DIPROPYLCYCLOPENTYLXANTHINE TRIGGERS APOPTOSIS IN JURKAT T-CELLS BY ARECEPTOR-INDEPENDENT MECHANISM

1,3-Dipropyl-8-cyclopentylxanthine (DPCPX), a xanthine analog used as selective antagonist of adenosine receptors, caused apoptosis in a hum an leukemia T cell line. Jurkat cells treated with DPCPX underwent apo ptosis as demonstrated by flow cytometry, by DNA fragmentation and by accumulation of histones, H2A, H2B, H3 and H4, in the nucleoplasm of c ells, Cell cycle and cell sorting analyses indicated an arrest of cell s in G(2)/M followed by the appearance of apoptotic cells in G(1) and G(2)/M phases. The mechanism of programmed cell death does not seem to be mediated by signal transduction events at the plasma membrane sinc e it did not involve activation of cell membrane receptors and modific ation of the intracellular levels of Ca2+ or cAMP. Apoptosis by incorp oration into DNA of a derivative of DPCPX is suggested in basis of the presence of radioactivity label in the DNA obtained from cells preinc ubated with [H-3]DPCPX.