Correlation Between Overexpression Of MiRNA-21-3p/34a-3p And Glioma

Background:Glioblastoma(GBM)is the most common malignant brain tumor with the highest degree of malignancy and the worst prognosis in the central nervous system.At present,the main treatments include maximal surgical resection of tumor tissue combined with postoperative radiotherapy and temozolomide chemotherapy.However,even after receiving the optimal treatment,the median survival time is only 14.6 months.MicroRNAs(miRNAs),a class of small molecular non-coding RNA,involved in post-transcriptional gene regulation.It consists of a guide chain(miRNA)and a passenger chain(miRNA*).A great deal of research has reported that miRNAs plays an important role in cell differentiation,proliferation,apoptosis and other biological processes.In the past,it was thought that only miRNA,as a leading chain,was selectively loaded into the Argonaute(AGO)protein and then further assembled into the miRNA-induced silencing complex(miRISC),which binds to the target gene mRNA to play a related regulatory role.The passenger chain is degraded by helicase because of its low expression level.However,miRNA*has been found to play an important role as a functional chain in recent years.Among them,miR-21-3p and miR-34a-3p is the most widely studied.However,the correlation between miR-21-3p and miR-34a-3p expression and glioma invasion phenotype has not been explored.Objective:To investigate the relationship between the expression levels of miR-21-3p and miR-34a-3p and the glioma invasion phenotype.Methods:The expression of miR-21-3p and miR-34a-3p in glioma cells(A 172,U373,SNB19)was detected by qRT-PCR.Then a glioma cell line with low expression of miR-21-3p and miR-34a-3p was selected and transfected into NC mimics,miR-21-3p mimics,miR-34a-3p mimics for 48 h.qRT-PCR was used to detect the expression level of miR-21-3p and miR-34a-3p in glioma cells after transfection respectively to ensure the high expression level.After that,the effects of NC mimics,miR-21-3p mimics and miR-34a-3p mimics on proliferation,invasion and migration of A172 cells were observed by CCK-8 cell proliferation test,Transwell invasion assay and Wound healing assay,respectively.In addition,the expression of AG02 protein in NC mimics group,miR-21-3p mimics group and miR-34a-3p mimics group was detected by Western blot.Result:The results of qRT-PCR showed that the expression level of miR-21-3p in A172 cell line was lower than that in U373,SNB19(p<0.001).The expression level of miR-34a-3p in A172 cell line was lower than that in U373,SNB19(p<0.001).After consideration,we select A172 cell line for next-step transfection experiment.We used qRT-PCR to detect the expression of miR-21-3p/miR-34a-3p in the transformed A172 cell line again.The results showed that the expression of miR-21-3p in miR-21-3p mimics group was significantly higher than that in NC mimics group<0.001),and the expression level of miR-34a-3p in miR-34a-3p mimics group was also significantly higher than that in NC mimics group.(p<0.001).The results of CCK-8 assay showed that the cell activity of miR-21-3p mimics group was significantly higher than that of NC mimics group(p<0.05).The cell activity of miR-34a-3p mimics group was significantly higher than that of NC mimics group(p<0 05),indicating the overexpression of miR-21-3p/miR-34a-3p significantly increased the proliferation of glioma cell line A172.Transwell invasion assay showed that the number of transmembrane cells per trans-field in Transwell chamber was significantly different from that in NC mimics group in A172 glioma cells transfected with miR-21-3p mimics/miR-34a-3p mimics(p<0.001),indicating that overexpression of miR-21-3p/miR-34a-3p promotes the invasion of glioma cells.At the same conditions and time points,the results of Wound healing assay showed that the number of cell migration in A172 glioma cells transfected with miR-21-3p mimics/miR-34a-3p mimics was significantly higher than that in the NC mimics group(p<0.001),indicateing that overexpression of miR-21-3p and miR-34a-3p promotes the migration of glioma cells.These results suggested that the expression of miR-21-3p,miR-34a-3p was positively correlated with the proliferation,invasion and migration ability of A172 glioma cells.In addition,Western blot results showed that the expression levels of AGO 2 protein were down-regulated in the miR-21-3p mimics group and the miR-34a-3p mimics group compared with the NC mimics group.Conclusion:The high expression of miR-21-3p,miR-34a-3p can promote the invasion,migration and proliferation of glioma cell line A172,suggesting that it may play an important role in the invasion and metastasis of glioma cells.In addition,the expression level of AGO-2 protein was down-regulated after overexpression of miR-21-3p,miR-34a-3p,suggesting that miR-21-3p,miR-34a-3p may play a carcinogenic role by binding to AGO-2 protein and then affecting the corresponding target gene mRNA.