Gene-expression profiling of endomyocardial biopsies from dogs with dilated cardiomyopathy phenotype

INTRODUCTION

The employment of advanced molecular biology technologies has expanded the diagnostic investigation of cardiomyopathies in dogs; these technologies have predominantly been performed on postmortem samples, although the recent use of endomyocardial biopsy in living dogs has enabled a better premortem diagnostic approach to study the myocardial injury.

ANIMALS, MATERIALS, AND METHODS

Endomyocardial biopsies were collected in nine dogs with a dilated cardiomyopathy phenotype (DCM-p) and congestive heart failure and submitted to histologic examination, next-generation sequencing (NGS), and polymerase chain reaction analysis. Data from three healthy dogs (Fastq files) were retrieved from a previously approved study and used as a control group for ribonucleic acid sequencing.

RESULTS

Histologic examination revealed endocardial fibrosis in 6 of 9 dogs, whereas lymphocytic interstitial infiltrates were detected in 2 of 9 dogs, and lymphoplasmacytic and macrophage infiltrates were detected in 1 of 9 dogs. On polymerase chain reaction analysis, two dogs tested positive for canine parvovirus 2 and one dog for canine distemper virus. Gene-expression pathways involved in cellular energy metabolism (especially carbohydrates-insulin) and cardiac structural proteins were different in all DCM-p dogs compared to those in the control group. When dogs with lymphocytic interstitial infiltrates were compared to those in the control group, NGS analysis revealed the predominant role of genes related to inflammation and pathogen infection.

CONCLUSIONS

NGS technology performed on in vivo endomyocardial biopsies has identified different molecular and genetic factors that could play a role in the development and/or progression of DCM-p in dogs.

ABCA1, TCF7, NFATC1, PRKCZ and PDGFA DNA methylation as potential epigenetic-sensitive targets in acute coronary syndrome via network analysis

Background

Acute coronary syndrome (ACS) is the most severe clinical manifestation of coronary heart disease and the leading cause of death worldwide.

Purpose

To perform an epigenome-wide analysis in circulating CD4+ and CD8+ T cells of ACS patients and healthy subjects (HS) enrolled in the DIANA clinical trial (NCT04371809) in order to identify differentially methylated genes (DMGs).

Methods

Genomic DNA was extracted from CD4+ and CD8+ T cells of all subjects and sequenced by the reduced representation bisulfite sequencing (RRBS) platform. Functional pathway analysis was performed and significant DMGs were selected for gene expression validation by qRT-PCR in ACS patients and HS. GeneMANIA was used to built a prediction gene network. Correlation analyses between molecular data and clinical variables were performed.

Results

In CD4+ T cells we identified 61 differentially methylated regions (DMRs) associated to 57 annotated genes of which 53% (n=32) were hyper- and 47% (n=29) were hypo-methylated in ACS patients vs HS. In CD8+ T cells we identified 613 DMRs associated to 569 annotated genes of which 28% (n=173) were hyper- and 72% (n=440) were hypo-methylated between two groups. In both cell type of ACS patients, 175 DMRs were associated to 157 annotated genes of which 41% (n=72) were hyper- and 59% (n=103) were hypo-methylated. From functional analysis, we selected the top 5 DMGs in the prevalent pathways with the highest differential of methylation values. Specifically, we considered 6 hub genes: NFATC1, TCF7, PDGFA, PRKCB, PRKCZ and ABCA1 and determined their respective expression levels by q-RT-PCR. We found a significant up-regulation of the selected genes in ACS patients vs HS (P<0.001 for all comparisons). Correlation analysis showed both common and cell specific correlation patterns. In CD4+ T cells, PDGFA promoter methylation was negatively correlated with CK-MB concentrations (r=−0.79, P=0.018). ABCA1, TCF7, PDGFA and PRKCZ gene expression was positively associated to CK-MB concentrations (r=0.75, P=0.03; r=0.760, P=0.029; r=0.72, P=0.044; r=0.74, P=0.035, respectively).

Conlusions

This study is the first single-base resolution map of DNA methylome by RRBS in CD4+ and CD8+ T cells, providing specific methylation signatures that could help to clarify the role of aberrant methylation in ACS pathogenesis, and provide the basis for the search of novel epigenetic-sensitive biomarkers in the prevention and early diagnosis of this pathology.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Italian Ministry of Health;Italian Ministry of Research and University

Fetal cardiac growth is associated with in utero gut colonization

BACKGROUND AND AIMS

Intra-uterine metabolic environment predicts newborns' cardiac morphology, metabolism and future health. In adults, gut microbiota composition relates to altered cardiac structure and metabolism. We investigated the relationship between gut microbiota colonization and fetal cardiac growth.

METHODS AND RESULTS

Bacterial composition in meconium samples of 26 healthy, full-term newborns was assessed by 16S rDNA gene sequencing. Its relationship with birth echocardiographic parameters, and the interaction with cord blood levels of inflammatory markers were investigated. Correlative and cluster analysis, linear discriminant analysis effect size and predictive functional analysis based on Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were applied. Fetal left ventricle growth was related to gut microbiota composition at birth. Specifically, left ventricle posterior wall thickness (LVPW) greater than 4 mm was associated with lower microbiota beta and alpha diversity, depletion (LDA score > 3) of several bacteria at each taxonomic level, including Lactobacillales, and enrichment (LDA score > 5) in Enterobacteriales and Enterobacteriaceae. The latter was significantly related to cord blood gamma-glutamyltransferase levels (r = 0.58, p = 0.0057). Functionally, a thicker LVPW was related to up-regulation of pathways involved in lipopolysaccharide biosynthesis (+50%, p = 0.045 in correlative analysis) and energy metabolism (+12%, p = 0.028), and down-regulation of pathways involved in xenobiotic biodegradation (-21 to -53%, p = 0.0063-0.039), PPAR signaling (-24%, p = 0.021) and cardiac muscle contraction (-100%, p = 0.049).

CONCLUSION

Fetal cardiac growth and gut colonization are associated. Greater neonatal LVPW thickness is related to lower diversity of the gut microbiota community, depletion of bacteria having anti-remodeling effects, and enrichment in bacteria functionally linked to inflammation.

Quantitative Real-Time RT-PCR Analysis of Eight Novel Estrogen-Regulated Genes in Breast Cancer

Background

Biological markers capable of predicting the risk of recurrence and the response to treatment in breast cancer are eagerly awaited. Estrogen and progesterone receptors (ER, PgR) in tumor cells mark cancers that are more likely to respond to endocrine treatment, but up to 40% of such patients do not respond. Here, the expression of a group of estrogen-regulated genes, previously identified by microarray analysis of in vitro models, was measured in breast tumors and possible associations with other clinicopathological variables were investigated.

Methods

The expression of CD24, CD44, HAT-1, BAK-1, G1P3, TIEG, NRP-1 and RXRα was measured by quantitative real-time RT-PCR on RNA from eighteen primary breast tumors. Statistical analyses were used to identify correlations among the eight genes and the available clinicopathological data.

Results

Variable expression levels of all the genes were observed in all the samples examined. Significant associations of CD24 with tumor size, CD44 with lymph node invasion, and HAT-1 and BAK-1 with ER positivity were found. The possible combinatorial value of these genes was assessed. Unsupervised hierarchical clustering analysis demonstrated that the expression profile of these genes was able to predict ER status with an acceptable approximation.

Conclusions

Eight novel potential markers for breast cancer have been preliminarily characterized. As expected from in vitro data, their expression is able to discriminate ER- versus ER+ tumors.

Exploiting a new strategy to induce immunogenic cell death to improve dendritic cell-based vaccines for lymphoma immunotherapy

Although promising, the clinical benefit provided by dendritic cell (DC)-based vaccines is still limited and the choice of the optimal antigen formulation is still an unresolved issue. We have developed a new DC-based vaccination protocol for aggressive and/or refractory lymphomas which combines the unique features of interferon-conditioned DC (IFN-DC) with highly immunogenic tumor cell lysates (TCL) obtained from lymphoma cells undergoing immunogenic cell death. We show that treatment of mantle cell lymphoma (MCL) and diffuse large B-cell lymphoma (DLBCL) cell lines with 9-cis-retinoic acid and IFNα (RA/IFNα) induces early membrane exposure of Calreticulin, HSP70 and 90 together with CD47 down-regulation and enhanced HMGB1 secretion. Consistently, RA/IFNα-treated apoptotic cells and -TCLs were more efficiently phagocytosed by DCs compared to controls. Notably, cytotoxic T cells (CTLs) generated with autologous DCs pulsed with RA/IFNα-TCLs more efficiently recognized and specifically lysed MCL or DLBCL cells or targets loaded with several HLA-A*0201 cyclin D1 or HLA-B*0801 survivin epitopes. These cultures also showed an expansion of Th1 and Th17 cells and an increased Th17/Treg ratio. Moreover, DCs loaded with RA/IFNα-TCLs showed enhanced functional maturation and activation. NOD/SCID mice reconstituted with human peripheral blood lymphocytes and vaccinated with autologous RA/IFNα-TCL loaded-IFN-DCs showed lymphoma-specific T-cell responses and a significant decrease in tumor growth with respect to mice treated with IFN-DC unpulsed or loaded with untreated TCLs. This study demonstrates the feasibility and efficacy of the use of RA/IFNα to generate a highly immunogenic TCL as a suitable tumor antigen formulation for the development of effective anticancer DC-based vaccines.

Abstract P1-03-06: Leptin as a mediator of tumor-stromal interactions promotes breast cancer stem cell activity

Breast cancer stem cells (BCSCs) play crucial roles in tumor initiation, metastasis and resistance to anticancer therapies. These cells rely for their properties on complex interactions with the tumor microenvironment through networks of cytokines and growth factors. In this study, we investigated how leptin, as a mediator of tumor-stromal interactions, may affect BCSC activity using breast cancer cell lines and patient-derived samples. We found that conditioned media (CM) from cancer associated fibroblasts and breast adipocytes significantly increase mammosphere formation in breast cancer cells. Depletion of leptin from stromal cell-CM as well as inhibition of leptin signaling by using a full leptin receptor antagonist peptide LDFI completely abrogated this effect. Accordingly, mammosphere cultures exhibited increased leptin receptor expression and leptin exposure enhanced mammosphere formation. Microarray analyses revealed a similar expression profile of genes involved in stem cell biology in mammosphere cells treated with stromal cell-CM and leptin. Interestingly, leptin is able to increase the mammosphere formation in metastatic breast cancer cells isolated from patients (n = 10) and this can be blocked by using peptide LDFI. In addition, leptin receptor (OBR) mRNA expression, analyzed in cells from metastatic fluids, directly correlated with mammosphere formation activity ex vivo (r=0.68, p= 0.05; n = 8). Finally, Kaplan–Meier survival curves indicated that OBR expression correlated with reduced overall survival in breast carcinomas (HR=1.9, p=0.022). Together, our results suggest that leptin/leptin receptor may represent a potential therapeutic target that can block the stromal-tumor interactions that drive BCSC-mediated disease progression.

Citation Format: Giordano C, Panza S, Chemi F, Barone I, Bonofiglio D, Cordella A, Hashim A, Györffy B, Simões BM, Clarke RB, Weisz A, Catalano S, Andò S. Leptin as a mediator of tumor-stromal interactions promotes breast cancer stem cell activity. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-03-06.

Determination of synthetic by-products and an intermediate in the colour additive D&C Orange No. 5 using high-performance liquid chromatography

Specifications in the US Code of Federal Regulations for the colour additive D&C Orange No. 5 (Colour Index No. 45370:1) limit the levels of the synthetic by-products 2-(3,5-dibromo-2,4-dihydroxybenzoyl)benzoic acid (Br2BBA) and brominated resorcinol (Br3R) as well as the level of the intermediate phthalic acid (PhthAc). The present work reports the development and application of a high-performance liquid chromatography (HPLC) method for the quantitative determination of these impurities in D&C Orange No. 5 and its lakes. Br2BBA, Br3R and PhthAc were quantified by using five-point calibration curves with data points that ranged from 0.010% to 0.700%, from 0.012% to 0.706% and from 0.006% to 1.383% by weight, respectively. The HPLC method was applied to the analysis of test portions from 11 lots of D&C Orange No. 5 and one lot of D&C Orange No. 5 lake submitted to the US Food and Drug Administration (USFDA) for certification.

Direct regulation of microRNA biogenesis and expression by estrogen receptor beta in hormone-responsive breast cancer

Estrogen effects on mammary epithelial and breast cancer (BC) cells are mediated by the nuclear receptors ERα and ERβ, transcription factors that display functional antagonism with each other, with ERβ acting as oncosuppressor and interfering with the effects of ERα on cell proliferation, tumor promotion and progression. Indeed, hormone-responsive, ERα+ BC cells often lack ERβ, which when present associates with a less aggressive clinical phenotype of the disease. Recent evidences point to a significant role of microRNAs (miRNAs) in BC, where specific miRNA expression profiles associate with distinct clinical and biological phenotypes of the lesion. Considering the possibility that ERβ might influence BC cell behavior via miRNAs, we compared miRNome expression in ERβ+ vs ERβ- hormone-responsive BC cells and found a widespread effect of this ER subtype on the expression pattern of these non-coding RNAs. More importantly, the expression pattern of 67 miRNAs, including 10 regulated by ERβ in BC cells, clearly distinguishes ERβ+, node-negative, from ERβ-, metastatic, mammary tumors. Molecular dissection of miRNA biogenesis revealed multiple mechanisms for direct regulation of this process by ERβ+ in BC cell nuclei. In particular, ERβ downregulates miR-30a by binding to two specific sites proximal to the gene and thereby inhibiting pri-miR synthesis. On the other hand, the receptor promotes miR-23b, -27b and 24-1 accumulation in the cell by binding in close proximity of the corresponding gene cluster and preventing in situ the inhibitory effects of ERα on pri-miR maturation by the p68/DDX5-Drosha microprocessor complex. These results indicate that cell autonomous regulation of miRNA expression is part of the mechanism of action of ERβ in BC cells and could contribute to establishment or maintenance of a less aggressive tumor phenotype mediated by this nuclear receptor.

The p63 target HBP1 is required for skin differentiation and stratification

Genetic experiments established that p63 is crucial for the development and maintenance of pluristratified epithelia. In the RNA interference (RNAi) screening for targets of p63 in keratinocytes, we identified the transcription factor, High Mobility Group (HMG) box protein 1 (HBP1). HBP1 is an HMG-containing repressor transiently induced during differentiation of several cell lineages. We investigated the relationship between the two factors: using RNAi, overexpression, chromatin immunoprecipitations and transient transfections with reporter constructs, we established that HBP1 is directly repressed by p63. This was further confirmed in vivo by evaluating expression in p63 knockout mice and in transgenics expressing p63 in basal keratinocytes. Consistent with these findings, expression of HBP1 increases upon differentiation of primary keratinocytes and HaCaT cells in culture, and it is higher in the upper layers of human skin. Inactivation of HBP1 by RNAi prevents differentiation of keratinocytes and stratification of organotypic skin cultures. Finally, we analyzed the keratinocyte transcriptomes after HBP1 RNAi; in addition to repression of growth-promoting genes, unexpected activation of differentiation genes was uncovered, coexisting with repression of other genes involved in epithelial cornification. Our data indicate that suppression of HBP1 is part of the growth-promoting strategy of p63 in the lower layers of epidermis and that HBP1 temporally coordinates expression of genes involved in stratification, leading to the formation of the skin barrier.

17beta-estradiol inhibits forskolin-induced vascular endothelial growth factor promoter in MCF-7 breast adenocarcinoma cells

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor whose expression is induced by the cAMP-dependent signalling pathway in several cell types, and by estrogens in some human breast cancer cells. Here, we investigated the cross-talk between estrogens and cAMP/PKA-dependent signalling pathway in human breast cancer MCF-7 cells. The results show that, in the absence of any CRE and ERE, forskolin induces whereas estrogens have no effect on VEGF promoter. Moreover, estrogens, through estrogen receptors, partly inhibit the forskolin-induced VEGF promoter in MCF-7 human breast cancer cells. Therefore, in breast cancers, estrogens could partly inhibit the effect of ligand-activated G protein-coupled receptors on VEGF expression.

Estrogens do not modify MAP kinase-dependent nuclear signaling during stimulation of early G(1) progression in human breast cancer cells

Estrogens are direct mitogens for hormone-responsive human breast cancercells, where they promote cell cycle progression and induce transcriptional activation of "immediate early" and cyclin genes. Nongenomic signaling by estrogens, including rapid changes of mitogen-activated protein(MAP) kinase and other signal-transduction-cascades activity, has been proposed to be essential for the mitogenic actions of these hormones and their nuclear receptors. Because regulation of gene transcription is considered a key step in cell cycle control by mitogenic protein kinase cascades, here we investigated the possibility that estrogen might induce the activation of extracellular signal-regulated kinase (Erk) 1/2-, c-Jun NH(2)-terminal kinase-, p38- or protein kinase A-responsive transcription factors in the cell nucleus during stimulation of early G(1) progression, a timing coincident with the maximum effects of these hormones on such enzyme activity. No significant changes in protein kinase-mediated transcription factor activity could be detected here after estrogen stimulation of either MCF-7 or ZR-75.1 cells. Furthermore, these steroids were able to induce activation of the human CCND1 gene promoter, accumulation of cyclin D1 and pRb phosphorylation, all key events in cell cycle stimulation by mitogens, even in the presence of Erk1/2 activation blockade by a MAP kinase-activating kinase (Mek)1/2 inhibitor. Thus, estrogens do not appear to convey significant protein kinase-dependent signaling to the cell nucleus during the early phases of human breast cancer cell stimulation. Furthermore, hormonal regulation of G(1) gene transcription can occur even without additional activation of the Mek-Erk1/2 pathway by estrogen receptors.

Structural assignment of isomeric 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione mono- and disulfonic acids by liquid chromatography electrospray and atmospheric pressure chemical ionization tandem mass spectrometry

Positionally isomeric 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione mono- and disulfonic acids give rise to similar electrospray ionization (ESI) and atmosphere pressure chemical ionization (APCI) mass spectra, which show very abundant MH(+) ions and negligible fragmentation. The MH(+) ions of these isomeric acids exhibit notably different behavior under collision-induced dissociation (CID) conditions. The acids with a sulfonic group at position 8' in the quinoline moiety, adjacent to the N-atom, exhibit highly abundant [MH - H(2)SO(3)](+) ions (m/z 272 for the mono- and m/z 352 for the disulfonic acids), which are of lower abundance in the CID spectra of isomers with the SO(3)H group at other positions, remote from the nitrogen atom. The latter isomers undergo efficient eliminations of SO(3) and HSO(3). The isomeric diacids with one SO(3)H group at position 4 of the indene-1,3(2H)-dione moiety, adjacent to one of the carbonyl groups, undergo highly efficient elimination of H(2)O. Mechanistic pathways, involving interactions between adjacent groups, are proposed for the above regiospecific fragmentations. Pronounced different behavior has been also observed in negative ion tandem mass spectrometric measurements of the sulfonic acids. The distinctive behavior of the isomeric acids was strongly pronounced when the measurements were performed with an ion trap mass spectrometer (LCQ), and much less so with a triple-stage quadrupole instrument (TSQ).

Cell type-specific induction of cyclin D and cyclin-dependent kinase inhibitor p27(kip1) expression by estrogen in rat endometrium

Cyclins, cyclin-dependent kinases (CDKs) and the CDK inhibitor p27(kip1) are known to be involved in the regulation of G(1)/S phase transition by estrogen in the rodent endometrium. Little is known, however, of the cell-specific location and regulation of these proteins during this process, or the way they mediate the differential effect of estrogen in the epithelium and stroma of the endometrium. Here we studied the cell-specific regulation of D-type cyclin (D(1-3)), of cyclin A and E, of CDK(2) and p27(kip1) by 17beta-estradiol in the endometrium of ovariectomized rats. Time-course changes in these proteins in the endometrium of ovariectomized rats were examined by immunohistochemistry at 2, 4, 8, 12, 20, 28 and 32 h after estrogen stimulation. The expression of proliferation cell nuclear antigen (PCNA) was also studied as a marker of proliferating cells. As expected from previous studies, all the proteins investigated were up-regulated by estrogen, with peak times from 8 to 32 h. The induction of cyclin D(1) is predominant in the glandular epithelium, whereas cyclin D(3) increases mainly in the luminal epithelium. The up-regulation of p27(kip1) is restricted to stromal cells with a 'gradient-like' expression pattern, in which the sub-epithelial (functional) layer showed stronger staining than the basal layer. The differential regulation of cyclins and p27(kip1) in the epithelium and stroma of the endometrium appear indicative of distinct actions of estrogen in different cell types in the uterus, as D-type cyclins mediate the proliferative effect of estrogen in epithelial cells while p27(kip1) might help prevent the same effect in the stroma.

Preparative separation of isomeric 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione monosulfonic acids of the color additive D&C Yellow No. 10 (quinoline yellow) by pH-zone-refining counter-current chromatography

The main components of the color additive D&C Yellow No. 10 (Quinoline Yellow, Color Index No. 47005), 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione-6'-sulfonic acid (6SA) and 2-(2-quinolinyl)-1H-indene-1,3(2H)-dione-8'-sulfonic acid (8SA), were isolated from the dye mixture by pH-zone-refining counter-current chromatography (CCC) in the ion-exchange mode. These positional isomers were separated from a portion of dye using sulfuric acid as the retainer acid and dodecylamine as the ligand (ion exchanger). The added ligand enhanced the partitioning of the hydrophilic components in the organic stationary phase of the two-phase solvent system that consisted of isoamyl alcohol-methyl tert.-butyl ether-acetonitrile-water (3:1:1:5). Thus, separation of 1.8 g of D&C Yellow No. 10 using the above method resulted in 0.6 g of 6SA and 0.18 g of 8SA of over 99% purity. The isolated compounds were characterized by mass spectrometry and proton nuclear magnetic resonance with correlated spectroscopy assignments. The study exemplifies a new field of applications for pH-zone-refining CCC, to the separation of positional isomers of strongly hydrophylic compounds containing sulfonic acid groups.

Inhibition of human breast cancer cell growth by blockade of the mevalonate-protein prenylation pathway is not prevented by overexpression of cyclin D1

Overexpression of the cyclin D1 (CCND1) gene, encoding a downstream effector of mitogenic signals that plays a central role in G1 phase progression, is often found in cancerous cells. In sporadic breast cancer (BC), this is one of the most frequent and early genetic lesions identified so far, found in more than 50% of the tumors. Inhibitors of the mevalonate/protein prenylation pathway belong to a new family of cancer therapeutic agents that act by blocking intracellular mitogenic signal transduction pathways, thereby preventing expansion of pre-cancerous foci and inhibiting growth of transformed cells. It is not known at present whether constitutively high intracellular levels of cyclin D1 might interfere with the cytostatic actions of mevalonate/protein prenylation inhibitors. This possibility was investigated here by assessing the cell cycle effects of Simvastatin, a non-toxic upstream inhibitor of the mevalonate pathway, on human BC MCF-7 cells expressing either normal or enhanced levels of cyclin D1 from of a stably transfected, tet-inducible expression vector. Results show that constitutive overexpression of this protein, such as that found in sporadic BCs, does not influence the growth inhibitory effects of Simvastatin in vitro. In addition, D1-overexpressing embryo fibroblasts were also found to be responsive to the cell cycle effects of mevalonate/protein prenylation pathway blockade, further suggesting that high intracellular levels of cyclin D1 do not prevent the cytostatic actions of compounds targeting this metabolic pathway.

Increased vascular endothelial growth factor 165 binding to kinase insert domain-containing receptor after infection of human endothelial cells by recombinant adenovirus encoding the Vegf(165) gene

BACKGROUND

The angiogenic effect of vascular endothelial growth factor (VEGF(165)) is mediated mainly through the high-affinity tyrosine kinase receptor VEGF-R2 (KDR/flk-1). This study examined the effects of VEGF overexpression by primary human endothelial cells (ECs), which do not express VEGF under physiological conditions, on cell proliferation, VEGF binding to the kinase insert domain-containing receptor (KDR), and KDR expression.

METHODS AND RESULTS

Human primary ECs and SMCs were infected by recombinant adenoviral vector encoding VEGF(165) (rAdVEGF). Proliferation rate, bromodeoxyuridine incorporation, (125)I-labeled VEGF(165) binding to the KDR receptor, and KDR expression were tested in the infected cells and in cells supplemented with VEGF protein. Enhanced proliferation and a significant increase in (125)I-VEGF(165) binding to the KDR receptor were induced by rAdVEGF infection of ECs (autocrine effect) as well as by addition of recombinant VEGF(165) to noninfected cells. Infection of ECs by rAdVEGF led to posttranscriptional upregulation of the KDR receptor, whereas KDR mRNA expression levels remained unchanged. Similar effects were observed with supplemented recombinant VEGF(165) to noninfected ECs; nevertheless, this phenomenon occurred only with high VEGF(165) concentrations (10 ng/mL).

CONCLUSIONS

The effect of VEGF(165) on proliferation and upregulation of KDR receptor expression demonstrated an autocrine phenomenon of EC sensitization. The fact that high concentrations of VEGF may be achieved in vivo by local continuous overexpression of VEGF(165) by gene transfer emphasizes the potential advantage of gene transfer over protein supplementation for therapeutic angiogenesis.

Identification of hypoxia-inducible factor 1 ancillary sequence and its function in vascular endothelial growth factor gene induction by hypoxia and nitric oxide

Transcription of hypoxia-inducible genes is regulated by hypoxia response elements (HREs) located in either the promoter or enhancer regions. Analysis of these elements reveals the presence of one or more binding sites for hypoxia-inducible factor 1 (HIF-1). Hypoxia-inducible genes include vascular endothelial growth factor (VEGF), erythropoietin, and glycolytic enzyme genes. Site-directed mutational analysis of the VEGF gene promoter revealed that an HIF-1 binding site (HBS) and its downstream HIF-1 ancillary sequence (HAS) within the HRE are required as cis-elements for the transcriptional activation of VEGF by either hypoxia or nitric oxide (NO). The core sequences of the HBS and the HAS were determined as TACGTG and CAGGT, respectively. These elements form an imperfect inverted repeat, and the spacing between these motifs is crucial for activity of the promoter. Gel shift assays demonstrate that as yet unknown protein complexes constitutively bind to the HAS regardless of the presence of these stimuli in several cell lines, in contrast with hypoxia- or NO-induced activation of HIF-1 binding to the HBS. A common structure of the HRE, which consists of the HBS and the HAS, is seen among several hypoxia-inducible genes, suggesting the presence of a novel mechanism mediated by the HAS for the regulation of these genes.

Insulin up-regulates vascular endothelial growth factor and stabilizes its messengers in endometrial adenocarcinoma cells

Angiogenesis is crucial for tumor growth and dissemination. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that promotes vascular growth and therefore tumoral growth and metastasis. Overweight, frequently associated with hyperinsulinemia, constitutes the major risk factor for endometrial carcinoma. Thus, elevated insulin levels may partly explain the increased risk of endometrial cancer observed in obese postmenopausal women. The aim of the present work was to test the role of insulin in the control of VEGF expression in endometrial carcinoma cells (HEC-1A). We have shown that insulin induced a biphasic expression of VEGF messenger ribonucleic acid, with an early, but low, induction (4 h of stimulation) and a delayed, but high, induction (24 h). The delayed effect of insulin on VEGF expression involved transcriptional and posttranscriptional regulation, as evidenced by the increased rate of VEGF transcription and the prolonged half-life of VEGF messenger ribonucleic acid. Simultaneously we observed higher levels of VEGF protein in the conditioned medium of stimulated cells compared with unstimulated ones. Therefore, insulin could contribute to the increased risk of endometrial carcinoma due to its ability to induce VEGF expression and thus participate in the maintenance of an angiogenic phenotype.

The antiestrogen ICI 182,780 inhibits proliferation of human breast cancer cells by interfering with multiple, sequential estrogen-regulated processes required for cell cycle completion

Antiestrogens are widely used for breast cancer treatment, where they act primarily by inhibiting the mitogenic action of estrogens on tumor cells. The effects of the pure antiestrogen ICI 182,780 on estrogen-regulated cell cycle phase-specific events were investigated here in synchronously cycling human breast cancer (HBC) cells. In early G(1)-arrested MCF-7 or ZR-75.1 cells, 17beta-estradiol (E2) induces rapid activation of the cyclin/Cdk/pRb pathway, as demonstrated by D-type G(1) cyclins accumulation during the first few hours of hormonal stimulation, followed by sequential accumulation of E, A and B1 cyclins and progressive pRb phosphorylation, as cells progress through the cell cycle. When added to quiescent cells together with E2, ICI 182,780 prevents all of the above hormonal effects. Interestingly, in mid-G(1) cells (2-8 h into estrogen stimulation) the antiestrogen causes rapid reversal of hormone-induced D-type cyclins accumulation and pRb phosphorylation, and still fully inhibits G(1)-S transition rate, while in late-G(1) cells it does not prevent S phase entry but still inhibits significantly DNA synthesis rate, S-phase cyclins accumulation and pRb hyperphosphorylation. These results indicate that pure antiestrogens prevent multiple estrogen-induced cell cycle-regulatory events, each timed to allow efficient G(1) completion, G(1)-S transition, DNA synthesis and cell cycle completion.

Therapeutic angiogenesis for ischemic syndromes

Disease caused by atherosclerosis are the most common causes of morbidity and mortality in western societies. The inadequacy of current therapeutic modalities is most pronounced in the significant proportion of patients with arterial obstructive disease, in whom anatomical and technical limitations rule out the possibility of angioplasty or surgery. Therefore, less invasive approaches are necessary to treat these patients. The development of collateral circulation improves blood flow to ischemic tissues and to alleviate ischemia-related symptoms. Our project concentrates on enhancement of the natural mechanism of angiogenesis by adenoviral based vector encoding vascular endothelial growth factor as an angiogenic factor. The aim of our study was to determine the efficacy of human vascular cell infection by adenoviral based vectors in vitro and in vivo. Human saphenous vein endothelial cells and smooth muscle cells were infected by adenoviral vectors encoding the lacZ and VEGF genes (rAdlacZ, rAdVEGF). VEGF expression by adenoviral vector-infected cells was detected by western analysis and its biological activity was examined by proliferation assay. The feasibility of adenoviral based gene transfer in vivo was evaluated after direct femoral artery injection of rAdlacZ in the rat. Vascular endothelial and smooth muscle cells expressed high levels of VEGF following rAdVEGF infection. The mitogenic effect of VEGF was validated by threefold increase in EC proliferation rate in comparison to the control groups. In vivo gene transfer was demonstrated using lacZ gene transfer to arterial wall cells in the superficial femoral artery. Efficient adenoviral based gene delivery was demonstrated both in vitro and in vivo. VEGF over-expression enhanced endothelial cell proliferation, which is the key step for induction of angiogenesis.

Regulation of vascular endothelial growth factor expression by insulin-like growth factor-I in endometrial adenocarcinoma cells

Angiogenesis is crucial for tumor growth and dissemination. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that promotes endothelial cell proliferation and chemotaxis. VEGF occurs as 5 isoforms, as a result of an alternatively spliced transcript that originates from one gene, of which the 2 majors are the VEGF 121 and 165 isoforms. Our aim was firstly to determine the role of Insulin-like Growth Factor-I (IGF-I) in the regulation of VEGF expression in endometrial adenocarcinoma cells and then the mechanism by which this regulation occurs. IGF-I treatment of HEC-1A cells provoked an increase of VEGF mRNA expression that peaked at 48 hr with a 165 isoform mRNA more abundant than the 121 isoform. The IGF-I action was confirmed at the protein level, whose concentration was increased in the conditioned media. In experiments using transient transfection of VEGF promoter-luciferase constructs, the IGF-I failed to increase the activity of the VEGF promoter after a 24-hr period of IGF-I treatment, while the addition of Actinomycin D showed an increase of the VEGF mRNA half-life. Most interestingly, Northern blot analysis showed a different stability of the 2 major VEGF isoform mRNAs (VEGF 121 and 165), of which the 121 isoform was more stable than the 165 isoform. The IGF-I treatment prolonged the half-life of both of the VEGF isoform mRNAs. Our results suggest that IGF-I regulates VEGF expression in endometrial adenocarcinoma cells at the post-transcriptional level by enhancing the stabilization of the 2 major VEGF isoform mRNAs (VEGF(121) and VEGF(165)). In addition to its proliferative functions, IGF-I induces VEGF expression and participates in the maintenance of an angiogenic phenotype.

Hypoxia response element of the human vascular endothelial growth factor gene mediates transcriptional regulation by nitric oxide: control of hypoxia-inducible factor-1 activity by nitric oxide

Nitric oxide (NO) regulates production of vascular endothelial growth factor (VEGF) by normal and transformed cells. We demonstrate that NO donors may up-regulate the activity of the human VEGF promoter in normoxic human glioblastoma and hepatoma cells independent of a cyclic guanosine monophosphate-mediated pathway. Deletion and mutation analysis of the VEGF promoter indicates that the NO-responsive cis-elements are the hypoxia-inducible factor-1 (HIF-1) binding site and an adjacent ancillary sequence that is located immediately downstream within the hypoxia-response element (HRE). This work demonstrates that the HRE of this promoter is the primary target of NO. In addition, VEGF gene regulation by NO, as well as by hypoxia, is potentiated by the AP-1 element of the gene. Our study also reveals that NO and hypoxia induce an increase in HIF-1 binding activity and HIF-1alpha protein levels, both in the nucleus and the whole cell. These results suggest that there are common features of the NO and hypoxic pathways of VEGF induction, while in part, NO mediates gene transcription by a mechanism distinct from hypoxia. This is demonstrated by a difference in sensitivity to guanylate cyclase inhibitors and a different pattern of HIF-1 binding. These results show that there is a primary role for NO in the control of VEGF synthesis and in cell adaptations to hypoxia. (Blood. 2000;95:189-197)

Rapid quantification of hexachlorobenzene in the color additives D&C Red Nos. 27 and 28 (phloxine B) using solid-phase microextraction and gas chromatography-mass spectrometry

The present paper describes the development of a method for the quantification of hexachlorobenzene (HCB) in the color additives D&C Red Nos. 27 and 28 (phloxine B) using solid-phase microextraction followed by gas chromatography-mass spectrometry (GC-MS) analysis. The method is simple and fast (1 h for each analysis), generates little solvent waste, and does not involve a solid matrix, thus permitting a more efficient extraction than does a previously developed Soxhlet extraction-GC-MS method. Test portions from 30 batches of US-certified color additives D&C Red Nos. 27 and 28 were analyzed for HCB using the new method. Those batches represent domestic (five) and foreign (one) manufacturers that requested certification for the colors during the past four years. All the samples contained HCB, ranging from 0.2 ppm to 244.3 ppm. The analyses revealed significant differences in the levels of HCB across batches from the same manufacturer as well as among different manufacturers. The range of HCB levels found in the analyzed batches (0.2-244.3 ppm) suggest that the contamination with HCB may be decreased by avoiding use of starting material (tetrachlorophthalic anhydride) heavily contaminated with HCB.

ERE environment- and cell type-specific transcriptional effects of estrogen in normal endometrial cells

Our previous results have suggested a repression of E2 (17beta-estradiol) effect on the c-fos gene of cultured guinea-pig endometrial cells. To investigate this repression, the expression of three human c-fos gene recombinants, pFC1-BL (-2250/+41), pFC2-BL (-1400/+41) and pFC2E (-1300/-1050 and -230/+41), known to be E2-responsive in Hela cells, was studied in stromal (SC) and glandular epithelial cells (GEC). In both cellular types, pFC1-BL was not induced by E2, even in the presence of growth factors or co-transfected estrogen receptor. The pattern of pFC2-BL and pFC2E expression was strikingly different and depended on the cellular type: pFC2-BL and pFC2E induction was restricted to the glandular epithelial cells and did not occur in the SCs. We argue for a repression of E2 action which is dependent on the estrogen-responsive cis-acting element (ERE) environment and also cell type-specific involving DNA/protein and/or protein/protein interactions with cellular type-specific factors.

Constitutive overexpression of cyclin D1 does not prevent inhibition of hormone-responsive human breast cancer cell growth by antiestrogens

Cyclin D1 is a target for positive regulation by estrogens in growth-responsive cells, in which it mediates their mitogenic effects. Amplification and overexpression of the cyclin D1 gene (CCND1) might thus represent a genetic lesion inducing hormone-independent growth of transformed cells. Indeed, cyclin D1 overexpression has been found in up to 50% of primary breast cancers, and in about one-third of these cases, this is linked to amplification of the 11q13 chromosomal region, which also includes the CCND1 gene. These tumors are predominantly estrogen receptor-positive, and for this reason, these patients are often selected for adjuvant antiestrogen therapy. No information is available, however, as to whether cyclin D1 overexpression due to gene amplification might interfere with and reduce antiestrogen efficacy. This was investigated here by taking advantage of an experimental model that reproduces cyclin D1 overexpression resulting from increased CCND1 gene dosage in hormone-responsive human breast cancer cells. For this, MCF-7 cells stably transfected with a tet-inducible cyclin D1 expression vector were tested for their in vitro response to steroidal (ICI 182,780) and nonsteroidal (trans-4-hydroxytamoxifen) antiestrogens under condition of low (endogenous only) or high (exogenous) cyclin D1 levels. Results show that although cyclin D1 overexpression seems to interfere with the early cell cycle effects of antiestrogens, it does not prevent their cytostatic actions, so that growth of cyclin-overexpressing MCF-7 cells is still efficiently inhibited in vitro by these drugs.

Inhibition of inducible nitric oxide synthase gene expression by glucocorticoid-induced protein(s) in lipopolysaccharide-stimulated J774 cells

Glucocorticoids inhibit inducible-type NO synthase activity in a variety of cell types. We report here that proteins recovered from the medium of dexamethasone-treated J774 macrophages (1, 10, 100 microg/ml) inhibited lipopolysaccharide-stimulated nitrite generation by 10.0 +/- 3.0%, 32.3 +/- 5.3% and 55.0 +/- 6.0%, respectively, and inducible NO synthase mRNA expression in these cells. Immunoblotting analysis of crude and partially purified glucocorticoid-induced proteins with an anti-lipocortin-1 polyclonal antiserum revealed the presence of lipocortin-1-like immunoreactive species with a molecular mass of 35-37 kDa. Furthermore, inhibition of lipopolysaccharide-induced nitrite production by glucocorticoid-induced proteins in J774 cells was reversed by addition of anti-lipocortin-1 neutralizing polyclonal antibody (1:60 dilution; 4 h before lipopolysaccharide). Comparison of glucocorticoid-induced proteins inhibition of both nitrite production and inducible NO synthase mRNA expression suggests that these effects result mainly from inhibition of lipopolysaccharide-mediated inducible NO synthase gene expression. These results indicate that negative regulation of inducible NO synthase by glucocorticoids is, at least in part, mediated by glucocorticoid-induced proteins that involve also members of the lipocortin-like superfamily.

Angiogenesis by gene therapy: a new horizon for myocardial revascularization?

The concept of therapeutic angiogenesis is based on the premise that the potential for vascular growth inherent in vascular tissue can be utilized to promote the development of new blood vessels under the influence of the appropriate growth factors. Direct application of growth factors of the fibroblast (acidic, basic fibroblast growth factor, FGF-5), endothelial (vascular endothelial growth factor) and other series has been effective in preliminary studies. Angiogenesis by gene transfer provides an attractive alternative, with the advantage that the protein may continue to be secreted for a longer period of time and that the gene may be targeted to specific tissues to enhance efficacy and reduce systemic side effects. Angiogenesis by gene transfer is currently under investigation using a variety of growth factors and a wide array of potential delivery systems. These include application of the gene as naked DNA or by viral vector in the proximal vessel by direct intravascular injection, interventional cardiologic techniques (hydrogel coating on balloon, double balloon system, stent implantation) or by direct application to adventitia, pericardium or ischemic tissue distal to the site of arterial obstruction. As our understanding of the molecular and genetic processes underlying angiogenesis increases, and as we examine the results of preliminary animal and human protocols, we hope to develop the potential of angiogenesis by gene transfer for therapeutic use.

Estrogen induces early and timed activation of cyclin-dependent kinases 4, 5, and 6 and increases cyclin messenger ribonucleic acid expression in rat uterus

Cyclin-dependent kinases (cdks) are serine-threonine protein kinases that play a key role in the regulation of the mitotic cycle, in transcription initiation, and in the control of specific metabolic pathways in eukaryotic cells. cdk activity is controlled via phosphode-phosphorylation of the catalytic subunits of these enzymes and their physical association with cyclins and cdk inhibitors. In adult rats, estrogen stimulation results in massive proliferation of endometrial epithelial cells, accompanied by functional and structural modifications in all other tissue components of the uterus. We report here that administration of 17 beta-estradiol (E2) to adult ovariectomized rats induces within the first 25 h significant activation of cdk 4, 5, and 6, but not cdk 2, in the uterus, accompanied by increased expression of D-type (D1-3), A and E cyclin messenger RNAs (mRNAs). Furthermore, expression of the cdk inhibitor p27Kip1, a key regulator of uterine functions, is induced by E2 in this organ. Analysis of RNA extracted from E2-stimulated rat endometria shows early accumulation of D1 and D3, but not D2, cyclin mRNA, preceded by transient accumulation of c-fos mRNA. These results indicate an involvement of cdks and cyclins in estrogen actions in adult rat uterus and suggest that cyclins D1 and D3 are part of the molecular pathway that allows hormonal regulation of G1 progression in endometrial cells.

17beta-Estradiol induces cyclin D1 gene transcription, p36D1-p34cdk4 complex activation and p105Rb phosphorylation during mitogenic stimulation of G(1)-arrested human breast cancer cells

MCF-7 human breast cancer cells express functional estrogen receptor and grow in response to estrogen stimulation. G(1)-synchronized MCF-7 cells, made quiescent by exposure to the HMG-CoA reductase inhibitor Simvastatin in estrogen-free medium, readily resume cell cycle progression upon stimulation with 17beta-estradiol (E(2)), even under conditions where polypeptide growth factor-triggered signal transduction pathways are inhibited by the continuous presence of Simvastatin in the culture medium. Under these conditions, cyclin D(1) gene transcription is transiently induced within the first 1-9 h of stimulation, as shown by the accumulation of cyclin D(1) mRNA and protein (p36(D(1))) in the cell and by enhanced expression of stably transfected D(1) promoter-luciferase hybrid genes. Estrogen-induced p36(D(1)) associates readily with p32(cdk2) and p34(cdk4), but not with p31(cdk5), which is however abundantly expressed in these cells. Only p36(D(1))-p34(cdk4) complexes are activated by E(2), as detected in cell extracts by immunoprecipitation with anti-D(1) antibodies followed by assessment of phosphotransferase activity toward the retinoblastoma (Rb) gene product and by analysis of p105(Rb) phosphorylation in vivo. An estrogen-responsive regulatory region has been mapped within the first 944 bp upstream of the transcriptional startsite of the human D(1) gene. Sequence analysis of this DNA region reveals that the cis-acting elements responsive to estrogen are likely to be different in this case from the canonical EREs.

Fragmentation of isomeric N-quinolinylphthalimides on electron impact ionization

The isomeric 2-, 3-, 5-, 6- and 8-quinolinylphthalimides give rise to different electron impact ionization mass spectra, which permit easy distinction. The specific fragmentation process are rationalized in terms of proximity effects and stabilization of cyclic ion structures. Collision-induced dissociation spectra were used to support the proposed ion structures of major fragment ions.

Regulation of the mouse inducible-type nitric oxide synthase gene promoter by interferon-gamma, bacterial lipopolysaccharide and NG-monomethyl-L-arginine

Cytokines and bacterial lipopolysaccharides (LPSs) stimulate nitric oxide production in macrophages by inducing transcription of the gene coding for the inducible isoform of nitric oxide synthase (iNOS). We have cloned the mouse iNOS gene promoter and analysed its structural features and its response to interferon-gamma (IFN-gamma) and Escherichia coli LPS in RAW 264.7 mouse macrophage-like cells. Transcription of a recombinant reporter gene including the promoter and 4 kb of its 5'-flanking DNA, linked to the bacterial chloramphenicol acetyltransferase (CAT) reporter gene, is stimulated by IFN-gamma and, more efficiently, by LPS upon transient transfection in RAW 264.7 cells. Two upstream DNA regions are required for maximal promoter activation of LPS: the first maps between positions -1541 and -775 and the other between -420 and -47, with respect to the major transcriptional start site of the iNOS gene. The upstream-most region also mediates promoter trans-activation by IFN-gamma. As reported earlier for transcription of the endogenous iNOS gene, combined stimulation of RAW 264.7 cells with IFN-gamma and LPS results in lower activation of the transfected promoter, when compared with LPS alone. NG-Monomethyl-L-arginine, a competitive inhibitor of nitric oxide synthase activity, enhances iNOS gene mRNA induction and promoter activation by IFN-gamma and LPS, indicating that nitric oxide can influence negatively the reponsiveness of this gene to inducers. These results suggest the possibility of a negative regulatory feedback exerted by iNOS on the transcriptional activation of its own gene.

Isolation of 4'-bromo-4,5,6,7-tetrachlorofluorescein from a synthetic mixture by pH-zone-refining counter-current chromatography with continuous pH monitoring

A synthetic mixture containing mainly 4'-bromo-4,5,6,7-tetrachlorofluorescein (4'BrTCF, ca. 25% by high-performance liquid chromatography) was prepared by direct bromination of tetrachlorofluorescein in ethanol. The 4'BrTCF was isolated and purified by pH-zone-refining counter-current chromatography (CCC), using two different two-phase solvent systems: diethyl ether-acetonitrile-water (4:1:5,v/v) and ter.-butyl methyl ether-water (1:1,v/v). For each system, the upper organic phase was acidified and used as the stationary phase and the lower aqueous phase was made basic and used as the mobile phase. pH-Zone-refining CCC of two 5-g batches of the crude mixture yielded 1.65 g of 4'BrTCF that was ca. 95% pure by HPLC. For these separations, a commercial counter-current chromatograph was fitted with a pH electrode in a flow cell to record the pH of the effluent "on line,' thereby replacing the tedious and time-consuming manual measurement of the pH of each fraction. Additionally, UV spectra of the effluent were continuously monitored and stored by using a computerized scanning UV-Vis detector equipped with an adjustable short-pathlength flow cell.

Stimulation of human breast cancer MCF-7 cells with estrogen prevents cell cycle arrest by HMG-CoA reductase inhibitors

Inhibitors of 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase, such as Simvastatin and Lovastatin, reduce the rate of DNA synthesis and proliferation of a wide variety of cell types in vitro, by inducing a cell cycle arrest in G1. In estrogen-free medium, DNA synthesis is reduced by more that 90% following exposure of normal and transformed human breast epithelia] cells to 20 microM Simvastatin or Lovastatin for 24 to 42 hrs. We show here that stimulation of estrogen responsive MCF-7 cells with nanomolar concentrations of 17beta-estradiol (E2) prevents inhibition of DNA synthesis by these compounds. The effect of the hormone is antagonized by both steroidal and non steroidal antiestrogens, and it is not detectable in estrogen receptor-negative MCF-10a cells. Cell cycle analysis demonstrates that HMG-CoA reductase inhibitors are unable to induce G1 arrest of MCF-7 cells in the presence of E2.

17 beta-Estradiol overcomes a G1 block induced by HMG-CoA reductase inhibitors and fosters cell cycle progression without inducing ERK-1 and -2 MAP kinases activation

HMG-CoA reductase inhibitors, such as Lovastatin and Simvastatin, cause cell cycle arrest by interfering with the mitogenic activity of mitogens present in culture media. Cells are induced to pause in G1 and can readily resume growth upon removal of the enzymatic block. Estrogens, acting via their nuclear receptor, are mitogens for different normal and transformed cell types, where they foster cell cycle progression and cell division. In estrogen-responsive MCF-7 human breast cancer cells, but not in non responsive cells, 17 beta-estradiol (E2) induces cells arrested with Lovastatin or Simvastatin to proliferate in the presence of inhibitor, without restoring HMG-CoA reductase activity or affecting the protein prenylation pattern. Mitogenic stimulation of G1-arrested MCF-7 cells with E2 includes primary transcriptional activation of c-fos, accompanied by transient binding in vivo of the estrogen receptor and/or other factors to the ERE and the estrogen-responsive DNA region of this proto-oncogene, as detected by dimethylsulphate genomic footprinting analysis. Mitogenic stimulation of growth-arrested MCF-7 cells by E2 occurs, under these conditions, without evident activation of ERK-1 and -2 kinases, and thus independently from the mitogen-responsive signal transduction pathways that converge on these enzymes.

Implication of nitric oxide synthase in carcinogenesis: analysis of the human inducible nitric oxide synthase gene

Nitric oxide (NO) is a newly identified, multifunctional biological mediator. However, it also has deleterious effects on biological materials. For instance, nucleic acids, proteins, and some prosthetic groups of enzymes can be modified by NO or its reaction products with other reactive oxygen species. Endogenous nitrosamine formation through the reaction of NO or its oxidized products with amines might be involved in carcinogenesis. These deleterious effects of NO are often associated with inflammatory processes both in experimental animals and human. We analyzed the molecular mechanism of control of expression of the inducible nitric oxide synthase (NOS) gene in mouse cells by cloning its putative promoter region. This promoter responded to various cytokines and endotoxin similarly to the endogenous NOS gene in mouse cells. No appreciable induction of NOS was observed in human peripheral blood cells, but induction was detected in a human glioblastoma cell line A-172. Therefore, the human inducible NOS cDNA was cloned from A-172 cells and its cDNA-deduced amino acid sequence found to have about 80% similarity to those of both mouse and rat inducible NOSs. The effects of various cytokines on the induction of the gene were somewhat different from those observed in mouse cells, but the mouse promoter responded to these cytokines similarly to the endogenous NOS gene in human cells, indicating functional similarity of cis-elements of the genes encoding both human and mouse inducible NOS. Structural analysis of the human inducible NOS gene by Southern blot analysis revealed putative genetic restriction fragment length polymorphism in intron 5.(ABSTRACT TRUNCATED AT 250 WORDS)

Inducible nitric oxide synthase in a human glioblastoma cell line

Nitric oxide synthase (NOS) activity was induced in the cytosol of A-172 cells by treatment with lipopolysaccharide, tumor necrosis factor-alpha, and interferon-gamma. A 130-kDa human inducible NOS (iNOS) protein was detected with anti-rat iNOS antibody by western blot analysis. Northern blot analysis showed that the iNOS mRNA was approximately 4.5 kb, using a cDNA fragment for human iNOS, isolated from stimulated A-172 cells by reverse transcriptase-PCR, as a probe. The mRNA was induced by interferon-gamma at a trace level, and its expression was synergistically enhanced by simultaneous addition of lipopolysaccharide, tumor necrosis factor-alpha, and, to a larger extent, interleukin-1 beta. The mRNA expression was blocked by coincubation with actinomycin D or cycloheximide. Furthermore, by transfecting the mouse iNOS gene promoter into A-172 cells, transcriptional activation of the iNOS gene was detected in these cells upon stimulation with lipopolysaccharide and cytokines. The pattern of promoter activation correlated well with that of iNOS mRNA expression upon stimulation. These data indicate that expression of iNOS is transcriptionally regulated in A-172 cells. This process requires de novo protein synthesis with a mechanism similar to that in place in mouse macrophages.

Preparative separation of stereoisomeric 1-methyl-4-methoxymethylcyclohexanecarboxylic acids by pH-zone-refining counter-current chromatography

The application of pH-zone-refining counter-current chromatography (CCC) to the preparative separation of stereoisomeric acids is described. The separation was accomplished on the basis of the difference in acidity of the two stereoisomers. pH-Zone-refining CCC of 400 mg of a crude synthetic mixture of stereoisomeric 1-methyl-4-methoxymethylcyclohexanecarboxylic acids yielded 49.5 and 40 mg of the pure Z- and E-stereoisomers respectively. The two-phase solvent system consisted of hexane-ethyl acetate-methanol-water (1:1:1:1). Trifluoro acetic and octanoic acids were used as retainer acids. The eluent base was aqueous ammonia. The eluted fraction were monitored by gas chromatography-mass spectrometry.

Preparative separation of components of the color additive D&C Red No. 28 (phloxine B) by pH-zone-refining counter-current chromatography

A pH-zone-refining counter-current chromatographic method was developed for the preparative (multigram) separation and purification of components of the commercial color additive D&C Red No. 28 (phloxine B). The chromatography of 3 and 6 g of color additive yielded 1.07 and 4.06 g, respectively, of pure 2',4',5',7'-tetrabromo-4,5,6,7-tetrachlorofluorescein, the principal component of D&C Red No. 28. The importance of the quantity of retainer acid (trifluoroacetic acid) relative to the amount of salt in the color additive is discussed.

IFN consensus sequence binding protein (ICSBP) is a conditional repressor of IFN inducible promoters

IFN stimulated genes (ISGs) contain common DNA motif termed IFN consensus sequence (ICS) at their promoters that enable IFN responsiveness. Different transcription factors capable of interacting with the ICS have been described. Previously, we reported the cloning of a factor capable of binding to the ICS (ICSBP) that demonstrates similarity at DNA the binding domain with three other ICS binding factor, i.e. IRF-1, IRF-2 and ISGF3 gamma. ICSBP is expressed constitutively in hematopoietic cells and its expression is further induced by IFN-gamma. This is a negative trans-acting regulator of ISGs; however, its effect is attenuated following prolonged exposures of cells to both types of IFNs. In this communication, we show that short exposures of cells to IFNs (priming) are sufficient to alleviate ICSBP mediated repression. Further, exposure of primed cells to the synthetic dsRNA (polyl-polyC) results in total abrogation of ICSBP repression. In an attempt to unravel the molecular mechanism governing this conditional repression of ICSBP, the direct involvement of transcriptional activator IRF-1 is demonstrated. We postulate that constitutive expression of ICSBP in hematopoietic cells is mediating submaximal expression of ISGs such as MHC class I. Our data demonstrate that IRF-1 competes with ICSBP for the binding to the ISRE element, resulting in the alleviation of ICSBP repression. Thus, the magnitude of ISGs expression is a result of a fine balance between positive and negative regulators.

Dual mechanism for the control of inducible-type NO synthase gene expression in macrophages during activation by interferon-gamma and bacterial lipopolysaccharide. Transcriptional and post-transcriptional regulation

Production of nitric oxide (NO) by macrophages is enhanced upon activation by bacterial endotoxins and cytokines mainly via an increase of the intracellular content of the inducible isoform of nitric oxide synthase (i-NOS). We have studied in detail the effect of several modulators of macrophage activity on steady state levels of i-NOS mRNA in the mouse macrophage-like cell line RAW 264.7. Bacterial lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) were found to be effective inducers of i-NOS mRNA, in accordance with their known ability to stimulate both i-NOS activity and NO production in macrophages from different sources, while TNF-alpha, IL-1, or IL-6 was ineffective in this regard. Accumulation of i-NOS mRNA in response to either LPS or IFN-gamma stimulation was accompanied by increased i-NOS gene transcription, as detected both by using a nuclear "run-on" transcription assay and by transient transfection of the cloned gene promoter in RAW 264.7 cells. Co-stimulation of the cells with both inducers resulted in higher steady state levels of i-NOS mRNA in the absence, however, of a corresponding potentiation of the rate of gene transcription. This was due primarily to a considerable effect of LPS on i-NOS mRNA stability, with prolongation of its half-life from 1-1.5 h, in the presence of IFN-gamma alone, to 4-6 h in the presence of both LPS and IFN-gamma.

Enhancement of inducible-type NO synthase gene transcription by protein synthesis inhibitors. Activation of an intracellular signal transduction pathway by low concentrations of cycloheximide

Treatment of mouse macrophage-like RAW 264.7 cells with certain protein synthesis inhibitors is followed by accumulation of the mRNA for the inducible isoform of nitric oxide synthase (i-NOS). The activity of these compounds on the i-NOS gene in RAW 264.7 cells was analyzed here in detail. Results show that both cycloheximide and anisomycin can efficiently induce i-NOS mRNA, even when used at concentrations so low (0.25 microgram/ml) to have only negligible effects on protein synthesis; puromycin, on the other hand, shows only a limited effect on i-NOS mRNA expression, detectable only when cells are treated with higher concentrations of inhibitor (25 micrograms/ml). In RAW 264.7 cells, low concentrations of cycloheximide trigger an immediate-early gene response, as indicated by induction of c-fos and JE mRNAs, and can efficiently activate transcription of transiently transfected recombinant reporter genes including either the i-NOS or the c-fos gene promoters.

Functional antagonism between the estrogen receptor and Fos in the regulation of c-fos protooncogene transcription

Estrogen hormones induce transient transcriptional activation of c-fos during the early phases of mitogenic stimulation of target cells. This is mediated by a functional estrogen response element (ERE) that in the human c-fos gene is localized 1kb up-stream of the transcription start site. This is the first known example of transient transcriptional activation induced by a steroid hormone acting via its nuclear receptor. Starting with the hypothesis that the product of c-fos (Fos) interferes with estrogen receptor (ER) activity on this gene promoter, generating in this way a feedback inhibition mechanism responsible for the rapid transcriptional down-regulation detected in vivo, we tested the effects of Fos overexpression on ER-mediated activation of the c-fos promoter in transfected HeLa cells. Transient transfection of an ER expression vector is followed by hormone-dependent trans-activation of reporter genes comprising the c-fos ERE linked to its own promoter. Coexpression of Fos in the cell induces a significant reduction in the activity of ER on the reporter genes. Fos antagonism is effective on both transcription activation functions of the receptor molecule and is independent of the nature of the target promoter. Furthermore, under the same experimental conditions, the estrogen-receptor complex antagonizes activation of an AP-1-responsive test gene by Fos. ER mutants deprived of the DNA-binding domain are efficient inhibitors of Fos activity, indicating that reciprocal antagonism is likely to be mediated by the formation of inactive complexes between the two factors. These results reveal the existence of a functional interference between the ER and Fos for regulation of c-fos protooncogene transcription. It is the first case in which the product of an estrogen-induced growth-related gene is shown to exert a negative feedback control on ER regulation of its own promoter.

Nasal distribution of budesonide inhaled via a powder inhaler

The distribution pattern of budesonide in the nasal passages and lungs was investigated in 10 healthy subjects after nasal inhalation. The subjects inhaled drug powder, radiolabelled with 99mTc, at maximum flow rate (46.3 +/- 6.8 l/min) and at 29.9 +/- 2.5 l/min via Turbuhaler. At both flows, the majority of the dose was deposited in the anterior part of the nasal cavity on a single, rather localized area, but some particles also penetrated more posteriorly into the main nasal passages and to the lungs. At maximum flow rate the nasal deposition was 65.2% (range 39.5-84.1%) and the lung deposition 4.7% (range 1.4-9.3%) of the metered dose, and at 30 l/min, the nasal deposition was 67.6% (range 49.7-81.6%) and the lung deposition was 4.2% (range 1.7-7.9%). A large fraction of the metered dose was deposited in the nasal adaptor of the inhaler during the administration (mean values 29 and 28%, for the two inhalation flows). Of the dose actually reaching the subject, 91 and 93% (mean values) was deposited in the nose. There were no statistically significant differences in distribution pattern between the two inhalation flows.

Human interferon consensus sequence binding protein is a negative regulator of enhancer elements common to interferon-inducible genes

The promoter regions of many interferon-inducible genes share a short DNA sequence motif, termed the interferon consensus sequence (ICS) to which several regulatory proteins bind. A murine cDNA which encodes an ICS binding protein has been reported (M-ICSBP). The cloning of the human homologue of ICSBP (H-ICSBP) is described. H-ICSBP shares high sequence homology with its murine cognate. The derived sequence of H-ICSBP reveals restricted homology within the first 120 amino acids to three other interferon regulatory factors, IRF-1, IRF-2, and ISGF3 gamma. Truncated ICSBP lacking the first 33 amino-terminal amino acids fails to bind to the ICS, indicating that at least part of the DNA binding domain is located within the well conserved amino terminus. H-ICSBP is expressed exclusively in cell lines of hematopoietic origin. The results of transient transfection assays carried out either in hematopoietic or nonhematopoietic cells suggest that ICSBP acts as a negative regulatory factor on ICS-containing promoters. Furthermore, either interferon-gamma (IFN-gamma) or IFN-beta can alleviate the repression mediated by ICSBP. Therefore, ICSBP may be involved in maintaining submaximal transcriptional activity of IFN-inducible genes in hematopoietic cells. IFN treatment would then alleviate repression allowing maximal transcriptional activity of these genes.