Silencing of microRNA-122 is an early event during hepatocarcinogenesis from non-alcoholic steatohepatitis.
ABSTRACT: Non-alcoholic steatohepatitis (NASH) has emerged as a common cause of chronic liver disease and virus-independent hepatocellular carcinoma (HCC) in patients with obesity, diabetes, and metabolic syndrome. To reveal the molecular mechanism underlying hepatocarcinogenesis from NASH, microRNA (miRNA) expression profiles were analyzed in STAM mice, a NASH-HCC animal model. MicroRNA expression was also examined in 42 clinical samples of HCC tissue. Histopathological images of the liver of STAM mice at the ages of 6, 8, 12, and 18 weeks showed findings compatible with fatty liver, NASH, liver cirrhosis (LC), and HCC, respectively. Expression of miR-122 in non-tumor LC at the age of 18 weeks was significantly lower than that in LC at the age of 12 weeks. Expression of miR-122 was further decreased in HCCs relative to non-tumor LC at the age of 18 weeks. Expression of miR-122 was also decreased in clinical samples of liver tissue showing macrovesicular steatosis and HCC, being consistent with the findings in the NASH model mice. DNA methylation analysis revealed that silencing of miR-122 was not mediated by DNA hypermethylation of the promoter region. These results suggest that silencing of miR-122 is an early event during hepatocarcinogenesis from NASH, and that miR-122 could be a novel molecular marker for evaluating the risk of HCC in patients with NASH.
Project description:The prevalence of hepatocellular carcinoma (HCC) is still high worldwide because liver diseases could develop into HCC. Recent reports indicate nonalcoholic fatty liver disease and nonalcoholic steatohepatitis (NAFLD&NASH) and primary biliary cirrhosis and primary sclerosing cholangitis (PBC&PSC) are significant of HCC. Therefore, understanding the cellular mechanisms of the pathogenesis and hepatocarcinogenesis from normal liver cells to HCC through NAFLD&NASH or PBC&PSC is a priority to prevent the progression of liver damage and reduce the risk of further complications. By the genetic and epigenetic data mining and the system identification through next-generation sequencing data and its corresponding DNA methylation profiles of liver cells in normal, NAFLD&NASH, PBC&PSC, and HCC patients, we identified the genome-wide real genetic and epigenetic networks (GENs) of normal, NAFLD&NASH, PBC&PSC, and HCC patients. In order to get valuable insight into these identified genome-wide GENs, we then applied a principal network projection method to extract the corresponding core GENs for normal liver cells, NAFLD&NASH, PBC&PSC, and HCC. By comparing the signal transduction pathways involved in the identified core GENs, we found that the hepatocarcinogenesis through NAFLD&NASH was induced through DNA methylation of HIST2H2BE, HSPB1, RPL30, and ALDOB and the regulation of miR-21 and miR-122, and the hepatocarcinogenesis through PBC&PSC was induced through DNA methylation of RPL23A, HIST2H2BE, TIMP1, IGF2, RPL30, and ALDOB and the regulation of miR-29a, miR-21, and miR-122. The genetic and epigenetic changes in the pathogenesis and hepatocarcinogenesis potentially serve as potential diagnostic biomarkers and/or therapeutic targets.
Project description:Hepatocellular carcinoma (HCC) is the fastest-rising cause of cancer-related death in the United States. Recent epidemiological studies have identified nonalcoholic steatohepatitis (NASH), a progressive form of nonalcoholic fatty liver disease (NAFLD), as a major risk factor for HCC. Elucidating the underlying mechanisms associated with the development of NASH-derived HCC is critical for identifying early biomarkers for the progression of the disease and for treatment and prevention. In the present study, using liver samples from C57BL/6J mice submitted to the Stelic Animal Model (STAM) of NASH-associated liver carcinogenesis, we investigated the role of microRNA (miRNA) alterations in the pathogenesis of NASH-derived HCC. We found substantial alterations in the expression of miRNAs, with the greatest number occurring in full-fledged HCC. Mechanistically, altered miRNA expression was associated with activation of major hepatocarcinogenesis-related pathways, including the TGF-?, Wnt/?-catenin, ERK1/2, mTOR, and EGF signaling. In addition, the over-expression of the miR-221-3p and miR-222-3p and oncogenic miR-106b?25 cluster was accompanied by the reduced protein levels of their targets, including E2F transcription factor 1 (E2F1), phosphatase and tensin homolog (PTEN), and cyclin-dependent kinase inhibitor 1 (CDKN1A). Importantly, miR-93-5p, miR-221-3p, and miR-222-3p were also significantly over-expressed in human HCC. These findings suggest that aberrant expression of miRNAs may have mechanistic significance in NASH-associated liver carcinogenesis and may serve as an indicator for the development of NASH-derived HCC.
Project description:UNLABELLED:MicroRNAs (miRs) are conserved, small (20-25 nucleotide) noncoding RNAs that negatively regulate expression of messenger RNAs (mRNAs) at the posttranscriptional level. Aberrant expression of certain microRNAs plays a causal role in tumorigenesis. Here, we report identification of hepatic microRNAs that are dysregulated at early stages of feeding C57BL/6 mice choline-deficient and amino acid-defined (CDAA) diet that is known to promote nonalcoholic steatohepatitis (NASH)-induced hepatocarcinogenesis after 84 weeks. Microarray analysis identified 30 hepatic microRNAs that are significantly (P < or = 0.01) altered in mice fed CDAA diet for 6, 18, 32, and 65 weeks compared with those fed choline-sufficient and amino acid-defined (CSAA) diet. Real-time reverse transcription polymerase chain reaction (RT-PCR) analysis demonstrated up-regulation of oncogenic miR-155, miR-221/222, and miR-21 and down-regulation of the most abundant liver-specific miR-122 at early stages of hepatocarcinogenesis. Western blot analysis showed reduced expression of hepatic phosphatase and tensin homolog (PTEN) and CCAAT/enhancer binding protein beta (C/EBPbeta), respective targets of miR-21 and miR-155, in these mice at early stages. DNA binding activity of nuclear factor kappa B (NF-kappaB) that transactivates miR-155 gene was significantly (P = 0.002) elevated in the liver nuclear extract of mice fed CDAA diet. Furthermore, the expression of miR-155, as measured by in situ hybridization and real-time RT-PCR, correlated with diet-induced histopathological changes in the liver. Ectopic expression of miR-155 promoted growth of hepatocellular carcinoma (HCC) cells, whereas its depletion inhibited cell growth. Notably, miR-155 was significantly (P = 0.0004) up-regulated in primary human HCCs with a concomitant decrease (P = 0.02) in C/EBPbeta level compared with matching liver tissues. CONCLUSION:Temporal changes in microRNA profile occur at early stages of CDAA diet-induced hepatocarcinogenesis. Reciprocal regulation of specific oncomirs and their tumor suppressor targets implicate their role in NASH-induced hepatocarcinogenesis and suggest their use in the diagnosis, prognosis, and therapy of liver cancer.
Project description:To uncover mechanisms of nonalcoholic steatohepatitis (NASH) associated hepatocarcinogenesis, we compared the proteomes of human NASH-associated liver biopsies, resected hepatocellular carcinomas (HCCs) and HCCs of HCV? patients with normal liver tissue of patients with gastrointestinal tumor metastasis, in formalin-fixed paraffin-embedded samples obtained after surgery in our hospital during the period from 2006 to 2011. In addition, proteome analysis of liver tumors in male STAM NASH-model mice was performed. Similar changes in the proteome spectrum such as overexpression of enzymes involved in lipid, cholesterol and bile acid biosynthesis and examples associated with suppression of fatty acid oxidation and catabolism, alcohol metabolism, mitochondrial function as well as low expression levels of cytokeratins 8 and 18 were observed in both human NASH biopsies and NASH HCCs, but not HCV? HCCs. Alterations in downstream protein expression pointed to significant activation of transforming growth factor ?, SMAD family member 3, ?-catenin, Nrf2, SREBP-LXR? and nuclear receptor-interacting protein 1 (NRIP1), and inhibition of PPARs and p53 in human NASH biopsies and/or HCCs, suggesting their involvement in accumulation of lipids, development of fibrosis, oxidative stress, cell proliferation and suppression of apoptosis in NASH hepatocarcinogenesis. In STAM mice, PPARs inhibition was not obvious, while expression of cytokeratins 8 and 18 was elevated, indicative of essential differences between human and mouse NASH pathogenesis.
Project description:miR-122 is the most abundant miRNA in the liver particularly in hepatocytes where it targets cholesterol metabolism. Steatosis, a key component of non-alcoholic fatty liver disease, is regulated by hypoxia-inducible factor-1? (HIF-1?). Here, we hypothesized that reduced miR-122 has a pathogenic role in steatohepatitis.miR-122 and its target genes were evaluated in mouse livers and/or isolated hepatocytes after methionine-choline-deficient (MCD) or methionine-choline-supplemented (MCS) diet.Liver and hepatocyte miR-122 expression was significantly decreased in steatohepatitis. A maximum reduction in miR-122 occurred at the fibrosis stage (8 weeks of MCD diet). MAP3K3, a miR-122 target gene, was induced at all stages of non-alcoholic steatohepatitis (NASH; 3-8 weeks) only at the mRNA level. Increased NF-?B activation was found in MCD diet-fed mice and MAP3K3 regulated the NF-?B DNA binding in naive hepatocytes. HIF-1? mRNA and DNA binding and expression of the HIF-1? target gene, profibrotic lysyl oxidase, was increased in advanced steatohepatitis (8 weeks). In addition, increase in vimentin and Sirius red staining (liver fibrosis) was found at 8 weeks of MCD diet. Using miR-122 overexpression and inhibition approaches, we confirmed that HIF-1?, vimentin and MAP3K3 are novel miR-122 targets in hepatocytes. We report transcriptional repression of miR-122 in NASH. Decreased liver miR-122 was associated with elevated circulating miR-122 in both exosome-rich and protein-rich serum fractions.Our novel data suggest that decreased liver miR-122 contributes to upregulation of modulators of tissue remodelling (HIF-1?, vimentin and MAP3K3) and might play a role in NASH-induced liver fibrosis.
Project description:Hepatocellular carcinoma (HCC), which accounts for 90% of all primary livers tumors, is the fourth most common cancer in the world. The development of HCC is a long-term and complex process, and uncovering the molecular mechanisms associated with HCC development is critical for the disease diagnosis, prevention, and treatment. Exploring these mechanisms using human HCC samples is desirable, but frequently impractical, with a number of limitations and shortcomings. The STAMTM (Stelic Institute & Co, Tokyo, Japan) mouse model of NASH-associated liver carcinogenesis is considered a useful and relevant model for investigating the molecular pathogenesis of NASH-derived HCC. This model resembles the human HCC development associated with progression from simple steatosis to NASH, fibrosis, and HCC. In the present study, by using high-throughput whole genome microarrays (SurePrint G3 Mouse Gene Expression v2, 8x60K; Agilent Technologies, Santa Clara, CA), we examined the transcriptomic profiles in the livers of STAMTM mice at different stages of liver carcinogenesis, including steatosis (6 week time interval), NASH (8 weeks), fibrotic stage (12 weeks), and in full-fledged HCC (20 weeks). The results of microarray analyses showed significant progressive changes in hepatic gene expression during the development of HCC. A total of 970, 1462, 2742, and 2857 of differentially expressed genes were identified in the livers at 6, 8, 12, and 20 weeks, respectively. Detailed analysis of these differentially expressed genes will benefit the understanding of the underlying mechanisms of non-alcoholic fatty liver disease-derived HCC. Transcriptomic profile in the liver of STAM mice at 6 weeks (steatosis; n=3), 8 weeks (steatohepatitis; n=3) 12 weeks (fibrosis; n=4) and 20 weeks (HCC-stage tumor tissue, n=4) weeks. Age-matched control samples were also analyzed.
Project description:BACKGROUND:MicroRNA-122 (miR-122), a pivotal liver-specific miRNA, is frequently repressed in hepatocellular carcinoma (HCC) and associated with poor prognosis. Long non-coding RNA (lncRNA) HOTAIR has been proved to function as an oncogene in multiple cancers including HCC. However, the relationship between HOTAIR and miR-122 in HCC remains largely unknown. METHODS:We investigated the function of HOTAIR and miR-122 in HCC cell models and a xenograft mouse model. The regulatory network between HOTAIR and miR-122 was further detected following overexpression or knockdown of HOTAIR. DNA methylation status of miR-122 promoter region, as well as expression levels of DNMTs, EZH2 and Cyclin G1 were analyzed. FINDINGS:In this study, we found that HOTAIR was highly expressed whereas miR-122 was suppressed in HCC, and HOTAIR negatively regulated miR-122 expression in HCC cells. Furthermore, knockdown of HOTAIR dramatically inhibited HCC cell proliferation and induced cell cycle arrest in vitro and suppressed tumorigenicity in vivo by upregulating miR-122 expression. Mechanistically, a CpG island was located in the miR-122 promoter region. HOTAIR epigenetically suppressed miR-122 expression via DNMTs-mediated DNA methylation. Moreover, HOTAIR upregulated DNMTs expression via EZH2. In addition, suppression of miR-122 induced by HOTAIR directly reactivated oncogene Cyclin G1 expression. Collectively, our results suggest that HOTAIR epigenetically suppresses miR-122 expression via DNA methylation, leading to activation of Cyclin G1 and promotion of tumorigenicity in HCC, which provide new insight into the mechanism of HOTAIR-mediated hepatocarcinogenesis via suppressing miR-122.
Project description:Deregulation of microRNAs (miRNAs) is a typical feature of human hepatocellular carcinoma (HCC). However, the in vivo relevance of miRNAs along hepatocarcinogenesis remains largely unknown. Here, we show that liver tumors induced in mice by c-Myc overexpression or AKT/Ras co-expression exhibit distinct miRNA expression profiles. Among the downregulated miRNAs, eight (miR-101, miR-107, miR-122, miR-29, miR-365, miR-375, miR-378, and miR-802) were selected and their tumor suppressor activity was determined by overexpressing each of them together with c-Myc or AKT/Ras oncogenes in mouse livers via hydrodynamic transfection. The tumor suppressor activity of these microRNAs was extremely heterogeneous in c-Myc and AKT/Ras mice: while miR-378 had no tumor suppressor activity, miR-107, mir-122, miR-29, miR-365 and miR-802 exhibited weak to moderate tumor suppressor potential. Noticeably, miR-375 showed limited antineoplastic activity against c-Myc driven tumorigenesis, whereas it strongly inhibited AKT/Ras induced hepatocarcinogenesis. Furthermore, miR-101 significantly suppressed both c-Myc and AKT/Ras liver tumor development. Altogether, the present data demonstrate that different oncogenes induce distinct miRNA patterns, whose modulation differently affects hepatocarcinogenesis depending on the driving oncogenes. Finally, our findings support a strong tumor suppressor activity of miR-101 in liver cancer models regardless of the driver oncogenes involved, thus representing a promising therapeutic target in human HCC.
Project description:miR-122, a completely conserved liver-specific miRNA in vertebrates, is essential for the maintenance of liver homeostasis. This 22 nucleotide RNA regulates diverse functions such as cholesterol, glucose and iron homeostasis, lipid metabolism and infection of hepatitis C virus (HCV) and of the parasitic protozoa, Leishmania donovani. It is the first miRNA that underwent successful clinical trials in HCV infected patients. In contrast, miR-122 expression is reduced in nonalcoholic steatohepatitis (NASH) patients, and in a subset of hepatocellular carcinoma (HCC) patients including hepatitis B virus (HBV) positive patients with highly invasive and metastatic cancer. Studies in mice genetically depleted of miR-122 have highlighted its critical role in liver biology. These mice progressively develop steatohepatitis, fibrosis and hepatocellular cancer, establishing it as a bona fide tumor suppressor. Additionally, delivery of miR-122 using a viral vector or liposomal nanoparticles resulted in liver tumor suppression in animal models. These results suggest miR-122 supplementation might be beneficial in NASH or HBV positive HCC patients. Furthermore, circulating miR-122 has emerged as a sensitive biomarker for liver injury. The ability of miR-122 to promote differentiation of embryonic and adult stem cells to hepatocyte-like cells in vitro suggests its potential role in driving the hepatic differentiation program. In this review, we will discuss the role of miR-122 in liver physiology and the deleterious consequences of its loss of function, its role as a sensitive biomarker for liver injury and therapeutic target. Development of novel technologies for targeted delivery of miR-122 to tumor cells and for direct monitoring of miR-122 in biological fluids is urgently needed for translating the basic research to the bedside. This review focuses on miR-122, the most abundant hepatic miRNA, in the context of liver health and diseases.
Project description:Telomerase reverse-transcriptase (TERT) gene promoter mutations in circulating cell-free DNA (cfDNA) as well as the levels of circulating microRNA-122 (miR-122) have been reported as potential noninvasive biomarkers for several. This study evaluates the diagnostic performance of potent biomarker-based panels composing of serological AFP, miR-122 and circulating TERT promoter mutations for screening HBV-related HCC. TERT promoter mutations (C228T and C250T) and miR-122 expression were assessed in the plasma samples from 249 patients with HBV-related liver diseases by nested PCR and qRT-PCR assays, respectively. The diagnostic values of TERT promoter mutations, miR-122 expression and biomarker-based panels were assessed by computation of the area under the curve (AUC). Nested-PCR assays were optimized to detect C228T and C250T mutations in TERT promoter with detection limit of 1%. The common hotspot C228T was observed in 22 HCC cases. The triple combinatory panel (AFP@TERT@miR-122) acquired the best diagnostic value to distinguish HCC from CHB (AUC?=?0.98), LC (AUC?=?0.88) or non-HCC (LC?+?CHB, AUC?=?0.94) compared to the performance of double combinations or single biomarkers, respectively. Notably, among patients with AFP levels?20?ng/?l, the double combination panel (TERT@miR-122) retains satisfactory diagnostic performance in discriminating HCC from the others (HCC vs. CHB, AUC?=?0.96; HCC vs. LC, AUC?=?0.88, HCC vs. non-HCC, AUC?=?0.94). The triple combination panel AFP@TERT@miR-122 shows a better diagnostic performance for screening HCC in HBV patients, regardless of AFP levels. The newly established panels can be a potential application in clinical practice in Vietnamese setting.