Novel Differential Gene Expression In Human Cirrhosis And Hepatocellular Carcinoma Associated With Viruses Detected By Representational Difference Analysis

Hepatitis B/C virus (HBV/HCV) are the major etiologic agents of cirrhosis and hepatocellular carcinoma (HCC). In China, HBV chronically infects about 125 million, and HCV infects about 38 million people. Many HBV/HCV carriers usually develop chronic hepatitis(CH), finally complicated with HCC in a liver with cirrhosis or advanced stage CH. Because of interaction between virus and host, dynamic and closely related changes of gene expression are suspected to be involved in the pathogenesis of cirrhosis and hepatocarcinogenesis.To gain insight into virus-host interrelationships and molecular portraits of cirrhosis and HCC, we used a modified complementary DNA representational difference analysis (cDNA-RDA) protocol to compare gene expression between normal liver and HBV cirrhosis, HCV-associated HCC and non-tumorous adjacent tissue. Different products (DP2) were cloned into pGEM-T vector. Positive clones were rescreened for differential expression by dot-blot hybridization with probes from amplicons and DP2. Selected genes were sequenced. Differentially expressed genes included: (1) In cirrhosis glutaminase 1, aldo-keto reductase family 1 B10 (AKR1B10) ,calcium-binding tyrosine phosphorylation regulated protein (CABYR), estrogen responsive B box protein (EBBP) and two expressed sequence tags (EST) homologous with novel genes were up-regulated. CD27 binding protein and nicotinamide N-methyltransferase (NNMT) were down-regulated. (2) In HCC gamma -tubulin, serine dehydratase(SDS), aldosterone synthase(CYPXI2B) and two new genes were up-regulated. The genes associated with xenobiotic catabolism and plasma protein synthesis and tumor associated genes PRSS11.TM-1 were down-regulated. Several differentially expressed genes were confirmed by semi-quantitative RT-PCR in the relevant tissues. CABYR gene were not expressed in normal liver, but expressed in cirrhosis tissue and overexpressed in 7/9 HCC tissues. This result indicates that CABYR gene plays an important role in pathogenesis of liver disease on transcription level. This is the first study that CABYR gene is involved in human disease. PRSS11 and TM-1 show differential expression pattern in 9 HCC tissues.Conclusions: (1) Subtractive EST libraries of cirrhosis and HCC were constructed using modified cDNA-RDA. Novel observations of differential gene expression in liver disease were made. Further studies of CABYR gene and its products are warrented. (2) Combination of RDA and high-through rescreening can isolate differentially expressed genes involved in human disease successfully and obtain more insight into virus-host interaction.