Circ-ABCA1 promotes breast cancer stem cell-mediated malignant progression by modulating miR-33a-5p/EIF4A3 axis.

To explore new circRNA and underlying mechanisms through which they regulate breast cancer progression. In this study, high-throughput sequencing were used to reveal the different expression of circRNA among breast cancer tissues and para-carcinoma tissue. Fluorescence in situ hybridization (FISH) were used to analysis the expression and subcellular localization of circ-ABCA1 in both breast cancer tissues and cells line. The regulatory mechanism and targets were then investigated utilizing bioinformatics analyses, luciferase reporter assay, transwell migration, CCK8, and EdU analysis. The in vivo experiments was used to elucidate the roles of circ-ABCA1 in breast cancer tumor metastasis and growth. The result show that circ-ABCA1 expression was increased in both breast cancer tissues and cells line. Downregulation circ-ABCA1 inhibit cells proliferation and tumor growth. Luciferase report analysis confirmed both miR-33a-5p and EIF4A3 were the downstream target of circ-ABCA1. Overexpression of EIF4A3 or inhibit miR-33a-5p restored breast cancer cells proliferaion, migration and breast cancer cells stemness ability after silence circ-ABCA1. Overexpression of EIF4A3 restored breast cancer proliferaion, migration and breast cancer cells stemness ability after expression miR-33a-5p. Taken together, our study confirmed that circ-ABCA1 promotes breast cancer stem cell-mediated malignant progression by modulating miR-33a-5p/EIF4A3 axis.