In vitro and in vivo evaluation of anti-cancer activity: Shape-dependent properties of TiO₂ nanostructures

Cancer is a complex and widespread disease, and it is going to be the first cause of death in the world. Chemotherapy has been used to treat cancer, but it is detrimental to immune cells and known to induce numerous side effects. Therefore it is imperative to develop new drugs for the treatment of cancer without any side effects and toxicity. TiO₂ nanomaterials are human safe, cost effective, chemically stable and have numerous biomedical applications. Spherical TiO₂ fine particles (TFP), TiO₂ nanosquares (TNS) and TiO₂ nanotubes (TNT) were developed and evaluated for anti-cancer activity in vitro and in vivo. Our data suggest that these nanostructured materials significantly inhibited proliferation of breast cancer MDAMB 231 cells in in vitro shape dependent manner. In addition, we found that TiO₂ nanostructures inhibited the migration and colony formation of breast cancer MDAMB231 cells. More importantly, we found that TNS/TNT/TFP had anti-angiogenic effect in CAM assay and TNT had comparable anti-angiogenic effect with the positive control staurosporine. Additional qRT-PCR data suggest that TiO₂ nanostructures induced the upregulation of tumor suppressor genes p53, MDA7, TRAIL and transcription factor STAT3, which suggests the probable mechanism for the anticancer activity of TiO₂ nanostructures. Finally, analysis of TEM confirms the dispersion and interaction of nanostructures in the cells. Thus these materials could be potential therapeutic targets for the treatment of cancer.