| Breast cancer is one of the most common malignant tumors with a high case-fatality rate among women.Compared with other subtypes,triple-negative breast cancer is more aggressive and lacks effective drug treatment targets,resulting in limited and ineffective treatment options for it.In recent years,light-mediated photodynamic therapy and photodynamic therapy Hyperthermia has attracted widespread attention due to its easy operation,low invasiveness and high specificity.However,the efficiency of single-mode treatment is limited by the hypoxic environment in the tumor,and the combined treatment requires multiple light sources for stimulation,which is complicated to operate and has large side effects.In order to achieve efficient and precise treatment of triple-negative breast cancer,covalent organic framework material(COF)was used as a carrier to adsorb the photosensitizer indole cyanine green(ICG)and the hypoxia-activating prodrug AQ4 N in COF.The-NH2 residue on the SURFACE of COF was used to modify HA on the surface of COF and finally obtained the HA-COF@ICG/AQ4 N drug carrier system.Differentiation cluster 44(CD44)as a receptor overexpressed on the surface of triple-negative breast cancer cells can be specifically targeted by hyaluronic acid.As the only near-infrared dye approved by the FDA for clinical application,ICG has both photodynamic and photothermal effects,but the free ICG solution is photo-unstable and prone to self-accumulation,resulting in low efficiency in photodynamic or photothermal therapy.AQ4 N is a novel bio-reductive prodrug that shows minimum toxicity in oxic cells,but strong antitumor activity in hypoxic cells by an enzymatic process via bio-reduction to its metabolite AQ4.Thus HA-COF@ICG/AQ4 N can actively target triple-negative breast cancer cells by binding to CD44 and excitation of loaded ICG under 808 nm near-infrared laser irradiation to produce photodynamic and photothermal combined effects.Photodynamic therapy exacerbates the hypoxic state of the tumor microenvironment,which in turn induces AQ4 N to be biologically reduced to anti-tumor drug AQ4,producing a synergistic anti-tumor effect.Finally,targeted and efficient therapy for triple-negative breast cancer will be achieved.The detailed research contents and results are as follows:(1)Synthesis and inhibition effect of COF@ICG.COF nanospheres with uniform particle size were synthesized by a one-step method,and ICG was adsorbed on COF by π-πstacking.Next,the drug loading capacity,encapsulated efficiency,and the ability of COF@ICG to release ICG in a p H-dependent manner were explored.It was found that when the concentration ratio of COF to ICG was no more than 1:1.4,the drug loading rate of ICG was 53.1% and the entrapment rate was more than 90%.And ICG exhibited higher release at p H 5.6,with a cumulative release of 72% in 20 h.The results recommended that the acidic conditions of the tumor microenvironment may trigger the release of ICG from the COF@ICG.The thermal properties of COF@ICG have been evaluated by digital NIR thermal imager.The results indicated that COF@ICG has better photothermal effect and photothermal stability than ICG.Furthermore,in vitro cytotoxicity of COF@ICG in normal cells and MDA-MB-231 cells were determined by MTT assay.Next,the photocytotoxicity of COF@ICG in the MDA-MB-231 cells was investigated by using MTT assay.The results showed that the survival rate of MDA-MB-231 cells in COF@ICG group decreased from90% to 50% after near-infrared light stimulation.(2)Construction of HA-COF@ICG/AQ4 N and the efficacy of synergistic antitumor.At first,HA-COF@ICG/AQ4 N was synthesized and characterized by several means such as TEM,UV/Vis,DLS measurement and Zeta potential analysis.Then cell viability under nearinfrared(NIR)light irradiation was evaluated using MTT assay and live/dead fluorescence staining.The MTT results showed that the survival rate of MDA-MB-231 cells was reduced to 23% after near-infrared illumination in the HA-COF@ICG/AQ4 N group,which was better than the inhibition effect of the COF@ICG group and the COF@ICG/AQ4 N group.ROS produced after near-infrared illumination stimulation in cells was detected using a specific reactive oxygen species assay kit.The results showed that both the COF@ICG/AQ4 N group and the HA-COF@ICG/AQ4 N group had ROS production after illumination,and the ROS content of the HA-COF@ICG/AQ4 N group was higher than that in the COF@ICG/AQ4 N group.The cell viability test kit was used to further study the changes in cell viability caused by light,and the results were consistent with the experimental results of MTT.The apoptosis was analyzed by flow cytometry,and the results indicated that compared with the blank group,the cells in the COF@ICG,COF@ICG/AQ4 N and HA-COF@ICG/AQ4 N groups all showed a trend of advanced apoptosis after light and the HA-COF@ICG/AQ4 N group had the most advanced apoptotic cells.The results of Western blot showed that near-infrared stimulation of ICG loaded experimental group would be conducive to the expression of HIF-1? protein in cells which indicated that Intracellular hypoxia is exacerbated.It can also be seen that the expression of CYP1A1 protein in the cell after near-infrared light in the COF@ICG/AQ4 N group also increased due to the biological reaction of AQ4 N.The results of cell migration experiments show that HA-COF@ICG/AQ4 N has a good inhibitory effect on the migration of MDA-MB-231 cells after near-infrared illumination.Finally,the effect of 3D tumor balls on the drug-loading system inhibiting the growth of solid tumors was studied,and the results showed that the HA-COF@ICG/AQ4 N group had a good inhibitory effect on the growth of tumor balls after light stimulation.In summary,this study constructed a hypoxia response HA-COF@ICG/AQ4 N nanodrug delivery system.The drug delivery system shows good anti-tumor effect and can inhibit the migration of tumor cells.It provides new ideas for the treatment of triple-negative breast cancer. |
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