Multifunctional nanoparticles recruiting hyaluronic acid ligand and polyplexes containing low molecular weight protamine and ATP-Sensitive DNA motif for doxorubicin delivery

Nanoparticles (NPs) that combine stimuli-triggered drug release and active targeting of tumors signify a dual smart strategy in chemotherapeutic inhibition of cancer growth. Recently, low molecular weight protamine (PrtLMW) has been utilized to replace its precursor protamine (Prt) in the clinic, as it exhibits less undesirable side effects. In this study, we compared the merits of using Prt and PrtLMW to assemble two NPs. Anticancer drug doxorubicin (Dox) was loaded into ATP-binding aptamer (AptATP), a DNA sequence that undergoes a conformational change when exposed to an Adenosine-5′-triphosphate (ATP) rich environment. Dox-AptATP then complexed with the positively charged Prt or PrtLMW, and the resulting cationic, condensed core was further coated with high molecular weight hyaluronic acid (HAHMW), a known ligand for tumor marker CD44. The resulting two NPs were characterized then inspected for selective uptake and release in CD44 overexpressing breast cancer cells (MDA-MB-231) using flow cytometry. The localization of the released Dox in the cytosol and nuclei of the cells was confirmed by confocal microscopy. A dose-dependent cytotoxic effect was observed by performing MTT assay. Annexin-V FITC apoptosis assay showed that the NPs were able to induce apoptosis efficiently. The replacement of Prt with PrtLMW proved to be beneficial in increasing the release rate of Dox, and it exhibited a substantially increased cytotoxic effect on the treated cancer cells.