MDM2 antagonist-loaded targeted micelles in combination with doxorubicin: effective synergism against human glioblastoma via p53 re-activation.

p53, The tumour suppressor protein encoded by P53 gene, is the most commonly altered protein in the human malignancies. MDM2 controls the p53 activity through an autoregulatory feedback loop. p53 activates the expression of MDM2 and in return, MDM2 blocks the p53 activity through various mechanisms. Nutlins, including nutlin-3, are a new class of small molecules that bind to MDM2 and prevent its interaction with p53. This antagonism results in increased p53 activity and can also re-activates the p53 pathway and resensitize the glioblastoma cells to apoptosis. Here we used nutlin-3 in combination with another potent anticancer drug, doxorubicin, to investigate the synergism between these drugs. We encapsulated both water-insoluble drugs in the PEG-PE-based micellar nanocarriers efficiently and evaluate their efficacy against U87MG cells in 2 D and 3 D models. These nanomedicine formulations successfully re-activated the p53 levels in cells, increased the apoptosis and showed strong synergistic cytotoxic effect.