A. de Paulis

Mast cells have a protumorigenic role in human thyroid cancer

In different human carcinoma types, mast cell infiltrate increases with respect to normal tissue and mast cell density correlates with a bad prognosis. To assess the role of mast cells in human thyroid cancer, we compared the density of tryptase-positive mast cells in 96 papillary thyroid carcinomas (PTCs) versus normal thyroid tissue from 14 healthy individuals. Mast cell density was higher in 95% of PTCs (n=91) than in control tissue. Mast cell infiltrate correlated with extrathyroidal extension (P=0.0005) of PTCs. We show that thyroid cancer cell-line-derived soluble factors induce mast cell activation and chemoattraction in vitro. Different mast cell lines (HMC-1 and LAD2) and primary human lung mast cells induced thyroid cancer cell invasive ability, survival and DNA synthesis in vitro. The latter effect was mainly mediated by three mast-cell-derived mediators: histamine, and chemokines CXCL1/GROα and CXCL10/IP10. We show that xenografts of thyroid carcinoma cells (8505-C) could recruit mast cells injected into the tail vein of mice. Co-injection of human mast cells accelerated the growth of thyroid cancer cell (8505-C) xenografts in athymic mice. This effect was mediated by increased tumor vascularization and proliferation, and was reverted by treating mice with sodium cromoglycate (Cromolyn), a specific mast cell inhibitor. In conclusion, our study data suggest that mast cells are recruited into thyroid carcinomas and promote proliferation, survival and invasive ability of cancer cells, thereby contributing to thyroid carcinoma growth and invasiveness.

Loratadine and desethoxylcarbonyl-loratadine inhibit the immunological release of mediators from human FceRI+cells

Background Loratadine, a novel histamine H1‐receptor antagonist, is effective in the treatment of patients with seasonal and perennial rhinitis and some allergic skin disorders. Histamine and other chemical mediators are synthesized and immunologically released by human peripheral blood basophils and tissue mast cells (FcɛRI+ cells).

Mast cells induce epithelial-to-mesenchymal transition and stem cell features in human thyroid cancer cells through an IL-8-Akt-Slug pathway.

There is increasing evidence that mast cells (MCs) and their mediators are involved in the remodeling of the tumor microenvironment and promote tumor growth, angiogenesis and metastasis. We have found that an increased density of MCs in thyroid cancer (TC) correlates with enhanced invasiveness. However, the MC-derived factors responsible for this activity and the mechanisms by which they enhance TC invasiveness remain unidentified. Here, we report that MCs, when activated by TC cells, produce soluble factors that induce epithelial-to-mesenchymal transition (EMT) and stemness features of TC cells. We identified CXCL8/interleukin (IL)-8 as the main mediator contained in activated MC conditioned media (CM) capable of inducing both EMT and stemness of TC cells. Mechanistically, MC CM or exogenous IL-8 stimulated Akt phosphorylation and Slug expression in TC cells. The inhibition of the Akt pathway or depletion of the Slug transcription factor by RNA interference, reverted EMT and stemness responses. TC cells stably transfected with exogenous IL-8 underwent EMT, displayed increased stemness and enhanced tumorigenicity with respect to control cells. The analysis of TC surgical specimens by immunohistochemical analysis demonstrated a positive correlation between MC density (Tryptase+ cells) and stemness features (OCT4 staining). Taken together, our data identify an MC-dependent IL-8–Akt–Slug pathway that sustains EMT/stemness of TC cells. The blockade of this circuit might be exploited for the therapy of advanced TC.

Physiological concentrations of zinc inhibit the release of histamine from human basophils and lung mast cells

We have previously shown that physiological concentrations of zinc (congruent to 7 X 10(-6) M) inhibit the release of histamine from human basophil leukocytes (Marone et al., J. Pharmacol. Exp. Ther. 217: 292, 1981). In these experiments we compared the effect of zinc chloride on the release of chemical mediators from human basophils and mast cells isolated from human lung. Preincubation (5 min, 37 degrees C) of human basophils and lung mast cells with zinc chloride (10(-6)-3 X 10(-5) M) caused dose-related inhibition of histamine and peptide leukotriene C4 (LTC4) release induced by anti-IgE. Increase Ca2+ concentrations (0.3 to 6 mM) in the extracellular medium completely reversed the inhibitory effect of zinc on anti-IgE-mediated histamine secretion. Zinc chloride was a competitive antagonist of the action of Ca2+ in histamine secretion induced by anti-IgE with a dissociation constant (Kd) of about 10(-5) M in both the basophil and mast cell systems. Thus physiological concentrations of zinc inhibit the release of histamine from human basophils and lung mast cells, presumably by blocking Ca2+ uptake induced by anti-IgE activation.

The formyl peptide receptor 1 exerts a tumor suppressor function in human gastric cancer by inhibiting angiogenesis

N-formyl peptide receptors (FPR1, FPR2 and FPR3) are involved in innate immunity, inflammation and cancer. FPR expression, initially described in immune cells, was later observed in non-hematopoietic cell populations and tissues. Several studies suggested a role for FPRs in the progression of various tumor histotypes, including gastric cancer (GC), for which a positive association with a specific FPR1 polymorphism has recently been described. We previously showed that FPRs are expressed on gastric epithelium and are required for wound repair and restitution of barrier integrity. Here we assess the role of FPRs in GC. We characterized the functions of FPRs in GC epithelial cells (MKN28, AGS and MKN45) cultured in vitro by assessing migration, proliferation, resistance to apoptosis and activation of the epithelial-to-mesenchymal transition. Activation of each FPR induced the epithelial-to-mesenchymal transition, proliferation, resistance to apoptosis and migration of GC cells in culture. Blocking compounds or RNA interference of each FPR reverted these effects. We also defined the in vivo tumorigenic potential of GC epithelial cells silenced for FPRs by xenograft experiments in immunocompromised mice. Interestingly, FPR1 silencing in GC cells (shFPR1) significantly enhanced xenograft growth with respect to shCTR, shFPR2 and shFPR3 xenografts, because of augmented vessel density and cell proliferation. Accordingly, HIF-1α and VEGF mRNA levels were higher in shFPR1 xenografts than in controls. Moreover, the in vitro production of proangiogenic factors in response to FPR2/3 agonists (WKYMVm, LL-37, uPA, uPAR84-95, AnxA1) or to other proinflammatory mediators (IL-1α) was higher in shFPR1 GC cells than in shCTR, shFPR2 and shFPR3 cells, suggesting that FPR1 functions as an inhibitor of CG angiogenesis. Thus, we propose that FPR1 stimulation may represent a novel therapeutic approach to counteract tumor angiogenesis.

Insulin‐like growth factor‐1 protects from vascular stenosis and accelerates re‐endothelialization in a rat model of carotid artery injury

Background: IGF‐1 is a potent mitogen for vascular smooth muscle cells, but exerts protective effects on endothelial cells that may trigger antiatherogenic mechanisms. Objectives: This study was designed to test the hypothesis that an IGF‐1 excess following arterial injury prevents neointima formation and vascular stenosis. Methods: Rats were subjected to carotid balloon injury and treated with IGF‐1 (1.2 mg kg−1 per die) or saline for 10 days. Results: In IGF‐1 treated animals, high tissue levels of eNOS, Akt and its phosphorylated form were found, confirming activation of IGF‐1‐dependent signaling pathways. IGF‐1 markedly reduced neointima formation and post‐injury arterial stenosis. IGF‐1 exerted proliferative and anti‐apoptotic effects in the media of injured carotids, but inhibited mitotic activity and induced apoptosis in the neointima. Furthermore, IGF‐1 stimulated mobilization of progenitor endothelial cells and re‐endothelialization of the injured arteries. L‐NAME administration inhibited IGF‐1 vasculoprotective effects. Conclusions: IGF‐1 attenuates post‐injury carotid stenosis by exerting differential effects in the neointima and tunica media with regard to the key components of the response to injury. The data point to a novel role of IGF‐1 as a potent vasculoprotective factor.

Human urotensin II induces tissue factor and cellular adhesion molecules expression in human coronary endothelial cells: an emerging role for urotensin II in cardiovascular disease

Summary.  Background: Human urotensin II is an 11‐aminoacid peptide with a controversial role in the human cardiovascular system. Indeed, urotensin effects on vascular reactivity and in heart failure are well documented, while its potential role in the pathophysiology of athero‐thrombosis is still unknown. This study investigates the effects of urotensin on tissue factor (TF) and VCAM‐1/ICAM‐1 expression in human coronary endothelial cells (HCAECs). Methods and results: Urotensin induced TF‐mRNA transcription as demonstrated by real time PCR and expression of TF that was functionally active as demonstrated by procoagulant activity assay. In addition, urotensin induced expression of VCAM‐1 and ICAM‐1 as demonstrated by FACS analysis. VCAM‐1 and ICAM‐1 were functionally active because they increased leukocyte adhesivity to HCAECs. Urotensin‐induced expression of TF and of VCAM‐1/ICAM‐1 was mediated through the Rho A‐activation of the transcription factor, NF‐κB, as demonstrated by EMSA. Indeed, lovastatin, an HMG‐CoA reductase inhibitor, by modulating the Rho activation, and NF‐κB inhibitors, suppressed the urotensin effects on TF and CAMs. Conclusions: Data of the present study, although in vitro, describe the close relationship existing between urotensin II and athero‐thrombosis, providing for the first time support for the view that this peptide might have not only vasoactive functions but it might be an effector molecule able to induce a pro‐atherothrombotic phenotype in cells of the coronary circulation. Although future studies are required to clarify whether these mechanisms are also important in the clinical setting, this report supports an emerging new role for urotensin II in the pathogenesis and progression of cardiovascular disease.

Differential modulation of mediator release from human basophils and mast cells by mizolastine

Background Basophils and mast cells play a major role in the pathogenesis of allergic disorders by releasing several proinflammatory mediators. Some histamine H1 receptor antagonists exert anti‐inflammatory activities by modulating mediator release from basophils and mast cells.

In vitro effects of ultraviolet A on histamine release from human basophils

Background  As long‐wave ultraviolet (UV) radiation penetrates the dermis, connective tissue cellular components and circulating blood cells can be possible targets for solar UVA. Basophils, involved in the effector phase of the inflammatory response, play a part in skin diseases such as chronic urticaria, psoriasis, atopic dermatitis, fixed drug eruption, allergic contact dermatitis, urticaria pigmentosa, systemic sclerosis and bullous pemphigoid.

Ciclosporin A Inhibits Mediator Release from Human FcεRI+ Cells by Interacting with Cyclophilin

Ciclosporin A (CsA), a natural cyclic undecapep-tide originally used to prevent human organ transplant rejection [1], has more recently proved to be effective in the treatment of such autoimmune diseases as type I diabetes [2], uveoretinitis [3], rheumatoid arthritis [4] and Crohn’s disease [5]. The mechanism of action of CsA is largely unknown. Part of the immunosuppressive effect of CsA is generally attributed to the inhibition of lymphokine mRNA transcription [6]; however, CsA appears to have multiple sites of action and could exert its effects by binding to specific cytoplasmic receptor(s). Following the purification by Handschumacher et al. [7] of cyclophilin, a cytoplasmic protein which possesses peptidyl-prolylris’-írαns-isomerase (PPIase) activity [8, 9], it was suggested that CsA binding to PPIase/cyclophilin is a critical step in the molecular mechanism of action [10]. We examined the effect of CsA and of a series of analogs (CsG, CsC, CsD and CsH), which bind with decreasing affinity to cyclophilin [11], to evaluate the involvement of this protein in the release of chemical mediators from human inflammatory cells possessing high affinity receptors for IgE (FcεRI+ cells) (i.e., basophils and mast cells). Pharmacological concentrations (8–250 nM) of CsA concentration-dependently inhibited (5–60%) the release of histamine and the de novo synthesis of peptide leukotriene C4 (LTC4) from human basophils (fig. 1) and mast cells isolated from lung parenchyma challenged with anti-IgE. When basophils were activated by the ionophore A23187, which bypasses the channel-operated influx of Ca2+ [12], CsA was more potent (93 vs. 60%) and more effective at low concentrations (IC4o = 24 vs. 100 nM). The inhibition of CsA on mediator release was extremely rapid, similar to the rate of inhibition of PPIase activity [8, 9], and was not abolished by washing the cells before anti-IgE or A23187 challenge. The direct activation of different protein kinase C isoforms induced by phorbol myristate (TPA) and bryostatin 1 [13] was unaffected by preincubation with ciclospo-rins, which suggests that CsA affects biochemical step(s) that are bypassed by direct PKC activation.