title: Mechanism underlying cytotoxicity of thialysine, lysine analog, toward human acute leukemia Jurkat T cells.
abstract: We first report the mechanism for the inhibitory effect of the lysine analog, thialysine on human acute leukemia Jurkat T cells. When Jurkat T cells were treated with thialysine (0.32-2.5 mM), apoptotic cell death along with several biochemical events such as mitochondrial cytochrome c release, caspase-9 activation, caspase-3 activation, degradation of poly (ADP-ribose) polymerase, and DNA fragmentation was induced in a dose- and time-dependent manner. However, these thialysine-induced apoptotic events were significantly abrogated by an ectopic expression of Bcl-xL, which is known to block mitochondrial cytochrome c release. Decylubiquinone, a mitochondrial permeability transition pore inhibitor, also suppressed thialysine-induced apoptotic events. Comparison of the thialysine-induced alterations in the cell cycle distribution between Jurkat T cells transfected with Bcl-xL gene (J/Bcl-xL) and Jurkat T cells transfected with vector (J/Neo) revealed that the apoptotic cells were mainly derived from the cells accumulated in S and G2/M phases following thialysine treatment. The interruption of cell cycle progression in the presence of thialysine was accompanied by a significant decline in the protein level of cdk4, cdk6, cdc2, cyclin A, cyclin B1, and cyclin E. These results demonstrate that the cytotoxic activity of thialysine toward Jurkat T cells is attributable to not only apoptotic cell death mediated by a mitochondria-dependent death signaling pathway, but also interruption of cell cycle progression by a massive down-regulation in the level of cdks and cyclins.
authors.affiliation: Laboratory of Immunobiology, Department of Microbiology, College of Natural Sciences, Kyungpook National University, 702-701 Taegu, South Korea.
authors.forename: Do Youn
authors.initials: DY
authors.lastname: Jun
authors.forename: Seok Woo
authors.initials: SW
authors.lastname: Rue
authors.forename: Kyu Hyun
authors.initials: KH
authors.lastname: Han
authors.forename: Dennis
authors.initials: D
authors.lastname: Taub
authors.forename: Young Sup
authors.initials: YS
authors.lastname: Lee
authors.forename: Young Seuk
authors.initials: YS
authors.lastname: Bae
authors.forename: Young Ho
authors.initials: YH
authors.lastname: Kim
mesh_terms: D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D003545:Cysteine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D019169:Jurkat Cells; D007938:Leukemia; D008239:Lysine / Q000737:chemistry*; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein
chemical_list: C494811:BCL2L1 protein, human; D011500:Protein Synthesis Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; C000204:S-2-aminoethyl cysteine; D045304:Cytochromes c; D020169:Caspases; D008239:Lysine; D003545:Cysteine