In search of the molecular mechanisms mediating the inhibitory effect of the GnRH antagonist degarelix on human prostate cell growth

GNRH2 Polymorphism in Men With Prostate Cancer Treated With Androgen Deprivation Therapy

BACKGROUND/AIM

Gonadotropin-releasing hormone 2 (GNRH2) is a poorly-studied peptide hormone that is widely distributed in the central nervous system and expressed in peripheral tissues of mammals. The non-synonymous rs6051545 variant in GNRH2 (A16V) has been linked to higher serum testosterone concentrations. This study investigated whether the A16V variant is associated with altered androgen-deprivation therapy (ADT) progression-free survival (PFS) and overall survival (OS).

PATIENTS AND METHODS

We examined the expression of GNRH2 in prostate tissue microarrays comprising normal tissue, prostatic hyperplasia, and prostate cancer using immunofluorescence. We also evaluated the GNRH2 genotype in 131 patients with prostate cancer who received ADT and compared PFS and OS between the variant and wild-type genotypes.

RESULTS

GNRH2 was detected in all prostate tissues, although expression did not vary with Gleason grade or disease stage (p=0.71). The GNRH2 A16V genotype was not associated with PFS or OS; however, univariate and multivariate analyses revealed Gleason score and definitive local therapy were each associated with PFS (p≤0.0074), whereas age and Gleason score were associated with OS (p≤0.0046).

CONCLUSION

GNRH2 is expressed in normal, hyperplastic, and neoplastic prostate tissues; the A16V variant is not related to treatment outcome or survival.

Pharmacokinetic, Safety, and Pharmacodynamic Properties of Teverelix Trifluoroacetate, a Novel Gonadotropin-Releasing Hormone Antagonist, in Healthy Adult Subjects

Teverelix trifluoroacetate is a decapeptide, gonadotropin-releasing hormone antagonist that binds competitively and reversibly to gonadotropin-releasing hormone receptors in the pituitary gland, resulting in immediate suppression of luteinizing hormone and follicle-stimulating hormone, which in turn causes a very rapid decrease in testosterone production in the Leydig cells of the testes in men and in estradiol in the ovaries in women. This phase 1 clinical study was an open-label, parallel-design, single-center, single-dose study in older, healthy male subjects. Following injection, teverelix is released into the systemic circulation in a biphasic manner. An initial rapid phase is followed by a slow-release phase thought to be due to the formation of a depot, which limits the diffusion of teverelix into the blood. The release characteristics differ significantly for the subcutaneous (SC) and intramuscular (IM) routes. Teverelix maximum concentration and exposure increased in an approximately dose-proportional manner across the 60 to 120 mg SC doses. All 3 pharmacodynamic end points (luteinizing hormone, follicle-stimulating hormone, and total testosterone) showed reductions that were more prolonged following the 90 mg IM administration compared to 90 mg SC administration.

Zhoushi Qiling decoction induces apoptosis of human prostate cancer cells via miR-143/Bcl-2 axis

A number of traditional Chinese medicines (TCMs) are widely used in prostate cancer treatment in China. The aim of this study was to test the efficacy of a TCM, Zhoushi Qiling Decoction (ZQD), in combination with androgen deprivation therapy (ADT) and explore its underlying mechanism. A total of 151 patients were recruited to receive ADT treatment or ADT+ZQD treatment. The survival of patients who received ADT+ZQD treatment was significantly higher than those who received ADT therapy only. DU145 prostate cancer cells were treated with ZQD (50 mg/mL) for 24 h in vitro and expression levels of an array of miRNAs were examined. Our results suggested that miR-143 demonstrated prominent upregulation in DU145 cells after treatment with ZQD. In patient serum samples, miR-143 expression was also significantly upregulated after ADT+ZQE treatment, which was however absent in patients treated with ADT only. In DU145 cells, ZQD treatment led to a dose-dependent increase in apoptosis, which could be reduced by anti-miR-143 treatment. There was a binding site between miR-143 and B cell CLL/lymphoma-2 (Bcl-2) and ZQD treatment reduced Bcl-2 expression. ZQD treatment led to increased caspase-3 and Bax expression. ZQD treatment could promote apoptosis of prostate cancer cells by promoting miR-143 upregulation, which could be a possible mechanism underlying the inhibitory effect of ZQD in prostate cancer in patient.

Dissecting the Hormonal Signaling Landscape in Castration-Resistant Prostate Cancer

Understanding the molecular mechanisms underlying prostate cancer (PCa) progression towards its most aggressive, castration-resistant (CRPC) stage is urgently needed to improve the therapeutic options for this almost incurable pathology. Interestingly, CRPC is known to be characterized by a peculiar hormonal landscape. It is now well established that the androgen/androgen receptor (AR) axis is still active in CRPC cells. The persistent activity of this axis in PCa progression has been shown to be related to different mechanisms, such as intratumoral androgen synthesis, AR amplification and mutations, AR mRNA alternative splicing, increased expression/activity of AR-related transcription factors and coregulators. The hypothalamic gonadotropin-releasing hormone (GnRH), by binding to its specific receptors (GnRH-Rs) at the pituitary level, plays a pivotal role in the regulation of the reproductive functions. GnRH and GnRH-R are also expressed in different types of tumors, including PCa. Specifically, it has been demonstrated that, in CRPC cells, the activation of GnRH-Rs is associated with a significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic activity. This antitumor activity is mainly mediated by the GnRH-R-associated Gαi/cAMP signaling pathway. In this review, we dissect the molecular mechanisms underlying the role of the androgen/AR and GnRH/GnRH-R axes in CRPC progression and the possible therapeutic implications.

Gonadotropin-Releasing Hormone Receptors in Prostate Cancer: Molecular Aspects and Biological Functions

Pituitary Gonadotropin-Releasing Hormone receptors (GnRH-R) mediate the activity of the hypothalamic decapeptide GnRH, thus playing a key role in the regulation of the reproductive axis. Early-stage prostate cancer (PCa) is dependent on serum androgen levels, and androgen-deprivation therapy (ADT), based on GnRH agonists and antagonists, represents the standard therapeutic approach for PCa patients. Unfortunately, the tumor often progresses towards the more aggressive castration-resistant prostate cancer (CRPC) stage. GnRH receptors are also expressed in CRPC tissues, where their binding to both GnRH agonists and antagonists is associated with significant antiproliferative/proapoptotic, antimetastatic and antiangiogenic effects, mediated by the Gαi/cAMP signaling cascade. GnRH agonists and antagonists are now considered as an effective therapeutic strategy for CRPC patients with many clinical trials demonstrating that the combined use of these drugs with standard therapies (i.e., docetaxel, enzalutamide, abiraterone) significantly improves disease-free survival. In this context, GnRH-based bioconjugates (cytotoxic drugs covalently linked to a GnRH-based decapeptide) have been recently developed. The rationale of this treatment is that the GnRH peptide selectively binds to its receptors, delivering the cytotoxic drug to CRPC cells while sparing nontumor cells. Some of these compounds have already entered clinical trials.

Toward the Rational Design of Universal Dual Polarity Matrix for MALDI Mass Spectrometry

A series of novel anthranilic acid derivatives I-IV, of which COOH-NH₂ (I) and COOH-NHMe (IV) are endowed with acid and base bifunctionality, were designed and synthesized for matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry applications in dual polarity molecular imaging of biological samples, particularly for lipids. The heat of protonation, deprotonation, and proton transfer reaction as well as the capability of analyzing biomolecules in both positive and negative ion modes for I-IV were systematically investigated under standard 355 nm laser excitation. The results indicate correlation between dual polarity and acid-base property. Further, COOH-NHMe (IV) showed a unique performance and was successfully applied as the matrix for MALDI-TOF mass spectrometry imaging (MSI) for studying the mouse brain. Our results demonstrate the superiority of COOH-NHMe (IV) in detecting more lipid and protein species compared to commercially available matrices. Moreover, MALDI-TOF MSI results were obtained for lipid distributions, making COOH-NHMe (IV) a potential next generation universal matrix.

GnRH antagonist treatment of malignant adrenocortical tumors

Aberrantly expressed G protein-coupled receptors in tumors are considered as potential therapeutic targets. We analyzed the expressions of receptors of gonadotropin-releasing hormone (GNRHR), luteinizing hormone/chorionic gonadotropin (LHCGR) and follicle-stimulating hormone (FSHR) in human adrenocortical carcinomas and assessed their response to GnRH antagonist therapy. We further studied the effects of the GnRH antagonist cetrorelix acetate (CTX) on cultured adrenocortical tumor (ACT) cells (mouse Cα1 and Y-1, and human H295R), and in vivo in transgenic mice (SV40 T-antigen expression under inhibin α promoter) bearing Lhcgr and Gnrhr in ACT. Both models were treated with control (CT), CTX, human chorionic gonadotropin (hCG) or CTX+hCG, and their growth and transcriptional changes were analyzed. In situ hybridization and qPCR analysis of human adrenocortical carcinomas (n = 11-13) showed expression of GNRHR in 54/73%, LHCGR in 77/100% and FSHR in 0%, respectively. CTX treatment in vitro decreased cell viability and proliferation, and increased caspase 3/7 activity in all treated cells. In vivo, CTX and CTX+hCG (but not hCG alone) decreased ACT weights and serum LH and progesterone concentrations. CTX treatment downregulated the tumor markers Lhcgr and Gata4. Upregulated genes included Grb10, Rerg, Nfatc and Gnas, all recently found to be abundantly expressed in healthy adrenal vs ACT. Our data suggest that CTX treatment may improve the therapy of human adrenocortical carcinomas by direct action on GNRHR-positive cancer cells inducing apoptosis and/or reducing gonadotropin release, directing tumor cells towards a healthy adrenal gene expression profile.

Automated analysis of lipid drug-response markers by combined fast and high-resolution whole cell MALDI mass spectrometry biotyping

Recent advances in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry have enabled whole cell-MALDI mass spectrometry biotyping of drug-treated cultured cells for rapid monitoring of known abundant pharmacodynamic protein markers such as polyacetylated histones. In contrast, generic and automated analytical workflows for discovery of such pharmacodynamic markers, in particular lipid markers, and their use in cellular tests of drug-like compounds are still lacking. Here, we introduce such a workflow and demonstrate its utility for cellular drug-response monitoring of BCR-ABL tyrosine kinase inhibitors in K562 leukemia cells: First, low-molecular mass features indicating drug responses are computationally extracted from groups of MALDI-TOF mass spectra. Then, the lipids/metabolites corresponding to these features are identified by MALDI-Fourier transformation mass spectrometry. To demonstrate utility of the method, we identify the potassium adduct of phosphatidylcholine PC(36:1) as well as heme B, a marker for erythroid differentiation, as markers for a label-free MALDI MS-based test of cellular responses to BCR-ABL inhibitors. Taken together, these results suggest that MALDI-TOF mass spectrometry of lipids and other low molecular mass metabolites could support cell-based drug profiling.

Activation of human gonadotropin-releasing hormone receptor promotes down regulation of ARHGAP18 and regulates the cell invasion of MDA-MB-231 cells

The Gonadotropin-Releasing Hormone Receptor (GnRHR) is expressed mainly in the gonadotrope membrane of the adenohypophysis and its natural ligand, the Gonadotropin-Releasing Hormone (GnRH), is produced in anterior hypothalamus. Furthermore, both molecules are also present in the membrane of cells derived from other reproductive tissues such as the breast, endometrium, ovary, and prostate, as well as in tumors derived from these tissues. The functions of GnRH receptor and its hormone in malignant cells have been related with the decrease of proliferation and the invasiveness of those tumors however, little is known about the molecules associated with the signaling pathways regulated by both molecules in malignant cells. To further analyze the potential mechanisms employed by the GnRHR/GnRH system to reduce the tumorigenesis of the highly invasive breast cancer cell line MDA-MB-231, we performed microarrays experiments to evaluated changes in genes expression and validate these modifications by functional assays. We show that activation of human GnRHR is able to diminish the expression and therefore functions of the Rho GTPase-Activating Protein 18 (ARHGAP18). Decrease of this GAP following GnRHR activation, correlates to the higher of cell adhesion and also with reduction of tumor cell invasion, supporting the notion that GnRHR triggers intracellular signaling pathways that acts through ARHGAP18. On the contrary, although a decline of cellular proliferation was observed during GnRHR activation in MDA-MB-231, this was independent of ARHGAP18 showing the complex system in which is involved the signaling pathways regulated by the GnRHR/GnRH system.

The combination of Everolimus with Verapamil reduces ovarian weight and vascular permeability on ovarian hyperstimulation syndrome: a preclinical experimental randomized controlled study

The efficacy of pathways inhibition and the combined effect of Everolimus (mTOR inhibitor) and Verapamil (CYP3A inhibitor) in ovarian hyperstimulation syndrome (OHSS) need to be tested. Therefore, the impact of a leucotriene receptor antagonist, an anticoagulant, a GnRH antagonist as well as Everolimus plus Verapamil (at various doses and days of administration) on an OHSS rat model was tested. Sixty three female Wistar rats were randomly divided into seven groups. The control group received saline, while the OHSS group received rec-FSH for four consecutive days. The other five groups received rec-FSH for four days and Montelukast daily, Heparin daily, GnRH antagonist daily, Everolimus plus Verapamil in the last two days (half days group) and Everolimus plus Verapamil (half dose group) daily, respectively. All groups received also hCG at the fifth day. Significantly reduced ovarian weight was observed in the Everolimus plus Verapamil groups (half days and half-dose groups) and the Montelukast group compared to the OHSS group (p = 0.001 and p = 0.001, respectively). The vascular permeability was significantly reduced in the Everolimus plus Verapamil group (half dose group) and the GnRH antagonist group compared to the OHSS group (p < 0.001 and p = 0.011, respectively). However, estradiol and progesterone levels did not differ significantly between the groups. Studying the inhibition of different pathways, we concluded that the co-administration of Everolimus and Verapamil (at half dose) is beneficial for reducing ovarian weight and vascular permeability in an OHSS animal model.

Response of Degarelix treatment in human prostate cancer monitored by HR-MAS 1H NMR spectroscopy

INTRODUCTION

The androgen receptor (AR) is the master regulator of prostate cancer cell metabolism. Degarelix is a novel gonadotrophin-releasing hormone blocker, used to decrease serum androgen levels in order to treat advanced human prostate cancer. Little is known of the rapid metabolic response of the human prostate cancer tissue samples to the decreased androgen levels.

OBJECTIVES

To investigate the metabolic responses in benign and cancerous tissue samples from patients after treatment with Degarelix by using HRMAS 1H NMR spectroscopy.

METHODS

Using non-destructive HR-MAS 1H NMR spectroscopy we analysed the metabolic changes induced by decreased AR signalling in human prostate cancer tissue samples. Absolute concentrations of the metabolites alanine, lactate, glutamine, glutamate, citrate, choline compounds [t-choline = choline + phosphocholine (PC) + glycerophosphocholine (GPC)], creatine compounds [t-creatine = creatine (Cr) + phosphocreatine (PCr)], taurine, myo-inositol and polyamines were measured in benign prostate tissue samples (n = 10), in prostate cancer specimens from untreated patients (n = 7) and prostate cancer specimens from patients treated with Degarelix (n = 6).

RESULTS

Lactate, alanine and t-choline concentrations were significantly elevated in high-grade prostate cancer samples when compared to benign samples in untreated patients. Decreased androgen levels resulted in significant decreases of lactate and t-choline concentrations in human prostate cancer biopsies.

CONCLUSIONS

The reduced concentrations of lactate and t-choline metabolites due to Degarelix could in principle be monitored by in vivo 1H MRS, which suggests that it would be possible to monitor the effects of physical or chemical castration in patients by that non-invasive method.