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The adhesion of breast adenocarcinoma cells (MDA-MB-231) to human umbilical vein endothelial cells (HUVEC) was studied in whole blood and under varying flow conditions. This study was done on HUVEC either kept under static conditions or pre-conditioned in flow for 2 hours at a shear stress of 5 or 13 dyn/cm[SUP2]. Coverslips coated by HUVEC were placed in a parallel plate perfusion chamber and perfused at a shear rate of 300 or 1500 sec[SUP-1] with heparin-anticoagulated blood containing [SUP111]In labelled MDA-MB-231 cells. We report here the optimal conditions for studying the adhesion of MDA-MB-231 to endothelial cells under shear constraints corresponding to those observed into small and medium sized arteries. [ABSTRACT FROM AUTHOR]

Introduction: The poor efficacy of various anti-cancer treatments against metastatic cells has focused attention on the role of tumor microenvironment in cancer progression. To understand the contribution of the extracellular matrix (ECM) environment to this phenomenon, we isolated ECM surrogate invading cell populations from MDA-MB-231 breast cancer cells and studied their genotype and malignant phenotype., Methods: We isolated invasive subpopulations (INV) from non invasive populations (REF) using a 2D-Matrigel assay, a surrogate of basal membrane passage. INV and REF populations were investigated by microarray assay and for their capacities to adhere, invade and transmigrate in vitro, and to form metastases in nude mice., Results: REF and INV subpopulations were stable in culture and present different transcriptome profiles. INV cells were characterized by reduced expression of cell adhesion and cell-cell junction genes (44% of down regulated genes) and by a gain in expression of anti-apoptotic and pro-angiogenic gene sets. In line with this observation, in vitro INV cells showed reduced adhesion and increased motility through endothelial monolayers and fibronectin. When injected into the circulation, INV cells induced metastases formation, and reduced injected mice survival by up to 80% as compared to REF cells. In nude mice, INV xenografts grew rapidly inducing vessel formation and displaying resistance to apoptosis., Conclusion: Our findings reveal that the in vitro ECM microenvironment per se was sufficient to select for tumor cells with a stable metastatic phenotype in vivo characterized by loss of adhesion molecules expression and induction of pro-angiogenic and survival factors.

Mutual interactions between human breast cancer cells and endothelial cells were studied in a model mimicking tumor cell intravasation. MDA-MB-231 tumor cells and human umbilical vein endothelial cells (HUVEC) were cocultured on opposite sides of a Transwell filter allowing tumor cell contacts with the basement membrane of the HUVEC forming endothelium and tumor cell transendothelial migration. Confocal microscopy analysis showed that transmigrating MDA-MB-231 cells lay under the HUVEC, thereby inducing HUVEC detachment and tumor cell-HUVEC contact-dependent apoptosis. GM6001 a matrix metalloproteinase (MMP) inhibitor inhibited almost completely, the MDA-MB-231 cell transendothelial migration and the anoikis process. In this intravasation model, a tumor cell invasive mechanism was demonstrated (i) induction of extensive endothelial anoikis induced by degradation of the extracellular matrix (ECM) components, (ii) activation of pro-matrix metalloproteinase (MMP)-2 into MMP-2 by the MT1-MMP-TIMP (tissue inhibitor metalloproteinase) 2-pro-MMP-2 membrane complex and (iii) attraction and migration of metastatic cell through apoptotic endothelium. These interactions could partly explain the necrosis-angiogenesis relationship in tumor angiogenesis.

The effects of sodium phenylacetate (NaPa), an antitumoral molecule, on cell death and matrix metalloproteinase (MMP) activities and synthesis were investigated in two metastatic breast tumour cell lines, MDA-MB-231 and MDA-MB-435, cultured on three-dimensional type I collagen gels (3-D cultures). In both cell lines, NaPa inhibited cell proliferation and induced apoptotic cell death as measured by TUNEL assay, with an IC(30) of 20 mM and 10 mM for MDA-MB-231 and MDA-MB-435 cells, respectively. In MDA-MB-231 cells, NaPa also induced (i) an autophagic process evidenced by the appearance of autophagic vacuoles and an increased phosphatase acid activity, (ii) the formation of pseudopodia and (iii) an increase in MMP-1 and MMP-9 secretion without affecting MT1-MMP. In NaPa-treated MDA-MB-435 cells, no autophagic vacuoles were formed but F-actin depolymerisation was observed. MMP-1, MMP-9 and MT1-MMP levels were strongly enhanced in these cells but MMPs were not secreted and accumulated intracellularly. When breast cancer cells were treated with NaPa in the presence of an MMP inhibitor (GM6001), apoptotic cell death decreased and the induction of autophagic vacuoles in MDA-MB-231 cells was inhibited. Taken together, these data suggest that MMPs are involved in the autophagic cell death and/or apoptosis of breast tumour cells.

Background: Although there was growing evidence in the potential use of Bisphosphonates (BPs) in cancer therapy, their strong osseous affinities that contrast their poor soft tissue uptake limited their use. Here, we developed a new strategy to overcome BPs hydrophilicity by masking the phosphonic acid through organic protecting groups and introducing hydrophobic functions in the side chain., Methodology/principal Findings: We synthesized non-nitrogen BPs (non N-BPs) containing bromobenzyl group (BP7033Br) in their side chain that were symmetrically esterified with hydrophobic 4-methoxphenyl (BP7033BrALK) and assessed their effects on breast cancer estrogen-responsive cells (T47D, MCF-7) as well as on non responsive ones (SKBR3, MDA-MB-231 and its highly metastatic derived D3H2LN subclone). BP7033Br ALK was more efficient in inhibiting tumor cell proliferation, migration and survival when compared to BP7033Br. Although both compounds inhibited tumor growth without side effects, only BP7033Br ALK abrogated tumor angiogenesis and D3H2LN cells-induced metastases formation., Conclusion/significance: Taken together these data suggest the potential therapeutic use of this new class of esterified Bisphosphonates (BPs) in the treatment of tumor progression and metastasis without toxic adverse effects.

Objective: Few enzymes are able to attack the internal elastic lamina, which is destroyed in temporal arteritis (TA). Because human neutrophil elastase (HNE) is one of these, its role in the pathogenesis of TA was examined in patients undergoing temporal artery biopsy for suspected TA., Methods: Over a 6 month period, 33 patients undergoing temporal artery biopsy were prospectively included in the study. TA was diagnosed in 15 patients; 9 of them had positive temporal artery biopsy. The other 18 patients made up the non-TA group. Nineteen healthy age matched subjects (mean age 74 +/- 9 yrs) served as controls. Levels of plasma HNE bound to alpha1-antitrypsin (pHNE-alpha1AT) were measured by ELISA. The presence of HNE in the temporal artery wall of 7 TA and 7 non-TA patients was evaluated immunohistochemically., Results: Age, neutrophil counts, and erythrocyte sedimentation rates were similar in TA and non-TA patients. The mean pHNE-alpha1AT concentration in the TA group (84 +/- 20 microg/l) was significantly higher (p < 0.001) than in the non-TA group (51 +/- 26 microg/l) or in healthy controls (52 +/- 23 microg/l). The diagnostic sensitivity of pHNE-alpha1AT > 50 microg/l was 100%. Immunohistochemistry detected no HNE within the temporal artery wall of any patient., Conclusion: High levels of pHNE-alpha1AT were associated with TA. Our preliminary results indicate this could be a diagnostic marker for TA. Further studies are needed to confirm its reliability. Because HNE was not detected locally, no conclusions can be drawn as to its pathogenic role in TA.

Neonatal hemangioma is a common benign proliferation of unorganized structures containing stromal and capillary endothelial cells. We tested the hypothesis that such cell proliferation might result from the release by stromal cells of endothelial cell mitogens. Stromal cells cultured from biopsies of surgically removed life-threatening hemangiomas released an endothelial cell mitogen in vitro that was indistinguishable from vascular endothelial growth factor (VEGF) based on independent criteria such as affinity chromatography for heparin or anti-VEGF IgG and radioreceptor assay. A functional product of the KDR gene encoding a cognate VEGF receptor was also expressed by these stromal cells. Transient transfection with antisense oligonucleotides targeted on the translation initiation codon of KDR abolished its tyrosine phosphorylation and mitogenic response of neonatal hemangioma cells to VEGF, confirming the existence of an autocrine loop of proliferation. When grafted in nude mice, these stromal cells elicited an angiogenic response that was blocked by neutralizing anti-VEGF IgG. These results might provide a clue to the importance of stromal cells in the pathogeny of neonatal hemangiomas.

Thrombomodulin (TM), an endothelial receptor for thrombin, endowed with a powerful anticoagulant activity, plays an important role in the antithrombogenicity of the vascular endothelium. Its presence within the human renal glomerulus is already known but was thought to be only endothelial. We looked for TM expression in human mesangial cells (MC), both in situ, in freshly prepared glomeruli, and in primary culture. Both fresh and cultured MC were strongly reactive for TM by immunocytochemical methods. Total TM antigen measured on MC lysates and surface TM activity on MC were 0.292 +/- 0.075 ng/mg of cellular proteins and 1.20 +/- 0.02 pmole of activated protein C/min/mg of cellular proteins, respectively. As shown by the presence of numerous transcripts detected by in situ hybridization, TM was shown to be synthesized by MC in vivo and in culture. The synthesis of active TM by both endothelial and mesangial cells within the renal glomerulus stresses the importance of its role in maintaining renal hemostatic equilibrium, and sheds some light on the conflicting reports of TM over- and underexpression in glomerulopathies to open a new field for investigation.

Thrombomodulin, a major anticoagulant proteoglycan of the endothelial cell membrane, is a thrombin receptor that acts as a cofactor for protein C activation. It has previously been shown that thrombomodulin, present in human epidermis and in lysates of cultured keratinocytes, is implicated in cellular differentiation during mouse fetal development. The role of retinoic acid in keratinocyte differentiation prompted us to study retinoic acid regulation of thrombomodulin expression in primary cultures of keratinocytes isolated from adult human skin, grown at low (undifferentiated keratinocytes) and normal calcium levels (differentiated keratinocytes). Thrombomodulin antigen levels and total and surface activities were measured in cultures without and with retinoic acid. Thrombomodulin mRNA visualized by in situ hybridization was quantified by computer-based image analysis. Functional thrombomodulin was expressed on the surface and in the cytoplasm of cultured human keratinocytes regardless of the calcium concentration. In contrast, retinoic acid induced significant increases in the total antigen level and in surface and intracellular thrombomodulin activities only in keratinocytes grown in a low-calcium medium. In these undifferentiated keratinocytes, quantification of mRNA transcripts showed a threefold increase after retinoic acid stimulation. Thus, functional thrombomodulin is a human keratinocyte surface protein whose expression is controlled through the keratinocyte differentiation program and is modulated in vitro by retinoic acid.

Type IV collagenases are secreted as latent 92 and 72 kDa proenzymes which are then activated extracellularly. The mechanisms by which they are activated in vivo are not clear. We have studied the activation of porcine endothelial cell type IV collagenases by tissue and plasma kallikrein, and found that tissue kallikrein was a very efficient activator of the 92 kDa type IV collagenase. Enzyme cleavage was observed at concentrations of tissue kallikrein as low as 0.1 microgram/ml. Plasma kallikrein had no effect. By comparison, plasmin, which has been proposed to be the physiological activator of interstitial collagenase and stromelysin, and elastase were much less effective, and high concentrations (plasmin at 100-200 micrograms/ml and elastase at 20 micrograms/ml) were required to cause only a limited cleavage which was not associated with an increase in activity, as observed by the gelatin-gel lysis assay. In addition tissue kallikrein was found by immunohistochemistry to be present in the extracellular matrix of the intima of porcine aortic vessel wall. These findings suggest that tissue kallikrein can be a potential activator of the 92 kDa type IV collagenase in vivo.

Thrombomodulin (TM), a thrombin receptor, present on the endothelial surface of blood vessels is a major anticoagulant proteoglycan. In this work the presence of TM antigen in the human brain and in the whole central nervous system of calves was investigated by immunocytochemistry using specific antibodies against human and bovine TM. When TM antigen was well preserved by immediate fixation on frozen tissues, TM was found present in the brain vessels of all human surgical specimens examined as well as in the whole vasculature of the calf central nervous system (CNS), from the medulla to the cortex. Moreover, even without immediate fixation, TM antigen was always found on the surface of the cerebrospinal fluid (CSF) cavity: on the arachnoid and on the inner aspect of the dura mater in humans and in calves. This suggests that the proteolytic enzymes responsible for the cleavage of TM from the endothelium are not present in the CSF and in the meningeal cells. The results reported here emphasize the importance of TM in the CNS as protecting, by its antithrombogenicity, a free circulation of blood and CSF in normal and even more, in pathological situations in which the permeability of the meningeal barrier increases.

To determine the effect of the duration and severity of hypertension on arterial wall metabolism 28 enzyme activities and several macromolecular complexes were histochemically studied in normotensive (WK), moderately (SHR) and strongly hypertensive (SP-SHR) rats at various ages. The results indicate that the abnormalities of 5' nucleotidase, acid esterase, cholinesterase and Alk.P. appeared in prehypertensive 4 w.old SHR. The posthypertensive changes, fluctuating in relation to the duration of hypertension, concerned: the pentose pathway, Krebs cycle and glycolosis -linked dehydrogenases; lysosomal enzymes; glycogen-phosphorylase and MAO; glycosaminoglycan and glycoprotein content. The structural and metabolic response presented several local and regional differences. The metabolic changes were greater in the aorta than in the caudal and femoral arteries. The comparison between SHR and SP-SHR indicates that the blood pressure (BP) at 170 mm Hg seems well tolerated during a long period of time. Severe lesions such as degeneration and failure of lipolytic activity in aortic smooth muscle cells (SMC), notable and early (8 mo.) in SP-SHR with 240 mm Hg were less intense and appeared later (13 mo.) in SHR with 190 mm Hg. The level of hypertension, rather than its duration, appears as a determining factor of posthypertensive vascular damage.

48 rats were placed on an hyperlipidic diet (cholesterol, cholic acid, cholin, propylthiouracil), 23 were sacrificed at various intervals from the fourth up to the twelve month of the experiment. In the remaining 25 rats, the atherogenic regimen was replaced by a normal one. These animals were sacrificed one to twenty months after stopping of the experimental diet. Aortae of experimental and control animals were studied by means of histological and histochemical technics. All the animals developed hypercholesterolemia together with intima and media lipoidosis. None demonstrated any aortic cell proliferation. The only metabolic change of the smooth muscle cell was a progressive decrease in 5' nucleotidase, acid esterase and cholinesterase activities. The return to a normal diet involved the reversion of the serum cholesterol level to normal values and the disappearance of intima lipoidosis. The reduced enzymatic activities in the media returned to normal levels around the sixth month. The surfaces of the extracellular sudanophilic areas decreased. However, twenty months after stopping of the atherogenic diet, some lipids still persisted at the edges of the elastic fibres.

The histological, ultrastructural and permeability aspects of the intima in 60 70-week-old spontaneously hypertensive (SHR) and Wistar Kyoto normotensive (WK) rats were studied and compared. The intima of aorta, coronary and renal arteries was unequally thickened owing to the smooth muscle cell (SMC) migration and proliferation, blood cell immigration and endothelial cell activation. The present work describes intimal changes that may act as potential atherogenic factors, i.e. hyper-reactivity of endothelial cells; decreased thinness of endothelial cell periphery; reduced intercellular junction pathways; increased quantity of basement lamina and glycosaminoglycan subendothelial material; platelet and monocyte-macrophage infiltration; widened fenestrae in the internal elastic lamina, and smooth muscle cell migration and proliferation. These changes might possibly be able to reduce the atheroresistance of this species by reducing the barrier function, increasing the trapping effect and stimulating smooth muscle cell proliferation and fibrogenesis. They are believed to promote the development of arterial lipidosis when hyperlipemia is an added risk factor.

48 rats were placed on an hyperlipidic diet (cholesterol, cholic acid, cholin, propylthiouracil), 23 were sacrificed at various intervals from the fourth up to the twelve month of the experiment. In the remaining 25 rats, the atherogenic regimen was replaced by a normal one. These animals were sacrificed one to twenty months after the withdrawal of the experimental diet. Aortae of experimental and control animals were studied by means of histological and histochemical technics. All the animals developed hypercholesterolemia together with intima and media lipoidosis. None demonstrated any aortic cell proliferation. The only metabolic change of the smooth muscle cell was a progressive decrease in 5' nucleotidase, acid esterase and cholinesterase activities. The return to a normal diet involved the reversion of the serum cholesterol level to normal values and the disappearance of intima lipoidosis. The reduced enzymatic activities in the media returned to normal levels around the six month. The surfaces of the extracellular sudanophilic areas decreased. However, twenty months after the withdrawal of the atherogenic diet, some lipids still persisted at the edges of the elastic fibres.

Twenty-seven enzyme activities and five macromolecular complexes in central and peripheral arteries of the spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) 4, 20, 30 and 60 week-old rats were comparatively studied. Some of the four-week-old SHR (prehypertensive stage) showed several enzyme-cytochemical differences in comparison with WKY of the same age. In the adult SHR (20 to 60 weeks), the metabolic behaviour of different arterial segments was not uniform. Thus, the arteriopathy of elastic-type arteries was reflected by early and permanent activation of 5' nucleotidase and by the early increase (between 5 and 30 weeks) and later decrease (60th week) of esterase-and cholinesterase-activity. Peripheral arteriopathy was evidenced by hyperactivity and/or hypoactivity of glycogen-synthetase, glycogen-phosphorylase and monamine oxidase (in muscular-type arteries) and by early (5th week) and long lasting (60th week) hyperactivity of alcaline phosphatase (in arterioles). Some parameters were modified throughout the whole vasculature: increase in RNA, glycosaminoglycans, and glycoproteins, heightened lysosomal and dehydrogenase enzyme activities. Certain reported chemical modifications are discussed in connection with atherogenesis (carboxylic esterases and glycosaminoglycans) and peripheral tensiogenesis (5' nucleotidase, alcaline phosphatase, L-amino-peptidase, MAO).