Advances in the design and synthesis of prazosin derivatives over the last ten years

Old drugs, new challenges: reassigning drugs for cancer therapies

The "War on Cancer" began with the National Cancer Act of 1971 and despite more than 50 years of effort and numerous successes, there still remains much more work to be done. The major challenge remains the complexity and intrinsic polygenicity of neoplastic diseases. Furthermore, the safety of the antitumor therapies still remains a concern given their often off-target effects. Although the amount of money invested in research and development required to introduce a novel FDA-approved drug has continuously increased, the likelihood for a new cancer drug's approval remains limited. One interesting alternative approach, however, is the idea of repurposing of old drugs, which is both faster and less costly than developing new drugs. Repurposed drugs have the potential to address the shortage of new drugs with the added benefit that the safety concerns are already established. That being said, their interactions with other new drugs in combination therapies, however, should be tested. In this review, we discuss the history of repurposed drugs, some successes and failures, as well as the multiple challenges and obstacles that need to be addressed in order to enhance repurposed drugs' potential for new cancer therapies.

The Subtype Selectivity in Search of Potent Hypotensive Agents among 5,5-Dimethylhydantoin Derived α1-Adrenoceptors Antagonists

In order to find new hypotensive drugs possessing higher activity and better selectivity, a new series of fifteen 5,5-dimethylhydantoin derivatives (1-15) was designed. Three-step syntheses, consisting of N-alkylations using standard procedures as well as microwaves, were carried out. Crystal structures were determined for compounds 7-9. All of the synthesized 5,5-dimethylhydantoins were tested for their affinity to α1-adrenergic receptors (α1-AR) using both in vitro and in silico methods. Most of them displayed higher affinity (Ki < 127.9 nM) to α1-adrenoceptor than urapidil in radioligand binding assay. Docking to two subtypes of adrenergic receptors, α1A and α1B, was conducted. Selected compounds were tested for their activity towards two α1-AR subtypes. All of them showed intrinsic antagonistic activity. Moreover, for two compounds (1 and 5), which possess o-methoxyphenylpiperazine fragments, strong activity (IC50 < 100 nM) was observed. Some representatives (3 and 5), which contain alkyl linker, proved selectivity towards α1A-AR, while two compounds with 2-hydroxypropyl linker (11 and 13) to α1B-AR. Finally, hypotensive activity was examined in rats. The most active compound (5) proved not only a lower effective dose than urapidil but also a stronger effect than prazosin.

Signaling pathways in vascular function and hypertension: molecular mechanisms and therapeutic interventions

Hypertension is a global public health issue and the leading cause of premature death in humans. Despite more than a century of research, hypertension remains difficult to cure due to its complex mechanisms involving multiple interactive factors and our limited understanding of it. Hypertension is a condition that is named after its clinical features. Vascular function is a factor that affects blood pressure directly, and it is a main strategy for clinically controlling BP to regulate constriction/relaxation function of blood vessels. Vascular elasticity, caliber, and reactivity are all characteristic indicators reflecting vascular function. Blood vessels are composed of three distinct layers, out of which the endothelial cells in intima and the smooth muscle cells in media are the main performers of vascular function. The alterations in signaling pathways in these cells are the key molecular mechanisms underlying vascular dysfunction and hypertension development. In this manuscript, we will comprehensively review the signaling pathways involved in vascular function regulation and hypertension progression, including calcium pathway, NO-NOsGC-cGMP pathway, various vascular remodeling pathways and some important upstream pathways such as renin-angiotensin-aldosterone system, oxidative stress-related signaling pathway, immunity/inflammation pathway, etc. Meanwhile, we will also summarize the treatment methods of hypertension that targets vascular function regulation and discuss the possibility of these signaling pathways being applied to clinical work.

Sustainable Photoinduced Decarboxylative Chlorination Mediated by Halogen Atom Transfer

Chlorinated organic backbones constitute important components in existing biologically active chemicals, and they are extraordinary useful intermediates in organic synthesis. Herein, an operationally simple and sustainable halodecarboxylation protocol via halogen-atom transfer (XAT) as a key step is presented. The method merges a metal-free photoredox system with (diacetoxyiodo)benzene (PIDA) as a hypervalent iodine reagent using 1,2-dihaloethanes as halogen sources to afford haloalkanes in an efficient manner. The sustainability of this protocol is highlighted by an important waste recovery protocol as well as by atom economy and carbon efficiency parameters.

Terazosin Analogs Targeting Pgk1 as Neuroprotective Agents: Design, Synthesis, and Evaluation

Nitrogen-containing heterocyclic compounds have shown promising therapeutic effects in a variety of inflammatory and neurodegenerative diseases. Recently, terazosin (TZ), a heterocyclic compound with a quinazoline core, was found to combine with phosphoglycerol kinase 1 (Pgk1) and protect neurons by enhancing Pgk1 activity and promoting glycolysis, thereby slowing, or preventing the neurodegeneration of PD. These findings indicated that terazosin analogs have bright prospects for the development of PD therapeutics. In this study, a series of terazosin analogs were designed and synthesized for neuroprotective effects by targeting Pgk1. Among them, compound 12b was obtained with the best Pgk1 agonistic activity and neuroprotective activity. Further study indicates that it can increase intracellular ATP content and reduce ROS levels by stimulating the activity of Pgk1, thereby playing a role in protecting nerve cells. In conclusion, this study provides a new strategy and reference for the development of neuroprotective drugs.

Synthesis and Structure-Photophysics Evaluation of 2-N-Amino-quinazolines: Small Molecule Fluorophores for Solution and Solid State

2-N-aminoquinazolines were prepared by consecutive S_N Ar functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morpholino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300-400 nm); whereas the photoluminescence emission maxima (350-450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-π* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe.

Experimental research in rats on the reactivity of new corneal blood vessels to adrenaline

Aim: The purpose of this experimental study was to evaluate the existence of adrenergic receptors in ketamine-induced corneal blood vessels in rat pups. Methods: The study of corneal neovascularization motricity was performed on 45-day-old Wistar rats in which, starting from the 15th day of life, corneal blood vessels were obtained by injecting intraperitoneal ketamine at a dose of 150 mg/ kg body weight, a total of 5 successive doses. The examination of the neovascularization was done with the help of a Nikon stereomicroscope connected to a video camera and a computer, the total magnification being 400X. The reactivity of the new corneal blood vessels to the administration in conjunctival instillations of a 1.5 mmol/L adrenaline solution was tested. The parameters followed were represented by variations in the caliber of corneal blood vessels. The data were analyzed using Microsoft Office Excel. Results: Administration of distilled water did not produce statistically significant changes in corneal blood vessels, while adrenaline produced a statistically significant constriction of vascular diameter (p=0.01 at T9, p=0.004 at T10, p=0.019 at time T11 of examinations). Conclusions: The results showed that adrenaline produces vasoconstriction in the new corneal blood vessels, which allows us to assume that they contain α-adrenergic receptors. However, we cannot say that corneal pathological vessels do not contain β2-type adrenergic receptors, because the effect of adrenaline may be an algebraic sum between vasoconstriction produced by stimulating α-adrenergic receptors and vasodilation produced by stimulating β2-adrenergic receptors, but in which the vasodilating effect may be masked by the vasoconstrictor effect given by a higher density of α-adrenergic receptors. Abbreviations: A= adrenaline, DNM = non-measurable diameter, NA= noradrenaline, Std.Er.= Standard error.

Prescribed drugs containing nitrogen heterocycles: an overview

Heteroatoms as well as heterocyclic scaffolds are frequently present as the common cores in a plethora of active pharmaceuticals natural products. Statistically, more than 85% of all biologically active compounds are heterocycles or comprise a heterocycle and most frequently, nitrogen heterocycles as a backbone in their complex structures. These facts disclose and emphasize the vital role of heterocycles in modern drug design and drug discovery. In this review, we try to present a comprehensive overview of top prescribed drugs containing nitrogen heterocycles, describing their pharmacological properties, medical applications and their selected synthetic pathways. It is worth mentioning that the reported examples are actually limited to current top selling drugs, being or containing N-heterocycles and their synthetic information has been extracted from both scientific journals and the wider patent literature.

First small-molecule PROTACs for G protein-coupled receptors: inducing α 1A-adrenergic receptor degradation

Proteolysis targeting chimeras (PROTACs) are dual-functional hybrid molecules that can selectively recruit an E3 ubiquitin ligase to a target protein to direct the protein into the ubiquitin-proteasome system (UPS), thereby selectively reducing the target protein level by the ubiquitin-proteasome pathway. Nowadays, small-molecule PROTACs are gaining popularity as tools to degrade pathogenic protein. Herein, we present the first small-molecule PROTACs that can induce the α_1A-adrenergic receptor (α_1A-AR) degradation, which is also the first small-molecule PROTACs for G protein-coupled receptors (GPCRs) to our knowledge. These degradation inducers were developed through conjugation of known α₁-adrenergic receptors (α₁-ARs) inhibitor prazosin and cereblon (CRBN) ligand pomalidomide through the different linkers. The representative compound 9c is proved to inhibit the proliferation of PC-3 cells and result in tumor growth regression, which highlighted the potential of our study as a new therapeutic strategy for prostate cancer.

Prazosin inhibits the proliferation, migration and invasion, but promotes the apoptosis of U251 and U87 cells via the PI3K/AKT/mTOR signaling pathway

Prazosin, an α-adrenergic receptor antagonist, is used to treat mild to moderate hypertension. It has recently been discovered that α-adrenergic receptors may have potential antitumor properties. Therefore, in the present study, the effect of prazosin on human glioblastoma and the underlying mechanism were investigated. Human glioblastoma U251 and U87 cells were treated with different concentrations of prazosin, and a Cell Counting Kit-8 assay was performed to investigate the effects of prazosin on cell proliferation. Transwell migration and invasion assays were used to assess the effects of prazosin on cell migration and invasion. Prazosin-induced apoptosis in U251 and U87 cells was detected by flow cytometry, and the protein expression levels of anti-apoptotic proteins and proteins related to the PI3K/AKT/mTOR signaling pathway were detected by western blotting. The results suggested that following treatment with prazosin, the proliferation, migration and invasion of U251 and U81 cells were decreased. By contrast, U251 and U81 cell apoptosis, as well as the protein expression levels of Bax and active Caspase-3 were increased after prazosin treatment (P<0.05). Bcl-2 levels were also decreased after prazosin treatment (P<0.05). Additionally, the expression of phosphorylated (p)-AKT and p-mTOR, P70 and cyclin D1 were decreased in U251 and U81 cells following prazosin treatment (P<0.05). The present study suggested that prazosin may suppress glioblastoma progression by downregulating the activity of the PI3K/AKT/mTOR signaling pathway.

Overcoming cancer therapeutic bottleneck by drug repurposing

Ever present hurdles for the discovery of new drugs for cancer therapy have necessitated the development of the alternative strategy of drug repurposing, the development of old drugs for new therapeutic purposes. This strategy with a cost-effective way offers a rare opportunity for the treatment of human neoplastic disease, facilitating rapid clinical translation. With an increased understanding of the hallmarks of cancer and the development of various data-driven approaches, drug repurposing further promotes the holistic productivity of drug discovery and reasonably focuses on target-defined antineoplastic compounds. The "treasure trove" of non-oncology drugs should not be ignored since they could target not only known but also hitherto unknown vulnerabilities of cancer. Indeed, different from targeted drugs, these old generic drugs, usually used in a multi-target strategy may bring benefit to patients. In this review, aiming to demonstrate the full potential of drug repurposing, we present various promising repurposed non-oncology drugs for clinical cancer management and classify these candidates into their proposed administration for either mono- or drug combination therapy. We also summarize approaches used for drug repurposing and discuss the main barriers to its uptake.

Impact of α-adrenoceptor antagonists on prostate cancer development, progression and prevention

Two decades following the discovery that α1-adrenoceptor antagonists suppress prostate tumor growth at the molecular and cellular level, the impact of α-blockade as re-purposed treatment strategy in the medical management of prostate cancer is gradually being recognized. Prostate cancer is the second most common cause of cancer deaths among males in the United States, yet the disease maintains inconsistent recommendations for prevention and screening. The functional relationship between α-adrenergic signaling and smooth muscle cells in the stroma of the prostate gland and the bladder neck empowered the use of α-adrenoceptor antagonists for the relief of urethral obstruction and clinical symptoms associated with benign prostatic hyperplasia (BPH). Adrenoceptors are G-protein-coupled receptors (GCPRs) that are functionally bound by catecholamines: epinephrine (ER) and norepinephrine (NE). The α1A adrenoceptor subtype is primarily responsible for smooth muscle contraction in the bladder neck and prostate gland. α1-adrenoceptor antagonists are clinically indicated as first-line therapies for the relief of BPH, hypertension, and post-traumatic stress disorder (PTSD). Compelling evidence from cellular and pre-clinical models have identified additional effects of α1-adrenoceptor antagonists regarding their ability to induce apoptosis-mediated suppression of prostate tumor growth and metastasis. Additionally, early epidemiologic data suggest that they may serve as a safe treatment to reduce the risk of prostate cancer. Optimization of quinazoline based compounds (doxazosin) to exploit pharmacologic targeting of tumor growth and vascularization revealed high efficacy of the lead novel compound DZ-50 against prostate tumors. This review discusses the experimental and pre-clinical evidence on the impact of α-blockade on prostate cancer.

The Role of α1-Adrenoceptor Antagonists in the Treatment of Prostate and Other Cancers

This review evaluates the role of α-adrenoceptor antagonists as a potential treatment of prostate cancer (PCa). Cochrane, Google Scholar and Pubmed were accessed to retrieve sixty-two articles for analysis. In vitro studies demonstrate that doxazosin, prazosin and terazosin (quinazoline α-antagonists) induce apoptosis, decrease cell growth, and proliferation in PC-3, LNCaP and DU-145 cell lines. Similarly, the piperazine based naftopidil induced cell cycle arrest and death in LNCaP-E9 cell lines. In contrast, sulphonamide based tamsulosin did not exhibit these effects. In vivo data was consistent with in vitro findings as the quinazoline based α-antagonists prevented angiogenesis and decreased tumour mass in mice models of PCa. Mechanistically the cytotoxic and antitumor effects of the α-antagonists appear largely independent of α 1-blockade. The proposed targets include: VEGF, EGFR, HER2/Neu, caspase 8/3, topoisomerase 1 and other mitochondrial apoptotic inducing factors. These cytotoxic effects could not be evaluated in human studies as prospective trial data is lacking. However, retrospective studies show a decreased incidence of PCa in males exposed to α-antagonists. As human data evaluating the use of α-antagonists as treatments are lacking; well designed, prospective clinical trials are needed to conclusively demonstrate the anticancer properties of quinazoline based α-antagonists in PCa and other cancers.

The anti-hypertensive drug prazosin inhibits glioblastoma growth via the PKCδ-dependent inhibition of the AKT pathway

A variety of drugs targeting monoamine receptors are routinely used in human pharmacology. We assessed the effect of these drugs on the viability of tumor-initiating cells isolated from patients with glioblastoma. Among the drugs targeting monoamine receptors, we identified prazosin, an α1- and α2B-adrenergic receptor antagonist, as the most potent inducer of patient-derived glioblastoma-initiating cell death. Prazosin triggered apoptosis of glioblastoma-initiating cells and of their differentiated progeny, inhibited glioblastoma growth in orthotopic xenografts of patient-derived glioblastoma-initiating cells, and increased survival of glioblastoma-bearing mice. We found that prazosin acted in glioblastoma-initiating cells independently from adrenergic receptors. Its off-target activity occurred via a PKCδ-dependent inhibition of the AKT pathway, which resulted in caspase-3 activation. Blockade of PKCδ activation prevented all molecular changes observed in prazosin-treated glioblastoma-initiating cells, as well as prazosin-induced apoptosis. Based on these data, we conclude that prazosin, an FDA-approved drug for the control of hypertension, inhibits glioblastoma growth through a PKCδ-dependent mechanism. These findings open up promising prospects for the use of prazosin as an adjuvant therapy for glioblastoma patients.

Current perioperative management of pheochromocytomas

Neuroendocrine tumors which have the potential to secrete catecholamines are either associated with sympathetic adrenal (pheochromocytoma) or nonadrenal (paraganglioma) tissue. Surgical removal of these tumors is always indicated to cure and prevent cardiovascular and other organ system complications associated with catecholamine excess. Some of these tumors have malignant potential as well. The diagnosis, localization and anatomical delineation of these tumors involve measurement of catecholamines and their metabolic end products in plasma and urine, ¹²³I-metaiodobenzylguanidine scintigraphy, computed tomography, and/or magnetic resonance imaging. Before surgical removal of the tumors, the optimization of blood pressure, as well as intravascular volume, is an important measure to avoid and suppress perioperative adverse hemodynamic events. Preoperative preparation includes the use of alpha-adrenergic antagonists, beta-adrenergic antagonists with or without other antihypertensive agents, fluid therapy as well as insulin therapy for hyperglycemia if required. Due attention should be given to type and dose of alpha-receptor antagonists to be used and the duration of this therapy to achieve an optimal level of preoperative "alpha-blockade." Despite this preoperative preparation, many patients will have hypertensive crises intraoperatively which need to be promptly and carefully managed by the anesthesia team which requires intensive and advanced monitoring techniques. The most common complication after tumor removal is hypotension which may require fluid therapy and vasopressor support for a few hours. With advancement in surgical and anesthetic techniques, the incidence of severe morbidity and mortality associated with the surgery is low in high volume centers.

The cytotoxicity of the α1-adrenoceptor antagonist prazosin is linked to an endocytotic mechanism equivalent to transport-P

Since the α1-adrenergic antagonist prazosin (PRZ) was introduced into medicine as a treatment for hypertension and benign prostate hyperplasia, several studies have shown that PRZ induces apoptosis in various cell types and interferes with endocytotic trafficking. Because PRZ is also able to induce apoptosis in malignant cells, its cytotoxicity is a focus of interest in cancer research. Besides inducing apoptosis, PRZ was shown to serve as a substrate for an amine uptake mechanism originally discovered in neurones called transport-P. In line with our hypothesis that transport-P is an endocytotic mechanism also present in non-neuronal tissue and linked to the cytotoxicity of PRZ, we tested the uptake of QAPB, a fluorescent derivative of PRZ, in cancer cell lines in the presence of inhibitors of transport-P and endocytosis. Early endosomes and lysosomes were visualised by expression of RAB5-RFP and LAMP1-RFP, respectively; growth and viability of cells in the presence of PRZ and uptake inhibitors were also tested. Cancer cells showed co-localisation of QAPB with RAB5 and LAMP1 positive vesicles as well as tubulation of lysosomes. The uptake of QAPB was sensitive to transport-P inhibitors bafilomycin A1 (inhibits v-ATPase) and the antidepressant desipramine. Endocytosis inhibitors pitstop(®) 2 (general inhibitor of endocytosis), dynasore (dynamin inhibitor) and methyl-β-cyclodextrin (cholesterol chelator) inhibited the uptake of QAPB. Bafilomycin A1 and methyl-β-cyclodextrin but not desipramine were able to preserve growth and viability of cells in the presence of PRZ. In summary, we confirmed the hypothesis that the cellular uptake of QAPB/PRZ represents an endocytotic mechanism equivalent to transport-P. Endocytosis of QAPB/PRZ depends on a proton gradient, dynamin and cholesterol, and results in reorganisation of the LAMP1 positive endolysosomal system. Finally, the link seen between the cellular uptake of PRZ and cell death implies a still unknown pro-apoptotic membrane protein with affinity towards PRZ.

Intratesticular alpha1-adrenergic receptors mediate stress-disturbed transcription of steroidogenic stimulator NUR77 as well as steroidogenic repressors DAX1 and ARR19 in Leydig cells of adult rats

The aim of the present study was to define the role of testicular α1-adrenergic receptors (α1-ADRs) in stress-triggered adaptation of testosterone-producing Leydig cells of adult rats. Results showed that in vivo blockade of testicular α1-ADRs prevented partial recovery of circulating androgen levels registered after 10× repeated immobilization stress (10 × IMO). Moreover, α1-ADR-blockade diminished 10 × IMO-triggered recovery of Leydig cell androgen production, and abolished mitochondrial membrane potential recovery. In the same cells, 10 × IMO-induced increase in Star transcript was abolished, Lhcgr transcript decreased, while transcription of other steroidogenic proteins was not changed. α1-ADR-blockade recovered stress-induced decrease of Nur77, one of the main steroidogenic stimulator, while significantly reduced 10 × IMO-increased in the transcription of the main steroidogenic repressors, Arr19 and Dax1. In vitro experiments revealed an adrenaline-induced α1-ADR-mediated decrease in Nur77 transcription in Leydig cells. Adrenaline-induced increase of repressor Dax1 also involves ADRs in Leydig cells. Accordingly, α1-ADRs participate in some of the stress-triggered effects on the steroidogenic machinery of Leydig cells.

Discovery of Quinazoline-Based Fluorescent Probes to α1-Adrenergic Receptors

α1-Adrenergic receptors (α1-ARs), as the essential members of G protein-coupled receptors (GPCRs), can mediate numerous physiological responses in the sympathetic nervous system. In the current research, a series of quinazoline-based small-molecule fluorescent probes to α1-ARs (1a-1e), including two parts, a pharmacophore for α1-AR recognition and a fluorophore for visualization, were well designed and synthesized. The biological evaluation results displayed that these probes held reasonable fluorescent properties, high affinity, accepted cell toxicity, and excellent subcellular localization imaging potential for α1-ARs.

Emerging therapeutics targeting castration-resistant prostate cancer: the AR-mageddon of tumor epithelial-mesenchymal transition

Advanced prostate cancer will claim nearly 30,000 lives among men in the USA in the year 2013. Most of these will be castration-resistant prostate cancers that are not responsive to traditional therapeutic modalities, and there is no available regimen that fully eradicates metastatic disease. This poses a significant clinical challenge for practitioners and has stimulated the development of novel agents that target these castration-resistant tumor cells. Development of metastatic prostate cancer is orchestrated by multiple signaling pathways that regulate cell survival, apoptosis, anoikis, epithelial-mesenchymal transition (EMT), invasion, the androgen signaling axis and angiogenesis. Disruption of the mechanisms underlying these processes is critical for development of agents that can target otherwise resistant tumor cells. Insights into the mechanisms by which rounds of EMT/mesenchymal-epithelial transition conversions facilitate the progression of localized prostate carcinomas to advanced metastatic and castration-resistant disease emerge as attractive targets for drug development. In this review, the authors discuss the current understanding of therapeutic resistance in castration-resistant prostate cancer with focus on the androgen receptor signaling axis and EMT. Novel therapeutic approaches targeting critical players of both pathways as well as the results from ongoing clinical trials will be discussed in this review.

The opposite roles of glucocorticoid and α1-adrenergic receptors in stress triggered apoptosis of rat Leydig cells

The stress-induced initiation of proapoptotic signaling in Leydig cells is relatively well defined, but the duration of this signaling and the mechanism(s) involved in opposing the stress responses have not been addressed. In this study, immobilization stress (IMO) was applied for 2 h daily, and animals were euthanized immediately after the first (IMO1), second (IMO2), and 10th (IMO10) sessions. In IMO1 and IMO2 rats, serum corticosterone and adrenaline were elevated, whereas serum androgens and mRNA transcription of insulin-like factor-3 in Leydig cells were inhibited. Reduced oxygen consumption and the mitochondrial membrane potential coupled with a leak of cytochrome c from mitochondria and increased caspase-9 expression, caspase-3 activity, and number of apoptotic Leydig cells was also observed. Corticosterone and adrenaline were also elevated in IMO10 rats but were accompanied with a partial recovery of androgen secretion and normalization of insulin-like factor-3 transcription coupled with increased cytochrome c expression, abolition of proapoptotic signaling, and normalization of the apoptotic events. Blockade of intratesticular glucocorticoid receptors diminished proapoptotic effects without affecting antiapoptotic effects, whereas blockade of intratesticular α(1)-adrenergic receptors diminished the antiapoptotic effects without affecting proapoptotic effects. These results confirmed a critical role of glucocorticoids in mitochondria-dependent apoptosis and showed for the first time the relevance of stress-induced upregulation of α(1)-adrenergic receptor expression in cell apoptotic resistance to repetitive IMOs. The opposite role of two hormones in control of the apoptotic rate in Leydig cells also provides a rationale for a partial recovery of androgen production in chronically stressed animals.

Antitumor action of α(1)-adrenoceptor blockers on human bladder, prostate and renal cancer cells

The present study investigated the antitumor action of α(1)-adrenoceptor blockers on human bladder, prostate and renal cancer cells. For bladder cancer cell lines used here such as 253J, 5637, KK-47, T24 and UM-UC-3 cells, prazosin, a selective α(1)-adrenoceptor blocker, reduced cell viability at concentrations more than 30 µmol/l. Likewise, naftopidil, a blocker of α(1A)- and α(1D)-adrenoceptors, reduced cell viability for all the bladder cancer cells used here in a concentration (10-100 µmol/l)-dependent manner, with a much greater advantage than prazosin. Naftopidil also reduced cell viability for human prostate cancer cell lines such as DU145, LNCap and PC-3 cells and ACHN human renal cancer cells, with a much higher potential than prazosin. Thus, the results of the present study suggest that naftopidil could be a beneficial antitumor drug for the treatment of urological cancers.