- Bäumer, Nicole;
- Tiemann, Jessica;
- Scheller, Annika;
- Meyer, Theresa;
- Wittmann, Lisa;
- Suburu, Matias Ezequiel Gutierrez;
- Greune, Lilo;
- Peipp, Matthias;
- Kellmann, Neele;
- Gumnior, Annika;
- Brand, Caroline;
- Hartmann, Wolfgang;
- Rossig, Claudia;
- Müller-Tidow, Carsten;
- Neri, Dario;
- Strassert, Cristian A;
- Rüter, Christian;
- Dersch, Petra;
- Lenz, Georg;
- Koeffler, H Phillip;
- Berdel, Wolfgang E;
- Bäumer, Sebastian
The small arginine-rich protein protamine condenses complete genomic DNA into the sperm head. Here, we applied its high RNA binding capacity for spontaneous electrostatic assembly of therapeutic nanoparticles decorated with tumour-cell-specific antibodies for efficiently targeting siRNA. Fluorescence microscopy and DLS measurements of these nanocarriers revealed the formation of a vesicular architecture that requires presence of antibody-protamine, defined excess of free SMCC-protamine, and anionic siRNA to form. Only these complex nanoparticles were efficient in the treatment of non-small-cell lung cancer (NSCLC) xenograft models, when the oncogene KRAS was targeted via EGFR-mediated delivery. To show general applicability, we used the modular platform for IGF1R-positive Ewing sarcomas. Anti-IGR1R-antibodies were integrated into an antibody-protamine nanoparticle with an siRNA specifically against the oncogenic translocation product EWS/FLI1. Using these nanoparticles, EWS/FLI1 knockdown blocked in vitro and in vivo growth of Ewing sarcoma cells. We conclude that these antibody-protamine-siRNA nanocarriers provide a novel platform technology to specifically target different cell types and yet undruggable targets in cancer therapy by RNAi.