We prepared and evaluated
transferrin (Tf) and
monoclonal antibody (mAb) 2C5-modified dual
ligand-targeted poly(
ethylene glycol)-
phosphatidylethanolamine micelles loaded with a poorly soluble drug, R547 (a selective
adenosine triphosphate-competitive
cyclin-dependent kinase inhibitor) for enhancement of targeting efficiency and cytotoxicity in vitro and in vivo to A2780 ovarian
carcinoma compared to single
ligand-targeted
micelles. Micellar solubilization significantly improved the solubility of R547 from 1 to 800 μg/mL. The size of modified and non-modified
micelles was 13-16 nm. Flow cytometry indicated significantly enhanced cellular association of dual
ligand-targeted
micelles compared to single
ligand-targeted
micelles. Confocal microscopy confirmed the Tf receptor-mediated endocytosis of
rhodamine-labeled Tf-modified
micelles after staining the
micelle-treated cells with the endosomal marker Tf-Alexa488. The optimized dual-targeted
micelles enhanced cytotoxicity in vitro against A2780
ovarian cancer cells compared to plain and single
ligand-targeted
micelles. Interestingly, in vivo anti-
tumor efficacy was more pronounced for the preparation with a single-targeting
ligand (Tf). The specific combination Tf and mAb 2C5 did not yield the expected increase in efficacy as was observed in vitro. This observation suggests that the relationships between targeting
ligands in vivo could be more complex than in simplified in vitro systems, and the results of the optimization process should always be verified in vivo.