Integrin alpha 2 beta 1 is upregulated in fibroblasts and highly aggressive melanoma cells in three-dimensional collagen lattices and mediates the reorganization of collagen I fibrils.

The ability of cultured human fibroblasts to reorganize and contract three dimensional collagen I gels is regarded as an in vitro model for the reorganization of connective tissue during wound healing. We investigated whether adhesion receptors of the integrin family are involved. It was found that synthesis and transcription of the alpha 2 beta 1 integrin (but not of alpha 1 beta 1 or alpha 3 beta 1) is selectively upregulated when fibroblasts are seeded into type I collagen gels.

Identification of a melanoma progression antigen as integrin VLA-2.

The expression of the integrin receptors VLA-1, -2, -3, and -6 was studied in normal cultured melanocytes and in five melanoma cell lines. Normal melanocytes synthesized VLA-3, but did not reveal detectable levels of VLA-1, -2, and -6. All melanoma cell lines, however, expressed VLA-2, -3, and -6.

Integrins of normal human epidermis: differential expression, synthesis and molecular structure.

The expression of integrin cell surface receptors in normal skin and their synthesis and molecular structure in keratinocyte cultures was investigated. The reactivity of four different polypeptides of the integrin family (alpha 2-, alpha 3-, alpha 6- and beta 1-chains) was demonstrated in the basal cell layer of normal epidermis. Studies of labelled keratinocyte cell lines showed that the polypeptides were expressed as alpha 2 beta 1, alpha 3 beta 1 and alpha 6 beta 4 integrins.

Cooperation of SV40 large T antigen and the cellular protein p53 in maintenance of cell transformation.

We analysed large T antigen expression and metabolic stabilisation of the cellular protein p53 in cells of a matched pair of SV40 tsA mutant (tsA58) N-type or A-type transformants, respectively. At the permissive growth temperature (32 degrees C), cells of both transformants, like SV40 wild-type transformed cells, were phenotypically transformed and expressed large T antigen, as well as metabolically stable p53 (both complexed and free p53). At the nonpermissive growth temperature (39 degrees C), cells of the N-type transformant reverted to a normal phenotype, whereas cells of the A-type transformant still displayed a transformed phenotype.