Potential application of titanium dioxide nanoparticles in the prevention of osteosarcoma and chondrosarcoma recurrence.

Osteosarcoma and chondrosarcoma are malignant bone tumors, and they significantly affect the life quality of patients including children and adults. The main treatment method is surgical amputation of the malignant lesion, despite that recurrence often occurs. Recently, it has been observed that TiO2 NPs killed HeLa cells effectively via photocatalysis in vitro, which indicates titanium dioxide (TiO2) nanoparticles (NPs) might be used to reduce the recurrence of osteosarcoma and chondrosarcoma by inducing cytotoxicity to bone tumor cells. In this study, we investigated the potential effects of TiO2 NPs in two cancer cell lines in vitro: U-2 OS (osteosarcoma) and SW 1353 (chondrosarcoma). We assessed cell viability, the levels of reactive oxygen species (ROS) and glutathione (GSH) after exposure to TiO2 NPs at different concentrations (0.1-100 microg/ml) for varying exposure periods (12-48 hours). Compared to the NP-free control, TiO2 NPs induced cell death in a dosage-dependent and time-dependent manner. The median inhibitory concentration (IC50) of TiO2 NPs at 24 hours was 211.3 +/- 15.2 microg/ml and 5408.8 +/- 45.9 microg/ml for SW 1353 and U-2 OS cell lines, respectively. TiO2 NPs concentrations above 1 microg/ml were more efficient to reduce the cell viability of SW 1353 than U-2 OS of NPs at all exposure times. The increased ROS and reduced GSH levels indicated that TiO2 NPs killed cancer cells through oxidative stress. These results suggested that the TiO2 NPs can be potentially used to minimize/prevent the recurrence of osteosarcoma and chondrosarcoma.