Takahiro Kishikawa

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Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. Although novel drugs against HCV are under development, the current standard therapy consists principally of interferon (IFN). To improve the response to IFN treatment by enhancing interferon-stimulated response element (ISRE)-mediated gene transcription, we screened 75(More)
α-fetoprotein (AFP) is not only a widely used biomarker in hepatocellular carcinoma (HCC) surveillance, but is also clinically recognized as linked with aggressive tumour behaviour. Here we show that deregulation of microRNA122, a liver-specific microRNA, is a cause of both AFP elevation and a more biologically aggressive phenotype in HCC. We identify CUX1,(More)
Polyphenols are representative bioactive substances with diverse biological effects. Here, we show that apigenin, a flavonoid, has suppressive effects on microRNA (miRNA) function. The effects were mediated by impaired maturation of a subset of miRNAs, probably through inhibition of the phosphorylation of TRBP, a component of miRNA-generating complexes via(More)
MicroRNAs (miRNAs) are important regulators of gene expression that control physiological and pathological processes. A global reduction in miRNA abundance and function is a general trait of human cancers, playing a causal role in the transformed phenotype. Here, we sought to newly identify genes involved in the regulation of miRNA function by performing a(More)
Despite recent progress in the development of direct-acting antivirals against hepatitis C virus (HCV), chronic HCV infection remains an important health burden worldwide. MicroRNA122 (miR122), a liver-specific microRNA (miRNA), positively regulates HCV replication, and systemic application of antisense oligonucleotides against miR122 led to the(More)
Hepatocellular carcinoma is the third leading cause of cancer mortality worldwide, but the molecular mechanisms in tumorigenesis remain largely unknown. Previously, a DEAD-box protein DDX20, a component of microRNA-containing ribonucleoprotein complexes, was identified as a liver tumor suppressor candidate in an oncogenomics-based in vivo RNAi screen.(More)
Reduced expression of microRNA122 (miR122), a liver-specific microRNA, is frequent in hepatocellular carcinoma (HCC). However, its biological significances remain poorly understood. Because deregulated amino acid levels in cancers can affect their biological behavior, we determined the amino acid levels in miR122-silenced mouse liver tissues, in which(More)
Hepatocellular carcinoma (HCC) is a threat to public health worldwide. We previously identified the association of a single nucleotide polymorphism (SNP) at the promoter region of the MHC class I polypeptide-related sequence A (MICA) gene with the risk of hepatitis-virus-related HCC. Because this SNP affects MICA expression levels, regulating MICA(More)
Nuclear factor κB (NF-κB) is a transcription factor that regulates a set of genes that are critical to many biological phenomena, including liver tumorigenesis. To identify microRNAs (miRNAs) that regulate NF-κB activity in the liver, we screened 60 miRNAs expressed in hepatocytes for their ability to modulate NF-κB activity. We found that miRNA-22 and(More)
UNLABELLED MicroRNAs (miRNAs) are small RNAs that regulate the expression of specific target genes. While deregulated miRNA expression levels have been detected in many tumors, whether miRNA functional impairment is also involved in carcinogenesis remains unknown. We investigated whether deregulation of miRNA machinery components and subsequent functional(More)