Bimodal Targeting Efficacy Of Nanoparticles（Fe₃O₄-Cy5.5-NGR） In Ovarian Cancer Xenografts

Objective To verify the targeting efficacy of nanoparticles（Fe₃O₄-Cy5.5-NGR） in human ES-2 ovarian cancer xenografts.Methods 1. Grouping:12 femal BALB/c mice（about 6 weeks, 20g） were marked and divided into 2 groups randomly. 2.Bimodel contrast agents were synthesized chemically with a Fe core and linked by Cy5.5 fluorescent dye on surface, then the experimental and control group molecular probes were accomplished by conjugating with PEG3500-NGR and only PEG3500, separately. Physical and chemical characters of Fe₃O₄-Cy5.5-NGR and Fe₃O₄-Cy5.5 were detected on several instruments, like TEM, flow cytometry, plate reader and so on. 3. ES-2 human ovarian cancer cells were cultured on Ma Coy’s 5A medium to a number of 6×107。4.Both experimental and control mice were injected 5×106 cells subcutaneously and the following texts carried on when tumors grew to a diameter of 8mm. 5. Fe₃O₄-Cy5.5-NGR and Fe₃O₄-Cy5.5 NPs were injected intravenously to mice and imagings were obtained from 7.0T MR and far-infrared fluorescence instrument to display nanoparticles’ targeting performance, distribution and metabolism in vivo. 6. Xenografts were cut down and stained for fluorescence and pathology.Result In vitro:1.Fe₃O₄-Cy5.5-NGR NPs is bigger and sharper than Fe₃O₄-Cy5.5 NPs on TEM. 2. After different concentrations of Fe₃O₄-Cy5.5-NGR（0.124-0.987mmol） and Fe₃O₄-Cy5.5（0.215-1.712mmol） nanoparticles co-cultured with ES-2 cells for 24 h, the cell vitality maintains at about 90% suggesting no cytotoxicity of both NPs. 3. The fluorescence intensity of experimental group at the concentrations of 40、80�'�160μmol is 3.1,1.65 and 1.26 times of control group, respectively.4. T2 relaxivity of Fe₃O₄-Cy5.5-NGR and Fe₃O₄-Cy5.5 is 155.49 m M-1S-1, 180.74 m M-1S-1. In vivo:1. MRI / NIRF showed Fe₃O₄-Cy5.5-NGR NPs got a significantly T2 and T2* signal reduce / fluorescent enhancement than Fe₃O₄-Cy5.5 NPs, especially at 24 h. While NIRF images suggested nanoparticals metabolizm out of body from 2h-24 h via blood circulation. 2. CSLM image shows the experimental group had brighter fluorescence around the nucleus at cytoplasm and cell membrane. 3.Xenografts showed significant cell pleomorphism of clear cell carcinoma after H&E staining.Conclusion The Fe₃O₄-Cy5.5-NGR NPs had stable properties and well targeting ability, which may provide help in early diagnosis of ovarian cancer and detection of small metastatic lesions.