Circular RNA hsa_circ_0008039 promotes breast cancer cell proliferation and migration by regulating miR-432-5p/E2F3 axis

As the development of sequencing technology, more and more circular RNAs (circRNAs) are identified in human cancer tissues. Increasing evidences imply circRNAs are important regulators in tumor progression. Nevertheless, how circRNAs participate in breast cancer development and progression is not well understood. In the present study, we identified a novel circRNA hsa_circ_0008039 with upregulated expression level in breast cancer tissues. By functional experiments, we found that hsa_circ_0008039 depletion significantly suppressed the proliferation, arrested cell-cycle progression and reduced migration in breast cancer. Mechanistic investigations suggested that hsa_circ_0008039 served as a competing endogenous RNA (ceRNA) of miR-432-5p. Subsequently, E2F3 was identified as the functional target of miR-432-5p and overexpression of hsa_circ_0008039 elevated E2F3 expression in breast cancer. On the whole, our study indicated that hsa_circ_0008039 exerted oncogenic roles in breast cancer and suggested the hsa_circ_0008039/miR-432-5p/E2F3 axis might be a potential therapeutic target.