Expression of cyclooxygenase 2 by prostaglandin E(2) in human endometrial adenocarcinoma cell line HEC-1B

Prognostic and Clinical Significance of Cyclooxygenase-2 Overexpression in Endometrial Cancer: A Meta-Analysis

Objective: Cyclooxygenase-2 (COX-2) is a critical enzyme associated with inflammation and tumorigenesis. Although several studies have compared the expression of COX-2 in endometrial cancer tissues and normal tissues, the results have been inconsistent thus far. This study aims to conduct a meta-analysis to elucidate the role of COX-2 in the determination of the risk, prognosis, and clinical features of endometrial cancer. Methods: We retrieved the suitable studies on the association between COX-2 expression and endometrial cancer from PubMed, EMBASE, and Web of Science databases that were published between 1999 and September 31st, 2019. The hazard ratio (HR) and 95% confidence intervals (CIs) were retrieved to assess the relationship between COX-2 expression and the prognosis of endometrial cancer. The odds ratio (OR) and 95% CIs were calculated to evaluate the correlation between COX-2 expression and the risk and clinical features of endometrial cancer. Results: To investigate the association between COX-2 expression and the susceptibility, clinical features, and prognosis of endometrial cancer, we performed a meta-analysis on data from selected studies that collectively involved 273 normal individuals and 1,376 patients with endometrial cancer. Overall, the pooled analysis indicated that COX-2 expression was significantly associated with susceptibility (Caucasians, OR = 3.94, 95% CI = 2.17-7.17, P < 0.05; Asians, OR = 20.51, 95% CI = 8.54-49.26, P < 0.05), cancer stage (OR = 3.01, 95% CI = 1.95-4.67, P < 0.05), myometrial invasion (OR = 1.59, 95% CI = 1.17-2.15, P < 0.05), lymph node metastasis (OR = 1.63, 95% CI = 1.18-2.26, P < 0.05), and prognosis (OR = 2.91, 95% CI = 1.17-4.66, P < 0.05) in endometrial cancer. Conclusions: Our findings suggested that COX-2 overexpression is significantly associated with poor prognosis and advanced clinical features in endometrial cancer. Therefore, COX-2 may function as an effective prognostic biomarker and a potential therapeutic target for endometrial cancer.

A Natural Isoquinoline Alkaloid With Antitumor Activity: Studies of the Biological Activities of Berberine

Coptis, a traditional medicinal plant, has been used widely in the field of traditional Chinese medicine for many years. More recently, the chemical composition and bioactivity of Coptis have been studied worldwide. Berberine is a main component of Rhizoma Coptidis. Modern medicine has confirmed that berberine has pharmacological activities, such as anti-inflammatory, analgesic, antimicrobial, hypolipidemic, and blood pressure-lowering effects. Importantly, the active ingredient of berberine has clear inhibitory effects on various cancers, including colorectal cancer, lung cancer, ovarian cancer, prostate cancer, liver cancer, and cervical cancer. Cancer, ranked as one of the world’s five major incurable diseases by WHO, is a serious threat to the quality of human life. Here, we try to outline how berberine exerts antitumor effects through the regulation of different molecular pathways. In addition, the berberine-mediated regulation of epigenetic mechanisms that may be associated with the prevention of malignant tumors is described. Thus, this review provides a theoretical basis for the biological functions of berberine and its further use in the clinical treatment of cancer.

Antitumor effect of the selective COX-2 inhibitor celecoxib on endometrial adenocarcinoma in vitro and in vivo

The aim of this study was to investigate the antitumor effect of the selective cyclooxygenase-2 (COX-2) inhibitor celecoxib on endometrial adenocarcinoma in mice. Various amounts of celecoxib were added to HEC-1B cells in vitro for different durations. Cell cycle and apoptosis were analyzed using flow cytometry. HEC-1B cytostasis, invasiveness and COX-2 expression were examined by MTT, transwell cabin and western blot assays, respectively. An in vivo human endometrial adenocarcinoma model was established in BALB/c nude mice using HEC-1B cells. For two weeks, the celecoxib groups were treated with celecoxib 2 or 4 mg/day via oral administration and the control group was treated with saline. Tumor volume, growth curves and the inhibition rate (IR) were recorded. COX-2 expression levels and microvessel density (MVD) were investigated using an immunohistochemical technique. In the celecoxib groups, cell proliferation was significantly inhibited in a concentration- and time-dependent manner. The proportion of cells in the G0/G1 phase increased within 24 h after the addition of celecoxib whereas those in the S and G2/M phases decreased with an increasing apoptosis peak (sub-G1) and apoptosis rate. The microporous Matrigel-coated polycarbonate membrane of the Transwell cabin was traversable for the HEC-1B cells. The invasiveness was attenuated when the celecoxib concentration was increased. The tumor growth was also greatly inhibited when the celecoxib concentration was increased. The tumor IRs were 32.4 and 48.6% following treatment with 2 and 4 mg/day celecoxib, respectively. COX-2 was mainly expressed in the cytoplasm of the tumor cells. In the celecoxib groups, the COX-2 expression levels were concentration-dependent. The COX-2 expression level and MVD decreased when the celecoxib concentration was increased. The results of dependability analysis revealed that the COX-2 expression level was positively correlated with MVD (r=0.921; P<0.01). The antitumor effect of celecoxib on endometrial adenocarcinoma in nude mice may be related to the inhibition of COX-2 expression and microangiogenesis.

Role of semen in HIV-1 transmission: inhibitor or facilitator?

Sexual transmission of human immunodeficiency virus type 1 (HIV-1) accounts for 60-90% of new infections, especially in developing countries. During male-to-female transmission, the virus is typically deposited in the vagina as cell-free and cell-associated virions carried by semen. But semen is more than just a carrier for HIV-1. Evidence from in vitro and in vivo studies supports both inhibitory and enhancing effects. Intrinsic antiviral activity mediated by cationic antimicrobial peptides, cytotoxicity, and blockage of HIV-dendritic cell interactions are seminal plasma properties that inhibit HIV-1 infection. On the contrary, neutralization of vaginal acidic pH, enhanced virus-target cell attachment by seminal amyloid fibrils, opsonization by complement fragments, and electrostatic interactions are factors that facilitate HIV-1 infection. The end result, i.e., inhibition or enhancement of HIV mucosal infection, in vivo, likely depends on the summation of all these biological effects. More research is needed, especially in animal models, to dissect the role of these factors and establish their relevance in HIV-1 transmission.

COX-2 and survivin are overexpressed and positively correlated in endometrial carcinoma

OBJECTIVES

To investigate the expressions of survivin and Cyclooxygenase-2 (COX-2), and their possible correlations in the development of endometrial adenocarcinoma (EC). We also looked at their association with classical prognostic factors in EC. To our knowledge, this is the first time survivin expression is investigated in terms of its relation to COX-2 in the developmental pathway of EC.

METHODS

Archived tissue samples of 50 EC, 30 endometrial hyperplasia and 20 proliferative endometrium were selected and immunohistochemically analyzed for survivin and COX-2 expression.

RESULTS

Both survivin and COX-2 were overexpressed in hyperplasia and endometrial adenocarcinoma cases compared to proliferative endometrium, which was statistically significant (p=0.01, p=0.02, respectively). Among EC cases, survivin and COX-2 were strongly positive in 38 (76%) and 30 (60%) patients, respectively. Furthermore, we found survivin and COX-2 to be positively correlated, which was also statistically significant (p=0.0001, r=0.46). Neither survivin nor COX-2 expression was correlated with classical prognostic factors of endometrial carcinoma such as myometrial invasion, grade or lymph node metastasis (p>0.05). Neither COX-2 nor survivin had an impact on overall survival (p>0.05).

CONCLUSIONS

Both survivin and COX-2 are overexpressed, and they seem to be early events in the occurrence of EC. Moreover, protein products of these two genes are positively correlated. COX-2 and survivin might share a common molecular pathway or enhance each other's actions in the developmental pathway of EC. Molecular basis of such a relationship should be further investigated in endometrial carcinogenesis.

Cyclooxygenase-2 (COX-2) Immunostaining Does Not Correlate With the Degree of Vulvar Neoplasia

OBJECTIVE

The cyclooxygenase-2 (COX-2) enzyme is up-regulated in inflammatory and neoplastic conditions. In the last decade, its biological role has been investigated in various pre-invasive and invasive cancers with the hope that it can serve as a target for cancer prevention and treatment.

METHODS

We evaluated the expression of COX-2 in vulvar biopsies to determine its relationship to the degree of dysplasia. COX-2 expression was studied by immunohistochemistry in 62 consecutive vulvar biopsies divided into four diagnostic groups. Group 1 included inflamed vulva (n = 14); group 2, vulvar intraepithelial neoplasia (VIN) I and VIN II (n = 20); group 3, VIN III and carcinoma in situ (n = 18); and group 4, invasive squamous cell carcinoma (n = 10). Representative sections were immunostained using polyclonal anti-COX-2 antibodies at concentration 1:25 without pretreatment. Immunostaining was scored according to the proportion of positive epithelial cells in the vulvar mucosa as 0 (no positive cells), 1(< 5% positive), 2 (6-50% positive), or 3 (> 50% positive).

RESULTS

Mean immunostaining scores were 1.6, 1.4, 0.7, and 1.2 for groups 1, 2, 3, and 4, respectively. Scores were different between the groups (chi(2) = 9.908, P = 0.019) as shown by Cochran-Mantel-Haenszel statistical analysis (modified ridit scores), but did not correlate with age or the degree of dysplasia. The strongest staining for COX-2 was in the inflammatory group.

CONCLUSION

COX-2 staining in inflamed, dysplastic, and malignant vulvar epithelium is variable but, as shown in this study, does not correlate with the degree of vulvar dysplasia or malignancy.

Molecular Mechanism of Neuronal Plasticity: Induction and Maintenance of Long-Term Potentiation in the Hippocampus

Recent studies have demonstrated that activation of enzymes can be observed in living cells in response to stimulation with neurotransmitters, hormones, growth factors, and so forth. Thus, the activation of enzymes was shown to be closely related to the dynamic states of various cell functions. The development of new experimental methodologies has enabled researchers to study the molecular basis of neuronal plasticity in living cells. In 1973, Bliss and his associates identified the phenomena of long-term potentiation (LTP). Since it was thought to be a model for neuronal plasticity such as learning and memory, its molecular mechanism has been extensively investigated. The mechanism was found to involve a signal transduction cascade that includes release of glutamate, activation of the NMDA glutamate receptors, Ca(2+) entry, and activations of Ca(2+)/calmodulin-dependent protein kinases (CaM kinases) II and IV and mitogen-activated protein kinase (MAPK). Consequently, AMPA glutamate receptors were activated by phosphorylation by CaM kinase II, resulting in an increase of Ca(2+) entry into postsynaptic neurons. Furthermore, activation of CaM kinase IV and MAPK increased phosphorylation of CREB (cyclic AMP response element binding protein) and expression of c-Fos by stimulation of gene expression. These results suggest that LTP induction and maintenance would be models of short- and long-term memory, respectively.

Cyclooxygenase-2 expression in the endometrium at the end of 2 years’ continuous combined hormone replacement therapy

OBJECTIVE

To evaluate the change of endometrial histology and the expression of cyclooxygenase-2 (Cox-2) in the endometrium after continuous combined hormone replacement therapy (HRT).

METHODS

Forty-five postmenopausal women were recruited. All participants received 0.625 mg conjugated equine estrogen (CEE) and 2.5 mg medroxyprogesterone (MPA) daily for 2 years. Endometrial biopsy was performed twice, before medication (baseline) and after 2 years of HRT, respectively. Immunohistochemistry was used to detect the presence of Cox-2 expression.

RESULTS

More atrophic and weak secretory features of endometrium were noted after the 2-year HRT. Endometrial hyperplasia and carcinoma were not found and immunohistochemistry results revealed that Cox-2 was not expressed in the endometrium.

CONCLUSION

Cox-2, known to play an important role in the tumorigenesis of cancer, was not stained in endometrium tissue after hormonal induction and more endometrium atrophy was noted after the 2-year HRT. From the results, it is noted that continuous combined HRT may be a relatively safe and appropriate regimen for long-term use in postmenopausal women.

Signal transduction pathways activated by chorionic gonadotropin in the primate endometrial epithelial cells

Successful implantation requires synergism between the developing embryo and the receptive endometrium. In the baboon, infusion of chorionic gonadotropin (CG) modulates both morphology and physiology of the epithelial and stromal cells of the receptive endometrium. This study explored the signal transduction pathways activated by CG in endometrial epithelial cells from baboon (BE) and human (HES). Incubations of BE and HES cells with CG did not significantly alter adenylyl cyclase activity or increase intracellular cAMP when compared with Chinese hamster ovarian cells stably transfected with the full-length human CG/luteinizing hormone (LH) receptor (CHO-LH cells). However, in BE and HES cells, CG induced the phosphorylation of several proteins, among them, extracellular signal-regulated protein kinases 1 and 2 (ERK 1/2). Phosphorylation of ERK 1/2 in uterine epithelial cells was protein kinase A (PKA) independent. This novel signaling pathway is functional because, in response to CG stimulation, prostaglandin E(2) (PGE(2)) was released into the media and increased significantly 2 h following CG stimulation. CG-stimulated PGE(2) synthesis in epithelial cells was inhibited by a specific mitogen-activated protein kinase (MEK 1/2) inhibitor, PD 98059. In conclusion, immediate signal transduction pathways induced by CG in endometrial epithelial cells are cAMP independent and stimulate phosphorylation of ERK 1/2 via a MEK 1/2 pathway, leading to an increase in PGE(2) release as the possible result of cyclooxygenase-2 activation.

Selective cyclooxygenase-2 inhibition: a target in cancer prevention and treatment

A major goal in the area of cancer prevention and treatment is to make rational use of defined molecular targets in order to block carcinogenesis. Studies conducted in experimental animal models for many human cancers, including those of lung, skin, mammary gland, urinary bladder, colon, and pancreas, have demonstrated that carcinogenesis often may be inhibited by the administration of a highly diverse group of biologic and chemical agents. One very promising and well-studied target is cyclooxygenase (COX)-2. Interestingly, a number of cancers appear to overexpress the COX-2 enzyme, which may play several roles in carcinogenesis. Recent clinical studies have demonstrated the effect of COX-2 inhibitors in the treatment of familial adenomatous polyposis, a genetic disorder that increases the risk for developing colorectal cancer. Ongoing clinical trials with COX-2 inhibitors will increase our understanding and may give us profound insights into the general applicability of this new targeted approach for cancer control.

Seminal plasma activates cyclooxygenase-2 and prostaglandin E2 receptor expression and signalling in cervical adenocarcinoma cells

Enhanced cyclooxygenase (COX) expression and prostaglandin E2 (PGE2) synthesis are regarded as promoters of neoplastic cell proliferation and angiogenesis. Expression of COX-2 and synthesis of PGE2 are up-regulated in cervical carcinomas. In sexually active women, growth and invasiveness of neoplastic cervical epithelial cells may be also under the direct influence of PGE2 present in seminal plasma. The aims of this study were to investigate the effect of seminal plasma and PGE2 on the expression of COX-2 and expression and signalling of the PGE2 receptor subtypes (EP1-EP4) in HeLa (cervical adenocarcinoma) cells. Treatment of HeLa cells with seminal plasma or PGE2 resulted in up-regulation of COX-2 expression (P < 0.05). In addition, seminal plasma induced the mRNA expression of EP1, EP2 and EP4 receptors, whilst PGE2 treatment of HeLa cells induced the expression of the EP4 receptor (P < 0.05). This was coincident with a rapid accumulation of adenosine 3',5'-cyclic monophosphate (cAMP) in HeLa cells stimulated with seminal plasma or PGE2, which was greater in seminal plasma stimulated cells compared with PGE2 stimulated cells (P < 0.05). Subsequently, we investigated whether the effect of seminal plasma on cAMP signalling in HeLa cells was mediated via the cAMP-linked EP2/EP4 receptors. Stimulation of HeLa cells with seminal plasma or PGE2 resulted in an augmented cAMP accumulation in cells transfected with the EP2 or EP4 receptor cDNA compared with control transfected cells (P < 0.05). These data suggest that, in sexually active women, seminal plasma may play a role in modulating neoplastic cell function and cervical tumorigenesis.

Effect of misoprostol and indomethacin on cyclooxygenase induction and eicosanoid production in carrageenan-induced air pouch inflammation in rats

Effects of misoprostol, a synthetic prostaglandin E1 (PGE1) analogue, on cyclooxygenase-2 (COX-2) protein level and exudate prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) level were investigated in acute carrageenan-induced air pouch inflammation in rats. Treatment with misoprostol (12.5, 25, and 50 microg/kg) has been started in separated groups, 30 min and 2 days before carrageenan injection and it was given twice a day (total of five doses) by orogastric route. Indomethacin, in doses of 0.5 and 5 mg/kg, and specific COX-2 inhibitor SC-58236, in doses of 5, 10, and 20 mg/kg were given 1 h before carrageenan injection by the orogastric route. Misoprostol increased the levels of PGE2 and COX-2 protein at all doses applied. Despite indomethacin and SC-58236 increased the level of COX-2 protein when they used alone, these drugs partially inhibited misoprostol-induced increase in the level of COX-2 protein. Partial inhibition of misoprostol-induced increase in the level of COX-2 protein by indomethacin or SC-58236 may indicate the modulatory roles of endogenous prostaglandins (PGs, especially, PGE2) on the COX-2 expression.

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

We investigated the regulation of prostaglandin production in normal endometrial stromal cells (ESC) by malignant endometrial epithelial cells. We found that cyclooxygenase (COX)-2 mRNA and protein levels and prostaglandin (PG)E(2) production in ESC were significantly increased by Ishikawa malignant endometrial epithelial cell conditioned medium (MECM). By using transient transfection assays, we found that the -360/-218-bp region of the COX-2 promoter gene was critical for MECM induction of promoter activity. This MECM-responsive region contained a variant nuclear factor (NF)-kappa B site at -222 to -213 that, when mutated, completely abolished COX-2 promoter activation by MECM. Employing electrophoretic mobility shift assays, we further demonstrated that binding of NF-kappa B p65 to this NF-kappa B-binding site is, in part, responsible for the COX-2 promoter activation by MECM. To investigate further the potential effects of MECM on COX-2 mRNA stability, ESC were treated with MECM in the absence or presence of actinomycin D, a general transcription inhibitor. We found that MECM significantly increased COX-2 mRNA stability. Intriguingly, we found that PGE(2) was one of the major factors in MECM, which was responsible for up-regulating COX-2 expression in ESC. ECC-1 and HEC-1A malignant endometrial epithelial cell lines also produced significantly increased quantities of PGE(2). In conclusion, malignant endometrial epithelial cells secrete PGE(2) that induces COX-2 expression in normal endometrial stromal cells in a paracrine fashion through activation of transcription and stabilization of COX-2 mRNA.

Expression of COX-2, Ki-67, cyclin D1, and P21 in endometrial endometrioid carcinomas

COX-2, the isoform of cyclooxygenase inducible by cytokines, mitogens, and growth factors, appears to play an important role in inflammation and carcinogenesis. In the colon, COX-2 overexpression results in cell cycle alterations, and NSAIDs have proven effective in cancer chemoprevention. HNPCC (hereditary nonpolyposis colon cancer) is a clinically defined cancer susceptibility syndrome in which women are also at significantly increased risk for the development of endometrial carcinoma. The purpose of this study was to evaluate expression of COX-2 in benign and malignant endometrium in the context of other cell cycle and proliferation markers, including Ki-67, cyclin D1, and the cyclin-dependent kinase inhibitor, p21. Immunostains with COX-2, Ki-67, cyclin D1, and p21 antibodies were performed on formalin-fixed and paraffin-embedded tissue sections from 40 cases: 10 benign (5 atrophic and 5 proliferative) endometria, 6 hyperplasias (complex without atypia), and 24 endometrioid carcinomas (9 well, 4 moderately, and 11 poorly differentiated). Ki-67 was positive in all proliferative and neoplastic endometria. Cyclin D1 and p21 were both overexpressed in endometrial hyperplasia and endometrioid carcinomas. COX-2 was negative in the nonneoplastic endometrium, stained minimally in the well-differentiated endometrioid carcinomas, and stained most strongly in the moderately and poorly differentiated endometrioid carcinomas. Because cyclin D1 may function as an oncogene, its effects may dominate the usual inhibitory effect of a rising p21. Alternatively, it has been shown that p21 can promote cell cycle function by stabilizing cell cycle complexes. The overexpression of COX-2 in poorly differentiated endometrioid carcinoma and lack of expression in hyperplasia and well-differentiated carcinoma suggests that in this form of cancer, COX-2 may play a role in tumor progression rather than tumor initiation.

The expression of cyclooxygenase-1 and -2 in proliferative endometrium and endometrial adenocarcinoma

BACKGROUND

The activity of cyclooxygenase-2 (COX-2) is increased in inflammation and in several cancer types. We investigated the expression of COX-2, cyclooxygenase-1 (COX-1), nitric oxide synthase-2 (NOS-2) and nitric oxide synthase-3 (NOS-3) in normal proliferative and secretory human endometrium, and in endometrial adenocarcinoma.

METHODS

Human endometrium was collected at hysterectomy. Seven samples were in proliferative and 11 samples in secretory stage. Twelve specimens from endometrial carcinoma were collected, as well. Immunohistochemistry was used to investigate the expression of COX-1, COX-2, NOS-2 and NOS-3.

RESULTS

COX-2 immunostaining was detected in most specimens of normal proliferative glandular epithelium (86%) and of endometrial carcinomas (92%). COX-2 staining was often detected in cancer cells on the border areas of the tumour and on the areas of invasive growth. Staining for COX-2 was seen in proliferative glands usually only in the basal layer of the endometrium. NOS-2 was usually absent or negligible in proliferative endometrial glands and also in the cancer cells of endometrial adenocarcinomas. No staining for either COX-2 or NOS-2 was seen in specimens of secretory glandular epithelium. The expression of the constitutive COX-1 and NOS-3 was negligible or weak in the glandular epithelium of proliferative and secretory endometrium and in endometrial cancer cells.

CONCLUSIONS

The expression of the inducible COX-2 but not of COX-1 is stimulated in the glandular epithelium of proliferative endometrium and in the cancer cells of human endometrial adenocarcinoma, in particular in those in the borders of carcinoma and spreading into lymphatic vessels.

Expression of COX-2 and PGE synthase and synthesis of PGE(2)in endometrial adenocarcinoma: a possible autocrine/paracrine regulation of neoplastic cell function via EP2/EP4 receptors

This study was designed to investigate the possible role of cyclo-oxygenase-2 (COX-2) and prostaglandin E(2)(PGE(2)) in endometrial adenocarcinoma. COX-2 RNA expression was confirmed in various grades of adenocarcinoma by ribonuclease protection assay. COX-2 and microsomal glutathione-dependent prostaglandin E synthase (mPGES) expression and PGE(2)synthesis were localised to the neoplastic epithelial cells and endothelial cells. In order to establish whether PGE(2)has an autocrine/paracrine effect in adenocarcinomas, we investigated the expression of 2 subtypes of PGE(2)receptors, namely EP2 and EP4, by real time quantitative PCR. Expression of EP2 and EP4 receptors was detected in adenocarcinomas from all grades of differentiation and was significantly higher than that detected in normal secretory phase endometrium (P< 0.01). The fold induction of expression in adenocarcinoma compared with normal secretory phase endometrium was 28.0 +/- 7.4 and 52.5 +/- 10.1 for EP2 and EP4 receptors respectively. Immunohistochemistry localised the site of expression of EP4 receptor in neoplastic epithelial cells and in the endothelium of carcinomas of all grades of differentiation. Finally, the functionality of the EP2/EP4 receptors was assessed by investigating cAMP generation following in vitro culture of adenocarcinoma tissue in the presence or absence of 300 nM PGE(2). cAMP production in response to PGE(2)was significantly higher in carcinoma tissue than that detected in normal secretory phase endometrium (3.42 +/- 0.46 vs 1.15 +/- 0.05 respectively; P< 0.001). In conclusion, these data suggest that PGE(2)may regulate neoplastic cell function in an autocrine/paracrine manner via the EP2/EP4 receptors.