[Show abstract][Hide abstract] ABSTRACT: Background:
Prostate-specific membrane antigen (PSMA) is a promising target for diagnostics and therapy of prostate carcinoma (PCa). Based on the hypothesis that PSMA expression can be modulated by variations in androgen deprivation therapy (ADT), we investigated the binding of a PSMA-directed radiopharmaceutical in vitro in order to get an insight of the interactions between altered premedication and PSMA expression before repetitive PSMA-directed PET/CT for therapy response and targeted therapy implementation.
The human castration-resistant PCa cell line VCaP (CRPC) was treated with either 1 nmol/L testosterone (T) over 20 passages yielding the androgen-sensitive cell line (revCRPC) or with 5 μmol/L abiraterone acetate (AA) generating the abiraterone-tolerant subtype CRPCAA. In these cell lines, T and AA were varied by either supply or withdrawal of T and AA. PSMA expression of the three cell culture models was detected by Western blot and immunohistochemical staining. For quantitative measurement of tracer uptake, 0.3 nmol/L (68)Ga-labelled PSMA-HBED-CC peptide (100-300 kBq/ml) was added to different treated parallel cultures (n = 9 each). Time-dependent uptake per 10(6) cells of each culture was calculated and evaluated. PSMA mRNA expression was investigated by qPCR.
PSMA expression increased dependently on intensified ADT in all three basic cell lines. (68)Ga-PSMA-HBED-CC uptake almost doubled during 3 h in all cell lines (p < 0.01). Compared to the basic cells, pre-incubation with abiraterone for 48 h resulted in a significant increased uptake in CRPC (p < 0.001). In revCRPC, 48-h AA pre-incubation resulted in an eightfold higher uptake after 3 h (p < 0.001). Additional withdrawal of external testosterone increased the uptake up to tenfold (p < 0.01). The increase of PSMA expression upon ADT and AA treatments was confirmed by qPCR and Western blot data. Furthermore, in CRPCAA, 48-h AA withdrawal increased the uptake up to fivefold (p < 0.01).
The investigated three PCa cell culture subtypes represent a serial preclinical model of androgen deprivation therapy as a proxy for clinical situations with differing basal PSMA expression. The uptake of PSMA-binding tracers could be stimulated by therapeutic effective short-term variation in premedication in all stages of ADT response. These complex interactions have to be considered in the interpretation of diagnostic imaging using PSMA ligands as well as in the optimal timing of PSMA-based therapies.
[Show abstract][Hide abstract] ABSTRACT: Germ cell tumors (GCTs) are the most common malignancies in young men. Most patients with GCT can be cured with cisplatin-based combination chemotherapy, even in metastatic disease. In case of therapy resistance, prognosis is usually poor. We investigated the potential of N-cadherin inhibition as a therapeutic strategy. We analyzed the GCT cell lines NCCIT, NTERA-2, TCam-2, and the cisplatin-resistant sublines NCCIT-R and NTERA-2R. Effects of a blocking antibody or siRNA against N-cadherin on proliferation, migration, and invasion were investigated. Mouse xenografts of GCT cell lines were analyzed by immunohistochemistry for N-cadherin expression. All investigated GCT cell lines were found to express N-cadherin protein in vitro and in vivo. Downregulation of N-cadherin in vitro leads to a significant inhibition of proliferation, migration, and invasion. N-cadherin-downregulation leads to a significantly higher level of pERK. N-cadherin-inhibition resulted in significantly higher rates of apoptotic cells in caspase-3 staining. Expression of N-cadherin is preserved in cisplatin-resistant GCT cells, pointing to an important physiological role in cell survival. N-cadherin-downregulation results in a significant decrease of proliferation, migration, and invasion and stimulates apoptosis in cisplatin-naive and resistant GCT cell lines. Therefore, targeting N-cadherin may be a promising therapeutic approach, particularly in cisplatin-resistant, therapy refractory and metastatic GCT.
[Show abstract][Hide abstract] ABSTRACT: Recent breakthrough therapies targeting androgen receptor signalling in castration resistant prostate cancer (CRPC) involve multifunctional androgen receptor (AR) blockade and exhaustive androgen deprivation. Nevertheless, limitations to an enduring effectiveness of new drugs are anticipated in resistance mechanisms occurring under such treatments.
In this study we used CRPC cell models VCaP and LNCaP as well as AR-negative PC-3- and non-neoplastic epithelial BPH-1-cells treated with 5, 10 or 25 μmol/L abiraterone hydrolyzed from abiraterone acetate (AA). The origin of CYP17A1 up-regulation under AA treatment was investigated in CRPC cell models by qRT-PCR and western-blot procedures.
AA treatments of AR positive CRPC cell models led to decreased expression of androgen regulated genes such as PSA. In these cells diminished expression of androgen regulated genes was accompanied by an up-regulation of CYP17A1 expression within short-term treatments. No such effects became evident in AR-negative PC-3 cells. AR directed siRNA (siAR) used in VCaP cells significantly reduced mRNA expression and AR protein abundance. Such interference with AR signalling in the absence of abiraterone acetate also caused a marked up-regulation of CYP17A1 expression. Down-regulation of androgen regulated genes occurs in spite of an elevated expression of CYP17A1, the very target enzyme for this drug. CYP17A1 up-regulation already takes place within such short treatments with AA and does not require adaptation events over several cell cycles. CYP17A1 is also up-regulated in the absence of AA when AR signalling is physically eliminated by siAR.
These results reveal an immediate counter-regulation of CYP17A1 expression whenever AR-signalling is inhibited adequately but not a persisting adaptation yielding drug resistance.
Electronic supplementary material
The online version of this article (doi:10.1186/2193-1801-3-574) contains supplementary material, which is available to authorized users.
[Show abstract][Hide abstract] ABSTRACT: Phytoestrogens have been shown to exert anti-proliferative effects on different cancer cells. In addition it could be demonstrated that inhibition of proliferation is associated with downregulation of the known stem cell factors NANOG, POU5F1 and SOX2 in tumor cells. We demonstrate the potential of Belamcanda chinensis extract (BCE) and tectorigenin as anticancer drugs in cell lines of malignant testicular germ cell tumor cells (TGCT) by inhibition of proliferation and regulating the expression of stem cell factors. The TGCT cell lines TCam-2 and NTera-2 were treated with BCE or tectorigenin and MTT assay was used to measure the proliferation of tumor cells. In addition, the expression of stem cell factors was analyzed by quantitative PCR and western blot analysis. Furthermore, global expression analysis was performed by microarray technique. BCE and tectorigenin inhibited proliferation and downregulated the stem cell factors NANOG and POU5F1 in TGCT cells. In addition, gene expression profiling revealed induction of genes important for the differentiation and inhibition of oncogenes. Utilizing connectivity map in an attempt to elucidate mechanism underlying BCE treatments we found highly positive association to histone deacetylase inhibitors (HDACi) amongst others. Causing no histone deacetylase inhibition, the effects of BCE on proliferation and stem cell factors may be based on histone-independent mechanisms such as direct hyperacetylation of transcription factors. Based on these findings, phytoestrogens may be useful as new agents in the treatment of TGCT.
Full-text · Article · Aug 2013 · International Journal of Oncology
[Show abstract][Hide abstract] ABSTRACT: Prostate cancer is the leading cause of cancer death in men of the Western world. A castration-resistant prostate cancer (CRPC) eventually will arise when a local restricted prostate carcinoma was not cured duly by radical prostatectomy or radiation therapy. Although androgen ablation therapies are considered the gold standard for treatments of advanced prostate cancer there is no curative therapy available at present. In previous pre-clinical and clinical trials several phytoestrogens were investigated for their anticancer potential in various models for prostate cancer. Phytoestrogens feature tumour preventive characteristics and most probably are involved in the low incidence rate of hormone related cancers in Asian countries. Phytoestrogens such as isoflavones can have a marked impact on the most essential therapy target of CRPC i.e. the androgen receptor. Furthermore, functional analyses solidified the notion of such drugs as androgen antagonistic. Phytoestrogens commonly feature low toxicity combined with a potential of targeted therapy. Thus, these drugs qualify for conceivable implementation in prostate cancer patients under active surveillance. In addition, relapse prevention with these drugs after radical prostatectomy or radiation therapy might be considered.
No preview · Article · Jul 2013 · The Journal of steroid biochemistry and molecular biology
[Show abstract][Hide abstract] ABSTRACT: Unlabelled:
In 1996, the molecular biology of E2 had to be reevaluated: in an effort to identify novel nuclear receptors or unknown isoforms of existing receptors Kuiper and colleague described the expression of a novel subtype of the estrogen receptor (ER) in rat prostate and ovary. Upon this pioneering discovery the already known ER was renamed ERα while the newly described ER was termed ERβ. In this review an attempt is made to summarize the current knowledge regarding the expression and function of ERβ in selected reproductive and non-reproductive organs under physiological conditions. The data suggest that ERβ may be considered as a dominant-negative regulator of ERα modulating transcriptional responses to estrogens. The ratio of ER α vs. β. within a cell may determine the cell sensitivity to estrogens and its biological responses to the hormone.
It is not the ligand, it is the multiplicity of receptors which determines the plethora of estrogen actions. This article is part of a Special Issue entitled 'Phytoestrogens'.
No preview · Article · Mar 2013 · The Journal of steroid biochemistry and molecular biology
[Show abstract][Hide abstract] ABSTRACT: In this study, primary murine prostate cancer (PCa) cells were derived using the well-established TRAMP model (transgenic adenocarcinoma mouse prostate). These PCa cells were treated with the histone deacetylase inhibitor (HDACi), valproic acid (VPA), and we demonstrated that VPA treatment has an anti-migrative, anti-invasive and anti-proliferative effect on PCa cells. Using microarray analyses, we discovered several candidate genes that could contribute to the cellular effects we observed. In the present study we could demonstrate that VPA treatment of PCa cells causes the re-expression of cyclin D2, a known regulator that is frequently lost in PCa as we could show using immunohistochemical analyses on PCa specimens. We demonstrate that VPA specifically induces the re-expression of cyclin D2, one of the highly conserved D-type cyclin family members, in several cancer cell lines with weak or no cyclin D2 expression. Interestingly, VPA treatment had no effect in fibroblasts, which typically have high basal levels of cyclin D2 expression. The re-expression of cyclin D2 observed in PCa cells is activated by increased histone acetylation in the promoter region of the ccnd2 gene and represents one underlying molecular mechanism of VPA treatment that inhibits the proliferation of cancer cells. Altogether, our results confirm that VPA is an anticancer therapeutic drug for the treatment of tumours with epigenetically repressed cyclin D2 expression.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to elucidate whether the treatment of a prostate carcinoma cell line (LNCaP) and LNCaP-derived tumors with the histone deacetylase (HDAC) inhibitor valproate in combination with the mammalian target of rapamycin (mTOR) inhibitor temsirolimus resulted in synergistic effects on cell proliferation and tumor growth. LNCaP cells were treated with valproate, temsirolimus or a combination of both. The proliferation rates and the expression of key markers of tumorigenesis were evaluated. In in vivo experiments, LNCaP cells were implanted into immune-suppressed male nude mice. Mice were treated with valproate (per os), temsirolimus (intravenously) or with a combination of both. Tumor volumes were calculated and mRNA expression was quantified. The incubation of LNCaP cells with the combination of valproate and temsirolimus resulted in a decrease of cell proliferation with an additive effect of both drugs in comparison to the single treatment. In particular, the combined application of valproate and temsirolimus led to a significant upregulation of insulin-like growth factor-binding protein-3 (IGFBP-3), which mediates apoptosis and inhibits tumor cell proliferation. In the mouse model, we found no significant differences in tumor growth between the different treatment arms but immunohistological analyses showed that tumors treated with a combination of valproate and temsirolimus, but not with the single drugs alone, exhibited a significant lower proliferation capacity.
Preview · Article · Dec 2012 · International Journal of Molecular Medicine
[Show abstract][Hide abstract] ABSTRACT: Background
Testicular germ cell tumours (TGCTs) are the most common malignancy in young men aged 18–35 years. They are clinically and histologically subdivided into seminomas and non-seminomas. Cadherins are calcium-dependent transmembrane proteins of the group of adhesion proteins. They play a role in the stabilization of cell-cell contacts, the embryonic morphogenesis, in the maintenance of cell polarity and signal transduction. N-cadherin (CDH2), the neuronal cadherin, stimulates cell-cell contacts during migration and invasion of cells and is able to suppress tumour cell growth.
Tumour tissues were acquired from 113 male patients and investigated by immunohistochemistry, as were the three TGCT cell lines NCCIT, NTERA-2 and Tcam2. A monoclonal antibody against N-cadherin was used.
Tumour-free testis and intratubular germ cell neoplasias (unclassified) (IGCNU) strongly expressed N-cadherin within the cytoplasm. In all seminomas investigated, N-cadherin expression displayed a membrane-bound location. In addition, the teratomas and yolk sac tumours investigated also differentially expressed N-cadherin. In contrast, no N-cadherin could be detected in any of the embryonal carcinomas and chorionic carcinomas examined. This expression pattern was also seen in the investigated mixed tumours consisting of seminomas, teratomas, and embryonal carcinoma.
N-cadherin expression can be used to differentiate embryonal carcinomas and chorionic carcinomas from other histological subtypes of TGCT.
Full-text · Article · Oct 2012 · BMC Clinical Pathology
[Show abstract][Hide abstract] ABSTRACT: Die Androgendeprivation ist die wesentliche Therapie des fortgeschrittenen Prostatakarzinoms. Obwohl sich die Hinweise mehren, dass eine phasenweise Unterbrechung des Hormonentzugs die damit verbundenen Nebenwirkungen vermindern kann, besteht bis heute keine generelle Empfehlung für die intermittierende Hormondeprivation. Vorliegende Metaanalysen von klinischen Studien legen aber den Schluss nahe, dass die Variante der Androgendeprivation einen Gewinn an Lebensqualität bei unvermindertem Therapieerfolg gewähren kann. Zudem zeigen aktuelle präklinische Studien zusätzliches Potenzial einer intermittierenden Androgendeprivation auf. Zukünftige Studien müssen es jedoch noch bestätigen, dass sich diese Therapievarianten am Prostatakarzinompatienten umsetzen lassen.
[Show abstract][Hide abstract] ABSTRACT: In der Prolapschirurgie stehen verschiedenen Operationstechniken zu Verfügung. Die unterschiedlichen Erfolgs- und Rezidivraten sowie operationspezifische Komplikationsrisiken kennzeichnen die verschiedenen offenen, laparoskopischen und vaginalen Techniken. Für eine sichere und optimale Therapie sollte sich der Beckenbodenrepair an den 3 Defektlevels nach DeLancy orientieren und auf jede Patientin individuell abgestimmt sein.
Der vaginale Zugangsweg hat bei jeder Form des weiblichen Genitalprolapses sein Einsatzgebiet und ist gegenüber den anderen Operationsverfahren eine weniger invasive Technik mit einer schnellen Rekonvaleszenz. Er kommt außer bei der Therapie der Belastungsinkontinenz in der primären Anwendung ohne synthetische Netze aus und erreicht sehr gute Ergebnisse mit einer geringen Komplikations- und Rezidivrate. Ein unkritischer Einsatz von Fremdmaterial beim vaginalen „Repair“ sollte vermieden werden. Die abdominalen Operationstechniken (offen oder laparoskopisch) haben ihre Stärken bei der Therapie der hinteren Schadenzone (Level-1-Defekt) und bei der Behandlung der Belastungsinkontinenz. Sie erreichen eine sehr gute funktionelle und anatomische Korrektur und verfügen über eine geringe Rezidivrate. Die abdomial eingesetzten Netze haben eine geringere Komplikationsrate als die vaginalen Meshes.
[Show abstract][Hide abstract] ABSTRACT: Die Nierentumorchirurgie unterliegt einem ständigen Wandel. Als ein Fortschritt in der Therapie von kleineren und mittleren Tumoren der Niere wird heute statt der radikalen Tumornephrektomie, die noch vor einigen Jahren als Standard bei allen Tumoren galt, eine organerhaltende Tumorresektion empfohlen. Die Resektion der Tumoren wird häufig noch unter Ausklemmen der Nierengefäße durchgeführt. Hierbei nimmt man eine warme Ischämie in Kauf. Die Dauer der dabei entstehenden Ischämie ist entscheidend für das Outcome der Nierenrestfunktion. Je kürzer die Ischämiezeit, desto wahrscheinlicher ist eine gute Restfunktion der verbleibende Niere. Daher bedarf es neuer Techniken, die es ermöglichen gänzlich auf ein Ausklemmen der Niere zu verzichten. Diese sollten eine gute Schnittleistung mit einer sicheren Hämostase vereinen. Die bis dato gebräuchlichen Verfahren konnten diese Anforderungen noch nicht hinlänglich erfüllen. Die Etablierung der Lasertechnik in der Urologie ermöglicht nun ein operativ-technisches Verfahren, das eine gute Koagulations- und Schnittleistung in einem verbindet. Die noch spärliche Datenlage zum Einsatz von Laser in der Nierenchirurgie verleiht diesem einen experimentellen Charakter; die bisherigen Ergebnisse sind jedoch durchweg als positiv zu werten. Der Laser bietet sowohl bei der offenen als auch bei der laparoskopischen Nierenteilresektion die Möglichkeit einer sicheren Schnittführung und Hämostase ohne Inkaufnahme zusätzlicher oder vermehrter Komplikationen.
[Show abstract][Hide abstract] ABSTRACT: In prolapse surgery several surgical techniques are available. The different open, laparoscopic and vaginal approaches are distinguished by distinct success and relapse rates and operation-specific complications. A safe and optimal therapeutic pelvic floor surgery should be based on the three support levels according to DeLancy and be individually adjusted for every patient. The vaginal approach may be used for all kinds of female genital prolapse and is a comparatively less invasive technique with a short time of convalescence. Apart from stress incontinence there is no need for synthetic meshes in primary approaches and excellent results with low complication and relapse rates can be achieved. An uncritical application of synthetic material is to be avoided in vaginal repair at all times. Abdominal surgical techniques, both open and laparoscopic, present their strengths in the therapeutic approach to level 1 defects or stress incontinence. They provide excellent functional and anatomical corrections and low relapse rates. Abdominally inserted meshes have lower complication rates than vaginal ones.
[Show abstract][Hide abstract] ABSTRACT: Androgen deprivation is the predominant therapy for advanced prostate cancer. There is accumulating evidence that phases of intermission in androgen deprivation may have benefits regarding side effects, albeit there is as yet no general recommendation for intermittent androgen deprivation therapy. Recent systematic reviews at least substantiate a benefit from such regimens for general quality of life without therapy compromisation. In addition, preclinical data revealed further potential strategies for intermittent androgen deprivation therapy. Future studies must prove, however, that such approaches can be implemented in the clinical situation.
[Show abstract][Hide abstract] ABSTRACT: Kidney surgery is subject to continuous change. Partial nephrectomy is the prevailing method for small and medium-sized tumours and proven to be superior to radical nephrectomy. The conventional technique usually includes clamping the renal vessels. The duration of the ischaemia caused determines the outcome of the remaining renal function. The shorter the ischaemic time the more likely the renal function will be preserved. Thus, new techniques are needed to abandon renal vessel clamping. Essential is a combination of good cutting abilities and assured haemostasis. To date, the commonly used techniques for cutting in partial nephrectomy only partially fulfil these requirements. Establishment of laser in urology offers a new surgical technique that combines both. In spite of the still limited data on laser use in kidney surgery, this method can be assessed favourably. Laser offers a possibility of both open and laparoscopic partial nephrectomy avoiding renal vessel clamping without additional risks or complications.
[Show abstract][Hide abstract] ABSTRACT: Increasing evidence suggests an important function of the β-amyloid precursor protein (APP) in malignant disease in humans; however, the biological basis for this evidence is not well understood at present. To understand the role of APP in transformed pluripotent stem cells, we studied its expression levels in human testicular germ cell tumors using patient tissues, model cell lines, and an established xenograft mouse model. In the present study, we demonstrate the cooperative expression of APP with prominent pluripotency-related genes such as Sox2, NANOG, and POU5F1 (Oct3/4). The closest homologue family member, APLP2, showed no correlation to these stem cell factors. In addition, treatment with histone deacetylase (HDAC) inhibitors suppressed the levels of APP and stem cell markers. Loss of pluripotency, either spontaneously or as a consequence of treatment with an HDAC inhibitor, was accompanied by decreased APP protein levels both in vitro and in vivo. These observations suggest that APP represents a novel and specific biomarker in human transformed pluripotent stem cells that can be selectively modulated by HDAC inhibitors.
Full-text · Article · Feb 2012 · American Journal Of Pathology
[Show abstract][Hide abstract] ABSTRACT: Testicular germ cell tumours (TGCTs) are the most common malignancy in young men aged 18-35 years. They are clinically and histologically subdivided into seminomas and non-seminomas. 1,25-Dihydroxyvitamin D (1,25(OH)(2)D(3)) is the active form of vitamin D and exerts its actions via a specific intracellular vitamin D receptor (VDR). Several investigations in the recent years have revealed, in addition to a physiological occurrence of the VDR in various tissues, VDR expression in different human malignancies. Furthermore, 1,25(OH)(2)D(3) plays an important role in the regulation of cell proliferation and differentiation. In different normal and malignant cell types, antiproliferative and pro-differentiating effects of 1,25(OH)(2)D(3) are described. We investigated whether TGCT express the VDR, wether differences exist between the histological subtypes and if vitamin D has a function on the proliferation of tumour cells. Furthermore, we investigated the potential function of the vitamin D-regulated genes nuclear receptor co-repressor 1(NCOR1), nuclear receptor co-repressor 2 (NCOR2), thyroid receptor interacting protein 15 (TRIP15), Growth Arrest and DNA Damage (GADD45), MAP kinase-activated protein kinase 2 (MAPKAPK2), Cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) and Cytochrome P450, family 27, subfamily B, polypeptide 1 (CYP27B1) in the pathogenesis of TGCT. We demonstrate, for the first time, that primary TGCT as well as TGCT cell lines, express VDR mRNA and protein. Vitamin D and VDR may play a role in the pathogenesis of TGCTs. Furthermore, vitamin D inhibits proliferation of TGCT cell-lines, potentially via an increase in expression of GADD45. Our data suggest that vitamin D could play a role in antitumour therapy.
No preview · Article · Jan 2012 · Anticancer research
[Show abstract][Hide abstract] ABSTRACT: Various antiepileptic drugs such as valproic acid, carbamazepine, oxcarbazepine, lamotrigine and levetiracetam are known to exert histone deacetylase inhibitory (HDACi) properties, which can modify aberrantly silenced gene expression by an epigenetic mechanism. This study was initiated to examine a potential beneficial effect of these drugs on prostate cancer (PC) development. The prostate-specific antigen (PSA) levels of 106 patients under long-term treatment with antiepileptic drugs and known HDACi properties were examined. PSA represents a hallmark in the early detection of PC, and its levels may predict an invasive disease in subsequent years. For in-vitro experiments, the PC cell line LNCaP was treated with HDACi drugs; subsequently, PSA and further PC markers were assessed. When men over 50 years of age were treated with HDACi drugs they had lower age-corrected PSA levels compared with control groups, according to the following ranking: valproic acid>levetiracetam>carbamazepine/oxcarbazepine>lamotrigine. Furthermore, there was a correlation between PSA reduction and the number of HDACi drugs within the medication, lending credence to the idea that a synergistic effect might be possible. Moreover, in vitro, HDACi drugs decrease PSA on mRNA and protein levels and exhibit further oncoprotective properties.The fact that HDACi drugs exert antiproliferative effects on neoplastic cells in vitro and in vivo, which are paralleled by expression alterations of aberrantly regulated genes, underlines the potential therapeutic value of HDACi drugs. These data suggest that long-term HDACi treatment can positively influence the characteristically slow transformation of tumour precursor cells in the prostate and may thus reduce a patient's risk of developing PC.
No preview · Article · Jan 2012 · European journal of cancer prevention: the official journal of the European Cancer Prevention Organisation (ECP)