Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cytosolic phospholipase A2 (cPLA2), cyclooxygenase (COX)-1 and COX-2 play important and integrated roles in the release and subsequent metabolism of arachidonic acid, an important second messenger, in brain and other tissues. Antibodies to each of these enzymes were used to examine their cellular localization and expression in the cerebellum of the adult macaque, using Western blotting and immunohistochemical methods. COX-2 and cPLA2 immunoreactivities co-localized on the plasma membrane of Purkinje cells, and within punctate intracellular regions. In contrast, COX-1 immunoreactivity was relatively uniform in Purkinje cell cytoplasm, and was more homogeneous in cells of the granular cell layer and occasionally of the molecular layer. COX-1 immunoreactivity was not found on the cell surface. Labeling of Purkinje cell dendrites was not marked for any of the enzymes. cPLA2 and COX-2 have been shown to be functionally coupled in a number of cell systems, and in brain following lithium chloride administration to rats. The co-localization of cPLA2 and COX-2 is consistent with evidence of their functional coupling at brain synapses, and of the presence of an unesterified brain arachidonate pool released by cPLA2 which is the precursor for prostaglandin formation via COX-2.
Brain Res Mol Brain Res 2003 Aug 19
PMID:Co-localization of cytosolic phospholipase A2 and cyclooxygenase-2 in Rhesus monkey cerebellum. 1294 66

The aims of this study were to examine the overexpression of COX-2 protein and its relationship to apoptosis in cervical carcinoma patients treated with neoadjuvant chemo-therapy (NAC), and to assess the potential role of COX-2 as a predictor of the response to NAC in a series of patients with cervical carcinoma. For immunohistochemical analysis, cervical cancer tissue samples were collected before NAC and 3 weeks after NAC using transcatheter arterial infusion of cisplatin from 40 patients who underwent surgery for advanced cervical carcinoma in stages IB, IIA and IIB and from 5 normal cervical tissues between 1991 and 2000 at the Department of Obstetrics and Gynecology, under informed consent. Patients were randomly assigned to receive one or two arterial infusions of cisplatin. COX-2 protein expression was detected by immunohistochemical staining and was classified as no expression for tumors with negative or <10%, while > or =10% positive staining was defined as overexpression. Detection of apoptosis was done by the TUNEL method. The percentage of cells with DNA fragmentation (apoptotic index, AI) was calculated before NAC and 3 weeks after NAC. The AI ratio (AI after NAC/AI before NAC) was also calculated. COX-2 expression was not detected in the normal cervix. Overexpression of COX-2 protein was detected in 18 out of 40 (45.0%) cervical cancers. A higher incidence of COX-2 protein overexpression was observed in patients with adenocarcinoma than in those with squamous cell carcinoma (p=0.1797, Fisher's exact text). The average AI value before and after NAC was 8.85 versus 11.82 respectively. In COX-2 protein-negative patients with squamous cell carcinoma, the AI ratio was 0.96+/-0.46 following one arterial infusion of cisplatin and 3.19+/-2.72 following two infusions of cisplatin. There was a significant positive correlation between apoptosis and the number of infusions of cisplatin (p=0.0098, Mann-Whitney, U-test). Our findings suggest that COX-2 protein expression could be used as a predictor of chemoresistance and that assessment of the COX-2 status could be useful to identify cervical cancer patients who may benefit from NAC.
Int J Mol Med 2003 Nov
PMID:Overexpression of cyclooxygenase-2 protein and its relationship to apoptosis in cervical carcinoma treated with neoadjuvant chemotherapy. 1453 98

Cyclooxygenase (COX)-2 and the prostaglandins resulting from its enzymatic activity have been shown to play a role in modulating cell growth and development of human neoplasia. Evidence includes a direct relationship between COX-2 expression and cancer incidence in humans and animal models, increased tumorigenesis after genetic manipulation of COX-2, and significant anti-tumor properties of non-steroidal anti-inflammatory drugs in animal models and in some human cancers. Recent data showed that COX-2 and the derived prostaglandins are involved in control of cellular growth, apoptosis, and signal through a group of nuclear receptors named peroxisome proliferator-activated receptors (PPARs). In this article we will review some of the findings suggesting that COX-2 is involved in multiple cellular mechanisms that lead to tumorigenesis.
J Cell Mol Med
PMID:Cyclooxygenase-2 modulates cellular growth and promotes tumorigenesis. 1459 46

Estrogens and their metabolites have been implicated in both the initiation and the prevention of breast cancer. The reduction in breast cancer incidence seen in the tamoxifen arms of the four prospective trials to date has established the proof of principle that antagonizing estrogen is a potential means of reducing breast cancer risk. However, the areas to improve on these results include: (a) enhanced efficacy, (b) reduction in the incidence of receptor-negative tumors, (c) improved overall and endocrinological side effects, and (d) improved function on end-organs other than the breast. The aromatase inhibitors offer the potential to achieve these goals in part in the following ways: (a) greater reduction in risk of disease as evidenced by superior efficacy in advanced breast cancer and by inhibition of both initiation and promotion of breast cancer, (b) reduction in receptor-negative tumors by synergy with COX-2 inhibitors resulting in growth factor inhibition, anti-angiogenesis and inhibition of tumor-associated aromatase expression, (c) fewer vasomotor and urogenital abnormalities, and (d) reduced thromboembolism and cardiovascular complications and satisfactory effects on bone metabolism. Important differences may exist between non-steroidal reversible inhibitors and steroidal irreversible inactivators in particular related to the androgenic/anabolic effects of the steroidal inactivators. Pilot studies of aromatase inhibitors described elsewhere in this session have begun in healthy women with dense mammography, or a high-risk genetic and/or histocytopathologic profile, to determine potential efficacy, as well as effects on end-organ function. A number of phase three trials with aromatase inhibitors are also underway or in planning. Among these are the BRCA 1 and 2 study of exemestane versus placebo in unaffected postmenopausal carriers, the International Breast Intervention Study 2 (IBIS 2) of anastrozole versus placebo in women with a high-risk profile, and the National Cancer Institute of Canada's Clinical Trial Group (NCIC CTG) study of exemestane with or without celecoxib versus placebo in women at risk of the disease. For premenopausal women, combination strategies of gonadotrophin agonists and aromatase inhibitors are being investigated. The potential of using low doses of aromatase inhibitors to lower "in breast" estrogen levels without unduly perturbing plasma concentrations is also being explored. The potential of the aromatase gene functioning as an oncogene within the breast may be tied to breast density which in turn may represent both a selection tool for elevated risk and an intermediate marker of prevention. The strong link between postmenopausal estrogen levels and breast cancer risk suggests the possibility that plasma estrogen levels may be a useful intermediate marker of prevention. The aromatase inhibitors offer us the first ever tool to render women virtually free of estrogen and are potentially an exciting tool for the prevention of breast cancer.
J Steroid Biochem Mol Biol 2003 Sep
PMID:Breast cancer prevention--clinical trials strategies involving aromatase inhibitors. 1462 48

Aromatase (estrogen synthase) is the cytochrome P450 enzyme complex that converts C19 androgens to C18 estrogens. Aromatase activity has been demonstrated in breast tissue in vitro, and expression of aromatase is highest in or near breast tumor sites. Thus, local regulation of aromatase by both endogenous factors as well as exogenous medicinal agents will influence the levels of estrogen available for breast cancer growth. The prostaglandin PGE2 increases intracellular cAMP levels and stimulates estrogen biosynthesis, and previous studies in our laboratories have shown a strong linear association between aromatase (CYP19) expression and expression of the cyclooxygenases (COX-1 and COX-2) in breast cancer specimens. To further investigate the pathways regulating COX and CYP19 gene expression, studies were performed in normal breast stromal cells, in breast cancer cells from patients, and in breast cancer cell lines using selective pharmacological agents. Enhanced COX enzyme levels results in increased production of prostaglandins, such as PGE2. This prostaglandin increased aromatase activity in breast stromal cells, and studies with selective agonists and antagonists showed that this regulation of signaling pathways occurs through the EP1 and EP2 receptor subtypes. COX-2 gene expression was enhanced in breast cancer cell lines by ligands for the various peroxisome proliferator-activated receptors (PPARs), and differential regulation was observed between hormone-dependent and -independent breast cancer cells. Thus, the regulation of both enzymes in breast cancer involves complex paracrine interactions, resulting in significant consequences on the pathogenesis of breast cancer.
J Steroid Biochem Mol Biol 2003 Sep
PMID:Aromatase and cyclooxygenases: enzymes in breast cancer. 1462 50

Prostaglandins modulate a wide range of biologic functions, including wound healing, temperature regulation, reproduction, and many aspects of immune function. Exaggerated production of prostaglandins contributes to a large number pathophysiologies. The critical enzyme in prostaglandin biosynthesis is prostaglandin synthase, also known as cyclooxygenase (COX). The nonsteroidal anti-inflammatory drugs (NSAIDs), one of the largest classes of pharmaceutical agents, exert most of their biologic effects by inhibiting cyclooxygenase production of prostaglandins. The discovery of a second, inducible form of cyclooxygenase, now known as COX-2, responsible for the production of prostaglandins in most pathological states, revived a relatively moribund research area in biochemistry, physiology, and pharmacology, and led to the search for and discovery of a new class of pharmacologic agents. The coxibs have greater efficacy and substantially ameliorated side effects when compared to the classic NSAIDs. Because of the pervasive role of COX-2 in a wide range of human pathologies, the coxibs have been the most successful entry into the pharmaceutical market in history, responsible for 6-10 billion dollars in sales annually. The ability to noninvasively monitor COX-2 expression with molecular imaging probes will provide a corresponding advance in diagnosing COX-2-based disease, monitoring progression of such diseases, and evaluating alternative therapies.
Mol Imaging Biol
PMID:Cyclooxygenase 2 (COX-2) as a target for therapy and noninvasive imaging. 1463 May 9

Cyclooxygenase (COX)-2 plays an important role in the development of various cancers due to its angiogenetic function. As the expression of COX-2 is up-regulated in human colorectal carcinoma and other cancers, we investigated the expression of COX-2 in human renal cell carcinoma (RCC) tissues. One hundred and eight specimens were obtained from patients with RCC, and 20 from normal kidney (NK) tissues. Immunohistochemistry, using affinity purified anti-bodies against human COX-2, and RT-PCR to study the COX-2 mRNA expression were carried out. We also examined whether or not there was a significant difference in the expression of COX-2 among grades (G1, G2, G3) and stages (pT1, pT2, pT3a, pT3b) in RCC. While no marked expression of COX-2 was observed in the NK tissues, a significantly strong expression of COX-2 was detected in RCC tissues. The extent and intensity of immunoreactive COX-2 polypeptides in cancer cells were statistically greater than those of cells from normal kidney tissues. However, no marked difference was seen among grades or between stages. These results demonstrate that the generated COX-2 in human renal cell carcinoma plays an important role in the proliferation of malignant renal cells.
Int J Mol Med 2004 Feb
PMID:Study of cyclooxygenase-2 in renal cell carcinoma. 1471 28

Acetylsalicylic acid (aspirin) is a cyclooxygenase (COX) inhibitor, yet some of its therapeutic effects are thought to derive from mechanisms unrelated to prostaglandin synthesis inhibition. In human intestinal myofibroblasts, aspirin, at therapeutic doses, had the unexpected effect of inducing prolonged COX-2 expression. This induction was especially pronounced when cells were treated with interleukin-1alpha (IL-1) plus aspirin for 24 h. Sodium salicylate, a poor COX inhibitor, likewise enhanced IL-1-mediated COX-2 gene expression whereas 5-aminosalicylic acid (5-ASA) or indomethacin had no effect. The COX-2 transcriptional rate, measured by nuclear runoff analysis and heterogeneous nuclear RNA reverse transcription-polymerase chain reaction, was only modestly elevated by aspirin treatment. In contrast, aspirin treatment dramatically stabilized the COX-2 message. The COX-2 mRNA half-life in IL-1 treated cells was 1 h and was increased in excess of 5 h in IL-1 + aspirin-treated cells. Phosphorylation of p38 MAPK was enhanced in aspirin-treated cells (but not in cells treated with 5-ASA or indomethacin) for up to 24 h after treatment. Inhibition of p38 activity negated aspirin-mediated COX-2 mRNA stabilization and the resultant increase in COX-2 mRNA and protein levels. The modest transcriptional response seen in aspirin treated cells was also abolished by p38 inhibition. We conclude that aspirin enhances COX-2 expression via sustained activation of p38, which results in prolonged stabilization of the COX-2 message and a slightly elevated transcription rate. Aspirin also enhanced steady-state mRNA levels of other IL-1 modulated genes (IL-1beta, IL-6, groalpha, and TNFalpha) that are likewise regulated at the level of message stability via p38 activation.
Mol Pharmacol 2004 Feb
PMID:Aspirin-mediated COX-2 transcript stabilization via sustained p38 activation in human intestinal myofibroblasts. 1474 90

The uterus is subject to stretch throughout pregnancy, which, in the presence of progesterone, is a potent stimulus for uterine growth. However, in the absence of progesterone or when stretch is excessive, as in multiple pregnancy, it may provoke the onset of labour. We have investigated the effect of stretch on prostaglandin synthesis in primary human uterine myocytes [non-pregnant (NP), pregnant not in labour (NL) and pregnant in labour (L)]. The cells were grown on flexible bottom culture plates and subjected to 1 or 6 h static stretch. Expression of type 2 cyclooxygenase (COX-2) mRNA was similar in samples obtained from NP and L groups and both were significantly greater than those found in the NL group. Stretch of cells from all groups resulted in increased COX-2 mRNA expression. In further studies carried out on cells taken from the NL group, 6 h of stretch resulted in increased COX-2 protein levels and, in the media, increases in prostaglandin (PG) I(2) metabolite and PGE(2) concentrations and a reduction in the concentration of PGF(2)alpha metabolites. After stretch, EMSA studies showed increased activator protein-1 (AP-1) nuclear protein DNA binding activity but not of nuclear factor kappaB. These data demonstrate that stretch of human myocytes results in increased COX-2 activity and suggest that this may occur through activation of the AP-1 system.
Mol Hum Reprod 2004 Feb
PMID:Mechanical stretch activates type 2 cyclooxygenase via activator protein-1 transcription factor in human myometrial cells. 1474 95

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of arthritis and pain. However, their long-term use is limited by gastrointestinal (GI) side effects such as gastric ulcers. NSAIDs act by inhibiting an enzyme called cyclooxygenase. Cyclooxygenase (COX) catalyses the generation of prostaglandins from arachidonic acid. Two isoforms of the enzyme exist--COX-1 and COX-2--both of which are targets for NSAIDs. Although they are associated with GI toxicity, NSAIDs have important antithrombotic and anti-inflammatory effects. The GI injury has been attributed to COX-1 inhibition and the anti-inflammatory effects to COX-2 inhibition. As COX-2 is traditionally viewed as an inducible enzyme, selective inhibition of COX-2 by 'coxibs' (selective COX-2 inhibitors) has been employed to achieve anti-inflammatory and analgesic effects without GI side effects. However, recently there have been suggestions that chronic administration of coxibs might increase the risk of cardiovascular events, such as atherosclerosis, compared with traditional NSAIDs. In vascular disease, there is increased expression of both COX-1 and COX-2, resulting in enhanced prostaglandin generation. The specific role of COX-1 and COX-2 in vascular regulation is still unknown but such knowledge is essential for the effective use of coxibs. Although more evidence is pointing to selective COX-1 inhibition as a therapeutic measure in inflammatory atherosclerosis, there are some studies that suggest that inhibition of COX-2 might have a potential benefit on atherosclerosis.
Expert Rev Mol Med 2003 Mar 07
PMID:Cyclooxygenase isoforms and atherosclerosis. 1498 12


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