STUDIES ON THE RELATIONSHIP BETWEEN CELL-PROLIFERATION AND CELL-DEATH - OPPOSITE PATTERNS OF SGP-2 AND ORNITHINE DECARBOXYLASE MESSENGER-RNA ACCUMULATION IN PHA-STIMULATED HUMAN-LYMPHOCYTES

To assess the relationship between cell proliferation and cell death, the mRNA accumulation of ornithine decarboxylase (ODC) and sulfated glycoprotein 2 (SGP-2) were measured in human peripheral blood lymphocytes (HPBL) 2-6 hours after stimulation with phytohemoagglutinin (PHA). ODC is the rate limiting enzyme of polyamines biosynthesis and its early induction in mitogen-stimulated lymphocytes has been reported. On the other hand, SGP-2, a glycoprotein present in most mammalian tissues, is induced in classical models of apoptosis, such as dexamethasone-treated thymocytes. Indeed, a consistent amount of SGP-2 mRNA in quiescent HPBL, an early and progressive decrease of SGP-2 mRNA and a parallel increase of ODC mRNA accumulation, were observed, in PHAstimulated HPBL, suggesting that concomitant repression of SGP-2 and induction of ODC genes contribute for the cell entering the cell cycle. © 1991 Academic Press, Inc.