The functions of laminins: Lessons from in vivo studies

Ryan, Maureen C.; Christiano, Angela M.

doi:10.1016/s0945-053x(96)90157-2

Cited by 134 publications

(93 citation statements)

References 63 publications

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“…The α1 chain together with the β1 and γ1 chains forms the prototypic EHS laminin (laminin-1) and is expressed in different BMs (Ryan et al, 1996). Nevertheless, we were unable, however, to detect the laminin α1 chain in embryonal, normal adult, hyperand dysplastic or carcinomatous epithelial BM using a polyclonal antibody.…”

Section: Laminin Chains In the Normal Oral Squamous Epitheliummentioning

confidence: 77%

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma

et al. 1999

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SummaryThe expression of laminin and fibronectin isoforms varies with cellular maturation and differentiation and these differences may well influence cellular processes such as adhesion and motility. The basement membrane (BM) of fetal oral squamous epithelium contains the laminin chains, α2, α3, α5, β1, β2, β3, γ1 and γ2. The BM of adult normal oral squamous epithelium comprises the laminin chains, α3, α5, β1, β3, γ1 and γ2. A re-expression of the laminin α2 and β2 chains could be shown in adult hyperproliferative, dysplastic and carcinomatous lesions.In dysplasia and oral squamous cell carcinoma (OSCC), multifocal breaks of the BM are present as indicated by laminin chain antibodies. These breaks correlate to malignancy grade in their extent. Moreover, in the invasion front the α3 and γ2 chain of laminin-5 can immunohistochemically be found outside the BM within the cytoplasm of budding carcinoma cells and in the adjacent stroma. The correlation between the morphological pattern of invasive tumour clusters and a laminin-5 immunostaining in the adjacent stroma may suggest, first, that a laminin-5 deposition outside the BM is an immunohistochemical marker for invasion and second, that OSCC invasion is guided by the laminin-5 matrix. Expression of oncofetal fibronectins (IIICS de novo glycosylated fibronectin and ED-B fibronectin) could be demonstrated throughout the stromal compartment. However, the ED-B fibronectin synthesizing cells (RNA/RNA in situ hybridization) are confined to small stroma areas and to single stroma and inflammatory cells in the invasion front. A correlation of the number of ED-B fibronectin synthesizing cells to malignancy grade could not be seen. ED-B fibronectin mRNA-positive cells seem to be concentrated in areas of fibrous stroma recruitment with a linear alignment of stromal fibro-/myofibroblasts (desmoplasia). Double staining experiments (ED-B fibronectin in situ hybridization and α-smooth muscle actin immunohistochemistry) indicated that the stroma myofibroblasts are a preferential source of ED-B fibronectin. In conclusion, in OSCC, a fetal extracellular matrix conversion is demonstrable. Tumour cells (laminin α2 and β2 chain) and recruited stromal myofibroblasts (oncofetal ED-B fibronectin) contribute to the fetal extracellular matrix milieu.

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Section: Laminin Chains In the Normal Oral Squamous Epitheliummentioning

confidence: 77%

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma

et al. 1999

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“…Laminin-332 (previously known as laminin-5), which comprises a3, b3 and g2 chains, is a major component of epithelial BM, acts as an adhesion substrate for the epithelial cells and regulates epithelial cell migration during epithelial regeneration and repair processes in normal tissues (Carter et al, 1991;Rousselle et al, 1991;Ryan et al, 1996). Laminin-332 interacts with two major epithelial integrin a3b1 and a6b4, and promotes the formation of two separate types of attachment structure, focal adhesion and stable anchoring contacts (Carter et al, 1990).…”

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confidence: 99%

Laminin-332 promotes the invasion of oesophageal squamous cell carcinoma via PI3K activation

et al. 2008

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Laminin-332 is major component of epithelial basement membrane, and has an important role in cell migration and tumour invasion. Recently, the phosphatidylinositol 3-kinase (PI3K) activation induced by laminin-332 during carcinogenesis or tumour invasion has been highlighted in skin squamous cell carcinoma. The expression of laminin-332 in 126 resected oesophageal squamous cell carcinoma (ESCC) specimens was immunohistochemically examined to determine its associations with the clinicopathological characteristics, and the effect of laminin-332 on the invasiveness and the PI3K activation was assessed by in vitro experiments using ESCC cell lines (ESCCs). Sections with immunostaining signals in 430% cancer cells, which were observed in 55 of 126 cases, were judged to be positive for laminin-332. The positivity was significantly correlated with pTNM stage and poor prognosis. Inactivation of the PI3K pathway by laminin-332 blocking antibody suppressed the invasiveness of TE8 cell line, which secreted laminin-332 at high level and had high PI3K activity. The addition of the purified laminin-332 activated the PI3K pathway and increased the invasiveness of TE11 cell line, which secreted laminin-332 at lower level and had low PI3K activity. The deactivation of PI3K pathway using the PI3K inhibitor decreased the invasiveness of ESCCs and the secretion of laminin-332 in vitro. The expression of laminin-332 was one of the prognostic factors of ESCC. Laminin-332 could provide the autocrine positive-feedback loop through PI3K activation, contributing the invasive ability. Therefore, the inhibitor of PI3K pathway might be useful as the anticancer therapies for ESCC.

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“…The laminins are a family of abundant and essential basement membrane proteins implicated in numerous processes important to normal tissue development and homeostasis (1,2). The prototypical laminin is a large, disulfide-linked heterotrimer consisting of ␣, ␤, and ␥ chains (1,2).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

“…The prototypical laminin is a large, disulfide-linked heterotrimer consisting of ␣, ␤, and ␥ chains (1,2). Multiple isoforms for each chain have been identified, giving rise to numerous heterotrimer combinations with great potential for functional diversity/specificity (1,2). In normal adult skeletal muscle, for example, laminin-2 (␣2␤1␥1), colloquially known as merosin, is expressed predominantly throughout the basement membrane (3,4).…”

mentioning

confidence: 99%

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Differential Heparin Sensitivity of α-Dystroglycan Binding to Laminins Expressed in Normal and dy/dy Mouse Skeletal Muscle

McDearmon

Burwell

Combs

et al. 1998

Journal of Biological Chemistry

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The ␣-dystroglycan binding properties of laminins extracted from fully differentiated skeletal muscle were characterized. We observed that the laminins expressed predominantly in normal adult rat or mouse skeletal muscle bound ␣-dystroglycan in a Ca 2؉ -dependent, ionic strength-sensitive, but heparin-insensitive manner as we had observed previously with purified placental merosin (Pall, E. A., Bolton, K. M., and Ervasti, J. M. 1996 J. Biol. Chem. 271, 3817-3821). Rat skeletal muscle laminins partially purified by heparin-agarose affinity chromatography also bound ␣-dystroglycan without sensitivity to heparin. We also confirm previous studies of dystrophic dy/dy mouse skeletal muscle showing that the ␣2 chain of merosin is reduced markedly and that the laminin ␣1 chain is not up-regulated detectably. However, we further observed a quantitative decrease in the expression of laminin ␤/␥ chain immunoreactivity in ␣2 chain-deficient dy/dy skeletal muscle and reduced ␣-dystroglycan binding activity in laminin extracts from dy/dy muscle. Most interestingly, the ␣-dystroglycan binding activity of residual laminins expressed in merosin-deficient dy/dy skeletal muscle was inhibited dramatically (69 ؎ 19%) by heparin. These results identify a potentially important biochemical difference between the laminins expressed in normal and dy/dy skeletal muscle which may provide a molecular basis for the inability of other laminin variants to compensate fully for the deficiency of merosin in some forms of muscular dystrophy.

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The functions of laminins: Lessons from in vivo studies

Cited by 134 publications

References 63 publications

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma

Distribution of laminin and fibronectin isoforms in oral mucosa and oral squamous cell carcinoma

Laminin-332 promotes the invasion of oesophageal squamous cell carcinoma via PI3K activation

Differential Heparin Sensitivity of α-Dystroglycan Binding to Laminins Expressed in Normal and dy/dy Mouse Skeletal Muscle

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