Abstract

Background Circular RNAs (circRNAs) play a crucial role in the progression of malignant tumors such as breast cancer. Methods A circRNA microarray was used to detect key circRNAs in breast cancer. Expression of Circ72688 was verified by quantitative reverse transcription PCR (qRT-PCR) and fluorescence in situ hybridization (FISH) assay. Transwell assay and in vivo assay were conducted to prove the function of Circ72688. Exploring the downstream mechanism, dual-luciferase reporter assay, western blotting, and tissue microarray were performed. Results We sequenced and identified a circRNA, hsa-circ-0072688, also known as Circ72688. Our research found that Circ72688 enhanced tumor metastasis both in vivo and in vitro . Mechanistically, Circ72688 acted as a molecular sponge for hsa-miR-654-5p, thereby affecting the transcription of ORAI2. The expression levels of Circ72688 and ORAI2 were significantly higher in breast cancer tissues compared to adjacent normal tissues, and a notable positive correlation could be seen between them. Conclusions In summary, our study demonstrated the critical role of Circ72688 in breast cancer invasion and metastasis, and how Circ72688 partially regulated ORAI2 through hsa-miR-654-5p. Targeting Circ72688 might be a potential therapeutic strategy for breast cancer.