Light and Bryostatin, a Protein Kinase C Activator, Promote Proliferation of Human Epidermal Keratinocyte Cultures

Abstract

Bryostatin is supposed to be a natural protein kinase C(PK-C) activator lacking tumor promoting activity. It induces differentiation of many transformed cell lines. In normal cells, bryostatin was shown to induce markers of proliferation but not of differentiation (e.g. in primary mouse keratinocytes). Recently, we have found that bryostatin promotes proliferation of human epidermal keratinocytes (HEK) most effectively at 75 ng/ml, in at least two modes of action: (a) it increased 4- to 7-fold the plating efficiency of primary cultures, presumably by increasing the fraction of proliferative basal cells; and (b) it increased the yield of cells of secondary cultures, presumably by effecting the length of the cell cycle.