Sphingosine 1-Phosphate Receptor 5 (S1P5) Deficiency Promotes Proliferation and Immortalization of Mouse Embryonic Fibroblasts.

Sphingosine 1-phosphate (S1P), a bioactive lipid, interacts with five widely expressed G protein-coupled receptors (S1P1-5), regulating a variety of downstream signaling pathways with overlapping but also opposing functions. To date, data regarding the role of S1P5 in cell proliferation are ambiguous, and its role in controlling the growth of untransformed cells remains to be fully elucidated. In this study, we examined the effects of S1P5 deficiency on mouse embryonic fibroblasts (MEFs).

Malnutrition in Hospitalised Children-An Evaluation of the Efficacy of Two Nutritional Screening Tools.

Nutritional risk screening (NRS) is not yet established in many clinical settings. This study aimed to evaluate the efficacy of two NRS tools; the Paediatric Yorkhill Malnutrition Score (PYMS) and the Screening Tool for the Assessment of Malnutrition in Paediatrics (STAMP), compared to the global dietitians' clinical judgment. The goal of this study was also to estimate the prevalence of nutritional risk in Greek paediatric patients.

[Multiple sclerosis and immuno-modulators of sphingosine 1-phosphate receptors].

Multiple sclerosis (MS) is a disease of the central nervous system with a very debilitating inflammatory component that usually affects young people (years 20-40). This disease is characterized by the progressive destruction of the myelin sheath of the axons by the cells of the immune system, which results in neuronal degeneration. The T and B lymphocytes are the main players in this disease, which can be remittent with relapses or progressive.

Development and characterization of sphingosine 1-phosphate receptor 1 monoclonal antibody suitable for cell imaging and biochemical studies of endogenous receptors.

Although sphingosine-1-phosphate receptor 1 (S1P1) has been shown to trigger several S1P targeted functions such as immune cell trafficking, cell proliferation, migration, or angiogenesis, tools that allow the accurate detection of endogenous S1P1 localization and trafficking remain to be obtained and validated. In this study, we developed and characterized a novel monoclonal S1P1 antibody. Mice were immunized with S1P1 produced in the yeast Pichia pastoris and nine hybridoma clones producing monoclonal antibodies were created.

p27 regulates the microtubule bundling activity of PRC1.

Cytokinesis begins in anaphase with the formation of the central spindle. PRC1 is a microtubule associated protein that plays an essential role in central spindle formation by crosslinking antiparallel microtubules. We have identified PRC1 as a novel binding partner for p27 (p27).

Sphingosine 1-phosphate signaling through its receptor S1P promotes chromosome segregation and mitotic progression.

Sphingosine kinase 1 (SphK1) promotes cell proliferation and survival, and its abundance is often increased in tumors. SphK1 produces the signaling lipid sphingosine 1-phosphate (S1P), which activates signaling cascades downstream five G protein-coupled receptors (S1P) to modulate vascular and immune system function and promote proliferation. We identified a new function of the SphK1-S1P pathway specifically in the control of mitosis.

Gem GTPase acts upstream Gmip/RhoA to regulate cortical actin remodeling and spindle positioning during early mitosis.

Gem is a small guanosine triphosphate (GTP)-binding protein within the Ras superfamily, involved in the regulation of voltage-gated calcium channel activity and cytoskeleton reorganization. Gem overexpression leads to stress fiber disruption, actin and cell shape remodeling and neurite elongation in interphase cells. In this study, we show that Gem plays a crucial role in the regulation of cortical actin cytoskeleton that undergoes active remodeling during mitosis.

The GTPase Gem and its partner Kif9 are required for chromosome alignment, spindle length control, and mitotic progression.

Within the Ras superfamily, Gem is a small GTP-binding protein that plays a role in regulating Ca(2+) channels and cytoskeletal remodeling in interphase cells. Here, we report for the first time that Gem is a spindle-associated protein and is required for proper mitotic progression. Functionally, loss of Gem leads to misaligned chromosomes and prometaphase delay.

RalA and RalB proteins are ubiquitinated GTPases, and ubiquitinated RalA increases lipid raft exposure at the plasma membrane.

Ras GTPases signal by orchestrating a balance among several effector pathways, of which those driven by the GTPases RalA and RalB are essential to Ras oncogenic functions. RalA and RalB share the same effectors but support different aspects of oncogenesis. One example is the importance of active RalA in anchorage-independent growth and membrane raft trafficking.

SH3BP1, an exocyst-associated RhoGAP, inactivates Rac1 at the front to drive cell motility.

The coordination of the several pathways involved in cell motility is poorly understood. Here, we identify SH3BP1, belonging to the RhoGAP family, as a partner of the exocyst complex and establish a physical and functional link between two motility-driving pathways, the Ral/exocyst and Rac signaling pathways. We show that SH3BP1 localizes together with the exocyst to the leading edge of motile cells and that SH3BP1 regulates cell migration via its GAP activity upon Rac1.

The membrane-tubulating potential of amphiphysin 2/BIN1 is dependent on the microtubule-binding cytoplasmic linker protein 170 (CLIP-170).

Amphiphysins are BIN-amphiphysin-RVS (BAR) domain-containing proteins that influence membrane curvature in sites such as T-tubules in muscular cells, endocytic pits in neuronal as well as non-neuronal cells, and possibly cytoplasmic endosomes. This effect on lipid membranes is fulfilled by diverse amphiphysin 2/BIN1 isoforms, generated by alternative splicing and showing distinct structural and functional properties. In this study, our goal was to characterize the functional role of a ubiquitously expressed amphiphysin 2/BIN1 by the characterization of new molecular partners.

Opioids modulate constitutive B-lymphocyte secretion.

The opioid system plays a major role in immunomodulation, while its action on cells of the immune system may be opioid receptor-mediated or not. Opioid effects on B-lymphocytes are considered as indirect, attributed to an interplay between distinct cell populations. The aim of the present study was to investigate whether opioid agonists (morphine, alpha(S1)-casomorphin and ethylketocyclazocine) may have a direct action on the secretion of antibodies and cytokines by multiple myeloma-derived cell lines and normal CD19+ B-lymphocytes.

Gem associates with Ezrin and acts via the Rho-GAP protein Gmip to down-regulate the Rho pathway.

Gem is a protein of the Ras superfamily that plays a role in regulating voltage-gated Ca2+ channels and cytoskeletal reorganization. We now report that GTP-bound Gem interacts with the membrane-cytoskeleton linker protein Ezrin in its active state, and that Gem binds to active Ezrin in cells. The coexpression of Gem and Ezrin induces cell elongation accompanied by the disappearance of actin stress fibers and collapse of most focal adhesions.

Activation of membrane androgen receptors potentiates the antiproliferative effects of paclitaxel on human prostate cancer cells.

Genomic signaling mechanisms require a relatively long time to get into action and represent the main way through which steroid hormones affect target cells. In addition, steroids may rapidly activate cellular functions by non-genomic signaling mechanisms involving membrane sites. Understanding in depth the molecular mechanisms of the non-genomic action represents an important frontier for developing new and more selective pharmacologic tools for endocrine therapies.

Activation of membrane estrogen receptors induce pro-survival kinases.

Experimental and epidemiological data suggest a neuroprotective role for estrogen (E(2)). We have recently shown that, in PC12 cells, non-permeable estradiol conjugated to bovine serum albumin (BSA) prevent serum-deprivation induced apoptosis through activation of specific membrane estrogen receptors (mER). In the present study, we explored in detail the early signaling events involved in this anti-apoptotic action, downstream to activation of mER.

RalB mobilizes the exocyst to drive cell migration.

The Ras family GTPases RalA and RalB have been defined as central components of the regulatory machinery supporting tumor initiation and progression. Although it is known that Ral proteins mediate oncogenic Ras signaling and physically and functionally interact with vesicle trafficking machinery, their mechanistic contribution to oncogenic transformation is unknown. Here, we have directly evaluated the relative contribution of Ral proteins and Ral effector pathways to cell motility and directional migration.

Membrane androgen receptor activation induces apoptotic regression of human prostate cancer cells in vitro and in vivo.

Nongenomic androgen actions imply mechanisms different from the classical intracellular androgen receptor (iAR) activation. We have recently reported the identification of a membrane androgen receptor (mAR) on LNCaP human prostate cancer cells, mediating testosterone signal transduction within minutes. In the present study we provide evidence that activation of mAR by nonpermeable, BSA-coupled testosterone results in 1) inhibition of LNCaP cell growth (with a 50% inhibitory concentration of 5.

Opioid-somatostatin interactions in regulating cancer cell growth.

Opioids and somatostatin mediate their cellular effects through specific membrane receptors. Three major receptor classes (delta, mu and kappa) were identified for opioids, while for somatostatin, five different receptor classes (SSTR1-5) have been cloned. Through the interaction with their receptors, opioids and somatostatin exert their effects on cell growth, proliferation, differentiation and secretion.

Estrogen exerts neuroprotective effects via membrane estrogen receptors and rapid Akt/NOS activation.

The neuroprotective role of estrogen (E2) is supported by a multitude of experimental and epidemiological data, although its mode of action is not fully understood. The present work was conducted to study the underlying mechanisms of its neuroprotective action, using the rat cell line PC12, an established model for neuronal cell apoptosis and survival. Our results show that E2 (but not androgens or progestins) prevent growth inhibition and apoptosis of PC12 cells, induced by serum deprivation.

The opioid agonist ethylketocyclazocine reverts the rapid, non-genomic effects of membrane testosterone receptors in the human prostate LNCaP cell line.

Neuropeptides influence cancer cell replication and growth. Opioid peptides, and opiergic neurons are found in the prostate gland, and they are proposed to exert a role in tumor regulation, influencing cancer cell growth, as opioid agonists inhibit cell growth in several systems, including the human prostate cancer cell line LNCaP. In the same cell line, the existence of membrane testosterone receptors was recently reported, which increase, in a non-genomic manner, the secretion of PSA, and modify actin cytoskeleton dynamics, through the signaling cascade FAK-->PI-3 kinase-->Cdc42/Rac1.

Antiproliferative and apoptotic effects of selective phenolic acids on T47D human breast cancer cells: potential mechanisms of action.

Introduction: The oncoprotective role of food-derived polyphenol antioxidants has been described but the implicated mechanisms are not yet clear. In addition to polyphenols, phenolic acids, found at high concentrations in a number of plants, possess antioxidant action. The main phenolic acids found in foods are derivatives of 4-hydroxybenzoic acid and 4-hydroxycinnamic acid.

The human prostate cancer cell line LNCaP bears functional membrane testosterone receptors that increase PSA secretion and modify actin cytoskeleton.

Recent findings have shown that, in addition to the genomic action of steroids, through intracellular receptors, short-time effects could be mediated through binding to membrane sites. In the present study of prostate cancer LNCaP cells, we report that dihydrotestosterone and the non-internalizable analog testosterone-BSA increase rapidly the release of prostate-specific antigen (PSA) in the culture medium. Membrane testosterone binding sites were identified through ligand binding on membrane preparations, flow cytometry, and confocal laser microscopy of the non-internalizable fluorescent analog testosterone-BSA-FITC, on whole cells.