Magnetic hyperthermia, or the heating of tissues using magnetic materials, is a promising approach for treating cancer. We found that human mesenchymal stem cells (MSCs) isolated from various tissues and MSCs expressing the yeast cytosine deaminase::uracil phosphoribosyl transferase suicide fusion gene (yCD::UPRT) can be labeled with Venofer, an iron oxide carbohydrate nanoparticle. Venofer labeling did not affect cell proliferation or the ability to home to tumors. All Venofer-labeled MSCs released exosomes that contained iron oxide. Furthermore, these exosomes were efficiently endocytosed by tumor cells. Exosomes from Venofer-labeled MSCs expressing the yCD::UPRT gene in the presence of the prodrug 5-fluorocytosine inhibited tumor growth in a dose-dependent fashion. The treated tumor cells were also effectively ablated following induction of hyperthermia using an external alternating magnetic field. Cumulatively, we found that magnetic nanoparticles packaged into MSC exosomes are efficiently endocytosed by tumor cells, facilitating targeted tumor cell ablation via magnetically induced hyperthermia.

Antioxidative capabilities of carboxymethylated (1 → 3)-β-D-glucan from Saccharomyces cerevisiae cell wall, α-tocopherol, and mannitol against lipid peroxidation in phosphatidylcholine liposomes induced by OH· radicals produced with Fenton's reagent (H₂O₂/Fe²⁺) were studied using absorption ultraviolet-visible spectrophotometry. It was found that (1 → 3)-β-D-glucan is an antioxidant with the scavenging ability lying between that of α-tocopherol, which is known to be incorporated in the lipid bilayer, and the water-soluble antioxidant, mannitol.

Background: Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology. Magnetic nanoparticles for cancer therapy and diagnosis have been developed on the basis of their unique physico-chemical properties not prese...