Study On The Mechanism Of Yiqixiao Compound Mediated Exosomal MiR-423-5p To Block Triple-negative Breast Cancer Resistance To Cisplatin

OBJECTIVETo study the function of exosomes?EXO?in transmitting drug resistance information between triple negative breast cancer cells and to study the reversal effect by Yiqi Formula and explore the mechanism in vivo and in vitro on human breast cancer DDP resistant cell that was establishes by drug-resistant cell exosomes method,which in order to provide experimental basis for clinical guidance in the treatment of triple negative breast cancer resistant use Yiqi formula.METHODSMDA-MB-231 cells resistant to DDP?231/DDP?were established.Exosomes were isolated from 231/DDP cells?DDP-EXO?and characterized by measuring the levels of protein markers,performing a nanoparticle tracking analysis and transmission electron microscopy.The MDA-MB-231,MCF-7 and SKBR-3 cell lines were treated with the isolated DDP-EXO and cell proliferation and cytotoxicity to DDP were evaluated using MTT assays and apoptosis analyses.Western blotting was used to examine P-gp expression.Additionally,a microarray was used to analyse micro RNA?micro RNA?expression profiles in MDA-MB-231 and 231/DDP exosomes.The effects on mi RNAs were determined using RT-PCR.Exosomal mi R-423-5p was extracted,and differential expression was verified.The MTT cell viability assay,flow cytometry,and Transwell and immunofluorescence assays were performed to determine if differential expression of mi R-423-5p sensitized cells to DDP in vitro.RESULTSUnder a transmission electron microscope,the isolated exosomes exhibited a round or oval shape with a diameter ranging between 40 and 100 nm.DDP/EXOs labelled with PKH67 were taken up by MDA-MB-231 cells.After an incubation with DDP/EXOs,the cell lines exhibited a higher IC₅₀ value for cisplatin,P-gp expression,migration and invasion capabilities and a lower apoptosis rate.Furthermore,60mi RNAs were significantly upregulated in exosomes derived from 231/DDP cells compared to exosomes from MDA-MB-231 cells.Notably,mi R-423-5p was the top differentially expressed mi RNAs in DDP-resistant exosomes compared with the corresponding sensitive exosomes.We chose mi R-423-5p,and the up-and downregulation of exosomal mi R-423-5p expression significantly affected DDP resistance.Yiqi Formula and cisplatin intervened DDP-EXO and MDA-MB-231co-cultured cells,MTT assay showed that the IC50 of cisplatin was significantly decreased?P<0.01?,flow cytometry,scratch test,Transwell,RT-q PCR.The results of quantitative PCR showed that the cell proliferation,invasion and metastasis ability and anti-apoptosis ability were decreased.In vivo results suggest that the drug resistance rate of nude mice transplated tumor model established by MDA-MB-231and DDP-EXO was 81.2%.Divided the loaded nude mice into four groups,and after 3week'administration,the volume of Yiqi Formula with cisplatin group was slower than that of other groups?P<0.05?;Yiqi Formula group and the combined group?Yiqi&Cisplatin?could decrease the expression of mi R-423-5p?AKT and increase the gene expression of PTEN?P<0.05?.ConclusionsExosomes from DDP-resistant TNBC cells?231/DDP?altered the sensitivity of other breast cancer cells to DDP in an exosomal mi R-423-5p-dependent manner.Our study helps to elucidate the molecular mechanism of DDP resistance in breast cancer.