Inhibitory Effects Of MiR-26b-5p And Tamoxifen On Thyroid Papillary Carcinoma Cells

Background and objectiveThyroid cancer is the most common cancer in the endocrine system,and papillary thyroid carcinoma(PTC)is the most common.In recent years,the incidence of thyroid cancer has been increased rapidly.Female patients are about 3-4 times higher than men.Therefore,it is urgent to realize the development of thyroid papillary carcinoma and seek new diagnostic and therapeutic targets.miR-26b-5p,a gene regulatory factor,participates in the development of a variety of tumors(lung cancer,prostate cancer,etc.).A number of researches show that tamoxifen(TAM),the estrogen receptor inhibitor,play a certain role in breast cancer and other malignant tumors(such as liver cancer,pancreatic cancer and bile duct cancer).The aim of this study was to explore the effects of tamoxifen and miR-26b-5p on the biological behavior(proliferation,migration,and invasion)of thyroid papillary carcinoma BCPAP cells,and to explore the correlation between tamoxifen and miR-26b-5p.MethodsPathological tissue of 67 patients and clinical features were collected.Expression of miR-26b-5p in thyroid papillary carcinoma and paracarcinoma tissue was detected by using fluorescence quantitative PCR,and relationship between miR-26b-5p expression and the clinical features was analyzed using statistical methods.Then BCPAP was transfected with miR-26b-5p overexpression lentivirus and the capacity of its proliferation was detected by CCK8,and migration and invasion was detected by Transwell.Human thyroid papillary carcinoma BCPAP cells were treated with various concentrations of tamoxifen for 24 hours,CCK8 assay,Wound healing test and Transwell assay were used to detect the change of proliferation level,migration ability and invasion ability.Molecular mechanism was detected by Western blot and RT-PCR.Results1.The expression level of miR-26b-5p in thyroid papillary carcinoma tissues was significantly lower than that of paracarcinoma tissues(P<0.01)and correlated with lymph node metastasis(P<0.05).2.Overexpression of miR-26b-5p inhibited proliferation and metastasis of BCPAP.Western blot result showed the activity of GSK-3? was increased and the expression of P-catenin was depressed in miR-26b-5p overexpression BCPAP.3.CCK8 assay,wound healing test and Transwell assay showed that tamoxifen had induced a dose-dependent decrease in the proliferation,migration and invasion of human thyroid papillary carcinoma BCPAP cells.Furthermore,Western blot demonstrated that the tamoxifen decreased the expression of bcl-2 and C-myc in BAPAP cells,RT-PCR demonstrated that the tamoxifen increased the expression of miR-26b-5p.ConclusionThe expression level of miR-26b-5p in thyroid papillary carcinoma tissues was significantly decreased.miR-26b-5p depressed papillary thyroid carcinoma which maybe related with GSK-3?/?-catenin pathway,Tamoxifen can inhibit proliferation,migration and invasion of human thyroid papillary carcinoma BCPAP cells.We speculated that the inhibition of proliferation maybe related to down-regulation of bcl-2,C-myc and up-regulation of miR-26b-5p expression,which can provide new ideas with auxiliary clinical diagnosis and treatment for thyroid papillary carcinoma.