HORMONE-REFRACTORY PROSTATE CANCER CELLS EXPRESS FUNCTIONAL FOLLICLE-STIMULATING HORMONE RECEPTOR (FSHR)

A Model-Informed Drug Development Approach to Design a Phase 3 Trial of Teverelix Drug Product in Advanced Prostate Cancer Patients with Increased Cardiovascular Risk

Teverelix drug product (DP) is a parenteral gonadotropin-releasing hormone (GnRH) antagonist that has been successfully tested in phase 2 trials for hormone-sensitive advanced prostate cancer (APC) and benign prostatic hyperplasia (BPH). In previous APC trials, teverelix DP was administered as intramuscular (IM) and subcutaneous (SC) injections, using a loading dose and (in a single trial) a maintenance dose. Our objective was to derive an optimal dosing regimen for phase 3 clinical development, using a pharmacometrics modeling approach. Data from 9 phase 2 studies (229 patients) was utilized to develop a population pharmacokinetic (PK) model that described the concentration profile accommodating both IM and SC routes of administration. A 2-compartment model with sequential first-order absorption (slow and fast) and lag times best described the PK profiles of teverelix following SC and IM administration. An indirect response model with inhibition of production rate was fit to describe testosterone (T) concentrations based on physiological relevance. The final population PK-pharmacodynamic model was used to conduct simulations of various candidate dosing regimens to select the optimal dosing regimen to achieve clinical castration (T < 0.5 ng/mL by day 28) and to sustain clinical castration for 26 weeks. Model simulation showed that a loading dose of 360 mg SC and 180 mg IM with a maintenance dose of 360 mg SC 6-weekly (Q6W) starting at day 28 can achieve a ≥95% castration rate up to 52 weeks. This dose regimen was selected for phase 3 clinical development, which includes cardiovascular safety assessment in comparison to a GnRH agonist.

Extra-Gonadal and Non-Canonical Effects of FSH in Males

Recombinant follicle-stimulating hormone (FSH) is commonly used for the treatment of female infertility and is increasingly being used in males as well, as recommended by notable guidelines. FSH is composed of an α subunit, shared with other hormones, and a β subunit, which confers specificity of biological action by interacting with its surface receptor (FSHR), predominantly located in granulosa and Sertoli cells. However, FSHRs also exist in extra-gonadal tissues, indicating potential effects beyond male fertility. Emerging evidence suggests that FSH may have extra-gonadal effects, including on bone metabolism, where it appears to stimulate bone resorption by binding to specific receptors on osteoclasts. Additionally, higher FSH levels have been associated with worse metabolic and cardiovascular outcomes, suggesting a possible impact on the cardiovascular system. FSH has also been implicated in immune response modulation, as FSHRs are expressed on immune cells and may influence inflammatory response. Furthermore, there is growing interest in the role of FSH in prostate cancer progression. This paper aims to provide a comprehensive analysis of the literature on the extra-gonadal effects of FSH in men, with a focus on the often-conflicting results reported in this field. Despite the contradictory findings, the potential for future development in this area is substantial, and further research is needed to elucidate the mechanisms underlying these effects and their clinical implications.

Impact of add-back FSH on human and mouse prostate following gonadotropin ablation by GnRH antagonist treatment

OBJECTIVE

During androgen ablation in prostate cancer by the standard gonadotropin-releasing hormone (GnRH) agonist treatment, only luteinizing hormone (LH) is permanently suppressed while circulating follicle-stimulating hormone (FSH) rebounds. We explored direct prostatic effects of add-back FSH, after androgen ablation with GnRH antagonist, permanently suppressing both gonadotropins.

METHODS

The effects of recombinant human (rFSH) were examined in mice treated with vehicle (controls), GnRH antagonist degarelix (dgx), dgx + rFSH, dgx + flutamide, or dgx + rFSH + flutamide for 4 weeks. Prostates and testes size and expression of prostate-specific and/or androgen-responsive genes were measured. Additionally, 33 young men underwent dgx-treatment. Seventeen were supplemented with rFSH (weeks 1-5), and all with testosterone (weeks 4-5). Testosterone, gondotropins, prostate-specific antigen (PSA), and inhibin B were measured.

RESULTS

In dgx and dgx + flutamide treated mice, prostate weight/body weight was 91% lower than in controls, but 41 and 11%, respectively, was regained by rFSH treatment (P = 0.02). The levels of seminal vesicle secretion 6, Pbsn, Nkx3.1, beta-microseminoprotein, and inhibin b were elevated in dgx + rFSH-treated animals compared with only dgx treated (all P < 0.05). In men, serum inhibin B rose after dgx treatment but was subsequently suppressed by testosterone. rFSH add-back had no effect on PSA levels.

CONCLUSIONS

These data provide novel evidence for the direct effects of FSH on prostate size and gene expression in chemically castrated mice. However, in chemically castrated men, FSH had no effect on PSA production. Whether FSH effects on the prostate in humans also require suppression of the residual adrenal-derived androgens and/or a longer period of rFSH stimulation, remains to be explored.

Follicle-stimulating hormone promotes growth of human prostate cancer cell line-derived tumor xenografts

Chemical castration in prostate cancer can be achieved with gonadotropin-releasing hormone (GnRH) agonists or antagonists. Their effects differ by the initial flare of gonadotropin and testosterone secretion with agonists and the immediate pituitary-testicular suppression by antagonists. While both suppress luteinizing hormone (LH) and follicle-stimulating hormone (FSH) initially, a rebound in FSH levels occurs during agonist treatment. This rebound is potentially harmful, taken the expression of FSH receptors (R) in prostate cancer tissue. We herein assessed the role of FSH in promoting the growth of androgen-independent (PC-3, DU145) and androgen-dependent (VCaP) human prostate cancer cell line xenografts in nude mice. Gonadotropins were suppressed with the GnRH antagonist degarelix, and effects of add-back human recombinant FSH were assessed on tumor growth. All tumors expressed GnRHR and FSHR, and degarelix treatment suppressed their growth. FSH supplementation reversed the degarelix-evoked suppression of PC-3 tumors, both in preventive (degarelix and FSH treatment started upon cell inoculation) and therapeutic (treatments initiated 3 weeks after cell inoculation) setting. A less marked, though significant FSH effect occurred in DU145, but not in VCaP xenografts. FSHR expression in the xenografts supports direct FSH stimulation of tumor growth. Testosterone supplementation, to maintain the VCaP xenografts, apparently masked the FSH effect on their growth. Treatment with the LH analogue hCG did not affect PC-3 tumor growth despite their expression of luteinizing hormone/choriongonadotropin receptor. In conclusion, FSH, but not LH, may directly stimulate the growth of androgen-independent prostate cancer, suggesting that persistent FSH suppression upon GnRH antagonist treatment offers a therapeutic advantage over agonist.

Progress in Clinical Research on Gonadotropin-Releasing Hormone Receptor Antagonists for the Treatment of Prostate Cancer

Gonadotropin-releasing hormone (GnRH) receptor agonists are still the most commonly used androgen deprivation treatment (ADT) drugs for prostate cancer in clinical practice. Currently, the GnRH receptor antagonists used for endocrine therapy for prostate cancer primarily include degarelix and relugolix (TAK-385). The former is administered by subcutaneous injection, while the latter is an oral drug. Compared to GnRH agonists, GnRH antagonists reduce serum testosterone levels more rapidly without an initial testosterone surge or subsequent microsurges. This review focuses on the mechanism of action of GnRH antagonists and agonists, the developmental history of GnRH antagonists, and emerging data from clinical studies of the two antagonists used as endocrine therapy for prostate cancer.

Follicle-Stimulating Hormone Induces Lipid Droplets via Gαi/o and β-Arrestin in an Endometrial Cancer Cell Line

Follicle-stimulating hormone (FSH) and its G protein-coupled receptor, FSHR, represents a paradigm for receptor signaling systems that activate multiple and complex pathways. Classically, FSHR activates Gαs to increase intracellular levels of cAMP, but its ability to activate other G proteins, and β-arrestin-mediated signaling is well documented in many different cell systems. The pleiotropic signal capacity of FSHR offers a mechanism for how FSH drives multiple and dynamic downstream functions in both gonadal and non-gonadal cell types, including distinct diseases, and how signal bias may be achieved at a pharmacological and cell system-specific manner. In this study, we identify an additional mechanism of FSH-mediated signaling and downstream function in the endometrial adenocarcinoma Ishikawa cell line. While FSH did not induce increases in cAMP levels, this hormone potently activated pertussis toxin sensitive Gαi/o signaling. A selective allosteric FSHR ligand, B3, also activated Gαi/o signaling in these cells, supporting a role for receptor-mediated activation despite the low levels of FSHR mRNA. The low expression levels may attribute to the lack of Gαs/cAMP signaling as increasing FSHR expression resulted in FSH-mediated activation of the Gαs pathway. Unlike prior reports for FSH-mediated Gαs/cAMP signaling, FSH-mediated Gαi/o signaling was not affected by inhibition of dynamin-dependent receptor internalization. While chronic FSH did not alter cell viability, FSH was able to increase lipid droplet size. The β-arrestins are key adaptor proteins known to regulate FSHR signaling. Indeed, a rapid, FSH-dependent increase in interactions between β-arrestin1 and Gαi1 was observed via NanoBiT complementation in Ishikawa cells. Furthermore, both inhibition of Gαi/o signaling and siRNA knockdown of β-arrestin 1/2 significantly reduced FSH-induced lipid droplet accumulation, implying a role for a Gαi/o/β-arrestin complex in FSH functions in this cell type. As FSH/FSHR has been implicated in distinct hormone-dependent cancers, including endometrial cancer, analysis of the cancer genome database from 575 human endometrial adenocarcinoma tumors revealed that a subpopulation of samples expressed FSHR. Overall, this study highlights a novel mechanism for FSHR signal pleiotropy that may be exploited for future personalized therapeutic approaches.

Activation of GPR56, a novel adhesion GPCR, is necessary for nuclear androgen receptor signaling in prostate cells

The androgen receptor (AR) is activated in patients with castration resistant prostate cancer (CRPC) despite low circulating levels of androgen, suggesting that intracellular signaling pathways and non-androgenic factors may contribute to AR activation. Many G-protein coupled receptors (GPCR) and their ligands are also activated in these cells indicating that they may play a role in development of Prostate Cancer (PCa) and CRPC. Although a cross talk has been suggested between the two pathways, yet, the identity of GPCRs which may play a role in androgen signaling, is not established yet. By using blast analysis of 826 GPCRs, we identified a GPCR, GPCR 205, which exhibited maximum similarity with the ligand binding domain of the AR. We demonstrate that adhesion GPCR 205, also known as GPR56, can be activated by androgens to stimulate the Rho signaling pathway, a pathway that plays an important role in prostate tumor cell metastasis. Testosterone stimulation of GPR56 also activates the cAMP/ Protein kinase A (PKA) pathway, that is necessary for AR signaling. Knocking down the expression of GPR56 using siRNA, disrupts nuclear translocation of AR and transcription of prototypic AR target genes such as PSA. GPR56 expression is higher in all twenty-five prostate tumor patient's samples tested and cells expressing GPR56 exhibit increased proliferation. These findings provide new insights about androgen signaling and identify GPR56 as a possible therapeutic target in advanced prostate cancer patients.

Oral Relugolix for Androgen-Deprivation Therapy in Advanced Prostate Cancer

BACKGROUND

Injectable luteinizing hormone-releasing hormone agonists (e.g., leuprolide) are the standard agents for achieving androgen deprivation for prostate cancer despite the initial testosterone surge and delay in therapeutic effect. The efficacy and safety of relugolix, an oral gonadotropin-releasing hormone antagonist, as compared with those of leuprolide are not known.

METHODS

In this phase 3 trial, we randomly assigned patients with advanced prostate cancer, in a 2:1 ratio, to receive relugolix (120 mg orally once daily) or leuprolide (injections every 3 months) for 48 weeks. The primary end point was sustained testosterone suppression to castrate levels (<50 ng per deciliter) through 48 weeks. Secondary end points included noninferiority with respect to the primary end point, castrate levels of testosterone on day 4, and profound castrate levels (<20 ng per deciliter) on day 15. Testosterone recovery was evaluated in a subgroup of patients.

RESULTS

A total of 622 patients received relugolix and 308 received leuprolide. Of men who received relugolix, 96.7% (95% confidence interval [CI], 94.9 to 97.9) maintained castration through 48 weeks, as compared with 88.8% (95% CI, 84.6 to 91.8) of men receiving leuprolide. The difference of 7.9 percentage points (95% CI, 4.1 to 11.8) showed noninferiority and superiority of relugolix (P<0.001 for superiority). All other key secondary end points showed superiority of relugolix over leuprolide (P<0.001). The percentage of patients with castrate levels of testosterone on day 4 was 56.0% with relugolix and 0% with leuprolide. In the subgroup of 184 patients followed for testosterone recovery, the mean testosterone levels 90 days after treatment discontinuation were 288.4 ng per deciliter in the relugolix group and 58.6 ng per deciliter in the leuprolide group. Among all the patients, the incidence of major adverse cardiovascular events was 2.9% in the relugolix group and 6.2% in the leuprolide group (hazard ratio, 0.46; 95% CI, 0.24 to 0.88).

CONCLUSIONS

In this trial involving men with advanced prostate cancer, relugolix achieved rapid, sustained suppression of testosterone levels that was superior to that with leuprolide, with a 54% lower risk of major adverse cardiovascular events. (Funded by Myovant Sciences; HERO ClinicalTrials.gov number, NCT03085095.).

Cardiovascular risk with androgen deprivation therapy

BACKGROUND

From the primary care perspective, many urologists and oncologists appear to be ignoring an FDA warning to assess patients' cardiovascular (CV) risk before instituting androgen deprivation therapy (ADT) with gonadotropin-releasing hormone (GnRH) agonists. A growing body of data suggest an association between ADT and CV/cardiometabolic risk, particularly for GnRH agonists.

METHODOLOGY

The author examined available evidence regarding CV side effects with GnRH agonists and antagonists to determine what urologists, medical oncologists, primary care physicians (PCPs) and patients need to know about these risks.

RESULTS

Data are inconclusive and somewhat conflicting-for example, both low testosterone and testosterone replacement have been associated with elevated CV risk. But the distinction between GnRH agonists and antagonists is becoming clearer, as agonists appear to be more strongly linked with CV risk, perhaps due to the transient testosterone surge they cause upon administration. Moreover, adverse CV events associated with GnRH agonists can emerge relatively quickly, within weeks to months. Conversely, two studies show that GnRH antagonists may significantly reduce CV risk compared to GnRH agonists.

CONCLUSIONS

Both GnRH agonists and antagonists carry some degree of CV risk. Although the risk appears to be lower with GnRH antagonists, urologists and oncologists should communicate with PCPs to determine patients' baseline CV risk levels before implementing ADT with either type of agent.

FSH Beyond Fertility

The traditional view of follicle-stimulating hormone (FSH) as a reproductive hormone is changing. It has been shown that FSH receptors (FSHRs) are expressed in various extra-gonadal tissues and mediate the biological effects of FSH at those sites. Molecular, animal, epidemiologic, and clinical data suggest that elevated serum FSH may play a significant role in the evolution of bone loss and obesity, as well as contributing to cardiovascular and cancer risk. This review summarizes recent data on FSH action beyond reproduction.

Extragonadal FSHR Expression and Function-Is It Real?

Expression of the follicle-stimulating hormone receptor (FSHR), besides gonadal tissues, has recently been detected in several extragonadal normal and tumorous tissues, including different types of primary and metastatic cancer and tumor vessel endothelial cells (TVEC). The suggested FSH actions in extragonadal tissues include promotion of angiogenesis, myometrial contractility, skeletal integrity, and adipose tissue accumulation. Non-malignant cells within cancer tissue have been shown to be devoid of FSHR expression, which implies a potential role of FSHR as a diagnostic, prognostic, or even a therapeutic tool. There are shared issues between several of the published reports questioning the validity of some of the conclusion. Firstly, protein expression of FSHR was performed solely with immunohistochemistry (IHC) using either an unavailable "in house" FSHR323 monoclonal antibody or poorly validated polyclonal antibodies, usually without additional methodological quality control and confirmations. Secondly, there is discrepancy between the hardly traceable or absent FSHR gene amplification/transcript data and non-reciprocal strong FSHR protein immunoreactivity. Thirdly, the pharmacological high doses of recombinant FSH used in in vitro studies also jeopardizes the physiological or pathophysiological meaning of the findings. We performed in this review a critical analysis of the results presenting extragonadal expression of FSHR and FSH action, and provide a rationale for the validation of the reported results using additional more accurate and sensitive supplemental methods, including in vivo models and proper positive and negative controls.

Cell-based evidence regarding the role of FSH in prostate cancer

INTRODUCTION

Conversion of androgen-responsive prostate cancer (CaP) to castration-resistant CaP is associated with an acceleration of the disease that often requires treatment modalities other than androgen deprivation therapy only. Recently, follicle-stimulating hormone (FSH) has been shown to play a role in CaP growth, and clinical data showed that high serum concentration of FSH in chemically castrated CaP patients was associated with a shorter time of progression to castration-resistant CaP. In this study, we sought to investigate if FSH could have direct effects on CaP cells, possibly through the androgen receptor and androgen receptor regulated genes, such as prostate-specific antigen (PSA).

MATERIALS AND METHODS

The human CaP cell lines PC-3, LNCaP and C4-2, and nonmalignant PNT1A cells, were utilized to investigate the effects of FSH. qPCR, Western blotting analysis, and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymetoxyphenyl)-2-(4-sulfophenyl)-2H tetrazolium assays were performed in order to analyze the FSH effects.

RESULTS

The FSH receptor was present in all cell lines except PNT1A. FSH significantly increased PSA mRNA (P < 0.01) and protein (P < 0.03) levels in C4-2 cells in a dose-dependent manner. In LNCaP cells, FSH also increased PSA protein level, although to a lesser extent than in C4-2 cells, and the expression was reduced by the antiandrogen enzalutamide. In PC-3 cells, FSH was shown to increase their proliferation (P < 0.03) and β-catenin expression.

CONCLUSION

These findings demonstrate that FSH may have a direct effect in CaP in an androgen-depleted environment. However, further research is needed to understand the significance of direct FSH action in the maintenance of CaP growth at the different phases of transition from androgen dependence to androgen independence.

Molecular and functional insights into gonadotropin hormone receptor dimerization and oligomerization

The gonadotropin hormones, follicle stimulating hormone and luteinizing hormone, are essential for reproduction. They work in concert to control multiple aspects of gonadal function to ultimately produce meiotically competent and fertilizable gametes, provide the optimal endometrial environment and support for implantation and maintain pregnancy via progesterone production throughout the first trimester of pregnancy. These complex and multidimensional functions are mediated via the gonadotropin hormone receptors, luteinizing hormone receptor and follicle stimulating hormone receptor, Class A G protein-coupled receptors (GPCR), which couple to multiple G protein-dependent and independent signal pathways to control these physiological processes. Over the last two decades, a plethora of experimental evidence has shown that GPCRs can associate to form dimers and oligomers. This association provides a means of mediating the diverse functional requirements of a single receptor subtype and for the gonadotropin hormone receptors, has been shown to alter the pharmacology and signal activation profile of these receptors. This review will detail the historical and current evidence detailing the formation of gonadotropin hormone receptor homomers and heteromers. We will discuss the functional insights gained from in vitro and in vivo studies, and the potential impact in modulating reproductive health and disease.

Vascular Endothelial FSH Receptor, a Target of Interest for Cancer Therapy

Improved molecular understanding of tumor microenvironment has resulted in the identification of various cancer cell targets for diagnostic and therapeutic interventions, including the receptor for the FSH, a glycoprotein hormone responsible for growth, maturation, and function of human reproductive system. The expression and localization of the FSH receptor (FSHR)-protein were associated with the tumor epithelial cells and/or with the peripheral tumor blood vessels. The available evidence indicates that in ovarian cancer, prostate cancer, and breast cancer, the tumor epithelial FSHR promotes proliferation, migration, and invasion of cancer cells. The vascular endothelial FSHR, detected in 11 types of solid tumors and 11 types of sarcomas, is involved in receptor-mediated transendothelial transport of FSH, tumor angiogenesis, and vascular remodeling. In contrast to intratumor vessels, which are abnormal and disorganized, the FSHR-positive blood microvessels are arranged in a hierarchical pattern: arterioles-capillaries-venules. The FSHR-positive blood vessels make connections between the intratumor vessels and the general blood circulation of patients. In this mini-review, I summarize these studies and discuss the rationale for developing a strategy for cancer therapy based on FSHR expressed on the luminal endothelial cell surface of blood vessels located in the peritumoral area rather than endothelial markers expressed in the core of tumors. Because FSHR is a common marker of peritumoral vessels, therapeutic agents coupled to anti-FSHR humanized antibodies should in principle be applicable to a wide range of tumor types.

Regulation of prostate cancer by hormone-responsive G protein-coupled receptors

Regulation of prostate cancer by androgen and androgen receptor (AR), and blockade of AR signaling by AR antagonists and steroidogenic enzyme inhibitors have been extensively studied. G protein-coupled receptors (GPCRs) are a family of membrane receptors that regulate almost all physiological processes. Nearly 40% of FDA-approved drugs in the market target GPCRs. A variety of GPCRs that mediate reproductive function have been demonstrated to be involved in the regulation of prostate cancer. These GPCRs include gonadotropin-releasing hormone receptor, luteinizing hormone receptor, follicle-stimulating hormone receptor, relaxin receptor, ghrelin receptor, and kisspeptin receptor. We highlight here GPCR regulation of prostate cancer by these GPCRs. Further therapeutic approaches targeting these GPCRs for the treatment of prostate cancer are summarized.

Antibody Selection for Cancer Target Validation of FSH-Receptor in Immunohistochemical Settings

BACKGROUND

The follicle-stimulating hormone (FSH)-receptor (FSHR) has been reported to be an attractive target for antibody therapy in human cancer. However, divergent immunohistochemical (IHC) findings have been reported for FSHR expression in tumor tissues, which could be due to the specificity of the antibodies used.

METHODS

Three frequently used antibodies (sc-7798, sc-13935, and FSHR323) were validated for their suitability in an immunohistochemical study for FSHR expression in different tissues. As quality control, two potential therapeutic anti-hFSHR Ylanthia® antibodies (Y010913, Y010916) were used. The specificity criteria for selection of antibodies were binding to native hFSHR of different sources, and no binding to non-related proteins. The ability of antibodies to stain the paraffin-embedded Flp-In Chinese hamster ovary (CHO)/FSHR cells was tested after application of different epitope retrieval methods.

RESULTS

From the five tested anti-hFSHR antibodies, only Y010913, Y010916, and FSHR323 showed specific binding to native, cell-presented hFSHR. Since Ylanthia® antibodies were selected to specifically recognize native FSHR, as required for a potential therapeutic antibody candidate, FSHR323 was the only antibody to detect the receptor in IHC/histochemical settings on transfected cells, and at markedly lower, physiological concentrations (ex., in Sertoli cells of human testes). The pattern of FSH323 staining noticed for ovarian, prostatic, and renal adenocarcinomas indicated that FSHR was expressed mainly in the peripheral tumor blood vessels.

CONCLUSION

Of all published IHC antibodies tested, only antibody FSHR323 proved suitable for target validation of hFSHR in an IHC setting for cancer. Our studies could not confirm the previously reported FSHR overexpression in ovarian and prostate cancer cells. Instead, specific overexpression in peripheral tumor blood vessels could be confirmed after thorough validation of the antibodies used.

Follicle-Stimulating Hormone Receptor (FSHR): A Promising Tool in Oncology?

The cellular pathway of follicle-stimulating hormone (FSH) and its receptor (FSHR) is typically involved in reproduction in mammals. In humans, the FSHR is normally found in cells of the testis and the ovary, while it is scarcely expressed in other normal tissues. The expression of FSH/FSHR is studied in prostate, thyroid, and ovarian cancer tissues. Recently, the expression of FSHR was uniformly documented in malignant vascular endothelial cells from different tumor types, while in normal or inflammatory tissues its expression was scarce, suggesting a potential role of a pan-receptor in cancer. Subsequent studies have attempted to verify this unique specificity of this molecule and further define its features in malignant microenvironments but have had conflicting results, mostly because of differing techniques and immaturity of antibodies. Still, the lack of FSHR expression in most non-cancerous cells, in contrast to its specific correlation with the malignant tissue microenvironment, implies a potential role as both a diagnostic and a therapeutic tool. FSHR might also have a very specific role in malignancies, such as angiogenic and/or growth factor malignancies, but this is yet to be validated. Moreover, the expression of FSHR in endothelial malignant cells could have a predictive impact on disease progression, especially in relation to therapies targeting the tumor vasculature. In this review we look deep into the physiology of the FSH/FSHR pathway and evaluate the potential of FSHR as a predictive and prognostic tool in oncology.

The potential role of follicle-stimulating hormone in the cardiovascular, metabolic, skeletal, and cognitive effects associated with androgen deprivation therapy

PURPOSE

To explore how follicle-stimulating hormone (FSH) may contribute to cardiovascular, metabolic, skeletal, and cognitive events in men treated for prostate cancer, with various forms of androgen deprivation therapy (ADT).

MATERIALS AND METHODS

A colloquium of prostate cancer experts was convened in May 2015, to discuss the role of FSH in the development of unwanted effects associated with ADT. Subsequently, a literature review (Medline, PubMed, and relevant congress abstract databases) was performed to further explore and evaluate the collected evidence.

RESULTS

It has become evident that, in the setting of ADT, FSH can promote the development of atherosclerotic plaque formation, metabolic syndrome, and insulin resistance. Data also suggest that FSH is an important mediator of bone remodeling, particularly bone resorption, and thereby increases the risk for bone fracture. Additional evidence implicates a role for FSH in bone metastasis as well. The influence of FSH on ADT-induced cognitive deficits awaits further elucidation; however, the possibility that FSH may be involved therein cannot be ruled out.

CONCLUSIONS

The widespread molecular and physiological consequences of FSH system activation in normal and pathological conditions are becoming better understood. Progress in this area has been achieved by the development of additional investigative and clinical measures to better evaluate specific adverse effects. More research is needed on FSH function in the development of cancer as well as its association with cardiovascular, metabolic, musculoskeletal, and cognitive effects in ADT.

A Phase II, Randomized, Open-Label Study of Neoadjuvant Degarelix versus LHRH Agonist in Prostate Cancer Patients Prior to Radical Prostatectomy

Purpose: Degarelix, a new gonadotropin-releasing hormone (GnRH) receptor antagonist with demonstrated efficacy as first-line treatment in the management of high-risk prostate cancer, possesses some theoretical advantages over luteinizing hormone-releasing hormone (LHRH) analogues in terms of avoiding "testosterone flare" and lower follicle-stimulating hormone (FSH) levels. We set out to determine whether preoperative degarelix influenced surrogates of disease control in a randomized phase II study.Experimental Design: Thirty-nine patients were randomly assigned to one of three different neoadjuvant arms: degarelix only, degarelix/bicalutamide, or LHRH agonist/bicalutamide. Treatments were given for 3 months before prostatectomy. Patients had localized prostate cancer and had chosen radical prostatectomy as primary treatment. The primary end point was treatment effect on intratumoral dihydrotestosterone levels.Results: Intratumoral DHT levels were higher in the degarelix arm than both the degarelix/bicalutamide and LHRH agonist/bicalutamide arms (0.87 ng/g vs. 0.26 ng/g and 0.23 ng/g, P < 0.01). No significant differences existed for other intratumoral androgens, such as testosterone and dehydroepiandrosterone. Patients in the degarelix-only arm had higher AMACR levels on immunohistochemical analysis (P = 0.01). Serum FSH levels were lower after 12 weeks of therapy in both degarelix arms than the LHRH agonist/bicalutamide arm (0.55 and 0.65 vs. 3.65, P < 0.01), and inhibin B levels were lower in the degarelix/bicalutamide arm than the LHRH agonist/bicalutamide arm (82.14 vs. 126.67, P = 0.02).Conclusions: Neoadjuvant degarelix alone, compared with use of LHRH agonist and bicalutamide, is associated with higher levels of intratumoral dihydrotestosterone, despite similar testosterone levels. Further studies that evaluate the mechanisms behind these results are needed. Clin Cancer Res; 23(8); 1974-80. ©2016 AACR.

[Cardiovascular risks with prostate cancer hormonal treatment: rationale for a department of oncocardiology]

Prostate cancer, the most frequent cancer in man, is an adenocarcinoma sensible to chemical castration in more than 80% of cases due to its hormonal dependency. Androgen deprivation is the treatment for advanced cancer and can be associated with radiotherapy locally or in locally advanced situations. Multidisciplinary therapeutic choice depends on patient age and co-morbidities and clinical stage. The impact of hormonal treatment confers varied side effects and cardiovascular effects are now better known. Responsible mechanisms of this cardiotoxicity are at the same time direct but also indirect by metabolic thermogenic effects. Analysis of these clinical or biological effects, their correlations to the used type of hormonal treatment and the possible precautions of prescription will be detailed in this analysis of the literature. The collaboration of the oncologist or the urologist with the cardiologist becomes necessary and the existence of a unit of oncocardiology could improve the evaluation of the risk-benefit balance and the tolerance of the treatment.

[Castration modalities in prostate cancer: Are they all equal?]

AIM

The aim of this literature review was to focus on the new highlights regarding oncologic and safety outcomes depending on the type of castration used.

MATERIAL

Literature search using various algorithms "prostate cancer", "castration", "agonist", "antagonist", "orchiectomy", "GnRH", "FSH", "androgen deprivation therapy" has been performed in April 2015, through the PubMed and Embase databases.

RESULTS

GnRH agonists and antagonists are both currently used in clinical practice. Nevertheless, differences regarding their pharmacologic properties have been highlighted in recent studies, specifically regarding the rapidity, sustainability and depth of the castration, but also the decrease in FSH level. Such differences may have oncological impact on the patient, regarding the disease biological control and the time to progression, and a tolerability impact, especially on the cardiovascular risks. The role of the depth and the sustainability of the castration in one hand, the FSH impact in the other hand, as well as a direct inhibition on extra-pituitary GnRH receptors by antagonist might explain these differences.

CONCLUSIONS

Recent studies suggest differences between GnRH agonists and antagonist that could impact the patient clinical outcomes. However, further high level of evidence comparative studies remains warranted.

Degarelix monotherapy compared with luteinizing hormone-releasing hormone (LHRH) agonists plus anti-androgen flare protection in advanced prostate cancer: an analysis of two randomized controlled trials

OBJECTIVES

The objective of this study was to assess differences in efficacy outcomes between luteinizing hormone-releasing hormone (LHRH) agonist plus antiandrogen (AA) flare protection and monotherapy with the gonadotrophin-releasing hormone antagonist degarelix in patients with prostate cancer.

METHODS

Data from 1455 patients were pooled from two prospective, phase III randomized 1-year clinical trials of degarelix versus LHRH agonist with or without AA. The AA bicalutamide was administered at the investigator's discretion. Adjusted hazard ratios (HRs) were calculated using a Cox proportional hazards regression model and a conditional logistic regression model was used for a case-control analysis of odds ratios (ORs).

RESULTS

Patients received degarelix monotherapy (n = 972) or LHRH agonist (n = 483) of whom 57 also received AA. Overall, prostate-specific antigen progression-free survival (PSA PFS) was improved with degarelix versus LHRH agonist + AA (Cox proportional hazards regression model-adjusted HR for PSA PFS failure was 0.56 [95% confidence interval (CI) 0.33-0.97, p = 0.038]). To compensate for a higher proportion of patients with metastases, Gleason score 7-10, and PSA >20 ng/ml in the LHRH agonist + AA group, a case-control analysis using a conditional logistic regression model was utilized. This resulted in an OR for PSA PFS of 0.42 (95% CI 0.20-0.89; p = 0.023) in the overall population, and 0.35 (95% CI 0.13-0.96; p = 0.042) in patients with PSA >50 ng/ml at baseline, when treated with degarelix versus LHRH agonists + AA. There were a small number of deaths, 1.9% with degarelix and 7% with LHRH agonists + AA (case-control analysis OR = 0.37; p = 0.085).

CONCLUSIONS

Degarelix monotherapy produced a more favorable effect on PSA PFS outcomes than a LHRH agonist + AA flare protection therapy in patients with prostate cancer when a case-control analysis was used to compensate for differences between treatment groups.

Efficacy of degarelix in prostate cancer patients following failure on luteinizing hormone-releasing hormone agonist treatment: results from an open-label, multicentre, uncontrolled, phase II trial (CS27)

OBJECTIVE

To evaluate the efficacy of second-line degarelix in patients with prostate cancer (PCa) after treatment failure with a luteinizing hormone-releasing hormone (LHRH) agonist.

METHODS

This 1-year exploratory, multicentre, open-label phase II trial was performed in 2 patient cohorts (Cohort 1, n = 25; Cohort 2, n = 12) in Germany. Patients with castrate-resistant PCa after primary hormonal treatment received degarelix 240 mg, followed by 11 monthly maintenance doses of 80 mg. The primary endpoint was the proportion of patients with decreasing/stable prostate-specific antigen (PSA) (relative change ⩽+10% of baseline PSA) after 3 months.

RESULTS

At Month 3, the response rate (intention-to-treat, last observation carried forward analysis) was 16.7% [95% confidence interval (CI): 4.74-37.38] in Cohort 1 and 33.3% (95% CI: 9.92-65.11) in Cohort 2. The probability of completing 12 months without PSA progression was 8.8% (95% CI: 1.51-24.3) in Cohort 1 and 8.3% (95% CI: 0.5-31.1) in Cohort 2. Degarelix was well tolerated; the most frequently reported adverse events were local injection-site reactions.

CONCLUSIONS

In PCa patients who failed LHRH therapy, degarelix was well tolerated and achieved a limited PSA response. Phase III trials show that disease control benefits with degarelix versus agonists are more clearly demonstrated as first-line therapy.

Efficacy of treatment with a GnRH antagonist in prostate cancer patients previously treated with a GnRH agonist

PURPOSE

The efficacy of switching from a GnRH agonist to a GnRH antagonist for prostate cancer patients resistant to treatment with the GnRH agonist has not been fully characterized yet. We aimed to evaluate the efficacy of the switch to a GnRH antagonist in patients with PSA failure after hormonal therapy with a GnRH agonist.

METHODS

We retrospectively examined 18 patients with prostate cancer who received androgen-deprivation therapy and who were treated with a GnRH antagonist (degarelix) after they showed an elevated PSA while on GnRH agonist therapy. We evaluated the characteristics of the patients and analyzed some clinical factors for their potential association with the patient response to the switch.

RESULTS

The median PSA at the switch was 7.9 (0.37-1709) ng/ml, and the median testosterone level was 0.17 (<0.08-0.81) ng/ml. Three months after the switch, the median PSA level was 11.3 (0.22-2636) ng/ml, and the median testosterone level was 0.14 (<0.08-0.23) ng/ml. The PSA decreased in six patients (33.3 %) 1 month after the switch, and in three of them it decreased by more than 50 % by 3 months after the switch. Univariate analyses revealed that the lower number of prior treatment lines for prostate cancer before the switch was associated with a favorable decrease in PSA.

CONCLUSIONS

Switching from GnRH agonist to GnRH antagonist therapy was effective for some prostate cancer patients with PSA failure. The small number of prior treatment lines for prostate cancer before the switch was significantly associated with a good PSA response.

Expression of follicle stimulating hormone receptors (FSHR) in thyroid tumours - a marker of malignancy?

BACKGROUND

In normal conditions FSHR are expressed in granulosa cells of the ovary and Sertoli cells of the testis. They can be expressed also in gonadal tumours. However, recently the expression of FSHR was found in tumoral cells and intra-tumoral blood vessels of many other tumours, including thyroid tumours. Aim of this study was to see whether the expression of FSHR can be useful in the differentiation of benign and malignant thyroid lesions.

METHODS

44 samples of surgically excised thyroids were immunostained with anti- FSHR antibody raised against 1-190 amino acid sequence from the human FSHR.

RESULTS

Non-neoplastic thyroid follicles (i.e. the follicles situated outside the tumour) do not show the immunostaining for FSHR. The same concerns the majority of follicular adenomas. In contrast, 87.5% of follicular cancers, the same percentage of papillary cancers and all the examined undifferentiated cancers showed the FSHR immunopositivity of tumoral cells. A tendency towards the higher frequency of FSHR - positive blood vessels also concerns malignant thyroid tumours.

CONCLUSIONS

The ectopic FSHR immunostaining seems to be useful to differentiate malignant from benign lesions, especially follicular cancers from follicular adenomas. However, the further studies on larger material are needed.

Expression and purification of the extracellular domain of the human follicle-stimulating hormone receptor using Escherichia coli

AIM

Although much is known about the structure and biological functions of follicle-stimulating hormone (FSH) receptor (FSHR), the interaction of FSHR and FSH has been challenging to characterize due to the limited quantity of active FSHR protein produced by simple methods. The goal of this study was to express and purify the extracellular domain (ECD) of human FSHR (hFSHR).

METHODS

Total RNA was isolated from normal human ovary tissue. cDNA for hFSHR ECD were amplified and subsequently ligated into the pET32a(+) vector. The plasmid vector construct was confirmed by polymerase chain reaction and sequencing. Expression in Escherichia coli Rosetta (DE3) pLysS strain was induced by isopropyl-thio-β-D-thiogalactoside, and the recombinant products were purified by immuno-affinity chromatography using an Ni-NTA and High-Q column. The recombinant protein was confirmed by western blotting.

RESULTS

Following induction, E. coli expressed a recombinant protein of approximately 65 kDa in size, whereas the non-induced E. coli did not express the recombinant protein. The recombinant fragments purified using a High-Q column demonstrated a single band and an abundant yield. The recombinant protein was soluble and specifically recognized by an antibody for hFSHR. Additionally, four mutation sites were detected that resulted in amino acid shifts at position 112 Asn/Thr, 197 Glu/Ala, 198 Leu/Val and 307 Ala/Thr.

CONCLUSION

The recombinant hFSHR ECD protein was expressed and purified. This method could be easily scaled for increased production and may facilitate additional applications utilizing FSHR in assisted reproductive technology, a contraceptive FSH vaccine and FSHR-targeted therapeutic agents used to treat ovarian cancer.

Serum level of follicle-stimulating hormone is associated with extraprostatic extension of prostate cancer

PURPOSE

To determine whether serum follicle-stimulating hormone (FSH) can be used to predict the aggressiveness of prostate cancer prior to radical prostatectomy.

METHODS

Ninety-six patients who underwent radical prostatectomy for biopsy proved cT1c-T2N0M0 prostate cancer between 2003 and 2008 were identified for retrospective analysis. Using univariate regression analysis, potential variables of extraprostatic tumor extension were identified, including prostate-specific antigen (PSA), luteinizing hormone, FSH, testosterone, biopsy findings, and age. These variables of interest were analyzed by logistic and linear regression analysis to determine if serum FSH is predictive of extraprostatic extension.

RESULTS

Extraprostatic extension was pathologically confirmed in 18 of 96 patients (18.8%). Statistical analysis confirmed that serum FSH was significantly associated with extraprostatic extension (P=0.04). However, age, PSA level, Gleason score, number of tumors, and serum testosterone level were not found to be independent predictors of extraprostatic extension.

CONCLUSIONS

Selective expression of FSH receptor on the surface of blood vessels of prostate cancers has recently been reported. Measuring serum FSH preoperatively in patients with prostate cancer may provide clinically relevant information about extraprostatic spread of tumor.

The hypothalamic-pituitary-gonadal axis and prostate cancer: implications for androgen deprivation therapy

Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) may play important roles in prostate cancer (PCa) progression. Specifically, LH expression in PCa tissues has been associated with metastatic disease with a poor prognosis, while FSH has been shown to stimulate prostate cell growth in hormone-refractory PCa cell lines. Gonadotropin-realizing hormone (GnRH) analogues are common agents used for achieving androgen deprivation in the treatment for PCa. GnRH analogues include LH-releasing hormone (LHRH) agonists and GnRH antagonists, both of which exhibit distinct mechanisms of action that may be crucial in terms of their overall clinical efficacy. LHRH agonists are typically used as the primary therapy for most patients and function via a negative-feedback mechanism. This mechanism involves an initial surge in testosterone levels, which may worsen clinical symptoms of PCa. GnRH antagonists provide rapid and consistent hormonal suppression without the initial surge in testosterone levels associated with LHRH agonists, thus representing an important therapeutic alternative for patients with PCa. The concentrations of testosterone and dihydrotestosterone are significantly reduced after treatment with both LHRH agonists and GnRH antagonists. This reduction in testosterone concentrations to castrate levels results in significant, rapid, and consistent reductions in prostatic-specific antigen, a key biomarker for PCa. Evidence suggests that careful maintenance of testosterone levels during androgen deprivation therapy provides a clinical benefit to patients with PCa, emphasizing the need for constant monitoring of testosterone concentrations throughout the course of therapy.

Serum follicle-stimulating hormone level is associated with human epidermal growth factor receptor type 2 and Ki67 expression in post-menopausal females with breast cancer

The present study aimed to determine the association between levels of the gender hormones, follicle-stimulating hormone (FSH), luteinizing hormone (LH), progesterone (P) and prolactin (PRL), and two breast cancer molecular markers, human epidermal growth factor receptor 2 (Her-2) and Ki67, in post-menopausal patients with breast cancer. A retrospective study of the serum hormone levels of FSH, LH, P and PRL and the expression status of Her-2 and Ki67 was performed using 187 post-menopausal females with breast cancer. Her-2⁺ breast cancer patients exhibited higher serum FSH levels compared with Her-2⁻ patients (69.47±3.219 vs. 58.56±1.516 IU/l). The patients with high Ki67 expression [immunohistochemistry (IHC), 3+] displayed higher FSH (72.51±4.616 vs. 60.53±1.476 IU/l) and LH (32.33±1.916 vs. 26.98±0.8852 IU/l) levels than those with lower Ki67 expression. No correlation was identified between the FSH, LH, P and PRL hormone levels, tumor stages and lymphovascular invasion (LVI). In conclusion, a higher serum FSH level was identified in Her-2⁺ post-menopausal patients with breast cancer. Higher serum FSH and LH levels were also observed in breast cancer patients with high Ki67 expression. FSH and LH may function in the progression of breast cancer.

Follicle stimulating hormone modulates ovarian stem cells through alternately spliced receptor variant FSH-R3

BACKGROUND

We have earlier reported that follicle stimulating hormone (FSH) modulates ovarian stem cells which include pluripotent, very small embryonic-like stem cells (VSELs) and their immediate descendants 'progenitors' termed ovarian germ stem cells (OGSCs), lodged in adult mammalian ovarian surface epithelium (OSE). FSH may exert pleiotropic actions through its alternatively spliced receptor isoforms. Four isoforms of FSH receptors (FSHR) are reported in literature of which FSH-R1 and FSH-R3 have biological activity. Present study was undertaken to identify FSHR isoforms mediating FSH action on ovarian stem cells, using sheep OSE cells culture as the study model.

METHODS

Cultures of sheep OSE cells (a mix of epithelial cells, VSELs, OGSCs and few contaminating red blood cells) were established with and without FSH 5IU/ml treatment. Effect of FSH treatment on self-renewal of VSELs and their differentiation into OGSCs was studied after 15 hrs by qRT-PCR using markers specific for VSELs (Oct-4A, Sox-2) and OGSCs (Oct-4). FSH receptors and its specific transcripts (R1 and R3) were studied after 3 and 15 hrs of FSH treatment by immunolocalization, in situ hybridization and qRT-PCR. FSHR and OCT-4 were also immuno-localized on sheep ovarian sections, in vitro matured follicles and early embryos.

RESULTS

FSH treatment resulted in increased stem cells self-renewal and clonal expansion evident by the appearance of stem cell clusters. FSH receptors were expressed on ovarian stem cells whereas the epithelial cells were distinctly negative. An increase in R3 mRNA transcripts was noted after 3 hrs of FSH treatment and was reduced to basal levels by 15 hrs, whereas R1 transcript expression remained unaffected. Both FSHR and OCT-4 were immuno-localized in nuclei of stem cells, showed nuclear or ooplasmic localization in oocytes of primordial follicles and in cytoplasm of granulosa cells in growing follicles.

CONCLUSIONS

FSH modulates ovarian stem cells via FSH-R3 to undergo potential self-renewal, clonal expansion as 'cysts' and differentiation into oocytes. OCT-4 and FSHR proteins (required initially to maintain pluripotent state of VSELs and for FSH action respectively) gradually shift from nuclei to cytoplasm of developing oocytes and are later possibly removed by surrounding granulosa cells as the oocyte prepares itself for fertilization.

Targeted paclitaxel nanoparticles modified with follicle-stimulating hormone β 81-95 peptide show effective antitumor activity against ovarian carcinoma

The majority of patients with advanced ovarian cancer will experience a relapse and ultimately die from refractory diseases. Targeted therapy shows promise for these patients. Novel therapeutic strategies should be developed on the basis of the molecular mechanisms involved in ovarian cancer and the steroid hormone environment of ovaries. The ovary is the main target organ of follicle-stimulating hormone (FSH), which bind to its receptor with high affinity. In this study a FSH receptor-targeting ligand, FSH β 81-95 peptide, was used as a targeting moiety to synthesize an FSH receptor-mediated drug delivery system. FSH β 81-95 peptide-conjugated nanoparticles (FSH81-NPs) and paclitaxel-loaded FSH81-NPs (FSH81-NP-PTXs) were synthesized. In vitro studies showed that FSH β 81-95 peptide enabled the specific uptake of cytotoxic drugs and increased the intracellular paclitaxel concentration in FSH receptor-expressing cancer cells, resulting in enhanced cytotoxic effects. In vivo studies showed that FSH81-NP-PTXs possessed higher antitumor efficacy against FSH receptor-expressing tumors without any clinical signs of adverse side effects or body weight loss due to modification with FSH β 81-95 peptide. Therefore, FSH binding peptide-targeted drug delivery system exhibited high potential in the treatment of ovarian cancer, and tumor targeting via reproductive hormone receptors might improve the outcome of diseases.

Experience with degarelix in the treatment of prostate cancer

Degarelix is a gonadotrophin-releasing hormone (GnRH) antagonist for the first-line treatment of androgen-dependent advanced prostate cancer. It has a direct mechanism of action that blocks the action of GnRH on the pituitary with no initial surge in gonadotrophin or testosterone levels. Degarelix is the most extensively studied and widely available GnRH antagonist worldwide. Clinical studies have demonstrated similar efficacy to the GnRH agonist leuprolide in achieving testosterone suppression in patients with prostate cancer. However, degarelix produces a faster suppression of testosterone and prostate-specific antigen (PSA), with no testosterone surge or microsurges, thus preventing the risk of clinical flare in advanced disease. Clinical trials have demonstrated that degarelix can offer improved disease control when compared with a GnRH agonist in terms of superior PSA progression-free survival (suggesting that degarelix likely delays progression to castration-resistant disease), and a more significant impact on bone serum alkaline phosphatase and follicle-stimulating hormone. Degarelix is generally well tolerated, with no reports of systemic allergic reactions in any clinical studies. In conclusion, degarelix offers clinicians a rational first-line hormonal monotherapy option for the management of advanced prostate cancer.

Degarelix versus goserelin (+ antiandrogen flare protection) in the relief of lower urinary tract symptoms secondary to prostate cancer: results from a phase IIIb study (NCT00831233)

INTRODUCTION

No studies to date have assessed the efficacy/tolerability of degarelix in the relief of lower urinary tract symptoms (LUTS) secondary to prostate cancer (PrCa).

METHODS

Patients were randomised to degarelix 240/80 mg or goserelin 3.6 mg + bicalutamide flare protection (G+B); both treatments were administered for 3 months. The primary endpoint was change in International Prostate Symptom Score (IPSS) at week 12 compared with baseline.

RESULTS

This study was stopped early due to recruitment difficulties. 40 patients received treatment (degarelix n = 27; G+B n = 13); most had locally advanced disease and were highly symptomatic. Degarelix was non-inferior to G+B in reducing IPSS at week 12 in the full analysis set (p = 0.20); the significantly larger IPSS reduction in the per-protocol analysis (p = 0.04) was suggestive of superior reductions with degarelix. Significantly more degarelix patients had improved quality of life (IPSS question) at week 12 (85 vs. 46%; p = 0.01). Mean prostate size reductions at week 12 were 42 versus 25% for patients receiving degarelix versus G+B, respectively (p = 0.04; post hoc analysis). Most adverse events were mild/moderate; more degarelix patients experienced injection site reactions whereas more G+B patients had urinary tract infections/cystitis.

CONCLUSION

In 40 men with predominantly locally advanced PrCa and highly symptomatic LUTS, degarelix was at least non-inferior to G+B in reducing IPSS at week 12.

Expression of Vascular Endothelial Growth Factor correlates with the advance of clinical osteosarcoma

PURPOSE

Osteosarcoma is the most common primary malignancy in orthopaedic surgery. Studies suggest that expression of VEGF and high vascularity within osteosarcoma may correlate with poor prognosis. The purpose of this study was to determine whether there was a correlation of VEGF expression with clinical tumour stage and metastasis.

METHODS

This retrospective case series examined 54 cases of osteosarcoma patients who were treated during a ten-year period. Relevant clinical information included age, gender, tumour location, stage, adjuvant therapy, morbidity, mortality, and tumour subtypes. The clinical information was analysed for correlation of VEGF expression and tumour prognosis. Tumour sections were examined by routine H&E and by immunohistochemistry for VEGF, CD31, and the oncogenes c-myc and c-fos.

RESULTS

There was a significantly positive correlation between VEGF expression and tumour stages among these cases (p < 0.01). The data also suggested a higher cancer recurrence and more frequent cases of remote metastasis in the high-VEGF group compared to the low-VEGF group. VEGF expression also positively associated with c-fos and c-myc expressions in the primary tumour sections.

CONCLUSION

The results of this study highlight the role of VEGF in angiogenesis and tumour burden. Data also suggest the influence of VEGF may associate with the elevations of c-fos and c-myc expression. The development of novel therapies to target the VEGF pathway in osteosarcoma may lead to improved survival.

New considerations for ADT in advanced prostate cancer and the emerging role of GnRH antagonists

Androgen deprivation therapy (ADT) is first-line treatment for metastatic prostate cancer (PCa). Gonadotrophin-releasing hormone (GnRH) agonists are the most commonly used ADT but have several theoretical physiologic disadvantages (e.g. initial testosterone surge, potential microsurges upon repeat administration). Testosterone surge delays the intended serologic endpoint of testosterone suppression and may exacerbate clinical symptoms. GnRH antagonists were developed with a view toward overcoming these potential adverse physiologic events. This review evaluates GnRH agonists and antagonists, assessing the potential future role of antagonists in PCa and strategies to minimize ADT adverse events (AEs). Evidence was identified via PubMed search (by GnRH agent and other ADT-related terms), from review article bibliographies, and authors' therapy area knowledge, with articles included by author consensus. Degarelix shows similar efficacy to a GnRH agonist in achieving and maintaining castration, with faster onset and without testosterone surge/microsurges. Phase III data showed that, in the first treatment year, degarelix displayed a lower risk of PSA failure or death (composite endpoint), lower levels of the bone marker serum alkaline phosphatase (in baseline metastatic disease), and fewer musculoskeletal AEs than the agonist leuprolide. Also, crossing over from leuprolide to degarelix after 1 year reduced the risk of PSA failure or death. ADT displays an AE spectrum which can impact quality of life as well as causing significant morbidities. Strategies to improve ADT tolerability have become increasingly important including: a holistic management approach, improved diet and exercise, more specific monitoring to detect and prevent testosterone depletion toxicities, and intermittent ADT allowing hormonal recovery between treatment periods. Clinical studies suggest possible benefits of GnRH antagonists over agonists based on different mechanisms of action. GnRH antagonists should now be considered as an alternative first-line ADT option in advanced PCa. Intermittent ADT and a holistic treatment approach are promising strategies to improve ADT tolerability.

The follicle-stimulating hormone receptor: a novel target in genitourinary malignancies

Follicle-stimulating hormone (FSH) is a central hormone in mammalian reproductive biology. The FSH receptor (FSHR), which was previously believed to be expressed primarily in the ovary and testis, was recently found to be expressed in the tumor blood vessels of many solid tumor types, including prostate adenocarcinoma, urothelial carcinoma, and renal cell carcinoma. While the biologic significance of FSHR in tumor blood vessels has yet to be elucidated, FSHR may contribute to neoangiogenesis. FSHR has been reported to be expressed by prostate cancer cells and, thus, targeting FSHR in prostate cancer may be of particular utility. In this report, we discuss the finding of FSHR in tumor blood vessels and review the literature concerning FSHR in genitourinary malignancy. We also discuss the features that make FSHR an appealing target for therapeutic and imaging purposes and the potential utility of FSHR as a prognostic and/or predictive biomarker in genitourinary cancers.

Investigative clinical study on prostate cancer part VI: Follicle-stimulating hormone and the pituitary-testicular-prostate axis at the time of initial diagnosis and subsequent cluster selection of the patient population

AIM

To evaluate the physiopathology of follicle-stimulating hormone (FSH) along the pituitary-testicular-prostate axis at the time of initial diagnosis of prostate cancer in relation to the available clinical variables and to the subsequent cluster selection of the patient population.

PATIENTS AND METHODS

The study included 98 patients who were diagnosed with prostate cancer. Age, percentages of positive cores (P+) at transrectal ultrasound scan biopsy, biopsy Gleason score (bGS), luteinizing hormone (LH), FSH, total testosterone, free testosterone (FT) and prostate-specific antigen (PSA) were the continuous clinical variables. All patients had not previously received hormonal manipulations. FSH correlation and multiple linear analyses were computed in the population. The FSH/PSA ratio was computed and then ranked for clustering the population as groups A (0.13≤FSH/PSA≤0.57), B (0.57<FSH/PSA≤1.61) and C (1.61<FSH/PSA≤19.4). The model was assessed by simple linear and multiple linear regression analysis and differences between the groups were assessed by analysis of variance.

RESULTS

In the patient population, FSH correlated to LH (p < 0.0001), FT (p = 0.007) and age (p = 0.004). FSH was independently predicted by both LH (p < 0.0001) and PSA (p = 0.04). PSA predicted FSH/PSA A (p < 0.0001), B (p < 0.0001) and C (p = 0.04). On multiple regression analysis, FSH/PSA A was predicted by PSA (p < 0.0001), P+ (p = 0.03) and bGS (p = 0.04); FSH/PSA B by LH (p = 0.002) and PSA (p < 0.0001); FSH/PSA C by LH (p < 0.0001) and PSA (p < 0.0001). Moreover, FSH/PSA A, B and C differed for mean values of FSH (p < 0.0001), LH (p < 0.0001), PSA (p < 0.0001) and PSA/FT ratio (p < 0.0001). FSH/PSA clusters showed features of decreasing aggressive disease as the FSH/PSA ratio progressed from A to C.

CONCLUSION

At the diagnosis of prostate cancer and along the pituitary-testis-prostate axis in a patient population FSH significantly correlated to LH, FT and age, and FSH was independently and significantly predicted by both LH and PSA. Because of the independent prediction of PSA by FSH, the prostate cancer population at diagnosis was clustered and ranked according to the FSH/PSA ratio in groups A, B and C. Also, the predictive model of PSA on FSH for the different groups proved to be effective at selecting potential prognostic clusters in which the risk of progression might be assessed as low (group C), intermediate (group B) and high (group A). The FSH/PSA model might be considered as a tool for prostate cancer study and for use in individualized, risk-adapted approaches. However, confirmatory studies are needed.

New treatment paradigm for prostate cancer: abarelix initiation therapy for immediate testosterone suppression followed by a luteinizing hormone-releasing hormone agonist

Study Type - Therapy (prospective cohort). Level of Evidence 2a. What's known on the subject? and What does the study add? The sequential administration of a GnRH antagonist followed by an LHRH agonist in the management of prostate cancer patients has not been studied, but such a program would provide a more physiologic method of achieving testosterone suppression and avoid the obligatory testosterone surge and need for concomitant antiandrogens that accompany LHRH agonist therapy. The current study which uses abarelix initiation therapy for 12 weeks followed by either leuprolide or goserelin demonstrates the ability to more rapidly achieve testosterone suppression, avoid the obligatory LHRH induced testosterone surge, avoid the necessity of antiandrogens, all of which were accomplished safely, without inducing either additional or novel safety issues.

OBJECTIVE

• To demonstrate the safety and endocrinological and biochemical efficacy of initiating treatment with the gonadotropin-releasing hormone (GnRH) antagonist, abarelix, followed by administration of an luteinizing hormone-releasing hormone (LHRH) agonist in patients with advanced and metastatic prostate cancer.

PATIENTS AND METHODS

• A multicentre, open-label design study was conducted at 22 centres in the US involving patients with: localized, locally advanced or metastatic disease; with a rising prostate-specific antigen (PSA) after definitive local treatment; patients undergoing neoadjuvant hormonal therapy before local therapy (radical prostatectomy, radiation therapy or cryosurgery); and patients in whom intermittent therapy was the planned treatment. • All patients received abarelix for 12 weeks followed by an LHRH agonist (either leuprolide or goserelin) for 8 weeks • The primary efficacy endpoint was achievement and maintenance of castration defined as testosterone <50 ng/dL from day 29 through to day 141 and whether abarelix initiation therapy could eliminate the testosterone surge after two consecutive doses of LHRH agonist therapy. • PSA, LH and follicle-stimulating hormone (FSH) levels were measured and adverse events were monitored.

RESULTS

• A total of 176 patients were enrolled into the present study, the majority of whom had localized prostate cancer (82%) and a PSA level <10 ng/mL (62%). • At the end of the abarelix treatment period (day 85), 93.8% of patients achieved castrate levels; during the first week of switch over to the LHRH agonist therapy (days 85-92) the rate was 86.5% and during the week after the second LHRH agonist injection (days 114-12) it was 93.3%. • A small, transient increase in testosterone occurred during the first injection of the LHRH agonist; mean (standard deviation [sd]) values increased from 17 (17.8) ng/dL at day 85 to 37.3 (51.07) ng/dL at day 86. • Mean (sd) PSA levels decreased from 20.5 (56.6) ng/mL at baseline to 3.7 (23.5) ng/mL on day 85 and remained stable throughout the LHRH agonist treatment phase. • Treatment-related adverse events occurred in 84% of patients overall; a similar incidence was reported during the two treatment phases.

CONCLUSIONS

• Abarelix initiation therapy results in the desired effect of achieving rapid testosterone suppression; testosterone surges after subsequent LHRH agonist therapy are greatly abrogated or completely eliminated. • This treatment paradigm (abarelix initiation followed by agonist maintenance) obviates the need for an antiandrogen. • Abarelix was well tolerated and no clinically meaningful or novel adverse events were observed during abarelix treatment or in the transition to LHRH agonist maintenance therapy.

High VEGF with rapid growth and early metastasis in a mouse osteosarcoma model

A murine model of osteosarcoma was developed to investigate the association between the expression of VEGF and the progression of osteosarcoma. Two human osteosarcoma cell lines with distinct VEGF expressions were introduced into proximal tibiae of immuno-deficient SCID mice, either by direct injection through the cortical bone or surgical exposing and drilling on the tibial metaphysis to seed tumor cells. Bone tumors were obvious on microCT within 4 weeks following osteosarcoma cell inoculation through surgical delivery. In contrast, direct injection without drilling often resulted in periosteal tumors. Although neoplasms were developed regardless of VEGF levels, orthotopic tumors derived from high VEGF-expressing cells were detected 2 weeks earlier on CT images than the ones from VEGF negative cells. At sacrifice, high VEGF tumors were distinctively larger in size and more frequently invaded the adjacent bone tissue. Multiple metastatic lesions were found in all the lung tissues at 8 weeks from high VEGF group, whereas only 1 of 7 VEGF negative tumors exhibited pulmonary metastasis. Overall, this model developed with the surgical tumor cell delivery results in histological and radiographic features more consistent with primary osteosarcoma. Interestingly, VEGF expression correlates with the early establishment, rapid tumor growth, and the development of pulmonary metastasis.

[Innovations in hormonal treatment for locally advanced and/or metastatic prostate cancer]

Discovered over 40 years ago, hormonal therapy remains the cornerstone therapy of advanced prostate cancer and continues to evolve. Suppression of serum testosterone remains the mainstay of systemic treatment of prostate cancer. Antagonists of LH-RH are now available and can prevent the castration delay of agonists. They seem to have a clinical benefit in terms of PSA control. During the phase of resistance to extracellular castration, the androgen receptor is the dominant element. Intracellular steroidogenesis can be blocked by Abiraterone. Amplification and mutation of the androgen receptor may be controlled by antiandrogens of second generation. Thus, these new molecules, already or soon available, will renew the strategy of prostate cancer treatment.

Current concepts of follicle-stimulating hormone receptor gene regulation

Follicle-stimulating hormone (FSH), a pituitary glycoprotein hormone, is an integral component of the endocrine axis that regulates gonadal function and fertility. To transmit its signal, FSH must bind to its receptor (FSHR) located on Sertoli cells of the testis and granulosa cells of the ovary. Thus, both the magnitude and the target of hormone response are controlled by mechanisms that determine FSHR levels and cell-specific expression, which are supported by transcription of its gene. The present review examines the status of FSHR/Fshr gene regulation, emphasizing the importance of distal sequences in FSHR/Fshr transcription, new insights gained from the influx of genomics data and bioinformatics, and emerging trends that offer direction in deciphering the FSHR/Fshr regulatory landscape.

Are gonadotrophins tumorigenic--a critical review of clinical and experimental data

The growth of many gonadal and extragonadal tumors is stimulated by gonadal sex hormones. Because gonadal hormone production is regulated by pituitary gonadotrophins, the latter hormones can be considered as indirect tumor promoters. In addition, there is a growing body of evidence that both gonadal (e.g. ovarian cancer) and extragonadal (e.g. breast, uterus, prostate and adrenal) tumors express gonadotrophin receptors, indicating the possibility of a direct tumorigenic role for FSH and LH. The purpose of this brief review is to present a critical evaluation of the current information, both clinical and experimental, about the direct involvement of gonadotrophins in the induction and growth of gonadal and extragonadal tumors.

Expression of follicle-stimulating hormone receptor in tumor blood vessels

BACKGROUND

In adult humans, the follicle-stimulating hormone (FSH) receptor is expressed only in the granulosa cells of the ovary and the Sertoli cells of the testis. It is minimally expressed by the endothelial cells of gonadal blood vessels.

METHODS

We used immunohistochemical and immunoblotting techniques involving four separate FSH-receptor-specific monoclonal antibodies that recognize different FSH receptor epitopes and in situ hybridization to detect FSH receptor in tissue samples from patients with a wide range of tumors. Immunoelectron microscopy was used to detect FSH receptor in mouse tumors.

RESULTS

In all 1336 patients examined, FSH receptor was expressed by endothelial cells in tumors of all grades, including early T1 tumors. The tumors were located in the prostate, breast, colon, pancreas, urinary bladder, kidney, lung, liver, stomach, testis, and ovary. In specimens obtained during surgery performed to remove tumors, the FSH receptor was not expressed in the normal tissues located more than 10 mm from the tumors. The tumor lymphatic vessels did not express FSH receptor. The endothelial cells that expressed FSH receptor were located at the periphery of the tumors in a layer that was approximately 10 mm thick; this layer extended both into and outside of the tumor. Immunoelectron microscopy in mice with xenograft tumors, after perfusion with anti–FSH-receptor antibodies coupled to colloidal gold, showed that the FSH receptor is exposed on the luminal endothelial surface and can bind and internalize circulating ligands.

CONCLUSIONS

FSH receptor is selectively expressed on the surface of the blood vessels of a wide range of tumors. (Funded by INSERM.).

Luteinizing hormone-releasing hormone antagonists

BACKGROUND

Luteinizing hormone-releasing hormone (LH-RH) plays a central role in the vertebrate reproduction by regulating gonadal activity. Based on its binding to pituitary LH-RH receptors, as well as to LH-RH receptors expressed on cancer cells, LH-RH agonists and antagonists have been developed for different therapeutic applications.

OBJECTIVE/METHOD

Here we give an overview of the most relevant LH-RH antagonists and their therapeutic applications. Recently patented compounds as well as drug formulations and dosage are presented.

CONCLUSION

LH-RH antagonists have found clinical applications in in vitro fertilization, benign prostatic hyperplasia, endometriosis and in the treatment of hormone-dependent tumors. Work in progress is focused on further development of both peptidic and orally active non-peptidic LH-RH antagonists.

Activin receptor signaling regulates prostatic epithelial cell adhesion and viability

Mutational changes coupled with endocrine, paracrine, and/or autocrine signals regulate cell division during carcinogenesis. The hormone signals remain undefined, although the absolute requirement in vitro for fetal serum indicates the necessity for a fetal serum factor(s) in cell proliferation. Using prostatic cancer cell (PCC) lines as a model of cancer cell proliferation, we have identified the fetal serum component activin A and its signaling through the activin receptor type II (ActRII), as necessary, although not sufficient, for PCC proliferation. Activin A induced Smad2 phosphorylation and PCC proliferation, but only in the presence of fetal bovine serum (FBS). Conversely, activin A antibodies and inhibin A suppressed FBS-induced PCC proliferation confirming activin A as one of multiple serum components required for PCC proliferation. Basic fibroblast growth factor was subsequently shown to synergize activin A-induced PCC proliferation. Inhibition of ActRII signaling using a blocking antibody or antisense-P decreased mature ActRII expression, Smad2 phosphorylation, and the apparent viability of PCCs and neuroblastoma cells grown in FBS. Suppression of ActRII signaling in PCC and neuroblastoma cells did not induce apoptosis as indicated by the ratio of active/inactive caspase 3 but did correlate with increased cell detachment and ADAM-15 expression, a disintegrin whose expression is strongly correlated with prostatic metastasis. These findings indicate that ActRII signaling is required for PCC and neuroblastoma cell viability, with ActRII mediating cell fate via the regulation of cell adhesion. That ActRII signaling governs both cell viability and cell adhesion has important implications for developing therapeutic strategies to regulate cancer growth and metastasis.

Activation of an olfactory receptor inhibits proliferation of prostate cancer cells

Olfactory receptors (ORs) are expressed not only in the sensory neurons of the olfactory epithelium, where they detect volatile substances, but also in various other tissues where their potential functions are largely unknown. Here, we report the physiological characterization of human OR51E2, also named prostate-specific G-protein-coupled receptor (PSGR) due to its reported up-regulation in prostate cancer. We identified androstenone derivatives as ligands for the recombinant receptor. PSGR can also be activated with the odorant beta-ionone. Activation of the endogenous receptor in prostate cancer cells by the identified ligands evoked an intracellular Ca2+ increase. Exposure to beta-ionone resulted in the activation of members of the MAPK family and inhibition of cell proliferation. Our data give support to the hypothesis that because PSGR signaling could reduce growth of prostate cancer cells, specific receptor ligands might therefore be potential candidates for prostate cancer treatment.