Antibodies blocking adhesion and matrix binding domains of laminin-332 inhibit tumor growth and metastasis in vivo.
ABSTRACT Laminin-332 (LN-332), which is essential for epithelial cell adhesion and migration, is up-regulated in most invasive carcinomas. Association between LN-332 and carcinoma cell integrins and stroma collagen is thought to be important for tumor growth and metastasis. Here, we show that function blocking LN-332 antibodies interfering with cellular adhesion and migration in vitro evoke apoptotic pathways. The antibodies also target epithelial tumors in vivo. Antibodies against the cell binding domain of the alpha3 chain of LN-332 inhibited tumor growth by up to 68%, and antibodies against the matrix binding domains of the beta3 and gamma2 chains significantly decreased lung metastases. The LN-332 antibodies appear to induce tumor cell anoikis and subsequent programmed cell death and reduce migration by interfering with tumor cell matrix interactions.
Article: Lamellipodia in invasion[show abstract] [hide abstract]
ABSTRACT: In vivo imaging of GFP-labeled metastatic tumor cells reveals cell orientation towards blood vessels. Orientation of tumor cells during chemotactic responses to ligands such as EGF begins with lamellipod extension. Evaluation of some of the downstream events in lamellipod extension indicates: (1) plasma membrane distribution of the EGF receptor is uniform but internalized receptor accumulates on the side of the cell closest to the source of EGF; (2) the alpha p110 isoform of PI-3 kinase is required; and (3) protrusion of the lamellipod relies upon the combined actions of the Arp2/3 complex and cofilin for generation of filamentous actin.Seminars in Cancer Biology 05/2001; · 7.44 Impact Factor
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ABSTRACT: Cutaneous basement membrane zone (BMZ) consists of a number of attachment structures that are critical for stable association of the epidermis to the underlying dermis. These include hemidesmosomes, anchoring filaments and anchoring fibrils which form an interconnecting network extending from the intracellular milieu of basal keratinocytes across the dermal-epidermal basement membrane to the underlying dermis. Aberrations in this network structure, e.g. due to genetic lesions in the corresponding genes, can result in fragility of the skin at the level of the cutaneous BMZ. The prototype of such diseases is epidermolysis bullosa (EB), a heterogeneous group of genodermatoses characterized by fragility and blistering of the skin, often associated with extracutaneous manifestations, and inherited either in an autosomal dominant or autosomal recessive manner. Based on constellations of the phenotypic manifestations, severity of the disease, and the level of tissue separation within the cutaneous BMZ, EB has been divided into clinically distinct subcategories, including the simplex, hemidesmosomal, junctional and dystrophic variants. Elucidation of BMZ gene/protein systems and development of mutation detection strategies have allowed identification of mutations in 10 different BMZ genes which can explain the clinical heterogeneity of EB. These include mutations in the type VII collagen gene (COL7A1) in the dystrophic (severely scarring) forms of EB; mutations in the laminin 5 genes (LAMA3, LAMB3 and LAMC2) in a lethal (Herlitz) variant of junctional EB; aberrations in the type XVII collagen gene (COL17A1) in non-lethal forms of junctional EB; mutations in the alpha6 and beta4 integrin genes in a distinct hemidesmosomal variant of EB with congenital pyloric atresia; and mutations in the plectin gene (PLEC1) in a form of EB associated with late-onset muscular dystrophy. Identification of mutations in these gene/protein systems attests to their critical importance in the overall stability of the cutaneous BMZ. Furthermore, elucidation of mutations in different variants of EB has direct clinical applications in terms of refined classification, improved genetic counseling, and development of DNA-based prenatal testing in families with EB.Matrix Biology 03/1999; 18(1):29-42. · 3.19 Impact Factor
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ABSTRACT: Epithelial cell-specific laminin-5, consisting of three chains, alpha3, beta3, and gamma2, is a component of the anchoring filament that traverses the lamina lucida beneath the hemidesmosomes of epidermal cells and functions to link these cells to the basement membrane. We have studied the molecular interaction between laminin-5 and extracellular matrix proteins using recombinant proteins and synthetic peptides. Affinity chromatography assays with recombinant fragments of the laminin gamma2 short arm identified a 195-kDa binding protein in the conditioned media from the mouse epidermal cell line Pam 212 and from primary dermal fibroblasts. This molecule was identified by Western blotting as fibulin-2, a recently identified extracellular matrix protein. Using deletion mutants and various synthetic peptides in competition assays, the 9-amino acid sequence SADFSVHKI (residues 199-207) in domain IV of the gamma2 chain was defined as a critical site for fibulin-2 binding. An anti-gamma2 antibody co-immunoprecipitated fibulin-2 from the conditioned media, further confirming the interaction of fibulin-2 with laminin-5. Fibulin-2 was also found to interact with laminin-1 (alpha1beta1gamma1) through a region (residues 654-665) of the alpha1 chain short arm whose sequence is similar to that of the fibulin-2 binding site of the gamma2 chain. Together these results suggest that fibulin-2 functions to bridge laminin-1 and laminin-5 with other extracellular matrix proteins, providing a linkage between the cell surface and the basement membrane.Journal of Biological Chemistry 02/1997; 272(5):2814-20. · 4.65 Impact Factor