Effects of laminin on attachment, growth and differentiation of cultured Y-79 retinoblastoma cells.

In vitro, as in vivo, the attachment, growth and differentiation of many cell types are dependent upon the availability of appropriate extracellular matrix (ECM) molecules. Here we have studied the effects of ECM components, including fibronectin and laminin on cultured Y-79 retinoblastoma cells. Both in 2 hr and in 3 day studies, the highest frequencies of attachment were seen with a laminin substrate (50 micrograms/35 mm culture dish). Attachment was significantly inhibited by specific anti-laminin antibodies. In longer studies of up to 1 week, laminin or fibronectin was added directly to the culture medium. Neither molecule significantly stimulated cell growth, but laminin continued to promote the highest frequencies of attachment (20% to 30% greater than any other substrate). Laminin exposure also caused morphological changes in Y-79 cells. Many cells became flattened and extended long, branching, neurite-like processes. These changes could be inhibited by inclusion of anti-laminin antibodies. Such studies may provide information about events occurring during normal eye development as well as about tumor cell attachment and growth.