title: Molecular mechanisms of apoptosis induced by 3'-ethynylcytidine.
abstract: 1-(3-C-Ethynyl-beta-D-ribo-pentofuranosyl)cytosine (3'-Ethynylcytidine; ECyd), a ribonucleoside analog, has a potent cytotoxic activity against cancer cells. We have investigated the cancer-cell death induced by ECyd, focusing on its molecular mechanisms. In ECyd-treated cells, RNase L is activated and involved in c-jun NH(2)-terminal kinase (JNK) phosphorylation, followed by induction of mitochondria-dependent apoptosis. The mechanism of JNK phophorylation by RNase L was unknown. To investigate the mechanism, we performed the identification of RNase L-binding partners by proteomic approach using co-immunoprecipitation and mass spectrometry. We found that RNase L was associated with a protein (we named it Protein-190). At the same time, we observed that Protein-190 was amply phosphorylated. Furthermore, the participation of Protein-190 in the ECyd-induced apoptosis was supported by a knockdown experiment using small interfering RNA (siRNA). Thus, the number of ECyd-induced apoptotic cells was drastically decreased when Protein-190 was knocked-down. These results indicated Protein-190 as a regulator in apoptosis, and provide the possibility for a new clinical target in cancer chemotherapy.
authors.affiliation: Faculty of Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan. wataya@cc.okayama-u.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Wataya
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Naito
authors.forename: Akira
authors.initials: A
authors.lastname: Sato
authors.forename: Akiko
authors.initials: A
authors.lastname: Hiramoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kitade
authors.forename: Takuma
authors.initials: T
authors.lastname: Sasaki
authors.forename: Akira
authors.initials: A
authors.lastname: Matsuda
authors.forename: Masakazu
authors.initials: M
authors.lastname: Fukushima
authors.forename: Hye-Sook
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis; D003562:Cytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004722:Endoribonucleases / Q000378:metabolism
chemical_list: C103084:1-(3-C-ethynylribopentofuranosyl)cytosine; D000970:Antineoplastic Agents; D003562:Cytidine; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease