The release of microparticles by Jurkat leukemia T cells treated with staurosporine and related kinase inhibitors to induce apoptosis.
Microparticles (MPs) are small membrane-bound vesicles released from cells undergoing activation or cell death. These particles display potent biological activities that can impact on physiologic and pathologic processes. Previous studies with the Jurkat T leukemia cell line demonstrated that staurosporine (STS) induces the release of MPs as cells undergo apoptosis. To investigate further this process, we tested the effects of STS, its analogue, 7-hydroxystaurosporine (UCN-01), and other protein kinase C (PKC) and cyclin-dependent kinase (CDK) inhibitors. FACS analysis was used to assess MP release. Results of these studies indicate that STS and UCN-01 induce MP release by Jurkat cells; in contrast, other PKC and CDK inhibitors failed to induce comparable release, suggesting that release does not result from simple inhibition of either kinase alone. Time course experiments indicated that STS-induced particle release occurred as early as 2 h after treatment, with the early release MPs displaying low levels of binding of annexin V and propidium iodide (PI). Early-release MPs, however, matured in culture to an annexin V- and PI-positive phenotype. Together, these results indicate that STS and UCN-01 induce MPs that are phenotypically distinct and reflect specific patterns of kinase inhibition during apoptosis.
Department of Medicine, Duke University, Durham, NC, USA. anirudh.ullal@duke.edu
Anirudh J
AJ
Ullal
David S
DS
Pisetsky
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D055252:Cell-Derived Microparticles / Q000737:chemistry / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005434:Flow Cytometry; D006801:Humans; D019169:Jurkat Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009696:Nucleic Acids / Q000032:analysis; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D009696:Nucleic Acids; D011493:Protein Kinase C; D019311:Staurosporine