Identification and expression analysis of the aldo-ketoreductase1-B10 gene in primary malignant liver tumours.
OBJECTIVE
The aim of our study was to search for highly up-regulated genes in primary malignant liver tumours and to analyse their expression at the mRNA- and protein level.


METHODS
Using a random-based gene fishing approach (representational difference analysis coupled to array hybridisation) we identified 7 genes high abundantly expressed in hepatocellular carcinoma (HCC) as compared to non-neoplastic liver tissue, among them a gene fragment of the aldo-ketoreductase (AKR) superfamily. Full length cloning and sequencing of the gene fragment identified it as B10 gene of the AKR-family 1 (AKR1B10). For expression analysis on transcriptional level quantitative real-time RT-PCR was performed in 22 HCC and 22 non-neoplastic liver cirrhotic tissues.


RESULTS
Our data demonstrate significantly higher expression levels of AKR1B10-mRNA in HCC compared to non-tumourous cirrhotic liver tissue (p<0.0001). To evaluate its protein expression in primary malignant liver tumours, we investigated tissue arrays of 210 HCC and 51 cholangiocarcinomas (CC) by immunohistochemistry, using a monoclonal antibody against AKR1B10. Protein staining of AKR1B10 was significantly increased in well and moderately differentiated tumours compared to corresponding non-neoplastic liver tissue (p=0.023). However, AKR1B10-staining decreased in advanced, low differentiated tumours with a significant inverse correlation between AKR1B10-staining and tumour proliferation, indicated by Ki67 (MIB-1) staining (r=-0.89, p=0.02).


CONCLUSIONS
The over-expression of AKR1B10 in early stages of well and moderately differentiated tumours and its down-regulation in advanced tumour-stages with low grade of differentiation demonstrated that AKR1B10 may be a helpful marker for differentiation and proliferation of HCC and CC.
Heringlake
Stefan
S
Department of Gastroenterology, Ruhr-University Bochum, Knappschaftskrankenhaus, In der Schornau 23-25, Bochum, Germany. stefan.heringlake@rub.de
Hofdmann
Michael
M
Fiebeler
Anette
A
Manns
Michael P
MP
Schmiegel
Wolff
W
Tannapfel
Andrea
A
D000449:Aldehyde Reductase / Q000235:genetics* / Q000378:metabolism; D000074408:Aldo-Keto Reductases; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D002454:Cell Differentiation; D049109:Cell Proliferation; D018281:Cholangiocarcinoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D017931:DNA Primers / Q000235:genetics; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D008103:Liver Cirrhosis / Q000201:enzymology / Q000235:genetics; D008113:Liver Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D009367:Neoplasm Staging; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D017931:DNA Primers; D012333:RNA, Messenger; D012334:RNA, Neoplasm; C120471:AKR1B10 protein, human; D000074408:Aldo-Keto Reductases; D000449:Aldehyde Reductase