Synthesis of Fructose-based Nanoparticles and Understanding Their Behaviors as Drug Carriers in Breast Cancer Therapy

Abstract

A library of fructose-based glycopolymers was synthesized via RAFT polymerization. Obtained amphiphilic block copolymers were utilized to prepare a series of nanoparticles of different sizes and structures by self-assembly. Some processing parameters like common solvent, hydrophobic chain length, water injection rate and temperature were investigated to achieve good control of morphologies. These fructose-coated nanoparticles exhibited breast cancer cell-specific uptake, which is heavily dependent on micelle size and attachment site of fructose moieties. Since the internalization of micelles by triple-negative breast cancer cells is much higher than by normal cells, these non-cytotoxic, fructose-coated micelles can be used for targeted drug delivery to triple-negative breast cancer. To optimize therapeutic efficacy, shape effect of fructose-coated nanoparticles on cellular uptake by two breast cancer cell lines (MCF-7 cells and MDA-MB-231 cells) in 2D and 3D cell culture models were investigated. The cytotoxicity of corresponding paclitaxel-loaded nanoparticles were tested as well to give a comprehensive comparison between cellular uptake and resulted therapeutic efficacy after drug encapsulation. Consistent results in 2D models confirmed the shape effect of nanoparticles on cellular uptake. Unexpectedly, the shape effect did not make a big difference in cell growth inhibition in 3D multicellular spheroids due to possible cessation of transcellular delivery of nanoparticles in the apoptotic peripheral cells, caused by faster release of drugs from uncrosslinked micelles. To understand this process, the location of hydrophobic drugs after encapsulation was investigated. Curcumin, which is a model drug, was encapsulated into nanoparticles during self-assembly. Our results reveal that curcumin is preferentially located in the hydrophilic shell of nanoparticles, suggesting interaction between curcumin and fructose moieties. In addition, the influence of length and stiffness, which are important parameters of rod-like nanoparticles, were also investigated in cellular uptake studies. Cellular uptake of different rod-like micelles by breast cancer cells in 2D and 3D models indicate that internalization of rod-like micelles are significantly affected by the stiffness of nanoparticles, though lengths of rods also play an important role. These results will provide fundamental new knowledge on the role of size, shape and stiffness in developing more efficient, better penetrating nanocarriers for anticancer drug delivery.