| 1. |
- Stenman, U H, et al.
(author)
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Summary report of the TD-3 workshop: characterization of 83 antibodies against prostate-specific antigen
- 1999
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In: Tumor Biology. - : Springer Science and Business Media LLC. - 1423-0380 .- 1010-4283. ; 20:Suppl. 1, s. 1-12
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Journal article (peer-reviewed)abstract
- Twelve research groups participated in the ISOBM TD-3 Workshop in which the reactivity and specificity of 83 antibodies against prostate-specific antigen (PSA) were investigated. Using a variety of techniques including cross-inhibition assays, Western blotting, BIAcore, immunoradiometric assays and immunohistochemistry, the antibodies were categorized into six major groups which formed the basis for mapping onto two- and three-dimensional (2-D and 3-D) models of PSA. The overall findings of the TD-3 Workshop are summarized in this report. In agreement with all participating groups, three main antigenic domains were identified: free PSA-specific epitopes located in or close to amino acids 86-91; discontinuous epitopes specific for PSA without human kallikrein (hK2) cross-reactivity located at or close to amino acids 158-163; and continuous or linear epitopes shared between PSA and hK2 located close to amino acids 3-11. In addition, several minor and partly overlapping domains were also identified. Clearly, the characterization of antibodies from this workshop and the location of their epitopes on the 3-D model of PSA illustrate the importance of selecting appropriate antibody pairs for use in immunoassays. It is hoped that these findings and the epitope nomenclature described in this TD-3 Workshop are used as a standard for future evaluation of anti-PSA antibodies.
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| 2. |
- Pettersson, K, et al.
(author)
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Free and complexed prostate-specific antigen (PSA) : in vitro stability, epitope map, and development of immunofluorometric assays for specific and sensitive detection of free PSA and PSA-alpha 1-antichymotrypsin complex
- 1995
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In: Clinical Chemistry. - 0009-9147. ; 41:10, s. 8-1480
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Journal article (peer-reviewed)abstract
- Generation of 15 monoclonal antibodies (MAbs) allowed construction of epitope maps and specific two-site immunofluorometric assays for free prostate-specific antigen (PSA) and PSA complexed with alpha 1-antichymotrypsin (ACT). Close correlation of PSA concentrations obtained with the use of different assays of free PSA suggested extensive similarity in immunodetection of free PSA in serum. Assays of the PSA-ACT complex overestimated the concentration of PSA-ACT in serum because of nonspecific adsorbance of ACT or cathepsin G-complexed ACT to the solid phase. This interference was substantially decreased in the presence of heparin. In studying the stability of purified PSA and PSA-ACT complexes formed in vitro, we found that the free PSA was stable during storage for 4 weeks at 35 degrees C, whereas PSA-ACT complexes largely dissociated in these conditions. The instability of PSA-ACT complexes was counteracted by storage at low temperatures, by adjusting the pH of the storage buffer between 6.8 and 7.4, and through addition of 100-1000-fold molar excess of native ACT. The ease of calibration and the accuracy of free PSA assays in comparison with assays of the PSA-ACT complex suggest that measurements of free to total PSA most accurately reflect the inverse of the proportion of PSA complexed to ACT in serum.
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| 3. |
- Piironen, T, et al.
(author)
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Determination and analysis of antigenic epitopes of prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2) using synthetic peptides and computer modeling
- 1998
-
In: Protein Science. - : Wiley. - 1469-896X .- 0961-8368. ; 7:2, s. 259-269
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Journal article (peer-reviewed)abstract
- Prostate specific antigen (PSA) and human glandular kallikrein 2 (hK2), produced essentially by the prostate gland, are 237-amino acid monomeric proteins, with 79% identity in primary structure. Twenty-five anti-PSA monoclonal antibodies (Mabs) were studied for binding to a large array of synthetic linear peptides selected from computer models of PSA and hK2, as well as to biotinylated peptides covering the entire PSA sequence. Sixteen of the Mabs were bound to linear peptides forming four independent binding regions (I-IV). Binding region I was localized to amino acid residues 1-13 (identical sequence for PSA and hK2), II (a and b) was localized to residues 53-64, III (a and b) was localized to residues 80-91 (= kallikrein loop), and IV was localized to residues 151-164. Mabs binding to regions I and IIa were reactive with free PSA, PSA-ACT complex, and with hK2; Mabs binding to regions IIb, IIIa, and IV were reactive with free PSA and PSA-ACT complex, but unreactive with hK2; Mabs binding to region IIIb detected free PSA only. All Mabs tested (n = 7) specific for free PSA reacted with kallikrein loop (binding region IIIb). The presence of Mabs interacting with binding region I did not inhibit the catalytic activity of PSA, whereas Mabs interacting with other binding regions inhibited the catalysis. Theoretical model structures of PSA, hK2, and the PSA-ACT complex were combined with the presented data to suggest an overall orientation of PSA with regard to ACT.
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| 4. |
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| 5. |
- Becker, Charlotte, et al.
(author)
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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
- 2000
-
In: Urology. - 1527-9995. ; 55:5, s. 694-699
-
Journal article (peer-reviewed)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 Goteborg, 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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| 6. |
- Becker, Charlotte, et al.
(author)
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Discrimination of men with prostate cancer from those with benign disease by measurements of human glandular kallikrein 2 (HK2) in serum
- 2000
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In: Journal of Urology. - 1527-3792. ; 163:1, s. 311-316
-
Journal article (peer-reviewed)abstract
- PURPOSE: To investigate the clinical value of measuring human glandular kallikrein 2 (hK2) compared with free and total prostate specific antigen (PSA-F and PSA-T) in serum from patients with prostate disease. MATERIALS AND METHODS: Serum from healthy controls, from men with benign prostate hyperplasia (BPH), clinically localized prostate cancer (PCa), and advanced PCa were analyzed for hK2 (using an in-house-research assay with detection limit of 0.05 ng./mL and <0.1% cross-reaction with PSA) and for PSA-F and PSA-T (using the Dual Prostatus assay from EG&G Wallac). RESULTS: HK2 concentrations were <0.05 ng./mL in 50/50 healthy volunteers but significantly higher (p <0.0001) and > or =0.05 ng./mL in 28/54 (52%) patients with BPH. In comparison to these men, the hK2 levels were significantly higher (p <0.0001, median 0.085 ng./mL) and > or =0.05 ng./mL in 100/136 (74%) men with clinically localized PCa. Compared with localized PCa, the hK2 levels were significantly higher (p <0.0001, median 0.57 ng./mL) and > or =0.05 ng./mL in 55/57 (96%) patients with advanced PCa. The median hK2 levels ranged from 1.3 to 1.6% of those of PSA-T in all three patient groups, whereas percent hK2/PSA-F and hK2 x PSA-T/PSA-F levels were significantly higher in cancer patients compared with those with BPH. In the discrimination of clinically localized PCa from BPH, hK2 x PSA-T/PSA-F gave the largest area under the receiver operating curve (AUC = 0.81) and significantly (p = 0.025) larger AUC than PSA-T alone (0.70). Further, at 95% sensitivity there was significant gain in specificity, and at specificity levels of 90 to 95% there was significant gain in sensitivity using the measurements of PSA-T+PSA-F+hK2 compared with analysis of PSA-T and/or percent free PSA. CONCLUSIONS: Discrimination of patients with benign prostate disease from those with prostate cancer was significantly enhanced using measurements of hK2 in addition to those of PSA-T and PSA-F. Percent hK2/PSA-F was higher in PCa than in BPH, a phenomena not yet understood.
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| 7. |
- Becker, Charlotte, et al.
(author)
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Sensitive and specific immunodetection of human glandular kallikrein 2 in serum
- 2000
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In: Clinical Chemistry. - 0009-9147. ; 46:2, s. 198-206
-
Journal article (peer-reviewed)abstract
- BACKGROUND: 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-alpha(1)-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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| 8. |
- Björk, Thomas, et al.
(author)
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Rapid exponential elimination of free prostate-specific antigen contrasts the slow, capacity-limited elimination of PSA complexed to alpha 1-antichymotrypsin from serum
- 1998
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In: Urology. - 1527-9995. ; 51:1, s. 57-62
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Journal article (peer-reviewed)abstract
- OBJECTIVES: To study the rates of elimination of total prostate-specific antigen (PSA-T), free PSA (PSA-F), and PSA complexed to alpha 1-antichymotrypsin (PSA-ACT) from blood after radical retropubic prostatectomy (RRP). METHODS: We obtained venous blood from 10 patients with prostate cancer who were undergoing RRP. We analyzed PSA-F and PSA-ACT and equimolar detection of both of these forms together (PSA-T) by using immunofluorometric assays. An attempt was made to fit the serum concentrations of PSA-F, PSA-ACT, and PSA-T for each patient to exponential curves by applying one- and two-compartment models for pharmacokinetic analysis. RESULTS: Manipulation of the prostate during RRP resulted in a 3- to 28-fold increase in PSA-F concentrations in serum. Removal of the prostate resulted in a rapid, biexponential elimination of PSA-F from serum, corresponding to a mean initial (alpha) half-life of 0.81 hours and a mean terminal (beta) half-life of 13.9 hours. Serum PSA-ACT concentrations decreased by 20% to 40% immediately after removal of the gland; the elimination after surgery was slow and nonexponential, corresponding to a mean rate of 0.8 ng/mL/day. The elimination of PSA-T reflects a combination of the elimination patterns for PSA-F and PSA-ACT. CONCLUSIONS: The main proportion of PSA-F is rapidly eliminated from serum, possibly by glomerular filtration. PSA-F released during surgery did not form complexes with ACT, as suggested by the lack of PSA-ACT elevation in serum. The size (approximately 90 kDa) and the extensive in vitro stability of the PSA-ACT complex prevents renal clearance. The nonexponential elimination of the PSA-ACT complex is evidence of a capacity-limited process (e.g., metabolic transformation).
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| 9. |
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| 10. |
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| 11. |
- Erikson, A, et al.
(author)
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The near-Earth objects follow-up program - III. 3 lightcurves for 12 objects from 1992 and 1995
- 2000
-
In: ICARUS. - : ACADEMIC PRESS INC. - 0019-1035. ; 147:2, s. 487-497
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Journal article (peer-reviewed)abstract
- In this paper we present lightcurves and physical parameters for nine near-Earth objects (NEOs) (433 Eros, 1917 Cuyo, 2368 Beltrovata, 3753 Cruithne, 4769 Castalia, 4953 1990 MU, 6491 1991 OA, 1995 EK1, and 1995 FJ) and three Mars crossers (5738 Billpicke
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| 12. |
- Holten-Andersen, MN, et al.
(author)
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Measurement of the noncomplexed free fraction of tissue inhibitor of metalloproteinases I in plasma by immunoassay
- 2002
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In: Clinical Chemistry. - 0009-9147. ; 48:8, s. 1305-1313
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Journal article (peer-reviewed)abstract
- Background: We previously found differences in total concentrations of tissue inhibitor of metalloproteinases 1 (TIMP-1) in plasma from donors and cancer patients. Because TIMP-1 can exist in more than one molecular form, a new immunoassay to specifically detect free TIMP-1 was developed and concentrations were determined in plasma from healthy donors and colorectal cancer (CRC) patients. Methods: We established and validated an immunoassay for the specific measurement of free TIMP-1 that uses a polyclonal anti-TIMP-1 antibody for capture and a monoclonal anti-TIMP-1 antibody that binds only free TIMP-1 for detection of antigen. Plasma samples from healthy donors and CRC patients were assayed for free TIMP-1. Total TIMP-1 was measured by our previously published assay. Results: The mean (SD) concentrations of free TIMP-1 were similar in citrate [55.5 (11.5) mug/L] and EDTA plasma [58.9 (13.3) mug/L] from 76 donors (r(2) = 0.82). In 154 donors, the ratio of free TIMP-1 [mean (SD), 64.5 (18.0) mug/L] to total TIMP-1 [83.8 (19.8) mug/L] in EDTA plasma was 0.77. Plasma concentrations of free and total TIMP-1 correlated significantly to age (free, r(2) = 0.19; total, r(2) = .0.27; P < 0.0001), increasing 50% over an age span of 45 years. Free and total TIMP-1 were significantly increased in CRC patients (P < 0.0001), whereas the ratio of free to total TIMP-1 (mean, 0.58) was significantly lower than in donors. Conclusions: Most of the TIMP-1 in donor plasma is present in its free form, and free TIMP-1 increases with age. Free and total TIMP-1 are increased in CRC patient plasma, but the ratio of free to total TIMP-1 is significantly lower in these patients than in donors. (C) 2002 American Association for Clinical Chemistry.
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| 13. |
- Hutchings, Jeffrey A., et al.
(author)
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Life-history variability and conservation status of landlocked Atlantic salmon : an overview
- 2019
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In: Canadian Journal of Fisheries and Aquatic Sciences. - : Canadian Science Publishing. - 0706-652X .- 1205-7533. ; 76:10, s. 1697-1708
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Journal article (peer-reviewed)abstract
- Nonanadromous Atlantic salmon (Salmo salar) exhibit a combination of variation in life history, habitat, and species co-existence matched by few vertebrates. Distributed in eastern North America and northern Europe, habitat ranges from hundreds of metres of river to Europe’s largest lakes. As juveniles, those with access to a lake usually migrate to feed and grow prior to reproduction. Prey such as smelt (Osmerus mordax, Osmerus eperlanus) and vendace (Coregonus albula) facilitate large body size (50–85 cm at maturity) and persistence in high-diversity (>20 fish species) environments; small-bodied salmon (10–30 cm at maturity), relying on insects as prey, coexist with few (fewer than five) other fishes. At maturity, weight varies more than 400-fold (17 to 7200 g) among populations, fecundity more than 150-fold (33 to 5600), and longevity almost fivefold (3 to 14 years). Landlocked salmon are managed to support sustainable fishing, achieve conservation and restoration targets, and mitigate threats; successes are evident but multiple challenges persist. Extraordinary variability in life history coupled with extensive breadth of habitat and species co-existence render landlocked Atlantic salmon singularly impressive from a biodiversity perspective.
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| 14. |
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| 15. |
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| 16. |
- Leinonen, J., et al.
(author)
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Reactivity of anti-PSA monoclonal antibodies with recombinant human kallikrein-2
- 1999
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In: Tumor Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 20:SUPPL. 1, s. 35-37
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Journal article (peer-reviewed)abstract
- Seventy-nine monoclonal antibodies submitted to the ISOBM TD-3 PSA Workshop were tested for their reactivity with recombinant human kallikrein-2 (rhK2). A sandwich immunofluorometric assay using polyclonal antiprostate- specific antigen (PSA) antiserum-coated plates was used to capture rhK2 and subsequently the test antibody. The response of each test antibody was compared with 3 reference antibodies (H50, H117 and 5E4) known to react with hK2. Nine antibodies from the workshop panel failed to react with purified PSA and rhK2 in this assay and were subsequently excluded. From the remaining panel of antibodies, 11/70 showed strong reactivity with rhK2, 9/70 showed weak reactivity with rhK2, while 50/70 antibodies did not react with rhK2 in this assay format. All antibodies binding to rhK2 recognized both free and complexed PSA.
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| 17. |
- Lilja, Hans, et al.
(author)
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Significance and metabolism of complexed and noncomplexed prostate specific antigen forms, and human glandular kallikrein 2 in clinically localized prostate cancer before and after radical prostatectomy
- 1999
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In: Journal of Urology. - 1527-3792. ; 162:6, s. 2029-2035
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Journal article (peer-reviewed)abstract
- PURPOSE: We studied plasma concentrations and elimination rates of prostate specific antigen (PSA) complexed to alpha1-antichymotrypsin and alpha2-macroglobulin, free PSA, total PSA (free PSA plus PSA alpha1-antichymotrypsin) and human glandular kallikrein 2 before, during and after radical retropubic prostatectomy for clinically localized prostate cancer. MATERIALS AND METHODS: Plasma was collected and frozen within 10 minutes after sampling from 18 patients undergoing radical retropubic prostatectomy for prostate cancer. One sample was drawn preoperatively. Subsequent sampling intervals were 5 to 20 minutes perioperatively, 2 to 4 hours during the first 12 postoperative hours and 24 to 48 hours until postoperative day 14. Free PSA, PSA alpha1-antichymotrypsin, total PSA, PSA alpha2-macroglobulin and human glandular kallikrein 2 were measured with time resolved immunofluorometric assays. RESULTS: Preoperatively PSA alpha2-macroglobulin was undetectable (less than 2 ng./ml.) in 17 of 18 patients. Human glandular kallikrein 2, free PSA and total PSA but not PSA alpha1-antichymotrypsin were significantly higher in patients with extraprostatic cancer (pT3a-pT4a, pN1) compared to those with organ confined cancer (pT2a/b). Surgical manipulation of the prostate caused no detectable elevation of human glandular kallikrein 2, PSA alpha1-antichymotrypsin or PSA alpha2-macroglobulin. In contrast, a mean 9.6-fold increase (range 3.4 to 22) in free PSA was noted 5 minutes after prostatectomy. Free PSA was eliminated from plasma in a biphasic exponential pattern with an early plasma half-life of 55 minutes and a late plasma half-life of 18 hours. PSA alpha1-antichymotrypsin decreased slowly, whereas human glandular kallikrein 2 was detectable only 12 hours after prostatectomy. PSA alpha2-macroglobulin remained at insignificant, nondetectable concentrations during the entire perioperative and postoperative period. CONCLUSIONS: Release of free PSA contributes to the elevation of plasma total PSA after prostatectomy. Free PSA is enzymatically inactive as the release does not result in subsequent elevation of PSA alpha1-antichymotrypsin or PSA alpha2-macroglobulin. Biphasic exponential elimination of free PSA may be explained by rapid extracellular redistribution (early half-life) and glomerular filtration in the kidneys (late half-life). Our data suggest rapid metabolism of human glandular kallikrein 2 but do not support suggestions of the significance in vivo of complex formations with alpha2-macroglobulin as a major means to eliminate PSA from plasma in patients with clinically localized prostate cancer.
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| 18. |
- Lövgren, Janita, et al.
(author)
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Production of recombinant PSA and HK2 and analysis of their immunologic cross-reactivity
- 1995
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In: Biochem Biophys Res Commun. - : Elsevier BV. ; 213:3, s. 888-895
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Journal article (peer-reviewed)abstract
- Measurements of prostate-specific antigen (PSA) in serum are widely used to monitor patients with prostate cancer, but the attenuation of the assay response by PSA complexed to protease inhibitors has been shown to affect the results in certain assay designs. Moreover, the human glandular kallikrein-2 (hK2), a kallikrein-like serine protease that is 80% similar to PSA, might interfere with the specific detection of PSA by immunological cross-reactivity. We have expressed hK2 and PSA in eucaryotic cells using the Semliki Forest Virus expression system and studied the reactivity of 18 monoclonal anti-PSA IgGs. Five of them cross-reacted with identical affinities to recombinant hK2 whereas 13 recognized PSA alone. The antibodies that recognized both PSA and hK2 bind to a region of the protein that is exposed when PSA is complexed to alpha-1-antichymotrypsin.
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| 19. |
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| 20. |
- Nurmikko, P., et al.
(author)
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Production and characterization of novel anti-prostate-specific antigen (PSA) monoclonal antibodies that do not detect internally cleaved Lys145-Lys146 inactive PSA
- 2000
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In: Clinical Chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 46:10, s. 1610-1618
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Journal article (peer-reviewed)abstract
- Background: The nature of free, uncomplexed prostate-specific antigen (s) in the circulation is still unknown. In this study, we developed novel anti-PSA antibodies using PSA produced by a metastasized cancer cell line, LNCaP, as an immunogen. Methods: Hybridoma cell lines were screened with different methods that aimed at finding antibodies specific for the forms of free PSA produced by LNCaP cell line. Obtained antibodies were further studied for their characteristics related to previously characterized monoclonal antibodies. Results: Numerous anti-PSA antibodies were obtained, of which four represented unique epitopes previously unrecognized by us. One free-PSA-specific antibody was bound to PSA on two distinct epitopes, and one antibody was bound to the carboxyl-terminal peptide of PSA. Two antibodies were found to bind to the peptide sequence adjacent to the internal cleavage site Lys145-Lys146. These antibodies failed to recognize internally cleaved PSA at Lys145-Lys146. We could not find anti-proPSA antibodies despite the fact that LNCaP PSA contained more than one-half of the zymogen form of PSA. Conclusions: We report, for the first time, novel anti-PSA antibodies that do not recognize internally cleaved PSA at Lys145-Lys146 and thus are specific for intact, unclipped PSA. (C) 2000 American Association for Clinical Chemistry.
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| 21. |
- Piironen, J, et al.
(author)
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Physical studies of asteroids - XXXII. Rotation periods and UBVRI-colours for selected asteroids
- 1998
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In: ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES. - : E D P SCIENCES. - 0365-0138. ; 128:3, s. 525-540
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Journal article (other academic/artistic)abstract
- We present lightcurves of selected asteroids. Most of the asteroids were included to obtain refined spin periods. Enhanced periods were determined for 11 Parthenope, 306 Unitas and 372 Palma. We confirmed the spin periods of 8 Flora, 13 Egeria, 71 Niobe,
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| 22. |
- Seppa, T, et al.
(author)
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Early familiarity has fitness consequences for Arctic char (Salvelinus alpinus) juveniles
- 2001
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In: CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES. - : NATL RESEARCH COUNCIL CANADA. - 0706-652X. ; 58:7, s. 1380-1385
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Journal article (peer-reviewed)abstract
- Familiarity is an important factor reducing aggressiveness among individuals. Because of the reduced energy and time expenditure due to lowered aggression, individuals would be expected to perform better in groups of familiar conspecifics as compared with
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| 23. |
- Väisänen, V., et al.
(author)
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Characterization and processing of prostate specific antigen (hK3) and human glandular kallikrein (hK2) secreted by LNCaP cells
- 1999
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In: Prostate Cancer and Prostatic Diseases. - : Springer Science and Business Media LLC. - 1365-7852 .- 1476-5608. ; 2, s. 91-97
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Journal article (peer-reviewed)abstract
- Prostate specific antigen (PSA, hK3) in serum is predominantly complexed to α-1-antichymotrypsin (ACT), but a minor fraction remains in a free form despite the very large excess of serine protease inhibitors and α-2- macroglobulin. The fraction of free to total PSA is significantly lower in prostate cancer (CAP) compared to benign prostatic hyperplasia (BPH) which provides improved discrimination of these conditions. The molecular nature of free PSA in the circulation and the reason for its varying concentration in malignant and benign conditions is currently not known. The objective of the present investigation was to study the secretion of PSA and human glandular kallikrein 2 (hK2) by the LNCaP prostate cancer cell line, and to purify and characterize both proteins. LNCaP PSA was thoroughly characterized by immunological characterization, SDS-PAGE, isoelectric focusing, gel filtration, aminoterminal sequencing, reverse-phase chromatography, mass spectrometry and enzymatic activity measurements. LNCAP cells produced approximately equal amounts of zymogen (proPSA) and the one-chain mature form of PSA, whereas there was no evidence for the secretion of any internally cleaved forms. LNCaP cells secreted hK2 into the growth medium at about 3-5% of the amount of PSA. One-chain, mature PSA and hK2 obtained when LNCaP cells were grown in the presence of fetal bovine serum, had no enzymatic activity, but were active when the cells were grown in the absence of serum. Using enzymatically active recombinant hK2, it was possible to activate proPSA secreted by LNCaP cells. ProPSA formed two bands with high isoelectric points (8.2 and 8.4), which disappeared when proPSA was converted to mature PSA with hK2. Cancerous cells produce the zymogen forms of PSA, which by their isoelectric pI points seem to be found in serum of prostate cancer patients, but not BPH patients. Mature, one-chain PSA is inactive in the presence of serum. These findings may be highly relevant for the understanding of the generation of free and complexed PSA in the circulation.
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