Periodontal treatment downregulates protease-activated receptor 2 in human gingival crevicular fluid cells

Protease-activated receptor 2 (PAR2) is implicated in the pathogenesis of chronic inflammatory diseases, including periodontitis; it can be activated by gingipain and produced by Porphyromonas gingivalis and by neutrophil protease 3 (P3). PAR2 activation plays a relevant role in inflammatory processes by inducing the release of important inflammatory mediators associated with periodontal breakdown. The effects of periodontal treatment on PAR2 expression and its association with levels of proinflammatory mediators and activating proteases were investigated in chronic periodontitis patients. Positive staining for PAR2 was observed in gingival crevicular fluid cells and was reflective of tissue destruction. Overexpression of PAR2 was positively associated with inflammatory clinical parameters and with the levels of interleukin-6 (IL-6), IL-8, tumor necrosis factor alpha, matrix metalloprotease 2 (MMP-2), MMP-8, hepatocyte growth factor, and vascular endothelial growth factor. Elevated levels of gingipain and P3 and decreased levels of dentilisin and the protease inhibitors secretory leukocyte protease inhibitor and elafin were also associated with PAR2 overexpression. Healthy periodontal sites from individuals with chronic periodontitis showed diminished expression of PAR2 mRNA and the PAR2 protein (P < 0.05). Furthermore, periodontal treatment resulted in decreased PAR2 expression and correlated with decreased expression of inflammatory mediators and activating proteases. We concluded that periodontal treatment resulted in decreased levels of proteases and that proinflammatory mediators are associated with decreased PAR2 expression, suggesting that PAR2 expression is influenced by the presence of periodontal infection and is not a constitutive characteristic favoring periodontal inflammation.

Influence of the dopaminergic system, CREB, and transcription factor-κB on cocaine neurotoxicity

Cocaine is a widely used drug and its abuse is associated with physical, psychiatric and social problems. Abnormalities in newborns have been demonstrated to be due to the toxic effects of cocaine during fetal development. The mechanism by which cocaine causes neurological damage is complex and involves interactions of the drug with several neurotransmitter systems, such as the increase of extracellular levels of dopamine and free radicals, and modulation of transcription factors. The aim of this review was to evaluate the importance of the dopaminergic system and the participation of inflammatory signaling in cocaine neurotoxicity. Our study showed that cocaine activates the transcription factors NF-κB and CREB, which regulate genes involved in cellular death. GBR 12909 (an inhibitor of dopamine reuptake), lidocaine (a local anesthetic), and dopamine did not activate NF-κB in the same way as cocaine. However, the attenuation of NF-κB activity after the pretreatment of the cells with SCH 23390, a D1 receptor antagonist, suggests that the activation of NF-κB by cocaine is, at least partially, due to activation of D1 receptors. NF-κB seems to have a protective role in these cells because its inhibition increased cellular death caused by cocaine. The increase in BDNF (brain-derived neurotrophic factor) mRNA can also be related to the protective role of both CREB and NF-κB transcription factors. An understanding of the mechanisms by which cocaine induces cell death in the brain will contribute to the development of new therapies for drug abusers, which can help to slow down the progress of degenerative processes.

Strong iron demand during hypoxia-induced erythropoiesis is associated with down-regulation of iron-related proteins and myoglobin in human skeletal muscle

[EN] Iron is essential for oxygen transport because it is incorporated in the heme of the oxygen-binding proteins hemoglobin and myoglobin. An interaction between iron homeostasis and oxygen regulation is further suggested during hypoxia, in which hemoglobin and myoglobin syntheses have been reported to increase. This study gives new insights into the changes in iron content and iron-oxygen interactions during enhanced erythropoiesis by simultaneously analyzing blood and muscle samples in humans exposed to 7 to 9 days of high altitude hypoxia (HA). HA up-regulates iron acquisition by erythroid cells, mobilizes body iron, and increases hemoglobin concentration. However, contrary to our hypothesis that muscle iron proteins and myoglobin would also be up-regulated during HA, this study shows that HA lowers myoglobin expression by 35% and down-regulates iron-related proteins in skeletal muscle, as evidenced by decreases in L-ferritin (43%), transferrin receptor (TfR; 50%), and total iron content (37%). This parallel decrease in L-ferritin and TfR in HA occurs independently of increased hypoxia-inducible factor 1 (HIF-1) mRNA levels and unchanged binding activity of iron regulatory proteins, but concurrently with increased ferroportin mRNA levels, suggesting enhanced iron export. Thus, in HA, the elevated iron requirement associated with enhanced erythropoiesis presumably elicits iron mobilization and myoglobin down-modulation, suggesting an altered muscle oxygen homeostasis.

Regulación de la proliferación tumoral y la apoptosis en tumores epidermoides de cavidad oral: papel del receptor para el factor de crecimiento insulínico tipo 1 (IGF-1R) y major vault proteína (MVP)

Programa de doctorado: Cáncer: Biología y Clínica

Modulation of epidermial growth factor receptor signaling in colon adenocarcinoma

The use of agents targeting EGFR represents a new frontier in colon cancer therapy. Among these, monoclonal antibodies (mAbs) and EGFR tyrosine kinase inhibitors (TKIs) seemed to be the most promising. However they have demonstrated low utility in therapy, the former being effective at toxic doses, the latter resulting inefficient in colon cancer. This thesis work presents studies on a new EGFR inhibitor, FR18, a molecule containing the same naphtoquinone core as shikonin, an agent with great anti-tumor potential. In HT-29, a human colon carcinoma cell line, flow cytometry, immunoprecipitation, and Western blot analysis, confocal spectral microscopy have demonstrated that FR18 is active at concentrations as low as 10 nM, inhibits EGF binding to EGFR while leaving unperturbed the receptor kinase activity. At concentration ranging from 30 nM to 5 μM, it activates apoptosis. FR18 seems therefore to have possible therapeutic applications in colon cancer. In addition, surface plasmon resonance (SPR) investigation of the direct EGF/EGFR complex interaction using different experimental approaches is presented. A commercially available purified EGFR was immobilised by amine coupling chemistry on SPR sensor chip and its interaction to EGF resulted to have a KD = 368 ± 0.65 nM. SPR technology allows the study of biomolecular interactions in real-time and label-free with a high degree of sensitivity and specificity and thus represents an important tool for drug discovery studies. On the other hand EGF/EGFR complex interaction represents a challenging but important system that can lead to significant general knowledge about receptor-ligand interactions, and the design of new drugs intended to interfere with EGFR binding activity.

La molecola IRTA1 (immunoglobulin superfamily receptor trans location associated 1) risulta selettivamente espressa nei linfomi non Hodgkin B della zona marginale

La diagnosi di linfoma non Hodgkin B della zona marginale si basa su criteri morfologici e sulla sostanziale negatività per marcatori immunoistochimici espressi in altri sottotipi di linfoma B. L’ obiettivo di questo lavoro è stato, quindi, quello di ricercare una molecola specifica associata ai linfomi della zona marginale. Materiali e Metodi. Sono stati esaminati 2.104 linfomi periferici di entità nosologia eterogenea mediante un anticorpo monoclonale, diretto contro la molecola IRTA1, che riconosce la zona marginale nei tessuti linfoidi umani. Risultati. Si è riscontrata espressione di IRTA1 nel 93% dei linfomi della zona marginale ad insorgenza extranodale e nel 74% di quelli primitivi linfonodali suggerendo la possibilità che questi linfomi possano originare dalle cellule perifollicolari o monocitoidi IRTA1+ riscontrabili nei linfonodi reattivi. La valutazione immunoistochimica mediante doppia colorazione (IRTA1/bcl6), ha inoltre dimostrato come vi sia una modulazione fenotipica nelle cellule marginali neoplastiche nel momento in cui esse colonizzano i follicoli linfoidi e durante la loro circolazione nei centri germinativi. Le cellule marginali neoplastiche che differenziano in senso plasmacellulare perdono l’ espressione di IRTA1 Discussione. In conclusione, tali evidenze hanno permesso di ampliare la conoscenza sulla biologia dei linfomi marginali e sottolineano come IRTA1 sia il primo marcatore diagnostico positivo per queste neoplasie.

Airway Basal Cell Vascular Endothelial Growth Factor-mediated Cross-Talk Regulates Endothelial Cell Dependent Growth Support of Human Airway Basal Cells

The human airway epithelium is a pseudostratified heterogenous layer comprised of cili-ated, secretory, intermediate and basal cells. As the stem/progenitor population of the airway epi-thelium, airway basal cells differentiate into ciliated and secretory cells to replenish the airway epithelium during physiological turnover and repair. Transcriptome analysis of airway basal cells revealed high expression of vascular endothelial growth factor A (VEGFA), a gene not typically associated with the function of this cell type. Using cultures of primary human airway basal cells, we demonstrate that basal cells express all of the 3 major isoforms of VEGFA (121, 165 and 189) but lack functional expression of the classical VEGFA receptors VEGFR1 and VEGFR2. The VEGFA is actively secreted by basal cells and while it appears to have no direct autocrine function on basal cell growth and proliferation, it functions in a paracrine manner to activate MAPK signaling cascades in endothelium via VEGFR2 dependent signaling pathways. Using a cytokine- and serum-free co-culture system of primary human airway basal cells and human endothelial cells revealed that basal cell secreted VEGFA activated endothelium to ex-press mediators that, in turn, stimulate and support basal cell proliferation and growth. These data demonstrate novel VEGFA mediated cross-talk between airway basal cells and endothe-lium, the purpose of which is to modulate endothelial activation and in turn stimulate and sustain basal cell growth.

Insulin-like growth factor-I treatment in primary growth hormone insensitivity: effect of recombinant human IGF-I (rhIGF-I) and rhIGF-I/rhIGF-binding protein-3 complex

Growth hormone insensitivity syndrome (GHIS) is a rare cause of growth retardation characterized by high serum GH levels, and low serum insulin-like growth factor I (IGF-I) levels associated with a genetic defect of the GH receptor (GHR) as well post-GHR signaling pathway. Based on clinical, as well as biochemical characteristics, GHIS can be genetically classified as classical/Laron's syndrome and nonclassical/atypical GHIS. Recombinant human IGF-I (rhIGF-I) treatment is effective in promoting growth in subjects who have GHIS. Further, pharmacological studies of a IGF-I compound containing a 1:1 molar complex of rhIGF-I and rhIGF-binding protein-3 (BP-3) demonstrated that the complex was effective in increasing levels of circulating total and free IGF-I and that the administration in patients with GHIS should be safe, well-tolerated and more effective than rhIGF-I on its own.

Anti insulin-like growth factor I receptor immunoliposomes: a single formulation combining two anticancer treatments with enhanced therapeutic efficiency

Context: Through overexpression and aberrant activation in many human tumors, the IGF system plays a key role in tumor development and tumor cell proliferation. Different strategies targeting IGF-I receptor (IGFI-R) have been developed, and recent studies demonstrated that combined treatments with cytostatic drugs enhance the potency of anti-IGFI-R therapies. Objective: The objective of the study was to examine the IGFI-R expression status in neuroendocrine tumors of the gastroenteropancreatic system (GEP-NETs) in comparison with healthy tissues and use potential overexpression as a target for novel anti-IGFI-R immunoliposomes. Experimental Design: A human tumor tissue array and samples from different normal tissues were investigated by immunohistochemistry. An IGFI-R antagonistic antibody (1H7) was coupled to the surface of sterically stabilized liposomes loaded with doxorubicin. Cell lines from different tumor entities were investigated for liposomal association studies in vitro. For in vivo experiments, neuroendocrine tumor xenografts were used for evaluation of pharmacokinetic and therapeutic properties of the novel compound. Results: Immunohistochemistry revealed significant IGFI-R overexpression in all investigated GEP-NETs (n = 59; staining index, 229.1 +/- 3.1%) in comparison with normal tissues (115.7 +/- 3.7%). Furthermore, anti-IGFI-R immunoliposomes displayed specific tumor cell association (44.2 +/- 1.6% vs. IgG liposomes, 0.8 +/- 0.3%; P < 0.0001) and internalization in human neuroendocrine tumor cells in vitro and superior antitumor efficacy in vivo (life span 31.5 +/- 2.2 d vs. untreated control, 19 +/- 0.6, P = 0.008). Conclusion: IGFI-R overexpression seems to be a common characteristic of otherwise heterogenous NETs. Novel anti-IGFI-R immunoliposomes have been developed and successfully tested in a preclinical model for human GEP-NETs. Moreover in vitro experiments indicate that usage of this agent could also present a promising approach for other tumor entities.

Biology of FGFRL1, the fifth fibroblast growth factor receptor

FGFRL1 (fibroblast growth factor receptor like 1) is the most recently discovered member of the FGFR family. It contains three extracellular Ig-like domains similar to the classical FGFRs, but it lacks the protein tyrosine kinase domain and instead contains a short intracellular tail with a peculiar histidine-rich motif. The gene for FGFRL1 is found in all metazoans from sea anemone to mammals. FGFRL1 binds to FGF ligands and heparin with high affinity. It exerts a negative effect on cell proliferation, but a positive effect on cell differentiation. Mice with a targeted deletion of the Fgfrl1 gene die perinatally due to alterations in their diaphragm. These mice also show bilateral kidney agenesis, suggesting an essential role for Fgfrl1 in kidney development. A human patient with a frameshift mutation exhibits craniosynostosis, arguing for an additional role of FGFRL1 during bone formation. FGFRL1 contributes to the complexity of the FGF signaling system.

Antiproliferative effects of antiestrogens and inhibitors of growth factor receptor signaling on endometrial cancer cells

In patients with advanced estrogen-dependent type I endometrial cancer (EC), pharmacological treatment with progestins or antiestrogens is recommended, but primary and secondary resistance are common. The aim of our study was to investigate single-agent and dual-agent therapeutic strategies in estrogen receptor-positive human EC cells.

Role of Toll interleukin-1 receptor (IL-1R) 8, a negative regulator of IL-1R/Toll-like receptor signaling, in resistance to acute Pseudomonas aeruginosa lung infection

Toll interleukin-1 receptor (IL-1R) 8 (TIR8), also known as single Ig IL-1 receptor (IL-R)-related molecule, or SIGIRR, is a member of the IL-1R-like family, primarily expressed by epithelial cells. Current evidence suggests that TIR8 plays a nonredundant role as a negative regulator in vivo under different inflammatory conditions that are dependent on IL-R and Toll-like receptor (TLR) activation. In the present study, we examined the role of TIR8 in innate resistance to acute lung infections caused by Pseudomonas aeruginosa, a Gram-negative pathogen responsible for life-threatening infections in immunocompromised individuals and cystic fibrosis patients. We show that Tir8 deficiency in mice was associated with increased susceptibility to acute P. aeruginosa infection, in terms of mortality and bacterial load, and to exacerbated local and systemic production of proinflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], IL-1β, and IL-6) and chemokines (CXCL1, CXCL2, and CCL2). It has been reported that host defense against P. aeruginosa acute lung infection can be improved by blocking IL-1 since exaggerated IL-1β production may be harmful for the host in this infection. In agreement with these data, IL-1RI deficiency rescues the phenotype observed in Tir8-deficient mice: in Tir8-/- IL-1RI-/- double knockout mice we observed higher survival rates, enhanced bacterial clearance, and reduced levels of local and systemic cytokine and chemokine levels than in Tir8-deficient mice. These results suggest that TIR8 has a nonredundant effect in modulating the inflammation caused by P. aeruginosa, in particular, by negatively regulating IL-1RI signaling, which plays a major role in the pathogenesis of this infectious disease.

Human epidermal growth factor receptor-2 gene amplification in gastric cancer using tissue microarray technology

To assess human epidermal growth factor receptor-2 (HER2)-status in gastric cancer and matched lymph node metastases by immunohistochemistry (IHC) and chromogenic in situ hybridization (CISH).