Life Sciences Commons^™

Age And Sex Differences And 20-Year Trends (1986 To 2005) In Prehospital Delay In Patients Hospitalized With Acute Myocardial Infarction, Hoa Nguyen, Joel Gore, Jane Saczynski, Jorge Yarzebski, George Reed, Frederick Spencer, Robert Goldberg

Jorge L. Yarzebski

Background: The prompt administration of coronary reperfusion therapy for patients with an evolving acute myocardial infarction (AMI) is crucial in reducing mortality and the risk of serious clinical complications in these patients. However, long-term trends in extent of prehospital delay and factors affecting patient's care-seeking behavior remain relatively unexplored, especially in men and women of different ages. The objectives of this study were to examine the overall magnitude and 20-year trends (1986 to 2005) in duration of prehospital delay in middle-aged and elderly men and women hospitalized with AMI.

Methods and Results: The study sample consisted of 5967 residents of …

Integrin (Alpha 6 Beta 4) Regulation Of Eif-4e Activity And Vegf Translation: A Survival Mechanism For Carcinoma Cells, Jun Chung, Robin E. Bachelder, Elizabeth A. Lipscomb, Leslie M. Shaw, Arthur M. Mercurio

Arthur M. Mercurio

We define a novel mechanism by which integrins regulate growth factor expression and the survival of carcinoma cells. Specifically, we demonstrate that the alpha 6 beta 4 integrin enhances vascular endothelial growth factor (VEGF) translation in breast carcinoma cells. The mechanism involves the ability of this integrin to stimulate the phosphorylation and inactivation of 4E-binding protein (4E-BP1), a translational repressor that inhibits the function of eukaryotic translation initiation factor 4E (eIF-4E). The regulation of 4E-BP1 phosphorylation by alpha 6 beta 4 derives from the ability of this integrin to activate the PI-3K-Akt pathway and, consequently, the rapamycin-sensitive kinase mTOR that …

Evidence That Distinct States Of The Integrin Alpha6beta1 Interact With Laminin And An Adam, M. S. Chen, E. A. Almeida, A. P. Huovila, Y. Takahashi, Leslie M. Shaw, Arthur M. Mercurio, J. M. White

Arthur M. Mercurio

Integrins can exist in different functional states with low or high binding capacity for particular ligands. We previously provided evidence that the integrin alpha6beta1, on mouse eggs and on alpha6-transfected cells, interacted with the disintegrin domain of the sperm surface protein ADAM 2 (fertilin beta). In the present study we tested the hypothesis that different states of alpha6beta1 interact with fertilin and laminin, an extracellular matrix ligand for alpha6beta1. Using alpha6-transfected cells we found that treatments (e.g., with phorbol myristate acetate or MnCl2) that increased adhesion to laminin inhibited sperm binding. Conversely, treatments that inhibited laminin adhesion increased sperm binding. …

The Integrin Alpha6beta4 Functions In Carcinoma Cell Migration On Laminin-1 By Mediating The Formation And Stabilization Of Actin-Containing Motility Structures, Isaac Rabinovitz, Arthur M. Mercurio

Arthur M. Mercurio

Functional studies on the alpha6beta4 integrin have focused primarily on its role in the organization of hemidesmosomes, stable adhesive structures that associate with the intermediate filament cytoskeleton. In this study, we examined the function of the alpha6beta4 integrin in clone A cells, a colon carcinoma cell line that expresses alpha6beta4 but no alpha6beta1 integrin and exhibits dynamic adhesion and motility on laminin-1. Time-lapse videomicroscopy of clone A cells on laminin-1 revealed that their migration is characterized by filopodial extension and stabilization followed by lamellae that extend in the direction of stabilized filopodia. A function-blocking mAb specific for the alpha6beta4 integrin …

Integrin Alpha 6 Beta 4 Mediates Dynamic Interactions With Laminin, Aydin Tozeren, Hynda K. Kleinman, Stephen Wu, Arthur M. Mercurio, Stephen W. Byers

Arthur M. Mercurio

We present here a novel form of dynamic adhesion in which both the integrin receptor and the ligand supporting dynamic adhesion have been identified. Laminar flow assays showed that laminin supported attachment of alpha 6 beta 4-positive cells in the presence of fluid shear stress (tau < or = 2 dyn/cm2), indicating that these cells adhered to laminin within a fraction of a second. Further increases in flow rate (3.5 dyn/cm2 < or = tau < or = 100 dyn/cm2) initiated rolling of attached cells in the direction of flow, suggesting that rapidly formed adhesion is reversible and repeatable. Laminin fragment E8, which …

Role Of E-Cadherin In The Response Of Tumor Cell Aggregates To Lymphatic, Venous And Arterial Flow: Measurement Of Cell-Cell Adhesion Strength, Stephen W. Byers, Connie L. Sommers, Becky Hoxter, Arthur M. Mercurio, Aydin Tozeren

Arthur M. Mercurio

Defects in the expression or function of the calcium dependent cell-cell adhesion molecule E-cadherin are common in invasive, metastatic carcinomas. In the present study the response of aggregates of breast epithelial cells and breast and colon carcinoma cells to forces imposed by laminar flow in a parallel plate flow channel was examined. Although E-cadherin negative tumor cells formed cell aggregates in the presence of calcium, these were significantly more likely than E-cadherin positive cell aggregates to disaggregate in response to low shear forces, such as those found in a lymphatic vessel or venule (< 3.5 dyn/cm2). E-cadherin positive normal breast epithelial cells and E-cadherin positive breast tumor cell aggregates could not be disaggregated when exposed to shear forces in excess of those found in arteries (> 100 dyn/cm2). E-cadherin negative cancer cells …

Human Colon Carcinoma Cells Use Multiple Receptors To Adhere To Laminin: Involvement Of Alpha 6 Beta 4 And Alpha 2 Beta 1 Integrins, Margaret M. Lotz, Cynthia A. Korzelius, Arthur M. Mercurio

Arthur M. Mercurio

In this study, we used clone A, a human colon carcinoma cell line, to characterize those integrins that mediate colon carcinoma adhesion to laminin. Monoclonal antibodies specific for the human beta 1 subunit inhibited clone A adhesion to laminin. They also precipitated a complex of surface proteins that exhibited an electrophoretic behavior characteristic of alpha 2 beta 1 and alpha 3 beta 1. A monoclonal antibody specific for alpha 2 (PIH5) blocked clone A adhesion to laminin, as well as to collagen I. An alpha 3-specific antibody (P1B5) had no effect on clone A adhesion to laminin, even though it …

Regulation Of Cellular Interactions With Laminin By Integrin Cytoplasmic Domains: The A And B Structural Variants Of The Alpha 6 Beta 1 Integrin Differentially Modulate The Adhesive Strength, Morphology, And Migration Of Macrophages, Leslie M. Shaw, Arthur M. Mercurio

Arthur M. Mercurio

Several integrin alpha subunits have structural variants that are identical in their extracellular and transmembrane domains but that differ in their cytoplasmic domains. The functional significance of these variants, however, is unknown. In the present study, we examined the possibility that the A and B variants of the alpha 6 beta 1 integrin laminin receptor differ in function. For this purpose, we expressed the alpha 6A and alpha 6B cDNAs, as well as a truncated alpha 6 cDNA (alpha 6-delta CYT) in which the cytoplasmic domain sequence was deleted after the GFFKR pentapeptide, in P388D1 cells, an alpha 6 deficient …

Adam12 Induces Actin Cytoskeleton And Extracellular Matrix Reorganization During Early Adipocyte Differentiation By Regulating Beta1 Integrin Function, Nobuko Kawaguchi, Christina Sundberg, Marie Kveiborg, Behzad Moghadaszadeh, Meena Asmar, Nikolaj Dietrich, Charles Kumar Thodeti, Finn C. Nielsen, Peter Moller, Arthur M. Mercurio, Reidar Albrechtsen, Ulla M. Wewer

Arthur M. Mercurio

Changes in cell shape are a morphological hallmark of differentiation. In this study we report that the expression of ADAM12, a disintegrin and metalloprotease, dramatically affects cell morphology in preadipocytes, changing them from a flattened, fibroblastic appearance to a more rounded shape. We showed that the highest levels of ADAM12 mRNA were detected in preadipocytes at the critical stage when preadipocytes become permissive for adipogenic differentiation. Furthermore, as assessed by immunostaining, ADAM12 was transiently expressed at the cell surface concomitant with the reduced activity of beta1 integrin. Co-immunoprecipitation studies indicated the formation of ADAM12/beta1 integrin complexes in these preadipocytes. Overexpression …

Endothelial Cells Assemble Two Distinct Alpha6beta4-Containing Vimentin-Associated Structures: Roles For Ligand Binding And The Beta4 Cytoplasmic Tail, Suzanne M. Homan, Arthur M. Mercurio, Susan E. Laflamme

Arthur M. Mercurio

The alpha6beta4 laminin binding integrin functions in the assembly of type I hemidesmosomes, which are specialized cell-matrix adhesion sites found in stratified epithelial cells. Although endothelial cells do not express all the components of type I hemidesmosomes, endothelial cells can express the alpha6beta4 integrin. Because endothelial cells lose expression of alpha6beta4 in culture, we expressed recombinant alpha6beta4 in the dermal microvascular endothelial cell line, HMEC-1, to test whether endothelial cells can assemble adhesion structures containing alpha6beta4. Using immunofluorescence microscopy, we found that recombinant alpha6beta4 concentrates specifically in a novel fibrillar structure on the basal surface of endothelial cells in the …

Regulation Of Alpha 6 Beta 1 Integrin Laminin Receptor Function By The Cytoplasmic Domain Of The Alpha 6 Subunit, Leslie M. Shaw, Arthur M. Mercurio

Arthur M. Mercurio

The alpha 6 beta 1 integrin is expressed on the macrophage surface in an inactive state and requires cellular activation with PMA or cytokines to function as a laminin receptor (Shaw, L. M., J. M. Messier, and A. M. Mercurio. 1990. J. Cell Biol. 110:2167-2174). In the present study, the role of the alpha 6 subunit cytoplasmic domain in alpha 6 beta 1 integrin activation was examined. The use of P388D1 cells, an alpha 6-integrin deficient macrophage cell line, facilitated this analysis because expression of either the alpha 6A or alpha 6B subunit cDNAs restores their activation responsive laminin adhesion …

Transcriptional Activation Of Integrin Beta6 During The Epithelial-Mesenchymal Transition Defines A Novel Prognostic Indicator Of Aggressive Colon Carcinoma, Richard C. Bates, David I. Bellovin, Courtney Brown, Elizabeth Maynard, Bingyan Wu, Hisaaki Kawakatsu, Dean Sheppard, Peter Oettgen, Arthur M. Mercurio

Arthur M. Mercurio

We used a spheroid model of colon carcinoma to analyze integrin dynamics as a function of the epithelial-mesenchymal transition (EMT), a process that provides a paradigm for understanding how carcinoma cells acquire a more aggressive phenotype. This EMT involves transcriptional activation of the beta6 integrin subunit and a consequent induction of alphavbeta6 expression. This integrin enhances the tumorigenic properties of colon carcinoma, including activation of autocrine TGF-beta and migration on interstitial fibronectin. Importantly, this study validates the clinical relevance of the EMT. Kaplan-Meier analysis of beta6 expression in 488 colorectal carcinomas revealed a striking reduction in median survival time of …

The Activation Dependent Adhesion Of Macrophages To Laminin Involves Cytoskeletal Anchoring And Phosphorylation Of The Alpha 6 Beta 1 Integrin, Leslie M. Shaw, Jeanne M. Messier, Arthur M. Mercurio

Arthur M. Mercurio

Macrophages require activation with either PMA (Mercurio, A. M., and L. M. Shaw. 1988. J. Cell Biol. 107:1873-1880) or interferon-gamma (Shaw, L. M., and A. M. Mercurio. 1989. J. Exp. Med. 169:303-308) to adhere to a laminin substratum. In the present study, we identified an integrin laminin receptor on macrophages and characterized cellular changes that occur in response to PMA activation that facilitate laminin adhesion. A monoclonal antibody (GoH3) that recognizes the integrin alpha 6 subunit (Sonnenberg, A., H. Janssen, F. Hogervorst, J. Calafat, and J. Hilgers. 1987. J. Biol. Chem. 262:10376-10383) specifically inhibited adhesion to laminin-coated surfaces. This antibody …

P53 Inhibits Alpha 6 Beta 4 Integrin Survival Signaling By Promoting The Caspase 3-Dependent Cleavage Of Akt/Pkb, Robin E. Bachelder, Mark J. Ribick, Alessandra Marchetti, Rita Falcioni, Silvia Soddu, Kathryn R. Davis, Arthur M. Mercurio

Arthur M. Mercurio

Although the interaction of matrix proteins with integrins is known to initiate signaling pathways that are essential for cell survival, a role for tumor suppressors in the regulation of these pathways has not been established. We demonstrate here that p53 can inhibit the survival function of integrins by inducing the caspase-dependent cleavage and inactivation of the serine/threonine kinase AKT/PKB. Specifically, we show that the alpha6beta4 integrin promotes the survival of p53-deficient carcinoma cells by activating AKT/PKB. In contrast, this integrin does not activate AKT/PKB in carcinoma cells that express wild-type p53 and it actually stimulates their apoptosis, in agreement with …

The Integrin Alpha 6 Beta 4 Is A Laminin Receptor, Edward C. Lee, Margaret M. Lotz, Glenn D. Steele Jr., Arthur M. Mercurio

Arthur M. Mercurio

In this study, the putative laminin receptor function of the alpha 6 beta 4 integrin was assessed. For this purpose, we used a human cell line, referred to as clone A, that was derived from a highly invasive, colon adenocarcinoma. This cell line, which expresses the alpha 6 beta 4 integrin, adheres to the E8 and not to the P1 fragment of laminin. The adhesion of clone A cells to laminin is extremely rapid with half-maximal adhesion observed at 5 min after plating. Adhesion to laminin is blocked by GoH3, and alpha 6 specific antibody (60% inhibition), as well as …

Glycogen Synthase Kinase-3 Is An Endogenous Inhibitor Of Snail Transcription: Implications For The Epithelial-Mesenchymal Transition, Robin E. Bachelder, Sang-Oh Yoon, Clara Franci, Antonio Garcia De Herreros, Arthur M. Mercurio

Arthur M. Mercurio

We report that the activity of glycogen synthase kinase-3 (GSK-3) is necessary for the maintenance of the epithelial architecture. Pharmacological inhibition of its activity or reducing its expression using small interfering RNAs in normal breast and skin epithelial cells results in a reduction of E-cadherin expression and a more mesenchymal morphology, both of which are features associated with an epithelial-mesenchymal transition (EMT). Importantly, GSK-3 inhibition also stimulates the transcription of Snail, a repressor of E-cadherin and an inducer of the EMT. We identify NFkappaB as a transcription factor inhibited by GSK-3 in epithelial cells that is relevant for Snail expression. …

Release Of Camp Gating By The Alpha6beta4 Integrin Stimulates Lamellae Formation And The Chemotactic Migration Of Invasive Carcinoma Cells, Kathleen L. O'Connor, Leslie M. Shaw, Arthur M. Mercurio

Arthur M. Mercurio

The alpha6beta4 integrin promotes carcinoma in-vasion by its activation of a phosphoinositide 3-OH (PI3-K) signaling pathway (Shaw, L.M., I. Rabinovitz, H.H.-F. Wang, A. Toker, and A.M. Mercurio. Cell. 91: 949-960). We demonstrate here using MDA-MB-435 breast carcinoma cells that alpha6beta4 stimulates chemotactic migration, a key component of invasion, but that it has no influence on haptotaxis. Stimulation of chemotaxis by alpha6beta4 expression was observed in response to either lysophosphatidic acid (LPA) or fibroblast conditioned medium. Moreover, the LPA-dependent formation of lamellae in these cells is dependent upon alpha6beta4 expression. Both lamellae formation and chemotactic migration are inhibited or "gated" by …

Protein Kinase C-Dependent Mobilization Of The Alpha6beta4 Integrin From Hemidesmosomes And Its Association With Actin-Rich Cell Protrusions Drive The Chemotactic Migration Of Carcinoma Cells, Isaac Rabinovitz, Alex Toker, Arthur M. Mercurio

Arthur M. Mercurio

We explored the hypothesis that the chemotactic migration of carcinoma cells that assemble hemidesmosomes involves the activation of a signaling pathway that releases the alpha6beta4 integrin from these stable adhesion complexes and promotes its association with F-actin in cell protrusions enabling it to function in migration. Squamous carcinoma-derived A431 cells were used because they express alpha6beta4 and migrate in response to EGF stimulation. Using function-blocking antibodies, we show that the alpha6beta4 integrin participates in EGF-stimulated chemotaxis and is required for lamellae formation on laminin-1. At concentrations of EGF that stimulate A431 chemotaxis ( approximately 1 ng/ml), the alpha6beta4 integrin is …

Body Mass Index, Treatment Practices, And Mortality In Patients With Acute Heart Failure, Timothy Fitzgibbons, Olga Hardy, Darleen Lessard, Joel Gore, Jorge Yarzebski, Robert Goldberg

Jorge L. Yarzebski

OBJECTIVES: Obesity is associated with an increased risk of heart failure (HF). Among patients presenting with acute HF, however, differences in clinical characteristics, treatment regimens, and short-term prognosis of varying weights are largely unknown, particularly from a broader population-based perspective. METHODS: A total of 3722 patients admitted with acute HF to 11 greater Worcester (Massachusetts, USA) hospitals during 1995 and 2000 were categorized as being lean (n = 216), normal weight (n = 1465), overweight (n = 1007), or obese (n = 1034) at the time of hospitalization. RESULTS: Obese patients with decompensated HF were significantly younger (mean age = …

Multidecade-Long Trends (1986-2005) In The Utilization Of Coronary Reperfusion And Revascularization Treatment Strategies In Patients Hospitalized With Acute Myocardial Infarction: A Community-Wide Perspective, Jared Wasser, Robert Goldberg, Frederick Spencer, Jorge Yarzebski, Joel Gore

Jorge L. Yarzebski

OBJECTIVES: The objectives of our community-wide investigation were to describe multidecade-long trends (1986-2005) in the utilization of thrombolytic therapy, percutaneous coronary interventions, and coronary artery bypass graft surgery in patients hospitalized with acute myocardial infarction (AMI). METHODS: The study sample consisted of 9422 greater Worcester (MA) residents hospitalized with confirmed AMI at all metropolitan Worcester medical centers in 11 annual periods between 1986 and 2005. RESULTS: Increases in the utilization of percutaneous coronary interventions were observed between 1986 (2.0%) and 2005 (50.7%) with the most rapid increases beginning in the late 1990s. Utilization of coronary artery bypass graft surgery during …

Long-Term Trends In The Use Of Coronary Reperfusion Strategies In Acute Myocardial Infarction: A Community-Wide Perspective, Robert Goldberg, Frederick Spencer, Joseph Okolo, Darleen Lessard, Jorge Yarzebski, Joel Gore

Jorge L. Yarzebski

BACKGROUND: The objectives of our study were to examine long-term (1986-2003) trends in the use of percutaneous coronary interventions (PCI) and thrombolytic therapy in the management of patients hospitalized with acute myocardial infarction (AMI) while our secondary study goal was to examine factors associated with use of these coronary reperfusion strategies. While there have been considerable changes in the management of patients hospitalized with AMI over time, limited contemporary data are available about changing trends in the use of different coronary reperfusion strategies, particularly from the more generalizable perspective of a population-based investigation. METHODS: The study sample consisted of 9,422 …

Use Of Do-Not-Resuscitate Orders In Patients With Kidney Disease Hospitalized With Acute Myocardial Infarction, Joline Chen, Jonathan Sosnov, Darleen Lessard, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: Patients with kidney disease are at increased risk for adverse health outcomes in comparison to patients without kidney disease. Therefore, patients with kidney disease may have greater use of do-not-resuscitate (DNR) orders than patients without kidney disease in the setting of an acute illness. We examined the association between advanced kidney disease and use of DNR orders in patients admitted with an acute myocardial infarction (AMI) to all greater Worcester, MA, hospitals as part of an epidemiological study.

METHODS: Use of DNR orders in 4,033 Worcester residents hospitalized with AMI at 11 greater Worcester medical centers during 1997, 1999, …

Treatment Practices And Outcomes Of Patients With Established Peripheral Arterial Disease Hospitalized With Acute Myocardial Infarction In A Community Setting, Frederick Spencer, Darleen Lessard, Chyke Doubeni, Jorge Yarzebski, Joel Gore, Robert Goldberg

Jorge L. Yarzebski

BACKGROUND: There are little contemporary data available describing the hospital and long-term outcomes of patients with peripheral arterial disease (PAD) who are hospitalized with acute myocardial infarction (AMI). The objectives of our population-based study were to examine the hospital and long-term outcomes, as well as the use of different treatment practices, among patients with established PAD who were hospitalized with AMI. METHODS: The study sample consisted of 4480 patients hospitalized with AMI at all Worcester, Mass, medical centers in 4 alternate years between 1997 and 2003. RESULTS: Among the metropolitan Worcester residents hospitalized with AMI, 13.5% had a history of …

Communities Of Cloacal Bacteria In Tree Swallow Families, Michael Lombardo, Patrick Thorpe, R. Cichewicz, M. Henshaw, C. Millard, C. Steen, T. Zeller

Michael P Lombardo

Our aim in this study was to survey the communities of bacteria found in the cloacae of adult and nestling Tree Swallows (Tachycineta bicolor), determine if there were familial patterns of prevalence, and determine if there were relationships between bacteria loads and nestling size when 12 days old and fledging success.

Pharmacology Supplement, Ahmed Mustafa, Ellioott Blumenthal

Ahmed Mustafa Dr.

No abstract provided.