Direct Comparison of Poly(ethylene glycol) and Phosphorylcholine Drug-Loaded Nanoparticles In Vitro and In Vivo.

Phosphorylcholine is known to repel the absorption of proteins onto surfaces, which can prevent the formation of a protein corona on the surface of nanoparticles. This can influence the fate of nanoparticles used for drug delivery. This material could therefore serve as an alternative to poly(ethylene glycol) (PEG). Herein, the synthesis of different particles prepared by polymerization-induced self-assembly (PISA) coated with either poly(ethylene glycol) (PEG) or zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was reported. The anticancer drug 4-(N-(S-penicillaminylacetyl)amino) phenylarsenonous acid (PENAO) was conjugated to the shell-forming block. Interactions of the different coated nanoparticles, which present comparable sizes and size distributions (76-85 nm, PDI = 0.067-0.094), with two-dimensional (2D) and three-dimensional (3D) cultured cells were studied, and their cytotoxicities, cellular uptakes, spheroid penetration, and cell localization profiles were analyzed. While only a minimal difference in behaviour was observed for nanoparticles assessed using in vitro experiment (with PEG-co- PENAO-coated micelles showing slightly higher cytotoxicity and better spheroid penetration and cell localization ability), the effect of the different physicochemical properties between nanoparticles had a more dramatic effect on in vivo biodistribution. After 1 h of injection, the majority of the MPC-co-PENAO-coated nanoparticles were found to accumulate in the liver, making this particle system unfeasible for future biological studies.

Direct Polymerization of the Arsenic Drug PENAO to Obtain Nanoparticles with High Thiol-Reactivity and Anti-Cancer Efficiency.

PENAO (4-(N-(S-penicillaminylacetyl)amino) phenylarsonous acid), which is a mitochondria inhibitor that reacts with adenine nucleotide translocator (ANT), is currently being trialed in patients with solid tumors. To increase the stability of the drug, the formation of nanoparticles has been proposed. Herein, the direct synthesis of polymeric micelles based on the anticancer drug PENAO is presented. PENAO is readily available for amidation reaction to form PENAO MA (4-(N-(S-penicillaminylacetyl) amino) phenylarsonous acid methacrylamide) which undergoes RAFT (reversible addition-fragmentation chain transfer) polymerization with poly(ethylene glycol methyl ether methacrylate) as comonomer and poly(methyl methacrylate) (pMMA) as chain transfer agent, resulting in p(MMA)-b-p(PEG-co-PENAO) block copolymers with 3-15 wt % of PENAO MA. The different block copolymers self-assembled into micelle structures, varying in size and stability (Dh = 84-234 nm, cmc = 0.5-82 µg mol-1) depending on the hydrophilic to hydrophobic ratio of the polymer blocks and the amount of drug in the corona of the particle. The more stable micelle structures were investigated toward 143B human osteosarcoma cells, showing an enhanced cytotoxicity and cellular uptake compared to the free drug PENAO (IC50 (PENAO) = 2.7 ± 0.3 µM; IC50 (micelle M4) = 0.8 ± 0.02 µM). Furthermore, PENAOs arsonous acid residue remains active when incorporated into a polymer matrix and conjugates to small mono and closely spaced dithiols and is able to actively target the mitochondria, which is PENAO's main target to introduce growth inhibition in cancer cells. As a result, no cleavable linker between drug and polymer was necessary for the delivery of PENAO to osteosarcoma cells. These findings provide a rationale for in vivo studies of micelle M4 versus PENAO in an osteosarcoma animal model.