Background: siRNAs hold a great potential for cancer therapy, however, poor stability in body fluids and low cellular uptake limit their use in the clinic. To enhance the bioavailability of siRNAs in tumors, novel, safe, and effective carriers are needed. Results: Here, we developed cationic solid lipid nanoparticles (cSLNs) to carry siRNAs targeting EphA2 receptor tyrosine kinase (siEphA2), which is overexpressed in many solid tumors including prostate cancer. Using DDAB cationic lipid instead of DOTMA reduced nanoparticle size and enhanced both cellular uptake and gene silencing in prostate cancer cells. DDAB-cSLN showed better cellular uptake efficiency with similar silencing compared to commercial transfection reagent (Dharmafect 2). After verifying the efficacy of siEphA2-loaded nanoparticles, we further evaluated a potential combination with a histone lysine demethylase inhibitor, JIB-04. Silencing EphA2 by siEphA2-loaded DDAB-cSLN did not affect the viability (2D or 3D culture), migration, nor clonogenicity of PC-3 cells alone. However, upon co-administration with JIB-04, there was a decrease in cellular responses. Furthermore, JIB-04 decreased EphA2 expression, and thus, silencing by siEphA2-loaded nanoparticles was further increased with co-treatment. Conclusions: We have successfully developed a novel siRNA-loaded lipid nanoparticle for targeting EphA2. Moreover, preliminary results of the effects of JIB-04, alone and in combination with siEphA2, on prostate cancer cells and prostate cancer tumor spheroids were presented for the first time. Our delivery system provides high transfection efficiency and shows great promise for targeting other genes and cancer types in further in vitro and in vivo studies.

A new platform for drug, gene and peptide-protein delivery is emerging, under the common name of “extracellular vesicles”. Extracellular vesicles (EVs) are 30-1000 nm-sized cell-derived, liposome-like vesicles. Current research on EVs as nano-delivery systems for small-molecule drugs and genetic material, reveal that these tiny, biologically-derived vesicles carry a great potential to boost the efficacy of many therapeutic protocols. Several features of EVs; from efficacy to safety, from passive to active targeting ability, the opportunity to be biologically or chemically labelled, and most importantly, their eobiotic origin make them promising candidate for development of the next generation personalized nanomedicines. The aim of this article is to provide a view on the current research in which EVs are used as drug/genetic material delivery systems. Their application areas, drug loading and targeting strategies, and biodistribution properties are discussed.This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.