Tumor cells with stemness (stem‐cell) features contribute to initiation and progression of hepatocellular carcinoma (HCC), but involvement of long noncoding RNAs (lncRNAs) remains largely unclear. ...Genome‐wide analyses were applied to identify tumor‐associated lncRNA‐DANCR. DANCR expression level and prognostic values of DANCR were assayed in two HCC cohorts (China and Korea, n = 135 and 223). Artificial modulation of DANCR (down‐ and overexpression) was done to explore the role of DANCR in tumorigenesis and colonization, and tumor‐bearing mice were used to determine therapeutic effects. We found that lncRNA‐DANCR is overexpressed in stem‐like HCC cells, and this can serve as a prognostic biomarker for HCC patients. Experiments showed that DANCR markedly increased stemness features of HCC cells to promote tumorigenesis and intra‐/extrahepatic tumor colonization. Conversely, DANCR knockdown attenuated the stem‐cell properties and in vivo interference with DANCR action led to decreased tumor cell vitality, tumor shrinkage, and improved mouse survival. Additionally, we found that the role of DANCR relied largely on an association with, and regulation of, CTNNB1. Association of DANCR with CTNNB1 blocked the repressing effect of microRNA (miR)−214, miR‐320a, and miR‐199a on CTNNB1. This observation was confirmed in vivo, suggesting a novel mechanism of tumorigenesis involving lncRNAs, messenger RNAs, and microRNAs. Conclusions: These studies reveal a significance and mechanism of DANCR action in increasing stemness features and offer a potential prognostic marker and a therapeutic target for HCC. (Hepatology 2016;63:499–511)
Many protein‐coding oncofetal genes are highly expressed in murine and human fetal liver and silenced in adult liver. The protein products of these hepatic oncofetal genes have been used as clinical ...markers for the recurrence of hepatocellular carcinoma (HCC) and as therapeutic targets for HCC. Herein we examined the expression profiles of long noncoding RNAs (lncRNAs) found in fetal and adult liver in mice. Many fetal hepatic lncRNAs were identified; one of these, lncRNA‐mPvt1, is an oncofetal RNA that was found to promote cell proliferation, cell cycling, and the expression of stem cell‐like properties of murine cells. Interestingly, we found that human lncRNA‐hPVT1 was up‐regulated in HCC tissues and that patients with higher lncRNA‐hPVT1 expression had a poor clinical prognosis. The protumorigenic effects of lncRNA‐hPVT1 on cell proliferation, cell cycling, and stem cell‐like properties of HCC cells were confirmed both in vitro and in vivo by gain‐of‐function and loss‐of‐function experiments. Moreover, mRNA expression profile data showed that lncRNA‐hPVT1 up‐regulated a series of cell cycle genes in SMMC‐7721 cells. By RNA pulldown and mass spectrum experiments, we identified NOP2 as an RNA‐binding protein that binds to lncRNA‐hPVT1. We confirmed that lncRNA‐hPVT1 up‐regulated NOP2 by enhancing the stability of NOP2 proteins and that lncRNA‐hPVT1 function depends on the presence of NOP2. Conclusion: Our study demonstrates that the expression of many lncRNAs is up‐regulated in early liver development and that the fetal liver can be used to search for new diagnostic markers for HCC. LncRNA‐hPVT1 promotes cell proliferation, cell cycling, and the acquisition of stem cell‐like properties in HCC cells by stabilizing NOP2 protein. Regulation of the lncRNA‐hPVT1/NOP2 pathway may have beneficial effects on the treatment of HCC. (Hepatology 2014;60:1278–1290)
In recent years, long noncoding RNAs (lncRNAs) have been shown to have critical regulatory roles in cancer biology. However, the contributions of lncRNAs to hepatitis B virus (HBV)‐related ...hepatocellular carcinoma (HCC) remain largely unknown. Differentially expressed lncRNAs between HBV‐related HCC and paired peritumoral tissues were identified by microarray and validated using quantitative real‐time polymerase chain reaction. Liver samples from patients with HBV‐related HCC were analyzed for levels of a specific differentially expressed lncRNA High Expression In HCC (termed lncRNA‐HEIH); data were compared with survival data using the Kaplan‐Meier method and compared between groups by the log‐rank test. The effects of lncRNA‐HEIH were assessed by silencing and overexpressing the lncRNA in vitro and in vivo. The expression level of lncRNA‐HEIH in HBV‐related HCC is significantly associated with recurrence and is an independent prognostic factor for survival. We also found that lncRNA‐HEIH plays a key role in G0/G1 arrest, and further demonstrated that lncRNA‐HEIH was associated with enhancer of zeste homolog 2 (EZH2) and that this association was required for the repression of EZH2 target genes. Conclusions: Together, these results indicate that lncRNA‐HEIH is an oncogenic lncRNA that promotes tumor progression and leads us to propose that lncRNAs may serve as key regulatory hubs in HCC progression. (HEPATOLOGY 2011
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 down‐regulated 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)
Background and Aims
HBV‐pgRNA (pregenomic RNA) has been proposed for predicting the response of nucleos(t)ide analogue (NA) treatment, guiding discontinuation of NA therapy and monitoring the ...emergence of viral mutations. However, the contributions of HBV‐pgRNA to HCC remain open for study.
Approach and Results
Double‐center cohorts of serum samples with undetectable serum HBV‐DNA (below the lower limit of detection) were obtained from long‐term NA‐treated (≥48 weeks) HBV‐related HCC patients. The correlation between serum pgRNA concentration and the prognosis of HCC were analyzed. The role pgRNA played in HCC development was assessed both in vitro and in vivo. Our findings revealed that for patients who underwent long‐term NA therapy with undetectable serum HBV‐DNA, patients with high serum pgRNA expression had a poorer overall survival rate and higher cumulative recurrence rate after hepatectomy. Experiments demonstrated that pgRNA promotes proliferation, stemness, and tumorigenicity of HCC cells. Mechanistically, we found that pgRNA could up‐regulate the expression of insulin‐like growth factor 2 mRNA‐binding protein 3 (IGF2BP3), a well‐proven oncoprotein, at the posttranscriptional level. Furthermore, interferon (IFN)‐α‐2a could degrade the stability of pgRNA through increasing its N6‐methyladenosine (m6A) RNA modification. Collectively, our findings uncover that serum pgRNA could serve as a potential biomarker for predicting the prognosis and recurrence of HCC in patients who received long‐term NA therapy with undetectable serum HBV‐DNA; and the pgRNA‐IGF2BP3 axis plays an important role in the development of HBV‐related HCC. Moreover, IFN‐α‐2a could reduce the stability of pgRNA by increasing its m6A RNA modification level, thereby suppressing the development of HBV‐related HCC.
Conclusions
In conclusion, our studies reveal a significance and mechanism of HBV‐pgRNA in increasing stemness features and offer a potential prognostic marker and a therapeutic target for HBV‐related HCC.
Recently, long noncoding RNAs (lncRNAs) were found to be dysregulated in a variety of tumors. However, it remains unknown how and through what molecular mechanisms the expression of lncRNAs is ...controlled. In this study, we found that the lncRNA Low Expression in Tumor (lncRNA-LET) was generally downregulated in hepatocellular carcinomas, colorectal cancers, and squamous-cell lung carcinomas. We demonstrated that hypoxia-induced histone deacetylase 3 repressed lncRNA-LET by reducing the histone acetylation-mediated modulation of the lncRNA-LET promoter region. Interestingly, the downregulation of lncRNA-LET was found to be a key step in the stabilization of nuclear factor 90 protein, which leads to hypoxia-induced cancer cell invasion. Moreover, the relationship among hypoxia, histone acetylation disorder, low lncRNA-LET expression level, and metastasis was found in clinical hepatocellular carcinoma samples. These results advance our understanding of the role of lncRNA-LET as a regulator of hypoxia signaling and offer new avenues for therapeutic intervention against cancer progression.
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► There is low expression of lncRNA-LET in various tumor tissues ► Hypoxia-induced low expression of lncRNA-LET occurred through histone deacetylase 3 ► The lncRNA-LET is bound to NF90, which increases NF90 degradation by the proteasome ► Low lncRNA-LET expression contributes to hypoxia-induced cell invasion
Although numerous long non-coding RNAs (lncRNAs) have been identified in mammals, many of their biological roles remain to be characterized. Early reports suggest that H19 contributes to ...carcinogenesis, including hepatocellular carcinoma (HCC). Examination of the Oncomine resource showed that most HCC cases express H19 at a level that is comparable with the liver, with a tendency toward lower expression. This is consistent with our previous microarray data and indicates a more complicated role of H19 in HCC that needs to be characterized. In this study, the expression level of H19 was assessed in different regions of HCC patients' liver samples. Loss- and gain-of-function studies on this lncRNA in the HCC cell lines, SMMC7721 and HCCLM3, were used to characterize its effects on gene expression and to assess its effect on HCC metastasis both in vitro and in vivo. In this study, we show that H19 was underexpressed in intratumoral HCC tissues (T), as compared with peritumoral tissues (L). Additionally, low T/L ratio of H19 predicted poor prognosis. H19 suppressed HCC progression metastasis and the expression of markers of epithelial-to-mesenchymal transition. Furthermore, H19 associated with the protein complex hnRNP U/PCAF/RNAPol II, activating miR-200 family by increasing histone acetylation. The results demonstrate that H19 can alter the miR-200 pathway, thus contributing to mesenchymal-to-epithelial transition and to the suppression of tumor metastasis. These data provide an explanation for the hitherto puzzling literature on the relationship between H19 and cancer, and could suggest the development of combination therapies that target H19 and the miR-200 family.
Survival of patients with hepatocellular carcinoma (HCC) remains poor, which is largely attributed to active angiogenesis. However, the mechanisms underlying angiogenesis in HCC remain to be ...discovered. In this study, we found that long noncoding RNA associated with microvascular invasion in HCC (lncRNA MVIH) (lncRNA associated with microvascular invasion in HCC) was generally overexpressed in HCC. In a cohort of 215 HCC patients, the overexpression of MVIH was associated with frequent microvascular invasion (P = 0.016) and a higher tumor node metastasis stage (P = 0.009) as well as decreased recurrence‐free survival (RFS) (P < 0.001) and overall survival (P = 0.007). Moreover, the up‐regulation of MVIH served as an independent risk factor to predict poor RFS. We also found that MVIH could promote tumor growth and intrahepatic metastasis by activating angiogenesis in mouse models. Subsequent investigations indicated that MVIH could activate tumor‐inducing angiogenesis by inhibiting the secretion of phosphoglycerate kinase 1 (PGK1). Additionally, in 65 HCC samples, MVIH expression was inversely correlated with the serum level of PGK1 and positively correlated with the microvessel density. Conclusion: Deregulation of lncRNA MVIH is a predictor for poor RFS of HCC patients after hepatectomy and could be utilized as a potential target for new adjuvant therapies against active angiogenesis. (HEPATOLOGY 2012;56:2142–2153)
Hepatitis B virus (HBV) can integrate into the human genome, contributing to genomic instability and hepatocarcinogenesis. Here by conducting high-throughput viral integration detection and RNA ...sequencing, we identify 4,225 HBV integration events in tumour and adjacent non-tumour samples from 426 patients with HCC. We show that HBV is prone to integrate into rare fragile sites and functional genomic regions including CpG islands. We observe a distinct pattern in the preferential sites of HBV integration between tumour and non-tumour tissues. HBV insertional sites are significantly enriched in the proximity of telomeres in tumours. Recurrent HBV target genes are identified with few that overlap. The overall HBV integration frequency is much higher in tumour genomes of males than in females, with a significant enrichment of integration into chromosome 17. Furthermore, a cirrhosis-dependent HBV integration pattern is observed, affecting distinct targeted genes. Our data suggest that HBV integration has a high potential to drive oncogenic transformation.
Hepatitis B protein x (HBx) has been reported to promote tumorigenesis in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), but the mechanism awaits further investigation. In this ...study, we found that cFAM210A (a circular RNA derived from the third exon of transcript NM_001098801 of the FAM210A gene; CircBase ID: hsa_circ_0003979) can be silenced by HBx. cFAM210A expression was downregulated and negatively correlated with tumorigenesis in patients with HBV-related HCC. Furthermore, cFAM210A reduced the proliferation, stemness, and tumorigenicity of HCC cells. Mechanistically, HBx increased the N6-methyladenosine (m6A) level of cFAM210A by promoting the expression of RBM15 (an m6A methyltransferase), thus inducing the degradation of cFAM210A via the YTHDF2-HRSP12-RNase P/MRP pathway. cFAM210A bound to YBX1 and inhibited its phosphorylation, suppressing its transactivation function toward MET. These findings suggest the important role of circular RNAs in HBx-induced hepatocarcinogenesis and identify cFAM210A a potential target in the prevention and treatment of HBV-related HCC.
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