WITHDRAWN: GAS5 enhances natural killer cell-mediated killing by promoting ubiquitination of SESN2 in prostate cancer cells.

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HIF1α promotes prostate cancer progression by increasing ATG5 expression.

Prostate cancer (PCa) is the most frequently diagnosed cancer among men. However, the major modifiable risk factors for PCa are poorly known and its specific mechanism of progression remains unclear. Here we reported that, in prostate cancer cells, the autophagy level was elevated under hypoxic condition, as well as the mRNA and protein level of ATG5, which is an important gene related to autophagy. Furthermore, we found HIF1α could directly bind to the promoter of ATG5 and promote the expression of ATG5 on transcriptional level by luciferase assay and ChIP assay. Intriguingly, overexpression of HIF1α by HIF1α-M could increase tumor size and the effect could be abolished by knockdown ATG5 by si-ATG5 in BALB/cA-nu/nu nude mice. Importantly, HIF1α could also promote the metastasis of PC-3 cells by upregulating the ATG5 and autophagy level and knockdown ATG5 and inhibition autophagy both could abolish the effect of overexpression of HIF1α on the migration of PC-3 cells. Taken together, our results, for the first time, proved that HIF1α could promote the proliferation and migration of PC-3 cells by direct upregulating ATG5 and autophagy level in PC-3 prostate cancer cells. Our findings not only provide new perspective for the relationship between hypoxia and autophagy, but also add new potential therapeutic regimens for the treatment of prostate cancers.

LncRNA GAS5 enhanced the killing effect of NK cell on liver cancer through regulating miR-544/RUNX3.

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.

MiR-10a functions as a tumor suppressor in prostate cancer via targeting KDM4A.

Deregulation of microRNAs contributes to the abnormal cell growth which is frequently observed in cancer. In the current study, we detected the expression and regulatory relationship between miR-10a and Lysine-specific demethylase 4A (KDM4A) to reveal their function in prostate cancer (PCa) progression. We found that miR-10a levels were significantly decreased in PCa cell lines in comparison with the normal epithelial cell line RWPE-1. Downregulation of miR-10a levels was also observed in tumor tissues from PCa patients compared with the adjacent normal tissues. Enhanced expression of miR-10a inhibited cell proliferation and colony forming capability of PCa cells. In addition, quantitative real-time polymerase chain reaction and Western blot analysis showed a significant decrease of KDM4A in response to miR-10a elevation in PCa cells. Using dual luciferase assay, we confirmed that KDM4A was a target gene for miR-10a. Furthermore, Western blot analysis indicated that miR-10a overexpression inactivated YAP signaling and suppressed transcription of YAP target genes. Additionally, cell growth arrest and colony forming capacity inhibition induced by miR-10a overexpression could be reversed by YAP overexpression in PCa cells. More importantly, miR-10a mimics inhibited PC-3 tumor growth in nude mice accompanied with a remarkable reduction of KDM4A and YAP expression. In conclusion, our results uncovered a tumor suppressor role of miR-10a in PCa via negative regulation of KDM4A and its downstream Hippo-YAP pathway.

IRE1α-XBP1 signaling pathway regulates IL-6 expression and promotes progression of hepatocellular carcinoma.

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 XBP1 and interleukin (IL)-6 in human tissues and cells. ChIP and luciferase reporter assays were utilized to investigate the interaction between XBP1s and IL-6 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 (r2=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.

HIF-1α induces immune escape of prostate cancer by regulating NCR1/NKp46 signaling through miR-224.

BACKGROUND: Metastasis of prostate cancer (PCa) is largely affected by natural killer (NK) cells. This study aimed to clarify the mechanisms underlying tumor cells escaping from NK cells mediated by HIF-1α. METHODS: MiR-224 expression in lymphocytes and HIF-1α protein level in NK cells were determined by qRT-PCR and western blot, respectively. The amount of NKp46+ NK cells was detected with flow cytometry. The IFN-γ level was examined by enzyme linked immunosorbent assay (ELISA). NK cells were tested for cytolytic activity with a Non-Radioactive Cytotoxicity Assay, and treated with oxygenglucose deprivation (OGD) for hypoxia simulation. Interaction between miR-224 and NCR1 was evaluated with dual luciferase reporter assay. RESULTS: MiR-224 was down-regulated in lymphocytes isolated from prostate cancer tissues (n = 10). Overexpression of miR-224 protected prostate cancer from NK cells. HIF-1α increased miR-224 to inhibit the killing capability of NK cells on prostate cancer. MiR-224 controlled the expression of NCR1. Overexpression of miR-224 protected prostate cancer from NK cells through NCR1/NKp46 signaling. Suppression of HIF-1α enhanced the cytotoxicity of NK cells on prostate cancer via miR-224/NCR1 pathway. CONCLUSION: HIF-1α inhibits NCR1/NKp46 pathway through up-regulating miR-224, which affects the killing capability of NK cells on prostate cancer, thus inducing immune escape of tumor cells.

MiR-544 promotes immune escape through downregulation of NCR1/NKp46 via targeting RUNX3 in liver cancer.

OBJECTIVE: To study the potential role of miR-544 in the immune escape mechanism of hepatoma cells. METHODS: Natural 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. RESULTS: MiR-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. CONCLUSION: miR-544 promoted the immune escape of liver cancer cells by downregulating NCR1 via targeting RUNX3.