prostaglandin-d2 and Pancreatic-Neoplasms

Development of pancreatic ductal adenocarcinoma (PDA) involves acinar to ductal metaplasia and genesis of tuft cells. It has been a challenge to study these rare cells because of the lack of animal models. We investigated the role of tuft cells in pancreatic tumorigenesis.. We performed studies with LSL-Kras. Pancreata from KC mice had increased formation of tuft cells and higher levels of prostaglandin D. In mice with KRAS-induced pancreatic tumorigenesis, loss of tuft cells accelerates tumorigenesis and increases the severity of caerulein-induced pancreatic injury, via decreased production of prostaglandin D

Topics: Animals; Carcinoma, Pancreatic Ductal; Cell Transformation, Neoplastic; Ceruletide; Disease Models, Animal; Energy Metabolism; Fibrosis; Humans; Interleukins; Intramolecular Oxidoreductases; Mice, Transgenic; Mutation; Octamer Transcription Factors; Pancreas; Pancreatic Neoplasms; Pancreatitis; Prostaglandin D2; Proto-Oncogene Proteins p21(ras); Time Factors; Transcription Factors

Topics: Animals; Cell Transformation, Neoplastic; Mice; Pancreas; Pancreatic Neoplasms; Prostaglandin D2

There is growing evidence that stress-coping mechanisms represent tumor cell vulnerabilities that may function as therapeutically beneficial targets. Recent work has delineated an integrated stress adaptation mechanism that is characterized by the formation of cytoplasmic mRNA and protein foci, termed stress granules (SGs). Here, we demonstrate that SGs are markedly elevated in mutant KRAS cells following exposure to stress-inducing stimuli. The upregulation of SGs by mutant KRAS is dependent on the production of the signaling lipid molecule 15-deoxy-delta 12,14 prostaglandin J2 (15-d-PGJ2) and confers cytoprotection against stress stimuli and chemotherapeutic agents. The secretion of 15-d-PGJ2 by mutant KRAS cells is sufficient to enhance SG formation and stress resistance in cancer cells that are wild-type for KRAS. Our findings identify a mutant KRAS-dependent cell non-autonomous mechanism that may afford the establishment of a stress-resistant niche that encompasses different tumor subclones. These results should inform the design of strategies to eradicate tumor cell communities.

Topics: Adenocarcinoma; Animals; Cell Line, Tumor; Colonic Neoplasms; Cytoplasmic Granules; Drug Resistance, Neoplasm; Eukaryotic Initiation Factor-4A; Female; Heterografts; Humans; Mice; Mutation; Neoplasm Transplantation; Pancreatic Neoplasms; Prostaglandin D2; Proto-Oncogene Proteins p21(ras); Up-Regulation

The pro-inflammatory cytokine IL-1β leads to losses in functional β-cell mass in part by inducing the expression of genes that produce soluble mediators of inflammation, such as cyclooxygenase-2 (COX2). In the current study, we sought to understand what factors control the COX2 gene in response to IL-1β and how prostaglandins downstream of COX2 impact pro-inflammatory gene transcription in pancreatic β-cells. We analyzed COX2 gene expression in response to different maneuvers impacting NF-κB proteins. Also, we report alterations in the expression of COX2, EP-3 and EP-4 receptor genes by PGD(2) and PGE(2). Moreover, we examined whether PGD(2) and PGE(2) regulated NF-κB and interferon-gamma activated sequence (GAS) reporter gene activity. IL-1β-mediated induction of the COX2 gene requires the p65 and p50 subunits of NF-κB. In addition, PGD(2) and PGE(2) coordinately alter COX2 and EP receptor gene expression patterns and potentiate the cytokine-mediated transcriptional activity of promoters containing NF-κB or GAS response elements.

Topics: Animals; Cell Line, Tumor; Cyclooxygenase 2; Dinoprostone; Gene Expression Regulation, Enzymologic; Genes, Reporter; Inflammation Mediators; Insulin-Secreting Cells; Insulinoma; Interleukin-1beta; NF-kappa B p50 Subunit; Pancreatic Neoplasms; Promoter Regions, Genetic; Prostaglandin D2; Prostaglandins; Rats; Receptors, Prostaglandin E, EP3 Subtype; Receptors, Prostaglandin E, EP4 Subtype; Transcription Factor RelA

To study the possible actions and mechanisms of peroxisome proliferator-activated receptor gamma (PPARgamma), a ligand-activated transcription factor, in pancreatic carcinogenesis, especially in angiogenesis.. Expressions of PPARgamma and retinoid acid receptor (RXRalpha) were examined by reverse-transcription polymerase chain reaction (RT-PCR) with immunocytochemical staining. Pancreatic carcinoma cells, PANC-1, were treated either with 9-cis-RA, a ligand of RXRalpha, or with 15-deoxy-Delta(12,14) prostaglandin J(2) (15d-PGJ(2)), a ligand of PPARgamma, or both. Antiproliferative effect was evaluated by cell viability using methyltetrazolium (MTT) assay. A pancreatic carcinoma xenograft tumor model of nude mice was established by inoculating PANC-1 cells subcutaneously. Rosiglitazone, a specific ligand of PPARgamma, was administered via water drinking in experimental group of nude mice. After 75 d, all mice were sacrificed. Expression of proliferating cell nuclear antigen (PCNA) in tumor tissue was examined with immunohistochemical staining. Expression of vascular endothelial growth factor (VEGF) mRNA in PANC-1 cells, which were treated with 15d-PGJ(2) or 9-cis-RA at various concentrations or different duration, was detected by semi-quantitative RT-PCR. Effects of Rosiglitazone on changes of microvascular density (MVD) and VEGF expression were investigated in xenograft tumor tissue. Neovasculature was detected with immunohistochemistry staining labeled with anti-IV collagen antibody, and indicated by MVD.. RT-PCR and immunocytochemical staining showed that PPARgamma and RXRalpha were expressed in PANC-1 cells at both transcription level and translation level. MTT assay demonstrated that 15d-PGJ(2), 9-cis-RA and their combination inhibited the growth of PANC-1 cells in a dose-dependent manner. 9-cis-RA had a combined inhibiting action with 15d-PGJ(2) on the growth of pancreatic carcinoma. In vivo studies revealed that Rosiglitazone significantly suppressed the growth of pancreatic carcinoma as compared to control group (0.48+/-0.23 cm(3) vs 2.488+/-0.59 cm(3), P<0.05), and the growth inhibition rate was 80.7%. Immunohistochemistry study showed that PCNA was down regulated in Rosiglitazone-treated group compared to the control group. 15d-PGJ(2), 9-cis-RA and their combination inhibited the expression of VEGF mRNA in PANC-1 cells in a dose- and time-dependent manner. MVD was decreased more significantly in Rosiglitazone-treated mice (10.67+/-3.07) than in the control group (31.44+/-6.06) (P<0.01). VEGF expression in xenograft tumor tissue was also markedly down-regulated in Rosiglitazone-treated mice.. Activation of PPARgamma inhibits the growth of pancreatic carcinoma both in vitro and in vivo. Suppression of tumor angiogenesis by down-regulating the expression of VEGF may be one of the mechanisms by which PPARgamma activation inhibits the growth of pancreatic carcinoma.

Topics: Animals; Base Sequence; Cell Line, Tumor; Female; Humans; Mice; Mice, Nude; Neovascularization, Pathologic; Pancreatic Neoplasms; PPAR gamma; Prostaglandin D2; Retinoid X Receptor alpha; RNA, Messenger; RNA, Neoplasm; Rosiglitazone; Thiazolidinediones; Transplantation, Heterologous; Tretinoin; Vascular Endothelial Growth Factor A

Peroxisome proliferator-activated receptor-gamma (PPARgamma) ligands have been shown to possess anti-inflammatory properties that include the inhibition of transcription factor activation and the expression of inflammatory genes. Using pancreatic beta-cells, we have shown that PPARgamma ligands such as 15-deoxy-Delta(12,14)-prostaglandin J(2) (PGJ(2)) attenuate interferon-gamma-induced signal transducer and activator of transcription 1 activation and interleukin (IL)-1beta-induced nuclear factor-kappaB activation by a pathway that correlates with endoplasmic reticulum stress and the induction of the unfolded protein response (UPR). The UPR is a conserved cellular response activated by a number of cell stressors and is believed to alleviate the stress and promote cell survival. However, prolonged activation of the UPR results in cellular death by apoptosis. In this report, we have examined the effects of PGJ(2) on UPR activation and the consequences of this activation on cell survival. Consistent with induction of a cell death pathway, treatment of rat islets and RINm5F cells for 24 h with PGJ(2) results in caspase-3 activation and caspase-dependent beta-cell death. The actions of these ligands do not appear to be selective for beta-cells, because PGJ(2) stimulates macrophage apoptosis in a similar fashion. Associated with cell death is the enhanced phosphorylation of eukaryotic initiation factor 2alpha (eIF2alpha), and in cells expressing a mutant of eIF2alpha that cannot be phosphorylated, the stimulatory actions of PGJ(2) on caspase-3 activation are augmented. These findings suggest that, whereas PGJ(2)-induced UPR activation is associated with an inhibition of cytokine signaling, prolonged UPR activation results in cell death, and that eIF2alpha phosphorylation may function in a protective manner to attenuate cell death.

Topics: Animals; Apoptosis; Caspase 3; Cells, Cultured; Enzyme Activation; Eukaryotic Initiation Factor-2; Insulin-Secreting Cells; Insulinoma; Ligands; Macrophages; Male; Mice; Mutation; Pancreatic Neoplasms; Phosphorylation; PPAR gamma; Prostaglandin D2; Protein Folding; Rats; Rats, Sprague-Dawley; Time Factors

The nuclear hormone receptor peroxisome proliferator-activated receptor (PPAR)-gamma plays a role in cancer development in addition to its role in glucose metabolism. The natural ligand of PPAR-gamma, namely, 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), has been shown to possess antineoplastic activity in cancer cells. However, the mechanism underlying its antineoplastic activity remains to be elucidated. Inhibition of the expression of human telomerase reverse transcriptase (hTERT), a major determinant of telomerase activity, reportedly induces rapid apoptosis in cancer cells. In this study, we investigated the effect of 15d-PGJ(2) on hTERT expression. We found that 15d-PGJ(2) induced apoptosis in the MIAPaCa-2 pancreatic cancer cells and dose-dependently decreased hTERT mRNA and protein expression. Down-regulation of hTERT expression by hTERT-specific small inhibitory RNA also induced apoptosis. Furthermore, 15d-PGJ(2) attenuated the DNA binding of estrogen receptor (ER). MIAPaCa-2 expressed only ERbeta, and although its expression did not decrease due to 15d-PGJ(2), its phosphorylation was suppressed. Additionally, a mitogen-activated protein kinase (MAPK) kinase inhibitor decreased ERbeta phosphorylation, and 15d-PGJ(2) attenuated MAPK activity. We conclude that hTERT down-regulation by 15d-PGJ(2) plays an important role in the proapoptotic property of the latter. Furthermore, 15d-PGJ(2) inhibits ERbeta-mediated hTERT gene transcription by suppressing ERbeta phosphorylation via the inhibition of MAP kinase signaling.

Topics: Apoptosis; Cell Line, Tumor; DNA, Neoplasm; Down-Regulation; Estrogen Receptor beta; Gene Expression Regulation, Neoplastic; Humans; MAP Kinase Signaling System; Pancreatic Neoplasms; Phosphoprotein Phosphatases; Phosphorylation; Phosphoserine; Promoter Regions, Genetic; Prostaglandin D2; Protein Binding; RNA, Small Interfering; Telomerase; Transcription, Genetic

Cancer cell invasion and metastasis require the concerted action of several proteases that degrade extracellular matrix proteins and basement membranes. Recent reports suggest the plasminogen activator system plays a critical role in pancreatic cancer biology. In the present study, we determined the contribution of the plasminogen activator system to pancreatic cancer cell invasion in vitro. Moreover, the effect of peroxisome proliferator-activated receptor (PPAR)-gamma ligands, which are currently in clinical use as antidiabetic drugs and interestingly seem to display antitumor activities, on pancreatic cancer cell invasion and the plasminogen activator system was assessed. Expression of components of the plasminogen activator system [i.e., urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor-1, and uPA receptor] was detected in six human pancreatic cancer cell lines. Inhibition of urokinase activity by specific synthetic compounds reduced baseline pancreatic cancer cell invasion. The PPAR-gamma ligands 15-deoxy-Delta12,14-prostaglandin J2 and ciglitazone also attenuated pancreatic cancer cell invasion. This effect was abrogated by dominant-negative PPAR-gamma receptors and pharmacologic PPAR-gamma inhibitors. Moreover, activation of PPAR-gamma by ligands increased plasminogen activator inhibitor-1 and decreased uPA levels in pancreatic cancer cells, and this was accompanied by a reduction in total urokinase activity. The present study shows that the plasminogen activator system plays an integral role in pancreatic cancer cell invasion in vitro. Activation of the nuclear receptor PPAR-gamma by ligands reduced pancreatic cancer cell invasion, which was largely mediated by modulation of the plasminogen activator system. These findings further underscore the potential role of PPAR-gamma ligands as therapeutic agents in pancreatic cancer.

Topics: Cell Line, Tumor; Down-Regulation; Humans; Ligands; Neoplasm Invasiveness; Pancreatic Neoplasms; Plasminogen Activator Inhibitor 1; PPAR gamma; Prostaglandin D2; Thiazolidinediones; Up-Regulation; Urokinase-Type Plasminogen Activator

We have previously reported that 15-deoxy-delta-prostaglandin J2 (15d-PGJ2), a potent ligand for peroxisome proliferator-activated receptor gamma (PPARgamma), induces caspase-mediated apoptosis in human pancreatic cancer cell lines. Mitogen-activated protein kinases (MAPKs) are known to regulate apoptosis in various cancers. The purpose of this study was to investigate the role of MAPKs (ERK, JNK, and p38) in 15d-PGJ2-induced pancreatic cancer cell apoptosis.. The effect of 15d-PGJ2 on MAPK activity was investigated by kinase assays using the human pancreatic cancer cell line MIA PaCa-2. Western blot analysis was performed to analyze phosphorylation of MAPKs, activation of caspases and poly ADP-ribose polymerase (PARP) cleavage. Apoptosis was evaluated by caspase-3 enzymatic activity and DNA fragmentation assay.. 15d-PGJ2 activated all 3 MAPKs in a dose- and time-dependent fashion. SB202190, an inhibitor of p38, prevented 15d-PGJ2-induced activation of caspase-8, -9, and -3 and significantly decreased apoptosis. This effect was potentiated by SP600125, an inhibitor of JNK, although SP600125 alone had no significant effect on 15d-PGJ2-induced apoptosis. In contrast, PD98059, an inhibitor of MEK, significantly increased sensitivity to 15d-PGJ2-induced apoptosis.. 15d-PGJ2 stimulates proapoptotic and antiapoptotic MAPK pathways. Sensitivity to 15d-PGJ2-induced apoptosis is increased by ERK inhibition but decreased by inhibition of p38.

Topics: Antineoplastic Agents; Apoptosis; Caspases; Cell Line, Tumor; Enzyme Activation; Humans; Ligands; Mitogen-Activated Protein Kinases; Pancreatic Neoplasms; PPAR gamma; Prostaglandin D2

The PI3K pathway contributes to the invasive properties and apoptosis resistance that epitomize pancreatic cancers. PPARgamma is a ligand-activated transcription factor with anti-inflammatory and anti-tumor effects; the mechanisms of tumor suppression are unknown. The purpose of this study was to examine whether activation of PPARgamma can increase the expression of the tumor suppressor PTEN and inhibit PI3K activity. AsPC-1 human pancreatic cancer cells, transfected with a PPRE-luciferase construct, demonstrated increased luminescence following treatment with PPARgamma ligands, indicating the presence of functional PPARgamma protein. The selective PPARgamma ligand rosiglitazone increased PTEN expression in AsPC-1 cells; concurrent treatment with GW9662, which inhibits PPARgamma activation, prevented the increase in PTEN protein levels. Levels of phosphorylated Akt decreased as PTEN levels increased, indicating inhibition of PI3K activity. Taken together, our results suggest that activation of PPARgamma may represent a novel approach for the treatment of pancreatic cancer by increasing PTEN levels and inhibiting PI3K activity.

Topics: DNA-Binding Proteins; Genes, Reporter; Humans; Ligands; Nuclear Proteins; Pancreatic Neoplasms; Phosphatidylinositol 3-Kinases; Phosphoric Monoester Hydrolases; Prostaglandin D2; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Receptors, Cytoplasmic and Nuclear; Recombinant Fusion Proteins; Repressor Proteins; Thiazoles; Thiazolidinediones; Transcription Factors; Tumor Cells, Cultured; Tumor Suppressor Proteins

PPARgamma is a ligand-activated transcription factor with antitumor effects; its ability to inhibit pancreatic cancer invasion is unknown. The purpose of this study was to define the inhibitory effect of PPARgamma ligands on pancreatic cancer invasion and the expression of invasion-related genes.. Western blotting was used to establish expression of PPARgamma in AsPC-1 and SUIT-2 cells. AsPC-1 cells were treated with nontoxic doses of PPARgamma ligands (15d-PGJ(2), troglitazone, or rosiglitazone) and Matrigel Invasion chambers were used to assess invasion in vitro. A microarray for genes that contribute to invasion was used to investigate the antiinvasive targets of PPARgamma. Gene array results were confirmed by use of ribonuclease protection assay or Northern blotting.. Rosiglitazone and 15d-PGJ(2) decreased AsPC-1 cell invasion; GW9662, which inhibits PPARgamma, reversed this effect. The expression of tissue plasminogen activator (tPA) was decreased by rosiglitazone treatment, which was confirmed by Northern blotting. Secreted levels of tPA in AsPC-1 conditioned media were also decreased.. We demonstrate, for the first time, that secretion of the invasive factor tPA was decreased by rosiglitazone treatment in AsPC-1 cells. PPARgamma ligands inhibit pancreatic cancer cell invasion, suggesting that these agents may represent novel strategies to treat pancreatic cancer.

Topics: Chromans; Humans; Integrins; Matrix Metalloproteinase Inhibitors; Neoplasm Invasiveness; Pancreatic Neoplasms; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Rosiglitazone; Thiazoles; Thiazolidinediones; Tissue Plasminogen Activator; Transcription Factors; Troglitazone; Tumor Cells, Cultured

Arachidonic acid metabolites known to affect platelet function also interfere with tumor growth and metastases. The purpose of this study was to evaluate the anti-metastatic potential of ketoconazole, a thromboxane synthetase and 5-lipoxygenase inhibitor, on hepatic metastasis from a human pancreatic adenocarcinoma in nude mice and its effect on serum prostaglandin levels.. The human pancreatic tumor cells (RWP-2) were injected intrasplenically in nude mice grouped into control, ketoconazole (270 microg), ketoconazole (360 microg), and ketoconazole (540 microg). The agent was administered intraperitoneally 30 min before and every 24 h after the tumor cell inoculation for 8 days. In a separate experiment thromboxane B2 (TxB2), prostaglandin D2 (PGD2), prostaglandin E2 (PGE2) and 6-Keto-F1a (stable prostacyclin derivative) were measured on blood from controls, tumor bearing animals and animals bearing tumors treated with 270 microg of ketoconazole.. Statistically significant differences were observed between the control and three-treatment groups on the reduction of liver tumor nodules (p < 0.001), and in the liver surface areas occupied by tumor (p < 0.001). The TxB2 levels decreased from 150.6 ng/mL in the tumor bearing to 104.8 ng/mL in the ketoconazole treated animals (p < 0.05). PGD2, PGE2 and 6-keto-F1a levels increased to 7.1 ng/mL, 8.3 ng/mL, and 13.6 ng/mL from 3 ng/mL, 5.8 ng/mL, and 0.02 ng/mL respectively (p < 0.001).. These results indicate that ketoconazole significantly reduced hepatic metastases from the human pancreatic carcinoma RWP-2 in the nude mouse model, and inhibited thromboxane B2 formation, potentiating a concomitant redirection of platelet endoperoxide metabolism into PGD2, PGE2, and 6-keto-F1a. It is hypothesized that the changes in the arachidonic acid metabolism mediate the ameliorating effect of ketoconazole on experimental hepatic metastasis.

Topics: 6-Ketoprostaglandin F1 alpha; Adenocarcinoma; Animals; Antineoplastic Agents; Dinoprostone; Humans; Injections, Intraperitoneal; Ketoconazole; Liver Neoplasms; Mice; Mice, Nude; Neoplasm Metastasis; Pancreatic Neoplasms; Prostaglandin Antagonists; Prostaglandin D2; Prostaglandins; Thromboxane B2; Tumor Cells, Cultured; Xenograft Model Antitumor Assays

Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed in certain human cancers; ligand-induced PPARgamma activation can result in growth inhibition and differentiation in these cells. However, the precise mechanism for the antiproliferative effect of PPARgamma ligands is not entirely known.. The purpose of this study was to examine the effect of PPARgamma ligands on pancreatic cancer cell growth and invasiveness.. The effect of two PPARgamma ligands, 15 deoxy-delta12,14 prostaglandin J2 (15d-PGJ2) and ciglitazone, on the growth of four human pancreatic cancer cell lines (BxPC-3, MIA PaCa-2, Panc-1, and L3.6) was assessed. Expression of cell-cycle and apoptotic-related proteins was measured. Finally, the effect of 15d-PGJ2 on pancreatic cancer cell invasiveness and matrix metalloproteinase expression was determined.. Both 15d-PGJ2 and ciglitazone inhibited the growth of all four pancreatic cancer cell lines in a dose- and time-dependent fashion. Treatment of BxPC-3 cells with 15d-PGJ2 resulted in a time-dependent decrease in cyclin D1 expression associated with a concomitant induction of p21waf1 and p27kip1. In addition, 15d-PGJ2 treatment induced apoptosis through activation of caspase-8, -9, and -3. Moreover, pancreatic cancer cell invasiveness was significantly suppressed after treatment with a nontoxic dose of 15d-PGJ2, which was associated with a reduction of MMP-2 and MMP-9 protein levels and activity.. These results demonstrate that PPARgamma ligands have the dual advantage of inhibiting pancreatic cancer cell growth while reducing the invasiveness of the tumor cells, suggesting a potential role for these agents in the adjuvant treatment of pancreatic cancer.

Topics: 3T3 Cells; Adenocarcinoma; alpha Catenin; Animals; Antineoplastic Agents; Apoptosis; beta Catenin; Cadherins; Caspase 3; Caspase 8; Caspase 9; Caspases; Cell Cycle; Cell Cycle Proteins; Cell Division; Collagen; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinase Inhibitor p27; Cyclins; Cyclooxygenase 2; Cytoskeletal Proteins; Drug Combinations; Enzyme Induction; Gene Expression Regulation, Neoplastic; Humans; Isoenzymes; Laminin; Ligands; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Membrane Proteins; Mice; Neoplasm Invasiveness; Neoplasm Proteins; Pancreatic Neoplasms; Prostaglandin D2; Prostaglandin-Endoperoxide Synthases; Proteoglycans; Receptors, Cytoplasmic and Nuclear; Thiazoles; Thiazolidinediones; Trans-Activators; Transcription Factors; Tumor Cells, Cultured; Tumor Suppressor Proteins

Topics: Adenocarcinoma; Aged; Aged, 80 and over; Blood Platelet Disorders; Blood Platelets; Female; Humans; Myeloproliferative Disorders; Pancreatic Neoplasms; Platelet Aggregation; Prostaglandin D2; Prostaglandins D