The endometrial cancer cell lines Ishikawa and HEC-1A, and the control cell line HIEEC, differ in expression of estrogen biosynthetic and metabolic genes, and in androstenedione and estrone-sulfate metabolism

A 50-gene biomarker identifies estrogen receptor-modulating chemicals in a microarray compendium

High throughput transcriptomics (HTTr) profiling has the potential to rapidly and comprehensively identify molecular targets of environmental chemicals that can be linked to adverse outcomes. We describe here the construction and characterization of a 50-gene expression biomarker designed to identify estrogen receptor (ER) active chemicals in HTTr datasets. Using microarray comparisons, the genes in the biomarker were identified as those that exhibited consistent directional changes when ER was activated (4 ER agonists; 4 ESR1 gene constitutively active mutants) and opposite directional changes when ER was suppressed (4 antagonist treatments; 4 ESR1 knockdown experiments). The biomarker was evaluated as a predictive tool using the Running Fisher algorithm by comparison to annotated gene expression microarray datasets including those evaluating the transcriptional effects of hormones and chemicals in MCF-7 cells. Depending on the reference dataset used, the biomarker had a predictive accuracy for activation of up to 96%. To demonstrate applicability for HTTr data analysis, the biomarker was used to identify ER activators in a set of 15 chemicals that are considered potential bisphenol A (BPA) alternatives examined at up to 10 concentrations in MCF-7 cells and analyzed by full-genome TempO-Seq. Using benchmark dose (BMD) modeling, the biomarker genes stratified the ER potency of BPA alternatives consistent with previous studies. These results demonstrate that the ER biomarker can be used to accurately identify ER activators in transcript profile data derived from MCF-7 cells.

Autophagy-related risk signature based on CDNK2A to facilitate survival prediction of patients with endometrial cancer

BACKGROUND

Autophagy plays an important role in immunity and inflammation. The present study aimed to explore the prognostic significance of autophagy-related genes (ARGs) in endometrial cancer (EC) using bioinformatics.

METHODS

The list of ARGs was obtained from the Human Autophagy Database. The differentially expressed ARGs (DEARGs) between the EC and normal endometrial tissue samples were screened from The Cancer Genome Atlas database. Cox regression analysis was performed on the DEARGs to screen the prognostic ARGs and construct risk signatures for overall survival (OS) and progression-free survival (PFS). The hub ARGs were identified from a protein-protein interaction network, and CDKN2A was obtained from the intersection of prognostic ARGs and hub ARGs. The association of CDKN2A expression with clinical characteristics and immune infiltration were analyzed. Finally, the role of CDKN2A in autophagy was confirmed in EC cell lines.

RESULTS

CDKN2A, PTK6 and DLC1 were used to establish risk signatures for predicting the survival of EC patients. Receiver operating characteristic curve analysis indicated that the risk signatures can accurately predict both OS and PFS. CDKN2A was the only hub prognostic ARG, and showed significant association with the age, survival status, grade, histological type, body mass index and FIGO (i.e. International Federation of Gynecology and Obstetrics) stage (p < 0.05). Furthermore, CDKN2A expression was also correlated with the infiltration of immune cells, indicating that CDKN2A might play a critical role in regulating the immune microenvironment and immune responses in EC. In addition, silencing of CDKN2A gene promoted autophagy in the HEC-1A cell line and upregulated the expression levels of autophagy-related proteins.

CONCLUSIONS

CDKN2A is a prognostic factor and therapeutic target in EC, and is likely associated with the tumor immune landscape and autophagy.

Cytotoxic effect of 13α-estrane derivatives on breast, endometrial and ovarian cancer cell lines

Hormone-dependent cancers such as breast, uterine, and ovarian cancers account for more than 35% of all cancers in women. Worldwide, these cancers occur in more than 2.7 million women/year and account for 22% of cancer-related deaths/year. The generally accepted mechanism for the pathophysiology of estrogen-dependent cancers is estrogen receptor-mediated cell proliferation associated with an increased number of mutations. Therefore, drugs that can interfere with either local estrogen formation or estrogen action via estrogen receptors are needed. Estrane derivatives that have low or minimal estrogenic activity can affect both pathways. In this study, we investigated the effect of 36 different estrane derivatives on the proliferation of eight breast, endometrial, and ovarian cancer cell lines and the corresponding three control cell lines. Estrane derivatives 3 and 4_2Cl showed a stronger effect on the endometrial cancer cell lines KLE and Ishikawa, respectively, compared with the control cell line HIEEC, with IC50 values of 32.6 microM and 17.9 microM, respectively. Estrane derivative 4_2Cl was most active in the ovarian cancer cell line COV362 compared to the control cell line HIO80 with an IC50 value of 3.6 microM. In addition, estrane derivative 2_4I showed a strong antiproliferative effect on endometrial and ovarian cancer cell lines, while the effect on the control cell line was slight or absent. The addition of halogen at carbon 2 and/or 4 in estrane derivatives 1 and 2 increased the selectivity for endometrial cancer cells. Overall, these results suggest that single estrane derivatives are efficient cytotoxic agents for endometrial and ovarian cancer cell lines, and thus potential lead compounds for drug development.

Changes in the expression of cancer- and metastasis-related genes and proteins after metformin treatment under different metabolic conditions in endometrial cancer cells

Research question

Hyperinsulinemia and elevated estrogen levels are known risk factors for endometrial cancer (EC) development and are associated with obesity, type 2 diabetes mellitus (T2DM), insulin resistance, among others. Metformin, an insulin-sensitizing drug, displays anti-tumor effects in cancer patients, including EC, but the mechanism of action is still not completely understood. In the present study, the effects of metformin on gene and protein expression were investigated in pre- and postmenopausal EC in vitro models in order to identify candidates that are potentially involved in the drug's anti-cancer mechanism.

Design

After treating the cells with metformin (0.1 and 1.0 mmol/L), changes in the expression of >160 cancer- and metastasis-related gene transcripts were evaluated with RNA arrays. A total of 19 genes and 7 proteins were selected for a follow-up expression analysis, including further treatment conditions, in order to evaluate the influence of hyperinsulinemia and hyperglycemia on metformin-induced effects.

Results

Changes in the expression of BCL2L11, CDH1, CDKN1A, COL1A1, PTEN, MMP9 and TIMP2 were analyzed on gene and protein level. The consequences resulting from the detected expression changes as well as the influence of varying environmental influences are discussed in detail. With the presented data, we contribute to a better understanding of the direct anti-cancer activity of metformin as well as its underlying mechanism of action in EC cells.

Conclusions

Although further research will be necessary to confirm the data, the influence of different environmental settings on metformin-induced effects could be highlighted with the presented data. Additionally, gene and protein regulation were not similar in the pre- and postmenopausal in vitro models.

Androgens in endometrial carcinoma: the killer or helper?

PURPOSE

The aim of this review is to discuss the role of androgens in the progression of endometrial carcinoma (EC) with particular focus on the different kinds of androgenic hormones, androgen receptor (AR) and intracrine androgen metabolism.

METHODS

A comprehensive literature search within PubMed was performed. Selected publications related to androgens and EC were reviewed.

RESULTS

There are different kinds of androgenic hormones, and different kinds of androgens may have different effects. Elevated androgens (especially testosterone) have been associated with an increased EC risk in postmenopausal women. 5α-reductases (5α-Reds) and 17β-hydroxysteroid dehydrogenase type 2 (17βHSD2) pathway may inhibit the progression of EC mediated by dihydrotestosterone (DHT), but aromatases stimulate further progression of EC. The most of studies accessing the prognostic value of AR have found that AR expression may be a favorable prognostic indicator.

CONCLUSION

Androgens may have both oncogenic and tumor suppressive roles. Androgen-specific biases in metabolism and the expression of AR may contribute to the different prognosis of patients with EC.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

Integration of androgen hormones in endometrial cancer biology

Endometrial cancer (EC) is a gynecological pathology that affects the uterine inner lining. In recent years, genomic studies revealed continually evolving mutational landscapes of endometrial tumors that hold great potential for tailoring therapeutic strategies. This review aims to broaden our knowledge of EC biology by focusing on the role of androgen hormones. First, we discuss epidemiological evidence implicating androgens with EC pathogenesis and cover their biosynthesis and metabolism to bioactive 11-oxyandrogens. Next, we explore the endometrial tumor tissue and the altered microbiota as alternative sources of androgens and their 11-oxymetabolites in EC patients. Finally, we discuss the biological significance of androgens' genomic and nongenomic signaling as part of a medley of pathways ultimately deciding the fate of cells.

Estradiol mediates the interaction of LINC01541 and miR-429 to promote angiogenesis of G1/G2 endometrioid adenocarcinoma in-vitro: A pilot study

Background

Endometrioid adenocarcinoma (EAC) is the most common subtype of endometrial cancer (EC) and is an estrogen-related cancer. In this study, we sought to investigate the expressions and mechanism of action of 17β-estradiol (E2) and long noncoding RNA (lncRNA) LINC01541 in G1/G2 EAC samples.

Methods

The expressions of estrogen receptor β (ESR2), LINC01541, miR-200s, and VEGFA were evaluated using real-time PCR in human EAC tissues (n = 8) and adjacent normal tissues (n = 8). Two EC cell lines (Ishikawa and RL95-2) were selected for validation in vitro. Bioinformatics analyses and luciferase reporter analyses were performed to verify potential binding sites. qRT-PCR, Western blot, and CCK-8 were used to identify the regulatory mechanisms of related genes in cell biological behavior.

Results

Compared with adjacent normal tissues, LINC01541 and miR-200s family (except miR-200c) were highly expressed in EAC tissues (n=8), while ESR2 and VEGFA were lowly expressed in EAC tissues (* P &lt; 0.05; ** P &lt; 0.01). In vitro: E2 inhibited the expression of LINC01541 and miR-429 in both cell lines, and estrogen antagonist (PHTPP) could reverse this effect, in addition, PHTPP could promote the proliferation of these two cancer cells, cell transfection LINC01541 also had this effect after overexpression of plasmid and miR-429 mimic. E2 promotes the expression of VEGFA in both cell lines, and PHTPP can also reverse this effect. LINC01541 interacts with miR-429 to promote the expression of each other, and both inhibit the synthesis of VEGFA in EAC cells after overexpression. Through the double validation of bioinformatics analysis and dual fluorescein reporter gene, it was confirmed that miR-429 targets the regulation of VEGFA expression (* P &lt; 0.05; ** P &lt; 0.01).

Conclusion

E2 promotes the synthesis of VEGFA by altering the expression levels of LINC01541 and miR-429 in EAC, thereby affecting the angiogenesis process of EAC. Also, E2-mediated LINC01541/miR-429 expression may affect cell migration in EAC. In addition, we identified a reciprocal promotion between LINC01541 and miR-429.

Identifying Environmental Endocrine Disruptors Associated With the Age at Menarche by Integrating a Transcriptome-Wide Association Study With Chemical-Gene-Interaction Analysis

Menarche is the first occurrence of menstrual bleeding and one of the most important events of female puberty. Alarmingly, over the last several decades, the mean age at menarche (AAM) has decreased. Environmental endocrine disruptors (EEDs) are chemicals that may interfere with the endocrine system, resulting in adverse developmental, immunological, neurological, and reproductive effects in humans. Thus, the effects of EEDs on fertility and reproduction are growing concerns in modern societies. In this study, we aimed to determine the influence of genetic and environmental factors on AAM. We used data from an AAM genome-wide association study of 329,345 women to conduct a transcriptome-wide association study (TWAS) with FUSION software. As references, we determined the gene-expression levels in the hypothalamus, pituitary gland, ovaries, uterus, and whole blood. We performed Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses using the significantly dysregulated genes identified by the TWAS. Using the STRING database, we also generated a protein-protein-interaction network to analyze common AAM-specific genes identified by the TWAS with different tissues. We performed chemical-related gene set enrichment analysis (CGSEA) and identified significant TWAS genes to uncover relationships between different chemicals and AAM. The TWAS identified 9,848 genes; among these, 1580 genes were significant (P < 0.05), and 11 genes were significant among the hypothalamus, pituitary, ovary, uterus, and whole blood. CGSEA identified 1,634 chemicals, including 120 chemicals significantly correlated with AAM. In summary, we performed a TWAS (for genetic factors) and CGSEA (for environmental factors) focusing on AAM and identified several AAM-associated genes and EEDs. The results of this study expand our understanding of genetic and environmental factors related to the onset of female puberty.

TET3- and OGT-Dependent Expression of Genes Involved in Epithelial-Mesenchymal Transition in Endometrial Cancer

TET3 is a member of the TET (ten-eleven translocation) proteins family that catalyzes the conversion of the 5-methylcytosine into 5-hydroxymethylcytosine. TET proteins can also affect chromatin modifications and gene expression independently of their enzymatic activity via interactions with other proteins. O-GlcNAc transferase (OGT), the enzyme responsible for modification of proteins via binding of N-acetylglucosamine residues, is one of the proteins whose action may be dependent on TET3. Here, we demonstrated that in endometrial cancer cells both TET3 and OGT affected the expression of genes involved in epithelial to mesenchymal transition (EMT), i.e., FOXC1, TWIST1, and ZEB1. OGT overexpression was caused by an increase in TWIST1 and ZEB1 levels in HEC-1A and Ishikawa cells, which was associated with increased O-GlcNAcylation of histone H2B and trimethylation of H3K4. The TET3 had the opposite effect on gene expressions and histone modifications. OGT and TET3 differently affected FOXC1 expression and the migratory potential of HEC-1A and Ishikawa cells. Analysis of gene expressions in cancer tissue samples from endometrial cancer patients confirmed the association between OGT or TET3 and EMT genes. Our results contribute to the knowledge of the role of the TET3/OGT relationship in the complex mechanism supporting endometrial cancer progression.

In the Model Cell Lines of Moderately and Poorly Differentiated Endometrial Carcinoma, Estrogens Can Be Formed via the Sulfatase Pathway

Endometrial cancer (EC) is the most common gynecological malignancy in resource-abundant countries. The majority of EC cases are estrogen dependent but the mechanisms of estrogen biosynthesis and oxidative metabolism and estrogen action are not completely understood. Here, we evaluated formation of estrogens in models of moderately and poorly differentiated EC: RL95-2 and KLE cells, respectively. Results revealed high expression of estrone-sulfate (E1-S) transporters (SLCO1A2, SLCO1B3, SLCO1C1, SLCO3A1, SLC10A6, SLC22A9), and increased E1-S uptake in KLE vs RL95-2 cells. In RL95-2 cells, higher levels of sulfatase and better metabolism of E1-S to E1 were confirmed compared to KLE cells. In KLE cells, disturbed balance in expression of HSD17B genes led to enhanced activation of E1 to E2, compared to RL95-2 cells. Additionally, increased CYP1B1 expression and down-regulation of genes encoding phase II metabolic enzymes: COMT, NQO1, NQO2, and GSTP1 suggested decreased detoxification of carcinogenic metabolites in KLE cells. Results indicate that in model cell lines of moderately and poorly differentiated EC, estrogens can be formed via the sulfatase pathway.

Altered Profile of E1-S Transporters in Endometrial Cancer: Lower Protein Levels of ABCG2 and OSTβ and Up-Regulation of SLCO1B3 Expression

Endometrial cancer (EC) is associated with increased estrogen actions. Locally, estrogens can be formed from estrone-sulphate (E1-S) after cellular uptake by organic anion-transporting polypeptides (OATP) or organic anion transporters (OAT). Efflux of E1-S is enabled by ATP Binding Cassette transporters (ABC) and organic solute transporter (OST)αβ. Currently, 19 E1-S transporters are known but their roles in EC are not yet understood. Here, we analysed levels of E1-S transporters in Ishikawa (premenopausal EC), HEC-1-A (postmenopausal EC), HIEEC (control) cell lines, in EC tissue, examined metabolism of steroid precursor E1-S, studied effects of OATPs' inhibition and gene-silencing on E1-S uptake, and assessed associations between transporters and histopathological data. Results revealed enhanced E1-S metabolism in HEC-1-A versus Ishikawa which could be explained by higher levels of OATPs in HEC-1-A versus Ishikawa, especially 6.3-fold up-regulation of OATP1B3 (SLCO1B3), as also confirmed by immunocytochemical staining and gene silencing studies, lower ABCG2 expression and higher levels of sulfatase (STS). In EC versus adjacent control tissue the highest differences were seen for ABCG2 and SLC51B (OSTβ) which were 3.0-fold and 2.1-fold down-regulated, respectively. Immunohistochemistry confirmed lower levels of these two transporters in EC versus adjacent control tissue. Further analysis of histopathological data indicated that SLCO1B3 might be important for uptake of E1-S in tumours without lymphovascular invasion where it was 15.6-fold up-regulated as compared to adjacent control tissue. Our results clearly indicate the importance of E1-S transporters in EC pathophysiology and provide a base for further studies towards development of targeted treatment.

Changes in protein expression due to metformin treatment and hyperinsulinemia in a human endometrial cancer cell line

The incidence of endometrial cancer (EC) has increased over the past years and mainly affects women above the age of 45 years. Metabolic diseases such as obesity and type II diabetes mellitus as well as associated conditions like polycystic ovary syndrome (PCOS), insulin resistance and hyperinsulinemia lead to elevated levels of circulating estrogens. Increased estrogen concentrations, in turn, further trigger the proliferation of endometrial cells and thus promote EC development and progression, especially in the absence of progesterone as seen in postmenopausal women. Elevated blood glucose levels in diabetic patients further contribute to the risk of EC development. Metformin is an insulin-sensitizing biguanide drug, commonly used in the treatment of type II diabetes mellitus, especially in obese patients. Besides its effects on glucose metabolism, metformin displayed anti-cancer effects in various cancer types, including EC. Direct anti-cancer effects of metformin target signaling pathways that are involved in cellular growth and proliferation, e.g. the AKT/PKB/mTOR pathway. Further proteins and pathways have been suggested as potential targets, but the underlying mechanism of action of metformin's anti-cancer activity is still not completely understood. In the present study, the effects of metformin on protein expression were investigated in the human EC cell line HEC-1A using an affinity proteomic approach. Cells were treated with 0.5 mmol/L metformin over a period of 7 days and changes in the expression pattern of 1,300 different proteins were compared to the expression in untreated control cells as well as insulin-treated cells. Insulin treatment (100 ng/mL) was incorporated into the study in order to implement a model for insulin resistance and associated hyperinsulinemia, conditions that are often observed in obese and diabetic patients. Furthermore, the culture medium was supplemented with 10 nmol/L ß-estradiol (E2) during treatments to mimic increased estrogen levels, a common risk factor for EC development. Based on the most prominent and significant changes in expression, a set of 80 proteins was selected and subjected to a more detailed analysis. The data revealed that metformin and insulin targeted similar pathways in the present study and mostly acted on proteins related to proliferation, migration and tumor immune response. These pathways may be affected in a tumor-promoting as well as a tumor-suppressing way by either metformin treatment or insulin supplementation. The consequences for the cells resulting from the detected expression changes were discussed in detail for several proteins. The presented data helps identify potential targets affected by metformin treatment in EC and allows for a better understanding of the mechanism of action of the biguanide drug's anti-cancer activity. However, further investigations are necessary to confirm the observations and conclusions drawn from the presented data after metformin administration, especially for proteins that were regulated in a favorable way, i.e. AKT3, CCND2, CD63, CD81, GFAP, IL5, IL17A, IRF4, PI3, and VTCN1. Further proteins might be of interest, where metformin counteracted unfavorable effects that have been induced by hyperinsulinemia.

Gynaecological cancers and their cell lines

Cell lines are widely used for various research purposes including cancer and drug research. Recently, there have been studies that pointed to discrepancies in the literature and usage of cell lines. That is why we have prepared a comprehensive overview of the most common gynaecological cancer cell lines, their literature, a list of currently available cell lines, and new findings compared with the original studies. A literature review was conducted via MEDLINE, PubMed and ScienceDirect for reviews in the last 5 years to identify research and other studies related to gynaecological cancer cell lines. We present an overview of the current literature with reference to the original studies and pointed to certain inconsistencies in the literature. The adherence to culturing rulesets and the international guidelines helps in minimizing replication failure between institutions. Evidence from the latest research suggests that despite certain drawbacks, variations of cancer cell lines can also be useful in regard to a more diverse genomic landscape.

AKR1C3 Is Associated with Better Survival of Patients with Endometrial Carcinomas

The aldo-keto reductase (AKR) superfamily is gaining attention in cancer research. AKRs are involved in important biochemical processes and have crucial roles in carcinogenesis and chemoresistance. The enzyme AKR1C3 has many functions, which include production of prostaglandins, androgens and estrogens, and metabolism of different chemotherapeutics; AKR1C3 is thus implicated in the pathophysiology of different cancers. Endometrial and ovarian cancers represent the majority of gynecological malignancies in developed countries. Personalized treatments for these cancers depend on identification of prognostic and predictive biomarkers that allow stratification of patients. In this study, we evaluated the immunohistochemical (IHC) staining of AKR1C3 in 123 paraffin-embedded samples of endometrial cancer and 99 samples of ovarian cancer, and examined possible correlations between expression of AKR1C3 and other clinicopathological data. The IHC expression of AKR1C3 was higher in endometrial cancer compared to ovarian cancer. In endometrioid endometrial carcinoma, high AKR1C3 IHC expression correlated with better overall survival (hazard ratio, 0.19; 95% confidence interval, 0.06−0.65, p = 0.008) and with disease-free survival (hazard ratio, 0.328; 95% confidence interval, 0.12–0.88, p = 0.027). In patients with ovarian cancer, there was no correlation between AKR1C3 IHC expression and overall and disease-free survival or response to chemotherapy. These results demonstrate that AKR1C3 is a potential prognostic biomarker for endometrioid endometrial cancer.

Novel 3D embryo implantation model within macroporous alginate scaffolds

Background

Implantation failure remains an unsolved obstacle in reproductive medicine. Previous studies have indicated that estrogen responsiveness, specifically by estrogen receptor alpha (ERα), is crucial for proper implantation. There is an utmost need for a reliable in vitro model that mimics the events in the uterine wall during the implantation process for studying the regulatory mechanisms governing the process. The current two-dimensional and hydrogel-based in vitro models provide only short-term endometrial cell culture with partial functionality.

Results

Endometrial biopsies showed an increase in E-cadherin expression on the typical window of implantation of fertile women, compared to negligible expression in recurrent implantation failure (RIF) patients. These clinical results indicated E-cadherin as a marker for receptivity. Three-dimensional (3D) macroporous alginate scaffolds were the base for epithelial endometrial cell-seeding and long-term culture under hormone treatment that mimicked a typical menstrual cycle. The RL95–2 epithelial cell culture in macroporous scaffolds was viable for 3 weeks and showed increased E-cadherin levels in response to estrogen. Human choriocarcinoma (JAR) spheroids were used as embryo models, seeded onto cell constructs and successfully adhered to the RL95–2 cell culture. Moreover, a second model of HEC-1A with low ERα levels, showed lower E-cadherin expression and no JAR attachment. E-cadherin expression and JAR attachment were recovered in HEC-1A cells that were transfected with ERα plasmid.

Conclusions

We present a novel model that enables culturing endometrial cells on a 3D matrix for 3 weeks under hormonal treatment. It confirmed the importance of ERα function and E-cadherin for proper implantation. This platform may serve to elucidate the regulatory mechanisms controlling the implantation process, and for screening and evaluating potential novel therapeutic strategies for RIF.

General toxicity assessment of the novel aldose reductase inhibitor cemtirestat

Cemtirestat, 3-mercapto-5H-[1,2,4]-triazino[5,6-b] indole-5-acetic acid was recently designed and patented as a highly selective and efficient aldose reductase inhibitor endowed with antioxidant activity. The aim of the present study was to assess the general toxicity of cemtirestat using in silico predictions, in vitro and in vivo assays. ProTox-II toxicity prediction software gave 17 "Inactive" outputs, a mild hepatotoxicity score (0.52 probability) along with a predicted LD50 of 1000 mg/kg. Five different cell lines were used including the immortalized mouse microglia BV-2, the primary human fibroblasts VH10, the insulinoma pancreatic β-cells INS-1E, the human colon cancer cells HCT116 and the human immortalized epithelial endometrial cell lines HIEEC. In contrast to the clinically used epalrestat, cemtirestat showed remarkably low cytotoxicity in several different cell culture viability tests such as MTT proliferation assay, neutral red uptake, BrdU incorporation, WST-1 proliferation assay and propidium iodide staining followed by flow cytometry. In a yeast spotting assay, the presence of cemtirestat in incubation of Saccaromyces cerevisiae at concentrations as high as 1000 μM did not affect cell growth rate significantly. In the 120-day repeated oral toxicity study in male Wistar rats with daily cemtirestat dose of 6.4 mg/kg, no significant behavioral alterations or toxicological manifestations were observed in clinical and pathological examinations or in hematological parameters. In summary, these results suggest that cemtirestat is a safe drug that can proceed beyond preclinical studies.

Endometrial cancer and its cell lines

Endometrial cancer is one of the most common gynaecological malignancies worldwide. One type of research in this field is the growing of cell lines (CLs) and cultures, which can be used to explore the biological mechanisms of cancer. The purpose of this review is to offer an overview of the current literature and highlight the importance of correct CL studies. We carried out a literature analysis of more than 60 articles from the Pubmed, Medline databases that were almost exclusively published in indexed journals in the last 10 years as well as the primary originating scientific studies of specific CLs. We then summarized the newest findings and recommendations. Cell lines are becoming widely used as in vitro tumour models. Recent work has shown inconsistencies in nomenclature and culturing of CLs. Their genomic evolution leads to a high degree of variation across CL strains therefore it is of the utmost importance to recognize the variability within laboratory cancer models. Laboratories must adapt, incorporate additional characterisation techniques and view this situation as an opportunity to improve the reproducibility of pre-clinical cancer research. The authors offer a comprehensive literature review about endometrial cancer CLs, a review of the current literature and advice on culturing CLs.

AKR1C3 (type 5 17β-hydroxysteroid dehydrogenase/prostaglandin F synthase): Roles in malignancy and endocrine disorders

Aldo-Keto-Reductase 1C3 (type 5 17β-hydroxysteroid dehydrogenase (HSD)/prostaglandin (PG) F_2α synthase) is the only 17β-HSD that is not a short-chain dehydrogenase/reductase. By acting as a 17-ketosteroid reductase, AKR1C3 produces potent androgens in peripheral tissues which activate the androgen receptor (AR) or act as substrates for aromatase. AKR1C3 is implicated in the production of androgens in castration-resistant prostate cancer (CRPC) and polycystic ovarian syndrome; and is implicated in the production of aromatase substrates in breast cancer. By acting as an 11-ketoprostaglandin reductase, AKR1C3 generates 11β-PGF_2α to activate the FP receptor and deprives peroxisome proliferator activator receptorγ of its putative PGJ₂ ligands. These growth stimulatory signals implicate AKR1C3 in non-hormonal dependent malignancies e.g. acute myeloid leukemia (AML). AKR1C3 moonlights by acting as a co-activator of the AR and stabilizes ubiquitin ligases. AKR1C3 inhibitors have been used clinically for CRPC and AML and can be used to probe its pluripotency.

Role of hydroxysteroid (17beta) dehydrogenase type 1 in reproductive tissues and hormone-dependent diseases

Abnormal synthesis and metabolism of sex steroids is involved in the pathogenesis of various human diseases, such as endometriosis and cancers arising from the breast and uterus. Steroid biosynthesis is a multistep enzymatic process proceeding from cholesterol to highly active sex steroids via different intermediates. Human Hydroxysteroid (17beta) dehydrogenase 1 (HSD17B1) enzyme shows a high capacity to produce the highly active estrogen, estradiol, from a precursor hormone, estrone. However, the enzyme may also play a role in other steps of the steroid biosynthesis pathway. In this article, we have reviewed the literature on HSD17B1, and summarize the role of the enzyme in hormone-dependent diseases in women as evidenced by preclinical studies.

Modeling Endometrial Cancer: Past, Present, and Future

Endometrial cancer is the most common type of cancer of the female reproductive tract. Although prognosis is generally good for patients with low-grade and early-stage diseases, the outcomes for high-grade and metastatic/recurrent cases remain poor, since traditional chemotherapy regimens based on platinum and taxanes have limited effects. No targeted agents have been approved so far, although several new drugs have been tested without striking results in clinical trials. Over the last decades, many efforts have been made towards the establishment and development of preclinical models, aiming at recapitulating the structural and molecular determinants of the disease. Here, we present an overview of the most commonly used in vitro and in vivo models and discuss their peculiar features, describing their main applications and the value in the advancement of both fundamental and translational endometrial cancer research.

Estrogen Receptor (ER) Subtype Selectivity Identifies 8-Prenylapigenin as an ERβ Agonist from Glycyrrhiza inflata and Highlights the Importance of Chemical and Biological Authentication

Postmenopausal women are increasingly using botanicals for menopausal symptom relief due to the increased breast cancer risk associated with traditional estrogen therapy. The deleterious effects of estrogens are associated with estrogen receptor (ER)α-dependent proliferation, while ERβ activation could enhance safety by opposing ERα effects. Three medicinal licorice species, Glycyrrhiza glabra ( G. glabra), G. uralensis, and G. inflata, were studied for their differential estrogenic efficacy. The data showed higher estrogenic potency for G. inflata in an alkaline phosphatase induction assay in Ishikawa cells (ERα) and an estrogen responsive element (ERE)-luciferase assay in MDA-MB-231/β41 breast cancer cells (ERβ). Bioassay-guided fractionation of G. inflata led to the isolation of 8-prenylapigenin (3). Surprisingly, a commercial batch of 3 was devoid of estrogenic activity. Quality control by MS and qNMR revealed an incorrect compound, 4'- O-methylbroussochalcone B (10), illustrating the importance of both structural and purity verification prior to any biological investigations. Authentic and pure 3 displayed 14-fold preferential ERβ agonist activity. Quantitative analyses revealed that 3 was 33 times more concentrated in G. inflata compared to the other medicinal licorice extracts. These data suggest that standardization of G. inflata to 3 might enhance the safety and efficacy of G. inflata supplements used for postmenopausal women's health.

Prostaglandin receptor EP3 regulates cell proliferation and migration with impact on survival of endometrial cancer patients

Background

Prostaglandin E2 (PGE2) receptor 3 (EP3) regulates tumor cell proliferation, migration, and invasion in numerous cancers. The role of EP3 as a prognostic biomarker in endometrial cancer remains unclear. The primary aim of this study was to analyze the prognostic significance of EP3 expression in endometrial cancer.

Methods

We analyzed the EP3 expression of 140 endometrial carcinoma patients by immunohistochemistry. RL95-2 endometrial cancer cell line was chosen from four endometrial cancer cell lines (RL95-2, Ishikawa, HEC-1-A, and HEC-1-B) according to EP3 expression level. Treated with PGE2 and EP3 antagonist, RL95-2 cells were investigated by MTT, BrdU, and wound healing assay for functional assessment of EP3.

Results

EP3 staining differed significantly according to WHO tumor grading in both whole cohort (p = 0.01) and the subgroup of endometrioid carcinoma (p = 0.01). Patients with high EP3 expression in their respective tumors had impaired progression-free survival as well as overall survival in both cohorts above. EP3 expression in the overall cohort was identified as an independent prognostic marker for progression-free survival (HR 1.014, 95%CI 1.003-1.024, p = 0.01) when adjusted for age, stage, grading, and recurrence. Treatment with EP3 antagonists induced upregulation of estrogen receptor β and decreased activity of Ras and led to attenuated proliferation and migration of RL95-2 cells.

Conclusions

EP3 seems to play a crucial role in endometrial cancer progression. In the context of limited systemic treatment options for endometrial cancer, this explorative analysis identifies EP3 as a potential target for diagnostic workup and therapy.

Prostaglandin E2 receptor EP1 in healthy and diseased human endometrium

Prostaglandin E2 (PGE2) is well described to be associated with both endometrial functions and disorders. The primary aim of this study was to explore the underlying mechanisms that affect the growth and function of endometrial epithelium and stroma by assessing the staining intensity of PGE2 receptors (EP) in healthy endometrium across the menstrual cycle and in pathological endometrium, such as ovarian endometriosis and endometrial cancer. We retrospectively analyzed the EPs staining intensity in human nonpregnant endometrium throughout the menstrual cycle by immunohistochemistry and further focused on EP1 (n = 42). The variation of EP1 was compared among healthy endometrium, ovarian endometriosis (n = 14), and endometrial cancer (n = 140) crosswise. EP1 presented cyclical changes with increased intensity in both epithelium and stroma during the proliferative phase. EP1 staining in the epithelium was increased in endometriotic tissue compared to healthy endometrium and tumor tissue, while in the stroma, the staining in the tumor was lower than that in both normal tissue and endometriosis. No significant differences in EP1 intensity were detected for histological, stage, grading, metastatic and recurrent subtypes in endometrial cancer. EP1 was also correlated with neither progression-free survival nor overall survival of patients with cancer. EP1 staining in progesterone receptor B (PRB)-positive tumor was stronger compared to PRB-negative tumor. EP1 may play a role in human endometrial physiology and pathology. Further studies on the effect of EP1 on human endometrium are needed.

STAR and AKR1B10 are down-regulated in high-grade endometrial cancer

Endometrial cancer is the most frequent gynecological malignancy in the developed world. The majority of cases are estrogen dependent, and are associated with diminished protective effects of progesterone. Endometrial cancer is also related to enhanced inflammation and decreased differentiation. In our previous studies, we examined the expression of genes involved in estrogen and progesterone actions in inflammation and tumor differentiation, in tissue samples from endometrial cancer and adjacent control endometrium. The aims of the current study were to examine correlations between gene expression and several demographic characteristics, and to evaluate changes in gene expression with regard to histopathological and clinical characteristics of 51 patients. We studied correlations and differences in expression of 38 genes involved in five pathophysiological processes: (i) estrogen-stimulated proliferation; (ii) estrogen-dependent carcinogenesis; (iii) diminished biosynthesis of progesterone: (iv) enhanced formation of progesterone metabolites; and (v) increased inflammation and decreased differentiation. Spearman correlation coefficient analysis shows that expression of PAQR7 correlates with age, expression of SRD5A1, AKR1B1 and AKR1B10 correlate with body mass, while expression of SRD5A1 and AKR1B10 correlate with body mass index. When patients with endometrial cancer were stratified based on menopausal status, histological grade, myometrial invasion, lymphovascular invasion, and FIGO stage, Mann-Whitney U tests revealed significantly decreased expression of STAR (4.4-fold; adjusted p=0.009) and AKR1B10 (9-fold; adjusted p=0.003) in high grade versus low grade tumors. Lower levels of STAR might lead to decreased de-novo steroid hormone synthesis and tumor differentiation, and lower levels of AKR1B10 to diminished elimination of toxic electrophilic carbonyl compounds in high-grade endometrial cancer. These data thus reveal the potential of STAR and AKR1B10 as prognostic biomarkers, which calls for further validation at the protein level.

The Significance of the Sulfatase Pathway for Local Estrogen Formation in Endometrial Cancer

Endometrial cancer (EC) is the most common estrogen-dependent gynecological malignancy in the developed World. To investigate the local formation of estradiol (E2), we first measured the concentrations of the steroid precursor androstenedione (A-dione) and the most potent estrogen, E2, and we evaluated the metabolism of A-dione, estrone-sulfate (E1-S), and estrone (E1) in cancerous and adjacent control endometrium. Furthermore, we studied expression of the key genes for estradiol formation via the aromatase and sulfatase pathways. A-dione and E2 were detected in cancerous and adjacent control endometrium. In cancerous endometrium, A-dione was metabolized to testosterone, and no E2 was formed. Both, E1-S and E1 were metabolized to E2, with increased levels of E2 seen in cancerous tissue. There was no significant difference in expression of the key genes of the aromatase (CYP19A1) and the sulfatase (STS, HSD17B1, HSD17B2) pathways in cancerous endometrium compared to adjacent control tissue. The mRNA levels of CYP19A1 and HSD17B1 were low, and HSD17B14, which promotes inactivation of E2, was significantly down-regulated in cancerous endometrium, especially in patients with lymphovascular invasion. At the protein level, there were no differences in the levels of STS and HSD17B2 between cancerous and adjacent control tissue by Western blotting, and immunohistochemistry revealed intense staining for STS and HSD17B2, and weak staining for SULT1E1 and HSD17B1 in cancerous tissue. Our data demonstrate that in cancerous endometrium, E2 is formed from E1-S via the sulfatase pathway, and not from A-dione via the aromatase pathway.

The Importance of Steroid Uptake and Intracrine Action in Endometrial and Ovarian Cancers

Endometrial and ovarian cancers predominately affect women after menopause, and are more frequently observed in developed countries. These are considered to be hormone-dependent cancers, as steroid hormones, and estrogens in particular, have roles in their onset and progression. After the production of estrogens in the ovary has ceased, estrogen synthesis occurs in peripheral tissues. This depends on the cellular uptake of estrone-sulfate and dehydroepiandrosterone-sulfate, as the most important steroid precursors in the plasma of postmenopausal women. The uptake through transporter proteins, such as those of the organic anion-transporting polypeptide (OATP) and organic anion-transporter (OAT) families, is followed by the synthesis and action of estradiol E2. Here, we provide an overview of the current understanding of this intracrine action of steroid hormones, which depends on the availability of the steroid precursors and transmembrane transporters for precursor uptake, along with the enzymes for the synthesis of E2. The data is also provided relating to the selected transmembrane transporters from the OATP, OAT, SLC51, and ABC-transporter families, and the enzymes involved in the E2-generating pathways in cancers of the endometrium and ovary. Finally, we discuss these transporters and enzymes as potential drug targets.

Iron regulatory protein 2 in ovarian endometrial cysts

Ovarian endometrial cysts cause some kinds of ovarian cancer, and iron is considered as one factor of carcinogenesis. In contrast, hypoxia is associated with progression, angiogenesis, metastasis, and resistance to therapy in cancer. We investigated hypoxia-induced perturbation of iron homeostasis in terms of labile iron, iron deposition, and iron regulatory protein (IRP) in ovarian endometrial cysts. Iron deposition, expression of IRPs, and a protein marker of hypoxia in human ovarian endometrial cysts were analyzed histologically. The concentration of free iron and the pO₂ level of the cyst fluid of human ovarian cysts (n = 9) were measured. The expression of IRP2 under hypoxia was investigated in vitro by using Ishikawa cells as a model of endometrial cells. Iron deposition and the expression of IRP2 and Carbonic anhydrase 9 (CA9) were strong in endometrial stromal cells in the human ovarian endometrial cysts. The average concentration of free iron in the cyst fluid was 8.1 ± 2.9 mg/L, and the pO₂ was 22.4 ± 5.2 mmHg. A cell-based study using Ishikawa cells revealed that IRP2 expression was decreased by an overload of Fe(II) under normoxia but remained unchanged under hypoxia even in the presence of excess Fe(II). An increase in the expression of IRP2 caused upregulation of intracellular iron as a result of the response to iron deficiency, whereas the protein was degraded under iron-rich conditions. We found that iron-rich regions existed in ovarian endometrial cysts concomitantly with the high level of IRP2 expression, which should generally be decomposed upon an overload of iron. We revealed that an insufficient level of oxygen in the cysts is the main factor for the unusual stabilization of IRP2 against iron-mediated degradation, which provides aberrant uptake of iron in ovarian endometrial stromal cells and can potentially lead to carcinogenesis.

The Important Roles of Steroid Sulfatase and Sulfotransferases in Gynecological Diseases

Gynecological diseases such as endometriosis, adenomyosis and uterine fibroids, and gynecological cancers including endometrial cancer and ovarian cancer, affect a large proportion of women. These diseases are estrogen dependent, and their progression often depends on local estrogen formation. In peripheral tissues, estrogens can be formed from the inactive precursors dehydroepiandrosterone sulfate and estrone sulfate. Sulfatase and sulfotransferases have pivotal roles in these processes, where sulfatase hydrolyzes estrone sulfate to estrone, and dehydroepiandrosterone sulfate to dehydroepiandrosterone, and sulfotransferases catalyze the reverse reactions. Further activation of estrone to the most potent estrogen, estradiol, is catalyzed by 17-ketosteroid reductases, while estradiol can also be formed from dehydroepiandrosterone by the sequential actions of 3β-hydroxysteroid dehydrogenase-Δ⁴-isomerase, aromatase, and 17-ketosteroid reductase. This review introduces the sulfatase and sulfotransferase enzymes, in terms of their structures and reaction mechanisms, and the regulation and different transcripts of their genes, together with the importance of their currently known single nucleotide polymorphisms. Data on expression of sulfatase and sulfotransferases in gynecological diseases are also reviewed. There are often unchanged mRNA and protein levels in diseased tissue, with higher sulfatase activities in cancerous endometrium, ovarian cancer cell lines, and adenomyosis. This can be indicative of a disturbed balance between the sulfatase and sulfotransferases enzymes, defining the potential for sulfatase as a drug target for treatment of gynecological diseases. Finally, clinical trials with sulfatase inhibitors are discussed, where two inhibitors have already concluded phase II trials, although so far with no convincing clinical outcomes for patients with endometrial cancer and endometriosis.

Moving Toward Integrating Gene Expression Profiling Into High-Throughput Testing: A Gene Expression Biomarker Accurately Predicts Estrogen Receptor α Modulation in a Microarray Compendium

Microarray profiling of chemical-induced effects is being increasingly used in medium- and high-throughput formats. Computational methods are described here to identify molecular targets from whole-genome microarray data using as an example the estrogen receptor α (ERα), often modulated by potential endocrine disrupting chemicals. ERα biomarker genes were identified by their consistent expression after exposure to 7 structurally diverse ERα agonists and 3 ERα antagonists in ERα-positive MCF-7 cells. Most of the biomarker genes were shown to be directly regulated by ERα as determined by ESR1 gene knockdown using siRNA as well as through chromatin immunoprecipitation coupled with DNA sequencing analysis of ERα-DNA interactions. The biomarker was evaluated as a predictive tool using the fold-change rank-based Running Fisher algorithm by comparison to annotated gene expression datasets from experiments using MCF-7 cells, including those evaluating the transcriptional effects of hormones and chemicals. Using 141 comparisons from chemical- and hormone-treated cells, the biomarker gave a balanced accuracy for prediction of ERα activation or suppression of 94% and 93%, respectively. The biomarker was able to correctly classify 18 out of 21 (86%) ER reference chemicals including "very weak" agonists. Importantly, the biomarker predictions accurately replicated predictions based on 18 in vitro high-throughput screening assays that queried different steps in ERα signaling. For 114 chemicals, the balanced accuracies were 95% and 98% for activation or suppression, respectively. These results demonstrate that the ERα gene expression biomarker can accurately identify ERα modulators in large collections of microarray data derived from MCF-7 cells.