Structure-guided optimization of 3-hydroxybenzoisoxazole derivatives as inhibitors of Aldo-keto reductase 1C3 (AKR1C3) to target prostate cancer.

AKR1C3 is an enzyme that is overexpressed in several types of radiotherapy- and chemotherapy-resistant cancers. Despite AKR1C3 is a validated target for drug development, no inhibitor has been approved for clinical use. In this manuscript, we describe our study of a new series of potent AKR1C3-targeting 3-hydroxybenzoisoxazole based inhibitors that display high selectivity over the AKR1C2 isoform and low micromolar activity in inhibiting 22Rv1 prostate cancer cell proliferation. In silico studies suggested proper substituents to increase compound potency and provided with a mechanistic explanation that could clarify their different activity, later confirmed by X-ray crystallography. Both the in-silico studies and the crystallographic data highlight the importance of 90° rotation around the single bond of the biphenyl group, in ensuring that the inhibitor can adopt the optimal binding mode within the active pocket. The p-biphenyls that bear the meta-methoxy, and the ortho- and meta-trifluoromethyl substituents (in compounds 6a, 6e and 6f respectively) proved to be the best contributors to cellular potency as they provided the best IC50 values in series (2.3, 2.0 and 2.4 µM respectively) and showed no toxicity towards human MRC-5 cells. Co-treatment with scalar dilutions of either compound 6 or 6e and the clinically used drug abiraterone led to a significant reduction in cell proliferation, and thus confirmed that treatment with both CYP171A1-and AKR1C3-targeting compounds possess the potential to intervene in key steps in the steroidogenic pathway. Taken together, the novel compounds display desirable biochemical potency and cellular target inhibition as well as good in-vitro ADME properties, which highlight their potential for further preclinical studies.

Inhibition of aldo-keto reductase 1C3 overcomes gemcitabine/cisplatin resistance in bladder cancer.

Systemic chemotherapy with gemcitabine and cisplatin (GC) has been used for the treatment of bladder cancer in which androgen receptor (AR) signaling is suggested to play a critical role. However, its efficacy is often limited, and the prognosis of patients who develop resistance is extremely poor. Aldo-keto reductase 1C3 (AKR1C3), which is responsible for the production of a potent androgen, 5α-dihydrotestosterone (DHT), by the reduction of 5α-androstane-3α,17ß-dione (5α-Adione), has been attracting attention as a therapeutic target for prostate cancer that shows androgen-dependent growth. By contrast, the role of AKR1C3 in bladder cancer remains unclear. In this study, we examined the effect of an AKR1C3 inhibitor on androgen-dependent proliferation and GC sensitivity in bladder cancer cells. 5α-Adione treatment induced the expression of AR and its downstream factor ETS-domain transcription factor (ELK1) in both T24 cells and newly established GC-resistant T24GC cells, while it did not alter AKR1C3 expression. AKR1C3 inhibitor 2j significantly suppressed 5α-Adione-induced AR and ELK1 upregulation, as did an AR antagonist apalutamide. Moreover, the combination of GC and 2j in T24GC significantly induced apoptotic cell death, suggesting that 2j could enhance GC sensitivity. Immunohistochemical staining in surgical specimens further revealed that strong expression of AKR1C3 was associated with significantly higher risks of tumor progression and cancer-specific mortality in patients with muscle-invasive bladder cancer. These results suggest that AKR1C3 inhibitors as adjunctive agents enhance the efficacy of GC therapy for bladder cancer.

Crystal structure determination, molecular docking, and molecular dynamics of arylal dimedones as potential inhibitors for castrate-resistant prostate cancer.

Increased androgen receptor (AR) signaling brought on by higher intratumoral androgen production and AR amplification is associated with castrate-resistant prostate cancer (CRPC). Cell proliferation in this case continues even during low expression of testosterone in the body. Aldo-keto reductase family 1 member C3 (AKR1C3) is one of the most elevated genes in CRPC and catalyzes the formation of powerful AR ligands from inactive forms. The current work aimed to use the x-ray method to investigate the ligand's crystal structure while also conducting molecular docking and molecular dynamics tests on the synthesized molecules against AKR1C3. As per the results obtained, the MM-PBSA binding energies of inhibitors 2,2'-((4-methoxyphenyl)methylene)bis(3,4-hydroxy-5,5-dimethylcyclohex-2-en-1-one is -132.456 kJ mol-1 and 2,2'-(phenylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-one is -81.017 kJ mol-1 . These results create a promising approach to drug design based on its fit to the structures of the receptor site rather than basing it on analogies to other active structures.

Novel aldo-keto reductase 1C3 inhibitor affects androgen metabolism but not ovarian function in healthy women: a phase 1 study.

OBJECTIVE: Aldo-keto reductase 1C3 (AKR1C3) has been postulated to be involved in androgen, progesterone, and estrogen metabolism. Aldo-keto reductase 1C3 inhibition has been proposed for treatment of endometriosis and polycystic ovary syndrome. Clinical biomarkers of target engagement, which can greatly facilitate drug development, have not yet been described for AKR1C3 inhibitors. Here, we analyzed pharmacodynamic data from a phase 1 study with a new selective AKR1C3 inhibitor, BAY1128688, to identify response biomarkers and assess effects on ovarian function. DESIGN: In a multiple-ascending-dose placebo-controlled study, 33 postmenopausal women received BAY1128688 (3, 30, or 90 mg once daily or 60 mg twice daily) or placebo for 14 days. Eighteen premenopausal women received 60 mg BAY1128688 once or twice daily for 28 days. METHODS: We measured 17 serum steroids by liquid chromatography-tandem mass spectrometry, alongside analysis of pharmacokinetics, menstrual cyclicity, and safety parameters. RESULTS: In both study populations, we observed substantial, dose-dependent increases in circulating concentrations of the inactive androgen metabolite androsterone and minor increases in circulating etiocholanolone and dihydrotestosterone concentrations. In premenopausal women, androsterone concentrations increased 2.95-fold on average (95% confidence interval: 0.35-3.55) during once- or twice-daily treatment. Note, no concomitant changes in serum 17ß-estradiol and progesterone were observed, and menstrual cyclicity and ovarian function were not altered by the treatment. CONCLUSIONS: Serum androsterone was identified as a robust response biomarker for AKR1C3 inhibitor treatment in women. Aldo-keto reductase 1C3 inhibitor administration for 4 weeks did not affect ovarian function.ClinicalTrials.gov Identifier: NCT02434640; EudraCT Number: 2014-005298-36.

Development of highly potent and specific AKR1C3 inhibitors to restore the chemosensitivity of drug-resistant breast cancer.

Aldo-keto reductase 1C3 (AKR1C3) is overexpressed in multiple hormone related cancers, such as breast and prostate cancer, and is correlated with tumor development and aggressiveness. As a phase I biotransformation enzyme, AKR1C3 catalyzes the metabolic processes that lead to resistance to anthracyclines, the "gold standard" for breast cancer treatment. Novel approaches to restore the chemotherapy sensitivity of breast cancer are urgently required. Herein, we developed a new class of AKR1C3 inhibitors that demonstrated potent inhibitory activity and exquisite selectivity for closely related isoforms. The best derivative 27 (S19-1035) exhibits an IC50 value of 3.04 nM for AKR1C3 and >3289-fold selectivity over other isoforms. We determined the co-crystal structures of AKR1C3 with three of the inhibitors, providing a solid foundation for further structure-based drug optimization. Co-administration of these AKR1C3 inhibitors significantly reversed the doxorubicin (DOX) resistance in a resistant breast cancer cell line. Therefore, the novel AKR1C3 specific inhibitors developed in this work may serve as effective adjuvants to overcome DOX resistance in breast cancer treatment.

Computational modeling studies reveal the origin of the binding preference of 3-(3,4-di hydroisoquinolin-2(1H)-ylsulfonyl)benzoic acids for AKR1C3 over its isoforms.

As a key regulator for hormone activity, human aldo-keto reductase family 1 member C3 (AKR1C3) plays crucial roles in the occurrence of various hormone-dependent or independent malignancies. It is a promising target for treating castration-resistant prostate cancer (CRPC). However, the development of AKR1C3 specific inhibitors remains challenging due to the high sequence similarity to its isoform AKR1C2. Here, we performed a combined in silico study to illuminate the inhibitory preference of 3-(3,4-dihydroisoquinolin-2(1H)-ylsulfonyl)benzoic acids for AKR1C3 over AKR1C2, of which compound 38 can achieve up to 5000-fold anti-AKR1C3 selectivity. Our umbrella sampling (US) simulations together with end-point binding free energy calculation MM/GBSA uncover that the high inhibition selectivity originates from the different binding modes, namely "Inward" and "Outward," of this compound series in AKR1C3 and AKR1C2, respectively. In AKR1C3/38, the tetrahydroquinoline moiety of 38 is accommodated inside the SP1 pocket and interacts favorably with surrounding residues, while, in AKR1C2/38, the SP1 pocket is too small to hold the bulky tetrahydroquinoline group that instead moves out of the pocket with 38 transitioning from an "Inward" to an "Outward" state. Further 3D-QSAR and energy decomposition analyses suggest that SP1 in AKR1C3 prefers to bind with a rigid bicyclic moiety and the modification of the R3 group has important implication for the compound's activity. This work is the first attempt to elucidate the selectivity mechanism of inhibitors toward AKR1C3 at the atomic level, which is anticipated to propel the development of next-generation AKR1C3 inhibitors with enhanced efficacy and reduced "off-target" effect for CRPC therapy.

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

BACKGROUND/AIM: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Smad4-deficient T cells promote colitis-associated colon cancer via an IFN-γ-dependent suppression of 15-hydroxyprostaglandin dehydrogenase.

Immune cells and the cytokines they produce are important mediators of the transition from colitis to colon cancer, but the mechanisms mediating this disease progression are poorly understood. Interferon gamma (IFN-γ) is known to contribute to the pathogenesis of colitis through immune modulatory mechanisms, and through direct effects on endothelial and epithelial homeostasis. Here we explore whether IFN-γ influences tumor progression by expanding the effector memory T cells (TEM) population and restricting the expression of tumor suppressors in a preclinical model of spontaneous colitis-associated colorectal cancer (CAC). We show that IFN-γ expression is significantly increased both in the T cells and the colonic mucosal epithelia of mice with a T cell-restricted deletion of the TGF-ß intermediate, SMAD4 (Smad4TKO). The increase of IFN-γ expression correlates with the onset of spontaneous CAC in Smad4TKO mice by 6 months of age. This phenotype is greatly ameliorated by the introduction of a germline deletion of IFN-γ in Smad4TKO mice (Smad4TKO/IFN-γKO, DKO). DKO mice had a significantly reduced incidence and progression of CAC, and a decrease in the number of mucosal CD4+ TEM cells, when compared to those of Smad4TKO mice. Similarly, the colon epithelia of DKO mice exhibited a non-oncogenic signature with a decrease in the expression of iNOS and p-STAT1, and a restoration of the tumor suppressor gene, 15-hydroxyprostaglandin dehydrogenase (15-PGDH). In vitro, treatment of human colon cancer cells with IFN-γ decreased the expression of 15-PGDH. Our data suggest that Smad4-deficient T cells promote CAC through mechanisms that include an IFN-γ-dependent suppression of the tumor suppressor 15-PGDH.

Tumor microenvironmental 15-PGDH depletion promotes fibrotic tumor formation and angiogenesis in pancreatic cancer.

The arachidonic acid cascade is a major inflammatory pathway that produces prostaglandin E2 (PGE2). Although inhibition of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is reported to lead to PGE2 accumulation, the role of 15-PGDH expression in the tumor microenvironment remains unclear. We utilized Panc02 murine pancreatic cancer cells for orthotopic transplantation into wild-type and 15-pgdh+/- mice and found that 15-pgdh depletion in the tumor microenvironment leads to enhanced tumorigenesis accompanied by an increase in cancer-associated fibroblasts (CAFs) and the promotion of fibrosis. The fibrotic tumor microenvironment is widely considered to be hypovascular; however, we found that the angiogenesis level is maintained in 15-pgdh+/- mice, and these changes were also observed in a genetically engineered PDAC mouse model. Further confirmation revealed that fibroblast growth factor 1 (FGF1) is secreted by pancreatic cancer cells after PGE2 stimulation, consequently promoting CAF proliferation and vascular endothelial growth factor A (VEGFA) expression in the tumor microenvironment. Finally, in 15-pgdh+/- Acta2-TK mice, depletion of fibroblasts inhibited angiogenesis and cancer cell viability in orthotopically transplanted tumors. These findings highlighted the role of 15-pgdh downregulation in enhancing PGE2 accumulation in the pancreatic tumor microenvironment and in subsequently maintaining the angiogenesis level in fibrotic tumors along with CAF expansion.

MiR-106b-5p regulates esophageal squamous cell carcinoma progression by binding to HPGD.

BACKGROUND: Several studies have documented the key role of microRNAs (miRNAs) in esophageal squamous cell carcinoma (ESCC). Although the expression of the 15-hydroxyprostaglandin dehydrogenase (HPGD) gene and miR-106b-5p are reportedly linked to cancer progression, their underlying mechanisms in ESCC remain unclear. METHODS: mRNA and miRNA expression in ESCC tissues and cells were analyzed using RT-qPCR. Luciferase and RNA pull-down assays were used to identify the interaction between miR-106b-5p and HPGD. Xenograft and pulmonary metastasis models were used to assess tumor growth and metastasis. CCK-8, BrdU, colony formation, adhesion, cell wound healing, Transwell, and caspase-3/7 activity assays, and flow cytometry and western blot analyses were used to examine the function of miR-106-5p and HPGD in ESCC cell lines. RESULTS: The findings revealed that miR-106b-5p expression was upregulated in ESCC tissues and cell lines. miR-106b-5p augmented cellular proliferation, colony formation, adhesion, migration, invasion, and proportion of cells in the S-phase, but reduced apoptosis and the proportion of cells in G1-phase. Silencing of miR-106-5p inhibited tumor growth in vivo and pulmonary metastasis. Although HPGD overexpression suppressed proliferation, colony formation, adhesion, migration, and invasion of ESCC cells, it promoted apoptosis and caused cell cycle arrest of the ESCC cells. The results also indicated a direct interaction of HPGD with miR-106b-5p in ESCC cells. Furthermore, miR-106b-5p inhibited HPGD expression, thereby suppressing ESCC tumorigenesis. CONCLUSION: Our data suggest that miR-106b-5p enhances proliferation, colony formation, adhesion, migration, and invasion, and induces the cycle progression, but represses apoptosis of ESCC cells by targeting HPGD. This suggests that the miR-106b-5p/HPGD axis may serve as a promising target for the diagnosis and treatment of ESCC.

Recent advances in studies of 15-PGDH as a key enzyme for the degradation of prostaglandins.

15-hydroxyprostaglandin dehydrogenase (15-PGDH; encoded by HPGD) is ubiquitously expressed in mammalian tissues and catalyzes the degradation of prostaglandins (PGs; mainly PGE2, PGD2, and PGF2α) in a process mediated by solute carrier organic anion transport protein family member 2A1 (SLCO2A1; also known as PGT, OATP2A1, PHOAR2, or SLC21A2). As a key enzyme, 15-PGDH catalyzes the rapid oxidation of 15-hydroxy-PGs into 15-keto-PGs with lower biological activity. Increasing evidence suggests that 15-PGDH plays a key role in many physiological and pathological processes in mammals and is considered a potential pharmacological target for preventing organ damage, promoting bone marrow graft recovery, and enhancing tissue regeneration. Additionally, results of whole-exome analyses suggest that recessive inheritance of an HPGD mutation is associated with idiopathic hypertrophic osteoarthropathy. Interestingly, as a tumor suppressor, 15-PGDH inhibits proliferation and induces the differentiation of cancer cells (including those associated with colorectal, lung, and breast cancers). Furthermore, a recent study identified 15-PGDH as a marker of aging tissue and a potential novel therapeutic target for resisting the complex pathology of aging-associated diseases. Here, we review and summarise recent information on the molecular functions of 15-PGDH and discuss its pathophysiological implications.

Solidagenone from Solidago chilensis Meyen inhibits skin inflammation in experimental models.

Solidagenone (SOL) is a labdane-type diterpenoid found in Solidago chilensis, a plant traditionally used to treat skin diseases, kidney pain and ovarian inflammation. In this study, the topical anti-inflammatory activity of SOL was evaluated using in vivo and in silico assays. Croton oil-, arachidonic acid (AA)- and phenol-induced ear oedema mouse models were applied in the in vivo studies. Myeloperoxidase (MPO) and N-acetyl-ß-D-glucosaminidase (NAG) activities and tumour necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and nitric oxide (NO) levels were determined, as well as histopathological analyses were conducted. Interaction profiles between SOL and cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), glucocorticoid receptor, estradiol-17-ß-dehydrogenase and prostaglandin-E(2)-9-reductase were established using molecular docking. SOL significantly inhibited croton oil-, AA- and phenol-induced ear oedema (P < .001) at doses of 0.1, 0.5 and 1.0 mg/ear. The MPO and NAG activities and TNF-α, IL-6 and NO levels were decreased (P < .001). The histopathological data revealed that inflammatory parameters (oedema thickness, leucocyte infiltration and vasodilatation) were reduced by treatment with SOL at doses of 0.1, 0.5 and 1.0 mg/ear. The docking study showed that SOL interacts with COX-1 and prostaglandin-E(2)-9-reductase through hydrogen bonding, inhibiting these enzymes. These results indicate that SOL may be a promising compound for the treatment of cutaneous inflammatory disorders and has potential as a topical anti-inflammatory agent.

Inflammation Modulation by Vitamin D and Calcium in the Morphologically Normal Colorectal Mucosa of Patients with Colorectal Adenoma in a Clinical Trial.

Increased COX-2 and decreased 15-hydroxyprostaglandin dehydrogenase (15-HPGD) expression promote prostaglandin-mediated inflammation and colorectal carcinogenesis. Experimental studies suggest that vitamin D and calcium may inhibit these pathways, but their effects on colorectal tissue COX-2 and 15-HPGD expression in humans are unknown. We tested the effects of supplemental vitamin D (1,000 IU/day) and/or calcium (1,200 mg/day) on COX-2 and 15-HPGD expression in the morphologically normal rectal mucosa from 62 paients with colorectal adenoma in a placebo-controlled chemoprevention trial. We measured biomarker expression using automated IHC and quantitative image analysis at baseline and 1-year follow-up, and assessed treatment effects using mixed linear models. The primary outcome was the COX-2/15-HPGD expression ratio, because these enzymes function as physiologic antagonists. After 1 year of treatment, the mean COX-2/15-HPGD expression ratio in full-length crypts proportionately decreased 47% in the vitamin D group (P = 0.001), 46% in the calcium group (P = 0.002), and 34% in the calcium + vitamin D group (P = 0.03), relative to the placebo group. Among individuals with the functional vitamin D-binding protein isoform DBP2 (GC rs4588*A), the COX-2/15-HPDG ratio decreased 70% (P = 0.0006), 75% (P = 0.0002), and 60% (P = 0.006) in the vitamin D, calcium, and combined supplementation groups, respectively, relative to placebo. These results show that vitamin D and calcium favorably modulate the balance of expression of COX-2 and 15-HPGD-biomarkers of inflammation that are strongly linked to colorectal carcinogenesis-in the normal-appearing colorectal mucosa of patients with colorectal adenoma (perhaps especially those with the DBP2 isoform). PREVENTION RELEVANCE: Supplemental calcium and vitamin D reduce indicators of cancer-promoting inflammation in normal colorectal tissue in humans, thus furthering our understanding of how they may help prevent colorectal cancer.

Inhibition of 15-PGDH prevents ischemic renal injury by the PGE2/EP4 signaling pathway mediating vasodilation, increased renal blood flow, and increased adenosine/A2A receptors.

In the present study, we demonstrated the marked activity of SW033291, an inhibitor of 15-hydoxyprostaglandin dehydrogenase (15-PGDH), in preventing acute kidney injury (AKI) in a murine model of ischemia-reperfusion injury. AKI due to ischemic injury represents a significant clinical problem. PGE2 is vasodilatory in the kidney, but it is rapidly degraded in vivo due to catabolism by 15-PGDH. We investigated the potential of SW033291, a potent and specific 15-PGDH inhibitor, as prophylactic treatment for ischemic AKI. Prophylactic administration of SW033291 significantly increased renal tissue PGE2 levels and increased post-AKI renal blood flow and renal arteriole area. In parallel, prophylactic SW033291 decreased post-AKI renal morphology injury scores and tubular apoptosis and markedly reduced biomarkers of renal injury that included blood urea nitrogen, creatinine, neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1. Prophylactic SW033291 also reduced post-AKI induction of proinflammatory cytokines, high-mobility group box 1, and malondialdehyde. Protective effects of SW033291 were mediated by PGE2 signaling, as they could be blocked by pharmacological inhibition of PGE2 synthesis. Consistent with activation of PGE2 signaling, SW033291 induced renal levels of both EP4 receptors and cAMP, along with other vasodilatory effectors, including AMP, adenosine, and the adenosine A2A receptor. The protective effects of SW0333291 could largely be achieved with a single prophylactic dose of the drug. Inhibition of 15-PGDH may thus represent a novel strategy for prophylaxis of ischemic AKI in multiple clinical settings, including renal transplantation and cardiovascular surgery.

Prostaglandin E2 Pathway Is Dysregulated in Gastric Adenocarcinoma in a Caucasian Population.

Gastric cancer (GC) represents the third leading cause of cancer-related deaths worldwide. The levels of prostaglandin E2, a key player in the hallmarks of cancer, are mainly regulated by prostaglandin-endoperoxide synthase 2 (PTGS2) and ATP-binding cassette subfamily C member 4 (ABCC4), involved in its synthesis and exportation, respectively, and 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and solute carrier organic anion transporter family member 2A1 (SLCO2A1), responsible for its inactivation. Even though there are distinct molecular signatures across ethnic populations, most published studies focus on Asian populations. Our main aim was to explore the genetic expression of the aforementioned molecules in a Caucasian population. 94 "Normal" and 89 tumoral formalin-fixed paraffin-embedded (FFPE) samples from GC patients were used to assess the mRNA expression of PTGS2, ABCC4, hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD), SLCO2A1 by Real-Time PCR. We found an upregulation for the PTGS2 gene mean factor of 2.51 and a downregulation for the HPGD and SLCO2A1 genes (mean factor of 0.10 and 0.37, respectively) in tumorous mucosa in a gender-independent manner. In females, we observed an ABCC4 downregulation and a PTGS2 mRNA upregulation compared to males in tumoral mucosa (mean factor of 0.61 and 1.64, respectively). We reported dysregulation of the inflammation triggered PGE2 pathway in a Caucasian population with an intermediate risk for GC, which might highlight the applicability of aspirin in the treatment of GC patients.

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 TGFß 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.

The regulatory mechanism involved in the prostaglandin E2 disposition in carbon tetrachloride-induced liver injury.

Prostaglandin E2 (PGE2) exhibits hepatoprotective effects against various types of liver injury. However, there is little information on the disposition of endogenous PGE2 during liver injury. In the present study, we attempted to elucidate the mechanism involved in regulating PGE2 distribution during liver injury. Carbon tetrachloride (CCl4) was used to establish a liver injury mouse model. PGE2 was measured by LC-MS/MS. The plasma and hepatic PGE2 levels were significantly increased at 6 to 48 h after CCl4 treatment. The ratio of plasma levels of 13,14-dihydro-15-ketoPGE2 (PGEM), a major PGE2 metabolite, to PGE2 decreased significantly after CCl4 treatment. PGE2 synthesis and expression of enzymes related to PGE2 production were not induced, while the activity and mRNA expression of 15-prostaglandin dehydrogenase (15-PGDH/Hpgd), a major enzyme for PGE2 inactivation, decreased significantly in the liver of CCl4-treated mice compared to that of vehicle-treated control. The plasma and hepatic PGE2 levels were negatively correlated with the hepatic mRNA expression levels of Hpgd. Although the mRNA expression of organic anion transporting polypeptide 2A1 (OATP2A1/Slco2a1), a major PGE2 transporter, was upregulated, other hepatic OATPs decreased significantly at 24 h after CCl4 treatment. Immunohistochemical analysis indicated that 15-PGDH was mainly expressed in endothelial cells and that OATP2A1 was expressed at least in endothelial cells and Kupffer cells in the liver. These results suggest that the decreased 15-PGDH expression in hepatic endothelial cells is the principal mechanism for the increase in hepatic and plasma PGE2 levels due to the CCl4-induced liver injury.

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

BACKGROUND: 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-ß and microRNA 218. OBJECTIVE: 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. METHODS: In vitro 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 ex vivo 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. RESULTS: 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 in vivo and in vitro. CONCLUSIONS: These findings highlight the role of 15-PGDH in IPF and suggest 15-PGDH inhibition as a promising therapeutic approach.

Possible predisposition for colorectal carcinogenesis due to altered gene expressions in normal appearing mucosa from patients with colorectal neoplasia.

BACKGROUND: Investigations of colorectal carcinogenesis have mainly focused on examining neoplastic tissue. With our aim of identifying potentially cancer-predisposing molecular compositions, we chose a different approach by examining endoscopically normal appearing colonic mucosa of patients with and without colorectal neoplasia (CRN). Directed by this focus, we selected 18 genes that were previously found with altered expression in colorectal cancer affected mucosa. METHODS: Biopsies of colonic mucosa were sampled from 27 patients referred for colonoscopy on suspicion of colorectal disease. Of these, 14 patients had present or previous CRN and the remaining 13 patients served as controls. Using qPCR and Western blot technique, we investigated mRNA and protein expressions. Expressions were investigated for selected kinases in the extracellular signal-regulated kinase/mitogen activated protein kinase (ERK/MAPK), the phosphoinositide 3-kinase/Akt, and the Wnt/ß-catenin pathways as well as for selected phosphatases and several entities associated with prostaglandin E2 (PGE2) signaling. Colonic mucosal contents of PGE2 and PGE2 metabolites were determined by use of ELISA. RESULTS: We found up-regulation of ERK1, ERK2, Akt1, Akt2, PLA2G4A, prostanoid receptor EP3 and phosphatase scaffold subunit PPP2R1B mRNA expression in normal appearing colonic mucosa of CRN patients compared to controls. CONCLUSION: Present study supports that even normal appearing mucosa of CRN patients differs from that of non-CRN patients at a molecular level. Especially expression of ERK1 mRNA was increased (p = 0.007) in CRN group. ERK1 may therefore be considered a potential candidate gene as predictive biomarker for developing CRN. Further validation in larger cohorts are required to determine such predictive use in translational medicine and clinics.

The WNT5A Agonist Foxy5 Reduces the Number of Colonic Cancer Stem Cells in a Xenograft Mouse Model of Human Colonic Cancer.

BACKGROUND: The wingless-type mammary tumour virus integration site 5A (WNT5A) agonist Foxy5 was shown in vitro to affect intracellular signalling implicated in the regulation of colonic cancer stem cells (CSCs). MATERIALS AND METHODS: In order to study whether Foxy5 can modulate CSCs, either HT-29 or Caco-2 human colonic cancer cells, both lacking endogenous WNT5A expression, were inoculated subcutaneously into nude mice. RESULTS: Foxy5 reduced the expression of the stem-cell marker aldehyde dehydrogenase and, interestingly, the specific colon CSC marker double cortin-like kinase 1. Foxy5 also reduced active ß-catenin and the expression of its downstream target Achaete Scute complex homolog 2, a CSC-preserving transcription factor. Foxy5 also reduced cyclo-oxygenase 2 expression, responsible for the formation of the CSC-promoting prostaglandin E2 (PGE2), but increased that of 15-hydroxyprostaglandin dehydrogenase expression, a PGE2-degrading enzyme. Accordingly, Foxy5 impairs both ß-catenin and PGE2 signalling, both of which have been implicated in promoting the niche of colonic CSCs. CONCLUSION: Our data suggest that Foxy5 can complement the traditional adjuvant chemotherapeutic treatment to which CSCs are resistant.