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Gut M, Dreier B, Furler S, Sobek J, Plückthun A, Holland JP. Designed ankyrin repeat proteins for detecting prostate-specific antigen expression in vivo. RSC Chem Biol 2023; 4:494-505. [PMID: 37415866 PMCID: PMC10320840 DOI: 10.1039/d3cb00010a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 05/16/2023] [Indexed: 07/08/2023] Open
Abstract
Late-stage prostate cancer often acquires resistance to conventional chemotherapies and transforms into a hormone-refractory, drug-resistant, and non-curative disease. Developing non-invasive tools to detect the biochemical changes that correlate with drug efficacy and reveal the onset of drug resistance would have important ramifications in managing the treatment regimen for individual patients. Here, we report the selection of new Designed Ankyrin Repeat Proteins (DARPins) that show high affinity toward prostate-specific antigen (PSA), a biomarker used in clinical monitoring of prostate cancer. Ribosome display and in vitro screening tools were used to select PSA-binding DARPins based on their binding affinity, selectivity, and chemical constitution. Surface plasmon resonance measurements demonstrated that the four lead candidates bind to PSA with nanomolar affinity. DARPins were site-specifically functionalised at a unique C-terminal cysteine with a hexadentate aza-nonamacrocyclic chelate (NODAGA) for subsequent radiolabelling with the positron-emitting radionuclide 68Ga. [68Ga]GaNODAGA-DARPins showed high stability toward transchelation and were stable in human serum for >2 h. Radioactive binding assays using streptavidin-loaded magnetic beads confirmed that the functionalisation and radiolabelling did not compromise the specificity of [68Ga]GaNODAGA-DARPins toward PSA. Biodistribution experiments in athymic nude mice bearing subcutaneous prostate cancer xenografts derived from the LNCaP cell line revealed that three of the four [68Ga]GaNODAGA-DARPins displayed specific tumour-binding in vivo. For DARPin-6, tumour-uptake in the normal group reached 4.16 ± 0.58% ID g-1 (n = 3; 2 h post-administration) and was reduced by ∼50% by competitive binding with a low molar activity formulation (blocking group: 2.47 ± 0.42% ID g-1; n = 3; P value = 0.018). Collectively, the experimental results support the future development of new PSA-specific imaging agents for potential use in monitoring the efficacy of androgen receptor (AR)-targeted therapies.
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Affiliation(s)
- Melanie Gut
- University of Zurich, Department of Chemistry Winterthurerstrasse 190 CH-8057, Zurich Switzerland https://www.hollandlab.org https://twitter.com/HollandLab_ +41-44-63-53990
| | - Birgit Dreier
- University of Zurich, Department of Biochemistry Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Sven Furler
- University of Zurich, Department of Biochemistry Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Jens Sobek
- Functional Genomics Center Zurich, Eidgenössische Technische Hochschule (ETH) Zurich and University of Zurich Zurich Switzerland
| | - Andreas Plückthun
- University of Zurich, Department of Biochemistry Winterthurerstrasse 190 8057 Zurich Switzerland
| | - Jason P Holland
- University of Zurich, Department of Chemistry Winterthurerstrasse 190 CH-8057, Zurich Switzerland https://www.hollandlab.org https://twitter.com/HollandLab_ +41-44-63-53990
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2
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Sandúa A, Sanmamed MF, Rodríguez M, Ancizu-Marckert J, Gúrpide A, Perez-Gracia JL, Alegre E, González Á. PSA reactivity in extracellular microvesicles to commercial immunoassays. Clin Chim Acta 2023; 543:117303. [PMID: 36948237 DOI: 10.1016/j.cca.2023.117303] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 03/24/2023]
Abstract
AIMS Characterization of PSA in extracellular microvesicles (EVs) and its reactivity to commercial methods. MATERIALS AND METHODS EVs derived from serum of 47 prostate cancer (PCa) patients, 27 benign prostatic hyperplasia (BPH) patients and 42 healthy controls were analyzed. EVs isolation and quantification of PSA immunoreactive to total (ev-T-PSA) or free (ev-F-PSA) PSA immunoassays, were performed using commercial assays. PSA in CD81+ or CD63+ EVs was determined directly in serum by an immunocapture-ELISA (IC-ELISA). RESULTS Ev-T-PSA immunoreactive to Elecsys assay was detected in all samples. Median T-PSA ev/srm ratio was 2.20% (Q1-Q3: 0.80-4.00%), although in some samples this ratio reached 59%. T-PSA ev/srm ratio was higher in those samples with serum T-PSA below 4 µg/L than in those exceeding that cut-off (p<0.001). T-PSA ev/srm ratio was lower in PCa patients compared to healthy controls and BPH patients (p<0.001). Elecsys immunoassays detected higher concentrations of ev-T-PSA and ev-F-PSA than Immulite (p<0.001). PSA was detected by IC-ELISA more intensely in CD81+ EVs than in CD63+ EVs, and ev-T-PSA correlated with PSA+CD63+ (p<0.001) but not with PSA+CD81+. CONCLUSION EVs-bound PSA is another form of circulating PSA whose measurement could be easily performed in clinical laboratories by automated immunoassays.
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Affiliation(s)
- Amaia Sandúa
- Service of Biochemistry. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain.
| | - Miguel F Sanmamed
- Oncology Department. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Calle Irunlarrea 3, 31008, Pamplona, Spain
| | - María Rodríguez
- Oncology Department. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Calle Irunlarrea 3, 31008, Pamplona, Spain
| | - Javier Ancizu-Marckert
- Urology Department. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain
| | - Alfonso Gúrpide
- Oncology Department. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain
| | - José L Perez-Gracia
- Oncology Department. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Calle Irunlarrea 3, 31008, Pamplona, Spain
| | - Estibaliz Alegre
- Service of Biochemistry. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Calle Irunlarrea 3, 31008, Pamplona, Spain
| | - Álvaro González
- Service of Biochemistry. Clínica Universidad de Navarra, Av. Pío XII 36, 31008, Pamplona, Spain; IdiSNA, Navarra Institute for Health Research, Calle Irunlarrea 3, 31008, Pamplona, Spain
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3
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Dou Y, Li Z, Su J, Song S. A Portable Biosensor Based on Au Nanoflower Interface Combined with Electrochemical Immunochromatography for POC Detection of Prostate-Specific Antigen. BIOSENSORS 2022; 12:bios12050259. [PMID: 35624559 PMCID: PMC9138250 DOI: 10.3390/bios12050259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/18/2022] [Accepted: 04/18/2022] [Indexed: 05/23/2023]
Abstract
Serum prostate-specific antigen (PSA) is a widely used for the detection of prostate cancer and is considered the most reliable biomarker. However, the currently reported detection methods cannot achieve rapid monitoring. Here, we report a novel electrochemical immunochromatography (EIC) system for clinically accurate PSA detection. First, we constructed a carbon interface modified with gold nanoflowers (Au NFs) based on screen-printed carbon electrodes (SPCE), which acted as nanostructures with larger specific surface area that increased the number of PSA capture antibodies and can further improve detection signal-to-noise (S/N) ratio. Then, we fabricated detection chips by combining the SPCE/Au NFs with EIC. Under optimized conditions, the proposed biosensor exhibits high accuracy, taking only 15 minutes to complete detection. By measuring the levels of PSA in clinical blood samples, the biosensor can successfully discriminate clinically diagnosed prostate cancer patients from healthy controls.
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Affiliation(s)
- Yanzhi Dou
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; (Y.D.); (Z.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhenhua Li
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; (Y.D.); (Z.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Su
- State Key Laboratory of Oncogenes and Related Genes, Institute for Personalized Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China;
| | - Shiping Song
- Division of Physical Biology, CAS Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China; (Y.D.); (Z.L.)
- The Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
- Correspondence:
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4
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Feng D, Su J, Xu Y, He G, Wang C, Wang X, Pan T, Ding X, Mi X. DNA tetrahedron-mediated immune-sandwich assay for rapid and sensitive detection of PSA through a microfluidic electrochemical detection system. MICROSYSTEMS & NANOENGINEERING 2021; 7:33. [PMID: 34567747 PMCID: PMC8433179 DOI: 10.1038/s41378-021-00258-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 02/25/2021] [Accepted: 03/08/2021] [Indexed: 05/12/2023]
Abstract
Prostate-specific antigen (PSA) is the most widely used biomarker for the early diagnosis of prostate cancer. Existing methods for PSA detection are burdened with some limitations and require improvement. Herein, we developed a novel microfluidic-electrochemical (μFEC) detection system for PSA detection. First, we constructed an electrochemical biosensor based on screen-printed electrodes (SPEs) with modification of gold nanoflowers (Au NFs) and DNA tetrahedron structural probes (TSPs), which showed great detection performance. Second, we fabricated microfluidic chips by DNA TSP-Au NF-modified SPEs and a PDMS layer with designed dense meandering microchannels. Finally, the μFEC detection system was achieved based on microfluidic chips integrated with the liquid automatic conveying unit and electrochemical detection platform. The μFEC system we developed acquired great detection performance for PSA detection in PBS solution. For PSA assays in spiked serum samples of the μFEC system, we obtained a linear dynamic range of 1-100 ng/mL with a limit of detection of 0.2 ng/mL and a total reaction time <25 min. Real serum samples of prostate cancer patients presented a strong correlation between the "gold-standard" chemiluminescence assays and the μFEC system. In terms of operation procedure, cost, and reaction time, our method was superior to the current methods for PSA detection and shows great potential for practical clinical application in the future.
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Affiliation(s)
- Dezhi Feng
- Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Jing Su
- State Key Laboratory of Oncogenes and Related Genes, Institute for Personalized Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, 200030 Shanghai, China
| | - Yi Xu
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
| | - Guifang He
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
- School of Life Sciences, Shanghai University, 200444 Shanghai, China
| | - Chenguang Wang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
| | - Xiao Wang
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
- School of Life Sciences, Shanghai University, 200444 Shanghai, China
| | - Tingrui Pan
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Science, 518055 Shenzhen, China
| | - Xianting Ding
- State Key Laboratory of Oncogenes and Related Genes, Institute for Personalized Medicine, School of Biomedical Engineering, Shanghai Jiao Tong University, 200030 Shanghai, China
| | - Xianqiang Mi
- Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 200050 Shanghai, China
- Shanghai Advanced Research Institute, Chinese Academy of Sciences, 201210 Shanghai, China
- University of Chinese Academy of Sciences, 100049 Beijing, China
- CAS Center for Excellence in Superconducting Electronics, (CENSE), 200050 Shanghai, China
- Key Laboratory of Systems Health Science of Zhejiang Province, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 310024 Hangzhou, China
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5
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Chen YT, Tuan LP, Chen HW, Wei IA, Chou MY, Chen HM, Tyan YC, Chen SF. Quantitative Analysis of Prostate Specific Antigen Isoforms Using Immunoprecipitation and Stable Isotope Labeling Mass Spectrometry. Anal Chem 2014; 87:545-53. [DOI: 10.1021/ac5033066] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yi-Ting Chen
- Department
of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 333, Taiwan
- Molecular
Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan
| | - Li-Ping Tuan
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
| | - Hsiao-Wei Chen
- Molecular
Medicine Research Center, Chang Gung University, Taoyuan 333, Taiwan
| | - I-An Wei
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
| | - Min-Yuan Chou
- Biomedical
Technology and Devices Research Laboratories, Industrial Technology Research Institute, Chutung 31040, Taiwan
| | - Han-Min Chen
- Department
of Life Science, Catholic Fu-Jen University, Taipei 24205, Taiwan
| | - Yu-Chang Tyan
- Department
of Medical Imaging and Radiological Sciences, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Sung-Fang Chen
- Department
of Chemistry, National Taiwan Normal University, Taipei 11677 Taiwan
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6
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Suaifan GARY, Esseghaier C, Ng A, Zourob M. Ultra-rapid colorimetric assay for protease detection using magnetic nanoparticle-based biosensors. Analyst 2013; 138:3735-9. [DOI: 10.1039/c3an36881e] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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7
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Izawa JI, Klotz L, Siemens DR, Kassouf W, So A, Jordan J, Chetner M, Iansavichene AE. Prostate cancer screening: Canadian guidelines 2011. Can Urol Assoc J 2011; 5:235-40. [PMID: 21801679 DOI: 10.5489/cuaj.11134] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Jonathan I Izawa
- Departments of Surgery & Oncology, Divisions of Urology & Surgical Oncology, The Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON
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8
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Yousef GM, Diamandis EP. The human kallikrein gene family: new biomarkers for ovarian cancer. Cancer Treat Res 2010; 149:165-87. [PMID: 19763436 DOI: 10.1007/978-0-387-98094-2_8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- George M Yousef
- Mount Sinai Hospital, University Health Network and Toronto Medical Laboratories, University of Toronto, Toronto, ON, Canada
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9
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Goettig P, Magdolen V, Brandstetter H. Natural and synthetic inhibitors of kallikrein-related peptidases (KLKs). Biochimie 2010; 92:1546-67. [PMID: 20615447 PMCID: PMC3014083 DOI: 10.1016/j.biochi.2010.06.022] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/29/2010] [Indexed: 01/21/2023]
Abstract
Including the true tissue kallikrein KLK1, kallikrein-related peptidases (KLKs) represent a family of fifteen mammalian serine proteases. While the physiological roles of several KLKs have been at least partially elucidated, their activation and regulation remain largely unclear. This obscurity may be related to the fact that a given KLK fulfills many different tasks in diverse fetal and adult tissues, and consequently, the timescale of some of their physiological actions varies significantly. To date, a variety of endogenous inhibitors that target distinct KLKs have been identified. Among them are the attenuating Zn(2+) ions, active site-directed proteinaceous inhibitors, such as serpins and the Kazal-type inhibitors, or the huge, unspecific compartment forming α(2)-macroglobulin. Failure of these inhibitory systems can lead to certain pathophysiological conditions. One of the most prominent examples is the Netherton syndrome, which is caused by dysfunctional domains of the Kazal-type inhibitor LEKTI-1 which fail to appropriately regulate KLKs in the skin. Small synthetic inhibitory compounds and natural polypeptidic exogenous inhibitors have been widely employed to characterize the activity and substrate specificity of KLKs and to further investigate their structures and biophysical properties. Overall, this knowledge leads not only to a better understanding of the physiological tasks of KLKs, but is also a strong fundament for the synthesis of small compound drugs and engineered biomolecules for pharmaceutical approaches. In several types of cancer, KLKs have been found to be overexpressed, which makes them clinically relevant biomarkers for prognosis and monitoring. Thus, down regulation of excessive KLK activity in cancer and in skin diseases by small inhibitor compounds may represent attractive therapeutical approaches.
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Affiliation(s)
- Peter Goettig
- Division of Structural Biology, Department of Molecular Biology, University of Salzburg, Billrothstrasse 11, 5020 Salzburg, Austria.
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10
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Zhao N, He Y, Mao X, Sun Y, Zhang X, Li CZ, Lin Y, Liu G. Electrochemical assay of active prostate-specific antigen (PSA) using ferrocene-functionalized peptide probes. Electrochem commun 2010. [DOI: 10.1016/j.elecom.2010.01.022] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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11
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Patanè S. Prostate-specific antigen kallikrein and the heart. World J Cardiol 2009; 1:23-5. [PMID: 21160572 PMCID: PMC2999037 DOI: 10.4330/wjc.v1.i1.23] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 12/27/2009] [Accepted: 12/28/2009] [Indexed: 02/06/2023] Open
Abstract
Currently, there is growing interest regarding prostate-specific antigen (PSA) and the cardiovascular system. Increased PSA serum levels have been reported after prolonged cardiopulmonary resuscitation, cardiac surgery, extracorporeal cardiopulmonary bypass, acute myocardial infarction (AMI) and coronary artery stenting. The possible role of PSA in cardiac events has been questioned due to the finding of PSA decrease during AMI and by the correlation of variation in PSA levels with coronary lesions and occurrence of major adverse cardiac events. Complexed PSA forms and uncomplexed PSA forms are observed in the bloodstream but the increasing formation of irreversible bound PSA seems to be a crucial finding during AMI. Large studies need to be carried out to confirm these preliminary results and to elucidate unclear aspects. These findings present many potential directions for future research including the role of uncomplexed forms of PSA, the possible distribution of PSA in the heart, the relative expression levels in heart disease states, the mode of expression regulation and other potential specific substrates. The journey of PSA investigation could be longer than initially expected.
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Affiliation(s)
- Salvatore Patanè
- Salvatore Patanè, Cardiology Unit, New Cutroni Zodda Hospital, Barcellona P.d.G(Me), Provincial Health Authority of Messina, 98051 Barcellona Pozzo di Gotto(Me), Italy
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12
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Patanè S, Marte F, Sturiale M. Prostate-specific antigen kallikrein complexes and acute myocardial infarction. Int J Cardiol 2009; 145:227-228. [PMID: 19615765 DOI: 10.1016/j.ijcard.2009.06.044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 06/26/2009] [Indexed: 10/20/2022]
Abstract
Recently, attention has focused on prostate-specific antigen kallikrein and the cardiovascular system. The finding of diminished PSA during acute myocardial infarction and the correlation of variation of PSA with coronary lesions and occurrence of major adverse cardiac events have opened a possible new intriguing scenario. As with many stories in biology, the tale of PSA can be more complex than was first appreciated. In the bloodstream, the proteolytic activity of PSA is inhibited by the formation of irreversible complexes with serum protease inhibitors and other acute-phase proteins. We noticed that the formation of irreversible PSA complexes (reflected by the increased bound PSA) has significant correlation with high-sensitivity C-reactive protein (hsCRP) and that seems to play a crucial role in the adverse event prevention.
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Affiliation(s)
- Salvatore Patanè
- Cardiologia Nuovo Presidio Ospedaliero Cutroni Zodda-Barcellona P.d.G(Me) AUSL5 Messina, Italy. patane-@libero.it
| | - Filippo Marte
- Cardiologia Nuovo Presidio Ospedaliero Cutroni Zodda-Barcellona P.d.G(Me) AUSL5 Messina, Italy
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13
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Verratti V, Di Giulio C, Di Francesco S, Berardinelli F, Pellicciotta M, Gidaro S, Zezza A, Tenaglia R. Chronic Hypoxia, Physical Exercise and PSA: Correlation during High-Altitude Trekking (2004 K2 Expedition). Urol Int 2007; 78:305-7. [PMID: 17495486 DOI: 10.1159/000100832] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 05/04/2006] [Indexed: 11/19/2022]
Abstract
The aim of the present study was to identify the effects of physical exercise on PSA serum levels and the diagnostic validity of PSA in the screening of prostate cancer in subjects undergoing physical exercise during chronic hypoxia. The study was performed during trekking between 3,200 and 5,600 meters of altitude on K2 mountain for 26 days. Mean serum PSA values before and after exposure did not show significant difference due to physical exercise. These data indicate that physical exercise or mountain hypoxia do not affect the diagnostic validity of PSA.
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Affiliation(s)
- Vittore Verratti
- Clinica Urologica, Dipartimento di Scienze dell'Invecchiamento, Università 'G. d'Annunzio', Chieti, Italia.
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14
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Acevedo B, Perera Y, Torres E, Pentón D, Ayala M, Gavilondo J. Fast and novel purification method to obtain the prostate specific antigen (PSA) from human seminal plasma. Prostate 2006; 66:1029-36. [PMID: 16598740 DOI: 10.1002/pros.20267] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Prostate specific antigen (PSA) is a relevant antigen in diagnosis; follow-up, and therapeutic approaches for fighting the prostate cancer. Several methods have been published previously to obtain a high purity preparation of PSA. In general, these methods are expensive, time-consuming, laborious, and in some cases produce low yields. METHODS Based on a panel of 7 anti-PSA Mab's we carried on binding and elution experiments of PSA antigen in 96-well plates. The selected Mab were immobilized in a Sepharose CL-4B activated matrix with the purpose of purify PSA from human seminal fluid. In order to optimize the purification procedure, we test several washing and elution conditions (chaotropic agents, high ionic strength solution, and extreme pH). RESULTS We selected a high ionic strength solution (2 M MgCl2) as elution condition, and a previous washing step with a mix of two ionic solutions (2.5 M NaCl pH 8/1 M MgCl2 pH 5.5) in order to purify PSA. Using such conditions we obtained a PSA preparation with 90% of purity and 50% of recovery. CONCLUSION In this article, we report a simple, quickly, and non-expensive procedure to obtain free-PSA from human seminal plasma at high purity levels.
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Affiliation(s)
- Boris Acevedo
- Center for Genetic Engineering and Biotechnology, Havana, Cuba.
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15
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Yousef GM, Obiezu CV, Luo LY, Magklara A, Borgoño CA, Kishi T, Memari N, Michael LP, Sidiropoulos M, Kurlender L, Economopolou K, Kapadia C, Komatsu N, Petraki C, Elliott M, Scorilas A, Katsaros D, Levesque MA, Diamandis EP. Human Tissue Kallikreins: From Gene Structure to Function and Clinical Applications. Adv Clin Chem 2005; 39:11-79. [PMID: 16013667 DOI: 10.1016/s0065-2423(04)39002-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- George M Yousef
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5G 1X5, Canada
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16
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Väisänen V, Eriksson S, Ivaska KK, Lilja H, Nurmi M, Pettersson K. Development of sensitive immunoassays for free and total human glandular kallikrein 2. Clin Chem 2004; 50:1607-17. [PMID: 15247158 DOI: 10.1373/clinchem.2004.035253] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Free and total human kallikrein 2 (hK2) might improve the discrimination between prostate cancer and benign prostatic hyperplasia. Concentrations of hK2 are 100-fold lower than concentrations of prostate-specific antigen (PSA); therefore, an hK2 assay must have a low detection limit and good specificity. METHODS PSA- and hK2-specific monoclonal antibodies were used in solid-phase, two-site immunofluorometric assays to detect free and total hK2. The total hK2 assay used PSA-specific antibodies to block nonspecific signal. The capture antibody of the free hK2 assay did not cross-react with PSA. To determine the hK2 concentrations in the male bloodstream, total hK2 was measured in a control group consisting of 426 noncharacterized serum samples. Free and total hK2 were measured in plasma from 103 patients with confirmed prostate cancer. RESULTS All 426 males in the control group had a total hK2 concentration above the detection limit of 0.0008 microg/L. The median total hK2 concentration was 0.022 microg/L (range, 0.0015-0.37 microg/L). hK2 concentrations were 0.1-58% of total PSA (median, 3.6%). hK2 concentrations were similar in men 41-50 and 51-60 years of age. The ratio of hK2 to PSA steadily decreased from 5-30% at PSA <1 microg/L to 1-2% at higher PSA concentrations. In 103 patients with prostate cancer, the median hK2 concentration in plasma was 0.079 microg/L (range, 0.0015-16.2 microg/L). The median free hK2 concentration was 0.070 (range, 0.005-12.2) microg/L. The proportion of free to total hK2 varied from 17% to 131% (mean, 85%). CONCLUSIONS The wide variation in the free-to-total hK2 ratio suggests that hK2 in blood plasma is not consistently in the free, noncomplexed form in patients with prostate cancer. The new assay is sufficiently sensitive to be used to study the diagnostic accuracies of free and total hK2 for prostate cancer.
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Affiliation(s)
- Ville Väisänen
- University of Turku, Department of Biotechnology, Finland.
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17
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Yousef GM, Kapadia C, Polymeris ME, Borgono C, Hutchinson S, Wasney GA, Soosaipillai A, Diamandis EP. The human kallikrein protein 5 (hK5) is enzymatically active, glycosylated and forms complexes with two protease inhibitors in ovarian cancer fluids. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1628:88-96. [PMID: 12890555 DOI: 10.1016/s0167-4781(03)00116-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The kallikrein family is a group of 15 serine protease genes clustered on chromosome 19q13.4. Binding of kallikreins to protease inhibitors is an important mechanism for regulating their enzymatic activity and may have potential clinical applications. Human kallikrein gene 5 (KLK5) is a member of this family and encodes for a secreted serine protease (hK5). This kallikrein was shown to be differentially expressed at the mRNA and protein levels in diverse malignancies. Our objective was to study the enzymatic activity and the interaction of recombinant hK5 protein with protease inhibitors. Recombinant hK5 protein was produced in yeast and mammalian expression systems and purified by chromatography. HPLC fractionation, followed by ELISA-type assays, immunoblotting and radiolabeling experiments were performed to detect the possible interactions between hK5 and proteinase inhibitors in serum. Enzymatic deglycosylation was performed to examine the glycosylation pattern of the protein. The enzymatic activity of hK5 was tested using trypsin and chymotrypsin-specific synthetic fluorogenic substrates. In serum and ascites fluid, in addition to the free ( approximately 40 kDa) form, hK5 forms complexes with alpha(1)-antitrypsin and alpha(2)-macroglobulin. These complexes were detected by hybrid ELISA-type assays using hK5-specific coating antibodies and inhibitor detection antibodies. The ability of hK5 to bind to these inhibitors was further verified in vitro. Spiking of serum samples with 125I-labeled hK5 results in the distribution of the protein in two higher molecular mass (bound) forms, in addition to the unbound form. The hK5 mature enzyme is active and shows trypsin, but not chymotrypsin-like, activity. The pro-form of hK5 is not active. Recombinant hK5 shows a higher than predicted molecular mass due to glycosylation. hK5 is partially complexed with alpha(1)-antitrypsin and alpha(2)-macroglobulin in serum and ascites fluid of ovarian cancer patients. The recombinant protein is glycosylated and its mature form shows trypsin-like activity.
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Affiliation(s)
- George M Yousef
- Department of Pathology and Laboratory Medicine, Division of Clinical Biochemistry, Mount Sinai Hospital, 600 University Avenue, M5G 1X5, Toronto, ON, Canada
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18
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Acevedo B, Perera Y, Ruiz M, Rojas G, Benítez J, Ayala M, Gavilondo J. Development and validation of a quantitative ELISA for the measurement of PSA concentration. Clin Chim Acta 2002; 317:55-63. [PMID: 11814458 DOI: 10.1016/s0009-8981(01)00749-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Prostate-specific antigen (PSA) has been used for the diagnosis and follow up of prostate cancer (PCa). METHODS Mouse monoclonal antibodies (MAbs) were generated against human prostate-specific antigen (PSA) for the development of a sensitive total PSA (t-PSA) assay. Two MAbs, denoted CB-PSA.4 and CB-PSA.9, with affinities of 3.7 x 10(9) and 4.7 x 10(10) l/mol, respectively, were used to develop an enzyme-linked immunosorbent assay (ELISA) for quantifying serum t-PSA concentration. RESULTS The detection limit (DL) of the assay was 0.1 microg/l (n=20, mean of "zero" standard+3S.D.), and the recovery of t-PSA was 96-103%. The within-run and between-day coefficients of variation (CV) ranged from 2.1% to 3.2%, and from 2.8% to 6.3% for PSA concentrations of 10 and 1 microg/l, respectively. The equimolar detection of t-PSA and free-PSA was demonstrated by two different methods, one consisted in the comparative evaluation of a sera panel (n=9) with our enzyme-linked immunosorbent assay (ELISA) and four commercial total PSA assays and the concordance with CIS bio total PSA assay. The assay had a linear range of 0.12 to 25 microg/l. CONCLUSIONS The analytical performance characteristics of our PSA ELISA suggest that it will provide clinically useful PSA results, particularly when diagnostic algorithms are used.
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Affiliation(s)
- Boris Acevedo
- Recombinant Antibodies Laboratories, Pharmaceutical Division, Center for Genetic Engineering and Biotechnology, Ave 31 and 58, Cubanacán, P.O. Box 6162, 10600, Havana, Cuba.
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19
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Sinha AA, Jamuar MP, Wilson MJ, Rozhin J, Sloane BF. Plasma membrane association of cathepsin B in human prostate cancer: biochemical and immunogold electron microscopic analysis. Prostate 2001; 49:172-84. [PMID: 11746262 DOI: 10.1002/pros.1132] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Cathepsin B (CB), a cysteine protease, is usually found in perinuclear lysosomes of epithelial cells of normal organs and non-malignant tumors, but is associated with the plasma membranes of many solid organ malignant tumors. Plasma membrane localized CB facilitates degradation of extracellular matrix proteins and progression of tumor cells from one biological compartment to another. The activities of CB and its subcellular distribution have not been investigated in malignant prostate. Our objective was to examine the subcellular distribution of CB by determining the activities of CB in lysosome and plasma membrane/endosome subcellular fractions and its subcellular localization by immunogold electron microscopy. METHODS Prostate tissue pieces obtained immediately after prostatectomy were homogenized and fractionated into subcellular components for determining biochemical activities of CB and cysteine protease inhibitors (CPIs). Distribution of CB was compared with that of prostate specific antigen (PSA, a serine protease), which is abundant in secretory vesicles and granules of normal prostate, benign prostatic hyperplasia (BPH) and malignant prostate cells. Localization of CB was investigated in resin embedded lysosomes and plasma membrane/endosome subcellular fractions and in prostate tissue sections by immunogold electron microscopy. RESULTS We have demonstrated the specificity of CB activity in human prostate homogenates by using a variety of inhibitors in our assay. We did not find any difference in the specific activity of CB based on protein or DNA content in homogenates of malignant prostate (Gleason histologic scores 5-7) and BPH (no histological evidence of cancer) whether it was measured by chromogenic or fluorogenic peptide substrate assay techniques. We found significantly higher activities of CB in the plasma membrane/endosome fractions of malignant prostate than in BPH. In contrast, CPI activity was increased relative to CB activity in plasma membrane/endosome fraction of BPH versus prostate cancer. Our data indicated a shift in the balance of enzyme to inhibitor that would favor increased activities of CB in prostate cancer. The immunogold microscopic study showed specific localization of CB in plasma membrane. They also showed localization of CB in lysosomes that were often adjacent to luminal and/or basal surfaces of malignant cells in contrast to the usual perinuclear distribution of lysosomes in hyperplastic prostate glands. PSA was localized in secretory granules and vesicles, including the plasma membranes and secretory blebs in malignant prostate cells. Occasional PSA positive secretory vesicles or membrane profiles were seen in the plasma membrane/endosomal and lysosomal fractions. CONCLUSIONS The increased activity of CB in plasma membrane/endosomal fractions is associated with malignant prostate and not with BPH or normal prostate. Morphologic distribution CB is associated with the plasma membranes or lysosomes adjacent to apical and basal cell surfaces. This distribution is characteristic feature prostate cancer cells, but not in BPH or normal prostate cells. Subcellular distribution of PSA occurs in secretory vesicles and granules of the cytoplasm, but not in lysosomes. Our biochemical and morphological data could be used to distinguish malignant prostates from non-malignant tumors.
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Affiliation(s)
- A A Sinha
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, USA.
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20
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Heuzé-Vourc'h N, Leblond V, Olayat S, Gauthier F, Courty Y. Characterization of PSA-RP2, a protein related to prostate-specific antigen and encoded by alternative hKLK3 transcripts. EUROPEAN JOURNAL OF BIOCHEMISTRY 2001; 268:4408-13. [PMID: 11502200 DOI: 10.1046/j.1432-1327.2001.02367.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Despite the wide use of prostate-specific antigen (PSA) as a marker of prostate cancer, analysis of its gene products has not yet been completed. The structure of two alternative mRNAs (0.9 and 1.65 kb) of the hKLK3 gene that retain the third intron is reported here. These partially spliced transcripts were detected by hybridization or RT-PCR in normal prostate tissue, benign prostate hyperplasia (BPH) and cancerous prostate tissues, and also in the prostate LNCaP cell line. Insertion of the unspliced intron creates an in-frame stop codon and results in a truncated prepro PSA variant of 180 amino-acid residues. This novel variant, designated PSA-RP2, has an alternate C-terminal tail and lacks the serine residue essential for the catalytic activity of PSA. Prepro PSA-RP2 was transiently produced in COS-7 cells and detected in the spent medium using an anti-PSA serum. Secreted PSA-RP2 was glycosylated with an apparent molecular mass of 25 kDa. Our findings suggest that PSA-RP2 contributes to the molecular heterogeneity of free-PSA in the serum of patients with benign or malignant prostate tumors.
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Affiliation(s)
- N Heuzé-Vourc'h
- Laboratoire d'Enzymologie et Chimie des Protéines, EMI-U 0010, Université F. Rabelais, Tours, France
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Finlay JA, Day JR, Evans CL, Carlson R, Kuus-Reichel K, Millar LS, Mikolajczyk SD, Goodmanson M, Klee GG, Rittenhouse HG. Development of a Dual Monoclonal Antibody Immunoassay for Total Human Kallikrein 2. Clin Chem 2001. [DOI: 10.1093/clinchem/47.7.1218] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Background: Human kallikrein 2 (hK2) shares 80% sequence identity with prostate-specific antigen (PSA). Because both hK2 and hK2-α1-antichymotrypsin (hK2-ACT) complexes have been identified in patient sera, we devised an immunoassay for total hK2 [(thK2); hK2 and hK2-ACT] and evaluated it in healthy subjects and patients with prostate disease.
Methods: We developed monoclonal antibodies (mAbs) with high specificity for hK2 and hK2-ACT and minimal cross-reactivity to PSA. Using these mAbs, a sandwich assay was developed and its specificity for forms of hK2 was assessed. Serum samples (n = 1035) from healthy volunteers, patients with increased PSA, and men who had undergone radical prostatectomy were assayed for thK2. We also measured thK2 in samples before and after storage under common laboratory conditions.
Results: The minimum detectable concentration in the thK2 assay was 0.008 μg/L, and PSA cross-reactivity was <0.001%. The assay detected prohK2 and three different hK2–serum protease complexes. The median serum concentration of thK2 in control samples (0.013 μg/L) was significantly lower than the median in samples from patients with increased PSA concentrations (0.085 μg/L). Immunoreactive hK2 changed little in samples stored for up to 1 month at −70 °C.
Conclusions: The thK2 assay recognizes all forms of hK2 that have been found in bodily fluids to date.
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Affiliation(s)
- Judith A Finlay
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - John R Day
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Cindy L Evans
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Robert Carlson
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Kristine Kuus-Reichel
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Lisa S Millar
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Stephen D Mikolajczyk
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Marcia Goodmanson
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905
| | - George G Klee
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905
| | - Harry G Rittenhouse
- Research Department, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
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22
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Tello FL, Prats CH, González MD. Free and complexed prostate-specific antigen (PSA) in the early detection of prostate cancer. Clin Chem Lab Med 2001; 39:116-20. [PMID: 11341744 DOI: 10.1515/cclm.2001.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We evaluated the analytical performance and diagnostic utility of complexed prostate-specific antigen (CPSA) and their ratios, complexed-to-total PSA (C/T PSA) and free-to-complexed PSA (F/C PSA), in comparison with the total PSA (TPSA) and free-to-total PSA ratio (F/T PSA) as means of diagnosing prostate cancer (PC). Samples (n=101) were drawn from men with no evidence of malignancy (n=80) and from men with PC (n=21) at biopsy. For determination of the F/T PSA ratio, the DPC Immulite-2000 method was used; and the Bayer Immuno-1 CPSA and TPSA assays were used to determine the C/T PSA ratio. The Bayer Immuno-1 CPSA assay provides accurate and precise CPSA values in human serum. The performance of the different forms and ratios was compared using receiver operating characteristic curve analysis. CPSA had the greatest area under the curve (AUC, 0.689) although it was not statistically different from the other parameters. A cut-off value of 4.66 ng/ml for CPSA provided a specificity of 38% and a sensitivity of 93%. The F/C PSA ratio maintained a sensitivity of 93% and had an increased specificity of 41%. The measurement of CPSA provides a slight increase in specificity compared with the use of the TPSA in the early detection of prostate cancer.
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Affiliation(s)
- F L Tello
- Servicio de Análisis Clínicos, Hospital General Universitario de Elche, Partida Huertos y Molinos, Alicante, Spain
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23
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Peter J, Unverzagt C, Hoesel W. Analysis of Free Prostate-specific Antigen (PSA) after Chemical Release from the Complex with α1-Antichymotrypsin (PSA-ACT). Clin Chem 2000. [DOI: 10.1093/clinchem/46.4.474] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AbstractBackground: Prostate-specific antigen (PSA), a marker for prostate cancer (CaP), forms a covalent complex with α1-antichymotrypsin (ACT) in human blood. Structural analysis of the PSA-ACT complex is difficult, and complexation may be a reason for biased immunological assays when compared with the analysis of free PSA. We developed a method to cleave the PSA-ACT complex chemically. The liberated PSA was thus available for analysis as free PSA (F-PSA).Methods: PSA was released from the PSA-ACT complex by cleaving the interprotein ester bond with ethanolamine under alkaline conditions. The release was followed by reversed-phase HPLC and an immunoassay for F-PSA. Released PSA obtained from human blood was further immunopurified and analyzed by matrix-assisted laser desorption-induced time of flight (MALDI-TOF) mass spectrometry.Results: In vitro-prepared PSA-ACT complex was completely cleaved by treatment with nucleophilic compounds such as ethanolamine at pH 9–10. The released PSA was stable under these conditions and could be measured by reversed-phase HPLC as well as the ENZYMUN® immunoassay for F-PSA. When plasma from a CaP patient [containing 190 μg/L F-PSA and 1890 μg/L total PSA (T-PSA)] was treated under similar conditions, a concentration of ∼1600 μg/L F-PSA was measured at the end of the incubation, indicating that the PSA-ACT complex was completely cleaved. Two benign prostatic hyperplasia and CaP sera panels (12 and 13 sera, respectively) containing 4–45 μg/L T-PSA were similarly treated. The concentrations of F-PSA measured after incubation were, on average, 85% of the T-PSA values of the untreated sera. Finally, the PSA released from the complex of the CaP plasma was isolated by immunosorption, analyzed by MALDI-TOF mass spectrometry, and compared to PSA obtained from semen. The intact PSA as well as the peptides observed after digestion with endoproteinase Lys C did not reveal any structural difference between the PSA from these two sources.Conclusions: PSA complexed to ACT in plasma of a CaP patient seems to be structurally very similar to the PSA reference material from semen. The release of PSA from the PSA-ACT complex allows F-PSA and T-PSA to be measured by the same immunological assay, thus eliminating any possible bias between two different assays.
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Affiliation(s)
- Jochen Peter
- Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Carlo Unverzagt
- Institut für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching, Germany
| | - Wolfgang Hoesel
- Roche Diagnostics GmbH, Nonnenwaldstrasse 2, 82372 Penzberg, Germany
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24
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Fox MP, Reilly AA, Schneider E. Effect of the Ratio of Free to Total Prostate-specific Antigen on Interassay Variability in Proficiency Test Samples. Clin Chem 1999. [DOI: 10.1093/clinchem/45.8.1181] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background: Up to sevenfold differences were observed between total prostate-specific antigen (PSA) methods for New York State Proficiency Test samples prepared with seminal fluid PSA in human female serum. Because the PSA was mainly in its free form under these conditions, we wanted to determine whether a defined mixture of free and complexed PSA would reduce the interassay differences.
Methods: We prepared a series of five solutions of 60 g/L bovine serum albumin with 10 μg/L total PSA consisting of varied proportions of free, noncomplexible PSA, and α1-antichymotrypsin (ACT)-complexed PSA from 0% to 100%. Two hundred seventy laboratories measured the total PSA in these samples, and 16 laboratories also analyzed the samples for free PSA. The results were used to calculate free/total PSA ratios.
Results: Interassay CVs for total PSA measurements were ∼7% at 10–15% free PSA but became gradually larger as the free/total PSA ratio increased. Measured free-PSA concentrations were similar within each sample (mean CV, 12%), and the results were relatively independent of the proportion of free PSA in the samples. Twofold discrepancies between actual and expected ratios were observed with some methods at 100% free PSA and to a lesser degree at 30% free PSA. At 100% free PSA, the relatively higher total-PSA values measured by nonequimolar methods yielded low free/total PSA ratios of 50–60%. In contrast, the lower total PSA values obtained by equimolar methods yielded ratios close to the expected 100%.
Conclusions: Preparing proficiency test samples with a 10:90 mixture of free, noncomplexible PSA:PSA-ACT is a viable alternative to the use of seminal fluid PSA. Furthermore, the method used to measure total PSA may have a substantial impact on the calculated proportion of free PSA and hence may have clinical relevance.
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Affiliation(s)
- M Pat Fox
- Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
| | - Andrew A Reilly
- Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
- Biometry and Statistics, School of Public Health, University at Albany, Albany, NY 12201
| | - Erasmus Schneider
- Division of Molecular Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201
- Departments of Biomedical Sciences and
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Blijenberg BG, Storm BN, Kruger AE, Schröder FH. On the standardization of total prostate-specific antigen: an exercise with two reference preparations. Clin Chem Lab Med 1999; 37:545-52. [PMID: 10418746 DOI: 10.1515/cclm.1999.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study, 112 serum samples were analyzed for total prostate-specific antigen with three well-established assays i.e. Tandem R and Tandem E (both from Hybritech Inc., San Diego, USA) and Prostatus Free/Total from Wallac Oy, Turku, Finland. Thirty-two samples were collected from prostate cancer patients, 32 from patients with benign prostate hyperplasia and 48 from men participating in a screening study for prostate cancer. The aim of the study was to compare the results before and after recalculation with the data obtained with two reference preparations for total prostate-specific antigen: Stanford 90:10 PSA Calibrator and Certified Reference Material 613 Prostate-Specific Antigen. Comparing the actual results revealed almost perfect correlations between Tandem R and Tandem E and between both Tandem assays and Prostatus. We observed statistically significant differences in accuracy between Tandem R and Tandem E: y(Tandem E)= 1.05 x(Tandem R)+0.07 and between Tandem E and Prostatus: y(Prostatus)= 0.94 x(Tandem E)+0.02 In both comparisons prostate-specific antigen values ranged from 0-40 microg/l. Recalculation with both reference preparations did not solve these discrepancies. One exception was the combination Tandem R and Tandem E. The application of either reference preparation solved the differences in accuracy here. In conclusion, even after recalibration, assays for total prostate-specific antigen are still not completely interchangeable.
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Affiliation(s)
- B G Blijenberg
- Department of Clinical Chemistry, University Hospital Rotterdam, The Netherlands.
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26
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España F, Royo M, Martínez M, Enguídanos MJ, Vera CD, Estellés A, Aznar J, Jiménez-Cruz JF, Heeb MJ. Free and complexed prostate specific antigen in the differentiation of benign prostatic hyperplasia and prostate cancer: studies in serum and plasma samples. J Urol 1998; 160:2081-8. [PMID: 9817329 DOI: 10.1097/00005392-199812010-00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE We prospectively evaluated serum and plasma concentrations of total and free prostate specific antigen (PSA), and PSA complexed to alpha1-antichymotrypsin in 170 patients who underwent biopsy, including 59 with prostate cancer and 111 with benign prostatic hyperplasia. We compared the usefulness of the ratios of free-to-total and complexed-to-total PSA for distinguishing between prostate cancer and benign prostatic hyperplasia, and studied the influence of blood clotting on the ratios. MATERIALS AND METHODS Blood samples were processed to generate serum and citrated plasma. To calculate complexed-to-total and free-to-total PSA we assayed plasma and serum samples for total and complexed PSA using homemade immunoassays, and total and free PSA using the Immulite assay. The 2 total PSA assays were compared using the Tandem-E PSA assay. Receiver operating characteristics curves were constructed for the total population, and for 2 to 20, 4 to 20, 2 to 10 and 4 to 10 ng./ml. total PSA. RESULTS In all groups complexed-to-total PSA had higher specificity than free-to-total and total PSA, especially at 90 to 100% sensitivity. Generally citrated plasma samples provided higher specificity than serum samples for all sensitivity values. The best performance for complexed-to-total and free-to-total PSA was obtained in the subset of patients in whom total PSA was 2 to 10 ng./ml. CONCLUSIONS Our results indicate that the complexed-to-total PSA ratio performed better for classifying disease status than the free-to-total PSA ratio in the whole patient population and in the diagnostic gray zone of 2 to 10 ng./ml. In addition, plasma samples should be used to calculate the complexed-to-total and free-to-total PSA ratio.
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Affiliation(s)
- F España
- Department of Urology, La Fe University Hospital, Valencia, Spain
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27
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ESPANA FRANCISCO, ROYO MONTSERRAT, MARTINEZ MANUEL, ENGUIDANOS MARIAJ, VERA CESARD, ESTELLES AMPARO, AZNAR JUSTO, JIMENEZ-CRUZ JFERNANDO, HEEB MARYJ. FREE AND COMPLEXED PROSTATE SPECIFIC ANTIGEN IN THE DIFFERENTIATION OF BENIGN PROSTATIC HYPERPLASIA AND PROSTATE CANCER: STUDIES IN SERUM AND PLASMA SAMPLES. J Urol 1998. [DOI: 10.1016/s0022-5347(01)62248-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- FRANCISCO ESPANA
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - MONTSERRAT ROYO
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - MANUEL MARTINEZ
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - MARIA J. ENGUIDANOS
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - CESAR D. VERA
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - AMPARO ESTELLES
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - JUSTO AZNAR
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - J. FERNANDO JIMENEZ-CRUZ
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
| | - MARY J. HEEB
- From the Departments of Urology and Clinical Pathology and Research Center, La Fe University Hospital, Valencia, Spain, and Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, California
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Kochañska-Dziurowicz AA, Mielniczuk MR, Stojko A, Kaletka J. The clinical utility of measuring free-to-total prostate-specific antigen (PSA) ratio and PSA density in differentiating between benign prostatic hyperplasia and prostate cancer. BRITISH JOURNAL OF UROLOGY 1998; 81:834-8. [PMID: 9666767 DOI: 10.1046/j.1464-410x.1998.00643.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To evaluate the role of free-to-total prostate-specific antigen ratio (f/tPSA), prostate volume and PSA density in differentiating between men with prostate cancer and benign prostatic hyperplasia (BPH). PATIENTS AND METHODS The study comprised 51 patients who were assessed after transurethral electroresection of the prostate (16 with prostate cancer and 35 with BPH). Patients with a tPSA of < or = 4.0 ng/mL and > or = 30.0 ng/mL were excluded from the analysis. Total and fPSA were measured using an immunoradiometric assay and prostate volume was determined by transrectal ultrasonography. The incidence of prostate cancer and BPH was then compared with the PSA variables to determine specificity and predictive value. RESULTS Most patients with BPH had a tPSA of 4.0-6.0 ng/mL; no patients with BPH had a tPSA of > 20.0 ng/mL. Most patients with prostate cancer had a f/tPSA of 6-10%. The area under the receiver operating characteristic curve for f/tPSA was significantly greater than that for tPSA (P < 0.003). CONCLUSIONS The measurement of f/tPSA and PSA density increase the specificity of the differential diagnosis between BPH and prostate cancer.
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Affiliation(s)
- A A Kochañska-Dziurowicz
- Institute of Occupational Medicine and Environmental Health, Department of Radioisotope Clinical Diagnostic, Sosnowiec, Poland
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Wilson MJ. Prostate-specific antigen (hK3) and human prostatic glandular kallikrein (hK2) in the detection of early stage human prostate cancer. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1998; 131:298-9. [PMID: 9579381 DOI: 10.1016/s0022-2143(98)90178-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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