title: Dynamic contrast-enhanced magnetic resonance imaging of vascular changes induced by sunitinib in papillary renal cell carcinoma xenograft tumors.
abstract: To investigate further the antiangiogenic potential of sunitinib for renal cell carcinoma (RCC) treatment, its effects on tumor vasculature were monitored by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using an orthotopic KCI-18 model of human RCC xenografts in nude mice. Tumor-bearing mice were treated with various doses of sunitinib, and vascular changes were assessed by DCE-MRI and histologic studies. Sunitinib induced dose-dependent vascular changes, which were observed both in kidney tumors and in normal kidneys by DCE-MRI. A dosage of 10 mg/kg per day caused mild changes in Gd uptake and clearance kinetics in kidney tumors. A dosage of 40 mg/kg per day induced increased vascular tumor permeability with Gd retention, probably resulting from the destruction of tumor vasculature, and also caused vascular alterations of normal vessels. However, sunitinib at 20 mg/kg per day caused increased tumor perfusion and decreased vascular permeability associated with thinning and regularization of tumor vessels while mildly affecting normal vessels as confirmed by histologic diagnosis. Alterations in tumor vasculature resulted in a significant inhibition of KCI-18 RCC tumor growth at sunitinib dosages of 20 and 40 mg/kg per day. Sunitinib also exerted a direct cytotoxic effect in KCI-18 cells in vitro. KCI-18 cells and tumors expressed vascular endothelial growth factor receptor 2 and platelet-derived growth factor receptor beta molecular targets of sunitinib that were modulated by the drug treatment. These data suggest that a sunitinib dosage of 20 mg/kg per day, which inhibits RCC tumor growth and regularizes tumor vessels with milder effects on normal vessels, could be used to improve blood flow for combination with chemotherapy. These studies emphasize the clinical potential of DCE-MRI in selecting the dose and schedule of antiangiogenic compounds.
authors.affiliation: Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA. hillmang@karmanos.org
authors.forename: Gilda G
authors.initials: GG
authors.lastname: Hillman
authors.forename: Vinita
authors.initials: V
authors.lastname: Singh-Gupta
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Areen K
authors.initials: AK
authors.lastname: Al-Bashir
authors.forename: Yashwanth
authors.initials: Y
authors.lastname: Katkuri
authors.forename: Meng
authors.initials: M
authors.lastname: Li
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Yunker
authors.forename: Amit D
authors.initials: AD
authors.lastname: Patel
authors.forename: Judith
authors.initials: J
authors.lastname: Abrams
authors.forename: E Mark
authors.initials: EM
authors.lastname: Haacke
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects*; D002292:Carcinoma, Renal Cell / Q000098:blood supply* / Q000188:drug therapy* / Q000556:secondary; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D000860:Hypoxia; D047468:Immunoprecipitation; D007211:Indoles / Q000494:pharmacology*; D007680:Kidney Neoplasms / Q000098:blood supply / Q000188:drug therapy / Q000473:pathology; D008279:Magnetic Resonance Imaging; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000517:prevention & control*; D011758:Pyrroles / Q000494:pharmacology*; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism; D000077210:Sunitinib; D014407:Tumor Cells, Cultured; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
chemical_list: D000970:Antineoplastic Agents; D003287:Contrast Media; D007211:Indoles; D011758:Pyrroles; D017479:Receptors, Platelet-Derived Growth Factor; D040301:Vascular Endothelial Growth Factor Receptor-2; D019786:Gadolinium DTPA; D000077210:Sunitinib