Study On Construction Of Targeted-nanoparticles And Its Regulation Of Angiogenesis And Epithelial-mesenchymal Transition In Lung Cancer Cell In Molecular Imaging

Objective: In this study, we developed a kind of multi-mode molecular imaging nano-probes based on dendrimer-entrapped gold nanoparticles(Au DNEPs), aiming to realize the CT/MR/optical multi-mode imaging of non-small cell lung cancer(NSCLC) cells, and to test the SLUG and BMX gene expression in NSCLC cells and the effect of SLUG si RNA in knocking down the related gene expression to inhibit tumor growth. It may contribute to the further development of Gd-Au DENPs as gene vehicles carrying si RNA to be able to the promising dual-functional nano-probes in both targeted imaging and gene therapy.Methods:We have synthesized the Au DENPs modified with folic acid(FA). Based on these nanoparticles, in this study, we linked Gd and cy5.5 onto Au DENPs-FA as the multi-mode molecular imaging nano-probes of CT/MR/optical imaging for cancer cells. Then the CT, MR, and optical imaging system were respectively used to test the ability of the probes for the targeted imaging of NSCLC cells in vitro and in vivo. Immunohistochemistry(IHC) and western blotting methods were performed for testing BMX and SLUG gene expression of NCI-H460 NSCLC cells. RT-PCR and western blotting was used to test the effect of the SLUG si RNA for target gene knockdown in vitro and in vivo.Results:IHC and western blotting both confirmed that both BMX and SLUG gene express in NCI- H460 cells. MR imaging at different time points(before injection and 2, 4, 12, 24 hours respectively after injection of the nano-probes) showed that enhanced T1-weighted signal indensity of the tumor region gradually increase after injection of the probes, and reach the peak at 4 hours after injection, then gradually reduce. Excitation light intensity in tumor region of nude mouse immediately reached the peak after injection of the probes, then gradually decrease as the time passing, till to 6 hours after injection. Respectively after 24 hours and 48 hours transfection of the si RNA, results of the detection for m RNA and protein expressed of SLUG of the treated cells indicated that the customized si RNA named fragment 1 provide the best knockdown effect for target gene. So, we seleted fragment 1 as si RNA agent for the in vivo gene treatment on NSCLC xenograft mice. Results showed that the tumor growth of the treated group is less than that of the control group, as well as the protein expressed of SLUG.Conclusions:The Gd-Au DENPs-cy5.5 we synthesized, have a good CT/MR imaging ability. Both BMX and SLUG gene express in NCI-H460 NSCLC cells. Gd-Au DENPs- cy5.5 have a good imaging ability. The SLUG si RNA we designed and synthesized, has a ideal target gene knockdown effect for NCI-H460 cells in vitro and in vivo.