title: Proteomic evaluation of pathways associated with dexamethasone-mediated apoptosis and resistance in multiple myeloma.
abstract: We have used global protein expression analysis to characterize the pathways of dexamethasone-mediated apoptosis and resistance in myeloma. Analysis of MM.1S cells by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) identified a series of proteins that were up- and downregulated following dexamethasone treatment. Downregulated proteins included proteins involved in cell survival and proliferation, whereas upregulated proteins were involved in post-translational modification, protein folding and trafficking. A comparison with published gene expression studies identified FK binding protein 5 (FKBP5) (also known as FKBP51), a key regulatory component of the Hsp90-steroid-receptor complex to be increased at the mRNA and protein level postdexamethasone exposure. Quantitative real time polymerase chain reaction and 2D-PAGE analysis of the dexamethasone resistant cell line MM.1R demonstrated no increase in FKBP5, consistent with its association with dexamethasone-mediated apoptosis. Western blot analysis of FKBP5 and other members of the Hsp90-receptor complex showed an increase in FKBP5 whilst FKBP4 (also known as FKBP52) and Hsp90 expression remained constant. No changes were observed in MM.1R. In conclusion, we demonstrated that following steroid receptor signalling, the cell carries out a number of adaptive responses prior to cell death. Interfering with these adaptive responses may enhance the myeloma killing effect of dexamethasone.
authors.affiliation: Academic Unit of Haematology and Oncology, School of Medicine, Algernon Firth Building, University of Leeds, Leeds, UK.
authors.forename: Karen S
authors.initials: KS
authors.lastname: Rees-Unwin
authors.forename: Rachel A
authors.initials: RA
authors.lastname: Craven
authors.forename: Emma
authors.initials: E
authors.lastname: Davenport
authors.forename: Sarah
authors.initials: S
authors.lastname: Hanrahan
authors.forename: Nicholas F
authors.initials: NF
authors.lastname: Totty
authors.forename: Ann M
authors.initials: AM
authors.lastname: Dring
authors.forename: Rosamonde E
authors.initials: RE
authors.lastname: Banks
authors.forename: Gareth
authors.initials: G
authors.lastname: J Morgan
authors.forename: Faith E
authors.initials: FE
authors.lastname: Davies
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D003907:Dexamethasone / Q000627:therapeutic use*; D015536:Down-Regulation; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D015180:Electrophoresis, Gel, Two-Dimensional; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D009101:Multiple Myeloma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000187:drug effects / Q000378:metabolism*; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism; D011987:Receptors, Steroid / Q000378:metabolism; D022021:Tacrolimus Binding Proteins / Q000378:metabolism / Q000502:physiology; D014407:Tumor Cells, Cultured; D015854:Up-Regulation; D000099159:Tacrolimus Binding Protein 5
chemical_list: D018931:Antineoplastic Agents, Hormonal; D003907:Dexamethasone; D018841:HSP90 Heat-Shock Proteins; D009363:Neoplasm Proteins; D012333:RNA, Messenger; D011987:Receptors, Steroid; D022021:Tacrolimus Binding Proteins; D000099159:Tacrolimus Binding Protein 5