| BackgroundAs the most common female cancer all over the world, cervical cancer is still a major cause of cancer related death in developing countries. As the most common adjuvant therapies of postoperative cervical cancer, chemotherapy often induces varies of adverse reactions while radioresistance often occurs during radiation therapy. Photothermal therapy is an emerging technique which exploits near infrared (NIR) laser light-generated heat to destroy tumor cells without inducing adverse reactions or radioresistance. In this paper, we have synthesized hollow gold nanospheres (HGNs) possessing a NIR absorption peak at a controlled wavelength which can promptly generate heat while accepting a corresponding wavelength laser irradiation with a lower dose energy. Here, we synthesized anti-cMet antibody conjugated HGNs (anti-cMet/HGNs) that targeted cMet (also known as hepatocyte growth factor receptor, HGFR), a member of the family of receptor tyrosine kinases. CMet was confirmed overexpressing on the cell membrane of multiple malignancies and markedly overexpressing on which of tumors with chemotherapy resistance. The utilization of anti-cMet/HGNs in photothermal therapy may mediate targeted cancer treatment and enhance treatment sensitivity.ObjectiveThe aim of our study was to investigate whether anti-cMet antibody conjugated hollow gold nanospheres (anti-cMet/HGNs) could enhance the sensitivity of photothermal ablation therapy on cervical cancer.MethodsThe successful synthesis of HGNs was observed and photographed by transmission electron microscope (TEM). The absorbance of naked HGNs and anti-cMet/HGNs was examined by UV-Visible-NIR spectrophotometry. Over-representation of cMet in cancer cells was verified by immunofluorescence. To test the toxicity of functionalized gold nanospheres using cell counting kit-8(CCK-8). Uptake of HGNs and anti-cMet/HGNs was tested by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The in vitro photothermal therapy was conducted in four groups-control, laser alone, naked HGNs with laser and anti-cMet/HGNs with laser using human cervical cancer cells-HeLa and CaSki. To investigate these four groups’ inhibitory rate of cell proliferation by CCK-8. The variation of apoptotic rate was observed by flow cytometry with a dual staining Annexin V-FITC/propidium iodide (PI) kit. The expression of apoptosis-related proteins was examined by western blot.Results:TEM showed us a shape of hollow spheres with an average diameter of 67.35nm and a mean wall thickness of 7.25nm. Modification with PEG and conjunction with targeting antibody made an approximately 20nm right shift of the largest infrared absorption peak (from 788nm to 808nm) of gold nanomaterials. Both two human cervical cancer cell lines- HeLa and CaSki-were detected a layer of fluorescent green marker. Correspondingly, ICP-AES confirmed the distinct uptake of anti-cMet/HGNs by both two cell lines. The maximum absorbed dose of both naked HGNs and conjugated HGNs appeared respectively after a 48h (HeLa) and 24h (CaSki) incubation. Compared with other three groups, anti-cMet/HGNs with laser (1.7J/cm2) possessed a higher inhibitory rate of cell proliferation by 34.8% in HeLa and 53.6% in CaSki while possessed a higher total apoptotic rate by 8.54% in HeLa and 31.6% in CaSki. Meanwhile this group was indicated an obviously overexpression of Caspase-3, Bax and Cyclin E2 and decreased expression of Bcl-2 in both two cell lines.ConclusionAnti-cMet/HGNs had potentials to enhancing the effect of low dose energy photothermal ablation therapy on cervical cancer by disrupting the balance between Bcl-2 and Bax. |
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