title: SDX-101, the R-enantiomer of etodolac, induces cytotoxicity, overcomes drug resistance, and enhances the activity of dexamethasone in multiple myeloma.
abstract: In this study we report that R-etodolac (SDX-101), at clinically relevant concentrations, induces potent cytotoxicity in drug-sensitive multiple myeloma (MM) cell lines, as well as in dexamethasone (MM.1R)-, doxorubicin (Dox40/RPMI8226)-, and bortezomib (DHL4)-resistant cell lines. Immunoblot analysis demonstrates that R-etodolac induces apoptosis characterized by caspase-8, -9, and -3 and PARP (poly-ADP [adenosine diphosphate]-ribose polymerase) cleavage and down-regulation of cyclin D1 expression. Subcytotoxic doses of R-etodolac up-regulate myeloid cell leukemia-1 proapoptotic variant (Mcl-1S), while enhancing dexamethasone (Dex)-induced caspase activation and apoptosis. The combination of R-etodolac with Dex results in a highly synergistic cytotoxic effect. R-etodolac also induces apoptosis against primary cells isolated from patients with MM refractory to chemotherapy. Although interleukin 6 (IL-6) and insulin-like growth factor-1 (IGF-1) abrogate Dex-induced MM cell cytotoxicity, neither IL-6 nor IGF-1 protects against R-etodolac-induced cytotoxicity in MM cells. R-etodolac also inhibits viability of MM cells adherent to bone marrow stromal cells (BMSCs), thereby overcoming a mechanism of drug resistance commonly observed with other conventional chemotherapeutic agents. Our data, therefore, indicate that R-etodolac circumvents drug resistance in MM cells at clinically relevant concentrations, targets Mcl-1, and can be synergistically combined with Dex.
authors.affiliation: Jerome Lipper Multiple Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Mayer 557, 44 Binney St, Boston, MA 02115, USA.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yasui
authors.forename: Teru
authors.initials: T
authors.lastname: Hideshima
authors.forename: Makoto
authors.initials: M
authors.lastname: Hamasaki
authors.forename: Aldo M
authors.initials: AM
authors.lastname: Roccaro
authors.forename: Norihiko
authors.initials: N
authors.lastname: Shiraishi
authors.forename: Shaji
authors.initials: S
authors.lastname: Kumar
authors.forename: Pierfrancesco
authors.initials: P
authors.lastname: Tassone
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishitsuka
authors.forename: Noopur
authors.initials: N
authors.lastname: Raje
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Tai
authors.forename: Klaus
authors.initials: K
authors.lastname: Podar
authors.forename: Dharminder
authors.initials: D
authors.lastname: Chauhan
authors.forename: Lorenzo M
authors.initials: LM
authors.lastname: Leoni
authors.forename: Sarath
authors.initials: S
authors.lastname: Kanekal
authors.forename: Gary
authors.initials: G
authors.lastname: Elliott
authors.forename: Nikhil C
authors.initials: NC
authors.lastname: Munshi
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Anderson
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001854:Bone Marrow Cells / Q000187:drug effects / Q000473:pathology; D020169:Caspases / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D019938:Cyclin D1 / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage*; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D017308:Etodolac / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D000970:Antineoplastic Agents; D015850:Interleukin-6; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D009363:Neoplasm Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D019938:Cyclin D1; D017308:Etodolac; D007334:Insulin-Like Growth Factor I; D003907:Dexamethasone; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases