Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The nicotinamide adenine dinucleotide-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH) catalyzes the oxidation of 15 (S)-hydroxyl group of prostaglandins and lipoxins and participates along with cyclooxygenases and lipoxygenases in controlling the cellular levels of prostaglandins and lipoxins. 15-PGDH could be induced by IL-6 and forskolin in addition to androgens in a time- and dose-dependent manner but not by other cytokines and growth factors in LNCaP cells. Concurrent addition of IL-6 and forskolin showed additive effect in the induction of 15-PGDH activity. However, combined addition of dihydrotestosterone (DHT) and IL-6 or DHT plus forskolin exhibited synergistic induction of 15-PGDH activity. The increase in enzyme activity was correlated with the expression of the enzyme protein as shown by Western blot analysis. The induction by DHT or IL-6 or forskolin or their combinations was inhibited by antiandrogen, casodex, in a dose-dependent manner, indicating that a functional androgen receptor was required for the action of any of these three agents. The induction by forskolin plus DHT or by either agent or by IL-6 alone was greatly inhibited by H-89, indicating the involvement of protein kinase A in the actions of forskolin, DHT, and IL-6. The induction of 15-PGDH by IL-6 was also blocked by some other protein kinase inhibitors, indicating the participation of MAPK, MAPK/ERK kinase, and STAT3 in the signaling pathway of IL-6. These results indicate that the induction of 15-PGDH by DHT, IL-6, and forskolin in LNCaP cells may involve a functional androgen receptor and phosphorylation-dependent multiple signaling pathways.
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PMID:Synergistic induction of the nicotinamide adenine dinucleotide-linked 15-hydroxyprostaglandin dehydrogenase by an androgen and interleukin-6 or forskolin in human prostate cancer cells. 1474 54

Evidence indicates that the induction of cyclooxygenase-2 (COX-2) and high prostaglandin E2 (PGE2) levels contribute to the pathogenesis of non-small-cell lung cancer (NSCLC). In addition to overproduction by COX-2, PGE2 concentrations also depend upon the levels of the PGE2 catabolic enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). We find a dramatic down-regulation of PGDH protein in NSCLC cell lines and in resected human tumors when compared with matched normal lung. Affymetrix array analysis of 10 normal lung tissue samples and 49 resected lung tumors revealed a much lower expression of PGDH transcripts in all NSCLC histologic groups. In addition, treatment with the epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) erlotinib increased the expression of 15-PGDH in a subset of NSCLC cell lines. This effect may be due in part to an inhibition of the extracellular signal-regulated kinase (ERK) pathway as treatment with mitogen-activated protein kinase kinase (MEK) inhibitor U0126 mimics the erlotinib results. We show by quantitative reverse transcription-PCR that the transcript levels of ZEB1 and Slug transcriptional repressors are dramatically reduced in a responsive cell line upon EGFR and MEK/ERK inhibition. In addition, the Slug protein, but not ZEB1, binds to the PGDH promoter and represses transcription. As these repressors function by recruiting histone deacetylases to promoters, it is likely that PGDH is repressed by an epigenetic mechanism involving histone deacetylation, resulting in increased PGE2 activity in tumors. This effect is reversible in a subset of NSCLC upon treatment with an EGFR TKI.
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PMID:Inhibition of epidermal growth factor receptor signaling elevates 15-hydroxyprostaglandin dehydrogenase in non-small-cell lung cancer. 1757 21

Prostaglandins (PGs) induce the mechanism of labor in humans. The enzymes responsible for PG synthesis and metabolism are prostaglandin-endoperoxide synthase 2 (PTGS2) and 15-hydroxyprostaglandin dehydrogenase (PGDH). In human chorion trophoblast cells, calcium ionophore A23187 upregulates PTGS2 and downregulates PGDH protein and mRNA. The authors hypothesize that this regulation requires activation of protein kinase C (PKC) and mitogen-activated protein kinases (MAPKs). Human chorion trophoblasts were incubated with A23187 or phorbol 12-myristate 13-acetate (PMA) in the absence or presence of inhibitors of PKC, c-Jun N-terminal kinase, p38, and MEK1/2. PTGS2 and PGDH mRNA were measured by real-time reverse-transcription polymerase chain reaction. PMA upregulated PTGS2 and downregulated PGDH. The PMA effect was reversed by the inhibition of PKC. The p38 inhibitor reduced the stimulatory effect of PMA and A23187 on PTGS2. MEK1/2 inhibitor reduced the effect of PMA on PTGS2. All MAPK inhibitors failed to reverse the effect of either A23187 or PMA on PGDH. The authors conclude that upon stimulation with the same upstream signals, different downstream intracellular pathways regulate PTGS2 and PGDH mRNA expression.
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PMID:Opposite effect of phorbol ester PMA on PTGS2 and PGDH mRNA expression in human chorion trophoblast cells. 1821 53

Calcitriol, the hormonally active form of vitamin D, inhibits the growth and development of several cancers. Inflammation has been implicated in the development and progression of many cancers, including prostate cancer (PCa). Recent research from our laboratory suggests that calcitriol exhibits anti-inflammatory actions that may contribute to its inhibitory effects in PCa. We found that calcitriol inhibits the synthesis and actions of pro-inflammatory prostaglandins (PGs) by three mechanisms: (1) inhibition of the expression of cyclooxygenase-2 (COX-2), the enzyme that synthesizes PGs, (2) induction of the expression of 15-prostaglandin dehydrogenase (15-PGDH), the enzyme that inactivates PGs, and (3) decreasing the expression of prostaglandin E and prostaglandin F PG receptors, which are the mediators of PG signaling. The combination of calcitriol and nonsteroidal anti-inflammatory drugs (NSAIDs) result in a synergistic inhibition of PCa cell growth and offers a potential therapeutic strategy. Acting on a separate anti-inflammatory pathway, calcitriol induces the expression of mitogen-activated protein kinase phosphatase 5 (MKP5), a member of a family of phosphatases that are negative regulators of MAP kinases, causing the selective dephosphorylation and inactivation of the stress-activated protein kinase p38. Because p38 activation may be both procarcinogenic and promote inflammation, this calcitriol action, especially coupled with the inhibition of the PG pathway, may contribute to the chemopreventive activity of calcitriol. We conclude that calcitriol exerts several anti-inflammatory actions in prostate cells, which contribute to its potential as a chemopreventive and therapeutic agent in PCa.
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PMID:Calcitriol as a chemopreventive and therapeutic agent in prostate cancer: role of anti-inflammatory activity. 1829 Jul 27

Knee osteoarthritis (OA) results, at least in part, from overloading and inflammation leading to cartilage degradation. Prostaglandin E2 (PGE2) is one of the main catabolic factors involved in OA in which metalloproteinase (MMP) is crucial for cartilage degradation. Its synthesis is the result of cyclooxygenase (COX) and prostaglandin E synthase (PGES) activities whereas NAD+-dependent 15 hydroxy-prostaglandin dehydrogenase (15-PGDH) is the key enzyme implicated in the catabolism of PGE2. Among the isoforms described, COX-1 and cytosolic PGES are constitutively expressed whereas COX-2 and microsomal PGES type 1 (mPGES-1) are inducible in an inflammatory context. We investigated the regulation of the COX, PGES and 15-PGDH and MMP-2, MMP-9 and MMP-13 genes by mechanical stress applied to cartilage explants. Mouse cartilage explants were subjected to compression (0.5 Hz, 1 MPa) from 2 to 24 h. After determination of the PGE2 release in the media, mRNA and proteins were extracted directly from the cartilage explants and analyzed by real-time RT-PCR and western blot respectively. Mechanical compression of cartilage explants significantly increased PGE2 production in a time dependent manner. This was not due to the synthesis of IL-1, since pretreatment with IL1-Ra did not alter the PGE2 synthesis. Interestingly, COX-2 and mPGES-1 mRNA expression significantly increased after 2 hours, in parallel with protein expression. Moreover, we observed a delayed overexpression of 15-PGDH just before the decline of PGE2 synthesis after 18 hours suggesting that PGE2 synthesis could be altered by the induction of 15-PGDH expression. MAPK are involved in signaling, since specific inhibitors partially inhibited COX-2 and mPGES-1 expressions. Lastly, compression induced MMP-2, -9, -13 mRNA expressions in cartilage. We conclude that dynamic compression induces pro-inflammatroy mediators release and matrix degradating enzymes synthesis. Notably, compression increases mPGES-1 mRNA and protein expression in cartilage explants. Thus, the mechanosensitive mPGES-1 enzyme represents a potential therapeutic target in osteoarthritis.
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PMID:Mechanical stress and prostaglandin E2 synthesis in cartilage. 1883 32

Multiple lines of evidence have suggested a role for both bile acids and prostaglandins (PG) in gastrointestinal carcinogenesis. Levels of PGE(2) are determined by both synthesis and catabolism. Previously, bile acid-mediated induction of cyclooxygenase-2 (COX-2) was found to stimulate PGE(2) synthesis. NAD(+)-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the key enzyme responsible for the catabolism of PGE(2), has been linked to colorectal carcinogenesis. In this study, we determined whether bile acids altered the expression of 15-PGDH in human colon cancer cell lines. Treatment with unconjugated bile acids (chenodeoxycholate and deoxycholate) suppressed the transcription of 15-PGDH, resulting in reduced amounts of 15-PGDH mRNA, protein, and enzyme activity. Conjugated bile acids were less potent suppressors of 15-PGDH expression than unconjugated bile acids. Treatment with chenodeoxycholate activated protein kinase C (PKC), leading in turn to increased extracellular signal-regulated kinase (ERK) 1/2 activity. Small molecules that inhibited bile acid-mediated activation of PKC and ERK1/2 also blocked the downregulation of 15-PGDH. Bile acids induced early growth response factor-1 (Egr-1) and Snail, a repressive transcription factor that bound to the 15-PGDH promoter. Silencing Egr-1 or Snail blocked chenodeoxycholate-mediated downregulation of 15-PGDH. Together, these data indicate that bile acids activate the signal transduction pathway PKC --> ERK1/2 --> Egr-1 --> Snail and thereby suppress 15-PGDH transcription. Bile acids appear to increase the release of PGs from cells by downregulating catabolism in addition to stimulating synthesis. These results provide new mechanistic insights into the link between bile acids and gastrointestinal carcinogenesis.
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PMID:Bile acids inhibit NAD+-dependent 15-hydroxyprostaglandin dehydrogenase transcription in colonocytes. 1960 33

Evidence points towards a pivotal role for cyclooxygenase (COX)-2 in promoting colorectal tumorigenesis through increasing prostaglandin E(2) (PGE(2)) levels. PGE(2) signalling is closely associated with the survival, proliferation and invasion of colorectal cancer cells. Recently, a reduction in PGE(2) inactivation, a process mediated by the nicotinamide adenine dinucleotide (NAD+)-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH), has also been shown to promote tumoral PGE(2) accumulation. The hepatocyte growth factor (HGF) receptor, Met, is frequently over-expressed in colorectal tumours and promotes cancer growth, metastasis and resistance to therapy, although the mechanisms for this have not been fully elucidated. Here, we report that HGF/Met signalling can promote PGE(2) biogenesis in colorectal cancer cells via COX-2 up-regulation and 15-PGDH down-regulation at the protein and messenger RNA level. Pharmacological inhibition of MEK and PI3K suggested that both extracellular signal-regulated kinase (ERK) and AKT signalling are required for COX-2 protein up-regulation and 15-PGDH down-regulation downstream of Met. Notably, inhibition of Met with the small molecule inhibitor SU11274 reduced COX-2 expression and increased 15-PGDH expression in high Met-expressing cells. We also show that hypoxia potentiated HGF-driven COX-2 expression and enhanced PGE(2) release. Furthermore, inhibition of COX-2 impeded the growth-promoting effects of HGF, suggesting that the COX-2/PGE(2) pathway is an important mediator of HGF/Met signalling. These data reveal a critical role for HGF/Met signalling in promoting PGE(2) biogenesis in colorectal cancer cells. Targeting the crosstalk between these two important pathways may be useful for therapeutic treatment of colorectal cancer.
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PMID:HGF/Met signalling promotes PGE(2) biogenesis via regulation of COX-2 and 15-PGDH expression in colorectal cancer cells. 1963 28

Calcitriol, the hormonally active form of vitamin D, exerts multiple anti-proliferative and pro-differentiating actions including cell cycle arrest and induction of apoptosis in many malignant cells, and the hormone is currently being evaluated in clinical trials as an anti-cancer agent. Recent research reveals that calcitriol also exhibits multiple anti-inflammatory effects. First, calcitriol inhibits the synthesis and biological actions of pro-inflammatory prostaglandins (PGs) by three mechanisms: i) suppression of the expression of cyclooxygenase-2, the enzyme that synthesizes PGs; ii) up-regulation of the expression of 15-hydroxyprostaglandin dehydrogenase, the enzyme that inactivates PGs; and iii) down-regulation of the expression of PG receptors that are essential for PG signaling. The combination of calcitriol and nonsteroidal anti-inflammatory drugs results in a synergistic inhibition of the growth of prostate cancer (PCa) cells and offers a potential therapeutic strategy for PCa. Second, calcitriol increases the expression of mitogen-activated protein kinase phosphatase 5 in prostate cells resulting in the subsequent inhibition of p38 stress kinase signaling and the attenuation of the production of pro-inflammatory cytokines. Third, calcitriol also exerts anti-inflammatory activity in PCa through the inhibition of nuclear factor-kappaB signaling that results in potent anti-inflammatory and anti-angiogenic effects. Other important direct effects of calcitriol as well as the consequences of its anti-inflammatory effects include the inhibition of tumor angiogenesis, invasion, and metastasis. We hypothesize that these anti-inflammatory actions, in addition to the other known anti-cancer effects of calcitriol, play an important role in its potential use as a therapeutic agent for PCa. Calcitriol or its analogs may have utility as chemopreventive agents and should be evaluated in clinical trials in PCa patients with early or precancerous disease.
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PMID:Molecular pathways mediating the anti-inflammatory effects of calcitriol: implications for prostate cancer chemoprevention and treatment. 1992 9

We investigated the tumor suppressor activity and regulatory mechanism of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) in gastric cancer; 15-PGDH expression was lost in 70.1% of malignant human gastric tissues, but was preserved in normal and metaplastic gastritis. KATO III and SNU-719 cells were transfected with pcDNA3.1-empty vector or an expression vector encoding wild-type 15-PGDH. In TUNEL assays apoptotic cell numbers were increased in KATO-PGDH-WT cells compared with control. We found that EGFR and ERK1/2 inhibitors clearly increased the expression of 15-PGDH in KATO III cells. Our findings demonstrate both downregulation and a tumor suppressor activity of 15-PGDH in gastric cancer.
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PMID:15-hydroxyprostaglandin dehydrogenase is downregulated and exhibits tumor suppressor activity in gastric cancer. 2146 75

Helicobacter pylori (H. pylori) infection induces a chronic inflammatory response, which promotes gastric carcinogenesis. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) plays a key role as a tumor suppressor in gastrointestinal cancers. The aim of this study was to elucidate the role of 15-PGDH in gastric carcinogenesis associated with H. pylori. 15-PGDH expression in gastric biopsies from H. pylori-infected (n = 25) and noninfected (n = 15) subjects was analyzed by quantitative real-time PCR, Western blot analysis, and immunohistochemistry. 15-PGDH DNA methylation was evaluated by methylation-specific PCR and pyrosequencing. The expression of 15-PGDH, Snail, extracellular signal-regulated kinase (ERK)1/2, TLR4, and MyD88 in response to H. pylori infection was assessed by immunoblot analysis. Compared with negative specimens, H. pylori-positive specimens had 2-fold lower 15-PGDH mRNA levels and significantly less 15-PGDH protein. In four H. pylori-infected subjects with longitudinal follow-up, the suppression of 15-PGDH expression was reversed by H. pylori eradication therapy. In parallel with suppressing 15-PGDH expression, H. pylori infection activated expression of TLR4 and MyD88 expression, increased levels of phospho-ERK1/2, and increased expression of EGF receptor (EGFR)-Snail. Inhibition of Snail and MyD88 reversed suppression of 15-PGDH expression, and siMyD88 reduced phosphorylated ERK1/2. Similarly, treatment with an ERK1/2 and EGFR inhibitor also restored 15-PGDH expression. H. pylori appeared to promote gastric carcinogenesis by suppressing 15-PGDH. This process is mediated by the TLR4/MyD88 pathway via ERK1/2 or EGFR-Snail transcriptional regulation. 15-PGDH may be a useful marker and a potential therapeutic target in H. pylori-induced gastric carcinogenesis.
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PMID:Inhibition of 15-hydroxyprostaglandin dehydrogenase by Helicobacter pylori in human gastric carcinogenesis. 2343 Jul 57


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