12 T high static magnetic field suppresses osteosarcoma cells proliferation by regulating intracellular ROS and iron status.

Many studies indicated that static magnetic fields (SMFs) have anti-cancer effects. However, effect of SMFs on cancer cells with strength exceeding 12 T are rarely reported. The intracellular iron could participate in the reactive oxygen species (ROS) production and affect cell proliferation. This study aimed to investigate the effect of 12 T high static magnetic field (HiSMF) on osteosarcoma cells and the relationship with intracellular iron. The 12 T HiSMF was generated by a superconducting magnet. The proliferation was evaluated by CCK-8 assays and cell counting. The apoptosis, cell cycle distribution, and ROS were evaluated by flow cytometry. Intracellular iron status was evaluated by atomic absorption spectroscopy and Calcein-AM/2,2'-bipyridyl. The expression of cell cycle and iron metabolism-related genes were analyzed by Western Blot. The result showed that 12 T HiSMF exposure suppressed the proliferation of osteosarcoma cell lines MNNG/HOS, U-2 OS, and MG63 via cell cycle arrest in S and G2/M. Meanwhile, 12 T HiSMF increasing intracellular ROS, and its antitumor effect was reduced by antioxidant. Furthermore, the intracellular total and free iron levels, the expression of FTH1 and DMT1 were increased by 12 HiSMF. The iron chelator (DFO) could reduce the cytotoxicity of 12 T HiSMF on osteosarcoma cells. Moreover, 12 T HiSMF could enhance the cytotoxicity of cisplatin and sorafenib in osteosarcoma cells. In Conclusion, 12 T HiSMF could suppress osteosarcoma cells proliferation via intracellular iron and ROS related cell cycle arrest, and have application potential in osteosarcoma therapy combined with sorafenib and cisplatin.