Inducible cyclooxygenase-2 (COX-2) has received much attention because of its role in neuro-inflammation and synaptic plasticity. Even though COX-2 levels are high in healthy animals, the function of this factor in adult neurogenesis has not been clearly demonstrated. Therefore, we performed the present study to compare the effects of pharmacological and genetic inhibition of COX-2 on adult hippocampal neurogenesis. Physiological saline or the same volume containing celecoxib was administered perorally every day for 5 weeks using a feeding needle. Compared to the control, pharmacological and genetic inhibition of COX-2 reduced the appearance of nestin-immunoreactive neural stem cells, Ki67-positive nuclei, and doublecortin-immunoreactive neuroblasts in the dentate gyrus. In addition, a decrease in phosphorylated cAMP response element binding protein (pCREB) at Ser133 was observed. Compared to pharmacological inhibition, genetic inhibition of COX-2 resulted in significant reduction of neural stem cells, cell proliferation, and neuroblast differentiation as well as pCREB levels. These results suggest that COX-2 is part of the molecular machinery that regulates neural stem cells, cell proliferation, and neuroblast differentiation during adult hippocampal neurogenesis via pCREB. Additionally, genetic inhibition of COX-2 strongly reduced neural stem cell populations, cell proliferation, and neuroblast differentiation in the dentate gyrus compared to pharmacological inhibition.
Animals ; Celecoxib/*pharmacology ; Cell Differentiation/drug effects/physiology ; Cell Proliferation/drug effects/physiology ; Cyclooxygenase 2/*genetics/metabolism ; Cyclooxygenase 2 Inhibitors/*pharmacology ; Dentate Gyrus/drug effects/*physiology ; Male ; Mice ; Mice, Knockout ; Neural Stem Cells/drug effects/physiology ; Neurogenesis/drug effects

BACKGROUNDMechanical stress plays an important role in the maintenance of bone homeostasis. Current hypotheses suggest that interstitial fluid flow is an important component of the system by which tissue level strains are amplified in bone. This study aimed to test the hypothesis that the short-term and appropriate fluid shear stress (FSS) is expected to promote the terminal differentiation of pre-osteoblasts and detect the expression profile of microRNAs in the FSS-induced osteogenic differentiation in MC3T3-E1 cells.

METHODSMC3T3-E1 cells were subjected to 1 hour of FSS at 12 dyn/cm(2) using a parallel plate flow system. After FSS treatment, cytoskeleton immunohistochemical staining and microRNAs (miRNAs) were detected immediately. Osteogenic gene expression and immunohistochemical staining for collagen type I were tested at the 24th hour after treatment, alkaline phosphatase (ALP) activity assay was performed at 24th, 48th, and 72 th hours after FSS treatment, and Alizarin Red Staining was checked at day 12.

RESULTSOne hour of FSS at 12 dyn/cm(2) induced actin stress fiber formation and rearrangement, up-regulated osteogenic gene expression, increased ALP activity, promoted synthesis and secretion of type I collagen, enhanced nodule formation, and promoted terminal differentiation in MC3T3-E1 cells. During osteogenic differentiation, expression levels of miR-20a, -21, -19b, -34a, -34c, -140, and -200b in FSS-induced cells were significantly down-regulated.

CONCLUSIONThe short-term and appropriate FSS is sufficient to promote terminal differentiation of pre-osteoblasts and a group of miRNAs may be involved in FSS-induced pre-osteoblast differentiation.

Actins ; chemistry ; Alkaline Phosphatase ; metabolism ; Animals ; Cell Differentiation ; Cells, Cultured ; Collagen Type I ; biosynthesis ; Core Binding Factor Alpha 1 Subunit ; genetics ; Cyclooxygenase 2 ; genetics ; Gene Expression Profiling ; Mice ; MicroRNAs ; physiology ; Osteoblasts ; cytology ; Osteogenesis ; Stress, Mechanical ; Stress, Physiological

Prebiotics modulate microbial composition and ensure a healthy gastrointestinal tract environment that can prevent colon cancer development. These natural dietary compounds are therefore potential chemopreventive agents. Thirty Sprague-Dawley rats (4 months old) were experimentally treated with procarcinogen dimethylhydrazine to induce colon cancer development. The rats were randomly assigned to three groups: a control group (CG), a group treated with dimethylhydrazine (DMH), and a group given DMH and inulin, a prebiotic (DMH+PRE). The effects of inulin on the activities of bacterial glycolytic enzymes, short-chain fatty acids, coliform and lactobacilli counts, cytokine levels, and cyclooxygenase-2 (COX-2) and transcription nuclear factor kappa beta (NFkappaB) immunoreactivity were measured. Inulin significantly decreased coliform counts (p < 0.01), increased lactobacilli counts (p < 0.001), and decreased the activity of beta-glucuronidase (p < 0.01). Butyric and propionic concentrations were decreased in the DMH group. Inulin increased its concentration that had been reduced by DMH. Inulin decreased the numbers of COX-2- and NFkappaB-positive cells in the tunica mucosae and tela submucosae of the colon. The expression of IL-2, TNFalpha, and IL-10 was also diminished. This 28-week study showed that dietary intake of inulin prevents preneoplastic changes and inflammation that promote colon cancer development.
Animals ; Bacterial Proteins/genetics/metabolism ; Colon/enzymology ; Colonic Neoplasms/chemically induced/*drug therapy/metabolism ; Colony Count, Microbial ; Cyclooxygenase 2/genetics/metabolism ; Cytokines/blood/genetics ; Diet ; Dietary Supplements/analysis ; Dimethylhydrazines/toxicity ; Enterobacteriaceae/drug effects/physiology ; Fatty Acids, Volatile/genetics/metabolism ; Female ; Gene Expression Regulation/drug effects ; Inulin/administration & dosage/*metabolism ; Lactobacillaceae/drug effects/physiology ; Male ; NF-kappa B/genetics/metabolism ; Prebiotics/*analysis ; Rats ; Rats, Sprague-Dawley

It has been proposed that the pro-inflammatory catalytic activity of cyclooxygenase-2 (COX-2) plays a key role in the aging process. However, it remains unclear whether the COX-2 activity is a causal factor for aging and whether COX-2 inhibitors could prevent aging. We here examined the effect of COX-2 inhibitors on aging in the intrinsic skin aging model of hairless mice. We observed that among two selective COX-2 inhibitors and one non-selective COX inhibitor studied, only NS-398 inhibited skin aging, while celecoxib and aspirin accelerated skin aging. In addition, NS-398 reduced the expression of p53 and p16, whereas celecoxib and aspirin enhanced their expression. We also found that the aging-modulating effect of the inhibitors is closely associated with the expression of type I procollagen and caveolin-1. These results suggest that pro-inflammatory catalytic activity of COX-2 is not a causal factor for aging at least in skin and that COX-2 inhibitors might modulate skin aging by regulating the expression of type I procollagen and caveolin-1.
Animals ; Aspirin/administration & dosage ; Catalysis ; Caveolin 1/genetics/metabolism ; Collagen Type I/genetics/metabolism ; *Cyclooxygenase 2/metabolism/physiology ; Cyclooxygenase 2 Inhibitors/*administration & dosage ; Gene Expression Regulation ; Mice ; Nitrobenzenes/*administration & dosage ; Pyrazoles/administration & dosage ; Skin Aging/*drug effects/physiology ; Sulfonamides/*administration & dosage ; Tumor Suppressor Protein p53/genetics/metabolism

OBJECTIVETo extract tumor interstitial fluid (TIF) from MKN-45 gastric cancer which is similar to "muddy phlegm" in Chinese medicine and observe influences of MKN-45 tumor interstitial fluid (MKN-45 TIF) intervention on metastasis of gastric cancer and on the expressions of vascular endothelial growth factor (VEGF), kinase insert domain containing receptor (KDR), epithelial-cadherin (E-cad), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1) and telomerase genes and proteins in primary tumor tissue.

METHODSAn MKN-45 tumor-bearing model was established in 50 nude mice. The modeled animals were equally randomized to 5 groups: the simple tumor-bearing group (model group), the normal saline (NS) via tail vein injection (i.v.) group (NS i.v. group), MKN-45 TIF i.v. group (TIF i.v. group), NS intraperitoneal injection (i.p.) group (NS i.p. group), and MKN-45 TIF i.p. group (TIF i.p. group). The TIF and NS intervention groups received injection (i.p. or i.v.) of MKN-45 TIF or NS twice a week, 0.2 mL at a time. After 8 weeks, the primary tumors were removed, weighed and HE stained to observe tumor metastasis. The primary tumor tissues were analyzed by immunohistochemistry and real-time quantitative PCR to detect expressions of VEGF, KDR, E-cad, COX-2, ICAM-1, and telomerase genes and proteins in different groups.

RESULTSThere were significant differences in tumor weight between TIF intervention groups and the model and NS intervention groups. Tumor metastasis was observed in all 5 groups, but the tumor metastasis rate in TIF intervention groups was significantly higher than those in the model and NS intervention groups. The gene and protein expressions of gastric cancer-related factors VEGF, KDR, COX-2, ICAM-1 and telomerase were unregulated while the gene and protein expressions of E-cad were downregulated in TIF intervention groups.

CONCLUSIONSTIF promotes tumor growth, invasion and metastasis of gastric cancer. These findings provide preliminary experimental clues for verifying the hypothesis of "tumor-phlegm microenvironment".

Animals ; Cadherins ; genetics ; metabolism ; Cell Line, Tumor ; Cyclooxygenase 2 ; genetics ; metabolism ; Extracellular Fluid ; metabolism ; Gene Expression Regulation, Neoplastic ; Humans ; Intercellular Adhesion Molecule-1 ; genetics ; metabolism ; Male ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Stomach Neoplasms ; metabolism ; secondary ; Telomerase ; genetics ; metabolism ; Tumor Microenvironment ; physiology ; Vascular Endothelial Growth Factor A ; genetics ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; genetics ; metabolism

Helicobacter pylori (H. pylori) is an important risk factor for chronic gastritis, peptic ulcer, and gastric cancer. Proteinase-activated receptor 2 (PAR2), subgroup of G-protein coupled receptor family, is highly expressed in gastric cancer, and chronic expression of cyclooxygenase-2 (COX-2) plays an important role in H. pylori-associated gastric carcinogenesis and inflammation. We previously demonstrated that H. pylori induced the expression of PAR2 and COX-2 in gastric epithelial cells. Present study aims to investigate whether COX-2 expression induced by H. pylori in Korean isolates is mediated by PAR2 via activation of Gi protein and Src kinase in gastric epithelial AGS cells. Results showed that H. pylori-induced COX-2 expression was inhibited in the cells transfected with antisense oligonucleotide for PAR2 or treated with Gi protein blocker pertussis toxin, Src kinase inhibitor herbimycin A and soybean trypsin inbitor, indicating that COX-2 expression is mediated by PAR2 through activation of Gi protein and Src kinase in gastric epithelial cells infected with H. pylori in Korean isolates. Thus, targeting the activation of PAR2 may be beneficial for prevention or treatment of gastric inflammation and carcinogenesis associated with H. pylori infection.
Benzoquinones/*pharmacology ; Cell Line, Tumor ; Cyclooxygenase 2/genetics/*metabolism ; Epithelial Cells/enzymology/metabolism/microbiology ; GTP-Binding Protein alpha Subunits, Gi-Go/metabolism ; Gastric Mucosa/enzymology/metabolism/*microbiology ; *Helicobacter pylori ; Humans ; Lactams, Macrocyclic/*pharmacology ; Oligonucleotides, Antisense ; Pertussis Toxin/*pharmacology ; RNA, Messenger/metabolism ; Receptor, PAR-2/*physiology ; src-Family Kinases/metabolism

Lining the inner surface of the walls of blood vessels, Endothelial cells (ECs) go beyond providing selective membrane to maintain the natural structure and function of vessels; they also synthesize varieties of vasoactive proteins to modify the pressure shift in the local flow field and hence they adapt the physiological activities of vessels. In this experiment, ELISA and RT-PCR technologies were adopted. We set up five different pressure loaded ECs groups,one non-activated cultured ECs group and one single shear stress loaded ECs group. Such a design was intended to demonstrate the effects of pressure shift on the expression of vasoactive protein synthesized by ECs [Endothelin-1(ET-1), endothelial Nitric Oxide Synthase (eNOS), Cyclooxygenase-2(COX-2) and Vascular Endothelial Growth Factor(VEGF)]. Our aim was to elucidate the mechanism of the pressure shift mediated dysfunction in ECs and the related dose-effect relationship. Based on these data, we suggest that ECs could modify the expression of vasoactive protein for adapting to the pressure shift in the local flow field; while in the process of--40 cmH2O induced ECs' dysfunction, the vasoactive proteins eNOS, COX-2 and VEGF play an important role in protecting ECs.
Cells, Cultured ; Cyclooxygenase 2 ; genetics ; metabolism ; Endothelial Cells ; metabolism ; physiology ; Endothelin-1 ; genetics ; metabolism ; Humans ; Nitric Oxide Synthase Type III ; genetics ; metabolism ; Pressure ; RNA, Messenger ; genetics ; metabolism ; Vascular Endothelial Growth Factor A ; genetics ; metabolism

BACKGROUNDEstrogen receptor (ER)-negative breast cancer cells are more aggressive than ER-positive cells. Elevated levels of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-C (VEGF-C) expression have been detected in cultured human breast cancer cells and are associated with negative hormone receptor status. In this study, we created ERalpha stable transfectants in MDA-MB-231 cells to explore the effect of ERalpha on cell growth and COX-2 and VEGF-C expression.

METHODSThe green fluorescent protein (GFP)-ERalpha plasmids were stably transfected into ER-negative MDA-MB-231 cells. The proliferation and migration of untransfected MDA-MB-231 cells, ERalpha-transfected MDA-MB-231 cells and ER-positive MCF-7 cells were determined. The expression of COX-2, and the levels of VEGF-C mRNA and the VEGF-C secretion concentration were assayed in these cell lines.

RESULTSThe proliferation and migration capacities of ERalpha-tranfected MDA-MB-231 cells were significantly decreased (P < 0.05). The expression of COX-2 was significantly lower in ERalpha-tranfected MDA-MB-231 cells than in untranfected MDA-MB-231 cells. The mRNA and protein levels of VEGF-C were lower in ERalpha-tranfected MDA-MB-231 cells than in untransfected MDA-MB-231 cells (P < 0.05).

CONCLUSIONSERalpha stable transfection inhibits proliferation and migration capacities of MDA-MB-231 cells and decreases expression of COX-2 and VEGF-C. The decreases of proliferation and migration capacities may be related to suppression of COX-2 and VEGF-C expression.

Blotting, Western ; Breast Neoplasms ; genetics ; metabolism ; Cell Cycle ; genetics ; physiology ; Cell Line, Tumor ; Cell Movement ; genetics ; physiology ; Cell Proliferation ; Cyclooxygenase 2 ; genetics ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Estrogen Receptor alpha ; genetics ; metabolism ; Female ; Flow Cytometry ; Humans ; Polymerase Chain Reaction ; Transfection ; Vascular Endothelial Growth Factor C ; genetics ; metabolism

BACKGROUNDExperimental evidence indicates that cyclooxygenase-2 (COX-2) plays a critical role in blastocyst implantation; however, little is known of the role of COX-2 in unexplained recurrent spontaneous abortion (URSA).

METHODSWe evaluated the expression level and potential signaling pathway of COX-2 in 30 cases of URSA who were excluded the abnormality of chromosomes, anatomy, endocrine, infectious, autoimmune diseases and in 30 normal pregnancies.

RESULTSThe mRNA and the protein expression level of COX-2 in the URSA group (-0.238 +/- 0.848, 0.368 +/- 0.089, respectively) were significantly lower than that in the control group (1.943 +/- 3.845, 1.046 +/- 0.108, respectively) (both, P < 0.01). The expression of prostaglandins PGF(2a), PGD(2), PGE(2), and PGI(2), in the URSA group ((2326.0 +/- 295.6) pg/ml, (2164.0 +/- 240.5) pg/ml, (238.7 +/- 26.4) pg/ml, (2337.0 +/- 263.0) pg/ml, respectively) were significantly lower than that in the control group ((3450.0 +/- 421.7) pg/ml, (3174.0 +/- 415.6) pg/ml, (323.5 +/- 43.8) pg/ml, (3623.0 +/- 460.4) pg/ml, respectively) (P < 0.05). The mRNA expression level of PPARbeta and RXRalpha (0.859 +/- 0.653, -0.172 +/- 0.752, respectively) in URSA group was significantly lower than that in the control group (1.554 +/- 1.735, 0.777 +/- 2.482, respectively) (both P< 0.05). The mRNA and protein expression levels of vascular endothelial growth factor-A (VEGF-A) in the URSA group (2.010 +/- 1.522, 0.35 +/- 0.46) was significantly lower than that in the control group (4.569 +/- 2.430, 0.750 +/- 0.350) (both P < 0.05).

CONCLUSIONSCOX-2 and the COX-2-derived PGI(2) signaling pathway possibly play an important role in successful embryo implantation, and their decreased expression may result in URSA. The decreased expression may influence the expression of VEGF-A which interferes with placental angiogenesis causing failure of embryo implantation, leading to spontaneous abortion.

Abortion, Habitual ; enzymology ; genetics ; Adult ; Blotting, Western ; Cyclooxygenase 2 ; genetics ; metabolism ; Dinoprost ; metabolism ; Dinoprostone ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Epoprostenol ; metabolism ; Female ; Humans ; Polymerase Chain Reaction ; Pregnancy ; Prostaglandin D2 ; metabolism ; Signal Transduction ; genetics ; physiology ; Vascular Endothelial Growth Factor A ; metabolism

PURPOSE: Down-regulation of E-cadherin is a hallmark of the epithelial-to-mesenchymal transition (EMT). EMT progression in cancer cells is associated with the loss of certain epithelial markers and the acquisition of a mesenchymal phenotype, as well as migratory activities. Cyclooxygenase-2 (COX-2) expression is associated with tumor invasion and metastasis in colon cancer. This study investigated the relationship between E-cadherin and COX-2 in colon cancer cells and human colon tumors. MATERIALS AND METHODS: Colon cancer cell lines and immunohistochemistry were used. RESULTS: E-cadherin expression was inversely related to the expressions of COX-2 and Snail in colon cancer cells. Ectopic expression of COX-2 or Snail reduced E-cadherin and induced a scattered, flattened phenotype with few intercellular contacts in colon cancer cells. Treatment of cancer cells with phorbol 12-myristate 13-acetate increased the expressions of COX-2 and Snail, decreased 15-hydroxyprostaglandin dehydrogenase expression, and increased the cells' motility. In addition, exposure to prostaglandin E2 increased Snail expression and cell motility, and decreased E-cadherin expression. Membranous E-cadherin expression was lower in adenomas and cancers than in the adjacent, non-neoplastic epithelium. In contrast, the expressions of Snail and COX-2 were higher in cancers than in normal tissues and adenomas. The expressions of COX-2 and Snail increased in areas with abnormal E-cadherin expression. Moreover, COX-2 expression was related to higher tumor stages and was significantly higher in nodal metastatic lesions than primary cancers. CONCLUSION: This study suggests that COX-2 may have a role in tumor metastasis via EMT.
Adult ; Aged ; Aged, 80 and over ; Blotting, Western ; Cadherins/genetics/metabolism ; Cell Differentiation/genetics/physiology ; Cell Line, Tumor ; Cell Movement/drug effects/genetics ; Colonic Neoplasms/*metabolism/*pathology ; Cyclooxygenase 2/genetics/metabolism/*physiology ; Dinoprostone/pharmacology ; Epithelial Cells/*cytology/metabolism ; Epithelium/*metabolism ; Female ; HT29 Cells ; Homeodomain Proteins/genetics/metabolism ; Humans ; Immunohistochemistry ; Male ; Mesoderm/*cytology/*metabolism ; Middle Aged ; Reverse Transcriptase Polymerase Chain Reaction ; Tetradecanoylphorbol Acetate/pharmacology ; Transcription Factors/genetics/metabolism