Catecholamines facilitate VEGF-dependent angiogenesis via ß2-adrenoceptor-induced Epac1 and PKA activation.

Chronic stress has been associated with the progression of cancer and antagonists for ß-adrenoceptors (ßAR) are regarded as therapeutic option. As they are also used to treat hemangiomas as well as retinopathy of prematurity, a role of endothelial ß2AR in angiogenesis can be envisioned. We therefore investigated the role of ß2AR-induced cAMP formation by analyzing the role of the cAMP effector molecules exchange factor directly activated by cAMP 1 (Epac1) and protein kinase A (PKA) in endothelial cells (EC). Epac1-deficient mice showed a reduced amount of pre-retinal neovascularizations in the model of oxygen-induced retinopathy, which is predominantly driven by vascular endothelial growth factor (VEGF). siRNA-mediated knockdown of Epac1 in human umbilical vein EC (HUVEC) decreased angiogenic sprouting by lowering the expression of the endothelial VEGF-receptor-2 (VEGFR-2). Conversely, Epac1 activation by ß2AR stimulation or the Epac-selective activator cAMP analog 8-p-CPT-2'-O-Me-cAMP (8-pCPT) increased VEGFR-2 levels and VEGF-dependent sprouting. Similar to Epac1 knockdown, depletion of the monomeric GTPase Rac1 decreased VEGFR-2 expression. As Epac1 stimulation induces Rac1 activation, Epac1 might regulate VEGFR-2 expression through Rac1. In addition, we found that PKA was also involved in the regulation of angiogenesis in EC since the adenylyl cyclase (AC) activator forskolin (Fsk), but not 8-pCPT, increased sprouting in Epac1-depleted HUVEC and this increase was sensitive to a selective synthetic peptide PKA inhibitor. In accordance, ß2AR- and AC-activation, but not Epac1 stimulation increased VEGF secretion in HUVEC.Our data indicate that high levels of catecholamines, which occur during chronic stress, prime the endothelium for angiogenesis through a ß2AR-mediated increase in endothelial VEGFR-2 expression and VEGF secretion.

Epac1 links prostaglandin E2 to ß-catenin-dependent transcription during epithelial-to-mesenchymal transition.

In epithelial cells, ß-catenin is localized at cell-cell junctions where it stabilizes adherens junctions. When these junctions are disrupted, ß-catenin can translocate to the nucleus where it functions as a transcriptional cofactor. Recent research has indicated that PGE2 enhances the nuclear function of ß-catenin through cyclic AMP. Here, we aim to study the role of the cyclic AMP effector Epac in ß-catenin activation by PGE2 in non-small cell lung carcinoma cells. We show that PGE2 induces a down-regulation of E-cadherin, promotes cell migration and enhances ß-catenin translocation to the nucleus. This results in ß-catenin-dependent gene transcription. We also observed increased expression of Epac1. Inhibition of Epac1 activity using the CE3F4 compound or Epac1 siRNA abolished the effects of PGE2 on ß-catenin. Further, we observed that Epac1 and ß-catenin associate together. Expression of an Epac1 mutant with a deletion in the nuclear pore localization sequence prevents this association. Furthermore, the scaffold protein Ezrin was shown to be required to link Epac1 to ß-catenin. This study indicates a novel role for Epac1 in PGE2-induced EMT and subsequent activation of ß-catenin.

TGF-ß-induced profibrotic signaling is regulated in part by the WNT receptor Frizzled-8.

TGF-ß is important in lung injury and remodeling processes. TGF-ß and Wingless/integrase-1 (WNT) signaling are interconnected; however, the WNT ligand-receptor complexes involved are unknown. Thus, we aimed to identify Frizzled (FZD) receptors that mediate TGF-ß-induced profibrotic signaling. MRC-5 and primary human lung fibroblasts were stimulated with TGF-ß1, WNT-5A, or WNT-5B in the presence and absence of specific pathway inhibitors. Specific small interfering RNA was used to knock down FZD8. In vivo studies using bleomycin-induced lung fibrosis were performed in wild-type and FZD8-deficient mice. TGF-ß1 induced FZD8 specifically via Smad3-dependent signaling in MRC-5 and primary human lung fibroblasts. It is noteworthy that FZD8 knockdown reduced TGF-ß1-induced collagen Iα1, fibronectin, versican, α-smooth muscle (sm)-actin, and connective tissue growth factor. Moreover, bleomycin-induced lung fibrosis was attenuated in FZD8-deficient mice in vivo Although inhibition of canonical WNT signaling did not affect TGF-ß1-induced gene expression in vitro, noncanonical WNT-5B mimicked TGF-ß1-induced fibroblast activation. FZD8 knockdown reduced both WNT-5B-induced gene expression of fibronectin and α-sm-actin, as well as WNT-5B-induced changes in cellular impedance. Collectively, our findings demonstrate a role for FZD8 in TGF-ß-induced profibrotic signaling and imply that WNT-5B may be the ligand for FZD8 in these responses.-Spanjer, A. I. R., Baarsma, H. A., Oostenbrink, L. M., Jansen, S. R., Kuipers, C. C., Lindner, M., Postma, D. S., Meurs, H., Heijink, I. H., Gosens, R., Königshoff, M. TGF-ß-induced profibrotic signaling is regulated in part by the WNT receptor Frizzled-8.

Prostaglandin E2 promotes MYCN non-amplified neuroblastoma cell survival via ß-catenin stabilization.

Amplification of MYCN is the most well-known prognostic marker of neuroblastoma risk classification, but still is only observed in 25% of cases. Recent evidence points to the cyclic adenosine monophosphate (cAMP) elevating ligand prostaglandin E2 (PGE2 ) and ß-catenin as two novel players in neuroblastoma. Here, we aimed to define the potential role of PGE2 and cAMP and its potential interplay with ß-catenin, both of which may converge on neuroblastoma cell behaviour. Gain and loss of ß-catenin function, PGE2 , the adenylyl cyclase activator forskolin and pharmacological inhibition of cyclooxygenase-2 (COX-2) were studied in two human neuroblastoma cell lines without MYCN amplification. Our findings show that PGE2 enhanced cell viability through the EP4 receptor and cAMP elevation, whereas COX-2 inhibitors attenuated cell viability. Interestingly, PGE2 and forskolin promoted glycogen synthase kinase 3ß inhibition, ß-catenin phosphorylation at the protein kinase A target residue ser675, ß-catenin nuclear translocation and TCF-dependent gene transcription. Ectopic expression of a degradation-resistant ß-catenin mutant enhances neuroblastoma cell viability and inhibition of ß-catenin with XAV939 prevented PGE2 -induced cell viability. Finally, we show increased ß-catenin expression in human high-risk neuroblastoma tissue without MYCN amplification. Our data indicate that PGE2 enhances neuroblastoma cell viability, a process which may involve cAMP-mediated ß-catenin stabilization, and suggest that this pathway is of relevance to high-risk neuroblastoma without MYCN amplification.

Videodensitometric time-density curve change after alcohol septal ablation of obstructive hypertrophic cardiomyopathy.

A recently developed computerized method for estimation of myocardial perfusion, based on the analysis of the time-density curves, is demonstrated to assess myocardial blush over a selected myocardial region of interest in a patient with obstructive hypertrophic cardiomyopathy before and after alcohol septal ablation.

{beta}-Catenin regulates airway smooth muscle contraction.

beta-Catenin is an 88-kDa member of the armadillo family of proteins that is associated with the cadherin-catenin complex in the plasma membrane. This complex interacts dynamically with the actin cytoskeleton to stabilize adherens junctions, which play a central role in force transmission by smooth muscle cells. Therefore, in the present study, we hypothesized a role for beta-catenin in the regulation of smooth muscle force production. beta-Catenin colocalized with smooth muscle alpha-actin (sm-alpha-actin) and N-cadherin in plasma membrane fractions and coimmunoprecipitated with sm-alpha-actin and N-cadherin in lysates of bovine tracheal smooth muscle (BTSM) strips. Moreover, immunocytochemistry of cultured BTSM cells revealed clear and specific colocalization of sm-alpha-actin and beta-catenin at the sites of cell-cell contact. Treatment of BTSM strips with the pharmacological beta-catenin/T cell factor-4 (TCF4) inhibitor PKF115-584 (100 nM) reduced beta-catenin expression in BTSM whole tissue lysates and in plasma membrane fractions and reduced maximal KCl- and methacholine-induced force production. These changes in force production were not accompanied by changes in the expression of sm-alpha-actin or sm-myosin heavy chain (MHC). Likewise, small interfering RNA (siRNA) knockdown of beta-catenin in BTSM strips reduced beta-catenin expression and attenuated maximal KCl- and methacholine-induced contractions without affecting sm-alpha-actin or sm-MHC expression. Conversely, pharmacological (SB-216763, LiCl) or insulin-induced inhibition of glycogen synthase kinase-3 (GSK-3) enhanced the expression of beta-catenin and augmented maximal KCl- and methacholine-induced contractions. We conclude that beta-catenin is a plasma membrane-associated protein in airway smooth muscle that regulates active tension development, presumably by stabilizing cell-cell contacts and thereby supporting force transmission between neighboring cells.

[Molecular genetics of the long QT syndrome: clinical aspects]. / A hosszú QT-szindróma molekuláris genetikája: klinikai vonatkozások.

The long QT syndrome (LQTS) is a heart disorder which is characterised by the prolongation of the QT interval of the surface electrocardiogram and is associated with malignant arrhythmias, syncopal episodes, torsade de pointes form ventricular tachycardias and an increased risk of sudden cardiac death. There are two familial forms of LQTS, the autosomal dominant Romano-Ward syndrome and the autosomal recessive Jervell-Lange-Nielsen syndrome which is associated with congenital senzorineural deaf-mutism. Recent advances in molecular genetics have allowed to identify mutations in four genes, KvLQT1 (11p15.5), HERG (7q35), SCN5A (3p21) and minK (21q22), which cause LQTS. There is a fifth genetic locus known on chromosome 4 (4q25-27), where the disease causing gene has not been identified yet. As LQTS genes code proteins which form sodium and potassium channels of the heart, LQTS can be regarded as the disease of cardiac ion channels. The KvLQT1 and minK genes code the slowly activating, delayed rectifier (Iks) potassium channel, the HERG gene code the rapidly activating, delayed rectifier (Ikr) potassium channel of the heart, while the SCN5A gene codes a cardiac sodium channel. Mutations in KvLQT1, minK and HERG genes affects repolarising, rectifier potassium currents, while SCN5A mutations cause delayed inactivation and reopening of the cardiac sodium channel, which initiates the depolarisation of cardiac cells. Both alterations result in a prolongation of cardiac repolarisation which is represented in the elongation of the QT interval. Elucidation of the genetic base of the disease provided new tools in the clinical management of LQTS. It has been shown that changes in the repolarisation parameters on the ECG may be predictive for the causative gene and different LQTS genes are associated with different clinical picture. More importantly, it is possible to use "gene-specific" therapy in LQTS which specifically targets ion channels affected by given gene mutations.

[Clinical and molecular genetics of hypertrophic cardiomyopathy]. / A hypertrophiás cardiomyopathia klinikai és molekuláris genetikája.

Recent developments in molecular genetics have allowed to identify mutations in seven genes coding the beta myosin heavy chain, troponin T, alpha tropomyosin, myosin binding protein C, essential and regulatory myosin light chains and troponin I causing hypertrophic cardiomyopathy. These mutations affect critical, evolutionary conserved nucleotides of these genes and influence vital functions of the encoded proteins. As all seven genes encodes sarcomeric proteins in the heart muscle, hypertrophic cardiomyopathy is regarded these days as a disease of the sarcomer. Recent data indicate that some mutations are associated with "malignant" clinical picture, with rapidly developing, severe symptoms of the disease and increased risk of sudden cardiac death while other mutations bear a more favourable prognosis. Apart of the disease causing mutation other factors, including disease modifier genes, are likely to make an impact on the clinical appearance of hypertrophic cardiomyopathy. The knowledge provided by molecular genetics influences the clinical management of the disease even today and based on the investigation of mutation carrying patients new diagnostic criteria was proposed for hypertrophic cardiomyopathy. The challenge for the future is the establishment of routine genetic diagnostics and the development of possible gene therapy.

Altered patterns of cardiac intercellular junction distribution in hypertrophic cardiomyopathy.

OBJECTIVE: To examine the distribution pattern of intercellular junctions (the mechanically coupling desmosomes and the electrically coupling gap junctions) in hypertrophic cardiomyopathy (HCM) hearts showing myofibre disarray. DESIGN: Samples from six necropsied hearts were studied, representing the interventricular septum and the free walls of the left and right ventricles. Immunohistochemical labelling of desmoplakin was used as a marker for desmosomes, and of connexin43 as a marker for gap junctions, in single and double stainings. The slides were examined by confocal laser scanning microscopy. RESULTS: Marked disorganisation of intercalated discs was observed in areas featuring myofibre disarray. Besides overall derangement, localised abnormalities in desmosome organisation were evident, which included: (1) the formation of abnormally enlarged megadiscs; (2) the presence of intersecting disc structures; and (3) aberrant side to side desmosomal connections. Gap junctional abnormalities included: (1) random distribution of gap junctions over the surface of myocytes, rather than localisation to intercalated discs; (2) abundant side to side gap junction connections between adjacent myocytes; and (3) formation of abnormally shaped gap junctions. Circles of myocytes continuously interconnected by gap junctions were also observed. Regions of the diseased hearts lacking myofibre disarray, and control hearts of normal patients and patients with other cardiac diseases, did not show these alterations. CONCLUSIONS: The disorganisation of the intercellular junctions associated with myofibre disarray in HCM may play an important role in the pathophysiological manifestations of the disease. The remodelling of gap junction distribution may underlie the formation of an arrhythmogenic substrate, thereby contributing to the generation and maintenance of cardiac arrhythmias associated with HCM.

Human papillomavirus not found in squamous and large cell lung carcinomas by polymerase chain reaction.

BACKGROUND: Human papillomavirus (HPV) has been identified not only in anogenital carcinomas, but also in malignancies of other organs, including bronchogenic carcinomas. Previous studies reporting detection of these viruses in lung cancers used mainly in situ hybridization. The authors applied the polymerase chain reaction (PCR) for investigating the occurrence of HPV in bronchial neoplasms. METHODS: Formalin fixed, paraffin embedded tissues of 40 squamous and 7 large cell lung cancers were examined. PCR was done with consensus primers, capable of detecting HPV 6, 11, 16, 18, 31, 33, 52b, and 58. RESULTS: None of the 47 samples contained any of the examined HPV types. CONCLUSIONS: Because the squamous and large cell cancer cases were found not to be associated with HPV infection, this study does not support the potential role of these viruses in the development of lung cancers.

Rapid techniques for DNA extraction from routinely processed archival tissue for use in PCR.

AIMS: To evaluate the ability of four rapid DNA extraction methods to provide DNA for the polymerase chain reaction (PCR) from routinely fixed, paraffin wax embedded archival tissues. METHODS: Eighteen blocks of various tissues, 18 blocks of cervical cancer specimens, and nine blocks of B cell lymphomas were investigated. Both normal and biopsy specimen sized tissues were studied. DNA was extracted using four methods: boiling for 20 minutes in distilled water; boiling for 20 minutes in 5% Chelex-100 resin solution; 3-hour proteinase K digestion; and 3-hour proteinase K digestion, followed by boiling in 5% Chelex-100. Different exons of the p53 gene, human papillomavirus type 16 (HPV 16) sequence, and immunoglobulin heavy chain (IgH) gene rearrangement were amplified from the extracts. RESULTS: The Chelex boiling, proteinase K digestion, and proteinase K digestion-Chelex boiling methods produced DNA suitable for amplification in all of the 45 samples. Boiling in water yielded insufficient template for the PCR in three of the 45 cases (7%), and in six of 42 positive cases (14%) much fainter bands were observed, mostly when the processed material was either biopsy specimen sized or a B cell lymphoma sample. Fragments of the p53 gene were successfully amplified up to 408 base pairs in water boiled extracts, up to 647 in Chelex boiled preparates, and up to 984 in proteinase K digested and proteinase K digested-Chelex boiled samples, although with decreased sensitivity in the last case. All of the templates were reusable after 3 months of storage at -20 degrees C. CONCLUSIONS: Chelex boiling, proteinase K digestion, and proteinase K digestion followed by Chelex boiling produce suitable templates for the PCR from a large variety of paraffin wax embedded tissues. As the simple 20 minute boiling method in 5% Chelex-100 solution requires minimal manipulation and time, it could be useful, especially in the routine processing of large amounts of material.

Nucleolar organizer regions in human maxillary sinus squamous cell carcinoma.

A silver colloid technique for nucleolar organizer regions (AgNOR) was applied to paraffin sections of maxillary sinus squamous cell carcinomas (MSSCC) of 25 patients. The patients were divided into two groups, one with MSSCC recurring in the primary lesion after treatment with radiotherapy, chemotherapy and/or surgery and one without recurrence. Notable differences between the numbers of NOR in neoplastic epithelia and the normal mucosa were observed (P = 0.0001), but there were no differences between the numbers of NOR in the recurrent and non-recurrent carcinomas. This investigation found no prognostic importance in the number of AgNOR in MSSCC.