EFFECTS OF ACTIVATORS AND INHIBITORS OF PROTEIN-KINASE-C ON X-RAY-INDUCED MALIGNANT TRANSFORMATION INVITRO

We have examined the effects on X-ray induced malignant transformation in vitro of a number of activators and inhibitors of protein kinase C (PKC). Several of these substances were found to enhance or inhibit transformation, and the extent of the effects on transformation were found to be consistent with the potencies of the substances in activating or inhibiting PKC. Additionally, the observed transformation enhancement was found to be reversed by the presence of the anticarcinogenic protease inhibitors antipain or the Bowman-Birk inhibitor. These results suggest that activation of protein kinase C may be involved in the mechanism of in vitro X-ray induced malignant transformation.