The comparison of the apoptosis effects of titanium dioxide nanoparticles into MDA-MB-231 cell line in microgravity and gravity conditions

Objective (s): Gravity could affect some system features and perform directly as an organizing field factor. Recent investigations have examined the titanium dioxide nanoparticles (TiO2 NPs) in biomedical applications, mostly in the cancer treatment field. This study aimed to evaluate the effects of simulated microgravity combined with TiO2 NPs in MDA-MB-231 cells proliferation for the first time. In other words, this study examined the utility of the microgravity environment in nano-therapy. Materials and Methods: The MDA-MB-231 human breast cancer cell line and TiO2 NPs were purchased. The 2D clinostat was applied for the simulation of the microgravity. The morphological studies, MTT cytotoxicity assay, Acridine orange/Ethidium bromide double staining studies and flow cytometry analysis were utilized.Results: The MTT assay, the morphological studies, Acridine orange/Ethidium bromide double staining studies and flow cytometry analysis confirmed the apoptosis-inducing effect of microgravity in combination with TiO2 NPs. The IC50 of simulated microgravity in the presence of TiO2 NPs was determined to be 130 µM. Furthermore, MDA-MB-231 cells exposed to microgravity adopted a different phenotype. Conclusion: Based on our observation, although the relative mechanisms need to be explored further, microgravity can strictly affect the TiO2 NPs effects on MDA-MB-231 cells. The significance of this study lied in the fact that simulating microgravity can be a powerful physical cure for cancer therapy and open new horizons for the studies in the field of biology, biophysics, and medicine.