Circ_0108942 Regulates the Progression of Breast Cancer by Regulating the MiR-1178-3p/TMED3 Axis

Breast cancer (BC) has posed a fatal threat to women's lives and the search for new methods of diagnosis and treatment is an important way to break the bottleneck of high mortality in BC. Circular RNAs (circRNAs) have been confirmed to be aberrantly expressed in several types of cancers, and this study is intended to elucidate the role and mechanism of circ_0108942 in BC.

The levels of circ_0108942, microRNA-1178-3p (miR-1178-3p), and transmembrane p24 trafficking protein 3 (TMED3) were measured using real-time quantitative polymerase chain reaction (RT-qPCR) or western blot. Meanwhile, the cell proliferation, migration, invasion, angiopoiesis, and apoptosis were analyzed using 5-ethynyl-2'-deoxyuridine (EdU), transwell, tubule formation, and flow cytometry assays. Protein levels were determined by western blot. In addition, we used dual-luciferase reporter and RNA pull-down assays to identify the interplay between miR-1178-3p and circ_0108942 or TMED3. Lastly, the impact of circ_0108942 on the growth of BC tumors in vivo was analyzed by xenograft models.

Circ_0108942 and TMED3 were notably upregulated in BC, and the miR-1178-3p was downregulated. Functionally, silencing circ_0108942 suppressed cell proliferation, migration, invasion and promoted apoptosis in BC cells. In mechanism, circ_0108942 regulated TMED3 expression by sponging miR-1178-3p. Meanwhile, circ_0108942 knockdown also greatly constrained tumor growth in vivo.

Circ_0108942 boosted BC progression by regulating miR-1178-3p and thus upregulating TMED3.