Investigation On Hyperthermia Mediated By Immuno Gold Nanocages Induces Apoptosis Of Human Breast Cancer

Objective: Being shone by laser light, Gold Nanocages can absorb the light energy and transform it into heat energy to kill tumor cells. Based on this characteristic of Gold Nanocages, we observe the cytotoxicity of Gold Nanocages, which is connected by CK19 antibody, and investigate its lethal effect on breast cancer cells. Through this experiment, we also detect the discrepancy of lethal effect on MCF-7, MDA-MB-231, MCF-7/TMA. We also detect the quantity of caspase-9 protein expression and explore its signaling pathways of this process. This experiment is expected to provide the corresponding theory basis for the further research and application of nanoparticles.Methods: Verified by immunohistochemical method to detect the CK19 antigen were expressed on MCF- 7 cell membrane surface. Nanocages which was connected to Anti- antibody of CK19 were made into nanostructures which have biological target of life activity. Immuno Au nanocages antibody probe was link to cell and shone with a laser which power density is 1.5 W/cm2 and its wavelength is 808 nm irradiation for 30 min. To observe the immune gold nanoparticle cage solar-thermal effect to kill your breast cancer cells by Fluorescence microscope. We use flow cytometry instrument to test the differences effect on three kinds of breast cancer cell. Immunohistochemical method was used to test the amount of caspase- 9 protein expression in breast cancer cells under different concentration of nano cage after heat treatment. By four methyl azo thiazole blue colorimetric method to observe the different toxicity on MCF- 7 cell in different concentration of the nanocage.Results: Antigen of CK19 high expressed in MCF- 7 cell membrane were confirmed by using the method of immunohistochemical in this experiment. Immune goldnanoparticle cage can significantly improve the effect of temperature to kill breast cancer cells. Apoptosis rate induced by photothermy do not have significant differences between in MCF- 7, MCF- 7 / TAM and MDA- MB – 231(F=0.84,P=0.456). When the temperature is 37 ℃, the expression quantity of caspase-9 protein is very low. When it is below 43 ℃, with the increase of temperature the expression of caspase – 9 increased significantly(F=14.914,P=0.000). High dose of immune gold nano cage can inhibits the proliferation of breast cancer cells(F=5.774,P=0.000). And it has time-effect(F=42.378,P=0.000)and dose- effect(F=76.440,P=0.000)relationship.Conclusons:(1) The experiment confirmed that CK19 antigen was highly expressed in MCF- 7 cell membrane.(2) Thermal therapy induced by immuno Au nanocages effected by laser can targeted killing breast cancer cells. This experiment also conformed that laser its power density in 1.5 W/cm2, wavelength in 808 nm is safe for normal breast cancer cells.(3)Increase the expression of caspase- 9 is one of mechanism mediated by immuno Au nanocages inducting breast cancer cell apoptosis.(4) There is irrelevant between the heat effect mediated by immuno Au nanocages cage and resistance or whether estrogen receptor positive cells were.