Interleukin 33 supports squamous cell carcinoma growth via a dual effect on tumour proliferation, migration and invasion, and T cell activation.

Interleukin (IL)-33 is an important cytokine in the tumour microenvironment; it is known to promote the growth and metastasis of solid cancers, such as gastric, colorectal, ovarian and breast cancer. Our group demonstrated that the IL-33/ST2 pathway enhances the development of squamous cell carcinoma (SCC). Conversely, other researchers have reported that IL-33 inhibits tumour progression. In addition, the crosstalk between IL-33, cancer cells and immune cells in SCC remains unknown. The aim of this study was to investigate the effect of IL-33 on the biology of head and neck SCC lines and to evaluate the impact of IL-33 neutralisation on the T cell response in a preclinical model of SCC. First, we identified epithelial and peritumoural cells as a major local source of IL-33 in human SCC samples. Next, in vitro experiments demonstrated that the addition of IL-33 significantly increased the proliferative index, motility and invasiveness of SCC-25 cells, and downregulated MYC gene expression in SCC cell lines. Finally, IL-33 blockade significantly delayed SCC growth and led to a marked decrease in the severity of skin lesions. Importantly, anti-IL-33 monoclonal antibody therapy increase the percentage of CD4+IFNγ+ T cells and decreased CD4+ and CD8+ T cells secreting IL-4 in tumour-draining lymph nodes. Together, these data suggest that the IL-33/ST2 pathway may be involved in the crosstalk between the tumour and immune cells by modulating the phenotype of head and neck SCC and T cell activity. IL-33 neutralisation may offer a novel therapeutic strategy for SCC.

Interleukin 33 supports squamous cell carcinoma growth via a dual effect on tumour proliferation, migration and invasion, and T cell activation

Interleukin (IL)-33 is an important cytokine in the tumour microenvironment; it is known to promote the growth and metastasis of solid cancers, such as gastric, colorectal, ovarian and breast cancer. Our group demonstrated that the IL-33/ST2 pathway enhances the development of squamous cell carcinoma (SCC). Conversely, other researchers have reported that IL-33 inhibits tumour progression. In addition, the crosstalk between IL-33, cancer cells and immune cells in SCC remains unknown. The aim of this study was to investigate the effect of IL-33 on the biology of head and neck SCC lines and to evaluate the impact of IL-33 neutralisation on the T cell response in a preclinical model of SCC. First, we identified epithelial and peritumoural cells as a major local source of IL-33 in human SCC samples. Next, in vitro experiments demonstrated that the addition of IL-33 significantly increased the proliferative index, motility and invasiveness of SCC-25 cells, and downregulated MYC gene expression in SCC cell lines. Finally, IL-33 blockade significantly delayed SCC growth and led to a marked decrease in the severity of skin lesions. Importantly, anti-IL-33 monoclonal antibody therapy increase the percentage of CD4+IFNγ+ T cells and decreased CD4+ and CD8+ T cells secreting IL-4 in tumour-draining lymph nodes. Together, these data suggest that the IL-33/ST2 pathway may be involved in the crosstalk between the tumour and immune cells by modulating the phenotype of head and neck SCC and T cell activity. IL-33 neutralisation may offer a novel therapeutic strategy for SCC.

Intranasal Flunisolide Suppresses Pathological Alterations Caused by Silica Particles in the Lungs of Mice.

Silicosis is an occupational disease triggered by the inhalation of fine particles of crystalline silica and characterized by inflammation and scarring in the form of nodular lesions in the lungs. In spite of the therapeutic arsenal currently available, there is no specific treatment for the disease. Flunisolide is a potent corticosteroid shown to be effective for controlling chronic lung inflammatory diseases. In this study, the effect of flunisolide on silica-induced lung pathological changes in mice was investigated. Swiss-Webster mice were injected intranasally with silica particles and further treated with flunisolide from day 21 to 27 post-silica challenge. Lung function was assessed by whole body invasive plethysmography. Granuloma formation was evaluated morphometrically, collagen deposition by Picrus sirius staining and quantitated by Sircol. Chemokines and cytokines were evaluated using enzyme-linked immunosorbent assay. The sensitivity of lung fibroblasts was also examined in in vitro assays. Silica challenge led to increased leukocyte numbers (mononuclear cells and neutrophils) as well as production of the chemokine KC/CXCL-1 and the cytokines TNF-α and TGF-ß in the bronchoalveolar lavage. These alterations paralleled to progressive granuloma formation, collagen deposition and impairment of lung function. Therapeutic administration of intranasal flunisolide inhibited granuloma and fibrotic responses, noted 28 days after silica challenge. The upregulation of MIP-1α/CCL-3 and MIP-2/CXCL-2 and the cytokines TNF-α and TGF-ß, as well as deposition of collagen and airway hyper-reactivity to methacholine were shown to be clearly sensitive to flunisolide, as compared to silica-challenge untreated mice. Additionally, flunisolide effectively suppressed the responses of proliferation and MCP-1/CCL-2 production from IL-13 stimulated lung fibroblasts from silica- or saline-challenged mice. In conclusion, we report that intranasal treatment with the corticosteroid flunisolide showed protective properties on pathological features triggered by silica particles in mice, suggesting that the compound may constitute a promising strategy for the treatment of silicosis.

ST2/IL-33 signaling promotes malignant development of experimental squamous cell carcinoma by decreasing NK cells cytotoxicity and modulating the intratumoral cell infiltrate.

Squamous cell carcinoma (SCC) is the second most common form of skin cancer and the mechanism(s) involved in the progression of this tumor are unknown. Increases in the expression of IL-33/ST2 axis components have been demonstrated to contribute to neoplastic transformation in several tumor models and interleukin-33 is correlated with poor prognosis of patients with squamous cell carcinoma of the tongue. Based on these observations, we sought to determine the role of the IL-33/ST2 pathway during the development of SCC. Our findings show that ST2-deficiency led to a marked decrease in the severity of skin lesions, suggesting that ST2 signaling contributed to tumor development. An analysis of tumor lesions in wild-type and ST2KO mice revealed that a lack of ST2 was associated with specific and significant reductions in the numbers of CD4+ T cells, CD8+ T cells, dendritic cells, and macrophages. In addition, NK cells that were isolated from ST2KO mice exhibited higher cytotoxic activity than cells isolated from wild-type mice. Notably, ST2 deficiency resulted in lower IFN-γ, TNF-α, IL-10, and IL-17 production in tumor samples. Our findings indicate that the IL-33/ST2 pathway contributes to the development of SCC by affecting leukocyte migration to tumor microenvironment and impairing NK cytotoxic activity.

Diabetes Downregulates Allergen-Induced Airway Inflammation in Mice.

Previous studies described that allergic diseases, including asthma, occur less often than expected in patients with type 1 diabetes. Here, we investigated the influence of diabetes on allergic airway inflammation in a model of experimental asthma in mice. Diabetes was induced by intravenous injection of alloxan into 12 h-fasted A/J mice, followed by subcutaneous sensitization with ovalbumin (OVA) and aluminum hydroxide (Al(OH)3), on days 5 and 19 after diabetes induction. Animals were intranasally challenged with OVA (25 µg), from day 24 to day 26. Alloxan-induced diabetes significantly attenuated airway inflammation as attested by the lower number of total leukocytes in the bronchoalveolar lavage fluid, mainly neutrophils and eosinophils. Suppression of eosinophil infiltration in the peribronchiolar space and generation of eosinophilotactic mediators, such as CCL-11/eotaxin, CCL-3/MIP-1α, and IL-5, were noted in the lungs of diabetic sensitized mice. In parallel, reduction of airway hyperreactivity (AHR) to methacholine, mucus production, and serum IgE levels was also noted under diabetic conditions. Our findings show that alloxan diabetes caused attenuation of lung allergic inflammatory response in A/J mice, by a mechanism possibly associated with downregulation of IgE antibody production.

Recognition of Candida albicans by gingival fibroblasts: The role of TLR2, TLR4/CD14, and MyD88.

Recent evidence indicates that nonprofessional immune cells such as epithelial cells, endothelial cells, and fibroblasts also contribute to innate immunity via secretion of cytokines. Fibroblasts are the principal type of cell found in the periodontal connective tissues and they are involved in the immune response during periodontal disease. The role of fibroblasts in the recognition of pathogens via Toll-like receptors (TLRs) has been established; however, few studies have been conducted concerning the involvement of innate immune receptors in the recognition of Candida albicans by gingival fibroblast. In the current study, we investigate the functional activity of TLR2, cluster of differentiation 14 (CD14), and myeloid differentiation primary response gene 88 (MyD88) molecules in the recognition of C. albicans by gingival fibroblast. First, we identified that gingival fibroblasts expressed TLR2, TLR3, and TLR4. Our results showed that TLR agonists had no effect on these receptors' expression by TLR2, MyD88, and CD14-deficient cells. Notably, C. albicans and a synthetic triacylated lipoprotein (Pam3CSK4) induced a remarkable increase of TLR3 expression on MyD88-deficient gingival fibroblasts. TLR4 expression levels were lower than TLR2 and TLR3 levels and remained unchanged after TLR agonist stimulation. Gingival fibroblasts presented morphological similarities; however, TLR2 deficiency on these cells leads to a lower proliferative response, whereas the deficiency on CD14 expression resulted in lower levels of type I collagen by these cells. In addition, the recognition of C. albicans by gingival fibroblasts had an effect on the secretion of cytokines and it was dependent on a specific recognition molecule. Specifically, tumor necrosis factor-α (TNF-α) production after the recognition of C. albicans was dependent on MyD88, CD14, and TLR2 molecules, whereas the production of interleukin-1ß (IL-1ß) and IL-13 was dependent on TLR2. These findings are the first to describe a role of gingival fibroblast in the recognition of C. albicans and the pathways involved in this process. An understanding of these pathways may lead to alternative treatments for patients with periodontal disease.

Therapeutic DNA vaccine reduces schistosoma mansoni-induced tissue damage through cytokine balance and decreased migration of myofibroblasts.

Helminths are known to elicit a wide range of immunomodulation characterized by dominant Th2-type immune responses. Our group previously showed that a DNA vaccine encoding the mycobacterial 65-kDa heat shock protein (DNA-hsp65) showed immunomodulatory properties. We also showed, using a helminth-tuberculosis (TB) co-infection model, that the DNA-hsp65 vaccine protected mice against TB. We next investigated the mechanistic role of the vaccine during helminth-TB co-infection. Clinically, helminth infection causes type 2 granulomas in the lung. Mice were immunized with DNA-hsp65 while they were submitted to the type 2 granuloma induction protocol by Schistosoma mansoni eggs infusion. In this work we investigated the effects of DNA-hsp65 on the pathology and immune response during the development of type 2 granuloma induced by S. mansoni eggs. Histologic analyses of lung parenchyma showed that the DNA-hsp65 vaccine protected mice against exacerbated fibrosis induced by Schistosoma eggs, and decreased the size of the granulomas. These changes were correlated with a reduction in the number of T cells specific for the egg antigens in the lung and also with modulation of Th2 cytokine expression. Taken together, our results showed that the adjuvant properties of the DNA-hsp65 vaccine regulated the immune response in this Th2 model, and resulted in a preserved lung parenchyma.

Therapeutic efficacy of Cintredekin Besudotox (IL13-PE38QQR) in murine lung fibrosis is unaffected by immunity to Pseudomonas aeruginosa exotoxin A.

BACKGROUND: We have previously explored a therapeutic strategy for specifically targeting the profibrotic activity of IL-13 during experimental pulmonary fibrosis using a fusion protein comprised of human IL-13 and a mutated form of Pseudomonas aeruginosa exotoxin A (IL13-PE) and observed that the intranasal delivery of IL13-PE reduced bleomycin-induced pulmonary fibrosis through its elimination of IL-13-responsive cells in the lung. The aim of the present study was to determine whether the presence of an immune response to P. aeruginosa and/or its exotoxin A (PE) would diminish the anti-fibrotic properties of IL13-PE. METHODOLOGY/PRINCIPAL FINDINGS: Fourteen days after P. aeruginosa infection, C57BL/6 mice were injected with bleomycin via the intratracheal route. Other groups of mice received 4 doses of saline or IL13-PE by either intranasal or intraperitoneal application, and were challenged i.t. with bleomycin 28 days later. At day 21 after bleomycin, all mice received either saline vehicle or IL13-PE by the intranasal route and histopatological analyses of whole lung samples were performed at day 28 after bleomycin. Intrapulmonary P. aeruginosa infection promoted a neutralizing IgG2A and IgA antibody response in BALF and serum. Surprisingly, histological analysis showed that a prior P. aeruginosa infection attenuated the development of bleomycin-induced pulmonary fibrosis, which was modestly further attenuated by the intranasal administration of IL13-PE. Although prior intranasal administration of IL13-PE failed to elicit an antibody response, the systemic administration of IL13-PE induced a strong neutralizing antibody response. However, the prior systemic sensitization of mice with IL13-PE did not inhibit the anti-fibrotic effect of IL13-PE in fibrotic mice. CONCLUSIONS: Thus, IL13-PE therapy in pulmonary fibrosis works regardless of the presence of a humoral immune response to Pseudomonas exotoxin A. Interestingly, a prior infection with P. aeruginosa markedly attenuated the pulmonary fibrotic response suggesting that the immune elicitation by this pathogen exerts anti-fibrotic effects.

ATLa, an aspirin-triggered lipoxin A4 synthetic analog, prevents the inflammatory and fibrotic effects of bleomycin-induced pulmonary fibrosis.

Despite an increase in the knowledge of mechanisms and mediators involved in pulmonary fibrosis, there are no successful therapeutics available. Lipoxins (LX) and their 15-epimers, aspirin-triggered LX (ATL), are endogenously produced eicosanoids with potent anti-inflammatory and proresolution effects. To date, few studies have been performed regarding their effect on pulmonary fibrosis. In the present study, using C57BL/6 mice, we report that bleomycin (BLM)-induced lung fibrosis was prevented by the concomitant treatment with an ATL synthetic analog, ATLa, which reduced inflammation and matrix deposition. ATLa inhibited BLM-induced leukocyte accumulation and alveolar collapse as evaluated by histology and morphometrical analysis. Moreover, Sirius red staining and lung hydroxyproline content showed an increased collagen deposition in mice receiving BLM alone that was decreased upon treatment with the analog. These effects resulted in benefits to pulmonary mechanics, as ATLa brought to normal levels both lung resistance and compliance. Furthermore, the analog improved mouse survival, suggesting an important role for the LX pathway in the control of disease establishment and progression. One possible mechanism by which ATLa restrained fibrosis was suggested by the finding that BLM-induced myofibroblast accumulation/differentiation in the lung parenchyma was also reduced by both simultaneous and posttreatment with the analog (alpha-actin immunohistochemistry). Interestingly, ATLa posttreatment (4 days after BLM) showed similar inhibitory effects on inflammation and matrix deposition, besides the TGF-beta level reduction in the lung, reinforcing an antifibrotic effect. In conclusion, our findings show that LX and ATL can be considered as promising therapeutic approaches to lung fibrotic diseases.

MIP-1alpha[CCL3] acting on the CCR1 receptor mediates neutrophil migration in immune inflammation via sequential release of TNF-alpha and LTB4.

In the present study, we investigated the involvement of macrophage-inflammatory protein-1alpha (MIP-1alpha)[CC chemokine ligand 3 (CCL3)], MIP-1beta[CCL4], regulated on activation, normal T expressed and secreted (RANTES)[CCL5], and CC chemokine receptors (CCRs) on neutrophil migration in murine immune inflammation. Previously, we showed that ovalbumin (OVA)-triggered neutrophil migration in immunized mice depends on the sequential release of tumor necrosis factor alpha (TNF-alpha) and leukotriene B(4)(LTB(4)). Herein, we show increased mRNA expression for MIP-1alpha[CCL3], MIP-1beta[CCL4], RANTES[CCL5], and CCR1 in peritoneal cells harvested from OVA-challenged, immunized mice, as well as MIP-1alpha[CCL3] and RANTES[CCL5] but not MIP-1beta[CCL4] proteins in the peritoneal exudates. OVA-induced neutrophil migration response was muted in immunized MIP-1alpha[CCL3](-/-) mice, but it was not inhibited by treatment with antibodies against RANTES[CCL5] or MIP-1beta[CCL4]. MIP-1alpha[CCL3] mediated neutrophil migration in immunized mice through induction of TNF-alpha and LTB(4) synthesis, as these mediators were detected in the exudates harvested from OVA-challenged immunized wild-type but not MIP-1alpha[CCL3](-/-) mice; administration of MIP-1alpha[CCL3] induced a dose-dependent neutrophil migration, which was inhibited by treatment with an anti-TNF-alpha antibody in TNF receptor 1 (p55(-/-))-deficient mice or by MK 886 (a 5-lipoxygenase inhibitor); and MIP-1alpha[CCL3] failed to induce LTB(4) production in p55(-/-) mice. MIP-1alpha[CCL3] used CCR1 to promote neutrophil recruitment, as OVA or MIP-1alpha[CCL3] failed to induce neutrophil migration in CCR1(-/-) mice, in contrast to CCR5(-/-) mice. In summary, we have demonstrated that neutrophil migration observed in this model of immune inflammation is mediated by MIP-1alpha[CCL3], which via CCR1, induces the sequential release of TNF-alpha and LTB(4). Therefore, whether a similar pathway mediates neutrophil migration in human immune-inflammatory diseases, the development of specific CCR1 antagonists might have a therapeutic potential.