| Background and objective:Papillary thyroid carcinoma(PTC)is the most common endocrine malignancy in clinic,and its incidence has been increasing year by year in recent years.About 10%-15% of PTC patients often have distant metastasis and recurrence,which leads to poor effect of standard treatment and poor prognosis.Therefore,it is very necessary to study the molecular mechanism of the formation and development of PTC,which is of great significance to find new drugs for PTC treatment and improve the prognosis of PTC patients.MicroRNA(miRNA,miR)is a kind of noncoding RNA with about 22 nucleotides,which is involved in the basic physiological processes of cell differentiation,proliferation and metabolism.The abnormal expression of miRNA can regulate the expression of various oncogenes or tumor suppressor genes from the post transcriptional level,so as to regulate the occurrence and development of a variety of malignant tumors.MiR-206 has abnormal expression in a variety of cancers,such as breast cancer,liver cancer,gastric cancer,etc.,and its expression in papillary thyroid carcinoma is lower than that in normal tissues,but the specific biological function and mechanism of miR-206 in papillary thyroid carcinoma have not been clarified.When the receptor c-Met of hepatocyte growth factor(HGF)combined with HGF,c-Met can phosphorylate tyrosine residues and activate PI3K/Akt/mTOR pathway.The abnormally activated c-Met/AKT/mTOR pathway is closely related to the proliferation and migration of thyroid cancer,cervical cancer and other malignant cells.However,in PTC,whether miR-206 can inhibit cancer by inhibiting c-Met/AKT/mTOR signaling pathway has not yet been reported.The purpose of this study was to explore the effect of miR-206 on the proliferationand migration of papillary thyroid carcinoma K1 cells,verify that c-Met is the target gene of miR-206,and study the possible signal pathway related to its regulation,so as to screen new molecular intervention targets for clinical targeted treatment of papillary thyroid carcinoma.Methods:K1 cells in logarithmic growth phase of papillary thyroid carcinoma were divided into three groups,namely,blank group: no transfection;negative control group:transfection of miR-206 negative control sequence;experimental group: transfected with miR-206 mimic.After K1 cells were transfected with miR-206 mimic transiently,detection of miR-206 expression in each group of cells by reverse transcription quantitative PCR(RT-qPCR).The cell activity was detected by CCK-8 assay.The number of viable K1 cells was counted by the method of trypan blue staining.The migration ability of K1 cells was detected by Transwell migration chamber.Bioinformatics software was used to predict the target gene of miR-206.The targeting relationship between miR-206 and c-Met was verified by double luciferase reporter assay.The protein levels of c-Met,p-Met,AKT,p-AKT,mTOR and p-mTOR were detected by Western blot.Results:After K1 cells were transfected with miR-206 mimic transiently,the relative expression of miR-206 in the experimental group was significantly higher than that in blank group and the negative control group by RT-qPCR(P<0.05).The results of CCK-8 and trypan blue staining experiments showed that compared with blank group and negative control group,the proliferation ability of K1 cells in miR-206 mimic group was significantly inhibited(P<0.05).The results of Transwell experiment showed that the migration number of K1 cells in experimental group was lower than that in blank group and negative control group(P<0.05).Moreover,Western blot showed that theexpression levels of p-met,p-Akt and p-mTOR protein in the experimental group were significantly lower(P < 0.05).Conclusion:Up regulation of miR-206 can inhibit the proliferation and migration of papillary thyroid carcinoma K1 cells.The mechanism may be related to the inhibition of AKT/mTOR signaling pathway activation by miR-206 targeting c-Met. |
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