Biomedical subjects

A J Dannenberg

Publications and source records attributed to A J Dannenberg.

At least 37 records · Page 2Linked to original sources

PubMed2001

Inducible microsomal prostaglandin E synthase is overexpressed in colorectal adenomas and cancer.

Recently, an inducible microsomal human prostaglandin E synthase (mPGES) was identified. This enzyme converts the cyclooxygenase (COX) product prostaglandin (PG) H(2) to PGE(2), an eicosanoid that has been linked to carcinogenesis. Increased amounts of PGE(2) have been observed in many tumor types including colorectal adenomas and cancers. To further elucidate the mechanism responsible for increased levels of PGE(2) in colorectal tumors, we determined the amounts of mPGES and COX-2 in 18 paired samples (tumor and adjacent normal) of colorectal cancer. With immunoblot analysis, mPGES was overexpressed in 83% of colorectal cancers. COX-2 was also commonly up-regulated in these tumors; marked differences in the extent of up-regulation of mPGES and COX-2 were observed in individual tumors. Immunohistochemistry revealed increased mPGES immunoreactivity in neoplastic cells in both colorectal adenomas and cancers compared with adjacent normal colonic epithelium. Cell culture was used to investigate the regulation of mPGES and COX-2. Chenodeoxycholate markedly induced COX-2 but not mPGES in colorectal cancer cells. Tumor necrosis factor-alpha induced both mPGES and COX-2, but the time course and magnitude of induction differed. As reported previously for COX-2, overexpressing Ras caused a several-fold increase in mPGES promoter activity. Taken together, our results suggest that overexpression of mPGES in addition to COX-2 contributes to increased amounts of PGE(2) in colorectal adenomas and cancer. The mechanisms controlling the expression of these two enzymes are not identical.

Adenocarcinoma↗

PubMed2000

COX-2 is expressed in human pulmonary, colonic, and mammary tumors.

BACKGROUND: The cyclooxygenase (COX) enzyme catalyzes the formation of prostaglandins, which can affect cell proliferation and alter the response of the immune system to malignant cells. The inducible form of COX, COX-2, has been shown to be important in carcinogenesis. METHODS: The authors studied COX-1 and -2 expression in 20 tumors of the lung, colon, and breast (60 total) by using commercially available monoclonal and polyclonal antibodies on formalin fixed, paraffin embedded tissue. Our evaluation also included seven carcinoma-associated colonic adenomas and 10 mammary ductal carcinomas in situ (DCIS). Quantitation of immunoreactivity was accomplished using an immunohistochemical scoring system that approximates the use of image analysis-based systems. RESULTS: Ninety percent of lung tumors (squamous cell carcinomas and adenocarcinomas), 71% of colon adenocarcinomas and 56% of breast tumors (DCIS and infiltrating ductal and lobular carcinomas) expressed COX-2 at a moderate to strong level, which was significantly different from the negligible expression in distant nonneoplastic epithelium (controls; P < 0.0001). Poorly differentiated histologic features were correlated with low COX-2 expression overall, especially in colon carcinomas. Among breast carcinomas, DCIS was more likely to express COX-2 than invasive carcinomas. Adenomatous colonic epithelium showed moderate COX-2 expression, as did adjacent nonneoplastic epithelium. COX-1 immunoreactivity was essentially weak to moderate in all tissues evaluated. CONCLUSIONS: COX-2 expression is upregulated in well and moderately differentiated carcinomas of the lung, colon, and breast whereas COX-1 appears to be constitutively expressed at low levels. A possible COX-2 paracrine effect is suggested by moderate immunoreactivity in adjacent nonneoplastic epithelium.

Breast↗

PubMed2000

Ethanol and arachidonic acid increase alpha 2(I) collagen expression in rat hepatic stellate cells overexpressing cytochrome P450 2E1. Role of H2O2 and cyclooxygenase-2.

The ability of ethanol and arachidonic acid (AA), as inducers of oxidative stress and key factors in alcoholic liver disease, to up-regulate alpha 2 collagen type I (COL1A2) gene expression was studied in a hepatic stellate cell line overexpressing the ethanol-inducible cytochrome P450 2E1 (CYP2E1) (E5 cells). A time- and dose-dependent induction in COL1A2 mRNA by ethanol or AA was observed that was prevented by diallylsulfide, a CYP2E1 inhibitor. Nuclear run-on experiments showed transcriptional activation of the COL1A2 gene by ethanol and AA. Catalase abrogated the increase in COL1A2 mRNA suggesting an H(2)O(2)-dependent mechanism. Cyclooxygenase-2 (COX-2) levels and production of prostaglandin E(2) upon addition of AA were elevated in the E5 cells. Incubation with NS-398, a COX-2 inhibitor, blocked the effect of AA, but not of ethanol, on COL1A2 expression suggesting that CYP2E1 activates COX-2 expression, and the oxidation of AA by COX-2 is responsible for the increase in COL1A2. Activity of a reporter construct driven by -378 base pairs of the proximal promoter region of the COL1A2 gene increased in E5 but not control cells and was further increased by ethanol or AA. These experiments link CYP2E1-dependent oxidative stress to induction of COX-2 and the actions of ethanol and AA on activation of collagen gene expression in hepatic stellate cells.

Allyl Compounds↗

PubMed2000

Microtubule-interfering agents stimulate the transcription of cyclooxygenase-2. Evidence for involvement of ERK1/2 AND p38 mitogen-activated protein kinase pathways.

We investigated whether microtubule-interfering agents (MIAs: taxol, colchicine, nocodazole, vinblastine, vincristine, 17-beta-estradiol, 2-methoxyestradiol) altered cyclooxygenase-2 (COX-2) expression in human mammary epithelial cells. MIAs enhanced prostaglandin E(2) synthesis and increased levels of COX-2 protein and mRNA. Nuclear run-off assays revealed increased rates of COX-2 transcription after treatment with MIAs. Calphostin C, an inhibitor of protein kinase C, blocked the induction of COX-2 by MIAs. The stimulation of COX-2 promoter activity by MIAs was inhibited by overexpressing dominant negative forms of Rho and Raf-1. MIAs stimulated ERK, JNK, and p38 mitogen-activated protein kinases (MAPK); pharmacological inhibitors of MAPK kinase and p38 MAPK blocked the induction of COX-2 by MIAs. Overexpressing dominant negative forms of ERK1 or p38 MAPK inhibited MIA-mediated activation of the COX-2 promoter. MIAs stimulated the binding of the activator protein-1 transcription factor complex to the cyclic AMP response element in the COX-2 promoter. A dominant negative form of c-Jun inhibited the activation of the COX-2 promoter by MIAs. Additionally, cytochalasin D, an agent that inhibits actin polymerization, stimulated COX-2 transcription by the same signaling pathway as MIAs. Thus, microtubule- or actin-interfering agents stimulated MAPK signaling and activator protein-1 activity. This led, in turn, to induction of COX-2 gene expression via the cyclic AMP response element site in the COX-2 promoter.

2-Methoxyestradiol↗

PubMed2000

Ursolic acid inhibits cyclooxygenase-2 transcription in human mammary epithelial cells.

We investigated the effects of ursolic acid, a chemopreventive agent, on the expression of cyclooxygenase-2 (COX-2) in phorbol 12-myristate 13-acetate (PMA)-treated human mammary and oral epithelial cells. Treatment with ursolic acid suppressed PMA-mediated induction of COX-2 protein and synthesis of prostaglandin E2. Ursolic acid also suppressed the induction of COX-2 mRNA by PMA. Nuclear run-offs revealed increased rates of COX-2 transcription after treatment with PMA, an effect that was inhibited by ursolic acid. Transient transfections indicated that the effects of PMA were mediated by a cyclic AMP response element in the COX-2 promoter. Ursolic acid inhibited PMA-mediated activation of protein kinase C, extracellular signal-regulated kinase 1/2, c-Jun N-terminal kinase, and p38 mitogen-activated protein kinases. Treatment with PMA increased activator protein-1 activity and the binding of c-Jun to the cyclic AMP response element of the COX-2 promoter, effects that were blocked by ursolic acid. These data are important for understanding the anticancer and anti-inflammatory properties of ursolic acid.

Blotting, Northern↗

PubMed2000

Benzo[a]pyrene induces the transcription of cyclooxygenase-2 in vascular smooth muscle cells. Evidence for the involvement of extracellular signal-regulated kinase and NF-kappaB.

Polycyclic aromatic hydrocarbons, such as benzo[a]pyrene (B[a]P) present in tobacco smoke and tar, have been implicated in the development of atherosclerosis as well as cancer. Increased expression of cyclooxygenase-2 (COX-2) has been detected both in atherosclerotic lesions and in epithelial cancers. To determine whether polycyclic aromatic hydrocarbons might directly affect COX expression in vascular cells, we investigated the effects of B[a]P on COX-2 expression in human and rat arterial smooth muscle cells (SMC). Treatment with B[a]P increased levels of COX-2 protein and mRNA and enhanced prostaglandin synthesis. Nuclear runoff assays and transient transfections revealed increased COX-2 gene transcription after treatment with B[a]P. Experiments were done to define the signaling mechanism by which B[a]P induced COX-2. B[a]P caused a rapid increase in phosphorylation of extracellular signal-regulated kinase (ERK); pharmacologic inhibition of mitogen-activated protein kinase kinase blocked B[a]P-mediated induction of COX-2. Depletion of the intracellular antioxidant, glutathione, with buthionine sulfoximine significantly increased B[a]P-mediated induction of COX-2 while exposure to N-acetylcysteine, a precursor of glutathione, suppressed the induction of COX-2 by B[a]P. Several lines of evidence suggest that the induction of COX-2 by B[a]P is mediated, at least in part, by NF-kappaB. Treatment with B[a]P increased binding of NF-kappaB to DNA. Moreover, B[a]P-mediated stimulation of COX-2 promoter activity was blocked when a construct containing a mutagenized NF-kappaB site was used. Pharmacological inhibitors of NF-kappaB blocked the induction of COX-2 protein and the stimulation of COX-2 promoter activity by B[a]P. Taken together, these data are likely to be important for understanding the atherogenic effects of tobacco smoke.

Animals↗

PubMed1999

Regulation of cyclooxygenase-2 by interferon gamma and transforming growth factor alpha in normal human epidermal keratinocytes and squamous carcinoma cells. Role of mitogen-activated protein kinases.

Treatment of normal human epidermal keratinocytes (NHEK) with interferon-gamma (IFN-gamma) causes a 9-fold increase in the level of cyclooxygenase-2 (COX-2) mRNA expression. Nuclear run-off assays indicate that this induction is at least partly due to increased transcription. Activation of the epidermal growth factor receptor (EGFR) signaling pathway due to the enhanced transforming growth factor alpha (TGFalpha) expression plays an important role in the induction of COX-2 by IFN-gamma. This is supported by the ability of TGFalpha to rapidly induce COX-2 and the inhibition of the IFN-gamma-mediated COX-2 mRNA induction by an EGFR antibody and EGFR-selective kinase inhibitors. Deletion and mutation analysis indicates the importance of the proximal cAMP-response element/ATF site in the transcriptional control of this gene by TGFalpha. The increase in COX-2 mRNA by TGFalpha requires activation of both the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) pathways. Inhibition of p38 MAPK decreases the stability of COX-2 mRNA, while inhibition of MAPK/ERK kinase (MEK) does not. These results suggest that the p38 MAPK signaling pathway controls COX-2 at the level of mRNA stability, while the ERK signaling pathway regulates COX-2 at the level of transcription. In contrast to NHEK, IFN-gamma and TGFalpha are not very effective in inducing TGFalpha or COX-2 expression in several squamous carcinoma cell lines, indicating alterations in both IFN-gamma and TGFalpha response pathways.

Amphiregulin↗

PubMed1999

Heartburn risk factors, knowledge, and prevention strategies: a population-based survey of individuals with heartburn.

BACKGROUND: Twenty-five million adults experience heartburn daily. To target individuals for prevention programs, characteristics of persons with heartburn and the associated causes of this condition must first be identified. METHODS: We conducted a population-based telephone survey of 2000 individuals with heartburn to describe the cause of the disease, knowledge of risk factors, and prevention strategies. RESULTS: Lifestyle and work habits, and certain food and beverage consumption, were associated with heartburn. Women reported the onset of heartburn about 5 years later than men. Survey respondents were unaware of the risk factors for heartburn, and sex-dependent differences in knowledge were apparent. Logistic regression modeling identified increasing age, female sex, higher level of education, and frequent vs infrequent heartburn as significant (P<.02) predictors of whether patients told a physician about their heartburn symptoms. Increasing age, higher body mass index, and reduced level of education were significant (P<.02) predictors of frequent vs infrequent heartburn in this study population. CONCLUSION: The findings of this study provide a framework for the development of a heartburn prevention program based on lifestyle modification.

Adult↗

PubMed1999

Inhibitory effects of caffeic acid phenethyl ester on the activity and expression of cyclooxygenase-2 in human oral epithelial cells and in a rat model of inflammation.

We investigated the mechanisms by which caffeic acid phenethyl ester (CAPE), a phenolic antioxidant, inhibited the stimulation of prostaglandin (PG) synthesis in cultured human oral epithelial cells and in an animal model of acute inflammation. Treatment of cells with CAPE (2.5 microg/ml) suppressed phorbol ester (12-O-tetradecanoylphorbol-13-acetate; TPA) and calcium ionophore (A23187)-mediated induction of PGE2 synthesis. This relatively low concentration of CAPE did not affect amounts of cyclooxygenase (COX) enzymes. CAPE nonselectively inhibited the activities of baculovirus-expressed hCOX-1 and hCOX-2 enzymes. TPA- and A23187-stimulated release of arachidonic acid from membrane phospholipids was also suppressed by CAPE (4-8 microg/ml). Higher concentrations of CAPE (10-20 microg/ml) suppressed the induction of COX-2 mRNA and protein mediated by TPA. Transient transfections using human COX-2 promoter deletion constructs were performed; the effects of TPA and CAPE were localized to a 124-bp region of the COX-2 promoter. In the rat carrageenan air pouch model of inflammation, CAPE (10-100 mg/kg) caused dose-dependent suppression of PG synthesis. Amounts of COX-2 in the pouch were markedly suppressed by 100 mg/kg CAPE but were unaffected by indomethacin. These data are important for understanding the anticancer and anti-inflammatory properties of CAPE.

Air↗

PubMed1999

Inhibition of cyclooxygenase-2 gene expression by p53.

Oncogenes enhance the expression of cyclooxygenase (Cox)-2, but interactions between tumor suppressor genes and Cox-2 have not been studied. In the present work, we have compared the levels of Cox-2 and the production of prostaglandin E2 in mouse embryo fibroblasts that do not express any p53 ((10)1) versus the same cell line ((10. 1)Val5) engineered to overexpress wild-type (wt) p53 at 32 degrees C or mutant p53 at 39 degrees C. Cells expressing wt p53 showed about a 10-fold decrease in synthesis of prostaglandin E2 compared with those expressing mutant p53. Levels of Cox-2 protein and mRNA were markedly suppressed by wt p53 but not by mutant p53. Nuclear run-offs revealed decreased rates of Cox-2 transcription in cells expressing wt p53. The activity of the Cox-2 promoter was reduced by 85% in cells expressing wt p53 but was reduced only by 30% in cells expressing mutant p53 compared with cells null for p53. The effect of p53 on the suppression of Cox-2 promoter activity was localized to the first 40 base pairs 5' from the transcription start site. Electrophoretic mobility shift assay revealed that p53 competed with TATA-binding protein for binding to mouse Cox-2 or human Cox-2 promoter extending from -50 to +52 base pairs. The results of this study suggest that interactions between p53 and Cox-2 could be important for understanding why levels of Cox-2 are undetectable in normal cells and increased in many tumors.

Animals↗

PubMed1999

Transcriptional activation of cyclooxygenase-2 in Wnt-1-transformed mouse mammary epithelial cells.

Wnt-1 acts as a mammary oncogene when ectopically expressed in the mouse mammary gland. APC is a tumor suppressor gene, mutations in which cause intestinal tumorigenesis in humans and rodents. Both Wnt-1 expression and APC mutation activate a common signaling pathway involving transcriptional activation mediated by beta-catenin/Tcf complexes, but few targets relevant to carcinogenesis have yet been identified. Expression of the inducible prostaglandin synthase cyclooxygenase-2 appears critical for intestinal tumorigenesis resulting from APC mutation, suggesting that cyclooxygenase-2 might be a transcriptional target for beta-catenin/Tcf complexes. Here, we have investigated the effect of Wnt-1 on cyclooxygenase-2 expression. Wnt-1 expression in the mouse mammary epithelial cell lines RAC311 and C57MG induces stabilization of cytosolic beta-catenin and morphological transformation. Expression of Wnt-1 in these cells caused transcriptional up-regulation of the cyclooxygenase-2 gene, resulting in increased levels of cyclooxygenase-2 mRNA and protein. Prostaglandin E2 production was increased as a consequence of the elevated cyclooxygenase-2 activity and could be decreased by treatment with a selective cyclooxygenase-2 inhibitor. Cyclooxygenase-2 thus appears to be a common downstream target for APC mutation and Wnt-1 expression. In view of the critical role of cyclooxygenase-2 in intestinal tumorigenesis, cyclooxygenase-2 up-regulation in response to Wnt signaling may contribute to Wnt-induced mammary carcinogenesis.

Animals↗

PubMed1999

Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer.

A large body of evidence suggests that cyclooxygenase-2 (COX-2) is important in gastrointestinal cancer. The purpose of this study was to determine whether COX-2 was expressed in adenocarcinoma of the human pancreas. Quantitative reverse transcription-PCR, immunoblotting, and immunohistochemistry were used to assess the expression of COX-2 in pancreatic tissue. Levels of COX-2 mRNA were increased by >60-fold in pancreatic cancer compared to adjacent nontumorous tissue. COX-2 protein was present in 9 of 10 cases of adenocarcinoma of the pancreas but was undetectable in nontumorous pancreatic tissue. Immunohistochemical analysis showed that COX-2 was expressed in malignant epithelial cells. In cultured human pancreatic cancer cells, levels of COX-2 mRNA and protein were induced by treatment with tumor-promoting phorbol esters. Taken together, these results suggest that COX-2 may be a target for the prevention or treatment of pancreatic cancer.

Adenocarcinoma↗

PubMed1999

Cyclooxygenase-2 expression is up-regulated in squamous cell carcinoma of the head and neck.

The purpose of this study was to determine whether cyclooxygenase-2 (COX-2) was overexpressed in squamous cell carcinoma of the head and neck (HNSCC). Quantitative reverse transcription-PCR, immunoblotting, and immunohistochemistry were used to assess the expression of COX-2 in head and neck tissue. Mean levels of COX-2 mRNA were increased by nearly 150-fold in HNSCC (n = 24) compared with normal oral mucosa from healthy volunteers (n = 17). Additionally, there was about a 50-fold increase in amounts of COX-2 mRNA in normal-appearing epithelium adjacent to HNSCC (n = 10) compared with normal oral mucosa from healthy volunteers. Immunoblotting demonstrated that COX-2 protein was present in six of six cases of HNSCC but was undetectable in normal oral mucosa from healthy subjects. Immunohistochemical analysis showed that COX-2 was expressed in both HNSCC and adjacent normal-appearing epithelium. Taken together, these results suggest that COX-2 may be a target for the prevention or treatment of HNSCC.

Carcinoma, Squamous Cell↗

PubMed1999

A novel synthetic oleanane triterpenoid, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid, with potent differentiating, antiproliferative, and anti-inflammatory activity.

The new synthetic oleanane triterpenoid 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO) is a potent, multifunctional molecule. It induces monocytic differentiation of human myeloid leukemia cells and adipogenic differentiation of mouse 3T3-L1 fibroblasts and enhances the neuronal differentiation of rat PC12 pheochromocytoma cells caused by nerve growth factor. CDDO inhibits proliferation of many human tumor cell lines, including those derived from estrogen receptor-positive and -negative breast carcinomas, myeloid leukemias, and several carcinomas bearing a Smad4 mutation. Furthermore, it suppresses the abilities of various inflammatory cytokines, such as IFN-gamma, interleukin-1, and tumor necrosis factor-alpha, to induce de novo formation of the enzymes inducible nitric oxide synthase (iNos) and inducible cyclooxygenase (COX-2) in mouse peritoneal macrophages, rat brain microglia, and human colon fibroblasts. CDDO will also protect rat brain hippocampal neurons from cell death induced by beta-amyloid. The above activities have been found at concentrations ranging from 10(-6) to 10(-9) M in cell culture, and these results suggest that CDDO needs further study in vivo, for either chemoprevention or chemotherapy of malignancy as well as for neuroprotection.

3T3 Cells↗

PubMed1999

Administration of an unconjugated bile acid increases duodenal tumors in a murine model of familial adenomatous polyposis.

Intestinal carcinogenesis involves the successive accumulation of multiple genetic defects until cellular transformation to an invasive phenotype occurs. This process is modulated by many epigenetic factors. Unconjugated bile acids are tumor promoters whose presence in intestinal tissues is regulated by dietary factors. We studied the role of the unconjugated bile acid, chenodeoxycholate, in an animal model of familial adenomatous polyposis. Mice susceptible to intestinal tumors as a result of a germline mutation in Apc (Min/+ mice) were given a 10 week dietary treatment with 0.5% chenodeoxycholate. Following this, the mice were examined to determine tumor number, enterocyte proliferation, apoptosis and beta-catenin expression. Intestinal tissue prostaglandin E2 (PGE2) levels were also assessed. Administration of chenodeoxycholate in the diet increased duodenal tumor number in Min/+ mice. Promotion of duodenal tumor formation was accompanied by increased beta-catenin expression in duodenal cells, as well as increased PGE2 in duodenal tissue. These data suggest that unconjugated bile acids contribute to periampullary tumor formation in the setting of an Apc mutation.

Adenomatous Polyposis Coli↗

PubMed1999

Curcumin inhibits cyclooxygenase-2 transcription in bile acid- and phorbol ester-treated human gastrointestinal epithelial cells.

We investigated whether curcumin, a chemopreventive agent, inhibited chenodeoxycholate (CD)- or phorbol ester (PMA)-mediated induction of cyclooxygenase-2 (COX-2) in several gastrointestinal cell lines (SK-GT-4, SCC450, IEC-18 and HCA-7). Treatment with curcumin suppressed CD- and PMA-mediated induction of COX-2 protein and synthesis of prostaglandin E2. Curcumin also suppressed the induction of COX-2 mRNA by CD and PMA. Nuclear run-offs revealed increased rates of COX-2 transcription after treatment with CD or PMA and these effects were inhibited by curcumin. Treatment with CD or PMA increased binding of AP-1 to DNA. This effect was also blocked by curcumin. In addition to the above effects on gene expression, we found that curcumin directly inhibited the activity of COX-2. These data provide new insights into the anticancer properties of curcumin.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1999

Inhibition of cyclooxygenase-2 expression. An approach to preventing head and neck cancer.

Cyclooxygenase (COX) catalyzes the formation of prostaglandins (PG) from arachidonic acid. A large body of evidence has accumulated to suggest that COX-2, the inducible form of COX, is important in carcinogenesis. In this study, we determined whether (1) COX-2 was overexpressed in squamous cell carcinoma of the head and neck (HNSCC) and whether (2) retinoids, a class of chemopreventive agents, blocked epidermal growth factor (EGF)-mediated activation of COX-2 expression. Levels of COX-2 mRNA were determined in 15 cases of HNSCC and 10 cases of normal oral mucosa. Nearly a 100-fold increase in amounts of COX-2 mRNA was detected in HNSCC. By immunoblot analysis, COX-2 protein was detected in 6 of 6 cases of HNSCC but was undetectable in normal mucosa. Because retinoids protect against oral cavity cancer, we investigated whether retinoids could suppress EGF-mediated induction of COX-2 in cultured oral squamous carcinoma cells. Treatment with EGF led to increased levels of COX-2 mRNA, COX-2 protein, and synthesis of PG. These effects were suppressed by a variety of retinoids. Based on the results of this study, it will be important to establish whether newly developed selective COX-2 inhibitors are useful in preventing or treating HNSCC. Moreover, the anticancer properties of retinoids may be due, in part, to inhibition of COX-2 expression. Combining a retinoid with a selective COX-2 inhibitor may be more effective than either agent alone in preventing cancer of the upper aerodigestive tract.

Carcinoma, Squamous Cell↗

PubMed1999

Resveratrol inhibits cyclooxygenase-2 transcription in human mammary epithelial cells.

A large body of evidence suggests that inhibiting cyclooxygenase-2 (COX-2), the inducible form of COX, will be an important strategy for preventing cancer. In this study, we investigated whether resveratrol, a chemopreventive agent found in grapes, could suppress phorbol ester (PMA)-mediated induction of COX-2 in human mammary and oral epithelial cells. Treatment of cells with PMA induced COX-2 mRNA, COX-2 protein, and prostaglandin synthesis. These effects were inhibited by resveratrol. Nuclear runoffs revealed increased rates of COX-2 transcription after treatment with PMA, an effect that was inhibited by resveratrol. Resveratrol inhibited PMA-mediated activation of protein kinase C and the induction of COX-2 promoter activity by c-Jun. Phorbol ester-mediated induction of AP-1 activity was blocked by resveratrol. These data are likely to be important for understanding the anticancer and anti-inflammatory properties of resveratrol.

Antineoplastic Agents, Phytogenic↗