Aminosilanized flower-structured superparamagnetic iron oxide nanoparticles coupled to 131I-labeled CC49 antibody for combined radionuclide and hyperthermia therapy of cancer

Combined radionuclide therapy with magnetic nanoparticles-mediated hyperthermia has been under research focus as a promising tumor therapy approach. The objective of this study was to investigate the potential of I-131-radiolabeled superparamagnetic iron oxide nanoparticles (SPIONs) prepared as the similar to 40 nm flower-shaped structures with excellent heating efficiency (specific absorption rate at H-0 = 15.9 kA.m(-1) and resonant frequency of 252 kHz was 123.1 W.g(-1)) for nano-brachytherapy of tumors. I-131-radiolabeled CC49 antibody attached to SPIONs via reactive groups of 3-aminopropyltriethoxysilane (APTES) provided specificity and longlasting localized retention after their intratumoral application into LS174T human colon adenocarcinoma xenografts in NOD-SCID mice. The results demonstrate feasibility and effectiveness of magnetic hyperthermia (HT), radionuclide therapy (RT) and their combination (HT + RT) in treating cancer in xenograft models. Combined therapy approach induced a significant (p < 0.01) tumor growth suppression in comparison to untreated groups presented by the tumor volume inhibitory rate (TVIR): 54.38%, 68.77%, 73.00% for HT, RT and HT + RT, respectively in comparison to untreated group and 48.31%, 64,62% and 69,41%, respectively, for the SPIONs-only injected group. Histopathology analysis proved the necrosis and apoptosis in treated tumors without general toxicity. Obtained data support the idea that nano-brachytherapy combined with hyperthermia is a promising approach for effective cancer treatment.