Development and Nanoparticle-Mediated Delivery of Novel MDM2/MDM4 Heterodimer Peptide Inhibitors to Enhance 5-Fluorouracil Nucleolar Stress in Colorectal Cancer Cells
Francesco Merlino, Annalisa Pecoraro, Giuseppe Longobardi, Greta Donati, Francesco Saverio Di Leva, Chiara Brignola, Rebecca Piccarducci, Simona Daniele, Claudia Martini, Luciana Marinelli, Giulia Russo, Fabiana Quaglia, Claudia Conte, Annapina Russo, Valeria La Pietra
Abstract
Colorectal cancer (CRC) often involves wild-type p53 inactivation by MDM2 and MDM4 overexpression, promoting tumor progression and resistance to 5-fluoruracil (5-FU). Disrupting the MDM2/4 heterodimer can proficiently reactivate p53, sensitizing cancer cells to 5-FU. Herein, we developed 16 peptides based on Pep3 ( 1 ), the only known peptide acting through this mechanism. The new peptides, notably 3 and 9, showed lower IC 50 values than 1 . When incorporated into tumor-targeted biodegradable nanoparticles, these exhibited cytotoxicity against three different CRC cell lines. Notably, NPs/ 9 caused a significant increase in p53 levels associated with a strong increment of its main downstream target p21 inducing apoptosis. Also, the combined treatment of 9 with 5-FU caused the activation of nucleolar stress and a synergic apoptotic effect. Hence, the co-delivery of MDM2/4 heterodimer disruptors with 5-FU through nanoparticles might be a promising strategy to overcome drug resistance in CRC.