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Gastroenterology. 2007 Aug;133(2):647-58. Epub 2007 May 21.

MicroRNA-21 regulates expression of the PTEN tumor suppressor gene in human hepatocellular cancer.

Author information

1
Department of Internal Medicine, Scott and White Clinic, Texas A&M University System Health Science Center College of Medicine, Temple, Texas, USA.

Abstract

BACKGROUND AND AIMS:

microRNAs (miRNAs) are short noncoding RNAs that regulate gene expression negatively. Although a role for aberrant miRNA expression in cancer has been postulated, the pathophysiologic role and relevance of aberrantly expressed miRNA to tumor biology has not been established.

METHODS:

We evaluated the expression of miRNA in human hepatocellular cancer (HCC) by expression profiling, and defined a target gene and biologically functional effect of an up-regulated miRNA.

RESULTS:

miR-21 was noted to be highly overexpressed in HCC tumors and cell lines in expression profiling studies using a miRNA microarray. Inhibition of miR-21 in cultured HCC cells increased expression of the phosphatase and tensin homolog (PTEN) tumor suppressor, and decreased tumor cell proliferation, migration, and invasion. In contrast-enhanced miR-21 expression by transfection with precursor miR-21 increased tumor cell proliferation, migration, and invasion. Moreover, an increase in cell migration was observed in normal human hepatocytes transfected with precursor miR-21. PTEN was shown to be a direct target of miR-21, and to contribute to miR-21 effects on cell invasion. Modulation of miR-21 altered focal adhesion kinase phosphorylation and expression of matrix metalloproteases 2 and 9, both downstream mediators of PTEN involved in cell migration and invasion.

CONCLUSIONS:

Aberrant expression of miR-21 can contribute to HCC growth and spread by modulating PTEN expression and PTEN-dependent pathways involved in mediating phenotypic characteristics of cancer cells such as cell growth, migration, and invasion.

PMID:
17681183
PMCID:
PMC4285346
DOI:
10.1053/j.gastro.2007.05.022
[Indexed for MEDLINE]
Free PMC Article

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