Targeting malignant glioma cells in vitro using platelet-derived growth factor AA-based conjugates.

Glioblastoma multiforme (GBM) is an unusually aggressive brain tumor; it is also highly heterogeneous. Poor prognosis and a median survival of less than 1 year, using conventional treatment, calls for development of new treatment strategies. Overexpression and/or amplification of platelet-derived growth factor alpha receptors (PDGF alpha Rs) in GBM might act as potential targets for a novel therapeutic approach. In this study, conjugates based on PDGFAA-ligand and dextran, of different sizes (10 and 40 kDa dextran), were prepared and investigated regarding targeting properties in vitro. Three human malignant glioma cell lines, U343MGa31L, U343MGaCl2:6, and U563MG, were used because of their previously reported differences in receptor expression and behavior. PDGFAA-based 10 kDa dextran iodine-125 radiolabeled conjugates showed the most favorable properties according to results achieved in accumulation, retention, and localization of cell-associated radioactivity. In comparison with dextran-(125)I-tyrosine delivered radioactivity, the PDGFAA-based dextran conjugates confirm the potential of receptor targeting.