title: Combination of novel proteasome inhibitor NPI-0052 and lenalidomide trigger in vitro and in vivo synergistic cytotoxicity in multiple myeloma.
abstract: Our recent study demonstrated that a novel proteasome inhibitor NPI-0052 is distinct from bortezomib (Velcade) and, importantly, triggers apoptosis in multiple myeloma (MM) cells resistant to bortezomib. Here we demonstrate that combining NPI-0052 and lenalidomide (Revlimid) induces synergistic anti-MM activity in vitro using MM-cell lines or patient MM cells. NPI-0052 plus lenalidomide-induced apoptosis is associated with (1) activation of caspase-8, caspase-9, caspase-12, caspase-3, and poly(ADP) ribose polymerase; (2) activation of BH-3 protein BIM; (3) translocation of BIM to endoplasmic reticulum; (4) inhibition of migration of MM cells and angiogenesis; and (5) suppression of chymotrypsin-like, caspase-like, and trypsin-like proteasome activities. Importantly, blockade of BIM using siRNA significantly abrogates NPI-0052 plus lenalidomide-induced apoptosis. Furthermore, studies using biochemical inhibitors of caspase-8 versus caspase-9 demonstrate that NPI-0052 plus lenalidomide-triggered apoptosis is primarily dependent on caspase-8 signaling. In animal tumor model studies, low-dose combination of NPI-0052 and lenalidomide is well tolerated, significantly inhibits tumor growth, and prolongs survival. Taken together, our study provides the preclinical rationale for clinical protocols evaluating lenalidomide together with NPI-0052 to improve patient outcome in MM.
authors: LeBow Institute for Myeloma Therapeutics and Jerome Lipper Myeloma Center, Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA. Dharminder_Chauhan@dfci.harvard.edu
authors: Dharminder
authors: D
authors: Chauhan
authors: Ajita V
authors: AV
authors: Singh
authors: Bryan
authors: B
authors: Ciccarelli
authors: Paul G
authors: PG
authors: Richardson
authors: Michael A
authors: MA
authors: Palladino
authors: Kenneth C
authors: KC
authors: Anderson
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D006801:Humans; D066298:In Vitro Techniques; D007783:Lactones / Q000494:pharmacology*; D000077269:Lenalidomide; D051379:Mice; D016513:Mice, SCID; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000473:pathology*; D061988:Proteasome Inhibitors; D011758:Pyrroles / Q000494:pharmacology*; D013792:Thalidomide / Q000031:analogs & derivatives* / Q000494:pharmacology; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D007783:Lactones; D061988:Proteasome Inhibitors; D011758:Pyrroles; D013792:Thalidomide; C475865:marizomib; D000077269:Lenalidomide