Construction Of A Bionic Nanoplatform Based On Photodynamic Therapy And PARP Inhibitor And Study Of Its Anti-Breast Cancer Effects

Triple-negative breast cancer(TNBC)is the most dangerous subtype of breast cancer,and there has been a lack of effective treatment strategies for a long time.Aiming at the mutation of the breast cancer susceptibility gene(BRCA1/2)carried by some TNBC cells,the poly(ADP-ribose)polymerase(PARP)inhibitors were developed by using the "synthetic lethal"effect.PARP inhibitors have shown a good therapeutic effect on BRCA mutant cancer types,and their molecular mechanism is to prevent the repair of DNA damage.Although PARP inhibitors can also kill cells without BRCA mutation,their sensitivity is greatly reduced.Combining PARP inhibitors with other therapies that can cause intracellular DNA damage may be an effective solution to this problem.Photodynamic therapy(PDT)is a relatively novel non-invasive treatment method for tumors,which has been used in clinical applications of various superficial tumors.Photosensitizers can generate singlet oxygen and other reactive oxygen species(ROS)under laser irradiation with a specific wavelength,thus directly damaging the DNA of tumor cells.However,due to the poor hydrophobicity and dispersibility of photosensitizers,the absorption and utilization rate of tumor cells is low,and its prognosis is not satisfactory.Using biocompatible polymer materials to nanocrystallize photosensitizers can effectively improve the above problems.At the same time,the bionic technology of tumor cell membrane developed in recent years has endowed nanoparticles with excellent characteristics such as immune escape,prolonged circulation time in vivo or targeted enrichment in tumors,which shows great potential and application prospect in the field of tumor immunotherapy.Based on this,a bionic nanoplatform 4T1Mem@PGA-Ce6/Ola(MPCO)was prepared by combining PDT with PARP inhibitor(Ola)and using highly biocompatible polyglutamic acid(PGA)as drug delivery carrier.PDT,chemotherapy and immunotherapy were integrated to treat breast cancer.The main research contents and results of this topic are as follows:1.Preparation and characterization of MPCO NPsThe photosensitizer chlorin e6(Ce6)was grafted onto PGA through a redox-sensitive cystamine bond to synthesize conjugated polymer PC,and Ola was encapsulated by film dispersion method to form PCO nanoparticles.MPCO was prepared by extracting mouse breast cancer 4T1 cell membrane coated nanoparticles and extruding with polycarbonate membrane.MPCO has good dispersibility and stability in water,and its morphology is spherical by transmission electron microscope.The particle size measured by dynamic light scattering was 202.43±1.50 nm,and the zeta potential was-17.5 ± 0.52 mV.The release behavior of MPCO was determined by dynamic membrane dialysis,and the results showed that MPCO could release drugs in response to the reduction environment of high glutathione in tumor cells.2.In vitro anti-tumor evaluation of MPCO NPs4T1 cells were selected to research the anti-tumor effect of MPCO NPs in vitro.Cell uptake studies showed that MPCO had higher internalization efficiency than free drugs.Intracellular lysosomal co-location and ROS detection proved that MPCO could produce ROS after laser irradiation to realize lysosomal escape.Cytotoxicity and other experiments showed that MPCO can exert strong cytotoxicity at low concentration under light conditions.yH2AX staining and cell cycle experiments proved that MPCO could prevent the self-repair of damaged DNA.Western Blot and cytokine experiments showed that the cyclic GMP-AMP synthase-stimulator of interferon genes pathway was activated.Calreticulin eversion,high mobility protein 1 release and adenosine triphosphate production verify that MPCO can induce immunogenic cancer cell death.The activation of bone marrow-derived dendritic cells proved the synergistic immune effect of MPCO which co-deliver Ce6 and Ola.3.In vivo anti-tumor evaluation of MPCO NPsThe anti-tumor effect in vivo was studied by 4T1 cells and female BALB/c mice.The results showed that the MPCO nanoplatform could be enriched in tumor tissue based on the homing effect of the tumor cell membrane,which effectively inhibited the development of a primary tumor and realized the strong activation of the immune system in vivo,inhibited the lung metastasis of the tumor,and contributed the production of long-term immune memory T lymphocytes.To sum up,an effective tumor treatment strategy was designed in this study,which integrated the advantages of PDT and PARP inhibitors.The designed MPCO nanoplatform showed a multi-level synergistic anti-tumor effect,which was of great significance to effectively prevent tumor growth and provided a reference for promoting the synergistic application of PDT,chemotherapy and immunotherapy.