180 research outputs found

    Appendices for "Revisiting the Welfare Effects of Eliminating Business Cycles"

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    This paper offers several appendices for the article: the integration principle applied to the baseline model, the computational algorithm for the baseline model, calculating the welfare gain, algorithm for the model with short- and long-term unemployment, as well as additional result tables.

    Tissue transglutaminase-induced alterations in extracellular matrix inhibit tumor invasion

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    BACKGROUND: Alterations in the extracellular matrix (ECM) can affect host-tumor interactions and tumor growth and metastasis. Tissue transglutaminase (TG2, EC 2.3.2.13), a calcium-dependent enzyme that catalyzes covalent cross-linking of proteins, can render the ECM highly stable and resistant to proteolytic degradation. So we determined whether TG2 expression in a tumor or nontumor (stroma) environment could affect the process of metastasis. Two hundred archived samples from patients with breast cancer were studied for the TG2 expression. Also, in an in vitro model the invasive behavior of MDA-MB-231 cells in the presence or absence of exogenous TG2 was determined. RESULTS: Tumors associated with negative nodes showed significantly higher expression of TG2 in the stroma (P < 0.001). TG2 in the stroma was catalytically active, as revealed by the presence of isopeptide cross-links. Pretreatment of Matrigel with catalytically active TG2 resulted in strong inhibition of invasion of MDA-MB-231 cells through the Matrigel Transwell filters. CONCLUSION: TG2-induced alterations in the ECM could effectively inhibit the process of metastasis. Therefore, selective induction of catalytically active TG2 at the site of tumor may offer promising approach for limiting the metastasis

    Enterobiasis of the Ovary in a Patient With Cervical Carcinoma In Situ

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    Background: Enterobiasis occurs throughout the female genital tract and may involve peritoneal surfaces. It is generally an incidental finding at surgery or at autopsy but occasionally is symptomatic. Most of the superficial lesions are composed of granulomas with variable fibrosis in which diagnostic eggs are found, often associated with degenerated adult worms. Multiple histologic sections may be required to establish the diagnosis in older lesions

    Heregulin and HER2 signaling selectively activates c-Src phosphorylation at tyrosine 215

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    AbstractTo elucidate the molecular mechanisms by which human epidermal growth factor receptor/heregulin (HER2/HRG) influence the migratory potential of breast cancer cells, we have used phospho-specific antibodies against c-Src kinase and focal adhesion kinase (FAK). This study establishes that HER2/HRG signaling selectively upregulates Tyr phosphorylation of c-Src at Tyr-215 located within the SH2 domain, increases c-Src kinase activity and selectively upregulates Tyr phosphorylation of FAK at Tyr-861. HER2-overexpressing tumors showed increased levels of c-Src phosphorylation at Tyr-215. These findings suggest that HER2/HRG influence metastasis of breast cancer cells through a novel signaling pathway involving phosphorylation of FAK tyrosine 861 via activation of c-Src tyrosine 215

    Gene expression signature of estrogen receptor α status in breast cancer

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    BACKGROUND: Estrogens are known to regulate the proliferation of breast cancer cells and to modify their phenotypic properties. Identification of estrogen-regulated genes in human breast tumors is an essential step toward understanding the molecular mechanisms of estrogen action in cancer. To this end we generated and compared the Serial Analysis of Gene Expression (SAGE) profiles of 26 human breast carcinomas based on their estrogen receptor α (ER) status. Thus, producing a breast cancer SAGE database of almost 2.5 million tags, representing over 50,000 transcripts. RESULTS: We identified 520 transcripts differentially expressed between ERα-positive (+) and ERα-negative (-) primary breast tumors (Fold change ≥ 2; p < 0.05). Furthermore, we identified 220 high-affinity Estrogen Responsive Elements (EREs) distributed on the promoter regions of 163 out of the 473 up-modulated genes in ERα (+) breast tumors. In brief, we observed predominantly up-regulation of cell growth related genes, DNA binding and transcription factor activity related genes based on Gene Ontology (GO) biological functional annotation. GO terms over-representation analysis showed a statistically significant enrichment of various transcript families including: metal ion binding related transcripts (p = 0.011), calcium ion binding related transcripts (p = 0.033) and steroid hormone receptor activity related transcripts (p = 0.031). SAGE data associated with ERα status was compared with reported information from breast cancer DNA microarrays studies. A significant proportion of ERα associated gene expression changes was validated by this cross-platform comparison. However, our SAGE study also identified novel sets of genes as highly expressed in ERα (+) invasive breast tumors not previously reported. These observations were further validated in an independent set of human breast tumors by means of real time RT-PCR. CONCLUSION: The integration of the breast cancer comparative transcriptome analysis based on ERα status coupled to the genome-wide identification of high-affinity EREs and GO over-representation analysis, provide useful information for validation and discovery of signaling networks related to estrogen response in this malignancy

    MTA1 Interacts with MAT1, a cyclin-dependent kinase-activating kinase complex ring finger factor and regulates estrogen receptor transactivation functions

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    The transcriptional activity of estrogen receptor-&#945; is controlled by coregulators. MTA1 (metastasis-associated protein1) represses estrogen receptor-&#945;-driven transcription by recruiting Histone Deacetylases (HDACs) to the estrogen response element containing target gene chromatin in breast cancer cells. Using a yeast two-hybrid screen with the MTA1 C-terminal domain as bait, we identified MAT1 (menage a trois 1) as an MTA1-binding protein. MAT1 is an assembly/targeting factor for cyclin-dependent kinase-activating kinase (CAK), which has been shown to functionally interact with general transcriptional factor TFIIH, a known inducer of ER transactivation. We show that estrogen signaling promotes nuclear translocation of MAT1 and that MTA1 interacts with MAT1 both in vitro and in vivo. MAT1 binds to the C-terminal 389–441 amino acids GATA domain and N-terminal 1–164 amino acids bromo-domain of MTA1, whereas MTA1 binds to the N-terminal ring finger domain of the MAT1. In addition, MAT1 interacts with the activation function 2 domain of ER and colocalizes with ER in activated cells. MTA1 deregulation in breast cancer cells led to its interactions with the CAK complex components, ER and HDAC2. Accordingly, MTA1 inhibited CAK stimulation of ER transactivation that was partially relieved by HDAC inhibitor trichostatin A, suggesting that MTA1 might inhibit CAK-induced transactivation function of ER by recruiting HDAC. Furthermore, MTA1 overexpression inhibited the ability of CAK complex to phosphorylate ER. Together, these findings identified MAT1 as a target of MTA1 and provided new evidence to suggest that the transactivation functions of ER might be influenced by the regulatory interactions between CAK and MTA1 in breast cancer cells

    Tumor Suppressor DEAR1 Regulates Mammary Epithelial Cell Fate and Predicts Early Onset and Metastasis in Triple Negative Breast Cancer

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    Triple negative breast cancer (TNBC) is a disease of poor prognosis, with the majority classified as the basal-like subtype associated with epithelial-mesenchymal transition and metastasis. Because basal breast cancers originate from proliferative luminal progenitor-like cells upon dysregulation of proper luminal differentiation, genes regulating luminal-basal transition are critical to elucidate novel therapeutic targets to improve TNBC outcomes. Herein we demonstrate that the tumor suppressor DEAR1/TRIM62 is a critical regulator of luminal cell fate. DEAR1 loss in human mammary epithelial cells results in significantly enhanced mammosphere formation that is accelerated in the presence of TGF-β/SMAD3 signaling. Mammospheres formed following DEAR1 loss are enriched for ALDH1A1 and CK5 expression, EpCAM-/CD49f+ and CD44high/24low basal-like epithelial cells, indicating that DEAR1 regulates stem/progenitor cell properties and luminal-basal progenitor transition. We show that DEAR1 maintains luminal differentiation as a novel ubiquitin ligase for SNAI2/SLUG, a master regulator driving stemness and generation of basal-like progenitor populations. We also identify a significant inverse correlation between DEAR1 and SNAI2 expression in a 103 TNBC case cohort and show that low DEAR1 expression significantly correlates with young age of onset and shorter time to metastasis, suggesting DEAR1 could serve as a biomarker to stratify early onset TNBCs for targeted stem cell therapies

    PI3K Pathway Mutations and PTEN Levels in Primary and Metastatic Breast Cancer

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    The purpose of this work was to determine whether there are differences in PIK3CA mutation status and PTEN protein expression between primary and matched metastatic breast tumors as this could influence patient management. Fifty-micron paraffin sections were used for DNA extraction and 3-micron slides for immunohistochemistry (IHC) and fluorescent in-situ hybridization (FISH). ER, PR and HER2 IHC were repeated in a central laboratory for both primary and metastasis. PTEN levels were assessed by IHC and PI3K pathway mutations detected by a mass spectroscopy-based approach. Median age was 48 years (range, 30 to 83 years). Tumor subtype included 72% hormone receptor-positive/HER2-negative, 20% HER2-positive, and less than 7.8% triple receptor negative. Tissues were available for PTEN IHC in 46 primary tumors and 52 metastases. PTEN was lost in 14 (30%) primary tumors and 13 (25%) metastases. There were 5 cases of PTEN loss and eight cases of PTEN gain from primary to metastasis (26% discordance). Adequate DNA was obtained on 46 primary tumors and on 50 metastases for PIK3CA analysis. PIK3CA mutations were detected in 19 (40%) of primary tumors and 21 (42%) of metastases. There were five cases of PIK3CA mutation loss, and four cases of mutation gain (18% discordance). There was an increase of the level of PIK3CA mutations in four cases, and decrease in one from primary to metastasis. There is a high level of discordance in PTEN level, PIK3CA mutations, and receptor status between primary and metastatic disease that may influence patient selection and response to PI3K-targeted therapies
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