Role of microRNA-155 at early stages of hepatocarcinogenesis induced by choline-deficient and amino acid–defined diet in C57BL/6 mice

Authors

  • Bo Wang,

    1. Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH
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  • Sarmila Majumder,

    1. Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH
    2. Comprehensive Cancer Center, Ohio State University, Columbus, OH
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  • Gerard Nuovo,

    1. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    2. Department of Pathology, Ohio State University, Columbus, OH
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  • Huban Kutay,

    1. Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH
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  • Stefano Volinia,

    1. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    2. Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, OH
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  • Tushar Patel,

    1. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    2. Department of Gastroenterology and Hepatology, Ohio State University, Columbus, OH
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  • Thomas D. Schmittgen,

    1. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    2. Department of Pharmacy and Ohio State University, Columbus, OH
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  • Carlo Croce,

    1. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    2. Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, OH
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  • Kalpana Ghoshal,

    Corresponding author
    1. Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH
    2. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    • 420 West 12th Avenue, Columbus, OH 43210
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    • fax: 614-688-5600

  • Samson T. Jacob

    Corresponding author
    1. Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH
    2. Comprehensive Cancer Center, Ohio State University, Columbus, OH
    • 420 West 12th Avenue, Columbus, OH 43210
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    • fax: 614-688-5600


  • Potential conflict of interest: Nothing to report.

Abstract

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 ≤ 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/EBPβ), respective targets of miR-21 and miR-155, in these mice at early stages. DNA binding activity of nuclear factor kappa B (NF-κB) 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/EBPβ 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. (HEPATOLOGY 2009.)

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