The Role Of MicroRNA-875-5p In The Targeted Regulation Of Foxf1 In The Progression Of Osteosarcoma And Its Related Mechanism

Research background:Osteosarcoma is an advanced malignant disease and is one of the most common primary malignant bone tumors,mainly in children and adolescents.Osteosarcoma most commonly occurs in the metaphysis of the long tubular bones of the extremities,with a very high mortality rate and a very poor prognosis.microRNA is a non-coding protein that can silence the translation of target mRNA by binding to the 3’untranslated region of the target protein mRNA,and numerous studies have shown that microRNAs play an important role in the progression of tumors,including osteosarcoma.The latest results show that microRNA-875-5p is abnormally expressed in a variety of tumors and has its regulatory role in tumor occurrence and development,but the role of microRNA-875-5p in osteosarcoma has not been reported.Objective:To detect the expression level of microRNA-875-5p in osteosarcoma cell lines,predict and verify its target in osteosarcoma,and explore the possible mechanism,so as to provide new clues and basis for targeted therapy of osteosarcoma.Research Methods:Firstly,by analyzing the GSE39058 data set in the GEO database,the expression trend of microRNA in osteosarcoma tissues in this data set was analyzed.Then,the top 25 down-regulated microRNAs in osteosarcoma patients’ tissue samples were listed,and the microRNAs that had been studied in osteosarcoma were excluded.Finally,microRNA-875-5p was selected as the microRNA to be studied.FOXF1 was predicted to be the target gene of microRNA-875-5p by bioinformatics using open microRNA databases(TargetScan,PicTarget and MicroCosm),and the relative expression of FOXF1 in osteosarcoma tissues was obtained by searching the GEPIA database.Realtime PCR(RT-qPCR)and western blot were used to determine the expression level of microRNA-875-5p and its target gene FOXF1 in osteosarcoma cell lines.U2OS cells were transfected with lentivirus to over-express microRNA-875-5p.Experimental group(microRNA-875-5p MIMICS)and control group(microRNA-875-5p NC)were constructed.The effects of transfection on the proliferation,migration,invasion,cell cycle and apoptosis of osteosarcoma cells were detected by cell functional experiment.The predicted target genes were verified by Western Blotting and dual luciferase reporter gene system.Results:The results of GEO database search and real-time PCR showed that the expression of microRNA-875-5p was significantly reduced in osteosarcoma tissues and osteosarcoma cell lines.In vitro experiments showed that overexpression of microRNA875-5p significantly inhibited osteosarcoma cells.At the same time,overexpression of microRNA-875-5p promoted the apoptosis and cell cycle changes of osteosarcoma cells.According to GEPIA database,FOXF1 was lowly expressed in osteosarcoma tissues.Subsequently,RT-qPCR and Western Blotting verified that FOXF1 was significantly down-regulated in osteosarcoma cell lines compared with normal osteoblast hFOB1.19.Dual luciferase assay confirmed that FOXF1 was the target gene of microRNA-875-5p,which further verified the bioinformatics prediction results.The expression of FOXF1 at protein level in U2OS cells transfected with microRNA-875-5p MIMICS was higher than that in the negative control(microRNA-875-5p NC)group by RT-qPCR and Western Blotting FOXF1 expression was positively correlated with microRNA-875-5p expression.Overall,this study demonstrated the role of microRNA-875-5p/FOXF1 regulatory axis in osteosarcoma,indicating that FOXF1 is a potential therapeutic target.Conclusion:In osteosarcoma cells,microRNA-875-5p targeting FOXF1 regulation can inhibit the proliferation,migration and invasion of osteosarcoma cells,and promote the apoptosis of osteosarcoma cells.