| 1. |
- Genersch, Elke, et al.
(författare)
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Integrin alphavbeta3 binding to human alpha5-laminins facilitates FGF-2- and VEGF-induced proliferation of human ECV304 carcinoma cells.
- 2003
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Ingår i: European Journal of Cell Biology. - : Elsevier BV. - 0171-9335. ; 82:3, s. 105-117
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Tidskriftsartikel (refereegranskat)abstract
- Human ECV304 cells respond reproducibly by tube formation to complex basement membrane matrices. Laminins are major glycoproteins of basement membranes. We therefore studied the ability of ECV304 cells to attach to defined laminin isoforms and to fibronectin, and identified the involved laminin receptors. The cells bound poorly to fibronectin, to some extent to laminin-1, whereas laminin-2/4 and -10/11 were strong adhesive substrates. Antibody perturbation assays showed that adhesion to laminin-1 was mediated by integrin α6β1, and adhesion to laminin-2/4 by cooperative activity of integrins α3β1 and α6β1. Adhesion of ECV 304 cells to laminin-10/11 was mainly mediated by integrins α3β1, with minor involvement of α6β1/4 and αvβ3. Solid-phase binding assays confirmed that integrin αvβ3 binds human laminin-10/11 and -10, in an RGD-dependent fashion. Although integrin αvβ3 played a very minor role in cell adhesion to laminin-10/11, this interaction facilitated growth factor-induced proliferation of ECV304 cells. In response to FGF-2 or VEGF, the cells proliferated better when attached on laminin-10/11 than on laminin-1, -2/4, or gelatin. The proliferation induced by the joint application of laminin-10/11 and either one of the growth factors could be blocked by antibodies against integrin αvβ3. Fragments of several other basement membrane components are known to interact with αvβ3. The current data show that that integrin αvβ3 can bind intact α5-containing laminin trimers. Since the laminin α5 chain is broadly expressed in adult basement membranes, this interaction could be physiologically important. Our data suggest that this interaction is involved in the regulation of cellular responses to growth factors known to be involved in epithelial and endothelial development.
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| 2. |
- Khazenzon, Natalya M, et al.
(författare)
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Antisense inhibition of laminin-8 expression reduces invasion of human gliomas in vitro
- 2003
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Ingår i: Molecular Cancer Therapeutics. - 1538-8514. ; 2:10, s. 985-994
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Tidskriftsartikel (refereegranskat)abstract
- Using gene array technology, we recently observed for the first time an up-regulation of laminin alpha4 chain in human gliomas. The data were validated by semiquantitative reverse transcription-PCR for RNA expression and immunohistochemistry for protein expression. Moreover, increase of the alpha4 chain-containing laminin-8 correlated with poor prognosis for patients with brain gliomas. Therefore, we hypothesized that inhibition of laminin-8 expression by a new generation of highly specific and stable antisense oligonucleotides (Morpholino) against chains of laminin-8 could slow or stop the spread of glioma and its recurrence and thus might be a promising approach for glioma therapy. We next sought to establish an in vitro model to test the feasibility of this approach and to optimize conditions for Morpholino treatment. To develop a model, we used human glioblastoma multiforme cell lines M059K and U-87MG cocultured with normal human brain microvascular endothelial cells (HBMVEC). Using Western blot analysis and immunohistochemistry, we confirmed that antisense treatment effectively blocked laminin-8 protein synthesis. Antisense oligonucleotides against both alpha4 and beta1 chains of laminin-8 were able to block significantly the invasion of cocultures through Matrigel. On average, the invasion was blocked by 62% in cocultures of U-87MG with HBMVEC and by 53% in cocultures of M059K with HBMVEC. The results show that laminin-8 may contribute to glioma progression and recurrence not only as part of the neovascularization process but also by directly increasing the invasive potential of tumor cells.
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| 3. |
- Kjellgren, Daniel, et al.
(författare)
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Laminin isoforms in human extraocular muscles
- 2004
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Ingår i: Investigative Ophthalmology and Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 0146-0404 .- 1552-5783. ; 45:12, s. 4233-4239
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To determine the laminin isoform composition of the basement membranes (BMs) in the human extraocular muscles (EOMs) and relate it to the fact that EOMs are spared in laminin alpha2-chain-deficient congenital muscular dystrophy. METHODS: Samples from adult human EOMs and limb muscle were processed for immunocytochemistry, with monoclonal antibodies against laminin chains (Ln) alpha1 to -5, beta1 and -2, and gamma1. Neuromuscular junctions (NMJs) were identified with acetylcholinesterase reaction. The capillary density was measured in sections stained with anti-Lnalpha5. RESULTS: The extrasynaptic BM of the EOM muscle fibers contained Lnalpha2, -beta1, -beta2, and -gamma1, and, in contrast to limb muscle, it also contained Lnalpha4 and -alpha5, to some extent. The distinct laminin composition of the EOMs was confirmed by the presence of Lutheran protein, an alpha5-chain-specific receptor not found in limb muscle. At the NMJs, there was increased expression of Lnalpha4 and expression of Lnalpha2, -alpha5, -beta1, -beta2, and -gamma1 was also maintained. The capillary density was very high (1050 +/- 190 capillaries/mm(2)) in the EOMs and significantly (P < 0.05) higher in the orbital (1170 +/- 180 capillaries/mm(2)) than in the global (930 +/- 110 capillaries/mm(2)) layer. CONCLUSIONS: The human EOMs showed important differences in laminin isoform composition and capillary density when compared with human limb muscle and muscles of other species. The presence of additional laminin isoforms other than laminin-2 in the BM of the extrasynaptic sarcolemma could partly explain the sparing of the EOMs in Lnalpha2-deficient congenital muscular dystrophy.
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| 4. |
- Petrova, Tatiana V, et al.
(författare)
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Lymphatic endothelial reprogramming of vascular endothelial cells by the Prox-1 homeobox transcription factor.
- 2002
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Ingår i: EMBO Journal. - 0261-4189 .- 1460-2075. ; 21:17
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Tidskriftsartikel (refereegranskat)abstract
- Lymphatic vessels are essential for fluid homeostasis, immune surveillance and fat adsorption, and also serve as a major route for tumor metastasis in many types of cancer. We found that isolated human primary lymphatic and blood vascular endothelial cells (LECs and BECs, respectively) show interesting differences in gene expression relevant for their distinct functions in vivo. Although these phenotypes are stable in vitro and in vivo, overexpression of the homeobox transcription factor Prox-1 in the BECs was capable of inducing LEC-specific gene transcription in the BECs, and, surprisingly, Prox-1 suppressed the expression of approximately 40% of the BEC-specific genes. Prox-1 did not have global effects on the expression of LEC-specific genes in other cell types, except that it up-regulated cyclin E1 and E2 mRNAs and activated the cyclin e promoter in various cell types. These data suggest that Prox-1 acts as a cell proliferation inducer and a fate determination factor for the LECs. Furthermore, the data provide insights into the phenotypic diversity of endothelial cells and into the possibility of transcriptional reprogramming of differentiated endothelial cells.
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| 5. |
- Petäjäniemi, Noora, et al.
(författare)
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Localization of laminin alpha4-chain in developing and adult human tissues
- 2002
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Ingår i: Journal of Histochemistry and Cytochemistry. - : SAGE Publications. - 0022-1554 .- 1551-5044. ; 50:8, s. 1113-1130
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies suggest important functions for laminin-8 (Ln-8; alpha4beta1gamma1) in vascular and blood cell biology, but its distribution in human tissues has remained elusive. We have raised a monoclonal antibody (MAb) FC10, and by enzyme-linked immunoassay (EIA) and Western blotting techniques we show that it recognizes the human Ln alpha4-chain. Immunoreactivity for the Ln alpha4-chain was localized in tissues of mesodermal origin, such as basement membranes (BMs) of endothelia, adipocytes, and skeletal, smooth, and cardiac muscle cells. In addition, the Ln alpha4-chain was found in regions of some epithelial BMs, including epidermis, salivary glands, pancreas, esophageal and gastric glands, intestinal crypts, and some renal medullary tubules. Developmental differences in the distribution of Ln alpha4-chain were detected in skeletal muscle, walls of vessels, and intestinal crypts. Ln alpha4- and Ln alpha2-chains co-localized in BMs of fetal skeletal muscle cells and in some epithelial BMs, e.g., in gastric glands and acini of pancreas. Cultured human pulmonary artery endothelial (HPAE) cells produced Ln alpha4-chain as M(r) 180,000 and 200,000 doublet and rapidly deposited it to the growth substratum. In cell-free extracellular matrices of human kidney and lung, Ln alpha4-chain was found as M(r) 180,000 protein.
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| 6. |
- Virtanen, Ismo, et al.
(författare)
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Laminin isoforms in fetal and adult human adrenal cortex
- 2003
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 88:10, s. 4960-4966
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Tidskriftsartikel (refereegranskat)abstract
- Laminin has been proposed to influence the function of human adrenal cortex. We have studied the distribution of laminin (Ln) chains using immunofluorescence in human fetal and adult adrenal cortex. In the fetal gland Ln alpha2- and alpha5-chains were weakly expressed in the definitive zone, whereas Ln alpha4-, beta1-, and gamma1-chains occurred around vessels. In the adult gland, Ln alpha2-, alpha5-, and gamma1-chains were found in epithelial basement membranes (BM) in all cortical zones, Ln alpha4-chain in vessels, Ln beta1-chain in outer zone, and Ln beta2-chain in the two inner zones of the cortex, respectively. Among the integrins in adult gland, integrin alpha(3)-subunit was confined to basal surfaces of cortical cells, alpha(6) to vessels, alpha(1) to the stroma, and alpha(2) diffusely to epithelial cells. Lutheran glycoprotein and dystroglycan occurred in the fetal gland diffusely in the definitive zone and throughout the epithelium in the adult. The isoform composition of BM of the adult adrenal gland is distinct, with Ln-2 and -10 in BM of the outer zone and Ln-4 and -11 in BM of the two inner zones. The results suggest that integrin alpha(3)beta(1) and Lutheran are candidate receptors for Ln-10 and -11, whereas dystroglycan probably binds Ln-2 and -4.
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