The role of TGF-β-induced epithelial-mesenchymal transition (EMT) in cancer cell dissemination is well established, but the involvement of lncRNAs in TGF-β signaling is still unknown. In this study, we observed that the lncRNA-activated by TGF-β (lncRNA-ATB) was upregulated in hepatocellular carcinoma (HCC) metastases and associated with poor prognosis. lncRNA-ATB upregulated ZEB1 and ZEB2 by competitively binding the miR-200 family and then induced EMT and invasion. In addition, lncRNA-ATB promoted organ colonization of disseminated tumor cells by binding IL-11 mRNA, autocrine induction of IL-11, and triggering STAT3 signaling. Globally, lncRNA-ATB promotes the invasion-metastasis cascade. Thus, these findings suggest that lncRNA-ATB, a mediator of TGF-β signaling, could predispose HCC patients to metastases and may serve as a potential target for antimetastatic therapies.

BACKGROUND The liver is frequently subject to insult because of viral infection, alcohol abuse, or toxic chemical exposure. Extensive research has been conducted to identify blood markers that can better discern liver damage, but little progress has been achieved in clinical practice. Recently, circulating microRNAs (miRNAs) have been reported as potential biomarkers for the noninvasive diagnosis of cancer. In this study, we investigated whether plasma miRNAs have diagnostic utility in identifying liver disease. METHODS The study was divided into 2 phases: marker selection by real-time quantitative PCR analysis of a small set of plasma samples, and marker validation with a large set of plasma samples from 83 patients with chronic hepatitis B viral infections, 15 patients with skeletal muscle disease, and 40 healthy controls. Two mouse model systems, d-galactosamine- and alcohol-induced liver injury, were also developed to evaluate whether differences in miRNA concentration were associated with various liver diseases. RESULTS Among the miRNA candidates identified, miR-122 presented a disease severity–dependent change in plasma concentration in the patients and animal models. Compared with an increase in aminotransferase activity in the blood, the change in miR-122 concentration appeared earlier. Furthermore, this change was more specific for liver injury than for other organ damage and was more reliable, because the change was correlated with liver histologic stage. CONCLUSIONS Our findings suggest that circulating miR-122 has potential as a novel, predictive, and reliable blood marker for viral-, alcohol-, and chemical-induced liver injury.

The hepatitis B virus X protein (HBx) has been implicated as an oncogene in both epigenetic modifications and genetic regulation during hepatocarcinogenesis, but the underlying mechanisms are not entirely clear. Long noncoding RNAs (lncRNAs), which regulate gene expression with little or no protein-coding capacity, are involved in diverse biological processes and in carcinogenesis. We asked whether HBx could promote hepatocellular carcinoma (HCC) by regulating the expression of lncRNAs. In this study we investigated the alteration in expression of lncRNAs induced by HBx using microarrays and real-time quantitative polymerase chain reaction (PCR). Our results indicate that HBx transgenic mice have a specific profile of liver lncRNAs compared with wildtype mice. We identified an lncRNA, down-regulated expression by HBx (termed lncRNA-Dreh), which can inhibit HCC growth and metastasis in vitro and in vivo, act as a tumor suppressor in the development of hepatitis B virus (HBV)-HCC. LncRNA-Dreh could combine with the intermediate filament protein vimentin and repress its expression, and thus further change the normal cytoskeleton structure to inhibit tumor metastasis. We also identified a human ortholog RNA of Dreh (hDREH) and found that its expression level was frequently downregulated in HBV-related HCC tissues in comparison with the adjacent noncancerous hepatic tissues, and its decrement significantly correlated with poor survival of HCC patients. Conclusion: These findings support a role of lncRNA-Dreh in tumor suppression and survival prediction in HCC patients. This discovery contributes to a better understanding of the importance of the deregulated lncRNAs by HBx in HCC and provides a rationale for the potential development of lncRNA-based targeted approaches for the treatment of HBV-related HCC. (HEPATOLOGY 2013;57:1882-1892 A s one of the most common malignancies in the world, hepatocellular carcinoma (HCC) has a very high morbidity and mortality. It is a major global health challenge that affects an estimated 500,000 people worldwide each year.1 The leading cause of HCC is attributable to persistent hepatitis B virus (HBV) infection, which can result in endstage liver disease, including liver cirrhosis and HCC. The smallest open reading frame of the HBV genome, HBX, encodes the hepatitis B virus X protein (HBx) and has been implicated in hepatocarcinogenesis and considered to be oncogenic.2 Furthermore, it has been observed that about 60% of HBx transgenic mice develop HCC after the age of 18 months and that some of these tumors eventually metastasize, which Abbreviations: Dreh, down-regulated expression by HBx EMT, epithelial-to-mesenchymal transition; HBx, hepatitis B virus X protein; HCC, hepatocellular carcinoma; H&E, hematoxylin and eosin; IF, intermediate filament; lncRNA, long noncoding RNA; OS, overall survival; qRT-PCR, quantitative reverse transcription-polymerase chain reaction; RACE, rapid amplification of cDNA ends; RIP, RNA immunoprecipitation; RFS, recurrence-free survival.From the

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