Up-regulation of cyclooxygenase-2 expression and prostaglandin synthesis in endometrial stromal cells by malignant endometrial epithelial cells. A paracrine effect mediated by prostaglandin E2 and nuclear factor-kappa B

Endometrial causes of recurrent pregnancy losses: endometriosis, adenomyosis, and chronic endometritis

Chronic inflammatory processes affecting the endometrium, as encountered in endometriosis, adenomyosis, and chronic endometritis, alter endometrial receptivity. These disorders are associated with early pregnancy losses and possibly recurrent pregnancy losses (RPL). In the cases of endometriosis, other factors associated with the disease also are susceptible of causing miscarriages and possibly RPL, such as an impact of intrapelvic inflammatory processes affecting the oocyte and embryo in case of natural conception. Conversely these latter effects obviously are bypassed in case of assisted reproductive technology. Chronic inflammation of the endometrium in the condition known as chronic endometritis also causes early pregnancy losses and RPL with beneficial effects achieved when specific treatment is undertaken.

The Role of Eicosanoids in Gynecological Malignancies

Eicosanoids, bio-active lipid molecules, evoke a multitude of biological effects that directly affect cancer cells and indirectly affect tumor microenvironment. An emerging role has been shown for eicosanoids in the pathogenesis of gynecological malignancies which include cancers of the vulva, vagina, cervix, uterine, and ovary. Eicosanoid biosynthesis pathways start at the metabolism of phospholipids by phospholipase A2 then proceeding to one of three pathways: the cyclooxygenase (COX), lipoxygenase (LOX), or P450 epoxygenase pathways. The most studied eicosanoid pathways include COX and LOX; however, more evidence is appearing to support further study of the P450 epoxygenase pathway in gynecologic cancers. In this review, we present the current knowledge of the role of COX, LOX and P450 pathways in the pathogenesis of gynecologic malignancies. Vulvar and vaginal cancer, the rarest subtypes, there is association of COX-2 expression with poor disease specific survival in vulvar cancer and, in vaginal cancer, COX-2 expression has been found to play a role in mucosal inflammation leading to disease susceptibility and transmission. Cervical cancer is associated with COX-2 levels 7.4 times higher than in healthy tissues. Additionally, HPV elevates COX-2 levels through the EGFR pathway and HIV promotes elevated COX-2 levels in cervical tissue as well as increases PGE2 levels eliciting inflammation and progression of cancer. Evidence supports significant roles for both the LOX and COX pathways in uterine cancer. In endometrial cancer, there is increased expression of 5-LOX which is associated with adverse outcomes. Prostanoids in the COX pathway PGE2 and PGF2α have been shown to play a significant role in uterine cancer including alteration of proliferation, adhesion, migration, invasion, angiogenesis, and the inflammatory microenvironment. The most studied gynecological malignancy in regard to the potential role of eicosanoids in tumorigenesis is ovarian cancer in which all three pathways have shown to be associated or play a role in ovarian tumorigenesis directly on the tumor cell or through modulation of the tumor microenvironment. By identifying the gaps in knowledge, additional pathways and targets could be identified in order to obtain a better understanding of eicosanoid signaling in gynecological malignancies and identify potential new therapeutic approaches.

Endometriosis

Pelvic endometriosis is a complex syndrome characterized by an estrogen-dependent chronic inflammatory process that affects primarily pelvic tissues, including the ovaries. It is caused when shed endometrial tissue travels retrograde into the lower abdominal cavity. Endometriosis is the most common cause of chronic pelvic pain in women and is associated with infertility. The underlying pathologic mechanisms in the intracavitary endometrium and extrauterine endometriotic tissue involve defectively programmed endometrial mesenchymal progenitor/stem cells. Although endometriotic stromal cells, which compose the bulk of endometriotic lesions, do not carry somatic mutations, they demonstrate specific epigenetic abnormalities that alter expression of key transcription factors. For example, GATA-binding factor-6 overexpression transforms an endometrial stromal cell to an endometriotic phenotype, and steroidogenic factor-1 overexpression causes excessive production of estrogen, which drives inflammation via pathologically high levels of estrogen receptor-β. Progesterone receptor deficiency causes progesterone resistance. Populations of endometrial and endometriotic epithelial cells also harbor multiple cancer driver mutations, such as KRAS, which may be associated with the establishment of pelvic endometriosis or ovarian cancer. It is not known how interactions between epigenomically defective stromal cells and the mutated genes in epithelial cells contribute to the pathogenesis of endometriosis. Endometriosis-associated pelvic pain is managed by suppression of ovulatory menses and estrogen production, cyclooxygenase inhibitors, and surgical removal of pelvic lesions, and in vitro fertilization is frequently used to overcome infertility. Although novel targeted treatments are becoming available, as endometriosis pathophysiology is better understood, preventive approaches such as long-term ovulation suppression may play a critical role in the future.

Regulation of Inflammation Pathways and Inflammasome by Sex Steroid Hormones in Endometriosis

Endometriosis is a gynecological disorder characterized by the growth of endometrial tissue (glands and stroma) outside the uterus, mainly in the peritoneal cavity, ovaries, and intestines. This condition shows estrogen dependency and progesterone resistance, and it has been associated with chronic inflammation, severe pain, and infertility, which negatively affect the quality of life in reproductive women. The molecular mechanisms involved in the pathogenesis of endometriosis are not completely understood; however, inflammation plays a key role in the pathophysiology of the disease, mainly by altering the function of immune cells (macrophages, natural killer, and T cells) and increasing levels of pro-inflammatory mediators in the peritoneal cavity, endometrium, and blood. These immune alterations inhibit apoptotic pathways and promote adhesion and proliferation of endometriotic cells, as well as angiogenesis and neurogenesis in endometriotic lesions. It has been demonstrated that hormonal alterations in endometriosis are related to the inflammatory unbalance in this disease. Particularly, steroid hormones (mainly estradiol) promote the expression and release of pro-inflammatory factors. Excessive inflammation in endometriosis contributes to changes of hormonal regulation by modulating sex steroid receptors expression and increasing aromatase activity. In addition, dysregulation of the inflammasome pathway, mediated by an alteration of cellular responses to steroid hormones, participates in disease progression through preventing cell death, promoting adhesion, invasion, and cell proliferation. Furthermore, inflammation is involved in endometriosis-associated infertility, which alters endometrium receptivity by impairing biochemical responses and decidualization. The purpose of this review is to present current research about the role of inflammasome in the pathogenesis of endometriosis as well as the molecular role of sex hormones in the inflammatory responses in endometriosis.

6-Shogaol reduces progression of experimental endometriosis in vivo and in vitro via regulation of VGEF and inhibition of COX-2 and PGE2-mediated inflammatory responses

Endometriosis (EM) is one of the most common gynaecological disorder affecting women in their reproductive age. Mechanisms involved in the pathogenesis of EM remains poorly understood, however inflammatory responses have been reported to be significantly involved. The efficacy of 6-shogaol on proliferation of endometriotic lesions and inflammatory pathways in experimentally-induced EM model was explored in this study. EM was stimulated in Sprague-Dawley rats by implantation of autologous endometrium onto the peritoneum abdominal wall. Separate groups were treated with 6-shogaol (50, 100 or 150 mg/kg b.wt/day) via oral gavage for one month period. Gestrinone (GTN) group received GTN (0.5 mg/kg/day) as positive control. Five weeks after implantation, the spherical volume of ecto-uterine tissues was determined. Treatment with 6-shogaol significantly reduced the implant size. Histological analysis reported atrophy and regression of the lesions. 6-shogaol administration effectively down-regulated NF-κB signaling, VEGF and VEGFR-2 (Flk-1) expression in the endometriotic lesions. Excess production of IL-1β and IL-6 (pro-inflammatory cytokines), PGE2 and nitric oxide (NO) were reduced. Overall, the results of the study reveal the efficacy of 6-shogaol against endometriosis via effectively suppressing proliferation of the lesions and modulating angiogenesis and COX-2/NF-κB-mediated inflammatory cascades.

Aspirin use and endometrial cancer risk and survival

The role of acetylsalicylic acid (aspirin) as a chemo-preventive and adjuvant therapeutic agent for cancers is generating attention. Mounting evidence indicates that aspirin reduces the incidence and mortality of certain obesity-related cancers, particularly colorectal cancer. In endometrial cancer, previous studies examining the effect of aspirin remain inconsistent as to the reduction in the risk of endometrial cancer. While some evidence indicates protective effects in obese women, other studies have showed a potential deleterious effect of these medications on endometrial cancer outcomes. However, exposure measurement across studies has been inconsistent in recording dose, duration, and frequency of use; thus making comparisons difficult. In this article, we review the evidence for the association between endometrial cancer and obesity, the pharmacological differences between regular- and low-dose aspirin, as well as the potential anti-tumor mechanism of aspirin, supporting a possible therapeutic effect on endometrial cancer. A proposed mechanism behind decreased cancer mortality in endometrial cancer may be a result of inhibition of metastasis via platelet inactivation and possible prostaglandin E₂ suppression by aspirin. Additionally, aspirin use in particular may have a secondary benefit for obesity-related comorbidities including cardiovascular disease in women with endometrial cancer. Although aspirin-related bleeding needs to be considered as a possible adverse effect, the benefits of aspirin therapy may exceed the potential risk in women with endometrial cancer. The current evidence reviewed herein has resulted in conflicting findings regarding the potential effect on endometrial cancer outcomes, thus indicating that future studies in this area are needed to resolve the effects of aspirin on endometrial cancer survival, particularly to identify specific populations that might benefit from aspirin use.

Local and systemic factors and implantation: what is the evidence?

Significant progress has been made in the understanding of embryonic competence and endometrial receptivity since the inception of assisted reproductive technology. The endometrium is a highly dynamic tissue that plays a crucial role in the establishment and maintenance of normal pregnancy. In response to steroid sex hormones, the endometrium undergoes marked changes during the menstrual cycle that are critical for acceptance of the nascent embryo. There is also a wide body of literature on systemic factors that impact assisted reproductive technology outcomes. Patient prognosis is impacted by an array of factors that tip the scales in her favor or against success. Recognizing the local and systemic factors will allow clinicians to better understand and optimize the maternal environment at the time of implantation. This review will address the current literature on endometrial and systemic factors related to impaired implantation and highlight recent advances in this area of reproductive medicine.

MAP kinases and the inflammatory signaling cascade as targets for the treatment of endometriosis?

INTRODUCTION

The pathogenesis of endometriosis, a common benign disease, remains ill-defined, although it is clear that chronic inflammation plays a crucial role through mitogen-activated protein kinase (MAPK) signaling pathways. All current medical therapies for endometriosis are antigonadotropic, and therefore have a contraceptive effect. A concerted research effort is hence warranted with the aim of delivering novel therapeutics that reduces disease symptoms without blocking ovulation.

AREAS COVERED

The authors review the complex pathogenic mechanisms of chronic inflammation in endometriosis and their relationships with MAPK pathways. The authors conducted a literature search of descriptive and functional targeted validation of MAPK in the pathogenesis of endometriosis. The effects of MAPK inhibitors, which constitute potential agents for future treatments, are also described.

EXPERT OPINION

Preliminary studies have highlighted a crucial role for MAPK in driving endometriosis-related inflammation. MAPK inhibitors exhibit potent activity in terms of controlling growth of endometriosis lesions both in vitro and in animal models. As MAPK inhibitors are known to have a multitude of undesirable side effects, their use in humans has to be approached with great care. Indeed, use of these drugs would probably be limited to short exposures prior to surgery in cases involving the most severe disease phenotypes.

Lipoxin A₄ prevents the progression of de novo and established endometriosis in a mouse model by attenuating prostaglandin E₂ production and estrogen signaling

Endometriosis, a leading cause of pelvic pain and infertility, is characterized by ectopic growth of endometrial-like tissue and affects approximately 176 million women worldwide. The pathophysiology involves inflammatory and angiogenic mediators as well as estrogen-mediated signaling and novel, improved therapeutics targeting these pathways are necessary. The aim of this study was to investigate mechanisms leading to the establishment and progression of endometriosis as well as the effect of local treatment with Lipoxin A₄ (LXA₄), an anti-inflammatory and pro-resolving lipid mediator that we have recently characterized as an estrogen receptor agonist. LXA₄ treatment significantly reduced endometriotic lesion size and downregulated the pro-inflammatory cytokines IL-1β and IL-6, as well as the angiogenic factor VEGF. LXA₄ also inhibited COX-2 expression in both endometriotic lesions and peritoneal fluid cells, resulting in attenuated peritoneal fluid Prostaglandin E₂ (PGE₂) levels_. Besides its anti-inflammatory effects, LXA₄ differentially regulated the expression and activity of the matrix remodeling enzyme matrix metalloproteinase (MMP)-9 as well as modulating transforming growth factor (TGF)-β isoform expression within endometriotic lesions and in peritoneal fluid cells. We also report for first time that LXA₄ attenuated aromatase expression, estrogen signaling and estrogen-regulated genes implicated in cellular proliferation in a mouse model of disease. These effects were observed both when LXA₄ was administered prior to disease induction and during established disease. Collectively, our findings highlight potential targets for the treatment of endometriosis and suggest a pleotropic effect of LXA₄ on disease progression, by attenuating pro-inflammatory and angiogenic mediators, matrix remodeling enzymes, estrogen metabolism and signaling, as well as downstream proliferative pathways.

Cyclooxygenase-2 Expression in Uterine Leiomyosarcomas

Many studies have focused on cyclooxygenase-2 (COX-2) alterations as a critical step in the onset and progression of cancer. Moreover, a strong correlation between COX-2 and chemoresistance has been demonstrated in several carcinomas. Recently, COX-2 expression has been observed in uterine carcinosarcoma, osteosarcoma, and rhabdomyosarcoma. We investigated COX-2 expression in chemoresistant uterine leiomyosarcoma in 30 patients who had undergone surgical treatment. COX-2 expression was observed in 13 cases (43.3%). Of the 13 patients with distinct COX-2 positive immunoreactivity uterine leiomyosarcomas, 7 had stage I or II disease and 6 had stage III or IV disease. The expression of COX-2 in uterine stromal malignancies may reveal a therapeutic hypothesis in the context of uterine leiomyosarcoma molecular chemotherapeutic approach.

Modulation of signaling pathways in prostate cancer by green tea polyphenols

Prostate cancer (PCa) is the most common malignancy found in American men and the risk factors for PCa include age, family history, ethnicity, hormonal status, diet and lifestyle. For the successful development of cancer-preventive/therapeutic approaches, consumption of dietary agents capable of inhibiting or delaying the growth and proliferation of cancer cells without significantly affecting normal cells could be an effective strategy. Polyphenols derived from green tea, termed as green tea polyphenols (GTP) have received great attention in recent years for their beneficial effects, in particular, their significant involvement in cancer chemoprevention and chemotherapy. Several studies have reported beneficial effects of GTP using in vitro and in vivo approaches and in human clinical trials. Among green tea catechins, epigallocatechin-3-gallate (EGCG) is best studied for its cancer preventive properties. In this review article, we present available scientific literature about the effects of GTP and EGCG on signaling pathways in PCa.

Nuclear factor-kappaB: a main regulator of inflammation and cell survival in endometriosis pathophysiology

OBJECTIVE

To update, analyze, and summarize the literature concerning nuclear factor-kappaB (NF-κB) participation in endometriosis pathophysiology.

DESIGN

Review.

RESULT(S)

Nuclear factor-kappaB is physiologically activated in the human endometrium, showing variable activity. A cyclic p65-DNA binding pattern was shown in the endometrium of healthy women. This cyclic pattern was altered in the endometrium of patients with endometriosis. Nuclear factor-kappaB is basally activated in peritoneal endometriotic lesions, showing higher p65 activity in red endometriotic lesions than in black lesions. In vivo and in vitro studies show up-regulation of inflammation and cell proliferation and down-regulation of apoptosis by NF-κB activity. Iron overload has been shown in the pelvic cavity of endometriosis patients, and iron overload and oxidative stress activate NF-κB in macrophages, which have been shown to participate in the endometriosis-associated inflammatory reaction.

CONCLUSION(S)

Nuclear factor-kappaB activation dysregulation in the endometrium of endometriosis patients may explain some endometrial biological alterations associated with endometriosis. The scientific evidence strongly suggests that NF-κB activity in endometriotic cells stimulates inflammation and cell proliferation and inhibits apoptosis, favoring the development and maintenance of endometriosis. Iron overload in the pelvic cavity of endometriosis patients could be a main factor enhancing oxidative stress and activating NF-κB in a chronic manner, contributing to endometriosis establishment and growth.

Pre-treatment diagnosis of endometrial cancer through a combination of CA125 and multiplication of neutrophil and monocyte

AIM

 This study aimed to investigate the clinical value of pre-treatment leukocyte differential counts and the prediction of endometrial cancer using leukocyte markers.

MATERIAL AND METHODS

Medical records of 238 women with pathologically confirmed endometrial cancer between March 2000 and June 2009 at two Korean hospitals were reviewed and compared to 596 healthy people visiting the Health Promotion Center in Gangnam Severance Hospital. For all study subjects, leukocyte differential counts and CA125 levels in serum obtained prior to operation were recorded. Multiplication of neutrophil and monocyte (MNM) was determined by multiplying neutrophil and monocyte counts then dividing by 10000. Differences between endometrial cancer patients and healthy controls were compared. The sensitivity and specificity for each marker as well as the combined use of CA125 and other leukocyte markers were assessed using receiver operating characteristic curves.

RESULTS

Mean white blood cell (WBC) counts were 6676 (6440-6913) cells/µL in endometrial cancer patients compared to 5663 (5542-5784) cells/µL in healthy controls (P<0.001). The area under curve (AUC) for CA125 was 0.689 with a sensitivity of 49.13% and specificity of 83.1% using an optimal cut-off value of 18.7U/mL. The AUC for MNM was 0.696 with a sensitivity of 62.9% and specificity of 69.1%. The combination of CA125 and MNM showed a higher AUC of 0.760 than use of CA125 or MNM alone.

CONCLUSION

The combination of MNM and CA125 is a simple and cost-effective method for predicting endometrial cancer.

The relationship of COX-2 expression with estrogen receptor, progesterone receptor and prognostic parameters in endometrial carcinomas

AIM

Endometrial cancer (EC), which is the most common gynecologic cancer, develops as a result of disruption of the delicate balance between cell proliferation and cell loss, or apoptosis through activation of oncogenesis, or loss of tumor suppressor genes. Among the biochemical factors proposed to give a more detailed characterization of EC biology, estrogen receptors (ER) and progesterone receptors (PR) play a major role. Most of the studies in the literature have shown increased expression of cyclooxygenase-2 (COX-2) in EC. Recent experiments suggest that COX-2 antagonizes cell apoptosis, increases the invasiveness of malignant cells and promotes angiogenesis. The aim of this study was to investigate the expression of COX-2 in EC, to study its correlation to established menstrual status, grade, myometrial invasion, lymph node status, stage and ER and PR status.

MATERIAL & METHODS

The study was performed on 72 ECs. Immunohistochemically was analyzed for ER, PR, and COX-2.

RESULTS

COX-2 positivity was found in 91.7% of the cases. In 61 cases (84.7%) there was ER positive staining, and in 59 cases (81.9%) PR positive staining was observed. We have not found a statistically significant relation between COX-2 and prognostic factors, ER and PR.

CONCLUSIONS

A high expression rate still suggests a probable relation with endometrial carcinogenesis. If such a relation exists, new therapeutic options might be available in the future.

Prostaglandin E2: the master of endometriosis?

Endometriosis is the primary cause of infertility in women, with a prevalence rate ranging from 5% to 10%. Women with endometriosis suffer from symptoms such as chronic pelvic pain, dysmenorrhea and dyspareunia, which significantly reduce the quality of life. Endometriosis is a polygenic disease with a complex, multifactorial etiology. The mechanism responsible for the initiation and development of this disease remains largely unknown. Prostaglandin E2 (PGE2), a versatile eicosanoid that exerts numerous physiological and pathological functions, has been implicated to play critical roles in the development of endometriosis. A growing body of evidence demonstrates that PGE2 regulates many pathophysiological processes including cell proliferation, antiapoptosis, immune suppression and angiogenesis during the development of endometriosis. This review focuses on recent advances in cellular and molecular mechanisms triggered by PGE2 that contribute to the pathological processes of endometriosis.

Involvement of the nuclear factor-κB pathway in the pathogenesis of endometriosis

OBJECTIVE

To evaluate the role of nuclear factor-κB (NF-κB) in the pathogenesis of endometriosis.

DESIGN

A literature search was conducted in PubMed to identify all relevant citations.

RESULT(S)

Our findings highlight the important role of NF-κB in the pathophysiology of endometriosis. In vitro and in vivo studies show that NF-κB-mediated gene transcription promotes inflammation, invasion, angiogenesis, and cell proliferation and inhibits apoptosis of endometriotic cells. Constitutive activation of NF-κB has been demonstrated in endometriotic lesions and peritoneal macrophages of endometriosis patients. Agents blocking NF-κB are effective inhibitors of endometriosis development and some drugs with known NF-κB inhibitory properties have proved efficient at reducing endometriosis-associated symptoms in women. Iron overload activates NF-κB in macrophages. NF-κB activation in macrophages and ectopic endometrial cells stimulates synthesis of proinflammatory cytokines, generating a positive feedback loop in the NF-κB pathway and promoting endometriotic lesion establishment, maintenance and development.

CONCLUSION(S)

NF-κB transcriptional activity modulates key cell processes contributing to the initiation and progression of endometriosis. Because endometriosis is a multifactorial disease, inhibiting NF-κB appears to be a promising strategy for future therapies targeting different cell functions involved in endometriosis development, such as cell adhesion, invasion, angiogenesis, inflammation, proliferation, and apoptosis. Upcoming research will elucidate these hypotheses.

Role of progesterone in endometrial cancer

Progesterone is a key hormone in the endometrium that opposes estrogen-driven growth. Insufficient progesterone will result in unopposed estrogen action that could lead to the development of endometrial hyperplasia and adenocarcinoma. Although these endometrial neoplasias can regress in response to progestin treatment, this does not occur in all instances. To understand this resistance to progesterone and to improve on existing hormonal therapies, it is imperative that the molecular mechanisms of progesterone action through its receptor be deciphered in endometrial cancer. This review highlights what is known thus far regarding the efficacy of progestin therapy in the clinic and the role of progesterone in endometrial cancer cell behavior and gene regulation.

Estrogen metabolism and action in endometriosis

Endometriosis is a complex estrogen-dependent disease that is defined as the presence of endometrial glands and stroma outside the uterine cavity. The etiology of endometriosis is multifactorial and includes complex interactions of genetic, immunological, hormonal and environmental factors. Many theories have been proposed, but no single theory can explain all aspects of endometriosis, suggesting that endometriosis is a heterogeneous disease. This review presents the current theories on the pathogenesis of endometriosis, followed by an overview on estrogen metabolism in normal endometrium and diseased endometrium of endometriosis patients. The potential role of aberrant expression of individual estrogen-metabolizing enzymes is discussed, and a model mechanism for increased formation of estradiol is presented separately for different types of endometriosis. The disturbed expression of estrogen receptors in endometriosis is detailed, and the estrogen biosynthetic enzymes and receptors are discussed as novel therapeutic targets for the treatment of endometriosis.

Estrogen receptor-beta mediates cyclooxygenase-2 expression and vascular prostanoid levels in human placental villous endothelial cells

OBJECTIVE

Regulation of fetoplacental blood flow is likely mediated by factors such as prostanoids. Estrogen and its receptors affect prostanoid biosynthesis. Previously, we demonstrated that villous endothelial cells express estrogen receptor-beta (ESR2), and we sought to determine its role in the mediation of fetoplacental vascular function.

STUDY DESIGN

Villous endothelial cells from uncomplicated pregnancies were isolated, cultured, and treated with estrogen. RNA interference, real-time polymerase chain reaction, Western blotting, and enzyme immunoassays were performed.

RESULTS

Cyclooxygenase-2 (COX-2) expression levels were not altered consistently by estrogen. RNA interference of ESR2 led to a concomitant decrease in COX-2 messenger RNA (P < .0001) and protein (P < .05) in the presence and absence of estradiol. ESR2 knock-down also led to diminished prostacyclin and thromboxane concentrations in the absence of estradiol (P < .005).

CONCLUSION

ESR2 mediates COX-2 expression levels and both prostacyclin and thromboxane concentrations in the basal state, which suggests the possibility of ligand-independent regulation of COX-2 activity and prostaglandin H2 substrate availability. Further investigation regarding ESR2 regulation of prostanoid biosynthesis and its effects on the fetoplacental vasculature is warranted.

Steroidogenic factor-1 and endometriosis

Endometriosis is a common and chronic disease characterized by persistent pelvic pain and infertility. Estradiol is essential for growth and inflammation in endometriotic tissue. The complete cascade of steroidogenic proteins/enzymes including aromatase is present in endometriosis leading to de novo estradiol synthesis. PGE(2) induces the expression of the genes that encode these enzymes. Upon PGE(2) treatment, coordinate recruitment of the nuclear receptor SF-1 to the promoters of these steroidogenic genes is the key event for estradiol synthesis. SF-1 is the key factor determining that an endometriotic cell will respond to PGE(2) by increased estradiol formation. The presence of SF-1 in endometriosis and its absence in endometrium is determined primarily by the methylation of its promoter. The key steroidogenic enzyme in endometriosis is aromatase encoded by a single gene because its inhibition blocks all estradiol biosynthesis. Aromatase inhibitors diminish endometriotic implants and associated pain refractory to existing treatments in affected women.

From endometrial hyperplasia to endometrial cancer: insight into the biology and possible medical preventive measures

Controversies are still seen in the histological differential diagnosis of hyperplasia and well-differentiated endometrial carcinoma. Prediction of endometrial cancer in patients with hyperplasia with atypia, with the available markers has not been reliable yet. Hence these patients require more attention in the clinical management. Endometrial hyperplasia is proliferation of endometrial glands resulting in a higher gland : stroma ratio. Cytological atypia, which may progress to or co-exist with endometrial cancer and other pathological changes, result from estrogen stimulation unopposed by progesterone. Biomarkers whose expression is altered in cases of endometrial hyperplasia or cancer such as progesterone receptor, insulin-like growth factor I, retinaldehyde dehydrogenase type II, and secreted frizzled-related protein 4, seem to be promising to use as early-stage tumor markers. Mutation of PTEN is present in 83% of endometrial adenocarcinoma cases, making it the most frequent early molecular genetic alteration in type 1 endometrial tumors, which are generally associated with hyperplasia. p53 gene mutation is not found in endometrial hyperplasia, but researchers have detected this mutation in 20% of cases of endometrial carcinoma and 90% of cases of serous endometrial tumors. Cyclooxygenase-2 is important in tumorogenic transformation of hyperplasia. Expression of cyclooxygenase-2 decreases apoptosis, increases angiogenesis, and is related to invasiveness. Cyclooxygenase-2 expression increases significantly in cases of well-differentiated endometrial adenocarcinoma. Prostaglandin E2 is known to regulate aromatase gene expression and is the product of cyclooxygenase-2. The data about aromatase inhibitors are promising; in breast cancer patients, treatment with tamoxifen induces uterine abnormalities as early as 3 months after the initiation of therapy. In contrast, these abnormalities are not seen in patients who receive aromatase inhibitors and switched therapy after tamoxifen withdrawal may reverse tamoxifen-associated endometrial thickening.

Targeting receptor tyrosine kinases for chemoprevention by green tea catechin, EGCG

Tea is one of the most popular beverages consumed worldwide. Epidemiologic studies show an inverse relationship between consumption of tea, especially green tea, and development of cancers. Numerous in vivo and in vitro studies indicate strong chemopreventive effects for green tea and its constituents against cancers of various organs. (–)-Epigallocatechin-3-gallate (EGCG), the major catechin in green tea, appears to be the most biologically active constituent in tea with respect to inhibiting cell proliferation and inducing apoptosis in cancer cells. Recent studies indicate that the receptor tyrosine kinases (RTKs) are one of the critical targets of EGCG to inhibit cancer cell growth. EGCG inhibits the activation of EGFR (erbB1), HER2 (neu/erbB2) and also HER3 (neu/erbB3), which belong to subclass I of the RTK superfamily, in various types of human cancer cells. The activation of IGF-1 and VEGF receptors, the other members of RTK family, is also inhibited by EGCG. In addition, EGCG alters membrane lipid organization and thus inhibits the dimerization and activation of EGFR. Therefore, EGCG inhibits the Ras/MAPK and PI3K/Akt signaling pathways, which are RTK-related cell signaling pathways, as well as the activation of AP-1 and NF-κB, thereby modulating the expression of target genes which are associated with induction of apoptosis and cell cycle arrest in cancer cells. These findings are significant because abnormalities in the expression and function of RTKs and their downstream effectors play a critical role in the development of several types of human malignancies. In this paper we review evidence indicating that EGCG exerts anticancer effects, at least in part, through inhibition of activation of the specific RTKs and conclude that targeting RTKs and related signaling pathway by tea catechins might be a promising strategy for the prevention of human cancers.

Aspirin, NSAID, and acetaminophen use and the risk of endometrial cancer

To date, no prospective studies have explored the relationship between the use of aspirin, other nonsteroidal anti-inflammatory medications (NSAID), and acetaminophen and endometrial adenocarcinoma. Of the 82,971 women enrolled in a prospective cohort study, 747 developed medical record-confirmed invasive endometrial cancer over a 24-year period. Use of aspirin was ascertained from 1980 to 2004, and for other NSAIDs and acetaminophen, from 1990 to 2004. Cox regression models calculated multivariate relative risks (MV RR), controlling for body mass index (BMI), postmenopausal hormone (PMH) use, and other endometrial cancer risk factors. Currency, duration, and quantity of aspirin were not associated with endometrial cancer risk overall [current use: MV RR, 1.03; 95% confidence interval (CI) 0.83-1.27; >10 years of use: MV RR, 1.01; 95% CI, 0.78-1.30; and cumulative average >7 tablets per week: (MV RR, 1.10; 95% CI, 0.84-1.44)]. However, stratified analyses showed that a lower risk of endometrial cancer among obese (BMI, >or=30 kg/m(2)) women was seen with current aspirin use (MV RR, 0.66; 95% CI, 0.46-0.95). The greatest risk reduction for current aspirin users was seen in postmenopausal obese women who had never used PMH (MV RR, 0.43; 95% CI, 0.26-0.73). The use of other NSAIDs or acetaminophen was not associated with endometrial cancer. Our data suggest that use of aspirin or other NSAIDs does not play an important role in endometrial cancer risk overall. However, risk was significantly lower for current aspirin users who were obese or who were postmenopausal and had never used PMHs; these subgroup findings require further confirmation.

Inflammatory status influences aromatase and steroid receptor expression in endometriosis

Aberrant up-regulation of aromatase in eutopic endometrium and implants from women with endometriosis has been reported. Aromatase induction may be mediated by increased cyclooxygenase-2 (COX-2). Recently, we demonstrated that progesterone receptor (PR)-A and PR-B serve an antiinflammatory role in the uterus by antagonizing nuclear factor kappaB activation and COX-2 expression. PR-C, which antagonizes PR-B, is up-regulated by inflammation. Although estrogen receptor alpha (ERalpha) is implicated in endometriosis, an antiinflammatory role of ERbeta has been suggested. We examined stage-specific expression of aromatase, COX-2, ER, and PR isoform expression in eutopic endometrium, implants, peritoneum, and endometrioma samples from endometriosis patients. Endometrial and peritoneal biopsies were obtained from unaffected women and those with fibroids. Aromatase expression in eutopic endometrium from endometriosis patients was significantly increased compared with controls. Aromatase expression in endometriosis implants was markedly increased compared with eutopic endometrium. Aromatase mRNA levels were increased significantly in red implants relative to black implants and endometrioma cyst capsule. Moreover, COX-2 expression was increased in implants and in eutopic endometrium of women with endometriosis as compared with control endometrium. As observed for aromatase mRNA, the highest levels of COX-2 mRNA were found in red implants. The ratio of ERbeta/ERalpha mRNA was significantly elevated in endometriomas compared with endometriosis implants and eutopic endometrium. Expression of PR-C mRNA relative to PR-A and PR-B mRNA was significantly increased in endometriomas compared with eutopic and control endometrium. PR-A protein was barely detectable in endometriomas. Thus, whereas PR-C may enhance disease progression, up-regulation of ERbeta may play an antiinflammatory and opposing role.

Angiogenesis and antiangiogenic therapy in endometriosis

Endometriosis, the presence of endometrium-like tissue outside of the uterine cavity, is a common disease among women of reproductive age. Typical symptoms include abdominal pain and painful menstruation. In addition, endometriosis is associated with reduced fertility. Current treatment modalities, the surgical removal of endometriotic lesions and the hormonal suppression of estrogen are associated with significant morbidity, side-effects and recurrence rates. Despite uncertainties about the pathophysiology of the disease it has recently become apparent that angiogenesis plays a pivotal role in endometriosis. This review focuses on a multitude of factors involved in the angiogenic phenotype of endometriosis demonstrating that many biological systems such as the immune system and steroid hormones are closely connected to angiogenic pathways in this disease. In addition, experimental and clinical data are discussed that concentrate on the inhibition of angiogenesis as a novel therapeutic approach for endometriosis.

Role of cyclooxygenase-2 in tetrahydrobiopterin-induced dopamine oxidation

Dopamine is considered one of the main contributing factors in the induction of oxidative stress and selective dopaminergic neurodegeneration in Parkinson's disease. We have previously reported that tetrahydrobiopterin (BH4) leads to dopamine oxidation and renders dopamine-producing cells vulnerable. In the present study, we found that BH4 selectively upregulates cyclooxygenase-2 (COX-2) expression in dopaminergic cells. BH4 caused an induction of COX-2 mRNA, and a critical regulatory motif for BH4-induced transcriptional activation of COX-2 is CRE/AP-1. COX-2 can oxidize dopamine and cause oxidative stress, which is evidenced by the findings that significant increase in dopamine-chrome formation and protein carbonyl contents by BH4-induced COX-2 up-regulation, and the increases are abolished by COX-2 selective inhibitor meloxicam. Increased COX-2 promotes dopaminergic neurodegeneration in both SH-SY5Y cells and rat mesencephalic neurons. These data suggest that BH4-induced COX-2 expression is responsible for dopamine oxidation, leading to the preferential vulnerability of dopaminergic cells in Parkinson's disease.

Nuclear factor-kappa B is constitutively activated in peritoneal endometriosis

Red (active), black and white endometriotic lesions are characteristic of peritoneal endometriosis. The transcription factor nuclear factor-kappa B (NF-kappaB) activates proinflammatory, proliferative and antiapoptotic genes in many cell types. To determine whether NF-kappaB is activated in peritoneal endometriosis in women, and further ascertain the differential inflammatory status of endometriotic implants, NF-kappaB activation and intercellular adhesion molecule (ICAM)-1 expression were investigated in peritoneal endometriotic lesions according to their type. Furthermore, p65 and p50 subunits of active NF-kappaB dimers were evaluated in endometriotic lesions to gain some insight into NF-kappaB-implicated pathways. Thirty-six biopsies of peritoneal endometriotic lesions were analyzed. Constitutive NF-kappaB activation, involving p65- and p50-containing dimers, was demonstrated in peritoneal endometriotic lesions by electrophoretic mobility shift assays and supershift analyses, as well as NF-kappaB (p65) DNA-binding activity immunodetection assays. NF-kappaB activation and ICAM-1 expression (evaluated by immunoblotting) were significantly higher in red lesions than black lesions, whereas IkappaBalpha (NF-kappaB inhibitory protein) expression was constant, as shown by western blot analysis. This is the first study to demonstrate constitutive NF-kappaB activation in peritoneal endometriosis in women. NF-kappaB activation and ICAM-1 expression in red lesions confirm the more extensive inflammatory pattern of these lesions compared with black lesions. The involvement of p50/p65 dimers in NF-kappaB activation suggests implication of the classic NF-kappaB activation pathway, making it an attractive therapeutic target in endometriosis.

The involvement of nuclear factor-kappa B in cyclooxygenase-2 overexpression in murine colon cancer cells transduced with herpes simplex virus thymidine kinase gene

We have previously reported that transduction of murine colon cancer cells (MC38) with herpes simplex virus thymidine kinase (HSV-tk) gene results in a significant enhancement of tumor growth rate in vivo and overexpression of cyclooxygenase-2 (COX-2). Our current study aimed to investigate the involvement of nuclear factor-kappa B (NF-kappaB), a pivotal transcriptional regulator of COX-2, in the upregulation of COX-2 expression by HSV-tk. It was found that HSV-tk gene transduction of MC38 cells results in significantly enhanced NF-kappaB activity, increased phosphorylation and degradation of inhibitor-kappa Balpha (IkappaBalpha) and enhanced translocation of NF-kappaB to the nucleus. Treatment of HSV-tk-transduced MC38 cells with sulfasalazine, a potent NF-kappaB inhibitor, led to dose-dependent inhibition of NF-kappaB activity, IkappaB phosphorylation and nuclear translocation of NF-kappaB, accompanied by significantly decreased COX-2 expression and reduced release of prostaglandin E2. Transient transfection experiments with COX-2 promoter constructs fused to luciferase reporter gene revealed that mutation in NF-kappaB-responsive element of COX-2 promoter significantly reduced promoter activity in HSV-tk-transduced MC38 and COS-7 cells, whereas it had no effect on promoter activity in the respective wild-type cells. At last, it was found that HSV-tk gene transduction causes significant enhancement of NF-kappaB activity and COX-2 expression in two additional tumor cell lines, 9L and T24. These findings suggest that HSV-tk gene transduction results in NF-kappaB pathway activation, which is essential for COX-2 overexpression by HSV-tk.

Hypoxia induced by benign intestinal epithelial cells is associated with cyclooxygenase-2 expression in stromal cells through AP-1-dependent pathway

Cyclooxygenase-2 (COX-2) plays important roles in tumor development. Especially in the early-stage colorectal tumors, COX-2 expression is often observed in the tumor stroma. However, the mechanism regulating such stromal expression of COX-2 remains unknown. In the present study, we simulated the indirect interaction between epithelial cells and stromal cells in the process of colorectal tumor development using an in vitro co-culture model in which NIH3T3 fibroblasts were co-cultured with 'sparsely' or 'densely' populated intestinal epithelial cells, Intestine-407 as a model of premalignant or benign intestinal epithelial cells, and DLD-1 and Caco-2 as models of malignant epithelial cells. COX-2 expression in NIH3T3 fibroblasts was upregulated when co-cultured with the 'dense' epithelial cells regardless of their character. Interestingly, there was pericellular hypoxia in the vicinity of NIH3T3 fibroblasts when co-cultured with 'dense' epithelial cells, and the recovery of the partial pressure of oxygen level resulted in the reduction of enhanced COX-2 expression only in NIH3T3 fibroblasts co-cultured with 'dense' Intestine-407 cells. Furthermore, COX-2 expression was also reduced by the inhibition of transcription factor AP-1. Thus, pericellular hypoxia of the stromal cells caused by densely populated epithelial cells may be one of the potent COX-2 enhancers before completion of malignant transformation during intestinal tumor development.

Inflammation and Endometrial Cancer: A Hypothesis

Endometrial cancer is the most common gynecologic malignancy in the United States. Substantial epidemiologic data implicate an imbalance of estrogens and progestogens in the etiology of this disease. We propose that inflammation also plays a role in endometrial cancer development. Emerging laboratory data suggest that elevated levels of prostaglandin E(2) may underlie the transformation of normal endometrium to neoplastic tissue and that in vitro nonsteroidal anti-inflammatory drugs may inhibit endometrial cancer cell growth. In this review, we suggest that the risk factors for endometrial cancer--unopposed estrogens, anovulation, polycystic ovary syndrome, excessive menstruation, early menarche, and late menopause--may be viewed as factors increasing the exposure of the endometrium to inflammation, whereas pregnancy and smoking, two likely protective factors, have the opposite effect. Chronic inflammation can induce rapid cell division, increasing the possibility for replication error, ineffective DNA repair, and subsequent mutations. A proinflammatory milieu can also directly increase estrogen production. Hence, inflammation may work in conjunction with or in addition to estrogen exposure in the development of endometrial cancer.

Nitric oxide upregulates the cyclooxygenase-2 expression through the cAMP-response element in its promoter in several cancer cell lines

We previously showed that nitric oxide (NO) induces overexpression of cyclooxygenase-2 (COX-2) and production of prostaglandin E(2) in cancer cells. Here, we investigated the mechanisms by which NO induces COX-2 expression in cancer cells. We found that the cAMP-response element (CRE) is a critical factor in NO-induced COX-2 expression in all cells tested. We found that in cancer cells, three transcription factors (TFs) - cAMP response element-binding protein (CREB), activating transcription factor-2 (ATF-2) and c-jun, bound the CRE in the COX-2 promoter, and their activities were increased by addition of the NO donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP). NO-induced activation of soluble guanylate cyclase (sGC), p38 and c-Jun NH(2)-terminal kinase (JNK) upregulated the three TFs, leading to COX-2 overexpression. Addition of dibutyryl-cGMP (db-cGMP) induced COX-2 expression in a manner similar to SNAP; this induction was blocked by a p38 inhibitor (SB202190), but not by a JNK inhibitor (SP600125). NO-induced cGMP was found to activate CREB and ATF-2 in a p38, but not c-jun-dependent manner, while NO induced JNK in a cGMP-independent manner, leading to subsequent activation of c-jun and ATF-2. These results suggest that the low concentrations of endogenous NO present in cancer cell may induce the expression of many genes, including COX-2, which promotes the growth and survival of tumor cells.

Expression of cyclooxygenase-2 (COX-2), receptors for estrogen (ER), and progesterone (PR), p53, ki67, and neu protein in endometrial cancer

OBJECTIVE

We aimed at investigating by immunohistochemistry the relationship between cyclooxygenase-2 (COX-2) and estrogen (ER), and progesterone (PR) receptors in a single institution series of 90 primary untreated endometrial cancer patients. The simultaneous assessment of p53 protein, ki67, and neu protein has been carried out.

METHODS

Immunohistochemistry was performed on paraffin-embedded sections by using rabbit polyclonal antiserum against human COX-2, anti-ER (clone 1D5), and anti-PR (clone 1A6) monoclonal antibodies, anti ki67 (clone MIB-1) and p53 (clone DO-7), and polyclonal antibody anti human c-erbB2/neu.

RESULTS

There was no difference in the distribution of COX-2, p53, and neu positive cases according to ER or PR positivity, while the percentage of ki67 positive endometrial tumors was significantly higher in ER negative versus ER positive tumors (54.5% versus 31.6%, P value = 0.044). ER and PR positive tumors showed a statistically significant association with clinicopathological parameters of better clinical outcome. There was no clear association between COX-2 positivity and any of the clinicopathological features. The percentage of ki67, p53, and neu positive tumors was found to be strictly related to more aggressive features. Only advanced stage of disease was found to be a predictor of poor prognosis (P value = 0.034). None of the biological parameters examined was shown to be associated with patient outcome.

CONCLUSIONS

We showed that COX-2 expression is not correlated with ER, PR, p53, and neu, thus suggesting that COX-2-mediated activities may follow independent pathways. Our findings provide the rationale to design trials based on the combination of antihormones with inhibitors of COX-2 and neu in recurrent/metastatic endometrial cancer.

Enhanced expressions of endometrial tumour necrosis factor alpha and its receptors during early pregnancy in bonnet monkeys

Tumour necrosis factor alpha (TNF-alpha), a pro-inflammatory cytokine may play an active role in stimulating inflammatory reactions during pregnancy. However, the expression of endometrial TNF-alpha has not been investigated especially during early pregnancy, a phenomenon invariably accompanied by inflammatory reaction. In the present study, the endometrial expressions of TNF-alpha and its receptors (TNFR1 and TNFR2) during early pregnancy, when the embryo lies free in the zona hatched state in the uterine lumen, were analyzed by immunohistochemistry. The endometrial expressions of TNF-alpha, TNFR1 and TNFR2 were found to be significantly up-regulated (p < 0.05) in the glandular epithelium on day 6 post-ovulation in pregnant animals. The alteration in the expression of these molecules may contribute to the induction of local inflammatory reactions during implantation.

Regulation of aromatase expression in estrogen-responsive breast and uterine disease: from bench to treatment

A single gene encodes the key enzyme for estrogen biosynthesis termed aromatase, inhibition of which effectively eliminates estrogen production. Aromatase inhibitors successfully treat breast cancer and endometriosis, whereas their roles in endometrial cancer, uterine fibroids, and aromatase excess syndrome are less clear. Ovary, testis, adipose tissue, skin, hypothalamus, and placenta express aromatase normally, whereas breast and endometrial cancers, endometriosis, and uterine fibroids overexpress aromatase and produce local estrogen that exerts paracrine and intracrine effects. Tissue-specific promoters distributed over a 93-kilobase regulatory region upstream of a common coding region alternatively control aromatase expression. A distinct set of transcription factors regulates each promoter in a signaling pathway- and tissue-specific manner. Three mechanisms are responsible for aromatase overexpression in a pathologic tissue versus its normal counterpart. First, cellular composition is altered to increase aromatase-expressing cell types that use distinct promoters (breast cancer). Second, molecular alterations in stromal cells favor binding of transcriptional enhancers versus inhibitors to a normally quiescent aromatase promoter and initiate transcription (breast/endometrial cancer, endometriosis, and uterine fibroids). Third, heterozygous mutations, which cause the aromatase coding region to lie adjacent to constitutively active cryptic promoters that normally transcribe other genes, result in excessive estrogen formation owing to the overexpression of aromatase in many tissues.

Aromatase and other steroidogenic genes in endometriosis: translational aspects

Endometriosis is a common, chronic and estrogen-dependent gynaecological disorder associated with pelvic pain and infertility. In addition to, or perhaps as a consequence of, immune, environmental and genetic factors, endometriotic lesions show high estradiol (E(2)) biosynthesis and low E(2) inactivation compared with normal endometrium. Current medical therapies of pain, which aim to lower circulating E(2) concentrations, are not effective in at least half of these patients. We and others recently demonstrated the expression of a few steroidogenic genes in endometriosis. The most important genes in this group are steroidogenic acute regulatory protein (StAR) and aromatase. Both are essential for E(2) production. Prostaglandin E(2) (PGE(2)) is the most potent known stimulator of both StAR and aromatase. PGE(2) production in endometriosis is up-regulated by increased levels of the enzyme cyclo-oxygenase-2 (COX-2) in this tissue. COX-2 in turn is stimulated by E(2), interleukin-1beta (IL-1beta) and PGE(2) itself in endometrial and endometriotic cells. Thus, there is a positive feedback loop that favours continuous formation of E(2) and PGE(2) in endometriosis. These basic findings led to recent phase-II studies employing aromatase inhibitors in the treatment of endometriosis. Aromatase inhibitors treat both postmenopausal and premenopausal endometriosis at least as effectively as the existing medical treatments. In premenopausal women, we and others administered aromatase inhibitors in combination with an ovarian-suppressant treatment. In this review, we emphasize the most recent basic studies in detail and provide a short summary of recent clinical trials.

Increased PGE2 levels in nonmalignant mucosa adjacent to squamous cell carcinoma of the head and neck

OBJECTIVE

The cyclooxygenases (COX) 1 and 2 are the rate-limiting enzymes of prostaglandin E(2) (PGE(2)) synthesis, and the upregulation of COX-2 has been reported in tumors of different origins. The aim of our study was to quantify the PGE(2) expression in squamous cell carcinoma and surrounding mucosa, to analyze the potential of acetylsalicylic acid (ASA) for reducing PGE(2) levels in these tissues, and to improve our understanding of potential tumor-derived stimulation of surrounding mucosa by PGE(2).

STUDY DESIGN AND SETTING

Intracellular PGE(2) levels in primary head and neck squamous cell carcinoma (HNSCC) and the surrounding mucosa at 1 and 2 cm distance were analyzed ex vivo by ELISA. Subsequently, we treated in vitro tumor and normal mucosal cells from turbinates with recombinant PGE(2) and ASA, and quantified intracellular PGE(2) levels.

RESULTS

We observed high PGE(2) levels in the tumor samples and in tumor-surrounding mucosa. The addition of PGE(2) and arachidonic acid to tumor cell cultures resulted in no further increase in intracellular PGE(2) levels, while ASA reduced PGE(2) levels by up to 40%. In normal epithelial cell cultures, less PGE(2) (6% of that found in the tumor cells) was expressed, but stimulation with PGE(2) resulted in levels comparable to those of the tumor samples.

CONCLUSION AND SIGNIFICANCE

We conclude that HNSCC and the surrounding mucosa express high levels of PGE(2). This expression is reduced efficiently by ASA. We propose a stimulation of PGE(2) expression in the epithelium surrounding HNSCC by tumor-derived PGE(2) with a potential impact on tumor growth.

Correlation of cyclooxygenase-2 (COX-2) and aromatase expression in human endometrial cancer: tissue microarray analysis

OBJECTIVE

The objective of this study was to compare the prevalence of cyclooxygenase-2 (COX-2), aromatase, and hormone receptor immunohistochemical (IHC) expression to well defined clinical-pathologic prognostic factors in a large group of surgically staged endometrial cancer patients.

STUDY DESIGN

A tissue microarray (TMA) was constructed from 336 separate specimens of endometrial cancer. IHC was performed for estrogen (ER) and progesterone (PR) receptor, COX-2, COX-1, and aromatase.

RESULTS

The majority of tumors expressed COX-2 (59%) and aromatase (65%). COX-2 staining significantly correlated with aromatase expression ( P < .014) but did not correlate with ER and PR. COX-2 expression was correlated with worsening histologic grade ( P < .026) and approached statistical significance for deep myometrial invasion ( P < .055). After applying multivariate analysis, no single IHC or combination of IHCs correlated with intrauterine poor prognostic factors or advanced stage. Only myometrial invasion >50% (OR 6.98, P < .001) and nonendometrioid histology (OR 4.933, P < .001) were predictive of advanced stage after multivariate analysis.

CONCLUSION

COX-2 and aromatase are expressed in the majority of endometrial cancer patients. COX-2 expression was not associated with the great majority of surgical-pathologic prognostic factors. COX-2 expression did significantly correlate with aromatase expression, suggesting that intratumoral production of estrogen in endometrial cancer may be an important mechanism in tumorigenesis.

Nimesulide, a COX-2 inhibitor, does not reduce lesion size or number in a nude mouse model of endometriosis

BACKGROUND

Women with endometriosis have elevated levels of cyclooxygenase-2 (COX-2) in peritoneal macrophages and endometriotic tissue. Inhibition of COX-2 has been shown to reduce inflammation, angiogenesis and cellular proliferation. It may also downregulate aromatase activity in ectopic endometrial lesions. Ectopic endometrial establishment and growth are therefore likely to be suppressed in the presence of COX-2 inhibitors. We hypothesized that COX-2 inhibition would reduce the size and number of ectopic human endometrial lesions in a nude mouse model of endometriosis.

METHODS

The selective COX-2 inhibitor, nimesulide, was administered to estrogen-supplemented nude mice implanted with human endometrial tissue. Ten days after implantation, the number and size of ectopic endometrial lesions were evaluated and compared with lesions from a control group. Immunohistochemical assessment of vascular development and macrophage and myofibroblast infiltration in control and treated lesions was performed.

RESULTS

There was no difference in the number or size of ectopic endometrial lesions in control and nimesulide-treated nude mice. Nimesulide did not induce a visually identifiable difference in blood vessel development or macrophage or myofibroblast infiltration in nude mouse explants.

CONCLUSION

The hypothesized biological properties of COX-2 inhibition did not influence lesion number or size in the nude mouse model of endometriosis.

Direct and indirect effects of aldosterone on cyclooxygenase-2 and interleukin-6 expression in rat cardiac cells in culture and after myocardial infarction

Aldosterone contributes to cardiac failure, which is associated with induction of inflammatory mediators. Moreover, aldosterone was shown to induce a vascular inflammatory phenotype in the rat heart. Using Western blotting and/or real-time RT-PCR, we examined the effect of aldosterone on the expression of the proinflammatory molecules, cyclooxygenase-2 (COX-2), and IL-6 in neonatal rat ventricular cardiac myocytes and fibroblasts as well as in adult cardiomyocytes after myocardial infarction. In cardiomyocytes, aldosterone induced COX-2 but not IL-6 expression. After 4-18 h of stimulation with 1 microm aldosterone, a significant increase in COX-2 protein expression was observed, preceded by an increase of COX-2 mRNA levels. After 18 h treatment, 100 nm and 1 microm aldosterone increased COX-2 protein amount by 2- and 4-fold, respectively. Consistently, aldosterone increased by 2.5-fold prostaglandin E(2) secretion in cardiomyocytes. In cardiac fibroblasts, aldosterone increased neither COX-2 nor IL-6 mRNA expression. Interestingly, prostaglandin E(2) (100 nm) strongly induced both proinflammatory molecules in fibroblasts and cardiomyocytes. Our results indicate that aldosterone directly induces COX-2 expression in cardiomyocytes and suggest that the subsequent increase in prostaglandin secretion may act in an autocrine and/or paracrine manner inducing in turn COX-2 and IL-6 expression. In vivo, myocardial infarction strongly increased both COX-2 and IL-6 expression in ventricular cardiomyocytes. Administration of the aldosterone antagonist RU28318 completely prevented COX-2 induction by infarction and partially inhibited the increase in IL-6 mRNA. These data suggest that after myocardial infarction, mineralocorticoid receptor activity is responsible for COX-2 induction and indirectly participates in IL-6 expression in cardiomyocytes.

Estrogen up-regulates cyclooxygenase-2 via estrogen receptor in human uterine microvascular endothelial cells

OBJECTIVE

To investigate the effects of 17beta-estradiol (E(2)) on cyclooxygenase-2 (COX-2) expression and prostaglandin E(2) (PGE(2)) synthesis in primary human uterine microvascular endothelial cells (HUMEC).

DESIGN

Prospective study.

SETTING

Basic research laboratory at an academic medical center.

PATIENT(S)

Primary HUMEC of three women donors and primary human dermal microvascular endothelial cells of three women donors (as control), purchased from a third-party source.

INTERVENTION(S)

The HUMEC were cultured in specific media in a humidified atmosphere with 5% CO(2) at 37 degrees C.

MAIN OUTCOME MEASURE(S)

Measures of COX-2 mRNA and protein, PGE(2) production, and estrogen receptor alpha and beta mRNA and protein.

RESULT(S)

Treatment with E(2) (10(-10) to 10(-6) M) increased COX-2 mRNA levels by 2.3-fold to 2.4-fold in HUMEC. Treatment of HUMEC with E(2) (10(-8) M) resulted in a time-dependent increase of COX-2 mRNA levels. This was accompanied by a 2.8-fold increase in COX-2 protein level and a 1.5-fold increase in PGE(2) synthesis. Pretreatment of HUMEC with a selective COX-2 inhibitor, NS-398, abolished E(2)-induced PGE(2) synthesis, suggesting that E(2) specifically up-regulates COX-2 activity. The estrogen receptor antagonist ICI 182,780 fully reversed the stimulation of COX-2 mRNA and protein levels and PGE(2) synthesis by E(2). Interestingly, estrogen receptor beta mRNA and protein were abundant in HUMEC, whereas estrogen receptor alpha mRNA or protein was barely detectable.

CONCLUSION(S)

We conclude that various levels of E(2) can significantly increase COX-2 expression and PGE(2) synthesis in HUMEC via the estrogen receptor.

Mechanical stretch activates nuclear factor-kappaB, activator protein-1, and mitogen-activated protein kinases in lung parenchyma: implications in asthma

We investigated the effects of mechanical stretch and induced stimulation of lung parenchyma on the activation of proinflammatory transcription factors in normal mice and in a mouse model of asthma. Mechanical stretching of lung parenchyma led to increased activation of NF-kappaB and AP-1 transcription factors. Incubation of lung parenchyma with methacholine increased the activation of NF-kappaB, which was further augmented by stretch. Activation of NF-kappaB in response to mechanical stretch was associated with the phosphorylation and degradation of IkappaBalpha and the activation of IkappaB kinase. Stretch-induced activation of NF-kappaB involves activation of stretch-activated (SA) channels and the production of free radicals. Mechanical stretch and/or treatment with methacholine resulted in an increased activation of ERK1/2 and p38 MAP kinase, and the inhibition of the activity of these kinases partially blocked the stretch-induced NF-kappaB and AP-1 activation. A greater level of NF-kappaB and ERK1/2 activity was observed in the asthmatic mice, which was further increased by mechanical stretching. The level of cyclooxygenase-2, an NF-kappaB-regulated enzyme, was also higher in lung parenchyma from asthmatic mice than in normal mice. Our data suggest that mechanical stretching of lung parenchyma activates NF-kappaB and AP-1, at least in part, through the activation of MAP kinase signaling pathways.

IL-1beta-dependent activation of NF-kappaB mediates PGE2 release via the expression of cyclooxygenase-2 and microsomal prostaglandin E synthase

Prostaglandin (PG) E2 release is induced in pulmonary A549 cells by the NF-kappaB-activating stimuli interleukin-1beta (IL-1beta) and phorbol 12-myristate 13-acetate (PMA). Adenoviral over-expression of IkappaBalphaDeltaN, a dominant NF-kappaB inhibitor, prevents NF-kappaB-dependent transcription and was used to qualify the role of NF-kappaB in the release of PGE2. IkappaBalphaDeltaN repressed IL-1beta-induced, but not PMA-induced, cycloxygenase-2 (COX-2) and microsomal prostaglandin E synthase (mPGES) expression. These data conclusively demonstrate a substantial role for NF-kappaB in the co-ordinate induction of COX-2, mPGES and in the corresponding release of PGE2 by IL-1beta. However, other pathways are primarily responsible for PGE2 release induced by PMA.