Nonselective Β-adrenergic Receptor Antagonist Research Articles

The Arrhythmogenicity of Sotalol and its Role in Heart Failure: A Literature Review.

According to the American Heart Association (AHA), approximately six million adults have been afflicted with heart failure (HF) in the United States in 2020 and are more likely to have sudden cardiac death accounting for approximately 50% of the cause of mortality. Sotalol is a nonselective β-adrenergic receptor antagonist with class III antiarrhythmic properties that has been mostly utilized for atrial fibrillation treatment and suppressing recurrent ventricular tachyarrhythmias. The use of sotalol in patients with left ventricular (LV) dysfunction is not recommended by the American College of Cardiology (ACC) or AHA as studies are inconclusive with conflicting results regarding safety. This article aims to review the mechanism of action of sotalol, the β-blocking effects on heart failure, and provide an overview of clinical trials on sotalol use and its effects in patients with heart failure. Small and large scale clinical trials have been controversial and inconclusive about the use of sotalol in heart failure. Sotalol has been shown to reduce defibrillation energy requirements and reduce shocks from implantable cardioverter-defibrillators. TdP is the most life-threatening arrhythmia that has been documented with sotalol use and occurs more commonly in women and HF patients. Thus far, mortality benefits have not been demonstrated with sotalol use and larger multicenter studies are required going forward.

Glucagon-Like Peptide-1 Is Involved in the Thermic Effects of Dietary Proteins in Male Rodents.

Protein intake potently increases body temperature and energy expenditure, but the underlying mechanism thereof remains incompletely understood. Simultaneously, protein intake potently stimulates glucagon-like peptide-1 (GLP-1) secretion. Here, we examined the involvement of GLP-1 in the thermic effects of dietary proteins in rodents by measuring rectal temperature and energy expenditure and modulating GLP-1 signaling. Rectal temperature of rats or mice fasted for 4 or 5 hours were measured using a thermocouple thermometer before and after an oral administration of nutrients. Oxygen consumption after oral protein administration was also measured in rats. Rectal temperature measurements in rats confirmed an increase in core body temperature after refeeding, and the thermic effect of the oral administration of protein was greater than that of a representative carbohydrate or lipid. Among the five dietary proteins examined (casein, whey, rice, egg, and soy), soy protein had the highest thermic effect. The thermic effect of soy protein was also demonstrated by increased oxygen consumption. Studies using a nonselective β-adrenergic receptor antagonist and thermal camera suggested that brown adipose tissue did not contribute to soy protein-induced increase in rectal temperature. Furthermore, the thermic effect of soy protein was completely abolished by antagonism and knockout of the GLP-1 receptor, yet potentiated via augmentation of intact GLP-1 levels through inhibition of dipeptidyl peptidase-4 activity. These results indicate that GLP-1 signaling is essential for the thermic effects of dietary proteins in rats and mice, and extend the metabolic actions of GLP-1 ensuing from nutrient ingestion to encompass the thermic response to ingested protein.

Is Infantile Hemangioma a Neuroendocrine Tumor?

Infantile hemangioma (IH) is the most common infantile tumor, affecting 5–10% of newborns. Propranolol, a nonselective β-adrenergic receptor (ADRB) antagonist, is currently the first-line treatment for severe IH; however, both its mechanism of action and its main cellular target remain poorly understood. Since betablockers can antagonize the effect of natural ADRB agonists, we postulated that the catecholamine produced in situ in IH may have a role in the propranolol response. By quantifying catecholamines in the IH tissues, we found a higher amount of noradrenaline (NA) in untreated proliferative IHs than in involuted IHs or propranolol-treated IHs. We further found that the first three enzymes of the catecholamine biosynthesis pathway are expressed by IH cells and that their levels are reduced in propranolol-treated tumors. To study the role of NA in the pathophysiology of IH and its response to propranolol, we performed an in vitro angiogenesis assay in which IH-derived endothelial cells, pericytes and/or telocytes were incorporated. The results showed that the total tube formation is sensitive to propranolol only when exogenous NA is added in the three-cell model. We conclude that the IH’s sensitivity to propranolol depends on crosstalk between the endothelial cells, pericytes and telocytes in the context of a high local amount of local NA.

Cyclosporin-A reduced the cytotoxicity of propranolol in HUVECs via p38 MAPK signaling.

Propranolol (PROP) is a nonselective β-adrenergic receptor antagonist used to treat hypertension and cardiac arrhythmias. Oral administration of PROP has recently emerged as a new treatment modality for hemangiomas. However, the side effects of PROP at the cellular level have not been adequately described.The present study investigates and highlights the mechanisms of coupling of the drugs cyclosporin-A (CyA) and PROP on cell proliferation and the occurrence of apoptosis. It also relays the antioxidant effect of PROP on human umbilical vein endothelial cells (HUVECs).HUVECs were treated with CyA and PROP. At 24 hours after treatment, the levels of reactive oxygen species (ROS), cell proliferation, and apoptosis were determined using the ROS kit, MTT assay, and Annexin V staining. In addition, the related proteins of phospho-p38 mitogen-activated protein kinase were determined by western blotting. Subsequently, HUVECs pretreated with CyA or PROP were treated with the p38 inhibitor (SB203580). Finally, the ROS level, cell proliferation, and apoptosis were measured again in both active HUVECs and HUVECs, in which the p38 proteins were inhibited.The combination of CyA and PROP reversed the effect of CyA on cell viability, reduced the ROS level and the cell apoptosis induced by PROP. Moreover, inhibition of p38 protein catalase activity immediately stopped the effect of CyA–propranolol in HUVECs.The effect of the CyA–propranolol combination on HUVECs is associated with the p38 pathway changes, which is proven to be a potential chemotherapeutic agent that minimizes the side effects of PROP in hemangioma therapy.

Activation of the β-adrenergic receptor exacerbates lipopolysaccharide-induced wasting of skeletal muscle cells by increasing interleukin-6 production

The skeletal muscle mass has been shown to be affected by catecholamines, such as epinephrine (Epi), norepinephrine (NE), and isoproterenol (ISO). On the other hand, lipopolysaccharide (LPS), one of the causative substances of sepsis, induces muscle wasting via toll-like receptors expressed in skeletal muscle. Although catecholamines are frequently administered to critically ill patients, it is still incompletely understood how these drugs affect skeletal muscle during critical illness, including sepsis. Herein, we examined the direct effects of catecholamines on LPS-induced skeletal muscle wasting using the C2C12 myoblast cell line. Muscle wasting induced by catecholamines and/or LPS was analyzed by the use of the differentiated C2C12 myotubes, and its underlying mechanism was explored by immunoblotting analysis, quantitative reverse transcription polymerase chain reaction (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), and the TransAM kit for p-65 NF-κB. Epi augmented myosin heavy chain (MHC) protein loss and reduction of the myotube diameter induced by LPS. LPS induced C/EBPδ protein, Atrogin-1 and inteleukin-6 (IL-6), and these responses were potentiated by Epi. An IL-6 inhibitor, LMT28, suppressed the potentiating effect of Epi on the LPS-induced responses. NF-κB activity was induced by LPS, but was not affected by Epi and recombinant IL-6, and the NF-κB inhibitor, Bay 11-7082, abolished Atrogin-1 mRNA expression induced by LPS with or without Epi. NE and ISO also potentiated LPS-induced IL-6 and Atroign-1 mRNA expression. Carvedilol, a nonselective β-adrenergic receptor antagonist, suppressed the facilitating effects of Epi on the Atrogin-1 mRNA induction by LPS, and abolished the effects of Epi on the MHC protein loss in the presence of LPS. It was concluded that Epi activates the β-adrenergic receptors in C2C12 myotubes and the IL-6-STAT3 pathway, leading to the augmentation of LPS-induced activation of the NF-κB- C/EBPδ-Atrogin-1 pathway and to the exacerbation of myotube wasting.

Propranolol Therapy in Infantile Hemangioma: It Is Not Just About the Beta.

Propranolol, a nonselective β-adrenergic receptor antagonist, is approved by the U.S. Food and Drug Administration to treat problematic infantile hemangiomas, but a subset of patients experience treatment complications. Parents wary of long-term use and side effects consult plastic surgeons on surgical options or as a second opinion. Understanding the mechanism(s) of action of propranolol will allow plastic surgeons to better inform parents. A systemic literature search was performed to query published translational and basic science studies on propranolol effects on infantile hemangiomas and cells derived from these lesions. In experimental studies, propranolol was antiproliferative and cytotoxic against hemangioma endothelial and stem cells and affected infantile hemangioma perivascular cell contractility. Propranolol inhibited migration, network formation, vascular endothelial growth factor A production, and vascular endothelial growth factor receptor 2 activation and down-regulated PI3K/AKT and mitogen-activated protein kinase signaling in hemangioma endothelial cells, but it increased ERK1/2 activity in hemangioma stem cells. At effective clinical doses, measured propranolol plasma concentration is 100 times higher than necessary for complete β-adrenergic receptor blockade, yet was 10 to 100 times less than required to induce hemangioma stem cell death. Propranolol targets multiple cell types in infantile hemangiomas by means of β-adrenergic receptor-dependent and -independent mechanisms. Plasma concentration played a significant role. At clinically relevant doses, incomplete infantile hemangioma suppression may explain the rebound phenomenon and worsening ulceration, and propranolol off target effects may lead to commonly reported adverse effects, such as sleep and gastrointestinal disturbances. Propranolol limitations and complications underscore the importance of surgical treatment options in cases of rebound and severe adverse effects. Surgical intervention remains an important treatment choice when parents are hesitant to use propranolol.

Critical role of Aquaporin-1 and telocytes in infantile hemangioma response to propranolol beta blockade

Propranolol, a nonselective β-adrenergic receptor (ADRB) antagonist, is the first-line therapy for severe infantile hemangiomas (IH). Since the incidental discovery of propranolol efficacy in IH, preclinical and clinical investigations have shown evidence of adjuvant propranolol response in some malignant tumors. However, the mechanism for propranolol antitumor effect is still largely unknown, owing to the absence of a tumor model responsive to propranolol at nontoxic concentrations. Immunodeficient mice engrafted with different human tumor cell lines were treated with anti-VEGF bevacizumab to create a model sensitive to propranolol. Proteomics analysis was used to reveal propranolol-mediated protein alteration correlating with tumor growth inhibition, and Aquaporin-1 (AQP1), a water channel modulated in tumor cell migration and invasion, was identified. IH tissues and cells were then functionally investigated. Our functional protein association networks analysis and knockdown of ADRB2 and AQP1 indicated that propranolol treatment and AQP1 down-regulation trigger the same pathway, suggesting that AQP1 is a major driver of beta-blocker antitumor response. Examining AQP1 in human hemangioma samples, we found it exclusively in a perivascular layer, so far unrecognized in IH, made of telocytes (TCs). Functional in vitro studies showed that AQP1-positive TCs play a critical role in IH response to propranolol and that modulation of AQP1 in IH-TC by propranolol or shAQP1 decreases capillary-like tube formation in a Matrigel-based angiogenesis assay. We conclude that IH sensitivity to propranolol may rely, at least in part, on a cross talk between lesional vascular cells and stromal TCs.

COMT Genotype and Efficacy of Propranolol for TMD Pain: A Randomized Trial

Propranolol is a nonselective β-adrenergic receptor antagonist that is efficacious in reducing facial pain. There is evidence that its analgesic efficacy might be modified by variants of the catechol-O-methyltransferase (COMT) gene. We tested the hypothesis in a subset of 143 non-Hispanic Whites from a randomized controlled trial of patients with painful temporomandibular disorder (TMD). Patients were genotyped for rs4680, a single nucleotide polymorphism of COMT, and randomly allocated to either propranolol 60 mg twice daily or placebo. During the 9-wk follow-up period, patients recorded daily ratings of facial pain intensity and duration; the product was computed as an index of facial pain. Postbaseline change in the index at week 9 (the primary endpoint) was analyzed as a continuous variable and dichotomized at thresholds of ≥30% and ≥50% reduction. Mixed models for repeated measures tested for the genotype × treatment group interaction and estimated means, odds ratios (ORs), and 95% confidence limits (95% CLs) of efficacy within COMT genotypes assuming an additive genetic model. In secondary analysis, the cumulative response curves were plotted for dichotomized reductions ranging from ≥20% to ≥70%, and genotype differences in area under the curve percentages (%AUC) were calculated to signify efficacy. Mean index reduction did not differ significantly (P = 0.277) according to genotype, whereas the dichotomized ≥30% reduction revealed greater efficacy among G:G homozygotes (OR = 10.9, 95%CL = 2.4, 50.7) than among A:A homozygotes (OR = 0.8, 95%CL = 0.2, 3.2) with statistically significant interaction (P = 0.035). Cumulative response curves confirmed greater (P = 0.003) efficacy for G:G homozygotes (%AUC difference = 43.7, 95%CL = 15.4, 72.1) than for A:A homozygotes (%AUC difference = 6.5, 95%CL = -30.2, 43.2). The observed antagonistic effect of the A allele on propranolol’s efficacy was opposite the synergistic effect hypothesized a priori. This unexpected result highlights the need for better knowledge of COMT’s role in pain pathogenesis if the gene is to be used for precision-medicine treatment of TMD (ClinicalTrials.gov NCT02437383).

Abstract 3062: Drug repurposing of β-blocker propranolol and hemostatic compound desmopressin in osteosarcoma: Preclinical antitumor activity on 2D and 3D cell growth, chemotaxis and xenograft progression

Abstract Introduction. Osteosarcoma (OS) is the most common malignant primary bone tumor in children and young adults, with alarmingly elevated mortality rates, especially in developing countries. OS patients bear highly invasive and vascularized tumors, with limited response to standard of care (SoC) therapies, and are in urgent need of novel therapeutic strategies. Propranolol (PPN) is a non-selective β-adrenergic receptor (β-AR) antagonist originally used in the treatment of diverse heart diseases. On the other hand, desmopressin (dDAVP) is a hemostatic drug that acts as a selective agonist for the vasopressin type-2 receptor (AVPR2) present in blood microvessels and several tumor types. Given that β-ARs and AVPR2 signalling regulates many cellular processes involved in the initiation and progression of cancer, multiple efforts have been made to repurpose PPN and dDAVP in indications such as breast and colorectal cancer, melanoma and angiosarcoma, among others. Considering the unsatisfied clinical needs of OS, the objective of this work was to evaluate the in vitro/in vivo antitumoral activity of PPN and dDAVP on highly aggressive preclinical models of OS. Materials and methods. The human OS cell lines MG-63 and U2-OS were used for in vitro or in vivo experiments. Target expression was assessed by qPCR and immunohistochemistry. Sensitivity to PPN or dDAVP was evaluated by in vitro 72 h proliferation, 7 d clonogenic growth, 3D spheroid formation, transwell chemotaxis assays and MG-63 xenograft progression in nude mice. In addition, PPN was evaluated as monotherapy or in combination with SoC chemotherapy. Results. PPN (10-100 µM) and dDAVP (0.1-10 µM) drastically reduced clonogenic and 3D growth, migration, mitotic index and proliferation of β-AR and AVPR2-expressing OS cells (p<0.05). Synergistic antitumoral effects were observed after combining PPN with cisplatin or methotrexate, in vitro and in vivo (CI<1). In animals bearing growing OS s.c. xenografts sustained treatment during 4 weeks with PPN (10 mg/kg i.p. daily) or dDAVP (12 µg/kg i.v. three times a week) markedly abrogated tumor progression, exhibiting modulation of local tumor aggressiveness and reducing final tumor burden by 25 or 45%, respectively (p<0.01). Conclusions. Taking into account PPN and dDAVP robust antitumoral effects, β-ARs antagonization or agonist activation of AVPR2 are achievable and interesting therapeutic approaches to modulate OS tumor aggressiveness. Both agents could be proposed as coadyuvant agents for treating OS, not only in combination with chemotherapy but also administered during the perioperative setting. Citation Format: Luisina Solerno, Natasha Sobol, Rocío Rodriguez, Marina Pifano, Giselle Ripoll, Hernan Farina, Liliana Vasquez, Daniel F. Alonso, Juan Garona. Drug repurposing of β-blocker propranolol and hemostatic compound desmopressin in osteosarcoma: Preclinical antitumor activity on 2D and 3D cell growth, chemotaxis and xenograft progression [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3062.

Thromboxane A2 in the paraventricular hypothalamic nucleus mediates glucoprivation-induced adrenomedullary outflow

Glucoprivation stimulates a rapid sympathetic response to release and/or secrete catecholamines into the bloodstream. However, the central regulatory mechanisms involving adrenoceptors and prostanoids production in the paraventricular hypothalamic nucleus (PVN) that are responsible for the glucoprivation-induced elevation of plasma catecholamines are still unresolved. In this study, we aimed to clarify whether glucoprivation-induced activation of noradrenergic neurons projecting to the PVN can induce α- and/or β-adrenergic receptor activation and prostanoids production in the PVN to elevate plasma catecholamine levels. We examined the effects of α- and β-adrenergic receptor antagonists, a cyclooxygenase inhibitor, a thromboxane A synthase inhibitor, and a PGE2 subtype EP3 receptor antagonist on intravenously administered 2-deoxy-D-glucose (2-DG)-induced elevation of noradrenaline in the PVN and plasma levels of catecholamine in freely moving rats. In addition, we examined whether intravenously administered 2-DG can increase prostanoids levels in the PVN microdialysates. Intracerebroventricular (i.c.v.) pretreatment with phentolamine (a non-selective α-adrenergic receptor antagonist) suppressed the 2-DG-induced increase in the plasma level of adrenaline, whereas i.c.v. pretreatment with propranolol (a non-selective β-adrenergic receptor antagonist) suppressed the 2-DG-induced elevation of the plasma level of noradrenaline. I.c.v. pretreatment with indomethacin (a cyclooxygenase inhibitor) and furegrelate (a thromboxane synthase inhibitor) attenuated the 2-DG-induced elevations of both noradrenaline and adrenaline levels. Furthermore, 2-DG administration elevated the thromboxane B2 level, a metabolite of thromboxane A2 in PVN microdialysates. Our results suggest that glucoprivation-induced activation of α- and β-adrenergic receptor in the brain including the PVN and then thromboxane A2 production in the PVN, which are essential for the 2-DG-induced elevations of both plasma adrenaline and noradrenaline levels.

The novel mechanism of bitter taste receptors attenuating rat ventricular contractility

BackgroundBitter taste receptors (TAS2Rs) are a family of G‐protein coupled receptors, firstly identified in the tongue. Recent advances show the expression of TAS2Rs in extra‐oral organs, such as trachea, gastrointestinal tract, and heart. These findings raised up the interest of studying the physiological functions of TAS2Rs besides taste sensing. It has been demonstrated that the activation of TAS2Rs activates gustducin and release Gβγ, which leads to the inhibition of L‐type Ca2+ channels and the consequent airway smooth muscle relaxation.AimThis study investigates the expression of TAS2Rs in rat heart, and the mechanism of bitter compounds regulation of the contractility of cardiac muscle.MethodsRats were excised by thoracotomy and left ventricle strips were isolated. The strips were processed to study the expression levels of TAS2Rs mRNA by real time quantitative PCR (qPCR). Langendorff isolated heart models were used to record the left ventricle pressure and heart rate. Isometric tension recordings were used to measure electrical field stimulation (EFS,1 Hz – 5 V) and epinephrine‐induced contractions in combination with bitter compounds, denatonium and quinine. The conventional whole‐cell patch clamp techniques were used to record the voltage activated L‐type Ca2+ channel currents. The statistic data are expressed as mean ± SEM.ResultsWe detected the mRNA of 6 bitter receptors, TAS2R108, 120, 121, 126, 135, and 143 in the left ventricle tissues and isolated cardiomyocytes of rat, in which the mRNA level of TAS2R120 is the highest among the six followed by TAS2R143 and 121.In isolated perfused rat hearts denatonium (50 μM) reduced the heart rate from 235 ± 3 to 101 ± 12 (N=4). In isolated left ventricle strips, EFS and epinephrine induced phasic contractions which were inhibited completely by tetracaine (100 μM), a ryanodine channel blocker. Denatonium and quinine inhibited EFS‐induced ventricular contractions amplitude and frequency in a concentration dependent manner (N=6, n=6). Both of denatonium and quinine, at concentrations of 10 to 200 μM, caused a complete inhibition of epinephrine (10 μM)‐elicited phasic contractions (N=6, n=6).Nifedipine (10 μM), a selective L‐type Ca2+ channel blocker, partially inhibited EFS‐induced contractions, and the subsequent addition of denatonium (200 μM) and quinine (200 μM) cause a further and complete inhibition of the contractions (N=5, n=5). The non‐selective β‐adrenergic receptor antagonist, propranolol, did not have any effect on the EFS‐induced contractions. In isolated ventricular cardiomyocytes, denatonium (10 μM) reduced the L‐type Ca2+ channel currents density at 10 mV from 4.0 pA/pF to 1.6 pA/pF.ConclusionBitter taste receptor agonists, denatonium and quinine, induce negative ionotropic effects in rat hearts. Our data provide mechanistic evidence that TAS2Rs agonists can inhibit the cardiac contractions by attenuating the L‐type Ca2+ channels, and the consequent Ca2+ release by ryanodine receptors. TAS2Rs agonists can be useful pharmacological tools for the treatment of ventricular tachycardia.Support or Funding InformationSupported by Southwest University and the International Affair Agency of ChongqingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Evidence for β-adrenergic modulation of sweating during incremental exercise in habitually trained males.

The aim of the present study was to determine the β-adrenergic contribution to sweating during incremental exercise in habitually trained males. Nine habitually trained and 11 untrained males performed incremental cycling until exhaustion (20 W/min). Bilateral forearm sweat rates (ventilated capsule) were measured at two skin sites that were transdermally administered via iontophoresis with either 1% propranolol (Propranolol, a nonselective β-adrenergic receptor antagonist) or saline (Control). The sweat rate was evaluated as a function of both relative (percentage of maximum workload) and absolute exercise intensities. The sweat rate at the Propranolol site was lower than the control during exercise at 80 (0.57 ± 0.21 and 0.45 ± 0.19 mg·cm-2·min-1 for Control and Propranolol, respectively) and 90% (0.74 ± 0.22 and 0.65 ± 0.17 mg·cm-2·min-1, respectively) of maximum workload in trained males (all P < 0.05). By contrast, no between-site differences in sweat rates were observed in untrained counterparts (all P > 0.05). At the same absolute intensity, higher sweat rates on the control site were observed in trained males relative to the untrained during exercise at 160 (0.23 ± 0.20 and 0.04 ± 0.05 mg·cm-2·min-1 for trained and untrained, respectively) and 180 W (0.40 ± 0.20 and 0.13 ± 0.13 mg·cm-2·min-1, respectively) (all P < 0.05), whereas this between-group difference was not observed at the Propranolol site (all P > 0.05). We show that the β-adrenergic mechanism does modulate sweating during exercise at a submaximal high relative intensity in habitually trained males. The β-adrenergic mechanism may in part contribute to the greater sweat production in habitually trained males than in untrained counterparts during exercise.NEW & NOTEWORTHY We demonstrated for the first time that the β-adrenergic mechanism does modulate sweating (i.e., β-adrenergic sweating) during exercise using a localized β-adrenoceptor blockade in humans in vivo. β-Adrenergic sweating was evident in habitually trained individuals during exercise at a submaximal high relative intensity (80-90% maximal work). This observation advances our understanding of human thermoregulation during exercise and of the mechanism that underlies sweat gland adaptation to habitual exercise training.

Abstract 2617: Protective effect of the β-blocker carvedilol on UVB-induced skin damage

Abstract The response to ultraviolet (UV) radiation is the primary etiologic factor leading to carcinogenesis of the skin. The effects of UV radiation on the skin is generally transient, but the long term consequences can be carcinogenic. Despite growing public awareness and the use of sunscreen to prevent skin cancer, the incidence continues to rise, and therefore there is a need to develop innovative chemoprevention strategies. Previously, we showed that the receptor subtype nonselective β-adrenergic receptor antagonist (i.e., β-blocker) carvedilol prevented EGF and UVB-mediated neoplastic transformation of the mouse epidermal cell line JB6 P+, indicating its chemopreventive potential against skin cancer. To demonstrate the in vivo effects of carvedilol, in the present study, hairless SKH-1 mice were irradiated for two weeks with 200 mJ/cm2 of UVB and drugs were topically applied immediately after the radiation. Since carvedilol is able to absorb UV, its analogue 4-hydroxycarbazole, which has the same UVB absorption profiling as carvedilol but does not function as a β-blocker, was included as a sunscreen control. Significant skin thickening measured by bi-fold skin thickness on the dorsal skin was observable within a week and over the course of the two-week period. Treatment with carvedilol, but not the analogue, reduced UVB-induced skin hyperplasia, reddening and inflammation. Furthermore, carvedilol, but not the analogue, reduced H2O2 and UVB- induced cytotoxicity and reactive oxygen species production in JB6 P+ cells. To elucidate the molecular mechanism(s) for carvedilol's chemopreventive activity, the signaling profile for JB6 P+ cells treated with EGF and/or carvedilol for 15 min was examined using a Phospho Explorer Antibody Microarray containing 1318 site and phosphor-specific antibodies from over 30 signaling pathways. The antibody array data suggested that the phosphorylation of the intracellular signaling pathways involved in skin carcinogenesis, AP-1 and NF-kB, were increased by EGF but attenuated by carvedilol. These results were validated using luciferase reporter assays. The array data also suggested that carvedilol was able to induce the expression of tumor suppressors p53 and PTEN. In addition, the checkpoint kinases CHK1 and CHK2 and other cell-cycle regulators such as cyclins were also upregulated by carvedilol, suggesting a role in carvedilol's protective effect. Since highly abundant mutations are observable in sun-exposed skin, our current work is to examine the effects of carvedilol on the production of cyclo-pyrimidine dimers (CPDs) induced by UVB. In conclusion, our study has demonstrated novel mechanisms underlying carvedilol's chemopreventive activity against skin cancer. Since carvedilol and other β-blockers are FDA approved drugs and relatively safe, they may offer a new approach of prevention for UVB-induced skin cancer. Citation Format: Kevin M. Huang, Kristan H. Cleveland, Steven Yeung, Bradley T. Andresen, Ying Huang. Protective effect of the β-blocker carvedilol on UVB-induced skin damage. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2617.

Propranolol sensitizes thyroid cancer cells to cytotoxic effect of vemurafenib.

Treatment options for advanced metastatic or progressive thyroid cancers are limited. Although targeted therapy specifically inhibiting intracellular kinase signaling pathways has markedly changed the therapeutic landscape, side-effects and resistance of single agent targeted therapy often leads to termination of the treatment. The objective of the present study was to identify the antitumor property of the non-selective β-adrenergic receptor antagonist propranolol for thyroid cancers. Human thyroid cancer cell lines 8505C, K1, BCPAP and BHP27 were used in the present study. Broad β-blocker propranolol and β2-specific antagonist ICI118551, but not β1-specific antagonist atenolol, inhibited the growth of 8505C and K1 cells. Propranolol treatment inhibited growth and induced apoptosis of 8505C cells invitro and invivo, which are closely associated with decreased expressions of cyclinD1 and anti-apoptotic Bcl-2. Expression of hexokinase2 (HK2) and glucose transporter1 (GLUT1) also decreased following propranolol intervention. 18F-FDG PET/CT imaging of the 8505C xenografts validated shrinkage of the tumors in the propranolol-treated group when compared to the phosphate‑buffered saline treated group. Finally, we found that propranolol can amplify the cytotoxicity of vemurafenib and sensitize thyroid cancer cells to cytotoxic effect of vemurafenib. Our present results suggest that propranolol has potential activity against thyroid cancers and investigation of the combination with targeted molecular therapy for progressive thyroid cancers could be beneficial.

Carvedilol-responsive microRNAs, miR-199a-3p and -214 protect cardiomyocytes from simulated ischemia-reperfusion injury.

The nonselective β-adrenergic receptor antagonist (β-blocker) carvedilol has been shown to protect against myocardial injury, but the detailed underlying mechanisms are unclear. We recently reported that carvedilol stimulates the processing of microRNA (miR)-199a-3p and miR-214 in the heart via β-arrestin1-biased β1-adrenergic receptor (β1AR) cardioprotective signaling. Here, we investigate whether these β-arrestin1/β1AR-responsive miRs mediate the beneficial effects of carvedilol against simulated ischemia/reperfusion (sI/R). Using cultured cardiomyocyte cell lines and primary cardiomyocytes, we demonstrate that carvedilol upregulates miR-199a-3p and miR-214 in both ventricular and atrial cardiomyocytes subjected to sI/R. Overexpression of the two miRs in cardiomyocytes mimics the effects of carvedilol to activate p-AKT survival signaling and the expression of a downstream pluripotency marker Sox2 in response to sI/R. Moreover, carvedilol-mediated p-AKT activation is abolished by knockdown of either miR-199a-3p or miR-214. Along with previous studies to directly link the cardioprotective actions of carvedilol to upregulation of p-AKT/stem cell markers, our findings suggest that the protective roles of carvedilol during ischemic injury are in part attributed to activation of these two protective miRs. Loss of function of miR-199a-3p and miR-214 also increases cardiomyocyte apoptosis after sI/R. Mechanistically, we demonstrate that miR-199a-3p and miR-214 repress the predictive or known apoptotic target genes ddit4 and ing4, respectively, in cardiomyocytes. These findings suggest pivotal roles for miR-199a-3p and miR-214 as regulators of cardiomyocyte survival and contributors to the functional benefits of carvedilol therapy.

Anxiolytic effect of the GPR103 receptor agonist peptide P550 (homolog of neuropeptide 26RFa) in mice. Involvement of neurotransmitters

The GPR103 receptor is a G protein-coupled receptor, which plays a role in several physiological functions. However, the role of the GPR103 receptor in anxiety has not been clarified. The first aim of our study was to elucidate the involvement of the GPR103 receptor in anxious behavior. Mice were treated with peptide P550, which is the mouse homolog of neuropeptide 26RFa and has similar activity for the GPR103 receptor as neuropeptide 26RFa. The anxious behavior was investigated using an elevated plus-maze paradigm. The second aim of our study was to investigate the underlying neurotransmissions. Accordingly, mice were pretreated with a nonselective muscarinic acetylcholine receptor antagonist, atropine, a γ-aminobutyric acid subunit A (GABAA) receptor antagonist, bicuculline, a non-selective 5-HT2 serotonergic receptor antagonist, cyproheptadine, a mixed 5-HT1/5-HT2 serotonergic receptor antagonist, methysergide, a D2, D3, D4 dopamine receptor antagonist, haloperidol, a nonselective α-adrenergic receptor antagonist, phenoxybenzamine and a nonselective β-adrenergic receptor antagonist, propranolol. Our results demonstrated that peptide P550 reduces anxious behavior in elevated plus maze test in mice. Our study shows also that GABAA-ergic, α- and β-adrenergic transmissions are all involved in this action, whereas 5-HT1 and 5-HT2 serotonergic, muscarinic cholinergic and D2, D3, D4 dopaminergic mechanisms may not be implicated.

Ocular Metabolism of Levobunolol: Historic and Emerging Metabolic Pathways

Although ocular transport and delivery have been well studied, metabolism in the eye is not well documented, even for clinically available medications such as levobunolol, a potent and nonselective β-adrenergic receptor antagonist. Recently, we reported an in vitro methodology that could be used to evaluate ocular metabolism across preclinical species and humans. The current investigation provides detailed in vitro ocular and liver metabolism of levobunolol in rat, rabbit, and human S9 fractions, including the formation of equipotent active metabolite, dihydrolevobunolol, with the help of high-resolution mass spectrometry. 11 of the 16 metabolites of levobunolol identified herein, including a direct acetyl conjugate of levobunolol observed in all ocular and liver fractions, have not been reported in the literature. The study documents the identification of six human ocular metabolites that have never been reported. The current investigation presents evidence for ocular and hepatic metabolism of levobunolol via non-cytochrome P450 pathways, which have not been comprehensively investigated to date. Our results indicated that rat liver S9 and human ocular S9 fractions formed the most metabolites. Furthermore, liver was a poor in vitro surrogate for eye, and rat and rabbit were poor surrogates for human in terms of the rate and extent of levobunolol metabolism.

Hemangiomas and β-Blockers: On the Rebound.

* Abbreviations: IH — : infantile hemangioma OP — : oral propranolol Infantile hemangioma (IH) is the most common tumor of childhood, and although most lesions eventually involute, the proliferative phase may be associated with complications, such as ulceration, bleeding, functional compromise, and anatomic disfigurement. Rarely, IH can have major or life-threatening consequences, such as airway obstruction, high-output congestive heart failure, and consumptive hypothyroidism. It is for reasons such as these that therapy may be indicated. Propranolol, a nonselective β-adrenergic receptor antagonist, has been used off-label in children for years in the treatment of cardiac dysrhythmias, congestive heart failure, and hypertension. In 2008, Leaute-Labreze et al1 reported their discovery of its benefits against IH, an observation confirmed in their follow-up report of 32 infants 1 year later.2 Oral propranolol (OP) has evolved to become the standard of care for IH therapy. In 2014, a pediatric formulation was approved by the US Food and Drug Administration (March) and the European Medicines Agency (April).3,4 The results of the multicenter, randomized, double-blind, adaptive phase 2-3 trial assessing its efficacy and safety in treating IH were published in 2015.5 Although the precise mechanisms of … Address correspondence to Anthony J. Mancini, MD, Ann and Robert H. Lurie Children’s Hospital of Chicago, 225 E. Chicago Ave, Mailbox 107, Chicago, IL 60611. E-mail: amancini{at}northwestern.edu

Pudendal but not tibial nerve stimulation inhibits bladder contractions induced by stimulation of pontine micturition center in cats.

This study examined the possibility that pudendal nerve stimulation (PNS) or tibial nerve stimulation (TNS) inhibits the excitatory pathway from the pontine micturition center (PMC) to the urinary bladder. In decerebrate cats under α-chloralose anesthesia, electrical stimulation of the PMC (40 Hz frequency, 0.2-ms pulse width, 10-25 s duration) using a microelectrode induced bladder contractions >20 cmH2O amplitude when the bladder was filled to 60-70% capacity. PNS or TNS (5 Hz, 0.2 ms) at two and four times the threshold (2T and 4T) to induce anal or toe twitch was applied to inhibit the PMC stimulation-induced bladder contractions. Propranolol, a nonselective β-adrenergic receptor antagonist, was administered intravenously (1 mg/kg i.v.) to determine the role of sympathetic pathways in PNS/TNS inhibition. PNS at both 2T and 4T significantly (P < 0.05) reduced the amplitude and area under the curve of the bladder contractions induced by PMC stimulation, while TNS at 4T facilitated the bladder contractions. Propranolol completely eliminated PNS inhibition and TNS facilitation. This study indicates that PNS, but not TNS, inhibits PMC stimulation-induced bladder contractions via a β-adrenergic mechanism that may occur in the detrusor muscle as a result of reflex activity in lumbar sympathetic nerves. Neither PNS nor TNS activated a central inhibitory pathway with synaptic connections to the sacral parasympathetic neurons that innervate the bladder. Understanding the site of action involved in bladder neuromodulation is important for developing new therapies for bladder disorders.

The action of neuropeptide AF on passive avoidance learning. Involvement of neurotransmitters

Neuropeptide AF (NPAF) is an amidated octadecapeptide, which is member of the RFamide peptide family. NPAF is encoded by the farp-1 gene and acts through the G protein coupled NPFF-1 and NPFF-2 receptors. NPAF is involved in several physiological functions of the central nervous system, however we have little evidence about the involvement of NPAF in learning and memory. Therefore, the aim of the present study was to investigate the action of NPAF on consolidation of memory in a passive avoidance learning paradigm in mice. We have also investigated the underlying neurotransmissions and the action of NPAF on β-amyloid-induced memory impairment. Accordingly, mice were pretreated with a nonselective muscarinic acetylcholine receptor antagonist, atropine, a non-selective 5-HT2 serotonergic receptor antagonist, cyproheptadine, a mixed 5-HT1/5-HT2 serotonergic receptor antagonist, methysergide, a D2, D3, D4 dopamine receptor antagonist, haloperidol, a non-selective opioid receptor antagonist, naloxone, a nitric oxide synthase inhibitor, nitro-l-arginine, a α1/α2β-adrenergic receptor antagonist, prazosin, a nonselective β-adrenergic receptor antagonist, propranolol or β-amyloid 25–35 in combination with NPAF administration. Our results demonstrate for the first time that NPAF improves the consolidation of passive avoidance learning. This effect is mediated through muscarinic cholinergic, 5HT1- and 5HT2-serotoninergic, dopaminergic, nitrergic and α- and β-adrenergic neurotransmissions, but not by opioid transmission, since atropine, cyproheptadine, methysergide, haloperidol, nitro-l-arginine, prazosin and propranolol reversed the action of NPAF, whereas naloxone was ineffective. The present study also shows that NPAF reverses the β-amyloid 25–35-induced memory impairment.