HEC-1A Endometrial Cancer Cell Lines Research Articles

Effects of RFRP‑3 on an ovariectomized estrogen‑primed rat model and HEC‑1A human endometrial carcinoma cells.

The hypothalamic peptide gonadotropin inhibitory hormone (GnIH) is a relatively novel hypothalamic neuropeptide, identified in 2000. It can influence the hypothalamic-pituitary-gonadal axis and reproductive function through various neuroendocrine systems. The present study aimed to explore the effects and potential underlying molecular mechanism of RFamide-related peptide-3 (RFRP-3) injection on the uterine fluid protein profile of ovariectomized estrogen-primed (OEP) rats using proteomics. In addition, the possible effects of RFRP-3 on the viability and apoptosis of the human endometrial cancer cell line HEC-1A and associated molecular mechanism were investigated. The OEP rat model was established through injection with GnIH/RFRP-3 through the lateral ventricle. At 6 h after injection, the protein components of uterine fluid of rats in the experimental and control groups were analyzed using liquid chromatography (LC)-tandem mass spectrometry (MS/MS). Differentially expressed proteins (DEPs) were analyzed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Protein-protein interactions (PPI) were investigated using the STRING database. PPI networks were then established before hub proteins were selected using OmicsBean software. The expression of one of the hub proteins, Kras, was then detected using western blot analysis. Cell Counting Kit-8, Annexin V-FITC/PI, reverse transcription-quantitative PCR and western blotting were also performed to analyze cell viability and apoptosis. In total, 417 DEPs were obtained using LC-MS/MS, including 279 upregulated and 138 downregulated proteins. GO analysis revealed that the majority of the DEPs were secretory proteins. According to KEGG enrichment analysis, the DEPs found were generally involved in tumor-associated pathways. In particular, five hub proteins, namely G protein subunit α (Gna)13, Gnaq, Gnai3, Kras and MMP9, were obtained following PPI network analysis. Western blot analysis showed that expression of the hub protein Kras was downregulated following treatment with 10,000 ng/ml RFRP-3. RFRP-3 treatment (10,000 ng/ml) also suppressed HEC-1A cell viability, induced apoptosis, downregulated Bcl-2 and upregulated Bax protein expression, compared with those in the control group. In addition, compared with those in the control group, RFRP-3 significantly reduced the mRNA expression levels of PI3K, AKT and mTOR, while upregulating those of LC3-II. Compared with those in the control group, RFRP-3 significantly decreased the protein expression levels of PI3K, AKT, mTOR and p62, in addition to decreasing AKT phosphorylation. By contrast, RFRP-3 significantly increased the LC3-II/I ratio and G protein-coupled receptor 147 (GPR147) protein expression. In conclusion, the present data suggest that RFRP-3 can alter the protein expression profile of the uterine fluid of OEP rats by upregulating MMP9 expression whilst downregulating that of key hub proteins Gna13, GnaQ, Gnai3 and Kras. Furthermore, RFRP-3 can inhibit HEC-1A cell viability while promoting apoptosis. The underlying molecular mechanism may involve activation of GPR147 receptor by the direct binding of RFRP-3, which further downregulates the hub protein Kras to switch on the PI3K/AKT/mTOR pathway. This subsequently reduces the Bcl-2 expression and promotes Bax expression to induce autophagy.

Pentamidine inhibits proliferation, migration and invasion in endometrial cancer via the PI3K/AKT signaling pathway

BackgroundPentamidine has been reported to have many pharmacological effects including anti- protozoal, anti-inflammatory, and anti-tumor activities. The aim of this study is to investigate the potential therapeutic role of Pentamidine and molecular mechanisms of Pentamidine on PI3K/AKT signaling pathway underlying the anti-tumor properties in endometrial cancer.MethodsOur study was carried out in the central laboratory of Harbin Medical University from 2019 to 2021. Human endometrial cancer cell lines Ishikawa and HEC-1A were treated with Pentamidine. The proliferation ability of cells was investigated by MTS and colony formation assays. The cell cycle distribution was detected by flow cytometry. Cell migration and invasion were analyzed by using the wound healing assay and Transwell assay. Western blotting was performed to measure the levels of AKT, p-AKT, MMP-2, and MMP-9.ResultsOur results revealed that treatment of Pentamidine inhibited proliferation, migration and invasion of Ishikawa and HEC-1A endometrial cancer cells. Mechanistic investigation showed that Pentamidine inhibited PI3K/AKT signaling pathway and also reduced the expression of MMP-2 and MMP-9. In addition, co-treatment with PI3K kinase inhibitor LY294002 and Pentamidine leaded to increased repression of cell viability and the protein expression of p-AKT in Ishikawa cells.ConclusionsPentamidine suppresses PI3K/AKT signaling pathway, and inhibits proliferation, migration and invasion of EC cells. These findings suggested that Pentamidine might be a potential candidate for treating EC through PI3K/AKT pathway.

Antitumorigenic effect of combination treatment with ONC201 and TRAIL in endometrial cancer in vitro and in vivo

ABSTRACT ONC201 demonstrated promising activity in patients with advanced endometrial cancer in a Phase I clinical trial. ONC201 activates the integrated stress response (ISR) and upregulates TRAIL and its receptor DR5. We hypothesized ONC201 upregulation of DR5 could sensitize tumors to TRAIL and combination of ONC201 and TRAIL would lead to enhanced cell death in endometrial cancer models. Five endometrial cancer cell lines AN3CA, HEC1A, Ishikawa, RL952, and KLE as well as a murine xenograft model were treated with ONC201 alone or in combination with TRAIL. ONC201 decreased the cell viability of all five endometrial cancer cell lines at clinically achievable low micro-molar concentrations (2–4 μM). ONC201 activated the ISR and induced protein expression of TRAIL and DR5 at the cell surface. Pretreatment with ONC201 sensitized endometrial cancer cell lines to TRAIL, leading to increased cell death induction compared to either agent alone. Tumor growth was reduced in vivo by the ONC201/TRAIL combination treatment in the xenograft model of endometrial cancer (p = .014). Mice treated with combination treatment survived significantly longer than mice from the three control groups (p = .018). ONC201 decreased cell viability in endometrial cancer cells lines primarily through growth arrest while the combination of ONC201 and TRAIL promoted cell death in vitro and in vivo. Our results suggest a novel cancer therapeutic strategy that can be further investigated in the clinic.

P–284 Changes in protein expression due to metformin treatment and hyperinsulinemia in a human endometrial cancer cell line

Abstract Study question The aim of the study was to identify new target proteins/pathways that are affected by metformin treatment in endometrial cancer cells in a proteomic approach. Summary answer The expression of 1,300 different proteins were investigated, of which 80 proteins with the most prominent changes were presented and some discussed in detail. What is known already The incidence of endometrial cancer (EC) has increased over the past years. Metabolic diseases such as obesity, type II diabetes mellitus (T2DM), and associated conditions (i.e. polycystic ovary syndrome (PCOS), insulin resistance) lead to elevated levels of circulating estrogens, which promote EC development and progression. Metformin, an insulin-sensitizing biguanide drug, commonly used in the treatment of T2DM, especially in obese patients, displayed anti-cancer effects in various cancer types, including EC. Different 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. Study design, size, duration In the present in vitro study, EC cells were cultured in 5.5 mmol/L glucose medium (supplemented with 10 nmol/L ß-estradiol (E2)) and treated with metformin (0.5 mmol/L), insulin (100 ng/mL), or remained untreated for 7 d. The expression of 1,300 different proteins was detected in cellular extracts in an affinity proteomic approach and compared between the treatment groups in order to identify potential target proteins and pathways that contribute to the anti-cancer effects of metformin. Participants/materials, setting, methods The study was carried out with the EC cell line HEC–1A that represents a postmenopausal model with low E2 sensitivity. Proteins were extracted, quantified with the BCA assay, and protein expression was analyzed using the scioDiscover antibody microarray. Differences in protein abundance between samples were presented as log2-fold changes (log2FC) with significance for samples that displayed |log2FC| ≥ 0.5 and adjusted p ≤ 0.05. Pathway analysis was carried out with the STRING and DAVID databases. Main results and the role of chance 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. Results for the 80 most affected proteins were presented and the consequences for the cells resulting from the detected expression changes were discussed in detail for several proteins. The presented data helps identify potential target proteins and pathways 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. Limitations, reasons for caution The results were obtained from an in vitro study with human cancer cell lines, and thus cannot be easily extrapolated to patients. Wider implications of the findings: In the context of a hyperinsulinemic environment, further proteins might be of interest, i.e. AMFR, CCND2, CD63, ERBB3, EZR, GFAP, IRF4, PI3, PLCG2, SORL1, VEGFA, VTCN1, SPP1, and TM9SF2. Here, a metformin-induced insulin-sensitization might be able to counteract unfavorable effects on protein expression profile that have been induced by hyperinsulinemia. Trial registration number Not applicable

Abstract PO049: Compartment-specific profiling for evaluation of disrupted signaling in early stage, low-grade endometrial cancer

Abstract Understanding tumor microenvironment is critical to improving conservative management (non-surgical) strategies for early stage, low grade endometrial cancer (EC). This remains an unmet clinical need for women who wish to maintain fertility and those who cannot undergo surgery due to medical co-morbidities. Current regimens rely on progestin treatment, but resistance and early relapse require improved therapeutic strategies. We sought to evaluate alterations in gene expression in the epithelial and stromal compartment of EC compared to normal endometrium to identify targets for combination therapies. RNA was extracted from microdissected epithelial and stromal compartments of formalin fixed paraffin embedded early stage, low grade EC and normal endometrium (NE). Comprehensive transcriptome profiling was performed with Affymetrix Clariom D assay and pathway analysis was performed. Immunohistochemistry (IHC) was used for validation. Functional studies of differentially expressed genes were performed in Hec1A EC cell lines. Among differentially expressed genes in EC vs NE, multiple altered signaling pathways were identified. EIF2 signaling, eIF4 and p70S6K signaling, and PI3K/AKT/mTOR were the most significant pathways activated in both epithelial and stromal compartments. In the epithelia compartment, the most significant gene expression changes included reduced expression of RBPMS (RNA Binding Protein with Multiple Splicing), SORD (Sorbitol Dehydrogenase), DDX17 (DEAD-Box Helicase 17), and TPT1 (Translationally-Controlled Tumor Protein) in EC, while MTDH (Metadherin) was significantly increased in EC. Similar changes were observed in the stroma compartment, but with lower fold changes than that observed in gland. Together with decreased RBPMS expression, decreased RBPMS-interacting molecules IGF2, TCF7L2 (Transcription Factor 7 Like 2), FOS (Proto-Oncogene C-Fos) and increased GPS2 (G protein Pathway Suppressor 2) were also observed. Differential expression of proteins in gland and stroma was also confirmed by IHC. An inverse correlation of RBPMS expression and EC proliferation was also observed in EC at the protein level. Enhanced AKT and S6 protein phosphorylation were observed by RBPMS silencing in Hec1A endometrial cells. Reverse Phase Protein Array demonstrated activation of Caveolin 1, FOXO3 (Forkhead Box O3), MT-CO1 (Mitochondrially Encoded Cytochrome C Oxidase I), L1CAM (L1 Cell Adhesion Molecule) with RBPMS silencing in Hec1A cell. These molecules are involved in pathways such as molecular mechanisms of cancer, estrogen receptor signaling, and senescence pathway. While estrogen-regulated changes were prominent in early stage low-grade EC, the identification of additional signaling changes provide support for an ongoing trial of levonorgestrel IUD + everolimus (mTOR inhibitor) and can be probed further to identify new targets for combination conservative management strategies. Additionally, biomarkers from these pathways, such as RBPMS, can be studied to guide the selection of progestin-only therapy versus combination therapy. Citation Format: Qian Zhang, Xiaoping Su, Joseph Celestino, Ying Yuan, Samuel C. Mok, Karen H. Lu, Melinda S. Yates. Compartment-specific profiling for evaluation of disrupted signaling in early stage, low-grade endometrial cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO049.

Long-Term Metformin Effect on Endometrial Cancer Development Depending on Glucose Environment <i>In Vitro</i>

Objectives: Hyperinsulinemia as well as prolonged and elevated estrogen exposure are considered as risk factors for endometrial cancer (EC) development. Metformin, an anti-hyperglycemic and insulin-sensitizing biguanide, displayed anti-proliferative effects in recent studies. In the present study, the effects of long-term exposure of endometrial cancer cells to low and moderate concentrations of metformin on cell viability, proliferation, clonogenicity and migration were investigated under different metabolic conditions. Study Design: EC cell lines HEC-1A and Ishikawa were cultured under normo- (NG, 5.5 mM) or hyperglycemic (HG, 17.0 mM) conditions and treated with metformin (0.01 - 5.0 mM) in the presence of β-estradiol (E2) for 7 d. Results: A concentration-dependent decrease of cellular viability was observed in the MTT and ATP assays after metformin treatment. IC50 values were between 0.7 - 3.7 mM (NG) and 3.0 - 18.3 mM (HG), respectively. A protective effect of glucose on cellular viability was detected only in the ATP assay. Furthermore, metformin (0.5 - 5.0 mM) led to a significant decrease in proliferation by 12% - 55% (NG). However, a decreased proliferation rate was only induced at 5.0 mM metformin (40%) in the presence of high glucose levels in HEC-1A cells, indicating a glucose-related resistance to anti-proliferative metformin effects, which—to a lesser extent—was also observed in Ishikawa cells. Metformin treatment also caused concentration-dependent effects on clonogenicity and decreased the number and size of colonies. In HEC-1A cells, metformin (0.5 - 5.0 mM) reduced the colony formation by 44% - 80% (NG) and 29% - 81% (HG), respectively. Slightly higher metformin concentrations (1.0 - 5.0 mM) were necessary in Ishikawa cells to reduce clonogenicity by 36% - 86% independent of glucose levels. An investigation of migration in the wound healing assay revealed that the % wound closure decreased with increasing metformin concentrations, but independent of glucose levels. After treatment with 5.0 mM metformin, migration was significantly reduced in both cell lines. Conclusion: Our in vitro findings support the hypothesis that metformin has a direct effect on endometrial cancer cell lines and reflects the importance of the local glucose environment, suggesting that metformin may be considered as a potential adjuvant agent in endometrial cancer therapy due to its direct and indirect effects on endometrial development. However, further studies are necessary that confirm the relevance of our data for clinical applications.

MTOR-Dependent Role of Sestrin2 in Regulating Tumor Progression of Human Endometrial Cancer.

Simple SummaryMammalian target of rapamycin complex 1 (mTORC1), a key controller of growth and environmental stress signaling, is frequently activated in human cancers. Sestrin2 (SESN2), a highly conserved stress-inducible protein, is one of the negative feedback mechanisms for inhibiting chronic activation of mTORC1. This study aimed to investigate the expression and clinical implications of SESN2 in endometrial cancer using an in vitro and in vivo approach. The analysis indicated increased levels of SESN2 and mTORC1 pathway activity in cancer tissues than in normal tissues. High SESN2 expression correlated with shorter patient survival duration. However, lentiviral overexpression of SESN2 and mTOR inhibitors suppressed cancer cell proliferation, migration, and epithelial–mesenchymal transition. Our study provides strong evidence for prognostic significance of SESN2, and its association with mTORC1 pathway and endometrial cancer growth. Thus, the results identified SESN2 as a potential therapeutic target in endometrial cancer.Oncogenic activation of the mammalian target of rapamycin complex 1 (mTORC1) leads to endometrial cancer cell growth and proliferation. Sestrin2 (SESN2), a highly conserved stress-inducible protein, is involved in homeostatic regulation via inhibition of reactive oxygen species (ROS) and mTORC1. However, the role of SESN2 in human endometrial cancer remains to be investigated. Here, we investigated expression, clinical significance, and underlying mechanisms of SESN2 in endometrial cancer. SESN2 was upregulated more in endometrial cancer tissues than in normal endometrial tissues. Furthermore, upregulation of SESN2 statistically correlated with shorter overall survival and disease-free survival in patients with endometrial cancer. SESN2 expression strongly correlated with mTORC1 activity, suggesting its impact on prognosis in endometrial cancer. Additionally, knockdown of SESN2 promoted cell proliferation, migration, and ROS production in endometrial cancer cell lines HEC-1A and Ishikawa. Treatment of these cells with mTOR inhibitors reversed endometrial cancer cell proliferation, migration, and epithelial–mesenchymal transition (EMT) marker expression. Moreover, in a xenograft nude mice model, endometrial cancer growth increased by SESN2 knockdown. Thus, our study provides evidence for the prognostic significance of SESN2, and a relationship between SESN2, the mTORC1 pathway, and endometrial cancer growth, suggesting SESN2 as a potential therapeutic target in endometrial cancer.

Study of the Characterization of Side Population Cells in Endometrial Cancer Cell Lines: Chemoresistance, Progestin Resistance, and Radioresistance.

Introduction: Radiotherapy, combined regimens as platinum-paclitaxel chemotherapy and/or endocrine therapy is an important adjuvant treatment after surgery for endometrial cancer (EC). While, the resistance to them remain unclear. In our study, to separate the characteristics of side population (SP) cells from EC cell lines, study the mechanism of Taxol-resistance, progestin resistance and radioresistanc, and provide the basic for EC.Methods: SP cells from EC cell lines HEC-1A, Ishikawa and RL95-2 were separated by Hoechst 33342 staining and flow cytometry analysis. The expression of breast cancer resistance protein (BCRP) in SP cells and non-SP cells from HEC-1A was examined by immunocytochemistry, and the radiation-resistant and Taxol-resistant characteristics of SP cells and non-SP cells were compared by MTS. Ishikawa, Ishikawa-SP, and Ishikawa-non-SP cells incubated with MPA were selected for cell apoptosis assays by using flow cytometry. The expression of caspase-3 was examined by immunocytochemistry, and autophagy was detected by MDC staining.Results: Small proportions of SP cells, namely, 1.44 ± 0.93%, 2.86 ± 3.09%, and 2.87 ± 1.29%, were detected in HEC-1A, Ishikawa and RL95-2, respectively. There was a stronger clone formation efficiency for the SP cells than for non-SP cells in HEC-1A [(6.02 ± 1.17) vs. (0.53±0.20)%, P = 0.001], and there was a significant difference in the rate of tumourigenicity between the SP cells and non-SP cells in HEC-1A (87.5 vs. 12.5%). There were higher levels of BCRP expression (P = 0.001) and resistance to Taxol and radiation (P < 0.05) in the SP cells than in non-SP cells. After MPA treatment, the apoptosis rates were significantly different among the Ishikawa, Ishikawa-SP and Ishikawa-non-SP groups [(4.64 ± 0.18)%, (4.01 ± 0.43)%, and (9.3 ± 0.67)%; (P = 0.05)], and the expression of Caspase-3 in the Ishikawa group was higher than that in Ishikawa-SP group. The autophagic activity of the Ishikawa-SP cells was the strongest, while the autophagic activity of Ishikawa-non-SP was the weakest.Conclusions: There is a significant enrichment in SP cells among different EC cell lines, and these SP cells be more resistant to Taxol, MPA and radiation therapy. The overexpression of BCRP among SP cells may be the cause of resistance to Taxol, progestin and radiotherapy, which may be related to apoptosis and autophagic activity.

PCOS serum-derived exosomal miR-27a-5p stimulates endometrial cancer cells migration and invasion.

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-age women. Women with PCOS have a 2.7-fold increased risk for developing endometrial cancer (EC). This study was performed to investigate the potential stimulatory effects of serum exosomes isolated from patients with PCOS on EC cell lines and to explore the underlying mechanism. EC cell lines exposed to exosomes derived from PCOS patients serum exhibited an enhanced migration and invasion phenotype. Next, sequence-based analysis of exosomal miRNA was conducted to screen the differentially expressed miRNAs in serum exosomes from PCOS patients and normal controls. The levels of 55 mature miRNAs significantly differed in serum exosomes from PCOS patients compared with those from normal controls. Real-time PCR was used to verify the expression of eight of these miRNAs, among which miR-27a-5p was the most significantly elevated in PCOS patients serum exosomes. The role of miR-27a-5p in EC migration and invasion was further investigated via miR-27a-5p mimics or inhibitor transfection in Ishikawa and HEC-1A EC cell lines. In addition, the SMAD4 gene was identified as the target of miR-27a-5p by several target prediction databases and was validated by a luciferase assay. SMAD4 mRNA and protein levels were downregulated in EC cells transfected with the miR-27a-5p mimics, but upregulated in cells transfected with the miR-27a-5p inhibitor. Furthermore, in vitro experiments results confirmed that miR-27a-5p prohibited migration and invasion via SMAD4 downregulation. Thus, serum exosomal miR-27a-5p may play a role in EC development in PCOS patients.

Restoration of microRNA-29c in type I endometrioid cancer reduced endometrial cancer cell growth.

Endometrial cancer is the most common gynaecological cancer worldwide, and the prognosis of patients with advanced disease remains poor. MicroRNAs (miRs) are dysregulated in endometrial cancer. miRs-29-a, -b and -c expression levels are downregulated in endometrial cancer; however, a specific role for miR-29c and its target genes remain to be elucidated. The aim of the present study was to determine the functional effect of restoring miR-29c expression in endometrial cancer cell lines and to identify miR-29c targets involved in cancer progression. miR-29c expression in human endometrial tumour grades 1-3 and benign tissue as well as in the endometrial cancer cell lines Ishikawa, HEC1A and AN3CA were analysed using reverse transcriptase-quantitative PCR (RT-qPCR). The cell lines were transfected with miR-29c mimic, miR-29c inhibitor or scrambled control. xCELLigence real-time cell monitoring analysed proliferation and migration, and flow cytometry was used to analyse apoptosis and cell cycle. The expression of miR-29c target genes in transfected cell lines was analysed using RT-qPCR. miR-29c was downregulated in grade 1-3 endometrial cancer samples compared with benign endometrium. miR-29c was reduced in Ishikawa and AN3CA cells, but not in HEC1A cell lines compared with non-cancerous primary human endometrial epithelial cells. Overexpression of miR-29c variably reduced proliferation, increased apoptosis and reduced the expression levels of miR-29c target genes, including cell division cycle 42, HMG-box transcription factor 1, integrin subunit β 1, MCL1 apoptosis regulator BCL2 family member, MDM2 proto-oncogene, serum/glucocorticoid regulated kinase 1, sirtuin 1 and vascular endothelial growth factor A, across the three cell lines investigated. Inhibition of miR-29c in HEC1A cells increased proliferation and collagen type IV α 1 chain expression. The re-introduction of miR-29c to endometrial cancer cell lines reduced proliferation, increased apoptosis and reduced miR-29c target gene expression in vitro. The present results suggested that miR-29c may be a potential therapeutic target for endometrial cancer.

Abstract 262: Anti-tumorigenic effect of ONC201 is enhanced by combination treatment with TRAIL or a DR5 agonist in endometrial cancer in vitro

Abstract ONC201 is a well-tolerated, orally active small molecule in the novel imipridone class that has anti-tumorigenic properties in a number of solid tumors, but not in non-neoplastic cells. ONC201 has demonstrated promising activity as a single agent in patients with advanced endometrial cancer in the first-in-human clinical trial with Phase II trials in endometrial cancer patients now underway. Although the mechanism of action in endometrial cell pathology has not been well studied, ONC201’s anti-tumor effect has been shown in other model systems to be p53-independent and mediated through activation of the integrated stress response (ISR) leading to DR5 activation and through induction of cell death or growth arrest. ONC201 inhibits ERK and AKT leading to upregulation of TRAIL in many systems. We hypothesized that ONC201 upregulation of DR5 could sensitize tumor cells to TRAIL and that TRAIL could convert growth arrest to cell death in ONC201-treated cells. Three endometrial cancer cell lines AN3CA, HEC1A and KLE were treated with ONC201 alone or in combination with TRAIL, or a DR5 agonist. Effects on cell viability were assessed by the Cell Titer-Glo cell viability assay, colony formation assays and cell cycle analysis by propidium iodide staining. QPCR and Western blot analysis were used to evaluate mRNA and protein expression, respectively. Assessment of TRAIL and DR5 cell surface expression was evaluated by surface staining using flow cytometry and FlowJo data analysis. ONC201 decreased the cell viability of all three endometrial cancer cell lines at clinically achievable low micro-molar concentrations. ONC201 activated the ISR and an anti-proliferative effect involving a G1 phase arrest and little cell death as indicated by increased Sub-G1 analysis and PARP cleavage. DR5 mRNA and protein expression at the cell surface were induced by ONC201. All three endometrial cancer cell lines were resistant to TRAIL alone, however, pre-treatment with ONC201 sensitized the AN3CA and KLE to TRAIL and a DR5 agonist, leading to potent cell death induction. The combination of ONC201 plus TRAIL did not cause appreciable cell death in normal human fibroblast. ONC201 decreases cell viability in endometrial cancer cells lines primarily through growth arrest while the combination of ONC201 and TRAIL or a DR5 agonist promotes cell death in AN3CA and KLE cells but not in HEC1A endometrial cancer cells. Our results suggest a novel cancer therapeutic strategy that can be exploited in the clinic. Citation Format: Jocelyn Ray, Marie Ralff, David Dicker, Wafik El-Deiry. Anti-tumorigenic effect of ONC201 is enhanced by combination treatment with TRAIL or a DR5 agonist in endometrial cancer in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 262.

High throughput silencing identifies novel genes in endometrioid endometrial cancer

ObjectiveTo validate the gene expression profile obtained from the previous microarray analysis and to further study the biological functions of these genes in endometrial cancer. From our previous study, we identified 621 differentially expressed genes in laser-captured microdissected endometrioid endometrial cancer as compared to normal endometrial cells. Among these genes, 146 were significantly up-regulated in endometrial cancer. Materials and MethodsA total of 20 genes were selected from the list of up-regulated genes for the validation assay. The qPCR confirmed that 19 out of the 20 genes were up-regulated in endometrial cancer compared with normal endometrium. RNA interference (RNAi) was used to knockdown the expression of the upregulated genes in ECC-1 and HEC-1A endometrial cancer cell lines and its effect on proliferation, migration and invasion were examined. ResultsKnockdown of MIF, SOD2, HIF1A and SLC7A5 by RNAi significantly decreased the proliferation of ECC-1 cells (p < 0.05). Our results also showed that the knockdown of MIF, SOD2 and SLC7A5 by RNAi significantly decreased the proliferation and migration abilities of HEC-1A cells (p < 0.05). Moreover, the knockdown of SLC38A1 and HIF1A by RNAi resulted in a significant decrease in the proliferation of HEC1A cells (p < 0.05). ConclusionWe have identified the biological roles of SLC38A1, MIF, SOD2, HIF1A and SLC7A5 in endometrial cancer, which opens up the possibility of using the RNAi silencing approach to design therapeutic strategies for treatment of endometrial cancer.

MiR-302a-5p/367-3p-HMGA2 axis regulates malignant processes during endometrial cancer development

BackgroundMetastasis is one of the main reasons for treatment failure in endometrial cancer. Notably, high mobility group AT-hook 2 (HMGA2) has been recognized as a driving factor of tumour metastasis. microRNAs (miRNAs) are powerful posttranscriptional regulators of HMGA2.MethodsThe binding sites of miR-302a-5p and miR-367-3p on HMGA2 mRNA were identified using bioinformatics prediction software and were validated via luciferase assay. The expression levels of miR-302a-5p and miR-367-3p were detected using quantitative real-time PCR and in situ hybridization. Western blotting and immunohistochemistry were used to detect the levels of HMGA2 and epithelial-mesenchymal transition pathway-related proteins. Co-immunoprecipitation was used to detect protein interactions. The roles of miR-302a-5p and miR-367-3p in the regulation of HMGA2 during the progression of endometrial cancer were investigated using both in vitro and in vivo assays.ResultsIn the present study, high HMGA2 expression was correlated with poor clinical outcomes in endometrial cancer. The binding sites of miRNAs on HMGA2 mRNA were identified using bioinformatics prediction software and were validated via luciferase assay. In the endometrial cancer cell lines Ishikawa and HEC-1A, the overexpression of miR-302a-5p/367-3p significantly inhibited the expression of HMGA2 mRNA. In endometrial cancer tissues, we showed that miR-302a-5p and miR-367-3p were significantly downregulated and thus inversely correlated with HMGA2. The miR-302a-5p and miR-367-3p expression levels were closely correlated with FIGO stage and lymph node metastasis. High expression of miR-302a-5p/367-3p was correlated with high survival rates in endometrial cancer. In addition, miR-302a-5p/367-3p suppressed the malignant behaviour of endometrial carcinoma cells via the inhibition of HMGA2 expression.ConclusionOur findings indicate that miR-302a-5p/367-3p-mediated expression of HMGA2 regulates the malignant behaviour of endometrial carcinoma cells, which suggests that the miR-302a-5p/367-3p-HMGA2 axis may be a predictive biomarker of endometrial cancer metastasis and patient survival and a potential therapeutic target in metastatic endometrial cancer.

Preclinical data supporting the flavone baicalein as a novel mTOR inhibitor with potent activity against endometrial cancer cells

Objectives: The mTOR pathway is a promising target for endometrial cancer therapy commonly because of the loss of PTEN expression. Metformin has been shown to inhibit endometrial cancer cell proliferation and is currently in phase II/III clinical trial testing. We have identified a natural flavone, baicalein, which markedly upregulates DNA Damage Induced Transcript 4 (DDIT4), suppresses breast and ovarian cancer cell growth, and alters mTOR pathway. We examined the activity of baicalein in endometrial cancer cells. Methods: The endometrial cancer cell line HEC1a was treated with baicalein (5–80 μM) or metformin (5–10,000 μM) and growth was assessed at 24 to 72 hours with the MTT assay. Total protein lysates were obtained for Western blot analysis to evaluate mTOR pathway mediators and DDIT4 levels. In vivo studies were performed with an HEC1a mouse model. Mice received either control or baicalein (80 mg/kg) treatment by oral gavage daily. Tumor volumes were measured over time. Results: Baicalein inhibited growth of HEC1a cell line in a dose-dependent fashion (IC50 ~10 μM). In contrast, higher millimolar concentrations (>1,000-fold) were required to inhibit growth with metformin. The observed growth inhibition with baicalein was associated with decreased PS6K1 and PS6 levels and increased DDIT4 levels. We tested baicalein (80 mg/kg) in an endometrial cancer cell mouse model. We observed significant tumor growth inhibition in the HEC1A mouse model compared with control mice. (See Fig. 1.) Conclusions: Both in vitro and in vivo studies support baicalein as a potent inhibitor of endometrial cancer cell proliferation. The inhibitory effect correlates with mTOR pathway inhibition and increase in DDIT4 expression. This preclinical study supports the use of baicalein as a novel treatment for endometrial cancer.

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

Estrogens have important roles in the pathogenesis of endometrial cancer. They can have carcinogenic effects through stimulation of cell proliferation or formation of DNA-damaging species. To characterize model cell lines of endometrial cancer, we determined the expression profiles of the estrogen receptors (ERs) ESR1, ESR2 and GPER, and 23 estrogen biosynthetic and metabolic genes, and investigated estrogen biosynthesis in the control HIEEC cell line and the Ishikawa and HEC-1A EC cell lines. HIEEC and Ishikawa expressed all ERs to different extents, while HEC-1A cells lacked expression of ESR1. Considering the estrogen biosynthetic and metabolic enzymes, these cells showed statistically significant different gene expression profiles for SULT2B1, HSD3B2, CYP19A1, AKR1C3, HSD17B1, HSD17B7, HSD17B12, CYP1B1, CYP3A5, COMT, SULT1A1, GSTP1 and NQO2. In these cells, E2 was formed from E1S and E1, while androstenedione was not converted to estrogens. HIEEC and Ishikawa had similar profiles of androstenedione and E1 metabolism, but hydrolysis of E1S to E1 was weaker in Ishikawa cells. HEC-1A cells were less efficient for activation of E1 into the potent E2, but metabolized androstenedione to other androgenic metabolites better than HIEEC and Ishikawa cells. This study reveals that HIEEC, Ishikawa, and HEC-1A cells can all form estrogens only via the sulfatase pathway. HIEEC, Ishikawa, and HEC-1A cells expressed all the major genes in the production of hydroxyestrogens and estrogen quinones, and in their conjugation. Significantly higher CYP1B1 mRNA levels in Ishikawa cells compared to HEC-1A cells, together with lack of UGT2B7 expression, indicate that Ishikawa cells can accumulate more toxic estrogen-3,4-quinones than HEC-1A cells, as also for HIEEC cells. This study provides further characterization of HIEEC, Ishikawa, and HEC-1A cells, and shows that they differ greatly in expression of the genes investigated and in their capacity for E2 formation, and thus they represent different in vitro models.

Molecular profiling of circulating tumor cells links plasticity to the metastatic process in endometrial cancer.

BackgroundAbout 20% of patients diagnosed with endometrial cancer (EC) are considered high-risk with unfavorable prognosis. In the framework of the European Network for Individualized Treatment in EC (ENITEC), we investigated the presence and phenotypic features of Circulating Tumor Cells (CTC) in high-risk EC patients.MethodsCTC isolation was carried out in peripheral blood samples from 34 patients, ranging from Grade 3 Stage IB to Stage IV carcinomas and recurrences, and 27 healthy controls using two methodologies. Samples were subjected to EpCAM-based immunoisolation using the CELLection™ Epithelial Enrich kit (Invitrogen, Dynal) followed by RTqPCR analysis. The phenotypic determinants of endometrial CTC in terms of pathogenesis, hormone receptor pathways, stem cell markers and epithelial to mesenchymal transition (EMT) drivers were asked. Kruskal-Wallis analysis followed by Dunn’s post-test was used for comparisons between groups. Statistical significance was set at p < 0.05.ResultsEpCAM-based immunoisolation positively detected CTC in high-risk endometrial cancer patients. CTC characterization indicated a remarkable plasticity phenotype defined by the expression of the EMT markers ETV5, NOTCH1, SNAI1, TGFB1, ZEB1 and ZEB2. In addition, the expression of ALDH and CD44 pointed to an association with stemness, while the expression of CTNNB1, STS, GDF15, RELA, RUNX1, BRAF and PIK3CA suggested potential therapeutic targets. We further recapitulated the EMT phenotype found in endometrial CTC through the up-regulation of ETV5 in an EC cell line, and validated in an animal model of systemic dissemination the propensity of these CTC in the accomplishment of metastasis.ConclusionsOur results associate the presence of CTC with high-risk EC. Gene-expression profiling characterized a CTC-plasticity phenotype with stemness and EMT features. We finally recapitulated this CTC-phenotype by over-expressing ETV5 in the EC cell line Hec1A and demonstrated an advantage in the promotion of metastasis in an in vivo mouse model of CTC dissemination and homing.Electronic supplementary materialThe online version of this article (doi:10.1186/1476-4598-13-223) contains supplementary material, which is available to authorized users.

Inhibition on the proliferation of human endometrial cancer cells by RNAi inhibiting HMGB1 gene expression and its possible molecular mechanism

To investigate the effect of HMGB1 small interfering RNA (siRNA) on the proliferation, cell cycle and apoptosis of human endometrial cancer cell line HEC-1A, and its possible molecular mechanism. Lentivirus vector with HMGB1 shRNA was constructed and infected the endometrial cancer cell line HEC-1A. After viral infection for 72 h, real time PCR and Western blot were performed to investigate HMGB1 mRNA and protein expression. The cell proliferation was determined with methyl thiazolyl tetrazolium (MTT) method. Flow cytometry was performed to analyze the cell cycle progression of propidium iodide (PI)-stained HEC-1A cells and the apoptotic rate of annexinV/PI-stained cells. Western blot was used to detect the protein expression of AKT, pAKT and CyclinD1. Lentivirus vector with HMGB1 shRNA inhibited the mRNA (P<0.05) and protein (P<0.01) expression of HMGB1 in the cell line HEC-1A. The MTT assay demonstrated that HMGB1 knockdown significantly reduced the cell proliferation. FCM results showed that HMGB1 knockdown significantly resulted in the disruption of the cell cycle at G0/G1 phase and the induction of apoptosis. The apoptotic rate was (17.89±0.23)%, (4.69±0.20)% and (4.62±0.17)% in the HMGB1 knockdown group, the blank group and the negative group respectively. There was significance difference between the 3 groups (P<0.01). The protein expressions of pAKT and cyclinD1 were down-regulated after the HMGB1 knockdown for 72 h. Knockdown of HMGB1 expression can significantly inhibit the proliferation and induce the cell cycle arrest and apoptosis in the endometrial cancer cell line HEC-1A. PI3K/ AKT pathway and down-regulation of the protein expression of cyclinD1 may be involved in its therapeutic mechanism.

Suppression of lymph node and lung metastases of endometrial cancer by muscle‐mediated expression of soluble vascular endothelial growth factor receptor‐3

Lymph node metastasis is the most important prognostic factor of endometrial cancer. However, effective therapy has not been established against lymph node metastasis. In this study, we explored the efficacy of gene therapy targeting lymph node metastasis of endometrial cancer by suppressing the action of vascular endothelial growth factor (VEGF)-C through soluble VEGF receptor-3 (sVEGFR-3) expression. For this purpose, we first conducted a model experiment by introducing sVEGFR-3 cDNA into an endometrial cancer cell line HEC1A and established HEC1A/sVEGFR-3 cell line with high sVEGFR-3 expression. The conditioned medium of HEC1A/sVEGFR-3 cells inhibited lymphatic endothelial cell growth in vitro, and sVEGFR-3 expression in HEC1A cells suppressed in vivo lymph node and lung metastases without inhibiting the growth of a subcutaneously inoculated tumor. To validate the therapeutic efficacy, adeno-associated virus vectors encoding sVEGFR-3 were injected into the skeletal muscle of mice with lymph node metastasis. Lymph node and lung metastases of HEC1A cells were completely suppressed by the muscle-mediated expression of sVEGFR-3 using adeno-associated virus vectors. These results suggest the possibility of gene therapy against lymph node and lung metastases of endometrial cancer by using muscle-mediated expression of sVEGFR-3.

Regulatory role of osteopontin in malignant transformation of endometrial cancer

Osteopontin (OPN) involves in the tumor-promoting or metastasis in human endometrial cancer. Depletion of OPN gene expression in endometrial cancer cells was significantly decreased in cell viability and the cells undergo apoptotic cell death. The status of OPN in THESC, RL95, Hec1A and Ishikawa cell lines were analyzed by RT-PCR and western blot. After OPN-siRNA transfection, mRNA and protein expression levels of OPN were determined in Hec1A and Ishikawa cells. Cell proliferation and cell cycle distribution were observed by MTT and flow cytometry analysis. DNA fragmentation assay was used to measure cell apoptosis. Cell migration was assessed by wound healing assay. Depletion of OPN gene expression in endometrial cancer cell lines (Hec1A and Ishikawa cells) reproducibly changed their ability of proliferation. Concomitant changes were seen in the expression of OPN binding cell surface receptors, cell cycle-regulatory genes, cell invasion and colony formation nature of the tumor cells. Decreased colonizing potential in the absence of OPN was reversed in the presence of recombinant OPN. Inhibition of anchorage-independent growth was observed in the presence of metabolic inhibitors of the PI3K, Src and integrin signaling cascades, which was ameliorated in the presence of exogenously added OPN. Our result showed the role of OPN in endometrial cancer, in particular on the malignancy-promoting aspects of OPN that may pave way for new approaches to the clinical management of endometrial cancer.

MicroRNA-200b Is Overexpressed in Endometrial Adenocarcinomas and EnhancesMMP2Activity by DownregulatingTIMP2in Human Endometrial Cancer Cell Line HEC-1A Cells

MicroRNAs (miRNAs) play important roles in tumorigenesis and metastasis. In this study, we investigated miR-200b expression in endometrial adenocarcinomas and normal adjacent tissues and found that miR-200b is more highly expressed in cancer tissues than in normal adjacent tissues. A novel target of miR-200b, tissue inhibitor of metalloproteinase 2 (TIMP2), was predicted using a bioinformatics approach and was confirmed in human endometrial cancer cell line HEC-1A cells by luciferase assay, quantitative real-time polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assay. We found that miR-200b repressed TIMP2 expression at both the messenger RNA and protein levels, although a family member, miR-200a, had no such effect. Using reverse gelatin zymography, we showed that miR-200b enhances matrix metallopeptidase 2 (MMP2) activity by downregulating TIMP2 expression in HEC-1A cells. These data suggest that miR-200b may play an important role in the metastasis of endometrial adenocarcinomas.