Apoptosis selectively induced in BEL-7402 cells by folic acid-modified magnetic nanoparticles combined with 100 Hz magnetic field

Abstract

Jian Wen,1 Shulian Jiang,1 Zhiqiang Chen,1 Wei Zhao,1 Yongxiang Yi,1 Ruili Yang,1 Baoan Chen2 1Second Affiliated Hospital of Southeast University, 2Department of Hematology, Zhongda Hospital, Medical School, Southeast University, Nanjing, People's Republic of China Objective: To explore the effect of folic acid-modified magnetic nanoparticles (FA-MNPs) combined with a 100 Hz extremely low-frequency electromagnetic field (ELF-EMF) on the apoptosis of liver cancer BEL-7402 cells. Materials and methods: MNPs (20 nm) were prepared by coprecipitation, and then folic acid was coated onto MNPs to prepare FA-MNPs. BEL-7402 cells and HL7702 cells were selected as liver cancer cells and normal liver cells, respectively. The ELF-EMF was generated from a solenoid coil. Cellular uptake of NPs was determined by inductively coupled plasma atomic emission spectroscopy. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to evaluate cell inhibition. Apoptosis was analyzed by flow cytometry. Statistical analyses were performed using two-way analysis of variance. Results: FA-MNPs combined with a 100 Hz magnetic field significantly inhibited cell proliferation and induced higher apoptosis compared to either the ELF-EMF alone or FA-MNPs alone. FA-MNPs showed a better apoptosis effect and higher iron uptake in BEL-7402 cells compared to in HL7702 cells. On the basis of the ELF-EMF, higher doses of FA-MNPs brought higher apoptosis and higher iron uptake in either BEL-7402 cells or HL7702 cells. Conclusion: These results suggest that FA-MNPs may induce apoptosis in a cellular iron uptake-dependent manner when combined with an ELF-EMF in BEL-7402 cells.Keywords: extremely low-frequency magnetic field, magnetic nanoparticle, apoptosis, liver cancer, folic acid