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Spermatogonial stem cells (SSCs) have been used for the production of transgenic animals and for the recovery of male fertility. However, the proliferation of SSCs in vitro is still immature, and the mechanisms and pathways involved in the proliferation of SSCs are not clear. Here, the effects of platelet-derived growth factor-BB (PDGF-BB) and epidermal growth factor (EGF) on the proliferation of dairy goat SSCs in vitro were detected. The results showed that 20 ng/ml PDGF-BB or 25 ng/ml EGF was the optimum concentration, and that the BCL2 in the experimental groups was significantly higher than that in the control (P < 0.05), while BAX and BAD were dramatically downregulated (P < 0.05). The pERK1/2 in the experimental groups was about 3–5 times higher than that in the control. After the specific MEK1/2 inhibitor was added, BCL2 was reduced significantly (P < 0.001), while BAX and BAD were upregulated (P < 0.001). The expression of pERK1/2 decreased by 10%–30%. We speculated that these two growth factors may be mediated through the Ras/ERK1/2 signaling pathway to regulate the expression of pERK1/2 protein, and thus enhance the resistance of SSCs to apoptosis. However, further studies are needed to verify this hypothesis. • PDGF-BB and EGF will be of great benefit to short-term in-vitro culture of goat SSCs. • PDGF-BB and EGF can trigger the expression of BCL2 and suppress the expression of BAD and BAX. • PDGF-BB and EGF may be mediated through the Ras/ERK1/2 signaling pathway to enhance the resistance of SSCs to apoptosis. [ABSTRACT FROM AUTHOR]

Keywords: epidermal growth factor (EGF); heparin-binding EGF-like growth factor; pre-analytical conditions; sample storage; stability; tubular damage markers UEGF, urinary epidermal growth factor; uHB-EGF, urinary heparin-binding EGF-like growth factor; h, hour(s); M, month(s); FT, freeze-thaw cycles; QC, quality control. UEGF, urinary epidermal growth factor; uHB-EGF, urinary heparin-binding EGF-like growth factor; h, hour(s), M, months. However, uHB-EGF levels in QCs measured in the same run were also lower compared to baseline indicating that the change in uHB-EGF was actually the result of day-to-day variability in the uHB-EGF measurement. [Extracted from the article]

The potential of Human Platelet Lysate (hPL) as animal serum replacement in various cell type has been reported. In HUVECs culture system, exogenous growth factors are routinely added to the media. It is currently unknown whether the presence of hPL in the medium could eliminate the need for exogenous growth factors in HUVECs culture system. This study aimed to evaluate the effect of hPL in HUVECs culture without additional EGF and bFGF, two commonly uses growth factors in HUVECs culture medium. HUVECs proliferation and protein profile was tested with MTT assay and SDS PAGE, respectively. The expression of CD34, CD106 proteins were analyzed by FACS. HUVECs cell proliferation was significantly decreased in the 2% hPL group without additional EGF and bFGF (p<0.05). However, no significant difference was found in the control group with 5% hPL without additional EGF and bFGF. Protein profile, the expression of CD34 and CD106 were comparable in all group tested. In the absence of routinely used growth factors in the HUVECs media, hPL could still support the growth of HUVECs. In addition to hPL role as serum replacement in the cell culture system, hPL can be used as an alternate of exogenous growth factors in HUVECs culture. [ABSTRACT FROM AUTHOR]

Abstract: Lysophosphatidic acid (LPA) is a growth factor for many cells including prostate and ovarian cancer-derived cell lines. LPA stimulates H2O2 production which is required for growth. However, there are significant gaps in our understanding of the spatial and temporal regulation of H2O2-dependent signaling and the way in which signals are transmitted following receptor activation. Herein, we describe the use of two reagents, DCP-Bio1 and DCP-Rho1, to evaluate the localization of active protein oxidation after LPA stimulation by detection of nascent protein sulfenic acids. We found that LPA stimulation causes internalization of LPA receptors into early endosomes that contain NADPH oxidase components and are sites of H2O2 generation. DCP-Rho1 allowed visualization of sulfenic acid formation, indicative of active protein oxidation, which was stimulated by LPA and decreased by an LPA receptor antagonist. Protein oxidation sites colocalized with LPAR1 and the endosomal marker EEA1. Concurrent with the generation of these redox signaling-active endosomes (redoxosomes) is the H2O2- and NADPH oxidase-dependent oxidation of Akt2 and PTP1B detected using DCP-Bio1. These new approaches therefore enable detection of active, H2O2-dependent protein oxidation linked to cell signaling processes. DCP-Rho1 may be a particularly useful protein oxidation imaging agent enabling spatial resolution due to the transient nature of the sulfenic acid intermediate it detects. [Copyright &y& Elsevier]

Background: Acute kidney injury (AKI) increases the morbidity of critically ill children. Thus, it is necessary to identify better renal biomarkers to follow the outcome of these patients. This prospective case-control study explored the clinical value of a urinary biomarker profile comprised of neutrophil gelatinase lipocalin (uNGAL), fibroblast growth factor-2 (uFGF-2), and epidermal growth factor (uEGF) to follow these patients. Methods: Urine samples were collected from 21 healthy children, and 39 critically ill children (mean age 7.5 years ± 6.97 SD) admitted to a pediatric intensive care unit with sepsis or requiring extra corporeal membrane oxygenation (ECMO). uNGAL, uFGF-2, and uEGF levels were measured using ELISA kits during the first 24 h of admission to PICU, at peak of illness, and upon resolution of the critical illness. Results: On admission, the uNGAL and uFGF-2 levels were increased, and the uEGF levels were decreased, in critically ill children with AKI ( n = 19) compared to those without AKI ( n = 20), and healthy controls. A biomarker score using the combined cut-off values of uNGAL, uFGF-2, and uEGF (AUC = 0.90) showed the highest specificity to identify children with AKI, relative to each biomarker alone. uNGAL and uFGF-2 on admission showed high sensitivity and specificity to predict mortality (AUC = 0.82). Conclusions: The biomarker profile comprised of uNGAL, uFGF-2, and uEGF increased the specificity to detect AKI in critically ill children, when compared to each biomarker used alone. uNGAL and uFGF-2 may also predict the risk of death. Further validation of these findings in a large sample size is warranted. [ABSTRACT FROM AUTHOR]

Highlights: [•] HB-EGF expression was increased during the development of liver fibrosis. [•] Conditional HB-EGF knockout mouse showed enhanced experimental liver fibrosis. [•] HB-EGF antagonized TGF-β-induced activation of hepatic stellate cells. [•] We report a possible protective role of HB-EGF in cholestatic liver fibrosis. [ABSTRACT FROM AUTHOR]

Management of diabetic foot ulcers remains a rather challenging task. Epidermal growth factor (EGF) plays a central role in wound healing. It acts on epithelial cells and fibroblasts promoting restoration of damaged epithelium. However, its bioavailability is impaired in chronic diabetic foot ulcers. Current evidence suggests that application of human recombinant EGF in addition to standard treatment is able to achieve both partial and complete healing and to prevent foot amputations. Its efficacy has been tested at various concentrations and by various administration routes (topical application and intralesional injection). Intralesional injection has better availability on the deep wound layers, but pain at the injection site is a common complaint. Generally, adverse events have been minor to mild. Finally, numerous issues need to be further clarified before widespread use of EGF becomes possible in everyday practice. Such issues include optimal dosage and administration route, characteristics of the ulcers most likely to heal (severity and ischemic/neuropathic or both), and cost-effectiveness. [ABSTRACT FROM PUBLISHER]

Abstract: Extracellular signal-regulated kinases (ERKs) play important physiological roles in proliferation, differentiation and gene expression. ERK5 is twice the size of ERK1/2, the amino-terminal half contains the kinase domain that shares the homology with ERK1/2 and TEY activation motif, whereas the carboxy-terminal half is unique. In this study, we examined the cross-talk mechanism between G-protein-coupled receptors (GPCRs) and receptor tyrosine kinases, focusing on ERK1/2 and 5. The pretreatment of rat pheochromocytoma cells (PC12) with pertussis toxin (PTX) specifically enhanced epidermal growth factor (EGF)-induced ERK5 phosphorylation. In addition, lysophosphatidic acid (LPA) attenuated the EGF-induced ERK5 phosphorylation in LPA1 receptor- and Gi/o-dependent manners. On the other hand, LPA alone activated ERK1/2 via Gβγ subunits and Ras and potentiated EGF-induced ERK1/2 phosphorylation at late time points. These results suggest Gi/o negatively regulates ERK5, while it positively regulates ERK1/2. LPA did not affect cAMP levels after EGF treatment, and the reagents promoting cAMP production such as forskolin and cholera toxin also attenuated the EGF-induced ERK5 phosphorylation, indicating that the inhibitory effect of LPA on ERK5 inhibition via Gi/o is not due to inhibition of adenylyl cyclase by Gαi/o. However, the inhibitory effect of LPA on ERK5 was abolished in PC12 cells stably overexpressing C-terminus of GPCR kinase2 (GRK2), and overexpression of Gβ1 and γ2 subunits also suppressed ERK5 phosphorylation by EGF. In response to LPA, Gβγ subunits interacted with EGF receptor in a time-dependent manner. These results strongly suggest that LPA negatively regulates the EGF-induced ERK5 phosphorylation through Gβγ subunits. [Copyright &y& Elsevier]

Abstract: We report here the generation and characterization of EGF-IL-18 fusion protein as an anti-tumor reagent. The epidermal growth factor (EGF) and interleukin-18 (IL-18) fusion protein was shown to induce interferon-γ (IFNγ) expression and secretion in KG-1 cells, and to promote PBMNC proliferation. It also stimulated activation of CD4+ T cells, and increased other immune responses. Moreover, EGF-IL-18 could induce significant tumor regression in SMMC-7721-xenografted Balb/c nude mice when administered together with peritumoral injection of X-ray-irradiated NK-92 cells, and this regression is associated with arresting of the tumor cells in G1 phase and induction of apoptosis. [Copyright &y& Elsevier]

Abstract: The protein kinase Akt is a critical regulator of cell function and its overexpression and activation have been functionally linked to numerous pathologies such as cancer. Previous reports regarding the mechanism-regulating Akt’s activation have revealed two phosphorylation events, at threonine 308 (T308) and serine 473 (S473), as necessary for the full activation of the kinase in response to insulin. For this reason and because of the availability of phospho-specific antibodies to both T308 and S473, many studies that focus on Akt’s role in governing cell function rely on the measurement of these two sites to understand changes in kinase activity. Recent evidence, however, suggests the involvement of other phosphorylation sites; for example, in Src-transformed and epidermal growth factor (EGF)-treated cells, tyrosine phosphorylation has been found important for full kinase activation. In this study, we probed the quantitative reliability of using S473 and/or T308 phosphorylation as surrogates for Akt kinase activity across diverse treatment conditions. We performed quantitative Western blots and kinase activity assays on lysates generated during a 2h time course from two cell lines treated with either EGF or insulin. From the resulting ∼250 quantitative measurements of phosphorylation and activity, we found that both T308 and S473 phosphorylation accurately captured quantitative changes in EGF-stimulated cells, but not in insulin-stimulated cells. Moreover, in all but one condition studied, we found a tight correlation between the onset of phosphorylation and dephosphorylation for both sites, despite the fact that they do not share common kinase- or phosphatase-mediated regulation. In sum, using a quantitative approach to study Akt activation identified ligand-dependent limits for the use of T308 or S473 as proxies for kinase activity and suggests the coregulation of Akt phosphorylation and dephosphorylation. [Copyright &y& Elsevier]

Abstract: The epidermal growth factor (EGF) and EGF receptor (EGFR) family are often overexpressed in various human cancers including ovarian cancer. While it is generally believed that reactive oxygen species (ROS) are involved in the intracellular signaling events, the role of ROS in EGF-induced angiogenesis and carcinogenesis remains to be elucidated. The present study investigated the role of ROS in the regulation of AKT, p70S6K1, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1 (HIF-1) in ovarian cancer cells. In this study, OVCAR-3 cells were treated with EGF and catalase, an H2O2 scavenger. EGF treatment increases H2O2 production, leading to activation of the AKT/p70S6K1 pathway, resulting in increased VEGF expression at the transcriptional level. The inhibition of H2O2 production by catalase abolished EGF-induced AKT and p70S6K1 activation, and VEGF expression through HIF-1α expression. Forced expression of p70S6K1 and HIF-1α reversed catalase- and rapamycin-inhibited VEGF transcriptional activation. We also showed that rapamycin, p70S6K1 inhibitor and catalase overexpression inhibited tumor angiogenesis. This study demonstrates a novel mechanism of EGF-induced VEGF and HIF-1α expression through production of H2O2 and activation of AKT and p70S6K1 in human ovarian cancer cells. This study also indicates that p70S6K1 and H2O2 are important in tumor angiogenesis. The results of the study could have an important implication in ovarian cancer therapy. [Copyright &y& Elsevier]

In this study we show that decidua conditioned media (DCM) downregulate Connexin 40 (Cx40) expression in extravillous trophoblast (EVT) outgrowths and can promote EVT differentiation to the invasive phenotype resulting in switching of integrin and EGF receptor expression. This suggests that growth factors secreted by the decidua, such as EGF, mediate trophoblast migration/invasion and may do so by modulating Cx40 expression and function. To test this hypothesis we have utilized migration assays using cell lines expressing Cx40. Migration assays were performed with Jeg-3, Jeg-3 overexpressing Cx40 (JpUHD) and JAR cells seeded on fibronectin-coated inserts with 8μm pores and incubated in the absence or presence of serum-starved decidual cells. Cell migration was only observed in the presence of DCM. Conversely overexpression of Cx40 in Jeg-3 cells resulted in inhibition of cell migration as compared to wild-type control. Addition of DCM to cultured JAR cells resulted in the downregulation of Cx40 protein. EGF is known to stimulate trophoblast migration/invasion and was detected in DCM; therefore, we investigated the action of EGF on Cx40. EGF (10ng/mL) resulted in the downregulation of Cx40 in the JAR cell line. However, EGF had no effect on JAR cell migration. We conclude that decidual secretion of growth factors, such as EGF, may act to prime trophoblast for migration/invasion through modulation of connexin expression and function. [Copyright &y& Elsevier]

Summary: Growth factors and cytokines are the vital mediators of both normal physiological and pathophysiological processes. This review will highlight the contrasting effects of certain growth factors and cytokines involved in a normal physiological process such as wound healing and in a pathological condition such as atherosclerosis. In addition, this review will also discuss the future of these signalling molecules in wound healing and atherosclerosis research. [Copyright &y& Elsevier]

Purpose : To study survival of cultured U-343MGaCl 2:6 glioma cells after incubation with boron-containing liposomes targeting the epidermal growth factor receptor following neutron irradiation. Materials and methods : Epidermal growth factor-tagged liposomes were loaded with water-soluble boronated acridine developed for boron neutron capture therapy, (BNCT). Cellular uptake and distribution were studied. Further, cells were placed at 3 cm depth in a phantom and exposed to an epithermal neutron beam to study clonogenic cell survival. Results : The cellular uptake of boron reached 90 ppm and it was determined by subcellular fractionation that most of the cell-associated boron was located outside of the nucleus. For clonogenic survival, the cells were incubated with epidermal growth factor receptor-targeted liposomes for 4 hours resulting in a cellular concentration of 55 ppm boron (11 ppm 10 B). At a fluence of 3 × 10 12 neutrons/cm 2 the cell killing effect of the boron-containing epidermal growth factor-liposomes was about ten times higher than for neutrons only. Furthermore, theoretical calculation of the survival by enriched compound (55 ppm 10 B), using the parameters from non-enriched compound (11 ppm 10 B), shows that the killing effect in this case would be approximately five orders of magnitude higher than for neutrons only. Conclusion : The results in this study show that epidermal growth factor-receptor targeted liposomes are suitable as tumor-cell delivery agents of boron for BNCT and support further studies to demonstrate their effectiveness in vivo . [ABSTRACT FROM AUTHOR]

Abstract: The effects of i.c.v. infused platelet-derived growth factor and brain-derived neurotrophic factor on cell genesis, as assessed with bromodeoxyuridine (BrdU) incorporation, were studied in adult rats with unilateral 6-hydroxydopamine lesions. Both growth factors increased the numbers of newly formed cells in the striatum and substantia nigra to an equal extent following 10 days of treatment. At 3 weeks after termination of growth factor treatment, immunostaining of BrdU-labeled cells with the neuronal marker NeuN revealed a significant increase in newly generated neurons in the striatum. In correspondence, many doublecortin-labeled neuroblasts were also observed in the denervated striatum following growth factor treatment. Further evaluation suggested that a subset of these new neurons expresses the early marker for striatal neurons Pbx. However, no BrdU-positive cells were co-labeled with DARPP-32, a protein expressed by mature striatal projection neurons. Both in the striatum and in the substantia nigra there were no indications of any newly born cells differentiating into dopaminergic neurons following growth factor treatment, such that BrdU-labeled cells never co-expressed tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. In conclusion, our results suggest that administration of these growth factors is capable of recruiting new neurons into the striatum of hemiparkinsonian rats. [Copyright &y& Elsevier]

Abstract: A recent report demonstrated that serum levels of epidermal growth factor (EGF) were significantly decreased in patients with schizophrenia, suggesting that impaired EGF signaling might be associated with the pathophysiology of schizophrenia. Our goal in the present study was to determine whether serum levels of EGF are altered in patients with schizophrenia. We found that serum levels of EGF in drug-naive (n =15) or medicated patients (n =25) with schizophrenia did not differ from those of age- and sex-matched normal controls (n =40). However, we found a significant correlation between serum EGF levels and BPRS scores in the combined groups of patients. Therefore, our results do not support the claim that EGF plays a role in the pathogenesis of schizophrenia, but they suggest that EGF may serve as a state marker, that is, as an index of symptom-linked deficits. [Copyright &y& Elsevier]

Abstract: Extracellular glutamate levels increase as a consequence of perinatal hypoxia/ischemia, causing the death of neurons and oligodendrocytes. Precursors in the subventricular zone (SVZ) also die following perinatal hypoxia/ischemia; therefore we hypothesized that glutamate would stimulate the death of neural precursors. Here we demonstrate using calcium imaging that SVZ derived neural stem/progenitor cells respond to both ionotropic and metabotropic excitatory amino acids. Therefore, we tested the effects of high levels of glutamate receptor agonists on the proliferation, survival, and differentiation of SVZ derived neural stem/progenitor cells in vitro. We show that high levels of glutamate, up to 1 mM, are not toxic to neural precursor cultures. In fact, stimulation of either the kainate receptor or group 2 metabotropic glutamate receptors (group 2 mGluR) reduces basal levels of apoptosis and increases neural precursor proliferation. Furthermore, group 2 mGluR activation expands the number of multipotent progenitor cells present in these cultures while maintaining equivalent mature cell production. We conclude that the glutamate released following perinatal hypoxia/ischemia may act to acutely promote the proliferation of multipotent precursors in the subventricular zone. [Copyright &y& Elsevier]

Summary: Both cyclooxygenase (COX)-2 and epidermal growth factor receptor (EGFR) are thought to play important roles in the pathogenesis of non-small cell lung cancer (NSCLC). A number of in vitro studies have postulated a link between EGFR activation and subsequent COX-2 upregulation. The relationship between these factors has not been established in patients with NSCLC. COX-2 and EGFR expression were studied in 172 NSCLC specimens using standard immunohistochemical techniques. Western blotting was used to determine COX-2 and EGFR levels in five NSCLC cell lines. The effect of treatment with EGF on COX-2 expression in A549 cells was assessed. Results:: Both EGFR and COX-2 are overexpressed in NSCLC. The predominant pattern of COX-2 and EGFR staining was cytoplasmic. Membranous EGFR staining was seen in 23.3% of cases. There was no relationship between COX-2 and EGFR expression and survival or any clinicopathological features. No correlation was seen between EGFR expression and COX-2 expression in the immunohistochemical series or in the cell lines. Treatment with EGF did not upregulate COX-2 levels in A549 cells, either in serum free or serum-supplemented conditions. Conclusions:: Although COX-2 and EGFR are over-expressed in NSCLC neither was of prognostic significance in this series of cases. There is no correlation between these two factors in either tumour samples or cell lines. Although these factors show no correlation in NSCLC, they remain potential, though independent targets for treatment. [Copyright &y& Elsevier]

Abstract: Tetrahymena pyriformiswas treated with insulin, histamine or serotonin for 30 min and epidermal growth factor (EGF) level was studied inside the cells using specific antibodies and flow cytometry as well as confocal microscopy. The EGF concentration was highly significantly elevated after hormone treatment, regardless of the hormone used. EGF was localized mainly in the cortical region (mucocysts) and in vesicles and this localization did not differ in untreated and treated cells. The results call attention to the possibility of interactions between hormones at unicellular level and points to the presence of a hormonal system in Tetrahymena that includes receptors, hormones and signal transduction pathways as well as hormonal interactions. This could be the basis of further evolution to the hormonal system of multicellulars. [Copyright &y& Elsevier]

Abstract: Low incidence of cancer in schizophrenia is one of the interesting puzzles in psychiatric field over decades. Analysis of genetic difference between schizophrenia and lung cancer might provide us with possible clues to understand molecular mechanisms of pathophysiology of schizophrenia. Epidermal growth factor (EGF), one of the potent growth promoting factors, has been studied for its roles in cancer development. EGF is also known to be involved in cognitive function. In order to analyze the genetic difference between schizophrenia and lung cancer, polymorphism of EGF gene was studied from 174 schizophrenia patients, 122 lung cancer patients and 132 controls in Korean population. Genotype frequency analysis of EGF gene (AluI restriction site, 5′-UTR, rs4444903) in the EGF gene was studied. The genotype and allele frequencies of the AluI polymorphism showed significant differences between schizophrenia and lung cancer patients [p &#60;0.0001; p &#60;0.0001, odds ratio (95% CI), 0.3690 (0.2600–0.5236)]. When compared with controls, schizophrenia patients showed no significant differences from controls in genotype and allele frequencies [p =0.5151; p =0.3516, odds ratio (95% CI), 0.8589 (0.6235–1.1830)]. However, lung cancer patients showed significant differences from controls in genotype and allele frequencies [p &#60;0.0001; p &#60;0.0001, odds ratio (95% CI), 2.3275 (1.6082–3.3687)]. These results indicate that schizophrenia is not associated with AluI polymorphism of EGF gene and EGF gene polymorphism is different between schizophrenia and lung cancer patients. [Copyright &y& Elsevier]

Abstract: The vascular endothelial growth factor A (VEGF-A) is essential during embryonic development as inactivation of only one allele of its gene results in embryonic lethality. Up-regulation of VEGF under physiological situations allows for adaptation to hypoxic stress, to transient inflammatory processes, and to wounding. Its expression also increases all along the process of neovascularization of solid and hematological tumors. The object of this article is to focus on the transcriptional regulation of its gene. The major cis-acting sequences and trans-activating factors will be described as well as the physiological and pathological situations leading to the intervention of such sequences and factors. We will also focus on two transcription factors essential to VEGF gene transcription: the hypoxia-inducible factor-1, which is responsible for its increased by hypoxia, as well as Sp1, which is implicated in the response to various extracellular stimuli. [Copyright &y& Elsevier]

Abstract: To better understand growth regulation in the human parasitic cestode Echinococcus multilocularis, we have cloned and characterized the parasite''s orthologues of the key regulatory factors Ras and Raf. Using a degenerative PCR approach a gene, emras, was identified whose gene product, EmRas, showed high homology (79% identical residues) to human Ras and contained all amino acid residues which are characteristic for this subfamily of small GTPases at the corresponding positions. Recombinantly expressed EmRas bound GTP and was farnesylated, but not geranyl-geranylated, by Echinococcus lysate in an in vitro prenylation assay. Furthermore, upon expression in yeast, emras was able to functionally complement the Saccharomyces orthologue RAS2 in an invasive growth assay. In Western blot analyses using an anti-EmRas antibody, the Echinococcus factor could be detected in lysates of the larval stages metacestode and protoscolex. By immune-histochemistry, EmRas was shown to localize to the germinal layer of the metacestode and to tegumental structures of the protoscolex, particularly around the rostellum and the sucker regions. In addition, we fully characterized the gene emraf whose product, EmRaf, displayed considerable homology to mammalian Raf-kinases and orthologous factors from Drosophila and Caenorhabditis elegans. emraf was co-expressed with emras in the larval stages metacestode and protoscolex during in vitro cultivation and during an infection of the intermediate host as assessed by RT-PCR experiments. The emraf gene was composed of nine exons and eight introns and shared four highly conserved exon–intron boundaries with the human gene encoding Raf-1, suggesting that both genes derived from a common evolutionary ancestor. Southern blot hybridizations demonstrated that emraf is a single copy gene. Using the yeast two-hybrid system, EmRaf was shown to interact with EmRas, but not with EmRal, a previously characterized orthologue of mammalian Ral GTPases. This is the first characterization of a Ras orthologue from a cestode and the first report on a Raf-like kinase from a platyhelminth. The data presented herein will form a solid basis for further investigations on Echinococcus signaling systems that are involved in growth control and development of the parasite. [Copyright &y& Elsevier]

Summary: Salivary epidermal growth factor (EGF) effect on oral cancer biology is unknown. We examined changes in minute volumes of whole resting and stimulated saliva, EGF concentration and its output (ELISA) in whole resting and stimulated saliva before and 2 weeks after surgical treatment in oral carcinoma patients compared to the control group. After stimulation salivary flow increased both in the control (P=0.003) and in the patients group––before (P=0.007) and after surgery (P=0.005). Higher stimulated saliva volume levels were observed before surgery than in post-treatment patients (P=0.032). A trend was seen with increasing EGF salivary concentrations after tumour excision both in resting (P=0.508) and stimulated (P=0.647) saliva. A similar ascending tendency of EGF output in stimulated saliva of post-treatment patients was observed (P=0.878). Decreased levels of EGF concentration in saliva before and its contrary tendency after surgical treatment may suggest an important role of EGF in oral cancer tumourogenesis. [Copyright &y& Elsevier]

Sorting nexins (SNXs) containing the Phox (PX) domain are implicated in the regulation of membrane trafficking and sorting processes of epithelial growth factor receptor (EGFR). In this study, we investigated whether SNX16 regulates EGF-induced cell signaling by regulating EGFR trafficking. SNX16 is localized in early and recycling endosomes via its PX domain. Mutation of the PX domain disrupted the association between SNX16 and phosphatidylinositol 3-phosphate [PtdIns(3)P]. Treatment with wortmannin, a PtdIns 3-kinase inhibitor, abolished the endosomal localization of SNX16, suggesting that the intracellular localization of SNX16 is regulated by PtdIns 3-kinase activity. SNX16 was found to associate with EGFR i after stimulation with EGF in COS-7 cells. Moreover, overexpression of SNX16 increased the rate of EGF-induced EGFR degradation and inhibited the EGF-induced up-regulation of ERK and serum response element (SRE). In addition, mutation in the PX domain significantly blocked the inhibitory effect of SNX16 on EGF-induced activation of ERK and SRE. From these results, we suggest that SNX16 directs the sorting of EGFR to the endosomal compartment and thus regulates EGF-induced cell signaling. [ABSTRACT FROM AUTHOR]

Recent studies indicate that endocytic organelles can play a more active role in signal propagation and amplification than was recognised before. By deciphering the interplay between endocytosis and signalling, we will be able to gain a more sophisticated level of understanding of signal transduction mechanisms. [Copyright &y& Elsevier]

The effects of growth factors on cartilaginous tissues are well documented. An exception is the temporomandibular joint (TMJ) disc, where data for growth factor effects on proliferation and biosynthesis are very limited. The purpose of this study was to quantify proliferation of and synthesis by TMJ disc cells cultured in monolayer with either platelet derived growth factor-AB (PDGF), basic fibroblast growth factor (bFGF) or insulin-like growth factor-I (IGF), at either a low (10 ng/ml) or high (100 ng/ml) concentration. Proliferation was assessed with a DNA quantitation technique, collagen synthesis was measured via a hydroxyproline assay, and GAG synthesis was determined with a dimethylmethylene blue dye binding assay at 14 days. Overall, the most beneficial growth factor was bFGF, which was most potent in increasing proliferation and GAG synthesis, and also effective in promoting collagen synthesis. At the high concentration, bFGF resulted in 96% more cells than the control and 30 to 45% more cells than PDGF and IGF. PDGF and bFGF were the most potent upregulators of GAG synthesis, producing 2–3 times more GAG than the control. IGF had no significant effect on GAG production, although at its higher concentration it increased collagen production by 4.5 times over the control. Collagen synthesis was promoted by bFGF at its lower concentration, with levels 4.2 times higher than the control, whereas PDGF had no significant effect on collagen production. In general, higher concentrations increased proliferation, whereas lower concentrations favoured biosynthesis. [Copyright &y& Elsevier]

The superfamily of G-protein-coupled receptors (GPCRs) could be subclassified into 7 families (A, B, large N-terminal family B-7 transmembrane helix, C, Frizzled/Smoothened, taste 2, and vomeronasal 1 receptors) among mammalian species. Cloning and functional studies of GPCRs have revealed that the superfamily of GPCRs comprises receptors for chemically diverse native ligands including (1) endogenous compounds like amines, peptides, and Wnt proteins (i.e., secreted proteins activating Frizzled receptors); (2) endogenous cell surface adhesion molecules; and (3) photons and exogenous compounds like odorants. The combined use of site-directed mutagenesis and molecular modeling approaches have provided detailed insight into molecular mechanisms of ligand binding, receptor folding, receptor activation, G-protein coupling, and regulation of GPCRs. The vast majority of family A, B, C, vomeronasal 1, and taste 2 receptors are able to transduce signals into cells through G-protein coupling. However, G-protein-independent signaling mechanisms have also been reported for many GPCRs. Specific interaction motifs in the intracellular parts of these receptors allow them to interact with scaffold proteins. Protein engineering techniques have provided information on molecular mechanisms of GPCR-accessory protein, GPCR-GPCR, and GPCR-scaffold protein interactions. Site-directed mutagenesis and molecular dynamics simulations have revealed that the inactive state conformations are stabilized by specific interhelical and intrahelical salt bridge interactions and hydrophobic-type interactions. Constitutively activating mutations or agonist binding disrupts such constraining interactions leading to receptor conformations that associates with and activate G-proteins. [Copyright &y& Elsevier]

We have recently identified and cloned the human LRIG1 gene (formerly LIG1). LRIG1 is a predicted integral membrane protein with a domain organization reminiscent of the Drosophila epidermal growth factor (EGF)-receptor antagonist Kekkon-1. We have searched for additional members of the human LRIG family and identified LRIG2 (). The LRIG2 gene was localized to chromosome 1p13 and had an open reading frame of 1065 amino acids. The LRIG2 protein was predicted to have the same domain organization as LRIG1 with a signal peptide, an extracellular part containing15 leucine-rich repeats and three immunoglobulin-like domains, a transmembrane domain, and a cytoplasmic tail. The LRIG2 amino acid sequence was 47% identical to human LRIG1 and mouse Lrig1 (also known as Lig-1). Northern blotting and RT-PCR revealed LRIG2 transcripts in all tissues analyzed. Quantitative real-time RT-PCR showed the most prominent RNA expression in skin, uterus, ovary, kidney, brain, small intestine, adrenal gland, and stomach. Immunoblotting of COS-7 cell lysates demonstrated that heterologously expressed human LRIG2 had an apparent molecular weight of 132 kDa under reducing gel-running conditions. N-glycosidase F treatment resulted in a reduction of the apparent molecular weight to 107 kDa, showing that LRIG2 was a glycoprotein carrying N-linked oligosaccharides. Cell surface biotinylation experiments and confocal fluorescence laser microscopy demonstrated expression of LRIG2 both at the cell surface and in the cytoplasm. LRIG2 was detected in tissue lysates from stomach, prostate, lung, and fetal brain by immunoblotting. In conclusion, LRIG2 was found to be a glycoprotein which was encoded by a gene on human chromosome 1p13 and its mRNA was present in all tissues analyzed. [Copyright &y& Elsevier]

Accumulating data suggest that local production of 1α,25-dihydroxyvitamin D (1α,25(OH)2D) could provide an important cell growth regulatory mechanism in an autocrine fashion in prostate cells. Previously, we demonstrated a differential expression of 1α-OHase enzymatic activity among noncancerous (PZHPV-7) and cancer cells (PC-3, DU145, LNCaP), which appears to correlate with 1α-OHase m-RNA synthesis and its promoter activities. Since it is well-established that EGF regulates the proliferation of prostate cells via autocrine and paracrine loops and 1α,25(OH)2D inhibites prostate cell proliferation, we investigated if EGF also regulated 1α-OHase expression in prostate cells. We found that EGF upregulated 1α-OHase promoter activity and enzyme activity in PZ-HPV-7 and that 1α,25(OH)2D3 inhibited EGF-dependent up-regulation of 1α-OHase enzymatic activity. Moreover, the EGF-stimulated promoter activity was inhibited 70% by the MAPKK inhibitor, PD98059, suggesting that the MAPK pathway may be one pathway involved in the regulation of prostatic 1α-OHase by EGF to increase1α,25(OH)2D synthesis as a feedback regulator of cell growth. Because EGF has no effect on 1α-OHase promoter activity in LNCaP cells, we propose that the ability of EGF to stimulate 1α,25(OH)2D synthesis may be abolished or diminished in cancer cells. [Copyright &y& Elsevier]

Genistein, a component of soy, has been reported to protect against spontaneously developing prostate tumors in the transgenic adenocarcinoma of mouse prostate (TRAMP) model. This is consistent with reports showing that Asians eating a diet high in soy have reduced incidence of clinically manifested prostate cancer. In order to understand the mechanism of action of genistein, we have investigated the expression of androgen and estrogen receptors, four growth factor receptors that signal via tyrosine protein kinases, and specific growth factor proteins in the dorsolateral prostates of TRAMP mice fed 250 mg genistein/kg diet, starting at 5 weeks of age. These analyses were carried out at 12 weeks, prior to the development of solid tumors, allowing us to readily investigate cell proliferation and biomarkers in premalignant tissue. Cell proliferation, AR, ER-alpha, EGFR, ErbB2, EGF, IGF-1R, IGF-1, VEGFR2, ERKs-1 and 2 proteins and TGF-alpha mRNA, but not ER-beta and VEGF, were significantly increased in prostates of TRAMP compared to C57BL/6 mice. Genistein in the diet significantly down-regulated cell proliferation, EGFR, IGF-1R, ERK-1 and ERK-2, but not AR, ER-alpha, ER-beta, ErbB2, EGF, TGF-alpha, IGF-1, VEGF and VEGFR in prostates of TRAMP mice. Serum testosterone and dihydrotestosterone concentrations were not significantly different in C57BL/6 or TRAMP male mice fed control or genistein-containing diets. The up-regulation of sex steroid receptors and multiple growth signaling pathways in TRAMP mice supports the concept of multiple dysregulation contributing to carcinogenesis. Down-regulation of the tyrosine kinase regulated proteins, EGFR and IGF-1R, and of the downstream mitogen-activated protein kinases, ERK-1 and 2, with genistein in the diet provides a possible mechanism for prostate cancer chemoprevention. [Copyright &y& Elsevier]

Chromaffin cells can restore function to the damaged nigrostriatal dopaminergic system in animal models of Parkinson''s disease. It has been reported that a protein which is released from chromaffin granules can promote the survival of dopaminergic neurones in vitro and protect them against N-methylpyridinium ion toxicity. This neurotrophic effect has been found to be mediated by astroglial cells and blocked by inhibitors of the epidermal growth factor (EGF) receptor signal transduction pathway. Here we report the identification of bovine heparin-binding EGF-like growth factor (HB-EGF) in chromaffin granules and the cloning of the respective cDNA from bovine-derived adrenal gland. Protein extracts from bovine chromaffin granules were found to promote the survival of embryonic dopaminergic neurones in culture, to the same extent as recombinant human HB-EGF. Furthermore, the neurotrophic action of the chromaffin granule extract could be abolished by antiserum to recombinant human HB-EGF. We also show that intracerebral injection of recombinant human HB-EGF protected the nigrostriatal dopaminergic system in an in vivo adult rat model of Parkinson''s disease. Intracerebral administration of this protein at the same time as a 6-hydroxydopamine lesion of the medial forebrain bundle was found to spare dopamine levels in the striatum and tyrosine hydroxylase-immunopositive neurones in the midbrain.This study has found that the main component in chromaffin granules responsible for their neurotrophic effect on dopaminergic neurones is HB-EGF. Furthermore, HB-EGF has significant protective effects on nigrostriatal dopaminergic neurones in vivo, making it a potential candidate for use in the treatment of Parkinson''s disease. [Copyright &y& Elsevier]

Growth factors and cytokines play an important role in tissue development and repair. However, it remains unknown how they act on proliferation and differentiation of periodontal ligament cells. In this study, we investigated the effects of several growth factors and cytokines on the synthesis of DNA, alkaline phosphatase (ALPase), fibronectin, and secreted protein acidic and rich in cysteine (SPARC) in human periodontal ligament (HPL) cells. Transforming growth factor-β (TGF-β) increased the synthesis of DNA, fibronectin and SPARC, whereas it decreased ALPase activity. Basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF) and tumor necrosis factor-α (TNF-α) decreased SPARC and ALPase levels, whereas these peptides increased DNA synthesis and did not affect fibronectin synthesis. Epidermal growth factor (EGF) up-regulated the synthesis of DNA and fibronectin and inhibited SPARC and ALPase levels. Interleukin-1β (IL-1β) decreased the synthesis of DNA, ALPase, fibronectin and SPARC. These findings demonstrate that TGF-β, bFGF, EGF, PDGF, TNF-α and IL-1β have characteristically different patterns of action on DNA, SPARC, fibronectin and ALPase synthesis by HPL cells. The differences in regulation of function of periodontal ligament cells by these peptides may be involved in the regeneration and repair of periodontal tissue. [Copyright &y& Elsevier]

Initial studies with angiogenesis inhibitors showed little clinical benefit. However, recently reported clinical studies in colorectal cancer have shown that bevacizumab, a vascular endothelial growth factor (VEGF) monoclonal antibody, in combination with cytotoxic therapy has positive effects on patient survival. Furthermore, the VEGF receptor kinase (VEGF-R) tyrosine kinase inhibitor, vatalanib, has also shown encouraging results in colorectal cancer, with molecular resonance imaging providing evidence that the anti-tumor efficacy was indeed the result of anti-angiogenic activity. Both of these agents are progressing in phase III trials. This proof of concept has stimulated the desire for second-generation VEGF-R inhibitors having an improved profile. Structural biology insight regarding the binding mode of protein kinase inhibitors is valuable for the design of molecules possessing superior selectivity, efficacy and tolerability. Towards this goal, we have developed a new series of VEGF-R2 kinase inhibitors, based upon an anthranilic acid amide scaffold. An X-ray crystal structure of a representative compound, AAL993 (ZK260253), in complex with the catalytic domain of diphosphorylated VEGF-R2 has revealed that this molecule binds to an inactive conformation of the protein. This binding mode, similar to that observed for the anti-leukemia drug, imatinib in complex with c-Abl kinase, may be responsible for the high selectivity of AAL993 and provides valuable insight for the design of further compounds. [Copyright &y& Elsevier]

The pathogenesis of allergic asthma involves the interplay of inflammatory cells and airway-resident cells, and of their secreted mediators including cytokines, chemokines, growth factors and inflammatory mediators. Receptor tyrosine kinases are important for the pathogenesis of airway remodeling. Activation of epidermal growth factor (EGF) receptor kinase and platelet-derived growth factor (PDGF) receptor kinase leads to hyperplasia of airway smooth muscle cells, epithelial cells and goblet cells. Stimulation of non-receptor tyrosine kinases (e.g. Lyn, Lck, Syk, ZAP-70, Fyn, Btk, Itk) is the earliest detectable signaling response upon antigen-induced immunoreceptor activation in inflammatory cells. Cytokine receptor dimerization upon ligand stimulation induces activation of Janus tyrosine kinases (JAKs), leading to recruitment and phosphorylation of signal transducer and activator of transcription (STAT) for selective gene expression regulation. Activation of chemokine receptors can trigger JAK–STAT pathway, Lck, Fyn, Lyn, Fgr, and Syk/Zap-70 to induce chemotaxis of inflammatory cells. Inhibitors of tyrosine kinases have been shown in vitro to block growth factor-induced hyperplasia of airway-resident cells; antigen-induced inflammatory cell activation and cytokine synthesis; cytokine-mediated pro-inflammatory gene expression in inflammatory and airway cells; and chemokine-induced chemotaxis of inflammatory cells. Recently, anti-inflammatory effects of tyrosine kinase inhibitors (e.g. genistein, tyrphostin AG213, piceatannol, tyrphostin AG490, WHI-P97, WHI-P131, Syk antisense) in animal models of allergic asthma have been reported. Therefore, development of inhibitors of tyrosine kinases can be a very attractive strategy for the treatment of asthma. [Copyright &y& Elsevier]

Protein phosphorylation and dephosphorylation play a major role in intracellular signal transduction activated by extracellular stimuli. Protein kinase B (PKB/Akt) is a central player in the signal transduction pathways activated in response to growth factors or insulin and is thought to contribute to several cellular functions including nutrient metabolism, cell growth and apoptosis. Recently, several significant publications have described novel mechanisms used to regulate PKB. Since the alteration of PKB activity is associated with several human diseases, including cancer and diabetes, understanding PKB regulation is an important task if we are to develop successful therapeutics. [Copyright &y& Elsevier]

To study the effect of growth factors on iatrogenic apoptosis, we examined the influence of vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) on staurosporine-induced apoptosis in primary cultures of human umbilical vein endothelial cells (HUVEC). Apoptosis was evaluated by a cell viability test, the TUNEL-POD assay and the activation of the pro-apoptotic caspase-3. Staurosporine (10–100 nM) caused the activation of caspase-3. This effect was manifest after 2 hr of incubation and reached its maximum after 5 hr. Severe loss of viability followed within 18 hr. VEGF or EGF (10–100 ng/mL) added together with staurosporine decreased the activation of caspase-3. The loss of viability was 24 hr delayed. The action of growth factors was observed at 1% serum concentration but also at concentration optimal for HUVEC survival (10%, v/v). Furthermore, the inhibition of PI-3 kinase (PI-3K) by wortmannin or LY294002 as well as the inhibition of MEK by PD098059 or U0126 prevented the protective effect of VEGF and EGF. Western blotting analysis showed that after 3 hr of incubation with staurosporine the level of the anti-apoptotic protein Mcl-1 decreased and this effect was reverted by VEGF. It is concluded that VEGF and EGF antagonize the pro-apoptotic action of staurosporine by the combined signalling of PI-3K and ERKs pathways. [Copyright &y& Elsevier]

Transforming growth factor-beta (TGF-β) induces apoptosis in fetal rat hepatocytes. However, a subpopulation of these cells survives concomitant with changes in morphology and phenotype, reminiscent of an epithelial mesenchymal transition (EMT) [Exp. Cell Res. 252 (1999) 281–291]. In this work, we have isolated the subpopulation that survives to TGF-β-induced apoptosis, showing that these cells maintain the response to TGF-β in terms of Smads activation and growth inhibition. Analyses of the intracellular signals that could impair the apoptotic effects of TGF-β have indicated that the phosphatidylinositol 3-kinase (PI 3-K)/Akt pathway is activated in these resistant cells. Experiments in fetal rat hepatocytes have shown that TGF-β is able to transiently activate PI 3-K/Akt by a mechanism independent of protein synthesis but dependent on a tyrosine kinase activity. Pro-apoptotic signals, such as oxidative stress and caspases, contribute to the loss of Akt at later times. Inhibiting PI 3-K sensitizes fetal hepatocytes (FH) to the apoptosis induced by TGF-β and causes spontaneous death in the resistant cells. In conclusion, TGF-β, as it is known for other cytokines, could be inducing pro-apoptotic and survival signals in hepatocytes, the balance among them will decide cell fate. [Copyright &y& Elsevier]

Objectives: Growth signaling is instrumental in tumor development. Insight into signaling pathways by molecular and cellular biology has changed the development of new anticancer agents. Outside the field of urology specifically targeted drugs such as imatinib mesylate and gefitinib showed impressive anticancer activity in chronic myeloid leukemia and non-small cell lung cancer, respectively.Methods: Literature search of PubMed documented publications and abstracts from meetings.Results: Preclinical data in prostate cancer shows upregulation of a wide variety of growth factors and their receptors such as PDGF, EGF, IGF, FGF, and VEGF suggesting efficacy of agents targeting these pathways. Here the preclinical evidence and first clinical data on the use of growth signal targeting in prostate cancer is reviewed. Although some anticancer efficacy of signal transduction inhibition monotherapy was reported, combination with chemotherapy and radiotherapy seemed most promising in prostate cancer.Conclusion: So-called smart drugs are small molecules targeted at specific growth signaling pathways. These new drugs will dominate clinical trials in the years to come either as single-drug modality, but more likely as combination treatment. [Copyright &y& Elsevier]

Sprouty2 plays a key role in negatively modulating the fibroblast growth factor signaling pathway, which is required for early branching events in embryonic development. The expression of the murine Sprouty2 gene shows a temporally and spatially restricted pattern in developing lung. In order to clarify the molecular mechanisms governing the transcription of the Sprouty2 gene, we first characterized the genomic organization of the human Sprouty2 (hSpry2) gene and mapped its transcription start sites by 5′-rapid amplification of cDNA ends. Subsequently, a 4-kb sequence from the 5′-flanking region of the gene was cloned and determined to contain promoter activity. Detailed truncation analysis of the hSpry2 promoter revealed the presence of context-specific suppressor activity in the distal upstream region. More importantly, we demonstrated that all the elements necessary to achieve strong basal transcription activity were located within the proximal 0.4-kb region. Sequence analysis revealed that this functionally important proximal region contains neither TATA nor CAAT box but an initiator element around the transcription start site. Several cis-acting elements (including AP2, CREB, SP1 and Ets-1) were found to be present in the proximal region, and their interactions with specific nuclear proteins were confirmed by electrophoretic mobility shift assays. To our knowledge, this is the first promoter study of any mammalian Sprouty gene. We propose that the high-level basal expression of hSpry2 is controlled by multiple transcription factors binding to its proximal promoter. [Copyright &y& Elsevier]

The developing fetal and neonatal gastrointestinal (GI) tract is influenced by many growth factors, including epidermal growth factor (EGF), insulin-like growth factor (IGF), transforming growth factor (TGF), and erythropoietin (Epo). Granulocyte colony-stimulating factor (G-CSF), typically regarded as a hematopoietic growth factor, might also be included because it exists in high concentrations in amniotic fluid, colostrum, and human milk, and because granulocyte CSF receptors (G-CSF-R) are abundantly expressed on the villous enterocytes of the developing intestine. As a first step toward understanding whether the effects of G-CSF on the GI tract were local or systemic, we sought to determine whether recombinant human G-CSF (rhG-CSF) administered enterally to suckling mice, is absorbed into the circulation, and if so, whether the G-CSF-R is essential for this absorption. We enterally administered rhG-CSF to suckling mice, selecting a daily dose based on the amount of G-CSF normally swallowed by the fetus and neonate (3 ng), or in other mice, a dose of G-CSF 100 times larger (300 ng). Pups were tested at either 5–7 days of age, or at 14–16 days of age. C57BL/6×129SvJ mice were used. Some mice had a targeted null mutation in the G-CSF-R gene, producing a non-functional G-CSF-R protein. At intervals following the enteral G-CSF dosing, G-CSF concentrations in plasma were measured by specific ELISA. The bioavailability of G-CSF was invariably <1%, regardless of the dose of rhG-CSF given, the age of the pups, or whether they had a functional G-CSF-R. After enteral administration of rhG-CSF to suckling mice, only minimal quantities of G-CSF are absorbed into the circulation, and the G-CSF-R is not essential for this absorption. [Copyright &y& Elsevier]

Tissue engineering aims to replace damaged tissues or organs using either transplanted cells or host cells recruited to the target site. Protein signaling is crucial to regulate cell phenotype and thus engineered tissue structure and function. Biomaterial vehicles are being designed to incorporate and locally deliver various molecules involved in this signaling, including both growth factors and peptides that mimick whole proteins. Controlling the concentration, local duration and spatial distribution of these factors is key to their utility and efficacy. Recent advances have been made in the development of polymeric delivery systems intended to achieve this control. [Copyright &y& Elsevier]

Extracellular transport processes play critical roles in morphogenesis. While diffusive transport effects on morphogenesis are well illustrated in examples like blood capillary architecture and in cell morphogenetic responses to the local extracellular protein environment, the effects of fluid convection, although important in many developing and regenerating tissues, are not well understood. Convective forces are present whenever a hydrated tissue undergoes dynamic mechanical strain, and so convection could not only dominate the transport of large molecules like proteins, but might also serve as a mechanism for mechanosensing. The complex interdependence of mechanical forces, protein transport and extracellular morphogen gradients needs to be elucidated in a comprehensive way in order for the importance of transport on morphogenesis to be fully appreciated. [Copyright &y& Elsevier]

ADAMs contain adhesive and metalloprotease domains. As major ectodomain sheddases, they release a variety of cell-surface proteins, including growth factors, cytokines, cell adhesion molecules and receptors. ADAMs can also cleave and remodel components of the extracellular matrix. Hence, ADAMs are emerging as key modulators of cell–cell and cell–matrix interactions. Important questions, including if and how ADAM adhesive domains promote ADAM protease function, are currently being addressed. [Copyright &y& Elsevier]

Adhesion molecules, although catalytically inactive, are able to translate environmental cues into complex intracellular signals. They can do this by associating with tyrosine kinase receptors for growth factors, which can prime, integrate or feedback adhesion-based signals. Recent results show that reciprocal crosstalk between the two systems is only one facet of such a collaboration, and that unconventional and alternative hierarchies can be established in which, on the one hand, cell adhesion can trigger ligand-independent activation of growth factor receptors, and, on the other, growth factors can induce adhesion molecules to propagate adhesion-independent signals. [Copyright &y& Elsevier]

Chemotaxis is an important mechanism controlling cell migration over either short or long distances during different developmental processes. Small rapid diffusing chemo-attractants are detected through serpentine, G protein coupled receptors through graded activation of receptors along the length of the cell. Internal amplification results in polarisation of the actin and myosin cytoskeletal dynamics along the gradient and directed movement. The dynamics of these processes can now be studied in individual cells in developing organisms. Slow diffusing chemo-attractants such as growth factors, providing short-range guidance information, often signal through tyrosine kinase receptors. Detection of these signals may involve the active extension of very long cellular process up growth factor gradients, followed by translocation of the cell in the direction of the gradient. [Copyright &y& Elsevier]

Insulin-like growth factor 1 receptor (IGF-1R) plays an important role in cell growth and malignant transformation. To investigate IGF-1R-dependent signaling events and its effects on apoptosis induction and cellular proliferation, we generated a constitutively active, ligand-independent IGF-1R variant. We fused the cytoplasmic domain of the IGF-1R to the extracellular and transmembrane domains of the oncogenic ErbB2 receptor (ErbB2V→E/IGF-1). A fusion protein in which the wild-type sequence of the ErbB2 receptor was used, served as a control (ErbB2V/IGF-1R). ErbB2V/IGF-1R, ErbB2V→E/IGF-1R and IGF-1R were stably transfected into interleukin 3 (IL-3)-dependent BaF/3 cells. ErbB2V→E/IGF-1R expressing cells exhibited ligand-independent, constitutive tyrosine phosphorylation of the receptor fusion protein. Constitutively, activated ErbB2V→E/IGF-1R conferred IL-3 independence for growth and survival to the transfected BaF/3 cells. Constitutive activation of the IGF-1R results in cellular growth and protection against apoptosis upon IL-3 withdrawal in BaF/3 cells. [Copyright &y& Elsevier]

Summary¶ Overexpression or untimely expression of wild-type or mutated protein growth factors and their receptors is associated with the biology of malignant gliomas and other types of cancer. It may result in unchecked tumour cell proliferation, migration/invasion into normal tissue, tumour angiogenesis, escape from immune surveillance, and decreased apoptotic cell death, i.e. after treatment with cytotoxic agents. This often involves activation of growth factor receptors either by simultaneous production of growth factors and corresponding receptors on the same or adjacent tumour cells or by constitutive receptor activation due to mutations. In several instances, the cellular genes encoding these growth factors and receptors are homologous to transforming genes/oncogenes from tumourigenic retroviruses and have thus been regarded as cellular proto-oncogenes. In recent years much progress has been made towards a better understanding of the function of these molecules and how they lead to the aggressive phenotype of malignant gliomas and its inherent resistance to adjuvant therapies. This, still insufficient, knowledge is a prerequisite for the development of novel therapies for this non-curable disease. The aim of this review is to address relevant growth factor receptor systems with emphasis on their particular role in glioma biology. [ABSTRACT FROM AUTHOR]

Growing evidence demonstrates human milk's protective effect against necrotizing enterocolitis (NEC). Human milk derives these properties from biologically active compounds that influence intestinal growth, barrier function, microvascular development, and immunological maturation. Among these protective compounds are growth factors that are secreted into milk with relatively high concentrations during the early postnatal period, when newborns are most susceptible to NEC. This paper reviews the current knowledge on human milk growth factors and their mechanisms of action relevant to NEC prevention. It will also discuss the stability of these growth factors with human milk pasteurization and their potential for use as supplements to infant formulas with the goal of preventing NEC. [ABSTRACT FROM AUTHOR]

Development of the palate is the result of an organized series of events that require exquisite spatial and temporal regulation at the cellular level. There are a myriad of growth factors, receptors and signaling pathways that have been shown to play an important role in growth, elevation and/or fusion of the palatal shelves. Altered expression or activation of a number of these factors, receptors and signaling pathways have been shown to cause cleft palate in humans or mice with varying degrees of penetrance. This review will focus on connective tissue growth factor (CTGF) or CCN2, which was recently shown to play an essential role in formation of the secondary palate. Specifically, the absence of CCN2 in KO mice results in defective cellular processes that contribute to failure of palatal shelf growth, elevation and/or fusion. CCN2 is unique in that it has been shown to interact with a number of other factors important for palate development, including bone morphogenetic proteins (BMPs), fibroblast growth factors (FGFs), epidermal growth factor (EGF), Wnt proteins and transforming growth factor-βs (TGF-βs), thereby influencing their ability to bind to their receptors and mediate intracellular signaling. The role that these factors play in palate development and their specific interactions with CCN2 will also be reviewed. Future studies to elucidate the precise mechanisms of action for CCN2 and its interactions with other regulatory proteins during palatogenesis are expected to provide novel information with the potential for development of new pharmacologic or genetic treatment strategies for clinical intervention of cleft palate during development. [ABSTRACT FROM AUTHOR]