Effects Of MicroRNA-641 On The Growth,Apoptosis,Invasion And Migration Of Breast Cancer Cells By Regulating RRS1

Objective:Ribosomal biosynthesis regulatory protein 1(RRS1),as a novel ribosomal biosynthesis regulatory protein,is mainly involved in the maturation of 25 S r RNA and the assembly of 60 S ribosomal large subunits in ribosomal biosynthesis.Previous studies of our group have found that RRS1 is related to the proliferation,invasion and metastasis of breast cancer cells,but the molecular regulation mechanism of RRS1 in breast cancer remains unclear.By bioinformatics search,it was found that miRNA-641(miR-641)may have a targeted regulation relationship with RRS1.This study aimed to explore the targeted regulation relationship between miR-641 and RRS1,and to study its role in the proliferation,invasion and migration of breast cancer cells.Methods:(1)Real-time fluorescent quantitative PCR()was used to detect the m RNA expressions of miR-641 and RRS1 in MDA-MB-231,MDA-MB-453,BT549,MCF-7and HMEC in breast cancer cells and normal breast epithelial cells.The expression of RRS1 protein in breast cancer cells MDA-MB-231,MDA-MB-453,BT549,MCF-7 and normal breast epithelial cell line HMEC was detected by Western-blot assay.(2)Fresh breast cancer tissues and paracancerous tissues were collected and the m RNA expression levels of miR-641 and RRS1 in breast cancer tissues and paracancerous tissues were detected by RT-q PCR.The expression of RRS1 protein in breast cancer tissues and adjacent tissues was detected by Western-blot(3)Clinical case information of patients was collected,and the relationship between miR-641 and RRS1 expression levels and clinicopathological characteristics was analyzed.(4)BT549 cells and MCF-7 cells were selected for validation test.The cells were divided into blank group,miR-641 mimics NC group,miR-641 mimics group,miR-641 inhibitors NC group,miR-641 inhibitors group,and miR-641 inhibitors group.Mi R-641 inhibitors +si RNA NC group,miR-641inhibitors+ RRS1 si RNA group,and RRS1 si RNA group were transfected with miR-641 mimics,miR-641 inhibitors and RRS1 small interfering RNA,respectively.After transfection,the m RNA expression levels of miR-641 and RRS1 in transfected cells were detected by RT-q PCR and the protein expression levels of RRS1 in transfected cells were detected by Western-blot.(5)The binding site information of miR-641 and RRS1 was predicted by bioinformatics website,and the targeting relationship between miR-641 and RRS1 was detected by dual luciferase assay.(6)CCK8 assay and colony formation assay were used to detect the proliferation ability of transfected cells.The migration and invasion ability of transfected cells were detected by scratch test and Transwell test.Cell apoptosis were detected by flow cytometry after transfection.Results:(1)Compared with normal HMEC,the expression of miR-641 was lower in MDA-MB-231,MDA-MB-453,BT549 and MCF-7,and the expression of RRS1 was higher in breast cancer cells(P<0.05,P<0.01,P<0.001).(2)Compared with adjacent tissues,the expression of miR-641 was low in breast cancer tissues,and the expression of RRS1 was high(P<0.05).(3)Downregulation of miR-641 expression and up-regulation of RRS1 expression were closely related to the prognosis of breast cancer(P<0.05,P<0.01).(4)miR-641 can inhibit the expression of RRS1 in breast cancer cells.Mi R-641 was also verified to regulate RRS1(P<0.05,P<0.01).(5)Overexpression of miR-641 in breast cancer BT549 and MCF-7 cells can inhibit cell proliferation,invasion and migration,and promote cell apoptosis(P<0.05).Conclusions:In breast cancer cells,miR-641 can regulate RRS1 by targeting.miR-641 can inhibit the proliferation,migration and invasion ability of breast cancer cells,and promote breast cancer cell apoptosis.