Correlation of microRNA-16, microRNA-21 and microRNA-101 expression with cyclooxygenase-2 expression and angiogenic factors in cirrhotic and noncirrhotic human hepatocellular carcinoma.
BACKGROUND
Hepatocellular carcinoma (HCC) is a classical example of inflammation-linked cancer and is characterized by hypervascularity suggesting rich angiogenesis. Cycloxygenase-2 (COX-2) is a potent mediator of inflammation and is considered to upregulate angiogenesis. The aims of the study are (1) to analyze expression of Cox-2 mRNA, Cox-2 protein, miR-16, miR-21 and miR-101 in HCC and adjacent liver parenchyma in cirrhotic and noncirrhotic liver, (2) to investigate the relation between COX-2 expression, miR-21 expression and angiogenic factors in these tissues and (3) to investigate the association between miR-16 and miR-101 and COX-2 expression.


METHODS
Tissue samples of HCC and adjacent liver parenchyma of 21 noncirrhotic livers and 20 cirrhotic livers were analyzed for COX-2 expression at the mRNA level (qRT-PCR) and at the protein level by Western blot and immunohistochemistry. Gene expression of VEGFA, VEGFR1, VEGFR2, Ang-1, Ang-2 and Tie-2 were correlated with COX-2 levels. miR-16, miR-21 and miR-101 gene expression levels were quantified in HCC tumor tissue.


RESULTS
COX-2 mRNA and protein levels were lower in HCC as compared to adjacent liver parenchyma both in cirrhotic and noncirrhotic liver. COX-2 protein localized mainly in vascular and sinusoidal endothelial cells and in Kupffer cells. At the mRNA level but not at the protein level, COX-2 correlated with mRNA levels of angiogenic factors VEGFR1, Ang-1, and Tie2. miR-21 expression was higher in cirrhotic tissues versus noncirrhotic tissues. MiR-101 expression was lower in cirrhotic versus noncirrhotic adjacent liver parenchyma. None of the miRNAs correlelated with COX-2 expression. miR-21 correlated negatively with Tie-2 receptor in adjacent liver parenchyma.


CONCLUSIONS
In human HCC, COX-2 mRNA but not COX-2 protein levels are associated with expression levels of angiogenic factors. MiR-21 levels are not associated with angiogenic molecules. MiR-16 and miR-101 levels do not correlate with COX-2 mRNA and protein levels.
Department of Pathology & Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Wenjiao
W
Zeng
Department of Pathology & Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Anke
A
van den Berg
Department of Pathology & Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Sippie
S
Huitema
Department of Pathology & Medical Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Annette S H
AS
Gouw
Department of Pathology & Medical Biology. Medical Biology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Grietje
G
Molema
Department of Hepato-Pancreato-Biliary Surgery & Liver Transplantation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
Koert P
KP
de Jong
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008103:Liver Cirrhosis / Q000235:genetics / Q000378:metabolism*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged
C534072:MIRN101 microRNA, human; C505362:MIRN16 microRNA, human; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human