Preparation And Growth Inhibition Of 4T1 Breast Cancer Cells Of Doxorubicin-loaded PH/magenetic Dual-responsive Nanoparticles

Doxorubicin(Doxorubicin,DOX),one of the most important chemotherapy of leukemia,malignant lymphoma and breast cancer,can can enter tumor cells and embedded DNA molecules connected,which can inhibit DNA replication and synthesis,so as to achieve the purpose of inhibiting tumor growth.However,its application is limited due to the toxic effects of adriamycin on normal tissues and organs.New targeted and controlled release drug delivery systems ultilizing modern technologies,which targeted chemotherapeutics drug delivery to the treatment site,and local controlled release,minimizing toxicity,improve the therapeutic effect,increase patient compliance,is one of the important ways to decrease toxicity of chemotherapeutics.In this study,we used mesoporous silica materials,combined with Fe3O4 magnetic nanoparticles and pH responsive polymer materials to construct a new type of functional composite nanomaterials as doxorubicin carriers.The nanocomposite using mesoporous silica ordered pore structure,large specific surface area and pore volume,good biocompatibility and stability,surface functional characteristics,combined with the magnetic targeting of Fe3O4 nanoparticles and the drug release of pH responsive polymer PEG-b-PAsp,which may targeting delivery and controlled release doxorubicin,thus reducing toxicity and increasing the therapeutic of chemotherapeuticsThe main research content of this paper is divided into four parts:(1)Preparation,characterization and optimization of drug loading of Fe3O4@nSiO2@mSiO2@PEG-b-PAsp@DOX(DOX-NPs)(nanocomposite);(2)The inhibition of the proliferation of nanocomposite on breast cancer cell 4T1;(3)The inhibition of nanocomposite on 4TI breast cancer model;preliminary study;(4)Preliminary study on the inhibitory effect of nanocomposite on invasion and metastasis of breast cancer cell line 4T1.In the first part of the construction of composite nanoparticles,were synthesized Fe3O4 magnetic nanoparticles by hydrothermal method,coated Fe3O4 magnetic nanoparticles with a layer of solid silica(nSiO2)through the Stober method and sol-gel process improving the stability of Fe3O4 magnetic nanoparticles and modification,covered with a layer of mesoporous silica(mSiO2)in solid silicon by ethanol refluxing method,and aminalize its surface,that is composite carrier material Fe3O4@nSiO2@mSiO2.By using the good adsorption properties of mesoporous silica and the electrostatic binding of PEG-b-PAsp to doxorubicin,a high density magnetic mesoporous silica doxorubicin composite nanoparticles were prepared.We determine the optimal preparation conditions for C2B1A3D1 through orthogonal test on the preparation process,namely the carrier material dosage is 10 mg,the amount of PEG-b-PAsp was 4 mg,adriamycin dosage stirring time of 4 mg,after adding 1 h nanoparticles were prepared by loading up to 58.50%(±3.91%).The hysteresis curves at room temperature and the release curves under different pH conditions indicated that the drug loaded nanocomposite(DOX-NPs)had magnetic response and pH sensitive drug release characteristics.In the second part of the study we confirmed that the carrier material can be effectively uptake in 4T1 cells observing by transmission electron microscopy,biological fluorescence microscopy,and DOX-NPs can release DOX in cells,it has significant inhibitory effects on 4T1 cells,and there is a concentration dependent,the IC50 value is 1.284?g·mL-1 which is consistent with the selection of free drug.We resumed in the 4T1 breast cancer xenograft model in the third part of the research,the inhibition of tumor to tumor volume and tumor weight of DOX-NPs to evaluate the in vivo growth effect to pulmonary nodule number and surface area of the metastasis index to evaluate the anti metastasis effect.The results showed that DOX-NPs had a significant effect on inhibiting tumor growth,and the side effects were small.In the DOX-NPs group,the number of lung surface nodes was significantly less than that of the other groups,and the HE group was smaller than the other groups in the DOX-NPs group,which indicated that DOX-NPs could inhibit the lung metastasis of 4T1 cells.Based on the third part of the study,we found that DOX-NPs could inhibit the lung metastasis of 4T1 cells,and the possible mechanism was discussed.The results showed that DOX-NPs could inhibit the migration and migration of breast cancer cell line 4T1 by scratch assay and Transwell assay,and the inhibitory effect was enhanced with the increase of DOX-NPs concentration.Western Blot the experimental results show that the expression of related cell adhesion factor E-Cadherin and metastasis of tumor cells with the concentration of DOX-NPs decreased,while the expression of Vimentin with DOX-NPs concentration increasing,so that DOX-NPs can inhibit or reverse the breast cancer 4T1 cell epithelial mesenchymal transition(Epithelial-Mesenchymal Transition,EMT),4T1 and inhibit the growth and metastasis of breast cancer cells.The above results suggest the preparation of doxorubicin-loaded pH/magenetic dual-responsive nanoparticles,Fe3O4@nSiO2@mSiO2@PEG-b-PAsp@DOX,was successful.The results showed that nanocomposite has good effect of inhibiting the growth and metastasis of breast cancer 4T1 cells,achieving the purpose of reducing toxicity and efficiency.We also confirmed preliminarily that DOX-NPs can inhibit or reverse the EMT of breast cancer 4T1 cells.Above all,the nanocomposite has potential application in the field of tumor therapy.