Abstract: Objective To explore whether superparamagnetic iron oxide nanoparticle (SPIO) will influence the anti-tumor immunity triggered by tumor lysate protein against human MCF-7 breast cancer cells (MCF-7) in vitro. Methods SPIO was covalently conjugated with tumor lysate protein to form SPIO-protein complex. Human peripheral blood mononuclear cells (PBMC) were stimulated by tumor lysate protein, SPIO, or SPIO-protein complex separately. The treated PBMC were mixed with MCF-7 cells, and tumor inhibition was evaluated by MTS assay. Results The SPIO conjugated with 60% of tumor lysate protein and formed a larger nano-structure. Compared with tumor lysate protein, SPIO-protein complex significantly enhanced the anti-tumor response by PBMC, whereas SPIO alone produced no cytotoxicity against MCF-7 cells. Conclusions The SPIO-protein complex is capable of enhancing the anti-cancer immune reaction against MCF-7 cancer cells by PBMC in vitro.

Key words: SPIO nanoparticle, tumor lysate protein, immunotherapy, MCF-7 cells