circCORO1C promotes the proliferation and metastasis of hepatocellular carcinoma by enhancing the expression of PD-L1 through NF-κB pathway.

Circular RNA (circRNA) affects the occurrence and development of human cancers, but the specific mechanism of hepatocellular carcinoma (HCC) has not yet been fully understood. CircRNAs were determined by human circRNA array analysis and quantitative reverse transcription polymerase chain reaction (qRT-PCR). Cell viability, migration, invasion, and other indicators were used for cell function analysis. Knockdown and overexpression techniques were used to explore the mechanism of circCORO1C in the occurrence and development of HCC by RNA sequencing, qRT-PCR, western blot, and other methods. Among the thousands of circRNAs, 1238 circRNAs were significantly changed. As for the top 10 upregulated circRNAs, the expression of circRNAs, hsa_circ_0036412, hsa_circ_0036411, hsa_circ_0028071, hsa_circ_0036409, hsa_circ_0000437, hsa_circ_0021427, hsa_circ_0097182, hsa_circ_0028067, hsa_circ_0006852, and hsa_circ_0003620 were significantly increased. In regard to the top 10 downregulated circRNAs, the expression of hsa_circ_0123629, hsa_circ_0096121, hsa_circ_0038932, hsa-circRNA3310-44, hsa_circ_0045746, hsa_circ_0016836, hsa-circRNA10899-9, hsa_circ_0050116, hsa_circ_0035543, and hsa_circ_0092118 decreased significantly. About these circRNAs, the downregulation of hsa_circ_0006852 (circCORO1C) can inhibit the tumorigenesis of HCC cells in vivo and in vitro, and the overexpression of circCORO1C can enhance the proliferation and metastasis ability of HCC cells. Mechanistically, circCORO1C activated the NF-κB signaling pathway, increased P65 phosphorylation and upregulation of c-Myc and COX-2, leading to increased PD-L1 expression. CircCORO1C upregulates c-Myc and COX-2 through NF-κB signaling pathway, leading to the upregulation of PD-L1, which jointly promotes the development of HCC, suggesting that circCORO1C is a promising biomarker and therapeutic target for HCC.

Wu F ，Sun G ，Zheng W ，Tang W ，Cheng Y ，Wu L ，Li X ，Tao J ，Ma S ，Cao H ... -  《-》

Circular RNA hsa_circ_0005239 contributes to hepatocellular carcinoma cell migration, invasion, and angiogenesis by targeting the miR-34a-5p/PD-L1 axis.

Circular RNAs (circRNAs) may be involved in tumorigenesis. Recently, the role of circRNAs in hepatocellular carcinoma (HCC) has drawn wide attention. Herein, we aimed to explore the regulation and function of hsa_circ_0005239 in the malignant biological behavior and angiogenesis of HCC, as well as the link between hsa_circ_0005239 and programmed cell death ligand 1 (PD-L1) in HCC. Quantitative real-time polymerase chain reaction (qRT-PCR) assays revealed that hsa_circ_0005239 was upregulated in HCC tumor samples and cell lines. Furthermore, a series of in vitro and in vivo assays explored the effects of hsa_circ_0005239 on biological processes involved in the development of HCC. Knockdown of hsa_circ_0005239 significantly inhibited cell migration, cell invasion, and angiogenesis in HCC, while overexpression showed the opposite effect. In the in vivo assays, hsa_circ_0005239 downregulation suppressed the growth of xenograft tumors in nude mice, which supported that hsa_circ_0005239 is a tumor promoter in HCC. Mechanistically, hsa_circ_0005239 binds to miR-34a-5p and functions as a competing endogenous RNA to modulate the expression of PD-L1. Further experiments revealed that the hsa_circ_0005239/PD-L1 axis regulates the malignant phenotypes of HCC cells through the phosphoinositide-3 kinase/protein kinase B (PI3K/Akt) signaling pathway. These results revealed the role of hsa_circ_0005239 and the hsa_circ_0005239/miR-34a-5p/PD-L1 axis in HCC, providing a potential diagnostic biomarker and therapeutic target for HCC.

He T ，Huang J ，Liang H ，Zhong B ，Xu G ，Zhu X ... -  《-》

Downregulation of hsa_circ_0074854 Suppresses the Migration and Invasion in Hepatocellular Carcinoma via Interacting with HuR and via Suppressing Exosomes-Mediated Macrophage M2 Polarization.

Circular RNAs (circRNAs) have been identified as key factors in the development of hepatocellular carcinoma (HCC). However, the role and potential molecular mechanism of circRNAs in HCC remain largely unclear. In addition, exosomes are known as important messengers of the cross-talk between tumor cells and immune cells, while the role of extracellular circRNAs in the cell-to-cell communication of tumor cells and immune cells remains not unclear. The level of hsa_circ_0074854 in HCC cell lines and HCC cell-derived exosomes was assessed using RT-qPCR assay. In addition, CCK-8 and transwell assays were used to determine the viability, migration and invasion of HCC cells. Hsa_circ_0074854 expression was upregulated in HCC tissues and HCC cell lines. Additionally, hsa_circ_0074854 knockdown was found to inhibit HCC growth in vitro and in vivo. Mechanistically, hsa_circ_0074854 knockdown inhibited the migration and invasion of HCC cells via interacting with human antigen R (HuR) to reduce its stability. Furthermore, hsa_circ_0074854 can be transferred from HCC cells to macrophages via exosomes. Exosomes with downregulated hsa_circ_0074854 suppressed macrophage M2 polarization, which in turn suppressing migration and invasion of HCC cells both in vitro and in vivo. Downregulation of hsa_circ_0074854 suppresses the migration and invasion in hepatocellular carcinoma via interacting with HuR and via suppressing exosomes-mediated macrophage M2 polarization. Collectively, these findings may help to understand the diagnosis and treatment of HCC.

Wang Y ，Gao R ，Li J ，Tang S ，Li S ，Tong Q ，Li S ... -  《International Journal of Nanomedicine》

Hsa_circ_0079875 functions as a competitive endogenous RNA to promote hepatocellular carcinoma progression.

Liu Y ，Luo X ，Chen W ，Dong Z ，Cheng T ，Chen L ，Ju L ，Cai W ，Bian Z ... -  《-》

Oncogenic hsa_circ_0091581 promotes the malignancy of HCC cell through blocking miR-526b from degrading c-MYC mRNA.

Wei X ，Zheng W ，Tian P ，He Y ，Liu H ，Peng M ，Li X ，Liu X ... -  《-》