Publications

anabolic steroids, testosterone-precursors and virilizing androgens induce distinct activation profiles of androgen responsive promoter constructs.	different androgens, e.g. virilizing androgens such as testosterone and its precursors as well as synthetic anabolic steroids, respectively, induce diverse biological effects. the molecular basis for this variety in biological actions, however, is not well understood. we hypothesized that this variability of actions may be due to steroid-specific target gene expression profiles following androgen receptor (ar)-activation. therefore, we investigated androgen receptor dependent transactivation of ...	2002	12589933
malignant transformation by the eukaryotic translation initiation factor 3 subunit p48 (eif3e).	several components of translation, e.g. eif4e and pkr, are implicated in cancer. the e-subunit (p48) of mammalian initiation factor 3 is encoded by the int6 gene, a common site for integration of the mouse mammary tumor virus genome, leading to the production of a truncated eukaryotic initiation factor-3e (eif3e). stable expression of a truncated eif3e in nih 3t3 cells causes malignant transformation by four criteria: foci formation; anchorage independent growth; accelerated growth; and lack of ...	2002	11904180
new tools for the construction of replication-competent adenoviral vectors with altered e1a regulation.	we have designed new vectors for the construction of recombinant adenoviruses containing the early region 1a (e1a) gene under the transcriptional control of heterologous promoters. the normal e1a regulatory elements have been replaced by a convenient set of unique restriction enzyme sites, allowing for introduction of gene regulatory cassettes with relative ease. subsequent rescue generates recombinant conditionally replicating adenovirus in which the transcription of e1a is under alternative co ...	2002	11906731
preferential infection of immature dendritic cells and b cells by mouse mammary tumor virus.	until now it was thought that the retrovirus mouse mammary tumor virus preferentially infects b cells, which thereafter proliferate and differentiate due to superantigen-mediated t cell help. we describe in this study that dendritic cells are infectable at levels comparable to b cells in the first days after virus injection. moreover, igm knockout mice have chronically deleted superantigen-reactive t cells after mmtv injection, indicating that superantigen presentation by dendritic cells is suff ...	2002	11907107
the viral transactivator e1a regulates the mouse mammary tumor virus promoter in an isoform- and chromatin-specific manner.	proteins encoded by the adenovirus e1a gene regulate both cellular and viral genes to mediate effects on cell cycle, differentiation, and cell growth control. we have identified the mouse mammary tumor virus (mmtv) promoter as a target of e1a action and investigated the role nucleoprotein structure plays in its response to e1a. both 12 and 13 s forms target the mmtv promoter when it has a disorganized and accessible chromatin configuration. however, whereas the 13 s form is stimulatory, the 12 s ...	2002	11909860
suppression of murine mammary carcinoma growth and metastasis by hsvtk/gcv gene therapy using in vivo electroporation.	the effectiveness of electroporation as a means of gene transfection, both in vitro and in vivo, was tested using the herpes simplex virus 1 thymidine kinase (hsvtk) gene in combination with ganciclovir (gcv) administration as therapy against murine mammary cancer. approximately 80% of bjmc3879 metastatic mammary carcinoma cells, derived from mmtv-infected balb/c mice, died as a result of hsvtk/gcv treatment 72 hours after the transfection; decreased dna synthesis was also seen. mammary tumors i ...	2002	11916241
mmtv-associated transcription factor binding sites increase nm23-h1 metastasis suppressor gene expression in human breast carcinoma cell lines.	we hypothesize that elevation of nm23-hi metastasis suppressor gene expression in micrometastatic tumor cells may reduce their subsequent colonization and invasion, and induce differentiation, with a clinical benefit. this report presents the first analysis of the nm23-hi promoter to identify sites which can increase its transcription. deletion mapping of a 2.1 kb nm23-h1 promoter fragment tethered to a reporter gene identified three regions involved in its differential expression levels among a ...	2002	11918081
neonatal infection with a milk-borne virus is independent of beta7 integrin- and l-selectin-expressing lymphocytes.	mouse mammary tumor virus (mmtv) is acquired by neonates through milk and first infects lymphocytes in peyer's patches. we show here that newborn mice lacking beta7 integrin or l-selectin were infected with mmtv at wild-type levels in both their lymphoid and mammary tissues. superantigen-mediated activation and cognate t cell deletion were also unimpaired in both types of null mice. a large proportion of neonatal peyer's patch lymphocytes in wild-type mice were beta7 and beta1 integrin low and b ...	2002	11920560
differential effects of p21(waf1/cip1) deficiency on mmtv-ras and mmtv-myc mammary tumor properties.	p21(waf1/cip1) (p21) functions as a cyclin-dependent kinase (cdk) inhibitor and is a key mediator of p53-dependent growth arrest. however, its role in cell cycle regulation is complex, because it also appears to promote cdk activity in certain experimental contexts. its potential role in tumor suppression was evaluated in mmtv-ras and mmtv-myc transgenic mice that were interbred to p21(waf1/cip1) knockout mice (p21-/-). p21 deficiency had differential effects on tumor incidence and age of onset, ...	2002	11929828
presence of mouse mammary tumor virus specifically alters the body odor of mice.	it has long been recognized that various genetic and metabolic human disorders alter body odor, which is not surprising because they may alter body chemistry. thus, it has been suggested that some human diseases may be diagnosed by odor alone. in that regard, the mouse mammary tumor virus (mmtv) and its tumors of mice, which may have human counterparts, are of special interest because of the need for basic research possible only in inbred and genetically defined animals. accordingly, we now show ...	2002	11929982
female pseudohermaphroditism caused by a novel homozygous missense mutation of the gr gene.	familial glucocorticoid resistance is characterized by increased cortisol secretion without clinical evidence of hypercortisolism, but with manifestations of androgen and mineralocorticoid excess. this condition is mainly caused by mutations of the gr gene that cause inadequate transduction of the glucocorticoid signal in glucocorticoid target tissues. the clinical features of glucocorticoid resistance in females include hirsutism, acne, male pattern baldness, oligomenorrhea, and oligoanovulatio ...	2002	11932321
erbb-beta-catenin complexes are associated with human infiltrating ductal breast and murine mammary tumor virus (mmtv)-wnt-1 and mmtv-c-neu transgenic carcinomas.	simultaneous deregulation of both wnt and erbb growth factors has previously been shown to result in the cooperative induction of mammary gland tumors. using the murine mammary tumor virus (mmtv)-wnt-1 transgenic model of mammary carcinoma, we have identified an unvarying association between beta-catenin and epidermal growth factor receptor/c-neu (erbb1/erbb2) heterodimers in mammary gland tumors, indicating a requirement for erbb signaling in wnt-mediated tumorigenesis. expansion of these obser ...	2002	11950845
perinatal blockade of b7-1 and b7-2 inhibits clonal deletion of highly pathogenic autoreactive t cells.	a number of in vitro studies have suggested that costimulatory molecules b7-1 and b7-2 and their receptor cd28 can promote clonal deletion, and limited in vivo studies have indicated that cd28 is involved in the clonal deletion of some t cells. however, the significance of b7-mediated clonal deletion in preventing autoimmune diseases has not been studied systematically. here we report that the perinatal blockade of b7-1 and b7-2 substantially inhibits the clonal deletion of t cells in the thymus ...	2002	11956287
identification of human homologues of the mouse mammary tumor virus receptor.	human breast tumors contain dna sequences with high homology to the mouse mammary tumor virus (mmtv) env gene. env encodes the membrane glycoprotein that binds to the mmtv receptor (mtvr) in mouse tissues and is required for infection. if humans become infected with mmtv, identification of a human mtvr might shed light on the mechanism of infection. here, we identified two human genes, mtvr1 and mtvr2, encoding proteins highly related to the mouse receptor. mtvr-related sequences were also detec ...	2002	11958456
proteasome inhibitors reduce luciferase and beta-galactosidase activity in tissue culture cells.	reporter enzymes are commonly used in cell biology to study transcriptional activity of genes. recently, reporter enzymes in combination with compounds that inhibit proteasome function have been used to study the effect of blocking transcription factor degradation on gene activation. while investigating the effect of proteasome inhibition on steroid receptor activation of the mouse mammary tumor virus (mmtv) promoter, we found that treatment with proteasome inhibitors enhanced glucocorticoid act ...	2002	11959849
viral late domains.		2002	11967285
atp-dependent mobilization of the glucocorticoid receptor during chromatin remodeling.	chromatin remodeling by the glucocorticoid receptor (gr) is associated with activation of transcription at the mouse mammary tumor virus (mmtv) promoter. we reconstituted this nucleoprotein transition with chromatin assembled on mmtv dna. the remodeling event was atp dependent and required either a nuclear extract from hela cells or purified human swi/snf. through the use of a direct interaction assay (magnetic bead pull-down), we demonstrated recruitment of human swi/snf to mmtv chromatin by gr ...	2002	11971959
testing mouse mammary tumor virus superantigen as adjuvant in cytotoxic t-lymphocyte responses against a melanoma tumor antigen.	cytotoxic t cells represent a powerful strategy for antitumor treatment. depending on the route of injection, an important role for cd4 t cell-mediated help was observed in the induction of this response. for this reason, we investigated whether induction of a ctl response to the hla-a2-restricted immunodominant peptide melanoma antigen melan-a was improved by using rvvs expressing the ctl-defined epitope alone or in combination with an sag. in the latter case, the few infected dendritic cells s ...	2002	11979434
ar possesses an intrinsic hormone-independent transcriptional activity.	recent research has highlighted the functional importance of chromatin structure in transcriptional regulation. we have used xenopus oocytes as a model system to investigate the action of ar in the context of chromatin. by manipulating the levels of ar expression, we have observed both agonist-dependent and -independent activation by ar. expression of ar at relatively low levels resulted in strong agonist-dependent activation, whereas high levels of ar also led to hormone-independent activation. ...	2002	11981028
the effect of dna-alkylating agents on gene expression from two integrated reporter genes in a mouse mammary tumor line.	a model system was developed to investigate the effects of dna alkylating agents on cellular gene expression. the cytomegalovirus immediate-early promoter (cmv) and the mouse mammary tumor virus promoter (mmtv) were coupled separately to the luciferase reporter gene and stably expressed in cultured cells. the change in luciferase activity was used as a measure of gene expression inhibition. seven well-characterized dna alkylating agents of varied dna adduct-forming ability were evaluated in this ...	2002	11984071
dependence of selective gene activation on the androgen receptor nh2- and cooh-terminal interaction.	the agonist-induced androgen receptor nh(2)- and cooh-terminal (n/c) interaction is mediated by the fxxlf and wxxlf nh(2)-terminal motifs. here we demonstrate that agonist-dependent transactivation of prostate-specific antigen (psa) and probasin enhancer/promoter regions requires the n/c interaction, whereas the sex-limited protein gene and mouse mammary tumor virus long terminal repeat do not. transactivation of psa and probasin response regions also depends on activation function 1 (af1) in th ...	2002	12000757
inducible dimerization of fgfr1: development of a mouse model to analyze progressive transformation of the mammary gland.	to develop an inducible and progressive model of mammary gland tumorigenesis, transgenic mice were generated with a mouse mammary tumor virus-long terminal repeat-driven, conditional, fibroblast growth factor (fgf)-independent fgf receptor (fgfr)1 (ifgfr1) that can be induced to dimerize with the drug ap20187. treatment of transgenic mice with ap20187 resulted in ifgfr1 tyrosine phosphorylation, increased proliferation, activation of mitogen-activated protein kinase and akt, and lateral budding. ...	2002	12011115
wnt3-wnt14b and wnt3a-wnt14 gene clusters (review).	wnt signals are transduced to beta-catenin - tcf pathway, jnk pathway, or ca2+-releasing pathway through wnt receptors. frat1, frat2, and par-1 are positive regulators of wnt - beta-catenin pathway. apc, axin, nkd1, nkd2, and strabismus (stb1, stb2) are negative regulators of wnt - beta-catenin pathway. here, biological significance of wnt3-wnt14b/wnt15 gene cluster (human chromosome 17q21) and wnt3a-wnt14 gene cluster (human chromosome 1q42) will be reviewed. total-amino-acid identity between w ...	2002	12011973
lack of ductal development in the absence of functional estrogen receptor alpha delays mammary tumor formation induced by transgenic expression of erbb2/neu.	expression of the mouse mammary tumor virus (mmtv) neu/erbb2 transgene in mice induces mammary tumors. to examine the effect of removing estrogen receptor alpha (eralpha) signaling on the ability of an mmtv-neu/erbb2 transgene to induce mammary tumors, the neu transgene was expressed in the eralpha knockout (alphaerko) mouse, which lacks functional eralpha. mmtv-neu females that lacked eralpha still developed mammary tumors; however, tumor onset was significantly delayed. this study indicates th ...	2002	12019156
proteasomal inhibition enhances glucocorticoid receptor transactivation and alters its subnuclear trafficking.	the ubiquitin-proteasome pathway regulates the turnover of many transcription factors, including steroid hormone receptors such as the estrogen receptor and progesterone receptor. for these receptors, proteasome inhibition interferes with steroid-mediated transcription. we show here that proteasome inhibition with mg132 results in increased accumulation of the glucocorticoid receptor (gr), confirming that it is likewise a substrate for the ubiquitin-proteasome degradative pathway. using the mous ...	2002	12024025
inhibition of breast tumor progression by systemic delivery of the maspin gene in a syngeneic tumor model.	maspin has been shown to possess tumor-suppressing activity against breast tumor growth and metastasis. to test the therapeutic value of the maspin gene (serpinb5) in breast cancer, we established a syngeneic breast tumor metastasis model. this model involved the implantation of mammary tumor cells orthotopically to mammary gland and allowed tumors to grow within the gland and become metastatic to other organs. the mammary tumor cells were initially isolated from mmtv-polyoma virus middle t tran ...	2002	12027560
glucocorticoid receptor domain requirements for chromatin remodeling and transcriptional activation of the mouse mammary tumor virus promoter in different nucleoprotein contexts.	the glucocorticoid receptor (gr) contains several activation domains, tau1 (af-1), tau2, and af-2, which were initially defined using transiently transfected reporter constructs. using domain mutations in the context of full-length gr, this study defines those domains required for activation of the mouse mammary tumor virus (mmtv) promoter in two distinct nucleoprotein configurations. a transiently transfected mmtv template with a disorganized, accessible chromatin structure was largely dependen ...	2002	12029095
activity of the gr in g2 and mitosis.	to elucidate the mechanisms mediating the reported transient physiological glucocorticoid resistance in g2/m cell cycle phase, we sought to establish a model system of glucocorticoid-resistant cells in g2. we synchronized various cell lines in g2 to measure dexamethasone (dex)-induced transactivation of either two endogenous promoters (rat tyrosine aminotransferase and mouse metallothionein i) or the mouse mammary tumor virus (mmtv) promoter stably or transiently transfected. to circumvent the n ...	2002	12040020
a novel, c-terminal dominant negative mutation of the gr causes familial glucocorticoid resistance through abnormal interactions with p160 steroid receptor coactivators.	primary cortisol resistance is a rare, inherited or sporadic form of generalized end-organ insensitivity to glucocorticoids. here, we report a kindred in which affected members had a heterozygous t to g base substitution at nucleotide 2373 of exon 9alpha of the gr gene, causing substitution of ile by met at position 747. this mutation was located close to helix 12, at the c terminus of the ligand-binding domain, which has a pivotal role in the formation of activation function (af)-2, a subdomain ...	2002	12050230
ectopic expression of the ets transcription factor er81 in transgenic mouse mammary gland enhances both urokinase plasminogen activator and stromelysin-1 transcription.	the pea3 group members pea3, er81 and erm, which are highly conserved transcription factors from the ets family, are over-expressed in metastatic mammary tumors. in the current study, we present the characterization of a transgenic mouse strain which over-expresses er81 in the mammary gland via the long terminal repeat of the mouse mammary tumor virus (ltr-mmtv). although six genotypically positive transgenic lines were identified, only one expressed the ectopic transcript with an exclusive expr ...	2002	12054346
loss of androgen receptor transcriptional activity at the g(1)/s transition.	androgens are essential for the differentiation, growth, and maintenance of male-specific organs. the effects of androgens in cells are mediated by the androgen receptor (ar), a member of the nuclear receptor superfamily of transcription factors. recently, transient transfection studies have shown that overexpression of cell cycle regulatory proteins affects the transcriptional activity of the ar. in this report, we characterize the transcriptional activity of endogenous ar through the cell cycl ...	2002	12055183
deletion of t cells bearing the v beta8.1 t-cell receptor following mouse mammary tumor virus 7 integration confers resistance to murine cerebral malaria.	plasmodium berghei anka induces a fatal neurological syndrome known as cerebral malaria (cm) in susceptible mice. host genetic elements are among the key factors determining susceptibility or resistance to cm. analysis of mice of the same h-2 haplotype revealed that mouse mammary tumor virus 7 (mtv-7) integration into chromosome 1 is one of the key factors associated with resistance to neurological disease during p. berghei anka infection. we investigated this phenomenon by infecting a series of ...	2002	12065512
blockade of tgf-beta inhibits mammary tumor cell viability, migration, and metastases.	tgf-betas are potent inhibitors of epithelial cell proliferation. however, in established carcinomas, autocrine/paracrine tgf-beta interactions can enhance tumor cell viability and progression. thus, we studied the effect of a soluble fc:tgf-beta type ii receptor fusion protein (fc:tbetarii) on transgenic and transplantable models of breast cancer metastases. systemic administration of fc:tbetarii did not alter primary mammary tumor latency in mmtv-polyomavirus middle t antigen transgenic mice. ...	2002	12070302
lifetime exposure to a soluble tgf-beta antagonist protects mice against metastasis without adverse side effects.	tgf-betas play diverse and complex roles in many biological processes. in tumorigenesis, they can function either as tumor suppressors or as pro-oncogenic factors, depending on the stage of the disease. we have developed transgenic mice expressing a tgf-beta antagonist of the soluble type ii tgf-beta receptor:fc fusion protein class, under the regulation of the mammary-selective mmtv-ltr promoter/enhancer. biologically significant levels of antagonist were detectable in the serum and most tissue ...	2002	12070308
prevalence of 52-kd and 60-kd ro/ss-a autoantibodies in japanese patients with polymyositis/dermatomyositis.	to determine the prevalence of 52-kd and 60-kd ro/ss-a antibodies in japanese patients with polymyositis/dermatomyositis, we examined serum samples from 61 patients with pm/dm, 10 patients with primary sjögren's syndrome, and 25 healthy control subjects. six serum samples possessed anti-ro/ss-a antibodies and were positive for anti-ro52, anti-ro60, or both. two reacted with both ro52 and ro60, and 4 reacted with ro52 alone. the results suggest that ro52 is the main antigen of anti-ro/ss-a antibo ...	2002	12077598
the role of phenylalanine-119 of the reverse transcriptase of mouse mammary tumour virus in dna synthesis, ribose selection and drug resistance.	phe-119 in the reverse transcriptase (rt) of mouse mammary tumour virus (mmtv) is homologous with tyr-115 in hiv type 1 (hiv-1) rt and to phe-155 in murine leukaemia virus (mlv) rt. by mutating these residues in hiv-1 and mlv rts (which are strict dna polymerases) the enzymes were shown to function also as rna polymerases. owing to the uniqueness of mmtv as a type b retrovirus, we have generated a phe-119-val mutant of mmtv rt to study the involvement of this residue in affecting the catalytic f ...	2002	12097136
jun dimerization protein 2 functions as a progesterone receptor n-terminal domain coactivator.	the progesterone receptor (pr) contains two transcription activation function (af) domains, constitutive af-1 in the n terminus and af-2 in the c terminus. af-2 activity is mediated by a hormone-dependent interaction with a family of steroid receptor coactivators (srcs). src-1 can also stimulate af-1 activity through a secondary domain that interacts simultaneously with the primary af-2 interaction site. other protein interactions and mechanisms that mediate af-1 activity are not well defined. b ...	2002	12101239
can mmtv exploit tlr4?	the recognition of microbial pathogens based on their molecular patterns is essential for host defense. recently, toll-like receptors have been shown not only to recognize viruses as well as bacteria and fungi, but also to trigger an efficient immune response. a recent publication proposed that the retrovirus mouse mammary tumor virus exploits the pattern-recognition receptor toll-like receptor 4 to achieve more efficient infection.	2002	12110201
trans-activation and repression properties of the novel nonsteroid glucocorticoid receptor ligand 2,5-dihydro-9-hydroxy-10-methoxy-2,2,4-trimethyl-5-(1-methylcyclohexen-3-y1)-1h-[1]benzopyrano[3,4-f]quinoline (a276575) and its four stereoisomers.	glucocorticoids are potent anti-inflammatory and immunosuppressant agents. however, they also produce serious side effects that limit their usage. it has been proposed that anti-inflammatory properties of glucocorticoids are caused mostly by repression of activator protein 1- and nuclear factor kappabeta-stimulated synthesis of inflammatory mediators, whereas most of their adverse effects are associated with trans-activation of genes involved with metabolic processes. our laboratories have sough ...	2002	12130681
inducible expression of fgf-3 in mouse mammary gland.	fibroblast growth factor-3 (fgf-3) is a crucial developmental regulator. aberrant activation of this gene by mouse mammary tumor virus insertion results in pregnancy-responsive mammary tumorigenesis. to characterize better fgf-3 function in postnatal mammary gland development and cancer initiation/progression, we used a mifepristone (ru486)-inducible regulatory system to express conditionally fgf-3 in the mammary epithelium of transgenic mice. ectopic overexpression of fgf-3 in pubescent mammary ...	2002	12169667
[effect of 5-azacytidine on expression of dna sequences homologous to env gene of murine mammary tumor virus in normal human lymphocytes].	expression of dna sequences, related to mmtv env gene, in peripheral blood lymphocytes, which was strictly specific for human mammary carcinoma, has been previously reported. these sequences (homologous to env gene site coding for mmtv gp52 envelope antigen) expressed in t cells can play the key role in virus infection transmission and propagation. in order to elucidate the possible routes of env mmtv-homologous sequences expression, we tried to induced it in donot t lymphocytes by various metho ...	2002	12180024
tef-1 transcription factors regulate activity of the mouse mammary tumor virus ltr.	the mouse mammary tumor virus long terminal repeat (ltr) is a potent transcriptional enhancer. we identified several putative binding sites for the tef-1 family of transcription factors (tef-1, rtef-1, dtef-1, and etf) in the proximal negative regulatory element of the ltr. gel mobility shift assays revealed strong tef-1 factor binding to one site using nuclear extracts from cv-1 cells and from the human breast cancer cell line mcf-7. mutation of this site increased basal activity of the ltr. in ...	2002	12207913
human breast cancer and lymphomas may share a common aetiology involving mouse mammary tumour virus (mmtv).	mouse mammary tumour virus (mmtv) causes breast tumours in mice, and has been implicated in the aetiology of murine lymphomas. several recent human studies have detected mmtv-env dna sequences in 30-40% of tumours from breast cancer patients but in less than 4% of normal breast tissue. mmtv dna has been detected in simultaneously diagnosed primary lymphoma and breast cancer tissue, suggesting mmtv may be involved in the aetiology of both breast cancer and lymphoma. we further hypothesize that if ...	2002	12208195
characterization of deoxyuridine 5'-triphosphate nucleotidohydrolase from trypanosoma cruzi.	we report the cloning and kinetic characterization of trypanosoma cruzi deoxyuridine 5'-triphosphate nucleotidohydrolase (dutpase) whose coding sequence was isolated by genetic complementation in escherichia coli. the deduced amino acid sequence was similar to leishmania major dutpase although it exhibits an amino acid insertion which is sensitive to protease inactivation. the catalytically active species of the enzyme is a dimer and a detailed kinetic characterization showed that it is highly s ...	2002	12208522
human immunodeficiency virus type 1 (hiv-1) accessory protein vpr induces transcription of the hiv-1 and glucocorticoid-responsive promoters by binding directly to p300/cbp coactivators.	the accessory vpr protein of human immunodeficiency virus type 1 (hiv-1) is a promiscuous activator of viral and cellular promoters. we report that vpr enhances expression of the glucocorticoid receptor-induced mouse mammary tumor virus (mmtv) promoter and of the tat-induced hiv-1 long terminal repeat promoter by directly binding to p300/cbp coactivators. in contrast, vpr does not bind to p/caf or to members of the p160 family of nuclear receptor coactivators, such as steroid receptor coactivato ...	2002	12208951
conditional over-expression of estrogen receptor alpha in a transgenic mouse model.	attempts to delineate the mechanisms of estrogen action have promoted the creation of several estrogen receptor alpha (eralpha) mouse models in the past decade. these traditional models are limited by the fact that the receptors are either absent or present throughout all stages of development. the purpose of this work was to develop a conditional transgenic model that would provide an in vivo method of controlling the spatial and temporal regulation of eralpha expression. the tetracycline respo ...	2002	12212839
glucocorticoids modulate transformation by v-src in a cell-specific manner.	in balb 3t3 murine fibroblasts infected with retroviruses carrying the v-src oncogene, treatment with the glucocorticoid hormone dexamethasone induces a 10-fold increase in the number of transformed foci and of anchorage-independent colonies. in contrast, in nih-3t3-infected cells the number of foci and of colonies growing in soft agar is considerably reduced by the addition of the hormone. the effect of dexamethasone on both balb 3t3 and nih 3t3 cells is dose-dependent and mediated by specific ...	2002	12213218
mouse transferrin receptor 1 is the cell entry receptor for mouse mammary tumor virus.	enveloped viruses enter cells by binding to their entry receptors and fusing with the membrane at the cell surface or after trafficking through acidic endosomal compartments. species-specific virus tropism is usually determined by these entry receptors. because mouse mammary tumor virus (mmtv) is unable to infect chinese hamster cells, we used phenotypic screening of the t31 mouse/hamster radiation hybrid panel to map the mmtv cell entry receptor gene and subsequently found that it is transferri ...	2002	12218182
weight-cycling decreases incidence and increases latency of mammary tumors to a greater extent than does chronic caloric restriction in mouse mammary tumor virus-transforming growth factor-alpha female mice.	multiple periods of caloric restriction (or fasting)/refeeding in rodents have had inconsistent effects on mammary tumor (mt) development. in the present study, the consequence of intermittent caloric restriction/refeeding resulting in weight-cycling was evaluated using an oncogene-induced mt mouse model. hybrid mouse mt virus-transforming growth factor alpha (mmtv-tgf-alpha)/lep(+)lep(ob) female mice were used. ad libitum-fed mice (n = 30) were fed american institute of nutrition (ain)-93m diet ...	2002	12223427
[the possibility of the retroviruses participation in human breast neoplasm induction].	the existence of retrovirus related to murine mammary tumor virus (mmtv) and specifically associated with mammary carcinoma has been suggested long ago. this review covers some papers published in the 70-80ies until now, containing evidence for this suggestion. in spite of a lack of direct proof of virus existence this problem still remains to be solved. there are some indications that both in man and in mice, peripheral blood lymphocytes participate in the circulation of the supposed viral agen ...	2002	12271725
[detection of murine mammary tumor virus (mmtv) env gene-like sequences in breast cancer from argentine patients].	in the last years research on the possible viral etiology of human breast cancer has been revised. previous studies have demonstrated the presence of a mouse mammary tumor virus (mmtv) env gene-like sequence in about 38% of breast cancers from american and italian women; these sequences are generally absent in other tumors and in normal mammary tissue. in the present study we have analyzed the presence of a 250-bp sequence of the mmtv env gene in breast cancer biopsies from argentine patients. t ...	2002	12325488
origin and progression of pregnancy-dependent mammary tumors induced by new mouse mammary tumor virus variants.	in order to study mechanisms of progression of mouse mammary tumor virus (mmtv)-induced pregnancy-dependent mammary lesions, we removed and serially transplanted 17 small tumors detected in mmtv-infected pregnant females. this gave rise to the same number of 'in vivo' tumor lines. hormone-dependency of the passages was determined by comparing tumor development in multiparous versus virgin hosts. we found that the first passages of most of these lesions (11/17) required pregnancy to grow. however ...	2002	12353808
celecoxib, a selective cyclooxygenase 2 inhibitor, protects against human epidermal growth factor receptor 2 (her-2)/neu-induced breast cancer.	cyclooxygenase 2 (her-2) (cox-2), an inducible form of cox, is overexpressed in her-2/neu-positive human breast cancers. the aim of this study was to determine whether celecoxib, a selective cox-2 inhibitor, protected against her-2/neu-induced experimental breast cancer. cox-2 protein was detected in breast carcinomas from mouse mammary tumor virus (mmtv)/neu mice. treatment with celecoxib (500 ppm) significantly reduced the incidence of mammary tumors in mmtv/neu mice (p = 0.003) and caused abo ...	2002	12359744
matrilysin (matrix metalloproteinase-7) selects for apoptosis-resistant mammary cells in vivo.	overexpression of the matrix metalloproteinase matrilysin (matrix metalloproteinase-7) in the mouse mammary gland promotes mammary hyperplasia and accelerates the onset of oncogene-induced mammary tumors. in cell culture models, acute exposure of cells coexpressing fas and fas ligand (fasl) to matrilysin induces apoptosis, whereas chronic exposure to matrilysin selects for apoptosis-resistant cells. we now demonstrate that matrilysin promotes resistance to apoptosis in vivo. matrilysin expressio ...	2002	12359768
differential activation of the ikappabalpha and mouse mammary tumor virus promoters by progesterone and glucocorticoid receptors.	the glucocorticoid and progesterone receptors (gr and pr) are structurally homologous and bind a common hormone response element (hre). the mechanisms by which receptors activate specific promoters when multiple steroids are present in a cell is a critical question in endocrinology. to investigate how co-existing steroid receptors regulate gene transcription, we have compared two hormone-responsive promoters in t47d/a1-2 human breast cancer cells expressing both the gr and pr. the promoters chos ...	2002	12361720
regions of mouse mammary tumor virus superantigen involved in interaction with the major histocompatibility complex class ii i-a molecule.	to study the major histocompatibility complex class ii i-e dependence of mouse mammary tumor virus (mmtv) superantigens, we constructed hybrids between the i-e-dependent mmtv(gr) and the i-e-independent mtv-7 superantigens and tested them in vivo. our results suggest that, although the c-terminal third mediates i-a interaction, additional binding sites are located elsewhere in the superantigen.	2002	12368363
soy isoflavones increase latency of spontaneous mammary tumors in mice.	soy protein, with and without isoflavones, is being added to foods by manufacturers in response to the food and drug administration (fda)-approved health claim for cardiovascular protection. furthermore, soy isoflavones are increasingly consumed by women in the united states as an alternative to hormone replacement therapy. the role of these phytoestrogens in breast cancer is controversial. although exposure of rodents to soy isoflavones during the perinatal period appears to reduce mammary canc ...	2002	12368416
antagonism of glucocorticoid receptor transactivity and cell growth inhibition by transforming growth factor-beta through ap-1-mediated transcriptional repression.	we have examined the interaction of the glucocorticoid receptor (gr) and transforming growth factor-beta (tgf-beta) signal pathways because of their mutual involvement in the regulation of cell growth, development and differentiation. most studies of this cross-talk event have focused on the effects of glucocorticoids (gcs) on tgf-beta responses. in this work, we show that tgf-beta can antagonize dexamethasone (dex)-mediated growth suppression in mouse fibrosarcoma l929 cells. tgf-beta also repr ...	2002	12379279
perturbation of beta1-integrin function in involuting mammary gland results in premature dedifferentiation of secretory epithelial cells.	to study the mechanism of beta1-integrin function in vivo, we have generated transgenic mouse expressing a dominant negative mutant of beta1-integrin under the control of mouse mammary tumor virus (mmtv) promoter (mmtv-beta1-cyto). mammary glands from mmtv-beta1-cyto transgenic females present significant growth defects during pregnancy and lactation and impaired differentiation of secretory epithelial cells at the onset of lactation. we report herein that perturbation of beta1-integrin function ...	2002	12388754
the specific anti-cancer activity of green tea (-)-epigallocatechin-3-gallate (egcg).	the effect of the green tea polyphenol-(-)epigallocatechin-3-gallate (egcg) was tested in cultures of normal and transformed nih-patm ras fibroblasts. in this system transformation can be induced at will by the addition of dexamethasone, which induces the expression of h- ras by activating the mammary tumor virus long terminal repeat (mmtv-ltr) promoter. this facilitates a reliable comparison of the susceptibility of normal and transformed cells to egcg. it has been shown that egcg inhibited the ...	2002	12395181
mouse mammary tumor-like env gene as a molecular marker for breast cancer?		2002	12397656
chlorpromazine inhibits the glucocorticoid receptor-mediated gene transcription in a calcium-dependent manner.	antipsychotic drugs can modulate transcription factors and also nuclear receptors, but their action on glucocorticoid receptors (gr)-members of the steroid/thyroid hormone receptor family has not been studied so far. in the present study we investigated effects of various antipsychotics on the glucocorticoid-mediated gene transcription in fibroblast cells, stably transfected with a mouse mammary tumor virus promoter (lmcat cells). chlorpromazine (3-100 microm) inhibited the corticosterone-induce ...	2002	12423673
mammary stem cell repertoire: new insights in aging epithelial populations.	the proliferative lifespan of mammary stem cells was examined in serially transplanted clonal-dominant epithelial populations. five successive transplant generations were done. the epithelial cell number in each outgrowth expands approximately 500-fold in nulliparous hosts and approximately 10000-fold in impregnated hosts. despite this, all resulting mammary outgrowths showed lineal identity with the original. growth senescence was observed in some implants beginning at the third generation in i ...	2002	12425957
initiation site binding protein and the initiator-like promoter element of mouse mammary tumor virus.	the mouse mammary tumor virus (mmtv) promoter contains an element near its transcription initiation site that is recognized by a protein termed initiation site binding protein (isbp). spacing between the tata box and the isbp site is important for mmtv promoter function, as altered spacing results in heterogeneity in start site selection in vitro and in vivo. the sequence of the isbp site is related to initiator elements common in many rna polymerase ii promoters. however, binding of partially p ...	2002	12429527
wnt and fgf gene clusters (review).	mouse mammary tumor virus (mmtv) is a retrovirus, activating wnt genes (wnt1/int-1, wnt3/int-4, wnt10b), fgf genes (fgf3/int-2, fgf4, fgf8) and other genes (notch4/int-3, eif3s6/int-6) due to proviral integration. among 19 wnt genes, wnt3 and wnt14b genes are clustered in human chromosome 17q21, wnt3a and wnt14 in human chromosome 1q42, wnt10a and wnt6 in human chromosome 2q35, and wnt10b and wnt1 in human chromosome 12q13. among 22 fgf genes, fgf19, fgf4 and fgf3 genes are clustered in human ch ...	2002	12429977
expression of a truncated brca1 protein delays lactational mammary development in transgenic mice.	to address the hypothesis that certain disease-associated mutants of the breast-ovarian cancer susceptibility gene brca1 have biological activity in vivo, we have expressed a truncated brca1 protein (trbrca1) in cell-lines and in the mammary gland of transgenic mice. immunofluorescent analysis of transfected cell-lines indicates that trbrca1 is a stable protein and that it is localized in the cell cytoplasm. functional analysis of these cell-lines indicates that expression of trbrca1 confers an ...	2002	12437078
the retinoid x receptor-selective retinoid, lgd1069, prevents the development of estrogen receptor-negative mammary tumors in transgenic mice.	despite the effectiveness of the selective estrogen receptor (er) modulators in preventing er-positive breast cancer, chemopreventive agents still need to be developed for the prevention of er-negative breast cancers. the naturally occurring retinoids are promising agents for the prevention of human cancers but are too toxic for long-term chronic use. we previously demonstrated that the chemopreventive effects of the retinoids could be separated from the toxicity by using an rxr-selective retino ...	2002	12438218
protein kinase ck2 promotes aberrant activation of nuclear factor-kappab, transformed phenotype, and survival of breast cancer cells.	the her-2/neu oncogene, the second member of the epidermal growth factor (egf) receptor family, encodes a transmembrane tyrosine kinase receptor. overexpression of her-2/neu in approximately 30% of breast cancers is associated with poor overall survival. recently, we have found that her-2/neu activates nuclear factor (nf)-kappab via a phosphatidylinositol 3 kinase (pi3-k)-akt kinase signaling pathway in mouse mammary tumor virus (mmtv)-her-2/neu nf639 mouse breast cancer cells. surprisingly, the ...	2002	12438279
asymmetric binding of histone h1 stabilizes mmtv nucleosomes and the interaction of progesterone receptor with the exposed hre.	packaging of mouse mammary tumor virus (mmtv) promoter sequences in nucleosomes modulates access of dna binding proteins and influences the interaction among dna bound transcription factors. here we analyze the binding of histone h1 to mmtv mononucleosomes assembled with recombinant histones and study its influence on nucleosome structure and stability as well as on progesterone receptor (pr) binding to the hormone responsive elements (hres). the mmtv nucleosomes can be separated into three main ...	2002	12445785
dynamic behavior of transcription factors on a natural promoter in living cells.	through the use of photobleaching techniques, we examined the dynamic interaction of three members of the transcription apparatus with a target promoter in living cells. the glucocorticoid receptor (gr) interacting protein 1 (grip-1) exhibits a half maximal time for fluorescent recovery (tau(r)) of 5 s, reflecting the same rapid exchange as observed for gr. in contrast, the large subunit (rpb1) of rna polymerase ii (pol ii) required 13 min for complete fluorescence recovery, consistent with its ...	2002	12446572
heparin-binding epidermal growth factor-like growth factor stimulates androgen-independent prostate tumor growth and antagonizes androgen receptor function.	peptide growth factors have been implicated in progression of prostate cancer (pca) to the androgen-independent state; however, much of the evidence linking diffusible mitogens and survival factors to this process remains circumstantial. heparin-binding epidermal growth factor-like growth factor (hb-egf), a prostate stroma-derived factor, promotes survival, proliferation, and neuroendocrine differentiation of androgen-dependent lncap pca cells in vitro. to test whether sustained exposure to hb-e ...	2002	12446587
attenuation of glucocorticoid signaling through targeted degradation of p300 via the 26s proteasome pathway.	the effects of acetylation on gene expression are complex, with changes in chromatin accessibility intermingled with direct effects on transcriptional regulators. for the nuclear receptors, both positive and negative effects of acetylation on specific gene transcription have been observed. we report that p300 and steroid receptor coactivator 1 interact transiently with the glucocorticoid receptor and that the acetyltransferase activity of p300 makes an important contribution to glucocorticoid re ...	2002	12456802
genes involved in breast cancer progression: analysis of global changes in gene expression or retroviral tagging?		2002	12466111
acceleration of mouse mammary tumor virus-induced murine mammary tumorigenesis by a p53 172h transgene: influence of fvb background on tumor latency and identification of novel sites of proviral insertion.	we previously showed that a mammary-specific dominant-negative p53 transgene (wap-p53(172h)) could accelerate erbb2-induced mammary tumorigenesis in mice, but was not tumorigenic on its own. to identify other genes that cooperate with wap-p53(172h) in tumorigenesis, we performed mouse mammary tumor virus (mmtv) proviral mutagenesis. we derived f1, n2, and n4/n5 mice from p53(172h) transgenic fvb mice backcrossed onto mmtv+ c3h/he mice. results show the latency of mmtv tumorigenesis is correlated ...	2002	12466138
complex role of histone h1 in transactivation of mmtv promoter chromatin by progesterone receptor.	transcription from the mouse mammary tumor virus (mmtv) promoter can be induced by glucocorticoids or progestins. the corresponding receptors bind to a cluster of hormone responsive elements (hres) and activate the promoter by synergistic interactions with ubiquitous transcription factors, in particular nuclear factor 1 (nf1). synergism between hormone receptors and nf1 depends on the precise positioning of the promoter sequences on the surface of a histone octamer in chromatin, but how linker h ...	2002	12650697
embryonal mass and hormone-associated effects of pregnancy inducing a differential growth of four murine tumors.	a differential effect of pregnancy on the growth of subcutaneous implants of four murine tumors has been observed. two tumors lacking receptors for progesterone and estrogen [methylcholanthrene-induced fibrosarcoma (mc-c) and spontaneous lymphoid leukemia (lb)] exhibited slow kinetics throughout the course of pregnancy, although inhibition was stronger beyond day 10. on the other hand, one of two tumors bearing receptors for progesterone and estrogen [medroxyprogesterone (mpa)-induced mammary ad ...	2002	12549624
potential action of igf-1 and egf on androgen receptor nuclear transfer and transactivation in normal and cancer human prostate cell lines.	this work was designed to determine whether igf-1 and egf modulate nuclear transfer and transactivation of the androgen receptor (ar) in human prostate cell lines (pnt1a and du-145). we first characterized the igf-1 and egf receptors by ligand-binding assays with [125i] igf-1 and [125i] egf in a normal human prostate epithelial cell line, pnt1a. we then evaluated the effects of these growth factors on ar nuclear transfer and transcriptional activation in this cell line and in du-145, a human pro ...	2002	12573820
effect of moderate caloric restriction and/or weight cycling on mammary tumor incidence and latency in mmtv-neu female mice.	recently, we reported that intermittent caloric restriction-refeeding reduces mammary tumor (mt) incidence and extends latency in murine mammary tumor virus (mmtv)-transforming growth factor (tgf)-a mice to a greater extent than does chronic caloric restriction. here, this same weight-cycling protocol was applied to mmtv-neu female mice, which develop mts at a much younger age than do tgf-a mice. this study consisted of three experimental groups: mice fed an ain-93m diet ad libitum, mice intermi ...	2002	12734063
nuclear receptor coactivator p160 proteins enhance the hiv-1 long terminal repeat promoter by bridging promoter-bound factors and the tat-p-tefb complex.	we report that p160 nuclear receptor coactivators potentiate the transactivating activity of tat, the most potent virally encoded transactivator of hiv-1. one of the p160 proteins (grip1) is tethered to the hiv-1 long terminal repeat (ltr) through kappab-responsive elements, most likely via nf-kappab, with which it also associates through its coactivator motifs (lxxll motifs, "nr boxes"). indeed, the tat-stimulated kappab-defective hiv-1 ltr had a markedly impaired response to grip1, whereas nr ...	2002	11704662
opposite effects of clozapine and sulpiride on the lipopolysaccharide-induced inhibition of the gr-mediated gene transcription in fibroblast cells.	previously, we have found that some antipsychotic drugs are able to inhibit glucocorticoid receptor (gr)-mediated gene transcription. since these drugs are known not only to inhibit hypothalamic-pituitary-adrenal (hpa) axis activity, but also to modulate the immunological system, the aim of the present study was to compare the effect of sulpiride and clozapine on gr function under basal culture conditions and during activation by lipopolysaccharide (lps). the effect of clozapine and sulpiride al ...	2003	14730115
development of a high-performance reporter plasmid for detection of chemicals with androgenic activity.	a number of chemicals are present in the environment, and some synthetic chemicals may disrupt endocrine function of wild animals and humans. an effective procedure to screen chemicals for endocrine modulating activity has been needed to ensure the safety of chemicals, and the reporter gene assay technique may provide a powerful tool for screening endocrine-disrupting chemicals. we have developed a high-performance reporter plasmid that can trigger high androgen-dependent induction with high sel ...	2003	12734641
transformation of rodent fibroblasts by the jaagsiekte sheep retrovirus envelope is receptor independent and does not require the surface domain.	jaagsiekte sheep retrovirus (jsrv) is the etiological agent of a contagious lung cancer of sheep known as ovine pulmonary adenocarcinoma (opa). expression of the jsrv envelope protein (env) is sufficient to transform immortalized and primary fibroblasts, but the precise mechanisms of this process are not known. the cellular receptor for jsrv is hyaluronidase 2 (hyal-2), the product of a putative tumor suppressor gene that in humans maps to a chromosomal region frequently deleted in the developme ...	2003	12743291
chromatin remodeling by nuclear receptors.	the eukaryotic genome is structurally organized into nucleosomes to form chromatin, which regulates gene expression, in part, by controlling the accessibility of regulatory factors. when packaged as chromatin, many promoters are transcriptionally repressed, thus reducing the access of transcription factors to their binding sites. however, nuclear receptors (nrs) are a group of transcription factors that have the ability to access their binding sites in this repressive chromatin structure. nuclea ...	2003	12743713
the fk506-binding immunophilin fkbp51 is transcriptionally regulated by progestin and attenuates progestin responsiveness.	fkbp51 and fkbp52 are large molecular weight fk506-binding immunophilins that have diverse biochemical functions. best studied is the role that they play as components of steroid hormone receptors. differential display and gene array screens have identified fkbp51 as a progestin-inducible gene. here we demonstrate progestin enhancement of fkbp51 mrna and protein in t-47d cells. fkbp51 mrna and protein levels were increased 3-fold by 20 nm r5020. induction of fkbp51 mrna was unaffected by 1 micro ...	2003	12746298
targeted expression of the dominant-negative prolactin receptor in the mammary gland of transgenic mice results in impaired lactation.	the f3-short form of the rat prl receptor (f3-sprlr) form acts as a dominant negative inhibitor in vitro. we have developed a transgenic mouse model in which the rat f3-sprlr was expressed in mammary epithelium under the control of the mouse mammary tumor virus promoter. two lines of mice were characterized and shown to express the transgene in the mammary gland. no developmental abnormalities or differences from wild-type littermates were observed on the basis of size, activity, or fertility. m ...	2003	12746331
progesterone and glucocorticoid receptors recruit distinct coactivator complexes and promote distinct patterns of local chromatin modification.	it is well established that steroid receptor function requires interaction with coactivators. however, the mechanisms through which steroid receptors elicit precise assembly of coactivator complexes and the way the steroid activation signal is transduced remain elusive. using a t47d cell line stably integrated with a mouse mammary tumor virus-chloramphenicol acetyltransferase (mmtv-cat) reporter, we demonstrate that specific steroid receptors exhibit preferential recruitment of src-1 family coac ...	2003	12748280
pyv-mt-induced parotid gland hyperplasia as detected by altered lectin reactivity is not modulated by inducible nitric oxide deficiency.	the parotid gland was one of the first organs recognised to be sensitive to the transforming effects of polyomavirus. this study examines parotid gland pathology in mice expressing the polyomavirus middle t (pyv-mt) under the control of the mouse mammary tumour virus long terminal repeat (mmtv-ltr) to (1) demonstrate the utility of this model for studying premalignant disease; (2) identify early lesions by lectin staining and (3) determine effects of the inducible nitric oxide synthase (inos) in ...	2003	12749913
myeloid cell expansion elicited by the progression of spontaneous mammary carcinomas in c-erbb-2 transgenic balb/c mice suppresses immune reactivity.	transgenic female mice expressing the transforming rat oncogene c-erbb-2 (her-2/neu) under the mouse mammary tumor virus (mmtv) promoter (balb-neut) spontaneously develop mammary carcinomas with a progression resembling that of human breast cancer. in these mice, activating antitumor immunotherapy fails to induce t cell-mediated cytotoxicity, suggesting a suppression of the immune response. we found a direct correlation between tumor multiplicity and an increased proportion of gr-1+ (ly6g)/mac-1 ...	2003	12750171
hormonal and dietary modulation of mammary carcinogenesis in mouse mammary tumor virus-c-erbb-2 transgenic mice.	exogenous and dietary estrogens have been associated with modification of breast cancer risk. mammary cancer model systems can be used to explore interactions between specific transgenes, and hormonal and dietary factors. transgenic mice bearing the rat wild-type erbb-2 gene were used to study the effects of short-term hormonal exposure [17beta-estradiol (e2) or tamoxifen] or a soy meal diet on mammary carcinogenesis. in mice fed a casein diet, mammary tumors developed at an earlier age after sh ...	2003	12750262
immunotherapy of spontaneous mammary carcinoma with fusions of dendritic cells and mucin 1-positive carcinoma cells.	the tumour-associated antigen mucin 1 (muc1) is a multifunctional protein involved in protection of mucous membranes, signal transduction, and modulation of the immune system. more than 70% of cancers overexpress muc1, making muc1 a potential target for immunotherapy. in the present study, muc1 transgenic mice were crossed with syngeneic strains that express the polyomavirus middle-t oncogene (pymt) driven by the mouse mammary tumour virus promoter long-terminal repeat (mmtv-ltr). the resultant ...	2003	12757626
interleukin-6 differentially regulates androgen receptor transactivation via pi3k-akt, stat3, and mapk, three distinct signal pathways in prostate cancer cells.	the effects of il-6 on prostate cancer cells are well documented yet remain controversial. some reports suggested that il-6 could promote prostate cancer cell growth, while others showed that il-6 could repress prostate cancer cell growth. here, we systemically examined various il-6 signaling pathways in prostate cancer cells and found that il-6 could go through at least three distinct pathways to modulate the functions of androgen receptor (ar), a key transcriptional factor to control the prost ...	2003	12763015
the mature reverse transcriptase molecules in virions of mouse mammary tumor virus possess protease-derived sequences.	our efforts to express in bacteria the enzymatically active reverse transcriptase (rt) of mouse mammary tumor virus (mmtv) have shown that the rt is active only after adding 27 amino acid residues, which are derived from the end of the pro gene, to the amino-terminus of the rt (biochem, j. (1998) 329, 579-587). in the present study we have tested whether the mature rt found in virions is also fused to protease-derived sequences. to this end, we have analyzed the rt molecules in virions of mmtv b ...	2003	12788639
the mouse mammary tumor virus-like env gene sequence is not detectable in breast cancer tissue of austrian patients.	the mammary mouse tumor virus (mmtv) has been related to human breast cancer in previous studies, but these have yielded contradictory results. an mmtv env gene-like sequence was detectable in a relatively high proportion (38%) of human breast cancer tissues. the aim of this study was to determine the proportion of this 660 bp mmtv env gene-like sequence in a population of austrian breast cancer patients. we performed pcr, repeat pcr, and nested pcr. we did not find any exogenous mmtv env gene s ...	2003	12792764
mmtv-related env sequences in human breast tumor.		2003	12794768
transforming growth factor beta signaling impairs neu-induced mammary tumorigenesis while promoting pulmonary metastasis.	the influence of transforming growth factor beta (tgf-beta) signaling on neu-induced mammary tumorigenesis and metastasis was examined with transgenic mouse models. we generated mice expressing an activated tgf-beta type i receptor or dominant negative tgf-beta type ii receptor under control of the mouse mammary tumor virus promoter. when crossed with mice expressing activated forms of the neu receptor tyrosine kinase that selectively couple to the grb2 or shc signaling pathways the activated ty ...	2003	12808151
the role of ink4a/arf in erbb2 mammary gland tumorigenesis.	most human tumors display inactivation of the p53 and the p16(ink4)/prb pathway. the ink4a/alternative reading frame (arf) locus encodes the p16(ink4a) and p14(arf) (murine p19(arf)) proteins. p16(ink4a) is deleted in 40-60% of breast cancer cell lines, and p16(ink4a) inactivation by dna methylation occurs in < or =30% of human breast cancers. in mice genetically heterozygous for p16(ink4a) or ink4a/arf, predisposition to specific tumor types is enhanced. ink4a/arf(+/-) mice have increased e mic ...	2003	12810676
activation of beta-catenin in prostate epithelium induces hyperplasias and squamous transdifferentiation.	the wnt/beta-catenin signaling pathway is critical for normal mammalian development, the specification of epidermal cells and neoplastic transformation of intestinal epithelium. however, precise molecular information regarding cell-specific responses to beta-catenin signaling has been limited. this question was addressed using a mouse model in which exon 3 of the beta-catenin gene was deleted in several cell types with loxp-mediated recombination utilizing a cre transgene under control of the mo ...	2003	12813461
t cell receptor revision does not solely target recent thymic emigrants.	cd4(+)vbeta5(+) t cells enter one of two tolerance pathways after recognizing a peripherally expressed superantigen encoded by an endogenous retrovirus. one pathway leads to deletion, while the other, termed tcr revision, results in cellular rescue upon expression of an alternate tcr that no longer recognizes the tolerogen. tcr revision requires the rearrangement of novel tcr beta-chain genes and depends on recombinase-activating gene (rag) expression in peripheral t cells. in line with recent f ...	2003	12817002
l-carnitine: a nutritional modulator of glucocorticoid receptor functions.	l-carnitine is an essential nutrient with a major role in cellular energy production. there is evidence that, at high doses, l-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. to explore the molecular basis of this effect, we tested the influence of l-carnitine on glucocorticoid receptor-alpha (gralpha) functions. millimolar concentrations of l-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [3h ...	2003	12824292
does a betaretrovirus infection trigger primary biliary cirrhosis?	patients with primary biliary cirrhosis develop progressive ductopenia associated with the production of antimitochondrial antibodies that react with a protein aberrantly expressed on biliary epithelial cells and peri-hepatic lymph nodes. although no specific microbe has been identified, it is thought that an infectious agent triggers this autoimmune liver disease in genetically predisposed individuals. previous serologic studies have provided evidence to suggest a viral association with primary ...	2003	12832623