Evaluation of glioblastoma (U87) treatment with ZnO nanoparticle and X-ray in spheroid culture model using MTT assay

Background: Glioblastoma is the most serious brain tumor that is often incurable with surgery. Chemotherapy and radiation have also been unable to increase viability. Metal oxides nanoparticles such as zinc oxide (ZnO) are new techniques as anticancer agents that offer new hope in the treatment of cancers. We aimed to assess viability of glioblastoma cell lines U87 with spheroid culture model with a mean diameter of 350 µm using ZnO nanoparticles with 2, 4, and 6 Gy doses of X-Ray. Methods: The spheroids in 8 groups including control group, the group irradiating with 2, 4, and 6 Gy doses of X-Ray, the group receiving only ZNO nanoparticles, and groups receiving radiation plus nanoparticles ZnO (Zno+2 Gy,Zno+4 Gy,Zno+6 Gy) were assessed. After cells treatment with nanoparticles for about 68 h (one VDT=Volume Doubling Time), and radiation to the groups should be given especial doses with an accelerator 6 MV, the results were finally assessed by MTT assay test with 8000 and 10,000 cells densities. Results: ZnO nanoparticle was alone more effective than irradiating with 2, 4, or 6 Gy doses of X-ray 6 MV to treat the MGU87 cells. After treating cells with ZnO nanoparticle for one VDT and delivering 2, 4, and 6 Gy doses of X-ray using an accelerator 6 MV, the viability of the cells remained unchanged (p>0.05). Also, by adding ZnO nanoparticles to cell culture medium, it was achieved a better reduction of viability in the density of 8000 cells than in the density of 10,000 cells. Most importantly, this percentage reduction of viability in the group received ZnO nanoparticles alone with the density of 8000 cells was more than compared to the density of 10,000 cells. The difference between groups and the group received radiation with 6 Gy dose of X-Ray group with the density of 8000 cells was significant (p<0.05). Conclusion: In treatment of glioblastoma cell lines U87, using ZnO nanoparticles with the density of 10 mM can be an alternative for 2, 4, and 6 Gy doses of X-ray 6 MV. This result is very important for the protection of normal tissues to radiation therapy. Adding 2, 4, and 6 Gy doses of X-ray after treating ZnO nanoparticles for one VDT did may not lead to higher efficiency of ZnO nanoparticles. - Highlights: • MGU87 cells (spheroid 350 µm) treated with ZNO nanoparticles for 68 h (1 VDT). • Difference between 6 Gy and zno groups in density of 8000 cells was significant. • ZnO more effective than the 2, 4, and 6 Gy doses of X-Ray in the treatment of MGU87. • That is very important because of the protection of normal tissues to radiation. • Treated cells with ZnO and 2,4,and 6 Gy, viability not be significantly changed