| BackgroundLung cancer is one of the fatal cancers worldwide,and over 60% of patients are lung adenocarcinoma(LUAD).Our clinical data demonstrated that DNA methylation of the promoter region of mi R-126-3p was upregulated,which led to the decreased expression of mi R-126-3p in 67 cases of lung adenocarcinoma tissues,implying that mi R-126-3p acted as a tumor suppressor.mi R-126-3p is a potential therapeutic strategy for treating LUAD,yet the electronegativity and easy degradation of mi RNA challenge further clinical application.In this study,MMP2 enzyme response peptides were designed to effectively bind to mi RNA and further modify nanoparticles with erythrocyte membranes,thereby improving cycle life,immune escape and biosafety.When the MMP2-responsive biomimetic nanoparticle remains absorbed by lung adenocarcinoma cells,a large number of MMP2 enzymes in lung adenocarcinoma cells will specifically recognize and cleat and decompose MMP2-responsive peptides,releasing mi R-126-3p mimics to achieve effective delivery of mi R-126-3p.To achieve the purpose of controlled release and effectively induce apoptosis of cancer cells.MethodsWe evaluated the expression of mi R-126-3p in 67 pairs of lung adenocarcinoma tissues and the corresponding adjacent non-tumorous tissues by Reverse transcription-quantitative polymerase chain reaction(RT-q PCR).The relation ship between the overall survival of lung adenocarcinoma patients and mi R-126-3p was4analyzed by the Cancer Genome Atlas cohort database(Oncolnc,http://www.oncolnc.org).We analyzed DNA methylation Methylation-specifc PCR(MSP)analysis.To determine whether ADAM9 is the direct target of mi R-126-3p,we performed the 3′-UTR luciferase reporter assay.The protein levels in the cells or tissues were evaluated with RT-q PCR and western blotting(WB)analysis.The MMP2 enzyme response peptide was combined with mi R-126-3p to form nanoparticle MAIN through positive and negative charge.Further,the anti-biogenic nanoparticle REMAIN was formed on the modified surface of erythrocyte membrane by ultrasonic extrusion.The characterization and in vitro performance of the nanoparticles were analyzed.The therapeutic effects of REMAIN were observed at the cellular and animal levels.The biodistribution of nanoparticles were monitored by in vivo tracking system.ResultsIn this study,at the epigenetic level,we found that the molecular mechanism of DNA hypermethylation of mi R-126-3p promoter negatively regulates self-expression in lung adenocarcinoma,and then targets ADAM9.Moreover,we describe the development of novel stealth and matrix metalloproteinase 2(MMP2)activated biomimetic nanoparticles,which are constructed using MMP2-responsive peptides to bind the mi R-126-3p(known as MAIN),and further camoufaged with red blood cell(RBC)membranes(hence named REMAIN).REMAIN was able to efectively transduce mi RNA into lung adenocarcinoma cells and release them via MMP2 responsiveness.Additionally,REMAIN possessed the advantages of the natural RBC membrane,including extended circulation time,lower toxicity,better biocompatibility,and immune escape.Moreover,in vitro and in vivo results demonstrated that REMAIN efectively induced apoptosis of lung adenocarcinoma cells and inhibited LUAD development and progression by targeting ADAM9.ConclusionThis study found that mi R-126-3p can effectively inhibit LUAD and target ADAM9 in LUAD.However,due to the physiological characteristics of mi R-126-3p,its further clinical application is limited.Therefore,a nanosystem based on rbcm coated with an MMP2-responsive peptide to deliver mi R-126-3p for the efficient treatment of lung adenocarcinoma has been developed.This novel biomimetic nanoparticle enables mi R-126-3p to effectively induce apoptosis of cancer cells and inhibit tumor growth and metastasis by targeting ADAM9.The novel stealthy and MMP2-activated biomimetic nanoparticles show great potential for mi RNA delivery,providing a theoretical basis for the treatment of lung adenocarcinoma. |
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