title: Combined anti-PDGFRalpha and PDGFRbeta targeting in non-small cell lung cancer.
abstract: Activation of the platelet-derived growth factor (PDGF)-receptors is critically involved into various stromal cell functions including recruitment of stromal cells and vascular endothelial growth factor (VEGF) induction in tumor and perivascular cells. To evaluate the effects of combined PDGFRalpha and -beta inhibition in a non-small cell lung cancer model, we stably transfected A549 lung cancer cells with the PDGF-A mutant PDGF-0. PDGF-0 has been generated by substituting amino acids in the binding region of PDGF-A with the corresponding VEGF-A region, leading to a decreased receptor-binding affinity and activation. Compared with control vector transfected cells, transfection with PDGF-0 had no impact on monolayer growth and apoptosis in vitro, but significantly impaired the number of colony formation in soft agar. After subcutaneous injections, all mice developed tumors within 5 days. While control vector transfected A549 cells were characterized by constant tumor growth, PDGF-0 transfected A549 revealed a reduced tumor mass (p < 0.001) with no further growth beyond 14 days (2 months observation time) and complete regressions in 7 of 13 cases. Immunohistochemical analyses revealed that PDGF-0 transfected tumors demonstrated decreased recruitment of periendothelial cells, while the tumor invasion zone was similar to control vector transfectants. Similarly, conditioned medium from PDGF-0 transfected cells induced significantly less migration of smooth muscle cells and fibroblasts in vitro. Interestingly, in PDGF-0 transfectants, neither total vessel count nor VEGF expression were significantly altered. These studies demonstrate that combined inhibition of PDGFRalpha and -beta results in markedly decreased tumor growth in vivo because of impaired recruitment of periendothelial cells.
authors.affiliation: Department of Medicine/Hematology and Oncology and the IZKF Muenster, University of Muenster, Muenster, Germany. niels.reinmuth@thoraxklinik-heidelberg.de
authors.forename: Niels
authors.initials: N
authors.lastname: Reinmuth
authors.forename: Ruediger
authors.initials: R
authors.lastname: Liersch
authors.forename: Miriam
authors.initials: M
authors.lastname: Raedel
authors.forename: Frauke
authors.initials: F
authors.lastname: Fehrmann
authors.forename: Nicole
authors.initials: N
authors.lastname: Fehrmann
authors.forename: Michael
authors.initials: M
authors.lastname: Bayer
authors.forename: Christian
authors.initials: C
authors.lastname: Schwoeppe
authors.forename: Torsten
authors.initials: T
authors.lastname: Kessler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Berdel
authors.forename: Michael
authors.initials: M
authors.lastname: Thomas
authors.forename: Rolf M
authors.initials: RM
authors.lastname: Mesters
mesh_terms: D000818:Animals; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002465:Cell Movement; D016503:Drug Delivery Systems; D005109:Extracellular Matrix / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism; D009154:Mutation; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010982:Platelet-Derived Growth Factor / Q000235:genetics; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism*; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D017154:Stromal Cells / Q000378:metabolism; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D010982:Platelet-Derived Growth Factor; D042461:Vascular Endothelial Growth Factor A; C075278:platelet-derived growth factor A; D020796:Receptor, Platelet-Derived Growth Factor alpha; D020797:Receptor, Platelet-Derived Growth Factor beta