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O Hino

Publications and source records attributed to O Hino.

At least 73 records · Page 4Linked to original sources
PubMed1998

Generation of metastatic variants of Eker renal carcinoma cell lines for experimental investigation of renal cancer metastasis.

We and others have demonstrated that a mutation in Tsc2 is the rate-limiting step for renal carcinogenesis in the Eker rat model. Although inactivation of Tsc2 results in development of renal tumors, it is not sufficient for metastatic renal cell carcinomas (RCs) in the Eker rat. To investigate the additional genetic event(s) necessary for cancer metastasis, we have established highly metastatic S-Lk9d-SLM cell lines from a non-metastatic RC cell line (Lk9dL) by co-implantation with a foreign body (gelatin sponge). Since these cell lines were remarkably different in metastatic performance (all and none, respectively) despite having the same genetic background, they should be useful experimental tools to investigate metastasis-promoting events in renal carcinogenesis.

Animals↗
PubMed1998

Development of high-grade renal cell carcinomas in rats independently of somatic mutations in the Tsc2 and VHL tumor suppressor genes.

Ferric nitrilotriacetate (Fe-NTA) induces renal proximal tubular damage that ultimately leads to a high incidence of renal cell carcinoma (RCC) in rats. The RCCs are characterized by 1) high incidence of pulmonary metastasis and peritoneal invasion, 2) high incidence of tumor-associated mortality and 3) possible involvement of reactive oxygen species in carcinogenesis. The present study investigated the possible role of Tsc2 and VHL tumor suppressor genes in this model. Thirty-four Fe-NTA-induced primary RCCs and 20 other primary or metastatic tumors of rats were searched for genetic alteration in all the coding exons of both genes by polymerase chain reaction-single-strand-conformation polymorphism analysis and sequencing in conjunction with morphological evaluation. In the Fe-NTA-induced RCCs, frequency of metastasis or invasion was proportionally associated with the nuclear grade of the tumor (grades 1-3). Only one Fe-NTA-induced RCC of grade 1 revealed missense mutations with loss of heterozygosity in exon 10 of the Tsc2 gene (codons 334, GTG (Val) to GCG (Ala), and 336, TAT (Tyr) to CAT (His). No mutation was found in the VHL gene. The results suggest that 1) high-grade RCCs can develop in the absence of mutations in the Tsc2 and VHL genes in rats, and that 2) Tsc2 gene somatic mutation can nonetheless be one of the causes of non-Eker rat RCCs.

Animals↗
PubMed1998

Induction of tumor necrosis factor-alpha mRNA in the kidney of the mouse chronic hepatitis model.

Previously we reported the induction of tumor necrosis factor (TNF)-alpha mRNA in the liver of interferon (IFN)-gamma transgenic mouse, which might be the result of IFN-gamma gene expression. In the present study, IFN-gamma mRNA was induced in the liver, kidney and lung. TNF-alpha mRNA was, however, induced in the liver and kidney, but not in the lung. Induction of interleukin (IL)-2 and IL-1beta mRNA was lacking in any of these organs. The present result showed the induction of TNF-alpha mRNA expression in the kidney of transgenic mouse.

Animals↗
PubMed1998

Induction of Fas ligand and Fas antigen mRNA expressions in interferon-gamma transgenic mouse liver.

The interferon-gamma (IFN-gamma) transgenic mouse develops chronic hepatitis. In the present study, lymphoid cell infiltration and expression of the Fas system were studied in the transgenic mouse liver. Morphological analysis showed the infiltration of lymphoid cells at the portal area and necro-inflammation in the lobules. Furthermore, the infiltrating lymphoid cells were found to be present in the areas of piecemeal necrosis and the intralobular region. The polymerase chain reaction revealed induction of Fas antigen and Fas ligand mRNA expressions. The chronic hepatitis in this mouse reflects the profiles of human chronic hepatitis.

Alanine Transaminase↗
PubMed1998

Specific induction of hepatocellular adenomas by transplacental administration of ENU in the tsc2 gene mutant (Eker) rat.

Eker rats develop dominantly inherited renal carcinomas (RCs), with hereditary mutation, and following somatic mutation (Knudson's second hit) at tuberous sclerosis gene (Tsc2). We document the effect of transplacental administration of N-ethyl-N-nitrosourea to Eker (Eker/+) and non-Eker (+/+) rats (same genetic background). Although we observed no difference in the number of preneoplastic GST-P positive foci between Eker and non-Eker rats, interestingly we observed the specific development of hepatocellular adenomas only in Eker rats. The Tsc2 gene mutation might thus influence the phenotype of preneoplastic initiated hepatocytes.

Adenoma, Liver Cell↗
PubMed1997

Overexpression of members of the AP-1 transcriptional factor family from an early stage of renal carcinogenesis and inhibition of cell growth by AP-1 gene antisense oligonucleotides in the Tsc2 gene mutant (Eker) rat model.

We previously isolated subtracted cDNA clones for genes having increased expression in Tsc2 gene mutant (Eker) rat renal carcinomas (RCs). Among them, fra-1 encoding a transcriptional factor activator protein 1 (AP-1) was identified. We have therefore investigated whether other members of the AP-1 transcription factor family might also be involved in renal carcinogenesis in the Eker rat model. In the present study, overexpression of fra-1, fra-2, c-jun, junB, and junD mRNAs was demonstrated in RCs by Northern blot analysis. Interestingly, AP-1 proteins were highly expressed even in the earliest preneoplastic lesions (e.g., phenotypically altered tubules) as suggested by immunohistochemistry. Moreover, 12-O-tetradecanoylphorbol-13-acetate-responsive element (TRE)-binding activity of AP-1 proteins was observed in RC cell extracts by electrophoretic mobility shift assay. As a next step, we transfected antisense oligonucleotides targeting AP-1 genes into RC cells and demonstrated that their growth was strongly inhibited. Thus, the data suggest that overexpression of AP-1 genes might play a crucial role in renal carcinogenesis in the Eker rat model.

Animals↗
PubMed1997

Evaluation of anti-hepatitis B virus (HBV) drugs using the HBV transgenic mouse: application of the semiquantitative polymerase chain reaction (PCR) for serum HBV DNA to monitor the drug efficacy.

For evaluation of anti-hepatitis B virus (HBV) drugs, we have employed the HBV transgenic mouse in which virion-like particles can be assayed in the serum. Bispivaloyloxymethyl-9-(2-phosphonylmethoxyethyl)-adenine [bis (POM) PMEA] 100 mg/kg/day, 2',3'-dideoxy-3'-thiacytidine [(+-)-BCH189] 200 mg/kg/day and a placebo were orally administered to mice twice a day for 14 days. Anti-viral effects were monitored by checking the levels of serum HBV DNA by the semiquantitative polymerase chain reaction, HBsAg and HBeAg by enzyme immunoassay, and replicative intermediates in the liver by Southern blotting. As expected, decrease from the 10(0.5) to 10(3) copies of HBV DNA per microl of sera detected before the treatment to the undetectable level was evident for all five animals treated with bis(POM) PMEA 100 mg/kg/day. However (+-)-BCH189 200 mg/kg/day, which is known to act as the inhibitor of reverse transcriptase for HBV or HIV in vivo and in vitro, did not suppress HBV DNA levels in the transgenic mouse. Thus, we were able to detect the effects of anti-HBV drugs semi-quantitatively, and confirm differences in drug efficacy.

Adenine↗
PubMed1997

Hyperlipidemia enhancement of renal preneoplasia but not tumor formation is due to elevated apoptosis in the Eker rat.

The influence of a high-fat diet on the appearance of renal tumors was assessed in the Eker rat model of hereditary renal carcinoma. Examination of H&E-stained sections showed a significant increase in the number of microscopic solid adenomas in the high-fat group compared with the low-fat group, whereas there was no significant difference in the number of macroscopic tumors between the two groups. Where had the tumor buds gone? Staining for apoptotic bodies occasionally revealed apoptosis in and around the microscopic adenomas. In addition, an Eker rat renal tumor-derived cell line showed apoptosis when it was cultured with high concentrations of native and acetylated low-density lipoprotein. These findings suggested that tumor buds repeatedly appeared and disappeared in Eker rats on a high-fat diet.

Adenoma↗
PubMed1997

Transgenic rescue from embryonic lethality and renal carcinogenesis in the Eker rat model by introduction of a wild-type Tsc2 gene.

We recently reported that a germ-line insertion in the rat homologue of the human tuberous sclerosis gene (TSC2) gives rise to dominantly inherited cancer in the Eker rat model. In this study, we constructed transgenic Eker rats with introduction of a wild-type Tsc2 gene to ascertain whether suppression of the Eker phenotype is possible. Rescue from embryonic lethality of mutant homozygotes (Eker/Eker) and suppression of N-ethyl-N-nitrosourea-induced renal carcinogenesis in heterozygotes (Eker/+) were both observed, defining the germ-line Tsc2 mutation in the Eker rat as embryonal lethal and tumor predisposing mutation. To the best of our knowledge, this is the first report of rescue from a naturally occurring dominantly inherited cancer. This transgenic rescue system will be useful to analyze Tsc2 gene function, its relation to tumorigenesis in vivo, and genetic-environmental interactions in carcinogenesis.

Animals↗
PubMed1997

Identification of a leader exon and a core promoter for the rat tuberous sclerosis 2 (Tsc2) gene and structural comparison with the human homolog.

Hereditary renal carcinoma in the Eker rat is an excellent example of predisposition to a specific cancer being transmitted as a dominant trait. Recently, we identified a germline mutation of the tuberous sclerosis 2 (Tsc2) gene in the Eker rat. In the present study, we analyzed the upstream region of the Tsc2 gene. A novel leader exon (exon 1a) in a CpG island was found, and core promoter activity was identified in a 242-bp region of this island. Exon 1a and the promoter region were conserved in the human TSC2 gene. In addition, a rat homolog of a gene found upstream of TSC2 in human has been identified, indicating that the genomic organization around Tsc2/TSC2 is conserved between the two species. Characterization of the 5' region of Tsc2 and TSC2 will facilitate studies of the regulation of the gene and its disregulation in tumorigenesis.

Animals↗
PubMed1997

Somatic mutation of the tuberous sclerosis (Tsc2) tumor suppressor gene in chemically induced rat renal carcinoma cell.

PURPOSE: von Hippel-Lindau (VHL) gene mutations are detected in noninherited, sporadic human renal cell carcinomas (RCs) at a high frequency. We recently identified a germline mutation in the rat homologue of the human tuberous sclerosis (TSC2) predisposing RC gene in the Eker rat model, and in this study we searched for mutations of the Tsc2 gene in chemically induced non-Eker rat RCs. MATERIALS AND METHODS: Chemically [N-ethyl-N-hydroxyethylnitrosamine (EHEN)]-induced non-Eker rat RC lines (designated as BP13 and BP36B) were subjected to PCR-single strand conformation polymorphism (PCR-SSCP) analysis using specific primers covering entire exons of Tsc2 gene (41 coding exons and one non-coding exon). We simultaneously searched for mutations of Vhl gene, a rat homologue of von Hippel-Lindau disease gene (VHL) as well as Tsc2 gene. RESULTS: BP36B showed an abnormal mobility shift from the normal tissue of the same rat in exon 35 on analysis by PCR-SSCP. This mutation was confirmed by direct sequencing and found to be a T-to-C transition at the second position of codon 1470, resulting in an amino acid change from leucine to proline (missense mutation). CONCLUSIONS: This is the first demonstration of Tsc2 gene somatic mutation in non-Eker rat RCs. Our present findings call attention to further investigation of the role of Tsc2 gene mutations in rat renal carcinogenesis and possible Tsc2 gene mutations in human RCs, especially of the non-clear cell type, which are not related to the VHL gene.

Animals↗
PubMed1997

Intragenic Tsc2 somatic mutations as Knudson's second hit in spontaneous and chemically induced renal carcinomas in the Eker rat model.

We searched for the rat homologue of the human tuberous sclerosis (TSC2) gene mutations in loss of heterozygosity (LOH)-negative Eker rat renal carcinomas (RCs) by polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis using 45 primer sets covering all 41 coding exons and one leader exon including splicing donor/acceptor sites. We have identified intragenic somatic mutations in 7 of 21 spontaneous RCs, including one cell line (33%), and in 3 of 9 (33%) N-ethyl-N-nitrosourea (ENU)-induced LOH-negative RCs. Interestingly, five mutations in the spontaneous RCs were either deletion or duplication (5/7 = 71%). In contrast, all three in ENU-induced RCs were base substitutions (3/3 = 100%), as expected. Thus, a qualitative difference in the second hit might exist between spontaneous and ENU-induced mutations (e.g., deletion or duplication versus point mutation). By a direct cloning approach utilizing the restriction length difference caused by germline insertional mutation or reverse transcriptase-PCR analysis in two applicable cases, we could clearly show the presence of intragenic somatic mutations in the second copy (wild-type) of the Tsc2 gene. This is the first demonstration at the DNA sequence level of the validity of Knudson's two-hits hypothesis in the Tsc2 gene.

Alleles↗
PubMed1997

[Knudson's "two-hit" hypothesis in familial cancer syndromes].

Cancer is a heritable disorder of somatic cells. Environment and hereditary both operate in the origin of human cancer. Hereditary cancer is rare, but it has served as a useful model in the understanding of carcinogenesis. A number of cancer genes have been identified by the study of hereditary cancers and implicated in sporadic forms of the same tumors. In this article, I reviewed Knudson's famous "two-hit" hypothesis of tumor suppression.

Genes, Tumor Suppressor↗
PubMed1997

[VHL gene and TSC 2 gene].

Hereditary cancer is rare, but it has served as a useful model in the understanding of carcinogenesis. A number of cancer genes have been identified by the study of hereditary human cancers and implicated in sporadic forms of the some tumors. In this article, I reviewed von Hippel-Lindau disease (VHL) gene and tuberous sclerosis 2 (TSC 2) gene.

Animals↗
PubMed1996

TNF-alpha gene expression in the liver of the IFN-gamma transgenic mouse with chronic active hepatitis.

Cytokine gene expression in the liver of transgenic mouse which specifically expresses interferon-gamma gene (IFN-gamma) was measured using polymerase chain reaction analysis. IFN-gamma mRNA was found to be expressed in the transgenic mouse liver along with TNF-alpha mRNA. Messenger RNAs of CD4 and CD8, maturation markers of T cells, were expressed in both normal and transgenic mouse livers, indicating the presence of resident T cells. The level of CD4 and CD8 expression was slightly elevated in the transgenic mouse case, indicating an increased number of CD4+ and/or CD8+ T cells, but the lack of the activation marker IL-2 mRNA suggested a nonactivated state. TGF-beta 1 mRNA was expressed in both normal and transgenic mouse livers without any increase in the latter, and therefore does not appear to be involved in the development of chronic active hepatitis in this transgenic mouse. Since TNF-alpha is a terminal mediator of liver injury in several animal liver injury models, its high expression, presumably a result of the IFN-gamma which is transcribed from the introduced gene, might be involved in the development of chronic active hepatitis in this transgenic mouse.

Alanine Transaminase↗
PubMed1996

Molecular cloning of a rat chromosome putative recombinogenic sequence homologous to the hepatitis B virus encapsidation signal.

Previously, we reported that a 61-bp subgenomic HBV DNA sequence (designated as 15AB, nt 1855-1915) is a hot spot for genomic recombination and that a cellular protein binding to 15AB may be the putative recombinogenic protein. In the present study, we established the existence of a 15AB-like sequence in human and rat chromosomal DNA by Southern blot analysis. The 15AB-like sequence isolated from the rat chromosome demonstrated a 80.9% identity with 5'-CCAAGCTGTGCCTTGGGTGGC-3', at 1872-1892 of the hepatitis B virus genome, thought to be the essential region for recombination. Interestingly, this 15AB-like sequence also contained the pentanucleotide motifs GCTGG and CCAGC as an inverted repeat, part of the chi known hot spot for recombination in Escherichia coli. Importantly, a portion of the 15AB-like sequence is homologous (82.1%, 23/28 bp) to break point clusters of the human promyelocytic leukemia (PML) gene, characterized by a translocation [t(15;17)], and to rearranged mouse DNA for the immunoglobulin kappa light chain. Moreover, 15AB and 15AB-like sequences have striking homologies (12/15 = 80.0% and 13/15 = 86.7%, respectively) to the consensus sequence for topoisomerase II. Our present results suggest that this 15AB-like sequence in the rat genome might be a recombinogenic candidate triggering genomic instability in carcinogenesis.

Animals↗