Medulloblastoma (MB) is the most common childhood brain tumor arising from the cerebellum. PI3K and BRD4 signaling pathways are known to induce MB cell growth, cancer stem cell (CSC) proliferation, and tumor resistance. Further, the tumor suppressor gene TP53 is found to be inactivated in MB due to overexpression of its negative regulator MDM2. In this study, we synthesized MDP5, a potent BRD4/PI3K dual inhibitor, and JW475A, a potent dual MDM2 and XIAP inhibitor. The combination of these two drugs significantly decreased the colony formation capacity compared to individual drugs. Given the challenge of inefficient drug transport across the blood-brain barrier (BBB), we prepared rabies virus glycoprotein (RVG) peptide decorated lipid nanoparticles (LNPs), which showed 4.9 ± 0.1 and 4.8 ± 0.1 % loading for MDP5 and JW475A, respectively. In vivo studies in mice showed that Cy5.5 labeled RVG-LNPs were detected in the brain after systemic administration. Combination drug-loaded RVG-LNPs significantly decreased the MB growth in orthotopic mouse model of MB compared to free drug combination and non-targeted LNPs. This study indicates that MDP5 and JW475A -loaded RVG-LNPs are a promising drug brain delivery system worth exploring further in clinical settings for MB therapy.
