Circular RNAs (circRNA) have been reported as regulators involved in hepatocellular carcinoma (HCC), but their mechanism of activity remains unknown. This study performed quantitative reverse‐transcription polymerase chain reaction to determine if circNFATC3 was downregulated in 46 paired HCC tissues and cell lines. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide, apoptotic, and transwell assay proved that circNFATC3 can inhibit hepatoma cell proliferation, apoptosis, and migration/invasion in vitro. Mouse xenograft assay demonstrated that circNFATC3 suppressed tumor size and weight and reduced lung metastasis in vivo, and vice versa. The RNA‐seq results showed that NFATC3 itself was the most significantly differentially expressed gene when circNFATC3 was manipulated, and bioinformatics and luciferase reporter assays verified circNFATC3 regulated the expression of NFATC3 by interacting with the hsa‐miR‐548I. Additionally, it was also indicated that the level of NFATC3 was downregulated in HCC patients also and was significantly correlated with the staging and prognosis of HCC. Moreover, both circNFATC3 and NFATC3 were shown to inhibit the phosphorylation of JNK, c‐Jun, AKT, and mTOR signaling pathways. Overall, the circNFATC3 can sponge miR‐548I to protect NFATC3 itself, then it regulates hepatoma cell function via the JNK, c‐Jun, AKT, and mTOR signaling pathways, and the circNFATC3 can be a tumor‐repressor on HCC.

中文翻译：

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circNFATC3 海绵 miR-548I 作为 ceRNA 保护 NFATC3 本身并抑制肝细胞癌进展。

环状RNA（circRNA）已被报道为参与肝细胞癌（HCC）的调节剂，但其活性机制尚不清楚。本研究进行了定量逆转录聚合酶链反应，以确定 circNFATC3 在 46 对 HCC 组织和细胞系中是否下调。3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide、凋亡和transwell 实验证明circNFATC3 可以在体外抑制肝癌细胞增殖、凋亡和迁移/侵袭。小鼠异种移植试验表明，circNFATC3 在体内抑制肿瘤大小和重量并减少肺转移，反之亦然。RNA-seq结果表明，当circNFATC3被操纵时，NFATC3本身是差异表达最显着的基因，生物信息学和荧光素酶报告基因检测证实 circNFATC3 通过与 hsa-miR-548I 相互作用调节 NFATC3 的表达。此外，还表明 NFATC3 水平在 HCC 患者中也下调，并且与 HCC 的分期和预后显着相关。此外，circNFATC3 和 NFATC3 均显示出抑制 JNK、c-Jun、AKT 和 mTOR 信号通路的磷酸化。总体而言，circNFATC3 可以海绵 miR-548I 保护 NFATC3 本身，然后通过 JNK、c-Jun、AKT 和 mTOR 信号通路调节肝癌细胞功能，并且 circNFATC3 可以作为 HCC 的肿瘤抑制因子。还表明 NFATC3 水平在 HCC 患者中也下调，并且与 HCC 的分期和预后显着相关。此外，circNFATC3 和 NFATC3 均显示出抑制 JNK、c-Jun、AKT 和 mTOR 信号通路的磷酸化。总体而言，circNFATC3 可以海绵 miR-548I 保护 NFATC3 本身，然后通过 JNK、c-Jun、AKT 和 mTOR 信号通路调节肝癌细胞功能，并且 circNFATC3 可以作为 HCC 的肿瘤抑制因子。还表明 NFATC3 水平在 HCC 患者中也下调，并且与 HCC 的分期和预后显着相关。此外，circNFATC3 和 NFATC3 均显示出抑制 JNK、c-Jun、AKT 和 mTOR 信号通路的磷酸化。总体而言，circNFATC3 可以海绵 miR-548I 保护 NFATC3 本身，然后通过 JNK、c-Jun、AKT 和 mTOR 信号通路调节肝癌细胞功能，并且 circNFATC3 可以作为 HCC 的肿瘤抑制因子。