Crosstalk of Notch with p53 and p63 in cancer growth control.

Understanding the complexity of cancer depends on an elucidation of the underlying regulatory networks, at the cellular and intercellular levels and in their temporal dimension. This Opinion article focuses on the multilevel crosstalk between the Notch pathway and the p53 and p63 pathways. These two coordinated signalling modules are at the interface of external damaging signals and control of stem cell potential and differentiation. Positive or negative reciprocal regulation of the two pathways can vary with cell type and cancer stage. Therefore, selective or combined targeting of the two pathways could improve the efficacy and reduce the toxicity of cancer therapies.

Chemokines induce axon outgrowth downstream of Hepatocyte Growth Factor and TCF/β-catenin signaling

Axon morphogenesis is a complex process regulated by a variety of secreted molecules, including morphogens and growth factors, resulting in the establishment of the neuronal circuitry. Our previous work demonstrated that growth factors [Neurotrophins (NT) and Hepatocyte Growth Factor (HGF)] signal through β-catenin during axon morphogenesis. HGF signaling promotes axon outgrowth and branching by inducing β-catenin phosphorylation at Y142 and transcriptional regulation of T-Cell Factor (TCF) target genes. Here, we asked which genes are regulated by HGF signaling during axon morphogenesis. An array screening indicated that HGF signaling elevates the expression of chemokines of the CC and CXC families. In line with this, CCL7, CCL20, and CXCL2 significantly increase axon outgrowth in hippocampal neurons. Experiments using blocking antibodies and chemokine receptor antagonists demonstrate that chemokines act downstream of HGF signaling during axon morphogenesis. In addition, qPCR data demonstrates that CXCL2 and CCL5 expression is stimulated by HGF through Met/b-catenin/TCF pathway. These results identify CC family members and CXCL2 chemokines as novel regulators of axon morphogenesis downstream of HGF signaling.

The role of fibroblast growth factor (FGF) and type beta transforming growth factot beta (TGF beta1, beta2 and beta3) during rat craniofacial development

Growth factors seem to be part of a complex cellular signalling language, in which individual growth factors are the equivalents of the letters that compose words. According to this analogy, informational content lies, not in an individual growth factor, but in the entire set of growth factors and others signals to which a cell is exposed. The ways in which growth factors exert their combinatorial effects are becoming clearer as the molecular mechanisms of growth factors actions are being investigated. A number of related extracellular signalling molecules that play widespread roles in regulating development in both invertebrates and vertebrates constitute the Fibroblast Growth Factor (FGF) and type beta Transforming Growth Factor ((TGF beta). The latest research literature about the role and fate of these Growth factors and their influence in the craniofacial bone growth ad development is reviewed

The role of fibroblast growth factor (FGF) and type beta transforming growth factot beta (TGF beta1, beta2 and beta3) during rat craniofacial development

Growth factors seem to be part of a complex cellular signalling language, in which individual growth factors are the equivalents of the letters that compose words. According to this analogy, informational content lies, not in an individual growth factor, but in the entire set of growth factors and others signals to which a cell is exposed. The ways in which growth factors exert their combinatorial effects are becoming clearer as the molecular mechanisms of growth factors actions are being investigated. A number of related extracellular signalling molecules that play widespread roles in regulating development in both invertebrates and vertebrates constitute the Fibroblast Growth Factor (FGF) and type beta Transforming Growth Factor ((TGF beta). The latest research literature about the role and fate of these Growth factors and their influence in the craniofacial bone growth ad development is reviewed

The antilipolytic effect of insulin and epidermal growth factor in rat adipocytes are mediated by different mechanisms

Epidermal growth factor (EGF) and insulin induced similar effects in isolated rat adipocytes. To determine whether EGF and insulin produced similar effects through the same mechanisms, we focused on lipolysis. Insulin inhibited the lipolysis stimulated by isoproterenol, glucagon (either alone or in combination with adenosine deaminase), adenosine deaminase itself, or forskolin. In contrast, EGF did not inhibit the lipolysis stimulated by forskolin or by hormones when the cells were also incubated with adenosine deaminase. The effect of insulin, but not that of EGF, on isoproterenol-stimulated lipolysis disappeared when adipocytes were incubated with 1 microM wortmannin. These results indicate that EGF and insulin affected lipolysis through different mechanisms. We observed that EGF, but not insulin, increased cytosolic Ca2+. The effect of EGF, but not that of insulin, disappeared when the cells were incubated in a Ca2+-free medium. We suggest that EGF, but not insulin, mediate its antilipolytic effect through a Ca2+-dependent mechanism which, however, do not involve Ca2+-activated protein kinase C isoforms. This is based on the following: 1) phorbol 12-myristate 13-acetate affected lipolysis in an opposite way to that of EGF; and 2) the protein kinase C inhibitor bisindolylmaleimide GF 109203X did not affect the antilipolytic action of EGF. Our results indicate that the antilipolytic effect of EGF resembles more that of vasopressin than that of insulin.

Development of an epidermal growth factor derivative with EGFR blocking activity.

The members of the epidermal growth factor (EGF)/ErbB family are prime targets for cancer therapy. However, the therapeutic efficiency of the existing anti-ErbB agents is limited. Thus, identifying new molecules that inactivate the ErbB receptors through novel strategies is an important goal on cancer research. In this study we have developed a shorter form of human EGF (EGFt) with a truncated C-terminal as a novel EGFR inhibitor. EGFt was designed based on the superimposition of the three-dimensional structures of EGF and the Potato Carboxypeptidase Inhibitor (PCI), an EGFR blocker previously described by our group. The peptide was produced in E. coli with a high yield of the correctly folded peptide. EGFt showed specificity and high affinity for EGFR but induced poor EGFR homodimerization and phosphorylation. Interestingly, EGFt promoted EGFR internalization and translocation to the cell nucleus although it did not stimulate the cell growth. In addition, EGFt competed with EGFR native ligands, inhibiting the proliferation of cancer cells. These data indicate that EGFt may be a potential EGFR blocker for cancer therapy. In addition, the lack of EGFR-mediated growth-stimulatory activity makes EGFt an excellent delivery agent to target toxins to tumours over-expressing EGFR.

Involvement of a transforming-growth-factor-beta-like molecule in tumor-cell-derived inhibition of nitric-oxide synthesis in cerebral endothelial cells.

Nitric oxide (NO) has been shown to exert cytotoxic effects on tumor cells. We have reported that EC219 cells, a rat-brain-microvessel-derived endothelial cell line, produced NO through cytokine-inducible NO synthase (iNOS), the induction of which was significantly decreased by (a) soluble factor(s) secreted by DHD/PROb, an invasive sub-clone of a rat colon-carcinoma cell line. In this study, the DHD/PROb cell-derived NO-inhibitory factor was characterized. Northern-blot analysis demonstrated that the induction of iNOS mRNA in cytokine-activated EC219 cells was decreased by PROb-cell-conditioned medium. When DHD/PROb cell supernatant was fractionated by affinity chromatography using Con A-Sepharose or heparin-Sepharose, the NO-inhibitory activity was found only in Con A-unbound or heparin-unbound fractions, respectively, indicating that the PROb-derived inhibitory factor was likely to be a non-glycosylated and non-heparin-binding molecule. Pre-incubation of DHD/PROb-cell supernatant with anti-TGF-beta neutralizing antibody completely blocked the DHD/PROb-derived inhibition of NO production by EC219 cells. Addition of exogenous TGF-beta 1 dose-dependently inhibited NO release by EC219 cells. The presence of active TGF-beta in the DHD/PROb cell supernatant was demonstrated using a growth-inhibition assay. Moreover, heat treatment of medium conditioned by the less invasive DHD/REGb cells, which constitutively secreted very low levels of active TGF-beta, increased both TGF-beta activity and the ability to inhibit NO production in EC219 cells. Thus, DHD/PROb colon-carcinoma cells inhibited NO production in EC219 cells by secreting a factor identical or very similar to TGF-beta.

Epidermal growth factor secreted from submandibular salivary glands interferes with the lipolytic effect of adrenaline in mice

We had described that epidermal growth factor (EGF) interfered with the lipolytic effect of catecholamines in isolated adipocytes. Since catecholamines stimulate the release of EGF from submandibular salivary glands to blood plasma in male mice, we studied whether EGF affected also the lipolytic response to adrenaline in whole animals. We studied the effect of adrenaline in sialoadenectomized and sham-operated mice receiving or not a high dose of EGF following adrenaline injection. There was no difference in plasma EGF concentration between sham-operated and sialoadenectomized animals receiving saline. After adrenaline administration plasma EGF increased by 20-fold in sham-operated but did not increase in sialoadenectomized mice. Indeed, the increase was much higher (more than 100-fold) in mice receiving exogenous EGF. The effect of adrenaline on plasma concentration of both glycerol and nonesterified fatty acids was higher as lower was plasma EGF concentration. Isolated adipocytes obtained from sham-operated or sialoadenectomized mice had identical lipolytic response to adrenaline. The lipolytic response of adipocytes to isoproterenol was decreased by addition of EGF. To study whether the interference with the in vivo lipolytic effect of adrenaline had further metabolic consequences, we measured plasma b-hydroxybutyrate concentration in plasma. There was no difference in the response to adrenaline between sham-operated and sialoadenectomized mice in spite of the difference in plasma nonsterified fatty acid concentration. Studies in isolated hepatocytes indicated that ketogenesis run at near maximal rate in this range of substrate concentration. These results suggest that EGF in the physiological range decreases the lipolytic effect of adrenaline but does not compromise further metabolic events like the enhancement of ketogenesis.

Insulin-Like growth-factor 1 myocardial expression decreases in chronic alcohol consumption

Background Chronic alcohol ingestion may cause severe biochemical and pathophysiological derangements to skeletal muscle. Unfortunately, these alcohol-induced events may also prime skeletal muscle for worsened, delayed, or possibly incomplete repair following acute injury. As alcoholics may be at increased risk for skeletal muscle injury, our goals were to identify the effects of chronic alcohol ingestion on components of skeletal muscle regeneration. To accomplish this, age- and gender-matched C57Bl/6 mice were provided normal drinking water or water that contained 20% alcohol (v/v) for 18-20 wk. Subgroups of mice were injected with a 1.2% barium chloride (BaCl2) solution into the tibialis anterior (TA) muscle to initiate degeneration and regeneration processes. Body weights and voluntary wheel running distances were recorded during the course of recovery. Muscles were harvested at 2, 7 or 14 days post-injection and assessed for markers of inflammation and oxidant stress, fiber cross-sectional areas, levels of growth and fibrotic factors, and fibrosis. Results Body weights of injured, alcohol-fed mice were reduced during the first week of recovery. These mice also ran significantly shorter distances over the two weeks following injury compared to uninjured, alcoholics. Injured TA muscles from alcohol-fed mice had increased TNFα and IL6 gene levels compared to controls 2 days after injury. Total protein oxidant stress and alterations to glutathione homeostasis were also evident at 7 and 14 days after injury. Ciliary neurotrophic factor (CNTF) induction was delayed in injured muscles from alcohol-fed mice which may explain, in part, why fiber cross-sectional area failed to normalize 14 days following injury. Gene levels of TGFβ1 were induced early following injury before normalizing in muscle from alcohol-fed mice compared to controls. However, TGFβ1 protein content was consistently elevated in injured muscle regardless of diet. Fibrosis was increased in injured, muscle from alcohol-fed mice at 7 and 14 days of recovery compared to injured controls. Conclusions Chronic alcohol ingestion appears to delay the normal regenerative response following significant skeletal muscle injury. This is evidenced by reduced cross-sectional areas of regenerated fibers, increased fibrosis, and altered temporal expression of well-described growth and fibrotic factors.

Dual activation of pathways regulated by steroid receptors and peptide growth factors in primary prostate cancer revealed by Factor Analysis of microarray data

Background: We use an approach based on Factor Analysis to analyze datasets generated for transcriptional profiling. The method groups samples into biologically relevant categories, and enables the identification of genes and pathways most significantly associated to each phenotypic group, while allowing for the participation of a given gene in more than one cluster. Genes assigned to each cluster are used for the detection of pathways predominantly activated in that cluster by finding statistically significant associated GO terms. We tested the approach with a published dataset of microarray experiments in yeast. Upon validation with the yeast dataset, we applied the technique to a prostate cancer dataset. Results: Two major pathways are shown to be activated in organ-confined, non-metastatic prostate cancer: those regulated by the androgen receptor and by receptor tyrosine kinases. A number of gene markers (HER3, IQGAP2 and POR1) highlighted by the software and related to the later pathway have been validated experimentally a posteriori on independent samples. Conclusion: Using a new microarray analysis tool followed by a posteriori experimental validation of the results, we have confirmed several putative markers of malignancy associated with peptide growth factor signalling in prostate cancer and revealed others, most notably ERRB3 (HER3). Our study suggest that, in primary prostate cancer, HER3, together or not with HER4, rather than in receptor complexes involving HER2, could play an important role in the biology of these tumors. These results provide new evidence for the role of receptor tyrosine kinases in the establishment and progression of prostate cancer.

Le sentiment de gratitude en soins palliatifs : un facteur contribuant au bien-être et à la qualité de vie ? [Gratitude in palliative care: is it a psychological factor contributing to well-being and quality of life?]

En s'appuyant sur la littérature scientifique et l'état de la recherche, cet article a pour objectif de montrer pourquoi la prise en compte du sentiment de gratitude peut s'avérer utile dans le contexte palliatif en mettant en évidence dans quelle mesure cette émotion ou disposition individuelle: 1) entre en résonance avec le concept de croissance posttraumatique et certains enjeux relationnels chez les patients en fin de vie; 2) représente un facteur favorisant le bien-être et la qualité de vie; 3) peut être considérée comme un facteur protecteur contre les troubles psychopathologiques. Based on the scientific literature and the state of research, this article aims to show why the feeling of gratitude may represent a point of interest for palliative care. We will highlight the following in this article: 1) why this feeling of gratitude resonates with the concept of post-traumatic growth and relational challenges in end-of-life patients; 2) in which measure this feeling represents a factor contributing to well-being and quality of life; 3) in which measure this feeling may be considered as a protective factor against psychopathological troubles.

Secondary growth of the Arabidopsis hypocotyl-vascular development in dimensions.

The secondary thickening of plant organs in extant dicotyledons is a massive growth process that constitutes the major carbon sink in perennial, woody plants. Yet, our understanding of its molecular genetic control has been mostly obtained by its analysis in an herbaceous annual model, Arabidopsis. Recent years have seen increased interest in this somewhat under-researched topic, and various (non-)cell autonomous factors that guide the extent and vascular patterning of secondary growth have been identified. Concomitantly, a more detailed understanding of vascular differentiation processes has been obtained through analyses of primary growth, mostly in the root meristem. A future challenge will be the integration of these patterning and differentiation modules together with cambial activity into the 4-dimensional frame of secondary thickening.

Factors Regulating Chondrogenic Differentiation

Chondrogenesis is a co-ordinated differentiation process in which mesenchymal cells condensate, differentiate into chondrocytes and begin to secrete molecules that form the extracellular matrix. It is regulated in a spatio-temporal manner by cellular interactions and growth and differentiation factors that modulate cellular signalling pathways and transcription of specific genes. Moreover, post-transcriptional regulation by microRNAs (miRNAs) has appeared to play a central role in diverse biological processes, but their role in skeletal development is not fully understood. Mesenchymal stromal cells (MSCs) are multipotent cells present in a variety of adult tissues, including bone marrow and adipose tissue. They can be isolated, expanded and, under defined conditions, induced to differentiate into multiple cell lineages including chondrocytes, osteoblasts and adipocytes in vitro and in vivo. Owing to their intrinsic capability to self-renew and differentiate into functional cell types, MSCs provide a promising source for cell-based therapeutic strategies for various degenerative diseases, such as osteoarthritis (OA). Due to the potential therapeutic applications, it is of importance to better understand the MSC biology and the regulatory mechanisms of their differentiation. In this study, an in vitro assay for chondrogenic differentiation of mouse MSCs (mMSCs) was developed for the screening of various factors for their chondrogenic potential. Conditions were optimized for pellet cultures by inducing mMSC with different bone morphogenetic proteins (BMPs) that were selected based on their known chondrogenic relevance. Characterization of the surface epitope profile, differentiation capacity and molecular signature of mMSCs illustrated the importance of cell population composition and the interaction between different populations in the cell fate determination and differentiation of MSCs. Regulation of Wnt signalling activity by Wnt antagonist sFRP-1 was elucidated as a potential modulator of lineage commitment. Delta-like 1 (dlk1), a factor regulating adipogenesis and osteogenesis, was shown to exhibit stage-specific expression during embryonic chondrogenesis and identified as a novel regulator of chondrogenesis, possibly through mediating the effect of TGF-beta1. Moreover, miRNA profiling demonstrated that MSCs differentiating into a certain lineage exhibit a specific miRNA expression profile. The complex regulatory network between miRNAs and transcription factors is suggested to play a crucial role in fine-tuning the differentiation of MSCs. These results demonstrate that commitment of mesenchymal stromal cells and further differentiation into specific lineages is regulated by interactions between MSCs, various growth and transcription factors, and miRNA-mediated translational repression of lineage-specific genes.