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Nijmegen, Netherlands

Pfeiffer M.J.,Radboud University Nijmegen | Smit F.P.,NovioGendix | Sedelaar J.P.M.,Radboud University Nijmegen | Schalken J.A.,Radboud University Nijmegen
Molecular Medicine

Considerable levels of testosterone and dihydrotestosterone (DHT) are found in prostate cancer (PCa) tissue after androgen deprivation therapy. Treatment of surviving cancer-initiating cells and the ability to metabolize steroids from precursors may be the keystones for the appearance of recurrent tumors. To study this hypothesis, we assessed the expression of several steroidogenic enzymes and stem cell markers in clinical PCa samples and cell cultures during androgen depletion. Gene expression profiles were determined by microarray or qRT-PCR. In addition, we measured cell viability and analyzed stem cell marker expression in DuCaP cells by immunocytochemistry. Seventy patient samples from different stages of PCa, and the PCa cell line DuCaP were included in this study. The androgen receptor (AR) and enzymes (AKR1C3, HSD17B2, HSD17B3, UGT2B15 and UGT2B17) that are involved in the metabolism of adrenal steroids were upregulated in castration resistant prostate cancer (CRPC). In vitro, some DuCaP cells survived androgen depletion, and eventually gave rise to a culture adapted to these conditions. During and after this transition, most of the steroidogenic enzymes were upregulated. These cells also are enriched with stem/progenitor cell markers cytokeratin 5 (CK5) and ATP-binding cassette sub-family G member 2 (ABCG2). Similarly, putative stem/progenitor cell markers CK5, c-Kit, nestin, CD44, c-met, ALDH1A1, α2-integrin, CD133, ABCG2, CXCR4 and POU5F1 were upregulated in clinical CRPC. The upregulation of steroidogenic enzymes and stem cell markers in recurrent tumors suggests that cancer initiating cells can expand by adaptation to their T/DHT deprived environment. Therapies targeting the metabolism of adrenal steroids by the tumor may prove effective in preventing tumor regrowth. © 2011 The Feinstein Institute for Medical Research. Source

Hendriks R.J.,Radboud University Nijmegen | Dijkstra S.,Radboud University Nijmegen | Jannink S.A.,NovioGendix | Steffens M.G.,Isala Hospital | And 3 more authors.
Clinical Chemistry and Laboratory Medicine

Background: PCA3 and ERG are mRNA-based prostate cancer (PCa) specific biomarkers that can be detected in urine. However, urine is a complex substrate that can be separated in several fractions. In this study we compared the levels of PCa-specific biomarkers (PCA3 and ERG) and KLK3 as prostate-specific reference gene in three urine substrates-whole urine, urinary sediment (cell pellet) and exosomes-and evaluated the influence of performing a digital rectal examination (DRE) prior to urine sampling. Methods: First-voided urine samples were prospectively obtained before and after DRE from 29 men undergoing prostate biopsies. The urine was separated in whole urine, cell pellet and exosomes and the biomarker levels were measured with RT-qPCR. Results: PCa was identified in 52% (15/29) of men. In several samples the mRNA levels were below the analytical limit of detection (BDL). The biomarker levels were highest in whole urine and significantly higher after DRE in all substrates. In PCa patients higher levels of PCA3 and ERG were found in all urine substrates after DRE compared to non-PCa patients. Conclusions: This is the first study in which urinary PCa-specific biomarker levels were compared directly in three separate urine fractions. These results suggest that whole urine could be the urine substrate of choice for PCa-diagnostics based on analytical sensitivity, which is reflected directly in the high informative rate. Moreover, the significant positive effect of performing a DRE prior to urine sampling is confirmed. These findings could be of influence in the development of PCa-diagnostic urine tests. © 2016 by De Gruyter 2016. Source

Salagierski M.,Radboud University Nijmegen | Salagierski M.,Medical University of Lodz | Verhaegh G.W.,Radboud University Nijmegen | Verhaegh G.W.,Nijmegen Center for Molecular Life science | And 5 more authors.

BACKGROUND. PCA3 is one of the most prostate cancer (PrCa)-specific markers described so far. Recently, a new genomic structure of PCA3 as well as new flanking and overlapping gene transcripts has been identified. Furthermore, a co-regulation of PCA3 and its overlapping gene PRUNE2(BMCC1) has been suggested. Our aim was to assess the diagnostic performance of a new PCA3 isoform (PCA3-TS4) and to study the interactions between PCA3 and BMCC1in PrCa. METHODS. Weused SYBR Green quantitative (q)PCR with specific primers to compare PCA3 and BMCC1 expression of normal versus tumor tissue of human prostate. PCA3-TS4 plasmid was created to calculate the absolute amounts of PCA3 transcripts. The androgen regulation of PCA3 and BMCC1 expression was studied in LNCaP and 22Rv1 cells stimulated with 5α-dihydrotestosterone. RESULTS. We have not found any relevant diagnostic advantage of the PCA3-TS4 isoform over the "classical" PCA3 isoform in our group of PrCa patients. Additionally, PCA3-TS4 appears to be only a minor PCA3 transcript. We were also unable to confirm the hypothesis that BMCC1 isoforms are androgen-induced in vitro. CONCLUSIONS. Despite the presence of the recently identified marginal PCA3 transcripts in human PrCa, the previously described major PCA3 isoform still constitutes the best target for diagnostic purposes. PCA3 and BMCC1 are overlapping genes in reverse orientation that do not appear to be co-regulated. © 2009 Wiley-Liss, Inc. Source

Hamid A.R.A.H.,Radboud University Nijmegen | Hamid A.R.A.H.,Radboud Institute for Molecular Life science | Hamid A.R.A.H.,University of Indonesia | Verhaegh G.W.,Radboud University Nijmegen | And 11 more authors.
Journal of Urology

Purpose: Dihydrotestosterone is the main active androgen in the prostate and it has a role in prostate cancer progression. After androgen deprivation therapy androgen receptor signaling is still active in tumor cells. Persistent intratumor steroidogenesis and androgen receptor changes are responsible for this continued activity, which influences the efficacy of prostate cancer treatment. We hypothesized that combining a 5α-reductase inhibitor and an antiandrogen would block intratumor androgen synthesis and androgen receptor protein activity. Thus, it would act synergistically to reduce tumor cell proliferation. Materials and Methods: The expression level of 5α-reductase and androgen receptor in endocrine therapy naïve prostate cancer and castration resistant prostate cancer tissues, and cell line models was determined by microarray and quantitative polymerase chain reaction analysis. Intracellular androgen was measured with radioimmunoassay. Tumor cell proliferation was determined using coloric MTT assay. The synergistic effects of combination treatments on tumor cell proliferation were calculated using the Chou-Talalay equation. Results: In all prostate cancer cases 5α-reductase-1 and 3 were up-regulated. Androgen receptor was up-regulated in metastatic prostate cancer and castration resistant prostate cancer cases. The 5α-reductase inhibitor dutasteride effectively decreased dihydrotestosterone production in prostate cancer and castration resistant prostate cancer cell lines. Furthermore, dutasteride combined with the novel antiandrogen enzalutamide synergistically suppressed endocrine therapy naïve prostate cancer and castration resistant prostate cancer cell proliferation. Conclusions: In this study the combination of a 5α-reductase inhibitor and (novel) antiandrogens synergistically inhibited tumor cell proliferation. These findings support clinical studies of combinations of a 5α-reductase inhibitor and (novel) antiandrogens as first line treatment of prostate cancer and castration resistant prostate cancer. © 2015 American Urological Association Education and Research, Inc. Source

Dijkstra S.,Radboud University Nijmegen | Birker I.L.,University of Amsterdam | Smit F.P.,NovioGendix | Leyten G.H.J.M.,Radboud University Nijmegen | And 5 more authors.
Journal of Urology

Purpose Urinary biomarker tests for diagnosing prostate cancer have gained considerable interest. Urine is a complex mixture that can be subfractionated. We evaluated 2 urinary fractions that contain nucleic acids, ie cell pellets and exosomes. The influence of digital rectal examination before urine collection was also studied and the prostate cancer specific biomarkers PCA3 and TMPRSS2-ERG were assayed. Materials and Methods Urine samples were prospectively obtained before and after digital rectal examination from 30 men scheduled for prostate biopsy. Cell pellet and exosomes were isolated and used for biomarker analysis. Analytical and diagnostic performance was tested using the Student t-test and ROC curves. Results Unlike the exosome fraction, urinary sediment gene expression analysis was compromised by amorphous precipitation in 10% of all specimens. Digital rectal examination resulted in increased mRNA levels in each fraction. This was particularly relevant for the exosomal fraction since after digital rectal examination the number of samples decreased in which cancer specific markers were below the analytical detection limit. Biomarker diagnostic performance was comparable to that in large clinical studies. In exosomes the biomarkers had to be normalized for prostate specific antigen mRNA while cell pellet absolute PCA3 levels had diagnostic value. Conclusions Exosomes have characteristics that enable them to serve as a stable substrate for biomarker analysis. Thus, digital rectal examination enhances the analytical performance of biomarker analysis in exosomes and cell pellets. The diagnostic performance of biomarkers in exosomes differs from that of cell pellets. Clinical usefulness must be prospectively assessed in larger clinical cohorts. © 2014 by AMERICAN UROLOGICAL ASSOCIATION EDUCATION AND RESEARCH, INC. Source

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