Finasteride effects on hypoxia and angiogenetic markers in benign prostatic hyperplasia

Autophagy in benign prostatic hyperplasia: insights and therapeutic potential

Autophagy is a cellular homeostatic mechanism characterized by cyclic degradation. It plays an essential role in maintaining cellular quality and survival by eliminating dysfunctional cellular components. This process is pivotal in various pathophysiological processes. Benign prostatic hyperplasia (BPH) is a common urological disorder in middle-aged and elderly men. It frequently presents as lower urinary tract symptoms due to an increase in epithelial and stromal cells surrounding the prostatic urethra. The precise pathogenesis of BPH is complex. In recent years, research on autophagy in BPH has gained significant momentum, with accumulating evidence indicating its crucial role in the onset and progression of the disease. This review aims to outline the various roles of autophagy in BPH and elucidate potential therapeutic strategies targeting autophagy for managing BPH.

Hypoxia activates the hypoxia-inducible factor-1α/vascular endothelial growth factor pathway in a prostatic stromal cell line: A mechanism for the pathogenesis of benign prostatic hyperplasia

Background

The development of benign prostatic hyperplasia (BPH) is closely related to hypoxia in the prostatic stroma, and the hypoxia-inducible factor-1α/vascular endothelial growth factor (HIF-1α/VEGF) pathway has been shown to significantly activate in response to hypoxia. The underlying mechanism for activation of this pathway in the pathogenesis of BPH remains unclear.

Materials and methods

We constructed HIF-1α overexpression and knockdown BPH stromal (WPMY-1) and epithelial (BPH-1) cell lines, which were cultured under different oxygen conditions (hypoxia, normoxia, and hypoxia + HIF-1α inhibitor). Quantitative real-time polymerase chain reaction (qPCR) and Western blotting were applied to detect the expression of the HIF-1α/VEGF pathway. Cell proliferation and apoptosis were analyzed by Cell Counting Kit-8 and flow cytometry. We used the miRWalk 2.0 database and Western blotting to predict the potential miRNA that selectively targets the HIF-1α/VEGF pathway, and verified the prediction by qPCR and dual-luciferase assays.

Results

In a BPH stromal cell line (WPMY-1), the expression of VEGF was in accordance with HIF-1α levels, elevated in the overexpression cells and decreased in the knockdown cells. Hypoxia-induced HIF-1α overexpression, which could be reversed by a HIF-1α inhibitor. Moreover, the HIF-1α inhibitor significantly depressed cellular proliferation and promoted apoptosis in hypoxic conditions, assessed by Cell Counting Kit-8 and flow cytometry. However, in the BPH epithelial cell line (BPH-1), the expression level of HIF-1α did not influence the expression of VEGF. Finally, a potential miRNA, miR-17-5p, regulating the HIF-1α/VEGF pathway was predicted from the miRWalk 2.0 database and Western blotting, and verified by qPCR and dual-luciferase assay.

Conclusions

In hypoxia, activation of the HIF-1α/VEGF pathway plays a crucial role in regulating cell proliferation in a BPH stromal cell line. Regulation by miR-17-5p may be the potential mechanism for the activation of this pathway. Regulation of this pathway may be involved in the pathogenesis of BPH.

Evaluating the Impact of Benign Prostatic Hyperplasia Surgical Treatments on Sexual Health

Benign prostatic hyperplasia (BPH), a prevalent condition in older men, is often managed through various surgical interventions. This narrative review aims to explore the impact of these surgical treatments on sexual function, a critical aspect of patient quality of life often overlooked in BPH management. The methodology encompassed a thorough review of contemporary surgical techniques for BPH, including prostate resection, enucleation, vaporization, and minimally invasive therapies such as UroLift, Rezum, and Aquablation. Additionally, the focus was on patient-centered outcomes, with a special emphasis on sexual health following surgery. Findings reveal that, while surgical interventions effectively alleviate BPH symptoms, they often have significant repercussions in sexual function, including erectile and ejaculatory dysfunction. However, emerging techniques demonstrate potential in preserving sexual function, underscoring the need for patient-centric treatment approaches. The study highlights the complex interplay between BPH surgery and sexual health, with minimally invasive treatments showing promise in balancing symptom relief and sexual function preservation. In conclusion, the study advocates for an integrated, interdisciplinary approach to BPH treatment, emphasizing the importance of considering sexual health in therapeutic decision-making. This narrative review suggests a paradigm shift towards minimally invasive techniques could optimize patient outcomes, marrying symptom relief with quality-of-life considerations. The need for further research in this domain is evident, particularly in understanding long-term sexual health outcomes following different surgical interventions for BPH.

Attenuating Adaptive VEGF-A and IL8 Signaling Restores Durable Tumor Control in AR Antagonist-Treated Prostate Cancers

Inhibiting androgen signaling using androgen signaling inhibitors (ASI) remains the primary treatment for castrate-resistant prostate cancer. Acquired resistance to androgen receptor (AR)-targeted therapy represents a major impediment to durable clinical response. Understanding resistance mechanisms, including the role of AR expressed in other cell types within the tumor microenvironment, will extend the clinical benefit of AR-targeted therapy. Here, we show the ASI enzalutamide induces vascular catastrophe and promotes hypoxia and microenvironment adaptation. We characterize treatment-induced hypoxia, and subsequent induction of angiogenesis, as novel mechanisms of relapse to enzalutamide, highlighting the importance of two hypoxia-regulated cytokines in underpinning relapse. We confirmed AR expression in CD34+ vascular endothelium of biopsy tissue and human vascular endothelial cells (HVEC). Enzalutamide attenuated angiogenic tubule formation and induced cytotoxicity in HVECs in vitro, and rapidly induced sustained hypoxia in LNCaP xenografts. Subsequent reoxygenation, following prolonged enzalutamide treatment, was associated with increased tumor vessel density and accelerated tumor growth. Hypoxia increased AR expression and transcriptional activity in prostate cells in vitro. Coinhibition of IL8 and VEGF-A restored tumor response in the presence of enzalutamide, confirming the functional importance of their elevated expression in enzalutamide-resistant models. Moreover, coinhibition of IL8 and VEGF-A resulted in a durable, effective resolution of enzalutamide-sensitive prostate tumors. We conclude that concurrent inhibition of two hypoxia-induced factors, IL8 and VEGF-A, prolongs tumor sensitivity to enzalutamide in preclinical models and may delay the onset of enzalutamide resistance.

IMPLICATIONS

Targeting hypoxia-induced signaling may extend the therapeutic benefit of enzalutamide, providing an improved treatment strategy for patients with resistant disease.

Tissue Kallikrein Protects Rat Prostate against the Inflammatory Damage in a Chronic Autoimmune Prostatitis Model via Restoring Endothelial Function in a Bradykinin Receptor B2-Dependent Way

Objective

The aim of this study was to investigate whether tissue kallikrein (KLK1) can protect the prostate from inflammatory damage and the mechanism involved in it.

Methods

A total of 50 male Wistar rats were used in this study. Initially, 20 rats were sacrificed to obtain the prostate antigen to induce experimental autoimmune prostatitis (EAP), and the remaining 30 rats were randomly divided into 5 experimental groups (normal control group (NC group), NC+KLK1 group (NCK group), EAP group, EAP+KLK1 group (EAPK group), and EAP+KLK1+HOE140 group (EAPKH group); n = 6). It should be explained that KLK1 mainly exerts its biological effects through bradykinin, and HOE140 is a potent and selective bradykinin receptor B2 (BDKRB2) antagonist. EAP was induced by intradermal injection of 15 mg/ml prostate antigen and complete Freund's adjuvant on days 0, 14, and 28. KLK1 was injected via tail vein at a dose of 1.5 × 10⁻³ PAN U/kg once a day, and HOE140 was administered by intraperitoneal injection at 20 μg/kg once every two days. Rats were sacrificed on day 42. The RNA and protein of the rat prostate were extracted to analyze the expression differences of KLK1, as well as the inflammation-, fibrosis-, and oxidative stress-related genes. The inflammatory cell infiltration and microvessel density of the prostate were also analyzed by pathological examination. In addition, pathological analysis was performed on prostate samples from patients undergoing benign prostate hyperplasia (BPH) surgery.

Results

The expression of KLK1 in the prostate decreased in the EAP group as well as BPH patients with obvious inflammation. KLK1 administration significantly inhibited inflammatory cell infiltration and reduced the production of inflammatory cytokines in the EAPK group. Prostate samples from the EAP group showed increased infiltration of T cells and macrophages, as well as gland atrophy, hypoxia, fibrosis, and angiogenesis. KLK1 administration upregulated endothelial nitric oxide synthase (eNOS) expression and suppressed oxidative stress, as well as transforming growth factor β1 (TGF-β) signaling pathways and the proangiogenic vascular endothelial growth factor (VEGF) in the EAPK group. However, in the EAPKH group in which HOE140 blocked BDKRB2, the beneficial effects of KLK1 were all cancelled. In addition, KLK1 intervention in normal rats had no obvious side effects.

Conclusion

The KLK1 expression is inhibited in the inflamed prostates of humans and rats. Exogenous KLK1 restored endothelial function via a BDKRB2-dependent way and then played a role in improving microcirculation and exerted anti-inflammatory, antifibrotic, and antioxidative stress effects in the rat chronic-inflamed prostate.

6-sialyllactose ameliorates dihydrotestosterone-induced benign prostatic hyperplasia through suppressing VEGF-mediated angiogenesis

Benign prostatic hyperplasia (BPH), a common disease in elderly males, is accompanied by non-malignant growth of prostate tissues, subsequently causing hypoxia and angiogenesis. Although VEGF-related angiogenesis is one of the therapeutic targets of prostate cancer, there is no previous study targeting angiogenesis for treatment of BPH. Dihydrotestosterone (DHT)-induced expressions of vascular endothelial growth factor (VEGF) in prostate epithelial RWPE-1 cells and human umbilical vascular endothelial cells (HUVECs). Conditioned media (CM) from DHT-treated RWPE-1 cells were transferred to HUVECs. Then, 6SL inhibited proliferation, VEGFR-2 activation, and tube formation of HUVECs transferred with CM from DHT-treated RWPE-1 cells. In the rat BPH model, 6SL reduced prostate weight, size, and thickness of the prostate tissue. Formation of vessels in prostatic tissues were also reduced with 6SL treatment. We found that 6SL has an ameliorative effect on in vitro and in vivo the BPH model via inhibition of VEGFR-2 activation and subsequent angiogenesis. These results suggest that 6SL might be a candidate for development of novel BPH drugs.

Magnetic Resonance Imaging and Molecular Characterization of a Hormone-Mediated Murine Model of Prostate Enlargement and Bladder Outlet Obstruction

Urinary complications resulting from benign prostatic hyperplasia and bladder outlet obstruction continue to be a serious health problem. Novel animal model systems and imaging approaches are needed to understand the mechanisms of disease initiation, and to develop novel therapies for benign prostatic hyperplasia. Long-term administration of both estradiol and testosterone in mice can result in prostatic enlargement and recapitulate several clinical components of lower urinary tract symptoms. Herein, we use longitudinal magnetic resonance imaging and histological analyses to quantify changes in prostatic volume, urethral volume, and genitourinary vascularization over time in response to estradiol-induced prostatic enlargement. Our data demonstrate significant prostatic enlargement by 12 weeks after treatment, with no detectable immune infiltration by macrophages or T- or B-cell populations. Importantly, the percentage of cell death, as measured by terminal deoxynucleotidyl transferase dUTP nick-end labeling, was significantly decreased in the prostatic epithelium of treated animals as compared to controls. We found no significant change in prostate cell proliferation in treated mice when compared to controls. These studies highlight the utility of magnetic resonance imaging to quantify changes in prostatic and urethral volumes over time. In conjunction with histological analyses, this approach has the high potential to enable mechanistic studies of initiation and progression of clinically relevant lower urinary tract symptoms. In addition, this model is tractable for investigation and testing of therapeutic interventions to ameliorate or potentially reverse prostatic enlargement.

Hypoxia-induced autophagy promotes human prostate stromal cells survival and ER-stress

Benign prostatic hyperplasia (BPH) is emerging as one of the most common diseases seriously threatening the health of elderly men. Accumulating evidences indicate that hypoxia could induce BPH. However, the underlying mechanism of BPH induced by hypoxia is not clear. In the study, hypoxia-induced autophagy could promote cell survival and endoplasmic reticula stress (ER stress) in WPMY-1 cells. Cell viability induced by hypoxia could been decreased by autophagy inhibitors (3-methyladenine, bafilomycin A1) or siRNA interference in two autophagy genes (Beclin1, ATG5) in WPMY-1 cells. Furthermore, ER stress was present in hypoxia-treated WPMY-1 cells, while autophagy and cell survival could been inhibited by C/EBP-homologous protein siRNA (CHOP), which is an important protein of ER stress pathway. Taken together, our data support a novel model that autophagy as a cytoprotective response promotes cell survival via ER stress under hypoxia in human prostate stromal cells.

Impact of preoperative 5α-reductase inhibitors on perioperative blood loss in patients with benign prostatic hyperplasia: a meta-analysis of randomized controlled trials

BACKGROUND

The ability of 5α-reductase inhibitors (5ARIs) to decrease blood loss during transurethral resection of the prostate (TURP) for benign prostatic hyperplasia (BPH) remains controversial. We aimed to conduct a meta-analysis of all randomized controlled trials (RCTs) to establish the role of 5ARI use prior to TURP.

METHODS

We searched studies from the electronic databases PubMed, Embase, Scopus, and Cochrane Library from inception to March 25, 2014. Meta-analysis was performed using the statistical software Review Manager version 5.1.

RESULTS

Seventeen RCTs including 1489 patients were examined. We observed that preoperative treatment with finasteride can decrease total blood loss, blood loss per gram of resected prostate tissue, hemoglobin level alteration, microvessel density (MVD), and vascular endothelial growth factor level. Neither finasteride nor dutasteride reduced operative time, prostate volume, or the weight of gland resected. In contrast, pretreatment with dutasteride before TURP did not decrease the total blood loss or MVD.

CONCLUSIONS

Pretreatment with finasteride does seem to reduce perioperative blood loss related to TURP for BPH patients. However, the effect of preoperative dutasteride was inconclusive. Further studies are required to strengthen future recommendations regarding the use of 5ARI as a standard pre-TURP treatment and its optimal regimen.

Finasteride reduces microvessel density and expression of vascular endothelial growth factor in renal tissue of diabetic rats

BACKGROUND

Vascular endothelial growth factor (VEGF) plays a critical role in the pathogenesis of diabetic microvascular complications. Finasteride has been confirmed to decrease VEGF expression in prostate and prostatic suburethral tissue resulting in limiting hematuria from human benign prostatic hyperplasia. The purpose of this study was to evaluate the effects of finasteride on microvessel density (MVD), VEGF protein and mRNA expressions in the renal tissue of diabetic rats.

METHODS

Diabetic rats induced by streptozotocin were intragastrically given finasteride at 30 mg/kg body weight once a day for 4 weeks. Histomorphologic changes in kidney were observed under light microscope. Immunohistochemistry for CD34 and VEGF on kidney sections was performed to assess MVD and VEGF protein expression in glomeruli of rats, respectively. The VEGF mRNA expression in the renal tissue was examined using reverse transcription polymerase chain reaction analysis.

RESULTS

The glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue were significantly increased in diabetic rats and finasteride-treated rats when compared with controls (P < 0.01, P < 0.05). When compared with diabetic rats, the glomerular tuft area, glomerular volume, MVD, VEGF protein expression in glomeruli and VEGF mRNA expression in the renal cortex tissue of finasteride-treated rats were significantly decreased (P < 0.05, P < 0.01).

CONCLUSIONS

Finasteride reduces the VEGF expression and decreases the MVD in the renal tissue of diabetic rats, suggesting the therapeutic potential of finasteride on diabetic microvascular complications.

PDE5-Is for the Treatment of Concomitant ED and LUTS/BPH

Epidemiologic data in adult men exhibit a strong relationship between erectile dysfunction (ED) and lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH), indicating that men affected by ED should also be investigated for LUTS/BPH and those presenting with storage or voiding LUTS should be investigated for co-morbid ED. Common pathophysiolgical mechanisms underlying both LUTS/BPH and ED, including alteration of NO/cGMP or RhoA/Rho-kinase signaling and/or vascular or neurogenic dysfunction, are potential targets for proposed phosphodiesterase type 5 inhibitors (PDE5-Is). Several randomized controlled trials and only a few reviews including all commercially available PDE5-Is demonstrated the safety and efficacy of these drugs in the improvement of erectile function and urinary symptoms, in patients affected either by ED, LUTS, or both conditions.

A dual 5α-reductase inhibitor dutasteride caused reductions in vascular density and area in benign prostatic hyperplasia

Objectives. Dutasteride, a dual 5α-reductase inhibitor, is used to treat benign prostatic hyperplasia. Nevertheless, its histopathological effects on the morphometrics of blood vessels and glands are still controversial. The aim here was to assess the histopathological effects of dutasteride in cases of benign prostatic hyperplasia in a retrospective study. Methods. Patients with benign prostatic hyperplasia more than 40 cm(3) in prostatic volume were administered 0.5 mg of dutasteride daily or left untreated prior to receiving a transurethral resection of the prostate. Images of sections stained with hematoxylin/eosin and with anti-CD31 antibody were analyzed. Results. In the dutasteride-treated group, the duration of administration was 16.3 ± 8.1 weeks. Artery/arteriole density and vein/venule density in benign prostatic tissue were both lower in the dutasteride-treated group than in the control group. The vein/venule area as a percentage of the whole area was also lower in the dutasteride-treated group, while the artery/arteriole area did not show a significant difference. Glandular/CD31-expressing vessel densities as well as glandular/CD31-expressing vessel areas were comparable between the two groups. Conclusions. Dutasteride reduced the artery/arteriole and vein/venule densities and the proportion of vein/venule area in the tissue of patients with benign prostatic hyperplasia.

A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia

5α-reductase inhibitors (5α-RIs), including finasteride and dutasteride, are commonly used medical therapies for benign prostatic hyperplasia (BPH). Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH, but it was still in controversial. So, we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH. MEDLINE, EMBASE, the Cochrane Controlled Trail Register of Controlled Trials and the reference lists of retrieved studies were searched in the analysis. Sixteen publications involving 15 different randomized controlled trials (RCTs) and a total of 1156 patients were used in the analysis, including 10 RCTs for finasteride and five RCTs for dutasteride. We found that preoperative finasteride treatment decreases microvessel density (MVD) in resected prostate specimens. Total blood loss, blood loss per gram of resected prostate tissue and decreases in haemoglobin were all greatly reduced in the finasteride group as compared to controls. Dutasteride appeared to have no effect on bleeding. This meta-analysis shows that preoperative finasteride treatment could decrease intraoperative haemorrhage during surgery for BPH. Preoperative dutasteride had no effect on intraoperative haemorrhage, but further high-quality prospective studies are still needed to confirm this observation.

Tadalafil for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia: pathophysiology and mechanism(s) of action

BACKGROUND

The PDE5 inhibitor tadalafil is investigation for the treatment of lower urinary tract symptoms (LUTS) in men with benign prostatic hyperplasia (BPH). Several clinical studies of tadalafil and other PDE5 inhibitors have reported significant symptom reduction but limited urinary flow rate improvement. This manuscript reviews the published literature describing the pathophysiology of male LUTS, with an emphasis on mechanisms that may be modulated or improved by phosphodiesterase type 5 (PDE5) inhibition.

METHODS

Literature (through March 2010) was obtained via Medline searches and from the individual reviewers files. Articles were selected for review based on describing in vitro, preclinical, or clinical studies of pathological processes contributing to LUTS, or possible effects of PDE5 inhibition in the lower urinary tract.

RESULTS

Major mechanisms contributing to LUTS include: reduced nitric oxide/cyclic guanosine monophosphate signaling; increased RhoA kinase pathway activity; autonomic overactivity; increased bladder afferent activity; and pelvic ischemia. Tadalafil and other PDE5 inhibitors have demonstrated beneficial effects on smooth muscle relaxation, smooth muscle and endothelial cell proliferation, nerve activity, and tissue perfusion that may impact LUTS in men.

CONCLUSIONS

The pathophysiology of male LUTS is complex and not completely understood. LUTS may occur independently of BPH or secondary to BPH but in both cases involve obstructive or irritative mechanisms with substantial pathophysiological overlap. While the precise mechanism remains unclear, inhibition of PDE5 seems to have an effect on several pathways that may impact LUTS.

Effect of dutasteride on the expression of hypoxia-inducible factor-1alpha, vascular endothelial growth factor and microvessel density in rat and human prostate tissue

OBJECTIVE

To evaluate the effects of dutasteride on the expression of angiogenesis markers in rat and human prostates.

MATERIAL AND METHODS

Eight-week-old male Sprague-Dawley rats were divided into three groups of six each according to dutasteride dose, including the control group (regular diet), 2.5 mg group (2.5 mg/kg dutasteride) and 5.0 mg group (5.0 mg/kg dutasteride). A total of 41 patients awaiting transurethral resection of the prostate (TURP) were divided into two groups: 20 patients received no medication and 21 received 0.5 mg dutasteride daily for 2-4 weeks until TURP.

RESULTS

At 2 weeks, dutasteride effected a significant decrease in body weight and prostate weight compared with the control rat group. Analysis by reverse transcription-polymerase chain reaction and Western blot revealed that hypoxia-inducible factor-1alpha (HIF-1alpha) and vascular endothelial growth factor (VEGF) expression was lower in the dutasteride-treated groups than in the control group, except for HIF-1alpha protein. HIF-1alpha and VEGF expression was similar in the 2.5 mg and 5.0 mg groups. Human prostate tissues demonstrated homogeneous staining of HIF-1alpha and VEGF with regard to extent, intensity and intracellular location in both groups. There was no significant difference in microvessel density between the two groups.

CONCLUSIONS

The expression of HIF-1alpha and VEGF in rat prostates is suppressed by dutasteride. However, less than 4 weeks of dutasteride administration does not suppress the expression of HIF-1alpha, VEGF and microvessel density in human prostate tissue. Further clinical investigation with dutasteride including a larger, placebo-controlled study is warranted to establish the mechanism and duration of dutasteride.

Is hormone therapy a protective factor for late hematuria after high-dose radiotherapy in prostate cancer?

OBJECTIVES

To identify potential clinical and dosimetric factors predictive of a higher risk of grade 2 or higher late hematuria in patients with prostate cancer treated with high-dose radiotherapy.

METHODS

For this purpose, we have analyzed 229 T1c-T3b prostate cancer patients treated with 3-dimensional conformal radiotherapy (3DCRT) in a prospective dose escalation study and with a minimum follow-up of 1 year. The mean radiation dose was 79 Gy (range 72.1 to 84.14 Gy) and the mean follow-up was 47 months (range 14 to 95). One hundred eighteen patients also received androgen deprivation (AD) for high-risk disease. Univariate and multivariate analysis (MVA) were performed to identify variables significantly associated with late hematuria.

RESULTS

Of the 31 (14%) patients with grade 2 or higher genitourinary toxicity, hematuria was the main symptom in 24 (10.5%) with only 1 patient (0.5%) experiencing grade 3 hematuria. On statistical analysis, all the dosimetric parameters failed to show a significant correlation with grade 2 or higher hematuria. On MVA, prior transurethral resection of the prostate (TURP) was significantly associated with a higher risk of late hematuria (relative risk [RR] = 2.8; P = 0.026), whereas long-term AD was correlated with a significantly decreased risk (RR = 0.21; P = 0.019).

CONCLUSIONS

TURP was a relevant factor increasing 3 times the risk of late hematuria in prostate cancer patients treated with 3DCRT. Conversely, long-term AD resulted in a protective factor decreasing 5 times the risk of late hematuria. To our knowledge, this is the first study reporting a protecting effect of long-term hormones in late toxicity after radiotherapy.

The basic biochemistry and molecular events of hormone therapy

Data regarding the molecular response of prostate cancer to hormone therapy continue to emerge, identifying a complex network of autocrine and paracrine signaling events mediating the tumor response to androgen suppression. Emerging data provide insight into cellular pathways important in the apoptotic response to therapy, including the transforming growth factor-beta, insulin-like growth factor-1, and vascular endothelial growth factor signaling axes. They also reveal mechanisms of direct antitumor cytotoxicity mediated by various hormonal agents and highlight the importance of developing antiandrogens capable of irreversibly inhibiting the androgen receptor. Accumulated data emphasize the presence of residual androgens and persistent activation of androgen receptor signaling in advanced prostate tumors despite castration. These factors suggest that a multitargeted treatment approach designed to ablate all contributions to the androgen receptor signaling axis within the prostate tumor microenvironment will be required in order for hormonal therapy to achieve optimal antitumor efficacy.

A rapid, simple, specific liquid chromatographic-electrospray mass spectrometry method for the determination of finasteride in human plasma and its application to pharmacokinetic study

A fast, accurate, sensitive, selective and reliable method using reversed-phase high-performance liquid chromatography-mass spectrometry coupling with an electrospray ionization interface was developed and validated for the determination of finasteride in human plasma. After deprotienation with acetonitrile, centrifugation, evaporation to dryness and dissolving in mobile phase, satisfactory separation was achieved on a Hypersil-Keystone C(18) reversed-phase column using a mobile phase consisting of acetonitrile-water (46:54, v/v), 0.1% acetic acid and 0.1% trifluoracetic acid. Carbamazepine (IS) was used as internal standard. This method involved the use of the [M+H](+) ions of finasteride and IS at m/z 373 and 237 with the selective ion monitoring (SIM) mode. The calibration curve was linear in the range of 0.2-120 ng ml(-1). The limit of quantification for finasteride in plasma was 0.2 ng ml(-1) with good accuracy and precision. The intra-assay precision and accuracy were in the range of 2.1-11.2% and -1.3% to 8.5%, respectively. The inter-assay precision and accuracy were in the order of 3.4-12.1% and -1.5% to 11.5%, respectively. The mean sample extract recoveries of the method were higher than 85% and 74% for finasteride and internal standard (IS), respectively. The assay has been successfully used to estimate the pharmacokinetics of finasteride after oral administration of a 5mg tablet of finasteride to 24 healthy volunteers.