circEPSTI1 Acts as a ceRNA to Regulate the Progression of Osteosarcoma.

Recent studies have reported the vital roles of circular RNAs (circRNAs) in tumor progression. However, the function and expression profile of most circRNAs in osteosarcoma remain unclear. We examined the expression of circEPSTI1, a circRNA, in 50 paired adjacent normal tissues and osteosarcoma tissues by qRT-PCR. Then, we further explored the function of circEPSTI1 in osteosarcoma progression in vitro and in vivo. For example, cell proliferation and migration were examined. Some experiments were performed to explore the regulatory function of circEPSTI1 in miRNA and to investigate the potential role of circEPSTI1 in osteosarcoma. We found that circEPSTI1 was significantly upregulated in osteosarcoma. Inhibition of circEPSTI1 suppressed the osteosarcoma cancer cell proliferation and migration in vitro. Dual luciferase reporter assay showed that circEPSTI1 and MCL1 (myeloid cell leukaemia 1) could bind to miR-892b and that MCL1 and circEPSTI1 were targets of miR-892b. Thus, the circEPSTI1-miR-892b-MCL1 axis affected osteosarcoma progression through the miRNA sponging mechanism. circEPSTI1 may serve as a target and biomarker for osteosarcoma treatment.

Tan X ，Tan D ，Li H ，Lin Y ，Wen Z ，Zeng C ... -  《-》

circEPSTI1 regulates ovarian cancer progression via decoying miR-942.

Increasing studies show that circular RNAs (circRNAs) play vital roles in tumour progression. But, how circRNAs function in ovarian cancer is mostly unclear. Here, we detected the expression of circEPSTI1 in ovarian cancer and explored the function of circEPSTI1 in ovarian cancer via a series of experiments. Then, we performed luciferase assay and RNA immunoprecipitation (RIP) assay to explore the competing endogenous RNA (ceRNA) function of circEPSTI1 in ovarian cancer. qRT-PCR verified that circEPSTI1 was overexpressed in ovarian cancer. Inhibition of circEPSTI1 suppressed ovarian cancer cell proliferation, invasion but promoted cell apoptosis. Luciferase assays and RIP assay showed that circEPSTI1 and EPSTI1 (epithelial stromal interaction 1) could directly bind to miR-942. And circEPSTI1 could regulate EPSTI1 expression via sponging miR-942. In summary, circEPSTI1 regulated EPSTI1 expression and ovarian cancer progression by sponging miR-942. circEPSTI1 could be used as a biomarker and therapeutic target in ovarian cancer.

Xie J ，Wang S ，Li G ，Zhao X ，Jiang F ，Liu J ，Tan W ... -  《-》

Hsa_circ_0008934 promotes the proliferation and migration of osteosarcoma cells by targeting miR-145-5p to enhance E2F3 expression.

To investigate the role of hsa_circ_0008934 in osteosarcoma and the molecular mechanism involved in the regulation of the occurrence and development of osteosarcoma METHODS: Differentially expressed circRNAs in the osteosarcoma cell lines SaOS2 and MG63 and in the normal human osteoblast cell line hFOB1.19 were identified via next-generation RNA sequencing. The expression and circular morphology of hsa_circ_0008934 were analyzed via quantitative real-time polymerase chain reaction (qRT-PCR) and RT-PCR analysis, respectively. Proliferation, apoptosis, cell cycle progression, migration, and invasion of SaOS2 and MG63 cells with hsa_circ_0008934 silencing or overexpression were assessed using the MTS method, colony formation assay, flow cytometry, and the transwell system, respectively. The subcellular distribution of hsa_circ_0008934 was revealed via fluorescence in situ hybridization. The binding of hsa_circ_0008934 with microRNAs was confirmed using the dual-luciferase reporter assay. The oncogenic roles of hsa_circ_0008934 in osteosarcoma were determined using an in vivo tumorigenesis assay with nude mice. qRT-PCR, western blotting, TUNEL assay, and immunohistochemistry (IHC) were used to detect the tumorigenicity of hsa_circ_0008934 in osteosarcoma cells. Many circRNAs were differentially expressed in SaOS2 and MG63 cells than in hFOB1.19 cells. Hsa_circ_0008934 expression was significantly elevated in SaOS2 and MG63 cells. Hsa_circ_0008934 silencing significantly reduced proliferation, enhanced apoptosis, blocked cell cycle progression, and impaired migration and invasion capacities of SaOS2 cells. Opposite cellular alterations were achieved by overexpressing hsa_circ_0008934 in MG63 cells. Hsa_circ_0008934 was mainly distributed in the cytosol and positively regulated E2F3 expression in osteosarcoma cells. In addition, it directly bound with miR-145-5p to repress E2F3 expression and enhanced the tumorigenesis of MG63 cells in nude mice. qRT-PCR revealed that the intracellular injection of hsa_circ_0008934 lentivirus resulted in hsa_circ_0008934 overexpression and miR-145-5p downregulation. Western blotting confirmed that E2F3 was upregulated. Moreover, the TUNEL assay showed that hsa_circ_0008934 overexpression inhibited the apoptosis of tumor cells. IHC detection revealed that the hsa_circ_0008934 overexpression could promote the expression of Ki67 and PCNA. Elevated hsa_circ_0008934 expression promotes the proliferation and migration of osteosarcoma cells by sponging miR-145-5p to enhance E2F3 expression.

Li S ，Zeng M ，Yang L ，Tan J ，Yang J ，Guan H ，Kuang M ，Li J ... -  《-》

circEPSTI1 as a Prognostic Marker and Mediator of Triple-Negative Breast Cancer Progression.

Chen B ，Wei W ，Huang X ，Xie X ，Kong Y ，Dai D ，Yang L ，Wang J ，Tang H ，Xie X ... -  《Theranostics》

Circular RNA_CNST Promotes the Tumorigenesis of Osteosarcoma Cells by Sponging miR-421.

Wang JH ，Wu XJ ，Duan YZ ，Li F ... -  《-》