Breast cancer is the most frequently diagnosed and the leading cause of cancer-related deaths in women worldwide. However, the role of circSLC8A1 in breast cancer remains elusive. Herein, a cohort of 77 breast tumors and paired adjacent normal mammary tissues were collected. We demonstrated that circSLC8A1 was significantly down-regulated in breast cancer tissues and cell lines, of which expression was negatively correlated with clinical severity and dismal prognosis. Overexpression of circSLC8A1 suppressed cell proliferation, migration and invasion in vitro, and inhibited tumor growth in vivo. CircSLC8A1 directly targeted miR-671 to execute tumor suppressive activities via regulating PI3k/Akt signaling. Krüppel-like factor 16 (KLF16), a transcriptional activator of PTEN, was identified as a target of miR-671. Furthermore, circSLC8A1 could sponge miR-671 to suppress breast tumor growth via PTEN/PI3k/Akt signaling in vivo. In summary, circSLC8A1/miR-671 regulates breast cancer progression through PTEN/PI3k/Akt signaling, which may provide efficient therapeutic target for this devastating cancer.

乳腺癌是全世界女性最常被诊断出的癌症，也是癌症相关死亡的主要原因。然而，circSLC8A1 在乳腺癌中的作用仍然难以捉摸。在这里，收集了一组 77 个乳腺肿瘤和成对的相邻正常乳腺组织。我们证明了 circSLC8A1 在乳腺癌组织和细胞系中显着下调，其表达与临床严重程度和不良预后呈负相关。circSLC8A1的过表达在体外抑制细胞增殖、迁移和侵袭，在体内抑制肿瘤生长。CircSLC8A1 直接靶向 miR-671，通过调节 PI3k/Akt 信号传导来执行肿瘤抑制活动。Krüppel 样因子 16 (KLF16) 是 PTEN 的转录激活因子，被确定为 miR-671 的靶标。此外，circSLC8A1 可以海绵 miR-671 通过体内 PTEN/PI3k/Akt 信号传导抑制乳腺肿瘤的生长。综上所述，circSLC8A1/miR-671 通过 PTEN/PI3k/Akt 信号通路调节乳腺癌进展，这可能为这种毁灭性癌症提供有效的治疗靶点。