Construction Of A Multifunctional Visualized Intelligent Nanosystem For Its Therapy Study On Chemoresistant ER-positive Breast Cancer

Background: Breast cancer is the most common cancer in women,and ER?-positive breast cancer accounts for the main proportion.Chemotherapy is one of the main treatments for ER?-positive breast cancer,especially for patients with advanced stages or breastconserving needs.However,due to the continuous stimulation of estrogen,ER?-positive breast cancer is very prone to chemotherapy resistance.It is extremely important to seek an integrated diagnosis and treatment method that can effectively kill tumors through reversing chemoresistance to solve this problem.We have constructed a multifunctional intelligent nanosystem(MONC-PPG-PTX/siNgBR),which can not only deliver genes and drugs to the target cells to therapy tumor but also load highefficiency photosensitizers CPDs for real-time imaging through PA imaging.It is a new treatment strategy for the personalized diagnosis and treatment of ER?-positive breast cancer with chemotherapy resistance.Objective: The MONs are loaded with CPDs as the core,PEI is coated on the MONCs to provide positive charge and lysosomal escape,and then PEI and PEG are connected through acid-degradable bonds to achieve long-term circulation and detachment in tumor region,GE11 peptides on the outermost layer to achieve the active targeting.Finally,loading si RNA and PTX at the same time.Testing their characteristics and gene/drug loading and release capabilities,and exploring its therapeutic effect and mechanism of chemoresistance ER? positive breast cancer.Comparison of elastography and photoacoustic intensities of chemoresistant and non-resistant ER?-positive breast cancer.Methods: Using micelle/precursor co-template assembly(M/P-CA)strategy to prepare MON-CPDs,and then PEI,PEG,and GE11 were modified respectively,and finally,PTX was loaded by solvent evaporation,and si RNA was loaded by electrostatic adsorption.Using a transmission electron microscope,thermogravimetric analyzer,nanoparticle size and zeta potential analyzer to detect the characterization of nanoparticles and the proportion of each component;use high performance liquid chromatography and micro-ultraviolet spectrophotometer to detect the loading and release of PTX and si RNA loaded on MONC-PPG nanosystem;the endocytosis and subcellular localization of nanosystem was observed with a confocal microscope and Bio TEM;Western Blot and q RT-PCR were used to determine the gene transfection ability of the nanoparticle;using CCK-8 and flow cytometry to detect the cell apoptosis with different treatments.In vivo,the photoacoustic imager and fluorescence imager of small animals are used to track the distribution of MONC-PPG and the tumor targeting ability;the MCF-7/PTX nude mouse model is constructed and the differences treatment effect of each group is recorded and analyzed by immunohistochemistry,WB,and H&E staining.Construct chemoresistant and non-chemoresistant ER?-positive breast cancer nude mice models and perform elastography and PA intensity detection.Result: The MONC-PPG-PTX/siNgBR nanosystem was successfully constructed.It has a mesoporous morphology,uniform size,and well-dispersed spherical structure.The drug loading capacity of PTX can reach 24.14%±1.87,and the loading capacity of si RNA can reach up to 33.3?g/mg,and both have p H and GSH-dependent release.The nanosystem have a good cell-killing effect,the cell killing of MONC-PPGPTX/siNgBR can reach 70.47%.In vivo experiments,MONC-PPG can specifically gather in the tumor and can perform photoacoustic and fluorescence imaging in vivo.In the treatment,MONC-PPG-PTX/siNgBR has excellent tumor treatment effects,which is significantly better than the single treatment group,fundamentally reversed the emergence of chemotherapy resistance and combined cytotoxic drugs to effectively kill tumors.The knockdown effect of Ng BR was 52.09%,and the tumor growth inhibition rate was as high as 70.22% in tumor-bearing nude mice.At the same time,the elastography and PA intensity of the drug-resistant group and the non-drug-resistant group showed significant differences.Conclusion: In this study,MONC-PPG-PTX/siNgBR nanoparticles were successfully prepared,which can specifically aggregate in the tumor region,have good biological safety and imaging capabilities,the gene knockdown ability is stable and efficient,and have excellent tumor suppression effects.Provide a new integrated personalized treatment strategy for chemoresistant ER? positive breast cancer diagnosis and treatment.