Upregulated microRNA-193a-3p is responsible for cisplatin resistance in CD44(+) gastric cancer cells.

Cisplatin is a well-known anticancer drug used to treat various cancers. However, development of cisplatin resistance has hindered the efficiency of this drug in cancer treatment. Development of chemoresistance is known to involve many signaling pathways. Recent attention has focused on microRNAs (miRNAs) as potentially important upstream regulators in the development of chemoresistance. CD44 is one of the gastric cancer stem cell markers and plays a role in regulating self-renewal, tumor initiation, metastasis and chemoresistance. The purpose of the present study was to examine the mechanism of miRNA-mediated chemoresistance to cisplatin in CD44-positive gastric cancer stem cells. We sorted gastric cancer cells according to level of CD44 expression by FACS and analyzed their miRNA expression profiles by microarray analysis. We found that miR-193a-3p was significantly upregulated in CD44(+) cells compared with CD44(-) cells. Moreover, SRSF2 of miR-193a-3p target gene was downregulated in CD44(+) cells. We studied the modulation of Bcl-X and caspase 9 mRNA splicing by SRSF2 and found that more pro-apoptotic variants of these genes were generated. We also found that downstream anti-apoptotic genes such as Bcl-2 were upregulated, whereas pro-apoptotic genes such as Bax and cytochrome C were downregulated in CD44(+) cells compared to CD44(-) cells. In addition, we found that an elevated level of miR-193a-3p triggered the development of cisplatin resistance in CD44(+) cells. Inhibition of miR-193a-3p in CD44(+) cells increased SRSF2 expression and also altered the levels of multiple apoptotic genes. Furthermore, inhibition of miR-193a-3p reduced cell viability and increased the number of apoptotic cells. Therefore, miR-193a-3p may be implicated in the development of cisplatin resistance through regulation of the mitochondrial apoptosis pathway. miR-193a-3p could be a promising target for cancer therapy in cisplatin-resistant gastric cancer.

2,3,7,8-Tetrachlorodibenzo-p-dioxin-induced MUC5AC expression: aryl hydrocarbon receptor-independent/EGFR/ERK/p38-dependent SP1-based transcription.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent environmental toxicant. Epidemiological studies have associated TCDD exposure with the development of chronic obstructive pulmonary disease, which is manifested by mucous/goblet cell hyperplasia. The purpose of this research was to elucidate the pathway/mechanisms that lead to TCDD-induced gene expression in both primary normal human bronchial epithelial cells and an immortalized cell line, HBE1, under air-liquid interface conditions. TCDD exposure induced a time-dependent elevation of MUC5AC mRNA and protein synthesis, and cytochrome p450 1A1 (CYP1A1) expression in these cells. Treatment with an aryl hydrocarbon receptor antagonist had no effect on TCDD-induced MUC5AC expression, but significantly suppressed CYP1A1 induction. However, treatments with inhibitors of signaling pathways and the expression of dominant negative mutants of epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK) and p38, but not the inhibition of c-Jun N-terminal kinase pathway, abrogated MUC5AC induction, but not that of CYP1A1. These effects also occurred at the MUC5AC promoter-reporter level using the chimeric construct for a transient transfection study. Western blot analysis confirmed the phosphorylation of activated EGFR, ERK, and p38 signaling molecules, but not the c-Jun N-terminal kinase, in cells after TCDD exposure. Specificity protein 1 (Sp1) phosphorylation also occurred in cells after TCDD exposure. Both MUC5AC expression and the promoter activity were inhibited by mithramycin A, an inhibitor specific to Sp1-based transcription. These results lead to the conclusion that TCDD induced MUC5AC expression through a noncanonical aryl hydrocarbon receptor-independent, EGFR/ERK/p38-mediated signaling pathway-mediated/Sp1-based transcriptional mechanism.

Heme oxygenase-1 and carbon monoxide: emerging therapeutic targets in inflammation and allergy.

Cumulative evidence suggests that the induction of the antioxidant/anti-inflammatory heme oxygenase (HO)-1 may play a protective role in allergic inflammation. HO-1 suppresses mast cell degranulation and cytokine synthesis. The up-regulation of the HO-1 pathway has a significant protective effect against airway inflammation, mucus hyper-secretion, and hyper-responsiveness in a model of allergic asthma. Moreover, HO-1 inhibits T cell-dependent skin inflammation and differentiation and function of antigen-presenting cells. The precise underlying mechanisms for HO-1-based protection against allergic inflammation are not yet completely understood, but appear to involve the protective effects of HO-1 by-products, such as carbon monoxide (CO), biliverdin/bilirubin and free iron. Among the HO-1 by-products, CO has been shown to mimic some protective actions of HO-1 in allergic inflammations. This article reviews the latest knowledge, recent patent and studies on the protective roles and mechanisms of HO-1/CO in inflammation and allergy.

Sclerosing hemangioma, presenting as a pneumonic pattern with mucinous adenomatous hyperplasia of the lung.

Pulmonary sclerosing hemangioma is generally considered a rare neoplasm presenting as a solitary benign nodule. During routine medical examination multiple abnormal nodular shadows were detected in the right lower lung field on chest X-ray in a 48-year-old asymptomatic woman. The patient underwent wedge resection for the pulmonary lesion. The resected lung had numerous scattered tiny nodules and small nodules congregated together, forming larger nodules. All of these lesions had typical features of sclerosing hemangioma. The authors call this unusual growth pattern of sclerosing hemangioma a 'pneumonic pattern'. Adjacent to the largest lesion, a relatively well-defined small mucinous lesion composed of mucinous tall columnar cells and basaloid squamous cells was detected. Because this lesion did not have expression of thyroid transcription factor-1, it is described as mucinous adenomatous hyperplasia.

Phosphoinositide 3-kinase delta inhibitor as a novel therapeutic agent in asthma.

Multiple signal transduction pathways are involved in airway inflammation with one of the key signalling pathways being phosphoinositide 3-kinase (PI3K). Numerous components of the PI3K pathway play an important role in the expression and activation of inflammatory mediators, inflammatory cell recruitment, immune cell function, airway remodelling and corticosteroid insensitivity in asthma. More recently studies exploring the specific roles of different PI3K catalytic subunit isoforms in asthma have been initiated. Several of these have highlighted the importance of p110delta isoform as a novel target for therapeutic intervention in asthma. In this review the biological role of PI3Ks, especially PI3Kdelta, are highlighted and the therapeutic potential of selective PI3Kdelta inhibitor in asthma discussed.

Inhibition of phosphoinositide 3-kinase delta attenuates allergic airway inflammation and hyperresponsiveness in murine asthma model.

P110delta phosphoinositide 3-kinase (PI3K) plays a pivotal role in the recruitment and activation of certain inflammatory cells. Recent findings revealed that the activity of p110delta also contributes to allergen-IgE-induced mast cell activation and vascular permeability. We investigated the role of p110delta in allergic airway inflammation and hyperresponsiveness using IC87114, a selective p110delta inhibitor, in a mouse asthma model. BALB/c mice were sensitized with OVA and, upon OVA aerosol challenge, developed airway eosinophilia, mucus hypersecretion, elevation in cytokine and chemokine levels, up-regulation of ICAM-1 and VCAM-1 expression, and airway hyperresponsiveness. Intratracheal administration of IC87114 significantly (P<0.05) attenuated OVA-induced influx into lungs of total leukocytes, eosinophils, neutrophils, and lymphocytes, as well as levels of IL-4, IL-5, IL-13, and RANTES in a dose-dependent manner. IC87114 also significantly (P<0.05) reduced the serum levels of total IgE and OVA-specific IgE and LTC(4) release into the airspace. Histological studies show that IC87114 inhibited OVA-induced lung tissue eosinophilia, airway mucus production, and inflammation score. In addition, IC87114 significantly (P<0.05) suppressed OVA-induced airway hyperresponsiveness to inhaled methacholine. Western blot analyses of whole lung tissue lysates shows that IC87114 markedly attenuated the OVA-induced increase in expression of IL-4, IL-5, IL-13, ICAM-1, VCAM-1, RANTES, and eotaxin. Furthermore, IC87114 treatment markedly attenuated OVA-induced serine phosphorylation of Akt, a downstream effector of PI3K signaling. Taken together, our findings implicate that inhibition of p110delta signaling pathway may have therapeutic potential for the treatment of allergic airway inflammation.

The involvement of VEGF in endothelial permeability: a target for anti-inflammatory therapy.

Many inflammatory mediators are known to contribute to increased vascular permeability during various phases of inflammation. Among these mediators, vascular endothelial growth factor (VEGF), also known as vascular permeability factor, plays an important role in vascular hyper-permeability, and several studies have demonstrated that modulation of VEGF function might contribute to a successful therapeutic approach to the treatment of inflammatory diseases. VEGF receptor monoclonal antibodies, glucocorticoids, leukotriene modifiers, cyclooxygenase-2 inhibitors and non-steroidal anti-inflammatory drugs have been studied for many years as VEGF-blocking drugs in inflammatory diseases in vitro and/or in vivo. The molecular and biological understanding of VEGF and preclinical or clinical trials of VEGF-blocking therapies raise hope that they may be useful as adjuncts to existing anti-inflammatory approaches in the regulation of inflammatory diseases.

PPAR-gamma modulates allergic inflammation through up-regulation of PTEN.

The ligand-activated nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) has been shown to regulate cell activation, differentiation, proliferation, and/or apoptosis. PPARgamma is also associated with anti-inflammatory responses. However, the signaling mechanism remains elusive. We have used a mouse model for asthma to determine the effect of PPARgamma agonists, rosiglitazone or pioglitazone, and PPARgamma on allergen-induced bronchial inflammation and airway hyperresponsiveness. Administration of PPARgamma agonists or adenovirus carrying PPARgamma cDNA (AdPPARgamma) reduced bronchial inflammation and airway hyperresponsiveness. Expression of PPARgamma was increased by ovalbumin (OVA) inhalation, and the increase was further enhanced by the administration of the PPARgamma agonists or AdPPARgamma. Levels of IL-4, IL-5, IL-13, and eosinophil cationic protein were increased after OVA inhalation, and the increased levels were significantly reduced by the administration of PPARgamma agonists or AdPPARgamma. The results also showed that the administration of PPARgamma agonists or AdPPARgamma up-regulated phosphatase and tensin homologue deleted on chromosome ten (PTEN) expression in allergen-induced asthmatic lungs. This up-regulation correlated with decreased phosphatidylinositol 3-kinase activity as measured by reduced phosphorylation of Akt. These findings demonstrate a protective role of PPARgamma in the pathogenesis of the asthma phenotype through regulation of PTEN expression.

Cysteinyl leukotriene receptor antagonist regulates vascular permeability by reducing vascular endothelial growth factor expression.

BACKGROUND: Inflammation of the asthmatic airway is usually accompanied by increased vascular permeability and plasma exudation. Cysteinyl leukotrienes (cysLTs) potently elicit increased vascular permeability in airways, leading to airway edema. Vascular endothelial growth factor (VEGF) is 1 of the most potent proangiogenic cytokines and also increases vascular permeability so that plasma proteins can leak into the extravascular space. However, the mechanisms by which cysLTs induce increased vascular permeability are not clearly understood. OBJECTIVE: An aim of the current study was to determine the role of the cysLTs, more specifically in the increase of vascular permeability. METHODS: We used a BALB/c mouse model of allergic asthma to examine effects of cysLT receptor antagonists on bronchial inflammation and airway hyperresponsiveness, more specifically on the increase of vascular permeability. RESULTS: These mice develop the following typical pathophysiological features of asthma in the lungs: increased numbers of inflammatory cells of the airways, airway hyperresponsiveness, increased vascular permeability, and increased levels of VEGF. Administration of cysLT receptor antagonists markedly reduced plasma extravasation and VEGF levels in allergen-induced asthmatic lungs. CONCLUSION: These results indicate that cysLT receptor antagonists modulate vascular permeability by reducing VEGF expression and suggest that cysLT receptor may regulate the VEGF expression.

The role of PTEN in allergic inflammation.

Bronchial asthma is a chronic inflammatory disease of the airways, characterized by airway eosinophilia, goblet cell hyperplasia with mucus hyper-secretion, and hyper-responsiveness to inhaled allergens and to non-specific stimuli. Eosinophil accumulation and subsequent activation in bronchial tissues play critical roles in the pathophysiology of bronchial asthma. Many inflammatory mediators attract and activate eosinophils via signal transduction pathways involving an enzyme phosphatidylinositol 3-kinase (PI3-kinase). Studies using wortmannin, a specific inhibitor of PI3-kinase, have revealed the involvement of PI3-kinase in the biochemical transduction of activation signals generated by many inflammatory mediators in eosinophils. Wortmannin prevents the development of airway inflammation, either by inhibiting the eosinophil infiltration of bronchial tissues or their activation on arrival. Phosphatase and tensin homologue deleted on chromosome 10 (PTEN) is part of a complex signaling system that affects a variety of important cell functions. PTEN opposes the action of PI3-kinase by dephosphorylating the signaling lipid phosphatidylinositol 3,4,5-triphosphate. Recently we have demonstrated that PTEN expression is diminished in airway epithelial cells of antigen-sensitized and -challenged mice. Administration of PI3-kinase inhibitors or adenoviruses carrying PTEN complementary DNA remarkably reduces eosinophil levels and inflammation. One likely mechanism for this reduction is PTEN-mediated eosinophil degranulation and suppression of interleukin (IL)-4 and IL-5. These findings indicate that use of PTEN may be a good therapeutic strategy for the management of allergic inflammation.

Doxycycline reduces airway inflammation and hyperresponsiveness in a murine model of toluene diisocyanate-induced asthma.

BACKGROUND: Toluene diisocyanate (TDI) is a leading cause of occupational asthma. Although considerable controversy remains regarding its pathogenesis, TDI-induced asthma is an inflammatory disease of the airways characterized by airway remodeling caused, at least in part, by an excess of extracellular matrix deposition in the airway wall. Matrix metalloproteinases (MMPs) are major proteolytic enzymes that are involved in extracellular matrix turnover because of their ability to cleave all proteins constituting extracellular matrix. Previous studies have reported that MMP-9 might play a role in chronic airway inflammation and remodeling in asthma. OBJECTIVE: An aim of the current study was to evaluate the effects of MMP-inhibiting antibiotic, doxycycline, and MMP inhibitors on hyperresponsiveness and inflammation of the airways in TDI-induced asthma. METHODS: We used a murine model for TDI-induced asthma to examine the effect of doxycycline or MMP inhibitors on bronchial inflammation and airway hyperresponsiveness. RESULTS: The following typical pathophysiologic features are observed in the lungs of the mice: airway inflammation, airway hyperresponsiveness, and increased expression of MMP-9 mRNA and protein. Administration of doxycycline and MMP inhibitors reduced all of these pathophysiologic findings. In addition, the increased phosphorylated Akt but not Akt protein levels in lung tissues after TDI inhalation were significantly reduced by the administration of doxycycline and MMP inhibitors. CONCLUSION: These findings suggest that doxycycline may reduce airway inflammation and hyperresponsiveness through phosphatidylinositol 3-kinase pathway in a murine model of TDI-induced asthma.

Matrix metalloproteinase inhibitor regulates inflammatory cell migration by reducing ICAM-1 and VCAM-1 expression in a murine model of toluene diisocyanate-induced asthma.

BACKGROUND: Matrix metalloproteinase-9 (MMP-9) has been reported to play a crucial role in the transmigration of neutrophils, lymphocytes, and eosinophils. Neutrophils, eosinophils, and lymphocytes migrate from the blood to the lungs in response to inflammatory mediators produced in the airways and are subsequently released into the circulation. This traffic is mediated by adhesion molecules. However, little is known about the migration of inflammatory cells through the endothelial and epithelial basement membranes in toluene diisocyanate (TDI)-induced asthma. OBJECTIVES: An aim of this study was to evaluate the effect of MMP inhibitors on the expression of ICAM-1 and VCAM-1 in the migration of inflammatory cells in a murine model of TDI-induced asthma. METHODS: We used a murine model to investigate TDI-induced asthma to examine the possible involvement of ICAM-1 and VCAM-1 in the pathogenesis of that disease and the effect of MMP inhibitors on the expression of ICAM-1 and VCAM-1. RESULTS: In mice, the following typical pathophysiologic features develop in the lungs: increased numbers of inflammatory cells and increased expression of MMP-9, ICAM-1, and VCAM-1 mRNA and protein. Administration of MMP inhibitors reduced the increased numbers of inflammatory cells and the increased expression of ICAM-1 and VCAM-1 mRNA expression and protein. In addition, MMP inhibitors significantly abrogated the increased expression of IL-1beta, IL-4, and TNF-alpha mRNA in lung tissues and levels of IL-1beta, IL-4, and TNF-alpha in bronchoalveolar lavage fluids after TDI inhalation. CONCLUSIONS: These results suggest that MMP inhibitors regulate inflammatory cell migration by reducing ICAM-1 and VCAM-1 expression and possibly also by suppressing IL-1beta, IL-4, and TNF-alpha expression.

Involvement of PTEN in airway hyperresponsiveness and inflammation in bronchial asthma.

Phosphatase and tensin homologue deleted on chromosome ten (PTEN) is part of a complex signaling system that affects a variety of important cell functions. PTEN blocks the action of PI3K by dephosphorylating the signaling lipid phosphatidylinositol 3,4,5-triphosphate. We have used a mouse model for asthma to determine the effect of PI3K inhibitors and PTEN on allergen-induced bronchial inflammation and airway hyperresponsiveness. PI3K activity increased significantly after allergen challenge. PTEN protein expression and PTEN activity were decreased in OVA-induced asthma. Immunoreactive PTEN localized in epithelial layers around the bronchioles in control mice. However, this immunoreactive PTEN dramatically disappeared in allergen-induced asthmatic lungs. The increased IL-4, IL-5, and eosinophil cationic protein levels in bronchoalveolar lavage fluids after OVA inhalation were significantly reduced by the intratracheal administration of PI3K inhibitors or adenoviruses carrying PTEN cDNA (AdPTEN). Intratracheal administration of PI3K inhibitors or AdPTEN remarkably reduced bronchial inflammation and airway hyperresponsiveness. These findings indicate that PTEN may play a pivotal role in the pathogenesis of the asthma phenotype.

The role of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in cryptogenic organizing pneumonia.

BACKGROUND: The processes observed in interstitial lung disease are associated with the production, deposition, and proteolysis of the extracellular matrix (ECM), which may lead to irreversible pulmonary structural remodeling or to appropriate repair without fibrosis. Matrix metalloproteinases (MMPs) and a tissue inhibitor of metalloproteinases (TIMPs) are known to regulate remodeling of the ECM and thus to be important in the process of lung fibrosis. Pulmonary structures are extensively remodeled in usual interstitial pneumonia (UIP), whereas severe architectural remodeling is minimally present in cryptogenic organizing pneumonia (COP). However, not much is known about the roles of MMP-9 and/or TIMP-1 in COP. METHODS: Levels of MMP-9, TIMP-1 and the molar ratio of MMP-9/TIMP-1 in BAL fluids were investigated in 11 patients with UIP, in 8 patients with COP, and in 10 control subjects. We checked the levels of MMP-9 and TIMP-1 by means of enzyme immunoassay, and the hydrolytic activity of MMP-9 in BAL fluids was measured by gelatin zymography. Further, we evaluated the expression of MMP-9 and TIMP-1 in lung tissue by immunohistochemistry. RESULTS: The concentrations of MMP-9 and TIMP-1 were significantly increased in patients with UIP and were even higher in patients with COP compared with control subjects. The levels of MMP-9 and TIMP-1 were significantly higher in patients with COP than in patients with UIP. The molar ratio of MMP-9/TIMP-1 was significantly higher in patients with COP than in control subjects. In patients with COP, the concentration of MMP-9 significantly correlated with the number of neutrophils and lymphocytes. Zymographic analysis revealed that the activity of the 92-kd pro-MMP-9 was increased in patients with UIP and was even higher in patients with COP, compared with control subjects. CONCLUSIONS: These data suggest that overproduction of MMP-9 and TIMP-1, and an imbalance between MMP-9 and TIMP-1, may have a role as diagnostic references in COP.

Contribution of vascular endothelial growth factor to airway hyperresponsiveness and inflammation in a murine model of toluene diisocyanate-induced asthma.

Isocyanate chemicals, including toluene diisocyanate (TDI), are currently the most common causes of occupational asthma. Although considerable controversy remains regarding its pathogenesis, TDI-induced asthma is characterized by hyperresponsiveness and inflammation of the airways. One of the histological hallmarks of inflammation is angiogenesis, but the possible role of vascular endothelial growth factor (VEGF), a potent angiogenic cytokine, in TDI-induced asthma is unknown. We developed a murine model to investigate TDI-induced asthma by performing two courses of sensitization with 3% TDI and one challenge with 1% TDI using ultrasonic nebulization to examine the potential involvement of VEGF in that disease. These mice develop the following typical pathophysiological features: airway hyperresponsiveness, airway inflammation, and increased VEGF levels in the airway. Administration of VEGFR inhibitors reduced all these pathophysiological symptoms. These results suggest that VEGF is one of the major determinants of TDI-induced asthma and that the inhibition of VEGF may be a good therapeutic strategy.