title: Caspase-8 dependent osteosarcoma cell apoptosis induced by proteasome inhibitor MG132.
abstract: Many researchers have reported that proteasome inhibitors could induce apoptosis in a variety of cancer cells, such as breast cancer cell, lung cancer cell, and lymphoma cell. However, the effect of proteasome inhibitors on osteocsarcoma cells and the mechanisms are seldom studied. In this study, we found proteasome inhibitor MG132 was an effective inducer of apoptosis in human osteosarcoma MG-63 cells. On normal human diploid fibroblast cells, MG132 did not show any apoptosis-inducing effects. Apoptotic changes such as DNA fragment and apoptotic body were observed in MG132-treated cells and MG132 mostly caused MG-63 cell arrest at G(2)-M-phase by cell cycle analysis. Increased activation of caspase-8, accumulation of p27(Kip1), and an increased ratio of Bax:Bcl-2 were detected by RT-PCR and Western blot analysis. Activation of caspase-3 and caspase-9 were not observed. This suggests that the apoptosis induced by MG132 in MG63 cells is caspase-8 dependent, p27 and bcl-2 family related.
authors.affiliation: Department of Orthopaedics, 2nd Affiliated Hospital, School of Medicine, Zhejiang University, 88 Jie Fang Road, Hangzhou 310009, Zhejiang, PR China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Yan
authors.forename: Di-Sheng
authors.initials: DS
authors.lastname: Yang
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.forename: Jie
authors.initials: J
authors.lastname: Feng
authors.forename: Zhong-Li
authors.initials: ZL
authors.lastname: Shi
authors.forename: Zhaoming
authors.initials: Z
authors.lastname: Ye
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D001859:Bone Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D053181:Caspase 8 / Q000378:metabolism*; D002478:Cells, Cultured; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology*; D012516:Osteosarcoma / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051028:bcl-2-Associated X Protein / Q000378:metabolism; D051020:bcl-X Protein / Q000378:metabolism
chemical_list: D015853:Cysteine Proteinase Inhibitors; D007976:Leupeptins; D012333:RNA, Messenger; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D050760:Cyclin-Dependent Kinase Inhibitor p27; D053181:Caspase 8; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde