Abstract
The presence of fibronectin in three “malignant” (AU‐471, AU‐436, LT‐2) and two “benign” (BHK‐21, WI‐38) cell lines was demonstrated with a fluorescent antibody technique; two malignant (AU‐471, AU‐436) cell lines were fibronectin‐negative and one (LT‐2) retained fibronectin expression. One “benign” cell line (WI‐38) expressed fibronectin, the other (BHK‐21) did not. Anchorage‐independent soft agar (AISA) growth correlated better with loss of fibronectin than with malignant potential. All three fibronectin‐negative cell lines (benign and malignant) grew anchorage‐independently (AU‐471, AU‐436, BHK‐21), and both fibronectin‐positive cell lines were anchorage‐dependent (LT‐2, WI‐38). Surprisingly, the addition of Clg to anchorage‐independent cells increased their anchorage‐independent soft‐agar cloning efficiency, but had no effect on anchorage‐dependent cell lines. Anti‐Clg antibodies decreased AISA growth. The effect of Clg on anchorage‐independent growth varied with the concentration, and also between cell lines, and a variation in effect was noted between anchorage‐independent (AISA) and anchorage‐dependent (in flasks) growth even in the same cell line.