The therapeutic effect of PEI-Mn0.5Zn0.5Fe2O4 nanoparticles/pEgr1-HSV-TK/GCV associated with radiation and magnet-induced heating on hepatoma

Comprehensive therapy based on the integration of hyperthermia, radiation, gene therapy and chemotherapy is a promising area of study in cancer treatment. Using PEI-Mn0.5Zn0.5Fe2O4 nanoparticles (PEI-MZF-NPs) as a gene transfer vector, the authors transfected self-prepared pEgr1-HSV-TK into HepG2 cells and measured the expression of the exogenous gene HSV-TK by RT-PCR. The results showed that HSV-TK was successfully transfected into HepG2 cells and the expression levels of HSV-TK remained stable. Besides, PEI-MZF-NPs were used as magnetic media for thermotherapy to treat hepatoma by magnet-induced heating, combined with radiation-gene therapy. Both in vitro and in vivo results suggest that this combined treatment with gene, radiation and heating has a better therapeutic effect than any of them alone. The apoptotic rate and necrotic rate of the combined treatment group was 51.84% and 15.45%, respectively. In contrast, it was only 20.55% and 6.80% in the radiation-gene group, 7.49% and 3.62% in the radiation-alone group, 15.23% and 7.90% in the heating-alone group, and only 3.52% and 2.16% in the blank control group. The inhibition rate of cell proliferation (88.5%) of the combined treatment group was significantly higher than that of the radiation-gene group (59.5%), radiation-alone group (37.6%) and heating-alone group (60.6%). The tumor volume and mass inhibition rate of the combined treatment group was 94.45% and 93.38%, respectively, significantly higher than 41.28% and 33.58% of the radiation-alone group, 60.76% and 52.18% of the radiation-gene group, 79.91% and 77.40% of the heating-alone group. It is therefore concluded that this combined application of heating, radiation and gene therapy has a good synergistic and complementary effect and PEI-MZF-NPs can act as a novel non-viral gene vector and magnetic induction medium, which offers a viable approach for the treatment of cancer.