Aromatase inhibition plus/minus Src inhibitor saracatinib (AZD0530) in advanced breast cancer therapy (ARISTACAT): a randomised phase II study.

PURPOSE: The development of oestrogen resistance is a major challenge in managing hormone-sensitive metastatic breast cancer. Saracatinib (AZD0530), an oral Src kinase inhibitor, prevents oestrogen resistance in animal models and reduces osteoclast activity. We aimed to evaluate the efficacy of saracatinib addition to aromatase inhibitors (AI) in patients with hormone receptor-positive metastatic breast cancer. METHODS: This phase II multicentre double-blinded randomised trial allocated post-menopausal women to AI with either saracatinib or placebo (1:1 ratio). Patients were stratified into an "AI-sensitive/naïve" group who received anastrozole and "prior-AI" group who received exemestane. Primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR) and toxicity. RESULTS: 140 patients were randomised from 20 UK centres to saracatinib/AI (n = 69) or placebo/AI (n = 71). Saracatinib was not associated with an improved PFS (3.7 months v. 5.6 months placebo/AI) and did not reduce likelihood of bony progression. There was no benefit in OS or ORR. Effects were consistent in "AI-sensitive/naive" and "prior-AI" sub-groups. Saracatinib was well tolerated with dose reductions in 16% and the main side effects were gastrointestinal, hypophosphatemia and rash. CONCLUSION: Saracatinib did not improve outcomes in post-menopausal women with metastatic breast cancer. There was no observed beneficial effect on bone metastases. CRUKE/11/023, ISRCTN23804370.

One Size Does Not Fit All in Remote Anatomy Teaching.

Anatomical knowledge is central to the advancement of biomedical research and clinical practice and provides the underpinning foundations for many clinical examinations and processes. Anatomy is a very practical and three-dimensional subject, requiring learners to be able to visualise structures within the body and how they interact with each other. Typically, this is taught through a combination of lectures and practical laboratories in which students can interact with human cadaveric material to gain an appreciation of real-life anatomy, often commenting on how these lab sessions really bring their lectures to life.Like so many things, the teaching of anatomy on university campuses became severely restricted with the arrival of the COVID-19 pandemic in March 2020. Staff and students were no longer able to attend universities and body donation programmes were halted. This brought with it both challenges and opportunities to redevelop digital anatomy education. This chapter will discuss the different teaching approaches taken to delivery anatomy education at the University of Glasgow in three different programmes: (1) Bachelor of Science Honours (BSc Hons) degree in Anatomy, (2) the Glasgow Access to Medicine Programme (GAP), and (3) the undergraduate Bachelor degree in Medicine (MBChB). These three programmes were selected as they each teach anatomy to undergraduate students but the teaching methods, class sizes, and student backgrounds for each is very different. In discussing the different approaches taken and reflecting on staff and student feedback on these experiences, we hope to provide not just a record of the unprecedented and rapid changes to education during this time but also to offer some thoughts on how lessons might be learned as we return to on-campus teaching.

A Phase II study of neoadjuvant axitinib for reducing the extent of venous tumour thrombus in clear cell renal cell cancer with venous invasion (NAXIVA).

BACKGROUND: Surgery for renal cell carcinoma (RCC) with venous tumour thrombus (VTT) extension into the renal vein (RV) and/or inferior vena cava (IVC) has high peri-surgical morbidity/mortality. NAXIVA assessed the response of VTT to axitinib, a potent tyrosine kinase inhibitor. METHODS: NAXIVA was a single-arm, multi-centre, Phase 2 study. In total, 20 patients with resectable clear cell RCC and VTT received upto 8 weeks of pre-surgical axitinib. The primary endpoint was percentage of evaluable patients with VTT improvement by Mayo level on MRI. Secondary endpoints were percentage change in surgical approach and VTT length, response rate (RECISTv1.1) and surgical morbidity. RESULTS: In all, 35% (7/20) patients with VTT had a reduction in Mayo level with axitinib: 37.5% (6/16) with IVC VTT and 25% (1/4) with RV-only VTT. No patients had an increase in Mayo level. In total, 75% (15/20) of patients had a reduction in VTT length. Overall, 41.2% (7/17) of patients who underwent surgery had less invasive surgery than originally planned. Non-responders exhibited lower baseline microvessel density (CD31), higher Ki67 and exhausted or regulatory T-cell phenotype. CONCLUSIONS: NAXIVA provides the first Level II evidence that axitinib downstages VTT in a significant proportion of patients leading to reduction in the extent of surgery. CLINICAL TRIAL REGISTRATION: NCT03494816.

Lifestyle coaching is feasible in fatigued brain tumor patients: A phase I/feasibility, multi-center, mixed-methods randomized controlled trial.

Background: There are no effective treatments for brain tumor-related fatigue. We studied the feasibility of two novel lifestyle coaching interventions in fatigued brain tumor patients. Methods: This phase I/feasibility multi-center RCT recruited patients with a clinically stable primary brain tumor and significant fatigue (mean Brief Fatigue Inventory [BFI] score ≥ 4/10). Participants were randomized in a 1-1-1 allocation ratio to: Control (usual care); Health Coaching ("HC", an eight-week program targeting lifestyle behaviors); or HC plus Activation Coaching ("HC + AC", further targeting self-efficacy). The primary outcome was feasibility of recruitment and retention. Secondary outcomes were intervention acceptability, which was evaluated via qualitative interview, and safety. Exploratory quantitative outcomes were measured at baseline (T0), post-interventions (T1, 10 weeks), and endpoint (T2, 16 weeks). Results: n = 46 fatigued brain tumor patients (T0 BFI mean = 6.8/10) were recruited and 34 were retained to endpoint, establishing feasibility. Engagement with interventions was sustained over time. Qualitative interviews (n = 21) suggested that coaching interventions were broadly acceptable, although mediated by participant outlook and prior lifestyle. Coaching led to significant improvements in fatigue (improvement in BFI versus control at T1: HC=2.2 points [95% CI 0.6, 3.8], HC + AC = 1.8 [0.1, 3.4], Cohen's d [HC] = 1.9; improvement in FACIT-Fatigue: HC = 4.8 points [-3.7, 13.3]; HC + AC = 12 [3.5, 20.5], d [HC and AC] = 0.9). Coaching also improved depressive and mental health outcomes. Modeling suggested a potential limiting effect of higher baseline depressive symptoms. Conclusions: Lifestyle coaching interventions are feasible to deliver to fatigued brain tumor patients. They were manageable, acceptable, and safe, with preliminary evidence of benefit on fatigue and mental health outcomes. Larger trials of efficacy are justified.

Effect of androgen treatment during foetal and/or neonatal life on ovarian function in prepubertal and adult rats.

We investigated the effects of different windows of testosterone propionate (TP) treatment during foetal and neonatal life in female rats to determine whether and when excess androgen exposure would cause disruption of adult reproductive function. Animals were killed prepubertally at d25 and as adults at d90. Plasma samples were taken for hormone analysis and ovaries serial sectioned for morphometric analyses. In prepubertal animals, only foetal+postnatal and late postnatal TP resulted in increased body weights, and an increase in transitory, but reduced antral follicle numbers without affecting total follicle populations. Treatment with TP during both foetal+postnatal life resulted in the development of streak ovaries with activated follicles containing oocytes that only progressed to a small antral (smA) stage and inactive uteri. TP exposure during foetal or late postnatal life had no effect upon adult reproductive function or the total follicle population, although there was a reduction in the primordial follicle pool. In contrast, TP treatment during full postnatal life (d1-25) resulted in anovulation in adults (d90). These animals were heavier, had a greater ovarian stromal compartment, no differences in follicle thecal cell area, but reduced numbers of anti-Mullerian hormone-positive smA follicles when compared with controls. Significantly reduced uterine weights lead reduced follicle oestradiol production. These results support the concept that androgen programming of adult female reproductive function occurs only during specific time windows in foetal and neonatal life with implications for the development of polycystic ovary syndrome in women.

Identification in rats of a programming window for reproductive tract masculinization, disruption of which leads to hypospadias and cryptorchidism.

Becoming a phenotypic male is ultimately determined by androgen-induced masculinization. Disorders of fetal masculinization, resulting in hypospadias or cryptorchidism, are common, but their cause remains unclear. Together with the adult-onset disorders low sperm count and testicular cancer, they can constitute a testicular dysgenesis syndrome (TDS). Although masculinization is well studied, no unifying concept explains normal male reproductive development and its abnormalities, including TDS. We exposed rat fetuses to either anti-androgens or androgens and showed that masculinization of all reproductive tract tissues was programmed by androgen action during a common fetal programming window. This preceded morphological differentiation, when androgen action was, surprisingly, unnecessary. Only within the programming window did blocking androgen action induce hypospadias and cryptorchidism and altered penile length in male rats, all of which correlated with anogenital distance (AGD). Androgen-driven masculinization of females was also confined to the same programming window. This work has identified in rats a common programming window in which androgen action is essential for normal reproductive tract masculinization and has highlighted that measuring AGD in neonatal humans could provide a noninvasive method to predict neonatal and adult reproductive disorders. Based on the timings in rats, we believe the programming window in humans is likely to be 8-14 weeks of gestation.

Androgen action via testicular peritubular myoid cells is essential for male fertility.

Androgens are essential for normal spermatogenesis and male fertility, but how androgens exert this effect remains uncertain. Androgen receptors (ARs) are expressed in several testicular cell types, but continuing uncertainty exists over which cell type mediates androgen control of spermatogenesis. Androgen signaling via Sertoli cells (SCs) is essential for complete spermatogenesis, but the role for androgen signaling via peritubular myoid (PTM) cells is contentious. To address this controversy, we generated PTM-specific AR-knockout (PTM-ARKO) mice in which gross reproductive development was normal, but all PTM-ARKO males were azoospermic and infertile. Testis weight was reduced beyond puberty, and in adulthood there was an 86% reduction in germ cells, compared with wild-type littermates. These changes were not explained by any deficits in testosterone, luteinizing hormone, or follicle-stimulating hormone concentrations. SC function was impaired in PTM-ARKO males, indicated by reduced seminiferous tubule fluid production and reduced expression of some androgen-dependent SC genes. Androgen action via PTM cells is therefore essential for normal testis function, spermatogenesis, and fertility in males. This study also provides the first direct evidence for the importance of androgen-driven stromal-epithelial interactions underpinning the regulation of spermatogenesis; PTM-ARKO mice will enable identification of the new molecular pathways involved.

Critical androgen-sensitive periods of rat penis and clitoris development.

Androgen control of penis development/growth is unclear. In rats, androgen action in a foetal 'masculinisation programming window' (MPW; e15.5-e18.5)' predetermines penile length and hypospadias occurrence. This has implications for humans (e.g. micropenis). Our studies aimed to establish in rats when androgen action/administration affects development/growth of the penis and if deficits in MPW androgen action were rescuable postnatally. Thus, pregnant rats were treated with flutamide during the MPW +/- postnatal testosterone propionate (TP) treatment. To assess penile growth responsiveness, rats were treated with TP in various time windows (late foetal, neonatal through early puberty, puberty onset, or combinations thereof). Phallus length, weight, and morphology, hypospadias and anogenital distance (AGD) were measured in mid-puberty (d25) or adulthood (d90) in males and females, plus serum testosterone in adult males. MPW flutamide exposure reduced adult penile length and induced hypospadias dose-dependently; this was not rescued by postnatal TP treatment. In normal rats, foetal (e14.5-e21.5) TP exposure did not affect male penis size but increased female clitoral size. In males, TP exposure from postnatal d1-24 or at puberty (d15-24), increased penile length at d25, but not ultimately in adulthood. Foetal + postnatal TP (e14-postnatal d24) increased penile size at d25 but reduced it at d90 (due to reduced endogenous testosterone). In females, this treatment caused the biggest increase in adult clitoral size but, unlike in males, phallus size was unaffected by TP during puberty (d15-24). Postnatal TP treatment advanced penile histology at d25 to more resemble adult histology. AGD strongly correlated with final penis length. It is concluded that adult penile size depends critically on androgen action during the MPW but subsequent growth depends on later androgen exposure. Foetal and/or postnatal TP exposure does not increase adult penile size above its 'predetermined' length though its growth towards this maximum is advanced by peripubertal TP treatment.

Human HSD17B1 expression masculinizes transgenic female mice.

When present in excess amounts during fetal life, androgens can impair female development by inducing masculinization. On way to modify fetal steroid concentration is by altering the expression of hydroxysteroid (17beta) dehydrogenases (HSD17Bs). Human HSD17B1 converts weak estrogen estrone to estradiol, and with lower catalytic efficiency, weak androgen androstenedione to testosterone. We have recently shown that over-expression of human HSD17B1 in transgenic mice results in masculinized phenotype in female mice. In the present study, we further show that in addition to the Müllerian ducts, HSD17B1TG females have internal structures resembling Wolffian ducts, and enlarged Skene paraurethral gland, also called the female prostate. HSD17B1 expression has been found in fetal human ovary, thus, it is possible that HSD17B1 contributes to maintain the normal steroid hormone concentration during development. Thereby, abnormal increase in the fetal expression of HSD17B1 could contribute to the development of hormonal imbalances, and so result in female masculinization.

Activation of androgens by hydroxysteroid (17beta) dehydrogenase 1 in vivo as a cause of prenatal masculinization and ovarian benign serous cystadenomas.

Hydroxysteroid (17beta) dehydrogenases (HSD17Bs) belong to the short-chain dehydrogenase/reductase family consisting of a diverse pool of enzymes with oxidoreductase activity. HSD17B enzymes catalyze the conversion between 17-keto and 17-hydroxy steroids, either activating or inactivating sex steroids. Previous studies have demonstrated a role for human HSD17B1 enzyme in estradiol (E2) biosynthesis both in gonads and extragonadal steroid target tissues and various estrogen-dependent diseases. In the present study, five transgenic (TG) mouse lines universally overexpressing human HSD17B1 were generated and characterized at fetal and adult ages, especially to study the enzyme function in vivo. Activity measurements in vivo indicated that in addition to activating estrone to E2, the enzyme is able to significantly reduce androstenedione to testosterone, and TG females presented increased testosterone concentration preceding birth. As a consequence, TG females suffered from several phenotypic features typical to enhanced fetal androgen exposure. Furthermore, the ovaries developed androgen-dependent ovarian benign serous cystadenomas at adulthood. Androgen dependency of the phenotypes was confirmed by rescuing them by antiandrogen treatment, or by transplanting wild-type ovaries to the TG females. In conclusion, the data evidently show that, in addition to activating estrone to E2, human HSD17B1 enhances androgen action in vivo. Thus, the relative amounts of androgenic and estrogenic substrates available partially determine the physiological function of the enzyme in vivo. The novel function observed for human HSD17B1 is likely to open new possibilities also for the use of HSD17B1-inhibitors as drugs against androgen-related dysfunctions in females.

The critical time window for androgen-dependent development of the Wolffian duct in the rat.

Androgens are thought to separately regulate stabilization and differentiation of the Wolffian duct (WD), but the time windows for these effects are unclear. To address this, fetal rats were exposed to flutamide within either an early window (EW) [embryonic day 15.5 (E15.5) to E17.5], when the WD degenerates in the female, or a later window (LW) (E19.5-E21.5), when the WD morphologically differentiates in the male, or during the full window of WD development (FW) (E15.5-21.5). WDs were examined for abnormalities during fetal (E21.5) or postnatal life, and anogenital distance and prostate presence/absence were recorded. Exposure to FW- or EW-flutamide, but not to LW-flutamide, induced comparable abnormalities in the fetal WD at E21.5, namely reduced WD coiling, reduced cell proliferation, reduced epithelial cell height, altered epithelial vimentin expression, and reduced expression of smooth muscle actin in the WD inner stroma. Exposure to EW- or FW-flutamide, but not to LW-flutamide, resulted in incomplete/absent WDs in more than 50% of males by adulthood, although such abnormalities were infrequent in fetal life. These findings suggest that androgen action during the EW is sufficient to promote WD morphological differentiation several days later. Because the androgen receptor is expressed in the WD stroma but not in the epithelium during this EW, WD differentiation is likely to be dependent on androgen-mediated signaling from the stroma to the epithelium. In conclusion, the critical window for androgen action in regulating WD development in the rat is between E15.5 and E17.5. This window is also important for prostate formation and anogenital distance masculinization.

Role of androgens in fetal testis development and dysgenesis.

This study sought to establish whether reduced androgen levels/action in the fetal rat testis induced by di(n-butyl) phthalate (DBP) contributes to dysgenetic features, namely reduced Sertoli cell number, occurrence of multinucleated gonocytes (MNG), and Leydig cell aggregation. Pregnant rats were administered treatments or cotreatments designed to manipulate testosterone levels [DBP, testosterone propionate (TP)] or action [flutamide, 7,12-dimethyl-benz[a]anthracene (DMBA)]. The aforementioned end points were analyzed and related to intratesticular testosterone (ITT) levels and peripheral androgen action (anogenital distance). Dysgenetic features were also evaluated in mice with inactivation of the androgen receptor (testicular feminized or ARKO mice). Exposure to DBP alone, or combined with flutamide, DMBA, or TP, resulted in reduced Sertoli cell number and ITT levels, as did exposure to TP alone; coadministration of DBP + TP caused the most severe reduction in both parameters. A positive correlation between ITT levels and Sertoli cell number was found (r = 0.791; P = 0.019). Similarly, exposure to DBP alone, or as a cotreatment, significantly increased occurrence of MNG and Leydig cell aggregation, and these were negatively correlated with ITT levels. Exposure to flutamide or DMBA alone had no significant effect on these dysgenetic end points. These findings suggest that reduced ITT decreases fetal Sertoli cell numbers and might be involved in Leydig cell aggregation and MNG. However, of these three end points, only Sertoli cell number was affected significantly in ARKO/testicular feminized mice with absent androgen action. Therefore, induction of MNG and Leydig cell aggregation might result from DBP-induced effects other than suppression of ITT levels.

Increased T-cell Infiltration Elicited by Erk5 Deletion in a Pten-Deficient Mouse Model of Prostate Carcinogenesis.

Prostate cancer does not appear to respond to immune checkpoint therapies where T-cell infiltration may be a key limiting factor. Here, we report evidence that ablating the growth regulatory kinase Erk5 can increase T-cell infiltration in an established Pten-deficient mouse model of human prostate cancer. Mice that were doubly mutant in prostate tissue for Pten and Erk5 (prostate DKO) exhibited a markedly increased median survival with reduced tumor size and proliferation compared with control Pten-mutant mice, the latter of which exhibited increased Erk5 mRNA expression. A comparative transcriptomic analysis revealed upregulation in prostate DKO mice of the chemokines Ccl5 and Cxcl10, two potent chemoattractants for T lymphocytes. Consistent with this effect, we observed a relative increase in a predominantly CD4+ T-cell infiltrate in the prostate epithelial and stroma of tumors from DKO mice. Collectively, our results offer a preclinical proof of concept for ERK5 as a target to enhance T-cell infiltrates in prostate cancer, with possible implications for leveraging immune therapy in this disease. Cancer Res; 77(12); 3158-68. ©2017 AACR.

Analysis of Nkx3.1:Cre-driven Erk5 deletion reveals a profound spinal deformity which is linked to increased osteoclast activity.

Extracellular signal-regulated protein kinase 5 (ERK5) has been implicated during development and carcinogenesis. Nkx3.1-mediated Cre expression is a useful strategy to genetically manipulate the mouse prostate. While grossly normal at birth, we observed an unexpected phenotype of spinal protrusion in Nkx3.1:Cre;Erk5 fl/fl (Erk5 fl/fl) mice by ~6-8 weeks of age. X-ray, histological and micro CT (µCT) analyses showed that 100% of male and female Erk5 fl/fl mice had a severely deformed curved thoracic spine, with an associated loss of trabecular bone volume. Although sex-specific differences were observed, histomorphometry measurements revealed that both bone resorption and bone formation parameters were increased in male Erk5 fl/fl mice compared to wild type (WT) littermates. Osteopenia occurs where the rate of bone resorption exceeds that of bone formation, so we investigated the role of the osteoclast compartment. We found that treatment of RANKL-stimulated primary bone marrow-derived macrophage (BMDM) cultures with small molecule ERK5 pathway inhibitors increased osteoclast numbers. Furthermore, osteoclast numbers and expression of osteoclast marker genes were increased in parallel with reduced Erk5 expression in cultures generated from Erk5 fl/fl mice compared to WT mice. Collectively, these results reveal a novel role for Erk5 during bone maturation and homeostasis in vivo.

Androgen-dependent mechanisms of Wolffian duct development and their perturbation by flutamide.

Androgens play a vital role in Wolffian duct (WD) development, but the mechanisms that underlie this are unknown. The present study used in utero exposure of pregnant rats to the androgen receptor antagonist flutamide (50 or 100 mg/kg) to explore possible mechanisms. Pregnant rats were treated from embryonic d 15.5 (E15.5), and WDs were isolated from fetuses from E17.5-E21.5 and from adults. WD morphology was evaluated, and total length of the duct lumen was determined in fetal samples. Fetal WDs were immunostained for androgen receptor and stromal (inner and outer) and/or epithelial-cell-specific markers and analyzed for cell proliferation and apoptosis. In adulthood, most flutamide-exposed males lacked proximal WD-derived tissues, whereas at E18.5-E19.5, a time when the WD has completely regressed in females, a complete normal WD was present in all flutamide-exposed animals. This suggests that flutamide, at doses of 50 or 100 mg/kg, interferes with WD differentiation, not stabilization. Consistent with this, WD elongation/coiling increased in controls by 204% between E19.5 and E21.5 but increased less significantly (103%) in flutamide-exposed animals. This was associated with reduced cell proliferation, but there was no increase in apoptosis or change in expression of androgen receptor mRNA or protein. Flutamide treatment impaired differentiation of inner stromal cells, shown by decreased expression of smooth muscle actin, before effects were noted in the epithelium, consistent with androgens driving WD development via stromal-epithelial interactions. In conclusion, WD differentiation is far more susceptible to blockade of androgen action than is its initial stabilization, and these effects may be mediated by disruption of stromal-epithelial interactions.

The masculinization programming window.

Sexual differentiation is a tightly regulated series of events which transform the indifferent gonads and genitalia into sex-specific structures. This is driven by hormones produced by the fetal testes, primarily testosterone (T). However, masculinization of each structure does not occur synchronously and, until recently, it was presumed that androgens also control this masculinization over a broad period of fetal life, coincident with the period of fetal T production. However, a common fetal masculinization programming window (MPW) has been identified in male and female rodent models in which androgens must act to masculinize all components of the reproductive tract and allow their later complete development. Impaired androgen action only within this MPW can induce cryptorchidism and hypospadias. This MPW is likely to occur between 8-14 weeks' gestation in humans. Studies in transgenic mice have begun to investigate some of the underlying mechanisms involved. Anogenital distance is predictive of the incidence of disorders, such as azoospermia, hypospadias and cryptorchidism, and could provide a noninvasive, lifelong indicator of androgen action within this MPW, useful in clinical assessment of patients with disorders of sexual development. In addition, several diagnostic characteristics of the external genitalia are also useful in investigating this MPW.

Androgen receptor expression in the caput epididymal epithelium is essential for development of the initial segment and epididymal spermatozoa transit.

The epididymis plays an essential role in male fertility, and disruption of epididymal function can lead to obstructive azoospermia. Formation and function of the epididymis is androgen-dependent. The androgen receptor (AR) is expressed in both the stromal and epithelial compartments of the epididymis, and androgen action mediated via stromal cells is vital for its normal development and function. However the impact of epithelial specific AR-dependent signaling in the epididymis remains underexplored. To address this, we used conditional gene-targeting in mice to selectively ablate AR from the caput epididymal epithelium, and characterized the resulting phenotype at multiple postnatal ages. Caput epithelium androgen receptor knock-out mice have normal serum testosterone concentrations at day (d) 21 and d100, but do not develop an epididymal initial segment. The remaining caput epithelium displays a significant decrease in epithelial cell height from d11 and lumen diameter from d21 and disruption of the smooth muscle layer of the caput epididymis at d100. From d21, caput epithelium androgen receptor knock-out mice accumulate cell debris, proteinaceous material, and, at later ages, spermatozoa in their efferent ducts, which prevents normal passage of spermatozoa from the testis into the cauda epididymis resulting in infertility when tested at d100. This efferent duct obstruction leads to fluid back-pressure and disruption of the seminiferous epithelium of the adult testis. We conclude that epithelial AR signaling is essential for postnatal development and function of the epididymal epithelium and that disruption of this signaling can contribute to obstructive azoospermia.

Smooth muscle cell-specific knockout of androgen receptor: a new model for prostatic disease.

Androgen-driven stromal-epithelial interactions play a key role in normal prostate development and function as well as in the progression of common prostatic diseases such as benign prostatic hyperplasia and prostate cancer. However, exactly how, and via which cell type, androgens mediate their effects in the adult prostate remains unclear. This study investigated the role for smooth muscle (SM) androgen signaling in normal adult prostate homeostasis and function using mice in which androgen receptor was selectively ablated from prostatic SM cells. In adulthood the knockout (KO) mice displayed a 44% reduction in prostate weight and exhibited histological abnormalities such as hyperplasia, inflammation, fibrosis, and reduced expression of epithelial, SM, and stem cell identify markers (e.g. p63 reduced by 27% and Pten by 31%). These changes emerged beyond puberty and were not explained by changes in serum hormones. Furthermore, in response to exogenous estradiol, adult KO mice displayed an 8.5-fold greater increase in prostate weight than controls and developed urinary retention. KO mice also demonstrated a reduced response to castration compared with controls. Together these results demonstrate that prostate SM cells are vital in mediating androgen-driven stromal-epithelial interactions in adult mouse prostates, determining cell identity and function and limiting hormone-dependent epithelial cell proliferation. This novel mouse model provides new insight into the possible role for SM androgen action in prostate disease.

Androgen action via testicular arteriole smooth muscle cells is important for Leydig cell function, vasomotion and testicular fluid dynamics.

Regulation of blood flow through the testicular microvasculature by vasomotion is thought to be important for normal testis function as it regulates interstitial fluid (IF) dynamics which is an important intra-testicular transport medium. Androgens control vasomotion, but how they exert these effects remains unclear. One possibility is by signalling via androgen receptors (AR) expressed in testicular arteriole smooth muscle cells. To investigate this and determine the overall importance of this mechanism in testis function, we generated a blood vessel smooth muscle cell-specific AR knockout mouse (SMARKO). Gross reproductive development was normal in SMARKO mice but testis weight was reduced in adulthood compared to control littermates; this reduction was not due to any changes in germ cell volume or to deficits in testosterone, LH or FSH concentrations and did not cause infertility. However, seminiferous tubule lumen volume was reduced in adult SMARKO males while interstitial volume was increased, perhaps indicating altered fluid dynamics; this was associated with compensated Leydig cell failure. Vasomotion was impaired in adult SMARKO males, though overall testis blood flow was normal and there was an increase in the overall blood vessel volume per testis in adult SMARKOs. In conclusion, these results indicate that ablating arteriole smooth muscle AR does not grossly alter spermatogenesis or affect male fertility but does subtly impair Leydig cell function and testicular fluid exchange, possibly by locally regulating microvascular blood flow within the testis.

Deletion of androgen receptor in the smooth muscle of the seminal vesicles impairs secretory function and alters its responsiveness to exogenous testosterone and estradiol.

The seminal vesicles (SVs), like much of the male reproductive tract, depend on androgen-driven stromal-epithelial interactions for normal development, structure, and function. The primary function of the SVs is to synthesize proteins that contribute to the seminal plasma and this is androgen dependent. However, the cell-specific role for androgen action in adult SVs remains unclear. This study analyzed the SV in mice with targeted ablation of androgen receptors specifically in smooth muscle cells (PTM-ARKO) to determine in vivo whether it is androgen action in a subset of the SV stroma, the smooth muscle cells, that drives epithelial function and identity. These mice have significantly smaller SVs in adulthood with less smooth muscle and reduced epithelial cell height. Less epithelial cell proliferation was observed in adult PTM-ARKO SVs, compared with controls, and production of seminal proteins was reduced, indicating global impairment of epithelial cell function in PTM-ARKO SVs. None of these changes could be explained by altered serum testosterone or estradiol concentrations. We also demonstrate altered SV responsiveness to exogenous testosterone and estradiol in PTM-ARKO mice, indicating that smooth muscle androgen receptors may limit the SV epithelial proliferative response to exogenous estrogens. These results therefore demonstrate that the smooth muscle cells play a vital role in androgen-driven stromal-epithelial interactions in the SV, determining epithelial cell structure and function as well as limiting the SV epithelial proliferative response to exogenous estrogens.