primate Imaging.
Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers that have the necessary facilities and capabilities. The PRIMatE Data Exchange (PRIME-DE) addresses this challenge by aggregating independently acquired non-human primate magnetic resonance imaging (MRI) datasets and openly sharing them via the International Neuroimaging Data-sharing Initiative (INDI). Here, we present the rationale, design, and procedures for the PRIME-DE consortium, as well as the initial release, consisting of 25 independent data collections aggregated across 22 sites (total = 217 non-human primates). We also outline the unique pitfalls and challenges that should be considered in the analysis of non-human primate MRI datasets, including providing automated quality assessment of the contributed datasets
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network
Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects
Thermal Conductivity of Hydrogen at High Pressure and High Temperature: Implications to Giant Planets
Abstract Hydrogen (H2) is the most abundant constituent in giant planets, but its thermal conductivity Î under extreme pressureâtemperature (PâT) conditions remains largely unknown. Here we report the Î of H2 from ambient to 60.2 GPa at 300 K and from 300 to 773 K at 2.1 GPa. At 300 K, the Î of liquid H2 fluctuates at âŒ0.7â1.1 W mâ1 Kâ1. Upon crystallization to H2âI phase, the Î jumps to 5.5 W mâ1 Kâ1 at 7.2 GPa, and monotonically increases with pressure to âŒ27 W mâ1 Kâ1 at 60.2 GPa. Upon heating, the Î of liquid H2 at 2.1 GPa scales with T0.68. Moreover, the density (Ï)âdependent compressional sound velocity (Vp) of liquid and solid H2 derived from Brillouin frequency data both follow the Birch's law. Besides the novel insights into the physics of thermal transport in H2 under extreme conditions, our results significantly advance the modeling of ÎâVpâÏ relationship in a planet with H2
Small Gauge Techniques for Removing a Fluocinolone Acetonide Implant
PurposeLong-acting injectable fluocinolone releasing implants are used in clinical practice. Although limited in scope, situations may arise where removal of the implant is warranted. We set out to describe possible explantation techniques and to determine whether these implants can be safely removed from a standard sclerotomy or eliminated using a vitrectomy system.MethodsA vitreoretinal surgery system was designed using a porcine eye model. A fluocinolone implant was injected into the vitreous cavity. Pars plana vitrectomy was performed and the vitreous cavity was infused with balanced salt solution. The injected implants were removed from 23-Gauge (G) and 25-Gauge (G) vitrectomy cannulas with 27-G forceps. The implants were examined under the microscope for induced defects. Implants were injected into the eye model and eliminated using a 23-G and 25-G vitrector system.ResultsThe implant was removed from both the 23-G and 25-G vitrectomy cannulas with only mild structural damage to the implant. During implant extraction through the 25-G sclerotomy, the cannula was dislodged from the incision along with the implant. The most technically challenging portion involved aligning the implant coaxially to allow for removal en bloc through the sclerotomy site. Implants could be eliminated using both the 23-G and 25-G vitrector using a low-cut rate.ConclusionThe fluocinolone implant was removed safely via standard 23-G or 25-G vitrectomy systems. It is unknown whether intraocular manipulation will affect pharmacokinetics of drug delivery if the implant is not explanted
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