title: Alpha-tocopheryl succinate sensitizes human colon cancer cells to exisulind-induced apoptosis.
abstract: Sulindac sulfone (also known as exisulind) and its chemical derivatives are promising anticancer agents capable of inducing apoptosis in a variety of malignant cell types with minimal toxicity to normal cells. Here, we tested the ability of alpha-tocopheryl succinate (TOS), another promising anticancer agent, to sensitize colon cancer cells to exisulind-induced apoptosis. We found that sub-apoptotic doses of TOS greatly enhanced exisulind-induced growth suppression and apoptosis in the HCT116, LoVo and SNU-C4 human colon cancer cell lines. Our results revealed that this was accounted for primarily by an augmented cleavage of poly(ADP-ribose) polymerase (PARP) and enhanced activation of caspase-8, -9 and -3. Pretreatment with z-VAD-FMK (a pan-caspase inhibitor), z-IETD-FMK (a caspase-8 inhibitor) or z-LEHD-FMK (a caspase-9 inhibitor) blocked TOS and exisulind cotreatment-induced PARP cleavage and apoptosis. Furthermore, TOS/exisulind cotreatment induced JNK phosphorylation, while pretreatment with SP600151 (a JNK inhibitor) partially blocked cotreatment-induced caspase-dependent PARP cleavage and apoptosis. Taken together, these findings indicate that TOS sensitizes human colon cancer cells to exisulind-induced apoptosis. Apoptotic synergy induced by exisulind plus TOS seems likely to be mediated through a mechanism involving activation of caspases and JNK.
authors.affiliation: Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea. sjlim@sejong.ac.kr
authors.forename: Soo-Jeong
authors.initials: SJ
authors.lastname: Lim
authors.forename: Young-Ju
authors.initials: YJ
authors.lastname: Lee
authors.forename: Dae-Hun
authors.initials: DH
authors.lastname: Park
authors.forename: Eunmyong
authors.initials: E
authors.lastname: Lee
authors.forename: Moon-Kyung
authors.initials: MK
authors.lastname: Choi
authors.forename: Wanseo
authors.initials: W
authors.lastname: Park
authors.forename: Kyung-Hee
authors.initials: KH
authors.lastname: Chun
authors.forename: Han-Gon
authors.initials: HG
authors.lastname: Choi
authors.forename: Jung Sik
authors.initials: JS
authors.lastname: Cho
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D061945:Caspase Inhibitors; D048708:Cell Growth Processes / Q000187:drug effects; D003110:Colonic Neoplasms / Q000473:pathology*; D004357:Drug Synergism; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D045325:HCT116 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D013467:Sulindac / Q000031:analogs & derivatives* / Q000494:pharmacology; D024505:Tocopherols; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D014810:Vitamin E; D013467:Sulindac; D048031:JNK Mitogen-Activated Protein Kinases; C025463:sulindac sulfone; D024505:Tocopherols