Oncogenic transformation increases the sensitivity for apoptosis induction by inhibitors of macromolecular synthesis

Abstract

Inhibition of RNA or protein synthesis causes apoptosis in fibroblasts. This points to the constitutive expression of a long-lived apoptosis machinery which is controlled by shortlived negative regulatory proteins, termed endogenous survival factors. The length of time between addition of the inhibitor of macromolecular synthesis and the onset of apoptosis can be used as an estimation of the effective survival factor concentration. Transformation of rat fibroblasts by a constitutively expressed src oncogene or an inducible ras oncogene increases the sensitivity for apoptosis induction by inhibitors of macromolecular synthesis, indicating that their endogenous survival factor pool has been decreased.