The Molecular Mechanism Of LncRNA BCAR4 Involved In Breast Cancer Proliferation And Metastasis

Objective: To investigate the expression and significance of long non-coding RNA BCAR4 in human breast cancer cell lines and plasma,the effect of long non-coding RNA BCAR4 on the proliferation and invasion and migration of breast cancer and the possible molecular mechanism of the effect of long non-coding RNA BCAR4 on the proliferation and invasion and migration of breast cancer.Methods: 1.The expression of BCAR4 in 160 plasma samples(including80 untreated breast cancer patients and 80 healthy volunteers)was detected by qRT-PCR.2.The expression of BCAR4 in HBL-100 of breast cancer cell lines and human normal breast epithelial cells was detected by qRT-PCR.3.Breast cancer cells were transfected with si-bcar4 and the expression of BCAR4 was inhibited.4.Bioinformatics prediction software miRDB,starbase3.0v and TargetScan were used to predict the BCAR4-binding miRNA and its target gene,and the plasma expression of mir-644 a was detected in untreated breast cancer patients and healthy volunteers.5.The luciferase reporter assay examined therelationship between BCAR4 and miR-644 a and the relationship between miR-644 a and the target gene CCR7.6.The co-rotation experiment verified the hypothesis that whether BCAR4 acts as ceRNA to interact with mir-644 a,thereby affecting its target gene CCR7 to participate in the regulation of breast cancer proliferation and migration.Results:1.The level of BCAR4 in the plasma of breast cancer patients was significantly higher than that of healthy controls.In addition,the expression of BCAR4 was significantly correlated with the stage of breast cancer,specifically,the expression level in plasma of patients with advanced breast cancer was higher than that of patients with early breast cancer.In addition,the expression of BCAR4 in the plasma of the same patient after surgery was significantly lower than that before surgery.2.The expression of BCAR4 in 5 breast cancer cell lines was higher than that of hbl-100 cells.The expression levels of MDA-MB-231 and MCF-7in human breast cancer cells were the highest.3.After transfection with si-bcar4 and knockdown of the expression of BCAR4,the number of cells that survived and formed clones was significantly reduced,the rate of scratch healing was significantly reduced,the proliferation rate of breast cancer cells decreased,and the migration ability was reduced.4.The comprehensive analysis of software prediction showed that miR-644 a had a binding site with BCAR4,and the plasma level of miR-644 a in breast cancer patients was significantly lower than that in normal healthy controlpopulation.The expression level of miR-644 a in 5 breast cancer cell lines was also lower than that in HBL-100 cells,and the plasma results were consistent with the cell line results.5.The double luciferase reporter assay verified that BCAR4 could directly bind to miR-644 a,and miR-644 a could also directly bind to the target gene CCR7,and the binding sites of pair-to-pair-to-binding were identical.6.Co-rotating experiments verified that BCAR4 was involved in and promoted the proliferation and migration of breast cancer by competitively binding to mir-644 a and releasing more free CCR7.Conclution: In summary,this study showed that LncRNA BCAR4 was highly expressed in both plasma and breast cancer cells of breast cancer patients.As a oncogenic gene of breast cancer,BCAR4 can directly bind to mir-644 a and competitively bind to the binding site of miR-644 a and its target gene CCR7,thus increasing the number of free CCR7 that fails to bind to miR-644 a.That is,Long non-coding RNA BCAR4 participates in the proliferation and migration of breast cancer and promotes the occurrence and development of breast cancer through the axis of BCAR4--mir-644a--CCR7.Therefore,BCAR4 is closely related to breast cancer and has the potential to be a marker for early diagnosis and prognosis as well as a therapeutic target for breast cancer patients.