Functional Analysis Of UBF Gene And SVH Gene In Hepatocellular Carcinomas And Expression Profiling Analysis In Human Fetal Livers And Hepatocellular Carcinomas

Hepatocellular carcinoma (HCC) is one of the most common malignant tumorswith poor prognosis, and China is the area with highest HCC risk. Byrepresentational difference analysis (RDA), the genes, which changed theirexpression levels in HCCs, were identified and further studied. In addition, we usedthe cDNA array platform to analyze the expression pattern of HCCs and fetal livers.The molecular mechanisms of carcinogenesis and organogenesis were also compared.The dissertation is focused on these two topics. Chapter One of the dissertation briefly describes how to get the genesup-regulated in HCCs by RDA, and then, describes the functional analysis in one ofthe known genes – UBF (Upstream Binding Factor). Combined with othertechniques, up-regulation of UBF was detected in about 66% (19 of 29) of HCCsamples. Overexpression of UBF in human lung fibroblast cells resulted in anaccelerated rate of cell growth; on the other hand, inhibition of UBF expression inhuman hepatoma cell lines by antisense oligodeoxynucleotides (ODNs) treatment,suppressed the colony formation capacity of these cells on soft agarose, and finally iii中国科学院上海生物化学与细胞生物学研究所 博士学位论文 论文摘要caused cell death. Notably, UBF expression could increase the cell sensitivity to thechemotherapeutic reagent cis-diaminedichloroplatinum (II). We proposed that UBFis fundamental to the cell survival, and it is potential as a target for screeninganti-cancer drugs and an indicator in selecting chemotherapeutic reagents. Chapter Two describes the functional analysis in one of the unknown genesidentified by RDA – SVH gene. We cloned this gene and observed the alternativesplicing in this gene. The four spliced variants were designated SVH-A, -B, -C, and-D, respectively. Up-regulation of SVH-B, but not the other variants, was evident inabout 60% (28 of 46) of HCC samples, detected by quantitative real-time PCR.Human liver cell line QSG-7701 with overexpression of SVH-B, acquired anaccelerated growth rate and tumorigenicity in nude mice, whereas inhibition ofSVH-B in hepatoma cell line BEL-7404, using antisense ODNs, induced apoptosis.It is suggested that the splicing variants of SVH have distinct biological functions,and SVH-B may play an important role in hepatocarcinogenesis. Chapter Three describes the expression profiling analysis of human fetal liversin hematogenesis, normal adult livers and HCCs using cDNA arrays containing 5612gene/clusters. Hierarchical clustering separated these samples into three groups withdistinct physiological-specific patterns: fetal, adult, and HCC. The genes changed inthe same direction during hepatocarcinogenesis and hepatic organogenesis,controlled protein expression and metabolism. However, the genes changed only inone specific process, functioned in cell proliferation, signal transduction and mRNAtranscription. It is indicated that independent transcriptional activation is involved inhepatocarcinogenesis and liver development in hematogenesis.