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R D Cardiff

Publications and source records attributed to R D Cardiff.

At least 37 records · Page 2Linked to original sources
PubMed2000

Impact of progesterone receptor on cell-fate decisions during mammary gland development.

Mammary epithelium contains lineage-limited progenitors that give rise to cells that form distinct morphological structures, ducts vs. lobules, depending on the endocrine status of the female. Progesterone signaling through progesterone receptor (PR) is essential for lobulo-alveolar development that accompanies pregnancy, but not for ductal growth accompanying puberty. PR exists in two molecular forms, A and B, and an imbalance in the native ratio of the two isoforms can lead to alterations in PR signaling. Indeed, as we reported previously, in transgenic mice carrying additional A form of PR, mammary development is abnormal, characterized by excessive lateral ductal branching. This suggests that alterations in PR signaling may have important consequences to mammary development, particularly with regard to ductal vs. alveolar growth. To test this further, we created transgenic mice carrying additional B form of PR and report that mammary development in these mice is also abnormal, characterized by inappropriate alveolar growth. More importantly, these mammary glands, on serial transplantation, undergo a premature arrest in ductal growth without any alteration in the potential for lobulo-alveolar growth. Such an arrest in ductal growth does not occur with transgenics carrying additional A form of PR. These studies, therefore, provide strong evidence to indicate that PR signaling may be of paramount importance for appropriate cell-fate decisions during normal mammary development, and also that this requires a regulated expression of the two isoforms.

Animals↗
PubMed2000

Amplification of the neu/erbB-2 oncogene in a mouse model of mammary tumorigenesis.

The neu (c-erbB-2, Her-2) protooncogene is amplified and overexpressed in 20-30% of human breast cancers. Although transgenic mouse models have illustrated the role of Neu in the induction of mammary tumors, Neu expression in these models is driven by a strong viral promoter of questionable relevance to the human disease. To ascertain whether expression of activated Neu under the control of the endogenous promoter in the mammary gland could induce mammary tumors we have generated mice that conditionally express activated Neu under the transcriptional control of the intact endogenous Neu promoter. Expression of oncogenic neu in the mammary gland resulted in accelerated lobulo-alveolar development and formation of focal mammary tumors after a long latency period. However, expression of activated Neu under the normal transcriptional control of the endogenous promoter was not sufficient for the initiation of mammary carcinogenesis. Strikingly, all mammary tumors bear amplified copies (2-22 copies) of the activated neu allele relative to the wild-type allele and express highly elevated levels of neu transcript and protein. Thus, like human erbB-2-positive breast tumors, mammary tumorigenesis in this mouse model requires the amplification and commensurate elevated expression of the neu gene.

Animals↗
PubMed2000

The mammary pathology of genetically engineered mice: the consensus report and recommendations from the Annapolis meeting.

NIH sponsored a meeting of medical and veterinary pathologists with mammary gland expertise in Annapolis in March 1999. Rapid development of mouse mammary models has accentuated the need for definitions of the mammary lesions in genetically engineered mice (GEM) and to assess their usefulness as models of human breast disease. The panel of nine pathologists independently reviewed material representing over 90% of the published systems. The GEM tumors were found to have: (1) phenotypes similar to those of non-GEM; (2) signature phenotypes specific to the transgene; and (3) some morphological similarities to the human disease. The current mouse mammary and human breast tumor classifications describe the majority of GEM lesions but unique morphologic lesions are found in many GEM. Since little information is available on the natural history of GEM lesions, a simple morphologic nomenclature is proposed that allows direct comparisons between models. Future progress requires rigorous application of guidelines covering pathologic examination of the mammary gland and the whole animal. Since the phenotype of the lesions is an essential component of their molecular pathology, funding agencies should adopt policies ensuring careful morphological evaluation of any funded research involving animal models. A pathologist should be part of each research team.

Animals↗
PubMed2000

Genetically engineered mouse models of mammary intraepithelial neoplasia.

Foci of atypical mammary epithelium have been associated with breast cancer in many species including mouse and man. The advent of targeted genomics has led to the creation of numerous genetically engineered mice (GEM) which display focal atypical lesions associated with mammary cancer. Some early lesions in GEM have a remarkable morphological similarity to pre-cancers in humans. While the malignant potential of atypical foci have been thoroughly documented in the non-GEM by tissue transplantation, a review of the literature reveals that precursor lesions in GEM remain incompletely described and only partially documented. Their validation as appropriate models of human breast preneoplasia awaits classical transplantation studies. Here, we review the literature characterizing early lesions of GEM models of mammary cancer, discuss the principles of the Focality, Atypia, and Association and present an introduction of mammary transplantation for model Validation.

Animals↗
PubMed2000

Mammary cancer in humans and mice: a tutorial for comparative pathology. The CD-ROM.

This article introduces a CD-ROM containing whole-mount and histological images of normal growth and development of both the mouse mammary gland and the human breast. It also covers nonneoplastic lesions and neoplasias in both species including a catalog of lesions in genetically engineered mice. Instructions, with examples, on techniques such as whole-mount preparation, immunohistochemistry, in situ hybridization, and common histological stains are provided. The images are based on full-scale 1996 x 1640 pixel images at 300 pixels/ inch and are annotated. Every genetically engineered model has one or more accompanying citations. Tables are provided for orientation and organization. The CD includes zoom capabilities, a search engine, and a help mode.

Animals↗
PubMed1999

A single targeted Ets2 allele restricts development of mammary tumors in transgenic mice.

Heterozygous female mice carrying a targeted mutation of the Ets2 transcription factor gene were mated with a mouse strain that develops mammary tumors due to the expression of the polyoma virus middle T oncogene. Tumors from females with only one wild-type Ets2 gene were approximately one-half the size of tumors from controls. The smaller size of the tumors was correlated with a more differentiated state of early hyperplastic growths and not to differential growth of the frank tumors or to decreased middle T gene expression. Ets2 may regulate the progression of these aggressive mammary tumors.

Alleles↗
PubMed1999

Elevated expression of activated forms of Neu/ErbB-2 and ErbB-3 are involved in the induction of mammary tumors in transgenic mice: implications for human breast cancer.

To assess the importance of Neu activation during mammary tumorigenesis, altered receptors harboring in-frame deletions within the extracellular domain were expressed in transgenic mice. Females from several independent lines develop multiple mammary tumors that frequently metastasize to the lung. Tumor progression in these strains was associated with elevated levels of tyrosine-phosphorylated Neu and ErbB-3. Consistent with these observations, a survey of primary human breast tumors revealed frequent co-expression of both erbB-2 and erbB-3 transcripts. The ability of altered Neu receptors to induce mammary tumorigenesis in transgenic mice prompted us to examine whether similar mutations occurred in ErbB-2 during human breast cancer progression. Interestingly, an alternatively spliced form of erbB-2, closely resembling spontaneous activated forms of neu, was detected in human breast tumors. The ErbB-2 receptor encoded by this novel transcript harbors an in-frame deletion of 16 amino acids in the extracellular domain and can transform Rat-1 fibroblasts. Together, these observations argue that co-expression of ErbB-2 and ErbB-3 may play a critical role in the induction of human breast tumors, and raise the possibility that activating mutations in the ErbB-2 receptor may also contribute to this process.

Alleles↗
PubMed1999

Roles for Nkx3.1 in prostate development and cancer.

In aging men, the prostate gland becomes hyperproliferative and displays a propensity toward carcinoma. Although this hyperproliferative process has been proposed to represent an inappropriate reactivation of an embryonic differentiation program, the regulatory genes responsible for normal prostate development and function are largely undefined. Here we show that the murine Nkx3.1 homeobox gene is the earliest known marker of prostate epithelium during embryogenesis and is subsequently expressed at all stages of prostate differentiation in vivo as well as in tissue recombinants. A null mutation for Nkx3.1 obtained by targeted gene disruption results in defects in prostate ductal morphogenesis and secretory protein production. Notably, Nkx3.1 mutant mice display prostatic epithelial hyperplasia and dysplasia that increases in severity with age. This epithelial hyperplasia and dysplasia also occurs in heterozygous mice, indicating haploinsufficiency for this phenotype. Because human NKX3.1 is known to map to a prostate cancer hot spot, we propose that NKX3.1 is a prostate-specific tumor suppressor gene and that loss of a single allele may predispose to prostate carcinogenesis. The Nkx3.1 mutant mice provide a unique animal model for examining the relationship between normal prostate differentiation and early stages of prostate carcinogenesis.

Animals↗
PubMed1999

The comparative pathology of human and mouse mammary glands.

The mouse has emerged as a primary animal model for human breast cancer because the mammary glands of the two species are very similar in structure and function. In this regard the TDLU and LA have similar morphology. The mouse, infected by MMTV, develops "spontaneous" tumors with specific but limited tumor phenotypes. The advent of genetic manipulation has created transgenic mice that develop hyperplasias and tumors morphologically and cytochemically comparable to lesions in humans. Even experienced pathologists have difficulty distinguishing between lesions from the two species, and the morphological similarities support the utility of the mouse model in understanding human breast cancer. In this essay we review our experience with the histopathology of human and mouse mammary disease by comparing the normal gland with hyperplastic, dysplastic and neoplastic lesions of traditional and transgenic origin.

Animals↗
PubMed1999

Accelerated mammary tumor development in mutant polyomavirus middle T transgenic mice expressing elevated levels of either the Shc or Grb2 adapter protein.

The Grb2 and Shc adapter proteins play critical roles in coupling activated growth factor receptors to several cellular signaling pathways. To assess the role of these molecules in mammary epithelial development and tumorigenesis, we have generated transgenic mice which individually express the Grb2 and Shc proteins in the mammary epithelium. Although mammary epithelial cell-specific expression of Grb2 or Shc accelerated ductal morphogenesis, mammary tumors were rarely observed in these strains. To explore the potential role of these adapter proteins in mammary tumorigenesis, mice coexpressing either Shc or Grb2 and a mutant form of polyomavirus middle T (PyV mT) antigen in the mammary epithelium were generated. Coexpression of either Shc or Grb2 with the mutant PyV mT antigen resulted in a dramatic acceleration of mammary tumorigenesis compared to parental mutant PyV mT strain. The increased rate of tumor formation observed in these mice was correlated with activation of the epidermal growth factor receptor family and mitogen-activated protein kinase pathway. These observations suggest that elevated levels of the Grb2 or Shc adapter protein can accelerate mammary tumor progression by sensitizing the mammary epithelial cell to growth factor receptor signaling.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Mammalian Grb2 regulates multiple steps in embryonic development and malignant transformation.

Proteins with SH2 and SH3 domains link tyrosine kinases to intracellular pathways. To investigate the biological functions of a mammalian SH2/SH3 adaptor, we have introduced a null mutation into the mouse gene for Grb2. Analysis of mutant embryonic stem cells, embryos, and chimeras reveals that Grb2 is required during embyrogenesis for the differentiation of endodermal cells and formation of the epiblast. Grb2 acts physiologically as an adaptor, since replacing the C terminus of the Ras activator Sos1 with the Grb2 SH2 domain yields a fusion protein that largely rescues the defects caused by the Grb2 mutation. Furthermore, Grb2 is rate limiting for mammary carcinomas induced by polyomavirus middle T antigen. These data provide genetic evidence for a mammalian Grb2-Ras signaling pathway, mediated by SH2/SH3 domain interactions, that has multiple functions in embryogenesis and cancer.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Active signaling by Neu in transgenic mice.

Transgenic mice engineered to overexpress the HER-2/neu/erbB-2 protooncogene under the control of a mammary-specific promoter develop mammary tumors and are a model for human breast cancer. Signal transduction by Neu was examined in situ in the tumors of these transgenic mice. This was accomplished using the PN2A monoclonal antibody, which recognizes Neu only in the phosphorylated, and therefore actively signaling, state. Immunohistochemistry using PN2A demonstrated that Neu actively signals in the tumors of Neu transgenic mice. Expression of Neu was always accompanied by co-overexpression of the endogenous epidermal growth factor receptor. Qualitatively similar results were found in mammary tumors from mice bitransgenic for the neu and transforming growth factor-alpha genes (both driven by the mouse mammary tumor virus promoter). Early mammary lesions demonstrated distinctive patterns of Neu activation relative to expression levels. Overexpression and activation were separable both temporally and spatially. These results refine the multi-step model for the role of Neu in mammary neoplasia and establish phosphorylation-state specific antibodies as a powerful tool for investigating tumor progression.

Animals↗
PubMed1998

p53 deficiency and misexpression of protein kinase CK2alpha collaborate in the development of thymic lymphomas in mice.

Protein kinase CK2 (casein kinase II) is a serine-threonine protein kinase with many substrates, some of which are involved in cell cycle regulation. CK2 activity is elevated in human solid tumors and leukemia, and dysregulated expression of CK2 induces lymphoma in transgenic mice. Mice that are deficient in p53 also develop lymphomas, and p53 activity may be regulated by CK2 phosphorylation. Here we demonstrate that CK2alpha transgenic mice partially or completely deficient in p53 develop thymic lymphomas at a markedly accelerated rate when compared to p53-deficient mice lacking the transgene. Lymphomas originating from CK2alpha transgenic mice that are heterozygous for p53 generally lose the wild type p53 allele, indicating that loss of p53 is an important step in tumor progression. Moreover, though lymphomas occur as early as 3 weeks of age in the transgenic mice that are nullizygous for p53, they are still monoclonal, indicating that additional stochastic mutations are required for their development. These lymphomas express high levels of myc mRNA and frequently ectopically express Lmo-2, a transcription factor involved in human T cell acute lymphocytic leukemia. The p53-null CK2alpha transgenic lymphomas grow rapidly but are highly prone to apoptosis, suggesting that transformation occurs through synergistic dysregulation of cell cycle control induced by misexpression of CK2 and loss of function of p53.

Animals↗
PubMed1998

The induction of uterine leiomyomas and mammary tumors in transgenic mice expressing polyomavirus (PyV) large T (LT) antigen is associated with the ability of PyV LT antigen to form specific complexes with retinoblastoma and CUTL1 family members.

The inactivation of certain tumor suppressor genes is thought to play an important role in the genesis of a number of tumor types. For example, inactivation of the Retinoblastoma (Rb) tumor suppressor is frequently observed in a proportion of sporadic human breast cancers. While these studies suggest that inactivation of key tumor suppressor genes may play an important role in the induction of mammary cancers, direct evidence supporting this contention is lacking. Because polyomavirus (PyV) Large T (LT) antigen is known to associate with and inactivate certain members of the Rb family (p105Rb, p107, p130), we have derived transgenic mice which express PyV LT antigen in the mammary epithelium. As expected mammary epithelial-specific expression of PyV LT antigen resulted in the induction of mammary tumors which correlated with their capacity to associate with Rb family members. In addition to mammary carcinomas, female transgenic mice expressing the PyV LT transgene frequently develop uterine leiomyomas. Because loss of heterozygosity involving the human CUTL1 (Cut like 1) gene located at chromosomal position 7q22 has been recently implicated in sporadic human uterine leiomyomas, we tested the hypothesis that PyV LT antigen may also form specific complexes with CUTL1. The results of these analyses revealed that specific complexes of CUTL1 and PyV LT antigen could be detected in both leiomyomas and mammary tumors. Taken together, these observations suggest that PyV LT antigen may be involved in inducing these tumors by sequestering both CUTL1 and Rb growth regulatory proteins.

Animals↗
PubMed1998

Word search performance for diagnoses of equine surgical colics in free-text electronic patient records.

The objectives of the current project were to: (1) identify limitations of search sensitivity and positive predictive value (PPV) for free-text surgical diagnoses included in electronic patient records maintained at the University of California, Davis, Veterinary Medical Teaching Hospital (VMTH), (2) develop procedural or programmable recommendations for removing these limitations, and (3) provide guidelines for effective search strategies for users performing aggregate searches using the VMTH clinical information system. Search sensitivity corresponds to detection sensitivity (the capacity of a search term to 'identify' a relevant document) and search PPV indicates the proportion of retrieved documents that are relevant. All horses submitted to the VMTH for a gastrointestinal (GI) disorder requiring surgical intervention in 1995 were identified using procedure codes for billing purposes and stored in the electronic patient record. Patient records and surgical reports were reviewed for causes of GI disorders, and variation in naming of these disorders. Key word searches were performed for four GI disorders, and search performance was evaluated by estimating search sensitivity and PPV. Search sensitivity ranged from 33% to 98%, and PPV ranged from 2% to 74%. The procedural recommendation that would likely have the greatest influence on minimizing these search limitations would be more uniform naming of GI disorders. This would free searchers from having to anticipate all of the exact word combinations that could be used in the relevant documents, and also minimize retrieval of irrelevant documents.

Animals↗
PubMed1998

CD44v(3,8-10) is involved in cytoskeleton-mediated tumor cell migration and matrix metalloproteinase (MMP-9) association in metastatic breast cancer cells.

In the present study, we have employed a unique breast cancer cell line (Met-1, which was derived from a high metastatic potential tumor in transgenic mice expressing polyomavirus middle T oncogene) to study the role of CD44 variant isoform(s) in the regulation of metastatic breast tumor cell behavior. The results of reverse transcriptase-polymerase chain reaction, Southern blot, nucleotide sequencing, immunoprecipitation, and immunoblot analyses indicated that these cells express a major CD44 isoform (molecular weight approximately 260 kDa) containing a v3,8-10 exon insertion (designated as CD44v3,8-10). In addition, we have determined that CD44v3,8-10 binds specifically to the cytoskeletal proteins such as ankyrin. Biochemical analyses, using competition binding assays and a synthetic peptide identical to NGGNGTVEDRKPSEL (a sequence located between aa480 and aa494 of CD44v3,8-10) indicate that this 15-amino acid peptide binds specifically to the cytoskeletal protein ankyrin (but not to fodrin or spectrin). This peptide competes effectively for ankyrin binding to CD44v3,8-10. Therefore, we believe that the sequence 480NGGNGTVEDRKPSE494L, located at the cytoplasmic domain of CD44v3,8-10, is required for the ankyrin binding. We have also detected that CD44v3,8-10-containing Met-1 cells are capable of forming membrane spikes or "invadopodia" structures and undergo active migration processes. Treatments of Met-1 cells with certain agents including anti-CD44v3 antibody, cytochalasin D (a microfilament inhibitor), and W-7 (a calmodulin antagonist), but not colchicine (a microtubule disrupting agent) effectively inhibit "invadopodia" formation and subsequent tumor cell migration. Further analyses using zymography assays and double immunofluorescence staining indicated that CD44v3,8-10 is closely associated with the active form of matrix metalloproteinase, MMP-9, in a complex within "invadopodia" structures. These findings suggest that CD44v3,8-10 plays an important role in linking ankyrin to the membrane-associated actomyosin contractile system required for "invadopodia" formation (coupled with matrix degradation activities) and tumor cell migration during breast cancer progression.

Amino Acid Sequence↗