S. Gao 1 , D. Xi 1 , J.W. Guo 1 , C.L. Zhu 1 , X.P. Luo 2 , Q. Ning 1 1 Department of Infectious Disease, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 2 Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science Objective: This study was designed to explore the opportunity of microRNA interference technique in the inhibitory application of human fgl2, human Fas and TNFR1 expression. Methods: The eukaryotic expression plasmids of human fgl2, Fas and TNFRI genes were constructed and have successfully expressed hfgl2, hFas and hTNFRI protein. miRNA expression plasmids of hfgl2, hFas and hTNFRI complimentary to the sequence responsible for hfgl2, hFas and hTNFRI respectively were also constructed, meanwhile an irrelevant miRNA plasmid was used as control. By respective cotransfection of p-hfgl2miRNA and pcDNA3.1-hfgl2, p-hFasmiRNA and pcDNA3.0-hFas, p-hTNFRI miRNA and pcDNA3.0-hTNFRI expression construct into 293T cells, the inhibition of hfgl2, hFas and hTNFRI expression were analyzed by quatitative real time PCR and western blot. Results: The experiments showed the significantly inhibitory effect of p-hfgl2miRNA on hfgl2, p-hFasmiRNA on hFas and p-hTNFRI miRNA on hTNFRI expression at 48h post-transfection both at RNA level and at protein level, as well in 293T cell lines the inhibitory efficiency reached as high as 89.3% for hfgl2, 87.5% for hFas and 80% for hTNFRI, respectively. Conclusions: The study demonstrated the constructs of p-hfgl2miRNA, p-hFasmiRNA and p-hTNFRI miRNA successfully interfered their target genes expression in vitro, which provides the foundation for further investigation of these constructs' application in vivo and further more as a therapeutic strategy for a targeting intervention in the diseases which the gene fgl2, Fas and TNFRI contribute to. This work was supported by NSFC30571643, 30672380, 30700702; 2005CB522901, 2007CB512900 PE418 Influence of the ID2 on the Anti-Tumor Activity of Histone Deacetylase Inhibitor in Hepatocellular Carcinoma Cells R. Tsunedomi 1,2 , S. Harada 1 , N. Iizuka 1 , M. Oka 1 1 Dept. of Digestive Surgery and Surgical Oncol., Yamaguchi Univ. , 2 Research Fellow of the Japan Society for the Promotion of Science for Young Scientists Background: Our recent study revealed that levels of the Inhibitor of DNA binding/differentiation 2 (ID2) were associated with the progression of HCV-related hepatocellular carcinoma (HCC) and can affect susceptibility of HCC cells to histone deacetylase (HDAC) inhibitors. We here aimed to investigate how and whether ID2 expression affected on the anti-tumor activity of sodium butyrate (NaB), one of HDAC inhibitors. Methods: Two HCC cell lines, HLE and HuH-7, were used for gene targeting experiments. The ID2 over-expressing and knockdown cells were subjected to MTS assay to evaluate the susceptibility to NaB. Time-course of the expressional change of Bcl-2 and Bcl-xL genes after NaB administration was measured by real-time RT-PCR. Result: Upregulation and downregulation of ID2 levels in HCC cells resulted in decreased and increased susceptibility to NaB, respectively. We observed that after NaB administration, the ID2 expression was induced gently, the Bcl-2 expression was greatly increased immediately, and the Bcl-xL expression was decreased to less than half once and then recovered. These increase and recovery of the expression of anti-apoptotic genes were inhibited in the ID2 knockdown cells. In the ID2 overexpressing cells, the Bcl-2 expression was more upregulated than mock-transfected cells.