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1.
Oncogene ; 25(41): 5693-706, 2006 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-16636668

RESUMO

The short arm of chromosome 8, 8p, is often rearranged in carcinomas, typically showing distal loss by unbalanced translocation. We analysed 8p rearrangements in 48 breast, pancreatic and colon cancer cell lines by fluorescence in situ hybridization (FISH) and array comparative genomic hybridization, with a tiling path of 0.2 Mb resolution over 8p12 and 1 Mb resolution over chromosome 8. Selected breast lines (MDA-MB-134, MDA-MB-175, MDA-MB-361, T-47D and ZR-75-1) were analysed further. Most cell lines showed loss of 8p distal to a break that was between 31 Mb (5' to NRG1) and the centromere, but the translocations were accompanied by variable amplifications, deletions and inversions proximal to this break. The 8p12 translocation in T-47D was flanked by an inversion of 4 Mb, with a 100 kb deletion at the proximal end. The dicentric t(8;11) in ZR-75-1 carries multiple rearrangements including interstitial deletions, a triplicated translocation junction between NRG1 and a fragment of 11q (unconnected to CCND1), and two separate amplifications, of FGFR1 and CCND1 . We conclude that if there is a tumour suppressor gene on 8p it may be near 31 Mb, for example WRN; but the complexity of 8p rearrangements suggests that they target various genes proximal to 31 Mb including NRG1 and the amplicon centred around ZNF703/FLJ14299.


Assuntos
Neoplasias da Mama/genética , Aberrações Cromossômicas , Cromossomos Humanos Par 8 , Neoplasias do Colo/genética , Neoplasias Pancreáticas/genética , Linhagem Celular Tumoral , Cromossomos Artificiais Bacterianos , Amplificação de Genes , Humanos , Hibridização in Situ Fluorescente , Hibridização de Ácido Nucleico
2.
J Clin Invest ; 78(2): 389-97, 1986 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-3734098

RESUMO

Rabbit aortic endothelial cells (RAEC) were grown on micropore filters in a new device. This system allowed in situ measurement of transendothelial electrical resistance (TEER). The monolayers demonstrated a TEER of 14 +/- 1 omega X cm2 at confluence. No difference was seen in the transport of low density lipoproteins (LDL) across endothelial cell monolayers obtained from normal or Watanabe heritable hyperlipidemic rabbits, indicating that the LDL receptor was not involved in the LDL transport. TEER was inversely correlated with 22Na transport (r2 = 0.93, P = less than 0.001) but not with 125I-LDL transport. The amount of LDL transported at 15 degrees C or across glutaraldehyde-fixed monolayers was half that of the controls at 37 degrees C. Preincubation of the monolayers with rabbit beta-migrating very low density lipoproteins (beta-VLDL) increased cholesterol content by 65%, and the transport of albumin and LDL doubled without a change in TEER. Removal of beta-VLDL from the culture medium resulted in the return of cellular cholesterol content and LDL transport to control values. We conclude that preincubation of RAEC with beta-VLDL resulted in an increased permeability to LDL and albumin, and that beta-VLDL may promote increased transendothelial transport of macromolecules in cholesterol-fed rabbits.


Assuntos
Condutividade Elétrica , Endotélio/efeitos dos fármacos , Lipoproteínas VLDL/farmacologia , Albuminas/metabolismo , Animais , Aorta , Transporte Biológico/efeitos dos fármacos , Células Cultivadas , Endotélio/metabolismo , Endotélio/ultraestrutura , Humanos , Lipoproteínas LDL/metabolismo , Substâncias Macromoleculares , Microscopia Eletrônica , Coelhos , Sódio/metabolismo
3.
Mol Cell Biol ; 7(9): 3138-46, 1987 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3670308

RESUMO

Differential hybridization and molecular cloning have been used to isolate CR39, a cDNA which hybridizes to a 1.2-kilobase (kb) mRNA in rat liver. The level of CR39 mRNA was increased seven- to ninefold over normal levels by dietary cholestyramine and mevinolin and decreased about fourfold compared with normal levels by cholesterol feeding or administration of mevalonate. Similar changes in the mRNA levels of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase and HMG-CoA synthase were observed under the various conditions. In vitro translation of either CR39 hybrid selected RNA or 1.2-kb CR39 RNA generated by an SP6 in vitro transcription system produced a polypeptide of 39,000 daltons. As deduced from the nucleotide sequence of a full-length CR39 cDNA, the rat CR39 polypeptide contained 344 amino acids and had a molecular weight of 39,615. The predicted amino acid composition and submit molecular weight of the rat CR39 were very similar to those of prenyltransferases isolated from chicken, pig, and human. The sequence of amino acid residues 173 through 203 in the rat CR39 polypeptide showed that 17 out of 30 matched an active-site peptide of avian liver prenyltransferase. Thus, alterations in the rate of cholesterogenesis resulted in the coordinate regulation of three mRNAs encoding HMG-CoA reductase, HMG-CoA synthase, and CR39, the latter being tentatively identified as prenyltransferase.


Assuntos
Colesterol/fisiologia , Dimetilaliltranstransferase/genética , Transferases/genética , Sequência de Aminoácidos , Aminoácidos/análise , Sequência de Bases , Clonagem Molecular , DNA/genética , Repressão Enzimática , Fígado/enzimologia , Dados de Sequência Molecular
4.
Mol Cell Biol ; 10(5): 2315-26, 1990 May.
Artigo em Inglês | MEDLINE | ID: mdl-2325654

RESUMO

A variety of rat tissues were screened at low stringency with a rat farnesyl pyrophosphate (FPP) synthetase cDNA. In testis, an FPP synthetase-related RNA was detected that was larger than the liver FPP synthetase mRNA and was present at very high levels comparable with liver FPP synthetase RNA levels obtained from rats fed diets supplemented with cholestyramine and mevinolin. Sequence analysis of testis cDNA clones, together with primer extension and S1 nuclease experiments, indicated that testis FPP synthetase transcripts contain an extended 5' untranslated region. The 5' extension contained one or two out-of-frame upstream ATGs, depending on the site of transcription initiation. Protein in vitro translation studies indicated that the extended 5' untranslated region may play a role in regulating the translation of the FPP synthetase polypeptide in rat testis. Southern blot analysis with a probe containing both testis and liver 5' untranslated sequences provided evidence that both liver and testis transcripts derive from the same gene. The data suggest that an upstream testis-specific promoter results in the abundant production of FPP synthetase transcripts that are translated at low efficiency; another promoter functions in liver and other somatic tissues and directs the regulated synthesis of shorter discrete transcripts.


Assuntos
Dimetilaliltranstransferase/genética , Testículo/fisiologia , Transcrição Gênica , Transferases/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Northern Blotting , Expressão Gênica , Fígado/fisiologia , Masculino , Dados de Sequência Molecular , Biossíntese de Proteínas , RNA Mensageiro/genética , Ratos , Ratos Endogâmicos
5.
Oncogene ; 8(6): 1551-8, 1993 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8099220

RESUMO

We have developed a transplantation system that allows us to introduce oncogenes into mouse mammary epithelial cells in culture and then to reconstitute an epithelial tree in vivo from the genetically altered cells. Introduction of the neu oncogene, a transforming homologue of the human proto-oncogene c-erbB-2, produced a variety of abnormal patterns of epithelial growth, many of which resembled lesions found in human breasts. In four of 43 oncogene-bearing glands, areas of ductal carcinoma in situ were found, an abnormality previously observed in transgenic neu-bearing mice. Six glands developed localized areas of dense stroma containing excess ductal structures comprised of mildly hyperplastic epithelium. These areas resembled the human breast lesion termed sclerosing adenosis. Other glands developed hyperplastic epithelium, sometimes with multilayering of the cells and/or atypical changes such as abnormally large nuclei. In human breasts such lesions would be termed mild or atypical hyperplasia. In all the abnormal areas examined, levels of neu protein above background level were detected by immunohistochemistry. Some staining was localized to membranes (as observed in ductal carcinoma in situ in humans) but cytoplasmic staining was also common in the lesions induced in mice by the neu oncogene. The range of abnormalities seen in the reconstituted glands carrying the neu oncogene suggests that the matching lesions in the human breast may be stages on one pathway to tumour development.


Assuntos
Neoplasias da Mama/genética , Glândulas Mamárias Animais/patologia , Neoplasias Mamárias Experimentais/genética , Oncogenes , Proteínas Proto-Oncogênicas/genética , Células 3T3 , Animais , Neoplasias da Mama/patologia , Carcinoma in Situ/genética , Carcinoma in Situ/patologia , Carcinoma Intraductal não Infiltrante/genética , Carcinoma Intraductal não Infiltrante/patologia , Epitélio/patologia , Feminino , Humanos , Neoplasias Mamárias Experimentais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Transplante de Neoplasias , Proto-Oncogene Mas , Ratos , Receptor ErbB-2 , Mapeamento por Restrição , Retroviridae/genética
6.
Oncogene ; 9(9): 2597-603, 1994 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-8058323

RESUMO

Retroviral vectors were used to introduce members of the Wnt gene family into the embryonic fibroblast cell line C3H 10T1/2. In contrast to previous reports where no effect of Wnt genes on fibroblasts was seen, we found that the expression of Wnt-1, Wnt-6 and Wnt-7b altered the appearance of the cells when maintained at confluence. The cells were smaller and grew to a higher density than cells containing a control retrovirus or cells expressing Wnt-4 or Wnt-5b. Detailed analysis of growth characteristics of polyclonally infected cultures demonstrated that the Wnt-1, Wnt-6 and Wnt-7b expressing cells grew to a higher density in 5% fetal calf serum than control or Wnt-5b expressing cells. Wnt-4 expressing cells grew to a marginally higher density than control cells. In 0.5% serum, growth of the Wnt-1, Wnt-6 and Wnt-7b containing cells appeared to be inhibited. No growth in soft agar was observed for either control cells or Wnt expressing cells. We conclude that at least some mesenchymal cells can respond to Wnt gene products. Our results are also the first report of biological effects of Wnt-6 and Wnt-7b.


Assuntos
Transformação Celular Neoplásica , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Proteínas de Peixe-Zebra , Animais , Sequência de Bases , Divisão Celular , Células Cultivadas , Fibroblastos/fisiologia , Expressão Gênica , Camundongos , Camundongos Endogâmicos C3H , Dados de Sequência Molecular , Transfecção , Proteínas Wnt , Proteína Wnt1
7.
Oncogene ; 2(4): 407-12, 1988 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-3283657

RESUMO

To see if individual oncogenes can alter three-dimensional growth in vivo, we have inserted the v-myc oncogene into transplants of mouse mammary gland. Primary cultures of mammary epithelial cells were infected with helper-free retrovirus to insert v-myc oncogenes, and transplanted into cleared mammary fat pads (mammary glands from which the natural epithelium had been removed) of host mice. Uninfected transplants, and transplants infected with retrovirus constructs that carry no oncogene, grew to form an epithelial 'tree' resembling normal mammary gland, as expected. Transplants infected with retroviruses carrying v-myc oncogenes grew to form a characteristic, abnormal (hyperplastic) pattern in which the ducts were more densely packed than normal. Integration of the retrovirus in the transplants was demonstrated. The effect of the oncogene was local, not systemic, as some transplants showed adjacent areas of normal and hyperplastic growth. Thus v-myc can alter morphogenesis without growth becoming disorganized.


Assuntos
Glândulas Mamárias Animais/transplante , Proteínas dos Retroviridae/fisiologia , Animais , Epitélio/patologia , Feminino , Hiperplasia , Glândulas Mamárias Animais/patologia , Camundongos , Morfogênese , Proteína Oncogênica p55(v-myc) , Proteínas dos Retroviridae/genética , Transfecção
8.
Oncogene ; 7(10): 2041-51, 1992 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-1408145

RESUMO

We have expressed the Wnt-1 (formerly int-1) oncogene in Balb/c mouse mammary epithelium in vivo, using a tissue reconstitution method in which primary cultures of mammary epithelial cells are infected with a retrovirus vector and then transplanted into mouse mammary fat pads from which the natural epithelium has been removed. Transplants carrying the Wnt-1 gene grew in a hyperplastic pattern, the duct epithelium showing abundant fine side-branches, but without development of clusters of alveoli. The hyperplasias were similar, but not identical, to transplants of normal epithelium in a mid-pregnant host. Transplants of epithelium that expressed Wnt-1 into mammary fat pads of male or ovariectomized females grew to form a similar three-dimensional pattern, but the extent of growth, and so presumably the rate of growth, was slower than in intact females, and there were no terminal end buds at the edges of the outgrowths. Thus, although Wnt-1 may enhance growth of epithelium in the male or ovariectomized-female environment, it does not restore the major mode of growth in the intact female, the extension of major ducts from terminal end buds. Normal epithelium showed no change in morphology when in close proximity to hyperplasia induced by Wnt-1, confirming the limited range of diffusion of Wnt-1 protein in vivo. Our results are consistent with the hypothesis that Wnt-1 acts principally by mimicking the signal that causes ducts to develop side-branches in pregnancy.


Assuntos
Expressão Gênica , Glândulas Mamárias Animais/patologia , Proteínas Proto-Oncogênicas/genética , Proto-Oncogenes , Proteínas de Peixe-Zebra , Animais , Carcinoma in Situ/etiologia , Epitélio/patologia , Feminino , Hiperplasia , Masculino , Glândulas Mamárias Animais/química , Glândulas Mamárias Animais/transplante , Neoplasias Mamárias Experimentais/etiologia , Camundongos , Camundongos Endogâmicos BALB C , Ovariectomia , Gravidez , Proteínas Proto-Oncogênicas/análise , Proteínas Wnt , Proteína Wnt1
9.
Oncogene ; 18(56): 8024-32, 1999 Dec 23.
Artigo em Inglês | MEDLINE | ID: mdl-10637513

RESUMO

The serine threonine kinase protein kinase B regulates cellular activities as diverse as glycogen metabolism and apoptosis. Full activation of protein kinase B requires 3-phosphoinositides and dual phosphorylation on threonine-308 and serine-473. CaM-K kinase and 3-phosphoinositide dependent-kinase-1 phosphorylate threonine-308. Integrin-linked kinase reportedly phophorylates serine-473. Consistent with this, in a model COS cell system we show that expression of wild-type integrin-linked kinase promotes the wortmannin sensitive phosphorylation of serine-473 of protein kinase B and its downstream substrates, and inhibits C2-ceramide induced apoptosis. In contrast, integrin-linked kinase mutated in a lysine residue critical for function in protein kinases is inactive in these experiments, and furthermore, acts dominantly to block serine-473 phosphorylation induced by ErbB4. However, alignment of analogous sequences from different species demonstrates that integrin-linked kinase is not a typical protein kinase and identifies a conserved serine residue which potentially regulates kinase activity in a phosphorylation dependent manner. Mutation of this serine to aspartate or glutamate, but not alanine, in combination with the inactivating lysine mutation restores integrin-linked kinase dependent phosphorylation of serine-473 of protein kinase B. These data strongly suggest that integrin-linked kinase does not possess serine-473 kinase activity but functions as an adaptor to recruit a serine-473 kinase or phosphatase.


Assuntos
Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Sequência de Aminoácidos , Animais , Células COS , Caenorhabditis elegans , Proteínas de Caenorhabditis elegans , Domínio Catalítico , Proteínas de Drosophila , Drosophila melanogaster , Humanos , Dados de Sequência Molecular , Fosfatidilinositóis/metabolismo , Fosforilação , Fosfosserina/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/química , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-raf/química , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Alinhamento de Sequência , Homologia de Sequência de Aminoácidos , Transfecção
10.
Biochim Biophys Acta ; 409(1): 39-50, 1975 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-241422

RESUMO

Incubation of rat hepatocytes for 3 h in a medium containing amino acids, salts and albumin resulted in a 2-fold increase in the activity of 3-hydroxy-3-methylglutaryl-CoA reductase. Inclusion of 10% human plasma, rat serum or dialysed rat serum in the medium resulted in an approximate 7-fold increase in reductase activity. These increases were specific since there was little change in the rate of fatty acid synthesis or in the activity of tyrosine aminotransferase. Reductase levels were increased above control values when high density lipoproteins or leithin dispersions were added to the cells. Lecithin dispersions were also shown to increase the rate of efflux of cell cholesterol to the medium. In contrast, reductase levels were reduced when cells were incubated with low density lipoproteins or cholesterol added as an equimolar cholesterol-lecithin dispersion. This inhibition of the reductase by cholesterol dispersions was dependent on the continued de novo protein synthesis. Our data indicate that in normal rat hepatocytes the relative rates of efflux and influx of cholesterol may be critical to the regulation of 3-hydroxy-3-methylglutaryl-CoA reductase activity and cholesterogenesis.


Assuntos
Oxirredutases do Álcool/metabolismo , Hidroximetilglutaril-CoA Redutases/metabolismo , Lipoproteínas/sangue , Fígado/enzimologia , Acetatos/metabolismo , Animais , Colesterol/sangue , Colesterol/farmacologia , Cicloeximida/farmacologia , Ácidos Graxos/biossíntese , Humanos , Lipídeos/biossíntese , Fígado/citologia , Ácido Mevalônico/metabolismo , Fosfatidilcolinas/farmacologia , Ratos , Tirosina Transaminase/metabolismo
11.
Biochim Biophys Acta ; 574(1): 123-35, 1979 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-476131

RESUMO

3-Hydroxy-3-methylglutaryl coenzyme A reductase has been purified from rat liver microsomes with a recovery of approx. 25%. The enzyme was homogeneous on gel electrophoresis and enzyme activity comigrated with the single protein band. The molecular weight of the reductase determined by gel filtration on Sephadex G-200 was 200,000. SDS-polyacrylamide gel electrophoresis gave a subunit molecular weight of 52,000 +/- 2000, suggesting that the enzyme was a tetramer. The specific activities of the purified enzyme obtained from rats fed diets containing 0% or 5% cholestyramine were 11,303 and 19,584 nmol NADPH oxidized/min per mg protein, respectively. The reductase showed unique binding properties to Cibacron Blue Sepharose; the enzyme was bound to the Cibacron Blue via the binding sites for both substrates, NADPH and (S)-3-hydroxy-3-methylglutaryl coenzyme A. Antibodies prepared against purified reductase inactivated 100% of the soluble and at least 91% of the microsomal enzyme activity. Immunotitrations of solubilized enzyme obtained from normal and cholestyramine-fed rats indicated that cholestyramine feeding both increased the amount of enzyme protein and resulted in enzyme activation. Administration of increasing amounts of mevalonolactone to rats decreased the equivalence point obtained from immunotitration studies with solubilized enzyme. These data indicate that the antibody cross-reacts with the inactive enzyme formed after mevalonolactone treatment.


Assuntos
Hidroximetilglutaril-CoA Redutases/isolamento & purificação , Fígado/enzimologia , Animais , Anticorpos , Sítios de Ligação , Resina de Colestiramina/farmacologia , Hidroximetilglutaril-CoA Redutases/imunologia , Substâncias Macromoleculares , Peso Molecular , Ratos
12.
Biochim Biophys Acta ; 1529(1-3): 103-13, 2000 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-11111080

RESUMO

Sterol regulatory element binding proteins (SREBPs) function as transcription factors that activate specific genes involved in cholesterol synthesis, endocytosis of low density lipoproteins, the synthesis of both saturated and unsaturated fatty acids and glucose metabolism. As such, these proteins provide a link between lipid and carbohydrate metabolism. There are three SREBPs, SREBP-1a, SREBP-1c and SREBP-2, that are encoded by two genes. SREBPs are synthesized as 125 kDa precursor proteins that are localized to the endoplasmic reticulum. The precursor is transported to the Golgi by a chaperone protein (SREBP-cleavage activating protein) and then cleaved by two proteases to release the mature, transcriptionally active 68 kDa amino terminal domain. Recent studies have shown that formation of mature SREBP is controlled at multiple levels in response to changes in the levels of oxysterols, insulin/glucose and polyunsaturated fatty acids. These recent findings have important clinical implications relevant to hyperlipidemia and diabetes and are the topic of this review.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/farmacologia , Proteínas de Ligação a DNA/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Membrana/farmacologia , Fatores de Transcrição , Metabolismo dos Carboidratos , Colesterol/metabolismo , Ácidos Graxos Insaturados/farmacologia , Insulina/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular , Metabolismo dos Lipídeos , Modelos Químicos , Proteína de Ligação a Elemento Regulador de Esterol 1 , Transcrição Gênica
13.
Biochim Biophys Acta ; 1003(3): 293-300, 1989 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-2472835

RESUMO

Cloned cDNAs encoding a number of enzymes involved in cholesterol biosynthesis as well as extracellular and intracellular lipid transport were used to compare the developmental maturation of these biologic functions in the fetal and neonatal rat and human liver. The results of RNA blot hybridization analyses indicate that steady-state levels of rat HMG-CoA synthase, HMG-CoA reductase and prenyl transferase mRNAs are highest in late fetal life and undergo precipitous (up to 80-fold) co-ordinate reductions immediately after parturition. These changes reflect the ability of the fetal rat liver to produce large quantities of cholesterol as well as the repression of this function during the suckling period in response to exogenous dietary cholesterol. Striking co-ordinate patterns of HMG-CoA synthase, reductase and prenyl-transferase mRNA accumulation were also observed in four extrahepatic rat tissues (brain, lung, intestine and kidney) during the perinatal period. The concentrations of all three mRNAs in the 8-week-old human fetal liver are similar to those observed throughout subsequent intrauterine development with less than 2-fold changes noted between the 8th through 25th weeks of gestation. Analysis of the levels of human apo AI, apo AII, apo B and liver fatty acid binding protein mRNAs during this period and in newborn liver specimens also indicated less than 2-3-fold changes. These observations suggest that the 8-week human liver has achieved a high degree of biochemical differentiation with respect to functions involved in lipid metabolism/transport which may be comparable to that present in 19-21 day fetal rat liver. Further analysis of human and rat fetal liver RNAs using cloned cDNAs should permit construction of a developmental time scale correlating hepatic biochemical differentiation to be constructed between these two mammalian species.


Assuntos
Colesterol/biossíntese , Dimetilaliltranstransferase/genética , Hidroximetilglutaril-CoA Redutases/genética , Hidroximetilglutaril-CoA Sintase/genética , Metabolismo dos Lipídeos , Fígado/fisiologia , Oxo-Ácido-Liases/genética , Transferases/genética , Animais , Transporte Biológico , Northern Blotting , Encéfalo/fisiologia , Regulação da Expressão Gênica , Humanos , Intestinos/fisiologia , Rim/fisiologia , Fígado/embriologia , Fígado/metabolismo , Ratos , alfa-Fetoproteínas/genética
14.
Mol Endocrinol ; 15(10): 1720-8, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11579204

RESUMO

The farnesoid X-activated receptor (FXR; NR1H4), a member of the nuclear hormone receptor superfamily, induces gene expression in response to several bile acids, including chenodeoxycholic acid. Here we used suppression subtractive hybridization to identify apolipoprotein C-II (apoC-II) as an FXR target gene. Retroviral expression of FXR in HepG2 cells results in induction of the mRNA encoding apoC-II in response to several FXR ligands. EMSAs demonstrate that recombinant FXR and RXR bind to two FXR response elements that are contained within two important distal enhancer elements (hepatic control regions) that lie 11 kb and 22 kb upstream of the transcription start site of the apoC-II gene. A luciferase reporter gene containing the hepatic control region or two copies of the wild-type FXR response element was activated when FXR-containing cells were treated with FXR ligands. In addition, we report that hepatic expression of both apoC-II and phospholipid transfer protein mRNAs increases when mice are fed diets supplemented with cholic acid, an FXR ligand, and this induction is attenuated in FXR null mice. Finally, we observed decreased plasma triglyceride levels in mice fed cholic acid- containing diets. These results identify a mechanism whereby FXR and its ligands lower plasma triglyceride levels. These findings may have important implications in the clinical management of hyperlipidemias.


Assuntos
Apolipoproteínas C/genética , Ácidos e Sais Biliares/administração & dosagem , Proteínas de Ligação a DNA/fisiologia , Proteínas de Transferência de Fosfolipídeos , Fatores de Transcrição/fisiologia , Transcrição Gênica , Triglicerídeos/sangue , Animais , Apolipoproteína C-II , Proteínas de Transporte/genética , Ácido Cólico/administração & dosagem , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Dieta , Elementos Facilitadores Genéticos , Expressão Gênica , Vetores Genéticos , Humanos , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Mensageiro/análise , RNA Mensageiro/biossíntese , Ratos , Receptores Citoplasmáticos e Nucleares , Proteínas Recombinantes , Elementos de Resposta , Retroviridae/genética , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Transfecção , Células Tumorais Cultivadas
15.
Gene ; 196(1-2): 187-9, 1997 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-9322757

RESUMO

A new retroviral vector has been constructed that expresses genes encoding three different activities from a single transcript. This feature has been exploited to enable the efficient marking and selection of cells that express a gene of interest. The marker gene lacZ, encoding beta-galactosidase, and neo, encoding neomycin phosphotransferase, for selection by the antibiotic G418, are expressed as a fusion, beta Geo. The expression of beta Geo is coordinated with expression of a gene of interest at the mRNA level using an Internal Ribosome Entry Site (IRES) from the Encephalomyocarditis Virus (EMCV). The IRES promotes cap-independent initiation of translation therefore two reading frames can be translated from a single transcript. In vitro, the vector has been shown to confer beta-galactosidase activity, transformation by v-src and resistance to G418, following infection of cells. To show that the retrovirus was able to mark infected cells in vivo, cells infected with the retrovirus were transplanted into mouse mammary gland where they grew and were successfully located by staining for beta-galactosidase over 2 months after transplantation.


Assuntos
Vetores Genéticos/genética , Proteínas Recombinantes/genética , Retroviridae/genética , Seleção Genética , Animais , Canamicina Quinase/genética , Canamicina Quinase/metabolismo , Glândulas Mamárias Animais/virologia , Camundongos , Dados de Sequência Molecular , Proteína Oncogênica pp60(v-src)/genética , Proteína Oncogênica pp60(v-src)/metabolismo , Proteínas Recombinantes/metabolismo , Ribossomos/genética , beta-Galactosidase/genética , beta-Galactosidase/metabolismo
16.
Biochem Soc Symp ; 63: 21-34, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9513708

RESUMO

The mammary gland is possibly the best system in which to study the three-dimensional organization of tissues and how that organization is disrupted in tumour development. The principal approach used has been to express genes such as oncogenes and growth factor genes in mammary epithelium in vivo, by using mammary-specific promoters in germ-line transgenic mice; by injecting virus vectors into the lumen of the mammary gland; or by transplanting genetically manipulated mammary epithelial cells into a mammary fat pad from which the natural epithelium has been removed. This chapter focuses on the last approach. The Wnt genes are short-range signalling molecules related to Wnt-1, which was discovered as an oncogene in mouse mammary tumours. Several Wnt proteins are expressed in the mammary gland; notably, Wnt-4 is normally expressed in early pregnancy. Introducing Wnt-4 into the mammary epithelium of virgin mice induces a growth pattern very similar to that of mid-pregnancy. Wnt-4 may therefore be a local signal driving epithelial branching in pregnancy. ErbB/epidermal growth factor receptor and ErbB-2 are receptors that may be important in breast tumour development and normal mammary growth control. Overactive mutants of them, i.e. the genes v-erbB and neu, disturb the growth pattern of the mammary epithelium in quite distinct ways. Overactive ErbB-2 causes local development of alveoli, suggesting that it may be involved in normal alveolus development. The varied effects of these gene products show the complexity of the control of the three-dimensional growth pattern, and encourage the idea that we may be able to relate oncogenic effects to normal growth controls.


Assuntos
Glândulas Mamárias Animais/crescimento & desenvolvimento , Mitógenos , Proteínas Proto-Oncogênicas/genética , Receptor ErbB-2/genética , Proteínas de Peixe-Zebra , Animais , Epitélio/crescimento & desenvolvimento , Epitélio/metabolismo , Feminino , Expressão Gênica , Glândulas Mamárias Animais/metabolismo , Camundongos , Camundongos Transgênicos , Gravidez , Proteínas Wnt , Proteína Wnt1
17.
Cytogenet Genome Res ; 104(1-4): 333-40, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15162061

RESUMO

A large proportion of epithelial cancers show the chromosome-instability phenotype, in which they have many chromosome abnormalities. This is thought to be the result of mutations that disrupt chromosome maintenance, but the causative mutations are not known. We identified cell lines known to have mutations that might cause chromosome instability, and examined their karyotypes. Two cell lines, the breast cancer line HCC1937 and the pancreatic cancer line CAPAN-1, that have mutations respectively in BRCA1 and BRCA2, had very abnormal karyotypes, with many structural and numerical chromosome changes and substantial variation between metaphases. However, two colorectal cancer lines with mutations in BUB1, a spindle checkpoint protein involved in chromosome segregation, had rather simple near-tetraploid karyotypes, with minimal loss or gain of chromosomes other than the endoreduplication event, and minimal structural change. Apart from tetraploidy, these karyotypes were typical of colorectal lines considered to be chromosomally stable. Two lines derived from the same tumour, DLD-1 and HCT-15, with bi-allelic mutation of CHK2, had karyotypes that were typical of near-diploid colorectal lines considered chromosomally stable. The karyotypes observed supported the proposed role for BRCA1 and BRCA2 mutations in chromosomal instability, but showed that the tested mutations in BUB1 and CHK2 did not result in karyotypes that would have been predicted if they were sufficient for chromosomal instability.


Assuntos
Linhagem Celular Tumoral/ultraestrutura , Instabilidade Cromossômica/genética , Aberrações Cromossômicas , Cromossomos Humanos/ultraestrutura , Genes BRCA1 , Genes BRCA2 , Proteínas Quinases/genética , Proteínas Serina-Treonina Quinases/genética , Adenocarcinoma/genética , Adenocarcinoma/patologia , Aneuploidia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Quinase do Ponto de Checagem 2 , Coloração Cromossômica , Cromossomos Humanos/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Análise Mutacional de DNA , DNA de Neoplasias/genética , Humanos , Cariotipagem , Metáfase , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/patologia , Translocação Genética
18.
J Histochem Cytochem ; 32(5): 531-7, 1984 May.
Artigo em Inglês | MEDLINE | ID: mdl-6371134

RESUMO

Three monoclonal antibodies raised to the human milk fat globule membrane bind, within the normal breast, to the surface of the luminal epithelial cells but not to the surrounding myoepithelial, connective tissue, or blood vessel cells. These antibodies distinguish three subsets of the epithelial cells that are not distinguishable by conventional histology. To show the arrangement of the cells in two dimensions over the sheet of epithelium, ducts were dissected out of normal breast tissue, opened up and laid flat as sheets of epithelium. The apical faces of the cells were strained, unfixed, using two-color immunofluorescence to contrast the subsets of cells stained by the different antibodies. The epithelium was then seen to be a mosaic of cells that express different surface antigens. The grouping and appearance of the cells stained by the different antibodies was characteristic. This may be just a random heterogeneity of antigen expression but alternatively the different cells may be in different physiological states. Regardless of its biological significance, the observation has practical consequences for the use of such antibodies in identifying cells and the study of antigenic heterogeneity in tumors.


Assuntos
Anticorpos Monoclonais/imunologia , Antígenos de Superfície/análise , Mama/imunologia , Imunofluorescência , Antígenos de Superfície/classificação , Epitélio/imunologia , Feminino , Fluoresceínas , Secções Congeladas , Histocitoquímica , Humanos , Microscopia de Fluorescência , Leite Humano/imunologia , Rodaminas
19.
Invest Ophthalmol Vis Sci ; 28(10): 1707-10, 1987 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3654143

RESUMO

We conducted reproducibility studies on an in vivo objective method of documenting cataracts: Scheimpflug photography using the Topcon SL 45 camera. Normal and cataractous lenses were photographed and the photographs digitized and analyzed using a Perkin Elmer microdensitometer attached to a PDP 11 and Vax 11/780 computer. Linear densitometry was performed through the center of the lens. We found very good reproducibility. The intraclass correlation for the mean densities in the nucleus was 0.95: that is, intra- and interobserver variability accounted for only 5% of the overall variability. For the anterior cortex, intraclass correlation was 0.88 and for posterior cortex it was 0.84. This method may be useful, within limits, in future clinical trials of anticataract medications.


Assuntos
Catarata/patologia , Fotografação , Densitometria , Humanos , Processamento de Imagem Assistida por Computador
20.
Invest Ophthalmol Vis Sci ; 34(1): 263-9, 1993 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8425834

RESUMO

PURPOSE: To study the changes in density and thickness in normal lenses related to aging, and to study changes in anterior chamber depth related to aging. METHODS: Eighty nine normal volunteers (ages 9-80 yr) were examined and their eyes were photographed to obtain Scheimpflug photographs. The images were digitized and linear densitometry was performed, dividing the lens into five areas: posterior capsular (area 1), posterior cortical (area 2), nuclear (area 3), anterior cortical (area 4), and anterior capsular (area 5). Total lens thickness and anterior chamber depth were similarly measured for 90 normal eyes from the densitometry profiles. These were correlated with age. RESULTS: There was a strong positive correlation between increasing age and the density in all lens areas (area 2: r = 0.805; P < 0.0001; area 3: r = 0.836, P < 0.0001; area 4: r = 0.767, P < 0.0001; and area 5: r = 0.319, P < 0.0023), except the posterior capsular area, where correlation was negative (area 1: r = -0.426; P < 0.0001). In addition, there was a significant correlation between age and overall lens thickness (r = 0.756; P < 0.0001), thickness of nucleus (r = 0.543; P < 0.0001), and cortex (r = 0.632; P < 0.0001), and a negative correlation with anterior chamber depth (r = -0.513, P < 0.0001). CONCLUSION: This report shows human lens changes in density and thickness correlated with aging using Scheimpflug photography and image analysis techniques. The results will aid future development of systems for automated detection, classification, and monitoring of human cataracts, as well as other anterior segment disorders.


Assuntos
Envelhecimento/patologia , Cristalino/anatomia & histologia , Fotografação/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Câmara Anterior/fisiologia , Antropometria , Criança , Densitometria , Humanos , Pessoa de Meia-Idade
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