Cell culture medium 199 (M199) was from Lonza (Verviers, Belgium). Recombinant human VEGF-165 was purchased from R&D Systems, Inc. (Minneapolis, MN, USA). Human plasma fibrinogen was acquired from Merck/Millipore (Darmstadt, Germany). Proteinase inhibitor mixture complete, EDTA-free, was purchased from Roche Diagnostics (Mannheim, Germany). Imatinib, nilotinib and ponatinib were from Cayman Chemical (Ann Arbor, MI, USA). All other reagents were from Sigma-Aldrich (Taufkirchen, Germany) unless otherwise stated.