This study aimed to explore the role of lncRNA GAS5 in the regulation of the killing effect of NK cells on liver cancer. Compared with a control group, lncRNA GAS5, RUNX3, and NCR1 were down-regulated in NK cells of patients with liver cancer, whereas miR-544 expression was up-regulated in NK cells of patients with liver cancer. Activated NK cells had higher IFN-γ level. Knockdown of GAS5 in activated NK cells decreased IFN-γ secretion, NK cell cytotoxicity, the percentage of CD107a+ NK cells, and the apoptosis rate of HepG2 and Huh7 cells. We also proved the interaction of GAS5 and miR-544, and the negative regulation role of GAS5 on miR-544. GAS5 overexpression in activated NK cells increased RUNX3 expression, IFN-γ secretion, the NK cell cytotoxicity, the percentage of CD107a+ NK cells, and the apoptosis rate of HepG2 cells, while miR-544 mimic abolished the promotion effect of GAS5 overexpression. Finally, in vivo experiments indicated an inhibition effect of GAS5 in tumor growth. LncRNA GAS5 overexpression enhances the killing effect of NK cell on liver cancer through regulating miR-544/RUNX3.

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Of the three unfolded protein response pathways, which are activated by endoplasmic reticulum stress, inositol-requiring enzyme 1α (IRE1α)-X-box-binding protein 1 (XBP1) signaling is the most conserved. These pathways are implicated in a variety of types of cancer, including hepatocellular carcinoma (HCC). However, the role of IRE1α-XBP1 signaling in the development of HCC remains unclear. In the current study, reverse transcription-quantiative polymerase chain reaction was used to analyze the expression levels of and interleukin ( in human tissues and cells. ChIP and luciferase reporter assays were utilized to investigate the interaction between XBP1s and promoter DNA. It was revelaed that IRE1α-XBP1 signaling promotes the proliferation of HCC cells via regulating hepatic IL-6 expression. It was observed that the splicing levels of XBP1 and hepatic IL-6 content were increased and positively correlated with each other in human HCC tissues (r=0.5846, P=0.004). Ectopic expression of IRE1α or XBP1s increased IL-6 levels in LO2 and Hep3B cells. In addition, pharmacological inhibition of IRE1α reduced the levels of IL-6 expression and secretion through blocking the generation of XBP1s, which bound directly to the IL-6 promoter and activated its expression. Further investigation demonstrated that IL-6 driven by XBP1s was secreted outside of cells and activated signal transducer and activator of transcription 3 (STAT3) signaling in an autocrine/paracrine manner, to regulate the proliferation of Hep3B cells. Blockage of IL-6-STAT3 signaling with tocilizumab attenuated the effect of IRE1α-XBP1 signaling in promoting Hep3B cell proliferation. In conclusion, the present study revealed that IRE1α-XBP1 signaling promotes carcinogenesis of HCC by regulating the activation of the IL-6-STAT3 signaling pathway.

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ObjectiveTo study the potential role of miR-544 in the immune escape mechanism of hepatoma cells.MethodsNatural killer (NK) cells were collected from healthy volunteers and patients with liver cancer. Interleukin (IL)-2 activated-NK-92 cells were transfected with miR-544 inhibitor/mimic or NC/pre-NC in HepG2 co-culture system. NK-92 cells were treated with control, IL-2, IL-2 + pre-NC, IL-2 + miR-544 mimic, IL-2 + miR-544 mimic + pcDNA and IL-2 + miR-544 mimic + pcDNA-runt-related transcription factor 3 (RUNX3) groups. Mice models of liver cancer were well established. Expression of miR-544, natural cytotoxicity receptor 1 (NCR1) and RUNX3 were evaluated by quantitative real-time PCR and western blotting. Flow cytometry and ELISA were used to determine NK cell cytotoxicity and the levels of INF-γ, respectively.ResultsMiR-544 was upregulated while NCR1 and RUNX3 was downregulated in NK cells of patients with liver cancer. The levels of IFN-γ and miR-544 expression were increased and decreased in IL-2 activated-NK cells, respectively. Inversely, miR-544 overexpression inhibited NK cell cytotoxicity by downregulating IFN-γ. However, miR-544 directly targeted RUNX3 and negatively regulated NCR1. Furthermore, miR-544 promoted immune escape of hepatoma cells in vivo and in vitro.ConclusionmiR-544 promoted the immune escape of liver cancer cells by downregulating NCR1 via targeting RUNX3.