PKA phosphorylates multiple molecules involved in calcium (Ca 2+ ) handling in cardiac myocytes and is considered to be the predominant regulator of β-adrenergic receptor-mediated enhancement of cardiac contractility; however, recent identification of exchange protein activated by cAMP (EPAC), which is independently activated by cAMP, has challenged this paradigm. Mice lacking Epac1 (Epac1 KO) exhibited decreased cardiac contractility with reduced phospholamban (PLN) phosphorylation at serine-16, the major PKA-mediated phosphorylation site. In Epac1 KO mice, intracellular Ca 2+ storage and the magnitude of Ca 2+ movement were decreased; however, PKA expression remained unchanged, and activation of PKA with isoproterenol improved cardiac contractility. In contrast, direct activation of EPAC in cardiomyocytes led to increased PLN phosphorylation at serine-16, which was dependent on PLC and PKCε. Importantly, Epac1 deletion protected the heart from various stresses, while Epac2 deletion was not protective. Compared with WT mice, aortic banding induced a similar degree of cardiac hypertrophy in Epac1 KO; however, lack of Epac1 prevented subsequent cardiac dysfunction as a result of decreased cardiac myocyte apoptosis and fibrosis. Similarly, Epac1 KO animals showed resistance to isoproterenol-and aging-induced cardiomyopathy and attenuation of arrhythmogenic activity. These data support Epac1 as an important regulator of PKA-independent PLN phosphorylation and indicate that Epac1 regulates cardiac responsiveness to various stresses.

Allergic contact hypersensitivity to metals is a delayed-type allergy. Although various metals are known to produce an allergic reaction, nickel is the most frequent cause of metal allergy. Researchers have attempted to elucidate the mechanisms of metal allergy using animal models and human patients. Here, the immunological and molecular mechanisms of metal allergy are described based on the findings of previous studies, including those that were recently published. In addition, the adsorption and excretion of various metals, in particular nickel, is discussed to further understand the pathogenesis of metal allergy.

Regulatory T (Treg) cells play key roles in various immune responses. For example, Treg cells contribute to the complex pathogenesis of inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis during onset or development of that disease. Many animal models of IBD have been used to investigate factors such as pathogenic cytokines, pathogenic bacteria, and T-cell functions, including those of Treg cells. In addition, analyses of patients with IBD facilitate our understanding of the precise mechanism of IBD. This review article focuses on the role of Treg cells and outlines the pathogenesis and therapeutic strategies of IBD based on previous reports.

Adenylyl cyclase, a major target enzyme of ␤-adrenergic receptor signals, is potently and directly inhibited by P-site inhibitors, classic inhibitors of this enzyme, when the enzyme catalytic activity is high. Unlike ␤-adrenergic receptor antagonists, this is a non-or uncompetitive inhibition with respect to ATP. We have examined whether we can utilize this enzymatic property to regulate the effects of ␤-adrenergic receptor stimulation differentially. After screening multiple new and classic compounds, we found that some compounds, including 1R,4R-3-(6-aminopurin-9-yl)-cyclopentanecarboxylic acid hydroxyamide, potently inhibited type 5 adenylyl cyclase, the major cardiac isoform, but not other isoforms. In normal mouse cardiac myocytes, contraction induced by low ␤-adrenergic receptor stimulation was poorly inhibited with this compound, but the induction of cardiac myocyte apoptosis by high ␤-adrenergic receptor stimulation was effectively prevented by type 5 adenylyl cyclase inhibitors. In contrast, when cardiac myocytes from type 5 adenylyl cyclase knock-out mice were examined, ␤-adrenergic stimulation poorly induced apoptosis. Our data suggest that the inhibition of ␤-adrenergic signaling at the level of the type 5 adenylyl cyclase isoform by P-site inhibitors may serve as an effective method to prevent cardiac myocyte apoptosis induced by excessive ␤-adrenergic stimulation without deleterious effect on cardiac myocyte contraction.Adrenergic stimulation via the sympathetic nervous system is a major mechanism to regulate cardiac function (1). Norepinephrine released from the synaptic terminal binds to ␤-adrenergic receptors (␤-AR), 1 leading to the activation of adenylyl cyclase (AC) and thus the production of cAMP, which initiates a cascade of protein phosphorylation and regulation of many key signaling elements involved in muscle contraction and calcium handling. The immediate outcome of this stimulation is increased cardiac contractility and output. Pharmacological inhibition of this pathway, by the use of ␤-AR antagonists, has been widely utilized to attenuate cardiac function in the clinical setting of treating high blood pressure for several decades. Recently, ␤-AR antagonists have been used in the treatment of heart failure, i.e. in hearts with deteriorated cardiac function. This paradoxical usage of ␤-AR antagonists in heart failure has been rationalized by the protection of the heart from excessive sympathetic stimulation. Under this pathological condition, it is well known that the sympathetic activity is increased markedly (2-4), leading to the remodeling of the heart (5) and, more importantly, the induction of cardiac myocyte apoptosis, as demonstrated by both in vivo and in vitro studies (6, 7). However, a major problem in introducing ␤-AR antagonist therapy is the worsening of cardiac function (8).It is believed that regulating ␤-adrenergic signaling at the level of AC, instead of the receptor, may serve as an alternative to the common ␤-AR regulating therapy, which is most exemplified by direct ...

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Purpose: Head and neck squamous cell carcinoma (HNSCC) shows persistent invasion that frequently leads to local recurrence and distant lymphatic metastasis. However, molecular mechanisms associated with invasion of HNSCC remain poorly understood. We identified IFNinduced transmembrane protein 1 (IFITM1) as a candidate gene for promoting the invasion of HNSCC by comparing the gene expression profiles between parent and a highly invasive clone. Therefore, we examined the role of IFITM1in the invasion of HNSCC. Experimental Design: IFITM1 expression was examined in HNSCC cell lines and cases by reverse transcription^PCR and immunohistochemistry. IFITM1 overexpressing and knockdown cells were generated, and the invasiveness of these cells was examined by in vitro invasion assay. Gene expression profiling of HNSCC cells overexpressing IFITM1versus control cells was examined by microarray. Results: HNSCC cells expressed IFITM1mRNA at higher levels, whereas normal cells did not. By immunohistochemistry, IFITM1 expression was observed in early invasive HNSCC and invasive HNSCC. Interestingly, IFITM1 was expressed at the invasive front of early invasive HNSCC, and higher expression of IFITM1 was found in invasive HNSCC. In fact, IFITM1 overexpression promoted and IFITM1knockdown suppressed the invasion of HNSCC cells in vitro. Gene expression profiling of HNSCC cells overexpressing IFITM1 versus control cells revealed that several genes, including matrix metalloproteinase, were up-regulated in IFITM1overexpressing cells. Conclusion: Our findings suggest that IFITM1plays an important role for the invasion at the early stage of HNSCC progression and that IFITM1can be a therapeutic target for HNSCC.Head and neck squamous cell carcinoma (HNSCC) is one of the most common types of human cancer, with an annual incidence of >500,000 cases worldwide (1). The extent of lymph node metastasis is a major determinant in the prognosis of HNSCC. Like most epithelial cancers, HNSCC develops through the accumulation of multiple genetic and epigenetic alterations in a multistep process (2). Recent molecular studies have advanced our understanding of the disease and provided a rationale to develop novel strategies for early detection, classification, prevention, and treatment. Attempts to identify the genes involved in the metastasis are pivotal for the early prediction of HNSCC behavior. The process of metastasis consists of sequential and selective steps, including proliferation, induction of angiogenesis, detachment, motility, invasion into circulation, aggregation and survival in the circulation, cell arrest in distant capillary beds, and extravasation into organ parenchyma (2). We previously established an HNSCC cell line, MSCC-1, from lymph node metastasis (3). Moreover, we isolated a highly invasive clone MSCC-Inv1 from MSCC-1 cells by using an in vitro invasion assay device (4). Then, we compared the transcriptional profile of parent cells (MSCC-1) and a highly invasive clone (MSCC-Inv1) by microarray analysis to identify g...

Background:Angiogenesis is an important step in the metastatic cascade of tumors. Results: MMP-13 itself as well as VEGF-A secretion from fibroblasts promotes angiogenesis. Indeed, MMP-13 is well correlated with blood vessel density in human cancer tissues. Conclusion: MMP-13 can be a marker for prediction of malignant behaviors and a therapeutic target in cancer. Significance: This work provides new insights regarding the role of MMP-13 in tumor angiogenesis.

Background:Epithelial–mesenchymal transition (EMT) is a crucial process in cancer progression that provides cancer cells with the ability to escape from the primary focus, invade stromal tissues and migrate to distant regions. Cell lines that lack E-cadherin show increased tumorigenesis and metastasis, and the expression levels of E-cadherin and Snail correlate inversely with the prognosis of patients suffering from breast cancer or oral squamous cell carcinoma (OSCC). Moreover, recent studies have shown that most EMT cases are regulated by soluble growth factors or cytokines. Among these factors, fibroblast growth factors (FGFs) execute diverse functions by binding to and activating members of the FGF receptor (FGFR) family, including FGFR1–4. Fibroblast growth factor receptor 1 is an oncoprotein that is involved in tumorigenesis, and PD173074 is known to be a selective inhibitor of FGFR1. However, the roles of FGFR1 and FGFR1 inhibitors have not yet been examined in detail.Methods:Here, we investigated the expression of FGFR1 in head and neck squamous cell carcinoma (HNSCC) and the role of the FGFR1 inhibitor PD173074 in carcinogenesis and the EMT process.Results:Fibroblast growth factor receptor 1 was highly expressed in 54% of HNSCC cases and was significantly correlated with malignant behaviours. Nuclear FGFR1 expression was also observed and correlated well with histological differentiation, the pattern of invasion and abundant nuclear polymorphism. Fibroblast growth factor receptor 1 was also overexpressed in EMT cell lines compared with non-EMT cell lines. Furthermore, treatment of HOC313 cells with PD173074 suppressed cellular proliferation and invasion and reduced ERK1/2 and p38 activation. These cells also demonstrated morphological changes, transforming from spindle- to cobble stone-like in shape. In addition, the expression levels of certain matrix metalloproteinases (MMPs), whose genes contain activator protein-1 (AP-1) promoter sites, as well as Snail1 and Snail2 were reduced following PD173074 treatment.Conclusion:Taken together, these data suggest that PD173074 inhibits the MAPK pathway, which regulates the activity of AP-1 and induces MET. Furthermore, this induction of MET likely suppresses cancer cell growth and invasion.