Background Circular RNAs (circRNAs) have shown key regulatory roles in human malignancies. The working mechanism of circRNAs in hepatocellular carcinoma (HCC) remains to be elucidated. Methods Cell proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 5-ethynyl-20-deoxyuridine (EdU) assay, and colony formation assay. Xenograft tumor model was established to analyze the role of circ_MBNL3 on tumor growth in vivo. Results Circ_MBNL3 expression was notably down-regulated in HCC tissues and cell lines. Circ_MBNL3 overexpression suppressed the proliferation, migration, and invasion and induced the apoptosis of HCC cells. miR-873-5p directly targeted the 3’ untranslated region (3’UTR) of PHF2, and PHF2 was negatively regulated by miR-873-5p in HCC cells. miR-873-5p silencing-induced anti-tumor influences were largely reversed by the interference of PHF2 in HCC cells. Circ_MBNL3 restrained xenograft tumor growth in vivo. Conclusion Circ_MBNL3 restrained the proliferation, migration, and invasion and promoted the apoptosis of HCC cells depending on the regulation of miR-873-5p/PHF2 axis.

背景 环状 RNA (circRNA) 在人类恶性肿瘤中显示出关键的调节作用。circRNA在肝细胞癌（HCC）中的作用机制仍有待阐明。方法通过3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四唑(MTT)测定、5-乙炔基-20-脱氧尿苷(EdU)测定和集落形成测定分析细胞增殖。建立异种移植肿瘤模型，分析circ_MBNL3对体内肿瘤生长的作用。结果 Circ_MBNL3 表达在 HCC 组织和细胞系中显着下调。Circ_MBNL3过表达抑制HCC细胞的增殖、迁移和侵袭并诱导细胞凋亡。miR-873-5p直接靶向PHF2的3'非翻译区（3'UTR），并且PHF2在HCC细胞中受到miR-873-5p的负调节。HCC 细胞中 PHF2 的干扰很大程度上逆转了 miR-873-5p 沉默诱导的抗肿瘤影响。Circ_MBNL3 抑制体内异种移植肿瘤的生长。结论 Circ_MBNL3通过调控miR-873-5p/PHF2轴抑制HCC细胞的增殖、迁移和侵袭，促进细胞凋亡。