Dataset Information

The Role of ?1-Adrenoceptor Antagonists in the Treatment of Prostate and Other Cancers.

ABSTRACT: This review evaluates the role of ?-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 ?-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 ?-antagonists prevented angiogenesis and decreased tumour mass in mice models of PCa. Mechanistically the cytotoxic and antitumor effects of the ?-antagonists appear largely independent of ? 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 ?-antagonists. As human data evaluating the use of ?-antagonists as treatments are lacking; well designed, prospective clinical trials are needed to conclusively demonstrate the anticancer properties of quinazoline based ?-antagonists in PCa and other cancers.

SUBMITTER: Batty M

PROVIDER: S-EPMC5000736 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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

Batty Mallory M Pugh Rachel R Rathinam Ilampirai I Simmonds Joshua J Walker Edwin E Forbes Amanda A Anoopkumar-Dukie Shailendra S McDermott Catherine M CM Spencer Briohny B Christie David D Chess-Williams Russ R

International journal of molecular sciences 20160816 8

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 ...[more]

PMID: 27537875

Similar Datasets

Project description:Backgroundα1-Adrenergic receptor antagonists are commonly used to treat benign prostatic hyperplasia. Preclinical studies suggest that they induce cell death and inhibit tumor growth. This study evaluated the risk of prostate cancer death in men using α1-adrenergic receptor antagonists.MethodsA population-based cohort study in Stockholm, Sweden (January 1, 2007, to December 31, 2019) included 451 779 men with a prostate-specific antigen test result. Study entry was 1 year after the first prostate-specific antigen test. Men were considered exposed at their second filled prescription. The primary outcome was prostate cancer mortality. Secondary outcomes were all-cause mortality and prostate cancer incidence. Cox proportional hazards regression models were used to calculate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all outcomes. Inverse-probability weighting with marginal structural models accounted for time-dependent confounders.ResultsOf 351 297 men in the final cohort, 39 856 (11.3%) were exposed to α1-adrenergic receptor antagonists. Median (interquartile range) follow-up for prostate cancer mortality was 8.9 (5.1-10.9) years; median (interquartile range) exposure time to α1-adrenergic receptor antagonists was 4.4 (2.0-7.6) years. There was no evidence of an association between α1-adrenergic receptor antagonist use and prostate cancer mortality, all-cause mortality, or high-grade prostate cancer. α1-Adrenergic receptor antagonist use was associated with an increased risk of prostate cancer (HR = 1.11, 95% CI = 1.06 to 1.17) and low-grade prostate cancer (HR = 1.22, 95% CI = 1.11 to 1.33). Men whose prostate cancer was treated with α1-adrenergic receptor antagonists underwent more frequent prostate-specific antigen testing.ConclusionsOur findings show no significant association between α1-adrenergic receptor adrenoceptor antagonist exposure and prostate cancer mortality or high-grade prostate cancer. Although the preclinical evidence indicates a potential chemopreventive effect, this study's findings do not support it.

Project description:α2-Adrenoceptors, subdivided into α2A, α2B, and α2C subtypes and expressed in heart, blood vessels, kidney, platelets and brain, are important for blood pressure, sedation, analgesia, and platelet aggregation. Brain α2C-adrenoceptor blockade has also been suggested to be beneficial for antipsychotic action. However, comparing α2-adrenoceptor subtype affinity is difficult due to significant species and methodology differences in published studies. Here, 3 H-rauwolscine whole cell binding was used to determine the affinity and selectivity of 99 α-antagonists (including antidepressants and antipsychotics) in CHO cells expressing human α2A, α2B, or α2C-adrenoceptors, using an identical method to β and α1-adrenoceptor measurements, thus allowing direct human receptor comparisons. Yohimbine, RX821002, RS79948, and atipamezole are high affinity non-selective α2-antagonists. BRL44408 was the most α2A-selective antagonist, although its α1A-affinity (81 nM) is only 9-fold greater than its α2C-affinity. MK-912 is the highest-affinity, most α2C-selective antagonist (0.15 nM α2C-affinity) although its α2C-selectivity is only 13-fold greater than at α2A. There are no truely α2B-selective antagonists. A few α-ligands with significant β-affinity were detected, for example, naftopidil where its clinical α1A-affinity is only 3-fold greater than off-target β2-affinity. Antidepressants (except mirtazapine) and first-generation antipsychotics have higher α1A than α2-adrenoceptor affinity but poor β-affinity. Second-generation antipsychotics varied widely in their α2-adrenoceptor affinity. Risperidone (9 nM) and paliperidone (14 nM) have the highest α2C-adrenoceptor affinity however this is only 5-fold selective over α2A, and both have a higher affinity for α1A (2 nM and 4 nM, respectively). So, despite a century of yohimbine use, and decades of α2-subtype studies, there remains plenty of scope to develop α2-subtype selective antagonists.

Project description:Background and purposeParacetamol, a major cause of acute liver failure (ALF) represents a significant clinical problem. Adrenoceptor stimulation or antagonism can modulate chemical-induced hepatotoxicity. We investigated the role of endogenous catecholamines and alpha(1)-adrenoceptors in the development of paracetamol- induced hepatotoxicity.Experimental approachParacetamol (3.5 mmol kg(-1)) was administered to male CD-1 mice, with and without alpha(1)-adrenoceptor antagonists (prazosin, doxazosin, terazosin and tamsulosin; 35.7 micromol kg(-1)). Serum transaminases and hepatic glutathione (GSH) levels were assessed as markers of hepatic damage. Paracetamol bioactivation was assessed by covalent binding, hepatic and urinary conjugate formation and uridine glucuronosyltransferase activity. Plasma catecholamines levels and hepatic congestion were also analysed.Key resultsPlasma catecholamine levels were significantly elevated 5 h post paracetamol administration. Prazosin prevented hepatotoxicity when administered 1 h before a toxic paracetamol insult and importantly, when administered up to 1 h post paracetamol injection. Prazosin had no effect on paracetamol-induced depletion of hepatic GSH, paracetamol bioactivation or paracetamol-induced transcription of defence genes. Paracetamol toxicity is associated with marked accumulation of erythrocytes within hepatic sinusoids and prazosin completely prevented this accumulation.Conclusion and implicationsParacetamol-induced hepatocellular damage is associated with increased circulating catecholamines. alpha(1)-Adrenoceptor antagonists conferred complete protection from paracetamol -induced hepatotoxicity. Protection was associated with absence of hepatic erythrocyte accumulation. Increased catecholamine levels may contribute to the pathophysiology of paracetamol-induced hepatotoxicity by compromising hepatic perfusion. Protection against paracetamol toxicity by alpha(1) antagonists in mice has implications for therapeutic management of patients presenting with paracetamol overdose and ALF.

Project description:Protein kinase C (PKC) plays key roles in the regulation of signal transduction and cellular function in various cell types. At least ten PKC isoforms have been identified and intracellular localization and trafficking of these individual isoforms are important for regulation of enzyme activity and substrate specificity. PKC can be activated downstream of Gq-protein coupled receptor (GqPCR) signaling and translocate to various cellular compartments including plasma membrane (PM). Recent reports suggested that different types of GqPCRs would activate different PKC isoforms (classic, novel and atypical PKCs) with different trafficking patterns. However, the knowledge of isoform-specific activation of PKC by each GqPCR is limited. α1-Adrenoceptor (α1-AR) is one of the GqPCRs highly expressed in the cardiovascular system. In this study, we examined the isoform-specific dynamic translocation of PKC in living HEK293T cells by α1-AR stimulation (α1-ARS). Rat PKCα, βI, βII, δ, ε and ζ fused with GFP at C-term were co-transfected with human α1A-AR into HEK293T cells. The isoform-specific dynamic translocation of PKC in living HEK293T cells by α1-ARS using phenylephrine was measured by confocal microscopy. Before stimulation, GFP-PKCs were localized at cytosolic region. α1-ARS strongly and rapidly translocated a classical PKC (cPKC), PKCα, (<30 s) to PM, with PKCα returning diffusively into the cytosol within 5 min. α1-ARS rapidly translocated other cPKCs, PKCβI and PKCβII, to the PM (<30 s), with sustained membrane localization. One novel PKC (nPKC), PKCε, but not another nPKC, PKCδ, was translocated by α1-AR stimulation to the PM (<30 s) and its membrane localization was also sustained. Finally, α1-AR stimulation did not cause a diacylglycerol-insensitive atypical PKC, PKCζ translocation. Our data suggest that PKCα, β and ε activation may underlie physiological and pathophysiological responses of α1-AR signaling for the phosphorylation of membrane-associated substrates including ion-channel and transporter proteins in the cardiovascular system.

Dataset Information

The Role of ?1-Adrenoceptor Antagonists in the Treatment of Prostate and Other Cancers.

Publications

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

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets