Differences in adhesion to tissue culture plastic of clonally related transformed and control sublines from an epithelial cell strain

Clonally related sublines of the NAL1A lung epithelial cell strain were used in a comparison of the mechanism of attachment and the morphology of control and transformed epithelial cells. The initial attachment and spreading of the control cells on tissue culture plastic was shown to be dependent upon adsorption of serum vitronectin to the substratum. The alpha v subunit of the vitronectin receptor was detected in both the control and transformed cells by immunoprecipitation and immunoblot methods. The spontaneously transformed cells differed from the control cells in that, whereas attachment to tissue culture plastic could occur by binding to adsorbed vitronectin, the transformed cells could also become attached, with time, by a vitronectin-independent mechanism. Attachment by this vitronectin-independent reaction was inhibited by the protein synthesis inhibitor cycloheximide and also by the microtubule-disrupting drugs demicolcemid and nocodazole. The morphologies of attached control and transformed cells cultured on tissue culture plastic were disrupted by treatment with cytochalasin B, demicolcemid or nocodazole, indicating that the shape of these cultured epithelial cells is dependent upon the microtubule system as well as the actin filaments. These results show one important difference between the control and transformed cells, in that the transformed cells can attach to tissue culture plastic by a vitronectin-independent mechanism that involves new protein synthesis by the cell. Another interesting difference is that this vitronectin-independent attachment of the transformed cells was sensitive to inhibition by microtubule-disrupting agents. On the other hand, the attachment of either transformed or control cells to fibronectin- or vitronectin-coated surfaces was not affected by microtubule-disrupting agents.