Multinucleation of transformed cells normalizes their spreading on the substratum and their cytoskeleton structure.

Transformed mouse fibroblasts of L line and cells of their highly oncogenic TLSF subline are deficiently spread on the solid substratum, do not form focal contacts with it and do not contain microfilament bundles. Polykaryons were produced from these cells by polyethylene glycol-induced cell fusion or by cytochalasin B-induced block of cytokinesis. Multinuclear cells obtained by both methods were much better spread on the substrate than their mononuclear counterparts. Most of the polykaryons have numerous actin microfilament bundles and form focal contacts with substratum. Therefore, multinucleation of transformed results in their partial morphological normalization.