Regulatory effect and molecular mechanism of circ_0044556 targeting the miR-338-3p/BRD4 axis on the malignant biological behavior of triple negative breast cancer cells
10.11855/j.issn.0577-7402.0766.2025.0527
- VernacularTitle:circ_0044556靶向调控miR-338-3p/BRD4轴对三阴性乳腺癌细胞恶性生物学行为的调节作用及其分子机制
- Author:
Xing-Juan DONG
1
;
Ya-Li ZHANG
;
Wei XING
;
Ying-Ying ZHU
;
Yong-Li CHENG
;
Ping YU
Author Information
1. 河北省中医院普外科,河北 石家庄 050000
- Keywords:
circ_0044556;
miR-338-3p;
bromodomain-containing protein 4;
triple negative breast cancer;
proliferation;
migration;
invasion
- From:
Medical Journal of Chinese People's Liberation Army
2025;50(9):1146-1153
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the regulatory effect and molecular mechanism of circ_0044556 on the malignant biological behavior of triple negative breast cancer(TNBC)cells by targeting the miR-338-3p/bromodomain-containing protein 4(BRD4)axis.Methods The TargetScan online website was used to predict the binding sites of circ_0044556 with miR-338-3p and miR-338-3p with BRD4.Dual-luciferase reporter gene assays were performed to determine the relationship among circ_0044556,miR-338-3p,and BRD4 in MDA-MB-231 cells.Quantitative real-time PCR(qRT-PCR)and Western blotting were employed to detect the expression of circ_0044556,miR-338-3p,and BRD4 protein in human TNBC cell line MDA-MB-231 and human normal breast epithelial cells MCF-10A.MDA-MB-231 cells were divided into NC group,si-NC group(transfected with si-NC),si-circ_0044556 group(transfected with si-circ_0044556),si-circ_0044556+inhibitor NC group(transfected with si-circ_0044556 and inhibitor NC),and si-circ_0044556+miR-338-3p inhibitor group(transfected with si-circ_0044556 andmiR-338-3p inhibitor).qRT-PCR was applied to detect the expression of circ_0044556 and miR-338-3p;Western blotting was used to detect the expression of BRD4,E-cadherin,N-cadherin and Vimentin;the CCK-8 assay was applied to detect cell proliferation;flow cytometry was applied to detect cell apoptosis;and Transwell assays were used to detect cell invasion and migration.Thirty nude mice were randomly divided into NC group(tail vein injection of normal saline),si-NC group(tail vein injection of LV-NC),si-circ_0044556 group(tail vein injection of LV-circ_0044556),si-circ_0044556+inhibitor NC group(tail vein injection of LV-circ_0044556 and antiagomir NC),and si-circ_0044556+miR-338-3p inhibitor group(tail vein injection of LV-circ_0044556 and antiagomir miR-338-3p),with 6 mice per group.A xenograft tumor model was constructed by subcutaneous injection of MDA-MB-231 cells into nude mice,and tumor volume and weight were measured.Results TargetScan prediction results showed that the downstream miRNA of circ_0044556 was miR-338-3p,and the downstream target gene of miR-338-3p might be BRD4.Compared with transfecting mimic NC,transfection with miR-338-3p mimic significantly reduced the luciferase activities of WT-circ_0044556(0.34±0.03 vs.1.00±0.15,P<0.05)and WT-BRD4(0.41±0.05 vs.1.05±0.13,P<0.05)in MDA-MB-231 cells.Compared with MCF-10A cells,the expression levels of circ_0044556 and BRD4 protein in MDA-MB-231 cells were significantly increased,while the expression level of miR-338-3p was significantly decreased(P<0.05).Compared with NC group and si-NC group,the expression levels of circ_0044556,the protein expression levels of BRD4,N-cadherin,and Vimentin,and the OD450 value in MDA-MB-231 cells of si-circ_0044556 group and si-circ_0044556+inhibitor NC group were significantly decreased(P<0.05),the number of migrated and invaded cells was significantly reduced(P<0.05),and the expression level of miR-338-3p,the protein expression level of E-cadherin,and the cell apoptosis rate in MDA-MB-231 cells were significantly increased(P<0.05);downregulation of miR-338-3p rescued the inhibitory effect of circ_0044556 knockdown on invasion,migration,and proliferation of MDA-MB-231 cells.Compared with NC group and si-NC group,the tumor volume and weight in si-circ_0044556 group and si-circ_0044556+inhibitor NC group were significantly decreased(P<0.05);compared with si-circ_0044556 group and si-circ_0044556+inhibitor NC group,the tumor volume and weight in si-circ_0044556+miR-338-3p inhibitor group were significantly increased(P<0.05).Conclusion circ_0044556 may promote the malignant biological behaviors of TNBC cells through the miR-338-3p/BRD4 axis.
