title: Inhibiting the IGF-1 receptor tyrosine kinase with the cyclolignan PPP: an in vitro and in vivo study in the 5T33MM mouse model.
abstract: Insulin-like growth factor 1 (IGF-1) plays a pleiotropic role in multiple myeloma (MM), that is, in survival, proliferation, chemotaxis, and angiogenesis. Strategies targeting the IGF-1 receptor (IGF-1R) may therefore be important to develop efficient anti-MM agents. In this work we investigated the effect of an IGF-1R tyrosine kinase (IGF-1RTK) inhibitor (picropodophyllin or PPP) in the 5T33MM mouse model. In vitro data showed that PPP reduced IGF-1R autophosphorylation and downstream ERK activation, leading to inhibition of IGF-1-stimulated proliferation and vascular endothelial growth factor (VEGF) secretion of MM cells. In an in vivo study, PPP reduced the bone marrow tumor burden and serum paraprotein in 5T33MM mice by 77% and 90%, respectively, compared to vehicle-treated animals. Angiogenesis was assessed by quantifying the microvessel density on CD31-stained paraffin sections and this was reduced by 60% in the PPP-treated group. In a separate survival experiment, Kaplan-Meier analysis demonstrated a significant increase in survival in PPP-treated 5T33MM animals compared to the vehicle controls (28 versus 18 days). These data suggest that the IGF-1RTK inhibitor PPP possesses a marked antitumor activity and strongly points to the possibility of using IGF-1R inhibitors in the treatment of MM.
authors.affiliation: Department of Hematology and Immunology, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Eline
authors.initials: E
authors.lastname: Menu
authors.forename: Helena
authors.initials: H
authors.lastname: Jernberg-Wiklund
authors.forename: Thomas
authors.initials: T
authors.lastname: Stromberg
authors.forename: Hendrik
authors.initials: H
authors.lastname: De Raeve
authors.forename: Leonard
authors.initials: L
authors.lastname: Girnita
authors.forename: Olle
authors.initials: O
authors.lastname: Larsson
authors.forename: Magnus
authors.initials: M
authors.lastname: Axelson
authors.forename: Kewal
authors.initials: K
authors.lastname: Asosingh
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nilsson
authors.forename: Ben
authors.initials: B
authors.lastname: Van Camp
authors.forename: Karin
authors.initials: K
authors.lastname: Vanderkerken
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D004789:Enzyme Activation; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D008833:Microcirculation; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009101:Multiple Myeloma / Q000098:blood supply / Q000188:drug therapy* / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000378:metabolism; D010266:Paraproteins / Q000378:metabolism; D010766:Phosphorylation; D011034:Podophyllotoxin / Q000031:analogs & derivatives* / Q000494:pharmacology; D017526:Receptor, IGF Type 1 / Q000037:antagonists & inhibitors* / Q000378:metabolism; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D042461:Vascular Endothelial Growth Factor A
chemical_list: D010266:Paraproteins; D042461:Vascular Endothelial Growth Factor A; C415032:picropodophyllin; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D019950:Mitogen-Activated Protein Kinase 1; D011034:Podophyllotoxin