Publications by authors named "J Barry Maynard"

638 Publications

Methods for Enrichment and Assignment of N-Acetylglucosamine Modification Sites.

Mol Cell Proteomics 2021 Feb 9;20:100031. Epub 2021 Feb 9.

Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA. Electronic address:

O-GlcNAcylation, the addition of a single N-acetylglucosamine residue to serine and threonine residues of cytoplasmic, nuclear, or mitochondrial proteins, is a widespread regulatory posttranslational modification. It is involved in the response to nutritional status and stress, and its dysregulation is associated with diseases ranging from Alzheimer's to diabetes. Although the modification was first detected over 35 years ago, research into the function of O-GlcNAcylation has accelerated dramatically in the last 10 years owing to the development of new enrichment and mass spectrometry techniques that facilitate its analysis. This article summarizes methods for O-GlcNAc enrichment, key mass spectrometry instrumentation advancements, particularly those that allow modification site localization, and software tools that allow analysis of data from O-GlcNAc-modified peptides.
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http://dx.doi.org/10.1074/mcp.R120.002206DOI Listing
February 2021

Bioproduced Proteins On Demand (Bio-POD) in hydrogels using .

Bioact Mater 2021 Aug 27;6(8):2390-2399. Epub 2021 Jan 27.

Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.

Traditional production of industrial and therapeutic proteins by eukaryotic cells typically requires large-scale fermentation capacity. As a result, these systems are not easily portable or reusable for on-demand protein production applications. In this study, we employ Bioproduced Proteins On Demand (Bio-POD), a F127-bisurethane methacrylate hydrogel-based technique that immobilizes engineered for preservable, on-demand production and secretion of medium- and high-molecular weight proteins (in this case, SEAP, α-amylase, and anti-HER2). The gel samples containing encapsulated-yeast demonstrated sustained protein production and exhibited productivity immediately after lyophilization and rehydration. The hydrogel platform described here is the first hydrogel immobilization using a system to produce recombinant proteins of this breadth. These results highlight the potential of this formulation to establish a cost-effective bioprocessing strategy for on-demand protein production.
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http://dx.doi.org/10.1016/j.bioactmat.2021.01.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7846901PMC
August 2021

Regional and Volumetric Parameters for Diffusion-Weighted WHO Grade II and III Glioma Genotyping: A Method Comparison.

AJNR Am J Neuroradiol 2021 03 7;42(3):441-447. Epub 2021 Jan 7.

From the Neuroradiological Academic Unit (S.C.T., J.A.M, S.J.W., L.M., H.R.J.), Department of Brain, Repair and Rehabilitation, UCL Institute of Neurology, London, UK.

Background And Purpose: Studies consistently report lower ADC values in () wild-type gliomas than in mutant tumors, but their methods and thresholds vary. This research aimed to compare volumetric and regional ADC measurement techniques for glioma genotyping, with a focus on status prediction.

Materials And Methods: Treatment-naïve World Health Organization grade II and III gliomas were analyzed by 3 neuroradiologist readers blinded to tissue results. ADC minimum and mean ROIs were defined in tumor and in normal-appearing white matter to calculate normalized values. T2-weighted tumor VOIs were registered to ADC maps with histogram parameters (mean, 2nd and 5th percentiles) extracted. Nonparametric testing (eta and ANOVA) was performed to identify associations between ADC metrics and glioma genotypes. Logistic regression was used to probe the ability of VOI and ROI metrics to predict status.

Results: The study included 283 patients with 79 wild-type and 204 mutant gliomas. Across the study population, status was most accurately predicted by ROI mean normalized ADC and VOI mean normalized ADC, with areas under the curve of 0.83 and 0.82, respectively The results for ROI-based genotyping of nonenhancing and solid-patchy enhancing gliomas were comparable with volumetric parameters (area under the curve = 0.81-0.84). In rim-enhancing, centrally necrotic tumors ( = 23), only volumetric measurements were predictive (0.90).

Conclusions: Regional normalized mean ADC measurements are noninferior to volumetric segmentation for defining solid glioma status. Partially necrotic, rim-enhancing tumors are unsuitable for ROI assessment and may benefit from volumetric ADC quantification.
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http://dx.doi.org/10.3174/ajnr.A6965DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959449PMC
March 2021

Differential mast cell phenotypes in benign versus cancer tissues and prostate cancer oncologic outcomes.

J Pathol 2021 Apr 26;253(4):415-426. Epub 2021 Jan 26.

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.

We reported previously that high numbers of mast cells in benign (extra-tumoral) regions of the prostate are associated with worse outcomes after radical prostatectomy including biochemical recurrence and the development of metastases. Herein, with a cohort of 384 men, we performed mast cell subtyping and report that higher minimum number of the tryptase-only (MC ) subset of extra-tumoral mast cells is associated with increased risk of biochemical recurrence (comparing highest to lowest tertiles: HR 2.32, 95% CI 1.37-3.93; P-trend = 0.002), metastases (HR 3.62, 95% CI 1.75-7.47; P-trend 0.001), and death from prostate cancer (HR 2.87, 95% CI 1.19-6.95; P-trend = 0.02). Preliminary RNA sequencing and comparison of benign versus cancer tissue mast cells revealed differential expression of additional site-specific genes. We further demonstrate that the genes CXCR4 and TFE3 are more highly expressed in tumor-infiltrating mast cells as well as other tumor-infiltrating immune cells and in tumor cells, respectively, and represent an altered tumor microenvironment. KIT variants were also differentially expressed in benign versus cancer tissue mast cells, with KIT variant 1 (GNNK ) mast cells identified as more prevalent in extra-tumoral regions of the prostate. Finally, using an established mouse model, we found that mast cells do not infiltrate Hi-Myc tumors, providing a model to specifically examine the role of extra-tumoral mast cells in tumorigenesis. Hi-Myc mice crossed to mast cell knockout (Wsh) mice and aged to 1 year revealed a higher degree of pre-invasive lesions and invasive cancer in wild-type mice versus heterozygous and knockout mice. This suggests a dosage effect where higher numbers of extra-tumoral mast cells resulted in higher cancer invasion. Overall, our studies provide further evidence for a role of extra-tumoral mast cells in driving adverse prostate cancer outcomes. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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http://dx.doi.org/10.1002/path.5606DOI Listing
April 2021

Impact of Sex on Clinical Response in Rheumatoid Arthritis Patients Treated With Biologics at Approved Dosing Regimens.

J Clin Pharmacol 2020 12;60 Suppl 2:S103-S109

Division of Quantitative Methods and Modeling, Office of Research and Standards, Office of Generic Drugs, US Food and Drug Administration, Silver Spring, Maryland, USA.

The prevalence of rheumatoid arthritis (RA) is higher in females than in males. With the development of new treatment options and strategies such as biologics, we found it worthwhile to identify whether males and females warrant different treatment regimens to ensure the best clinical response. Our meta-analysis included 11 clinical trials of RA patients in support of the Food and Drug Administration's approval of 6 biological products. We evaluated the data of American College of Rheumatology 20 (ACR20) 24 or 26 weeks after treatment. Logistic regression models were applied to compute the odds ratio (OR) of treatment responses between sexes. The ORs of ACR20 response rates in males and females were similar across all studies and not significantly different in overall studies (OR, 1.05; 95% confidence interval, 0.96-1.16) analyzed with a fixed-effects model. Further analyses on the 7 ACR20 subcomponents showed high heterogeneity among studies (Q statistic P < .00007, I > 95%), with no observed clinically meaningful sex-related difference. Thus, our meta-analysis did not find significant difference in ACR20 response rates between male and female RA patients treated with biologics at approved dosing regimens. This result supports the current clinical practice of not requiring sex-dependent treatment regimens for RA patients.
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http://dx.doi.org/10.1002/jcph.1776DOI Listing
December 2020

Skin intrinsic fluorescence scores are a predictor of all-cause mortality risk in type 1 diabetes: The Epidemiology of Diabetes Complications study.

J Diabetes Complications 2021 Feb 23;35(2):107770. Epub 2020 Oct 23.

University of Pittsburgh, Graduate School of Public Health, Department of Epidemiology, School of Public Health, 130 De Soto Street, Pittsburgh, PA 15231, USA.

Aims: We assessed the association of skin intrinsic fluorescence (SIF) scores, as a measure of advanced glycation end-products (AGE), with all-cause mortality in type 1 diabetes (T1D).

Methods: This is an observational retrospective study of a convenience sample from the Epidemiology of Diabetes Complications (EDC) study. AGEs were measured with a SIF score between 2007 and 2014; vital status was assessed in 2020.

Results: Among 245 participants, mean age was 48.6 ± 7.4 years, median diabetes duration was 39.5 years (IQR: 34.2, 44.9), and 53.5% were female. Compared to survivors, the deceased (n = 20) were older, with higher SIF scores, longer diabetes duration, lower body mass index (BMI), and an adverse risk factor profile (all p≤0.05). Univariate Cox regression showed a marginal association between SIF score and mortality (HR: 1.1, 95% CI 0.9-1.2, p = 0.06), which persisted after adjustment for multiple daily insulin shots/pump (MDI) use (HR: 1.1, 95% CI 1.0-1.2, p = 0.04). This association was attenuated after adjustment for T1D duration, A months, or estimated glomerular filtration rate (eGFR).

Conclusions: In individuals with long duration T1D, SIF scores adjusted for MDI predicted all-cause mortality, although this association was attenuated after adjustments. Given the nature of sampling and small number of events, our findings require replication.
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http://dx.doi.org/10.1016/j.jdiacomp.2020.107770DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7855847PMC
February 2021

Ultrasound-triggered therapeutic microbubbles enhance the efficacy of cytotoxic drugs by increasing circulation and tumor drug accumulation and limiting bioavailability and toxicity in normal tissues.

Theranostics 2020 1;10(24):10973-10992. Epub 2020 Sep 1.

Leeds Institute of Medical Research, Wellcome Trust Brenner Building, St James's University Hospital, Leeds, LS9 7TF, United Kingdom.

Most cancer patients receive chemotherapy at some stage of their treatment which makes improving the efficacy of cytotoxic drugs an ongoing and important goal. Despite large numbers of potent anti-cancer agents being developed, a major obstacle to clinical translation remains the inability to deliver therapeutic doses to a tumor without causing intolerable side effects. To address this problem, there has been intense interest in nanoformulations and targeted delivery to improve cancer outcomes. The aim of this work was to demonstrate how vascular endothelial growth factor receptor 2 (VEGFR2)-targeted, ultrasound-triggered delivery with therapeutic microbubbles (thMBs) could improve the therapeutic range of cytotoxic drugs. Using a microfluidic microbubble production platform, we generated thMBs comprising VEGFR2-targeted microbubbles with attached liposomal payloads for localised ultrasound-triggered delivery of irinotecan and SN38 in mouse models of colorectal cancer. Intravenous injection into tumor-bearing mice was used to examine targeting efficiency and tumor pharmacodynamics. High-frequency ultrasound and bioluminescent imaging were used to visualise microbubbles in real-time. Tandem mass spectrometry (LC-MS/MS) was used to quantitate intratumoral drug delivery and tissue biodistribution. Finally, Zr PET radiotracing was used to compare biodistribution and tumor accumulation of ultrasound-triggered SN38 thMBs with VEGFR2-targeted SN38 liposomes alone. ThMBs specifically bound VEGFR2 and significantly improved tumor responses to low dose irinotecan and SN38 in human colorectal cancer xenografts. An ultrasound trigger was essential to achieve the selective effects of thMBs as without it, thMBs failed to extend intratumoral drug delivery or demonstrate enhanced tumor responses. Sensitive LC-MS/MS quantification of drugs and their metabolites demonstrated that thMBs extended drug exposure in tumors but limited exposure in healthy tissues, not exposed to ultrasound, by persistent encapsulation of drug prior to elimination. Zr PET radiotracing showed that the percentage injected dose in tumors achieved with thMBs was twice that of VEGFR2-targeted SN38 liposomes alone. thMBs provide a generic platform for the targeted, ultrasound-triggered delivery of cytotoxic drugs by enhancing tumor responses to low dose drug delivery via combined effects on circulation, tumor drug accumulation and exposure and altered metabolism in normal tissues.
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http://dx.doi.org/10.7150/thno.49670DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7532679PMC
September 2020

Methods for Enrichment and Assignment of N-Acetylglucosamine Modification Sites.

Mol Cell Proteomics 2020 Sep 16. Epub 2020 Sep 16.

Mass Spectrometry Facility, University of California San Francisco, United States

O-GlcNAcylation, the addition of a single N-acetylglucosamine residue to serine and threonine residues of cytoplasmic, nuclear, or mitochondrial proteins, is a widespread regulatory post-translational modification. It is involved in response to nutritional status and stress and its dysregulation is associated with diseases ranging from Alzheimer's to diabetes.  While the modification was first detected over thirty-five years ago, research into the function of O-GlcNAcylation has accelerated dramatically in the last ten years due to the development of new enrichment and mass spectrometry techniques that facilitate its analysis.  This article summarizes methods for O-GlcNAc enrichment, key mass spectrometry instrumentation advancements, particularly those that allow modification site localization, and software tools that allow analysis of data from O-GlcNAc modified peptides.
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http://dx.doi.org/10.1074/mcp.R120.002206DOI Listing
September 2020

FDA orphan products clinical trial grants: assessment of outcomes and impact on rare disease product development.

Orphanet J Rare Dis 2020 09 3;15(1):234. Epub 2020 Sep 3.

US Food and Drug Administration, Office of the Commissioner, Office of Orphan Products Development, 10903 New Hampshire Avenue, Silver Spring, MD, 20993, USA.

Background: The Office of Orphan Products Development (OOPD) of the United States (U.S.) Food and Drug Administration (FDA) has awarded over 700 grants to conduct clinical trials of medicals products for rare diseases since 1983, leading to over 70 marketing approvals. However, despite recent progress in rare disease product development, thousands of rare diseases still have no approved treatments. An assessment of this clinical trial grants program was undertaken to provide an in-depth analysis of the characteristics and outcomes of the program. Results of this analysis will be used to inform future goals of the program, as well as internal data collection to continue to maximize the program's impact in supporting rare disease product development.

Results: Between fiscal years 2007-2011, OOPD funded 85 clinical trial grants. These grants spanned 18 therapeutic areas, included all pre-approval phases (Phases 1-3), and approximately 75% of the grants studied small molecule drugs. Nine (11%) product approvals, of seven drugs and two devices, were at least partially supported by grants funded within this 5-year timeframe. Four of the seven drugs approved were new molecular entities (NMEs). The average time from funding to approval was seven years. We also found a suggested association between collaboration with multiple types of stakeholders and the success of grants, where we defined success as either positive or negative study findings or a future marketing approval.

Conclusions: The clinical trials funded by OOPD provided valuable information for future product development, and there were a notable number of approvals that occurred using the support of the grants program. There was a suggested association between collaboration and successful outcomes. Efficient and innovative trial designs and collaboration among stakeholders appear vital to continue to effectively bring products to rare disease patients. Ongoing program assessments will ensure that the funding continues to be used to optimally meet the treatment needs of the rare disease community.
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http://dx.doi.org/10.1186/s13023-020-01514-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7469294PMC
September 2020

Eigenfunction orthogonality for one-dimensional acoustic systems with interior or end point conditions.

Authors:
J D Maynard

J Acoust Soc Am 2020 Aug;148(2):627

Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

Some common exercises presented in introductory acoustics courses and texts illustrate solutions involving eigenvalues and eigenfunctions. Challenging extensions of these, even for one-dimensional (1D) systems, might involve a mass or spring loading the acoustic medium at an end point or at an interior point. These problems might be extended further by requiring that some given function be expanded in a series of the eigenfunctions, but such extended problems may lead to unexpected complications in regard to eigenfunction orthogonality. In this paper, Sturm-Liouville theory is used to develop a systematic method for predetermining eigenfunction orthogonality for 1D systems loaded at end points or interior points or having properties that change with jump discontinuities.
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http://dx.doi.org/10.1121/10.0001601DOI Listing
August 2020

Age-related loss of neural stem cell O-GlcNAc promotes a glial fate switch through STAT3 activation.

Proc Natl Acad Sci U S A 2020 09 26;117(36):22214-22224. Epub 2020 Aug 26.

Department of Anatomy, University of California, San Francisco, CA 94143;

Increased neural stem cell (NSC) quiescence is a major determinant of age-related regenerative decline in the adult hippocampus. However, a coextensive model has been proposed in which division-coupled conversion of NSCs into differentiated astrocytes restrict the stem cell pool with age. Here we report that age-related loss of the posttranslational modification, O-linked β--acetylglucosamine (O-GlcNAc), in NSCs promotes a glial fate switch. We detect an age-dependent decrease in NSC O-GlcNAc levels coincident with decreased neurogenesis and increased gliogenesis in the mature hippocampus. Mimicking an age-related loss of NSC O-GlcNAcylation in young mice reduces neurogenesis, increases astrocyte differentiation, and impairs associated cognitive function. Using RNA-sequencing of primary NSCs following decreased O-GlcNAcylation, we detected changes in the STAT3 signaling pathway indicative of glial differentiation. Moreover, using O-GlcNAc-specific mass spectrometry analysis of the aging hippocampus, together with an in vitro site-directed mutagenesis approach, we identify loss of STAT3 O-GlcNAc at Threonine 717 as a driver of astrocyte differentiation. Our data identify the posttranslational modification, O-GlcNAc, as a key molecular regulator of regenerative decline underlying an age-related NSC fate switch.
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http://dx.doi.org/10.1073/pnas.2007439117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7486730PMC
September 2020

Cytosolic N-GlcNAc proteins are formed by the action of endo-β-N-acetylglucosaminidase.

Biochem Biophys Res Commun 2020 10 8;530(4):719-724. Epub 2020 Aug 8.

Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA 94158, USA.

NGLY1 is a widely conserved eukaryotic cytosolic deglycosylating enzyme involved in the endoplasmic reticulum-associated degradation (ERAD) process, which eliminates misfolded proteins through retrograde translocation and proteasomal degradation. A human genetic disorder called NGLY1-deficiency has been reported, indicating the functional importance of NGLY1 in humans. Evidence suggests that Ngly1-KO is embryonic lethal in mice, while additional deletion of the Engase gene, encoding another cytosolic deglycosylating enzyme (endo-β-N-acetylglucosaminidase; ENGase), partially rescued lethality. Upon compromised Ngly1 activity, ENGase-mediated deglycosylation of misfolded glycoproteins may cause excess formation of N-GlcNAc proteins in the cytosol, leading to detrimental effects in the mice. Whether endogenous N-GlcNAc proteins are really formed in Ngly1-KO cells/animals or not remains unclarified. Here, comprehensive identification of O- and N-GlcNAc proteins was carried out using purified cytosol from wild type, Ngly1-KO, Engase-KO, and Ngly1/Engase double KO mouse embryonic fibroblasts. It was revealed that while there is no dramatic change in the level of O-GlcNAc proteins among cells examined, there was a vast increase of N-GlcNAc proteins in Ngly1-KO cells upon proteasome inhibition. Importantly, few N-GlcNAc proteins were observed in Engase-KO or Ngly1/Engase double-KO cells, clearly indicating that the cytosolic ENGase is responsible for the formation of N-GlcNAc proteins. The excess formation of N-GlcNAc proteins may at least in part account for the pathogenesis of NGLY1-deficiency.
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http://dx.doi.org/10.1016/j.bbrc.2020.06.127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7508226PMC
October 2020

Structure-based design of prefusion-stabilized SARS-CoV-2 spikes.

Science 2020 09 23;369(6510):1501-1505. Epub 2020 Jul 23.

Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA.

The coronavirus disease 2019 (COVID-19) pandemic has led to accelerated efforts to develop therapeutics and vaccines. A key target of these efforts is the spike (S) protein, which is metastable and difficult to produce recombinantly. We characterized 100 structure-guided spike designs and identified 26 individual substitutions that increased protein yields and stability. Testing combinations of beneficial substitutions resulted in the identification of HexaPro, a variant with six beneficial proline substitutions exhibiting higher expression than its parental construct (by a factor of 10) as well as the ability to withstand heat stress, storage at room temperature, and three freeze-thaw cycles. A cryo-electron microscopy structure of HexaPro at a resolution of 3.2 angstroms confirmed that it retains the prefusion spike conformation. High-yield production of a stabilized prefusion spike protein will accelerate the development of vaccines and serological diagnostics for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).
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http://dx.doi.org/10.1126/science.abd0826DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402631PMC
September 2020

The timed barium swallow and its relationship to symptoms in achalasia: Analysis of surface area and emptying rate.

Neurogastroenterol Motil 2020 12 23;32(12):e13928. Epub 2020 Jun 23.

GI Physiology Unit, University College London Hospital, London, UK.

Background: Timed barium swallow (TBS) is used to objectively measure response following achalasia therapy; however, findings can be discordant with symptoms. We hypothesized that measurement of surface area of the residual barium column would improve its utility in measuring outcome.

Methods: In a single-center cohort, achalasia patients undergoing therapy between September 2015-2016 who had TBS were included. Four metrics of emptying were studied: Post-therapy residual barium (a) absolute height and (b) surface area and percentage reduction in (c) residual height (%H) and (d) surface area (%SA) compared to pretherapy. Metrics were evaluated against symptom response (Eckardt score).

Key Results: Twenty-four achalasics (median age 43 year; 13 males) were included; 14 received pneumatic dilatation, and 10 had peroral endoscopic myotomy. Treatment resulted in significant reduction in median Eckardt score (7 to 1; P = .03), mean residual barium column height (14.7 ± 8.7 to 7.9 ± 6.0 cm; P = .01) and surface area (52.7 ± 43.5 to 24.5 ± 23.6 cm ; P = .02). There were 4 (17%) initial non-responders (Eckardt > 3). % SA was best at discriminating between responders and non-responders (area under curve 0.85 ± 0.08; sensitivity 100%, specificity 80%). Concordance with symptomatic response following therapy was 83% when using 45% as the cutoff for surface area reduction compared to pretherapy. Eight patients whose static barium height was discordant with symptoms became concordant when % SA was used as a measure of response.

Conclusions & Inferences: Change in barium surface area is a superior measure of esophageal emptying and better correlates with treatment response than the conventional 5-minute barium height in defining objective response to achalasia therapy.
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http://dx.doi.org/10.1111/nmo.13928DOI Listing
December 2020

Structure-based Design of Prefusion-stabilized SARS-CoV-2 Spikes.

bioRxiv 2020 May 30. Epub 2020 May 30.

Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712.

The COVID-19 pandemic caused by the novel coronavirus SARS-CoV-2 has led to accelerated efforts to develop therapeutics, diagnostics, and vaccines to mitigate this public health emergency. A key target of these efforts is the spike (S) protein, a large trimeric class I fusion protein that is metastable and difficult to produce recombinantly in large quantities. Here, we designed and expressed over 100 structure-guided spike variants based upon a previously determined cryo-EM structure of the prefusion SARS-CoV-2 spike. Biochemical, biophysical and structural characterization of these variants identified numerous individual substitutions that increased protein yields and stability. The best variant, HexaPro, has six beneficial proline substitutions leading to ~10-fold higher expression than its parental construct and is able to withstand heat stress, storage at room temperature, and multiple freeze-thaws. A 3.2 Å-resolution cryo-EM structure of HexaPro confirmed that it retains the prefusion spike conformation. High-yield production of a stabilized prefusion spike protein will accelerate the development of vaccines and serological diagnostics for SARS-CoV-2.
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http://dx.doi.org/10.1101/2020.05.30.125484DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7302215PMC
May 2020

A facile technology for the high-throughput sequencing of the paired VH:VL and TCRβ:TCRα repertoires.

Sci Adv 2020 Apr 22;6(17):eaay9093. Epub 2020 Apr 22.

Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA.

Natively paired sequencing (NPS) of B cell receptors [variable heavy (VH) and light (VL)] and T cell receptors (TCRb and TCRa) is essential for the understanding of adaptive immunity in health and disease. Despite many recent technical advances, determining the VH:VL or TCRb:a repertoire with high accuracy and throughput remains challenging. We discovered that the recently engineered xenopolymerase, RTX, is exceptionally resistant to cell lysate inhibition in single-cell emulsion droplets. We capitalized on the characteristics of this enzyme to develop a simple, rapid, and inexpensive in-droplet overlap extension reverse transcription polymerase chain reaction method for NPS not requiring microfluidics or other specialized equipment. Using this technique, we obtained high yields (5000 to >20,000 per sample) of paired VH:VL or TCRb:a clonotypes at low cost. As a demonstration, we performed NPS on peripheral blood plasmablasts and T follicular helper cells following seasonal influenza vaccination and discovered high-affinity influenza-specific antibodies and TCRb:a.
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http://dx.doi.org/10.1126/sciadv.aay9093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7176429PMC
April 2020

Effects of Solriamfetol on Quality-of-Life Measures from a 12-Week Phase 3 Randomized Controlled Trial.

Ann Am Thorac Soc 2020 08;17(8):998-1007

SleepMed, Inc., Columbia, South Carolina; and.

Excessive daytime sleepiness in patients with obstructive sleep apnea is associated with substantial burden of illness. To assess treatment effects of solriamfetol, a dopamine/norepinephrine reuptake inhibitor, on daily functioning, health-related quality of life, and work productivity in participants with obstructive sleep apnea and excessive daytime sleepiness as additional outcomes in a 12-week phase 3 trial (www.clinicaltrials.gov identifier NCT02348606). Participants ( = 476) were randomized to solriamfetol 37.5, 75, 150, or 300 mg or to placebo. Outcome measures included the Functional Outcomes of Sleep Questionnaire short version, Work Productivity and Activity Impairment Questionnaire: Specific Health Problem, and 36-item Short Form Health Survey version 2. A mixed-effects model with repeated measures was used for comparisons with placebo. Demographics, baseline disease characteristics, daily functioning, health-related quality of life, and work productivity were similar across groups. At Week 12, increased functioning and decreased impairment were observed with solriamfetol 150 and 300 mg (mean difference from placebo [95% confidence interval]) on the basis of Functional Outcomes of Sleep Questionnaire total score (1.22 [0.57 to 1.88] and 1.47 [0.80 to 2.13], respectively), overall work impairment (-11.67 [-19.66 to -3.69] and -11.75 [-19.93 to -3.57], respectively), activity impairment (-10.42 [-16.37 to -4.47] and -10.51 [-16.59 to -4.43], respectively), physical component summary (2.07 [0.42 to 3.72] and 1.91 [0.22 to 3.59], respectively), and mental component summary (150 mg only, 2.05 [0.14 to 3.96]). Common adverse events were headache, nausea, decreased appetite, and anxiety. Solriamfetol improved measures of functioning, quality of life, and work productivity in participants with obstructive sleep apnea and excessive daytime sleepiness. Safety was consistent with previous studies.Clinical trial registered with www.clinicaltrials.gov (NCT02348606).
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http://dx.doi.org/10.1513/AnnalsATS.202002-136OCDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7393785PMC
August 2020

World Health Organization Grade II/III Glioma Molecular Status: Prediction by MRI Morphologic Features and Apparent Diffusion Coefficient.

Radiology 2020 07 21;296(1):111-121. Epub 2020 Apr 21.

From the Neuroradiological Academic Unit, Department of Brain, Repair and Rehabilitation, UCL Institute of Neurology, London, England (J.M., S.O., S.W., L.M., R.J., S.T.); Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, England (S.W., A.A.B., W.M., A.M.K., L.M., R.J., S.T.); Population, Policy and Practice Research Unit, UCL Great Ormond Street Institute of Child Health, London, England (O.A.); Department of Neurodegenerative Disease, UCL Institute of Neurology and Division of Neuropathology, National Hospital for Neurology and Neurosurgery, London, England (S.B., Z.J.); Department of Radiology, Izmir Bozyaka Education and Research Hospital, Izmir, Turkey (A.M.K.); and Department of Imaging, University College London Foundation Hospital, London, England (R.J., S.T.).

Background A readily implemented MRI biomarker for glioma genotyping is currently lacking. Purpose To evaluate clinically available MRI parameters for predicting isocitrate dehydrogenase () status in patients with glioma. Materials and Methods In this retrospective study of patients studied from July 2008 to February 2019, untreated World Health Organization (WHO) grade II/III gliomas were analyzed by three neuroradiologists blinded to tissue results. Apparent diffusion coefficient (ADC) minimum (ADC) and mean (ADC) regions of interest were defined in tumor and normal appearing white matter (ADC). A visual rating of anatomic features (T1 weighted, T1 weighted with contrast enhancement, T2 weighted, and fluid-attenuated inversion recovery) was performed. Interobserver comparison (intraclass correlation coefficient and Cohen κ) was followed by nonparametric (Kruskal-Wallis analysis of variance) testing of associations between ADC metrics and glioma genotypes, including Bonferroni correction for multiple testing. Descriptors with sufficient concordance (intraclass correlation coefficient, >0.8; κ > 0.6) underwent univariable analysis. Predictive variables ( < .05) were entered into a multivariable logistic regression and tested in an additional test sample of patients with glioma. Results The study included 290 patients (median age, 40 years; interquartile range, 33-52 years; 169 male patients) with 82 wild-type, 107 mutant/1p19q intact, and 101 mutant/1p19q codeleted gliomas. Two predictive models incorporating ADC-to-ADC ratio, age, and morphologic characteristics, with model A mandating calcification result and model B recording cyst formation, classified tumor type with areas under the receiver operating characteristic curve of 0.94 (95% confidence interval [CI]: 0.91, 0.97) and 0.96 (95% CI: 0.93, 0.98), respectively. In the test sample of 49 gliomas (nine wild type, 21 mutant/ intact, and 19 mutant/ codeleted), the classification accuracy was 40 of 49 gliomas (82%; 95% CI: 71%, 92%) for model A and 42 of 49 gliomas (86%; 95% CI: 76%, 96%) for model B. Conclusion Two algorithms that incorporated apparent diffusion coefficient values, age, and tumor morphologic characteristics predicted isocitrate dehydrogenase status in World Health Organization grade II/III gliomas on the basis of standard clinical MRI sequences alone. © RSNA, 2020
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http://dx.doi.org/10.1148/radiol.2020191832DOI Listing
July 2020

Noninferiority Trials to Evaluate Drug Effects in Rheumatoid Arthritis.

Arthritis Rheumatol 2020 08 19;72(8):1258-1265. Epub 2020 Jun 19.

FDA, Silver Springs, Maryland.

Objective: The increased availability of highly effective treatments in rheumatoid arthritis (RA) necessitates a reexamination of study designs evaluating new treatments. We undertook this study to discuss possible specifications and considerations of noninferiority (NI) trials assessing drug effects in RA.

Methods: We focused on the use of approved tumor necrosis factor inhibitors (TNFi) as potential active controls and reviewed previous placebo-controlled studies. We summarized the similarities in baseline characteristics and study design of the historical placebo-controlled studies used. After performing meta-analyses to estimate the effects of TNFi on symptoms, physical function, and radiographic progression in RA, we proposed NI margins and evaluated the feasibility of NI trials in this therapeutic setting.

Results: We determined that an NI trial comparing an experimental treatment to a TNFi using the symptomatic end point of the American College of Rheumatology 20% improvement criteria response can feasibly provide evidence of a treatment effect, with a 12% absolute difference as one possible appropriate NI margin. For change from baseline in the Health Assessment Questionnaire disability index score, reasonable margins range from 0.10 to 0.12. In evaluating radiographic progression, an appropriate margin and the corresponding feasibility of the trial are dependent on the selected active control and the expected variability in progression.

Conclusion: Active-controlled studies in RA with justified NI margins can provide persuasive evidence of treatment effects on symptomatic, functional, and radiographic end points. Such studies can also provide reliable, controlled safety data and relevant information for treatment decisions in clinical practice. Thus, we recommend considering NI designs in future clinical trials in RA.
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http://dx.doi.org/10.1002/art.41257DOI Listing
August 2020

Rethinking Patient and Medical Professional Perspectives on Bariatric Surgery as a Medically Necessary Treatment.

Mayo Clin Proc 2020 03;95(3):527-540

Division of General Surgery, Mayo Clinic, Jacksonville, FL.

The prevalence of class 3 obesity (body mass index ≥40 kg/m) is 7.7% of the United States adult population; thus, more than 25 million people may be medically appropriate for consideration of bariatric surgery as therapy for severe obesity. Although bariatric surgery is the most effective therapy for patients with severe obesity, the surgery is performed in less than 1% of patients annually for whom it may be appropriate. Patients' and medical professionals' misperceptions about obesity and bariatric surgery create barriers to accessing bariatric surgery that are not given adequate attention and clinical consideration. Commonly cited patient barriers are lack of knowledge about the severity of obesity, the perception that obesity is a lifestyle problem rather than a chronic disease, and fear that bariatric surgery is dangerous. Medical professional barriers include failing to recognize causes of obesity and weight gain, providing recommendations that are inconsistent with current obesity treatment guidelines, and being uncomfortable counseling patients about treatment options for severe obesity. Previous research has revealed that medical professional counseling and accurate perception of the health risks associated with severe obesity are strong predictors of patients' willingness to consider bariatric surgery. This article reviews patient and medical professional barriers to acceptance of bariatric surgery as a treatment of medical necessity and offers practical advice for medical professionals to rethink perspectives about bariatric surgery when it is medically and psychologically appropriate.
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http://dx.doi.org/10.1016/j.mayocp.2019.09.019DOI Listing
March 2020

A Pivotal Study to Validate the Performance of a Novel Wearable Sensor and System for Biometric Monitoring in Clinical and Remote Environments.

Digit Biomark 2019 Jan-Apr;3(1):1-13. Epub 2019 Mar 1.

MC10 Inc., Lexington, Massachusetts, USA.

Background: Increasingly, drug and device clinical trials are tracking activity levels and other quality of life indices as endpoints for therapeutic efficacy. Trials have traditionally required intermittent subject visits to the clinic that are artificial, activity-intensive, and infrequent, making trend and event detection between visits difficult. Thus, there is an unmet need for wearable sensors that produce clinical quality and medical grade physiological data from subjects in the home. The current study was designed to validate the BioStamp nPoint® system (MC10 Inc., Lexington, MA, USA), a new technology designed to meet this need.

Objective: To evaluate the accuracy, performance, and ease of use of an end-to-end system called the BioStamp nPoint. The system consists of an investigator portal for design of trials and data review, conformal, low-profile, wearable biosensors that adhere to the skin, a companion technology for wireless data transfer to a proprietary cloud, and algorithms for analyzing physiological, biometric, and contextual data for clinical research.

Methods: A prospective, nonrandomized clinical trial was conducted on 30 healthy adult volunteers over the course of two continuous days and nights. Supervised and unsupervised study activities enabled performance validation in clinical and remote (simulated "at home") environments. System outputs for heart rate (HR), heart rate variability (HRV) (including root mean square of successive differences [RMSSD] and low frequency/high frequency ratio), activity classification during prescribed activities (lying, sitting, standing, walking, stationary biking, and sleep), step count during walking, posture characterization, and sleep metrics including onset/wake times, sleep duration, and respiration rate (RR) during sleep were evaluated. Outputs were compared to FDA-cleared comparator devices for HR, HRV, and RR and to ground truth investigator observations for activity and posture classifications, step count, and sleep events.

Results: Thirty participants (77% male, 23% female; mean age 35.9 ± 10.1 years; mean BMI 28.1 ± 3.6) were enrolled in the study. The BioStamp nPoint system accurately measured HR and HRV (correlations: HR = 0.957, HRV RMSSD = 0.965, HRV ratio = 0.861) when compared to ActiheartTM. The system accurately monitored RR (mean absolute error [MAE] = 1.3 breaths/min) during sleep when compared to a Capnostream35TM end-tidal CO2 monitor. When compared with investigator observations, the system correctly classified activities and posture (agreement = 98.7 and 92.9%, respectively), step count (MAE = 14.7, < 3% of actual steps during a 6-min walk), and sleep events (MAE: sleep onset = 6.8 min, wake = 11.5 min, sleep duration = 13.7 min) with high accuracy. Participants indicated "good" to "excellent" usability (average System Usability Scale score of 81.3) and preferred the BioStamp nPoint system over both the Actiheart (86%) and Capnostream (97%) devices.

Conclusions: The present study validated the BioStamp nPoint system's performance and ease of use compared to FDA-cleared comparator devices in both the clinic and remote (home) environments.
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http://dx.doi.org/10.1159/000493642DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7015390PMC
March 2019

Neutralization of pertussis toxin by a single antibody prevents clinical pertussis in neonatal baboons.

Sci Adv 2020 02 5;6(6):eaay9258. Epub 2020 Feb 5.

Department of Chemical Engineering, University of Texas at Austin, Austin, TX 78712, USA.

Pertussis continues to cause considerable infant mortality world-wide, which could be addressed in part by passive immunization strategies. Antibody hu1B7 is a candidate therapeutic that potently neutralizes pertussis toxin in vitro, prevents leukocytosis in mice and treats established disease in weanling baboons as part of an antibody cocktail. Here, we evaluated the potential for hu1B7 and an extended half-life hu1B7 variant to prevent death, leukocytosis and other clinical symptoms in a newborn baboon model that mimics many aspects of human disease. We administered a single antibody dose to newborn baboons five weeks prior to experimental infection. While all animals were heavily colonized with , prophylaxed animals showed significantly greater survival ( < 0.005), delayed and suppressed leukocytosis ( < 0.01) and enhanced clinical outcomes, including coughing ( < 0.01), as compared to controls. Together, this work demonstrates that a single neutralizing anti-PTx antibody is sufficient to prevent clinical pertussis symptoms.
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http://dx.doi.org/10.1126/sciadv.aay9258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7002138PMC
February 2020

The increasing importance of sports science and medicine.

J Int Med Res 2020 Jan;48(1):300060519827694

Primary Care Sports Medicine, Mayo Clinic, Jacksonville, FL, United States.

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http://dx.doi.org/10.1177/0300060519827694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140197PMC
January 2020

High-resolution 3D visualization of nanomedicine distribution in tumors.

Theranostics 2020 1;10(2):880-897. Epub 2020 Jan 1.

Bioscience, Discovery, Oncology R&D, AstraZeneca, Cambridge, United Kingdom.

To improve the clinical translation of anti-cancer nanomedicines, it is necessary to begin building specific insights into the broad concept of the Enhanced Permeability and Retention (EPR) effect, using detailed investigations of the accumulation, distribution and retention of nanomedicines in solid tumors. Nanomedicine accumulation in preclinical tumors has been extensively studied; however, treatment efficacy will be heavily influenced by both the quantity of drug-loaded nanomedicines reaching the tumor as well as their spatial distribution throughout the tumor. It remains a challenge to image the heterogeneity of nanomedicine distribution in 3 dimensions within solid tumors with a high degree of spatial resolution using standard imaging approaches. To achieve this, an ex vivo micro computed tomography (µCT) imaging approach was developed to visualize the intratumoral distribution of contrast agent-loaded PEGylated liposomes. Using this semi-quantitative method, whole 3-dimensional (3D) tumor liposome distribution was determined with 17 µm resolution in a phenotypically diverse panel of four preclinical xenograft and patient-derived explant (PDX) tumor models. High-resolution ex vivo μCT imaging revealed striking differences in liposome distribution within tumors in four models with different vascular patterns and densities, stromal contents, and microenvironment morphologies. Following intravenous dosing, the model with the highest density of pericyte-supported vessels showed the greatest liposome accumulation, while the model with vessels present in regions of high α-smooth muscle actin (αSMA) content presented with a large proportion of the liposomes at depths beyond the tumor periphery. The two models with an unsupported vascular network demonstrated a more restricted pattern of liposome distribution. Taken together, vessel distribution and support (the latter indicative of functionality) appear to be key factors determining the accumulation and distribution pattern of liposomes in tumors. Our findings demonstrate that high-resolution 3D visualization of nanomedicine distribution is a useful tool for preclinical nanomedicine research, providing valuable insights into the influence of the tumor vasculature and microenvironment on nanomedicine localization.
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http://dx.doi.org/10.7150/thno.37178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6929971PMC
January 2020

The Opportunities and Use of Imaging to Measure Target Engagement.

SLAS Discov 2020 02 29;25(2):127-136. Epub 2019 Dec 29.

Medicines Discovery Catapult, Alderley Park, Cheshire, UK.

Lack of efficacy and poor safety outcomes are deemed to be the greatest causes of clinical failure of novel therapeutics. The use of biomarkers that give accurate information on target engagement, providing confidence that pharmacological activity in the target organ is being achieved, is key in optimizing clinical success. Without a measurement of target engagement, it can be very difficult to discern the basis for any lack of efficacy of a drug molecule within the pharmaceutical industry. Target engagement can be measured in both an in vitro and in vivo setting, and in recent years imaging measurements have been used frequently in drug discovery and development to assess target engagement and receptor occupancy in both human and animal models. From this perspective, we assess and look at the advancements in both in vivo and ex vivo imaging to demonstrate the enormous potential that imaging has as an application to provide a greater understanding of target engagement with a correlative therapeutic impact.
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http://dx.doi.org/10.1177/2472555219897270DOI Listing
February 2020

Prey-size plastics are invading larval fish nurseries.

Proc Natl Acad Sci U S A 2019 11 11;116(48):24143-24149. Epub 2019 Nov 11.

School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5AB, United Kingdom.

Life for many of the world's marine fish begins at the ocean surface. Ocean conditions dictate food availability and govern survivorship, yet little is known about the habitat preferences of larval fish during this highly vulnerable life-history stage. Here we show that surface slicks, a ubiquitous coastal ocean convergence feature, are important nurseries for larval fish from many ocean habitats at ecosystem scales. Slicks had higher densities of marine phytoplankton (1.7-fold), zooplankton (larval fish prey; 3.7-fold), and larval fish (8.1-fold) than nearby ambient waters across our study region in Hawai'i. Slicks contained larger, more well-developed individuals with competent swimming abilities compared to ambient waters, suggesting a physiological benefit to increased prey resources. Slicks also disproportionately accumulated prey-size plastics, resulting in a 60-fold higher ratio of plastics to larval fish prey than nearby waters. Dissections of hundreds of larval fish found that 8.6% of individuals in slicks had ingested plastics, a 2.3-fold higher occurrence than larval fish from ambient waters. Plastics were found in 7 of 8 families dissected, including swordfish (Xiphiidae), a commercially targeted species, and flying fish (Exocoetidae), a principal prey item for tuna and seabirds. Scaling up across an ∼1,000 km coastal ecosystem in Hawai'i revealed slicks occupied only 8.3% of ocean surface habitat but contained 42.3% of all neustonic larval fish and 91.8% of all floating plastics. The ingestion of plastics by larval fish could reduce survivorship, compounding threats to fisheries productivity posed by overfishing, climate change, and habitat loss.
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http://dx.doi.org/10.1073/pnas.1907496116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6883795PMC
November 2019

Engineering Antibodies on the Surface of CHO Cells.

Methods Mol Biol 2020 ;2070:397-422

Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA.

While antibody libraries are traditionally screened in phage, bacterial, or yeast display formats, they are produced in large scale for pharmaceutical and commercial use in mammalian cell lines. The simpler organisms used for screening have significantly different folding and glycosylation machinery than mammalian cells; consequently, clones resulting from these libraries may require further optimization for mammalian cell expression. To streamline the antibody discovery process, we developed a Chinese hamster ovary (CHO) cell-based selection system that allows for long-term display of antibody Fab fragments. This system is facilitated by a semi-stable Epi-CHO episomal platform to maintain antibody expression for up to 2 months and is compatible with standard PCR-based mutagenesis strategies. This protocol describes the simple and accessible use of CHO display coupled with flow cytometry to enrich for antibody variants with increased ligand-binding affinity from large libraries of ~10 variants, using HER2-binding antibodies as an example.
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http://dx.doi.org/10.1007/978-1-4939-9853-1_22DOI Listing
December 2020

IL8 Expression Is Associated with Prostate Cancer Aggressiveness and Androgen Receptor Loss in Primary and Metastatic Prostate Cancer.

Mol Cancer Res 2020 01 11;18(1):153-165. Epub 2019 Oct 11.

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Chronic inflammation and African ancestry are implicated in prostate cancer aggressiveness, and inflammation-related genes are more highly expressed in prostate cancer in African American men. IL8 secretion is also implicated in prostate cancer progression and castration resistance. We used RNA hybridization to localize IL1β, IL6, IL8, and IL10 mRNA in low- and high-grade prostate cancer from African American and European American men. IL8 was the most abundantly expressed and the only interleukin detected in tumor cells. We further interrogated IL8 expression in primary and metastatic prostate cancer tissue microarrays and both androgen-dependent and castration-resistant patient-derived xenografts (PDX). IL8 was significantly increased in both tumor and benign regions of higher grade cases (ISUP Grade Group 4-5), but there was no difference between races. We determined that IL8 expression in prostate cancer cell lines, distant metastases, and PDX lines was associated with androgen receptor (AR) loss, but not castration resistance. Reciprocal IL8 and AR expression was also observed in high IL8-expressing atrophy lesions with simultaneous AR downregulation. Finally, we show that IL8 is likely repressed by AR binding to the IL8 promoter and is inducible in prostate cancer cells stimulated with lipopolysaccharide only in cells with AR loss. Likewise, AR knockdown in androgen-dependent cells induced IL8 expression, further demonstrating that AR represses IL8 expression. In conclusion, IL8 expression in the tumor microenvironment is associated with aggressive prostate cancer and with AR loss in metastatic disease. IMPLICATIONS: IL8 expression is repressed by AR and is associated with prostate cancer aggressiveness and AR loss in metastatic disease.
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http://dx.doi.org/10.1158/1541-7786.MCR-19-0595DOI Listing
January 2020

Lactoferrin CpG Island Hypermethylation and Decoupling of mRNA and Protein Expression in the Early Stages of Prostate Carcinogenesis.

Am J Pathol 2019 11 6;189(11):2311-2322. Epub 2019 Sep 6.

Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland; Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address:

Lactoferrin (LTF) is an iron-binding protein canonically known for its innate and adaptive immune functions. LTF may also act as a tumor suppressor with antiproliferative action. LTF is inactivated genetically or epigenetically in various cancers, and a CpG island spanning the transcriptional start site of LTF is hypermethylated in prostate cancer cell lines. We, therefore, hypothesized that LTF expression is silenced via CpG island hypermethylation in the early stages of prostate tumorigenesis carcinogenesis. Targeted methylation analysis was performed using a combination of methylated-DNA precipitation and methylation-sensitive restriction enzymes, and laser-capture microdissection followed by bisulfite sequencing on DNA isolated from prostate tissue samples, including both primary and metastatic disease. LTF mRNA in situ hybridization and LTF protein immunohistochemistry were also performed. We report that the LTF CpG island is frequently and densely methylated in high-grade prostatic intraepithelial neoplasia, primary prostate carcinoma, and metastases. We further report a decoupling of lactoferrin mRNA and protein expression, including in lesions where LTF mRNA has presumably been silenced via CpG island methylation. We conclude that LTF mRNA expression is silenced in prostate tumorigenesis via hypermethylation, supporting a role for LTF as a prostate cancer tumor suppressor gene. Likewise, the frequency at which the LTF CpG island is methylated across samples suggests it is an important and conserved step in prostate cancer initiation.
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http://dx.doi.org/10.1016/j.ajpath.2019.07.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6892185PMC
November 2019