Early gene signalling-dependent and -independent induction of apoptosis in Ramos human B cells can be inhibited by over-expression of Bcl-2.

Abstract

We have previously shown that calcium ionophore-induced apoptosis of Ramos human B cells is preceded by the induced expression of early response genes, implying a requirement for new gene expression in this mode of programmed cell death. We have found in the present studies that inhibitors of macromolecular synthesis, cycloheximide and actinomycin D, are also potent inducers of apoptosis in the same Ramos cell model. These drugs trigger apoptosis through apparently early gene signalling-independent pathways. Although different mechanisms for induction of apoptosis exist in Ramos cells, enforced over-expression of Bcl-2 protects cells from apoptosis induced in response to different agents, demonstrating that Bcl-2 blocks a final common pathway for programmed cell death in the Ramos cell model.