MicroRNA-223 is commonly repressed in hepatocellular carcinoma and potentiates expression of Stathmin1.
OBJECTIVE
Recent studies have emphasized causative links between microRNA (miRNA) deregulations and cancer development. In hepatocellular carcinoma (HCC), information on differentially expressed miRNA remained largely undefined.


METHODS
Array-based miRNA profiling was performed on HCC cells that were derived from chronic carriers of hepatitis B virus (HBV) and hepatitis C virus (HCV), and nonviral-associated patients. Specific microRNA (miR)-223 and miR-222 deregulations were verified in an independent series of tumors. The functional effect of miR-223 was examined further. An integrative analysis of messenger RNA (mRNA) array with in silico predictions defined potential downstream targets of miR-223. A luciferase reporter assay was conducted to confirm target association.


RESULTS
Distinct up-regulations of miR-222, miR-221, and miR-31, and down-regulations of miR-223, miR-126, and miR-122a were identified. Further investigations suggested the highly deregulated miR-223 and miR-222 could unequivocally distinguish HCC from adjacent nontumoral liver, irrespective of viral associations (P <or= .0002). Re-expression of miR-223 in HBV, HCV, and non-HBV non-HCV-related HCC cell lines revealed a consistent inhibitory effect on cell viability (P < .01). Integrative analysis further implicated Stathmin 1 (STMN1) as a downstream target of miR-223. A strong inverse relationship between STMN1 mRNA and miR-223 expressions was shown (P = .006). A substantial reduction in STMN1 protein was further demonstrated upon restoration of miR-223 expression in HCC cell lines. We further showed that miR-223 readily could suppress the luciferase activity in reporter construct containing the STMN1 3' untranslated region (P = .02).


CONCLUSIONS
Our study revealed specific miRNA differential expressions in HCC and underscores the potential importance of miR-223 down-regulations in the development of HCC.
Department of Anatomical and Cellular Pathology at the Li Ka-Shing Institute of Health Sciences, The Chinese University of Hong Kong, SAR Hong Kong, China.
Queenie W-L
QW
Wong
Raymond W-M
RW
Lung
Priscilla T-Y
PT
Law
Paul B-S
PB
Lai
Kathy Y-Y
KY
Chan
Ka-Fai
KF
To
Nathalie
N
Wong
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000821:virology; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D019694:Hepatitis B, Chronic / Q000150:complications; D019698:Hepatitis C, Chronic / Q000150:complications; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000821:virology; D008156:Luciferases / Q000235:genetics; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D050777:Stathmin / Q000235:genetics*
D008156:Luciferases; D035683:MicroRNAs; D050777:Stathmin; C525710:MIR222, human; C525067:MIR223, human; C493995:STMN1 protein, human