Differential response of cultured mammalian cells to cytochalasin B in multinucleation.

Cytochalasin B (CB) was applied to 13 kinds of non-tumorigenic or tumorigenic cells in vitro to investigate whether the drug would be applicable as an indicator to identify the transformation of cells. Normal cell strains suffered from more deteriorative changes in morphology than cell lines, showing arborization of their cytoplasm at 5 mug/ml. CB at 2.5 mug/ml consistently prevented cytoplasmic cleavage without interfering with nuclear division. Multinucleation of the cells exposed to CB was not related to their generation time. The correlation between multinucleation and tumorigenicity of the cells was found with some exceptions. It appears, however, that multinucleation induced by CB would not be a reliable parameter for identifying malignant transformation of cells in vitro.