Photosensitizer and Sunitinib Preparation

The photosensitizer (PS) TPCS_2a (PCI Biotech AS, Oslo, Norway) was dissolved at 0.4 mg/mL in 3% Tween 80, 2.8% mannitol, 50 mM Tris, pH 8.5 (all from Sigma-Aldrich), and kept protected from light at 4 °C. Sunitinib malate (PZ0012, Sigma-Aldrich) was for in vitro experiments dissolved in dimetylsulfoxid (DMSO) to a final concentration of 2.5 mM, stored as aliquots at −20 °C, and subjected to maximum two freeze-thaw cycles. Sunitinib malate for in vivo experiments was dissolved at a concentration of 8 mg/mL (20 mM) in a vehicle containing distilled water with 1.8% NaCl, 0.5% carboxymethylcellulose, 0.4% Tween 80 and 0.9% benzylalcohol. The pH of the solution was adjusted to 6.0. The sunitinib mixture was sonicated to achieve stable dispersion [45 (link)] and used within 24 h after sonication. All sunitinib reagents were stored protected from light. Recombinant gelonin (rGel) was generously provided by Dr. Michael Rosenblum’s laboratory at M.D. Anderson Cancer Center (Houston, TX, USA). Aliquots of rGel were stored in phosphate-buffered saline (PBS) at −20 °C. All experiments in vitro and in vivo with sunitinib and/or TPCS_2a were performed under subdued light.