Efficient delivery of PKN3 shRNA for the treatment of breast cancer via lipid nanoparticles.

Protein kinase N3 (PKN3), an AGC-family member, is often overexpressed in breast tumor cells. RNAi therapy is a promising approach to inhibit tumor growth by reducing the expression of PKN3. In this report, lipid nanoparticles encapsulated with new shRNA PKN3 (SS-LNP/shPKN3) with redox-responsiveness were developed in order to specifically down-regulate the expression of PKN3 for breast cancer treatment. The SS-LNP/shPKN3 was prepared by microfluidic method using disulfide bonds based ionizable lipid as main component. The as-prepared SS-LNP/shPKN3 lipid nanoparticles were characterized via using dynamic light scattering (DLS) and transmission electron microscopy (TEM). The results indicated that the obtained SS-LNP/shPKN3 exhibited uniform particle size and regular spherical morphology. Moreover, glutathione (GSH) triggered release of shPKN3 confirmed the redox-responsiveness of the SS-LNP/shPKN3. Finally, the anti-tumor effect of SS-LNP/shPKN3 was evaluated against MDA-MB-231 cells and derived xenograft tumor bearing mice. It was found that the SS-LNP/shPKN3-2 had the highest PKN3 protein inhibition rate of 60.8% and tumor inhibition rate of 62.3%. Taken together, the SS-LNP/shPKN3 might be a potential therapeutic strategy for breast cancer.