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Y Uenoyama,
H Seno,
A Fukuda,
A Sekikawa,
A Nanakin,
T Sawabu,
M Kawada,
N Kanda,
K Suzuki,
N Yada,
H Fukui,
T Chiba
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ABSTRACT: Cyclooxygenase-2 (COX-2) plays important roles in tumor development. Especially in the early-stage colorectal tumors, COX-2 expression is often observed in the tumor stroma. However, the mechanism regulating such stromal expression of COX-2 remains unknown. In the present study, we simulated the indirect interaction between epithelial cells and stromal cells in the process of colorectal tumor development using an in vitro co-culture model in which NIH3T3 fibroblasts were co-cultured with 'sparsely' or 'densely' populated intestinal epithelial cells, Intestine-407 as a model of premalignant or benign intestinal epithelial cells, and DLD-1 and Caco-2 as models of malignant epithelial cells. COX-2 expression in NIH3T3 fibroblasts was upregulated when co-cultured with the 'dense' epithelial cells regardless of their character. Interestingly, there was pericellular hypoxia in the vicinity of NIH3T3 fibroblasts when co-cultured with 'dense' epithelial cells, and the recovery of the partial pressure of oxygen level resulted in the reduction of enhanced COX-2 expression only in NIH3T3 fibroblasts co-cultured with 'dense' Intestine-407 cells. Furthermore, COX-2 expression was also reduced by the inhibition of transcription factor AP-1. Thus, pericellular hypoxia of the stromal cells caused by densely populated epithelial cells may be one of the potent COX-2 enhancers before completion of malignant transformation during intestinal tumor development.
Oncogene 07/2006; 25(23):3277-85. · 6.37 Impact Factor
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A Sekikawa,
H Fukui,
S Fujii,
A Nanakin,
N Kanda, Y Uenoyama,
T Sawabu,
H Hisatsune,
T Kusaka,
S Ueno,
H Nakase,
H Seno,
T Fujimori,
T Chiba
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ABSTRACT: Although regenerating gene (REG) Ialpha protein may be involved in the inflammation and carcinogenesis in the gastrointestinal tract, its pathophysiological role in ulcerative colitis (UC) and the resulting colitic cancer remains unclear. We investigated expression of the REG Ialpha gene and its protein in UC and colitic cancer tissues. We examined whether cytokines are responsible for REG Ialpha gene expression and whether REG Ialpha protein has a trophic and/or an antiapoptotic effect on colon cancer cells.
Expression of REG Ialpha mRNA and its gene product in UC tissues was analysed by real time reverse transcription-polymerase chain reaction and immunohistochemistry, respectively. The effects of cytokines on REG Ialpha promoter activity were examined in LoVo cells by luciferase reporter assay. The effects of REG Ialpha protein on growth and H(2)O(2) induced apoptosis were examined in LoVo cells by MTT and TUNEL assays, respectively.
REG Ialpha protein was strongly expressed in inflamed epithelium and in dysplasias and cancerous lesions in UC tissues. The level of REG Ialpha mRNA expression in UC tissues correlated significantly with severity of inflammation and disease duration. REG Ialpha promoter activity was enhanced by stimulation with interferon gamma or interleukin 6. REG Ialpha protein promoted cell growth and conferred resistance to H(2)O(2) induced apoptosis in LoVo cells. REG Ialpha protein promoted Akt phosphorylation and enhanced Bcl-xL and Bcl-2 expression in LoVo cells.
The REG Ialpha gene is inducible by cytokines and its gene product may function as a mitogenic and/or an antiapoptotic factor in the UC-colitic cancer sequence.
Gut 11/2005; 54(10):1437-44. · 10.11 Impact Factor
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ABSTRACT: We studied the effect of dibutyryl cyclic adenosine-3',5'-monophosphate (dbcAMP) and several cytokines on the expression of IgG Fc receptor subclasses (Fc gamma RI, Fc gamma RII, and Fc gamma RIII) and low-affinity IgE Fc receptors (Fc epsilon RII/CD23) on peripheral eosinophils and on eosinophils differentiated in vitro from cord blood mononuclear cells by interleukin 5 (IL-5). These eosinophils expressed Fc gamma RII, and few, if any, Fc gamma RI and Fc gamma RIII as determined by flow cytometry with specific monoclonal antibodies. dbcAMP enhanced the Fc gamma RII expression, but did not induce the Fc gamma RI and Fc gamma RIII expression. Interferon-gamma (IFN-gamma) enhanced Fc gamma RII expression at the same degree as did dbcAMP. IFN-gamma also induced Fc gamma RIII expression on peripheral eosinophils but not on eosinophils grown in the presence of IL-5. Eosinophils grown in the presence of IL-5 showed a relatively immature phenotype, determined by electron microscopy and the low content of eosinophil cationic protein. Contrary to its enhancing effect on Fc gamma RII expression, dbcAMP suppressed the IFN-gamma-induced Fc gamma RIII expression on peripheral eosinophils. Other cytokines examined did not show any effects on Fc gamma R expression. Fc epsilon RII/CD23 expression was neither detected nor induced. These results indicate that expression of Fc gamma RII and Fc gamma RIII on eosinophils is regulated differently and that cAMP and IFN-gamma play important roles in the regulation of Fc gamma R expression.
Hematologic pathology 02/1994; 8(3):85-97.
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ABSTRACT: The inhibitory effects of azelastine hydrochloride on PAF-induced and fMLP-induced Ca2+ influx, actin polymerization and calcium ionophore A23187-induced and aggregated IgG-induced release of eosinophil cationic protein (ECP) of an eosinophilic leukaemia cell line, EoL-1, were examined. EoL-1 cells cultured with 0.2 mM dibutyryladenosine-cyclic monophosphate for 48 hours showed an increase in intracellular free Ca2+ concentration ([Ca2+]i) and actin polymerization when stimulated by PAF and fMLP. Azelastine hydrochloride inhibited PAF-induced and fMLP-induced Ca2+ influx ([Ca2+]i) in a dose-dependent manner with an IC50 of 1 x 10(-8) M and 1 x 10(-7) M, respectively. It also inhibited PAF-induced and fMLP-induced actin polymerization in a dose-dependent manner up to 40% and 30%, respectively. EoL-1 cells were differentiated to contain ECP in their eosinophilic granules when cultured for 9 days with supernatants of a human adult T cell leukaemia cell line, HIL-3 (HIL-3 sup). Calcium ionophore A23187 and aggregated IgG induced the secretion of ECP by EoL-1 cells. Azelastine hydrochloride inhibited the secretion of ECP in a dose-dependent manner. These inhibitory effects were seen even at therapeutic concentrations of 10(-8) M to 10(-9) M. These results indicate that the therapeutic effects of azelastine hydrochloride as an anti-allergic agent may include inhibition of the accumulation of eosinophils into the locus of allergic inflammation and of the release of cytotoxic granules from eosinophils.
Current Medical Research and Opinion 02/1993; 13(3):163-74. · 2.38 Impact Factor
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ABSTRACT: We investigated actin polymerization and the increase of cytosolic free calcium concentration ([Ca2+]i) in a human eosinophilic leukemia cell line, EoL-1, in response to stimulation with chemotactic factors; we also investigated the effect of dibutyryl cyclic AMP (dbcAMP) on the responses. EoL-1 cells under normal culture conditions did not show either actin polymerization or an increase in [Ca2+]i when stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP). Expression of formyl peptide receptors was not detectable on untreated EoL-1 cells, either. Dibutyryl cAMP induced the expression of formyl peptide receptors and the responsiveness to fMLP. The responsiveness of EoL-1 cells to the complement fragment C5a and platelet-activating factor (PAF) was also induced or enhanced by dbcAMP. The growth of EoL-1 cells was decreased and the proportion of cells in the G0/G1 phase of the cell cycle was increased by the treatment of EoL-1 cells with dbcAMP. The proportion of eosinophilic granule-containing cells and the content of eosinophil cationic protein (ECP) in EoL-1 cells was also increased when they were stimulated with dbcAMP for a longer period. The responsiveness of EoL-1 cells to fMLP, C5a, and PAF was shown to be regulated independently. EoL-1 cells and dbcAMP seem to be useful for examining chemotactic receptor expression and its signal transduction mechanisms.
Experimental Hematology 10/1991; 19(8):823-8. · 2.90 Impact Factor
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ABSTRACT: We investigated the positive and negative effects of IFN-gamma, PMA, dibutyryl cAMP (Bt2cAMP), dexamethasone and transforming growth factor-beta (TGF-beta) on Fc gamma R subtype expression and phagocytosis of a human monoblast cell line, U937. IFN-gamma increased and Bt2cAMP decreased Fc gamma RI expression determined by a mAb 32.2, whereas PMA and Bt2cAMP increased Fc gamma RII expression determined by a mAb IV-3. Phagocytosis was measured microscopically by counting ingested aggregated human IgG- or BSA-treated ox E (Eo'-IgG or Eo'-BSA). IFN-gamma increased the phagocytosis of Eo'-IgG but not that of Eo'-BSA, and PMA increased the phagocytosis of both Eo'-IgG and Eo'-BSA. Bt2cAMP decreased both basal and IFN-gamma- and PMA-augmented phagocytosis of U937 cells. Dexamethasone also inhibited both basal and IFN-gamma-augmented Fc gamma RI expression and PMA-augmented Fc gamma RII expression and phagocytosis, but did not affect IFN-gamma-augmented phagocytosis of Eo'-IgG. The augmentation of phagocytosis of Eo'-IgG by IFN-gamma thus seems to be due mainly to the increased internalizing process rather than to increased Fc gamma RI expression. TGF-beta slightly decreased Fc gamma R expression. In a study of the participation of protein kinase C (PK-C), it was found that H-7, a PK-C inhibitor, did not inhibit either IFN-gamma- or PMA-enhanced Fc gamma RI and Fc gamma RII expression, respectively, and 1-oleoyl-2-acetylglycerol and N-(6-phenylhexyl)-5-chloro-1-naphthalenesulfonamide, both PK-C activators, did not show any apparent increase in Fc gamma R expression and phagocytosis. These results show that Fc gamma RI and Fc gamma RII expression on U937 cells is regulated by different mechanisms and that IFN-gamma and PMA play their roles in Fc gamma R expression and phagocytosis by different pathways. It is possible that cAMP but not PK-C plays an important role in the regulation of Fc gamma R expression and phagocytosis.
The Journal of Immunology 01/1990; 143(12):4158-65. · 5.79 Impact Factor
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ABSTRACT: The relationship of cord serum sFc epsilon R2 levels to the development of atopic symptoms in early childhood was studied. Cord sFc epsilon R2 was 444.2 +/- 235.1 pg/ml (n = 77), which was not significantly different from maternal serum sFc epsilon R2 (541.7 +/- 346.9 pg/ml, n = 42). However, there was no correlation between cord and maternal serum sFc epsilon R2, suggesting that most, if not all, of cord serum sFc epsilon R2 was produced by the fetus itself. Cord serum sFc epsilon R2 in infants who developed atopic symptoms later was significantly higher than that in infants who were free of atopic symptoms (P less than 0.01 at 7 and 13 months of age). The incidence of the development of atopic symptoms increased with the increase of cord serum sFc epsilon R2. These results suggest that sFc epsilon R2 is related to the development of atopic disorders and that the measurement of cord serum sFc epsilon R2 may be of value in predicting the development of atopic disorders in early childhood.
Immunology Letters 24(1):63-7. · 2.53 Impact Factor
