EGFR signaling is required for TGF-beta 1 mediated COX-2 induction in human bronchial epithelial cells

Administration of a combination of COX-2/TGF-β1 siRNAs induces hypertrophic scar fibroblast apoptosis through a TP53 mediated caspase pathway

Hypertrophic scar (HTS) formation is a pathological fibrotic skin disease, with no satisfactory treatments available currently. Inducing apoptosis of HTS-derived fibroblasts (HSFs) are becoming promising approaches. In this research, we aim to improve the technology with co-delivery COX-2 and TGF-β1 siRNAs and further investigate the underlying mechanism. Firstly, the HSFs were transfected with 1 µg/ml COX-2 and/or TGF-β1 siRNAs, and proved that the apoptosis of HSFs was greater induced by COX-2/TGF-β1 siRNAs than either COX-2 or TGF-β1 siRNA alone by flow cytometry. To investigate the impact of co-silencing TGF-β1 and COX-2 mRNA expression in vivo, we established HTSs model in rat tails. Our results confirmed that co-silencing of TGF-β1 and COX-2 mRNA expression could significantly alleviate the HTS formation in vivo. Furthermore, we explored the potential molecular mechanism and revealed that the protein levels of TP53, Bcl-2 and Caspase-3 were downregulated while Bax and Cleaved Caspase-3 were upregulated in the COX-2/TGF-β1 siRNA groups compared with HKP group. Taken together, our results demonstrated that simultaneous silencing of COX-2 and TGF-β1 expression by siRNAs induced HSF apoptosis through a TP53 mediated caspase pathway. Therefore, COX-2/TGF-β1 siRNAs might serve as a novel and effective therapeutic alternative for HTSs treatments.

Tonic ErbB signaling underlies TGFβ-induced activation of ERK and is required for lens cell epithelial to myofibroblast transition

Fibrosis is a major, but incompletely understood, component of many diseases. The most common vision-disrupting complication of cataract surgery involves differentiation of residual lens cells into myofibroblasts. In serum-free primary cultures of lens epithelial cells (DCDMLs), inhibitors of either ERK or of ErbB signaling prevent TGFβ from upregulating both early (fibronectin) and late (αSMA) markers of myofibroblast differentiation. TGFβ stimulates ERK in DCDMLs within 1.5 h. Kinase inhibitors of ErbBs, but not of several other growth factor receptors in lens cells, reduce phospho ERK to below basal levels in the absence or presence of TGFβ. This effect is attributable to constitutive ErbB activity playing a major role in regulating the basal levels pERK. Additional studies support a model in which TGFβ-generated reactive oxygen species serve to indirectly amplify ERK signaling downstream of tonically active ErbBs to mediate myofibroblast differentiation. ERK activity is in turn essential for expression of ErbB1 and ErbB2, major inducers of ERK signaling. By mechanistically linking TGFβ, ErbB, and ERK signaling to myofibroblast differentiation, our data elucidate a new role for ErbBs in fibrosis and reveal a novel mode by which TGFβ directs lens cell fate.

ERK1/2-mediated EGFR-signaling is required for TGFβ-induced lens epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs) plays a critical role in the pathogenesis of fibrotic cataract. Transforming growth factor-beta (TGFβ) is a potent inducer of this fibrotic process in lens. Recent studies in cancer progression have shown that in addition to activating the canonical Smad signaling pathway, TGFβ can also transactivate the epidermal growth factor receptor (EGFR) to enhance invasive cell migration. The present study aims to elucidate the involvement of EGFR-signaling in TGFβ-induced EMT in LECs. Treatment with TGFβ2 induced transdifferentiation of LECs into myofibroblastic cells, typical of an EMT. TGFβ2 induced the phosphorylation of the EGFR and upregulation of Egfr and Hb-egf gene expression. Pharmacologic inhibition of EGFR-signaling using PD153035 inhibited TGFβ-induced EMT, including the upregulation of mesenchymal markers and downregulation of epithelial markers. Crosstalk between TGFβ2-induced EGFR and ERK1/2 was evident, with both pathways impacting on Smad2/3-signaling. Our finding that TGFβ2 transactivates downstream EGFR-signaling reveals a previously unknown mechanism in the pathogenesis of cataract. Understanding the complex interplay between divergent canonical and non-canonical signaling pathways, as well as downstream target genes involved in TGFβ-induced EMT, will enable the development of more effective targeted therapies in the pharmacological treatment of cataract.

Depression, inflammation, and epidermal growth factor receptor (EGFR) status in metastatic non-small cell lung cancer: A pilot study

OBJECTIVE

Patients with stage IV non-small cell lung cancer (NSCLC) have high risk for depressive symptoms and major depressive disorder (MDD); however, those with epidermal growth factor receptor (EGFR) mutations may have decreased risk. The biological underpinning of this relationship is unknown. We examined differences in depression severity and MDD in patients with newly diagnosed stage IV NSCLC based on EGFR mutation status, and examined proinflammatory cytokines and growth factors known to play a role in cancer progression and depression.

METHODS

Fifty-five patients with newly diagnosed stage IV NSCLC completed self-report and clinician-administered depression assessments prior to receiving results of tumor genotyping. We measured serum levels of circulating biological markers of inflammation: IL-1β, IL-6, TGF-α, and TNF-α. We examined differences in depression severity, MDD, and inflammatory biomarkers in patients with and without EGFR mutations.

RESULTS

Patients with EGFR mutations (n=10) had lower depression severity (t[43]=2.38, p=0.03) than those without EGFR mutations (n=38) and fewer patients with EGFR mutations had concurrent MDD (2.08%) relative to those without mutations (27.08%). Patients with MDD had higher levels of TNF-α than those without MDD (t[40]=2.95, p=0.005). Those with EGFR mutations exhibited higher levels of TNF-α relative to those without EGFR mutations (t[35]=2.17, p=0.04).

CONCLUSIONS

Patients with stage IV NSCLC harboring an EGFR mutation exhibited elevated proinflammatory marker TNF-α, yet had lower depression severity than patients without EGFR mutations. More work is warranted to examine the interaction between tumor genotyping and inflammatory cytokines in the context of depression.

Deletion of cyclooxygenase-2 inhibits K-ras-induced lung carcinogenesis

The purpose of this study was to identify the role COX-2 plays in K-ras–induced lung carcinogenesis. We crossed COX-2–homozygous knockout mice with K-ras^LA1 (G12D) expressing mice to obtain COX-2–deficient mice with K-ras expression (K-ras/COX-2^−/− mice) and COX-2 wild type mice with K-ras expression (K-ras mice). At 3.5 months of age, the K-ras/COX-2^−/− mice had significantly fewer lung adenocarcinomas and substantially smaller tumors than K-ras mice. K-ras/COX-2^−/− mice also had significantly fewer bronchioalveolar hyperplasias than K-ras mice. Compared with lung tumors from K-Ras mice, the levels of prostaglandin E₂ (PGE₂) were significantly lower, whereas levels of the PGE₂ metabolite 13,14-dihydro-15-keto-PGE₂ were significantly higher, in lung tumors from K-ras/COX-2^−/− mice. In addition, K-ras/COX-2^−/− mice had strikingly lower rates of tumor cell proliferation and expressed less MEK and p-Erk1/2 protein than K-ras mice did. In line with this, knocking down COX-2 in mutant K-ras non-small cell lung cancer A549 cells reduced colony formation, PGE₂ synthesis and ERK phosphorylation compared to that of vector control cells. Taken together, these findings suggest that COX-2 deletion contributes to the repression of K-ras–induced lung tumorigenesis by reducing tumor cell proliferation, decreasing the production of PGE₂, and increasing the production of 13,14-dihydro-15-keto-PGE₂, possibly via the MAPK pathway. Thus, COX-2 is likely important in lung tumorigenesis, and COX-2 and its product, PGE₂, are potential targets for lung cancer prevention.

Activation of TRPV4 Regulates Respiration through Indirect Activation of Bronchopulmonary Sensory Neurons

Transient receptor potential vanilloid receptor 4 (TRPV4) is a calcium-permeable non-selective cation channel implicated in numerous physiological and pathological functions. This study aimed to investigate the effect of TRPV4 activation on respiration and to explore the potential involvement of bronchopulmonary sensory neurons. Potent TRPV4 agonist GSK1016790A was injected into right atrium in anesthetized spontaneously breathing rats and the changes in breathing were measured. Patch-clamp recording was performed to investigate the effect of GSK1016790A or another TRPV4 activator 4α-PDD on cultured rat vagal bronchopulmonary sensory neurons. Immunohistochemistry was carried out to determine the TRPV4-expressing cells in lung slices obtained from TRPV4-EGFP mice. Our results showed, that right-atrial injection of GSK1016790A evoked a slow-developing, long-lasting rapid shallow breathing in anesthetized rats. Activation of TRPV4 also significantly potentiated capsaicin-evoked chemoreflex responses. The alteration in ventilation induced by GSK1016790A was abolished by cutting or perineural capsaicin treatment of both vagi, indicating the involvement of bronchopulmonary afferent neurons. The stimulating and sensitizing effects of GSK1016790A were abolished by a selective TRPV4 antagonist GSK2193874 and also by inhibiting cyclooxygenase with indomethacin. Surprising, GSK1016790A or 4α-PDD did not activate isolated bronchopulmonary sensory neurons, nor did they modulate capsaicin-induced inward currents in these neurons. Furthermore, TRPV4 expression was found in alveolar macrophages, alveolar epithelial, and vascular endothelial cells. Collectively, our results suggest that GSK1016790A regulates the respiration through an indirect activation of bronchopulmonary sensory neurons, likely via its stimulation of other TRPV4-expressing cells in the lungs and airways.

Human airway smooth muscle cells secrete amphiregulin via bradykinin/COX-2/PGE2, inducing COX-2, CXCL8, and VEGF expression in airway epithelial cells

Human airway smooth muscle cells (HASMC) contribute to asthma pathophysiology through an increased smooth muscle mass and elevated cytokine/chemokine output. Little is known about how HASMC and the airway epithelium interact to regulate chronic airway inflammation and remodeling. Amphiregulin is a member of the family of epidermal growth factor receptor (EGFR) agonists with cell growth and proinflammatory roles and increased expression in the lungs of asthma patients. Here we show that bradykinin (BK) stimulation of HASMC increases amphiregulin secretion in a mechanism dependent on BK-induced COX-2 expression, increased PGE2 output, and the stimulation of HASMC EP2 and EP4 receptors. Conditioned medium from BK treated HASMC induced CXCL8, VEGF, and COX-2 mRNA and protein accumulation in airway epithelial cells, which were blocked by anti-amphiregulin antibodies and amphiregulin siRNA, suggesting a paracrine effect of HASMC-derived amphiregulin on airway epithelial cells. Consistent with this, recombinant amphiregulin induced CXCL8, VEGF, and COX-2 in airway epithelial cells. Finally, we found that conditioned media from amphiregulin-stimulated airway epithelial cells induced amphiregulin expression in HASMC and that this was dependent on airway epithelial cell COX-2 activity. Our study provides evidence of a dynamic axis of interaction between HASMC and epithelial cells that amplifies CXCL8, VEGF, COX-2, and amphiregulin production.

Macrophage migration inhibitory factor (MIF) enzymatic activity and lung cancer

The cytokine macrophage migration inhibitory factor (MIF) possesses unique tautomerase enzymatic activity, which contributes to the biological functional activity of MIF. In this study, we investigated the effects of blocking the hydrophobic active site of the tautomerase activity of MIF in the pathogenesis of lung cancer. To address this, we initially established a Lewis lung carcinoma (LLC) murine model in Mif-KO and wild-type (WT) mice and compared tumor growth in a knock-in mouse model expressing a mutant MIF lacking enzymatic activity (Mif (P1G)). Primary tumor growth was significantly attenuated in both Mif-KO and Mif (P1G) mice compared with WT mice. We subsequently undertook a structure-based, virtual screen to identify putative small molecular weight inhibitors specific for the tautomerase enzymatic active site of MIF. From primary and secondary screens, the inhibitor SCD-19 was identified, which significantly attenuated the tautomerase enzymatic activity of MIF in vitro and in biological functional screens. In the LLC murine model, SCD-19, given intraperitoneally at the time of tumor inoculation, was found to significantly reduce primary tumor volume by 90% (p < 0.001) compared with the control treatment. To better replicate the human disease scenario, SCD-19 was given when the tumor was palpable (at d 7 after tumor inoculation) and, again, treatment was found to significantly reduce tumor volume by 81% (p < 0.001) compared with the control treatment. In this report, we identify a novel inhibitor that blocks the hydrophobic pocket of MIF, which houses its specific tautomerase enzymatic activity, and demonstrate that targeting this unique active site significantly attenuates lung cancer growth in in vitro and in vivo systems.

TGFβ can stimulate the p(38)/β-catenin/PPARγ signaling pathway to promote the EMT, invasion and migration of non-small cell lung cancer (H460 cells)

Signaling pathway(s) responsible for transforming growth factor β (TGFβ)-induced epithelial mesenchymal transition (EMT), invasion and migration of H460 cells (non-small cell lung cancer/NSCLC) was identified in the study. The results showed that TGFβ-induced p(38)/β-catenin/PPARγ signaling pathway played a critical role in the promotion of EMT, invasion and migration of H460 cells. All these pathological outcomes attributed to PPARγ-increased expression of p-EGFR, p-c-MET and Vimentin and the decrease of E-cadherin. Transforming growth factor β and p(38)-induced β-catenin not only stimulated the expression of PPARγ but also physically interacted with it. Blocking the ligand binding domain of PPARγ (with GW9662) could significantly interfere the binding between PPARγ and β-catenin, and interrupt the nuclear infiltration of both factors. These findings suggested that β-catenin was an upstream regulator and a ligand of PPARγ, and the binding between these two molecules was critical for their nuclear infiltration. Transforming growth factor β-induced tumor invasion and migration was also seen in U373 cells (brain glioma, with high inducible PPARγ) in a PPARγ-dependent manner, but not in CH27 cells (squamous NSCLC, with low PPARγ). PPARγ shRNA, GW9662, JW67 and 2,4-diaminoquinazoline were all revealed to have important values in the control of the intrinsic and TGFβ-induced EMT, tumor invasion and migration of H460 cells. The results further suggested that PPARγ and β-catenin may be the potential markers for the early diagnosis and/or treatment of metastatic tumors.

The Effect of Helicobacter pylori on Epidermal Growth Factor Receptor-Induced Signal Transduction and the Preventive Effect of Celecoxib in Gastric Cancer Cells

Background/Aims

Helicobacter pylori infection induces cyclooxygenase-2 (COX-2) and epidermal growth factor receptor (EGFR) overexpression, and these factors may engage in cross-talk. The aim of the present study was to evaluate the effect of H. pylori on EGFR signaling pathways and to determine whether celecoxib has an inhibitory effect on this pathway.

Methods

The AGS cell line was cocultured with H. pylori G27 and the isogenic cagE- mutant. The expression of COX-2, EGFR, heparin binding-epidermal growth factor (HB-EGF), and transforming growth factor-β (TGF-β) was measured by real time-polymerase chain reaction (RT-PCR). Next, Western blot analyses of COX-2, EGFR, total Akt, phosphorylated Akt (pAkt), and phosphorylated glycogen synthase kinase-3β (pGSK3β) were performed after incubating H. pylori-treated AGS cells for 24 hours with various concentrations of celecoxib (0, 10, 20, and 30 µmol/L).

Results

H. pylori infection upregulated the mRNA levels of COX-2, EGFR, HB-EGF, and TGF-β, as detected by RT-PCR. However, AGS cells treated with cagE- mutants, which have a defective type IV secretion system, did not exhibit EGFR upregulation. Celecoxib had inhibitory effects on the H. pylori-induced overexpression of COX-2 (p=0.015), EGFR (p=0.025), pAkt (p=0.025), and pGSK3β (p=0.029) by Western blot analysis.

Conclusions

H. pylori with an intact type IV secretion system activated the COX-2 and EGFR-Akt pathways in the AGS cell line. As celecoxib exhibited inhibitory effects on the EGFR signaling pathway, the cross-talk of COX-2 and EGFR likely mediates H. pylori-induced gastric cancer.

Amphiregulin, an epidermal growth factor receptor ligand, plays an essential role in the pathogenesis of transforming growth factor-β-induced pulmonary fibrosis

Dysregulated amphiregulin (AR) expression and EGR receptor (EGFR) activation have been described in animal models of pulmonary fibrosis and in patients with idiopathic pulmonary fibrosis. However, the exact role of AR in the pathogenesis of pulmonary fibrosis has not been clearly defined. Here, we show that a potent profibrogenic cytokine TGF-β1 significantly induced the expression of AR in lung fibroblasts in vitro and in murine lungs in vivo. AR stimulated NIH3T3 fibroblast cell proliferation in a dose-dependent manner. Silencing of AR expression by siRNA or chemical inhibition of EGFR signaling, utilizing AG1478 and gefitinib, significantly reduced the ability of TGF-β1 to stimulate fibroblast proliferation and expression of α-smooth muscle actin, collagen, and other extracellular matrix-associated genes. TGF-β1-stimulated activation of Akt, ERK, and Smad signaling was also significantly inhibited by these interventions. Consistent with these in vitro findings, AR expression was impressively increased in the lungs of TGF-β1 transgenic mice, and either siRNA silencing of AR or chemical inhibition of EGFR signaling significantly reduced TGF-β1-stimulated collagen accumulation in the lung. These studies showed a novel regulatory role for AR in the pathogenesis of TGF-β1-induced pulmonary fibrosis. In addition, these studies suggest that AR, or AR-activated EGFR signaling, is a potential therapeutic target for idiopathic pulmonary fibrosis associated with TGF-β1 activation.

[Advances of targeted therapy based on estrogen receptor signaling pathway in lung cancer]

Increasing evidence indicates that estrogen promotes tumor growth in both estrogen target organs and non-target organs. Estrogen regulates cell proliferation and differentiation via two different receptors, estrogen receptors α and β (ERα and ERβ). In recent decades, with the clarification of the ERα-mediated signaling pathways in breast cancer, targeted therapy through these pathways have successfully been used in clinical application. Tamoxifen, the classic representative, is a selective estrogen receptor modulator (SERM). Along with the elucidation of the role of estrogen in the pathophysiology of lung cancer, targeted lung cancer treatment based on the ER signaling pathways is also gradually being applied and it could become an important part of the comprehensive treatment for lung cancer.

Human cytomegalovirus and mucoepidermoid carcinoma of salivary glands: cell-specific localization of active viral and oncogenic signaling proteins is confirmatory of a causal relationship

Human cytomegalovirus (hCMV) infection is common. Although still controversial, there is growing evidence that active hCMV infection is associated with a variety of malignancies, including brain, breast, lung, colon, and prostate. Given that hCMV is frequently resident in salivary gland (SG) ductal epithelium, we hypothesized that hCMV would be important to the pathogenesis of SG mucoepidermoid carcinoma (MEC). This was initially supported by our finding that purified CMV induces malignant transformation in SG cells in an in vitro mouse model, and utilizes a pathogenic pathway previously reported for human MEC. Here we present the histologic and molecular characterizations of 39 human SG MECs selected randomly from a repository of cases spanning 2004-2011. Serial sections were obtained from formalin-fixed, paraffin embedded, tissue blocks from previous incisional or excisional biopsies. Immunohistochemical assays were performed for active hCMV proteins (IE1 and pp65) and the activated COX/AREG/EGFR/ERK signaling pathway. All four prospective causal criteria for viruses and cancer are fully satisfied: (1) protein markers for active hCMV are present in 97% of MECs; (2) markers of active hCMV are absent in non-neoplastic SG tissues; (3) hCMV-specific proteins (IE1, pp65) are in specific cell types and expression is positively correlated with severity; (4) hCMV correlates and colocalizes with an upregulation and activation of an established oncogenic signaling pathway (COX/AREG/EGFR/ERK). Thus, the evidential support reported here and previously in a mouse model is strongly confirmatory of a causal relationship between hCMV and SG mucoepidermoid carcinoma. To our knowledge, this is the first demonstration of hCMV's role in human oncogenesis that fully responds to all of Koch's Postulates as revised for viruses and cancer. In the absence of any contrary evidence, hCMV can reasonably be designated an "oncovirus."

Expression levels of estrogen receptor beta in conjunction with aromatase predict survival in non-small cell lung cancer

Estrogen signaling pathways may play a significant role in the pathogenesis of non-small cell lung cancers (NSCLC) as evidenced by the expression of aromatase and estrogen receptors (ERα and ERβ) in many of these tumors. Here we examine whether ERα and ERβ levels in conjunction with aromatase define patient groups with respect to survival outcomes and possible treatment regimens. Immunohistochemistry was performed on a high-density tissue microarray with resulting data and clinical information available for 377 patients. Patients were subdivided by gender, age and tumor histology, and survival data was determined using the Cox proportional hazards model and Kaplan-Meier curves. Neither ERα nor ERβ alone was predictor of survival in NSCLC. However, when coupled with aromatase expression, higher ERβ levels predicted worse survival in patients whose tumors expressed higher levels of aromatase. Although this finding was present in patients of both genders, it was especially pronounced in women ≥ 65 years old, where higher expression of both ERβ and aromatase indicated a markedly worse survival rate than that determined by aromatase alone. Expression of ERβ together with aromatase has predictive value for survival in different gender and age subgroups of NSCLC patients. This predictive value is stronger than each individual marker alone. Our results suggest treatment with aromatase inhibitors alone or combined with estrogen receptor modulators may be of benefit in some subpopulations of these patients.

Regulation of the arachidonic acid mobilization in macrophages by combustion-derived particles

BACKGROUND

Acute exposure to elevated levels of environmental particulate matter (PM) is associated with increasing morbidity and mortality rates. These adverse health effects, e.g. culminating in respiratory and cardiovascular diseases, have been demonstrated by a multitude of epidemiological studies. However, the underlying mechanisms relevant for toxicity are not completely understood. Especially the role of particle-induced reactive oxygen species (ROS), oxidative stress and inflammatory responses is of particular interest.In this in vitro study we examined the influence of particle-generated ROS on signalling pathways leading to activation of the arachidonic acid (AA) cascade. Incinerator fly ash particles (MAF02) were used as a model for real-life combustion-derived particulate matter. As macrophages, besides epithelial cells, are the major targets of particle actions in the lung murine RAW264.7 macrophages and primary human macrophages were investigated.

RESULTS

The interaction of fly ash particles with macrophages induced both the generation of ROS and as part of the cellular inflammatory responses a dose- and time-dependent increase of free AA, prostaglandin E2/thromboxane B2 (PGE2/TXB2), and 8-isoprostane, a non-enzymatically formed oxidation product of AA. Additionally, increased phosphorylation of the mitogen-activated protein kinases (MAPK) JNK1/2, p38 and ERK1/2 was observed, the latter of which was shown to be involved in MAF02-generated AA mobilization and phosphorylation of the cytosolic phospolipase A2. Using specific inhibitors for the different phospolipase A2 isoforms the MAF02-induced AA liberation was shown to be dependent on the cytosolic phospholipase A2, but not on the secretory and calcium-independent phospholipase A2. The initiation of the AA pathway due to MAF02 particle exposure was demonstrated to depend on the formation of ROS since the presence of the antioxidant N-acetyl-cysteine (NAC) prevented the MAF02-mediated enhancement of free AA, the subsequent conversion to PGE2/TXB2 via the induction of COX-2 and the ERK1/2 and JNK1/2 phosphorylation. Finally we showed that the particle-induced formation of ROS, liberation of AA and PGE2/TXB2 together with the phosphorylation of ERK1/2 and JNK1/2 proteins was decreased after pre-treatment of macrophages with the metal chelator deferoxamine mesylate (DFO).

CONCLUSIONS

These results indicate that one of the primary mechanism initiating inflammatory processes by incinerator fly ash particles seems to be the metal-mediated generation of ROS, which triggers via the MAPK cascade the activation of AA signalling pathway.

Suppression of amphiregulin/epidermal growth factor receptor signals contributes to the protective effects of quercetin in cirrhotic rats

The hepatic wound-healing response to chronic noxious stimuli may lead to liver fibrosis, a key feature of the preneoplastic cirrhotic liver. Fibrogenic cells activate in response to a variety of cytokines, growth factors, and inflammatory mediators. The involvement of members of the epidermal growth factor family in this process has been suggested. Amphiregulin is an epidermal growth factor receptor (EGFR) ligand specifically induced upon liver injury. We investigated the effects of quercetin on the amphiregulin/EGFR signal and on the activation of downstream pathways leading to cell growth. Rats were divided into 4 groups (8 rats/group): rats subjected to common bile duct ligation (CBDL), Sham (rats subjected to simulated CBDL), quercetin-treated sham, and quercetin-treated CBDL (CBDL-Q). Quercetin (50 mg/kg i.p. injection) was administered daily for 2 wk starting on d 14 after surgery. Overexpression of amphiregulin, EGFR, TNFα, IL-6, TGFβ, platelet-derived growth factor (PDGF), extracellular regulated kinase, protein kinase B (Akt), cycloxygenase (COX)-2, and glioma-associated oncogenes (GLI)-1 and-2 were observed in liver of CBDL rats after 4 wk of bile duct ligation. CBDL-Q rats had a significantly diminished expression of amphiregulin and EGFR compared with untreated CBDL rats. Furthermore, mRNA levels of TNFα, IL-6, TGFβ, and PDGF and the protein content of COX-2, GLI-1, and GLI-2 were significantly lower in CBDL-Q rats than in untreated CBDL rats. The findings indicate that quercetin ameliorated activation of survival pathways and downregulated the expression of genes related to inflammation and precancerous conditions. Suppression of amphiregulin/EGFR signals may contribute to this effect.

Small molecule inhibitors of the host cell COX/AREG/EGFR/ERK pathway attenuate cytomegalovirus-induced pathogenesis

As with other herpesviruses, human cytomegalovirus (hCMV) has the ability to establish lifelong persistence and latent infection following primary exposure, salivary glands (SMGs) being the primary site of both. In the immunocompromised patient, hCMV is a common cause of opportunistic infections, and subsequent morbidity and mortality. Elucidating the molecular pathogenesis of CMV-induced disease is critical to the development of more effective and safer drug therapies. In the present study, we used a novel mouse postnatal SMG organ culture model of mCMV-induced dysplasia to investigate a candidate signaling network suggested by our prior studies (COX-2/AREG/EGFR/ERK). The objective was to employ small molecule inhibitors to target several key steps in the autocrine loop, and in this way ameliorate pathology. Our results indicate that upregulation of ERK phosphorylation is necessary for initial mCMV-induced pathogenesis, and that ErbB receptor family phosphorylation and downstream signaling are highly relevant targets for drug discovery.

EGFR and COX-2 protein expression in non-small cell lung cancer and the correlation with clinical features

Background

To evaluate the expression of EGFR and COX-2 and their correlation with prognosis in NSCLC

Methods

The paraffin embedded tumor samples of 50 NSCLC patients receiving radical resection were analyzed immunohistochemically for EGFR and COX-2 expression and their prognostic values were explored.

Results

The positive rate of EGFR protein in NSCLC tumor cells was 46%, which was significantly higher than its expression in normal lung (p = 0.0234) and paracancerous tissues (p = 0.020). EGFR expression was significantly higher in nodal positive than in nodal negative patients (p = 0.04). The mean survival time for EGFR positive patients (31 months) was significantly lower than that for patients with EGFR negative expression (48 months) (p = 0.008,). In patients receiving post-operation thoracic irradiation, the mean survival time for EGFR positive patients was significantly lower than that for patients without EGFR positive expression (25 vs. 48 months, P = 0.004). The positive rate of COX-2 protein expression in NSCLC tumor cells was 90%, which was significantly higher than that in normal tissue(p = 0.00) and paracancerous tissue (p = 0.00). There was no correlation between COX-2 expression and patient survival, and no correlation between COX-2 and EGFR protein expression (P = 0.555).

Conclusions

COX-2 and EGFR are over-expressed in NSCLC. EGFR is an independent prognostic factor and a predictive factor for radiotherapy response in NSCLC.

The role of prostaglandin E2 (PGE 2) in toll-like receptor 4 (TLR4)-mediated colitis-associated neoplasia

Background

We have previously found that TLR4-deficient (TLR4-/-) mice demonstrate decreased expression of mucosal PGE ₂ and are protected against colitis-associated neoplasia. However, it is still unclear whether PGE ₂ is the central factor downstream of TLR4 signaling that promotes intestinal tumorigenesis. To further elucidate critical downstream pathways involving TLR4-mediated intestinal tumorigenesis, we examined the effects of exogenously administered PGE ₂ in TLR4-/- mice to see if PGE ₂ bypasses the protection from colitis-associated tumorigenesis.

Method

Mouse colitis-associated neoplasia was induced by azoxymethane (AOM) injection followed by two cycles of dextran sodium sulfate (DSS) treatment. Two different doses of PGE ₂ (high dose group, 200 μg, n = 8; and low dose group, 100 μg, n = 6) were administered daily during recovery period of colitis by gavage feeding. Another group was given PGE ₂ during DSS treatment (200 μg, n = 5). Inflammation and dysplasia were assessed histologically. Mucosal Cox-2 and amphiregulin (AR) expression, prostanoid synthesis, and EGFR activation were analyzed.

Results

In control mice treated with PBS, the average number of tumors was greater in WT mice (n = 13) than in TLR4-/- mice (n = 7). High dose but not low dose PGE ₂ treatment caused an increase in epithelial proliferation. 28.6% of PBS-treated TLR4-/- mice developed dysplasia (tumors/animal: 0.4 ± 0.2). By contrast, 75.0% (tumors/animal: 1.5 ± 1.2, P < 0.05) of the high dose group and 33.3% (tumors/animal: 0.3 ± 0.5) of the low dose group developed dysplasia in TLR4-/- mice. Tumor size was also increased by high dose PGE ₂ treatment. Endogenous prostanoid synthesis was differentially affected by PGE ₂ treatment during acute and recovery phases of colitis. Exogenous administration of PGE ₂ increased colitis-associated tumorigenesis but this only occurred during the recovery phase. Lastly, PGE ₂ treatment increased mucosal expression of AR and Cox-2, thus inducing EGFR activation and forming a positive feedback mechanism to amplify mucosal Cox-2.

Conclusions

These results highlight the importance of PGE ₂ as a central downstream molecule involving TLR4-mediated intestinal tumorigenesis.

PGE(2) contributes to TGF-beta induced T regulatory cell function in human non-small cell lung cancer

CD4(+)CD25(bright) regulatory T cells (T(reg)) play an important role in cancer-mediated immunosuppression. We and others have previously shown that prostaglandin E2 (PGE(2)) and transforming growth factor beta (TGF-beta) induce CD4(+)CD25(bright)FOXP3(+)T(reg). Based on these studies, we investigated the requirement for PGE(2) in Treg induction by TGF-beta. TGF-beta stimulation of human CD4(+) T cells induced COX-2-dependent production of PGE(2). PGE(2)-neutralizing antibody treatment significantly reduced the suppressive function of TGF-beta-induced T(reg) (TGF-beta-T(reg)) in vitro. TGF-beta concentration measured in the plasma of non-small cell lung cancer (NSCLC) patients directly correlated with the frequency of circulating CD4(+)CD25(bright)FOXP3(+)T cells. Flow cytometry analysis showed increased FOXP3 expression in circulating CD4(+)CD25(+)HLA-DR- cells of lung cancer patients compared to control subjects. Immunohistochemical analysis revealed co-expression of TGF-beta, COX-2, and FOXP3 in serial sections from resected lung tumor tissues. All together these observations suggest interplay between TGF-beta and COX-2 in the induction of T(reg) activities. Interrupting TGF-beta and PGE(2) signaling may be important in therapeutic interventions that aim to limit T(reg)function in lung cancer.

Tracheal Basal cells: a facultative progenitor cell pool

Analysis of lineage relationships in the naphthalene-injured tracheal epithelium demonstrated that two multipotential keratin 14-expressing cells (K14ECs) function as progenitors for Clara and ciliated cells. These K14EC were distinguished by their self-renewal capacity and were hypothesized to reside at the stem and transit amplifying tiers of a tissue-specific stem cell hierarchy. In this study, we used gene expression and histomorphometric analysis of the steady-state and naphthalene-injured trachea to evaluate the predictions of this model. We found that the steady-state tracheal epithelium is maintained by two progenitor cell pools, secretory and basal cells, and the latter progenitor pool is further divided into two subsets, keratin 14-negative and -positive. After naphthalene-mediated depletion of the secretory and ciliated cell types, the two basal cell pools coordinate to restore the epithelium. Both basal cell types up-regulate keratin 14 and generate a broadly distributed, abundant, and highly mitotic cell pool. Furthermore, basal cell proliferation is associated with generation of differentiated Clara and ciliated cells. The uniform distribution of basal cell progenitors and of their differentiated progeny leads us to propose that the hierarchical organization of tracheal reparative cells be revised to include a facultative basal cell progenitor pool.

The epidermal growth factor receptor: a link between inflammation and liver cancer

Epidemiological studies have established that many tumours occur in association with persistent inflammation. One clear example of inflammation-related cancer is hepatocellular carcinoma (HCC). HCC slowly unfolds on a background of chronic inflammation triggered by exposure to infectious agents (hepatotropic viruses), toxic compounds (ethanol), or metabolic impairment. The molecular links that connect inflammation and cancer are not completely known, but evidence gathered over the past few years is beginning to define the precise mechanisms. A central role for cytokines such as interleukin-6 (IL-6) and IL-1 (alpha and beta) in liver cancer has been established in experimental models. Besides these inflammatory mediators, mounting evidence points to the dysregulation of specific growth and survival-related pathways in HCC development. Among them is the pathway governed by the epidermal growth factor receptor (EGFR), which can be bound and activated by a broad family of ligands. Of special relevance is the fact that the EGFR engages in extensive crosstalk with other signaling pathways, serving as a "signaling hub" for an increasing list of growth factors, cytokines, and inflammatory mediators. In this review, we summarize the most recent evidences supporting a role for the EGFR system in inflammation-related cell signaling, with special emphasis in liver inflammation and HCC. The molecular dissection of the pathways connecting the inflammatory reaction and neoplasia will facilitate the development of novel and more effective antitumor strategies.

Targeting aromatase and estrogen signaling in human non-small cell lung cancer

Lung cancer has become increasingly common in women, and gender differences in the physiology and pathogenesis of the disease have suggested a role for estrogens. In the lung recent data have shown local production of estrogens from androgens via the action of aromatase enzyme and higher levels of estrogen in tumor tissue as compared with surrounding normal lung tissue. High levels of aromatase expression are also maintained in metastases as compared with primary tumors. Consistent with these findings, clinical studies suggest that aromatase expression may be a useful predictive biomarker for prognosis in the management of non-small cell lung cancer (NSCLC), the most common form of lung malignancy. Low levels of aromatase associate with a higher probability of long-term survival in older women with early stage NSCLC. Treatment of lung NSCLC xenografts in vivo with an aromatase inhibitor (exemestane) alone or combined with standard cisplatin chemotherapy elicits a significant reduction in tumor progression as compared to paired controls. Further, lung cancer progression is also governed by complex interactions between estrogen and growth factor signaling pathways to stimulate the growth of NSCLC as well as tumor-associated angiogenesis. We find that combination therapy with the multitargeted growth factor receptor inhibitor vandetanib and the estrogen receptor antagonist fulvestrant inhibit tumor growth more effectively than either treatment administered alone. Thus, incorporation of antiestrogen treatment strategies in standard antitumor therapies for NSCLC may contribute to improved patient outcome, an approach that deserves to be tested in clinical trials.

Inflammation and liver cancer: new molecular links

A connection between inflammation and cancer has been long suspected. Epidemiological studies have established that many tumors occur in association with chronic infectious diseases, and it is also known that persistent inflammation in the absence of infections increases the risk and accelerates the development of cancer. One clear example of inflammation-related cancer is hepatocellular carcinoma (HCC). HCC is a type tumor that slowly unfolds on a background of chronic inflammation mainly triggered by exposure to infectious agents (hepatotropic viruses) or to toxic compounds (ethanol). The molecular links that connect inflammation and cancer are not completely known, but evidences gathered over the past few years are beginning to define the precise mechanisms. In this article we review the most compelling evidences on the role of transcription factors such as NF-kappaB and STAT3, cytokines like IL-6 and IL-1alpha, ligands of the EGF receptor and other inflammatory mediators in cancer development, with special emphasis in HCC. The molecular dissection of the pathways connecting the inflammatory reaction and neoplasia will pave the way for better therapies to treat cancers.

Activation of macrophage peroxisome proliferator-activated receptor-gamma by diclofenac results in the induction of cyclooxygenase-2 protein and the synthesis of anti-inflammatory cytokines

Cyclooxygenase-2 (COX-2) is an inducible isoform of the COX family of enzymes central to the synthesis of pro-inflammatory prostaglandins. Induction of COX-2 is mediated by many endogenous and exogenous molecules that include pro-inflammatory cytokines and bacterial lipopolysaccharide (LPS). It has been demonstrated that COX-2 can also be induced by diclofenac in cultured J774.2 macrophages. This induction was delayed compared to COX-2 induced by LPS and paracetamol selectively inhibited activity of this protein. The aim of the present study was to determine the transcription factor involved in the production of COX-2 after treatment of J774.2 cells with 500 microM diclofenac. Pre-treatment of cells with the peroxisome proliferator-activated receptor-gamma (PPAR-gamma) antagonists GW9662 (0.1-1 microM) or biphenol A Diglycidyl Ether (100-200 microM) resulted in reduction of the induction of COX-2 by diclofenac, but not by LPS. Induction of COX-2 by the PPAR-gamma agonist 15deoxyDelta(12,14)prostaglandin J(2) was also reduced when the cells were pre-treated with the PPAR-gamma antagonists BADGE or GW9662. On the other hand, pre-treatment of cells with the nuclear factor-kappa-B (NF-kappaB) Super-repressor IkappaBalpha (150-600 nM) reduced the induction of COX-2 by LPS, but not by diclofenac. We, therefore, have identified that PPAR-gamma activation is a requirement for COX-2 induction after diclofenac stimulation of J774.2 cells. These results along with the finding that treatment of J774.2 macrophages with diclofenac resulted in the release of the anti-inflammatory cytokines, interleukin-10 and transforming growth factor-beta suggest that the diclofenac-induced COX-2 protein may possess anti-inflammatory actions.

COX-2/EGFR expression and survival among women with adenocarcinoma of the lung

Previous studies suggest that cyclooxygenase-2 (COX-2) expression may predict survival among patients with non-small cell lung cancer. COX-2 may interact with epidermal growth factor receptor (EGFR), suggesting that combined COX-2/EGFR expression may provide predictive value. The extent to which their independent or combined expression is associated with prognosis in women with adenocarcinoma of the lung is unknown. In the present study, we examined relationships between COX-2 expression (n = 238), EGFR expression (n = 158) and dual COX-2/EGFR expression (n = 157) and survival among women with adenocarcinoma of the lung. Overall survival was estimated by constructing Cox proportional hazards models adjusting for other significant variables and stratifying by stage at diagnosis and race. Clinical or demographic parameters were not associated with either COX-2 or EGFR expression. Patients with COX-2-positive tumors tended to have poorer prognosis than did patients with COX-2-negative tumors [hazard ratio (HR) 1.67, 95% confidence interval (CI) 1.01-2.78]. African-Americans with COX-2-positive tumors had a statistically non-significant higher risk of death than African-Americans with COX-2-negative tumors (HR 5.58, 95% CI 0.64-48.37). No association between COX-2 expression and survival was observed among Caucasians (HR 1.29, 95% CI 0.72-2.30). EGFR expression was associated with a 44% reduction in the risk of death (HR 0.56, 95% CI 0.32-0.98). COX-2-/EGFR+ tumor expression, but not COX-2+/EGFR+ tumor expression, was associated with survival when compared with other combined expression results. In conclusion, COX-2 and EGFR expression, but not combined COX-2+/EGFR+ expression, independently predict survival of women with adenocarcinoma of the lung.

Thioredoxin overexpression modulates remodeling factors in stress responses to cigarette smoke

Cigarette smoke (CS) generates reactive oxygen species (ROS) to produce oxidative damage of bronchial epithelial cells. Prolonged repair responses lead to airway remodeling and irreversible airflow limitation. Thioredoxin (TRX) is a redox protein that scavenges ROS to prevent oxidative stress. The aim of this study was to investigate the mechanisms underlying TRX-mediated CS-induced stress relevant to airway remodeling. Results showed that CS stimulated ROS generation and apoptosis in normal human bronchial epithelial (BEAS-2B) cells, and interfered with gene expression of remodeling factors, such as activation of transforming growth factor (TGF)-beta1, epidermal growth factor receptor (EGFR), and cyclin-dependent kinase inhibitor (p21), but repressed matrix metalloproteinases (MMP)-9. In particular, TRX-overexpressing bronchial epithelial (TRX-TD) cells reduced CS-induced apoptosis, and suppressed airway remodeling through attenuation of TGF-beta1, EGFR, and p21 and upregulation of MMP-9 expression. TGF-beta1 was shown to regulate MMP-9 as evidenced by suppression of MMP-9 protein induction by TGF-beta1 antibody. In addition, CS produced apoptosis of BEAS-2B cells via TRX oxidation, which activated signal transduction factors, including apoptosis signal-regulating kinase (ASK) 1 and c-Jun N-terminal kinase (JNK). In contrast, TRX-TD cells exposed to CS retained reduced-form TRX, and inactivated ASK1 and JNK to attenuate apoptosis. This study indicated TRX overexpression was involved in CS-induced apoptosis and prevented airway remodeling through ASK1-JNK inactivation and MMP-9 augmentation.

Transcriptional profiling of non-small cell lung cancer cells with activating EGFR somatic mutations

Background

Activating somatic mutations in epidermal growth factor receptor (EGFR) confer unique biologic features to non-small cell lung cancer (NSCLC) cells, but the transcriptional mediators of EGFR in this subgroup of NSCLC have not been fully elucidated.

Methodology/Principal Findings

Here we used genetic and pharmacologic approaches to elucidate the transcriptomes of NSCLC cell lines. We transcriptionally profiled a panel of EGFR-mutant and -wild-type NSCLC cell lines cultured in the presence or absence of an EGFR tyrosine kinase inhibitor. Hierarchical analysis revealed that the cell lines segregated on the basis of EGFR mutational status (mutant versus wild-type), and expression signatures were identified by supervised analysis that distinguished the cell lines based on mutational status (wild-type versus mutant) and type of mutation (L858R versus Δ746-750). Using an EGFR mutation-specific expression signature as a probe, we mined the gene expression profiles of two independent cohorts of NSCLC patients and found the signature in a subset. EGFR tyrosine kinase inhibitor treatment regulated the expression of multiple genes, and pharmacologic inhibition of the protein products of two of them (PTGS2 and EphA2) inhibited anchorage-independent growth in EGFR-mutant NSCLC cells.

Conclusions/Significance

We have elucidated genes not previously associated with EGFR-mutant NSCLC, two of which enhanced the clonogenicity of these cells, distinguishing these mediators from others previously shown to maintain cell survival. These findings have potential clinical relevance given the availability of pharmacologic tools to inhibit the protein products of these genes.