Construction Of Delivery System For Celastrol Loaded Magnetic Fe₃O₄/Fe₂O₃ Heterogeneous Nanorods And Its Effect On SMMC-7721 Cell Apoptosis

The excellent antitumor activity of celastrol made celastrol expected to be a more effective antitumor drug than traditional chemotherapeutic drugs such as cisplatin and paclitaxel.But the poor water solubility,low bioavailability and other shortcomings hinder its clinical application.In recent years,the use of magnetic iron oxide nanomaterials as carriers to achieved accurate delivery of anti-tumor drugs has become one of the research hotspots.The excellent cell/tissue penetration effect brought by the rod-shaped morphology of nanomaterials had also received widespread attention in the scientific research field.Iron oxide heterogeneous nanorods were used as a drug loading system of celastrol.It could realize the high loading and slow release,enhance the therapeutic effect and reduce side effects of the celastrol.It also opened up a novel path for the clinical application of insoluble natural Chinese herbal extracts,and provided a new idea for the treatment and prevention of liver cancer.The main research processes and conclusions were as follows.?1?Preparation of magnetic Fe₃O₄/Fe₂O₃ heterogeneous nanorods.?-FeOOH nanorods were prepared by hydrothermal method with inorganic salts as the basic raw materials.The length and diameter of?-FeOOH nanorods increased with the increase of titration rate and solution concentration.The increase of reaction pressure could increase the length of the material but reduce the diameter.The?-FeOOH nanorods of the ideal size could be obtained with 0.1 M FeCl₃ and 0.1 M KOH,30 mL·h^-1 of titration speed and medium pressure.The length and the diameter of the?-FeOOH nanorods was 170nm and 40 nm,respectively.Fe₃O₄/Fe₂O₃ heterogeneous nanorods were prepared by rapid combustion method with the?-FeOOH nanorods as precursor.Fe₃O₄/Fe₂O₃heterogeneous nanorods with strong magnetic property could be obtained with the 30 mL of absolute ethanol and the calcination temperature of 300 ^oC.The strongest magnetic property of the Fe₃O₄/Fe₂O₃ heterogeneous nanorods was 33.2 emu·g^-1,the average length was 140 nm,and the average diameter was 20 nm.?2?Construction and evaluation of magnetic Fe₃O₄/Fe₂O₃/CA-PEG-celastrol nanocomposites.The citric acid and PEG were used to modify the Fe₃O₄/Fe₂O₃ heterogeneous nanorods by EDC/NHS reaction to improve their dispersion characteristics in aqueous solution.The loading conditions of the celastrol were explored,and drug release experiments were carried out.The results showed that the hydrodynamic size range of the Fe₃O₄/Fe₂O₃/CA-PEG-CST was 250-500 nm,the surface potential was-15mV,and the saturation magnetic magnetization was 23 emu·g^-1.Besides,the drug loading and release effect of the Fe₃O₄/Fe₂O₃/CA-PEG was evaluated,and it had a higher drug loading capacity.The Fe₃O₄/Fe₂O₃/CA-PEG-CST had the characteristics of a slow-release and pH-sensitive ability.?3?The apoptosis mechanism of Fe₃O₄/Fe₂O₃/CA-PEG-CST to SMMC-7721.Prussian staining and electrochemical experiments proved that Fe₃O₄/Fe₂O₃/CA-PEG-CST could be ingested by liver cancer cells SMMC-7721,which could significantly increase the ability of cells to ingest carriers in the presence of a magnetic field.MTT experiments showed that Fe₃O₄/Fe₂O₃ and Fe₃O₄/Fe₂O₃/CA-PEG have no toxic effect on liver cancer cells and normal liver cells L-02,which proved the good cell compatibility of the carrier.The magnetic field significantly promoted the inhibition of Fe₃O₄/Fe₂O₃/CA-PEG-CST on liver cancer cells.Celastrol,and Fe₃O₄/Fe₂O₃/CA-PEG-CST could inhibit the migration of hepatocellular carcinoma cells,increased the expression of ROS in hepatocellular carcinoma cells,and promoted apoptosis.Apoptosis-related proteins?p53,Bax,Bcl-2?,and hypoxia-inducible factor?HIF-1??were detected by western blotting,and related pathways were verified by using NAC reactive oxygen scavengers.Fe₃O₄/Fe₂O₃ and celastrol promote intracellular ROS expression,which in turn increased the accumulation of hypoxia-inducible factor HIF-1?which competed with p53 bound to MDM2.The accumulation of p53 was promoted,and then activated the p53-induced apoptotic pathway.Hence,the expression of Bax and caspase-3 were increased,and the expression of Bcl-2 was decreased.