Ultrastructural and enzymic modulation of HeLa cells induced by sodium butyrate and the effects of cytochalasin B and colcemid.

Sodium butyrate causes HeLa cells to assume an elongated and jagged shape. Ultrastructurally this change is associated with the formation of bundles of microfilaments. Desmosomes were present between adjacent cells. No increase in microtubules was observed in the butyrate-treated cells. Butyrate induces an increase in the activity of 2 membrane-bound enzymes, alkaline phosphatase and 5'-nucleotidase; however, the activity of a third membrane enzyme, acetylcholine esterase, is reduced. The activities of the several other enzymes with different subcellular localizations are not significantly increased. Colcemid and cytochalasin B prevent or reverse the butyrate-mediated change in HeLa cell morphology and also partially inhibit the induction of alkaline phosphatase activity in these cells. The effect of cytochalasin B on alkaline phosphatase induction may be caused by a reduction in protein synthesis produced by this fungal metabolite.