The Role Of MiR-135a-3p In Proliferation And Migration Of Nonfunctional Pituitary Adenoma

Background:Pituitary adenoma PA is a common tumor of the central nervous system.For endocrine function,pituitary adenoma can be divided into functional pituitary adenoma and nonfunctional pituitary adenoma.Epidemiological studies have shown that nonfunctional pituitary adenomas account for about half of all PA.Most non-functional pituitary adenomas to benign biological characteristics and the surrounding tissue structure without affect infiltration,a small number of NFPA towards biological characteristics of malignant tumor,show the tumor to the saddle,the saddle branch into the bottom of the saddle invasive growth,invasion of cavernous sinus,package Rao Geng inside arteries,destroy the saddle bottom to the top of sphenoid sinus wall bone,intrusion in sphenoid sinus,etc.,It was called invasive pituitary adenoma(IPA).Due to the aggressive pituitary tumor growth characteristics,total surgical resection is difficult,and the postoperative recurrence rate is high.The aggressiveness of NFPA is the key factor affecting the surgical effect,and it is highly correlated with the prognosis of patients.Micro RNAs are short segment(19 to 25 nucleotides,miRNAs)non-coding RNAs that play key roles in regulating many biological processes,including development,differentiation,and tumor migration and invasion.Tumor cells exhibited an aberrant mir-135a-3p expression profile compared to normal cells,suggesting that mir-135a-3p may play an important role in tumor formation and progression.Studies have found that the expression of miR-135a-3p is unbalanced in various tumor tissues or cells of the nervous system,which will affect the proliferation,invasion and migration ability of tumor cells.However,the expression of miR-135a-3p in PA tissues and the regulatory effect of miR-135a-3p on the biological function of PA cells have not been elucidated in the existing literature.Objective:The differences in the expression of miR-135a-3p in invasive and non-invasive NFPA were determined by detecting tumor tissue specimens,and the effects of miR-135a-3p on the proliferation and invasive biological behavior of NFPA were further investigated by cell experiments,so as to find downstream targets and explore its potential mechanism of action.Methods:Fluorescence quantitative PCR was used to detect the relative expression levels of mir-135a-3p in 50 NFPA tissue samples(25 invasive and 25 noninvasive tissues)from patients undergoing pituitary tumor surgery at the neurosurgery Affiliated Hospital of Qingdao University from June 2018 to March 2020.Normal rat pituitary tumor cell lines were cultured and randomly divided into experimental group and negative control group.The cells were transfected with miR-135a-3p NC and miR-135a-3p inhibitor,respectively.The expression of miR-135a-3p was detected by fluorescence quantitative PCR.The proliferative ability of pituitary tumor cells was detected by CCK8 method.Transwell test was used to detect the migration ability of pituitary tumor cells.Bioinformatics databases were searched for downstream targets of miR-135a-3p.The interaction between miRNA and target genes was verified by dual luciferase report assay,and the expression of target miRNA genes was detected by Western Blot.Results:The results showed that the expression level of miR-135a-3p in the invasive NFPA samples was significantly higher than that in the non-invasive NFPA group.The cell proliferation of tumor cell lines transfected with miR-135a-3p inhibitor by pituitary gland was lower than that of negative control group.The cell migration ability of pituitary tumor cells in miR-135a-3p inhibitor group was decreased compared with the negative control group.The downstream target gene of miR-135a-3p was predicted: BAK1;Knocking down miR-135a-3p level promoted BAK1 expression.Conclusion:The expression of miR-135a-3p was significantly higher in invasive NFPA than in non-invasive NFPA.Knockdown of miR-135a-3p level in MMQ and GH3 tumor cells can significantly inhibit the proliferation and migration ability of pituitary tumor cells.BAK1 is a downstream target gene of miR-135a-3p.The knockdown of miR-135a-3p level can promote the expression of BAK1 in MMQ and GH3 cells.Further studies need to reveal the relationship between BAK1 and the proliferation and migration ability of pituitary adenoma.