15-PGDH Activity Research Articles

Inhibition of 15-prostaglandin dehydrogenase attenuates acetaminophen-induced liver injury via suppression of apoptosis in liver endothelial cells

Hepatic microvascular disruption caused by injury to liver sinusoidal endothelial cells (LSECs) is an aggravating factor for drug-induced liver injury (DILI). It is suggested that prostaglandin E2 (PGE2) may be able to attenuate LSEC injury. However, it is also known that 15-keto PGE2, a metabolite of PGE2 produced by 15-prostaglandin dehydrogenase (15-PGDH) that is not a ligand of PGE2 receptors, suppresses inflammatory acute liver injury as a ligand of peroxisome proliferator-activated receptor γ. In this study, we aimed to understand whether 15-PGDH activity is essential for preventing DILI by suppressing hepatic microvascular disruption in a mouse model of acetaminophen (APAP)-induced liver injury. To inhibit 15-PGDH activity prior to APAP-induced LSEC injury, we administered the 15-PGDH inhibitor, SW033291, 1 h before and 3 h after APAP treatment. We observed that LSEC injury preceded hepatocellular injury in APAP administered mice. Hepatic endogenous PGE2 levels did not increase up till the initiation of LSEC injury but rather increased after hepatocellular injury. Moreover, hepatic 15-PGDH activity was downregulated in APAP-induced liver injury. The inhibition of 15-PGDH attenuated LSEC injury and subsequently hepatic injury by inhibiting apoptosis in APAP administered mice. Our in vitro studies also suggested that PGE2 inhibited APAP-induced apoptosis via the EP4/PI3K pathway in endothelial cells. Therefore, a decrease in 15-PGDH activity would be beneficial for preventing APAP-induced liver injury by attenuating LSEC injury.

15-Pgdh Inhibition Alternatively Activates Macrophages to Promote Hematopoietic Function during Aging

Aging results in the progressive decline of organ function and integrity across species. In the hematopoietic system aging is associated with diminished stem cell regenerative capacity and contributes to compromised tissue homeostasis and heightened vulnerability to age-related diseases including anemia, myelodysplastic syndromes, and hematological malignancies. Macrophages, integral components of the innate immune system, demonstrate remarkable functional plasticity and play diverse roles in tissue homeostasis, inflammation, and immunity. The balance between pro-inflammatory M1 and anti-inflammatory M2 macrophages significantly influences immune and inflammatory responses, and thus the progression of hematopoietic aging. We have previously demonstrated that the prostaglandin degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) regulates hematopoietic stem cell (HSC) activity, that 15-PGDH inhibition (PGDHi) following transplantation results in a markedly accelerated recovery of neutrophils, platelets, and HSCs, and that 15-PGDH knockout animals display enhanced HSC function with age. Here we expand on our previous work and demonstrate in aged mice that (1) 15-PGDH expression and activity remains conserved (2) that PGDHi induces a gene expression signature consistent with alternatively activated M2 macrophages, (3) that prolonged PGDHi results in a significant increase in phenotypic HSCs in both the bone marrow and spleen and induces a gene signature consistent with enhanced HSC function, and (4) that PGDHi treated bone marrow (BM) displays a advantage during primary competitive repopulation studies and prevents age-associated myeloid bias during secondary transplants. Taken together we propose PGDHi represents an in vivo switch to alternatively activate macrophages, which has significant implications to not only prevent age-associated hematopoietic decline, but also as a novel strategy to treat age-associated hematologic disease.

15-Prostaglandin Dehydrogenase Inhibition Enhances Colon Cancer Metastasis by Up-regulation of Epithelial-to-Mesenchymal Transition Genes.

Most deaths from colon cancer are due to metastasis. Recently, PGE2 was found to influence colon cancer invasion and metastasis. 15-PGDH, an enzyme that metabolizes PGE2, is known as a tumor suppressor in colonic carcinogenesis. This study investigated the effect of 15-PGDH on colon cancer metastasis. 15-PGDH expression by immunohistochemical staining, clinicopathologic features, and 5-year cancer-specific survival were investigated in colon cancer patients. Liver metastasis was examined by assaying 15-PGDH activity in an animal model. Changes in PGE2, proliferation, migration, and invasion of the colorectal cancer cell line HCT116, were examined using a 15-PGDH inhibitor (SW033291) or enhancer (CDDO-ME). The expression of genes involved in the epithelial-to-mesenchymal transition (EMT) was also studied. The absence of 15-PGDH expression significantly correlated with advanced-stage, lymph node metastasis, and decreased cancer-specific survival in colon cancer patients. Inhibition of 15-PGDH increased colon cancer liver metastasis in the animal model. The 15-PGDH inhibitor, SW033291, increased PGE2 and decreased 15-PGDH expression on HCT116. However, treatment with CDDO-ME, a substance that enhances 15-PGDH, showed the opposite results. Inhibition of 15-PGDH increased cell proliferation, migration, and invasion, but activation of 15-PGDH showed the opposite effect. Inhibition of 15-PGDH also affected the EMT markers, N-cadherin, Snail, and Twist2. 15-PGDH inhibition increased colon cancer metastasis by inducing changes in EMT-related genes via an increase in PGE2 expression and could be a promising biomarker for anticancer treatment.

Inhibition of 15-hydroxyprostaglandin dehydrogenase protects a mouse model of Alzheimer's disease without affecting amyloid pathology.

The 15-hydroxyprostaglandin dehydrogenase (15-PGDH) enzyme inactivates the lipid signaling molecule prostaglandin E2 (PGE2) by oxidizing it to 15-keto PGE2. We have previously shown that genetic elimination or pharmacologic inhibition of 15-PGDH (via the small molecule (+)-SW033291) protects peripheral organs by potentiating PGE2-mediated stem cell responses (1). Here, we investigate whether 15-PGDH expression in the brain is related to pathology in the 5xFAD mouse model of Alzheimer's disease, and if so then whether this might provide a novel route for therapy. Two month old 5xFAD mice and WT littermates received intraperitoneal injections of vehicle or (+)-SW033291 (5mg/kg twice daily) for 4 months. At 6 months of age, Morris water maze test was conducted to evaluate cognitive function, and then mice were sacrificed for immunohistochemical determination of neuronal cell survival in the hippocampus and amyloid plaque deposition. Blood-brain barrier structure was also examined by electron microscopy. Six-month-old 5xFAD mice display higher 15-PGDH activity in the brain than WT littermates. Treatment with (+)-SW033291 reduced 15-PGDH activity and protected 5xFAD mice from cognitive deficits in the Morris water maze test. This treatment also increased survival of adult-born young hippocampal neurons, as measured through bromodeoxyuridine labeling. Lastly, (+)-SW033291 treatment protected 5xFAD mice from developing blood-brain barrier disruption, as measured by the number of empty spaces around the vessel and astrocytic end-feet disruption. Notably, (+)-SW033291 treatment did not alter amyloid plaque formation in 5xFAD mice. An important element for discovering and developing disease-modifying therapies for Alzheimer's disease is diversification of targets, complementing and moving beyond the amyloid hypothesis. Pharmacologic inhibition of 15-PGDH in the brain, such as we have achieved here through treating mice with (+)-SW033291, may be an effective amyloid-independent therapeutic approach for patients.

Structural Insights into Novel 15-Prostaglandin Dehydrogenase Inhibitors.

We discovered SW033291 in a high throughput chemical screen aimed at identifying 15-prostaglandin dehydrogenase (15-PGDH) modulators. The compound exhibited inhibitory activity in in vitro biochemical and cell-based assays of 15-PGDH activity. We subsequently demonstrated that this compound, and several analogs thereof, are effective in in vivo mouse models of bone marrow transplant, colitis, and liver regeneration, where increased levels of PGE2 positively potentiate tissue regeneration. To better understand the binding of SW033291, we carried out docking studies for both the substrate, PGE2, and an inhibitor, SW033291, to 15-PGDH. Our models suggest similarities in the ways that PGE2 and SW033291 interact with key residues in the 15-PGDH-NAD+ complex. We carried out molecular dynamics simulations (MD) of SW033291 bound to this complex, in order to understand the dynamics of the binding interactions for this compound. The butyl side chain (including the sulfoxide) of SW033291 participates in crucial binding interactions that are similar to those observed for the C15-OH and the C16-C20 alkyl chain of PGE2. In addition, interactions with residues Ser138, Tyr151, and Gln148 play key roles in orienting and stabilizing SW033291 in the binding site and lead to enantioselectivity for the R-enantiomer. Finally, we compare the binding mode of (R)-S(O)-SW033291 with the binding interactions of published 15-PGDH inhibitors.

Inhibition of prostaglandin-degrading enzyme 15-PGDH rejuvenates aged muscle mass and strength.

Treatments are lacking for sarcopenia, a debilitating age-related skeletal muscle wasting syndrome. We identifed increased amounts of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the prostaglandin E2 (PGE2)-degrading enzyme, as a hallmark of aged tissues, including skeletal muscle. The consequent reduction in PGE2 signaling contributed to muscle atrophy in aged mice and results from 15-PGDH-expressing myofibers and interstitial cells, such as macrophages, within muscle. Overexpression of 15-PGDH in young muscles induced atrophy. Inhibition of 15-PGDH, by targeted genetic depletion or a small-molecule inhibitor, increased aged muscle mass, strength, and exercise performance. These benefits arise from a physiological increase in PGE2 concentrations, which augmented mitochondrial function and autophagy and decreased transforming growth factor-β signaling and activity of ubiquitin-proteasome pathways. Thus, PGE2 signaling ameliorates muscle atrophy and rejuvenates muscle function, and 15-PGDH may be a suitable therapeutic target for countering sarcopenia.

Therapeutic targeting of 15-PGDH in murine pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive disease characterized by interstitial remodeling and pulmonary dysfunction. The etiology of IPF is not completely understood but involves pathologic inflammation and subsequent failure to resolve fibrosis in response to epithelial injury. Treatments for IPF are limited to anti-inflammatory and immunomodulatory agents, which are only partially effective. Prostaglandin E2 (PGE2) disrupts TGFβ signaling and suppresses myofibroblast differentiation, however practical strategies to raise tissue PGE2 during IPF have been limited. We previously described the discovery of a small molecule, (+)SW033291, that binds with high affinity to the PGE2-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and increases PGE2 levels. Here we evaluated pulmonary 15-PGDH expression and activity and tested whether pharmacologic 15-PGDH inhibition (PGDHi) is protective in a mouse model of bleomycin-induced pulmonary fibrosis (PF). Long-term PGDHi was well-tolerated, reduced the severity of pulmonary fibrotic lesions and extracellular matrix remodeling, and improved pulmonary function in bleomycin-treated mice. Moreover, PGDHi attenuated both acute inflammation and weight loss, and decreased mortality. Endothelial cells and macrophages are likely targets as these cell types highly expressed 15-PGDH. In conclusion, PGDHi ameliorates inflammatory pathology and fibrosis in murine PF, and may have clinical utility to treat human disease.

Synthesis, Structural Analysis, and Biological Evaluation of Novel ((2,4-dioxothiazolidin-5-ylidene)methyl)phenyl Derivatives

The objective of this study was to evaluate the synthesis, structural analysis, and biological effects of novel ((2, 4-dioxothiazolidin-5-ylidene)methyl)phenyl derivatives. The efficacy of 15-PGDH inhibition increased for the substituents in the derivatives in the order: cyclohexylpropyl > cyclohexylethyl > cyclohexylmethyl > cyclohexyl. Compound 12 inhibited 15-PGDH activity by binding to the amino acids Ile 214, Ile 210, Ile 194, Gln 148, and Leu 191 of 15-PGDH. Compounds 4, 22, and 23 produced the highest increment in PGE2 concentration, which was 122.19, 100.14, and 206.80%, respectively, compared to that of the control. Also, compounds 38 and 39, in which the central phenyl ring and the 2, 4-thiazolidinedione moiety were linked by a single bond, produced a relatively high increment in PGE2 concentration, which was 106.81 and 118.66%, respectively, compared to that of the control. The wound closure rates of compounds 22 and 39 were the highest, being 247.56 and 202.42%, respectively, compared to that of the positive control. Therefore, compounds 22 and 39 could not only efficiently regulate PGE2 concentration, but also induce cellular regeneration, and are expected to effectively treat a variety of diseases resulting from PGE2 deficiency.

Inhibiting eicosanoid degradation exerts antifibrotic effects in a pulmonary fibrosis mouse model and human tissue

Idiopathic pulmonary fibrosis (IPF) is a disease with high 5-year mortality and few therapeutic options. Prostaglandin (PG) E2 exhibits antifibrotic properties and is reduced in bronchoalveolar lavage from patients with IPF. 15-Prostaglandin dehydrogenase (15-PGDH) is the key enzyme in PGE2 metabolism under the control of TGF-β and microRNA 218. We sought to investigate the expression of 15-PGDH in IPF and the therapeutic potential of a specific inhibitor of this enzyme in a mouse model and human tissue. Invitro studies, including fibrocyte differentiation, regulation of 15-PGDH, RT-PCR, and Western blot, were performed using peripheral blood from healthy donors and patients with IPF and A549 cells. Immunohistochemistry, immunofluorescence, 15-PGDH activity assays, and in situ hybridization as well as exvivo IPF tissue culture experiments were done using healthy donor and IPF lungs. Therapeutic effects of 15-PGDH inhibition were studied in the bleomycin mouse model of pulmonary fibrosis. We demonstrate that 15-PGDH shows areas of increased expression in patients with IPF. Inhibition of this enzyme increases PGE2 levels and reduces collagen production in IPF precision cut lung slices and in the bleomycin model. Inhibitor-treated mice show amelioration of lung function, decreased alveolar epithelial cell apoptosis, and fibroblast proliferation. Pulmonary fibrocyte accumulation is also decreased by inhibitor treatment in mice, similar to PGE2 that inhibits fibrocyte differentiation from blood of healthy donors and patients with IPF. Finally, microRNA 218-5p, which is downregulated in patients with IPF, suppressed 15-PGDH expression invivo and invitro. These findings highlight the role of 15-PGDH in IPF and suggest 15-PGDH inhibition as a promising therapeutic approach.

15-Deoxy-Δ12,14-prostaglandin J2 Upregulates the Expression of 15-Hydroxyprostaglandin Dehydrogenase by Inducing AP-1 Activation and Heme Oxygenase-1 Expression in Human Colon Cancer Cells.

BackgroundAbnormal upregulation of prostaglandin E2 (PGE2) is considered to be a key oncogenic event in the development and progression of inflammation-associated human colon cancer. It has been reported that 15-hydroxyprostaglandin dehydrogenase (15-PGDH), an enzyme catabolizing PGE2, is ubiquitously downregulated in human colon cancer. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), a peroxisome proliferator-activated receptor γ ligand, has been shown to have anticarcinogenic activities. In this study, we investigate the effect of 15d-PGJ2 on expression of 15-PGDH in human colon cancer HCT116 cells.MethodsHCT116 cells were treated with 15d-PGJ2 analysis. The expression of 15-PGDH in the treated cells was measured by Western blot analysis and RT-PCR. In addition, the cells were subjected to a 15-PGDH activity assay. To determine which transcription factor(s) and signaling pathway(s) are involved in 15d-PGJ2-induced 15-PGDH expression, we performed a cDNA microarray analysis of 15d-PGJ2-treated cells. The DNA binding activity of AP-1 was measured by an electrophoretic mobility shift assay. To determine whether the AP-1 plays an important role in the 15d-PGJ2-induced 15-PGDH expression, the cells were transfected with siRNA of c-Jun, a major subunit of AP-1. To elucidate the upstream signaling pathways involved in AP-1 activation by 15d-PGJ2, we examined its effect on phosphorylation of Akt by Western blot analysis in the presence or absence of kinase inhibitor.Results15d-PGJ2 (10 μM) significantly upregulated 15-PGDH expression at the mRNA and protein levels in HCT-116 cells. 15-PGDH activity was also elevated by 15d-PGJ2. We observed that genes encoding C/EBP delta, FOS-like antigen 1, c-Jun, and heme oxygenase-1 (HO-1) were most highly induced in the HCT116 cells following 15d-PGJ2 treatment. 15d-PGJ2 increased the DNA binding activity of AP-1. Moreover, transfection with specific siRNA against c-Jun significantly reduced 15-PGDH expression induced by 15d-PGJ2. 15d-PGJ2 activates Akt and a pharmacological inhibitor of Akt, LY294002, abrogated 15d-PGJ2-induced 15-PGDH expression. We also observed that an inhibitor of HO-1, zinc protoporphyrin IX, also abrogated upregulation of 15-PGDH and down-regulation of cyclooxygenase-2 expression induced by 15d-PGJ2.ConclusionsThese finding suggest that 15d-PGJ2 upregulates the expression of 15-PGDH through AP-1 activation in colon cancer HCT116 cells.

Abstract 5032: High ERbeta expression correlates with the tumor suppressor 15-PGDH and PGD2 synthase in a female cohort of colorectal cancer patients

Abstract Background: The estrogen receptor β (ERβ) is the predominant ER in the colon mucosa. We have previously reported that high expression of ERβ is independently associated with a better prognosis in female patient with colorectal cancer (CRC). β-catenin and cyclooxygenase-2 (COX-2) are well known to be involved in CRC tumorigenesis. We have shown that a high level of CysLT2R, a low level of CysLT1R and high mast cell density are correlated with good prognosis in CRC patients. β-catenin and some inflammatory mediators, such are cyclooxygenase-2 (COX-2), cysteinyl leukotriene receptor 1 and 2 (CysLT1R, CysLT2R), prostaglandin D2 (PGD2), 15-PGDH activity and mast cells have been associated with CRC. Aim: To investigate the association between ERβ and other tumor modulators in CRC patients, as well as the underlying mechanism in colon cancer cell lines. Material and methods: A tissue microarray of primary CRCs from 320 female patients was stained for the expression of ERβ, COX-2, 15-PGDH, CysLT1R, CysLT2R, ß-catenin, PGD synthase and mast cells. The Immunohistochemistry technique was used to evaluate the staining intensity, which was assigned an Immuno-Reactive Score (IRS). The zebrafish xenograft model was used to study colon cancer cells metastasis. ERβ -041 (an ERβ agonist) was injected into the zebrafish perivitelline space to allow for xamination of its effect on colon cancer cells. After 48 h, the tail, considered the distant metastatic site, was investigated for the presence of the metastasized cells. The effect of ERβ on colon cancer cells (SW-480 and HCT-116) after treatment with ERβ-041 was studied by wound healing and trans-well migration assay, as well as by survival assay. Results: Patients with high ERβ expression had significantly higher levels of membrane ß-catenin, CysLT2R, 15-PGDH and PGD synthase, which all are known to have an anti-tumor effect. These patients had significantly lower levels of CysLT1R, COX-2 and nuclear ß-catenin expression, which are known to have pro-tumorigenic effects. In addition, patients with high ERβ expression had higher numbers of mast cells, which are a major source of PGD2 synthase and PGD2. In the zebrafish xenograft model, the ERB-041 treated cells showed no distant metastasis, unlike the untreated cells. ERβ stimulation of colon cancer cells produced a significant decrease in migration and survival compared to that of the untreated control cells after 48 h post-stimulation. Conclusion: High ERβ expression was significantly correlated with anti-tumorigenic inflammatory mediators and lower nuclear ß-catenin in patients with CRC. These results strengthen our hypothesis regarding the beneficial role of ERβ in CRC patients. Our results raise the possibility of cross-talk between ERβ, CysLT1R and CysLT2R signalling. Citation Format: Geriolda Topi, Pujarini Dash, Shakti R. Satapathy, Syrina Mehrabi, Roy Ehrnström, Marie-Louise Lydrup, Anita Sjölander. High ERbeta expression correlates with the tumor suppressor 15-PGDH and PGD2 synthase in a female cohort of colorectal cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5032.

The first case of primary hypertrophic osteoarthropathy with soft tissue giant tumors caused by HPGD loss-of-function mutation.

BackgroundPrimary hypertrophic osteoarthropathy (PHO) is a rare genetic multi-organic disease characterized by digital clubbing, periostosis and pachydermia. Two genes, HPGD and SLCO2A1, which encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and prostaglandin transporter (PGT), respectively, have been reported to be related to PHO. Deficiency of aforementioned two genes leads to failure of prostaglandin E2 (PGE2) degradation and thereby elevated levels of PGE2. PGE2 plays an important role in tumorigenesis. Studies revealed a tumor suppressor activity of 15-PGDH in tumors, such as lung, bladder and breast cancers. However, to date, no HPGD-mutated PHO patients presenting concomitant tumor has been documented. In the present study, we reported the first case of HPGD-mutated PHO patient with soft tissue giant tumors at lower legs and evaluated the efficacy of selective COX-2 inhibitor (etoricoxib) treatment in the patient.MethodsIn this study, we summarized the clinical data, collected the serum and urine samples for biochemical test and analyzed the HPGD gene in our patient.ResultsA common HPGD mutation c.310_311delCT was identified in the patient. In addition to typical clinical features (digital clubbing, periostosis and pachydermia), the patient demonstrated a new clinical manifestation, a giant soft tissue tumor on the left lower leg which has not been reported in HPGD-mutated PHO patient before. After 6-month treatment with etoricoxib, the patient showed decreased PGE2 levels and improved PHO-related symptoms. Though the soft tissue tumor persisted, it seemed to be controlled under the etoricoxib treatment.ConclusionThis finding expanded the clinical spectrum of PHO and provided unique insights into the HPGD-mutated PHO.

15-Deoxy-Δ12,14-prostaglandin J2 up-regulates the expression of 15-hydroxyprostaglandin dehydrogenase through DNA methyltransferase 1 inactivation

15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is the key enzyme that catalyses the conversion of prostaglandin E2 to a keto metabolite. The expression of 15-PGDH is ubiquitously repressed in various human malignancies. However, the molecular mechanisms underlying down-regulation of 15-PGDH expression remain largely unknown. 15-Deoxy-△12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand of peroxisome proliferator-activated receptor γ, has been reported to have anti-inflammatory and anticarcinogenic activities. In the present study, we have found that 15d-PGJ2 induces expression and catalytic activity of 15-PGDH in human breast cancer (MDA-MB-231) cells. 15d-PGJ2 decreased the level of CpG methylation in the 15-PGDH promoter in MDA-MB-231 cells as determined by the bisulphite genome sequencing and methyl-specific PCR. 15d-PGJ2 inhibited the catalytic activity of methyltransferase 1 (DNMT1) but did not influence its expression. Biotinylated 15d-PGJ2 directly interacted with DNMT1 and reduced its catalytic activity. Chromatin-immunoprecipitation analysis revealed that 15d-PGJ2 significantly attenuated DNMT1 binding to the activator protein-1 transcription factor present in the 15-PGDH promoter region. A nonelectrophilic analogue 9,10-dihydro-15d-PGJ2 failed to suppress the methylation of CpG islands present in 15-PGDH promoter and did not affect both DNMT1 activity and 15-PGDH expression. These findings suggest that the α,β-unsaturated carbonyl group present in 15d-PGJ2 is essential for its inactivation on DNMT1 and expression of 15-PGDH. In conclusion, 15d-PGJ2 plays as a hypomethylating agent through direct interaction with DNMT1 and consequently suppresses DNMT1-mediated hypermethylation of 15-PGDH promoter, leading to up-regulation of 15-PGDH expression.

MicroRNA-21 induces loss of 15-hydroxyprostaglandin dehydrogenase in early gastric tubular adenocarcinoma

15-hydroxyprostaglandin dehydrogenase (15-PGDH), the rate-limiting enzyme in prostaglandin E2 degradation, is decreased in gastric cancers and microRNA (miR)-21 is one of the regulators. We investigated the expression and regulation of 15-PGDH in eary gastric carcinogenesis utilizing endoscopic submucosal dissection (ESD) and gastric cancer cell lines. Expression of 15-PGDH and cyclooxygenase-2 as well as the promoter methylation of 15-PGDH were evaluted. CRISPR, miR-21 transfection, proliferation and apoptosis assays were also done. We observed significant decreases in 15-PGDH expression but no promoter methylation was detected in any ESDs. 15-PGDH suppression by CRISPR induced enhanced growth kinetics. miR-21, which was detected in high level in gastric tumors from the TGCA data, caused increased proliferation, decreased apoptosis. miR-21 overexpression was confirmed with CISH and RT-PCR in the ESDs. Loss of 15-PGDH occurs at the very early stage of gastric adenocarcinoma by miR-21. H. pylori infection may affect miR-21 up regulation. Maintaining 15-PGDH enzyme activity could be a new strategic measure in preventing gastric cancer especially tubular adenocarcinoma.

Abstract 273: Upregulation of 15-hydroxyprostaglandin dehydrogenase expression by 15-Deoxy-Δ12,14-prostaglandin J2 through inactivation of DNA methyltransferase 1

Abstract 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) catalyzes the oxidation of prostaglandin E2 (PGE2) to a biologically inactive keto metabolite 15-keto-PGE2. However, the molecular mechanisms underlying regulation of 15-PGDH expression remain largely elusive. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand of peroxisome proliferator-activated receptor γ, has been reported to have anti-inflammatory and anti-carcinogenic activities. In the present study, we have found that 15-PGJ2 upregulates expression and catalytic activity of 15-PGDH in human breast cancer (MDA-MB-231) cells. 15d-PGJ2 treatment decreased the CpG methylation in the 15-PGDH promoter in MDA-MB-231 cells as determined by the bisulfite genome sequencing and methyl-specific PCR. 15d-PGJ2 inhibited catalytic activity of methyltransferase 1 (DNMT1) but did not influence DNMT expression. 15d-PGJ2 increased the expression of c-Fos which is a functional subunit of AP-1. Chromatin-immunoprecipitation analysis revealed that 15d-PGJ2 significantly attenuated DNMT1 binding to the site for AP-1 transcription factor present in the 15-PGDH promoter regions, while increasing c-Fos binding. Biotin-tagged 15d-PGJ2 directly bound to DNMT1, and reduced its catalytic activity. A non-electrophilic analogue 9,10-dihydro-15d-PGJ2 failed to suppress the methylation of CpG islands present in 15-PGDH promoter and did not affect both DNMT1 activity and 15-PGDH expression. This findings suggests that the α,β-unsaturated carbonyl group of 15d-PGJ2 is essential for its inactivation of DNMT1 and expression of 15-PGDH. In conclusion, 15d-PGJ2 directly interacts with DNMT1 and consequently suppresses DNMT1-mediated hypermethylation of 15-PGDH promoter, leading to upregulation of 15-PGDH expression. Citation Format: Hye-Ok Jang, Hye-Rim Kim Kim, Ha-Na Lee, Do-Hee Kim, Young-Joon Surh, Hye-Kyung Na. Upregulation of 15-hydroxyprostaglandin dehydrogenase expression by 15-Deoxy-Δ12,14-prostaglandin J2 through inactivation of DNA methyltransferase 1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 273.

Increased 15-PGDH expression leads to dysregulated resolution responses in stromal cells from patients with chronic tendinopathy

The mechanisms underpinning the failure of inflammation to resolve in diseased musculoskeletal soft tissues are unknown. Herein, we studied bioactive lipid mediator (LM) profiles of tendon-derived stromal cells isolated from healthy donors and patients with chronic tendinopathy. Interleukin(IL)-1β treatment markedly induced prostaglandin biosynthesis in diseased compared to healthy tendon cells, and up regulated the formation of several pro-resolving mediators including 15-epi-LXA4 and MaR1. Incubation of IL-1β stimulated healthy tendon cells with 15-epi-LXA4 or MaR1 down-regulated PGE2 and PGD2 production. When these mediators were incubated with diseased cells, we only found a modest down regulation in prostanoid concentrations, whereas it led to significant decreases in IL-6 and Podoplanin expression. In diseased tendon cells, we also found increased 15-Prostaglandin Dehydrogenase (15-PGDH) expression as well as increased concentrations of both 15-epi-LXA4 and MaR1 further metabolites, 15-oxo-LXA4 and 14-oxo-MaR1. Inhibition of 15-PGDH using either indomethacin or SW033291 significantly reduced the further conversion of 15-epi-LXA4 and MaR1 and regulated expression of IL-6, PDPN and STAT-1. Taken together these results suggest that chronic inflammation in musculoskeletal soft tissues may result from dysregulated LM-SPM production, and that inhibition of 15-PGDH activity together with promoting resolution using SPM represents a novel therapeutic strategy to resolve chronic tendon inflammation.

Activation of PPARγ by endogenous prostaglandin J2 mediates the antileukemic effect of selenium in murine leukemia

AbstractSupplementation with nontoxic doses of micronutrient selenium has been shown to alleviate chronic myelogenous leukemia (CML) via the elimination of leukemia stem cells (LSCs) in mice. This treatment provides a new and novel method for eliminating the LSCs that are otherwise not targeted by existing therapies. The antileukemic effect of selenium was dependent on the production of endogenous cyclopentenone prostaglandins (CyPGs), Δ-12 prostaglandin J2 (Δ12-PGJ2), and 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2). Here, we show that these endogenous CyPGs, produced by mice maintained on selenium-supplemented diets, alleviate the symptoms of CML through their ability to activate the nuclear hormone receptor, peroxisome proliferator activated receptor γ (PPARγ). GW9662, a potent PPARγ antagonist, blocked the antileukemic effect of selenium supplementation by significantly reducing CyPGs. This effect was mediated by an increase in 15-prostaglandin dehydrogenase (15-Pgdh) activity, which oxidizes and inactivates Δ12-PGJ2 and 15d-PGJ2. In contrast, treatment with the PPARγ agonist pioglitazone mimicked selenium supplementation. This treatment led to decreased 15-Pgdh activity and increased CyPG levels, which inhibited CML progression. Selenium-dependent activation of PPARγ mediated by endogenous CyPGs decreased Stat5 expression leading to the downregulation of Cited2, a master regulator of LSC quiescence. These studies suggest a potential role for selenium supplementation as an adjuvant therapy in CML.

Chronic unpredictable mild stress induces parallel reductions of 15-PGDH in the hypothalamus and lungs in rats

Prostaglandin E2 (PGE2) is an important inflammatory mediator and considered to be involved in the pathophysiology of depression. Previous studies that investigated the role of PGE2 in depression solely concentrated on the cyclooxygenase-dependent synthesis of this bioactive lipid. However, enzymes that degrade PGE2, such as NAD+-dependent 15-hydroxyprostaglandin dehydrogenase (15-PGDH), have not yet been explored. The present study examined the expression of 15-PGDH in an animal model of depression. Depressive-like behaviors were measured after rats were exposed to chronic unpredictable mild stress (CUMS). 15 PGDH mRNA and protein expression and activity and PGE2 levels were detected in the brain and lungs in stressed animals. The stressed animals exhibited decreases in body weight gain, locomotor activity in the open field, and sucrose preference. The hypothalamus and lungs had high baseline 15-PGDH mRNA and protein expression, whereas the frontal cortex and hippocampus showed no detectable 15-PGDH mRNA or protein expression. 15 PGDH mRNA and protein expression was significantly downregulated in the hypothalamus and lungs in stressed rats compared with control rats, and the enzymatic activity of 15-PGDH was correlated with protein expression levels. PGE2 concentrations in the brain and serum increased in stressed rats. These results suggest the loss of 15-PGDH expression in depression, and 15-PGDH may be a novel potential pharmacological target for the treatment of depression.

Abstract 2297: 15-Deoxy-Δ12,14-prostaglandin J2 upregulates the expression of 15-hydroxyprostaglandin dehydrogenase through DNA methyltrasferase 1 inactivation

Abstract 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is the key enzyme that catalyzes the conversion of prostaglandin E2 to a biologically inactive keto metabolite. The down regulation of 15-PGDH is ubiquitously observed in various human malignancies including breast cancer. Hypermethylation of CpG islands present in the gene promoter region is considered to silence the expression of 15-PGDH. However, the molecular mechanisms underlying regulation of 15-PGDH remain largely unknown. 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), an endogenous ligand of peroxisome proliferator-activated receptor γ, has been reported to have anti-inflammatory and anti-carcinogenic activities. In the present study, we have found that 15-PGJ2 upregulates expression and catalytic activity of 15-PGDH in human breast cancer (MDA-MB-231) cells. 15d-PGJ2 decreased the level of CpG methylation in the 15-PGDH promoter in MDA-MB-231 cells as determined by the bisulfite genome sequencing and methyl specific PCR. 15d-PGJ2 inhibited catalytic activity of methyltransferase 1 (DNMT1) but did not influence expression of either mRNA or protein of DNMT1. siRNA knockdown of DNMT1 induced expression of 15-PGDH. Biotinylated 15d-PGJ2 directly interacted with DNMT1 and reduced its catalytic activity. Chromatin-immunoprecipitation analysis revealed that 15d-PGJ2 significantly attenuated DNMT1 binding to the site for AP-1 transcription factor present in the 15-PGDH promoter regions. We also observed that 15-PGJ2 induced expression of c-Fos, but not c-Jun in the nuclear extract of MDA-MD-231 cells. Moreover, 15d-PGJ2 increased the c-Fos binding to the 15-PGDH promoter regions. A non-electrophilic analogue 9,10-dihydro-15d-PGJ2 failed to suppress the methylation of CpG islands present in 15-PGDH promoter and did not affect DNMT1 activity and 15-PGDH expression. This finding suggests that the α,β-unsaturated carbonyl group is essential for 15d-PGJ2-mediated inactivation of DNMT1 and expression of 15-PGDH. In conclusion, 15d-PGJ2 plays as a hypomethylating agent through direct interaction with DNMT1 and thereby suppresses DNMT1-mediated hypermethylation of 15-PGDH promoter, leading to upregulation of 15-PGDH expression. Citation Format: Hye-Ok Jang, Ha-Na Lee, Areumnuri Kim, Do-Hee Kim, Young-Joon Surh, Hye-Kyung Na. 15-Deoxy-Δ12,14-prostaglandin J2 upregulates the expression of 15-hydroxyprostaglandin dehydrogenase through DNA methyltrasferase 1 inactivation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2297. doi:10.1158/1538-7445.AM2014-2297

15-Deoxy-Δ12,14-prostaglandin J2 induces expression of 15-hydroxyprostaglandin dehydrogenase through Elk-1 activation in human breast cancer MDA-MB-231 cells

Overproduction of prostaglandin E2 (PGE2) has been reported to be implicated in carcinogenesis. The intracellular level of PGE2 is maintained not only by its biosynthesis, but also by inactivation/degradation. 15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is the key enzyme that catalyzes the conversion of oncogenic PGE2 to a biologically inactive keto metabolite. In the present study, we demonstrate that 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), one of the terminal products of cyclooxygenase-2, updregulates the expression and the activity of 15-PGDH in human breast cancer MDA-MB-231 cells. By using deletion constructs of the 15-PGDH promoter, we have found that E-twenty six (Ets) is the most essential determinant for 15-PGDH induction. 15d-PGJ2 induced phosphorylation of Elk-1, one of Ets transcription factor family members, in the nucleus. Knockdown of Elk-1 abolished the ability of 15d-PGJ2 to upregulate 15-PGDH expression. Furthermore, 15d-PGJ2-mediated activation of Elk-1 was found to be dependent on activation of extracellular-signal related kinase (ERK) 1/2. Treatment of U0126, a pharmacological inhibitor of MEK1/2-ERK, abolished phosphorylation and DNA binding of Elk-1 as well as 15-PGDH induction in 15d-PGJ2-treated MDA-MB-231 cells. Moreover, 15d-PGJ2 generated reactive oxygen species (ROS), which contribute to the expression of 15-PGDH as well as phosphorylation of ERK1/2 and Elk-1. 15d-PGJ2 inhibited the migration of MDA-MB-231 cells, which was attenuated by transient transfection with 15-PGDH siRNA. Taken together, these findings suggest that 15d-PGJ2 induces the expression of 15-PGDH through ROS-mediated activation of ERK1/2 and subsequently Elk-1 in the MDA-MB-231 cells, which may contribute to tumor suppressive activity of this cyclopentenone prostaglandin.