Hsa_circ_0000851 promotes PDK1/p-AKT-mediated cell proliferation and migration by regulating miR-1183 in triple-negative breast cancer

Breast cancer (BC) is the most common cause of cancer-related mortality in women worldwide. Circular RNAs (circRNAs), a type of non-coding RNA, have garnered interest because of their unique looped structure. In recent years, circRNAs have been shown to be involved in various diseases, including carcinogenesis, and to serve as biomarkers for early risk assessment and survival prediction of different tumour types. This study aimed to identify a novel circRNA, hsa_circ_0000851, generated from the sixth intron of the oncogene TCF4, reported to be involved in BC pathogenesis. Our study showed that hsa_circ_0000851 was mainly located in the cytoplasm of BC cells and upregulated in BC cell lines and tissue samples. Higher hsa_circ_0000851 expression levels resulted in increased proliferation of BC cells both in vitro and in vivo, while treatment of BC cells with hsa_circ_0000851 siRNA decreased their proliferation. We found that hsa_circ_0000851 bound directly to miR-1183, accelerating the expression of its target gene PDK1, which facilities BC cell proliferation and migration through PDK1/p-AKT.