Expression and characterization of trypsinogen produced in the human male genital tract

Beyond the biomarker role: prostate-specific antigen (PSA) in the prostate cancer microenvironment

The prostate-specific antigen (PSA) blood test is the accepted biomarker of tumor recurrence. PSA levels in serum correlate with disease progression, though its diagnostic accuracy is questionable. As a result, significant progress has been made in developing modified PSA tests such as PSA velocity, PSA density, 4Kscore, PSA glycoprofiling, Prostate Health Index, and the STHLM3 test. PSA, a serine protease, is secreted from the epithelial cells of the prostate. PSA has been suggested as a molecular target for prostate cancer therapy due to the fact that it is not only active in prostate tissue but also has a pivotal role on prostate cancer signaling pathways including proliferation, invasion, metastasis, angiogenesis, apoptosis, immune response, and tumor microenvironment regulation. Here, we summarize the current standing of PSA in prostate cancer progression as well as its utility in prostate cancer therapeutic approaches with an emphasis on the role of PSA in the tumor microenvironment.

Differential expression of Annexin 2, SPINK1, and Hsp60 predict progression of prostate cancer through bifurcated WHO Gleason score categories in African American men

BACKGROUND

Although studies have observed several markers correlate with progression of prostate cancer (PCa), no specific markers have been identified that accurately predict the progression of this disease, even in African American (AA) men who are generally at higher risk than other ethnic groups. The primary goal of this study was to explore whether three markers could predict the progression of PCa.

METHOD

We investigated protein expression of Annexin 2 (ANX2), serine peptidase inhibitor, kazal type 1(SPINK1)/tumor-associated trypsin inhibitor (TATI), and heat shock protein 60 (Hsp60) in 79 archival human prostate trans-rectal ultrasound (TRUS) biopsy tissues according to a modified World Health Organization (WHO) classification: normal (WHO1a), Gleason Score (GS6 (WHO1b), GS7 subgroups (WHO2 = 3 + 4, WHO3 = 4 + 3), GS8 (WHO4), and GS9-10 (WHO5). AA men aged 41-90 diagnosed from 1990 to 2013 at Howard University were included. Automated staining assessed expression of each biomarker. Spearman correlation assessed the direction and relationship between biomarkers, WHO and modified WHO GS, age, and 5-year survival. A two-tailed t-test and ANOVA evaluated biomarkers expression in relationship to WHO normal and other GS levels, and between WHO GS levels. A logistic and linear regression analysis examined the relationship between biomarker score and WHO GS categories. Kaplan-Meier curves graphed survival.

RESULTS

ANX2 expression decreased monotonically with the progression of PCa while expression of SPINK1/TATI and Hsp60 increased but had a more WHO GS-specific effect; SPINK1/TATI differed between normal and GS 2-6 and HSP60 differed between GS 7 and GS 2-6. WHO GS was found to be significantly and negatively associated with ANX2, and positively with SPINK1/TATI and Hsp60 expression. High SPINK1/TATI expression together with the low ANX2 expression at higher GS exhibited a bi-directional relationship that is associated with PCa progression and survival.

CONCLUSION

Importantly, the data reveal that ANX2, and SPINK1/TAT1 highly associate with WHO GS and with the transition from one stage of PrCa to the next in AA men. Future research is needed in biracial and larger population studies to confirm this dynamic relationship between ANX2 and SPINK1 as independent predictors of PCa progression in all men.

The expression profile and prognostic value of SPINK1 in initially diagnosed bone metastatic prostate cancer

BACKGROUND

SPINK1 has been described to be mutually exclusively expressed in prostate cancer (PCa), but its expression profiles and the probable roles in bone metastatic PCa have not been thoroughly explored.

METHODS

Total of 155 biopsy specimens from initially diagnosed bone metastatic PCa were obtained between 2009.1 and 2012.12. SPINK1 and ERG were detected by using immunohistochemical staining. Factors included age, ECOG score, clinical T stage, Gleason scores (GS), expression of SPINK1 and ERG, baseline PSA, baseline ALP, baseline HGB and PSA normalization, and the association of SPINK1 and ERG with clinical outcomes (CRPC-free survival and overall survival) were analyzed.

RESULTS

Totally, SPINK1 and ERG were mutually independently expressed in the primary tissues of those patients, and their positivity were only 13.5% (21/155) and 10.9% (17/155), respectively. Positive expression of SPINK1 was completely detected in cases with primary Gleason score 4 or 5; on the contrary, the frequency of ERG was much lower. Correlative analysis only found that SPINK1 was linked with PSA response to androgen deprivation therapy (χ(2)  = 11.101, P = 0.001). Survival analysis showed that, ERG was not associated with clinical outcomes in all cases, especially in cases with higher GS (8-10) (n = 90); but SPINK1 was an independent prognostic factor which was associated with adverse CFS of patients with GS 8-10 (CFS: HR = 5.141, 95%CI: 1.108-25.552, P = 0.017).

CONCLUSIONS

It is the first time to simultaneously detect SPINK1 and ERG expression in initially diagnosed bone metastatic PCa. The over-expression of SPINK1 was not only related to poor PSA response, but also significantly associated with the occurrence of CRPC, especially in those with much more aggressive phenotype (GS 8-10). So, SPINK1 could be considered as a useful prognostic predictor for bone metastatic PCa at the time of diagnosis, and further prospective studies are needed to verify the conclusions. Prostate 76:823-833, 2016. © 2016 Wiley Periodicals, Inc.

Biomarker development, from bench to bedside

This review describes studies performed by our group and other laboratories in the field aimed at development of biomarkers not only for cancer but also for other diseases. The markers covered include tumor-associated trypsin inhibitor (TATI), tumor-associated trypsin (TAT), human chorionic gonadotropin (hCG), prostate-specific antigen (PSA) and their various molecular forms, their biology and diagnostic use. The discovery of TATI was the result of a hypothesis-driven project aimed at finding new biomarkers for ovarian cancer among urinary peptides. TATI has since proved to be a useful prognostic marker for several cancers. Recently, it has been named Serine Peptidase Inhibitor Kazal Type 1 (SPINK1) after being rediscovered by several groups as a tumor-associated peptide by gene expression profiling and proteomic techniques and shown to promote tumor development by stimulating the EGF receptor. To explain why a trypsin inhibitor is strongly expressed in some cancers, research focused on the protease that it inhibited led to the finding of tumor-associated trypsin (TAT). Elevated serum concentrations of TAT-2 were found in some cancer types, but fairly high background levels of pancreatic trypsinogen-2 limited the use of TAT-2 for cancer diagnostics. However, trypsinogen-2 and its complex with α1-protease inhibitor proved to be very sensitive and specific markers for pancreatitis. Studies on hCG were initiated by the need to develop more rapid and sensitive pregnancy tests. These studies showed that serum from men and non-pregnant women contains measurable concentrations of hCG derived from the pituitary. Subsequent development of assays for the subunits of hCG showed that the β subunit of hCG (hCGβ) is expressed at low concentrations by most cancers and that it is a strong prognostic marker. These studies led to the formation of a working group for standardization of hCG determinations and the development of new reference reagents for several molecular forms of hCG. The preparation of intact hCG has been adopted as the fifth international standard by WHO. Availability of several well-defined forms of hCG made it possible to characterize the epitopes of nearly 100 monoclonal antibodies. This will facilitate design of immunoassays with pre-defined specificity. Finally, the discovery of different forms of immunoreactive PSA in serum from a prostate cancer patient led to identification of the complex between PSA and α1-antichymotrypsin, and the use of assays for free and total PSA in serum for improved diagnosis of prostate cancer. Epitope mapping of PSA antibodies and establishment of PSA standards has facilitated establishment well-standardized assays for the various forms of PSA.

Generation and application of polyclonal IgY antibodies specific for full-length and nicked prostate-specific antigen

BACKGROUND

The prostate-specific antigen (PSA) is considered an important serum marker for prostate cancer detection, monitoring and staging. The purpose of this study was to generate IgY class antibodies that recognize native PSA and selected epitopes.

METHODOLOGY

Hens immunized with either full-length human PSA or its peptidyl fragment-conjugates produced specific antibodies that were isolated from egg yolks. We developed a monoclonal/IgY sandwich ELISA with a PSA detection limit of 50 pg/ml and a linear range of 0.05-1.0 ng/ml.

CONCLUSION

Because the signal observed for the PSA-specific IgY antibodies by ELISA and the reactivity profile of the epitope-derived IgYs were comparable to those of mouse monoclonal IgG antibodies, avian antibodies may be a cost-effective alternative to mammalian antibodies for prostate cancer diagnostics.

Proteolytic activity of prostate-specific antigen (PSA) towards protein substrates and effect of peptides stimulating PSA activity

Prostate-specific antigen (PSA or kallikrein-related peptidase-3, KLK3) exerts chymotrypsin-like proteolytic activity. The main biological function of PSA is the liquefaction of the clot formed after ejaculation by cleavage of semenogelins I and II in seminal fluid. PSA also cleaves several other substrates, which may explain its putative functions in prostate cancer and its antiangiogenic activity. We compared the proteolytic efficiency of PSA towards several protein and peptide substrates and studied the effect of peptides stimulating the activity of PSA with these substrates. An endothelial cell tube formation model was used to analyze the effect of PSA-degraded protein fragments on angiogenesis. We showed that PSA degrades semenogelins I and II much more efficiently than other previously identified protein substrates, e.g., fibronectin, galectin-3 and IGFBP-3. We identified nidogen-1 as a new substrate for PSA. Peptides B2 and C4 that stimulate the activity of PSA towards small peptide substrates also enhanced the proteolytic activity of PSA towards protein substrates. Nidogen-1, galectin-3 or their fragments produced by PSA did not have any effect on endothelial cell tube formation. Although PSA cleaves several other protein substrates, in addition to semenogelins, the physiological importance of this activity remains speculative. The PSA levels in prostate are very high, but several other highly active proteases, such as hK2 and trypsin, are also expressed in the prostate and may cleave protein substrates that are weakly cleaved by PSA.

PSA forms complexes with α1-antichymotrypsin in prostate

BACKGROUND

PSA is the most useful prostate cancer marker. However, its levels are increased also in some non-malignant conditions. In circulation, the majority of PSA is complexed with protease inhibitors, including α(1) -antichymotrypsin (ACT). The proportion of the PSA-ACT complex is higher in patients with prostate cancer than in controls without cancer. The expression of ACT has been shown to be higher in prostate cancer than in benign prostatic hyperplasia. However, results regarding the extent which PSA forms complexes within the prostate and whether there are differences in complex formation between normal and malignant prostatic tissue are inconsistent and limited.

METHODS

We studied complex formation of PSA secreted by cultured human prostate tissues and in the tissue by in situ proximity ligation assay (PLA). Free, total and active PSA, and the PSA-ACT complex were determined in tissue culture media by immunoassays, immunoblotting, and chromatographic methods.

RESULTS

The majority of PSA in tissue culture medium was free and enzymatically active. However, a significant proportion (1.6 ± 0.5%) of immunoreactive PSA was found to be complexed with ACT. Complex formation was confirmed by in situ PLA, which showed more intense staining of PSA-ACT in cancers with Gleason grade 3 than in adjacent benign tissues from the same patients.

CONCLUSIONS

These results show that PSA forms complexes already within the prostate and that PSA-ACT levels are increased in moderately differentiated prostate cancer tissue. This may explain, at least partially, why the ratio of serum PSA-ACT to total PSA is increased in prostate cancer.

Treatment of human sperm with serine protease during density gradient centrifugation

PURPOSE

Seminal pathogens can bind specifically or non-specifically to spermatozoa, rendering semen decontamination procedures ineffective, whereby vertical or horizontal transmission of the infection could occur. Serine proteases have been demonstrated to effectively inactivate viruses and to break pathogen-sperm bonds. However, the addition of a protease to density gradient layers during semen processing could negatively impact on sperm parameters. This study investigated the effect of the addition of a recombinant, human-sequence protease (rhProtease) on sperm parameters during density gradient centrifugation.

METHODS

(i) Pooled semen samples (n = 9) were split and processed by density gradient centrifugation, with the top density layers supplemented, or non-supplemented with rhProtease at three different concentrations (diluted 2, 10 and 20 times). Sperm parameters were then analysed by flow cytometry and computer-assisted semen analyses. (ii) Semen samples (n = 5) were split and similarly processed using PureSperm® Pro, with rhProtease in the 40 % density gradient layer, or standard PureSperm® not supplemented with rhProtease (Nidacon, International) respectively. The Hemizona assay was then utilized to compare sperm-zona binding post processing.

RESULTS

Evaluation of sperm parameters indicated that rhProtease did not, at any of the tested concentrations, have an impact on (i) mitochondrial membrane potential, vitality, motility, or (ii) zona binding potential.

CONCLUSION

We report that the addition of rhProtease to density gradients is a non-detrimental approach that could improve the effectiveness of semen processing for the elimination of seminal pathogens, and benefit assisted reproduction outcome.

Sperm proteins in teleostean and chondrostean (sturgeon) fishes

Sperm proteins in the seminal plasma and spermatozoa of teleostean and chondrostean have evolved adaptations due to the changes in the reproductive environment. Analysis of the composition and functions of these proteins provides new insights into sperm motility and fertilising abilities, thereby creating possibilities for improving artificial reproduction and germplasm resource conservation technologies (e.g. cryopreservation). Seminal plasma proteins are involved in the protection of spermatozoa during storage in the reproductive system, whereas all spermatozoa proteins contribute to the swimming and fertilising abilities of sperm. Compared to mammalian species, little data are available on fish sperm proteins and their functions. We review here the current state of the art in this field and focus on relevant subjects that require attention. Future research should concentrate on protein functions and their mode of action in fish species, especially on the role of spermatozoa surface proteins during fertilisation and on a description of sturgeon sperm proteins.

Antiangiogenic properties of prostate-specific antigen (PSA)

The prostate produces high levels of prostate-specific antigen (PSA, also known as kallikrein-related peptidase 3, KLK3), which is a potential target for tumor imaging and treatment. Although serum PSA levels are elevated in prostate cancer, PSA expression is lower in malignant than in normal prostatic epithelium and it is further reduced in poorly differentiated tumors. PSA has been shown to inhibit angiogenesis both in in vitro and in vivo models. In this review we focus on our recent studies concerning the mechanism of the antiangiogenic function of PSA. We have recently shown that the antiangiogenic activity of PSA is related to its enzymatic activity. Inactive PSA isoforms do not have antiangiogenic activity as studied by a human umbelical vein endothelial cell (HUVEC) tube formation model. Furthermore, inhibition of PSA, either by a monoclonal antibody or small molecule inhibitors abolishes the effect of PSA, while a peptide that stimulates the activity of PSA enhances the antiangiogenic effect. We have analyzed changes in gene expression associated with the PSA induced reduction of tube formation in the HUVEC model. Several small changes were observed and they were found to be opposite to those associated with tube formation. Taken together, these studies suggest that PSA exerts antiantiogenic activity related to its enzymatic activity. Thus it might be associated with the slow growth of prostate cancer.

Technical note: effect of density gradient centrifugation with trypsin on the in vivo fertilising capability of bovine spermatozoa

The present study investigated the effect of a novel density gradient centrifugation (DGC) treatment using recombinant trypsin on the in vivo fertilising capability of bovine spermatozoa compared with a standard method. In Trial 1, semen collected from Boran and Ankole (Bos indicus) bulls was treated either with a silane-coated silica particle colloid formulated for humans with a recombinant trypsin or processed using a standard method (dilution in an egg yolk-based diluent). Semen processed by the two methods was used to artificially inseminate (AI) superovulated cattle. Day 7 embryos were flushed and assessed for fertilisation rates and embryo quality. Trial 2 used a trypsinised silane-coated silica particle colloid formulated specifically for bovine semen. Trial 1 resulted in significantly higher fertilisation rates using the trypsinised human DGC treatment than cows inseminated using the standard method (75.2% v. 67%, respectively; P < 0.01), but the numbers of transferable-quality Day 7 embryos did not differ between the two groups (P > 0.05). Results for Trial 2 indicated that cows inseminated with the trypsinised bovine DGC treatment had significantly increased fertilisation rates compared with the standard method (88.4% v. 63.1%, respectively; P < 0.01) and had significantly higher numbers of transferable-quality embryos (70.3% v. 51.8%, respectively; P < 0.01). In summary, bovine sperm treatment before AI by DGC and recombinant trypsin increases fertilisation rates and can result in more transferable-quality embryos compared with standard methods.

Development of peptides specifically modulating the activity of KLK2 and KLK3

The prostate produces several proteases, the most abundant ones being kallikrein-related peptidase 3 (KLK3, PSA) and KLK2 (hK2), which are potential targets for tumor imaging and treatment. KLK3 expression is lower in malignant than in normal prostatic epithelium and it is further reduced in poorly differentiated tumors, in which the expression of KLK2 is increased. KLK3 has been shown to inhibit angiogenesis, whereas KLK2 may mediate tumor growth and invasion by participating in proteolytic cascades. Thus, it may be possible to control prostate cancer growth by modulating the proteolytic activity of KLK3 and KLK2. We have developed peptides that very specifically stimulate the activity of KLK3 or inhibit that of KLK2. Using these peptides we have established peptide-based methods for the determination of enzymatically active KLK3. The first-generation peptides are unstable in vivo and are rapidly cleared from the circulation. Currently we are modifying the peptides to make them suitable for in vivo applications. We have been able to considerably improve the stability of KLK2-binding peptides by cyclization. In this review we summarize the possible roles of KLK3 and KLK2 in prostate cancer and then concentrate on the development of peptides that modulate the activity of these proteases.

Proteinase-activated receptors in the lower urinary tract

Proteinase-activated receptors (PARs) are G-protein-coupled receptors that convert specific extracellular proteolytic activity into intracellular signals, and have been suggested to play diverse roles in the body. In this review, evidence for the roles of PARs in bladder contractility and inflammation are presented. The role of PARs in prostate cancer is also reviewed. The existing literature in this area can be difficult to interpret due to the many nonspecific actions of the pharmacological tools employed. Although there are reports that PAR activators can cause contraction of bladder smooth muscle, further pharmacological and molecular studies are required to define roles for these receptors in bladder contractility. While structural studies suggest that roles for PARs in bladder inflammation are likely, few functional investigations have been performed. The significance of the expression of PARs on sensory nerves innervating the bladder and changes in receptor expression in inflammatory disease models are fascinating areas for future research. Finally, it seems probable that PARs, particularly PAR1, may play important roles in the growth and metastasis of prostate cancers.

Increased expression of tumor-associated trypsin inhibitor, TATI, in prostate cancer and in androgen-independent 22Rv1 cells

OBJECTIVES

Tumor-associated-trypsin inhibitor (TATI) is frequently coexpressed with trypsinogen in tumors. Recently, we found expression of trypsinogens in prostate cancer. We have now studied whether TATI is also expressed in prostate cancer and if TATI expression is associated with Gleason grade, proliferation, and neuroendocrine differentiation.

METHODS

Expression of TATI and prostate-specific antigen (PSA) was studied by immunohistochemistry and in situ hybridization, and that of chromogranin A (CgA) and Ki-67 by immunohistochemistry. Immunofluorometric assays were used to quantify TATI and PSA in serum from prostate cancer patients and in medium of 22Rv1 prostate cancer cells.

RESULTS

TATI expression was weak in benign prostatic epithelium and moderate to strong in prostate cancer and high-grade prostatic intraepithelial neoplasia. There was no correlation between TATI and Ki-67 immunostaining in a tissue microarray of 115 prostate cancer cores, but strong expression of TATI was associated with higher Gleason grade (p=0.002) and CgA immunostaining intensity (p=0.012). Serum TATI was elevated in 44% (29 of 66) of patients with prostate cancer, and the levels correlated with serum PSA (p<0.0001, r=0.306). DU145, PC-3, LNCaP, and 22Rv1 cells contained TATI mRNA as determined by RT-PCR, but only 22Rv1 cells produced detectable TATI protein. The synthetic androgen R1881 decreased secretion of TATI from 22Rv1 cells.

CONCLUSIONS

We demonstrate for the first time that TATI is expressed in the benign and malignant prostate. Increased TATI protein expression is found in high-grade tumors and in 22Rv1 cells in which it is regulated by androgens.

Mucin gene expression in human male urogenital tract epithelia

BACKGROUND

Mucins are large, hydrophilic glycoproteins that protect wet-surfaced epithelia from pathogen invasion as well as provide lubrication. At least 17 mucin genes have been cloned to date. This study sought to determine the mucin gene expression profile of the human male urogenital tract epithelia, to determine if mucins are present in seminal fluid and to assess the effect of androgens on mucin expression.

METHODS AND RESULTS

Testis, epididymis, vas deferens, seminal vesicle, prostate, bladder, urethra and foreskin were assessed for mucin expression by RT-PCR (for 14 mucin genes) and immunohistochemistry (nine antibodies for five mucins). Epithelia of the vas deferens, prostate and urethra expressed the greatest number of mucins, each with mRNA for between 5 and 8 mucins. Except for MUC20 in epididymis, mRNA for MUC1 and MUC20, both membrane-associated mucins, was detected in all tissues analysed. By comparison, MUC6 was more restricted in expression, being primarily detected in seminal vesicle. MUC1, MUC5B and MUC6 were detected in seminal fluid samples by immunoblot analysis. Androgens had no effect on mucin expression in cultured human prostatic epithelial cells.

CONCLUSIONS

Each region of urogenital tract epithelium expressed a unique mucin gene repertoire. Secretory mucins are present in seminal fluid, and androgens do not appear to regulate mucin gene expression in prostatic epithelial cells in culture.

Biochemistry and clinical role of trypsinogens and pancreatic secretory trypsin inhibitor

Trypsinogens and PSTI/TATI/SPINK1 are expressed, usually together, at high levels by the pancreas but also by many other normal and malignant tissues. The present review describes studies on the expression and putative functions of trypsinogens and PSTI/TATI/SPINK1 in the human body. The clinical aspects are discussed, including the correlations between expression of trypsinogens and PSTI/TATI/SPINK1 in tissues, serum, and urine of patients with pancreatitis or cancer and clinicopathological characteristics, i.e., the roles of trypsinogens and PSTI/TATI/SPINK1 in spontaneous and hereditary pancreatitis, tumor progression, and prognosis.

Use of a novel washing method combining multiple density gradients and trypsin for removing human immunodeficiency virus-1 and hepatitis C virus from semen

OBJECTIVE

To determine the effectiveness of a novel treatment designed to remove human immunodeficiency virus (HIV) -1 and hepatitis C virus (HCV) from spiked semen and to evaluate sperm motility and viability after treatment.

DESIGN

A prospective clinical laboratory-based study.

SETTING

The human studies were conducted in academic and national research environments. The bovine study was conducted in an accredited research facility.

PATIENT(S)

Healthy volunteers provided the semen samples used in the human studies; abattoir-derived material was used for the bovine embryo production study.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

Cytopathic, reverse transcriptase-polymerase chain reaction, and branched DNA assays were used to test the efficacy of the procedure for inactivating or removing viruses from spiked semen; standard semen evaluation criteria were used to assess the effects of the procedures on sperm motility and viability.

RESULT(S)

Trypsin exposure significantly reduced the infectivity of HIV-1. The triple density gradient treatment, with or without trypsin, had no detrimental affect on fresh or cryopreserved/thawed sperm 2-48 hours after treatment. The treatment of semen spiked with HIV-1 or HCV indicated that the procedure was effective for reducing viral copies to undetectable levels or below levels of clinical relevance.

CONCLUSION(S)

The procedure was effective for significantly inactivating or reducing HIV-1 and HCV in spiked semen without adversely affecting sperm quality.

Prognostic value of serum markers for prostate cancer

The incidence of prostate cancer has increased dramatically during the last 10-15 years and it is now the commonest cancer in males in developed countries. The increase is mainly caused by the increasing use of opportunistic screening or case-finding based on the use of prostate-specific antigen (PSA) testing in serum. With this approach, prostate cancer is detected 5-10 years before giving rise to symptoms and on average 17 years before causing the death of the patient. While this has led to detection of prostate cancer at a potentially curable stage, it has also led to substantial overdiagnosis, i.e. detection of cancers that would not surface clinically in the absence of screening. A major challenge is thus to identify the cases that need to be treated while avoiding diagnosing patients who will not benefit from being diagnosed and who will only suffer from the stigma of being a cancer patient. It would be useful to have prognostic markers that could predict which patients need to be diagnosed and which do not. Ideally, it should be possible to measure these markers using non-invasive techniques, i.e. by means of serum or urine tests. As it is very useful for both early diagnosis and monitoring of prostate cancer, PSA is considered the most valuable marker available for any tumor. Although the prognostic value of PSA is limited, measurement of the proportion of free PSA has improved the identification of patients with aggressive disease. Furthermore, the rate of increase in serum PSA reflects tumor growth rate and prognosis but, due to substantial physiological variation in serum PSA, reliable estimation of the rate of PSA increase requires follow-up for at least 2 years. Algorithms based on the combined use of free and total PSA and prostate volume in logistic regression and neural networks can improve the diagnostic accuracy for prostate cancer, and assays for minor subfractions of PSA and other new markers may provide additional prognostic information. Markers of neuroendocrine differentiation are useful for the monitoring of androgen-independent disease and various bone markers are useful in patients with metastatic disease.

Distinct defensin profiles in Neisseria gonorrhoeae and Chlamydia trachomatis urethritis reveal novel epithelial cell-neutrophil interactions

Defensins are key participants in mucosal innate defense. The varied antimicrobial activity and differential distribution of defensins at mucosal sites indicate that peptide repertoires are tailored to site-specific innate defense requirements. Nonetheless, few studies have investigated changes in peptide profiles and function after in vivo pathogen challenge. Here, we determined defensin profiles in urethral secretions of healthy men and men with Chlamydia trachomatis- and Neisseria gonorrhoeae-mediated urethritis by immunoblotting for the epithelial defensins HBD1, HBD2, and HD5 and the neutrophil defensins HNP1 to -3 (HNP1-3). HBD1 was not detectable in secretions, and HBD2 was only induced in a small proportion of the urethritis patients; however, HD5 and HNP1-3 were increased in C. trachomatis infection and significantly elevated in N. gonorrhoeae infection. When HNP1-3 levels were low, HD5 appeared mostly as the propeptide; however, when HNP1-3 levels were >10 microg/ml, HD5 was proteolytically processed, suggesting neutrophil proteases might contribute to HD5 processing. HD5 and HNP1-3 were bactericidal against C. trachomatis and N. gonorrhoeae, but HD5 activity was dependent upon N-terminal processing of the peptide. In vitro proteolysis of proHD5 by neutrophil proteases and analysis of urethral secretions by surface-enhanced laser desorption ionization substantiated that neutrophils contribute the key convertases for proHD5 in the urethra during these infections. This contrasts with the small intestine, where Paneth cells secrete both proHD5 and its processing enzyme, trypsin. In conclusion, we describe a unique defensin expression repertoire in response to inflammatory sexually transmitted infections and a novel host defense mechanism wherein epithelial cells collaborate with neutrophils to establish an antimicrobial barrier during infection.

Expression of tumor-associated trypsinogens (TAT-1 and TAT-2) in prostate cancer

BACKGROUND

Trypsinogens are pancreatic serine proteinases and expressed in several cancers as tumor-associated trypsinogens (TAT). Trypsin mediates activation of pro-uPA and pro-MMPs, thus promoting angiogenesis and tumor invasion. Recently, we described expression of TAT in the human male genital tract and now we studied TAT in relation to PSA in PCa.

METHODS

TAT expression was studied by immunohistochemistry, in situ hybridization, RT-PCR, DNA-sequencing and IFMA. LNCaP cells were used to study secretion of TAT and PSA after androgen stimulation.

RESULTS

Immunoreactive TAT was localized in all prostatic tumors (n = 109), lymph node (n = 16), and bone metastases (n = 17). Immunostaining intensity increased with higher Gleason's grade, whereas PSA immunostaining decreased significantly. PSA and TAT were not identically distributed in benign and malignant cells. Androgen stimulation of LNCaP cells decreased secretion of TAT and increased that of PSA. TAT mRNA was demonstrated in tissue sections and identified as TAT-1 and -2 by RT-PCR and DNA-sequencing.

CONCLUSIONS

Expression of TAT is better preserved than PSA in high-grade PCa. Expression of TAT and PSA is regulated by different mechanisms as demonstrated in tissue sections and in vitro. Locally produced TAT may act in a paracrine mode to promote angiogenesis and tumor invasion in PCa by both activating and degrading of other proteinases. Further studies on the role of TAT in invasive PCa and on the mechanisms involved in the regulation of TAT expression are warranted.

Relative concentrations of hK2/PSA mRNA in benign and malignant prostatic tissue

BACKGROUND

Prostate-specific antigen (PSA/KLK3) and human kallikrein 2 (hK2/KLK2) belong to the human kallikrein gene family. These two highly homologous genes are specifically expressed in the prostate under androgen control. Expression of these is regulated by similar mechanisms but changes in their relative expression have been observed in prostate cancer.

METHODS

We determined the relative levels of PSA and hK2 mRNA in benign and malignant prostate tissue using a quantitative reverse transcription-polymerase chain reaction (RT-PCR) method. The mRNA of PSA and hK2 are reverse transcribed and amplified in one reaction with the same primers.

RESULTS

The variation in the ratio of hK2/PSA mRNA was remarkably small, the difference between the highest and lowest values being three-fold. The ratio was significantly higher in WHO grade 2 compared to normal or benign prostatic hyperplasia tissue (P = 0.032 and P = 0.035, respectively) and in grade 3 compared to normal or benign prostatic hyperplasia tissue (P = 0.006 in both).

CONCLUSIONS

The new quantitative RT-PCR technique facilitates very accurate quantitation of the relative mRNA levels of homologous genes. Using this method we have shown that the ratio of hK2/PSA mRNA is higher in cancerous than in benign prostatic tissue.

Expression and Signaling Activity of Wnt-5a/Discoidin Domain Receptor-1 and Syk Plays Distinct but Decisive Roles in Breast Cancer Patient Survival

Purpose: The loss of Wnt-5a, a G-protein-coupled receptor ligand, or Syk, an intracellular kinase, has in separate studies been associated with poor prognosis of breast cancer patients. Both proteins are involved in cell adhesion, a key event in epithelial cancer metastasis. Here, we have investigated whether Syk is part of the Wnt-5a/discoidin domain receptor-1 (DDR1) signaling pathway and if a signaling interaction of these proteins is important for breast cancer–specific survival.

Experimental Design: The signaling interactions between Wnt-5a/DDR1 and Syk were addressed in mammary cell lines. Their mRNA and protein levels and the respective clinical correlates were investigated in 94 cases of primary breast cancer.

Results: The expression of Wnt-5a and Syk correlated in four of five tumor cell lines. However, despite a constitutive association between Syk and the Wnt-5a-dependent adhesion receptor DDR1, we found no evidence of a Wnt-5a/DDR1-mediated activation of Syk. Instead, β1 integrins initiate the adhesion-induced activation of Syk. In tumors from breast cancer patients, the protein expression of Wnt-5a and Syk were differently regulated at the translational and transcriptional level, respectively. Analysis of breast cancer–specific survival revealed that the presence of Wnt-5a and Syk in primary tumors has good predictive value for a favorable outcome. Intriguingly, a simultaneous loss of both proteins did not reduce survival more than loss of either.

Conclusions: Despite the difference in regulation of Wnt-5a and Syk protein expression and their lack of signaling interaction, our clinical data indicate that a favorable prognosis in breast cancer requires the expression and signaling activity of both.

Expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor in ovarian cancer: prognostic study on tissue and serum

PURPOSE

The purpose is to study the prognostic significance of tissue expression of trypsinogen-1, trypsinogen-2, and tumor-associated trypsin inhibitor (TATI) and serum concentration of trypsinogen-2, trypsin-2-API (complex of trypsin-2 with alpha-1-proteinase inhibitor), and TATI in epithelial ovarian cancer.

EXPERIMENTAL DESIGN

Expression of trypsinogen-1, trypsinogen-2, and TATI was determined by immunohistochemistry with monoclonal antibodies in tissue sections of tumors from 119 patients with untreated primary epithelial ovarian cancer. Preoperative serum concentrations of trypsinogen-2, trypsin-2-API and TATI were analyzed using specific immunoassays.

RESULTS

Fifty-four percent of the tumors expressed trypsinogen-1, 45% expressed trypsinogen-2, and 30% expressed TATI. In patients with stage III and IV disease, TATI tissue expression (P = 0.002) and elevated TATI concentration in serum (P = 0.048) were associated with adverse cancer-specific and progression-free survival in univariate analysis. In multivariate analysis, TATI tissue expression (P = 0.005), tumor grade (P = 0.0001), histological type (P = 0.02), and stage (P = 0.0005) were independent prognostic factors for adverse cancer-specific survival and TATI tissue expression (P = 0.006) and grade (P = 0.0003) for progression-free survival. In multivariate analysis of all patients and those with advanced disease, serum trypsin-2-API concentration was an adverse prognostic factor for cancer-specific and progression-free survival, and it was independent of stage and histological type of the tumor (P <or= 0.01).

CONCLUSIONS

Tissue expression of TATI and an elevated preoperative serum concentration of trypsin-2-API are strong independent prognostic factors in advanced epithelial ovarian cancer. These results suggest that trypsin expression plays a role in the progression of ovarian cancer. TATI and trypsin-2-API are of potential use as an aid for stratification of randomized studies and for selecting treatment strategies.

Expression of protein C inhibitor (PCI) in benign and malignant prostatic tissues

BACKGROUND

Protein C inhibitor (PCI) occurs at high concentration in seminal plasma, and inhibits human glandular kallikrein-2 and, less readily, prostate-specific antigen. Previous studies have localized PCI in the male genital tract. Here we have performed a detailed investigation of PCI expression in the prostatic tissues, metastases, and cell lines.

METHODS

Immunohistochemistry, in situ hybridization, and Western blotting were used to study prostatic tissues, metastases, and PC-3, DU-145, and LNCaP cells.

RESULTS

PCI was immunolocalized in tissue microarray spots with BPH epithelium (detection rate 100%), PIN lesions (100%), tumors (96%), metastases (88%), and in all cell lines. ISH and WB supported the findings.

CONCLUSIONS

PCI is widely expressed in benign prostatic epithelium, and may act as a local regulator of enzymatic activity in seminal fluid, of importance for normal sperm function. Lack of PCI expression in a subpopulation of high-grade tumor cells in combination with maintained protease expression may facilitate invasive growth patterns.

Anti-thrombin is expressed in the benign prostatic epithelium and in prostate cancer and is capable of forming complexes with prostate-specific antigen and human glandular kallikrein 2

Anti-thrombin, a member of the serpin family and an inhibitor of thrombin and blood coagulation factor Xa, was recently shown to inhibit angiogenesis and tumor growth. In the present study, we examined the expression of anti-thrombin in benign and malignant prostate gland. Using immunohistochemistry, anti-thrombin was found in prostate epithelium and stroma cells. Tissue microarrays of tumors (n = 112) and three different prostate cancer cell lines (PC-3, LNCaP, and DU-145) were all positive for anti-thrombin. Abundant expression in a population of prostatic tumor cells was further evidenced by in situ hybridization experiments. The immunostaining for anti-thrombin was confined to the cytoplasm, was most intense in Gleason grade 3 tumors, and in part overlapped with that of prostate-specific antigen. Western blotting of benign and malignant tissue homogenates revealed a predominant 58-kd anti-thrombin immunoreactive component. In vitro, anti-thrombin formed complexes more readily with human kallikrein 2, particularly in the presence of heparin, and less efficiently with prostate-specific antigen. Both complexes could be recognized by polyclonal and monoclonal IgGs against anti-thrombin. We conclude that anti-thrombin is widely expressed in prostate cancer but is gradually lost in tumors of high Gleason grade. Anti-thrombin may act as a local anti-angiogenic factor, the effect of which is partially lost in poorly differentiated prostatic tumors.

Paneth cell trypsin is the processing enzyme for human defensin-5

The antimicrobial peptide human alpha-defensin 5 (HD5) is expressed in Paneth cells, secretory epithelial cells in the small intestine. Unlike other characterized defensins, HD5 is stored in secretory vesicles as a propeptide. The storage quantities of HD5 are approximately 90 450 microg per cm2 of mucosal surface area, which is sufficient to generate microbicidal concentrations in the intestinal lumen. HD5 peptides isolated from the intestinal lumen are proteolytically processed forms--HD5(56-94) and HD5(63-94)--that are cleaved at the Arg55-Ala56 and Arg62-Thr63 sites, respectively. We show here that a specific pattern of trypsin isozymes is expressed in Paneth cells, that trypsin colocalizes with HD5 and that this protease can efficiently cleave HD5 propeptide to forms identical to those isolated in vivo. By acting as a prodefensin convertase in human Paneth cells, trypsin is involved in the regulation of innate immunity in the small intestine.

Comparison, characterization, and identification of proteases and protease inhibitors in epididymal fluids of domestic mammals. Matrix metalloproteinases are major fluid gelatinases

The testicular and epididymal fluids of ram, boar, and stallion were analyzed by means of one-dimensional and two-dimensional gelatin gel zymography. Five main gelatinolytic bands were revealed in the ram and at least seven were observed in the boar and stallion. These proteolytic bands showed regionalized distribution throughout the organs. The two main proteolytic activities at around 54-66 kDa retrieved in all three species were inhibited by EDTA and phenanthroline, indicating that they were metallo-dependent enzymes. The activity of some of the low-molecular-weight gelatinases was also decreased by EDTA, whereas others were inhibited by serine protease inhibitors. One of the main proteases at 60-62 kDa from the caput fluid of the stallion and the ram was N-terminal sequenced; in both cases, high sequence homology was found with the N-terminal of the matrix-metalloproteinase-2 pro-form (pro-MMP-2). Antibodies against MMP-2, MMP-3, and MMP-9 gelatinases confirmed the regional distribution in the fluids of pre -, pro-, active, or degraded forms of these metalloproteases in all three species. We also observed the presence of acrosin in epididymal fluids, which was probably released by dead spermatozoa, but this enzyme did not explain all the serine protease activity. Moreover, the majority of this enzyme is bound to the protease inhibitor alpha(2)-macroglobulin, which is present in the fluids of all three species. TIMP-2, a potent inhibitor of MMPs, was present in the fluid of the caput regions in the ram and boar, and in the caput and caudal fluids of the stallion. This study demonstrated that similar types of proteases and inhibitors are regionally distributed in the epididymal fluids of three domestic species, suggesting an identical role in the sperm maturation process, the plasticity of this organ, or both.

Prostate-specific antigen and other prostate-derived proteases cleave IGFBP-3, but prostate cancer is not associated with proteolytically cleaved circulating IGFBP-3

BACKGROUND

Proteolysis of insulin-like growth factor-binding proteins (IGFBPs) may increase IGF-mediated growth stimulation and development of cancer in the organs producing large amounts of proteases, such as the prostate.

METHODS

We studied proteolysis of IGFBP-3 by three prostate-derived proteases, namely prostate specific antigen (PSA), human kallikrein 2 (hK2), and trypsin, and also by native seminal plasma. Cleavage of 125I-IGFBP-3 was studied by SDS-PAGE and autoradiography. We also used two different sandwich-type IGFBP-3 immunoassays, called "intact" and "total" IGFBP-3 assays. These assays differ in their capacity to recognize proteolytically degraded IGFBP-3.

RESULTS

HK2, PSA, and trypsin all cleaved IGFBP-3 at the concentrations normally present in seminal plasma. The IGFBP-3 cleavage by seminal plasma was inhibited by ZnCl2, which strongly inhibits hK2 and PSA, but not by a specific trypsin inhibitor. The IGFBP-3 fragments resulting from proteolytic cleavage by PSA, hK2, or trypsin were undetectable in the "intact IGFBP-3 assay," whereas the "total IGFBP-3 assay" also detected the proteolytic fragments. No increased fragmentation of IGFBP-3 was found in serum of 659 men with elevated PSA concentrations, of whom 178 had a proven prostate cancer. Furthermore, the IGFBP-3 levels were not associated with the PSA concentrations.

CONCLUSIONS

These results show that, while seminal plasma and prostate-derived proteases can cleave IGFBP-3, in patients with prostate cancer the circulating IGFBP-3 is not significantly proteolyzed by either PSA, hK2, or trypsin.