title: The small-molecule VEGF receptor inhibitor pazopanib (GW786034B) targets both tumor and endothelial cells in multiple myeloma.
abstract: A critical role for vascular endothelial factor (VEGF) has been demonstrated in multiple myeloma (MM) pathogenesis. Here, we characterized the effect of the small-molecule VEGF receptor inhibitor pazopanib on MM cells in the bone marrow milieu. Pazopanib inhibits VEGF-triggered signaling pathways in both tumor and endothelial cells, thereby blocking in vitro MM cell growth, survival, and migration, and inhibits VEGF-induced up-regulation of adhesion molecules on both endothelial and tumor cells, thereby abrogating endothelial cell-MM cell binding and associated cell proliferation. We show that pazopanib is the first-in-class VEGF receptor inhibitor to inhibit in vivo tumor cell growth associated with increased MM cell apoptosis, decreased angiogenesis, and prolonged survival in a mouse xenograft model of human MM. Low-dose pazopanib demonstrates synergistic cytotoxicity with conventional (melphalan) and novel (bortezomib and immunomodulatory drugs) therapies. Finally, gene expression and signaling network analysis show transcriptional changes of several cancer-related genes, in particular c-Myc. Using siRNA, we confirm the role of c-Myc in VEGF production and secretion, as well as angiogenesis. These preclinical studies provide the rationale for clinical evaluation of pazopanib, alone and in combination with conventional and novel therapies, to increase efficacy, overcome drug resistance, reduce toxicity, and improve patient outcome in MM.
authors.affiliation: Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA. klaus.podar@dfci.harvard.edu
authors.forename: Klaus
authors.initials: K
authors.lastname: Podar
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tonon
authors.forename: Martin
authors.initials: M
authors.lastname: Sattler
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Tai
authors.forename: Steven
authors.initials: S
authors.lastname: Legouill
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yasui
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishitsuka
authors.forename: Shaji
authors.initials: S
authors.lastname: Kumar
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kumar
authors.forename: Lini N
authors.initials: LN
authors.lastname: Pandite
authors.forename: Teru
authors.initials: T
authors.lastname: Hideshima
authors.forename: Dharminder
authors.initials: D
authors.lastname: Chauhan
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Anderson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D042783:Endothelial Cells / Q000187:drug effects*; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007191:Indazoles; D051379:Mice; D046228:Microarray Analysis; D009101:Multiple Myeloma / Q000188:drug therapy / Q000378:metabolism*; D009389:Neovascularization, Pathologic / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D011743:Pyrimidines / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use; D034741:RNA, Small Interfering / Q000235:genetics; D040262:Receptors, Vascular Endothelial Growth Factor / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D013449:Sulfonamides / Q000378:metabolism* / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D007191:Indazoles; C489427:MYC protein, human; D016271:Proto-Oncogene Proteins c-myc; D011743:Pyrimidines; D034741:RNA, Small Interfering; D013449:Sulfonamides; C516667:pazopanib; D040262:Receptors, Vascular Endothelial Growth Factor