Hyaluronic acid (HA) has inherent ability to target the CD44 receptors and internalize into tumour cells via receptor-mediated endocytosis. Therefore, conjugation of this natural linear polysaccharide to polymeric NPs or micelles, as one of the most promising approaches, could be useful for future clinical applications such as drug delivery. Accordingly, we report on the synthesis of mitoxantrone (MTX)-conjugated polymeric nanoparticles (NPs) composed of polyethylene glycol-HA (PEG-HA) for MTX delivery toward special tumour cells. To determine the size of the polymeric NPs, field emission scanning electron microscopy (FESEM) and particle size analyzer system Zetasizer_nanoZS were employed. The in vitro cytotoxicity analysis of MTX-loaded HA-PEG NPs and free MTX against two cell lines with different levels of CD44 expression (MDA-MB-231 (very high) and MCF-7 (low) was conducted by MTT assay. Also, computational molecular docking was employed to study in detail the active site residues and the critical interactions between HA-EDA-PEG-EDA-MTX NPs and CD44 receptor. The particle size analysis and electron microscopy showed the average size of polymeric NPs less than 350 nm. FT-IR spectrophotometry analysis and also NMR confirmed the conjugation of HA and MTX onto the PEG. Cytotoxicity assay revealed that the engineered polymeric NPs were able to specifically bind to and significantly inhibit the CD44 receptor-positive MDA-MB-231 cells, but not the CD44-negative MCF-7 cells. Furthermore, analysis of the binding modes revealed that for the best-docked pose nearly 10 conventional hydrogen bond can occur between the MTX-EDA-PEG-EDA-HA NPs and amino acids of CD44 receptor. Based on these findings, we suggest the HA-PEG-MTX NPs as an effective functional-targeted nanomedicine toward therapy of CD44-positive cancers.
Keywords: Hyaluronic acid; MTT assay; mitoxantrone; molecular docking; polymeric nanoparticles.