| overexpression of the colony-stimulating factor (csf-1) and/or its receptor c-fms in mammary glands of transgenic mice results in hyperplasia and tumor formation. | a number of recent studies have suggested that the colony-stimulating factor (csf-1) and its receptor c-fms may be involved in the development of mammary glands during lactation and breast cancer. to study the role of csf-1 or its receptor in initiation of mammary tumorigenesis, we have generated two independent lines of transgenic mice that overexpress either csf-1 or c-fms under the control of the mouse mammary tumor virus promoter. mammary glands of the virgin csf-1 transgenic mice show incre ... | 2004 | 15205327 |
| brca1 inactivation induces p27(kip1)-dependent cell cycle arrest and delayed development in the mouse mammary gland. | one common characteristic of breast cancers arising in carriers of the predisposition gene brca1 is a loss of expression of the cdk inhibitor p27(kip1) (p27), suggesting that p27 interacts epistatically with brca1. to investigate this relationship, we examined expression of p27 in mice expressing a dominant negative allele of brca1 (mmtv-trbr) in the mammary gland. while these mice rarely develop tumors, they showed a 50% increase in p27 protein and a delay in mammary gland development associate ... | 2004 | 15208652 |
| fgf10 is an oncogene activated by mmtv insertional mutagenesis in mouse mammary tumors and overexpressed in a subset of human breast carcinomas. | mouse mammary tumor virus (mmtv) infection causes a high incidence of murine mammary carcinomas by insertion of its proviral dna in the genome of mammary epithelial cells. retroviral insertion can activate flanking proto-oncogenes by a process called insertional mutagenesis. by sequencing the dna adjacent to mmtv proviral insertions in mammary tumors from balb/c mice infected with c3h-mmtv, we have found a common mmtv insertion site in the fgf10 locus. rt-pcr studies showed that fgf10 is express ... | 2004 | 15208658 |
| validation: the new challenge for pathology. | modern pathologists have been challenged to "validate" mouse models of human cancer. validation requires matching of morphological attributes of the model to human disease. computers can assist in the validation process. however, adequate controlled, computer-readable vocabularies that can match terms do not currently exist in mouse pathology. further, current standard diagnostic terminologies do not include the new concepts discussed here such as pathway pathology and mammary intraepithelial ne ... | 2004 | 15209401 |
| a single amino acid change in the first zinc finger of the dna binding domain of the glucocorticoid receptor regulates differential promoter selectivity. | mammalian species are well known to differ in their sensitivity to glucocorticoids, but the molecular basis for this difference remains largely uncharacterized. to address this issue, the transcriptional activity of the mouse and human glucocorticoid receptor (gr) was analyzed on two model glucocorticoid-responsive promoters. mouse gr (mgr) displayed unique promoter discrimination in response to a range of glucocorticoids, with enhanced activity on a simple glucocorticoid response element (gre)- ... | 2004 | 15220338 |
| metastasis-associated protein 1 deregulation causes inappropriate mammary gland development and tumorigenesis. | emerging data suggest that metastasis-associated protein 1 (mta1) represses ligand-dependent transactivation functions of estrogen receptor-alpha in cultured breast cancer cells and that mta1 is upregulated in human breast tumors. however, the role of mta1 in tumorigenesis in a physiologically relevant animal system remains unknown. to reveal the role of mta1 in mammary gland development, transgenic mice expressing mta1 under the control of the mouse mammary tumor virus promoter long terminal re ... | 2004 | 15226262 |
| mouse mammary tumor-like virus is associated with p53 nuclear accumulation and progesterone receptor positivity but not estrogen positivity in human female breast cancer. | the purpose is to compare the presence of proteins with known associations with breast cancer-progesterone receptor (pgr), estrogen receptor, and p53, with the prevalence of mouse mammary tumor virus (mmtv)-like dna sequences in human female breast cancers. | 2004 | 15240531 |
| calmodulin-mediated activation of akt regulates survival of c-myc-overexpressing mouse mammary carcinoma cells. | c-myc-overexpressing mammary epithelial cells are proapoptotic; their survival is strongly promoted by epidermal growth factor (egf). we now demonstrate that egf-induced akt activation and survival in transgenic mouse mammary tumor virus-c-myc mouse mammary carcinoma cells are both calcium/calmodulin-dependent. akt activation is abolished by the phospholipase c-gamma inhibitor u-73122, by the intracellular calcium chelator bapta-am, and by the specific calmodulin antagonist w-7. these results im ... | 2004 | 15247222 |
| mood stabilizers inhibit glucocorticoid receptor function in lmcat cells. | mood stabilizers block some central effects induced by stress and glucocorticosteroids; however, little is known about interaction of these drugs with glucocorticoid receptor function. in the present study, we evaluated effects of lithium, valproate and carbamazepine on glucocorticoid receptor-mediated gene expression in mouse fibroblast cells (l929), stably transfected with mouse mammary tumor virus (mmtv)-chloramphenicol acetyltransferase reporter plasmid (lmcat cells). treatment of lmcat cell ... | 2004 | 15249158 |
| mammary tumor heterogeneity in wt-erbb-2 transgenic mice. | phenotypic and biological heterogeneity was studied in a single transgenic mouse model to determine the level of biological variance. we analyzed 1,258 tumors from 417 mmtv-wt-erbb-2 transgenic mice, subdivided by casein or soy-based dietary randomization and hormonal treatment. variance in tumor histologic features, growth pattern, invasion, metastases, and multi-focality were detected in untreated and treated mice. ninety-three percent (1,174/1,258) of tumors had the solid growth pattern widel ... | 2004 | 15253274 |
| effect of high fat diet on body weight and mammary tumor latency in mmtv-tgf-alpha mice. | the role of high fat diets in breast cancer/mammary tumor (mt) development is controversial. this may be partially attributable to variable effects of high fat diets on body weight. here, we used a moderately high fat diet (32.5% fat calories) expected to cause obesity in most mice, but predicted to result in some mice remaining in the weight range of mice fed the low fat diet (11% fat calories). this provided the opportunity to compare mice fed the high fat diet exhibiting different body weight ... | 2004 | 15254485 |
| progression from normal breast pathology to breast cancer is associated with increasing prevalence of mouse mammary tumor virus-like sequences in men and women. | mouse mammary tumor virus (mmtv)-like sequences have been found in up to 40% of breast cancer samples but in <2% of normal breast tissue samples from australian women studied by our group. screening of a larger and more diverse cohort of female breast cancer samples has now shown a correlation of mmtv-like sequences with the severity (grade) of breast cancer. thirty-two percent (43 of 136) of female breast cancer samples were positive for mmtv-like sequences when screened using pcr. a significan ... | 2004 | 15256443 |
| modulation of notch signaling elicits signature tumors and inhibits hras1-induced oncogenesis in the mouse mammary epithelium. | deregulation of notch signaling, which normally affects a broad spectrum of cell fates, has been implicated in various neoplastic conditions. here we describe a transgenic mouse model, which demonstrates that expression of a constitutively active form of the notch1 receptor in the mammary epithelium induces the rapid development of pregnancy/lactation-dependent neoplasms that consistently exhibit a characteristic histopathological pattern. these signature tumors retain the ability to respond to ... | 2004 | 15277242 |
| transcriptionally competent chromatin assembled with exogenous histones in a yeast whole cell extract. | we describe a cell-free chromatin assembly system derived from the yeast saccharomyces cerevisiae, which efficiently packages dna into minichromosomes in a reaction dependent on exogenous core histones and an atp-regenerating system. both supercoiled and relaxed plasmid dna serve as templates for nucleosomal loading in a gradual process that takes at least 6 h for completion at 30 degrees c. micrococcal nuclease digestion of the assembled minichromosomes displays an extended nucleosomal ladder w ... | 2004 | 15282330 |
| parity-induced mammary epithelial cells facilitate tumorigenesis in mmtv-neu transgenic mice. | using a cre-lox-based genetic labeling technique, we have recently discovered a parity-induced mammary epithelial subtype that is abundant in nonlactating and nonpregnant, parous females. these mammary epithelial cells serve as alveolar progenitors in subsequent pregnancies, and transplantation studies revealed that they possess features of multipotent progenitors such as self-renewal and the capability to contribute to ductal and alveolar morphogenesis. here, we report that these cells are the ... | 2004 | 15286714 |
| notch in mammary gland development and breast cancer. | notch signaling has been implicated in many processes including cell fate determination and oncogenesis. in mice, the notch1 and notch4 genes are both targets for insertion and rearrangement by the mouse mammary tumor virus and these mutations promote epithelial mammary tumorigenesis. moreover, expression of a constitutively active form of notch4 in mammary epithelial cells inhibits epithelial differentiation and leads to tumor formation in this organ. these data implicate the notch pathway in b ... | 2004 | 15288259 |
| progression of pregnancy-dependent mouse mammary tumors after long dormancy periods. involvement of wnt pathway activation. | mouse mammary tumor virus (la) induces pregnancy-dependent mammary tumors that progress toward autonomy. here we show that in virgin females, pregnancy-dependent tumor transplants are able to remain dormant for up to 300 days. during that period, these tumors synthesize dna, express high levels of estrogen and progesterone receptors (er+pr+) and are able to resume growth after hormone stimulation. surprisingly, in a subsequent transplant generation, all these tumors are fully able to grow in vir ... | 2004 | 15289324 |
| inhibition of glucocorticoid receptor-mediated transcriptional activation by p38 mitogen-activated protein (map) kinase. | tumor necrosis factor (tnf) promotes certain immune and inflammatory responses, whereas glucocorticoids exert immunosuppressive and anti-inflammatory actions. we show that tnf treatment produced a modest inhibition of glucocorticoid receptor (gr)-mediated transcriptional activation of a mouse mammary tumor virus (mmtv) promoter-driven luciferase construct in hela cells. the mitogen-activated protein (map) kinases, p38 and c-jun n-terminal kinase (jnk), are important mediators of target gene acti ... | 2004 | 15292225 |
| notch signaling in mammary development and oncogenesis. | with the discovery of an activated notch oncogene as a causative agent in mouse mammary tumor virus induced breast cancer in mice, the potential role for notch signaling in normal and pathological mammary development was revealed. subsequently, notch receptors have been found to regulate normal development in many organ systems. in addition, inappropriate notch signaling has been implicated in cancer of several tissues in humans and animal model systems. here we review important features of the ... | 2004 | 15300010 |
| lack of immunological or molecular evidence for a role of mouse mammary tumor retrovirus in primary biliary cirrhosis. | recent observations, including a pilot clinical trial, have suggested that a human mouse mammary tumor virus (mmtv) causes primary biliary cirrhosis (pbc). we attempted to confirm such data. | 2004 | 15300582 |
| increasing evidence for a human breast carcinoma virus with geographic differences. | an early immunologic study suggesting that a virus similar to the mouse mammary tumor virus (mmtv) was associated highly with breast carcinoma in tunisian patients, compared with patients in the united states, led the authors to examine different breast carcinoma populations by using more current molecular techniques. | 2004 | 15305401 |
| single-molecule recognition imaging microscopy. | atomic force microscopy is a powerful and widely used imaging technique that can visualize single molecules and follow processes at the single-molecule level both in air and in solution. for maximum usefulness in biological applications, atomic force microscopy needs to be able to identify specific types of molecules in an image, much as fluorescent tags do for optical microscopy. the results presented here demonstrate that the highly specific antibody-antigen interaction can be used to generate ... | 2004 | 15314231 |
| investigation of three new mouse mammary tumor cell lines as models for transforming growth factor (tgf)-beta and neu pathway signaling studies: identification of a novel model for tgf-beta-induced epithelial-to-mesenchymal transition. | this report describes the isolation and characterization of three new murine mammary epithelial cell lines derived from mammary tumors from mmtv (mouse mammary tumor virus)/activated neu + tbetarii-as (transforming growth factor [tgf]-beta type ii receptor antisense rna) bigenic mice (bri-jm01 and bri-jm05 cell lines) and mmtv/activated neu transgenic mice (bri-jm04 cell line). | 2004 | 15318933 |
| experimental manipulation of radiographic density in mouse mammary gland. | extensive mammographic density in women is associated with increased risk for breast cancer. mouse models provide a powerful approach to the study of human diseases, but there is currently no model that is suited to the study of mammographic density. | 2004 | 15318935 |
| unliganded thyroid hormone receptor-beta1 represses liver x receptor alpha/oxysterol-dependent transactivation. | the thyroid hormone receptor (tr) and liver x receptor (lxr)-alpha are members of the nuclear hormone receptor family and are ligand-dependent transcription factors. among the promoter target genes, tr and lxr recognize the t3 response element and lxr response element (lxre), respectively. because t3 response elements and lxres have similar configurations, referred to as direct repeat 4, we investigated the possibility of cross-talk between the two ligand-dependent signal transduction pathways. ... | 2004 | 15319359 |
| selective recruitment of p160 coactivators on glucocorticoid-regulated promoters in schwann cells. | in the nervous system, glucocorticoid hormones play a major role during development and throughout life. we studied the mechanisms of action of the glucocorticoid receptor (gr) and its interactions with p160 coactivator family members [steroid receptor coactivator (src)-1 (a and e), src-2 and src-3] in mouse schwann cells (msc80). we found that the three p160s were expressed in msc80 cells. we have shown by functional overexpression and rna interference experiments that the recruitment of these ... | 2004 | 15331759 |
| vitamin d receptor status alters mammary gland morphology and tumorigenesis in mmtv-neu mice. | the vitamin d(3) receptor (vdr) is a ligand-dependent transcription factor implicated in regulation of cell cycle, differentiation and apoptosis of both normal and transformed cells derived from mammary gland. in these studies we examined whether vdr status altered mammary gland morphology or transformation in the well-characterized mmtv-neu transgenic model of breast cancer. we demonstrate that vdr protein is highly expressed in neu-positive epithelial cells of preneoplastic lesions, establishe ... | 2004 | 15333467 |
| epithelial mesenchymal transition is a characteristic of hyperplasias and tumors in mammary gland from mmtv-cripto-1 transgenic mice. | epithelial-mesenchymal transition (emt) facilitates migration and invasion of epithelial tumor cells. cripto-1 (cr-1), a member of the epidermal growth factor-cfc protein family increases migration of cells in vitro. here the expression of molecular markers and signaling molecules characteristic of emt were assessed in mammary gland hyperplasias and tumors from mice expressing the human cr-1 transgene by the mmtv promoter (mmtv-cr-1) and in mouse mammary epithelial cell line hc-11 overexpressing ... | 2004 | 15334661 |
| partial agonist/antagonist properties of androstenedione and 4-androsten-3beta,17beta-diol. | androgens play important endocrine roles in development and physiology. here, we characterize activities of two "andro" prohormones, androstenedione (a-dione) and 4-androsten-3beta,17beta-diol (a-diol) in mda-mb-453 (mda) and lncap cells. a-dione and a-diol, like cyproterone acetate, were partial agonists of transfected mouse mammary tumor virus (mmtv) and endogenous prostate-specific antigen (psa) promoters. different from bicalutamide but similar to cpa, both are inducers of lncap cell prolife ... | 2004 | 15336702 |
| role of f-box protein betatrcp1 in mammary gland development and tumorigenesis. | the f-box protein betatrcp1 controls the stability of several crucial regulators of proliferation and apoptosis, including certain inhibitors of the nf-kappab family of transcription factors. here we show that mammary glands of betatrcp1(-/-) female mice display a hypoplastic phenotype, whereas no effects on cell proliferation are observed in other somatic cells. to investigate further the role of betatrcp1 in mammary gland development, we generated transgenic mice expressing human betatrcp1 tar ... | 2004 | 15340078 |
| global expression profiling identifies signatures of tumor virulence in mmtv-pymt-transgenic mice: correlation to human disease. | fvb/n-tg (mmtv-pymt)(634mul)-transgenic mice develop multifocal mammary tumors with a high incidence of pulmonary metastasis. we have demonstrated previously that mammary tumors derived from transgene-positive f1 progeny in particular inbred strains display altered latency, tumor growth rates, and metastatic rates when compared with the fvb/nj homozygous parent. to identify genes with expression that might be critical in modifying the biological behavior of mmtv-pymt tumors, we performed a detai ... | 2004 | 15342376 |
| using atomic force microscopy to study nucleosome remodeling on individual nucleosomal arrays in situ. | in eukaryotes, genomic processes like transcription, replication, repair, and recombination typically require alterations in nucleosome structure on specific dna regions to operate. atp-dependent nucleosome remodeling complexes provide a major mechanism for carrying out such alterations in vivo. to learn more about the action of these important complexes, we have utilized an atomic force microscopy in situ technique that permits comparison of the same individual molecules before and after activa ... | 2004 | 15345572 |
| bax regulates c-myc-induced mammary tumour apoptosis but not proliferation in mmtv-c-myc transgenic mice. | the expression of the proto-oncogene c-myc is frequently deregulated, via multiple mechanisms, in human breast cancers. deregulated expression of c-myc contributes to mammary epithelial cell transformation and is causally involved in mammary tumorigenesis in mmtv-c-myc transgenic mice. c-myc is known to promote cellular proliferation, apoptosis, genomic instability and tumorigenesis in several distinct tissues, both in vivo and in vitro. expression of the proapoptotic regulatory gene bax is redu ... | 2004 | 15354213 |
| generation of a conditional knockout allele for the janus kinase 2 (jak2) gene in mice. | to study biologically relevant functions of the janus kinase 2 (jak2) in multiple cytokine and hormone receptor signal transduction pathways, we generated a conditional knockout (floxed) allele of this gene by placing loxp sites around the first coding exon of jak2. homozygous floxed animals developed normally and exhibited no phenotypic abnormalities. the conversion of the floxed allele into a null mutation was achieved by transmitting the targeted allele through the female germline of mmtv-cre ... | 2004 | 15354294 |
| mouse mammary tumor virus-like viral infection and human breast cancer. | | 2004 | 15355888 |
| clonal isolation of different strains of mouse mammary tumor virus-like dna sequences from both the breast tumors and non-hodgkin's lymphomas of individual patients diagnosed with both malignancies. | in a previous study, we had detected the presence of mouse mammary tumor virus (mmtv)-like envelope (env) gene sequences in both the breast tumors and non-hodgkin's lymphoma tissue of two of our breast tumor patients who had been diagnosed simultaneously with both malignancies. the aim of this study was to determine if mmtv-like dna sequences are present in the breast tumors and non-hodgkin's lymphomas of additional patients suffering from both malignancies and if so to characterize these sequen ... | 2004 | 15355890 |
| caveolin-1 gene disruption promotes mammary tumorigenesis and dramatically enhances lung metastasis in vivo. role of cav-1 in cell invasiveness and matrix metalloproteinase (mmp-2/9) secretion. | caveolin-1 (cav-1) is the principal structural component of caveolae membrane domains in non-muscle cells, including mammary epithelia. there is now clear evidence that caveolin-1 influences the development of human cancers. for example, a dominant-negative mutation (p132l) in the cav-1 gene has been detected in up to 16% of human breast cancer samples. however, the exact functional role of caveolin-1 remains controversial. mechanistically, in cultured cell models, cav-1 is known to function as ... | 2004 | 15355971 |
| characterization of smubp-2 as a mouse mammary tumor virus promoter-binding protein. | a cdna encoding a rat smubp-2 has been cloned from a lambdagt11 library by south-western blot screening using a 50-bp tannic acid responsive element [j. biol. chem. 273 (1998) 12499] of the mouse mammary tumor virus (mmtv) promoter region as a probe. the full-length cdna encodes a protein with a predicted size of 108 kda. northern blot analysis revealed that the gene expression of smubp-2 is comparatively high in testis, moderate in brain, and low in other tissues. the recombinant smubp-2 protei ... | 2004 | 15358184 |
| elevated expression of the tumor suppressing protein p53 is associated with the presence of mouse mammary tumor-like env gene sequences (mmtv-like) in human breast cancer. | mouse mammary tumor virus (mmtv) has a proven role in breast carcinogenesis in wild mice and genetically susceptible laboratory inbred mice. the carcinogenic characteristics of this virus are enhanced by estrogen and other steroid hormones. mmtv-like envelope gene sequences, with 95% homology to mmtv have been identified in approximately 40% of breast cancers in us, australian and argentinian women. the presence of such sequences indicates the presence of a replication competent mmtv-like virus ... | 2004 | 15377846 |
| nuclear factor 1 and octamer transcription factor 1 binding preset the chromatin structure of the mouse mammary tumor virus promoter for hormone induction. | when the mouse mammary tumor virus (mmtv) is integrated into the genome of a mammalian cell, its long terminal repeat (ltr) harbors six specifically positioned nucleosomes. transcription from the mmtv promoter is regulated by the glucocorticoid hormone via the glucocorticoid receptor (gr). the mechanism of the apparently constitutive nucleosome arrangement has remained unclear. previous in vitro reconstitution of nucleosome(s) on small segments of the mmtv ltr suggested that the dna sequence was ... | 2004 | 15381691 |
| ikaros null mice display defects in t cell selection and cd4 versus cd8 lineage decisions. | previous evidence suggested that the hemopoietic-specific nuclear factor ikaros regulates tcr signaling thresholds in mature t cells. in this study, we test the hypothesis that ikaros also sets tcr signaling thresholds to regulate selection events and cd4 vs cd8 lineage determination in developing thymocytes. ikaros null mice were crossed to three lines of tcr-transgenic mice, and positive selection, negative selection, and cd4 vs cd8 lineage decisions were analyzed. mice expressing a polyclonal ... | 2004 | 15383578 |
| production of a secreted glycoprotein from an inducible promoter system in a perfusion bioreactor. | the primary advantage of an inducible promoter expression system is that production of the recombinant protein can be biochemically controlled, allowing for the separation of unique growth and production phases of the culture. during the growth phase, the culture is rapidly grown to high cell density prior to induction without the extra metabolic burden of exogenous protein production, thus minimizing the nonproductive period of the culture. induction of the culture at high cell density ensures ... | 2004 | 15458323 |
| the human glucocorticoid receptor (hgr) beta isoform suppresses the transcriptional activity of hgralpha by interfering with formation of active coactivator complexes. | the human glucocorticoid receptor (hgr) beta, a splicing variant of the classic receptor hgralpha, functions as a dominant-negative inhibitor of hgralpha. we explored the mechanism(s) underlying this effect of hgrbeta by evaluating the interactions of this isoform with known steroid receptor coactivators. we found that hgrbeta suppressed the transcriptional activity of both activation function (af)-1 and af-2 of hgralpha, indicating that hgrbeta may exert its dominant-negative effect by affectin ... | 2005 | 15459252 |
| comparative analysis of inducible expression systems in transient transfection studies. | ectopic protein expression in mammalian cells is a valuable tool to analyze protein functions. increasingly, inducible promoters are being used for regulated gene expression. here, we compare expression maxima, induction rates, and "leakiness" of the following promoter systems: (i) two tetracycline-responsive tet systems (tet-on, tet-off), (ii) the glucocorticoid-responsive mouse mammary tumor virus promoter (mmtvprom), (iii) the ecdysone-inducible promoter (ecp), and (iv) the t7 promoter/t7 rna ... | 2004 | 15464949 |
| a paracrine loop between tumor cells and macrophages is required for tumor cell migration in mammary tumors. | invasion of tumor cells into the surrounding connective tissue and blood vessels is a key step in the metastatic spread of breast tumors. although the presence of macrophages in primary tumors is associated with increased metastatic potential, the mechanistic basis for this observation is unknown. using a chemotaxis-based in vivo invasion assay and multiphoton-based intravital imaging, we show that the interaction between macrophages and tumor cells facilitates the migration of carcinoma cells i ... | 2004 | 15466195 |
| haploid inactivation of the amplified-in-breast cancer 3 coactivator reduces the inhibitory effect of peroxisome proliferator-activated receptor gamma and retinoid x receptor on cell proliferation and accelerates polyoma middle-t antigen-induced mammary tumorigenesis in mice. | the amplified-in-breast cancer 3 (aib3) is a nuclear receptor coactivator amplified and overexpressed in human breast cancers. aib3(-/-) mice die during gestation, whereas aib3(+/-) mice exhibit normal development. here, we demonstrate that aib3 protein is mainly located in the nuclei of mammary epithelial cells and tumor cells and its levels are elevated in mammary epithelial cells at middle pregnant stage and in mammary tumor cells. to examine whether aib3 reduction affects mammary tumorigenes ... | 2004 | 15466215 |
| mmtv-trbrca1 mice display strain-dependent abnormalities in vaginal development. | the breast cancer susceptibility gene brca1 encodes a large multi-functional protein which is implicated as a caretaker of the genome, through its role in regulation of dna damage response pathways, including apoptosis. here we show that in mice expressing a dominant-negative brca1 transgene on a balb/c background, vaginal entrance remodeling is inhibited, and that the incidence of this phenotype is increased on a p53 +/- genotype. given that this developmental process is mediated primarily by a ... | 2004 | 15470641 |
| reduced metastasis of transgenic mammary cancer in urokinase-deficient mice. | a prominent phenotype of plasmin deficiency in mice is reduced metastasis in the mmtv-pymt transgenic breast cancer model. proteolytically active plasmin is generated from inactive plasminogen by one of 2 activators, upa or tpa. we now find that upa deficiency alone significantly reduces metastasis >7-fold in the mmtv-pymt model. we studied a cohort of 55 mmtv-pymt transgenic mice, either upa-deficient or wild-type controls. tumor incidence, latency, growth rate and final primary tumor burden we ... | 2005 | 15472905 |
| development of androgen- and estrogen-responsive bioassays, members of a panel of human cell line-based highly selective steroid-responsive bioassays. | we have established highly sensitive and specific androgen and estrogen reporter cell lines which we have named ar (androgen receptor) and eralpha (estrogen receptor alpha) calux (chemically activated luciferase expression), respectively. both bioassays are member of a panel of calux reporter cell lines derived from the human u2-os osteosarcoma cell line, all using highly selective reporter constructs based with a basal promoter element linked to multimerized response elements, allowing efficien ... | 2005 | 15483189 |
| 11-deoxycorticosterone is a potent agonist of the rainbow trout (oncorhynchus mykiss) mineralocorticoid receptor. | the teleost fish are thought to lack the mineralocorticoid hormone aldosterone but possess mineralocorticoid receptor (mr) homologs. here we describe the characterization of two rainbow trout (oncorhynchus mykiss) mrs, called rtmra and rtmrb. the open reading frame of rtmra cdna encoded a protein of 1041 amino acids. the rtmrb predicted protein sequence is similar, differing in only 10 amino acids in the nonconserved a/b domain and lacking a three-amino acid insertion between the two zinc finger ... | 2005 | 15486226 |
| selective loss of akr1c1 and akr1c2 in breast cancer and their potential effect on progesterone signaling. | progesterone plays an essential role in breast development and cancer formation. the local metabolism of progesterone may limit its interactions with the progesterone receptor (pr) and thereby act as a prereceptor regulator. selective loss of akr1c1, which encodes a 20alpha-hydroxysteroid dehydrogenase [20alpha-hsd (ec 1.1.1.149)], and akr1c2, which encodes a 3alpha-hydroxysteroid dehydrogenase [3alpha-hsd (ec 1.1.1.52)], was found in 24 paired breast cancer samples as compared with paired norma ... | 2004 | 15492289 |
| toward multiplexing the application of solvent accessibility probes for the investigation of rna three-dimensional structures by electrospray ionization-fourier transform mass spectrometry. | multiple solvent accessibility probes can be applied simultaneously to investigate the three-dimensional structure of complex rna substrates when electrospray ionization-fourier transform mass spectrometry (esi-ftms) is employed in place of polyacrylamide gel electrophoresis (page). we show that classic chemical probes, such as dimethylsulfate, kethoxal, and 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate, can be combined in probing mixtures designed to assess the full sp ... | 2004 | 15494143 |
| sensitive in vitro test systems to determine androgenic/antiandrogenic activity. | we report on the establishment of one transgenic and two endogenous reporter gene assays to determine androgenic/antiandrogenic activity. a transient transactivation assay was developed in cos-7 african green monkey kidney cells. three plasmids were co-transfected by electroporation: the human androgen receptor expression vector psg5ar, the reporter gene vector pmamneoluc, expressing luciferase under the control of the mouse mammary tumor virus (mmtv) promotor containing 4 hormone responsive ele ... | 2004 | 15497179 |
| uv laser cross-linking: a real-time assay to study dynamic protein/dna interactions during chromatin remodeling. | we describe the use of laser ultraviolet (uv) cross-linking to study the interaction of transcription factors with in vitro assembled chromatinized dna templates in real time. because the laser source delivers a high density of photons in a single ns pulse, the cross-linking reaction is completed in less than 1 microseconds, allowing the investigator to freeze rapid dynamic changes in protein-dna interactions. using this approach, we have sampled the dynamic equilibrium of the glucocorticoid rec ... | 2004 | 15507594 |
| dressa: biosensing of dioxin and dioxin-like chemicals using secreted alkaline phosphatase. | in this article, we describe a highly sensitive biosensing system, dressa, for detection of dioxin and dioxin-like chemicals. tandem copies of the dioxin-responsive element (dre) fused to a minimal viral promoter were subcloned into an expression plasmid upstream of a secreted alkaline phosphatase (seap) gene. when murine hepatoma cell line hepa-1c1c7 was stably transfected with this construct, established sensor clones secreted seap following stimulation with 2,3,7,8-tetrachlorodibenzo-p-dioxin ... | 2004 | 15519573 |
| dna instructed displacement of histones h2a and h2b at an inducible promoter. | regulation of gene expression requires dynamic changes in chromatin, but the nature of these changes is not well understood. here, we show that progesterone treatment of cultured cells leads to recruitment of progesterone receptor (pr) and swi/snf-related complexes to mouse mammary tumor virus (mmtv) promoter, accompanied by displacement of histones h2a and h2b from the nucleosome containing the receptor binding sites, but not from adjacent nucleosomes. pr recruits swi/snf to mmtv nucleosomes in ... | 2004 | 15525516 |
| mouse mammary tumor virus-like rna transcripts and dna are found in affected cells of human breast cancer. | identifiable risk factors for the development of breast cancer include age, diet, family history, and lifetime estrogen exposure. an infectious agent (mouse mammary tumor virus; mmtv) is known to cause murine breast tumors and may be involved in the pathogenesis of human disease. multiple studies have detected mmtv-like sequences in 30 to 60% of breast cancer samples and up to 1.8% of samples from normal breast. using in situ pcr of mmtv-like sequences of formalin-fixed, paraffin-embedded breast ... | 2004 | 15534103 |
| proteotypic classification of spontaneous and transgenic mammary neoplasms. | mammary tumors in mice are categorized by using morphologic and architectural criteria. immunolabeling for terminal differentiation markers was compared among a variety of mouse mammary neoplasms because expression of terminal differentiation markers, and especially of keratins, provides important information on the origin of neoplastic cells and their degree of differentiation. | 2004 | 15535849 |
| an autocrine mechanism for constitutive wnt pathway activation in human cancer cells. | autocrine wnt signaling in the mouse mammary tumor virus model was the first identified mechanism of canonical pathway activation in cancer. in search of this transformation mechanism in human cancer cells, we identified breast and ovarian tumor lines with upregulation of the uncomplexed transcriptionally active form of beta-catenin without mutations afflicting downstream components. extracellular wnt antagonists frp1 and dkk1 caused a dramatic downregulation of beta-catenin levels in these tumo ... | 2004 | 15542433 |
| chromatin-dependent e1a activity modulates nf-kappab rela-mediated repression of glucocorticoid receptor-dependent transcription. | the role of chromatin-dependent regulatory mechanisms in the repression of glucocorticoid-dependent transcription from the murine mammary tumor virus (mmtv) promoter by p65 and e1a was investigated by using chromatin and transiently transfected reporters. the p65 rela subunit of nf-kappab represses mmtv expression on either transient or integrated reporters. in contrast, the viral oncoprotein e1a represses a transient but not an integrated mmtv. e1a repression is attenuated by chromatin, suggest ... | 2005 | 15556937 |
| cyclooxygenase-2 inhibitor induces apoptosis in breast cancer cells in an in vivo model of spontaneous metastatic breast cancer. | cyclooxygenase-2 (cox-2) inhibitors are rapidly emerging as a new generation of therapeutic drug in combination with chemotherapy or radiation therapy for the treatment of cancer. the mechanisms underlying its antitumor effects are not fully understood and more thorough preclinical trials are needed to determine if cox-2 inhibition represents a useful approach for prevention and/or treatment of breast cancer. the purpose of this study was to evaluate the growth inhibitory mechanism of a highly s ... | 2004 | 15561779 |
| untying the fiv frameshifting pseudoknot structure by ms3d. | the structure of the putative feline immunodeficiency virus (fiv) ribosomal frameshifting pseudoknot (pk) has been investigated by a mass spectrometric three-dimensional (ms3d) approach, which involves the application of established solvent-accessibility probes and chemical crosslinkers with detection by electrospray ionization (esi) fourier transform mass spectrometry (ftms). regardless of their size, probed substrates can be treated with ribonucleases and analyzed by esi-ftms to obtain the cor ... | 2005 | 15567411 |
| patients with primary biliary cirrhosis make anti-viral and anti-mitochondrial antibodies to mouse mammary tumor virus. | | 2004 | 15578536 |
| parity-induced mouse mammary epithelial cells are pluripotent, self-renewing and sensitive to tgf-beta1 expression. | a parity-induced mammary population, marked by beta-galactosidase expression conditionally activated through cre-lox recombinase originates in wap-cre/rosa-lox-stop-lox-lacz (wap-cre/rosa-lacz) female mice during pregnancy, lactation and involution. during subsequent pregnancies, these parity-induced mammary epithelial cells (pi-mec) proliferated to produce new secretory acini composed of secretory luminal cells and myoepithelium. in serial transplantation assays, pi-mec were able to self-renew ... | 2005 | 15580303 |
| insertional polymorphisms of endogenous herv-k113 and herv-k115 retroviruses in breast cancer patients and age-matched controls. | endogenous retroviral sequences resulting from ancient retrovirus infections of germline cells account for up to 8% of the human genome. most of these sequences are highly truncated, have been altered by mutations, and do not encode functional genes. however, some members of the human endogenous retrovirus (herv)-k family are remarkably intact and display high genetic homology to mouse mammary tumor virus (mmtv), a retrovirus causing breast cancer in mice. two full-length hervs (k113 and k115) h ... | 2004 | 15588344 |
| effects of lipopolysaccharide and chlorpromazine on glucocorticoid receptor-mediated gene transcription and immunoreactivity: a possible involvement of p38-map kinase. | it has been hypothesized that dysregulations of the immune system and glucocorticoid receptor (gr) function are involved in the pathogenesis of schizophrenic disorders. previously, we found that among antipsychotics, chlorpromazine most potently inhibited gr function under in vitro conditions. in order to study a role of the some immune system mediators in this process, we investigated the effect of lipopolysaccharide (lps) on chlorpromazine-induced changes in gr-mediated gene transcription in f ... | 2004 | 15589393 |
| 3',5'-cyclic adenosine monophosphate response element-binding protein and ccaat enhancer-binding protein are dispensable for insulin inhibition of phosphoenolpyruvate carboxykinase transcription and for its synergistic induction by protein kinase a and glucocorticoids. | phosphoenolpyruvate carboxykinase (pepck) transcription is induced by camp/protein kinase a (pka) and glucocorticoids [dexamethasone (dex)] and is inhibited by insulin to regulate blood glucose. recent reports suggested that ccaat enhancer binding protein (c/ebp) binding to the pepck camp response element (cre) plays a role in dex induction and that insulin-induces inhibitory forms of c/ebpbeta to inhibit transcription. here, we assessed the roles of cre-binding protein (creb) and c/ebp factors ... | 2004 | 15604115 |
| early changes in protein expression detected by mass spectrometry predict tumor response to molecular therapeutics. | biomarkers that predict therapeutic response are essential for the development of anticancer therapies. we have used matrix-assisted laser desorption/ionization mass spectrometry (maldi-ms) to directly analyze protein profiles in mouse mammary tumor virus/her2 transgenic mouse frozen tumor sections after treatment with the erbb receptor inhibitors osi-774 and herceptin. inhibition of tumor cell proliferation and induction of apoptosis and tumor reduction were predicted by a >80% reduction in thy ... | 2004 | 15604278 |
| molecular dynamics and nuclear receptor function. | the development of live cell and biochemical analysis methods has led to an increase in our understanding of the dynamic regulation of transcription. live single cell studies using photobleaching techniques indicate that many proteins have a high nuclear mobility. pioneering work using promoter array systems based on the lac operon or the mouse mammary tumor virus promoter enabled the study of chromatin structure, promoter occupancy and protein-chromatin interaction dynamics in relation to trans ... | 2005 | 15620544 |
| diet-induced obesity and mammary tumor development in mmtv-neu female mice. | obesity is a risk factor for postmenopausal breast cancer and is associated with shortened latency and/or increased mammary tumor (mt) incidence in animals. elevated body weight is usually associated with hormone-responsive tumors. in agreement with these data we previously showed that latency of hormone-responsive mts in mmtv-tgf-alpha mice with diet-induced obesity was significantly shortened. here, we used the same protocol to determine the impact of diet-induced obesity on estrogen receptor- ... | 2004 | 15623464 |
| presence of papillomavirus sequences in condylomatous lesions of the mamillae and in invasive carcinoma of the breast. | viruses including epstein-barr virus (ebv), a human equivalent of murine mammary tumour virus (mmtv) and human papillomavirus (hpv) have been implicated in the aetiology of human breast cancer. we report the presence of hpv dna sequences in areolar tissue and tumour tissue samples from female patients with breast carcinoma. the presence of virus in the areolar-nipple complex suggests to us a potential pathogenic mechanism. | 2004 | 15642157 |
| alphavirus replicon particles containing the gene for her2/neu inhibit breast cancer growth and tumorigenesis. | overexpression of the her2/neu gene in breast cancer is associated with an increased incidence of metastatic disease and with a poor prognosis. although passive immunotherapy with the humanized monoclonal antibody trastuzumab (herceptin) has shown some effect, a vaccine capable of inducing t-cell and humoral immunity could be more effective. | 2004 | 15642163 |
| contribution by faedo et al. (clin cancer res 2004;10:4417-4419). | | 2005 | 15671572 |
| localization of self-interacting domains within betaretrovirus gag polyproteins. | the betaretrovirus genus is characterized by the ability to preassemble immature capsids within the cytoplasm. for mason-pfizer monkey virus (m-pmv) this ability depends in part upon the unique internal scaffold domain (isd) within the p12 region of gag. in this study, we have further characterized the ability of m-pmv p12 to promote gag-gag interaction and have examined the gag polyprotein of the related mouse mammary tumor virus (mmtv) to potentially identify a region with equivalent function. ... | 2005 | 15680431 |
| cystic duct dilatations and proliferative epithelial lesions in mouse mammary glands upon keratin 5 promoter-driven overexpression of cyclooxygenase-2. | expression and pharmacological studies support a contribution of cyclooxygenase (cox)-2 to mammary gland tumorigenesis. in a recent transgenic study, mouse mammary tumor virus promoter-driven cox-2 expression in mouse mammary glands was shown to result in alveolar hyperplasia, dysplasia, and carcinomas after multiple rounds of pregnancy and lactation. in the study presented here, the effects of constitutive cox-2 overexpression in keratin 5-positive myoepithelial and luminal cells, driven by the ... | 2005 | 15681840 |
| mmtv env encodes an itam responsible for transformation of mammary epithelial cells in three-dimensional culture. | expression of immunoreceptor tyrosine-based activation motif (itam)-containing signaling proteins is normally restricted to hematopoietic tissues. the basal activity of itam-containing proteins is mediated through negative regulation by coreceptors restricted to hematopoietic tissues. we have identified an itam signaling domain encoded within the env gene of murine mammary tumor virus (mmtv). three-dimensional structures derived in vitro from murine cells stably transfected with mmtv env display ... | 2005 | 15684322 |
| from breast cancer immunobiology to her-2 dna vaccine and autoimmune sequelae. | the heterogeneous nature of breast cancer and the correlation of myeloid cell infiltration with accelerated tumor progression were recognized early in breast cancer immunology research using murine model systems induced by the mouse mammary tumor virus, chemical carcinogens or hormones. distinct cell lines established from a single mammary tumor attest to the challenges of controlling tumors with such complexity. here, we test the feasibility of controlling breast cancer by active vaccination ta ... | 2004 | 15687706 |
| atmospheric pressure maldi-ftms of normal and chemically modified rna. | atmospheric pressure (ap) maldi has been combined with fourier transform mass spectrometry (ftms) to obtain the unambiguous characterization of rna samples modified by solvent accessibility reagents used in structural studies of rna and protein-rna complexes. the formation of cation adducts typical of ms analysis of nucleic acids was effectively reduced by extensive washing of the anionic analytes retained onto the probe surface by strong interactions with a cationic layer of poly(diallyldimethy ... | 2005 | 15694770 |
| flash interacts with p160 coactivator subtypes and differentially suppresses transcriptional activity of steroid hormone receptors. | we previously reported that tumor necrosis factor alpha receptor- and fas-associated flash interacts with one of the p160 nuclear receptor coactivators, glucocorticoid receptor-interacting protein (grip) 1, at its nuclear receptor-binding (nrb) domain, and that inhibits the transcriptional activity of the glucocorticoid receptor (gr) by interfering with association of gr and grip1. here, we further examined the specificity of flash suppressive effect and the physical/functional interactions betw ... | 2004 | 15698540 |
| mouse mammary tumor virus and human breast cancer. | | 2005 | 15705914 |
| detection of the env mmtv-homologous sequences in mammary carcinoma patient intestine lymphoid tissue. | | 2004 | 15717597 |
| angiotensin ii and aldosterone regulate gene transcription via functional mineralocortocoid receptors in human coronary artery smooth muscle cells. | inhibition or blockade of the angiotensin-aldosterone system consistently decreases ischemic cardiovascular events in clinical trials. the steroid hormone aldosterone acts by binding to the mineralocorticoid receptor (mr), a ligand activated transcription factor that is a member of the nuclear hormone receptor superfamily. mr binds and is activated by aldosterone and cortisol with equal affinity, but mr activation by cortisol is diminished in tissues that express the cortisol-inactivating enzyme ... | 2005 | 15718497 |
| ron receptor signaling augments mammary tumor formation and metastasis in a murine model of breast cancer. | the tyrosine kinase receptor ron has been implicated in several types of cancer, including overexpression in human breast cancer. this is the first report describing the effect of ron signaling on tumorigenesis and metastasis in a mouse model of breast cancer. mice with a targeted deletion of the ron tyrosine kinase signaling domain (tk-/-) were crossed to mice expressing the polyoma virus middle t antigen (pmt) under the control of the mouse mammary tumor virus promoter. both pmt-expressing wil ... | 2005 | 15735014 |
| cross-talk between an activator of nuclear receptors-mediated transcription and the d1 dopamine receptor signaling pathway. | nuclear receptors are transcription factors that usually interact, in a ligand-dependent manner, with specific dna sequences located within promoters of target genes. the nuclear receptors can also be controlled in a ligand-independent manner via the action of membrane receptors and cellular signaling pathways. 5-tetradecyloxy-2-furancarboxylic acid (tofa) was shown to stimulate transcription from the mmtv promoter via chimeric receptors that consist of the dna binding domain of gr and the ligan ... | 2005 | 15740779 |
| ligand-specific dynamics of the progesterone receptor in living cells and during chromatin remodeling in vitro. | progesterone receptor (pr), a member of the nuclear receptor superfamily, is a key regulator of several processes in reproductive function. we have studied the dynamics of the interaction of pr with a natural target promoter in living cells through the use of fluorescence recovery after photobleaching (frap) analysis and also have characterized the dynamics of the interaction of pr with the mouse mammary tumor virus (mmtv) promoter reconstituted into chromatin in vitro. in photobleaching experim ... | 2005 | 15743833 |
| foxa1 binding to the mmtv ltr modulates chromatin structure and transcription. | novel binding sites for the forkhead transcription factor family member forkhead box a (foxa), previously referred to as hepatocyte nuclear factor 3 (hnf3), were found within the mouse mammary tumor virus long terminal repeat (mmtv ltr). the effect of foxa1 on mmtv ltr chromatin structure, and expression was evaluated in xenopus laevis oocytes. mutagenesis of either of the two main foxa binding sites showed that the distal site, -232/-221, conferred foxa1-dependent partial inhibition of glucocor ... | 2004 | 15748903 |
| promotion of mammary cancer development by tamoxifen in a mouse model of brca1-mutation-related breast cancer. | loss of full-length brca1 in mammary epithelial cells of the mouse mammary tumor virus (mmtv)-cre brca1 conditional exon 11 deletion mouse model results in the development of mammary adenocarcinomas with similar genetic changes to those found in human brca1-mutation-related breast cancers. we used this experimental model to evaluate the chemopreventive effect of tamoxifen on the development of mammary preneoplasia and adenocarcinoma. no protective effects of tamoxifen administration on mammary c ... | 2005 | 15750629 |
| vegf contributes to mammary tumor growth in transgenic mice through paracrine and autocrine mechanisms. | vascular endothelial growth factor (vegf) has been identified as a vascular permeability factor, angiogenic cytokine, and a survival factor. to address its role in mammary carcinogenesis, we used transgenic mice with human vegf(165) targeted to mammary epithelial cells under the control of the mouse mammary tumor virus (mmtv) promoter. metastatic mammary carcinomas were induced by mating the mmtv-vegf mice with mmtv-polyoma virus middle t-antigen (mt) mice to generate vegf/mt mice. tumor latency ... | 2005 | 15765121 |
| amino acid preferences for a critical substrate binding subsite of retroviral proteases in type 1 cleavage sites. | the specificities of the proteases of 11 retroviruses representing each of the seven genera of the family retroviridae were studied using a series of oligopeptides with amino acid substitutions in the p2 position of a naturally occurring type 1 cleavage site (val-ser-gln-asn-tyr pro-ile-val-gln; the arrow indicates the site of cleavage) in human immunodeficiency virus type 1 (hiv-1). this position was previously found to be one of the most critical in determining the substrate specificity differ ... | 2005 | 15767422 |
| a novel point mutation in the ligand-binding domain (lbd) of the human glucocorticoid receptor (hgr) causing generalized glucocorticoid resistance: the importance of the c terminus of hgr lbd in conferring transactivational activity. | glucocorticoid resistance is a rare, familial or sporadic condition characterized by partial end-organ insensitivity to glucocorticoids. the clinical spectrum of the condition is broad, ranging from completely asymptomatic to severe hyperandrogenism and/or mineralocorticoid excess. the molecular basis of glucocorticoid resistance has been ascribed to mutations in the human glucocorticoid receptor-alpha (hgralpha) gene, which impair one or more of the molecular mechanisms of gr action, thus alter ... | 2005 | 15769988 |
| effect of conditional knockout of the type ii tgf-beta receptor gene in mammary epithelia on mammary gland development and polyomavirus middle t antigen induced tumor formation and metastasis. | transforming growth factor-beta (tgf-beta) isoforms are growth factors that function physiologically to regulate development, cellular proliferation, and immune responses. the role of tgf-beta signaling in mammary tumorigenesis is complex, as tgf-beta has been reported to function as both a tumor suppressor and tumor promoter. to elucidate the role of tgf-beta signaling in mammary gland development, tumorigenesis, and metastasis, the gene encoding type ii tgf-beta receptor, tgfbr2, was condition ... | 2005 | 15781643 |
| human progesterone receptor displays cell cycle-dependent changes in transcriptional activity. | the human progesterone receptor (pr) contains multiple ser-pro phosphorylation sites that are potential substrates for cyclin-dependent kinases, suggesting that pr activity might be regulated during the cell cycle. using t47d breast cancer cells stably transfected with an mouse mammary tumor virus (mmtv) chloramphenicol acetyltransferase reporter (cat0) synchronized in different phases of the cell cycle, we found that pr function and phosphorylation is remarkably cell cycle dependent, with the h ... | 2005 | 15798179 |
| linking the ubiquitin-proteasome pathway to chromatin remodeling/modification by nuclear receptors. | over 25 years ago, eukaryotic cells were shown to contain a highly specific system for the selective degradation of short-lived proteins, this system is known as the ubiquitin-proteasome pathway. in this pathway, proteins are targeted for degradation by covalent modification by a small highly conserved protein named ubiquitin. ubiquitin-mediated degradation of regulatory proteins plays an important role in numerous cell processes, including cell cycle progression, signal transduction and transcr ... | 2005 | 15821097 |
| the retinoid x receptor-selective retinoid, lgd1069, down-regulates cyclooxygenase-2 expression in human breast cells through transcription factor crosstalk: implications for molecular-based chemoprevention. | retinoids and their derivatives can suppress the development of cancer in animals and in humans. we and others have shown that retinoid x receptor (rxr)-selective retinoids or "rexinoids" suppress the development of breast cancer in several animal models with minimal toxicity. lgd1069 (bexarotene) is a potent rxr-selective retinoid with reduced toxicity compared with naturally occurring retinoids. in this study, we investigated the expression of lgd1069-modulated biomarkers. we previously did cd ... | 2005 | 15833882 |
| adipocyte-derived collagen vi affects early mammary tumor progression in vivo, demonstrating a critical interaction in the tumor/stroma microenvironment. | the interactions of transformed cells with the surrounding stromal cells are of importance for tumor progression and metastasis. the relevance of adipocyte-derived factors to breast cancer cell survival and growth is well established. however, it remains unknown which specific adipocyte-derived factors are most critical in this process. collagen vi is abundantly expressed in adipocytes. collagen(-/-) mice in the background of the mouse mammary tumor virus/polyoma virus middle t oncogene (mmtv-py ... | 2005 | 15841211 |
| nuclear matrix binding regulates satb1-mediated transcriptional repression. | special at-rich binding protein 1 (satb1) originally was identified as a protein that bound to the nuclear matrix attachment regions (mars) of the immunoglobulin heavy chain intronic enhancer. subsequently, satb1 was shown to repress many genes expressed in the thymus, including interleukin-2 receptor alpha, c-myc, and those encoded by mouse mammary tumor virus (mmtv), a glucocorticoid-responsive retrovirus. satb1 binds to mars within the mmtv provirus to repress transcription. to address the ro ... | 2005 | 15851481 |
| inhibition of the 26s proteasome blocks progesterone receptor-dependent transcription through failed recruitment of rna polymerase ii. | in the present study, we investigated the involvement of protein degradation via the 26s proteasome during progesterone receptor (pr)-mediated transcription in t-47d cells containing a stably integrated mmtv-cat reporter construct (cat0 cells). progesterone induced cat and hsd11beta2 transcription while co-treatment with the proteasome inhibitor, mg132, blocked pr-induced transcription in a time-dependent fashion. mg132 treatment also inhibited transcription of beta-actin and cyclophilin, but no ... | 2005 | 15857753 |
| int6 expression can predict survival in early-stage non-small cell lung cancer patients. | the int6 gene was originally identified as a common insertion site for the mouse mammary tumor virus in virally induced mouse mammary tumors. recent studies indicate that int6 is a multifaceted protein involved in the regulation of protein translation and degradation through binding with three complexes: the eukaryotic translation initiation factor 3, the proteasome regulatory lid, and the constitutive photomorphogenesis 9 signalosome. this study aimed to investigate the prognostic role of int6 ... | 2005 | 15867213 |
| dietary (n-3) polyunsaturated fatty acids inhibit her-2/neu-induced breast cancer in mice independently of the ppargamma ligand rosiglitazone. | overexpression of human epidermal growth factor receptor 2 (her-2/neu) characterizes a molecular subtype of breast cancer associated with poor clinical outcome. preventive strategies for her-2/neu-positive breast cancer, which is often estrogen and progesterone receptor negative, remain undefined. activators of peroxisome proliferator-activated receptor gamma (ppargamma), a nuclear hormone receptor also expressed in breast cancer, hold potential as cancer prevention agents. ppargamma ligands inc ... | 2005 | 15867269 |
| overexpression of lmo4 induces mammary hyperplasia, promotes cell invasion, and is a predictor of poor outcome in breast cancer. | the zinc finger protein lmo4 is overexpressed in a high proportion of breast carcinomas. here, we report that overexpression of a mouse mammary tumor virus (mmtv)-lmo4 transgene in the mouse mammary gland elicits hyperplasia and mammary intraepithelial neoplasia or adenosquamous carcinoma in two transgenic strains with a tumor latency of 13-18 months. to investigate cellular processes controlled by lmo4 and those that may be deregulated during oncogenesis, we used rna interference. down-regulati ... | 2005 | 15897450 |