Differential inhibition of renal cancer cell invasion mediated by fibronectin, collagen IV and laminin

Invasion of tumor cells into the extracellular matrix is an essential step in the formation of metastases in renal cancer. Cell adhesion molecules such as β1-integrins, which bind to the RGD sequence (arginine-glycine-asparagine) and CD44 are involved in this process. We examined the invasion of a renal carcinoma cell line (CCF-RC1) into the extracellular matrix compounds fibronectin, collagen IV and laminin and the effect of TGFβ and IFNγ on this process. The inhibitory effect of an antibody against the β1-subunit of integrins (CD29), as well as a pentapeptide including the RGD sequence, was also evaluated. A micro-chemotaxis chamber, including a polycarbonate membrane with a pore diameter of 8 μm, was used for quantification of cell migration. The addition of the extracellular matrix compounds fibronectin, laminin and collagen IV resulted in a 5–10-fold increase in invasion. This increased invasion depends strongly on the presence of β1-integrins, shown by the use of an antibody against CD29 or a RGD including peptide which inhibit the cell migration by approximately 88%. CD44 is less involved in collagen IV dependent migration and almost no influence of CD44 was observed on a fibronectin and laminin dependent migration. TNFα and IFNγ did not significantly influence the expression of CD29 or CD44, and no alteration in tumor cell migration was observed. These results show that the invasion of renal cancer cells is differentially regulated by compounds of the extracellular matrix, whereby fibronectin seems to be the most critical factor. The molecular interactions in this process are strongly dependent on β1-integrins and the corresponding amino acid sequence RGD.