No abstract

Efficient cytosolic protein delivery is necessary to fully realize the potential of protein therapeutics. Current methods of protein delivery often suffer from low serum tolerance and limited in vivo efficacy. Here, we report the synthesis and validation of a previously unreported class of carboxylated branched poly(β-amino ester)s that can self-assemble into nanoparticles for efficient intracellular delivery of a variety of different proteins. In vitro, nanoparticles enabled rapid cellular uptake, efficient endosomal escape, and functional cytosolic protein release into cells in media containing 10% serum. Moreover, nanoparticles encapsulating CRISPR-Cas9 ribonucleoproteins (RNPs) induced robust levels of gene knock-in (4%) and gene knockout (>75%) in several cell types. A single intracranial administration of nanoparticles delivering a low RNP dose (3.5 pmol) induced robust gene editing in mice bearing engineered orthotopic murine glioma tumors. This self-assembled polymeric nanocarrier system enables a versatile protein delivery and gene editing platform for biological research and therapeutic applications.

The median survival for glioblastoma patients is ~15 months despite aggressive surgery and radio-chemotherapy approaches. Thus, developing new therapeutics is necessary to improve the treatment of these invasive brain tumors, which are known to show high levels of the eukaryotic initiation factor, eIF4E, a potent oncogene. Ribavirin, the only clinically approved drug known to target eIF4E, is an anti-viral molecule currently used in hepatitis C treatment. Here, we report the effect of ribavirin on proliferation, cell cycle, cell death and migration of several human and murine glioma cell lines, as well as human glioblastoma stem-like cells, in vitro. In addition, we tested ribavirin efficacy in vivo, alone and in combination with temozolomide and radiation. Our work showed that ribavirin inhibits glioma cell growth and migration, and increases cell cycle arrest and cell death, potentially through modulation of the eIF4E, EZH2 and ERK pathways. We also demonstrate that ribavirin treatment in combination with temozolomide or irradiation increases cell death in glioma cells. Finally and most importantly, ribavirin treatment in vivo significantly enhances chemo-radiotherapy efficacy and improves survival of rats and mice orthotopically implanted with gliosarcoma tumors or glioma stem-like cells, respectively. On the basis of these results, we propose that ribavirin represents a new therapeutic option for glioblastoma patients as an enhancer of the cytotoxic effects of temozolomide and radiotherapy.