Unusual interleukin-4 and -13 signaling in human normal and tumor lung fibroblasts

The Expression Levels of IL-4/IL-13/STAT6 Signaling Pathway Genes and SOCS3 Could Help to Differentiate the Histopathological Subtypes of Non-Small Cell Lung Carcinoma

Background

The interleukin (IL)-4/IL-13/signal transducer and activator of transcription (STAT) 6 signaling pathway and the SOCS3 gene, one of its main regulators, constitute an important link between the inflammation process in the epithelial cells and inflammatory-related tumorigenesis. The present study is the first to evaluate IL-4, IL-13, STAT6, and SOCS3 mRNA expression in non-small cell lung carcinoma (NSCLC) histopathological subtypes.

Methods

Gene expression levels were assessed using TaqMan^® probes by quantitative reverse transcription PCR (qRT-PCR) in lung tumor samples and unchanged lung tissue samples.

Results

Increased expression of IL-4, IL-13, and STAT6 was observed in all histopathological NSCLC subtypes (squamous cell carcinoma [SCC], adenocarcinoma [AC], and large cell carcinoma [LCC]). Significantly higher expression of IL-13 and STAT6 (p = 0.019 and p = 0.008, respectively) was found in SCC than in LCC. No statistically significant differences were found for IL-4. Significantly higher SOCS3 expression was found in LCC than in AC (p = 0.027). A negative correlation (rho = –0.519) was observed for the STAT6 and SOCS3 genes in SCC (p = 0.005). No associations were found between gene expression and tumor staging (post-operative Tumor Node Metastasis [pTNM], American Joint Committee on Cancer [AJCC]), patients’ age, sex, or history of smoking.

Conclusions

As the number of LCC cases in our study was quite low, the statistically significant results obtained should be confirmed in a larger group of patients, particularly as the relationships identified between increased IL-4, IL-13, and STAT6 mRNA expression and decreased SOCS3 expression suggest that these genes may serve as potential diagnostic markers for differentiating between NSCLC histopathological subtypes.

Naturally Occurring Subclinical Endotoxemia in Humans Alters Adaptive and Innate Immune Functions through Reduced MAPK and Increased STAT1 Phosphorylation

Multiple studies have shown correlates of immune activation with microbial translocation and plasma LPS during HIV infection. It is unclear whether this activation is due to LPS, residual viral replication, or both. Few studies have addressed the effects of persistent in vivo levels of LPS on specific immune functions in humans in the absence of chronic viral infection or pathological settings such as sepsis. We previously reported on a cohort of HIV-negative men with subclinical endotoxemia linked to alterations in CD4/CD8 T cell ratio and plasma cytokine levels. This HIV-negative cohort allowed us to assess cellular immune functions in the context of different subclinical plasma LPS levels ex vivo without confounding viral effects. By comparing two samples of differing plasma LPS levels from each individual, we now show that subclinical levels of plasma LPS in vivo significantly alter T cell proliferative capacity, monocyte cytokine release, and HLA-DR expression, and induce TLR cross-tolerance by decreased phosphorylation of MAPK pathway components. Using this human in vivo model of subclinical endotoxemia, we furthermore show that plasma LPS leads to constitutive activation of STAT1 through autocrine cytokine signaling, suggesting that subclinical endotoxemia in healthy individuals might lead to significant changes in immune function that have thus far not been appreciated.

HGF/c-MET Axis in Tumor Microenvironment and Metastasis Formation

Tumor metastases are responsible for approximately 90% of all cancer-related deaths. Metastasis formation is a multistep process that requires acquisition by tumor cells of a malignant phenotype that allows them to escape from the primary tumor site and invade other organs. Each step of this mechanism involves a deep crosstalk between tumor cells and their microenvironment where the host cells play a key role in influencing metastatic behavior through the release of many secreted factors. Among these signaling molecules, Hepatocyte Growth Factor (HGF) is released by many cell types of the tumor microenvironment to target its receptor c-MET within the cells of the primary tumor. Many studies reveal that HGF/c-MET axis is implicated in various human cancers, and genetic and epigenetic gain of functions of this signaling contributes to cancer development through a variety of mechanisms. In this review, we describe the specific types of cells in the tumor microenvironment that release HGF in order to promote the metastatic outgrowth through the activation of extracellular matrix remodeling, inflammation, migration, angiogenesis, and invasion. We dissect the potential use of new molecules that interfere with the HGF/c-MET axis as therapeutic targets for future clinical trials in cancer disease.

Complex Primary Human Cell Systems for Drug Discovery

Phenotypic or biofunctional assays play an important role in drug discovery by helping to bridge the gap between high-throughput, target-based screening assays used for compound identification and more physiologically relevant in vivo disease models used for preclinical development. We have developed a standardised panel of phenotypic assays using primary human cells and co-cultures that model tissue and disease biology for characterization of drug leads. Here we show application of these assays for characterisation of clinical stage kinase inhibitors for rheumatoid arthritis, the recently approved JAK kinase inhibitor, tofacitinib, and the SYK kinase inhibitor, fostamatinib. We demonstrate how profiling in this assay panel can relate to clinical effects, both efficacy and safety related.

Janus kinase-3 dependent inflammatory responses in allergic asthma

Allergic asthma is a chronic inflammatory condition of the lung characterized by reversible airway obstruction, high serum immunoglobulin (Ig) E levels, and chronic airway inflammation. A number of cells including mast cells, T cells, macrophages and dendritic cells play a role in the pathogenesis of the disease. Janus kinase (JAK)-3, a non-receptor protein tyrosine kinase, traditionally known to mediate cytokine signaling, also regulates functional responses of these cells. In this review the role of JAK-3 in regulating various pathogenic processes in allergic asthma is discussed. We propose that targeting JAK-3 is a rationale approach to control the inflammatory responses of multiple cell types responsible for the pathogenesis of allergic asthma.

Proliferation of myofibroblasts in the stroma of renal oncocytoma

OBJECTIVES

Myofibroblasts are a vital component of stroma of many malignant neoplasms, but it is not yet established whether stromal myofibroblasts also exist in benign tumours such as oncocytoma of the kidney.

MATERIALS AND METHODS

Histomorphological and immunohistochemical analysis of 16 renal oncocytomas diagnosed at Chang Gung Memorial Hospital, Taiwan, has been performed.

RESULTS

Renal oncocytomas were composed of oncocytes, large cells with granular eosinophilic cytoplasm, arranged mostly in sheets, in tubulocystic or combined pattern. Few oncocytes appeared to be undergoing proliferation or apoptosis. MIB-1 and active caspase 3 indices were low, but higher in tumour than in surrounding non-tumour parenchyma (MIB-1: 0.93 +/- 0.09 versus 0.46 +/- 0.07, P < 0.001 and active caspase 3: 0.76 +/- 0.08 versus 0.41 +/- 0.09, P < 0.001). Wnt/beta-catenin signalling was not implicated in this neoplasm, as there was no loss of E-cadherin membranous localization or expression of intranuclear beta-catenin in the cells. Clumps of oncocytes were stained with periodic acid Schiff and had collagen I-, collagen III- and fibronectin-positive, but desmin- and human caldesmon-negative stromas. Importantly, alpha-smooth muscle actin (SMA)-immunostaining established the myofibroblastic nature of many of the stromal cells. Some of the myofibroblasts were also positive for MIB-1, indicating a proliferative role for them in the stroma.

CONCLUSIONS

Renal oncocytomas were composed of two independent compartments: benign oncocytes and pronounced fibrotic stroma, which consisted of proliferating myofibroblasts (SMA- and MIB-1-positive) which were associated with excessive deposition of extracellular matrix (periodic acid Schiff-component, collagen I-, collagen III- and fibronectin-positive, and desmin- and human caldesmon-negative).

Immune interactions in hepatic fibrosis

Liver cirrhosis is caused by iterative cycles of tissue injury, inflammation, and repair. Although most causes of acute hepatitis resolve without scarring, chronic hepatitis is associated with persistent inflammation and matrix remodeling, which leads to fibrosis and, eventually, cirrhosis. The mechanisms that govern wound healing involve interactions between the innate and adaptive immune systems and stromal cells within a microenvironment composed of cytokines, growth factors, and modified matricellular proteins. The immune system plays a central role in the regulation of fibrosis, tissue repair, and recovery that is vital for the maintenance of tissue homeostasis. Chronic inflammation and fibrosis are inextricably linked and the cellular interactions between immune effector cells, local fibroblasts, and tissue macrophages at sites of scar formation determine the outcome of liver injury and the development of scarring.

Stromal myofibroblasts are drivers of invasive cancer growth

Tissue integrity is maintained by the stroma in physiology. In cancer, however, tissue invasion is driven by the stroma. Myofibroblasts and cancer-associated fibroblasts are important components of the tumor stroma. The origin of myofibroblasts remains controversial, although fibroblasts and bone marrow-derived precursors are considered to be the main progenitor cells. Myofibroblast reactions also occur in fibrosis. Therefore, we wonder whether nontumorous myofibroblasts have different characteristics and different origins as compared to tumor-associated myofibroblasts. The mutual interaction between cancer cells and myofibroblasts is dependent on multiple invasive growth-promoting factors, through direct cell-cell contacts and paracrine signals. Since fibrosis is a major side effect of radiotherapy, we address the question how the main methods of cancer management, including chemotherapy, hormonotherapy and surgery affect myofibroblasts and by inference the surrogate endpoints invasion and metastasis.

Desmoplasia in different degrees of invasion of carcinoma ex-pleomorphic adenoma

Stroma desmoplasia was studied by immunohistochemistry for alpha-smooth muscle actin (alpha-SMA) in 17 instances of carcinoma ex-pleomorphic adenoma (CXPA) classified according to the presence of epithelial and myoepithelial cells and the degree of invasion: intracapsular, minimally and frankly invasive carcinoma. In "resident" pleomorphic adenoma, no desmoplasia was detected. In invasive areas of the intracapsular type of CXPA with only an epithelial component, desmoplasia started to be revealed by the presence of myofibroblasts close to the capsule. In the minimally invasive type, myofibroblasts were seen in the septum between islands of malignant cells and in focal peripheral areas of the tumor interpreted as the actual front of invasion. In the frankly invasive type of CXPA showing large blocks of cells, intense desmoplasia was seen, also separating the tumor cells from the neighboring normal tissue. In tumors with cords and/or small nests of cells, desmoplasia was very slight. In the invasive type of CXPA with a myoepithelial component, alpha-SMA expression was seen in the septum between the islands of cells. The expression was less intense and not present in all areas of the stroma. In CXPA with epithelial and myoepithelial cells, myofibroblasts were rarely seen in the septum separating sheets of cells. Thus, we may deduce that the presence of desmoplasia parallels the capacity of invasion of CXPA by epithelial cells, being minimum in the intracapsular and minimally invasive type of CXPA and increasing as the tumor becomes frankly invasive. Furthermore, we may also conclude that in CXPA with a myoepithelial component, desmoplasia is very rare.

IL-4 induces a wide-spectrum intracellular signaling cascade in CD8+T cells

IL-4 has distinct effects on the differentiation and functional properties of CD8+ T cells. In vivo studies have shown that it is critical for the development of protective memory responses against tumors and infections by Leishmania and Plasmodium parasites. The intracellular signaling events mediated by IL-4/IL-4 receptor (IL-4R) interactions on CD4+ T cells have been studied extensively; however, the nature of IL-4-induced signaling on CD8+ T cells has not been characterized. Using naïve, activated, as well as differentiated CD8+ T cells, we show that IL-4 has a strong in vivo and in vitro antiapoptotic effect on activated and resting CD8+ T cells. We demonstrate that IL-4 induces the phosphorylation of the IL-4R, which is followed by the activation of at least two distinct intracellular signaling cascades: the Jak1/STAT6 and the insulin receptor substrate/PI-3K/protein kinase B pathways. We also found that IL-4 induces the Jak3-mediated phosphorylation and nuclear migration of STAT1, STAT3, and STAT5 in naïve, activated, as well as differentiated, IFN-gamma-producing CD8+ T cells. The induction of this broad signaling activity in CD8+ T cells coincides with a transcriptional activity of suppressors of cytokine signaling genes, which are decreased significantly in comparison with CD4+ T cells. To our knowledge, this report constitutes the first comprehensive analysis of the signaling events that shape CD8+ T cell responses to IL-4.

Labeling fibroblasts with biotin-BSA-GdDTPA-FAM for tracking of tumor-associated stroma by fluorescence and MR imaging

Fibroblasts at the tumor-host interface can differentiate into myofibroblasts and pericytes, and contribute to the guidance and stabilization of endothelial sprouts. After intravenous administration of biotin-BSA-GdDTPA-FAM in mice with subcutaneous MLS human ovarian carcinoma tumors, the distribution of the macromolecular MRI/optical contrast material was confined to blood vessels in normal tissues, while it co-registered with alphaSMA-positive stroma tracks within the tumor. These alphaSMA-positive tumor-associated myofibroblasts and pericytes showed uptake of the contrast material into intracellular granules. We evaluated the use of this contrast material for in vitro labeling of tumor fibroblasts as an approach for tracking their involvement in angiogenesis. Fluorescence microscopy demonstrated internalization of the contrast material, and MRI revealed a significant increase in the R(1) relaxation rate of labeled fibroblasts. R(1) not only remained elevated for 2 weeks in culture, it also increased with cell proliferation, indicating prolonged retention of the contrast material and subsequent intracellular processing and redistribution of the material, and thereby enhancing MR contrast. Moreover, cells that were labeled ex vivo with MR contrast material and co-inoculated with tumor cells in mice were detected in vivo by MRI. Uptake of the contrast material was suppressed by nystatin, suggesting internalization by caveolae-mediated endocytosis. This study shows that labeling of fibroblasts with biotin-BSA-GdDTPA-FAM is feasible and would allow noninvasive in vivo tracking of fibroblasts during tumor angiogenesis and vessel maturation.

Mammary carcinoma provides highly tumourigenic and invasive reactive stromal cells

The progression of a lesion to a carcinoma is dependent on the engagement of 'reactive stroma' that provides structural and vascular support for tumour growth and also leads to tissue reorganization and invasiveness. The composition of reactive stroma closely resembles that of granulation tissue, and myofibroblasts are thought to play a critical role in driving the stromal reaction of invasive tumours as well as of physiological wound repair. In the present work, we established a myofibroblast-like cell line, named A17, from a mouse mammary carcinoma model in which tumourigenesis is triggered in a single step by the overexpression of HER-2/neu transgene in the epithelial compartment of mammary glands. We showed that although they derived from a tumour of epithelial origin and did not express HER-2/neu transgene, their subcutaneous injection into the backs of syngeneic mice gave rise to sarcomatoid tumours which expressed alpha-smooth muscle actin at the invasive edge. The expression of cytokeratin 14 suggested a myoepithelial origin but immunophenotypical profile, invasive and neoangiogenic potential of A17 cells and tumours showed many similarities with the reactive stroma that occurs in wound repair and in cancerogenesis. Our results suggest that epithelial tumours have the potential to develop highly tumourigenic and invasive reactive stromal cells and our cell line represents a novel, effective model for studying epithelial-stromal interaction and the role of myofibroblasts in tumour development.

Aberrant Stat3 signaling by interleukin-4 in malignant glioma cells: involvement of IL-13Ralpha2

Interleukin (IL)-4 exhibits antitumor activity in rodent experimental gliomas, which is likely mediated by the actions of IL-4 on a variety of immune cells present in and around the tumor masses. Here, we show that IL-4, which activates Stat6 in normal human astrocytes and in a variety of other cells, induces an aberrant activation of Stat3 in glioblastoma multiforme (GBM) cells but not in normal human astrocytes. Previously, we have shown that autocrine IL-6 signaling induces a persistent activation of Stat3. Now, we show that Stat3 is further activated by IL-4 stimulation of GBM cells. Expression of IL-13Ralpha2, a decoy receptor for IL-13 that partly blocks IL-4-mediated activation of Stat6 in GBM cells, up-regulates the activation of Stat3 as shown by a small interfering RNA-mediated inhibition of IL-13Ralpha2 expression. In addition, transient expression of the IL-13Ralpha2 transgene in 293T cells increases the IL-4-mediated activation of Stat3 and subsequent expression of Stat3-targeted gene. Coimmunoprecipitation results reveal that IL-13Ralpha2-mediated activation of Stat3 does not require a direct physical interaction between Stat3 and IL-13Ralpha2. Chromatin immunoprecipitation assay employing anti-Stat3 antibody confirms the in vivo binding of activated Stat3 to the promoters of genes that encode antiapoptotic proteins Bcl-2, Bcl-x(L), and Mcl-1. IL-4 significantly up-regulates of the steady-state levels of Bcl-2, Bcl-x(L), and Mcl-1 in GBM cells. These results indicate that IL-4/IL-13 receptor-mediated Stat3 signaling may contribute to the pathogenesis of GBM cells by modulating the expression of the Bcl-2 family of antiapoptotic proteins.

Determination of interleukin-4-responsive region in the human cytochrome P450 2E1 gene promoter

Cytochrome P450 2E1 (CYP2E1) gene expression is known to be induced by interleukin-4 (IL4) and repressed by inflammatory cytokines, such as interleukin-1beta3 (IL1beta3) in human hepatocytes. The mechanisms involved in these transcriptional regulations remain elusive. In order to study these mechanisms, various constructs of the human CYP2E1 promoter were prepared and transfected into the human HepG2 hepatoma cell line. Our findings revealed that an IL4-responsive region of 128bp (-671/-544) was required to mediate induction by IL4. IL1beta caused moderate but significant decrease of the promoter activity, which was abolished when the two cytokines were combined. The IL1beta inhibitory effect is mediated through a regulatory sequence independent of that of IL4. Furthermore, by using specific signaling pathway inhibitors, we demonstrated that IL4 activation required protein kinase C (PKC) activation. In addition, our results suggest that induction by IL4 was not dependent on a single binding site but rather on a complex region which includes putative binding sites for signal transducer and activator of transcription (STAT)6, activator protein (AP)-1, nuclear factor kappa-B (NFkappaB), nuclear factor of activated T cells (NFAT) and CCAAT enhancer binding protein (C/EBP). Electrophoretic mobility shift assays suggest that AP1 and NFAT transcription factors are able to bind to three sites in the IL4-responsive region.

Endogenous IL-15 Sustains Recruitment of IL-2Rβ and Common γ and IL-2-Mediated Chemokine Production in Normal and Inflamed Human Gingival Fibroblasts

We recently reported that anti-IL-15 neutralizing mAb has been shown to inhibit production of MCP-1 in response to IL-2 from normal human gingival fibroblasts (HGF), the major constituent of gingival tissue. In the present study, we examined the expression of IL-2R and IL-15R subunits in HGF from normal and inflamed regions and the role of endogenous IL-15 in IL-2-mediated signaling. Normal HGF expressed IL-2Rbeta and common gamma-chain (gammac) but not IL-2Ralpha or IL-15Ralpha, whereas inflamed HGF expressed IL-2Ralpha, IL-15Ralpha, IL-2Rbeta, and gammac, as assessed by RT-PCR and flow cytometry. Exogenous IL-2 and IL-15 induced production of MCP-1 but not IL-8 in normal HGF, and induced the production of both chemokines in inflamed HGF. Both HGF constitutively transcribed the 48 aa-IL-15 isoform, and the isoform was not actively secreted but rather existed as a membrane-bound form. Pretreatment with anti-IL-15 neutralizing mAb for 24 h completely inhibited the production of MCP-1 induced by IL-2 and IL-15 and IL-2-induced phosphorylation of Jak 1 and 3 in HGF. The pretreatment and RNA interference targeted to IL-15 mRNA resulted in total inhibition of the IL-2Rbeta and gammac expression at mRNA and protein levels. Furthermore, excess amounts of IL-2 restored the inhibitory effect of anti-IL-15, inhibition of NF-kappaB abrogated the expression of IL-2Rbeta and gammac, and IL-2-induced-nuclear translocation of NF-kappaB was completely inhibited by the RNA interference in HGF. These results suggest that endogenous membrane-bound IL-15 sustains recruitment of IL-2Rbeta and gammac through activation of NF-kappaB in HGF.

STAT-1 is activated by IL-4 and IL-13 in multiple cell types

While interleukin-4 (IL-4) and interleukin-13 (IL-13) can utilize a common receptor, composed of IL-4Ralpha and IL-13Ralpha1, IL-4 can also signal through a receptor with IL-4Ralpha and the common gamma chain (gammaC) as its subunits. IL-4 and IL-13 have been reported to elicit similar biological effects in a number of settings, including stimulating Ig isotype switching to IgE and inducing chemokines and cytokines in a variety of cell types whereas, depending on the receptor expression on responder cells, differential effects such as induction of type II helper T cell differentiation by IL-4 but not by IL-13 are also well documented. Recent data suggest distinct roles for these two cytokines in the 'in vivo' pathology of airway inflammatory diseases such as asthma. In this study, we examined the possibility of differential signaling by IL-4 and IL-13 on cells of the airway, by comparing expression of receptor chains and activation of different Signal Transducer and Activator of Transcription (STAT) family members. Five primary cultured cell lines representing four non-immune human lung tissue cell types (smooth muscle, epithelium, endothelium, and fibroblast) were utilized. While we readily detected expression of IL-4 Ralpha and IL-13Ralpha1 in all five cell lines, gammaC was not detectable in any of these cell lines. Consistent with previous reports, we detected STAT-6 activation in all five airway tissue cell lines examined in response to both cytokines. In addition, we also consistently detected STAT-1 activation in all of these cells. This observation was extended to include lymphoid as well as myeloid cells that express also gammaC chain. In conclusion, while the study found no differences in STAT activation in response to the two cytokines, the data show that in addition to STAT-6 activation, STAT-1 activation is also a part of the integral signaling pathways utilized by IL-4 and IL-13.

Human pulmonary fibroblasts exhibit altered interleukin-4 and interleukin-13 receptor subunit expression in idiopathic interstitial pneumonia

Abnormal proliferation of pulmonary fibroblasts is a prominent feature of chronic pulmonary fibrotic diseases such as idiopathic interstitial pneumonia (IIP), but it is not presently clear how this proliferative response by lung fibroblasts can be therapeutically modulated. In the present study, we examined whether it was possible to selectively target primary human pulmonary fibroblasts grown out of surgical lung biopsies (SLBs) from IIP patients based on their expression of interleukin-4 receptor (IL-4R) and IL-13R subunits. Pulmonary fibroblast lines cultured from patients with the severest form of IIP, namely usual interstitial pneumonia, exhibited the greatest gene and protein expression of IL-4Ralpha, IL-13Ralpha1, and IL-13Ralpha2 compared with primary pulmonary fibroblast lines grown from other IIP SLBs and normal SLBs. When exposed to increasing concentrations of a chimeric protein comprised of human IL-13 and a truncated version of Pseudomonas exotoxin (IL13-PE), the proliferation of primary usual interstitial pneumonia fibroblasts was inhibited to a much greater extent compared with fibroblast lines from nonspecific interstitial pneumonia and respiratory bronchiolitis/interstitial lung disease patient groups. Fibroblasts from normal patients exhibited minimal susceptibility to the cytotoxic effect of IL13-PE. IL13-PE-mediated targeting of IIP fibroblasts was dependent on their expression of IL-4Ralpha and IL-13Ralpha2. Thus, these data suggest that the abnormal proliferative properties of human lung fibroblasts from certain IIP patient groups can be modulated in a manner that is dependent on the IL-4 and IL-13 receptor subunit expression by these cells.

IL-13 and IL-1beta promote lung fibroblast growth through coordinated up-regulation of PDGF-AA and PDGF-Ralpha

Peribronchiolar fibrosis is a prominent feature of airway remodeling in asthma and involves fibroblast growth and collagen deposition. Interleukin-13 (IL-13), a T-helper 2 cytokine, is a key mediator of airway remodeling in asthma, yet the mechanism through which IL-13 promotes fibroblast growth has not been investigated. In this study, we show that IL-13 stimulates the mitogenesis of mouse, rat, and human lung fibroblasts through release of a soluble mitogen that we identified as PDGF-AA. The IL-13-induced growth of human lung fibroblasts was attenuated by an anti-PDGF-AA neutralizing antibody, and IL-13 stimulated human lung fibroblasts to secrete PDGF-AA. Fibroblasts derived from mouse embryos possessing the lethal Patch mutation, which lack the PDGF-Ralpha, showed no mitogenic response to IL-13. However, Patch cells did exhibit IL-13-induced STAT-6 phosphorylation. Stable transfection of the PDGF-Ralpha into Patch cells restored the growth response to PDGF-AA and IL-13. Through the use of lung fibroblasts from STAT-6-deficient mice, we showed that IL-13-induced PDGF-AA release is STAT-6 dependent, but PDGF-AA-induced growth is STAT-6 independent. Finally, we showed that IL-1beta enhanced IL-13-induced mitogenesis of rat lung fibroblasts through up-regulation of the PDGF-Ralpha. Our findings indicate that IL-13 acts in synergy with IL-1beta to stimulate growth by coordinately up-regulating PDGF-AA and the PDGF-Ralpha, respectively.

Differential expression of interleukins IL-13 and IL-15 in normal ovarian tissue and ovarian carcinomas

OBJECTIVE

To determine the temporal and spatial expression of interleukins (IL)-13 and IL-15 in ovarian carcinoma compared to normal ovarian tissue.

METHODS

Quantitative RT-PCR, ELISA and immunohistochemistry.

RESULTS

Q-RT-PCR, ELISA and immunohistochemical analysis indicates that IL-13 and IL-15 mRNA and protein are expressed in normal ovary at various phases of the menstrual cycle with immunoreactive proteins detected in granulosa/theca and luteal cells and to a lesser extent in stromal cells and surface epithelial cells. Compared to normal ovary, ovarian carcinoma expresses elevated levels of IL-13 and IL-15 mRNA, with higher IL-13 expression in primary vs. metastatic tumors. IL-13 and IL-15 protein expression was also higher in the tumor tissues compared to ascites. In normal ovary, ovarian tumors and ascites, the ratio of IL-13/IL-15 favored IL-13. Immunoreactive IL-13 and IL-15 proteins were localized primarily in the tumor cells and infiltrated inflammatory cells with increased intensity with disease stage.

CONCLUSION

Normal ovary and ovarian tumors express IL-13 and IL-15 and pattern of their expression in carcinomas suggests that these cytokines may function in various ovarian cellular activities including inflammatory/immune responses that are integrated cellular events taking place in normal ovary and ovarian tumors.

Modulation of prostate cancer growth in bone microenvironments

Bone remains one of the major sites, and most lethal host organs, for prostate cancer metastasis. Prostate cell spread and establishment in bone depends on multiple reciprocal modifications of bone stromal and epithelial cancer cell behaviors. This review focuses on recent advances in the characterization of cell-cell and cell-matrix interplay, effects on cell growth, adhesion and invasion, and several therapeutic possibilities for co-targeting prostate cancer cells and bone stroma. We address the topic from three main perspectives: (1) the normal and aging bone stromal environment, (2) the "reactive" bone stromal environment, and (3) the cancerous prostate epithelial cells themselves. First, normal, and especially aging, bones provide uniquely rich and "fertile soil" for roaming cancer cells. The interactions between prostate cancer cells and insoluble extracellular matrices, soluble growth factors, and/or sex steroid hormones trigger bone remodeling, through increased osteoclastogenesis and furthur matrix metalloproteinase activity. Second, after cancer cell arrival and establishment in the bone, host stromal cells respond, becoming "reactive" in a process again involving extracellular matrix remodeling, together with growth factor and steroid receptor signaling this process ultimately enhances cancer cell migration, stromal transdifferentiation, and invasion of the cancer tissues by stromal, inflammatory, and immune-responsive cells. Third, prostate cancer cells also respond to supportive bone microenvironments, where soluble and matrix-associated molecules affect cancer cell growth and gene expression, especially altering cancer cell surface receptor and integrin-mediated cell signaling. We discuss both integrin cell-matrix and gap junctional cell-cell communication between cancer cells and their microenvironments during prostate cancer progression.

Expression of IL-2 receptor beta and gamma chains by human gingival fibroblasts and up-regulation of adhesion to neutrophils in response to IL-2

To investigate the role of human gingival fibroblasts (HGF), the major constituents of gingival tissue in periodontal inflammatory disease, the expression of interleukin-2 receptor (IL-2R) alpha, beta, and gamma chains was examined. Immunohistochemistry showed a pronounced accumulation of CD8(+) T cells in the inflamed lamina propria of gingival tissue from patients with adult periodontitis. HGF express IL-2Rbeta and IL-2Rgamma at mRNA and protein levels, but the expression of IL-2Ralpha could not be detected, as assessed by reverse transcriptase-polymerase chain reaction and flow cytometry. IL-2Rbeta, and -gamma expressed on HGF were functionally active, as addition of neutralizing anti-IL-2Rbeta and -gamma antibodies caused inhibition of the IL-2-induced production of monocyte chemoattractant protein-1 (MCP-1), and addition of IL-2 induced phosphorylation of Janus tyrosine kinase 3, which is critical in signaling through IL-2Rgamma in HGF. The IL-2-induced MCP-1 production was significantly inhibited by pretreatment with neutralizing antibody to IL-15. Addition of IL-2 also induced a marked up-regulation of the expression of intercellular adhesion molecule-1 (ICAM-1) on the surface of HGF, which in turn, significantly augmented the adhesion of human neutrophils, which were inhibited by an anti-ICAM-1 antibody. These results suggest that HGF express functional IL-2Rbetagamma, respond to IL-2 from infiltrated T cells, and actively participate in the inflammatory process in the periodontal region and that IL-15 produced by HGF sustains IL-2-mediated signaling in HGF.

Molecular mechanisms of interleukin-4-induced up-regulation of type I collagen gene expression in murine fibroblasts

OBJECTIVE

There is evidence that interleukin-4 (IL-4) plays a major role in the induction of extracellular matrix protein synthesis in fibrotic disease. We therefore examined the effect of IL-4 on collagen synthesis in primary fibroblasts isolated from normal and TSK/+ mice, which spontaneously develop a scleroderma-like syndrome characterized by diffuse cutaneous hyperplasia.

METHODS

Expression of the IL-4 receptor was determined by flow cytometry and Western blotting. The IL-4 signal transduction cascade was analyzed by Western blotting. We assessed the role of signal transducer and activator of transcription 6 (STAT-6) in IL-4 induction of alpha2(I) collagen promoter activity and message levels via luciferase reporter assay and real-time polymerase chain reaction. The activation status of the transcription factors activator protein 1 (AP-1) and Sp-1 upon stimulation with IL-4 in normal and TSK/+ fibroblasts was examined by electrophoretic mobility shift assay.

RESULTS

Flow cytometry and Western blotting showed that IL-4 receptor alpha expression was elevated in TSK/+ fibroblasts compared with normal fibroblasts. After IL-4 stimulation, janus-activated kinase 1 (JAK-1) and JAK-2 were phosphorylated to a greater degree in TSK/+ fibroblasts than in C57BL/6 fibroblasts. TSK/+ fibroblasts appeared to be hyperresponsive to IL-4, displaying increased synthesis of alpha1(I) collagen messenger RNA (mRNA), collagen protein, and activity of a luciferase reporter construct containing the -300 to +54 murine alpha2(I) collagen promoter. Overexpression of STAT-6 enhanced this effect, whereas expression of a dominant-negative STAT-6 abrogated the ability of IL-4 to induce alpha1(I) collagen mRNA in TSK/+ fibroblasts. Moreover, IL-4 induced increased DNA binding activity of transcription factors that are important for collagen synthesis.

CONCLUSION

Our observations indicate that IL-4 has a profound effect on several factors that have been identified as playing major roles in the regulation of collagen synthesis and suggest that IL-4 increases the expression of type I collagen through a mechanism involving the activation of transcription factors that bind to and activate collagen promoter.

Activation of Stat3 by receptor tyrosine kinases and cytokines regulates survival in human non-small cell carcinoma cells

Overexpression of receptor tyrosine kinases including the epidermal growth factor receptor (EGF-R) as well as nonreceptor tyrosine kinases, such as Src, have been implicated in the formation of human lung cancers. In addition, cytokines like interleukin-6 (IL-6) have been demonstrated to modulate lung cancer cell growth and elevated levels of IL-6 have been shown to be an adverse prognostic factor for patients with lung cancer. Despite a large body of evidence pointing to their potential importance, few direct studies into the role of signal transducers and activators of transcription (STAT) pathways in human lung cancer have been undertaken. Here we demonstrate that multiple nonsmall cell lung cancer cell lines demonstrate constitutive Stat3 DNA-binding activity. Stat3 DNA-binding activity is specifically upregulated by the addition of epidermal growth factor (EGF), IL-6, and hepatocyte-derived growth factor (HGF). Furthermore, the stimulation of Stat3 DNA-binding activity by EGF requires the activity of EGF-R tyrosine kinase as well as Src-kinase, while the upregulation of Stat3 activity by IL-6 or HGF requires only Src-kinase activity. Treatment of A549 lung cancer cells with PD180970 or SU6656, both pharmacological inhibitors of Src-kinase, resulted in reduced Src and Stat3 activity, cell cycle arrest in G2, and reduced viability of cells accompanied by induction of apoptosis. Treatment of Stat3-positive A549 and H358 cells with antisense Stat3 oligonucleotides results in complete loss of Stat3 DNA-binding activity and apoptosis, while Stat3-positive H1299 cells remained healthy. Finally, an adenoviral vector expressing a dominant-negative Stat3 isoform results in loss of Stat3 DNA-binding activity, apoptosis, and reduced cellular viability. These results demonstrate a role of Stat3 in transducing survival signals downstream of tyrosine kinases such as Src, EGF-R, and c-Met, as well as cytokines such as IL-6, in human nonsmall cell lung cancers.

Role of tissue stroma in cancer cell invasion

Maintenance of epithelial tissues needs the stroma. When the epithelium changes, the stroma inevitably follows. In cancer, changes in the stroma drive invasion and metastasis, the hallmarks of malignancy. Stromal changes at the invasion front include the appearance of myofibroblasts, cells sharing characteristics with fibroblasts and smooth muscle cells. The main precursors of myofibroblasts are fibroblasts. The transdifferentiation of fibroblasts into myofibroblasts is modulated by cancer cell-derived cytokines, such as transforming growth factor-beta (TGF-beta). TGF-beta causes cancer progression through paracrine and autocrine effects. Paracrine effects of TGF-beta implicate stimulation of angiogenesis, escape from immunosurveillance and recruitment of myofibroblasts. Autocrine effects of TGF-beta in cancer cells with a functional TGF-beta receptor complex may be caused by a convergence between TGF-beta signalling and beta-catenin or activating Ras mutations. Experimental and clinical observations indicate that myofibroblasts produce pro-invasive signals. Such signals may also be implicated in cancer pain. N-Cadherin and its soluble form act as invasion-promoters. N-Cadherin is expressed in invasive cancer cells and in host cells such as myofibroblasts, neurons, smooth muscle cells, and endothelial cells. N-Cadherin-dependent heterotypic contacts may promote matrix invasion, perineural invasion, muscular invasion, and transendothelial migration; the extracellular, the juxtamembrane and the beta-catenin binding domain of N-cadherin are implicated in positive invasion signalling pathways. A better understanding of stromal contributions to cancer progression will likely increase our awareness of the importance of the combinatorial signals that support and promote growth, dedifferentiation, invasion, and ectopic survival and eventually result in the identification of new therapeutics targeting the stroma.

Synergy between CD40 ligation and IL-4 on fibroblast proliferation involves IL-4 receptor signaling

Fibrosis can be an undesired consequence of activated cellular immune responses. The purpose of this work was to determine whether CD40 ligation and the pro-fibrotic cytokine IL-4 interact in regulating fibroblast proliferation and collagen production, and, if so, the mechanisms used. This study found that the combination of IL-4 and ligation of CD40 on the fibroblast cell surface had synergistic effects in stimulating fibroblast proliferation. In contrast, CD40 ligation negated the inhibitory effects of IFN-gamma on fibroblast proliferation. Western blotting analyses of fibroblast crude lysates revealed that a potential mechanism of the synergy between CD40 ligation and IL-4 was the phosphorylation of proteins at 130 kDa and, to a lesser degree, at 95, 85, and 75 kDa. Immunoprecipitation-Western blotting experiments showed that phosphorylation levels of IL-4Ralpha, Janus kinase 1, insulin receptor substrate 1, and insulin receptor substrate 2, factors with molecular mass close to the observed 130 kDa major phosphorylation band, increased in response to the combined CD40 ligation and IL-4 action. In contrast, there was no evidence that synergy was mediated by an increased expression of IL-4Ralpha chain, CD40, or the autocrine profibrotic cytokines IL-6 and TGF-beta. These findings suggest that CD40-CD40 ligand contacts between fibroblasts and cells secreting IL-4 may promote the profibrotic effects of IL-4 by affecting signal transduction and reducing the anti-fibrotic effects of IFN-gamma.

Novel anti-inflammatory effects of the inhaled corticosteroid fluticasone propionate during lung myofibroblastic differentiation

Asthma is characterized by an irreversible subepithelial fibrosis with the appearance of myofibroblasts, which can be now considered important early participants in inflammatory responses as well as potential targets for anti-inflammatory drugs. In this study, we show that fluticasone propionate (FP), a powerful inhaled corticosteroid (ICS), displays novel anti-inflammatory effects on human lung fibroblasts during their myofibroblastic differentiation. Indeed, FP inhibits in lung myofibroblasts, at a very early stage of differentiation, the activation of Janus kinase/STAT pathways induced by IL-13 (tyrosine kinase 2, STAT1, STAT3, STAT6, mitogen-activated protein kinase). Contrarily, in mildly or fully differentiated myofibroblastic cultures, FP still displays a potential anti-inflammatory activity even if it only inhibits tyrosine kinase 2 phosphorylation. Moreover, FP inhibits constitutive and TGF-beta-induced expression of alpha-smooth muscle actin, the main marker of myofibroblastic differentiation, both in very early and in mild differentiated myofibroblasts. Finally, FP displays an additional powerful anti-inflammatory effect, decreasing nuclear translocation of NF-kappaB independent of the degree of myofibroblastic differentiation. These data 1) suggest that myofibroblasts are priority targets for ICS, which is able to revert them to a normal phenotype even if they appear to be already engaged in their differentiation, and 2) may help to explain why asthma is improved by an early ICS treatment, whereas advanced asthma is more resistant to these drugs.