Heightened expression of cyclooxygenase-2 and peroxisome proliferator-activated receptor-delta in human endometrial adenocarcinoma

Lipid metabolism reprogramming in endometrial cancer: biological functions and therapeutic implications

BACKGROUND

Endometrial cancer is one of the major gynecological cancers, with increasing incidence and mortality in the past decades. Emerging preclinical and clinical data have indicated its close association with obesity and dyslipidemia. Metabolism reprogramming has been considered as the hallmark of cancer, to satisfy the extensive need of nutrients and energy for survival and growth. Particularly, lipid metabolism reprogramming has aroused the researchers' interest in the field of cancer, including tumorigenesis, invasiveness, metastasis, therapeutic resistance and immunity modulation, etc. But the roles of lipid metabolism reprogramming in endometrial cancer have not been fully understood. This review has summarized how lipid metabolism reprogramming induces oncogenesis and progression of endometrial cancer, including the biological functions of aberrant lipid metabolism pathway and altered transcription regulation of lipid metabolism pathway. Besides, we proposed novel therapeutic strategies of targeting lipid metabolism pathway and concentrated on its potential of sensitizing immunotherapy and hormonal therapy, to further optimize the existing treatment modalities of patients with advanced/metastatic endometrial cancer. Moreover, we expect that targeting lipid metabolism plus hormone therapy may block the endometrial malignant transformation and enrich the preventative approaches of endometrial cancer.

CONCLUSION

Lipid metabolism reprogramming plays an important role in tumor initiation and cancer progression of endometrial cancer. Targeting the core enzymes and transcriptional factors of lipid metabolism pathway alone or in combination with immunotherapy/hormone treatment is expected to decrease the tumor burden and provide promising treatment opportunity for patients with advanced/metastatic endometrial cancer.

Peroxisome proliferator-activated receptors: Key regulators of tumor progression and growth

One of the main causes of death on the globe is cancer. Peroxisome-proliferator-activated receptors (PPARs) are nuclear hormone receptors, including PPARα, PPARδ and PPARγ, which are important in regulating cancer cell proliferation, survival, apoptosis, and tumor growth. Activation of PPARs by endogenous or synthetic compounds regulates tumor progression in various tissues. Although each PPAR isotype suppresses or promotes tumor development depending on the specific tissues or ligands, the mechanism is still unclear. PPARs are receiving interest as possible therapeutic targets for a number of disorders. Numerous clinical studies are being conducted on PPARs as possible therapeutic targets for cancer. Therefore, this review will focus on the existing and future uses of PPARs agonists and antagonists in treating malignancies. PubMed, Science Direct, and Scopus databases were searched regarding the effect of PPARs on various types of cancers until the end of May 2023. The results of the review articles showed the therapeutic influence of PPARs on a wide range of cancer on in vitro, in vivo and clinical studies. However, further experimental and clinical studies are needed to be conducted on the influence of PPARs on various cancers.

PPARs in Clinical Experimental Medicine after 35 Years of Worldwide Scientific Investigations and Medical Experiments

This year marks the 35th anniversary of Professor Walter Wahli's discovery of the PPARs (Peroxisome Proliferator-Activated Receptors) family of nuclear hormone receptors. To mark the occasion, the editors of the scientific periodical Biomolecules decided to publish a special issue in his honor. This paper summarizes what is known about PPARs and shows how trends have changed and how research on PPARs has evolved. The article also highlights the importance of PPARs and what role they play in various diseases and ailments. The paper is in a mixed form; essentially it is a review article, but it has been enriched with the results of our experiments. The selection of works was subjective, as there are more than 200,000 publications in the PubMed database alone. First, all papers done on an animal model were discarded at the outset. What remained was still far too large to describe directly. Therefore, only papers that were outstanding, groundbreaking, or simply interesting were described and briefly commented on.

The usefulness of p16 and COX-2 expression on the prediction of progression to endometrial cancer

OBJECTIVES

Endometrial cancer (EC) is the most commonly diagnosed gynecological cancer. Endometrial hyperplasia (EH) is a more common diagnosis than EC. Endometrial hyperplasia is found in approximately 1.5% of all women presenting with abnormal bleeding. Endometrial hyperplasia progresses to EC, and especially, cancer risk increases in cases with atypical hyperplasia. p16, one of the tumor suppressor proteins involved in the cell cycle, and COX-2, one of the key enzymes of prostaglandin synthesis, are important markers for the diagnosis of both EH and EC. There is lack of consensus in the classification, diagnosis and treatment of EH. The subject of changes in the cell cycle in the progression of endometrial pathologies may help to identify and prevent these affected pathways in the treatment stage. The aim of this study is to investigate the expression of p16 and COX-2 during the development of EC from EH.

MATERIAL AND METHODS

We investigated COX-2 and P16 expressions in patients with proliferative endometrium, complex/simple endometrial hyperplasia and endometrioid adenocarcinoma.

RESULTS

p16 expression increased in EH and EC (p<0.001). COX-2 expression was increased in endometrial cancer compared to other groups, but this increase was not found to be statistically significant. Although p16 and COX-2 expression were increased in patients with advanced grade/stage, lymphovascular invasion, and >50% of myometrial invasion, this increase was not statistically significant.

CONCLUSIONS

More detailed studies are needed to investigate the prognostic significance of the COX-2 molecule. COX-2 might be a potential biomarker for the prognosis of endometrial cancer and a potential therapeutic target for EC treatment. Also, it might be used to prevent the progression of precursor lesions to invasive EC.

Tissue-Specific RNA Localization in the Uterus During Implantation, Decidualization and Placentation: Technical Nuances of Various Labeling Approaches

In situ hybridization (ISH) is a sensitive method used to localize a specific sequence of DNA or RNA in biological samples, including cells, tissue sections or whole organs. RNA ISH can be used to determine spatial gene expression using a single-stranded probe with a reverse-complementary sequence. Cell-specific gene expression has been studied using mRNA and protein levels. Signals produced by RNA probes are usually more specific than those produced by antibodies in immunostaining. Currently, ISH is the most widely used method to localize mRNA molecules. Traditionally, probes were labeled with radioactive isotopes, but the cumbersome procedures and potential health risk limit their acceptance. Recently, probes labeled with nonradioactive materials including digoxigenin, biotin and various fluorophores have been developed. The tyramide signal amplification system further enhances the sensitivity of detection. These methods have been applied in numerous studies in various tissues including reproductive organs. This article details three methods of RNA in situ hybridization: radioactive in situ hybridization, digoxigenin in situ hybridization, and digoxigenin-tyramide signal amplification fluorescein in situ hybridization. The pros and cons of each protocol are discussed. © 2023 Wiley Periodicals LLC. Basic Protocol 1: Radioactive in situ hybridization (radioactive-ISH) Basic Protocol 2: Digoxigenin in situ hybridization (DIG-ISH) Basic Protocol 3: Digoxigenin-tyramide signal amplification fluorescein in situ hybridization (DIG-TSA-FISH).

The Role of Peroxisome Proliferator-Activated Receptors in Endometrial Cancer

Endometrial carcinoma is the most common malignant tumor of the female genital tract in the United States. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptor proteins which regulate gene expression. In order to investigate the role of PPARs in endometrial cancer, we conducted a literature review using the MEDLINE and LIVIVO databases and were able to identify 27 relevant studies published between 2000 and 2023. The PPARα and PPARβ/δ isoforms seemed to be upregulated, whereas PPARγ levels were reported to be significantly lower in endometrial cancer cells. Interestingly, PPAR agonists were found to represent potent anti-cancer therapeutic alternatives. In conclusion, PPARs seem to play a significant role in endometrial cancer.

NF-қB and COX-2 Relation Between Endometrial Cancer and the Clinicopathological Parameters

Objective: Our study examines nuclear factor kappa B (NF-қB) and cyclooxygenase-2 (COX-2) polymorphisms in the most common gynecological cancer type, endometrial cancer, and the relationship between disease parameters and these polymorphisms. Methods: In our patient group; while 109 endometrial cancer patients were examined and treated in the Department of Gynecology and Obstetrics, Istanbul Medical Faculty, and 106 healthy women without the disease were included in the control group. DNA of blood samples taken from all groups were isolated; COX-2 765C> G and COX-2 1195A> G polymorphisms were studied with NF-қB-94 ins / delATTG. Genotypes analyzed using the PCR-based restriction fragment length polymorphisms (RFLP) method were investigated in terms of the relationship between endometrial cancer susceptibility and endometrial cancer disease parameters. Results in SPSS 17 program; Student’s t-tests were analyzed using Anova, Fisher’s exact, and Chi-square tests. Results: NF-қB D + and DD genotype, COX-2 765 G + and GG genotype, and COX-2 1195 AA genotype were found to be significantly more common in the endometrial cancer group compared to the control group (p

Oncopreventive and oncotherapeutic potential of licorice triterpenoid compound glycyrrhizin and its derivatives: Molecular insights

Licorice (Glycyrrhiza glabra) is a well-known natural herb used to treat different ailments since ancient times. Glycyrrhizin (GL), which is the primary triterpenoid compound of licorice extract, has been known to have broad-spectrum pharmacological effects. GL is cleaved into glucuronide and the aglycone, glycyrrhetinic acid (GA), which exists in two stereoisomeric forms: 18α- and 18β-GA. It is well documented that GL and GA have great potential as anti-inflammatory, anticancer, antiviral, anti-diabetic, antioxidant, and hepatoprotective agents. Studies undertaken during the coronavirus disease 2019 pandemic suggest that GL is effective at inhibiting the viral replication of severe acute respiratory syndrome coronavirus 2. The anticancer effects of GL and GA involve modulating various signaling pathways, such as the phosphatase and tensin homolog/phosphatidylinositol 3-kinase/protein kinase B pathway, the mitogen-activated protein kinase, and the mammalian target of rapamycin/signal transducer and activator of transcription 3, which are mainly involved in regulating cancer cell death, oxidative stress, and inflammation. The potential of GL and GA in preventing cancer development and suppressing the growth and invasion of different cancer types has been reviewed in this paper. This review also provides molecular insights on the mechanism of action for the oncopreventive and oncotherapeutic effects of GL and its derivative, GA, which could help develop more specific forms of these agents for clinical use.

Progesterone Receptor Membrane Component (PGRMC)1 and PGRMC2 and Their Roles in Ovarian and Endometrial Cancer

Cancers of the female reproductive tract are both lethal and highly prevalent. For example, the five-year survival rate of women diagnosed with ovarian cancer is still less than 50%, and endometrial cancer is the fourth most common cancer in women with > 65,000 new cases in the United States in 2020. Among the many genes already established as key participants in ovarian and endometrial oncogenesis, progesterone receptor membrane component (PGRMC)1 and PGRMC2 have gained recent attention given that there is now solid correlative information supporting a role for at least PGRMC1 in enhancing tumor growth and chemoresistance. The expression of PGRMC1 is significantly increased in both ovarian and endometrial cancers, similar to that reported in other cancer types. Xenograft studies using human ovarian and endometrial cancer cell lines in immunocompromised mice demonstrate that reduced expression of PGRMC1 results in tumors that grow substantially slower. While the molecular underpinnings of PGRMCs' mechanisms of action are not clearly established, it is known that PGRMCs regulate survival pathways that attenuate stress-induced cell death. The objective of this review is to provide an overview of what is known about the roles that PGRMC1 and PGRMC2 play in ovarian and endometrial cancers, particularly as related to the mechanisms through which they regulate mitosis, apoptosis, chemoresistance, and cell migration.

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.

Integrated eicosanoid lipidomics and gene expression reveal decreased prostaglandin catabolism and increased 5-lipoxygenase expression in aggressive subtypes of endometrial cancer

Eicosanoids comprise a diverse group of bioactive lipids which orchestrate inflammation, immunity, and tissue homeostasis, and whose dysregulation has been implicated in carcinogenesis. Among the various eicosanoid metabolic pathways, studies of their role in endometrial cancer (EC) have very much been confined to the COX-2 pathway. This study aimed to determine changes in epithelial eicosanoid metabolic gene expression in endometrial carcinogenesis; to integrate these with eicosanoid profiles in matched clinical specimens; and, finally, to investigate the prognostic value of candidate eicosanoid metabolic enzymes. Eicosanoids and related mediators were profiled using liquid chromatography-tandem mass spectrometry in fresh frozen normal, hyperplastic, and cancerous (types I and II) endometrial specimens (n = 192). Sample-matched epithelia were isolated by laser capture microdissection and whole genome expression analysis was performed using microarrays. Integration of eicosanoid and gene expression data showed that the accepted paradigm of increased COX-2-mediated prostaglandin production does not apply in EC carcinogenesis. Instead, there was evidence for decreased PGE₂ /PGF_2α inactivation via 15-hydroxyprostaglandin dehydrogenase (HPGD) in type II ECs. Increased expression of 5-lipoxygenase (ALOX5) mRNA was also identified in type II ECs, together with proportional increases in its product, 5-hydroxyeicosatetraenoic acid (5-HETE). Decreased HPGD and elevated ALOX5 mRNA expression were associated with adverse outcome, which was confirmed by immunohistochemical tissue microarray analysis of an independent series of EC specimens (n = 419). While neither COX-1 nor COX-2 protein expression had prognostic value, low HPGD combined with high ALOX5 expression was associated with the worst overall and progression-free survival. These findings highlight HPGD and ALOX5 as potential therapeutic targets in aggressive EC subtypes. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

New concepts for an old problem: the diagnosis of endometrial hyperplasia

BACKGROUND

Endometrial hyperplasia (EH) is a uterine pathology representing a spectrum of morphological endometrial alterations. It is predominantly characterized by an increase in the endometrial gland-to-stroma ratio when compared to normal proliferative endometrium. The clinical significance of EH lies in the associated risk of progression to endometrioid endometrial cancer (EC) and 'atypical' forms of EH are regarded as premalignant lesions. Traditional histopathological classification systems for EH exhibit wide and varying degrees of diagnostic reproducibility and, as a consequence, standardized patient management can be challenging.

OBJECTIVE AND RATIONALE

EC is the most common gynaecological malignancy in developed countries. The incidence of EC is rising, with alarming increases described in the 40-44-year-old age group. This review appraises the current EH classification systems used to stratify women at risk of malignant progression to EC. In addition, we summarize the evidence base regarding the use of immunohistochemical biomarkers for EH and discuss an emerging role for genomic analysis.

SEARCH METHODS

PubMed, Medline and the Cochrane Database were searched for original peer-reviewed primary and review articles, from January 2000 to January 2016. The following search terms were used: 'endometrial hyperplasia', 'endometrial intraepithelial neoplasia', 'atypical hyperplasia', 'complex atypical hyperplasia', 'biomarker', 'immunohistochemistry', 'progression', 'genomic', 'classification' and 'stratification'.

OUTCOMES

Recent changes to EH classification reflect our current understanding of the genesis of endometrioid ECs. The concept of endometrial intraepithelial neoplasia (EIN) as a mutationally activated, monoclonal pre-malignancy represents a fundamental shift from the previously held notion that unopposed oestrogenic stimulation causes ever-increasing hyperplastic proliferation, with accumulating cytological atypia that imperceptibly leads to the development of endometrioid EC. Our review highlights several key biomarker candidates that have been described as both diagnostic tools for EH and markers of progression to EC. We propose that, moving forwards, a 'panel' approach of combinations of the immunohistochemical biomarkers described in this review may be more informative since no single candidate can currently fill the entire role.

WIDER IMPLICATIONS

EC has historically been considered a predominantly postmenopausal disease. Owing in part to the current unprecedented rates of obesity, we are starting to see signs of a shift towards a rising incidence of EC amongst pre- and peri-menopausal woman. This creates unique challenges both diagnostically and therapeutically. Furthering our understanding of the premalignant stages of EC development will allow us to pursue earlier diagnosis and facilitate appropriate stratification of women at risk of developing EC, permitting timely and appropriate therapeutic interventions.

microRNAs and Endometrial Pathophysiology

Embryo implantation requires a reciprocal interaction between the blastocyst and endometrium and is associated with complex regulatory mechanisms. Since their discovery, microRNAs became prominent candidates providing missing links for many biological pathways. In recent years, microRNAs were implicated as one of the important players in regulation of various biological and physiological endometrial related processes. This chapter aims to present recent knowledge pertaining to the diverse aspects of microRNAs in the embryo-endometrial relationship. We will focus on the role of microRNAs in decidualization and their part in natural and stimulated cycles. Next, we will present recent studies deliberating the role of microRNAs in recurrent pregnancy loss and in the important phenomenon of recurrent implantation failure. Lastly, demonstrating an important aspect of embryo implantation and invasion, we will outline few microRNA related shared pathways of implantation and carcinogenesis.

Mammalian target of rapamycin complex 1 and cyclooxygenase 2 pathways cooperatively exacerbate endometrial cancer

The underlying causes of endometrial cancer (EMC) are poorly understood, and treatment options for patients with advanced stages of the disease are limited. Mutations in the phosphatase and tensin homologue gene are frequently detected in EMC. Cyclooxygenase 2 (Cox2) and mammalian target of rapamycin complex 1 (mTORC1) are known downstream targets of the phosphatase and tensin homologue protein, and their activities are up-regulated in EMC. However, it is not clear whether Cox2 and mTORC1 are crucial players in cancer progression or whether they work in parallel or cooperatively. In this study, we used a Cox2 inhibitor, celecoxib, and an mTORC1 inhibitor, rapamycin, in mouse models of EMC and in human EMC cell lines to explore the interactive roles of Cox2 and mTORC1 signaling. We found that a combined treatment with celecoxib and rapamycin markedly reduces EMC progression. We also observed that rapamycin reduces Cox2 expression, whereas celecoxib reduces mTORC1 activity. These results suggest that Cox2 and mTORC1 signaling is cross-regulated and cooperatively exacerbate EMC.

Deciphering PDT-induced inflammatory responses using real-time FDG-PET in a mouse tumour model

Dynamic positron emission tomography (PET), combined with constant infusion of 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG), enables real-time monitoring of transient metabolic changesin vivo, which can serve to understand the underlying physiology.

Ligand-activated peroxisome proliferator-activated receptor β/δ modulates human endometrial cancer cell survival

Endometrial cancer is the fourth most common malignancy among women and is a major cause of morbidity contributing to approximately 8,200 annual deaths in the USA. Despite advances to the understanding of endometrial cancer, novel interventions for the disease are necessary given that many tumors become refractory to therapy. As a strategy to identify novel therapies for endometrial carcinoma, in this study, we examined the contribution of the peroxisome proliferator-activated receptor β/δ (PPARβ/δ) to endometrial cancer cell proliferation and apoptosis. We found that when activated with the highly selective PPARβ/δ agonists, GW0742 and GW501516, PPARβ/δ inhibited the proliferation and markedly induced the apoptosis of three endometrial cancer cell lines. The specificity of the PPARβ/δ-induced effects on cell proliferation and apoptosis was demonstrated using PPARβ/δ-selective antagonists and PPARβ/δ small interfering RNA in combination with PPARβ/δ-selective agonists. Furthermore, we showed that PPARβ/δ activation increased phosphatase and tensin homolog expression, which led to protein kinase B (AKT) and glycogen synthase kinase-3β (GSK3β) dephosphorylation, and increased β-catenin phosphorylation associated with its degradation. Overall, our data suggest that the antitumorigenic effect of PPARβ/δ activation in endometrial cancer is mediated through the negative regulation of the AKT/GSK3β/β-catenin pathway. These findings warrant further investigation of PPARβ/δ as a therapeutic target in endometrial cancer.

Expression of estrogen receptors (α, β), cyclooxygenase-2 and aromatase in normal endometrium and endometrioid cancer of uterus

PURPOSE

Endometrial cancer (EC) is one of the most common malignancies of the female genital tract, but the etiology, especially its metabolism is still investigated. The aim of this study was to evaluate the presence and relative expression of Estrogen Receptors (α, β), Cyclooxygenase-2 and Aromatase in both endometrial cancer and normal mucosa.

MATERIAL/METHODS

Two groups of women were selected for the study: 1) patients with endometrioid endometrial cancer (FIGO I; G1 - G3) (n=35) and 2) subjects with normal endometrial tissue (control group, n=29). The expression of Estrogen Receptors (ERα, β), Cyclooxygenase-2 (COX-2), Aromatase were estimated by Western blot analysis. Furthermore, the associations between FIGO classification (stage: Ia, Ib), tumor grade (G) and expression of ERα, β, COX-2, aromatase proteins were evaluated. Overall and disease-free survival curves were generated according to the Kaplan-Meier method. Median follow-up time of the patients examined in this study was 39 months.

RESULTS

The relative expression of each examined protein was markedly higher in the endometrial cancer tissue as compared to the healthy endometrium. The trends towards greater expression along with a tumor progression was noticed (FIGO stage: Ia vs. Ib). Analysis of endometrial cancer risk factors and their influence on survival curves showed only an inverse significant correlations between obesity (BMI: 36.2; n=21) and disease-free survival in EC group (p=0.00872), but there was no significant association between obesity and overall survival (p=0.358).

CONCLUSIONS

Endometrioid endometrial cancer shows relatively higher expression of either ER, COX-2 and aromatase comparing to healthy mucosa, suggesting their involvement in tumor development and progression.

CYP2W1, CYP4F11 and CYP8A1 polymorphisms and interaction of CYP2W1 genotypes with risk factors in Mexican women with breast cancer

Breast cancer (BCa) is the leading type of cancer in Mexican women. Genetic factors, such as single nucleotide polymorphisms (SNP) of P450 system, have been reported in BCa. In this report, and for the first time in the literature, we analyzed the rs3735684 (7021 G>A), rs11553651 (15016 G>T) and rs56195291 (60020 C>G) polymorphisms in the CYP2W1, 4F11 and 8A1 genes in patients with BCa and in healthy Mexican women to identify a potential association between these polymorphisms and BCa risk. Patients and controls were used for polymorphism analysis using an allelic discrimination assay with TaqMan probes and confirmed by DNA sequencing. Links with clinic-pathological characteristics were also analyzed. Statistical analysis was performed using the standard χ2 or Fisher exact test statistic. No significant differences were observed in the distributions of CYP2W1 (OR 8.6, 95%CI 0.43-172.5 P>0.05; OR 2.0, 95%CI 0.76-5.4, P>0.05) and CYP4F11 (OR 0.3, 95%CI 0.01-8.4 P>0.05) genotypes between the patients and controls. Only the CYP8A1 CC genotype was detected in patients with BCa and the controls. All polymorphism frequencies were in Hardy-Weinberg Equilibrium (HWE) in the controls (P>0.05). We found a significant association between BCa risk and smoking, use of oral contraceptives or hormonal replacement therapy (HRT), obesity, hyperglycemia, chronic diseases, family history of cancer and menopausal status in the population studied (P<0.05). Tobacco, oral contraceptive or HRT, chronic diseases and obesity or overweight were strongly associated with almost eight, thirty-five, nine and five-fold increased risk for BCa. Tobaco, obesity and hyperglycemia significantly increased the risk of BCa in the patients carrying variant genotypes of CYP2W1 (P<0.05). These results indicate that the CYP2W1 rs3735684, CYP4F11 rs11553651 and CYP8A1 rs56195291 SNPs are not a key risk factor for BCa in Mexican women. This study did not detect an association between the CYP2W1, 4F11 and 8A1 genes polymorphisms and BCa risk in a Mexican population. However, some clinico-pathological risk factors interact with CYP2W1 genotypes and modifies susceptibility to BCa.

Upregulation of ski in fibroblast is implicated in the peroxisome proliferator--activated receptor δ-mediated wound healing

BACKGROUND/AIM

Both peroxisome proliferator-activated receptor (PPAR) δ and Ski are investigate the interaction of PPARδ and Ski and this interaction-associated effect in wound healing.

METHODS

Effect of PPARδ activation on Ski expression was detected in rat skin fibroblasts by real-time PCR and western blot. Luciferase assay, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay were performed to identify the binding site of PPARδ in the promoter region of rat Ski gene. And the functional activity of PPARδ regulation to Ski was detected in fibroblast proliferation and rat skin wound healing model.

RESULTS

PPARδ agonist GW501516 upregulated Ski expression in a dose-dependent manner. Direct repeat-1 (DR1) response element locating at -865∼-853 in Ski promoter region was identified to mediate PPARδ binding to Ski and associated induction of Ski. Furthermore, PPARδ upregulated Ski to promote fibroblasts proliferation and rat skin wound repair, which could be largely blocked by pre-treated with Ski RNA interference.

CONCLUSION

This study demonstrates that Ski is a novel target gene for PPARδ and upregulation of Ski to promote fibroblast proliferation is implicated in the PPARδ-mediated wound healing.

The role of peroxisome proliferator-activated receptors in carcinogenesis and chemoprevention

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that are involved in regulating glucose and lipid homeostasis, inflammation, proliferation and differentiation. Although all of these functions might contribute to the influence of PPARs in carcinogenesis, there is a distinct need for a review of the literature and additional experimentation to determine the potential for targeting PPARs for cancer therapy and cancer chemoprevention. As PPAR agonists include drugs that are used for the treatment of metabolic diseases, a more complete understanding of the roles of PPARs in cancer will aid in determining any increased cancer risk for patients undergoing therapy with PPAR agonists.

Peroxisome proliferator-activated receptors modulate proliferation and angiogenesis in human endometrial carcinoma

Peroxisome proliferator-activated receptors (PPAR) and retinoid X receptors (RXR) are implicated in the development of several obesity-related cancers. Little is known of either the expression or function of PPARs and RXRs in endometrial cancer although this increasingly common disease is highly associated with both obesity and insulin resistance. We investigated the expression of PPAR and RXR subtypes in human endometrial cancers and normal endometrium with immunoblotting and immunohistochemistry and subsequently showed PPAR/RXR binding preferences by coimmunoprecipitation. To determine the functions of PPARs within the endometrium, we investigated proliferation, apoptosis, PTEN expression, and secretion of vascular endothelial growth factor (VEGF) in endometrial cell lines after reducing the expression of PPARα and PPARγ with antisense RNA. The functional effects of PPAR ligands were also investigated in vitro. We identified differential expression of PPAR and RXR subtypes in endometrial cancers and discovered that PPARγ expression correlated with expression of PTEN. PPARα activation influences endometrial cell growth and VEGF secretion. PPARγ activation reduces proliferation of endometrial cells via regulation of PTEN and appears to reduce VEGF secretion. We conclude that the PPAR/RXR pathway contribute to endometrial carcinogenesis by control of PTEN expression and modulation of VEGF secretion. We propose that PPAR ligands should be considered for clinical investigation in early phase studies of women with endometrial cancer.

From COX-2 inhibitor nimesulide to potent anti-cancer agent: synthesis, in vitro, in vivo and pharmacokinetic evaluation

Cyclooxygenase-2 (COX-2) inhibitor nimesulide inhibits the proliferation of various types of cancer cells mainly via COX-2 independent mechanisms, which makes it a good lead compound for anti-cancer drug development. In the presented study, a series of new nimesulide analogs were synthesized based on the structure-function analysis generated previously. Some of them displayed very potent anti-cancer activity with IC(50)s around 100 nM-200 nM to inhibit SKBR-3 breast cancer cell growth. CSUOH0901 (NSC751382) from the compound library also inhibits the growth of the 60 cancer cell lines used at National Cancer Institute Developmental therapeutics Program (NCIDTP) with IC(50)s around 100 nM-500 nM. Intraperitoneal injection with a dosage of 5  mg/kg/d of CSUOH0901 to nude mice suppresses HT29 colorectal xenograft growth. Pharmacokinetic studies demonstrate the good bioavailability of the compound.

Multiple Interactions between Peroxisome Proliferators-Activated Receptors and the Ubiquitin-Proteasome System and Implications for Cancer Pathogenesis

The peroxisome proliferator-activated receptors (PPAR) α, β/δ, and γ are ligand-activated nuclear receptors involved in a number of physiological processes, including lipid and glucose homeostasis, inflammation, cell growth, differentiation, and death. PPAR agonists are used in the treatment of human diseases, like type 2 diabetes and dyslipidemia, and PPARs appear as promising therapeutic targets in other conditions, including cancer. A better understanding of the functions and regulation of PPARs in normal and pathological processes is of primary importance to devise appropriate therapeutic strategies. The ubiquitin-proteasome system (UPS) plays an important role in controlling level and activity of many nuclear receptors and transcription factors. PPARs are subjected to UPS-dependent regulation. Interestingly, the three PPAR isotypes are differentially regulated by the UPS in response to ligand-dependent activation, a phenomenon that may be intrinsically connected to their distinct cellular functions and behaviors. In addition to their effects ongene expression, PPARs appear to affect protein levels and downstream pathways also by modulating the activity of the UPS in target-specific manners. Here we review the current knowledge of the interactions between the UPS and PPARs in light of the potential implications for their effects on cell fate and tumorigenesis.

Hypoxia and prostaglandin E receptor 4 signalling pathways synergise to promote endometrial adenocarcinoma cell proliferation and tumour growth

The prostaglandin endoperoxide synthase (PTGS) pathway is a potent driver of tumour development in humans by enhancing the biosynthesis and signalling of prostaglandin (PG) E(2). PTGS2 expression and PGE(2) biosynthesis is elevated in endometrial adenocarcinoma, however the mechanism whereby PTGS and PGE(2) regulate endometrial tumour growth is unknown. Here we investigated (a) the expression profile of the PGE synthase enzymes (PTGES, PTGES-2, PTGES-3) and PGE receptors (PTGER1-4) in endometrial adenocarcinomas compared with normal endometrium and (b) the role of PTGER4 in endometrial tumorigenesis in vivo. We found elevated expression of PTGES2 and PTGER4 and suppression of PTGER1 and PTGER3 in endometrial adenocarcinomas compared with normal endometrium. Using WT Ishikawa endometrial adenocarcinoma cells and Ishikawa cells stably transfected with the full length PTGER4 cDNA (PTGER4 cells) xenografted in the dorsal flanks of nude mice, we show that PTGER4 rapidly and significantly enhances tumour growth rate. Coincident with enhanced PTGER4-mediated tumour growth we found elevated expression of PTGS2 in PTGER4 xenografts compared with WT xenografts. Furthermore we found that the augmented growth rate of the PTGER4 xenografts was not due to enhanced angiogenesis, but regulated by an increased proliferation index and hypoxia. In vitro, we found that PGE(2) and hypoxia independently induce expression of PTGER4 indicating two independent pathways regulating prostanoid receptor expression. Finally we have shown that PGE(2) and hypoxia synergise to promote cellular proliferation of endometrial adenocarcinoma cells.

The soluble EP2 receptor FuEP2/Ex2 suppresses endometrial cancer cell growth in an orthotopic xenograft model in nude mice

Endometrial cancer is one of the most common gynecologic malignancies and many factors influence in its growth and development. As in many other types of cancer, prostaglandin E(2) (PGE(2)) is thought to be an accelerator of cell proliferation and endometrial cancer progression. In this study, we examined the effect of FuEP2/Ex2, a soluble decoy receptor for PGE(2) on growth of endometrial cancer cells. A stable transfectant expressing FuEP2/Ex2 was established from human endometrial cancer Ishikawa cells (Ish-FuEP2/Ex2). Ish-FuEP2/Ex2 cells expressed FuEP2/Ex2 mRNA and protein. Expression levels of E-prostanoid receptor 1 (EP1), EP2, EP3, EP4, and F-prostanoid receptor (FP) were almost the same in Ish-FuEP2/Ex2 and vector control cells. Growth rates of Ish-FuEP2/Ex2 under normal culture conditions were also similar to vector control cells, although PGE(2)-induced growth stimulation was completely inhibited in Ish-FuEP2/Ex2 or by Ish-FuEP2/Ex2 culture medium. Moreover, phosphorylation of extracellular signal-regulated kinase (ERK) and induction of cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), cyclin D1, and c-fos mRNA by PGE(2) were not observed in Ish-FuEP2/Ex2 and Ish-FuEP2/Ex2 culture medium-treated vector control cells, although they were found when treated with prostaglandin F(2α). An orthotopic xenograft model in athymic nude mice revealed that Ish-FuEP2/Ex2-injected mice had significantly decreased mean tumor area. The proportion of Ki-67-positive cells in the tumor lesion was also significantly lower in Ish-FuEP2/Ex2-injected mice. These findings suggest that an EP-targeting strategy using FuEP2/Ex2 may be of use in the treatment of endometrial cancer.

Resveratrol commonly displays hormesis: occurrence and biomedical significance

Resveratrol induces hormetic dose responses in a wide range of biological models, affecting numerous endpoints of biomedical and therapeutic significance. These responses were reported for numerous human tumor cell lines affecting breast, prostate, colon, lung, uterine and leukemia. In such cases, low concentrations of resveratrol enhanced tumor cell proliferation whereas higher concentrations were inhibitory. Similar resveratrol-induced biphasic dose responses were seen with several parasitic diseases, including Leishmaniasis and trichinella. Hormetic effects were also reported in animal models for cardiovascular induced injury, gastric lesions, ischemic stroke, Alzheimer's disease and osteoporosis. In these cases, there was often a protective effect at low doses but an adverse effect at higher doses, exacerbating the disease process/incidence. This analysis indicates that many effects induced by resveratrol are dependent on dose and that opposite effects occur at low and high doses, being indicative of a hormetic dose response. Despite consistent occurrence of hormetic dose responses of resveratrol in a wide range of biomedical models, epidemiologic and clinical trials are needed to assess the nature of its dose-response in humans.

A functional and transcriptomic analysis of NET1 bioactivity in gastric cancer

BACKGROUND

NET1, a RhoA guanine exchange factor, is up-regulated in gastric cancer (GC) tissue and drives the invasive phenotype of this disease. In this study, we aimed to determine the role of NET1 in GC by monitoring the proliferation, motility and invasion of GC cells in which NET1 has been stably knocked down. Additionally, we aimed to determine NET1-dependent transcriptomic events that occur in GC.

METHODS

An in vitro model of stable knockdown of NET1 was achieved in AGS human gastric adenocarcinoma cells via lentiviral mediated transduction of short-hairpin (sh) RNA targeting NET1. Knockdown was assessed using quantitative PCR. Cell proliferation was assessed using an MTS assay and cell migration was assessed using a wound healing scratch assay. Cell invasion was assessed using a transwell matrigel invasion assay. Gene expression profiles were examined using affymetrix oligonucleotide U133A expression arrays. A student's t test was used to determine changes of statistical significance.

RESULTS

GC cells were transduced with NET1 shRNA resulting in a 97% reduction in NET1 mRNA (p < 0.0001). NET1 knockdown significantly reduced the invasion and migration of GC cells by 94% (p < 0.05) and 24% (p < 0.001) respectively, while cell proliferation was not significantly altered following NET1 knockdown. Microarray analysis was performed on non-target and knockdown cell lines, treated with and without 10 μM lysophosphatidic acid (LPA) allowing us to identify NET1-dependent, LPA-dependent and NET1-mediated LPA-induced gene transcription. Differential gene expression was confirmed by quantitative PCR. Shortlisted NET1-dependent genes included STAT1, TSPAN1, TGFBi and CCL5 all of which were downregulatd upon NET1 downregulation. Shortlisted LPA-dependent genes included EGFR and PPARD where EGFR was upregulated and PPARD was downregulated upon LPA stimulation. Shortlisted NET1 and LPA dependent genes included IGFR1 and PIP5K3. These LPA induced genes were downregulated in NET1 knockdown cells.

CONCLUSIONS

NET1 plays an important role in GC cell migration and invasion, key aspects of GC progression. Furthermore, the gene expression profile further elucidates the molecular mechanisms underpinning NET1-mediated aggressive GC cell behaviour.

PPARδ activation acts cooperatively with 3-phosphoinositide-dependent protein kinase-1 to enhance mammary tumorigenesis

Peroxisome proliferator-activated receptorδ (PPARδ) is a transcription factor that is associated with metabolic gene regulation and inflammation. It has been implicated in tumor promotion and in the regulation of 3-phosphoinositide-dependent kinase-1 (PDK1). PDK1 is a key regulator of the AGC protein kinase family, which includes the proto-oncogene AKT/PKB implicated in several malignancies, including breast cancer. To assess the role of PDK1 in mammary tumorigenesis and its interaction with PPARδ, transgenic mice were generated in which PDK1 was expressed in mammary epithelium under the control of the MMTV enhancer/promoter region. Transgene expression increased pT308AKT and pS9GSK3β, but did not alter phosphorylation of mTOR, 4EBP1, ribosomal protein S6 and PKCα. The transgenic mammary gland also expressed higher levels of PPARδ and a gene expression profile resembling wild-type mice maintained on a diet containing the PPARδ agonist, GW501516. Both wild-type and transgenic mice treated with GW501516 exhibited accelerated rates of tumor formation that were more pronounced in transgenic animals. GW501516 treatment was accompanied by a distinct metabolic gene expression and metabolomic signature that was not present in untreated animals. GW501516-treated transgenic mice expressed higher levels of fatty acid and phospholipid metabolites than treated wild-type mice, suggesting the involvement of PDK1 in enhancing PPARδ-driven energy metabolism. These results reveal that PPARδ activation elicits a distinct metabolic and metabolomic profile in tumors that is in part related to PDK1 and AKT signaling.

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.

PGF2α-F-prostanoid receptor signalling via ADAMTS1 modulates epithelial cell invasion and endothelial cell function in endometrial cancer

Background

An increase in cancer cell invasion and microvascular density is associated with a poorer prognosis for patients with endometrial cancer. In endometrial adenocarcinoma F-prostanoid (FP) receptor expression is elevated, along with its ligand prostaglandin (PG)F_2α, where it regulates expression and secretion of a host of growth factors and chemokines involved in tumorigenesis. This study investigates the expression, regulation and role of a disintegrin and metalloproteinase with thrombospondin repeat 1 (ADAMTS1) in endometrial adenocarcinoma cells by PGF_2α via the FP receptor.

Methods

Human endometrium and adenocarcinoma tissues were obtained in accordance with Lothian Research Ethics Committee guidance with informed patient consent. Expression of ADAMTS1 mRNA and protein in tissues was determined by quantitative RT-PCR analysis and immunohistochemistry. Signal transduction pathways regulating ADAMTS1 expression in Ishikawa cells stably expressing the FP receptor to levels seen in endometrial cancer (FPS cells) were determined by quantitative RT-PCR analysis. In vitro invasion and proliferation assays were performed with FPS cells and human umbilical vein endothelial cells (HUVECs) using conditioned medium (CM) from PGF_2α-treated FPS cells from which ADAMTS1 was immunoneutralised and/or recombinant ADAMTS1. The role of endothelial ADAMTS1 in endothelial cell proliferation was confirmed with RNA interference. The data in this study were analysed by T-test or ANOVA.

Results

ADAMTS1 mRNA and protein expression is elevated in endometrial adenocarcinoma tissues compared with normal proliferative phase endometrium and is localised to the glandular and vascular cells. Using FPS cells, we show that PGF2α-FP signalling upregulates ADAMTS1 expression via a calmodulin-NFAT-dependent pathway and this promotes epithelial cell invasion through ECM and inhibits endothelial cell proliferation. Furthermore, we show that CM from FPS cells regulates endothelial cell ADAMTS1 expression in a rapid biphasic manner. Using RNA interference we show that endothelial cell ADAMTS1 also negatively regulates cellular proliferation.

Conclusions

These data demonstrate elevated ADAMTS1 expression in endometrial adenocarcinoma. Furthermore we have highlighted a mechanism whereby FP receptor signalling regulates epithelial cell invasion and endothelial cell function via the PGF_2α-FP receptor mediated induction of ADAMTS1.

F-Prostaglandin receptor regulates endothelial cell function via fibroblast growth factor-2

Background

Prostaglandin (PG) F_2α is a key regulator of endometrial function and exerts its biological action after coupling with its heptahelical G protein-coupled receptor (FP receptor). In endometrial adenocarcinoma the FP receptor expression is elevated. We have shown previously that PGF_2α-FP receptor signalling in endometrial adenocarcinoma cells can upregulate several angiogenic factors including fibroblast growth factor-2 (FGF2). In the present study, we investigated the paracrine effect of conditioned medium produced via PGF_2α-FP receptor signalling in endometrial adenocarcinoma cells stably expressing the FP receptor (Ishikawa FPS cells), on endothelial cell function.

Results

Conditioned medium (CM) was collected from FPS cells after 24 hrs treatment with either vehicle (V CM) or 100 nM PGF_2α (P CM). Treatment of human umbilical vein endothelial cells (HUVECs) with P CM significantly enhanced endothelial cell differentiation (network formation) and proliferation. Using chemical inhibitors of intracellular signalling, we found that P CM-stimulated endothelial cell network formation was mediated by secretion of endothelial PGF_2α and activation of endothelial FP receptors, following FGF2-FGFR1 signalling, phosphorylation of ERK1/2 and induction of COX-2. Whereas, P CM stimulation of endothelial cell proliferation occurred independently of PGF_2α secretion via an FGF2-FGFR1-ERK1/2 dependent mechanism involving activation of the mTOR pathway.

Conclusions

Taken together, we have shown a novel mechanism whereby epithelial prostaglandin F_2α-FP signalling regulates endothelial cell network formation and proliferation. In addition we provide novel in vitro evidence to suggest that prostaglandin F_2α can directly regulate endothelial cell network formation but not endothelial cell proliferation. These findings have relevance for pathologies where the FP receptor is aberrantly expressed, such as endometrial adenocarcinoma, and provide in vitro evidence to suggest that targeting the FP receptor could provide an anti-angiogenic approach to reducing tumour vasculature and growth.

Interleukin-11 in endometrial adenocarcinoma is regulated by prostaglandin F2alpha-F-prostanoid receptor interaction via the calcium-calcineurin-nuclear factor of activated T cells pathway and negatively regulated by the regulator of calcineurin-1

Interleukin-11 (IL-11) up-regulates the proliferative and invasive capacity of many cancers. Coexpression of glycoprotein 130 (GP130) and IL-11 receptor alpha (IL-11Ralpha) is necessary for high-affinity binding of IL-11 to IL-11Ralpha. This study investigated the expression of IL-11 and role of prostaglandin F(2alpha)-F-prostanoid receptor (FP receptor) signaling in the modulation of IL-11 expression in endometrial adenocarcinoma cells. Localization of IL-11, IL-11Ralpha, and GP130 expression was performed by immunohistochemistry. IL-11 and regulator of calcineurin 1 isoform 4 (RCAN1-4) mRNA and protein expression were determined by real-time RT-PCR and/or enzyme-linked immunosorbent assay/Western blot analysis using Ishikawa endometrial adenocarcinoma cells stably expressing the FP receptor (FPS cells) and endometrial adenocarcinoma explants. IL-11 mRNA expression was significantly elevated in endometrial adenocarcinoma samples compared with normal endometrium and increased with tumor grade. IL-11 protein expression localized with FP receptor, IL-11Ralpha, and GP130 in the neoplastic glandular epithelium of endometrial adenocarcinomas. Prostaglandin F(2alpha)-FP receptor signaling significantly elevated the expression of IL-11 mRNA and protein in a Gq-protein kinase C-calcium-calcineurin-nuclear factor of activated T cells-dependent manner in FPS cells. The calcineurin signaling pathway is known to be controlled by the RCAN (RCAN1-4). Indeed, RCAN1-4 expression was significantly elevated in well-differentiated endometrial adenocarcinoma compared with normal endometrium and was found to decrease with tumor grade and negatively regulate IL-11 expression in vitro. This study has highlighted a new mechanism regulating IL-11 expression in endometrial adenocarcinoma cells by the FP receptor via the calcium-calcineurin-nuclear factor of activated T cells pathway.

Peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) acts as regulator of metabolism linked to multiple cellular functions

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors. They function as ligand activated transcription factors. They exist in three isoforms, PPARalpha, PPARbeta (formerly PPARdelta), and PPARgamma. For all PPARs lipids are endogenous ligands, linking them directly to metabolism. PPARs form heterodimers with retinoic X receptors, and, upon ligand binding, modulate gene expression of downstream target genes dependent on the presence of co-repressors or co-activators. This results in cell-type specific complex regulations of proliferation, differentiation and cell survival. Specific synthetic agonists for all PPARs are available. PPARalpha and PPARgamma agonists are already in clinical use for the treatment of hyperlipidemia and type 2 diabetes, respectively. More recently, PPARbeta activation came into focus as an interesting novel approach for the treatment of metabolic syndrome and associated cardiovascular diseases. Although the initial notion was that PPARbeta is expressed ubiquitously, more recently extensive investigations have been performed demonstrating high PPARbeta expression in a variety of tissues, e.g. skin, skeletal muscle, adipose tissue, inflammatory cells, heart, and various types of cancer. In addition, in vitro and in vivo studies using specific PPARbeta agonists, tissue-specific over-expression or knockout mouse models have demonstrated a variety of functions of PPARbeta in adipose tissue, muscle, skin, inflammation, and cancer. We will focus here on functions of PPARbeta in adipose tissue, skeletal muscle, heart, angiogenesis and cancer related to modifications in metabolism and the identified underlying molecular mechanisms.

Prognostic Significance and Clinicopathological Associations of COX-2 SNP in Patients with Nonsmall Cell Lung Cancer

Background. To further improve the screening, diagnosis, and therapy of patients with nonsmall cell lung cancer (NSCLC) additional diagnostic tools are urgently needed. Gene expression of Cyclooxygenase-2 (COX-2) has been linked to prognosis in patients with NSCLC. The role of the COX-2 926G>C Single Nucleotide Polymorphism (SNP) in patients with NSCLC remains unclear. The aim of this study was to investigate the potential of the COX-2 926G>C SNP as a molecular marker in this disease. Methods. COX-2 926G>C SNP was analyzed in surgically resected tumor tissue of 85 patients with NSCLC using a PCR-based RFLP technique. Results. The COX-2 926G>C SNP genotypes were detected with the following frequencies: GG n = 62 (73%), GC n = 20 (23%), CC n = 3 (4%). There were no associations between COX-2 SNP genotype and histology, grading or gender detectable. COX-2 SNP was significantly associated with tumor stage (P = .032) and lymph node status (P = .016, Chi-square test). With a median followup of 85.9 months, the median survival was 59.7 months. There were no associations seen between the COX-2 SNP genotype and patients prognosis. Conclusions. The COX-2 926G>C SNP is detectable at a high frequency in patients with NSCLC. The COX-2 926G>C SNP genotype is not a prognostic molecular marker in this disease. However, patients with the GC or CC genotype seem more susceptible to lymph node metastases and higher tumor stage than patients with the GG genotype. The results suggest COX-2 926G>C SNP as a molecular marker for lymph node involvement in this disease.

Prostaglandin F(2alpha)-F-prostanoid receptor regulates CXCL8 expression in endometrial adenocarcinoma cells via the calcium-calcineurin-NFAT pathway

Pro-inflammatory mediators, like prostaglandin (PG) and chemokines, promote tumourigenesis by enhancing cell proliferation, migration of immune cells and recruitment of blood vessels. Recently we showed elevated expression of the chemokine (C-X-C motif) receptor 2 (CXCR2) in endometrial adenocarcinomas localized to neutrophils and neoplastic epithelial and vascular cells. Furthermore we found that PGF_2α-F-prostanoid (FP) receptor regulates the expression of the CXCR2 ligand CXCL1, to promote neutrophil chemotaxis in endometrial adenocarcinomas. In the present study we identified another CXCR2 ligand, CXCL8 as a target for PGF_2α-FP receptor signalling which enhances epithelial cell proliferation in endometrial adenocarcinoma cells in vitro and in nude mice in vivo. We found that PGF_2α-FP receptor interaction induces CXCL8 expression in endometrial adenocarcinoma cells via the protein kinase C–calcium–calcineurin–NFAT signaling pathway. Promoter analysis revealed that CXCL8 transcriptional activation by PGF_2α signaling is mediated by cooperative interactions between the AP1 and NFAT binding sites. Furthermore, PGF_2α via the FP receptor induced the expression of the regulator of calcineurin 1 isoform 4 (RCAN1-4) via the calcineurin/NFAT pathway in a reciprocal manner to CXCL8. Using an adenovirus to overexpress RCAN1-4, we found that RCAN1-4 is a negative regulator of CXCL8 expression in endometrial adenocarcinoma cells. Taken together our data have elucidated the molecular and cellular mechanism whereby PGF_2α regulates CXCL8 expression via the FP receptor in endometrial adenocarcinomas and have highlighted RCAN1-4 as a negative regulator of CXCL8 expression which may be exploited therapeutically to inhibit CXCL8-mediated tumour development.

Inflammatory pathways in female reproductive health and disease

Inflammation involves alterations to vascular and immune cell function. It is well recognised that many physiological reproductive events such as ovulation, menstruation, implantation and onset of labour display hallmark signs of inflammation. These are orchestrated by specific molecular pathways involving a host of growth factors, cytokines, chemokines and lipid mediators. Resumption of normal reproductive function involves prompt and proper resolution of these inflammatory pathways. Recent literature confirms that resolution of inflammatory pathways involves specific biochemical events that are activated to re-establish homeostasis in the affected tissue. Moreover, initiation and maintenance of inflammatory pathways are the key components of many pathologies of the reproductive tract and elsewhere in the body. The onset of reproductive disorders or disease may be the result of exacerbated activation and maintenance of inflammatory pathways or their dysregulated resolution. This review will address the role of inflammatory events in normal reproductive function and its pathologies.

Nonsteroidal anti-inflammatory drug use and endometrial cancer risk in the NIH-AARP Diet and Health Study

Chronic inflammation may play an etiologic role in endometrial cancer. Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce inflammatory activity by inhibiting the proinflammatory cyclooxygenase enzymes and, therefore, may decrease cancer risk. However, few studies have examined the association between NSAID use and endometrial cancer. We conducted a prospective study among 72,524 women in the NIH-AARP Diet and Health Study. Women completed a questionnaire in 1996-1997 on lifestyle and health-related factors, including type and frequency of NSAID use within the past year, and were followed through 2003 by linkages to cancer registries and vital status databases. During 488,261 person-years of follow-up, there were 732 incident endometrial cancers. NSAID use, compared with nonuse of NSAIDs, was not significantly associated with endometrial cancer risk [relative risk (RR), 0.90; 95% confidence interval (95% CI), 0.74-1.09]. Null associations were also observed by type of NSAID use [aspirin only: RR, 0.88; 95% CI, 0.70-1.11; nonaspirin NSAID (NA-NSAID) only: RR, 1.01; 95% CI, 0.79-1.29; both aspirin and NA-NSAIDs: RR, 0.85; 95% CI, 0.68-1.06]. Generally, results were not statistically significant by frequency of use for aspirin or NA-NSAIDs. Results did not change when women with a history of heart disease, hypertension, or diabetes were excluded to minimize the potential for confounding by indication. Overall, our data do not support an association between aspirin or NA-NSAID use and endometrial cancer risk.

Identification of transcriptional biomarkers induced by SERMS in human endometrial cells using multivariate analysis of DNA microarrays

Functional genomic tools such as DNA microarrays are having a major impact on the drug-discovery process. Potentially, compounds with toxic responses can be identified and removed at a relatively early stage in the drug-development process before tests on animals or humans, solely on the gene expression profiles produced in cell culture. The study examined the expression profiles of primary cultured human endometrial cells treated with 17beta-oestradiol and the SERMs (selective oestrogen receptor modulators) tamoxifen and raloxifene. Primary cultures from three individuals were split into glandular epithelial cells and stromal cell types. Principal components and partial least-squares-discriminate analyses were employed to examine the transcript profile as a whole, identifying genes responsible for patient separation and those that might have an important role in tamoxifen-associated carcinogenesis. Using multivariate data analysis, transcriptional responses were identified in epithelial cells but not in stromal cells for the three SERMs examined. However, it was demonstrated that a major problem associated with using primary cultures derived from human patients is the large transcriptional differences that might exist between the different cultures.

Conditional loss of uterine Pten unfailingly and rapidly induces endometrial cancer in mice

Etiology of endometrial cancer (EMC) is not fully understood. Animal models with rapidly and spontaneously developing EMC will help explore mechanisms of cancer initiation and progression. Pten(+/-) mice are currently being used as a model to study EMC. These females develop atypical endometrial hyperplasia of which approximately 20% progresses to EMC. In addition, tumors develop in other organs, complicating the use of this model to specifically study EMC. Here, we show that conditional deletion of endometrial Pten results in EMC in all female mice as early as age 1 month with myometrial invasion occurring by 3 months. In contrast, conditional deletion of endometrial p53 had no phenotype within this time frame. Whereas mice with endometrial Pten deletion had a life span of approximately 5 months, mice with combined deletion of endometrial Pten and p53 had a shorter life span with an exacerbated disease state. Such rapid development of EMC from homozygous loss of endometrial Pten suggests that this organ is very sensitive to this tumor suppressor gene for tumor development. All lesions at early stages exhibited elevated Cox-2 and phospho-Akt levels, hallmarks of solid tumors. More interestingly, levels of two microRNAs miR-199a(*) and miR-101a that posttranscriptionally inhibit Cox-2 expression were down-regulated in tumors in parallel with Cox-2 up-regulation. This mouse model in which the loxP-Cre system has been used to delete endometrial Pten and/or p53 allows us to study in detail the initiation and progression of EMC. These mouse models have the added advantage because they mimic several features of human EMC.

Peroxisome proliferator-activated receptor beta/delta expression and activation in lung cancer

Peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta) is a ligand-binding inducible transcriptional factor linked to carcinogenesis. Important functions of PPARbeta/delta were demonstrated in series of human epithelial cancers; however, its role in lung cancer remains controversial. We investigated the differential expression level and localization of PPARbeta/delta in tumors and adjacent normal lung tissue, and the effect of PPARbeta/delta activation on lung cancer cell proliferation and apoptosis. PPARbeta/delta was expressed in all studied human non-small cell lung cancers, and strong PPARbeta/delta immunoreactivity was observed in epithelial cells of more than 75% of studied lung tumors. PPARbeta/delta expression was consistently limited to the cancer cells in tumor tissue, while in adjacent normal lung tissue it was limited predominantly to the mononuclear cells. We found that ligand-binding activation of PPARbeta/delta stimulates cell proliferation (an effect that was blocked by a dominant-negative construct of PPARbeta/delta), stimulates anchorage-independent cell growth, and inhibits apoptosis in lung cancer cell lines. Importantly, the activation of PPARbeta/delta induces Akt phosphorylation correlated with up-regulation of PDK1, down-regulation of PTEN, and increased expression of Bcl-xL and COX-2. These findings indicate that PPARbeta/delta exerts proliferative and anti-apoptotic effects via PI3K/Akt1 and COX-2 pathways. In conclusion, PPARbeta/delta is strongly expressed in the majority of lung cancers, and its activation induces proliferative and survival response in non-small cell lung cancer.

Cyclooxygenase-2 in cancer and angiogenesis

Tumor angiogenesis is a process where new blood vessels are formed from preexisting ones, resulting in several pathologies. Solid tumors induce angiogenesis to obtain the required nutrients and oxygen. Otherwise, tumors do not grow beyond 2 to 3 mm in diameter. Cyclooxygenase-2, an inducible enzyme important in inflammation, catalyzes the production of prostanoids from arachidonic acid. Cyclooxygenase-2 plays an important role in several cancer types, including colorectal, gastric, prostate, breast, lung, and endometrial cancer. Besides, cyclooxygenase-2 has been implicated in the progression and angiogenesis of cancers. Cyclooxygenase-2 inhibitors have been used to block angiogenesis and tumor proliferation. In this review, the recent studies related to the role of cyclooxygenase-2 in several cancer types and tumor-induced angiogenesis were compiled.

Prostaglandin E2 and F2alpha activate the FP receptor and up-regulate cyclooxygenase-2 expression via the cyclic AMP response element

In endometrial adenocarcinomas COX-2 and F-series prostanoid (FP) receptor expression and prostanoid biosynthesis (PGE(2) and PGF(2alpha)) are elevated. In the present study, we investigated the effect of PGE(2) and PGF(2alpha) on the expression of COX-2 via the FP receptor in endometrial adenocarcinoma cells stably expressing the FP receptor (FPS cells). Using chemical inhibitors of intracellular signaling pathways, reporter gene assays and quantitative RT-PCR analysis, we show that PGE(2) and PGF(2alpha) can mobilize inositol 1,4,5-trisphosphate, induce ERK1/2 phosphorylation via the phospholipase Cbeta-protein kinase A-epidermal growth factor receptor pathway and induce cyclooxygenase-2 (COX-2) expression via the FP receptor. In addition we show that the PGE(2) or PGF(2alpha)-regulation of COX-2 via the FP receptor is mediated via the cAMP response element (CRE) binding site on the COX-2 promoter. These data indicate that PGE(2) and PGF(2alpha) biosynthesized locally within endometrial adenocarcinomas can regulate tumor cell function in an autocrine/paracrine manner via the FP receptor.