Hepatocellular Carcinoma (HCC) is the main histological subtype of liver malignancy with poor prognosis. A growing body of evidence showed that Circular RNAs (circRNAs) are related to HCC tumorigenesis and progression. In this study, we investigated the function and regulation of circ-0038718 in HCC. We found that circ-0038718 was frequently elevated in HCC specimens and cell lines. High expression levels of circ-0038718 were correlated with unfavorable prognosis in HCC patients. Furthermore, we demonstrated that knockdown of circ-0038718 attenuated HCC cell proliferation and metastatic abilities, while overexpression of circ-0038718 resulted the converse effect. Silencing circ-0038717 inhibited HCC xenograft tumor development in vivo. Mechanistically, circ-0038718 acted as the sponge of tumor-suppressive miR-139-3p to regulate HCC progression. Rescue experiments suggested the oncogenic activity of circ-0038718 was partially exerted via modulating miR-139-3p expression. Inhibition of miR-139-3p abrogated the regulatory effect of circ-0038718 in HCC cells. In summary, our results unveiled that circ-0038718 could serve as an crucial regulator of HCC progression and provide a potential therapeutic target for HCC treatment.

肝细胞癌（HCC）是肝恶性肿瘤的主要组织学亚型，预后较差。越来越多的证据表明，环形RNA（circRNA）与肝癌的发生和发展有关。在这项研究中，我们研究了circ-0038718在肝癌中的功能和调控。我们发现circ-0038718在HCC标本和细胞系中经常升高。circ-0038718的高表达水平与HCC患者的不良预后相关。此外，我们证明敲除circ-0038718减弱了HCC细胞的增殖和转移能力，而circ-0038718的过表达导致了相反的作用。沉默circ-0038717在体内抑制HCC异种移植肿瘤的发展。从机理上讲，circ-0038718充当抑制肿瘤的miR-139-3p的海绵，以调节HCC进程。救援实验表明，circ-0038718的致癌活性是通过调节miR-139-3p表达而部分发挥的。对miR-139-3p的抑制废除了circ-0038718在HCC细胞中的调节作用。总之，我们的研究结果表明，circ-0038718可以作为HCC进展的关键调节剂，并为HCC治疗提供潜在的治疗靶标。