Expression of laminin by human fibroblasts, HT1080 fibrosarcoma cells and MCF-7 breast adenocarcinoma cells. Lack of regulation by the cell density and extracellular matrix.

We have cultured normal fibroblasts, fibrosarcoma HT1080 cells and breast adenocarcinoma MCF-7 cells on various substrates (plastic, collagen type I, laminin). All cell types used adhered on the three substrates with, however, a delayed attachment on laminin. On all substrates, cell grew as monolayer with the exception of MCF-7 cells that formed clusters on laminin. The epithelial MCF-7 cells as well as mesenchymal cells (fibroblasts and tumoral HT1080 cells) synthesized laminin and expressed mRNA coding for laminin B1 chain and for the 67 kD laminin binding protein. The levels of these mRNAs were not modulated by culture conditions which affect cell morphology nor by cell density.