Study On The Mechanism Of MiR-129-5p Targeting SOX4 To Inhibit The Growth Of Medulloblastoma

BACKGROUND: Medulloblastoma(MB)is the most common malignant tumor of the central nervous system in children,WHO grade IV,which is a primitive neuroectodermal tumor of the central nervous system.Often arising from the cerebellar vermis,the tumor is highly aggressive and can spread through the cerebrospinal fluid and metastasize to the spinal cord.Neurosurgical microsurgery and postoperative adjuvant radiotherapy and chemotherapy are the main clinical treatments,but they are still prone to recurrence after treatment and have a poor prognosis.Therefore,in order to find more effective treatment options,further understanding of the mechanism of MB development is needed to find new targets for therapy at the molecular level.More and more studies have shown that miRNAs play an important role in the occurrence and development of MB and have different effects on tumor proliferation,invasion,migration,and apoptosis.Hence,miRNAs may be used as a brand-new molecular therapeutic target of MB and become a new research hotspot.Objective: 1.Analyzing the expression profile of miRNAs in MB tissues and selecting significantly differentially expressed miRNAs;2.Verifying the effect of miR-129-5p on MB proliferation,invasion,migration and apoptosis and other biological behaviors;3.Predicting and analyzing the target genes of miR-129-5p and verifying its expression in tissues and cells.METHODS: 1.To consult NCBI GEO database,and analyze the expression of miRNAs in medulloblastoma tissues by bioinformatics methods,and select the miRNAs with significant expression differences,which are further verified by real-time PCR(qRT-PCR)technology;2.MB cell line Daoy was transfected with has-miR-129-5p mimic to up-regulate the expression of miR-129-5p,and the expression level of miR-129-5p after transfection of Daoy cells was verified by qRT-PCR technique,and then the effects of miR-129-5p expression changes on the proliferation,invasion,migration and apoptosis of Daoy cells were detected by CCK-8,transwell,cell scratch and flow cytometry,respectively;3.By bioinformatics methods,SOX4 gene was predicted and selected as the downstream target gene of miR-129-5p,and the differential expression of SOX4 gene in medulloblastoma tissues and normal brain tissues as well as Daoy cells was further verified by qRT-PCR technique and Western blot(WB).Results: 1.Through the analysis of the data in Pubmed GEO database,the differential miRNA named miR-129-5p,was finally determined and validated on tissues.It was found that the expressionof of miR-129-5p in medulloblastoma tissues was significantly lower than that in normal brain tissues,and the difference was statistically significant;2.After transfection with miR-129-5p,Daoy cell proliferation,migration and invasion were inhibited to varying degrees,and the level of apoptosis increased;3.SOX4 was predicted to be a potential target gene of miR-129-5p by bioinformatics.The expression of SOX4 gene in medulloblastoma was significantly higher than that in normal brain tissue,and the difference was statistically significant;and miR-129-5p down-regulated SOX4 expression level in Daoy cells.Conclusion: In this study,we found that miR-129-5p expression was decreased in MB,and after upregulating its expression,which inhibited MB cell proliferation,migration,invasion and induced MB cell apoptosis by negatively regulating SOX4.The regulatory mechanism provides a brand-new idea for exploring the molecular targeted therapeutic target of MB.