prostaglandin-d2 and Carcinoma--Squamous-Cell

Peroxisome proliferator-activated receptor-gamma (PPAR-γ) activators have anti-cancer effects. Our objective was to determine the effect of PPAR-γ ligands 15-deoxy-D. NA and CA9-22 cells were treated in vitro with 15-PGJ. MTT assays demonstrated dose-dependent decreases after 15-PGJ. Our results suggest these agents, in addition to activating PPAR-γ, can downregulate NF-κB and potentiate apoptosis in oral cancer cells.

Topics: Carcinoma, Squamous Cell; Cell Line; Humans; Mouth Neoplasms; PPAR gamma; Prostaglandin D2

Aldo-keto reductase 1C3 (AKR1C3) is an enzyme involved in metabolizing prostaglandins (PGs) and sex hormones. It metabolizes PGD2 to 9α11β-PGF2 , diverting the spontaneous conversion of PGD2 to the PPARγ agonist, 15-Deoxy-Delta-12, 14-prostaglandin J2 (15d-PGJ2 ). AKR1C3 is overexpressed in various malignancies, suggesting a tumor promoting function. This work investigates AKR1C3 expression in human non-melanoma skin cancers, revealing overexpression in squamous cell carcinoma (SCC). Effects of AKR1C3 overexpression were then evaluated using three SCC cell lines. AKR1C3 was detected in all SCC cell lines and its expression was upregulated in response to its substrate, PGD2 . Although attenuating AKR1C3 expression in SCC cells by siRNA did not affect growth, treatment with PGD2 and its dehydration metabolite, 15d-PGJ2 , decreased SCC proliferation in a PPARγ-dependent manner. In addition, treatment with the PPARγ agonist pioglitazone profoundly inhibited SCC proliferation. Finally, we generated an SCC cell line that stably overexpressed AKR1C3 (SCC-AKR1C3). SCC-AKR1C3 metabolized PGD2 to 9α11β-PGF2 12-fold faster than the parent cell line and was protected from the antiproliferative effect mediated by PGD2 . This work suggests that PGD2 and its metabolite 15d-PGJ2 attenuate SCC proliferation in a PPARγ-dependent manner, therefore activation of PPARγ by agonists such as pioglitazone may benefit those at high risk of SCC.

Topics: 3-Hydroxysteroid Dehydrogenases; Aldo-Keto Reductase Family 1 Member C3; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Gene Expression Regulation, Neoplastic; Humans; Hydroxyprostaglandin Dehydrogenases; PPAR gamma; Prostaglandin D2; Prostaglandins; RNA, Small Interfering; Skin; Skin Neoplasms; Up-Regulation

Peroxisome proliferator-activated receptor-gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, is involved in suppressing the growth of several tumors. We showed that PPAR-gamma is expressed in Barrett's adenocarcinoma cell lines and inhibited the growth of these lines through the induction of G1 cell cycle arrest and apoptosis. We examined PPAR-gamma expression in human esophageal squamous cell carcinoma (SCC) in vitro and in vivo and investigated whether PPAR-gamma ligands affect the proliferation and apoptosis of human SCC cell lines. Biopsy specimens (n=46) obtained from human SCC of the esophagus were stained using a monoclonal antibody against human PPAR-gamma. We assessed the effects of PPAR-gamma ligands on the growth of SCC cells by adding 15-deoxy prostaglandin J2 (15d-PGJ2), or troglitazone to six human esophageal SCC cell lines (TE-1, TE-2, TE-3, TE-5, TE-8, and TE-9). Immunohistochemical staining showed that 34 of 46 (73.9%) SCC of the esophagus expressed PPAR-gamma. All SCC cell lines expressed PPAR-gamma mRNA and protein, especially when poorly differentiated (TE-2, TE-5, and TE-9). The PPAR-gamma ligands significantly and dose-dependently inhibited the proliferation of SCC lines, except for well-differentiated TE-1 and TE-3. Apoptosis was induced by 15d-PGJ2 (10 microM) in all tested SCC lines except TE-1, whereas troglitazone (50 microM) was marginally effective in only the TE-2 and TE-3 cell lines. The present findings suggest that PPAR-gamma could be a therapeutic target for treating squamous cell carcinoma of the esophagus, possibly through the induction of apoptosis.

Topics: Antibodies, Monoclonal; Apoptosis; Barrett Esophagus; Biopsy; Bisbenzimidazole; Blotting, Western; Carcinoma, Squamous Cell; Caspase 3; Caspases; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Chromans; Dose-Response Relationship, Drug; Esophageal Neoplasms; G1 Phase; Humans; Immunohistochemistry; Ligands; PPAR gamma; Prostaglandin D2; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Messenger; Thiazolidinediones; Thymidine; Troglitazone

Antineoplastic properties of cyclopentenone 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2) involve peroxisome proliferator-activated receptor gamma (PPARgamma) dependent and independent mechanisms. We recently reported that 15d-PGJ2 inhibits cell growth and induces apoptosis in human oral squamous cell carcinoma (SCC) partly independent of PPARgamma activation. Given the importance of epidermal growth factor receptor (EGFR) as a therapeutic target in head and neck SCC, we addressed the effects of 15d-PGJ2 on EGFR expression. 15d-PGJ2, but not other PPARgamma ligands, abrogated EGFR protein expression in oral SCC cells. 15d-PGJ2 also decreased EGFR mRNA, indicating downmodulation at the transcriptional level. Moreover, treatment with 9,10-dihydro-15d-PGJ2, a 15d-PGJ2 analog lacking the reactive carbonyl group, failed to effect EGFR expression. These findings provide evidence for EGFR downregulation in oral SCC cells through a novel anticancer effect of 15d-PGJ2 that is attributed to the reactive cyclopentenone ring system.

Topics: Carcinoma, Squamous Cell; Cell Line, Tumor; Cyclopentanes; ErbB Receptors; Humans; Mouth Neoplasms; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Transcription Factors

Cyclopentenone 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) exerts antineoplastic effects on various types of human cancer. We recently showed that treatment with 15d-PGJ(2) induces apoptosis accompanied by downregulation of the oncogenic signal transducer and activator of transcription 3 (Stat3) signalling in human oral squamous cell carcinoma (SCC) cells. The current study examines the effects of 15d-PGJ(2) on the epidermal growth factor receptor (EGFR) and Janus Kinase (JAK)-mediated signalling pathways. Inhibition of Stat3 by 15d-PGJ(2) was abolished by exogenous stimulation with transforming growth factor alpha (TGF-alpha), but not interleukin 6 (IL-6), supporting a selective effect of 15d-PGJ(2) on IL-6-mediated signalling. Importantly, 15d-PGJ(2) selectively abrogated constitutive and IL-6-mediated JAK phosphorylation without affecting EGFR-activated levels. Moreover, the inhibitory effect of 15d-PGJ(2) on JAK signalling required the reactive alpha,beta-unsaturated carbon within the cyclopentenone ring. Targeting of JAK signalling using a specific JAK inhibitor also abolished Stat3 phosphorylation and resulted in apoptosis in oral SCC cells. Our findings provide the first evidence for 15d-PGJ(2)-mediated downregulation of constitutive and IL-6-induced JAK signalling in cancer and support that JAK inhibition and suppression of EGFR-independent Stat3 activation by 15d-PGJ(2) represent a promising approach for induction of apoptosis in oral SCC cells.

Topics: Apoptosis; Carcinoma, Squamous Cell; Cell Division; Cell Line, Tumor; ErbB Receptors; Humans; Interleukin-6; Janus Kinase 1; Mouth Neoplasms; Prostaglandin D2; Protein-Tyrosine Kinases; Signal Transduction

15-deoxy-Delta(12,14)-prostaglandin J(2) (15-d-PGJ(2)) and troglitazone have been shown to induce apoptosis in several carcinoma cell lines. However, apoptotic signaling pathways of these agents are poorly understood. We tested the hypothesis that peroxisome proliferator-activated receptor-gamma ligands such as these two agents will induce caspase-mediated apoptosis in human oral squamous cell carcinomas (SCC). Treatment of these cell lines with 15-d-PGJ(2) or troglitazone decreased cell viability in a time- and dose-dependent manner. 15-d-PGJ(2), but not troglitazone, induced apoptosis, and this effect was time-dependent. Exposure of cells to 20 micro M of 15-d-PGJ(2) initiated early cytochrome c release, followed by late caspase activation. Furthermore, co-treatment with caspase inhibitors such as Z-VAD-FMK or Z-DEVD-FMK of oral SCC cells that had been treated with 20 micro M of 15-d-PGJ(2) blocked apoptosis. Our study demonstrates that treatment with 15-d-PGJ(2), but not troglitazone, induces apoptosis in human SCC cell lines, and 15-d-PGJ(2) appears to work through cytochrome c release and caspase activation.

Topics: Amino Acid Chloromethyl Ketones; Analysis of Variance; Antineoplastic Agents; Apoptosis; Carcinoma, Squamous Cell; Caspase Inhibitors; Caspases; Cell Survival; Chromans; Cysteine Proteinase Inhibitors; Cytochrome c Group; Dose-Response Relationship, Drug; Enzyme Activation; Humans; Immunologic Factors; Mouth Neoplasms; Oligopeptides; Prostaglandin D2; Signal Transduction; Thiazoles; Thiazolidinediones; Time Factors; Troglitazone; Tumor Cells, Cultured

Activation of peroxisome proliferator-activated receptor gamma (PPARgamma) has been linked to induction of differentiation, cell growth inhibition and apoptosis in several types of human cancer. However, the possible effects of PPARgamma agonists on human oral squamous cell carcinoma have not yet been reported. In this study, treatment with 15-deoxy-Delta(12,14)-PGJ(2) (15-PGJ(2)), a natural PPARgamma ligand, induced a significant reduction of oral squamous cell carcinoma cell growth, which was mainly attributed to upregulation of apoptosis. Interestingly, rosiglitazone and ciglitazone, two members of the thiazolidinedione family of PPARgamma activators, did not exert a growth inhibitory effect. Given the critical role that the oncogene signal transducer and activator of transcription 3 (Stat3) plays in head and neck carcinogenesis, its potential regulation by PPARgamma ligands was also examined. Treatment of oral squamous cell carcinoma cells with 15-PGJ(2) induced an initial reduction and eventual elimination of both phosphorylated and unphosphorylated Stat3 protein levels. In contrast, other PPARgamma did not induce similar effects. Our results provide the first evidence of significant antineoplastic effects of 15-PGJ(2) on human oral squamous cell carcinoma cells, which may be related to downmodulation of Stat3 and are at least partly mediated through PPARgamma-independent events.

Topics: Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; DNA Primers; DNA-Binding Proteins; Down-Regulation; Humans; Immunoenzyme Techniques; Immunologic Factors; Mouth Neoplasms; Phosphorylation; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; STAT3 Transcription Factor; Thiazoles; Thiazolidinediones; Trans-Activators; Transcription Factors; Tumor Cells, Cultured

Peroxisome proliferator-activated receptor gamma (PPAR-gamma), a member of the nuclear hormone receptor superfamily, is involved in suppression of growth of several types of tumors such as liposarcoma, breast cancer, prostate cancer, and colon cancer, possibly through induction of cell cycle arrest and/or apoptosis. In this study, we demonstrated expression of PPAR-gamma mRNA and protein in human esophageal carcinoma cells. Expression of PPAR-gamma protein was higher in an adenocarcinoma cell line (TE-7 cells) than in a squamous cell carcinoma cell line (TE-1 cells). PPAR-gamma ligands such as 15-deoxy-Delta12,14-prostaglandin J2 and troglitazone significantly inhibited the growth of TE-7 cells but had less or no effect on growth of TE-1 cells. 15d-PGJ2 and troglitazone induced apoptosis in TE-7 cells but not in TE-1 cells. Troglitazone caused G1 cell cycle arrest and reduced ornithine decarboxylase activity (ODC) in TE-7 cells but not in TE-1 cells. Inhibition by PPAR-gamma ligands of growth of esophageal adenocarcinoma cells may thus be due to induction of apoptosis, G1 cell cycle arrest and reduction of ODC activity.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Blotting, Western; Carcinoma, Squamous Cell; Cell Cycle; Cell Division; Chromans; DNA Primers; Esophageal Neoplasms; Flow Cytometry; Humans; Immunologic Factors; Ligands; Ornithine Decarboxylase; Prostaglandin D2; Receptors, Cytoplasmic and Nuclear; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tetrazolium Salts; Thiazoles; Thiazolidinediones; Thymidine; Transcription Factors; Troglitazone; Tumor Cells, Cultured

Four cyclopentenone prostaglandins (CPPGs) and PGE2 caused significant dose-dependent inhibition in growth of human oral squamous carcinoma cells (SCC-15). The rank order of their potency was PGJ2>PGA1>16, 16-dimethyl PGA1>PGA2>PGE2. In a follow-up experiment it was found that the mean per cent inhibition in cell growth by PGJ2 and delta12-PGJ2 at 10(-5) M was 61.22 and 63.81, while that of 5-fluorouracil and methotrexate was 36.67 and 38.86, respectively. delta12-PGJ2 and PGJ2 induced significant dose-dependent inhibition in nuclear DNA synthesis (i.e. cell proliferation). Combining vitamin E succinate with lower concentrations of CPPGs enhanced significantly their inhibitory effect on nuclear DNA synthesis of cancer cells.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Division; Dinoprostone; Fluorouracil; Humans; Methotrexate; Mouth Neoplasms; Prostaglandin D2; Prostaglandins A; Prostaglandins A, Synthetic; Prostaglandins, Synthetic; Tocopherols; Tumor Cells, Cultured; Vitamin E

The cyclopentenone prostaglandins (PGs), such as delta 12-PGJ2 and PGA1, are potent inhibitors of growth in a variety of cultured cells, including human epidermal cells. To clarify the mechanism of the cytotoxicity of these PGs, we examined the effects of delta 12-PGJ2 on the function and expression of E-cadherin, which plays a major role in the maintenance of intercellular adhesion, in transformed human epidermal cells in culture (HSC-1). A 12-h incubation with 5 micrograms/ml of delta 12-PGJ2 did not affect the cell-binding activity of E-cadherin expressed in HSC-1 cells. Immunoblot analysis using a monoclonal antibody specific to human E-cadherin revealed that a 12-h incubation with 5 micrograms/ml of delta 12-PGJ2 induced E-cadherin expression in HSC-1 cells. Immunofluorescence using a monoclonal antibody against human E-cadherin demonstrated that E-cadherin was localized to the cell-cell contact regions in HSC-1 cells. Following a 12-h incubation with 5 micrograms/ml of delta 12-PGJ2, E-cadherin was also detected in a uniform pattern along cell junctions, although cell morphology was changed by the presence of cytotoxic PGs. These results suggest that the cytotoxicity of cyclopentenone PGs is related, at least in part, to E-cadherin expression in transformed human epidermal cells.

Topics: Antibodies, Monoclonal; Cadherins; Carcinoma, Squamous Cell; Cell Communication; Epidermis; Fluorescent Antibody Technique; Humans; Immunoblotting; Prostaglandin D2; Tumor Cells, Cultured

Previous studies have shown that prostaglandin E2 (PGE2) and vitamin E succinate can act in an additive manner to inhibit the proliferation of human oral squamous carcinoma cells (SCC-25). The initial studies on the additive anticancer activity of PGE2 and vitamin E succinate have been extended to include antineoplastic PGs, delta 12-PGJ2 and PGJ2. Treatment of oral squamous carcinoma cells (SCC-15) with delta 12-PGJ2, PGJ2, and vitamin E succinate, individually, caused significant concentration-dependent inhibition of cell proliferation to various degrees. PGJ2 was most potent and caused an inhibition that corresponded to 85.55% at 10(-5) M. Addition of 1 microM of vitamin E succinate to delta 12-PGJ2 or PGJ2 resulted in a significant increase in the inhibitory potency of the lower concentrations of the two PGs. These results suggest a novel role for a mixture of PGs and vitamin E as potent antitumor proliferative agents.

Topics: Antineoplastic Agents; Carcinoma, Squamous Cell; Cell Division; Dinoprostone; Drug Synergism; Humans; Male; Middle Aged; Mouth Neoplasms; Prostaglandin D2; Prostaglandins; Tocopherols; Vitamin E