Study On The Toxicity Of Fe₃O₄ Nanoparticles And Reversal Of Drug Resistance On Breast Cancer Cell Lines In Vitro

Objective To investigate the effects of three different sizes of Mg NPs-Fe3O4 on the toxicity of breast cancer cells, and its role in reversing the multidrug resistance in breast cancer cells, and to explore its mechanism.Methods(1)The cytotoxicity of the three different sizes of 7nm, 9nm, 11 nm of Mg NPs-Fe3O4 on MCF-7 cells was determined using the CCK8 assay and Ed U assay. Cell apoptosis and cell cycle was monitored by flow cytometry. The intracellular localization of Mg NPs-Fe3O4 was detected by TEM. The oxidative damage of different sizes of Mg NPs-Fe3O4 on MCF-7 cells was monitored by glutathione assay and reactive oxygen species assay. Expression of the oxidative stress associated gene and protein was determined by real-time PCR and Western Blotting.(2) MCF-7/ADR cells were divided into control group, Mg NPs-Fe3O4 group, EPI group and EPI+ Mg NPs-Fe3O4 group. Inhibitory effect on the proliferation of MCF-7/ADR cells was evaluated by CCK8 method.Cell apoptosis was detected by Hoechst33342.The expression levels of ABCB1, ABCG2 m RNA was detected by real-time PCR.The alteration of P-gp, BCRP protein expression was detected by western blotting.Results(1)TEM image results showed that all three sizes of Mg NPs-Fe3O4 were incorporated into MCF-7 cells. The effect of all three kinds of Mg NPs-Fe3O4 on cell proliferation, cell apoptosis and cell cycle was in a dose-dependent manner, especially in 9nm group.Detection of glutathione and reactive oxygen shows that Mg NPs-Fe3O4 can induce oxidative damage in MCF-7 cells. Real-time PCR and Western Blotting showed that the gene and protein of HO-1, GCLC and GCLM upregulated in different degree.(2) 20?g/m L Mg NPs-Fe3O4 effectively enhanced the cytotoxicity of EPI of MCF-7/ADR cells, increased apoptosis rate, whereas Mg NPs-Fe3O4 alone produced no cytotoxicity against MCF-7/ADR cells.Compared with the single drug group, Mg NPs-Fe3O4 combined with EPI group downregulated the expression of multidrug resistance genes ABCB1, ABCG2 and multidrug resistance protein P-gp, BCRP.Conclusion(1) The three different sizes of Mg NPs-Fe3O4 could inhibit cell proliferation, increase cell apoptosis and induce S-phase arrest, possibly through promoting cell oxidative damage, especially in 9nm group.(2) Mg NPs-Fe3O4 combined with EPI could downregulate expression of ABCB1, ABCG2 genes and protein P-gp, BCRP, and reverse resistance of breast cancer cells to epirubicin chemotherapy drug sensitivity.