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van der Toom EE, Axelrod HD, de la Rosette JJ, de Reijke TM, Pienta KJ, Valkenburg KC. Prostate-specific markers to identify rare prostate cancer cells in liquid biopsies. Nat Rev Urol 2019; 16:7-22. [PMID: 30479377 DOI: 10.1038/s41585-018-0119-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Despite improvements in early detection and advances in treatment, patients with prostate cancer continue to die from their disease. Minimal residual disease after primary definitive treatment can lead to relapse and distant metastases, and increasing evidence suggests that circulating tumour cells (CTCs) and bone marrow-derived disseminated tumour cells (BM-DTCs) can offer clinically relevant biological insights into prostate cancer dissemination and metastasis. Using epithelial markers to accurately detect CTCs and BM-DTCs is associated with difficulties, and prostate-specific markers are needed for the detection of these cells using rare cell assays. Putative prostate-specific markers have been identified, and an optimized strategy for staining rare cancer cells from liquid biopsies using these markers is required. The ideal prostate-specific marker will be expressed on every CTC or BM-DTC throughout disease progression (giving high sensitivity) and will not be expressed on non-prostate-cancer cells in the sample (giving high specificity). Some markers might not be specific enough to the prostate to be used as individual markers of prostate cancer cells, whereas others could be truly prostate-specific and would make ideal markers for use in rare cell assays. The goal of future studies is to use sensitive and specific prostate markers to consistently and reliably identify rare cancer cells.
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Affiliation(s)
| | - Haley D Axelrod
- The James Buchanan Brady Urological Institute, Baltimore, MD, USA.,Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | | | - Kenneth J Pienta
- The James Buchanan Brady Urological Institute, Baltimore, MD, USA
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Simple and robust antibody microarray-based immunoassay platform for sensitive and selective detection of PSA and hK2 toward accurate diagnosis of prostate cancer. SENSING AND BIO-SENSING RESEARCH 2015. [DOI: 10.1016/j.sbsr.2015.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
This article updates advances in prostate cancer screening based on prostate-specific antigen, its derivatives, and human kallikrein markers. Many men are diagnosed with indolent disease not requiring treatment. Although there is evidence of a survival benefit from screening, the numbers needed to screen and treat remain high. There is risk of exposing men to the side effects of treatment for nonthreatening disease. A screening test is needed with sufficiently good performance characteristics to detect disease at an early stage so treatment may be offered with curative intent, while reducing the number of negative or unnecessary biopsies.
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Affiliation(s)
- Richard J Bryant
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Headley Way, Headington, Oxford OX3 9DU, UK
| | - Hans Lilja
- Nuffield Department of Surgical Sciences, John Radcliffe Hospital, University of Oxford, Headley Way, Headington, Oxford OX3 9DU, UK; Department of Laboratory Medicine, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue (Mailbox 213), New York, NY 10065, USA; Department of Surgery (Urology), Memorial Sloan-Kettering Cancer Center, 1275 York Avenue (Mailbox 213), New York, NY 10065, USA; Department of Medicine (GU-Oncology), Memorial Sloan-Kettering Cancer Center, 1275 York Avenue (Mailbox 213), New York, NY 10065, USA.
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Cary KC, Cooperberg MR. Biomarkers in prostate cancer surveillance and screening: past, present, and future. Ther Adv Urol 2013; 5:318-29. [PMID: 24294290 DOI: 10.1177/1756287213495915] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The use of biomarkers for prostate cancer (PCa) screening, detection, and prognostication have revolutionized the diagnosis and management of the disease. Current clinical practice has been driven largely by the utilization of prostate-specific antigen (PSA). The lack of specificity of PSA for PCa has led to both unnecessary biopsies and overdiagnosis of indolent cancers. The recent controversial recommendation by the United States Preventive Services Task Force against PCa screening has highlighted the need for novel clinically useful biomarkers. We review the literature on PCa biomarkers in serum, urine, and tissue. While these markers show promise, none seems poised to replace PSA, but rather may augment it. Further validation and consideration of how these novel markers improve clinical outcome is necessary. The discovery of new genetic markers shows promise in stratifying men with aggressive PCa.
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Affiliation(s)
- K Clint Cary
- University of California, San Francisco, CA, USA
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5
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Végvári A, Sjödin K, Rezeli M, Marko-Varga G. Quantification of human kallikrein-2 in clinical samples by selected reaction monitoring. J Proteome Res 2013; 12:4612-6. [PMID: 23978317 DOI: 10.1021/pr400423k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Recently, the number of mass spectrometry-based quantification assays has been increased, partially due to the global efforts of chromosome-centric human proteome project (C-HPP). Our goal at the Chromosome 19 Consortium is to provide novel selected reaction monitoring (SRM) assays of proteins coded on chromosome 19. We have selected the two most useful signature peptides (NSQVWLGR and HNLFEPEDTGQR) of human kallikrein-2 (hK2 - NX_P20151) and developed an SRM assay. Details of the analytical parameters, including multiple transitions by peptides, are presented. The endogenous levels of hK2 were determined in clinical samples (n = 35). The limit of quantification was also estimated by spiking heavy isotope-labeled peptides into seminal plasma samples at various concentrations (LOQ ≈ 29 ng/mL).
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Affiliation(s)
- Akos Végvári
- Clinical Protein Science & Imaging, Biomedical Center, Department of Measurement Technology and Industrial Electrical Engineering, Lund University , BMC C13, 221 84 Lund, Sweden
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Jansen FH, Roobol M, Jenster G, Schröder FH, Bangma CH. Screening for prostate cancer in 2008 II: the importance of molecular subforms of prostate-specific antigen and tissue kallikreins. Eur Urol 2008; 55:563-74. [PMID: 19058905 DOI: 10.1016/j.eururo.2008.11.040] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 11/21/2008] [Indexed: 11/17/2022]
Abstract
CONTEXT Over the past decades, prostate-specific antigen (PSA), its isoforms, and other members of the tissue kallikrein family have been of continuous interest with regard to early detection and screening for prostate cancer (PCa). OBJECTIVE This review strives to give an overview of the possible clinical utilities of these markers, focused on early diagnostics and PCa screening. EVIDENCE ACQUISITION Using the Medline database, a literature search was performed on the role of molecular subforms of PSA and other members of the tissue kallikrein family in PCa detection. EVIDENCE SYNTHESIS With respect to PSA isoforms, only the combination of the various truncated forms (pPSA) shows additional value over total PSA (tPSA) and free PSA (fPSA) in PCa detection within the range of 2-10 ng/ml tPSA. At a high sensitivity for PCa, the specificity of the ratio of pPSA to fPSA (%pPSA) is, in general, better than that of the ratio of fPSA to tPSA (%fPSA), with a gain of 5-11%. The (-2)pPSA, (-4)pPSA, (-5)pPSA, (-7)pPSA, and benign PSA (BPSA) isoforms generally show no additional value over either pPSA or the existing parameters of tPSA and fPSA. Of the other members of the tissue kallikrein family, most studies on human kallikrein 2 (hK2) show an additional value of the ratio of hK2 to fPSA (%hK2) over %fPSA alone in PCa prediction. Other tissue kallikreins cannot be recommended for diagnosing PCa, due to the lack of additional value over tPSA or fPSA or to insufficient research. Regarding a prognostic role, the value of PSA subforms as well as of other members of the tissue kallikrein family is limited with regard to existing parameters. CONCLUSIONS pPSA and hK2 are able to improve PCa diagnosis in the range of 4-10 ng/ml tPSA over the existing variables tPSA and fPSA.
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Affiliation(s)
- Flip H Jansen
- Department of Urology, Erasmus MC, Rotterdam, The Netherlands.
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Alapont Alacreu JM, Navarro Rosales S, Budía Alba A, España Furió F, Morera Martínez F, Jiménez Cruz JF. [PSA and hK2 in the diagnosis of prostate cancer]. Actas Urol Esp 2008; 32:575-88. [PMID: 18655340 DOI: 10.1016/s0210-4806(08)73891-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Serum markers for prostate carcinoma are widely applied for the purpose of early detection of cancer and the differentiation between benign and malignant disease, for the pre-treatment staging of detected prostatic cancers, and for the monitoring of prostate cancer after curative or palliative therapies. Since its discovery in 1979, serum PSA has been the most powerful marker of prostate cancer, but, when used alone, PSA is not sufficiently sensitive or specific to consider it an ideal tool for the early detection or staging of prostate cancer. To optimize the use of PSA, the concepts of PSA velocity, PSA density, and age-related PSA values were developed. Moreover, the molecular forms of PSA, especially the percentage of free PSA, seem to be useful tools for the detection of prostate cancer in men with slightly elevated total PSA. Human kallikrein 2 (hK2), a serine protease closely related to PSA that also is expressed predominantly in the prostate, is a new complementary marker to PSA for early detection of prostate cancer. In this review, we examine PSA testing and its effectiveness in the diagnosis of prostate cancer. Further, we also evaluate recent literature regarding the use of hk2.
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Väisänen V, Peltola MT, Lilja H, Nurmi M, Pettersson K. Intact free prostate-specific antigen and free and total human glandular kallikrein 2. Elimination of assay interference by enzymatic digestion of antibodies to F(ab')2 fragments. Anal Chem 2007; 78:7809-15. [PMID: 17105175 DOI: 10.1021/ac061201+] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Various blood constituents can interfere with immunoassays, usually by binding the Fc portion of antibodies. Our previously developed assays for intact free prostate-specific antigen (PSA), free human kallikrein 2 (hK2), and total hK2 frequently yielded falsely high results despite including an excess of scavenger antibodies. We investigated whether this interference could be eliminated by replacing monoclonal capture or tracer antibodies with F(ab')2 or recombinant Fab fragments. Female heparin plasma samples (n = 1092), which should have negligible PSA and hK2, and male samples (n = 957) were analyzed to identify samples manifesting interference, which then were used to optimize protocols for the immunoassays. We compared original assays (monoclonal antibodies) versus optimized assays (F(ab')2 fragments: denatured mouse IgG added as scavenger) using another set of EDTA plasma (n = 113), heparin plasma (n = 160), and serum samples (n = 171). With the original assays, the frequency of falsely elevated hK2 and intact free PSA was 15 and 13%, respectively. The optimized assays eliminated 70-85% of these falsely elevated results and importantly reduced the magnitude in the remainder. F(ab')2 fragmentation was the most important factor in reducing interference. The optimized intact free PSA, free hK2, and total hK2 assays manifested high accuracy close to the lower limit of detection.
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Affiliation(s)
- Ville Väisänen
- Department of Biotechnology, University of Turku, Turku, Finland.
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9
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Väisänen V, Pettersson K, Alanen K, Viitanen T, Nurmi M. Free and total human glandular kallikrein 2 in patients with prostate cancer. Urology 2006; 68:219-25. [PMID: 16844459 DOI: 10.1016/j.urology.2006.01.075] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2005] [Revised: 12/27/2005] [Accepted: 01/30/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES The use of prostate-specific antigen (PSA, hK3) results in the overdiagnosis and overtreatment of prostate cancer. Markers are needed that could identify aggressive, fast-growing tumors and help decide which patients would benefit most from aggressive treatment. Human glandular kallikrein 2 (hK2) could be such a marker. The aim of this study was to test how PSA and hK2 could predict the pathologic stage and grade in a set of patients with clinically organ-confined disease. METHODS Heparin plasma was collected from 188 patients who had undergone radical prostatectomy at the Turku University Central Hospital. Total and free PSA, as well as total and free hK2, were measured and the results compared with the pathologic TNM stage, tumor World Health Organization grade, and Gleason score. RESULTS Free and total hK2 performed similarly to PSA in their ability to separate groups of patients with different stages or grades. Concentrations of both kallikreins were significantly different in patients with World Health Organization grade 1 cancer compared with grade 2. Neither marker could separate patients with different Gleason scores. Although PSA concentrations increased most between patients with Stage pT2b and those with pT3a, the increase in hK2 was most pronounced between those with Stage pT3a and those with pT3b. CONCLUSIONS Although hK2 could not predict the cancer stage or grade better than PSA, changes in the hK2 and PSA concentrations occurred at different points in cancer progression. hK2 may have a role in the prognosis of prostate cancer, but additional studies with longer follow-up are required to determine whether hK2 can help when selecting treatment options.
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Affiliation(s)
- Ville Väisänen
- Department of Biotechnology, University of Turku, Turku, Finland.
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Lubaroff DM, Konety B, Link BK, Ratliff TL, Madsen T, Shannon M, Ecklund D, Williams RD. Clinical protocol: phase I study of an adenovirus/prostate-specific antigen vaccine in men with metastatic prostate cancer. Hum Gene Ther 2006; 17:220-9. [PMID: 16454655 DOI: 10.1089/hum.2006.17.220] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- David M Lubaroff
- Department of Urology and Roland and Ruby Holden Cancer Research Laboratories, Holden Comprehensive Cancer Center, University of Iowa, Iowa City, IA 52242, USA.
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Lubaroff DM, Konety B, Link BK, Link TL, Madsen T, Shannon M, Ecklund D, Williams RD. Clinical Protocol: Phase I Study of an Adenovirus/Prostate-Specific Antigen Vaccine in Men with Metastatic Prostate Cancer. Hum Gene Ther 2006. [DOI: 10.1089/hum.2006.17.ft-168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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12
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Chiang CH, Hong CJ, Chang YH, Chang LS, Chen KK. HUMAN KALLIKREIN-2 GENE POLYMORPHISM IS ASSOCIATED WITH THE OCCURRENCE OF PROSTATE CANCER. J Urol 2005; 173:429-32. [PMID: 15643194 DOI: 10.1097/01.ju.0000148964.92943.39] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Human glandular kallikrein, which is encoded by the human kallikrein-2 (KLK2) gene, is significantly associated with the occurrence of prostate cancer (PCa). We tested the association between a functional C748T polymorphism of the KLK2 gene and the occurrence of PCa. MATERIALS AND METHODS Peripheral venous blood samples were obtained from 254 patients with PCa and 168 controls with benign prostatic hyperplasia. All control subjects had normal serum prostate specific antigen and proved to be free from malignancy on pathological examination of resected prostatic tissues. Serum prostate specific antigen, testosterone, Gleason score, clinical and pathological stage, tumor and prostate volume of the patients were investigated. The KLK2 gene polymorphism was determined by the polymerase chain reaction based restriction fragment length polymorphism method. RESULTS The PCa group had a younger mean age +/- SEM (73.0 +/- 0.5 vs 74.7 +/- 0.5 years, p = 0.010) and higher C allele frequency (82.1% vs 74.7%, p = 0.010) than the control group. The frequency of the CC, CT and TT genotypes was 65.7%, 32.7% and 1.6% in patients with PCa, and 56.0%, 37.5% and 6.5%, respectively, in controls (p = 0.010). C allele carriers (CC and CT genotypes) were at significantly higher risk for PCa than TT homozygous subjects (p = 0.002). CC homozygous subjects were at significantly higher risk for PCa than T allele carriers (CT and TT genotypes) (p = 0.043). The PCa subgroup of patients with pathologically proved, localized PCa also had a higher frequency of the C allele (87.5% vs 74.7%, p = 0.026) and CC genotypes (78.7% vs 56.0%, p = 0.019) than controls. CONCLUSIONS Our results suggest that the C allele of the functional C748T polymorphism of KLK2 may increase the risk of PCa.
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Affiliation(s)
- Chih-Hung Chiang
- Department of Surgery (Division of Urology), Taipei Veterans General Hospital, Taipei, Taiwan, Republic of China
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13
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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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14
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Becker C, Piironen T, Pettersson K, Hugosson J, Lilja H. Testing in Serum for Human Glandular Kallikrein 2, and Free and Total Prostate Specific Antigen in Biannual Screening for Prostate Cancer. J Urol 2003; 170:1169-74. [PMID: 14501718 DOI: 10.1097/01.ju.0000086640.19892.0b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE We investigated the value of serum measurements for glandular kallikrein 2 (hK2), and free (f) and total (t) prostate specific antigen (PSA) in a second round of biannual screening for prostate cancer. MATERIALS AND METHODS In 1995 to 1996, 5,853 of 9,811 randomly selected men in Göteborg, Sweden 50 to 66 years old had PSA measurements. Of 660 men 611 with tPSA 3 ng/ml or greater underwent biopsy and 145 had cancer. All were re-invited 2 years later for PSA testing, and 506 of 596 men with tPSA 3 ng/ml or greater underwent biopsy and 113 cancers were detected. We analyzed hK2, tPSA and fPSA in 423 of 453 (93%) men who underwent biopsy in 1997 to 1998 who were also screened in 1995 to 1996. RESULTS The 99 of 423 (23%) men who underwent biopsy diagnosed with prostate cancer in 1997 to 1998 had significantly different tPSA, percent fPSA and hK2 x tPSA/fPSA compared to the men with negative biopsies from 2 years earlier. The largest area under curve was obtained for hK2 x tPSA/fPSA in serum from 1995 to 1996 and from 1997 to 1998, but the difference was not significant compared to tPSA and percent fPSA. In serum from 1997 to 1998 measurements of hK2 x tPSA/fPSA gave significantly higher specificity than tPSA at 85% sensitivity, and significantly higher specificity than tPSA and percent fPSA at 70% to 75% sensitivity. In addition, levels of hK2 and hK2 x tPSA/fPSA manifested a significantly greater 2-year increase in men with cancer compared to those with benign biopsies. CONCLUSIONS In men with tPSA levels 3.0 ng/ml or greater who were not diagnosed with cancer during a first round of screening, hK2 measurements enhanced specificity compared to tPSA testing at moderately high sensitivity, and manifested a greater 2-year increase in men with cancer.
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Affiliation(s)
- Charlotte Becker
- Department of Clinical Chemistry, Lund University, University Hospital Malmö, Sweden.
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Barki-Harrington L, Bookout AL, Wang G, Lamb ME, Leeb-Lundberg LMF, Daaka Y. Requirement for direct cross-talk between B1 and B2 kinin receptors for the proliferation of androgen-insensitive prostate cancer PC3 cells. Biochem J 2003; 371:581-7. [PMID: 12534343 PMCID: PMC1223306 DOI: 10.1042/bj20021708] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2002] [Revised: 01/03/2003] [Accepted: 01/20/2003] [Indexed: 12/15/2022]
Abstract
Stimulation of endogenous kinin receptors promotes growth of androgen-independent prostate cancer PC3 cells via activation of the mitogenic extracellular-signal-regulated kinase (ERK) pathway. In the present study, we show that kinin-mediated mitogenic signalling and prostate-cell growth involves two subtypes of bradykinin (BK) receptors, B1R and B2R. Specific stimulation of either B1R or B2R by their respective agonists des-Arg(9)-BK and Lys-BK promoted ERK activation and cell growth, whereas selective blockade with specific antagonists des-Arg(9)-[Leu(8)]BK and Hoe 140 respectively obliterated this effect, indicating the presence of both receptor subtypes. However, blockade of B1R also inhibited B2R-mediated ERK activation and cell growth, and, similarly, antagonism of B2R inhibited the B1R-mediated response. Furthermore, both B1R and B2R agonists promoted internalization of B1R, whereas both receptor antagonists blocked this effect. The B1R ligands des-Arg(9)-BK and des-Arg(9)-[Leu(8)]BK had no effect on the binding of BK to B2R, as demonstrated by radioligand competitive binding studies. However, blockade of either B1R or B2R impaired the ability of the reciprocal receptor to produce inositol phosphates, suggesting that the interaction between B1R and B2R is proximal to activation of phospholipase C. These results provide evidence for the existence of B1R-B2R complexes in prostate cancer PC3 cells and demonstrate that antagonism of one receptor interferes with the signalling ability of the other, possibly at the level of receptor-Galpha(q) protein coupling. Selective inhibition of B1R, which is up-regulated in injured and cancerous tissue, may be beneficial for the treatment of advanced prostate cancer.
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Haese A, Vaisanen V, Finlay JA, Pettersson K, Rittenhouse HG, Partin AW, Bruzek DJ, Sokoll LJ, Lilja H, Chan DW. Standardization of two immunoassays for human glandular kallikrein 2. Clin Chem 2003; 49:601-10. [PMID: 12651813 DOI: 10.1373/49.4.601] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Measurement of human kallikrein 2 (hK2) has improved early detection and staging of prostate cancer. However, reported concentrations of hK2 among currently used assays have not been standardized in any way. We compared two hK2 assays and five different recombinant hK2 variants (rhK2) and suggest a common calibrator as an important step and putative reference substance in hK2 assay standardization. METHODS We measured 146 sera by two hK2 assays, using assay-specific calibrators to assess the difference between the two assays. Serial dilutions of five rhK2 preparations were measured repeatedly, with one preparation assigned as calibrator and the others as unknowns to define which variant provided the closest match between the two assays. This rhK2 variant was used to recalibrate both assays. We measured hK2 concentrations in the same 146 patients to evaluate the change in the difference. RESULTS Use of assay-specific calibrators for comparison of the two assays yielded a Deming regression equation of: y = 0.789 (95% confidence interval, 0.674-0.922)x + 0.014 (0.004-0.025) micro g/L; R(2) = 0.667. Analysis of five rhK2 variants revealed that the enterokinase (ek)-rhK2 form provided the best match between both assays. Using the ek-rhK2 as a common calibrator, we observed a change in the slope of the regression curve to: y = 1.106 (0.872-1.340)x + 0.006 (-0.002 to 0.016) micro g/L; R(2) = 0.648, suggesting an increase in the mean estimate of agreement between the two assays. CONCLUSION Calibration with a common calibrator substantially increased agreement between the assays. The ek-rhK2 variant provided the best performance of all tested rhK2 variants and should undergo mass spectrometry and amino acid analysis for exact mass determination and value assignment to evaluate its potential as a reference material for immunoassays for hK2.
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Affiliation(s)
- Alexander Haese
- Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University Medical Institutions, Baltimore, MD 21287, USA.
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17
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Haese A, Graefen M, Becker C, Noldus J, Katz J, Cagiannos I, Kattan M, Scardino PT, Huland E, Huland H, Lilja H. The role of human glandular kallikrein 2 for prediction of pathologically organ confined prostate cancer. Prostate 2003; 54:181-6. [PMID: 12518322 DOI: 10.1002/pros.10180] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
BACKGROUND In recent studies serum levels of human glandular kallikrein 2 (hK2) demonstrated significant differences in pathologically organ-confined versus non-organ-confined prostate cancer (PCa). In this study we investigated whether hK2 adds independent information when considered together with traditionally used parameters to predict organ confined (pT2a/b) PCa. METHODS Serum levels of hK2, total and free prostate-specific antigens (PSA) were obtained one day before radical prostatectomy in 245 consecutive men. These were included with clinical stage and biopsy Gleason grade into univariate analysis and multivariate logistic regression models. RESULTS pT2a/b PCa was found in n = 148 patients. In univariate analysis all preoperative parameters demonstrated significant association with the presence of pT2a/b PCa. Using multivariate logistic regression model hK2 (P = 0.022), clinical stage (P < 0.0001), and Gleason grade (P < 0.0001) were independent predictors of pT2a/b PCa whereas PSA (P = 0.3) was not. In bootstrap corrected logistic regression based nomograms the addition of hK2 density marginally enhanced predictive accuracy when PSA, PSA density, clinical stage, and Gleason grade were considered (AUC = 0.879 without hK2 density and 0.883 with hK2 density). CONCLUSIONS hK2 and hK2 density could independently predict pT2a/b PCa. However, improvement in predictive accuracy was marginal when nomograms based on traditional variables were complemented with this serum marker.
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Affiliation(s)
- Alexander Haese
- Department of Urology, University Hospital Hamburg, Germany.
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Leinonen J, Wu P, Stenman UH. Epitope Mapping of Antibodies against Prostate-specific Antigen with Use of Peptide Libraries. Clin Chem 2002. [DOI: 10.1093/clinchem/48.12.2208] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
AbstractBackground: Prostate-specific antigen (PSA) is the most important marker for prostate cancer, but PSA concentrations determined by various assays can differ significantly because of differences in specificity of the antibodies used. To identify epitopes recognized by various monoclonal antibodies (MAbs) to PSA, we have isolated peptides that react with the paratopes of these.Methods: Six anti-PSA MAbs representing three major epitope groups were screened with five cyclic phage display peptide libraries. After selection, the peptide sequences were determined by sequencing of the relevant part of viral DNA. Binding of the phage peptides to the MAbs was monitored by immunoassay.Results: For each MAb, several paratope-binding peptides with distinct sequence motifs were identified, but only ∼10% showed similarity with the PSA sequence. Some of these correctly predicted the location of the epitopes. By sequential panning of the library with two closely related MAbs, we identified peptides reacting equally with both MAbs. When analyzed against a large panel of PSA MAbs, the peptides generally showed restricted specificity toward the MAb used for selection, but some peptides bound to several related MAbs.Conclusions: Most of the cyclic peptides selected with PSA MAbs are specific for the MAb used for selection and do not resemble any sequence on the antigen. Peptides reactive with two MAbs recognizing the same epitope can be obtained by sequential panning. This method can be used to predict the location of some epitopes, but additional methods are needed to confirm the result.
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Affiliation(s)
- Jari Leinonen
- Department of Clinical Chemistry, Helsinki University Central Hospital, FIN-0029 Helsinki, Finland
| | - Ping Wu
- Department of Clinical Chemistry, Helsinki University Central Hospital, FIN-0029 Helsinki, Finland
| | - Ulf-Håkan Stenman
- Department of Clinical Chemistry, Helsinki University Central Hospital, FIN-0029 Helsinki, Finland
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Jain S, Bhojwani AG, Mellon JK. Improving the utility of prostate specific antigen (PSA) in the diagnosis of prostate cancer: the use of PSA derivatives and novel markers. Postgrad Med J 2002; 78:646-50. [PMID: 12496317 PMCID: PMC1742550 DOI: 10.1136/pmj.78.925.646] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Prostate specific antigen (PSA) testing is now a routine part of the investigation of men with suspected prostate cancer. While a very useful test it still has its problems, in particular its lack of specificity means abnormal results are often caused by benign disease. This review describes the current problems with PSA testing in prostate cancer diagnosis and highlights potential ways in which these may be reduced.
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Affiliation(s)
- S Jain
- Division of Urology, University of Leicester, Leicester General Hospital, UK.
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20
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Becker C, Noldus J, Diamandis E, Lilja H. The role of molecular forms of prostate-specific antigen (PSA or hK3) and of human glandular kallikrein 2 (hK2) in the diagnosis and monitoring of prostate cancer and in extra-prostatic disease. Crit Rev Clin Lab Sci 2001; 38:357-99. [PMID: 11720279 DOI: 10.1080/20014091084236] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Prostate-specific antigen (PSA or hK3) is a glandular kallikrein with abundant expression in the prostate that is widely used to detect and monitor prostate cancer (PCa), although the serum level is frequently elevated also in benign and inflammatory prostatic diseases. PSA testing is useful for early detection of localized PCa and for the detection of disease recurrence after treatment. However, PSA has failed to accurately estimate cancer volume and preoperative staging. There is no PSA level in serum that definitively distinguishes men with benign conditions from those with prostate cancer, although PCa is rare in men with PSA levels in serum < 2.0 ng/ml. This prompted searches for enhancing parameters to combine with PSA testing, such as PSA density, PSA velocity, and age-specific reference ranges. Due to the protease structure, PSA occurs in different molecular forms in serum and their concentrations vary according to the type of prostatic disease. Human glandular kallikrein 2 (hK2) is very similar to PSA, but expressed at higher levels in prostate adenocarcinoma than in normal prostate epithelium. Blood testing for hK2 combined with different PSA forms improves discrimination of men with benign prostatic disease from those with prostate cancer. Many data have also been reported on the extra-prostatic expression of both PSA and hK2, and it is now believed that they may both have functions in tissues outside the prostate.
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Affiliation(s)
- C Becker
- Dept. of Clinical Chemistry, Lund University, Malmö University Hospital, Malmö, Sweden.
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21
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Haese A, Graefen M, Steuber T, Becker C, Pettersson K, Piironen T, Noldus J, Huland H, Lilja H. Human glandular kallikrein 2 levels in serum for discrimination of pathologically organ-confined from locally-advanced prostate cancer in total PSA-levels below 10 ng/ml. Prostate 2001; 49:101-9. [PMID: 11582588 DOI: 10.1002/pros.1123] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND We measured serum levels of human glandular kallikrein 2 (hK2) in patients treated with radical retropubic prostatectomy (rrP) for clinically localized prostate cancer (PCa) with a total PSA (tPSA)-level below 10 ng/ml to investigate whether hK2 can be applied to preoperatively distinguish organ-confined (pT2a/b) from nonorgan-confined (> or = pT3a)-PCa more accurately than total PSA. Further, we evaluated hK2, free- and tPSA-concentrations in all pathologic stages of PCa. METHODS 161 serum samples from men scheduled for rrP were collected 1 day before surgery prior to any prostatic manipulation. Pathologic work-up revealed > or = pT3a-PCa in 48 and pT2a/b-PCa in 113 patients. HK2-levels in serum were measured using an immunofluorometric assay with an analytical sensitivity of 0.5 pg/ml, a functional sensitivity of 5 pg/ml and insignificant cross-reactivity with PSA (< 0.005%). Total (tPSA) and free PSA (fPSA) levels were measured using a commercially available assay from which we calculated %fPSA and an algorithm that combined hK2 and PSA-levels [hK2] x [tPSA/fPSA]. Means, medians, and ranges were calculated for pT2a/b vs. >/= pT3a-PCa and for all pathologic stages. Statistical significance of differences was calculated using Mann-Whitney-U and Kruskal-Wallis tests. Calculation of receiver-operator-characteristic (ROC) curves were performed for hK2, [hK2] x [tPSA/fPSA] and tPSA to compare diagnostic performance. RESULTS A mean tPSA level in serum of 6.12 ng/ml in > or = pT3a-PCa was not significantly different (P = 0.366) from 5.78 ng/ml in pT2a/b-PCa. Also, there were no statistically significantly different levels of fPSA (P = 0.947) or %fPSA (0.292) for these two groups. By contrast, mean hK2-level in pT2a/b-PCa of 80 pg/ml was significantly different (P = 0.004) from a mean hK2 level of 120 pg/ml in > or = pT3a-PCa as shown by Mann-Whitney-analysis Moreover, the algorithm of [hK2] x [tPSA/fPSA] was significantly lower (P = 0.0004) in pT2a/b-PCa vs. > or = pT3a-PCa. Calculation of areas under curve (AUC) by receiver-operator-characteristics (ROC) demonstrated that the AUC for hK2 (0.64) was larger and the AUC for [hK2] x [tPSA/fPSA] (=0.68) significantly larger (P = 0.007) compared to the AUC of tPSA (0.55). Furthermore, Kruskal-Wallis Test revealed a highly significant correlation to pathologic stage using hK2 (P = 0.008) and [hK2] x [tPSA/fPSA] (P = 0.0015) compared to no significant differences in serum concentration of tPSA (P = 0.296). Also at tPSA-levels from 10-20 ng/ml, the hK2-levels in pT2a/b-PCa were close to significantly different (P = 0.051) from those in men with >/= pT3a-PCa, while the algorithm of [hK2] x [tPSA/fPSA] in that tPSA-range was significantly lower (P = 0.002) in pT2a/b-PCa compared to > or = pT3a0-PCa. CONCLUSIONS Highly significant differences in serum concentration enable hK2 to be a powerful predictor of organ-confined disease and pathologic stage of clinically localized prostate cancer, especially in the PSA-range below 10 ng/ml. As such, there are important clinical consequences for the application of hK2 for the adequate treatment of prostate cancer patients, i.e., the option of nerve-sparing surgery. (c) 2001 Wiley-Liss, Inc.
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Affiliation(s)
- A Haese
- Department of Urology, University Clinic Eppendorf, Hamburg, Germany.
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22
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Van Der Cruijsen-Koeter IW, Wildhagen MF, De Koning HJ, Schröder FH. The value of current diagnostic tests in prostate cancer screening. BJU Int 2001; 88:458-66. [PMID: 11589658 DOI: 10.1046/j.1464-4096.2001.02381.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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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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Siivola P, Pettersson K, Piironen T, Lövgren T, Lilja H, Bjartell A. Time-resolved fluorescence imaging for specific and quantitative immunodetection of human kallikrein 2 and prostate-specific antigen in prostatic tissue sections. Urology 2000; 56:682-8. [PMID: 11018639 DOI: 10.1016/s0090-4295(00)00671-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
OBJECTIVES To design protocols for specific and quantitative immunohistochemical detection of human kallikrein 2 (hK2) using lanthanide chelate-labeled monoclonal antibodies (Mabs) and time-resolved fluorescence imaging. METHODS Anti-prostate-specific antigen (PSA) Mabs were tested in microtiterplate assays for their ability to prevent PSA from cross-reacting with the anti-hK2 Mab 6H10. Europium-labeled 6H10 and terbium-labeled anti-PSA Mab 2E9, selected as the best blocker antibody, were used for dual-label immunodetection in routinely fixed benign (n = 7) and malignant (n = 5) prostate specimens. The amounts of IgG bound in tissue were calculated from drops containing known Mab concentrations. RESULTS The use of anti-PSA Mab 2E9 for blocking diminished the cross-reaction from 5% to 0.3%. In the analyzed tissues, there was considerable variation in staining intensity for both proteins; PSA signals varied from 0.1 to 36.6 times that of hK2, with on average 10-fold more bound anti-PSA Mab than anti-hK2 Mab. In malignant tissue, the amounts of bound IgGs were lower and more variable than in benign tissue using both the anti-PSA Mab and the anti-hK2 Mab. The variation in signal intensities for PSA and hK2 correlated significantly in benign tissue (P >0.05), but not in benign hyperplastic and malignant specimens (P <0.05). CONCLUSIONS Quantification of two lanthanide chelate-labeled antibodies bound in the same tissue section enabled comparison of PSA and hK2 content in individual cells. The average cellular content of hK2 relative to that of PSA was consistent with previous mRNA studies. The time-resolved fluorescence imaging-based quantification method has universal applicability in fixed tissue specimens.
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Affiliation(s)
- P Siivola
- Department of Biotechnology, University of Turku, Turku, Finland
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25
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Kumar A, Mikolajczyk SD, Hill TM, Millar LS, Saedi MS. Different proportions of various prostate-specific antigen (PSA) and human kallikrein 2 (hK2) forms are present in noninduced and androgen-induced LNCaP cells. Prostate 2000; 44:248-54. [PMID: 10906742 DOI: 10.1002/1097-0045(20000801)44:3<248::aid-pros10>3.0.co;2-d] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Human prostate-specific antigen (PSA) and human kallikrein 2 (hK2) are expressed primarily by prostate epithelial cells. PSA and hK2 both exist as free protein and complexed with protease inhibitors (e.g., alpha1-antichymotrypsin, ACT) in serum. The expression of PSA and hK2 in LNCaP cells is upregulated by androgen. METHODS LNCaP, a prostate cancer cell line that secretes both PSA and hK2, was used as a model to study the biosynthesis and processing of PSA and hK2 upon androgen induction. RESULTS Precursor (zymogen or pro) forms of both PSA and hK2 were detected in spent media of induced and noninduced LNCaP cells, indicating that PSA and hK2 are secreted as proPSA (pPSA) and prohK2 (phK2), respectively, and are converted to the mature forms extracellularly. A 3-fold higher ratio of mature to pPSA was detected in the spent media of mibolerone-induced LNCaP cells compared to noninduced cells. In addition to the inactive proform of PSA, more than half of the mature unclipped PSA present in the spent media did not complex with exogenously added ACT. Spent media of mibolerone-induced LNCaP cells contained nearly 100% mature hK2, whereas the spent media of noninduced cells contained mostly phK2. CONCLUSIONS These results indicate that androgens not only upregulate the expression of these kallikreins, but also have a significant effect on the processing of PSA and hK2. These results also show that LNCaP cells express a heterogeneous mixture of inactive PSA and hK2 forms that may serve as a model for the genesis of these forms in physiological fluids. These findings may also provide insights into the forms and ratios of PSA and hK2 in normal and malignant breast tissues.
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Affiliation(s)
- A Kumar
- Hybritech Incorporated, a subsidiary of Beckman Coulter, Inc., San Diego, California 92196-9006, USA
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26
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Becker C, Piironen T, Pettersson K, Hugosson J, Lilja H. Clinical value of human glandular kallikrein 2 and free and total prostate-specific antigen in serum from a population of men with prostate-specific antigen levels 3.0 ng/mL or greater. Urology 2000; 55:694-9. [PMID: 10792083 DOI: 10.1016/s0090-4295(99)00585-3] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To investigate the clinical value of human glandular kallikrein 2 (hK2) compared with free (f) and total (t) prostate-specific antigen (PSA) in the early detection of prostate cancer (PCa). METHODS In PCa screening conducted in 1995 to 1996 in Göteborg, Sweden, 5853 of 9811 randomly selected men (aged 50 to 66 years; median 61) accepted PSA testing; those with tPSA levels of 3. 0 ng/mL or greater were offered digital rectal examination, transrectal ultrasound, and sextant biopsies. Serum from 604 of 611 biopsied men (18% with positive digital rectal examinations, tPSA range 3.0 to 220 ng/mL, 144 men with PCa) was analyzed for hK2 (research assay) and tPSA and fPSA (Prostatus). Sera were stored at -20 degrees C for a maximum of 2 weeks for tPSA and fPSA and 3 years for hK2. RESULTS hK2 levels and hK2 x tPSA/fPSA values were significantly elevated in men with PCa. Receiver operating characteristic data revealed that the area under the curve for hK2 x tPSA/fPSA was significantly greater than that for tPSA and greater, but not significantly greater, than that for percent fPSA. Also, the cancer-detecting sensitivity was significantly improved (P <0.05) using hK2 x tPSA/fPSA compared with tPSA and percent fPSA at specificity levels of 75% to 90%. At 75% specificity, a sensitivity of 74% was obtained compared with 64% or 54% using percent fPSA or tPSA; at 90% specificity, the corresponding sensitivity level was 55%, 41%, and 36%, respectively. CONCLUSIONS Discrimination of men with and without PCa in a randomly selected population was improved by measuring hK2 in addition to tPSA and fPSA.
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Affiliation(s)
- C Becker
- Department of Clinical Chemistry, Lund University, University Hospital Malmö, Malmö, Sweden
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27
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Haese A, Becker C, Noldus J, Graefen M, Huland E, Huland H, Lilja H. Human glandular kallikrein 2: a potential serum marker for predicting the organ confined versus non-organ confined growth of prostate cancer. J Urol 2000; 163:1491-7. [PMID: 10751864 DOI: 10.1016/s0022-5347(05)67649-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE We measured serum levels of human glandular kallikrein 2 (hK2) in patients with prostate cancer treated with radical retropubic prostatectomy for clinically localized prostate cancer to determine whether preoperative hK2 levels discriminate stage pT2a/b from pathological stage T3a or greater cancer. This finding would help to predict preoperatively the organ confined versus non-organ confined growth of prostate cancer. MATERIALS AND METHODS A total of 68 consecutive men underwent radical retropubic prostatectomy for clinically localized prostate cancer. Serum was obtained 1 day preoperatively before prostatic manipulation. hK2, and total and free prostate specific antigen (PSA) were measured using immunofluorometric assays. Mean, median and range of hK2, total and free PSA, and the ratio of free-to-total PSA (percent free PSA) were calculated. Each analyte or combination of analytes was evaluated to determine whether it significantly contributed to enhance the discrimination of organ confined from non-organ confined cancer. We calculated the statistical significance of observed differences using the Mann-Whitney U and Kruskal-Wallis tests. Sensitivity and specificity calculations were performed for hK2, total PSA and the algorithm, (hK2) x (total PSA/free PSA) in addition to receiver operating characteristics curves and the respective areas under the curves. Multivariate logistic regression analysis was done for hK2, and total and free PSA RESULTS: Disease was organ and non-organ (extraprostatic extension) confined in 38 and 30 men, respectively. In organ confined cancer mean hK2 was significantly lower than in non-organ confined cancer (0.09 ng./ml., range less than 0.03 to 0.23 versus 0.30, range 0.04 to 0.94, p <0.0001). In addition, there was significantly higher free and total but not percent free PSA in non-organ than in organ confined cases. There were also statistically significant differences in hK2, free PSA and total PSA at each pathological disease stage (p <0.001, <0.01 and <0.05, respectively). Sensitivity for detecting organ confined disease was 37% at 100% specificity (correct identification of all non-organ confined cancer) using hK2 measurements compared with a sensitivity of 14% for total PSA. At a specificity of 95%, sensitivity was 40% for hK2 versus 23% for total PSA, which was a statistically significant gain in sensitivity (p <0.05). Receiver operating characteristics curves demonstrated that hK2 had the largest area under the curve, followed by the algorithm, (hK2) x (total PSA/free PSA), and total PSA (0.76, 0.75 and 0.72, respectively). However, none of area under the curve differences was statistically significant. CONCLUSIONS Compared with total and free PSA hK2 testing improved the preoperative evaluation of patients who underwent radical retropubic prostatectomy due to the superior discrimination of organ from non-organ confined cancer.
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Affiliation(s)
- A Haese
- Department of Urology, University Clinic Eppendorf, Hamburg, Germany
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28
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Nam RK, Diamandis EP, Toi A, Trachtenberg J, Magklara A, Scorilas A, Papnastasiou PA, Jewett MA, Narod SA. Serum human glandular kallikrein-2 protease levels predict the presence of prostate cancer among men with elevated prostate-specific antigen. J Clin Oncol 2000; 18:1036-42. [PMID: 10694554 DOI: 10.1200/jco.2000.18.5.1036] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE We hypothesize that serum human glandular kallikrein-2 (hK2) levels predict the presence of prostate cancer among men prescreened by prostate-specific antigen (PSA). PATIENTS AND METHODS We conducted a cross-sectional study of 324 men who had no history of prostate cancer and who were referred for prostate biopsy. PSA and hK2 levels were measured using specific nonisotopic immunometric techniques. Cases were patients who were diagnosed with adenocarcinoma of the prostate from biopsy, and controls were patients who had no evidence of cancer from biopsy. The odds ratio for detection of prostate cancer was determined for hK2 measurements, controlling for age, total-PSA level, digital rectal examination, and symptoms of urinary obstruction. RESULTS Of 324 men, 159 (49.1%) had cancer. Mean hK2 levels and hK2:free-PSA ratios were significantly higher in cases than in controls (1.18 v 0.53 ng/mL, respectively, for hK2, P =.0001; 1.17 v 0.62 for hK2:free-PSA ratio, P =.0001). The crude odds ratio for prostate cancer detection for patients in the highest quartile of hK2 level was 5.83 (95% confidence interval [CI], 2.8 to 12.1; P =.0001) compared with patients in the lowest quartile. The adjusted odds ratio was 6.72 (95% CI, 2.9 to 15.6; P =.0001). Similarly, the crude and adjusted odds ratios for prostate cancer detection using the hK2:free-PSA ratio were 7.36 (95% CI, 3.6 to 15.1; P =.0001) and 8.06 (95% CI, 3. 7 to 17.4; P =.0001), respectively. These odds ratios were higher than that observed for prostate cancer detection by total-PSA level (2.73; P =.03). CONCLUSION Among men prescreened with PSA for prostate cancer, patients with high hK2 measurements have a five- to eight-fold increase in risk for prostate cancer, adjusting for PSA level and other established risk factors. hK2 measurements may be a useful adjunct to PSA in improving patient selection for prostate biopsy.
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Affiliation(s)
- R K Nam
- Division of Urology, Department of Diagnostic Imaging, Princess Margaret Hospital, University Health Network, University of Toronto, Ontario, Canada
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29
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Wright GL, Beckett ML, Newhall KR, Adam BL, Cazares LH, Cartwright SL, Xiao Z, Gong L, Schellhammer PF. Identification of a superimmunoglobulin gene family member overexpressed in benign prostatic hyperplasia . Prostate 2000; 42:230-8. [PMID: 10639194 DOI: 10.1002/(sici)1097-0045(20000215)42:3<230::aid-pros9>3.0.co;2-j] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Benign prostate hyperplasia (BPH), a nonmalignant disease with an increasing rate of occurrence associated with advancing age, requires auxiliary markers to help identify its presence and distinguish its progression from prostate cancer. METHODS Hybridoma technology was used to generate an antibody against a BPH antigen, which was subsequently characterized by Western blot analysis, sequence homology, and RT-PCR. RESULTS A BPH-associated protein, designated P25/26, was identified that showed a strong sequence similarity with superimmunoglobulin family members, overexpressed in BPH, with lower expression observed in both normal and prostate cancer tissues. CONCLUSIONS Further studies appear warranted to assess the role that this and other superimmunoglobulin family members may have in the pathogenesis of BPH, and to determine if these glycoproteins have any clinical utility in the differential diagnosis or therapeutic monitoring of BPH.
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Affiliation(s)
- G L Wright
- Departments of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia 23501, USA.
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30
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Becker C, Piironen T, Kiviniemi J, Lilja H, Pettersson K. Sensitive and Specific Immunodetection of Human Glandular Kallikrein 2 in Serum. Clin Chem 2000. [DOI: 10.1093/clinchem/46.2.198] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractBackground: Human glandular kallikrein 2 (hK2) is expressed in the prostate and is present in serum from men with prostate cancer. Specific detection in serum is difficult mainly because of low concentrations and immunological cross-reactivity with prostate-specific antigen (PSA). Our objectives were to design an assay with improved analytical detection and functional sensitivity and nonsignificant cross-reactivity with PSA, and to characterize different immunoreactive forms of hK2.Methods: In the assay, critical PSA epitopes were blocked with four monoclonal antibodies (MAbs) specific for PSA. Subsequently, hK2 was captured using a MAb against hK2 (5% cross-reactivity with PSA), and after washing, hK2 was detected by a europium-labeled MAb with identical affinity for hK2 and PSA.Results: The analytical detection limit was <10 ng/L, and functional sensitivity was 30 ng/L. Cross-reaction with PSA was <0.01%. Between-assay imprecision was 3.1% for 1600 ng/L hK2 and 4.8% for 160 ng/L hK2; corresponding values for within-assay precision were 1.9% and 4.5%, respectively. Complexes of hK2-α1-antichymotrypsin (ACT) were detected in vitro with −6% bias compared with the free form of hK2. Gel filtration of patient samples showed that hK2 correlated in size mainly with free hK2; only 4–19% corresponded to hK2 possibly complexed with ACT or protein C inhibitor.Conclusions: Our assay had extremely low cross-reactivity with PSA, provided a very low detection limit, and allowed close to equimolar detection of the free and complexed forms of hK2. Moreover, we found that free hK2 is the predominant immunoreactive form of hK2 in serum.
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Affiliation(s)
- Charlotte Becker
- Department of Clinical Chemistry, Lund University, University Hospital Malmö, S-205 02 Malmö, Sweden
| | - Timo Piironen
- Department of Biotechnology, Turku University, 20520 Turku, Finland
| | | | - Hans Lilja
- Department of Clinical Chemistry, Lund University, University Hospital Malmö, S-205 02 Malmö, Sweden
| | - Kim Pettersson
- Department of Biotechnology, Turku University, 20520 Turku, Finland
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Black MH, Magklara A, Obiezu C, Levesque MA, Sutherland DJ, Tindall DJ, Young CY, Sauter ER, Diamandis EP. Expression of a prostate-associated protein, human glandular kallikrein (hK2), in breast tumours and in normal breast secretions. Br J Cancer 2000; 82:361-7. [PMID: 10646889 PMCID: PMC2363279 DOI: 10.1054/bjoc.1999.0927] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recent demonstration of human glandular kallikrein (hK2) expression in a breast carcinoma cell line has suggested that this putatively prostate-restricted, steroid hormone-regulated protease may also be expressed in breast epithelium in vivo and secreted into the mammary duct system. Given that the only substrate yet identified for hK2 activity is the precursor of prostate-specific antigen (PSA), the expression of which in breast carcinomas may be associated with favourable prognosis, our purpose was to examine the expression pattern of both hK2 and PSA in breast tumour tissues. Cytosolic extracts of 336 primary breast carcinomas prepared for routine oestrogen receptor (ER) and progesterone receptor (PR) analysis, as well as 31 nipple aspirates from six women with non-diseased mammary glands, were assayed for hK2 and PSA using immunofluorometric assays developed by the authors. In the tumour extracts, measurable hK2 and PSA concentrations were detected in 53% and 73% of cases respectively, and were positively correlated to each other (r = 0.59, P = 0.0001). Higher concentrations of PSA and hK2 were found in tumours expressing steroid hormone receptors (P = 0.0001 for PSA and P = 0.0001 for hK2, by Wilcoxon tests for both ER and PR), and both PSA (r = 0.25, P = 0.0001) and hK2 (r = 0.22, P = 0.0001) correlated directly with PR levels. A negative correlation between patient age and PSA (r = -0.12, P = 0.03) was also found. Both proteins were present in nipple aspirate fluid at relatively high concentrations which were positively correlated (r = 0.53, P = 0.002). The molecular weights of the immunoreactive species quantified by the hK2 and PSA assays were established by high-performance liquid chromatography (HPLC) and were consistent with the known molecular weights of hK2 and PSA. Together these data provide the first evidence, to our knowledge, that both malignant breast tissue and normal breast secretion contain measurable quantities of hK2, and that the degree of hK2 expression or secretion is directly proportional to the expression of PSA and steroid hormone receptors. hK2 expression may therefore be a marker of steroid hormone action in breast tissue.
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Affiliation(s)
- M H Black
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
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Abstract
Benign prostatic hyperplasia is a common condition in males over 50 years, but prostate cancer can develop in the same population. Prostate specific antigen, the best marker for prostate cancer, is also produced by benign epithelial cells, and there is an overlapping phenomenon between both conditions. The better we understand the relationships between benign prostatic hyperplasia and prostate specific antigen, the higher will be the discrimination power of prostate specific antigen measurement as a marker for prostate cancer. Our scope includes a review of the latest published material to date on this subject.
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Affiliation(s)
- P Laguna
- Urology Department, Hospital Gral. La Mancha-Centro Hospital, Alcazar de San Juan, Spain.
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33
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Magklara A, Scorilas A, Catalona WJ, Diamandis EP. The Combination of Human Glandular Kallikrein and Free Prostate-specific Antigen (PSA) Enhances Discrimination Between Prostate Cancer and Benign Prostatic Hyperplasia in Patients with Moderately Increased Total PSA. Clin Chem 1999. [DOI: 10.1093/clinchem/45.11.1960] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Background: Prostate-specific antigen (PSA) is the most reliable tumor marker available and is widely used for the diagnosis and management of prostate cancer. Unfortunately, PSA cannot distinguish efficiently between benign and malignant disease of the prostate, especially within the range of 4–10 μg/L. Among the refinements developed to enhance PSA specificity is the free/total PSA ratio, which is useful in discriminating between the two diseases within the diagnostic “gray zone”. Recent data indicate that human glandular kallikrein (hK2), a protein with high homology to PSA, may be an additional serum marker for the diagnosis and monitoring of prostate cancer.
Methods: We analyzed 206 serum samples (all before treatment was initiated) from men with histologically confirmed benign prostatic hyperplasia (n = 100) or prostatic carcinoma (n = 106) with total PSA in the range of 2.5–10 μg/L. Total and free PSA and hK2 were measured with noncompetitive immunological procedures. Statistical analysis was performed to investigate the potential utility of the various markers or their combinations in discriminating between benign prostatic hyperplasia and prostatic carcinoma.
Results: hK2 concentrations were not statistically different between the two groups of patients. There was a strong positive correlation between hK2 and free PSA in the whole patient population. hK2/free PSA ratio (area under the curve = 0.69) was stronger predictor of prostate cancer than the free/total PSA ratio (area under the curve = 0.64). At 95% specificity, the hK2/free PSA ratio identified 30% of patients with total PSA between 2.5–10 μg/L who had cancer. At 95% specificity, the hK2/free PSA ratio identified 25% of patients with total PSA between 2.5 and 4.5 μg/L who had cancer.
Conclusions: Our data suggest that hK2 in combination with free and total PSA can enhance the biochemical detection of prostate cancer in patients with moderately increased total PSA concentrations. More specifically, the hK2/free PSA ratio appears to be valuable in identifying a subset of patients with total PSA between 2.5 and 4.5 μg/L who have high probability of cancer and who should be considered for biopsy.
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Affiliation(s)
- Angeliki Magklara
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Andreas Scorilas
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - William J Catalona
- Division of Urologic Surgery, Department of Surgery, Washington University School of Medicine, St. Louis, MO 63110
| | - Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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34
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Partin AW, Catalona WJ, Finlay JA, Darte C, Tindall DJ, Young CY, Klee GG, Chan DW, Rittenhouse HG, Wolfert RL, Woodrum DL. Use of human glandular kallikrein 2 for the detection of prostate cancer: preliminary analysis. Urology 1999; 54:839-45. [PMID: 10565744 DOI: 10.1016/s0090-4295(99)00270-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES Human glandular kallikrein 2 (hK2) and prostate-specific antigen (PSA) are members of a multigene family of serine proteases that share approximately 80% sequence homology. Both are expressed in the prostate epithelium, are under androgen regulation, are present in serum and seminal fluid, and can form complexes with endogenous protease inhibitors (eg, alpha2-macroglobulin and alpha1-antichymotrypsin). Differences in immunohistochemistry and substrate specificity suggest hK2 may provide unique information for early detection and characterization of prostate cancer. METHODS Nine hundred thirty-seven archived serum samples from men treated at two academic institutions were studied. All men underwent biopsy, had a histologically confirmed diagnosis of cancer or noncancer, and a total PSA level greater than 2 ng/mL. Samples were tested in Hybritech's Tandem-R PSA and Tandem-R free PSA (fPSA) assays and a research prototype assay for total hK2 (thK2). RESULTS The thK2/fPSA ratio provided additional specificity for cancer detection over PSA and the percentage of fPSA (%fPSA). A model for cancer detection using %fPSA and the thK2/fPSA ratio when PSA is 2 to 4 ng/mL is proposed that would identify as many as 40% of the cancers and would require biopsy in only 16.5% of the men in this PSA range. CONCLUSIONS In this study, %fPSA and thK2/fPSA provided unique information for prostate cancer detection and increased the specificity of cancer detection.
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Affiliation(s)
- A W Partin
- Department of Urology, Johns Hopkins Hospital, Baltimore, Maryland, USA
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35
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Magklara A, Scorilas A, López-Otín C, Vizoso F, Ruibal A, Diamandis EP. Human Glandular Kallikrein in Breast Milk, Amniotic Fluid, and Breast Cyst Fluid. Clin Chem 1999. [DOI: 10.1093/clinchem/45.10.1774] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background: Human glandular kallikrein (hK2) belongs to the serine protease family of enzymes and has high sequence homology with prostate-specific antigen (PSA). The physiological role of hK2 has not as yet been determined, but there is evidence that it can regulate the proteolytic activity of PSA through processing and activating pro-PSA, an inactive precursor. Thus, it is conceivable that these two secreted proteins may coexist in biological fluids. Currently, hK2 is considered an androgen-regulated and prostate-specific protein. Recently, it has been demonstrated that hK2 is expressed in the breast cancer cell line T-47D after stimulation by steroid hormones, and we reported that hK2 can be detected in a subset of breast tumor extracts. These data suggest that hK2 may be expressed in tissues other than the prostate, such as those in which PSA has already been detected. Because hK2 is a secreted protein, it may be present in various biological fluids.
Methods: We analyzed milk samples from lactating women, amniotic fluid from pregnant women, and breast cyst fluid from patients with gross breast cystic disease, using a highly sensitive and specific immunoassay for hK2.
Results: hK2 was present in all three biological fluids. We suggest that the female breast may produce hK2 and provide evidence that hK2 may have value as an additional marker for the discrimination between type I and type II breast cysts.
Conclusions: The female breast produces hK2 in addition to PSA. More studies are necessary to establish the role of this kallikrein in nondiseased breast, gross breast cystic disease, and breast cancer.
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Affiliation(s)
- Angeliki Magklara
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
| | - Andreas Scorilas
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
| | - Carlos López-Otín
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Oviedo, Oviedo, Spain
| | | | | | - Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5, and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
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Theyer G, Dürer A, Theyer U, Haberl I, Ulsperger E, Baumgartner G, Hamilton G. Measurements of free and total PSA, tissue polypeptide-specific antigen (TPS), and CYFRA 21-1 in prostate cancer patients under intermittent androgen suppression therapy. Prostate 1999; 41:71-7. [PMID: 10477903 DOI: 10.1002/(sici)1097-0045(19991001)41:2<71::aid-pros1>3.0.co;2-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The present study evaluated monthly measurements of free and total prostate-specific antigen (PSA), and the tumor proliferation markers tissue polypeptide-specific antigen (TPS) and cytokeratin fragment 21-1 (CYFRA 21-1) in patients with advanced prostate cancer receiving intermittent androgen suppression therapy (IAS). METHODS Thirty-four men received alternating cycles of 8 month androgen suppression and treatment cessation (mean duration, 10.3 months) until PSA increased to >20 microg/l. Measurements of testosterone, percentage of free PSA, TPS, and CYFRA 21-1 were performed using ELISA and RIA assays. RESULTS Periods of androgen suppression resulted in reversible reductions of testosterone (from 6 +/- 0.8 to <0.58 ng/ml), PSA (from 31.2 +/- 4.5 to <1.7 microg/l), and prostatic volume (mean reduction, 22.2 +/- 4.6%), indicating apoptotic regression of the tumors. Upon treatment cessation, testosterone increased to 6.1 +/- 0.56 ng/ml within 2 months, followed by an increase of PSA to 5.8 +/- 0.8 microg/l. The mean percentage of free PSA (15.1 +/- 2.6%) exhibited no significant change during the whole IAS cycle. TPS showed a decrease of 50% after 3 months, and CYFRA 21-1 a 25% decrease after 7 months of androgen suppression treatment. During treatment cessation, TPS exceeded the normal cutoff value of 90 U/l late in tumor regrowth (9-11 months), whereas CYFRA 21-1 remained below the normal cutoff value of 3.3 ng/ml. CONCLUSIONS PSA is the best and most sensitive marker of prostate cancer regression and regrowth during IAS cycles of the markers tested in this study. Free PSA constitutes approximately 15% of total PSA (range, 5-32%), and its percentage showed no significant change during IAS cycles. The TPS and CYFRA 21-1 proliferation marker changes in IAS seem to be related mainly to effects on normal androgen-dependent tissues.
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Affiliation(s)
- G Theyer
- Department of Urology, Wilhelminenspital der Stadt Wien, Vienna, Austria
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37
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Tazawa K, Kurihara Y, Kamoshida S, Tsukada K, Tsutsumi Y. Localization of prostate-specific antigen-like immunoreactivity in human salivary gland and salivary gland tumors. Pathol Int 1999; 49:500-5. [PMID: 10469392 DOI: 10.1046/j.1440-1827.1999.00900.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Immunoreactivity of prostate-specific antigen (PSA), a kallikrein-like enzyme present in the seminal plasma, was demonstrated by indirect immunoperoxidase staining using a PSA antiserum in the apical cytoplasm along the luminal border of small-sized duct epithelial cells of the major salivary (parotid and submandibular) gland of both sexes (56/56, 100%). No PSA-like immunoreactivity was seen in large-sized duct epithelial cells and acinar cells. Minor salivary gland ducts were negative. When inflammatory and atrophic changes were observed, ductal expression of PSA-like immunoreactivity was decreased (12/37, 32%) and the site of intracellular localization often became diffusely cytoplasmic. The immunoreactivity was absorbed by human seminal plasma. Immunoreactivities of prostatic acid phosphatase and sex hormone receptors were undetectable in the salivary gland. Twenty-nine (34%) of 86 salivary gland tumors with ductal differentiation were immunoreactive for PSA mainly in the cytoplasm. A PSA monoclonal antibody ER-PR8 detected immunoreactivity in the prostate but not in the salivary glands or their tumors. Prostate-specific antigen-like immunoreactivity in small-sized (intercalated) duct epithelial cells of the major salivary gland and their tumors may be due to cross-reactivity of the antiserum with kallikrein-like substances.
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Affiliation(s)
- K Tazawa
- Department of Pathology, Tokai University School of Medicine, Bohseidai, Isehara, Japan
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38
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Klee GG, Goodmanson MK, Jacobsen SJ, Young CYF, Finlay JA, Rittenhouse HG, Wolfert RL, Tindall DJ. Highly Sensitive Automated Chemiluminometric Assay for Measuring Free Human Glandular Kallikrein-2. Clin Chem 1999. [DOI: 10.1093/clinchem/45.6.800] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background: Human glandular kallikrein (hK2) is a serine protease that has 79% amino acid identity with prostate-specific antigen (PSA). Both free hK2 and hK2 complexed to α1-antichymotrypsin (ACT) are present in the blood in low concentrations. We wished to measure hK2 in serum with limited contribution from hK2-ACT for the results.
Methods: We developed an automated assay for hK2 with use of a select pair of monoclonal antibodies. The prototype assay was implemented on a Beckman Coulter ACCESS® analyzer.
Results: The detection limit of the assay was 1.5 ng/L, the “functional sensitivity” (day-to-day CV <15%) was <4 ng/L, cross-reactivity with PSA and PSA-ACT was negligible, and cross-reactivity with hK2-ACT was 2%. After surgical removal of prostate glands, serum hK2 was <7 ng/L and was <15 ng/L in most healthy women. The median serum concentration of hK2 in healthy men without prostate cancer was 26 ng/L. The median concentration of hK2 was 72 ng/L for men having prostate cancer with lower Gleason scores compared with 116 ng/L for men with more advanced cancer. The concentration of hK2 correlated weakly with PSA, with the mean hK2 concentrations generally 30- to 80-fold lower than PSA concentrations.
Conclusion: The availability of a robust, high sensitivity automated assay for hK2 should facilitate further investigations of the role of hK2 measurements in the management of patients with prostate disease.
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Affiliation(s)
| | | | | | - Charles YF Young
- Urology Research, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905
| | - Judith A Finlay
- Department of Research and Development, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Harry G Rittenhouse
- Department of Research and Development, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Robert L Wolfert
- Department of Research and Development, Hybritech Inc., a subsidiary of Beckman Coulter, Inc., San Diego, CA 92121
| | - Donald J Tindall
- Urology Research, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905
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39
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Black MH, Magklara A, Obiezu CV, Melegos DN, Diamandis EP. Development of an Ultrasensitive Immunoassay for Human Glandular Kallikrein with No Cross-Reactivity from Prostate-specific Antigen. Clin Chem 1999. [DOI: 10.1093/clinchem/45.6.790] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Background: Studies demonstrating that human glandular kallikrein (hK2) is increased in prostate cancer patients have prompted speculation that this marker may of use in addition to prostate-specific antigen (PSA).
Methods: An ultrasensitive hK2 sandwich immunoassay was developed, and its detection limit, cross-reactivity, analytical recovery, precision, and linearity of dilution were evaluated. hK2 was measured in seminal plasma and sera from healthy males, females, and prostatectomized patients.
Results: Our assay has an excellent detection limit (6 ng/L) and precision (>90%). Recovery studies indicated that hK2 binds to serum protease inhibitors. All sera from healthy males had measurable hK2 concentrations (median, 402 ng/L). Almost all female sera had undetectable hK2. Serum hK2 and PSA in males correlated positively (r = 0.44), but hK2 was present at concentrations ∼2.5-fold lower than PSA. The PSA/hK2 ratio in male sera was 0.1–34, with a median of 2.6. In seminal plasma, this ratio was 100–500. More than 94% of immunoreactive hK2 in serum was in the free form (∼30 kDa); traces of hK2 complexed to α1-antichymotrypsin were present.
Conclusions: The limit of detection of the method for hK2 measurement described here (∼20-fold lower than any other reported assay for hK2) allows the generation of new clinical information. When combined with a previously described method for PSA measurement that has no cross-reactivity from hK2, this methods allows the relative proportions of hK2 and PSA in biological fluids to be measured.
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Affiliation(s)
- Margot H Black
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
| | - Angeliki Magklara
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
| | - Christina V Obiezu
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
| | - Dimitrios N Melegos
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
| | - Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1L5
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40
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Mikolajczyk SD, Millar LS, Kumar A, Saedi MS. Prostatic human kallikrein 2 inactivates and complexes with plasminogen activator inhibitor-1. Int J Cancer 1999; 81:438-42. [PMID: 10209959 DOI: 10.1002/(sici)1097-0215(19990505)81:3<438::aid-ijc18>3.0.co;2-u] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Human kallikrein 2 (hK2) is a serine protease expressed predominantly in the prostate which has 80% homology to prostate-specific antigen (PSA). hK2 is an active trypsin-like protease which has been shown by immuno-histochemical staining to be more highly expressed in prostate carcinoma than in benign prostate tissue. Unlike PSA, hK2 activates pro-PSA , pro-hK2 and the zymogen form of urokinase-type plasminogen activator (uPA), an extracellular protease correlated with prostate cancer and metastasis. We show here that hK2 rapidly forms a complex with plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor of uPA in tissues. In addition, hK2 inactivated 6 to 7 mol of PAI-1 by cleavage at Arg346-Met347 for every mole of hK2-PAI-1 complex formed. In contrast with hK2, PSA neither complexed with nor inactivated PAI-1. PAI-1 inhibited hK2 comparably with protein C inhibitor (PCI) and at least 20 times more rapidly than alpha1-anti-chymotrypsin (ACT). N-Terminal sequencing shows that hK2 forms a covalent complex with PAI-1, PCI and ACT after cleavage at Arg346-Met347, Arg354-Ser355 and Leu358-Ser359, respectively. During complex formation, hK2 inactivated PAI-1 but did not inactivate ACT or PCI. Our current results suggest that the increased hK2 expression in prostate cancer tissues could influence cancer biology not only by activation of uPA but also by inactivation of its primary inhibitor, PAI-1.
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Affiliation(s)
- S D Mikolajczyk
- Hybritech Incorporated, a subsidiary of Beckman Coulter Inc., San Diego, CA 92196-9006, USA.
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41
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Darson MF, Pacelli A, Roche P, Rittenhouse HG, Wolfert RL, Saeid MS, Young CY, Klee GG, Tindall DJ, Bostwick DG. Human glandular kallikrein 2 expression in prostate adenocarcinoma and lymph node metastases. Urology 1999; 53:939-44. [PMID: 10223487 DOI: 10.1016/s0090-4295(98)00637-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To describe the expression of a potential new tumor marker, human glandular kallikrein 2 (hK2), in primary adenocarcinoma and lymph node metastases that may be useful as an adjunct to prostate-specific antigen (PSA) in the diagnosis and monitoring of prostate cancer. METHODS We evaluated 151 radical prostatectomy specimens removed at Mayo Clinic with node-positive adenocarcinoma to compare cytoplasmic expression of hK2, pro-hK2, and PSA in benign tissue, prostate adenocarcinoma, and lymph node metastases. Monoclonal antibodies for mature hK2 (hK2-G586), pro-hK2 (pro-hK2-G464), and PSA (PSA-773) were used. A polyclonal antibody for PSA was also used. Immunoreactivity in each case was tested to determine whether cancer recurrence could be predicted. RESULTS Intense epithelial cytoplasmic immunoreactivity was observed in every case for hK2-G586, pro-hK2-G464, PSA-773, and polyclonal PSA (100% of cases, respectively). The intensity and extent of hK2 expression was greater in lymph node metastases than in primary cancer; furthermore, the expression in primary cancer was greater than in benign epithelium. Pro-hK2 was expressed in a greater percentage of cells in primary cancer than in benign tissue; furthermore, pro-hK2 was expressed to a greater extent in primary cancer than in lymph node metastases. In marked contrast to mature hK2, monoclonal PSA immunoreactivity was expressed to a higher extent in primary cancer than in lymph node metastases. Polyclonal PSA showed an incremental increase in expression from benign tissue to primary cancer and a further increase in expression in lymph node metastases. CONCLUSIONS hK2 was expressed in every cancer, and the expression incrementally increased from benign epithelium to primary cancer and lymph node metastases. Pro-hK2 was expressed to the greatest extent in primary cancer. Monoclonal PSA displayed inverse immunoreactivity compared with hK2. Polyclonal PSA showed incremental increases, suggesting that both hK2 and PSA were being detected. Tissue expression of hK2 appears to be regulated independently of PSA in benign epithelium, adenocarcinoma, and lymph node metastases.
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Affiliation(s)
- M F Darson
- Department of Urology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA
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Black MH, Grass CL, Leinonen J, Stenman UH, Diamandis EP. Characterization of Monoclonal Antibodies for Prostate-specific Antigen and Development of Highly Sensitive Free Prostate-specific Antigen Assays. Clin Chem 1999. [DOI: 10.1093/clinchem/45.3.347] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Background: The recent elucidation of the importance of serological free prostate-specific antigen (PSA) in the diagnosis of prostate cancer has created a demand for immunoassays specific for free PSA.
Methods: We developed and characterized 11 monoclonal antibodies with high affinities for PSA (Kavalues from 1.1 × 108 to 1.8 × 1010L/mol), only 3 of which cross-react with human glandular kallikrein (hK2). Using these antibodies and PSA antibodies developed by others, in conjunction with time-resolved fluorometry, we developed ultrasensitive sandwich immunoassays specific for the free form of PSA.
Results: The analytical detection limit of these immunoassays is 0.001 μg/L. To our knowledge, this is the most sensitive free PSA assay reported to date. The free PSA immunoassays exhibit <1% cross-reactivity with PSA-α1-antichymotrypsin, show no cross-reactivity with hK2, and correlate well with established free PSA kits. The 11 antibodies developed by our group, in conjunction with 4 commercially available antibodies, were used to generate a putative epitope map of the PSA molecule.
Conclusion: The highly sensitive free PSA immunoassays may be used for measuring PSA subfractions in female serum, an application currently impossible with other reported free PSA immunoassays.
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Affiliation(s)
- Margot H Black
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1X5
| | - C Linda Grass
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5
| | - Jari Leinonen
- Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland
| | - Ulf-Håkan Stenman
- Department of Clinical Chemistry, Helsinki University Central Hospital, Helsinki, Finland
| | - Eleftherios P Diamandis
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada M5G 1X5
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Kumar A, Goel AS, Payne JK, Evans C, Mikolajczyk SD, Kuus-Reichel K, Saedi MS. Large-scale propagation of recombinant adherent cells that secrete a stable form of human glandular kallikrein, hK2. Protein Expr Purif 1999; 15:62-8. [PMID: 10024471 DOI: 10.1006/prep.1998.0998] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human glandular kallikrein 2 (hK2) is a trypsin-like serine protease that is expressed predominantly in the prostate epithelium and has 78% aa identity with prostate-specific antigen (PSA). hK2 has been recognized as a potential prostate cancer marker and has been demonstrated to be highly expressed in prostate cancer compared to benign prostatic tissue. Purification and characterization of hK2 have been impeded due to its lower expression in bodily fluids and tissues compared to PSA and its ability to autodegrade. Therefore, to study biochemical and biological characteristics of hK2, a stable and enzymatically inactive mutant form of hK2, hK2(A217V), was expressed in a hamster cell line, AV12-664 (AV12-hK2(A217V)). AV12-hK2(A217V) cells secreted prohK2(A217V) (phK2(A217V)) in the spent medium at approximately 2.5 microgram/ml. Since AV12-hK2(A217V) are adherent cells, it was necessary to develop an efficient system to propagate large numbers of cells to obtain significant quantities of phK2(A217V). In this paper, we compared ceramic core bioreactor and microcarrier beads as alternatives to static culture to propagate adherent cells. Considering production levels, ease of operation, cost effectiveness, and labor, microcarrier beads were found to be a better alternative. Our findings led to the development of a general protocol for large-scale propagation of adherent cells on microcarrier beads eliminating the need for propagating AV12-hK2(A217V) in culture flasks or bioreactors. Microcarrier beads coated with AV12-hK2(A217V) cells could be propagated in 1- or 3-liter spinner flasks and were passed from one spinner to the next in a manner analogous to static culture or could be frozen and later used as inoculum for subsequent spinners. Using this protocol, >40 liters of spent medium was harvested within 30 days, which in turn was used to purify phK2(A217V). phK2(A217V) purified from spent medium of cells grown either on microcarrier beads or in culture flasks were biochemically similar as indicated by HIC-HPLC profile followed by sequencing of relevant peaks.
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Affiliation(s)
- A Kumar
- a subsidiary of Beckman Coulter, Inc., San Diego, California, 92196-9006, USA
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Heeb MJ, España F. alpha2-macroglobulin and C1-inactivator are plasma inhibitors of human glandular kallikrein. Blood Cells Mol Dis 1998; 24:412-9. [PMID: 9851894 DOI: 10.1006/bcmd.1998.0209] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human glandular kallikrein (hK2) is a possible new marker for prostate cancer that is homologous to prostate specific antigen. Purified hK2 added to serum or plasma reacted with endogenous protease inhibitors to form complexes of >350, 135, and 80 kDa, and some hK2 remained free, as judged by immunoblotting. The former two complexes could be removed by specific antibodies to alpha2-macroglobulin and to C1- inactivator, respectively, and they comigrated on SDS-PAGE with complexes formed between hK2 and purified alpha2-macroglobulin or C1-inactivator. hK2 complexes of 80 kDa could not be completely removed with any anti-serpin antibody used. Thus, these may consist of more than one type of hK2 complex. In contrast, essentially all hK2 complexes were removed from seminal plasma by antibody to protein C inhibitor, demonstrating that protein C inhibitor is the only significant inhibitor of hK2 in semen. hK2 reacted more rapidly with alpha2-macroglobulin than with any other inhibitor in plasma or serum. Divalent metal ions and heparin did not appreciably affect the rate of formation of any of the hK2 complexes in serum or plasma or with purified alpha2-macroglobulin or C1-inactivator. Measurement of one or more of the hK2 forms identified here may have diagnostic or prognostic potential for prostate cancer.
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Affiliation(s)
- M J Heeb
- Departments of Molecular and Experimental Medicine and of Vascular Biology, The Scripps Research Institute, La Jolla, CA.
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Rittenhouse HG, Finlay JA, Mikolajczyk SD, Partin AW. Human Kallikrein 2 (hK2) and prostate-specific antigen (PSA): two closely related, but distinct, kallikreins in the prostate. Crit Rev Clin Lab Sci 1998; 35:275-368. [PMID: 9759557 DOI: 10.1080/10408369891234219] [Citation(s) in RCA: 227] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Recent studies on human kallikrein 2 (hK2) have revealed striking similarities and significant differences with the closely related kallikrein PSA. Both PSA and hK2 are primarily localized to the prostate and share close structural similarities. Although both kallikreins are produced by the same secretory epithelial cells in the prostate, hK2 is associated more with prostate tumors than PSA and is highly expressed in poorly differentiated cancer cells. The potent trypsin-like activity of hK2 contrasts with the weak chymotrypsin-like activity of PSA. The inactive precursor form of PSA, proPSA, is converted rapidly to active PSA by hK2, suggesting an important in vivo regulatory function by hK2 on PSA activity. The high homology between hK2 and PSA results in significant cross-reactivity to hK2 by polyclonal and some monoclonal antibodies to PSA. Future studies on both PSA and hK2 need to take into account this potential for cross-reactivity. Specific monoclonal antibodies to hK2 have now demonstrated that serum levels of hK2, like PSA, are correlated with prostate cancer. The production of hK2 protein in active protease form and specific monoclonal antibodies to the hK2 antigen will allow extensive future studies delineating the physiological and clinical utility of this new prostate antigen.
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Affiliation(s)
- H G Rittenhouse
- Research and Development Department, Hybritech Incorporated, Beckman Coulter, Inc., San Diego, California, USA.
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