title: Antibody targeting of the insulin-like growth factor I receptor enhances the anti-tumor response of multiple myeloma to chemotherapy through inhibition of tumor proliferation and angiogenesis.
abstract: Although many multiple myeloma (MM) patients initially respond to cytotoxic therapy, most eventually relapse. Novel therapeutic strategies employing a combination of chemotherapy with targeted biologics may significantly enhance the response of tumor cells to treatment. We tested a fully human anti-IGF-IR antibody (A12) against MM, and showed specific inhibition of IGF-I or serum-induced IGF-IR signaling in MM cells in vitro. The A12 as a single agent was demonstrated to exert modest to significant inhibition of tumor growth in vivo in various subcutaneous xenograft MM models. The A12 was also evaluated in a disseminated xenograft MM.1S NOD/SCID model as monotherapy or in combination with other drugs (bortezomib, melphalan) currently in clinical use. The tumor burden, as determined by luciferase bioimaging, was sharply decreased, and overall survival significantly prolonged when the therapies were combined. Immunohistochemical analysis demonstrated that the A12 treated tumors had significantly decreased vascularization compared to control tumors. Furthermore, most MM lines constitutively secreted significant quantities of VEGF, and this was enhanced following IGF-I treatment. Inhibition of IGF-IR by the A12 in vitro suppressed both constitutive and IGF-I-induced secretion of VEGF, indicating that a putative anti-angiogenic mechanism associated with the A12 treatment may contribute to its anti-tumor effect.
authors.affiliation: James Ewing Laboratory of Developmental Hematopoiesis, Cell Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
authors.forename: Kai-Da
authors.initials: KD
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Zhou
authors.forename: Douglas
authors.initials: D
authors.lastname: Burtrum
authors.forename: Dale L
authors.initials: DL
authors.lastname: Ludwig
authors.forename: Malcolm A S
authors.initials: MA
authors.lastname: Moore
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000276:immunology / Q000494:pharmacology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001897:Boronic Acids / Q000008:administration & dosage; D000069286:Bortezomib; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009101:Multiple Myeloma / Q000188:drug therapy* / Q000276:immunology / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy*; D011719:Pyrazines / Q000008:administration & dosage; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000276:immunology; D013329:Structure-Activity Relationship; D015996:Survival Rate; D023041:Xenograft Model Antitumor Assays
chemical_list: D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D001897:Boronic Acids; D011719:Pyrazines; D000069286:Bortezomib; D017526:Receptor, IGF Type 1