Long Non-Coding RNA CASC7 Promotes Proliferation and Inhibits Apoptosis of Hepatocellular Carcinoma Cells via Downregulating miR-340-5p CASC7/miR-340-5p Axis in Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is a common malignant tumor worldwide with a poor prognosis. Amounting studies revealed that long non-coding RNAs (lncRNAs) show important roles in various biological processes. The purpose of this study was to explore the biological function and potential molecular mechanism of CASC7 in HCC. Methods: CASC7 expression in HCC cell lines was detected by qRT-PCR. The expressions of CASC7 and miR-340-5p were changed by transfection of miR-340-5p mimic, the CASC7 overexpression and knockdown plasmids. The interaction between CASC7 and miR-340-5p was assessed by a Dual-Luciferase reporter assay. The biological functions of CASC7 were evaluated by CCK-8, colony formation assay, ROS assay kit, immunofluorescence and flow cytometry (FCM). Results: CASC7 was upregulated in HCC cell lines. CASC7 overexpression significantly promoted cell proliferation, as well as inhibited apoptosis and oxidative stress. In contrast, CASC7 knockdown could reverse these above changes. The result of the Dual-luciferase reporter assay revealed that CASC7 directly targeted miR-340-5p and negatively regulated its expression. In addition, CASC7 promoted proliferation and inhibited apoptosis of HCC cells through activating Nrf2 pathway by downregulating miR-340-5p. Conclusions: In summary, CASC7 promotes HCC tumorigenesis and progression through the Nrf2 pathway by targeting miR-340-5p, which may provide a new target for therapy of HCC.

Effect and Mechanism of LncRNA HOTAIR on Migration, Apoptosis and Proliferation of Hepatocellular Carcinoma Cells

<sec> <title>Objective:</title> This study was designed to probe the influence and mechanism of lncRNA HOTAIR on migration, apoptosis and proliferation of hepatocellular carcinoma (HCC) cells. </sec> <sec> <title>Methods:</title> We evaluated LncRNA HOTAIR expression in HCC tissues and adjacent tissues, and serum of HCC patients and healthy controls. Later, we knocked down lncRNA HOTAIR, and utilized CCK-8 to determine Hep3B cell proliferation, flow cytometry for prospecting Hep3B cell apoptosis, and cell scratch assay for observing Hep3B cell migration.We anticipated the direct target of lncRNA HOTAIR, and adopted luciferase reporter assay to verify. Moreover, we inhibitedmiR-126-5p expression, and rescue experiment for evaluating the influence of si-HOTAIR+miR-126-5p inhibitors on Hep3B cell migration, apoptosis as well as proliferation. </sec> <sec> <title>Results:</title> Our results showed that lncRNA HOTAIR expression in tumor tissues and serum was significantly increased. Moreover, lncRNA HOTAIR inhibition significantly decreased the Hep3B cell proliferation rate, elevated Hep3B cell apoptosis rate, and inhibited Hep3B cell migration. Luciferase reporter assay suggested that miR-126-5p was the direct target of lncRNA HOTAIR. Furthermore, co-transfection of si-HOTAIR+miR-126-5p inhibitor could diminishthe effects of HOTAIR silencing on apoptosis, proliferation and migration. </sec> <sec> <title>Conclusion:</title> Silencing of lncRNA-HOTAIR can inhibit the HCC cell migration and proliferation, and increase the apoptosis by up-regulating miR-126-5p expression. </sec>