RESUMO
Magnetic Fe3O4 nanoparticles (MNPs) have shown promise as drug carriers for treating lung and liver tumors in vivo. However, little is known about the combined delivery of these MNPs with a second approach, extremely low frequency electro-magnetic field (ELFF) exposure, which has been shown to have value for in vitro treatment of tumor cells. Here, ELFF and MNPs were combined to treat healthy (HL-7702) and cancerous (Bel-7402, HepG2) hepatic cells lines to explore the potential therapeutic effects, bio-mechanisms, and potential toxicity of a combined drug-free treatment in vitro. Flow cytometry for anti-AFP (alpha fetal protein) antibody, which coated the MNPs, indicated that the combined treatment induced Bel-7402 and HepG2 hepatoma cells lines into early apoptosis, without significant effects on healthy hepatic cells. This effect appeared to be mediated through cellular membrane ion metabolism. The presence of AFP-loaded MNPs strengthened the effects of ELFF on tumor cells, inducing a higher frequency of early apoptosis, while having minimal toxic effects on healthy HL-7702 cells. Western blotting revealed that the apoptosis-triggering BCL proteins were up regulated in hepatoma cells compared to healthy cells. Flow cytometry and patch-clamp studies revealed that this resulted from a higher MNP uptake ratio and greater cellular membrane ion exchange current in tumor cells compared to HL-7702 cells. Further, patch-clamp results showed that combining MNPs with ELFF treatment induces cells into early apoptosis through an ion metabolism disturbance in cells, similar to ELFF treatment. In brief, the combination of ELFF and MNPs had beneficial effects on tumor cells without significant toxicity on healthy cells, and these effects were associated with cellular MNP uptake.
