Preparation Of Esterase-responsive Gene Drug Carrier And Its Application In Tumor Treatment

Compared with traditional chemotherapy drugs,nucleic acid drugs can kill tumor cells more accurately,reducing damage to normal cells and tissues.However,simple genetic drugs are difficult to enter tumor cells accurately,and are susceptible to rapid nuclease cleavage and kidney / liver clearance.Therefore,advanced drug delivery vehicles are needed to facilitate their delivery.Due to the EPR effect,nanoparticles have been developed for tumor therapy.The stimulus-responsive nanoparticle system designed for the specific structure and physical and chemical properties of tumors has attracted more and more researchers' attention.Esterase is one of the overexpressed enzymes in tumor cells.Based on the above,we have designed a nucleic acid drug carrier(pDPD),which is mainly composed of cationic polymer polyethylaminoethyl methacrylate(pDEAEMA)and dexamethasone(DEX)as a hydrophobic layer and PEG.As a hydrophilic layer,it is finally prepared into amphiphilic micelles.The cationic polymer pDPD can carry the nucleic acid drug TRAIL through electrostatic action to form a pDPD / TRAIL conjugate.We also evaluated the biological safety and anti-tumor performance of the pDPD / TRAIL conjugate.main tasks as follows:(1)Synthesis of gene drug carrier: using diethylaminoethyl methacrylate as substrate,after bulk polymerization,it is quaternized with 4-methoxychlorobenzyl,and the methyl group is removed by anhydrous aluminum chloride catalytic solution,DCC reaction was used to mount dexamethasone,and finally PEG was wrapped in the outer layer.The structural changes were verified by infrared and nuclear magnetic.Finally,carrier micelles with a particle size of 35-60 nm and a molecular weight of about 18500 were synthesized,which was conducive to the EPR effect of drugs.The problem that the pure nucleic acid drug is difficult to reach the tumor cell is solved,and at the same time,the pDPD vector has the targeting ability for high concentration esterase in the tumor site.DEX can alleviate the inflammatory response brought about by tumor treatment and provide the effect of synergistic treatment with nucleic acid drugs.The PEG layer can enhance its long-term circulation performance and the hydrophilicity of the carrier.(2)Use agarose gel electrophoresis to test how tightly pDPD binds to the TRAIL gene and its responsiveness under the environment of esterase.At a pDPD / TRAIL nitrogen to phosphorus ratio of 5: 1 and above,pDPD can bind TRAIL nucleic acid drugs more tightly.In response to the defect that the cationic polymer carrier is difficult to release the drug after reaching the tumor site,pDPD / TRAIL has the ability to reverse charge.After entering the tumor cell,the esterase will hydrolyze the ester bond,and the potential will change from positive to negative,releasing TRAIL nucleic acid drug.(3)The cytotoxicity test and anti-tumor performance were tested.The pDPD / TRAIL conjugate can cause greater killing of cervical cancer cells.At a concentration of 500 ug / mL,the survival rate of HeLa cells is 22.89%,but not for normal cells L929 Shows significant cytotoxicity.At the same time,the anti-tumor performance test also proved that the pDPD / TRAIL conjugate has good anti-tumor performance and will not cause significant damage to the mouse body,and has good biological safety.