The FAT10 gene encodes a diubiquitin-like protein containing two tandem head-to-tail ubiquitin-like domains. There is a high degree of similarity between murine and human FAT10 sequences at both the mRNA and protein levels. In various cell lines, FAT10 expression was shown to be induced by gamma interferon or by tumor necrosis factor alpha. In addition, FAT10 expression was found to be up-regulated in some Epstein-Barr virus-infected B-cell lines, in activated dendritic cells, and in several epithelial tumors. However, forced expression of FAT10 in cultured cells was also found to produce apoptotic cell death. Overall, these findings suggest that FAT10 may modulate cellular growth or cellular viability. Here we describe the steps to generate, by genetic targeting, a FAT10 gene knockout mouse model. The FAT10 knockout homozygous mice are viable and fertile. No gross lesions or obvious histological differences were found in these mutated mice. Examination of lymphocyte populations from spleen, thymus, and bone marrow did not reveal any abnormalities. However, flow cytometry analysis demonstrated that the lymphocytes of FAT10 knockout mice were, on average, more prone to spontaneous apoptotic death. Physiologically, these mice demonstrated a high level of sensitivity toward endotoxin challenge. These findings indicate that FAT10 may function as a survival factor.

E-cadherin is important in cell-to-cell adhesion and controls cell polarity and tissue morphology. Loss of E-cadherin expression occurs in various human tumors and is the first step in cancer invasion and metastasis. We demonstrate that the exogenous expression of E-cadherin transfected into G-415 GB cells not only increases cell-to-cell adhesion but also reduces in vitro cell proliferation, motility and invasion. Our aim was to determine what genes are most affected by the exogenous expression of E-cadherin in GB cancer cells. We analyzed gene expression pertaining to cell proliferation, motility and invasion. Conventional RT-PCR was performed for these genes; quantitative RT-PCR was carried out on genes exhibiting altered expression. Conventional RT-PCR revealed that E-cadherin transfection suppressed expression of mts1 mRNA and increased that of c-myc and MT1-MMP. In quantitative RT-PCR analysis, levels of c-myc and MT1-MMP mRNA were elevated by to 2.56-and 2.22-fold, respectively, in the E-cadherin transfectant, whereas mts-1 was 7.14-fold suppressed compared to parental cells. These results indicated that expression of mts1 mRNA was most affected by E-cadherin transfection. Immunocytochemical analysis of transfectant and parental cells demonstrated an inverse correlation in E-cadherin and mts1 expression. Immunohistochemical analysis of 37 GB cancer specimens confirmed this observation in vivo. Loss of E-cadherin expression followed by expression of the mts1 gene may be an important event for increasing cell proliferation, motility and invasion activity in the progression of GB cancer. © 2002 Wiley-Liss, Inc. Key words: E-cadherin; transfection; quantitative PCR; mts1E-cadherin is a 120 kDa transmembrane glycoprotein expressed on the surface of epithelial cells. In epithelial tissues, E-cadherin mediates homophilic, Ca 2ϩ -dependent intercellular adhesion, which is essential for the maintenance of normal tissue architecture. 1 Loss of E-cadherin expression occurs in a variety of human tumors and is hypothesized to be an important step in the progression from tumor formation to invasion and metastasis. 2 In several cancers, including those of the breast, lung, nasopharynx, bladder, stomach, esophagus and GB, loss of E-cadherin expression has been associated with an unfavorable prognosis 3-6 and shown to accelerate tumorigenesis and tumor progression. 7-9 Indeed, restoration of E-cadherin into cancer cells results in decreased invasiveness, 10 growth suppression 11 and terminal differentiation. 12 The precise mechanism of the E-cadherin suppressive effect on tumor growth or invasion is not known. 13,14 GB carcinoma is a relatively rare but has a poor prognosis as anatomic factors promote fast spread from the primary site. Most large studies of GB carcinoma have demonstrated overall 5-year survival rates of only 5-15%. 15,16 Previous studies have reported that genetic abnormalities in biliary tract carcinoma occurred primarily as dominant oncogene K-ras mutations [17][18][19] and in the tumor-suppressor genes ...

S4a + 5 combined with BDR and D2 lymph node dissection is a highly recommended operation for the treatment of T2 and T3 GB Ca. Further extension of the operation, such as the addition of PD (PpPD) or an extended hepatectomy, should be carefully modified for each individual according to the cancer spread mode.

The hematopoietic system offers many advantages as a model for understanding general aspects of lineage choice and specification. Using oligonucleotide microarrays, we compared gene expression patterns of multiple purified hematopoietic cell populations, including neutrophils, monocytes, macrophages, resting, centrocytic, and centroblastic B lymphocytes, dendritic cells, and hematopoietic stem cells. Some of these cells were studied under both resting and stimulated conditions. We studied the collective behavior of subsets of genes derived from the Biocarta database of functional pathways, hand-tuned groupings of genes into broad functional categories based on the Gene Ontology database, and the metabolic pathways in the Kyoto Encyclopedia of Genes and Genomes database. Principal component analysis revealed strikingly pervasive differences in relative levels of gene expression among cell lineages that involve most of the subsets examined. These results indicate that many processes in these cells behave differently in different lineages. Much of the variation among lineages was captured by the first few principal components. Principal components biplots were found to provide a convenient visual display of the contributions of the various genes within the subsets in lineage discrimination. Moreover, by applying tree-constructing methodologies borrowed from phylogenetics to the expression data from differentiated cells and stem cells, we reconstructed a tree of relationships that resembled the established hematopoietic program of lineage development. Thus, the mRNA expression data implicitly contained information about developmental relationships among cell types.