Propranolol treatment of infantile hemangioma endothelial cells: A molecular analysis

A novel hsa_circ_0006903 circular RNA promotes tumor development and dendritic cells activated expression in infantile hemangioma

Background

Increasing reports revealed that circular RNAs (circRNAs) and immune cells infiltration were related with tumor development. However, its role in infantile hemangioma (IH) is unknown. We will explore a novel hsa_circ_0006903-based ceRNA network and investigate the landscape of dendritic cells activated expression in IH.

Material and methods

Differentially expressed circRNAs (DECs) were identified from Gene Expression Omnibus (GEO) database. Regulatory networks and functional enrichment analysis were constructed. CIBERSORT was used to characterize immune cells composition. qRT-PCR was performed to detect the expression of hsa_circ_0006903 in cell lines. Then, the role of hsa_circ_0006903 in IH were validated in vitro using transwell assay. Immunofluorescence was applied to the colocalization of CD11b for dendritic cells activated as a biomarker in IH tissues.

Results

Using GEO database, a total of 67 DECs were screened out in IH. Hsa_circ_0006903 was the most significant DECs. Then, a novel hsa_circ_0006903 circular RNA-ceRNA network was constructed. Mechanistically, functional enrichment analysis showed that the p53 signaling pathway played the most important roles, and hsa_circ_0006903/miR-6721-5p/CACNA2D2 and hsa_circ_0006903/miR-4786-3p/ATP13A4 axis were identified. CACNA2D2, ATP13A4, and P53 were significantly downregulated in IH cell lines. We validated that dendritic cell activated was significantly overexpressed. Moreover, CD11b as a biomarker of dendritic cells activated were tested in IH tissues. Finally, hsa_circ_0006903 was significantly overexpressed, and hsa_circ_0006903 promoted infantile hemangioma cell proliferation, invasion, and migration in vitro.

Conclusion

Overall, our study revealed that a novel hsa_circ_0006903 promoted tumor progression, and indicated a potential biomarker CD11b of dendritic cells activated in IH.

Ocular and orbital tumors in childhood

Pediatric tumors of the eye and orbit can be benign or malignant as well as congenital or acquired and are usually distinctively different than those seen in adults. Although most of these neoplasms are benign (eg, dermoid cyst, chalazion, molluscum), their location near and within a vital organ can result in serious dermatologic and ophthalmologic sequelae. Lesions discussed include vascular lesions, retinoblastomas (the most common primary pediatric intraocular malignancy), rhabdomyosarcoma (the most common primary pediatric orbital malignancy), Langerhans cell histiocytosis, and metastatic lesions to the orbit (neuroblastoma, Ewing sarcoma). Although cysts and ocular melanoma can occur within the pediatric population, these conditions are covered in other contributions in this issue of Clinics in Dermatology.

Infantile hemangioma: the common and enigmatic vascular tumor

Infantile hemangioma (IH) is a benign vascular tumor that occurs in 5% of newborns. The tumor follows a life cycle of rapid proliferation in infancy, followed by slow involution in childhood. This unique life cycle has attracted the interest of basic and clinical scientists alike as a paradigm for vasculogenesis, angiogenesis, and vascular regression. Unanswered questions persist about the genetic and molecular drivers of the proliferating and involuting phases. The beta blocker propranolol usually accelerates regression of problematic IHs, yet its mechanism of action on vascular proliferation and differentiation is unclear. Some IHs fail to respond to beta blockers and regrow after discontinuation. Side effects occur and long-term sequelae of propranolol treatment are unknown. This poses clinical challenges and raises novel questions about the mechanisms of vascular overgrowth in IH.

R-Propranolol Has Broad-Spectrum Anti-Coronavirus Activity and Suppresses Factors Involved in Pathogenic Angiogenesis

The SARS-CoV-2 pandemic highlighted the need for broad-spectrum antivirals to increase our preparedness. Patients often require treatment by the time that blocking virus replication is less effective. Therefore, therapy should not only aim to inhibit the virus, but also to suppress pathogenic host responses, e.g., leading to microvascular changes and pulmonary damage. Clinical studies have previously linked SARS-CoV-2 infection to pathogenic intussusceptive angiogenesis in the lungs, involving the upregulation of angiogenic factors such as ANGPTL4. The β-blocker propranolol is used to suppress aberrant ANGPTL4 expression in the treatment of hemangiomas. Therefore, we investigated the effect of propranolol on SARS-CoV-2 infection and the expression of ANGPTL4. SARS-CoV-2 upregulated ANGPTL4 in endothelial and other cells, which could be suppressed with R-propranolol. The compound also inhibited the replication of SARS-CoV-2 in Vero-E6 cells and reduced the viral load by up to ~2 logs in various cell lines and primary human airway epithelial cultures. R-propranolol was as effective as S-propranolol but lacks the latter's undesired β-blocker activity. R-propranolol also inhibited SARS-CoV and MERS-CoV. It inhibited a post-entry step of the replication cycle, likely via host factors. The broad-spectrum antiviral effect and suppression of factors involved in pathogenic angiogenesis make R-propranolol an interesting molecule to further explore for the treatment of coronavirus infections.

TIMolol Nasal Spray as a Treatment for Epistaxis in Hereditary Hemorrhagic Telangiectasia (TIM-HHT)—A Prospective, Randomized, Double-Blind, Controlled, Cross-Over Trial

To date, there is no approved local therapeutic agent for the treatment of epistaxis due to hereditary hemorrhagic telangiectasia (HHT). Several case reports suggest the topical use of timolol. This monocentric, prospective, randomized, placebo-controlled, double-blinded, cross-over study investigated whether the effectiveness of the standard treatment with a pulsed diode laser can be increased by also using timolol nasal spray. The primary outcome was severity of epistaxis after three months, while the main secondary outcome was severity of epistaxis and subjective satisfaction after one month. Twenty patients were allocated and treated, of which 18 patients completed both 3-month treatment sequences. Timolol was well tolerated by all patients. Epistaxis Severity Score after three months, the primary outcome measure, showed a beneficial, but statistically nonsignificant (p = 0.084), effect of additional timolol application. Epistaxis Severity Score (p = 0.010) and patients’ satisfaction with their nosebleeds after one month (p = 0.050) showed statistically significant benefits. This placebo-controlled, randomized trial provides some evidence that timolol nasal spray positively impacts epistaxis severity and subjective satisfaction in HHT patients when additively applied to standard laser therapy after one month. However, the effect of timolol was observed to diminish over time. Trials with larger sample sizes are warranted to confirm these findings.

Β-blockers activate autophagy on infantile hemangioma-derived endothelial cells in vitro

The mechanisms underlying the success of propranolol in the treatment of infantile hemangioma (IH) remain elusive and do not fully explain the rapid regression of hemangiomatous lesions following drug administration. As autophagy is critically implicated in vascular homeostasis, we determined whether β-blockers trigger the autophagic flux on infantile hemangioma-derived endothelial cells (Hem-ECs) in vitro.

MATERIAL AND METHODS

Fresh tissue specimens, surgically removed for therapeutic purpose to seven children affected by proliferative IH, were subjected to enzymatic digestion. Cells were sorted with anti-human CD31 immunolabeled magnetic microbeads. Following phenotypic characterization, expanded Hem-ECs, at P2 to P6, were exposed to different concentrations (50 μM to 150 μM) of propranolol, atenolol or metoprolol alone and in combination with the autophagy inhibitor Bafilomycin A1. Rapamycin, a potent inducer of autophagy, was also used as control. Autophagy was assessed by Lysotracker Red staining, western blot analysis of LC3BII/LC3BI and p62, and morphologically by transmission electron microscopy.

RESULTS

Hem-ECs treated with either propranolol, atenolol or metoprolol displayed positive LysoTracker Red staining. Increased LC3BII/LC3BI ratio, as well as p62 modulation, were documented in β-blockers treated Hem-ECs. Abundant autophagic vacuoles and multilamellar bodies characterized the cytoplasmic ultrastructural features of autophagy in cultured Hem-ECs exposed in vitro to β-blocking agents. Importantly, similar biochemical and morphologic evidence of autophagy were observed following rapamycin while Bafilomycin A1 significantly prevented the autophagic flux promoted by β-blockers in Hem-ECs.

CONCLUSION

Our data suggest that autophagy may be ascribed among the mechanisms of action of β-blockers suggesting new mechanistic insights on the potential therapeutic application of this class of drugs in pathologic conditions involving uncontrolled angiogenesis.

VEGF Pathway Gene Expression Profile of Proliferating versus Involuting Infantile Hemangiomas: Preliminary Evidence and Review of the Literature

Background. Infantile hemangiomas may have unexpected behavior. Initial regression (spontaneously or drug-induced) may be followed by unexplained recurrences. At this moment, there are no well-established criteria to predict infantile hemangioma reccurrences. Methods. We compared the VEGF pathway gene expression profile for one case of involuting infantile hemangioma versus one case of recurrent proliferative infantile hemangioma using TaqMan Array. Results. We found ten genes upregulated for both involuting and recurrent proliferative hemangiomas: ACTB, KRAS, MAP2K1, HRAS, NOS3, BAD, HSPB1, HPRT1, GUSB, and CASP9. Thirteen genes were downregulated for both involuting and proliferative hemangiomas: FIGF, ACTG1, GRB2, MAPKAPK2, ACTG2, MAP2K2, MAPK3, HSP90AA1, MAP2K6, NRAS, ACTA1, KDR, and MAPK1. Three genes showed divergent expression between proliferating and involuting hemangiomas. Proliferating hemangioma had MAPK14 and AKT1 gene upregulation and ACTA2 downregulation. Involuting infantile hemangioma was characterized by ACTA2 upregulation and AKT1 and MAPK14 downregulation. Conclusions. Three genes, AKT1, p38/MAPK14, and ACTA2, were found to have divergent expression in proliferating and involuting infantile hemangiomas. Excepting AKT1, which was mentioned in the last ISSVA classification (strictly related to Proteus Syndrome), none of the other genes were reported. An accurate gene expression profile mapping of infantile hemangiomas together with a gene expression-based hemangioma classification is stringently needed.

Comparative Efficacy of Antihypertensive Agents in Flow-Mediated Vasodilation of Patients with Hypertension: Network Meta-Analysis of Randomized Controlled Trial

Hypertension induces both structural and functional changes in blood vessels, thereby increasing endothelial dysfunction, which in turn, contributes to an increase in blood pressure. A popular and widely used noninvasive tool, flow-mediated dilation (FMD), is used to examine peripheral artery endothelium-dependent dilation. This study aimed to compare the efficacies of different classes of antihypertensive agents based on their effects on FMD. PubMed, Embase, and Cochrane Library were queried till November 1, 2020. Comparative studies on the efficacies of two or more antihypertensive agents or placebos for hypertensive patients were included. The outcomes were variations in mean systolic and diastolic blood pressure. Two reviewers independently reviewed and filtered the literature and extracted the data; the Cochrane “risk of bias” method was used to evaluate the methodological quality of the randomized controlled trials. A network meta-analysis was performed using Stata 15.0 software with a total of 49 studies. Subgroup analysis based on age and duration of treatments was performed. As compared to the placebo group, patients receiving the antihypertensive drugs exhibited significantly enhanced FMD (ARB + CCB: 4.01%, 95% CI, 0.92–7.11%, p < 0.001; ACEI + ARB: 2.81%, 95% CI, 1.19–4.43%, p < 0.001; ACEI: 2.55%, 95% CI, 1.34–3.77%, p < 0.001; ARB: 2.22%, 95% CI, 1.05–3.38%, p < 0.001; β-blocker: 2.23%, 95% CI, 0.93–3.52%, p < 0.001). In the SUCRA curve for network meta-analysis, the combination of CCB and ARB was found to be the most effective in increasing FMD (SUCRA = 89.0%), followed by ACEI monotherapy (SUCRA = 74.2%). ARB combined with CCB was superior in improving the endothelial function measured as the FMD; ACEI monotherapy was the most effective treatment among the antihypertension medications. There were no significant differences between antihypertensive drug-based monotherapies.

Nasal Obstruction in the Infant

Neonatal nasal obstruction is common in both the hospital and clinic settings. Causes can range from rhinitis to congenital masses, with a wide variety of congenital nasal masses described. A complete history and physical examination are necessary for correct diagnosis and management. Arhinia and bilateral choanal atresia will present with complete obstruction leading to forced mouth breathing. Partial obstruction will require assessment of nasal patency with possible nasal endoscopy and imaging. Medical and surgical options for treatment are discussed.

A transcription factor is the target of propranolol treatment in infantile hemangioma

Propranolol is a nonselective β-adrenergic receptor (AR) blocker that has been the first-line therapy for problematic infantile hemangioma (IH), the most frequent childhood vascular tumor. Although IHs are benign and eventually regress spontaneously, at least 15% of patients require treatment. Despite the extensive use of propranolol for IH treatment, its mode of action remains unclear. In this issue of the JCI, Seebauer et al. investigated the cellular and molecular consequences of propranolol treatment on IH vascular tumor formation in a murine model of IH. The efficacy of propranolol was independent of its β-AR blocker activity and was attributable to the direct targeting of the transcription factor SOX18, which, in turn, reduced hemangioma blood vessel formation. We believe these results will guide clinical translation for the use of more efficient and safer therapies for IH and possibly for other vascular anomalies in which SOX18 plays a role.

Oral Atenolol versus Propranolol in the Treatment of Infantile Hemangioma: A Systematic Review and Meta-Analysis

Background

Infantile hemangioma (IH) is the most common benign vascular tumor of infancy. Propranolol is considered first-line therapy for IH. However, it is associated with side effects. Therefore, there was a need for alternative therapy. Atenolol, a selective b1-blocker may be free from such side effects. Hence, the present study aims to develop a more accurate estimate of the safety and efficacy of atenolol compared to propranolol in the treatment of IH.

Methodology

A search of various literature databases (PubMed, Embase, Ovid, Scopus, Cochrane Central, CINAHL, Web of Science, and Google Scholar) was done to identify studies which compared propranolol versus atenolol in the treatment of IH. The combined odds ratio along with corresponding 95% confidence intervals (CIs) were evaluated using a fixed-effects model.

Results

A total of 300 articles were screened of which five studies including 116 patients in atenolol arm and 138 patients in the propranolol arm were analyzed. Atenolol was comparable to propranolol in terms of efficacy as no significant difference was seen between both the treatment arms in terms of hemangioma activity score (mean difference 0.25 [95% CI;‒0.21, 0.71]) and complete response (odds ratio [OR] =0.43; 95% CI; 0.17, 1.11; P = 0.08,). Atenolol therapy was better than propranolol in terms of safety, i.e., serious/potentially serious side effect, (OR = 0.11; 95% CI; 0.02, 0.51; P = 0.005) and wheezing/bronchial hyperreactivity (OR = 0.11; 95% CI; 0.02, 0.51; P = 0.005).

Conclusion

The present meta-analysis provides evidence that atenolol has got a comparable efficacy and better safety profile with propranolol.

Infantile hemangiomas β3-adrenoceptor overexpression is associated with nonresponse to propranolol

BACKGROUND

Propranolol (antagonist of β₁-/β₂-AR but minimally active against β₃-AR) is currently the first-line treatment for infantile hemangiomas (IH). Its efficacy is attributed to the blockade of β₂-AR. However, its success rate is ~60%. Considering the growing interest in the angiogenic role of β₃-ARs, we evaluated a possible relationship between β₃-AR expression and response to propranolol.

METHODS

Fifteen samples of surgical biopsies were collected from patients with IH. Three were taken precociously from infants and then successfully treated with propranolol (responder group). Twelve were taken later, from residual lesions noncompletely responsive to propranolol (nonresponder group). A morphometrical analysis of the percentage of β₁-, β₂-, and β₃-ARs positively stained area was compared between the two groups.

RESULTS

While no difference was found in both β₁- and β₂-AR expression level, a statistically significant increase of β₃-AR positively stained area was observed in the nonresponder group.

CONCLUSIONS

Although the number of biopsies is insufficient to draw definitive conclusions, and the different β-AR pattern may be theoretically explained by the different timing of samplings, this study suggests a possible correlation between β₃-AR expression and the reduced responsiveness to propranolol treatment. This study could pave the way for new therapeutic perspectives to manage IH.

IMPACT

Propranolol (unselective antagonist of β₁ and β₂-ARs) is currently the first-line treatment for IHs, with a success rate of ~60%. Its effectiveness has been attributed to its ability to block β₂-ARs. However, β₃-ARs (on which propranolol is minimally active) were significantly more expressed in hemangioma biopsies taken from patients nonresponsive to propranolol. This study suggests a possible role of β₃-ARs in hemangioma pathogenesis and a possible new therapeutic target.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Beta-Blockers and Berberine: A Possible Dual Approach to Contrast Neuroblastoma Growth and Progression

The use of nutraceuticals during cancer treatment is a long-lasting debate. Berberine (BBR) is an isoquinoline quaternary alkaloid extracted from a variety of medicinal plants. BBR has been shown to have therapeutic effects in different pathologies, particularly in cancer, where it affects pathways involved in tumor progression. In neuroblastoma, the most common extracranial childhood solid tumor, BBR, reduces tumor growth by regulating both stemness and differentiation features and by inducing apoptosis. At the same time, the inhibition of β-adrenergic signaling leads to a reduction in growth and increase of differentiation of neuroblastoma. In this review, we summarize the possible beneficial effects of BBR in counteracting tumor growth and progression in various types of cancer and, in particular, in neuroblastoma. However, BBR administration, besides its numerous beneficial effects, presents a few side effects due to inhibition of MAO A enzyme in neuroblastoma cells. Therefore, herein, we proposed a novel therapeutic strategy to overcome side effects of BBR administration consisting of concomitant administration of BBR together with β-blockers in neuroblastoma.

NOTCH pathway activation in infantile hemangiomas

OBJECTIVE

The objective of this study was to characterize the role of NOTCH signaling cascade activation in the angiogenic drive of infantile hemangioma (IH) tissue.

METHODS

Both IH tissue and normal skin were collected from 55 surgical patients. Of these, 14 were proliferating hemangiomas, 14 were stationary, 14 were involuted, and 13 had been treated with propranolol. Protein and RNA were extracted from all tissues and subjected to Western blotting and reverse transcription-polymerase chain reaction, respectively, for components of the NOTCH signaling pathway.

RESULTS

Compared with normal skin from the same patients, proliferating IHs contained higher levels of messenger RNA and protein for the majority of NOTCH receptors and ligands as well as the downstream coactivator MAML1. Expression of NOTCH receptor ligand messenger RNA and protein was significantly lower in involuting and propranolol-treated IHs.

CONCLUSIONS

Perturbations in NOTCH signaling follow the natural course and treatment outcome of IHs, suggesting a critical role in their pathogenesis.

The expression and role of glycolysis-associated molecules in infantile hemangioma

AIMS

Infantile hemangioma (IH) is one of the most common tumors in infancy, which etiology and pathogenesis has not been fully elucidated, hypoxia and abnormal glucose metabolism is regarded as critical pathogenic factors. This study investigated the expression and function of glycolysis-associated molecules (GLUT1, HK2, PFKFB3, PKM2, and LDHA) under normoxic and hypoxic conditions to further understand the pathogenesis of IH.

MAIN METHODS

Hemangioma-derived endothelial cells (HemECs) were isolated from proliferating phase infantile hemangiomas and identified by immunofluorescence. HemECs and human umbilical vein endothelial cells (HUVECs) were cultured under normoxic and hypoxic conditions. RNA and protein expression of glycolysis-associated molecules were analyzed by quantitative real-time RT-PCR, western blotting, and immunohistochemistry. Glucose consumption, ATP production and lactate production were measured. Glycolysis-associated molecules were inhibited by WZB117, 3BP, 3PO, SKN, and GSK 2837808A and the resulting effects on HemECs proliferation, migration, and tube formation were quantified.

KEY FINDINGS

Glycolysis-associated molecules were highly expressed at both mRNA and protein levels in HemECs compared with HUVECs (P < 0.05). Glucose consumption and ATP production were higher in HemECs than in HUVECs, while lactate production in HemECs was lower than in HUVECs (P < 0.05). Inhibition of some glycolysis-associated molecules reduced the proliferation, migration, and tube formation capacity of HemECs (P < 0.05).

SIGNIFICANCE

Our study revealed that glycolysis-associated molecules were highly expressed in IH. Glucose metabolismin HemECs differed from normal endothelial cells. Altering the expression of glycolysis-associated molecules may influence the phenotype of HemECs and provide new therapeutic approaches to the successful treatment of IH.

Propranolol Attenuates Proangiogenic Activity of Mononuclear Phagocytes: Implication in Choroidal Neovascularization

Purpose

Targeting β-adrenergic receptor signaling with propranolol has emerged as a potential candidate to counteract choroidal neovascularization (CNV). Little is known of its effect on macrophages, which play a critical role in CNV. We investigated the effect of propranolol on angiogenic response of mononuclear phagocytes (MPs).

Methods

The angiogenic effect of propranolol was evaluated in laser-induced CNV model. Mice received intraperitoneal injections of propranolol (6 mg/kg/d) or vehicle. CNV area and inflammatory cells were determined respectively by using lectin staining and an anti-IBA-1 antibody on RPE/choroid flat mounts. Inflammatory gene expression was evaluated by quantitative (q) PCR analysis. Mechanisms of propranolol was studied in MP cell lines J774 and RAW264.7 and in primary peritoneal macrophages. Expression of pro- and antiangiogenic mediators was studied. In addition, effects of propranolol treatment of MPs was assessed on choroidal explant.

Results

CNV was attenuated by propranolol and concomitantly associated with decreased inflammatory mediators IL-6 and TNFα, albeit with accumulation of (β-adrenoceptor harboring) MPs in the CNV area. Conditioned media from MPs preincubated with propranolol exerted antiangiogenic effects. Treatment of J774 confirmed the attenuation of inflammatory response to propranolol and increased cleaved caspase-3 on choroidal explant. We found that propranolol increased pigment epithelium-derived factor (PEDF) expression in MPs. Trapping of PEDF with an antibody abrogated antiangiogenic effects of propranolol. PEDF was also detected in CNV-associated MPs.

Conclusions

We hereby show that propranolol confers on MPs antiangiogenic properties by increasing PEDF expression, which complements its effects on vascular tissue resulting in inhibition of choroidal vasoproliferation in inflammatory conditions. The study supports possible use of propranolol as a therapeutic modality for CNV.

Surgical Intervention of Periocular Infantile Hemangiomas in the Era of β-Blockers

PURPOSE

To examine the role of adjuvant surgical resection of infantile hemangiomas after systemic β-blocker therapy.

METHODS

This is a multicentered retrospective study. Standard protocol for oral propranolol was employed by the referring physicians. Ocular indications for surgery included ptosis obstructing the visual axis, high degrees of astigmatism causing amblyopia, or disfigurement from residual tumor. Patients underwent complete excision or debulking.

RESULTS

Eleven girls and 4 boys were surgically treated with mean operative age of 34.4 months. Patients were followed for a mean of 19.6 months after surgery. Four patients required surgical treatment due to an inability to tolerate medical therapy secondary to drug-related side effects (including bradycardia). The other 11 patients proceeded to surgery due to residual eyelid and orbital lesions despite medical treatment. All 15 patients underwent orbitotomy for residual hemangioma excision. Four patients also underwent simultaneous levator advancement at the time of excision. In all cases, there was resolution of ptosis with clearing of the visual axis. No complications were incurred during the surgical treatment and there were no hemangioma recurrences.

CONCLUSIONS

This is the first study to report surgical management of periocular infantile hemangiomas recalcitrant to standard therapy in the β-blocker era. In patients with infantile hemangioma who have failed medical therapy, adjuvant surgical treatment still plays an important role. For patients with persistent tumor causing ocular sequelae, surgical intervention aimed at soft tissue debulking and ptosis repair can be successful in achieving excellent functional and aesthetic outcomes with minimal side effects.For patients with periocular infantile hemangiomas with residual soft tissue deformity following propranolol therapy, surgical treatment plays an important role in improving functional and cosmetic outcomes with minimal side effects.

β3-adrenoreceptor blockade reduces tumor growth and increases neuronal differentiation in neuroblastoma via SK2/S1P2 modulation

Neuroblastoma (NB) is the most frequently observed among extracranial pediatric solid tumors. It displays an extreme clinical heterogeneity, in particular for the presentation at diagnosis and response to treatment, often depending on cancer cell differentiation/stemness. The frequent presence of elevated hematic and urinary levels of catecholamines in patients affected by NB suggests that the dissection of adrenergic system is crucial for a better understanding of this cancer. β3-adrenoreceptor (β3-AR) is the last identified member of adrenergic receptors, involved in different tumor conditions, such as melanoma. Multiple studies have shown that the dysregulation of the bioactive lipid sphingosine 1-phosphate (S1P) metabolism and signaling is involved in many pathological diseases including cancer. However, whether S1P is crucial for NB progression and aggressiveness is still under investigation. Here we provide experimental evidence that β3-AR is expressed in NB, both human specimens and cell lines, where it is critically involved in the activation of proliferation and the regulation between stemness/differentiation, via its functional cross-talk with sphingosine kinase 2 (SK2)/S1P receptor 2 (S1P₂) axis. The specific antagonism of β3-AR by SR59230A inhibits NB growth and tumor progression, by switching from stemness to cell differentiation both in vivo and in vitro through the specific blockade of SK2/S1P₂ signaling.

The beta adrenergic receptor antagonist propranolol alters mitogenic and apoptotic signaling in late stage breast cancer

Background

Substantial evidence supports the use of inexpensive β-AR antagonists (beta blockers) against a variety of cancers, and the β-AR antagonist propranolol was recently approved by the European Medicines Agency for the treatment of soft tissue sarcomas. Prospective and retrospective data published by our group and others suggest that non-selective β-AR antagonists are effective at reducing proliferative rates in breast cancers, however the mechanism by which this occurs is largely unknown.

Methods

In this study, we measured changes in tumor proliferation and apoptosis in a late stage breast cancer patient treated with neoadjuvant propranolol. We expounded upon these clinical findings by employing an in vitro breast cancer model, where we used cell-based assays to evaluate propranolol-mediated molecular alterations related to cell proliferation and apoptosis.

Results

Neoadjuvant propranolol decreased expression of the pro-proliferative Ki-67 and pro-survival Bcl-2 markers, and increased pro-apoptotic p53 expression in a patient with stage III breast cancer. Molecular analysis revealed that β-AR antagonism disrupted cell cycle progression and steady state levels of cyclins. Furthermore, propranolol treatment of breast cancer cells increased p53 levels, enhanced caspase cleavage, and induced apoptosis.

Conclusion

Collectively, these data provide support for the incorporation of β-AR antagonists into the clinical management of breast cancer, and elucidate a partial molecular mechanism explaining the efficacy of β-AR antagonists against this disease.

Bleeding risk of cerebral cavernous malformations in patients on β-blocker medication: a cohort study

OBJECTIVE

Cerebral cavernous malformations (CCMs) are frequently diagnosed vascular malformations of the brain. Although most CCMs are asymptomatic, some can be responsible for intracerebral hemorrhage or seizures. In selected cases, microsurgical resection is the preferred treatment option. Treatment with the unselective β-blocker propranolol has been presumed to stabilize and eventually lead to CCM size regression in a limited number of published case series; however, the underlying mechanism and evidence for this effect remain unclear. The aim of this study was to investigate the risk for CCM-related hemorrhage in patients on long-term β-blocker medication.

METHODS

A single-center database containing data on patients harboring CCMs was retrospectively interrogated for a time period of 35 years. The database included information about hemorrhage and antihypertensive medication. Descriptive and survival analyses were performed, focusing on the risk of hemorrhage at presentation and during follow-up (first or subsequent hemorrhage) in patients on long-term β-blocker medication versus those who were not. Follow-up was censored at the first occurrence of new hemorrhage, surgery, or the last clinical review. For purposes of this analysis, the β-blocker group was divided into the following main subgroups: any β-blocker, β1-selective β-blocker, and any unselective β-blocker.

RESULTS

Of 542 CCMs among 408 patients, 81 (14.9%) were under treatment with any β-blocker; 65 (12%) received β1-selective β-blocker, and 16 (3%) received any unselective β-blocker. One hundred thirty-six (25.1%) CCMs presented with hemorrhage at diagnosis. None of the β-blocker groups was associated with a lower risk of hemorrhage at the time of diagnosis in a univariate descriptive analysis (any β-blocker: p = 0.64, β1-selective: p = 0.93, any unselective β-blocker: p = 0.25). Four hundred ninety-six CCMs were followed up after diagnosis and included in the survival analysis, for a total of 1800 lesion-years. Follow-up hemorrhage occurred in 36 (7.3%) CCMs. Neither univariate descriptive nor univariate Cox proportional-hazards regression analysis showed a decreased risk for follow-up hemorrhage under treatment with β-blocker medication (any β-blocker: p = 0.70, HR 1.19, 95% CI 0.49-2.90; β1-selective: p = 0.78, HR 1.15, 95% CI 0.44-3.00; any unselective β-blocker: p = 0.76, HR 1.37, 95% CI 0.19-10.08). Multivariate Cox proportional-hazards regression analysis including brainstem location, hemorrhage at diagnosis, age, and any β-blocker treatment showed no reduced risk for follow-up hemorrhage under any β-blocker treatment (p = 0.53, HR 1.36, 95% CI 0.52-3.56).

CONCLUSIONS

In this retrospective cohort study, β-blocker medication does not seem to be associated with a decreased risk of CCM-related hemorrhage at presentation or during follow-up.

Complex Formation between VEGFR2 and the β2-Adrenoceptor

Vascular endothelial growth factor (VEGF) is an important mediator of endothelial cell proliferation and angiogenesis via its receptor VEGFR2. A common tumor associated with elevated VEGFR2 signaling is infantile hemangioma that is caused by a rapid proliferation of vascular endothelial cells. The current first-line treatment for infantile hemangioma is the β-adrenoceptor antagonist, propranolol, although its mechanism of action is not understood. Here we have used bioluminescence resonance energy transfer and VEGFR2 genetically tagged with NanoLuc luciferase to demonstrate that oligomeric complexes involving VEGFR2 and the β₂-adrenoceptor can be generated in both cell membranes and intracellular endosomes. These complexes are induced by agonist treatment and retain their ability to couple to intracellular signaling proteins. Furthermore, coupling of β₂-adrenoceptor to β-arrestin2 is prolonged by VEGFR2 activation. These data suggest that protein-protein interactions between VEGFR2, the β₂-adrenoceptor, and β-arrestin2 may provide insight into their roles in health and disease.

Combined effect of propranolol, vincristine and bevacizumab on HUVECs and BJ cells

Infantile hemangioma is one of the most common benign tumors affecting children, with ~10-15% requiring medical treatment. These tumors consist of endothelial cells and stromal components, including fibroblasts, pericytes and mast cells. Effects of propranolol treatment in combination with bevacizumab or vincristine on cell growth were compared in the current study using human umbilical vein endothelial cells (HUVECs) and BJ human normal fibroblasts (BJs) to determine potential synergic effects in vitro. Inhibition of cell growth was investigated using MTT assays and cytotoxicity of the drugs in various combinations was expressed as half inhibitory concentration (IC₅₀). Apoptosis was investigated using flow cytometry, with Alexa Fluor 488 and propidium iodide. Propranolol inhibited BJ and HUVEC growth in a dose-dependent manner, with increased response observed in BJs (IC50, 148,32 µg/ml; standard error logIC50, 0.07). Treatment with vincristine induced the strongest growth inhibition in HUVECs (IC50, 17,89 µg/ml; standard error log IC50, 0.07) and BJs (IC50, 24,81 µg/ml; standard error log IC50, 0.08) compared with propranolol (HUVEC IC50, 81,94 µg/ml; standard error log IC50, 0.06; BJ-IC50, 148,32 µg/ml; standard error logIC50, 0.07) or bevacizumab (HUVEC IC50 96,91 µg/ml; standard error log IC50, 0.06; BJ IC50, 182,70 µg/ml; standard error log IC50, 0.09) alone. Bevacizumab was the weakest cytotoxic agent. Combination treatment of vincristine with bevacizumab induced the highest levels of apoptosis in HUVECs compared with all other treatments and triple-drug therapy induced the levels of apoptosis in BJs. Single treatment with vincristine, propranolol or bevacizumab induced apoptosis in BJs and HUVECs. In BJs, triple treatment exhibited the greatest influence on apoptosis, compared with single and dual treatments and in HUVECs, vincristine and bevacizumab combination treatment induced apoptosis to the highest level. The present study offers novel perspectives in drug repurposing studies for the three drugs, particularly in diseases where the pathogenesis is based on healthy endothelial cell proliferation, including hemangiomas.

Propranolol for the treatment of vascular sarcomas

Vascular sarcomas are abnormal proliferations of endothelial cells. They range from benign hemangioma to aggressive angiosarcoma, and are characterized by dysregulated angiogenic signaling. Propranolol is a β-adrenergic receptor inhibitor that has demonstrated clinical efficacy in benign infantile hemangioma, and is now being used experimentally for more aggressive vascular sarcomas and other cancers. In this review, we discuss the use of propranolol in targeting these receptors in vascular tumors and other cancers.

Visualizing Ligand Binding to a GPCR In Vivo Using NanoBRET

The therapeutic action of a drug depends on its ability to engage with its molecular target in vivo. However, current drug discovery strategies quantify drug levels within organs rather than determining the binding of drugs directly to their specific molecular targets in vivo. This is a particular problem for assessing the therapeutic potential of drugs that target malignant tumors where access and binding may be impaired by disrupted vasculature and local hypoxia. Here we have used triple-negative human breast cancer cells expressing β2-adrenoceptors tagged with the bioluminescence protein NanoLuc to provide a bioluminescence resonance energy transfer approach to directly quantify ligand binding to a G protein-coupled receptor in vivo using a mouse model of breast cancer.

Non-selective beta blockers inhibit angiosarcoma cell viability and increase progression free- and overall-survival in patients diagnosed with metastatic angiosarcoma

Patients with metastatic angiosarcoma undergoing chemotherapy, radiation, and/or surgery experience a median progression free survival of less than 6 months and a median overall survival of less than 12 months. Given the aggressive nature of this cancer, angiosarcoma clinical responses to chemotherapy or targeted therapeutics are generally very poor. Inhibition of beta adrenergic receptor (β-AR) signaling has recently been shown to decrease angiosarcoma tumor cell viability, abrogate tumor growth in mouse models, and decrease proliferation rates in preclinical and clinical settings. In the current study we used cell and animal tumor models to show that β-AR antagonism abrogates mitogenic signaling and reduces angiosarcoma tumor cell viability, and these molecular alterations translated into patient tumors. We demonstrated that non-selective β-AR antagonists are superior to selective β-AR antagonists at inhibiting angiosarcoma cell viability. A prospective analysis of non- selective β-AR antagonists in a single arm clinical study of metastatic angiosarcoma patients revealed that incorporation of either propranolol or carvedilol into patients' treatment regimens leads to a median progression free and overall survival of 9 and 36 months, respectively. These data suggest that incorporation of non-selective β-AR antagonists into existing therapies against metastatic angiosarcoma can enhance clinical outcomes.

Use of non-selective β-blockers is associated with decreased tumor proliferative indices in early stage breast cancer

Previous studies suggest beta-adrenergic receptor (β-AR) antagonists (β-blockers) decrease breast cancer progression, tumor metastasis, and patient mortality; however the mechanism for this is unknown. Immunohistochemical analysis of normal and malignant breast tissue revealed overexpression of β1-AR and β3-AR in breast cancer. A retrospective cross-sectional study of 404 breast cancer patients was performed to determine the effect of β-blocker usage on tumor proliferation. Our analysis revealed that non-selective β-blockers, but not selective β-blockers, reduced tumor proliferation by 66% (p < 0.0001) in early stage breast cancer compared to non-users. We tested the efficacy of propranolol on an early stage breast cancer patient, and quantified the tumor proliferative index before and after treatment, revealing a propranolol-mediated 23% reduction (p = 0.02) in Ki67 positive tumor cells over a three-week period. The anti-proliferative effects of β-blockers were measured in a panel of breast cancer lines, demonstrating that mammary epithelial cells were resistant to propranolol, and that most breast cancer cell lines displayed dose dependent viability decreases following treatment. Selective β-blockers alone or in combination were not as effective as propranolol at reducing breast cancer cell proliferation. Molecular analysis revealed that propranolol treatment of the SK-BR-3 breast cancer line, which showed high sensitivity to beta blockade, led to a reduction in Ki67 protein expression, decreased phosphorylation of the mitogenic signaling regulators p44/42 MAPK, p38 MAPK, JNK, and CREB, increased phosphorylation of the cell survival/apoptosis regulators AKT, p53, and GSK3β. In conclusion, use of non-selective β-blockers in patients with early stage breast cancer may lead to decreased tumor proliferation.

Infantile hemangioma: pathogenesis and mechanisms of action of propranolol

Infantile hemangioma (IH) is the most common benign tumor of childhood, with a prevalence of 4 % to 10 %. It is characterized by a proliferative rapid growth phase, which starts after a few weeks of life, followed by a slow regression phase. In IH cases that are potentially disfiguring or life-threatening (10 % to 15 % of all cases), systemic therapy should be promptly initiated. Data source The present study reviews published scientific articles available in reliable electronic databases. Selected were all studies that evaluated the pathogenesis of IH and the mechanisms of action of propranolol. Conclusions The pathogenesis of IH has not been fully elucidated. Studies show that, in the proliferative phase of IH, there is an imbalance of angiogenic factors and an increase in the levels of vascular endothelial growth factor and matrix metalloproteinases 2 and 9. In the regression phase, the levels of these factors decrease, whereas those of antiangiogenic factors, including tissue inhibitors of matrix metalloproteinases, increase. Since 2008, propranolol has become the drug of choice in the treatment of IH, targeting vascular tone, angiogenesis, and apoptosis. Current insights into the pathogenesis of IH allow for the development of new therapeutic strategies.

Beta-adrenergic receptors are expressed across diverse cancers

Based largely on retrospective analyses and a handful of prospective case reports, pharmacological inhibition of the beta adrenergic receptors using beta blockers has shown clinical anti-cancer efficacy in reproductive cancers, as well as angiosarcoma and multiple myeloma. Because of the potential promise of beta blockers as an adjunct to standard anti-cancer therapy, it is imperative to identify other tumor types expressing beta adrenergic (β-AR) receptors so future preclinical and clinical studies can be directed at the most promising tumor targets. We performed immunohistochemical detection of β1-AR, β2-AR, and β3-AR across 29 of the most common human cancer types (389 tissues total) and 19 matching non-diseased controls (100 tissues total). Our analysis revealed all three β-AR receptors were expressed most strongly in melanoma relative to other cancer types. Other malignancies that revealed relatively higher levels of β-AR receptors were esophagus, pancreas, kidney, and lung cancers. Moreover, particular β-AR receptors exhibited significant overexpression in tumor tissue relative to their matching normal tissue in urogenital/reproductive malignancies including breast, endometrium, ovarian, and urothelial cancer, as well as colon, lung, and thyroid cancer. This study identifies several cancer types expressing the β-AR receptors which should be evaluated in future studies for susceptibility to beta blockade.

Early and Late Histological and Ultrastructural Findings in Resected Infantile Capillary Hemangiomas Following Treatment with Topical Beta-Blocker Timolol Maleate 0.5

Background

Infantile capillary hemangiomas (IHs) affect approximately 4-5% of infants. The systemic nonselective β-adrenergic antagonist, propranolol, has become the standard first-line treatment for severe IHs. The topical β-antagonist, timolol maleate, has also demonstrated efficacy and safety in treating superficial and some deep capillary hemangiomas. Despite their therapeutic success and prevalent use, the mechanism of action of β-adrenergic antagonists in the treatment of IHs is not well understood.

Methods

Histopathological and electron microscopic evaluation of two periocular IHs excised at 1 week and 24 months following topical timolol treatment was performed.

Results

Distinct morphological differences were observed between spontaneously regressed and β-antagonist-treated IHs. The former was characterized by diffuse collagen deposition and interstitial fibrosis, while the latter showed organized concentric collagen IV deposition within obliterated vessel lumen, suggestive of waves of endothelial cell apoptosis, leaving behind layers of basement membrane deposits as a stress response.

Conclusions

Based on these observations, we hypothesize that, apart from their well-known cardiac and vasodilatory effects, β-antagonists could induce endothelial cell apoptosis in IH leading to endovascular occlusion and we present supporting evidence to explain why this response might be specific to hypoxic tissue.

Detection of p53 and Bcl-2 expression in cutaneous hemangioma through the quantum dot technique

Hemangioma is one of the most common types of infantile vascular benign tumor. The aim of the present study was to investigate the role of B-cell lymphoma 2 (Bcl-2) and tumor protein p53 (p53) in the proliferation and apoptosis of hemangioma cells. A total of 38 paraffin-embedded hemangioma specimens (16 males and 22 females) and another 5 paraffin-embedded healthy surrounding tissue samples, collected between January 2007 and December 2010, were obtained from the Department of Pathology at Renmin Hospital of Wuhan University (Wuhan, China). Immunohistochemistry, hematoxylin and eosin staining, and quantum dot double staining were used to detect the expression of proliferating cell nuclear antigen (PCNA), Bcl-2 and p53 in hemangioma and healthy surrounding skin tissue samples. All hemangioma specimens were classified into proliferative or the involuting stage hemangioma according to Mulliken's criteria and their expression of PCNA. The results of the quantum dot double staining were analyzed using a multi-spectral imaging system. One-way analysis of the variance and the Student-Newman-Keuls q test were performed to statistically analyze the data. There were 24 cases of proliferative stage and 14 cases of involuting stage hemangioma among the specimens. Immunohistochemical analysis results indicated a high expression of Bcl-2 and p53 in proliferative stage hemangioma tissue samples, and low expression in involuting stage hemangioma and healthy tissue samples. Statistical analysis of the results from quantum dot double staining demonstrated that the expression of Bcl-2 and p53 in proliferative hemangioma was significantly increased compared with that in involuting stage specimens (P<0.05) and healthy tissue samples (P<0.05). No significant difference in Bcl-2 and p53 expression was identified between the involuting hemangioma and healthy surrounding tissue samples. The higher expression of Bcl-2 and p53 in proliferative hemangioma suggests that Bcl-2 may cause an imbalance between endothelial cell proliferation and apoptosis through the inhibition of endothelial cell apoptosis. Furthermore, p53 may promote the proliferation of endothelial cells in proliferative hemangioma.

Disorders of the neonatal nasal cavity: Fundamentals for practice

Neonatal nasal obstruction is a well-known clinical entity. Fortunately, it is rarely life-threatening and usually resolves with conservative management. As with most conditions, a systematic history and thorough physical examination are crucial for correct diagnosis and management. The initial diagnosis may be elusive and require either serial or more in-depth evaluations. Occasionally, examination may reveal structural abnormalities necessitating surgical intervention. Fortunately most of these abnormalities are amenable to surgery; however, a select few are notoriously difficult to treat.

Current trends in medical management of infantile hemangioma

PURPOSE OF REVIEW

Infantile hemangiomas are the most common benign, soft-tissue tumors of infancy, affecting between 5 and 10% of newborns, and up to 30% of premature infants. Morbidity may include disfigurement and scarring, difficulty in feeding, ulceration, vision loss, airway compromise, congestive heart failure, and death. Advances in understanding the pathogenesis of infantile hemangiomas have given rise to a number of promising treatments. This article reviews the current options for medical management of infantile hemangiomas.

RECENT FINDINGS

In the proliferative phase of infantile hemangiomas, vascular endothelial growth factor and basic fibroblast growth factor have shown increased expression, and vascular endothelial growth factor expression has been up-regulated by adrenergic stimulation. Moreover, the role of the renin-angiotensin system in the pathogenesis of infantile hemangiomas has been demonstrated. Numerous medical options have been under investigation. Since 2008, propanolol has become the first-line therapy, whereas other medical treatments are used less frequently or when propanolol is unsuccessful.

SUMMARY

Propranolol has been recently adopted as the first-line medical treatment for complicated infantile hemangiomas. Although emerging treatment options and modalities have shown promising results, there need to be high-quality multicenter randomized trials to support these preliminary data.

Rebound Growth of Infantile Hemangiomas After Propranolol Therapy

BACKGROUND AND OBJECTIVES

Propranolol is first-line therapy for problematic infantile hemangiomas (IHs). Rebound growth after propranolol discontinuation is noted in 19% to 25% of patients. Predictive factors for rebound are not completely understood and may alter the management approach. The goal of the study was to describe a cohort of patients with IHs treated with propranolol and to identify predictors for rebound growth.

METHODS

A multicenter retrospective cohort study was conducted in patients with IHs treated with propranolol. Patient demographic characteristics, IH characteristics, and specifics of propranolol therapy were obtained. Episodes of rebound growth were recorded. Patients' responses to propranolol were evaluated through a visual analog scale.

RESULTS

A total of 997 patients were enrolled. The incidence of rebound growth was 231 of 912 patients (25.3%). Mean age at initial rebound was 17.1 months. The odds of rebound among those who discontinued therapy at <9 months was 2.4 (odds ratio [OR]: 2.4; 95% confidence interval [CI]: 1.3 to 4.5; P = .004) compared with those who discontinued therapy between 12 to 15 months of life. Female gender, location on head and neck, segmental pattern, and deep or mixed skin involvement were associated with rebound on univariate analysis. With multivariate analysis, only deep IHs (OR: 3.3; 95% CI: 1.9 to 6.0; P < .001) and female gender (OR: 1.7; 95% CI: 1.1 to 2.6; P = .03) were associated. Of those with rebound growth, 83% required therapeutic modification including 62% of patients with modifications in their propranolol therapy.

CONCLUSIONS

Rebound growth occurred in 25% of patients, requiring modification of systemic therapy in 15%. Predictive factors for rebound growth included age of discontinuation, deep IH component, and female gender. Patients with these predictive factors may require a prolonged course of therapy.

Cell Therapy in Ischemic Heart Disease: Interventions That Modulate Cardiac Regeneration

The incidence of severe ischemic heart disease caused by coronary obstruction has progressively increased. Alternative forms of treatment have been studied in an attempt to regenerate myocardial tissue, induce angiogenesis, and improve clinical conditions. In this context, cell therapy has emerged as a promising alternative using cells with regenerative potential, focusing on the release of paracrine and autocrine factors that contribute to cell survival, angiogenesis, and tissue remodeling. Evidence of the safety, feasibility, and potential effectiveness of cell therapy has emerged from several clinical trials using different lineages of adult stem cells. The clinical benefit, however, is not yet well established. In this review, we discuss the therapeutic potential of cell therapy in terms of regenerative and angiogenic capacity after myocardial ischemia. In addition, we addressed nonpharmacological interventions that may influence this therapeutic practice, such as diet and physical training. This review brings together current data on pharmacological and nonpharmacological approaches to improve cell homing and cardiac repair.

Propranolol Targets Hemangioma Stem Cells via cAMP and Mitogen-Activated Protein Kinase Regulation

Infantile hemangiomas (IHs) are the most common vascular tumor and arise from a hemangioma stem cell (HemSC). Propranolol has proved efficacious against IHs. A selective β2-adrenergic receptor (AR) antagonist mirrored propranolol’s effects on HemSCs. These results show that propranolol acts on HemSCs in IH to suppress proliferation and promote apoptosis in a dose-dependent fashion via β2AR perturbation.

Infantile hemangiomas (IHs) are the most common vascular tumor and arise from a hemangioma stem cell (HemSC). Propranolol has proved efficacious for problematic IHs. Propranolol is a nonselective β-adrenergic receptor (βAR) antagonist that can lower cAMP levels and activate the mitogen-activated protein kinase (MAPK) pathway downstream of βARs. We found that HemSCs express β1AR and β2AR in proliferating IHs and determined the role of these βARs and the downstream pathways in mediating propranolol’s effects. In isolated HemSCs, propranolol suppressed cAMP levels and activated extracellular signal-regulated kinase (ERK)1/2 in a dose-dependent fashion. Propranolol, used at doses of <10⁻⁴ M, reduced cAMP levels and decreased HemSC proliferation and viability. Propranolol at ≥10⁻⁵ M reduced cAMP levels and activated ERK1/2, and this correlated with HemSC apoptosis and cytotoxicity at ≥10⁻⁴ M. Stimulation with a βAR agonist, isoprenaline, promoted HemSC proliferation and rescued the antiproliferative effects of propranolol, suggesting that propranolol inhibits βAR signaling in HemSCs. Treatment with a cAMP analog or a MAPK inhibitor partially rescued the HemSC cell viability suppressed by propranolol. A selective β2AR antagonist mirrored propranolol’s effects on HemSCs in a dose-dependent fashion, and a selective β1AR antagonist had no effect, supporting a role for β2AR signaling in IH pathobiology. In a mouse model of IH, propranolol reduced the vessel caliber and blood flow assessed by ultrasound Doppler and increased activation of ERK1/2 in IH cells. We have thus demonstrated that propranolol acts on HemSCs in IH to suppress proliferation and promote apoptosis in a dose-dependent fashion via β2AR perturbation, resulting in reduced cAMP and MAPK activation.

Significance

The present study investigated the action of propranolol in infantile hemangiomas (IHs). IHs are the most common vascular tumor in children and have been proposed to arise from a hemangioma stem cell (HemSC). Propranolol, a nonselective β-adrenergic receptor (βAR) antagonist, has proven efficacy; however, understanding of its mechanism of action on HemSCs is limited. The presented data demonstrate that propranolol, via βAR perturbation, dose dependently suppresses cAMP levels and activated extracellular signal-regulated kinase 1/2. Furthermore, propranolol acts via perturbation of β2AR, and not β1AR, although both receptors are expressed in HemSCs. These results provide important insight into propranolol’s action in IHs and can be used to guide the development of more targeted therapy.

Beta Adrenergic Signaling: A Targetable Regulator of Angiosarcoma and Hemangiosarcoma

Human angiosarcomas and canine hemangiosarcomas are highly aggressive cancers thought to arise from cells of vascular origin. The pathological features, morphological organization, and clinical behavior of canine hemangiosarcomas are virtually indistinct from those of human angiosarcomas. Overall survival with current standard-of-care approaches remains dismal for both humans and dogs, and each is likely to succumb to their disease within a short duration. While angiosarcomas in humans are extremely rare, limiting their study and treatment options, canine hemangiosarcomas occur frequently. Therefore, studies of these sarcomas in dogs can be used to advance treatment approaches for both patient groups. Emerging data suggest that angiosarcomas and hemangiosarcomas utilize beta adrenergic signaling to drive their progression by regulating the tumor cell niche and fine-tuning cellular responses within the tumor microenvironment. These discoveries indicate that inhibition of beta adrenergic signaling could serve as an Achilles heel for these tumors and emphasize the need to design therapeutic strategies that target tumor cell and stromal cell constituents. In this review, we summarize recent discoveries and present new hypotheses regarding the roles of beta adrenergic signaling in angiosarcomas and hemangiosarcomas. Because the use of beta adrenergic receptor antagonists is well established in human and veterinary medicine, beta blockade could provide an immediate adjunct therapy for treatment along with a tangible opportunity to improve upon the outcomes of both humans and dogs with these diseases.

Glucose transporter 1-positive endothelial cells in infantile hemangioma exhibit features of facultative stem cells

Endothelial glucose transporter 1 (GLUT1) is a definitive and diagnostic marker for infantile hemangioma (IH), a vascular tumor of infancy. To date, GLUT1-positive endothelial cells in IH have not been quantified nor directly isolated and studied. We isolated GLUT1-positive and GLUT1-negative endothelial cells from IH specimens and characterized their proliferation, differentiation, and response to propranolol, a first-line therapy for IH, and to rapamycin, an mTOR pathway inhibitor used to treat an increasingly wide array of proliferative disorders. Although freshly isolated GLUT1-positive cells, selected using anti-GLUT1 magnetic beads, expressed endothelial markers CD31, VE-Cadherin, and vascular endothelial growth factor receptor 2, they converted to a mesenchymal phenotype after 3 weeks in culture. In contrast, GLUT1-negative endothelial cells exhibited a stable endothelial phenotype in vitro. GLUT1-selected cells were clonogenic when plated as single cells and could be induced to redifferentiate into endothelial cells, or into pericytes/smooth muscle cells or into adipocytes, indicating a stem cell-like phenotype. These data demonstrate that, although they appear and function in the tumor as bona fide endothelial cells, the GLUT1-positive endothelial cells display properties of facultative stem cells. Pretreatment with rapamycin for 4 days significantly slowed proliferation of GLUT1-selected cells, whereas propranolol pretreatment had no effect. These results reveal for the first time the facultative nature of GLUT1-positive endothelial cells in IH.

Propranolol induces regression of hemangioma cells via the down-regulation of the PI3K/Akt/eNOS/VEGF pathway

BACKGROUND

Infantile hemangioma (IH) is a benign vascular neoplasm resulting from the abnormal proliferation of endothelial cells and pericytes in infants. Propranolol, a non-selective β-adrenergic blocker, has recently emerged as an effective therapy for IH, causing regression. However, its potential therapeutic mechanism remains largely unknown.

PROCEDURE

An XPTS-1 cell line was established by isolating hemangioma-derived endothelial cells (HemECs) from a specimen of human proliferating IH. Flow cytometer assay was performed to assess the effect of propranolol on cell cycle distribution. Western blot was employed to determine changes of protein expression. Matrigel invasion and tube formation assays were used to measure invasion ability and tube formation ability, respectively. Commercial kits were employed to quantify NO and VEGF levels.

RESULTS

Propranolol blocked norepinephrine-induced HemECs cell cycle progression as well as the expression of cyclin A2 and cyclin D2; whereas p21 and p27 proteins were altered conversely. Propranolol inhibited norepinephrine-induced cell invasion by reducing the expression of MMP-9, VEGF, and p-cofilin. NO and VEGF release induced by norepinephrine was decreased by propranolol pretreatment, coincident with alterations in the phosphorylation of Akt, eNOS, and VEGFR-2. Tube formation ability and subsequent levels of NO and VEGF elevated by norepinephrine were distinctively counteracted in HemECs.

CONCLUSIONS

The current study demonstrated the antiangiogenic properties of propranolol in vitro and that the drug was able to induce the regression of hemangioma cells via the inhibition of cell cycle progression, invasion, and tube formation, concomitantly with decreased NO and VEGF levels through the down-regulation of the PI3K/Akt/eNOS/VEGF pathway.

Neural Regulation of Pancreatic Cancer: A Novel Target for Intervention

The tumor microenvironment is known to play a pivotal role in driving cancer progression and governing response to therapy. This is of significance in pancreatic cancer where the unique pancreatic tumor microenvironment, characterized by its pronounced desmoplasia and fibrosis, drives early stages of tumor progression and dissemination, and contributes to its associated low survival rates. Several molecular factors that regulate interactions between pancreatic tumors and their surrounding stroma are beginning to be identified. Yet broader physiological factors that influence these interactions remain unclear. Here, we discuss a series of preclinical and mechanistic studies that highlight the important role chronic stress plays as a physiological regulator of neural-tumor interactions in driving the progression of pancreatic cancer. These studies propose several approaches to target stress signaling via the β-adrenergic signaling pathway in order to slow pancreatic tumor growth and metastasis. They also provide evidence to support the use of β-blockers as a novel therapeutic intervention to complement current clinical strategies to improve cancer outcome in patients with pancreatic cancer.

Mechanisms of propranolol action in infantile hemangioma

Infantile hemangioma is a common tumor of infancy. Although most hemangiomas spontaneously regress, treatment is indicated based on complications, risk to organ development and function, and disfigurement. The serendipitous discovery of propranolol, a non-selective β-adrenergic receptor blocker, as an effective means to regress hemangiomas has made this a first-line therapy for hemangioma patients. Propranolol has shown remarkable response rates. There are, however, some adverse effects, which include changes in sleep, acrocyanosis, hypotension, and hypoglycemia. Over the last few years, researchers have focused on understanding the mechanisms by which propranolol causes hemangioma regression. This has entailed study of cultured vascular endothelial cells including endothelial cells isolated from hemangioma patients. In this article, we review recent studies offering potential mechanisms of how various cell types found in hemangioma may respond to propranolol.

Infantile hemangiomas, retinopathy of prematurity and cancer: a common pathogenetic role of the β-adrenergic system

The serendipitous demonstration that the nonselective β-adrenergic receptor (β-AR) antagonist propranolol promotes the regression of infantile hemangiomas (IHs) aroused interest around the involvement of the β-adrenergic system in angiogenic processes. The efficacy of propranolol was related to the β2-AR blockade and the consequent inhibition of the production of vascular endothelial growth factor (VEGF), suggesting the hypothesis that propranolol could also be effective in treating retinopathy of prematurity (ROP), a retinal pathology characterized by VEGF-induced neoangiogenesis. Consequent to the encouraging animal studies, a pilot clinical trial showed that oral propranolol protects newborns from ROP progression, even though this treatment is not sufficiently safe. Further, animal studies clarified the role of β3-ARs in the development of ROP and, together with several preclinical studies demonstrating the key role of the β-adrenergic system in tumor progression, vascularization, and metastasis, prompted us to also investigate the participation of β3-ARs in tumor growth. The aim of this review is to gather the recent findings on the role of the β-adrenergic system in IHs, ROP, and cancer, highlighting the fact that these different pathologies, triggered by different pathogenic noxae, share common pathogenic mechanisms characterized by the presence of hypoxia-induced angiogenesis, which may be contrasted by targeting the β-adrenergic system. The mechanisms characterizing the pathogenesis of IHs, ROP, and cancer may also be active during the fetal-neonatal development, and a great contribution to the knowledge on the role of β-ARs in diseases characterized by chronic hypoxia may come from research focusing on the fetal and neonatal period.

The use of propranolol in the treatment of infantile haemangiomas: an update on potential mechanisms of action

Currently, propranolol is the preferred treatment for problematic proliferating infantile haemangiomas (IHs). The rapid action of propranolol has been shown to be especially dramatic in IHs involving dyspnoea, haemodynamic compromise, palpebral occlusion or ulceration. Another remarkable aspect of propranolol treatment revealed that the growth of the IHs was not only stabilized, but also that the improvement continued until complete involution was achieved, leading to a considerable shortening of the natural course of IH. However, the mechanisms underlying the effects of propranolol have not been fully elucidated. Recent studies have offered evidence of a variety of mechanisms. These include the promotion of pericyte-mediated vasoconstriction, the inhibition of vasculogenesis and catecholamine-induced angiogenesis, the disruption of haemodynamic force-induced cell survival, and the inactivation of the renin-angiotensin system. This review summarizes these mechanisms and the new concepts that are emerging in this area of research. Moreover, several molecular mechanisms by which propranolol may modify neovascularization in IH have also been proposed. The antihaemangioma effect of propranolol may not be attributable to a single mechanism, but rather to a combination of events that have not yet been elucidated or understood. Further studies are needed to evaluate and verify these mechanisms to gain a greater understanding of the effects of the intake of propranolol on haemangioma involution.