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Petersen TB, de Bakker M, Asselbergs FW, Harakalova M, Akkerhuis KM, Brugts JJ, van Ramshorst J, Lumbers RT, Ostroff RM, Katsikis PD, van der Spek PJ, Umans VA, Boersma E, Rizopoulos D, Kardys I. HFrEF subphenotypes based on 4210 repeatedly measured circulating proteins are driven by different biological mechanisms. EBioMedicine 2023; 93:104655. [PMID: 37327673 DOI: 10.1016/j.ebiom.2023.104655] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/31/2023] [Accepted: 05/31/2023] [Indexed: 06/18/2023] Open
Abstract
BACKGROUND HFrEF is a heterogenous condition with high mortality. We used serial assessments of 4210 circulating proteins to identify distinct novel protein-based HFrEF subphenotypes and to investigate underlying dynamic biological mechanisms. Herewith we aimed to gain pathophysiological insights and fuel opportunities for personalised treatment. METHODS In 382 patients, we performed trimonthly blood sampling during a median follow-up of 2.1 [IQR:1.1-2.6] years. We selected all baseline samples and two samples closest to the primary endpoint (PEP; composite of cardiovascular mortality, HF hospitalization, LVAD implantation, and heart transplantation) or censoring, and applied an aptamer-based multiplex proteomic approach. Using unsupervised machine learning methods, we derived clusters from 4210 repeatedly measured proteomic biomarkers. Sets of proteins that drove cluster allocation were analysed via an enrichment analysis. Differences in clinical characteristics and PEP occurrence were evaluated. FINDINGS We identified four subphenotypes with different protein profiles, prognosis and clinical characteristics, including age (median [IQR] for subphenotypes 1-4, respectively:70 [64, 76], 68 [60, 79], 57 [47, 65], 59 [56, 66]years), EF (30 [26, 36], 26 [20, 38], 26 [22, 32], 33 [28, 37]%), and chronic renal failure (45%, 65%, 36%, 37%). Subphenotype allocation was driven by subsets of proteins associated with various biological functions, such as oxidative stress, inflammation and extracellular matrix organisation. Clinical characteristics of the subphenotypes were aligned with these associations. Subphenotypes 2 and 3 had the worst prognosis compared to subphenotype 1 (adjHR (95%CI):3.43 (1.76-6.69), and 2.88 (1.37-6.03), respectively). INTERPRETATION Four circulating-protein based subphenotypes are present in HFrEF, which are driven by varying combinations of protein subsets, and have different clinical characteristics and prognosis. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT01851538https://clinicaltrials.gov/ct2/show/NCT01851538. FUNDING EU/EFPIA IMI2JU BigData@Heart grant n°116074, Jaap Schouten Foundation and Noordwest Academie.
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Affiliation(s)
- Teun B Petersen
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands; Department of Biostatistics, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Marie de Bakker
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Folkert W Asselbergs
- Amsterdam University Medical Centers, Department of Cardiology, University of Amsterdam, Meibergdreef 9, Amsterdam, the Netherlands; Health Data Research UK and Institute of Health Informatics, University College London, Gower St, London, United Kingdom
| | - Magdalena Harakalova
- Department of Cardiology, Division Heart and Lungs, University Medical Center Utrecht, University of Utrecht, Heidelberglaan 100, Utrecht, the Netherlands; Regenerative Medicine Center Utrecht, University Medical Center Utrecht, University of Utrecht, Heidelberglaan 100, Utrecht, the Netherlands
| | - K Martijn Akkerhuis
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Jasper J Brugts
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Jan van Ramshorst
- Department of Cardiology, Northwest Clinics, Wilhelminalaan 12, Alkmaar, the Netherlands
| | - R Thomas Lumbers
- British Heart Foundation Research Accelerator, University College London, Gower St, London, UK; Institute of Health Informatics, University College London, Gower St, London, UK; Health Data Research UK London, University College London, Gower St, London, UK
| | | | - Peter D Katsikis
- Department of Immunology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Peter J van der Spek
- Department of Pathology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Victor A Umans
- Department of Cardiology, Northwest Clinics, Wilhelminalaan 12, Alkmaar, the Netherlands
| | - Eric Boersma
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Dimitris Rizopoulos
- Department of Biostatistics, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands
| | - Isabella Kardys
- Department of Cardiology, Erasmus MC, University Medical Center Rotterdam, Doctor Molewaterplein 40, Rotterdam, the Netherlands.
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Ferrannini G, Manca ML, Magnoni M, Andreotti F, Andreini D, Latini R, Maseri A, Maggioni AP, Ostroff RM, Williams SA, Ferrannini E. Erratum. Coronary Artery Disease and Type 2 Diabetes: A Proteomic Study. Diabetes Care 2020;43:843-851. Diabetes Care 2021; 44:1071. [PMID: 33483359 DOI: 10.2337/dc21-er04a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Ferrannini E, Murthy AC, Lee YH, Muscelli E, Weiss S, Ostroff RM, Sattar N, Williams SA, Ganz P. Mechanisms of Sodium-Glucose Cotransporter 2 Inhibition: Insights From Large-Scale Proteomics. Diabetes Care 2020; 43:2183-2189. [PMID: 32527800 DOI: 10.2337/dc20-0456] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 04/24/2020] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To assess the effects of empagliflozin, a selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, on broad biological systems through proteomics. RESEARCH DESIGN AND METHODS Aptamer-based proteomics was used to quantify 3,713 proteins in 144 paired plasma samples obtained from 72 participants across the spectrum of glucose tolerance before and after 4 weeks of empagliflozin 25 mg/day. The biology of the plasma proteins significantly changed by empagliflozin (at false discovery rate-corrected P < 0.05) was discerned through Ingenuity Pathway Analysis. RESULTS Empagliflozin significantly affected levels of 43 proteins, 6 related to cardiomyocyte function (fatty acid-binding protein 3 and 4 [FABPA], neurotrophic receptor tyrosine kinase, renin, thrombospondin 4, and leptin receptor), 5 to iron handling (ferritin heavy chain 1, transferrin receptor protein 1, neogenin, growth differentiation factor 2 [GDF2], and β2-microglobulin), and 1 to sphingosine/ceramide metabolism (neutral ceramidase), a known pathway of cardiovascular disease. Among the protein changes achieving the strongest statistical significance, insulin-like binding factor protein-1 (IGFBP-1), transgelin-2, FABPA, GDF15, and sulphydryl oxidase 2 precursor were increased, while ferritin, thrombospondin 3, and Rearranged during Transfection (RET) were decreased by empagliflozin administration. CONCLUSIONS SGLT2 inhibition is associated, directly or indirectly, with multiple biological effects, including changes in markers of cardiomyocyte contraction/relaxation, iron handling, and other metabolic and renal targets. The most significant differences were detected in protein species (GDF15, ferritin, IGFBP-1, and FABP) potentially related to the clinical and metabolic changes that were actually measured in the same patients. These novel results may inform further studies using targeted proteomics and a prospective design.
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Affiliation(s)
| | - Ashwin C Murthy
- Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA
| | - Yong-Ho Lee
- Department of Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | | | | | | | - Naveed Sattar
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, U.K
| | | | - Peter Ganz
- Zuckerberg San Francisco General Hospital, University of California, San Francisco, CA
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Ferrannini G, Manca ML, Magnoni M, Andreotti F, Andreini D, Latini R, Maseri A, Maggioni AP, Ostroff RM, Williams SA, Ferrannini E. Coronary Artery Disease and Type 2 Diabetes: A Proteomic Study. Diabetes Care 2020; 43:843-851. [PMID: 31988066 DOI: 10.2337/dc19-1902] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 12/31/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Coronary artery disease (CAD) is a major challenge in patients with type 2 diabetes (T2D). Coronary computed tomography angiography (CCTA) provides a detailed anatomic map of the coronary circulation. Proteomics are increasingly used to improve diagnostic and therapeutic algorithms. We hypothesized that the protein panel is differentially associated with T2D and CAD. RESEARCH DESIGN AND METHODS In CAPIRE (Coronary Atherosclerosis in Outlier Subjects: Protective and Novel Individual Risk Factors Evaluation-a cohort of 528 individuals with no previous cardiovascular event undergoing CCTA), participants were grouped into CAD- (clean coronaries) and CAD+ (diffuse lumen narrowing or plaques). Plasma proteins were screened by aptamer analysis. Two-way partial least squares was used to simultaneously rank proteins by diabetes status and CAD. RESULTS Though CAD+ was more prevalent among participants with T2D (HbA1c 6.7 ± 1.1%) than those without diabetes (56 vs. 30%, P < 0.0001), CCTA-based atherosclerosis burden did not differ. Of the 20 top-ranking proteins, 15 were associated with both T2D and CAD, and 3 (osteomodulin, cartilage intermediate-layer protein 15, and HTRA1) were selectively associated with T2D only and 2 (epidermal growth factor receptor and contactin-1) with CAD only. Elevated renin and GDF15, and lower adiponectin, were independently associated with both T2D and CAD. In multivariate analysis adjusting for the Framingham risk panel, patients with T2D were "protected" from CAD if female (P = 0.007), younger (P = 0.021), and with lower renin levels (P = 0.02). CONCLUSIONS We concluded that 1) CAD severity and quality do not differ between participants with T2D and without diabetes; 2) renin, GDF15, and adiponectin are shared markers by T2D and CAD; 3) several proteins are specifically associated with T2D or CAD; and 4) in T2D, lower renin levels may protect against CAD.
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Affiliation(s)
- Giulia Ferrannini
- Department of Medical Sciences, Postgraduate School of Internal Medicine, University of Turin, Turin, Italy.,Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Maria Laura Manca
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Marco Magnoni
- IRCCS Ospedale San Raffaele and Università Vita-Salute San Raffaele, Milan, Italy
| | - Felicita Andreotti
- Institute of Cardiology, FPG IRCCS, Catholic University Medical School, Rome, Italy
| | - Daniele Andreini
- Centro Cardiologico Monzino, IRCCS, Milan, Italy.,Cardiovascular Section, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Roberto Latini
- Mario Negri Institute of Pharmacological Research-IRCCS, Milan, Italy
| | | | - Aldo P Maggioni
- ANMCO Research Center, Heart Care Foundation, Florence, Italy
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Jung YJ, Katilius E, Ostroff RM, Kim Y, Seok M, Lee S, Jang S, Kim WS, Choi CM. Development of a Protein Biomarker Panel to Detect Non-Small-Cell Lung Cancer in Korea. Clin Lung Cancer 2016; 18:e99-e107. [PMID: 27836219 DOI: 10.1016/j.cllc.2016.09.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND Lung cancer screening using low-dose computed tomography reduces lung cancer mortality. However, the high false-positive rate, cost, and potential harms highlight the need for complementary biomarkers. We compared the diagnostic performance of modified aptamer-based protein biomarkers with Cyfra 21-1. PATIENTS AND METHODS Participants included 100 patients diagnosed with lung cancer, and 100 control subjects from Asan Medical Center (Seoul, Korea). We investigated candidate biomarkers with new modified aptamer-based proteomic technology and developed a 7-protein panel that discriminates lung cancer from controls. A naive Bayesian classifier was trained using sera from 75 lung cancers and 75 controls. An independent set of 25 cases and 25 controls was used to verify performance of this classifier. The panel results were compared with Cyfra 21-1 to evaluate the diagnostic accuracy for lung nodules detected by computed tomography. RESULTS We derived a 7-protein biomarker classifier from the initial train set comprising: EGFR1, MMP7, CA6, KIT, CRP, C9, and SERPINA3. This classifier distinguished lung cancer cases from controls with an area under the curve (AUC) of 0.82 in the train set and an AUC of 0.77 in the verification set. The 7-marker naive Bayesian classifier resulted in 91.7% specificity with 75.0% sensitivity for the subset of individuals with lung nodules. The AUC of the classifier for lung nodules was 0.88, whereas Cyfra 21-1 had an AUC of 0.72. CONCLUSION We have developed a protein biomarker panel to identify lung cancers from controls with a high accuracy. This integrated noninvasive approach to the evaluation of lung nodules deserves further prospective validation among larger cohorts of patients with lung nodules in screening strategy.
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Affiliation(s)
- Young Ju Jung
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea; Health Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | | | | | | | | | - Sujin Lee
- Aptamer Sciences Inc., Pohang, Korea
| | - Seongsoo Jang
- Department of Laboratory Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Woo Sung Kim
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Chang-Min Choi
- Department of Pulmonary and Critical Care Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
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Vasil ML, Graham LM, Ostroff RM, Shortridge VD, Vasil AI. Phospholipase C: molecular biology and contribution to the pathogenesis of Pseudomonas aeruginosa. Antibiot Chemother (1971) 2015; 44:34-47. [PMID: 1801644 DOI: 10.1159/000420295] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- M L Vasil
- Department of Microbiology and Immunology, University of Colorado Health Sciences Center, Denver
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Mehan MR, Williams SA, Siegfried JM, Bigbee WL, Weissfeld JL, Wilson DO, Pass HI, Rom WN, Muley T, Meister M, Franklin W, Miller YE, Brody EN, Ostroff RM. Validation of a blood protein signature for non-small cell lung cancer. Clin Proteomics 2014; 11:32. [PMID: 25114662 PMCID: PMC4123246 DOI: 10.1186/1559-0275-11-32] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 07/14/2014] [Indexed: 02/07/2023] Open
Abstract
Background CT screening for lung cancer is effective in reducing mortality, but there are areas of concern, including a positive predictive value of 4% and development of interval cancers. A blood test that could manage these limitations would be useful, but development of such tests has been impaired by variations in blood collection that may lead to poor reproducibility across populations. Results Blood-based proteomic profiles were generated with SOMAscan technology, which measured 1033 proteins. First, preanalytic variability was evaluated with Sample Mapping Vectors (SMV), which are panels of proteins that detect confounders in protein levels related to sample collection. A subset of well collected serum samples not influenced by preanalytic variability was selected for discovery of lung cancer biomarkers. The impact of sample collection variation on these candidate markers was tested in the subset of samples with higher SMV scores so that the most robust markers could be used to create disease classifiers. The discovery sample set (n = 363) was from a multi-center study of 94 non-small cell lung cancer (NSCLC) cases and 269 long-term smokers and benign pulmonary nodule controls. The analysis resulted in a 7-marker panel with an AUC of 0.85 for all cases (68% adenocarcinoma, 32% squamous) and an AUC of 0.93 for squamous cell carcinoma in particular. This panel was validated by making blinded predictions in two independent cohorts (n = 138 in the first validation and n = 135 in the second). The model was recalibrated for a panel format prior to unblinding the second cohort. The AUCs overall were 0.81 and 0.77, and for squamous cell tumors alone were 0.89 and 0.87. The estimated negative predictive value for a 15% disease prevalence was 93% overall and 99% for squamous lung tumors. The proteins in the classifier function in destruction of the extracellular matrix, metabolic homeostasis and inflammation. Conclusions Selecting biomarkers resistant to sample processing variation led to robust lung cancer biomarkers that performed consistently in independent validations. They form a sensitive signature for detection of lung cancer, especially squamous cell histology. This non-invasive test could be used to improve the positive predictive value of CT screening, with the potential to avoid invasive evaluation of nonmalignant pulmonary nodules.
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Affiliation(s)
| | | | - Jill M Siegfried
- University of Pittsburgh Cancer Institute, School of Medicine, Pittsburgh, PA, USA ; University of Minnesota, Minneapolis, MN, USA
| | - William L Bigbee
- University of Pittsburgh Cancer Institute, School of Medicine, Pittsburgh, PA, USA
| | - Joel L Weissfeld
- Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, USA
| | - David O Wilson
- University of Pittsburgh Cancer Institute, School of Medicine, Pittsburgh, PA, USA
| | - Harvey I Pass
- Langone Medical Center and Cancer Center, New York University School of Medicine, New York, NY, USA
| | - William N Rom
- New York University School of Medicine, New York, NY, USA
| | - Thomas Muley
- Thoraxklinik at University Hospital Heidelberg and Translational Lung Research Center Heidelberg (TLRC-H), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Michael Meister
- Thoraxklinik at University Hospital Heidelberg and Translational Lung Research Center Heidelberg (TLRC-H), Member of the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Wilbur Franklin
- University of Colorado Cancer Center, University of Colorado School of Medicine, Aurora, CO, USA
| | - York E Miller
- University of Colorado Cancer Center, University of Colorado School of Medicine, Aurora, CO, USA ; Denver Veterans Affairs Medical Center, Denver, CO, USA
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Ostroff RM, Mehan MR, Stewart A, Ayers D, Brody EN, Williams SA, Levin S, Black B, Harbut M, Carbone M, Goparaju C, Pass HI. Early detection of malignant pleural mesothelioma in asbestos-exposed individuals with a noninvasive proteomics-based surveillance tool. PLoS One 2012; 7:e46091. [PMID: 23056237 PMCID: PMC3463527 DOI: 10.1371/journal.pone.0046091] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 08/27/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Malignant pleural mesothelioma (MM) is an aggressive, asbestos-related pulmonary cancer that is increasing in incidence. Because diagnosis is difficult and the disease is relatively rare, most patients present at a clinically advanced stage where possibility of cure is minimal. To improve surveillance and detection of MM in the high-risk population, we completed a series of clinical studies to develop a noninvasive test for early detection. METHODOLOGY/PRINCIPAL FINDINGS We conducted multi-center case-control studies in serum from 117 MM cases and 142 asbestos-exposed control individuals. Biomarker discovery, verification, and validation were performed using SOMAmer proteomic technology, which simultaneously measures over 1000 proteins in unfractionated biologic samples. Using univariate and multivariate approaches we discovered 64 candidate protein biomarkers and derived a 13-marker random forest classifier with an AUC of 0.99±0.01 in training, 0.98±0.04 in independent blinded verification and 0.95±0.04 in blinded validation studies. Sensitivity and specificity at our pre-specified decision threshold were 97%/92% in training and 90%/95% in blinded verification. This classifier accuracy was maintained in a second blinded validation set with a sensitivity/specificity of 90%/89% and combined accuracy of 92%. Sensitivity correlated with pathologic stage; 77% of Stage I, 93% of Stage II, 96% of Stage III and 96% of Stage IV cases were detected. An alternative decision threshold in the validation study yielding 98% specificity would still detect 60% of MM cases. In a paired sample set the classifier AUC of 0.99 and 91%/94% sensitivity/specificity was superior to that of mesothelin with an AUC of 0.82 and 66%/88% sensitivity/specificity. The candidate biomarker panel consists of both inflammatory and proliferative proteins, processes strongly associated with asbestos-induced malignancy. SIGNIFICANCE The SOMAmer biomarker panel discovered and validated in these studies provides a solid foundation for surveillance and diagnosis of MM in those at highest risk for this disease.
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Affiliation(s)
- Rachel M Ostroff
- Clinical Research, SomaLogic Inc., Boulder, Colorado, United States of America.
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Mehan MR, Ayers D, Thirstrup D, Xiong W, Ostroff RM, Brody EN, Walker JJ, Gold L, Jarvis TC, Janjic N, Baird GS, Wilcox SK. Protein signature of lung cancer tissues. PLoS One 2012; 7:e35157. [PMID: 22509397 PMCID: PMC3324437 DOI: 10.1371/journal.pone.0035157] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/09/2012] [Indexed: 12/13/2022] Open
Abstract
Lung cancer remains the most common cause of cancer-related mortality. We applied a highly multiplexed proteomic technology (SOMAscan) to compare protein expression signatures of non small-cell lung cancer (NSCLC) tissues with healthy adjacent and distant tissues from surgical resections. In this first report of SOMAscan applied to tissues, we highlight 36 proteins that exhibit the largest expression differences between matched tumor and non-tumor tissues. The concentrations of twenty proteins increased and sixteen decreased in tumor tissue, thirteen of which are novel for NSCLC. NSCLC tissue biomarkers identified here overlap with a core set identified in a large serum-based NSCLC study with SOMAscan. We show that large-scale comparative analysis of protein expression can be used to develop novel histochemical probes. As expected, relative differences in protein expression are greater in tissues than in serum. The combined results from tissue and serum present the most extensive view to date of the complex changes in NSCLC protein expression and provide important implications for diagnosis and treatment.
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Affiliation(s)
| | - Deborah Ayers
- SomaLogic, Inc., Boulder, Colorado, United States of America
| | - Derek Thirstrup
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Wei Xiong
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | | | - Edward N. Brody
- SomaLogic, Inc., Boulder, Colorado, United States of America
| | | | - Larry Gold
- SomaLogic, Inc., Boulder, Colorado, United States of America
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Thale C. Jarvis
- SomaLogic, Inc., Boulder, Colorado, United States of America
| | - Nebojsa Janjic
- SomaLogic, Inc., Boulder, Colorado, United States of America
| | - Geoffrey S. Baird
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Sheri K. Wilcox
- SomaLogic, Inc., Boulder, Colorado, United States of America
- * E-mail:
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Pass HI, Mehan M, Ostroff RM, Stewart A, Levin S, Black B, Harbut M, Williams SA. Abstract 2812: Detection of mesothelioma in asbestos exposed individuals with aptamer proteomic technology. Cancer Res 2011. [DOI: 10.1158/1538-7445.am2011-2812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Malignant pleural mesothelioma is an aggressive, asbestos-related pulmonary cancer which is increasing in incidence. This disease causes an estimated 15,000 to 20,000 deaths per year worldwide. Between 1940 and 1979, approximately 27.5 million people were occupationally exposed to asbestos in the United States. The incidence of pleural mesothelioma in the US is 3,000 new cases/year and will not peak for another 20 years. Mesothelioma has a latency period of 20-40 years from asbestos exposure, but once diagnosed this aggressive disease is often fatal within 14 months. Because diagnosis is difficult, most patients present at a clinically advanced stage where possibility of cure is minimal. Therefore, we have conducted a broad search for new serum biomarkers with our aptamer-based proteomic platform and defined a classifier for the detection of mesothelioma in asbestos exposed individuals.
Secreted proteins and those released during apoptosis from tumor cells and surrounding tissues contain important biologic information that may enable early diagnosis and prognostic and therapeutic decisions in oncology. However, there is great difficulty in finding and quantifying such signals for large numbers of low abundance proteins. We therefore created a highly multiplexed proteomic assay that currently measures ∼850 proteins simultaneously from 15ul blood, with throughput of 300 samples/day. The average dynamic range of each protein in the assay is >3 logs – with nearly seven logs of dynamic range achieved through multiple dilutions – and the median lower limit of quantification is below 1 pM. The median coefficient of variation for each protein is <5%. This assay performance arises from the selection of high affinity aptamers that bind selectively to their target proteins with slow off-rates.
The objective of this study was to discover proteins which are involved in malignant mesothelioma and to develop algorithms and classifiers for detection of the disease. To this end, blood samples from three study centers were analyzed with the aptamer proteomics platform in a prospectively designed case:control study. We compared 170 serum samples from 90 patients diagnosed with malignant mesothelioma to 80 asbestos exposed controls. These samples were divided into 75% for training and 25% set aside as a blinded test set for classifier development and verification.
Nineteen significant biomarkers were discovered by applying a backwards selection strategy. Classifiers were built with subsets of these biomarkers resulting in an AUC of 0.95 or better with an overall accuracy of 93%. Applying a 13-plex Random Forest classifier to the blinded test set resulted in a specificity of 100% and sensitivity of 80% for distinction of asbestos exposed controls from mesothelioma, including detection of 15/19 Stage I/II cases. Refinement and confirmation of classifier performance will be established through ongoing validation studies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2812. doi:10.1158/1538-7445.AM2011-2812
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Affiliation(s)
- Harvey I. Pass
- 1NYU Langone Medical Center and Cancer Center, New York, NY
| | | | | | | | | | - Brad Black
- 4Libby MT Center for Asbestos Related Diseases, Libby, MT
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Ostroff RM, Bigbee WL, Franklin W, Gold L, Mehan M, Miller YE, Pass HI, Rom WN, Siegfried JM, Stewart A, Walker JJ, Weissfeld JL, Williams S, Zichi D, Brody EN. Unlocking biomarker discovery: large scale application of aptamer proteomic technology for early detection of lung cancer. PLoS One 2010; 5:e15003. [PMID: 21170350 PMCID: PMC2999620 DOI: 10.1371/journal.pone.0015003] [Citation(s) in RCA: 166] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 10/07/2010] [Indexed: 02/08/2023] Open
Abstract
Background Lung cancer is the leading cause of cancer deaths worldwide. New diagnostics are needed to detect early stage lung cancer because it may be cured with surgery. However, most cases are diagnosed too late for curative surgery. Here we present a comprehensive clinical biomarker study of lung cancer and the first large-scale clinical application of a new aptamer-based proteomic technology to discover blood protein biomarkers in disease. Methodology/Principal Findings We conducted a multi-center case-control study in archived serum samples from 1,326 subjects from four independent studies of non-small cell lung cancer (NSCLC) in long-term tobacco-exposed populations. Sera were collected and processed under uniform protocols. Case sera were collected from 291 patients within 8 weeks of the first biopsy-proven lung cancer and prior to tumor removal by surgery. Control sera were collected from 1,035 asymptomatic study participants with ≥10 pack-years of cigarette smoking. We measured 813 proteins in each sample with a new aptamer-based proteomic technology, identified 44 candidate biomarkers, and developed a 12-protein panel (cadherin-1, CD30 ligand, endostatin, HSP90α, LRIG3, MIP-4, pleiotrophin, PRKCI, RGM-C, SCF-sR, sL-selectin, and YES) that discriminates NSCLC from controls with 91% sensitivity and 84% specificity in cross-validated training and 89% sensitivity and 83% specificity in a separate verification set, with similar performance for early and late stage NSCLC. Conclusions/Significance This study is a significant advance in clinical proteomics in an area of high unmet clinical need. Our analysis exceeds the breadth and dynamic range of proteome interrogated of previously published clinical studies of broad serum proteome profiling platforms including mass spectrometry, antibody arrays, and autoantibody arrays. The sensitivity and specificity of our 12-biomarker panel improves upon published protein and gene expression panels. Separate verification of classifier performance provides evidence against over-fitting and is encouraging for the next development phase, independent validation. This careful study provides a solid foundation to develop tests sorely needed to identify early stage lung cancer.
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Affiliation(s)
- Rachel M. Ostroff
- SomaLogic, Boulder, Colorado, United States of America
- * E-mail: (RMO); (JJW)
| | - William L. Bigbee
- Department of Pathology, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America
| | - Wilbur Franklin
- University of Colorado Cancer Center, University of Colorado at Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Larry Gold
- SomaLogic, Boulder, Colorado, United States of America
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
| | - Mike Mehan
- SomaLogic, Boulder, Colorado, United States of America
| | - York E. Miller
- University of Colorado Cancer Center, University of Colorado at Denver, Anschutz Medical Campus, Aurora, Colorado, United States of America
- Denver Veterans Affairs Medical Center, Denver, Colorado, United States of America
| | - Harvey I. Pass
- Langone Medical Center and Cancer Center, New York University School of Medicine, New York, New York, United States of America
| | - William N. Rom
- Division of Pulmonary, and Critical Care, and Sleep Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Jill M. Siegfried
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America
| | - Alex Stewart
- SomaLogic, Boulder, Colorado, United States of America
| | - Jeffrey J. Walker
- SomaLogic, Boulder, Colorado, United States of America
- * E-mail: (RMO); (JJW)
| | - Joel L. Weissfeld
- Department of Epidemiology, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania, United States of America
| | | | - Dom Zichi
- SomaLogic, Boulder, Colorado, United States of America
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12
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Gold L, Ayers D, Bertino J, Bock C, Bock A, Brody EN, Carter J, Dalby AB, Eaton BE, Fitzwater T, Flather D, Forbes A, Foreman T, Fowler C, Gawande B, Goss M, Gunn M, Gupta S, Halladay D, Heil J, Heilig J, Hicke B, Husar G, Janjic N, Jarvis T, Jennings S, Katilius E, Keeney TR, Kim N, Koch TH, Kraemer S, Kroiss L, Le N, Levine D, Lindsey W, Lollo B, Mayfield W, Mehan M, Mehler R, Nelson SK, Nelson M, Nieuwlandt D, Nikrad M, Ochsner U, Ostroff RM, Otis M, Parker T, Pietrasiewicz S, Resnicow DI, Rohloff J, Sanders G, Sattin S, Schneider D, Singer B, Stanton M, Sterkel A, Stewart A, Stratford S, Vaught JD, Vrkljan M, Walker JJ, Watrobka M, Waugh S, Weiss A, Wilcox SK, Wolfson A, Wolk SK, Zhang C, Zichi D. Aptamer-based multiplexed proteomic technology for biomarker discovery. PLoS One 2010; 5:e15004. [PMID: 21165148 PMCID: PMC3000457 DOI: 10.1371/journal.pone.0015004] [Citation(s) in RCA: 1032] [Impact Index Per Article: 73.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 10/13/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The interrogation of proteomes ("proteomics") in a highly multiplexed and efficient manner remains a coveted and challenging goal in biology and medicine. METHODOLOGY/PRINCIPAL FINDINGS We present a new aptamer-based proteomic technology for biomarker discovery capable of simultaneously measuring thousands of proteins from small sample volumes (15 µL of serum or plasma). Our current assay measures 813 proteins with low limits of detection (1 pM median), 7 logs of overall dynamic range (~100 fM-1 µM), and 5% median coefficient of variation. This technology is enabled by a new generation of aptamers that contain chemically modified nucleotides, which greatly expand the physicochemical diversity of the large randomized nucleic acid libraries from which the aptamers are selected. Proteins in complex matrices such as plasma are measured with a process that transforms a signature of protein concentrations into a corresponding signature of DNA aptamer concentrations, which is quantified on a DNA microarray. Our assay takes advantage of the dual nature of aptamers as both folded protein-binding entities with defined shapes and unique nucleotide sequences recognizable by specific hybridization probes. To demonstrate the utility of our proteomics biomarker discovery technology, we applied it to a clinical study of chronic kidney disease (CKD). We identified two well known CKD biomarkers as well as an additional 58 potential CKD biomarkers. These results demonstrate the potential utility of our technology to rapidly discover unique protein signatures characteristic of various disease states. CONCLUSIONS/SIGNIFICANCE We describe a versatile and powerful tool that allows large-scale comparison of proteome profiles among discrete populations. This unbiased and highly multiplexed search engine will enable the discovery of novel biomarkers in a manner that is unencumbered by our incomplete knowledge of biology, thereby helping to advance the next generation of evidence-based medicine.
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Affiliation(s)
- Larry Gold
- SomaLogic, Boulder, Colorado, United States of America
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado, United States of America
- * E-mail: (LG); (JJW)
| | - Deborah Ayers
- SomaLogic, Boulder, Colorado, United States of America
| | | | | | - Ashley Bock
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Jeff Carter
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Bruce E. Eaton
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, United States of America
| | - Tim Fitzwater
- SomaLogic, Boulder, Colorado, United States of America
| | - Dylan Flather
- SomaLogic, Boulder, Colorado, United States of America
| | - Ashley Forbes
- SomaLogic, Boulder, Colorado, United States of America
| | - Trudi Foreman
- SomaLogic, Boulder, Colorado, United States of America
| | - Cate Fowler
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Meredith Goss
- SomaLogic, Boulder, Colorado, United States of America
| | - Magda Gunn
- SomaLogic, Boulder, Colorado, United States of America
| | - Shashi Gupta
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Jim Heil
- SomaLogic, Boulder, Colorado, United States of America
| | - Joe Heilig
- SomaLogic, Boulder, Colorado, United States of America
| | - Brian Hicke
- SomaLogic, Boulder, Colorado, United States of America
| | - Gregory Husar
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Thale Jarvis
- SomaLogic, Boulder, Colorado, United States of America
| | | | | | | | - Nancy Kim
- SomaLogic, Boulder, Colorado, United States of America
| | - Tad H. Koch
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, United States of America
| | | | - Luke Kroiss
- SomaLogic, Boulder, Colorado, United States of America
| | - Ngan Le
- SomaLogic, Boulder, Colorado, United States of America
| | - Daniel Levine
- The Rogosin Institute and the Weill Medical College of Cornell University, New York, New York, United States of America
| | - Wes Lindsey
- SomaLogic, Boulder, Colorado, United States of America
| | - Bridget Lollo
- SomaLogic, Boulder, Colorado, United States of America
| | - Wes Mayfield
- SomaLogic, Boulder, Colorado, United States of America
| | - Mike Mehan
- SomaLogic, Boulder, Colorado, United States of America
| | - Robert Mehler
- SomaLogic, Boulder, Colorado, United States of America
| | | | | | | | - Malti Nikrad
- SomaLogic, Boulder, Colorado, United States of America
| | - Urs Ochsner
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Matt Otis
- SomaLogic, Boulder, Colorado, United States of America
| | - Thomas Parker
- The Rogosin Institute and the Weill Medical College of Cornell University, New York, New York, United States of America
| | | | | | - John Rohloff
- SomaLogic, Boulder, Colorado, United States of America
| | - Glenn Sanders
- SomaLogic, Boulder, Colorado, United States of America
| | - Sarah Sattin
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Britta Singer
- SomaLogic, Boulder, Colorado, United States of America
| | | | - Alana Sterkel
- SomaLogic, Boulder, Colorado, United States of America
| | - Alex Stewart
- SomaLogic, Boulder, Colorado, United States of America
| | | | | | - Mike Vrkljan
- SomaLogic, Boulder, Colorado, United States of America
| | - Jeffrey J. Walker
- SomaLogic, Boulder, Colorado, United States of America
- * E-mail: (LG); (JJW)
| | - Mike Watrobka
- SomaLogic, Boulder, Colorado, United States of America
| | - Sheela Waugh
- SomaLogic, Boulder, Colorado, United States of America
| | - Allison Weiss
- SomaLogic, Boulder, Colorado, United States of America
| | | | | | | | - Chi Zhang
- SomaLogic, Boulder, Colorado, United States of America
| | - Dom Zichi
- SomaLogic, Boulder, Colorado, United States of America
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13
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Abstract
BACKGROUND S-100B is a protein mainly found in astroglial cells and only detected to a low level in blood. Serum levels of S-100B increase in patients with acute brain injuries. The aim of this study was to establish feasibility of a new Optical ImmunoAssay ([OIA], Bio-Star, Inc, Boulder, CO) test for determination of S-100B in blood. METHODS We have developed a new, rapid, and sensitive OIA test to identify elevated levels of S-100B in whole blood. The OIA test for S-100B combines monoclonal antibodies specific for the B-subunit of S-100 with OIA thin film technology. Each sample was tested for S-100B by the OIA method and a commercially available immunoluminometric assay. Blood samples were drawn serially from 9 patients undergoing coronary artery bypass graft surgery and during the early postoperative period. RESULTS The OIA test determination of S-100B protein correlated with immunoluminometric assay data (r = 0.8) with a detection limit of 0.25 ng/mL. CONCLUSIONS The sensitivity and feasibility of this rapid assay may be suitable for rapid evaluation of S-100B in urgent care settings (surgery, intensive care units, or emergency room).
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Affiliation(s)
- A Ettinger
- BioStar, Inc, Boulder, Colorado 80301, USA.
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14
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Ostroff RM, Hopkins D, Haeberli AB, Baouchi W, Polisky B. Thin film biosensor for rapid visual detection of nucleic acid targets. Clin Chem 1999; 45:1659-64. [PMID: 10471680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND We have developed a silicon-based biosensor that generates a visual signal in response to nucleic acid targets. METHODS In this system, capture oligonucleotide probes are immobilized on the surface of the biosensor. Interaction of the capture probes with a complementary target and a biotinylated detector oligonucleotide allows initiation of formation of an organic thin film on the biosensor. Thin film formation is completed by enzymatic activity of peroxidase conjugated to an anti-biotin antibody. Peroxidase catalyzes deposition of an insoluble product onto the silicon surface, generating a uniform thin film. The increased thickness on the surface alters the perceived color of the biosensor through changes in the interference patterns of reflected light from the surface, causing a color change from gold to purple. RESULTS The biosensor results may be evaluated by direct visual inspection or quantified by ellipsometry. Results are obtained in 25 min with a detection limit of 5 pmol/L (150 amol/sample). Selectivity of the biosensor is demonstrated by discrimination of single nucleotide mismatches. Multitarget arrays are also analyzed with the thin film biosensor, and the system is capable of detecting targets from human serum and urine. CONCLUSIONS The biosensor surface is inexpensive to produce, and the assay format is simple and rapid. The thin film biosensor is adaptable to a wide variety of nucleic acid detection applications, including rapid diagnostic testing for infectious disease panels, antibiotic resistance panels, or allelic discrimination of specific genetic markers.
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Affiliation(s)
- R M Ostroff
- BioStar, Inc., 6655 Lookout Rd., Boulder, CO 80301, USA.
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15
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Abstract
Abstract
Background: We have developed a silicon-based biosensor that generates a visual signal in response to nucleic acid targets.
Methods: In this system, capture oligonucleotide probes are immobilized on the surface of the biosensor. Interaction of the capture probes with a complementary target and a biotinylated detector oligonucleotide allows initiation of formation of an organic thin film on the biosensor. Thin film formation is completed by enzymatic activity of peroxidase conjugated to an anti-biotin antibody. Peroxidase catalyzes deposition of an insoluble product onto the silicon surface, generating a uniform thin film. The increased thickness on the surface alters the perceived color of the biosensor through changes in the interference patterns of reflected light from the surface, causing a color change from gold to purple.
Results: The biosensor results may be evaluated by direct visual inspection or quantified by ellipsometry. Results are obtained in 25 min with a detection limit of 5 pmol/L (150 amol/sample). Selectivity of the biosensor is demonstrated by discrimination of single nucleotide mismatches. Multitarget arrays are also analyzed with the thin film biosensor, and the system is capable of detecting targets from human serum and urine.
Conclusions: The biosensor surface is inexpensive to produce, and the assay format is simple and rapid. The thin film biosensor is adaptable to a wide variety of nucleic acid detection applications, including rapid diagnostic testing for infectious disease panels, antibiotic resistance panels, or allelic discrimination of specific genetic markers.
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16
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Ostroff RM, Maul D, Bogart GR, Yang S, Christian J, Hopkins D, Clark D, Trotter B, Moddel G. Fixed polarizer ellipsometry for simple and sensitive detection of thin films generated by specific molecular interactions: applications in immunoassays and DNA sequence detection. Clin Chem 1998. [DOI: 10.1093/clinchem/44.9.2031] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Biological thin films may form on a surface by specific molecular interactions. The fixed polarizer ellipsometer (FPE) is a sensitive instrument that detects biological thin films either qualitatively or quantitatively. The design is simple and inexpensive. The assays are formatted on an optical surface, and the FPE detection is based on the phase shift of linearly polarized light after reflection through a thin film. We have constructed mathematical models of the FPE response to reflection through single-layer and two-layer films that agree closely with experimental data. Several biological assays have been measured with the FPE to demonstrate the application of this technology to clinical targets, including ultrasensitive immunoassays for hepatitis B surface antigen (0.1 ng/mL) and α-fetoprotein (0.01 ng/mL) and DNA hybridization (0.5 fmol/μL target probe). A clinical study for detection of group A streptococcus from patient throat swabs demonstrated the qualitative application of the FPE to infectious disease targets. The flexibility and sensitivity of the FPE makes this technology suitable for numerous target analytes and applications.
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Affiliation(s)
| | | | | | | | | | | | | | - Brian Trotter
- Department of Electrical and Computer Engineering, University of Colorado, Boulder, CO 80309-0425
| | - Garret Moddel
- Department of Electrical and Computer Engineering, University of Colorado, Boulder, CO 80309-0425
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17
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Ostroff RM, Maul D, Bogart GR, Yang S, Christian J, Hopkins D, Clark D, Trotter B, Moddel G. Fixed polarizer ellipsometry for simple and sensitive detection of thin films generated by specific molecular interactions: applications in immunoassays and DNA sequence detection. Clin Chem 1998; 44:2031-5. [PMID: 9733001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Biological thin films may form on a surface by specific molecular interactions. The fixed polarizer ellipsometer (FPE) is a sensitive instrument that detects biological thin films either qualitatively or quantitatively. The design is simple and inexpensive. The assays are formatted on an optical surface, and the FPE detection is based on the phase shift of linearly polarized light after reflection through a thin film. We have constructed mathematical models of the FPE response to reflection through single-layer and two-layer films that agree closely with experimental data. Several biological assays have been measured with the FPE to demonstrate the application of this technology to clinical targets, including ultrasensitive immunoassays for hepatitis B surface antigen (0.1 ng/mL) and alpha-fetoprotein (0.01 ng/ mL) and DNA hybridization (0.5 fmol/microL target probe). A clinical study for detection of group A streptococcus from patient throat swabs demonstrated the qualitative application of the FPE to infectious disease targets. The flexibility and sensitivity of the FPE makes this technology suitable for numerous target analytes and applications.
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18
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Affiliation(s)
- P A Supon
- Department of Pathology, Fitzsimons Army Medical Center, Aurora, CO, USA
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19
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Abstract
The Saccharomyces cerevisiae CDC7 gene encodes a protein kinase that functions in three aspects of DNA metabolism: replication, repair, and meiotic recombination. It is likely that these functions overlap and share common elements. The cell cycle dependence of Cdc7 associated DNA repair was examined by UV irradiating a wild type and hypomutable cdc7-7 strain throughout the cell cycle. Both the wild type strain and the cdc7-7 mutant stain delay entry into S phase by 40-60 min when exposed to UV mutagenesis. Cells in G1 are the most sensitive to lethal UV damage while cells in S phase sustain fewer lethal hits. The yield of mutants is greatest for the CDC7 wild type strain when S phase cells are mutagenized. This peak of induced mutagenesis is absent in the cdc7-7 strain. Cdc7 protein may be required for error-prone DNA repair or for translesion error-prone DNA replication and not for the checkpoints in G1 phase. Because Cdc28 protein kinase and Dbf4 protein, a Cdc7 kinase regulator, are also important for induced mutagenesis and the CDC7 promoter is not induced in response to DNA damage, Cdc7 protein kinase may be regulated post-translationally following DNA damage, in the same manner as it is regulated during the cell cycle.
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Affiliation(s)
- R M Ostroff
- Department of Biochemistry, Biophysics and Genetics, University of Colorado Health Sciences Center, Denver 80262, USA
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20
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Ostroff RM, Steaffens JW. Effect of specimen storage, antibiotics, and feminine hygiene products on the detection of group B Streptococcus by culture and the STREP B OIA test. Diagn Microbiol Infect Dis 1995; 22:253-9. [PMID: 8565413 DOI: 10.1016/0732-8893(95)00046-d] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Agar culture from vaginal swabs is the routine method for diagnosis of maternal Group B Streptococcus (GBS) colonization. Swab specimens are often transported to a clinical laboratory for processing. In these studies, specimen transport was simulated by inoculating swabs with GBS and storing them at selected temperatures and with or without transport medium. The recovery of viable GBS was assessed by agar culture. GBS antigen was detected immunologically with an Optical ImmunoAssay (OIA) method. Swabs that were stored with transport medium harbored viable but rapidly declining numbers of GBS. In contrast, a strong OIA signal was maintained. Recovery of viable GBS organisms declined more quickly when swabs were stored in the absence of transport medium, whereas detection of GBS antigen remained consistent. Both methods were tested for interference from either antibiotics or feminine hygiene products. These compounds inhibited the detection of GBS by culture but had no detrimental effect on the OIA result.
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21
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Hollingsworth RE, Ostroff RM, Klein MB, Niswander LA, Sclafani RA. Molecular genetic studies of the Cdc7 protein kinase and induced mutagenesis in yeast. Genetics 1992; 132:53-62. [PMID: 1398063 PMCID: PMC1205129 DOI: 10.1093/genetics/132.1.53] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The Saccharomyces cerevisiae CDC7 gene encodes a protein kinase that functions in DNA replication, repair, and meiotic recombination. The sequence of several temperature-sensitive (ts) cdc7 mutations was determined and correlated with protein kinase consensus domain structure. The positions of these ts alleles suggests some general principles for predicting ts protein kinase mutations. Pedigree segregation lag analysis demonstrated that all of the mutant proteins are less active or less stable than wild-type Cdc7p. Two new mutations were constructed, one by site-directed and the other by insertional mutagenesis. All of the cdc7 mutants were assayed for induced mutagenesis in response to mutagenic agents at the permissive temperature. Some cdc7 mutants were found to be hypomutable, while others are hypermutable. The differences in mutability are observed most clearly when log phase cells are used. Both hypo- and hypermutability are recessive to wild type. Cdc7p may participate in DNA repair by phosphorylating repair enzymes or by altering chromatin structure to allow accessibility to DNA lesions.
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Affiliation(s)
- R E Hollingsworth
- University of Colorado Health Sciences Center, Department of Biochemistry, Biophysics and Genetics, Denver 80262
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22
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Vasil ML, Krieg DP, Kuhns JS, Ogle JW, Shortridge VD, Ostroff RM, Vasil AI. Molecular analysis of hemolytic and phospholipase C activities of Pseudomonas cepacia. Infect Immun 1990; 58:4020-9. [PMID: 2254027 PMCID: PMC313771 DOI: 10.1128/iai.58.12.4020-4029.1990] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
By using a gene-specific fragment from the hemolytic phospholipase C (PLC) gene of Pseudomonas aeruginosa as a probe and data from Southern hybridizations under reduced stringency conditions, we cloned a 4.2-kb restriction fragment from a beta-hemolytic Pseudomonas cepacia strain which expressed hemolytic and PLC activities in Escherichia coli under the control of the lac promoter. It was found, by using a T7 phage promoter-directed expression system, that this DNA fragment carries at least two genes. One gene which shares significant DNA homology with both PLC genes from P. aeruginosa encodes a 72-kDa protein, while the other gene encodes a 22-kDa protein. When both genes on the 4.2-kb fragment were expressed from the T7 promoter in the same cell, hemolytic and PLC activities could be detected in the cell lysate. In contrast, when each individual gene was expressed in different cells or when lysates containing the translated products of each separate gene were mixed, neither hemolytic activity nor PLC activity could be detected. Clinical and environmental isolates of P. cepacia were examined for beta-hemolytic activity, PLC activity, sphingomyelinase activity, and reactivity in Southern hybridizations with a probe from P. cepacia which is specific for the larger gene which encodes the 72-kDa protein. There were considerable differences in the ability of the different strains to express hemolytic and PLC activities, and the results of Southern DNA-DNA hybridizations of the genomic DNAs of these strains revealed considerable differences in the probe-reactive fragments between high- and medium-stringency conditions as well as remarkable variation in size and number of probe-reactive fragments among different strains. Analysis of the genomic DNAs from hemolytic and nonhemolytic variants of an individual strain (PC-69) by agarose gel electrophoresis. Southern hybridization, and transverse alternating pulsed field gel electrophoresis suggests that the conversion of the hemolytic phenotype to the nonhemolytic phenotype is associated with either the loss of a large plasmid (greater than 200 kb) or a large deletion of the chromosome of P. cepacia PC-69.
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Affiliation(s)
- M L Vasil
- Department of Microbiology and Immunology, University of Colorado Health Sciences Center, Denver 80262
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23
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Abstract
Pseudomonas aeruginosa produces two secreted phospholipase C (PLC) enzymes. The expression of both PLCs is regulated by Pi. One of the PLCs is hemolytic, and one is nonhemolytic. Low-stringency hybridization studies suggested that the genes encoding these two PLCs shared DNA homology. This information was used to clone plcN, the gene encoding the 77-kilodalton nonhemolytic PLC, PLC-N. A fragment of plcN was used to mutate the chromosomal copy of plcN by the generation of a gene interruption mutation. This mutant produces 55% less total PLC activity than the wild type, confirming the successful cloning of plcN. plcN was sequenced and encodes a protein which is 40% identical to the hemolytic PLC (PLC-H). The majority of the homology lies within the NH2 two-thirds of the proteins, while the remaining third of the amino acid sequence of the two proteins shows very little homology. Both PLCs hydrolyze phosphatidylcholine; however, each enzyme has a distinct substrate specificity. PLC-H hydrolyzes sphingomyelin in addition to phosphatidylcholine, whereas PLC-N is active on phosphatidylserine as well as phosphatidylcholine. These studies suggest structure-function relationships between PLC activity and hemolysis.
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Affiliation(s)
- R M Ostroff
- Department of Microbiology and Immunology, University of Colorado Health Sciences Center, Denver 80262
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24
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Abstract
An insertion mutation constructed by gene replacement methods was used to map the gene corresponding to the hemolytic phospholipase C (plcS gene) in Pseudomonas aeruginosa PAO1 by R68.45-mediated conjugation. plcS mapped approximately at 67 min on the 75-min chromosomal map (B. W. Holloway, K. O'Hoy, and H. Matsumoto, p. 213-221, in S. J. O'Brien, ed., Genetic Maps 1987, vol. 4, 1987), between the markers pur-67 and pru-375 and considerably distal to the regulatory genes plcA and plcB, which are located at approximately 12 min.
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Affiliation(s)
- V Lindgren
- Department of Clinical Bacteriology, Danderyd Hospital, Sweden
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25
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Ostroff RM, Wretlind B, Vasil ML. Mutations in the hemolytic-phospholipase C operon result in decreased virulence of Pseudomonas aeruginosa PAO1 grown under phosphate-limiting conditions. Infect Immun 1989; 57:1369-73. [PMID: 2496027 PMCID: PMC313284 DOI: 10.1128/iai.57.5.1369-1373.1989] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The phospholipase C (PLC) operon of Pseudomonas aeruginosa consists of plcS, which encodes a heat-labile secreted hemolysin, and two in-phase, overlapping genes, plcR1 and plcR2, which may encode Pi-regulatory genes. A 2.8-kilobase-pair deletion mutation in this operon was constructed, and a tetracycline resistance (Tcr) cartridge replaced the deleted sequences. A deletion mutant of strain PAO1 was obtained through recombination between the flanking regions of the mutated cloned PLC operon and the homologous chromosomal regions. The deletion of the chromosomal PLC operon and its replacement by the Tcr cartridge was confirmed by Southern hybridization. The deletion strain, PLC SR, is nonhemolytic. However, it retains PLC activity when measured on a synthetic substrate. A second mutant strain, PLC R, contains a deletion in the plcR genes. This mutant is more hemolytic and produces more enzymatic activity than PAO1. The virulence of both of these mutants was compared with that of PAO1 in the mouse burn model of infection. When mice were infected with cultures grown in a high-Pi medium, there was a 10-fold increase in the 50% lethal dose of the mutants compared with PAO1. In contrast, when the inoculum originated from low-Pi cultures, there was a 200- to 10,000-fold increase in the 50% lethal dose of the mutants over PAO1.
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Affiliation(s)
- R M Ostroff
- Department of Microbiology and Immunology, University of Colorado Health Sciences Center, Denver 80262
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Ostroff RM, Vasil ML. Identification of a new phospholipase C activity by analysis of an insertional mutation in the hemolytic phospholipase C structural gene of Pseudomonas aeruginosa. J Bacteriol 1987; 169:4597-601. [PMID: 2820937 PMCID: PMC213827 DOI: 10.1128/jb.169.10.4597-4601.1987] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The phospholipase C (PLC) gene of Pseudomonas aeruginosa encodes a heat-labile secreted hemolysin which is part of a Pi-regulated operon. The structural gene for PLC, plcS, was mutated in vitro by insertion of a tetracycline resistance gene cartridge. Gene replacement techniques were used to introduce the mutated plcS gene into the P. aeruginosa chromosome in place of the wild-type gene. The precise replacement of wild-type sequences by mutant sequences was confirmed by Southern hybridization. The mutant strain, designated PLC S, is nonhemolytic and lacks a 78-kilodalton protein corresponding to the size of the wild-type PLC. However, there is an additional phospholipase activity present in PLC S capable of hydrolyzing p-nitrophenylphosphorylcholine, a synthetic PLC substrate, and phosphatidylcholine. This enzymatic activity is not a result of a truncated product produced from the mutated plcS gene. The phospholipase activity of PLC S was identified as a nonhemolytic PLC.
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Affiliation(s)
- R M Ostroff
- Department of Microbiology and Immunology, University of Colorado Health Sciences Center, Denver 80262
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