Epidermal Growth Factor-Ferritin H-Chain Nanoparticles As Nanocarrier Of Doxorubicin For Overcoming Drug Resistance In Human Breast Cancer Cells

Cancer is the most serious disease to people’s health at the present. In developed countries, cancer causes mortality rank only second to cardiovascular disease.In China,the mortality rate of cancer also in the rapid growth year by year. Currently the main therapies for cancer are surgery and chemotherapy.However, toxic side effects of chemotherapy drugs and cancer cells’drug resistance are major obstacles in cancer therapy. The main purpose of this study is to prepare a targeted, highly bio-safty human epidermal growth factor-ferritin heavy chain subunits drug delivery system (DOX/EGF-5Cys-FTH1),using the epidermal growth factor receptor (EGFR) which is overexpression in many cancer cells’membrane surface as targeting ligand to overcome multidrug resistance cell line-human breast cancer cell lines MCF-7/ADR.Besides,we also research the prepared nano drug delivery system to reverse the multidrug resistance of MCF-7/ADRA cells and its mechanism.In our study,we first constructed the targeting ferritin nano drug delivery system.Ferritin(FTH1) is a kind of natural protein that widely exist in human,animal and plant body. Thus it has high biosafy.Epidermal growth factor receptor(EGFR) is overexpressed in many malignant tissues and has been used as a therapeutic target for cancer treatment.Herein,a genetic method is shown to generate EGF-FTH1 chimeric proteins.Besides we found a simpler way to express the fusion proteins.However the internal space of ferritin is too small to load many drugs.To solve the problem,we first inserted a linker containing more sulfydryl sits (cysteine) into EGF-FTH1 by gene mutaion.Then adopt chemistry way to covalent bonding the doxorubicin to the nanoparticles to enhance the loading capacity. It was found that 72 of doxorubicin molecular could be loaded to one nanoparticle, and they could be released from the nanoparticles at pH5.0. In addition, the resulted DOX/EGF-FTH1 nanoparticles with a small size (-12nm) and narrow size distribution could specifically bind and taken up more by the MCF-7/ADR compared to free doxorubicin and doxorubicin loaded non-targeted ferritin-based nanoparticles. Besides we did detailed research on the mechanism of the nanoparticles anti drug resistance cells. The whole process might be ascribled to the following:1) DOX/EGF-5Cys-FTH1 nanoparticles can carry more DOXs into the cells by receptor-mediated endocytosis;12) DOX/EGF-5Cys-FTH1 nanoparticles can be accumulated in lysosome rapidly after their internalization, which leads to fast drug releasing; 3) More released free DOXs can be observed in nuclei, and they can change the cell cycle, damage the nuclei, and then cause the cell death.These results demonstrate that the DOX/EGF-XCys-FTHl as a new nano carrier system could be a very promising drug delivery system in targeted cancer therapy and also provide some theometical reference for the development of clinical research.