MiRNA-145-5p Restrains Malignant Behaviors of Breast Cancer Cells Via Downregulating H2AFX Expression

Background: Breast cancer is a prevalent tumor with high aggressiveness among female populations. MiRNA-145-5pplays an important role in multiple cancers.Materials and Methods: qRT-PCR detected miRNA-145-5p and histone protein family member X (H2AFX) mRNAexpression in breast cancer cells, and western blot determined the protein expression of H2AFX. After predicting the target genes via the bioinformatics methods, the targeting relationship between miRNA-145-5p and H2AFX was verified by dualluciferase, RIP, and RNA pull-down assays. The relationship between H2AFX and clinical indexes was also analyzed. Furthermore, the effects of miRNA-145-5p/H2AFX regulatory axis on breast cancer cell progression were determined by colony formation, wound healing, CCK-8, and Transwell assays.Results: The results suggested that miRNA-145-5p was markedly lowly-expressed in breast cancer tissue and cells,while H2AFX was upregulated, which had a positive correlation with T stages of breast cancer. Besides, overexpressedmiRNA-145-5p was found to remarkably suppress progression of breast cancer cells. As bioinformatic analysis predictedthat H2AFX was the potential target of miRNA-145-5p, the dual-luciferase assay was conducted, which demonstratedthat miRNA-145-5p negatively regulated the expression of H2AFX by targeting its 3’-UTR. The rescue experimentdemonstrated that overexpression of miRNA-145-5p could offset the promotion effects of oe-H2AFX on malignantprogression.Objective: Our study is aimed at exploring how miRNA-145-5p functions in breast cancer cells.Conclusion: Our findings confirmed that miRNA-145-5p hindered malignant progression of breast cancer by negativelyregulating H2AFX. MiRNA-145-5p/H2AFX axis may be a novel therapeutic target for breast cancer.