MicroRNA-1298-5p Regulates Cervical Cancer Proliferation And Migration By Targeting SMC1A

BackgroundCervical cancer(CC)is one of the most common malignancies,ranking fourth in incidence and mortality among women.About 530,000 women are newly diagnosed with cervical cancer each year,and the patients are getting younger.Although the development of human papillomavirus(HPV)DNA testing and the standardized application of chemoradiotherapy have reduced the incidence and mortality of cervical cancer in recent years,the recurrence rate of cervical cancer is still up to 40%,and the mortality rate in developing countries is up to 87%.Therefore,it is of great significance to understand the pathogenesis of cervical cancer and search for potential diagnostic and prognostic indicators to improve the survival rate of cervical cancer patients.MicroRNAs(miRNAs)are a class of non-protein-coding small RNA molecules that regulate the expression of target genes at the post-transcriptional level.MiRNAs can bind to the 3'-untranslated regions(3'-UTR)of target mRNAs and regulate gene expression by either cutting the mRNA or inhibiting translation.Previous studies have shown that abnormal miRNA expression is associated with a variety of human malignancies,including cervical cancer.MiR-1298 is a new class of miRNA molecules discovered in recent years,and it is considered as a tumor inhibitor.It was reported to be down-regulated in bladder cancer,breast cancer,lung cancer,and gastric cancer,and has certain regulatory effects on the proliferation,migration,and apoptosis of tumor cells.In our previous study,we conducted miRNA chip sequencing on cervical cancer tissues and adjacent cervix tissues and found that miR-1298-5p was significantly down-regulated in cervical cancer tissues.However,the function and underlying mechanism of miR-1298-5p in cervical cancer are still unclear.As a member of the SMC superfamily,SMC1A is the core component of the cohesive protein complex required for sister chromatid cohesion.Its structure maintenance plays an important role in chromosome separation,cell cycle regulation,gene repair,and tumorigenesis.SMC1A is up-regulated or mutated in a variety of malignancies,and overexpression of SMC 1A is closely associated with poor prognosis in colorectal cancer patients.In this study,we detected the expression levels of miR-1298-5p and SMC1A genes in cervical cancer tissues.Besides,we explored the effect of miR-1298-5p on the proliferation and migration of cervical cancer cells.This study was mainly divided into two parts:in the first part,we detected the expression level of miR-1298-5p in cervical cancer tissues and cells;in the second part,we explored the effect of miR-1298-5p on the proliferation and migration of cervical cancer cells and its downstream mechanism.Part ? The expression of miR-1298-5p in cervical cancer tissues and cellsObjectiveTo detect the expression level of miR-1298-5p in cervical cancer tissues and cells,and evaluate the correlation between miR-1298-5p and clinical parameters.Methods1.A total of 32 pairs of cervical cancer specimens and adjacent cervix tissues were collected.The expression levels of miR-1298-5p in cervical cancer tissues and adjacent cervix tissues were detected by qRT-PCR.Then,we analyzed the correlation between miR-1298-5p and clinical parameters.2.The expression levels of miR-1298-5p in cervical cancer cell lines Hela and Siha,as well as normal cervical cell line Ectl/E6E7 were verified by qRT-PCR.Results1.Compared with adjacent cervix tissues,miR-1298-5p was significantly down-regulated in cervical cancer tissues(P<0.05).The expression level of miR-1298-5p was related to the FIGO grading and lymph node metastasis(P<0.05).2.Compared with normal cervical cell Ectl/E6E7,miR-1298-5p was significantly down-regulated in Hela and Siha(P<0.05).Part II MiR-1298-5p affects the proliferation and migration of cervical cancer cells by targeting SMC1AObjectiveTo analyze the effects of up-regulated miR-1298-5p on the proliferation and migration of Hela and Siha cells and preliminarily explore the possible molecular mechanism of miR-1298-5p in cervical cancer.Methods1.Hela and Siha cells were transfected with miR-1298-5p mimic and mimic NC,and the expression level of miR-1298-5p was detected by qRT-PCR.2.The CCK-8 assay and transwell chamber were used to detect the proliferation and migration activity of cervical cancer cells.3.Both miRanda and Targetscan were used to predict the target genes of miR-1298-5p.The SMC1A wild-type plasmid,SMC1A mutant plasmid or mock plasmid were co-transfected with miR-1298-5p mimic or mimic NC into Hela cell,respectively.Luciferase reporter kit was used to detect the luciferase activity.4.Hela and Siha cells were transfected with miR-1298-5p mimic and mimic NC,and the expression level of SMC1A was detected by qRT-PCR and Western blot.5.The expression level of SMC1A in cervical cancer and adjacent cervix tissues were detected by qRT-PCR.The Person correlation analysis was used to explore the correlation between SMC1A and miR-1298-5p.Results1.Compared with mimic NC group,miR-1298-5p was significantly up-regulated in Hela and Siha cells transfected with miR-1298-5p mimic(P<0.001).2.The proliferative and migratory abilities of Hela and Siha cells in the miR-1298-5p mimic group was significantly decreased compared with the mimic NC group(P<0.05).3.SMC1A was predicted as the target gene of miR-1298-5p.miR-1298-5p mimic reduced the luciferase activity of SMC1A-wt reporter gene to 42.6%but had no significant effect on SMC1 A-mut and mock plasmids(P<0.01).4.Compared with mimic NC group,the expression level of SMC1A in Hela and Siha cells transfected with miR-1298-5p mimic were significantly decreased in mRNA and protein levels(P<0.05).5.Compared with the adjacent cervix tissues,SMC1A was up-regulated in cervical cancer tissues.The expression level of SMC1A was negatively correlated with the expression level of miR-1298-5p(P<0.05).ConclusionMiR-1298-5p plays the role of tumor suppressor in cervical cancer tissues.MiR-1298-5p could inhibit the proliferation and migration of cervical cancer cells by targeting SMC1A.