The Baby Boom Bust: Strategies to Overcome Retirement Brain Drain

[Excerpt] As Corporate America struggles to emerge from the depths of the recession, another crisis awaits them over the horizon with the imminent retirement of the baby boomers. In 2011, this generation’s oldest members turned 65 with approximately 10,000 more expected to join them every day over the next two decades[1]. Current estimates state that 25 million baby boomers will be retiring by 2020, representing 40% of the U.S. workforce. While these figures seem overwhelming, the greatest shock comes from the fact that many companies have not assessed how this will affect their business. In a 2007 study, it was found that 36.7% of employers surveyed had not analyzed retirement projections for their employees and only 9.7% stated they had done so “to a great extent”[2]

The topology of plasminogen binding and activation on the surface of human breast cancer cells

The urokinase-dependent activation of plasminogen by breast cancer cells plays an important role in metastasis. We have previously shown that the metastatic breast cancer cell line MDA-MB-231 over-expresses urokinase and binds and efficiently activates plasminogen at the cell surface compared to non-metastatic cells. The aim of this study was to further characterise plasminogen binding and determine the topology of cell surface-bound plasminogen in terms of its potential for activation. The lysine-dependent binding of plasminogen at 4°C to MDA-MB-231 cells was stable and resulted in an activation-susceptible conformation of plasminogen. Topologically, a fraction of bound plasminogen was co-localised with urokinase on the surfaces of MDA-MB-231 cells where it could be activated to plasmin. At 37°C plasmin was rapidly lost from the cell surface. Apart from actin, other candidate plasminogen receptors were either not expressed or did not co-localise with plasminogen at the cell surface. Thus, based on co-localisation with urokinase, plasminogen binding is partitioned into two functional pools on the surface of MDA-MB-231 cells. In conclusion, these results shed further light on the functional organisation of the plasminogen activation cascade on the surface of a metastatic cancer cell. © 2001 Cancer Research Campaignhttp://www.bjcancer.co

Identification of CM1 as a Pathogenic Factor in Inflammatory Diseases and Cancer

Background: CM1 (centrocyte/-blast marker 1) was defined by a mAb against concavabalin-A (ConA) activated PBMC. It is expressed in germinal center of human tonsil and on the surface of activated PBMC as well as cancer cells. Recently,increased productions of pro-inflammatory mediators were detected from activated PBMC by CM1 ligation. Methods:However, there is a limitation to explain the exact role of CM1 on inflammation and its related mechanisms, since the identity of CM1 is still not clarified. In our previous study, we have already confirmed that soluble form of CM1 was produced by Raji. Therefore, we performed Q-TOF analysis after immunoprecipitation of concentrated Raji culture supernatant using anti-CM1 mAbs. Results: As a result, we found that CM1 is identical to enolase-1(ENO1), a glycolytic enzyme,and we confirmed that results by silencing ENO1 using siRNA. It was also confirmed through competition assay between anti-CM1 and anti-ENO1 mAbs. Finally, we investigated the possible role of CM1 in inflammatory response and cancer. The ligation of CM1 on Raji cells with anti-CM1mAbs induces the extensive production of prostaglandin E2(PGE2). In addition, the increased activity of matrix metalloproteinase (MMP)-2/9 was shown in NCI-N87, stomach cancer cell line by CM1 stimulation. Conlusion: CM1 is identical to ENO1 and it might be an important role in the regulation of inflammatory responses.N

Plasminogen binding and activation at the breast cancer cell surface: the integral role of urokinase activity

INTRODUCTION: The regulation of extracellular proteolytic activity via the plasminogen activation system is complex, involving numerous activators, inhibitors, and receptors. Previous studies on monocytic and colon cell lines suggest that plasmin pre-treatment can increase plasminogen binding, allowing the active enzyme to generate binding sites for its precursor. Other studies have shown the importance of pre-formed receptors such as annexin II heterotetramer. However, few studies have used techniques that exclusively characterise cell-surface events and these mechanisms have not been investigated at the breast cancer cell surface. METHODS: We have studied plasminogen binding to MCF-7 in which urokinase plasminogen activator receptor (uPAR) levels were upregulated by PMA (12-O-tetradecanoylphorbol-13-acetate) stimulation, allowing flexible and transient modulation of cell-surface uPA. Similar experiments were also performed using MDA-MB-231 cells, which overexpress uPAR/uPA endogenously. Using techniques that preserve cell integrity, we characterise the role of uPA as both a plasminogen receptor and activator and quantify the relative contribution of pre-formed and cryptic plasminogen receptors to plasminogen binding. RESULTS: Cell-surface plasminogen binding was significantly enhanced in the presence of elevated levels of uPA in an activity-dependent manner and was greatly attenuated in the presence of the plasmin inhibitor aprotinin. Pre-formed receptors were also found to contribute to increased plasminogen binding after PMA stimulation and to co-localise with uPA/uPAR and plasminogen. Nevertheless, a relatively modest increase in plasminogen-binding capacity coupled with an increase in uPA led to a dramatic increase in the proteolytic capacity of these cells. CONCLUSION: We show that the majority of lysine-dependent plasminogen binding to breast cancer cells is ultimately regulated by plasmin activity and is dependent on the presence of significant levels of active uPA. The existence of a proteolytic positive feedback loop in plasminogen activation has profound implications for the ability of breast cancer cells expressing high amounts of uPA to accumulate a large proteolytic capacity at the cell surface, thereby conferring invasive potential

The Interaction of Canine Plasminogen with Streptococcus pyogenes Enolase: They Bind to One Another but What Is the Nature of the Structures Involved?

For years it has been clear that plasminogen from different sources and enolase from different sources interact strongly. What is less clear is the nature of the structures required for them to interact. This work examines the interaction between canine plasminogen (dPgn) and Streptococcus pyogenes enolase (Str enolase) using analytical ultracentrifugation (AUC), surface plasmon resonance (SPR), fluorescence polarization, dynamic light scattering (DLS), isothermal titration calorimetry (ITC), and simple pull-down reactions. Overall, our data indicate that a non-native structure of the octameric Str enolase (monomers or multimers) is an important determinant of its surface-mediated interaction with host plasminogen. Interestingly, a non-native structure of plasminogen is capable of interacting with native enolase. As far as we can tell, the native structures resist forming stable mixed complexes