CRNDE-h transcript/miR-136-5p axis regulates interleukin enhancer binding factor 2 expression to promote hepatocellular carcinoma cell proliferation.

AIMS: Hepatocellular carcinoma (HCC) is a primary malignancy of the hepatocyte. Interleukin enhancer binding factor 2 (ILF2) plays a role in the development of HCC. However, the regulatory mechanisms of ILF2 expression in HCC remain unclear. In this study, we aimed to identify ILF2-targeting microRNAs (miRNAs) and to explore how they affect ILF2 expression in HCC. MAIN METHODS: The tissue specimens were collected from 25 HCC patients. The underlying regulatory mechanism of ILF2 expression in HCC progression was determined using luciferase reporter assay, quantitative real-time PCR, Western blotting, and BrdU incorporation assay. KEY FINDINGS: Of predicted miRNA candidates (miR-122-5p, miR-425-5p, miR-136-5p, miR-7-5p, miR-421 and miR-543), a statistically significant inverse correlation by linear correlation analysis was observed between miR-136-5p and ILF2 mRNA expressions in patients with HCC (r = -0.627, P < 0.001). Further analysis demonstrated that ILF2 was directly regulated by miR-136-5p. In addition, we showed that long noncoding RNA colorectal neoplasia differentially expressed-h (lncRNA CRNDE-h) transcript expression was significantly up-regulated in HCC, and a miR-136-5p binding site was newly found in the lncRNA CRNDE-h transcript sequence using IntaRNA tool. In terms of mechanism, highly-expressed lncRNA CRNDE-h transcript can sponge miR-136-5p, thereby preventing it from interacting with target ILF2 mRNA while promoting the proliferation of HCC cells. SIGNIFICANCE: The lncRNA CRNDE-h/miR-136-5p/ILF2 axis plays a significant regulatory role in HCC progression, which may partly explain the pathogenic mechanisms of HCC and may provide promising potential targets for the diagnosis, treatment, and prognosis of HCC.

Correction: Hepatitis C Virus Core Protein Down-Regulates p21Waf1/Cip1 and Inhibits Curcumin-Induced Apoptosis through MicroRNA-345 Targeting in Human Hepatoma Cells.

[This corrects the article DOI: 10.1371/journal.pone.0061089.].

HCV core inhibits hepatocellular carcinoma cell replicative senescence through downregulating microRNA-138 expression.

Hepatitis C virus (HCV) infection is a major cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). HCV core protein is considered as a positive regulator of telomerase activity. In this study, we focused on the deregulated microRNA-138 (miR-138) in HCV-associated HCC. Differential expression of miR-138 was determined by TaqMan quantitative real-time PCR. The target gene of miR-138 was verified by luciferase reporter assay, quantitative real-time PCR, and Western blotting. Moreover, three assays based on telomerase activity, cell proliferation, and senescence-associated ß-galactosidase activity were performed. The correlation analysis revealed a significantly negative correlation between miR-138 and telomerase reverse transcriptase (TERT) mRNA expression in HCC. Further, we showed that mature HCV core protein of 173 amino acids, but not full-length form of 191 amino acids, suppressed miR-138 expression. TERT was verified as a direct target of miR-138 in HCC cells. Furthermore, TERT-targeting miR-138 supplementation can prevent HCV core protein from repressing HCC cell replicative senescence. Collectively, HCV core protein can enhance TERT protein expression through downregulating TERT-targeting miR-138 expression, which in turn inhibits HCC cell replicative senescence. This study may further help our understanding on the pathogenic mechanisms of HCV core protein in HCV-associated HCC development. KEY MESSAGE: miR-138 is downregulated in HCV-associated HCC. Mature HCV core protein plays a pathogenic role in suppressing miR-138 expression. Telomerase reverse transcriptase represents a direct target of miR-138 in HCC cells. miR-138 promotes HCC cell senescence, suggesting potential for HCC treatment.

Restriction fragment length polymorphism effectively identifies exon 1 mutation of UGT1A1 gene in patients with Gilbert's Syndrome.

BACKGROUND & AIMS: Gilbert's syndrome causes pharmacological variation in drug glucuronidation and unexpected toxicity from therapeutic agents. The two common genotypes of Gilbert's syndrome are a dinucleotide polymorphism (TA)7 in TATA-Box as well as the 211G>A mutation in the coding exon 1, particularly in Asians, of human UGT1A1 gene. In this study, we aimed to establish an effective method to detect the 211G>A mutation. METHODS: The coding exon 1 sequence of human UGT1A1 gene was analysed by Vector NTI software. The 211G>A mutation in the coding exon 1 of UGT1A1 gene was determined by restriction fragment length polymorphism (RFLP) method. Serum total bilirubin level was measured as well. RESULTS: A newly identified BsmBI site was located in the coding exon 1 of UGT1A1 gene. The 211G>A mutation in the coding exon 1 of UGT1A1 gene was determined by DNA RFLP. Furthermore, we reported our present work on genetic analysis of mutations of UGT1A1 gene, and the correlation of UGT1A1 mutations with serum total bilirubin levels in Taiwanese population. The results showed that 15 subjects carried 211G>A mutation in 23 subjects related with Gilbert's syndrome. The homozygous 211G>A mutant as well as simultaneously heterozygous mutants both in TATA-Box and 211G>A significantly increased the risk of Gilbert's syndrome similar to subjects carrying homozygous TATA-Box mutant. CONCLUSIONS: BsmBI RFLP is an effective method to detect 211G>A mutation in the coding exon 1 of UGT1A1 gene. The common 211G>A mutation is one of the causes of Gilbert's syndrome in Taiwanese population.

Hepatitis C virus core protein down-regulates p21(Waf1/Cip1) and inhibits curcumin-induced apoptosis through microRNA-345 targeting in human hepatoma cells.

BACKGROUND: Hepatitis C virus (HCV) has been reported to regulate cellular microRNAs. The HCV core protein is considered to be a potential oncoprotein in HCV-related hepatocellular carcinoma, but HCV core-modulated cellular microRNAs are unknown. The HCV core protein regulates p21(Waf1/Cip1) expression. However, the mechanism of HCV core-associated p21(Waf1/Cip1) regulation remains to be further clarified. Therefore, we attempted to determine whether HCV core-modulated cellular microRNAs play an important role in regulating p21(Waf1/Cip1) expression in human hepatoma cells. METHODS: Cellular microRNA profiling was investigated in core-overexpressing hepatoma cells using TaqMan low density array. Array data were further confirmed by TaqMan real-time qPCR for single microRNA in core-overexpressing and full-length HCV replicon-expressing cells. The target gene of microRNA was examined by reporter assay. The gene expression was determined by real-time qPCR and Western blotting. Apoptosis was examined by annexin V-FITC apoptosis assay. Cell cycle analysis was performed by propidium iodide staining. Cell proliferation was analyzed by MTT assay. RESULTS: HCV core protein up- or down-regulated some cellular microRNAs in Huh7 cells. HCV core-induced microRNA-345 suppressed p21(Waf1/Cip1) gene expression through targeting its 3' untranslated region in human hepatoma cells. Moreover, the core protein inhibited curcumin-induced apoptosis through p21(Waf1/Cip1)-targeting microRNA-345 in Huh7 cells. CONCLUSION AND SIGNIFICANCE: HCV core protein enhances the expression of microRNA-345 which then down-regulates p21(Waf1/Cip1) expression. It is the first time that HCV core protein has ever been shown to suppress p21(Waf1/Cip1) gene expression through miR-345 targeting.

Nuclear factor κB down-regulates human UDP-glucuronosyltransferase 1A1: a novel mechanism involved in inflammation-associated hyperbilirubinaemia.

Jaundice or hyperbilirubinaemia is a common complication of sepsis. UGT1A1 (UDP-glucuronosyltransferase 1A1) is a critical gene for bilirubin metabolism and irinotecan detoxification. However, the molecular pathogenesis of hyperbilirubinaemia during inflammation needs to be further clarified. Human hepatic UGT1A1 expression was analysed by RT (reverse transcription)-PCR, qRT-PCR (quantitative real-time PCR) and Western blotting in response to LPS (lipopolysaccharide) stimulation. Transcription regulatory elements in the upstream promoter region of the human UGT1A1 gene were determined using EMSA (electrophoretic mobility-shift assay) and ChIP (chromatin immunoprecipitation). The important role of the transcription regulatory element was examined using a luciferase assay, and was determined by qRT-PCR using a transcription factor activation inhibitor. LPS down-regulated the UGT1A1 mRNA expression in human hepatoma cell lines. A newly identified NF-κB (nuclear factor κB)-binding site was located on the upstream promoter region (-725/-716) of the human UGT1A1 gene. LPS-induced NF-κB activation and specific binding to the NF-κB-binding site can suppress human UGT1A1 promoter activity and human UGT1A1 expression. We demonstrated that LPS mediates the suppression of human UGT1A1 expression through specific binding of NF-κB to this newly identified NF-κB-binding site in the upstream promoter of the human UGT1A1 gene. The present study may partly explain the molecular pathogenesis of inflammation-associated hyperbilirubinaemia.

Molecular pathogenesis of Gilbert's syndrome: decreased TATA-binding protein binding affinity of UGT1A1 gene promoter.

OBJECTIVES: Gilbert's syndrome is a congenital, nonhemolytic, unconjugated hyperbilirubinemia. The most common genotype of Gilbert's syndrome is the homozygous polymorphism, A(TA)7TAA, in the promoter of the gene for UDP-glucuronosyltransferase 1A1 (UGT1A1), with a thymine adenine insertion in the TATA-box-like sequence, which results in a decrease in UGT1A1 activity. The mechanism responsible for this decrease in UGT1A1 activity, however, has not been elucidated. To clarify the mechanism underlying this deficiency in UGT1A1 activity in patients with Gilbert's syndrome. METHODS: The promoter activity assay using the wild-type A(TA)6TAA or the mutant A(TA)7TAA promoter and a luciferase reporter was performed in two different hepatoma cell lines. The binding affinity for a nuclear protein complex or for TATA-binding protein was evaluated by a competitive electophoretic mobility shift assay using wild-type or mutant TATA-box-like oligonucleotide probes and nuclear extract or TATA-binding protein. The formation of complexes between TATA-binding protein and wild-type or mutant oligonucleotide probes was also studied by a quantitive electophoretic mobility shift assay. RESULTS: A TA insertion in the TATA-box-like sequence of the promoter activity of UGT1A1 gene. A competitive electrophoretic mobility shift assay showed a decrease in nuclear protein complex binding affinity and TATA-binding protein binding affinity of the mutant TATA-box-like sequence A(TA)7TAA. When the mutants A(TA)5TAA and A(TA)8TAA were also compared, quantitative electrophoretic mobility shift assay demonstrated that the TATA-binding protein binding affinity progressively decreased as the number of TA repeats in the TATA-box-like sequence increased. CONCLUSION: TA insertion in the TATA-box-like sequence of the UGT1A1 promoter affected its binding affinity for TATA-binding protein, causing a decrease in its activity. This explains the pathogenesis of Gilbert's syndrome.