Human Endometrial Cancer Cell Lines Research Articles

Tumor-associated macrophage-derived CXCL8 could induce ERα suppression via HOXB13 in endometrial cancer

PurposeTo elucidate the role of tumor-associated macrophage (TAM) in the loss of ERα in endometrial cancer (EC) and the underlying mechanism. Materials and methodsTissue microarrays and immunohistochemistry assays were performed using endometrial cancer tissue along with coculture, immunofluorescence, invasion assays and ChIP-qPCR using a human endometrial cancer cell line. ResultsCompared with normal tissue, an increased number of TAM was found in EC tissue (34.0 ± 2.6 vs. 8.3 ± 1.1, respectively; p < 0.001), which may downregulate ERα (27.4%, p < 0.05 for HEC-1A and 16.9%, p < 0.05 for Ishikawa) and promote EC cell invasion (1.8-fold, p < 0.001 for HEC-1A and 2.0-fold, p < 0.001 for Ishikawa). Furthermore, we found that TAM-derived CXCL8 mediated the loss of ERα and cancer invasion via HOXB13. HOXB13 was highly expressed in the ERα-negative subtype (r = −0.204, p = 0.002) and low expression of ESR1 was associated with a poor prognosis for EC patients (log-rank p < 0.05). ConclusionTAM-secreted CXCL8 downregulated the ERα expression of EC cells via HOXB13, which may be associated with cancer invasion, metastasis and poor prognosis.

Clomiphene citrate down-regulates estrogen receptor-α through the ubiquitin-proteasome pathway in a human endometrial cancer cell line

We examined how clomiphene citrate (CC) reduces estrogen receptor-α (ERα) in a human endometrial cancer cell line. Ishikawa human endometrial cancer cells were treated with ERα ligands such as 17β-estradiol (E2), CC, and the pure antiestrogen, ICI 182,780 (ICI). Thereafter, the expression levels of ERα protein and mRNA were analyzed by western blot and real-time quantitative PCR, respectively, and those of ubiquitinated ERα were analyzed by immunoprecipitation of ERα followed by immunoblotting with an anti-ubiquitin antibody. The expression levels of ERα protein after treatment with E2, CC, and ICI were significantly decreased compared to pre-treatment levels without a corresponding decrease in ERα mRNA. These ligands significantly increased the levels of ubiquitinated ERα compared to vehicle treatment. Co-treatment with the proteasome inhibitor, MG132, abrogated the decrease in ERα levels caused by treatment with the ligands only. We demonstrated, for the first time, a CC-induced decrease in ERα mediated by the ubiquitin-proteasome pathway in human endometrial cancer cells.

Phytoestrogenic activity of blackcurrant (Ribes nigrum) anthocyanins is mediated through estrogen receptor alpha.

Blackcurrants (Ribes nigrum L., Grossulariaceae) contain high amounts of anthocyanin polyphenols, which have antioxidant and anti-carcinogenic health benefits. This study analyzed the potential phytoestrogenic effects of blackcurrant extract (BCE) in breast cancer (MCF-7) and human endometrial cancer (Ishikawa) cell lines that over-express estrogen receptor alpha (ERα), as well as in immature female rats. Microarray analysis and Ingenuity® Pathway Analysis showed that BCE activated the ERα pathway, whereas quantitative-PCR confirmed that BCE and four types of anthocyanins up-regulated genes downstream of ERα. BCE (0.1-1.0 μg/mL) and anthocyanins (0.1-10 μM) induced MCF-7 cell proliferation; however, this effect was blocked by ER antagonist fulvestrant. Flow cytometry showed that anthocyanins reduced and increased the number of MCF-7 cells in the G0/G1 and G2/M phases, respectively. Anthocyanins stimulated ERα transcriptional activity in human ERα reporter assays and induced alkaline phosphatase activity in Ishikawa cells. Competition assays and in silico analysis indicated that anthocyanins bind to ERα. Finally, BCE focally induced stratification of columnar epithelial cells in the rat uterus and increased cytoplasmic mucin levels in these cells. These results suggest that blackcurrant anthocyanins act as phytoestrogens in vitro and in vivo.

Abstract LB-136: The role of ER chaperone GRP94 in endometrial cancer progression

Abstract Endometrial cancer is the most prevalent gynecologic cancer in the United States and accounts for nearly 50,000 incident cases annually. One of the most common mutations detected in the more prevalent Type 1 endometrial cancer is the loss of the tumor suppressor gene, Pten (phosphatase and tensin homolog). Pten mutations are involved in a wide variety of human cancers, including &amp;gt;60% of endometrial cancer. The glucose-regulated protein 94 (GRP94), also known as glycoprotein 96 (gp96), is a major chaperone protein in the ER. The client proteins of GPR94 include important regulators of cell growth and cell adhesion such as IGF-1, Toll-like receptors and integrins. GRP94 is known to play major roles in immune modulation. GRP94 also possesses anti-apoptotic properties. GRP94 elevation has been reported in a variety of human cancers and has been implicated in cancer development. Previously, GRP94 knockout in multiple myeloma reduced cell proliferation and survival, through inhibiting Wnt-LRP-survivin pathway. GRP94 knockout in macrophages reduced inflammatory colon tumorigenesis. On the other hand, GRP94 knockout in hepatocytes resulted in liver progenitor cell proliferation and acceleration of liver cancer, associating with repopulation of GRP94-positive hepatocytes. Therefore, the role of GRP94 in cancer appears to be context-dependent due to its multifaceted functions. Currently, little is known about GRP94 expression and function in endometrial cancer. We examined GRP94 expression in human endometrial cancer tissues and robust GRP94 expression was observed. In human endometrial cancer cell line, GRP94 knockdown by siRNA led to decreased proliferation and cell migration. To examine the requirement of GRP94 in the initiation and development of endometrial cancer, we utilized the Progesterone Receptor-Cre to specifically delete genes in the mouse endometrium. Before studying GRP94 in endometrial cancer, we first determined the effect of GRP94 depletion in normal uteri. Surprisingly, GRP94 single knockout uteri showed squamous cell metaplasia, confirmed by expression of K14 and p63, and reduction in size. Next, we created the biallelic mutant mice with concurrent deletion of Pten and Grp94 in the endometrium. We monitored the progress of endometrial cancer development, with mice bearing Pten knockout alone serving as the positive controls. As expected, Pten single knockout mice develop endometrial cancer by 4 week and initiate invasion into myometrium by 8 week. Analysis of the mice uteri indicated that GRP94 deficiency delayed the onset of endometrial cancer, associating with altered cell adhesion properties and pro-oncogenic signaling pathways. This study expands our understanding of GRP94 function in the progression of solid tumors and provides the first evidence that GRP94 could be a target for combating endometrial cancer. Citation Format: Jieli Shen, Yvonne G. Lin, Louis Dubeau, Amy S. Lee. The role of ER chaperone GRP94 in endometrial cancer progression. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-136. doi:10.1158/1538-7445.AM2015-LB-136

Abstract 4720: Protein kinase C alpha (PKCα) regulates PI3K/AKT signaling in endometrial cancer

Abstract Endometrial cancer is the most common gynecological malignancy and the fourth most common cancer in women in the United States. Although loss of PTEN and deregulation of PI3K/AKT signaling has been implicated in approximately 90% of endometrial cancer cases, understanding of the molecular etiology of the disease remains limited. Our analysis of tissue from 448 endometrial cancer patients has determined that ∼60% of human tumors show reduced expression or loss of the signal transduction molecule PKCα. Loss of this enzyme is also seen in endometrial hyperplasias arising in mouse models carrying germline mutations of PTEN (PtenΔ4-5, PtenC124R and PtenG129E) or endometrial specific deletion of PTEN (Ptenpr-/−), indicating that loss of PKCα can be an early event in development of the disease. In patients, reduced expression of PKCα correlates with markers of disease aggressiveness, such as increased myometrial invasion and lymph node involvement, supporting a tumor suppressive role for the enzyme in the endometrium. This correlation is particularly marked in endometrioid, PTEN-mutant disease, pointing to a potential link between PKCα and PI3K/AKT signaling. The role of PKCα in endometrial cancer was further examined using a panel of 17 human endometrial cancer cell lines with varying expression of the kinase. Restoration of PKCα in cell lines lacking the enzyme blocked their ability to grow in soft agarose, further supporting a tumor suppressive role of the kinase in this tissue. Stimulation of cells that express PKCα with PKC agonists reduced phosphorylation/activation of AKT and promoted loss of downstream PI3K/AKT targets such as cyclin D1 and inhibitor of DNA binding 1 (Id1). Analysis of the PKC isozyme expression profile in these cells combined with the use of selective inhibitors pointed to PKCα as the mediator of the effect. The demonstration that PKC agonists failed to inhibit AKT signaling in cell lines that lack expression of PKCα, and that expression of exogenous PKCα restored the effect, confirmed the involvement of PKCα. The inhibition of AKT by PKCα is dependent on PP2A since okadaic acid and calyculin A, but not the PHLPP1/2 inhibitors NSC117079 and NSC45586, blocked the effect, a finding consistent with the ability of PKCα to inhibit AKT activity in PTEN mutant cell lines. Taken together, our study provides evidence that 1) loss of PKCα is a common and early event in endometrial cancer; 2) PKCα plays a crucial role in regulating AKT activation and growth promoting signaling molecules in endometrial cancer, and 3) effects of PKCα on AKT in endometrial cancer are mediated by PP2A. Given the importance of PI3K/AKT in the disease, these findings highlight the potential of PKCα signaling as a potential biomarker for disease risk and as a potential therapeutic target in endometrial cancer. Supported by NIH grants CA036727, CA016056, and DK60632. Citation Format: Alice H. Hsu, Kathryn J. Curry, Kang-Sup Shim, Peter Frederick, Carl Morrison, Baojing Chen, Subodh M. Lele, Takiko Daikoku, Sudhansu K. Dey, Gustavo Leone, Adrian R. Black, Jennifer D. Black. Protein kinase C alpha (PKCα) regulates PI3K/AKT signaling in endometrial cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4720. doi:10.1158/1538-7445.AM2015-4720

Abstract 4462: The effects of NT-1044, a novel AMPK activator, on endometrial cancer cell proliferation and apoptosis

Abstract Objectives: Obesity and diabetes are associated with increased risk and worse outcomes in endometrial cancer (EC). Anti-diabetic biguanide drugs such as metformin may have anti-tumorigenic effects by behaving as AMPK activators and mTOR inhibitors. Metformin requires organic cation transporters (OCTs) for entry into cells, and NT-1044 (NovaTarg Therapeutics) is an AMPK activator designed to have greater affinity for two of these transporters, OCT1 and 3. We sought to compare the effects of NT-1044 on cell proliferation and apoptosis in human EC cell lines. Methods: Cell proliferation was assessed in two EC cell lines, ECC-1 and Ishikawa, by MTT assay after exposure to NT-1044. Apoptosis was analyzed by Annexin V-FITC assay. Cell cycle progression was evaluated by flow cytometry. Phosphorylated (phos)-S6, phos-AMPK, Cyclin D-1 and CDK-6 were evaluated by Western immunoblotting. Results: NT-1044 significantly inhibited proliferation in a dose-dependent manner in both EC cell lines after 72 hours of exposure (IC50 218 uM for ECC-1; 87 uM for Ishikawa). Treatment with NT-1044 resulted in G1 cell cycle arrest and apoptosis in both cell lines. NT-1044 increased phosphorylation of AMPK and decreased phosphorylation of S6, a key downstream target of the mTOR pathway. Expression of Cyclin-D1 and CDK-6 also decreased in a dose dependent-fashion in both cell lines. Conclusions: NT-1044 suppressed EC cell growth through G1 cell cycle arrest, inducing apoptosis, and inhibition of the mTOR pathway. More work is needed to determine if this novel biguanide will be beneficial in the treatment of women with EC, a disease strongly impacted by obesity and diabetes. Citation Format: Dario R. Roque, Weiya W. Wysham, Chunxiao Zhou, Ken Batchelor, Wendy R. Brewster, Victoria L. Bae-Jump. The effects of NT-1044, a novel AMPK activator, on endometrial cancer cell proliferation and apoptosis. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4462. doi:10.1158/1538-7445.AM2015-4462

Urokinase-type plasminogen activator resulting from endometrial carcinogenesis enhances tumor invasion and correlates with poor outcome of endometrial carcinoma patients.

The purpose of this study was to identify the dysregulated genes involved in the tumorigenesis and progression of endometrial endometrioid adenocarcinoma (EEC), and their possible mechanisms. Endometrial specimens including normal endometrial tissues, atypical endometrial hyperplasia, and EEC were analyzed. The expression profiles were compared using GeneChip Array. The gene expression levels were determined by real-time RT-PCR in the training and testing sets to correlate the clinico-pathological parameters of EEC. Immunoblotting, in vitro cell migration and invasion assays were performed in human endometrial cancer cell lines and their transfectants. In microarray analysis, seven dysregulated genes were identified. Only the levels of urokinase-type plasminogen activator (uPA) were higher in EEC with deep myometrial invasion, positive lympho-vascular space invasion, lymph node metastasis, and advanced stages. After multivariate analysis, uPA was the only independent poor prognostic factor for disease-free survival in the EEC patients (hazard ratio: 4.65, p = 0.03). uPA may enhance the migratory and invasive capabilities of endometrial tumor cells by the phosphorylation of ERK1/2, Akt and p38 molecules. uPA is a dysregulated gene involved in the tumorigenesis, bio-pathological features and outcomes of EEC. uPA may be a potential molecule and target for the detection and treatment of EEC.

MicroRNA-424 may function as a tumor suppressor in endometrial carcinoma cells by targeting E2F7.

MicroRNAs (miRNAs) are frequently dysregulated in human cancers and can act as potent oncogenes or tumor suppressor genes. Aberrant expression of miR-424 has been identified in some types of cancer, however, its expression and potential biologic role in endometrial cancer are remains to be determined. In the present study, we demonstrated that miR-424 was downregulated in human endometrial cancer and suppressed growth of the human Ishikawa and HEC-1B endometrial cancer cell lines. Bioinformatics analysis indicated that E2F7 was a putative target of miR-424. In a luciferase reporter system, we confirmed that E2F7 was a direct target gene of miR-424. Furthermore, knockdown of E2F7 inhibited Ishikawa and HEC-1B cell growth. These findings indicate that miR-424 targets the E2F7 transcript and suppresses endometrial cancer cell growth, suggesting that miR-424 has a tumor suppressive role in human endometrial cancer pathogenesis.

Effects of Intermediate-Conductance Ca(2+)-Activated K(+) Channels on Human Endometrial Carcinoma Cells.

The objective of this study was to investigate the effect of intermediate-conductance Ca(2+)-activated K(+) (KCa3.1) channels on the cell proliferation, cell cycle, apoptosis, migration, and invasion in endometrial cancer (EC) cells. Human EC cell lines HEC-1-A and Ishikawa were cultured in vitro and transfected with recombinant plasmid containing KCa3.1-targeting shRNA. RT-qPCR and Western blot were used to examine the mRNA and protein expression levels of KCa3.1 channels in transfected cells. In addition, the specific inhibitor of KCa3.1, TRAM-34, was used to examine the effect of KCa3.1 blockage on migration capacity and invasiveness of EC cells using transwell assay. Proliferation and apoptotic rates of EC cells transfected with KCa3.1 shRNA or treated with TRAM-34 were analyzed using MTT, BrdU incorporation assay, and flow cytometry. Expression of cell cycle proteins and metalloproteinase-2 (MMP-2) was evaluated by RT-qPCR and Western blotting. TRAM-34 treatment and KCa3.1 silencing using shRNA dramatically suppressed both the mRNA and protein expression of KCa3.1 channels (P<0.01) compared with control groups. Blockage of KCa3.1 by TRAM-34 treatment and KCa3.1 shRNA transfection exerted inhibitory effect on cell growth of both EC cell lines, as demonstrated by increased cell population at G0-G1 phase and decreasedcell population at S phase. However, both the treatments did not result in significant changes in the apoptotic rate (P>0.05) compared to controls. Protein expressions of cyclin D1, cyclin E, and survivin were significantly decreased in the experimental groups comparing to control. We showed that TRAM-34 treatment led to significantly inhibited migration, invasion, and MMP-2 expression in HEC-1-A and Ishikawa cells, compared with the control group (P<0.01). Blockage of KCa3.1 channel activity or expression inhibits cell proliferation and cell cycle progression without inducing apoptosis in EC cells. Moreover, TRAM-34 could reduce the ability of EC cells to migrate and invade, which might be related to reduced expression of MMP-2.

Pharmacologic inhibition of ATR and ATM offers clinically important distinctions to enhancing platinum or radiation response in ovarian, endometrial, and cervical cancer cells

ObjectiveSignificant reductions in gynecologic (GYN) cancer mortality and morbidity require treatments that prevent and reverse resistance to chemotherapy and radiation. The objective of this study was to determine if pharmacologic inhibition of key DNA damage response kinases in GYN cancers would enhance cell killing by platinum-based chemotherapy and radiation. MethodsA panel of human ovarian, endometrial and cervical cancer cell lines were treated with platinum drugs or ionizing radiation (IR) along with small molecule pharmacological kinase inhibitors of Ataxia telangiectasia mutated (ATM) and ATM and Rad-3-related (ATR). ResultsPharmacologic inhibition of ATR significantly enhanced platinum drug response in all GYN cancer cell lines tested, whereas inhibition of ATM did not enhance the response to platinum drugs. Co-inhibition of ATM and ATR did not enhance platinum kill beyond that observed by inhibition of ATR alone. By contrast, inhibiting either ATR or ATM enhanced the response to IR in all GYN cancer cells, with further enhancement achieved with co-inhibition. ConclusionsThese studies highlight actionable mechanisms operative in GYN cancer cells with potential to maximize response of platinum agents and radiation in newly diagnosed as well as recurrent gynecologic cancers.

Abstract 4211: Protein kinase C alpha (PKCα) signaling in endometrial cancer

Abstract Endometrial cancer is the most common gynecological malignancy in the US and the fourth most common cancer in women. Despite its high incidence, there is limited knowledge of the molecular etiology of this disease. With obesity being a major risk factor, the incidence of endometrial cancer has been on a steady incline and is expected to become an increasing cause of cancer mortality in future years. Thus, improved understanding of endometrial tumorigenesis is of critical importance. Our analysis of human endometrial tumors identified loss of the signaling molecule PKCα in approximately 60% of endometrioid (Type I) tumors. Loss of PKCα trends with increasing tumor grade and is associated with aggressive disease features such as lymphovascular involvement and myometrial invasion, pointing to an important role for this molecule in regulating endometrial cancer progression. Inactivation of the tumor suppressor PTEN and deregulation of the PI3K/AKT pathway are key drivers of Type I endometrial cancer. Thus, mice with allele-specific knock-in of cancer-related Pten mutants (i.e., PtenΔ4-5, PtenC124R, and PtenG120E) offer unique models for the disease. Precancerous endometrial hyperplasias arising in these mice show loss of PTEN and increased AKT activity. While PKCα is expressed in the normal murine endometrial epithelium at all phases of the estrus cycle, the enzyme is uniformly lost in these precancerous lesions. Thus, disruption of PKCα signaling can occur early in endometrial tumorigenesis. In human endometrial cancer cell lines, low PKCα levels also correlate with PTEN loss; however, shRNA-mediated knockdown of PTEN in PTEN expressing cells did not affect PKCα expression indicating that downregulation of the kinase is not the direct result of changes in PTEN activity. Notably, PKC agonists suppress AKT activity in cells expressing high levels PKCα (HEC-1-A, HEC-50) but not in PKCα-low cells (Ishikawa, RL95-2). Collectively, these data suggest that, in addition to PTEN inactivation, loss of PKCα is required for full activation of the PI3K/AKT signaling pathway during endometrial carcinogenesis. Analysis of the molecular basis for loss of PKCα expression in endometrial tumors identified multiple regulatory mechanisms. PKCα protein expression in tumors generally parallels that of its mRNA and promoter activity assays point to transcriptional mechanisms for PKCα downregulation. Differential mRNA and protein stability were identified as additional levels of regulation of PKCα expression in endometrial cancer. Taken together, our findings indicate that 1) PKCα signaling regulates the PI3K/AKT pathway in the endometrial epithelium; 2) concomitant loss of PKCα and PTEN may act in a co-operative manner in regulation of endometrial turmorigenesis; and 3) loss of PKCα can occur by multiple mechanisms, as often seen with tumor suppressive molecules during neoplastic progression. Supported by NIH grants CA036727, CA016056, and DK60632. Citation Format: Alice H. Hsu, Kathryn J. Curry, Kang-Sup Shim, Peter Frederick, Carl D. Morrison, Baojing Chen, Subodh M. Lele, Gustavo Leone, Adrian R. Black, Jennifer D. Black. Protein kinase C alpha (PKCα) signaling in endometrial cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4211. doi:10.1158/1538-7445.AM2014-4211

Abstract 1078: Cancer-associated fibroblasts promote endometrial cancer cell proliferation in vitro and in vivo

Abstract Cancer-associated fibroblasts (CAFs) recently demonstrated tumor-promoting roles in various cancer types, yet their implication in endometrial cancer (EC) has not been fully explored. We isolated fibroblasts (CAFs) and its epithelial counterpart from human EC tissues using CD90- and CD326-antibodies conjugated magnetic beads, respectively. We collected CAFs secretion by concentrating spent supernatants from cells growing in media containing 2% fetal bovine serum. Both human EC cell lines and primary EC epithelial cells showed increased cell proliferation in a dose-dependent manner, following treatment with CAFs secretion. This was in contrast to the growth inhibitory effects shown with secretions from normal endometrial fibroblasts. EC cells also demonstrated increased cell motility and invasiveness in response to CAFs secretion. Using cytokine array and ELISA, we further identified several cytokines which were overexpressed in CAFs compared to normal endometrial fibroblasts: macrophage chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), growth regulated oncogene (GRO), regulated on activation, normal T cell expressed and secreted (RANTES) and vascular endothelial growth factor (VEGF). These cytokines may activate MAPK/Erk and/or PI3K/Akt pathways to promote EC cell proliferation, as shown by immunoblotting and ELISA. Indeed, CAFs-mediated EC proliferation was suppressed independently by specific inhibitors for PI3K/Akt (LY294002) and MAPK/Erk (U0126). To determine if CAFs promote EC tumor proliferation in vivo, we inoculated fluorescently labeled-epithelial cell and CAFs subcutaneously at the flank of nude mice in the ratio of 1:2 and 1:4. Tumor sizes were measured twice a week using calipers and monitored weekly using in vivo imaging. Inoculation of CAFs and normal fibroblasts alone did not induce any tumor growth; however, co-injection of EC with CAFs (1:4) showed approximately 3 times higher growth rate when compared to EC alone. More interestingly, there was no sign of tumor growth in mice inoculated with combination of EC and normal fibroblasts (1:4) at the end of experiment. Taken together, our data suggests that CAFs exert tumor-promoting effects both in vitro and in vivo partly via specific cytokines-mediated activation of MAPK/Erk and PI3K/Akt pathways. Delineating the roles of CAFs in EC tumor microenvironment may provide potential therapeutic targets for the treatment of EC. Citation Format: Ivy Chung, Kavita S. Subramaniam, Seng Tian Tham, Zahurin Mohamed, Noor Azmi Mat Adenan, Yin Ling Woo. Cancer-associated fibroblasts promote endometrial cancer cell proliferation in vitro and in vivo. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1078. doi:10.1158/1538-7445.AM2014-1078

Abstract 1312: Buformin, an anti-diabetic biguanide, inhibits proliferation, invasion and adhesion, and acts synergistically with paclitaxel in endometrial cancer cell lines

Abstract Objectives: Epidemiologic and pre-clinical studies suggest that anti-diabetic biguanide drugs, such as metformin and buformin, may have anti-tumorigenic effects and behave as chemosensitizers. Thus, we evaluated the effects of buformin alone and in combination with paclitaxel on proliferation in human endometrial cancer (EC) cell lines as well as the impact of buformin on apoptosis and adhesion/invasion. Methods: The ECC-1 and Ishikawa EC cell lines were treated with varying doses of buformin alone and in combination with paclitaxel. Cell growth was determined by MTT assay. Cell cycle progression was assessed by Cellometer. Apoptosis was evaluated by Annexin V-FITC assay. Invasion was demonstrated by transwell invasion assay. Adhesion was assessed by ELISA. Effects on AMPK and S6 expression were documented by Western blotting. Results: Buformin inhibited proliferation in a dose-dependent manner in the EC cell lines (IC50 1000 μM for ECC-1, 10μM for Ishikawa, p=0.00001-0.0010). Treatment with buformin resulted in G1 arrest in the ECC-1 cell line and G2 arrest in the Ishikawa cell line. Buformin induced apoptosis in the Ishikawa cell line, but not in the ECC-1 cell line. Treatment with buformin resulted in inhibition of adhesion (p=0.42-0.0009) and invasion (p=0.00001-0.227) in both EC cell lines. Western blotting analysis demonstrated that buformin increased phosphorylation of AMPK and decreased phosphorylation of S6. Paclitaxel inhibited proliferation in a dose-dependent manner in both cell lines with IC50 values of 0.1-0.5 nM and 1-5 nM for Ishikawa and ECC-1 cells, respectively. To assess synergy of paclitaxel and buformin, the combination index (CI) was calculated by the method of Chou and Talalay. Simultaneous exposure of cells to various doses of paclitaxel in combination with buformin (0.1-1 μM) resulted in a significant synergistic anti-proliferative effect (CI &amp;lt;1, range 0.009-0.85). Conclusions: Buformin inhibited proliferation in EC cell lines, via AMPK activation and mTOR pathway inhibition. Inhibition of adhesion/invasion was also seen with buformin. Buformin acted synergistically with paclitaxel to inhibit cell proliferation. More work is needed to determine if buformin and other biguanides alone or in combination with cytotoxic agents will be beneficial in the treatment of women with EC. Citation Format: Joshua Kilgore, Amanda Jackson, Haifeng Qiu, Chunxiao Zhou, Paola Gehrig, Victoria Bae-Jump. Buformin, an anti-diabetic biguanide, inhibits proliferation, invasion and adhesion, and acts synergistically with paclitaxel in endometrial cancer cell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1312. doi:10.1158/1538-7445.AM2014-1312

KPNA2 is overexpressed in human and mouse endometrial cancers and promotes cellular proliferation.

Endometrial cancer is the most frequently occurring malignancy of the female genital tract in Western countries. Although in many cases surgically curable, about 30% of the tumours represent an aggressive and untreatable disease. In an attempt to establish a reliable prognostic marker for endometrial carcinomas disregarding their histological diversity, we investigated the expression of KPNA2, a mediator of nucleocytoplasmic transport, and other cell proliferation-associated proteins and their correlation with cancer progression. We analysed patient tissue microarrays (TMAs) assembled from 527 endometrial cancer tissue specimens and uterus samples from a Trp53 knockout mouse model of endometrial cancer. Our data show that KPNA2 expression was significantly up-regulated in human endometrial carcinomas and associated with higher tumour grade (p = 0.026), higher FIGO stage (p = 0.027), p53 overexpression (p < 0.001), activation of the PI3K/AKT pathway, and epithelial-mesenchymal transition. Increased nuclear KPNA2 immunoreactivity was identified as a novel predictor of overall survival, independent of well-established prognostic factors in Cox regression analyses (hazard ratio 1.7, 95% CI 1.13-2.56, p = 0.01). No significant association between KPNA2 expression and endometrial cancer subtype was detected. In the mouse model, KPNA2 showed increased expression levels from precancerous (EmgD, EIC) to far-advanced invasive lesions. We further investigated the cell proliferation capacity after siRNA-mediated KPNA2 knockdown in the human endometrial cancer cell line MFE-296. KPNA2 silencing led to decreased proliferation of the cancer cells, suggesting interplay of the protein with the cell cycle. Taken together, increased expression of KPNA2 is an independent prognostic marker for poor survival. The mechanism of enhanced nucleocytoplasmic transport by KPNA2 overexpression seems a common event in aggressive cancers since we have shown a significant correlation of KPNA2 expression and tumour aggressiveness in a large variety of other solid tumour entities. Introducing KPNA2 immunohistochemistry in routine diagnostics may allow for the identification of patients who need more aggressive treatment regimens.

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.

Simvastatin, an HMG-CoA reductase inhibitor, exhibits antimetastatic and antitumorigenic effects in endometrial cancer

Objectives: Statin use has been associated with improved overall survival in women with endometrial cancer. However, whether this is due to direct biologic effects or due to overall improved health is not clear. Thus, we evaluated the effects of simvastatin on cell proliferation, apoptosis, cellular stress, and adhesion/invasion in human endometrial cancer cell lines and endometrial primary culture.

The effect of Cordyceps extract and a mixture of Ganoderma lucidum/Agaricus Blazi Murill extract on human endometrial cancer cell lines in vitro.

Endometrial carcinoma is the most common gynaecological malignancy. Nevertheless there is a lack of curative therapies, especially for patients diagnosed with late stage, recurrent or aggressive disease, who have a poor prognosis. Cordyceps Sinensis, Ganoderma lucidum and Agaricus Blazi Murill are three fungi widely used in traditional Chinese medicine, and effects as adjuvants in tumour therapy have been demonstrated. However, the function and effects of these fungi in regard to endometrial cancer are not known. Three endometrial cancer cell lines, Ishikawa, Hec-1A and AN3-CA (derived from endometrial cancers grade I, II and III, respectively), were used to determine the effect of the fungi extracts on endometrial cancer cell function and to analyze the molecular mechanism. All fungi extracts had an inhibitory effect on cell viability and proliferation most probably exerted through induction of autophagy. Our data suggest that these fungi extracts may be used as adjuvants in endometrial tumour therapy.

GH induces chemoresistance in human endometrial cancer cell lines involving ERK 1/2 and PKCdelta

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Combinatorial Therapy Using Dovitinib and ICI182.780 (Fulvestrant) Blocks Tumoral Activity of Endometrial Cancer Cells

Mutations in fibroblast growth factor receptor 2 (FGFR2) have been recently described as a molecular-specific feature in endometrial carcinomas and the presence of activated FGFR2 mutations is associated with poor prognosis. For that reason, inhibition of FGFR2 could be a therapeutic target in the treatment of endometriod carcinomas. In this work, we investigated the antitumoral activity of dovitinib (a multiple kinase inhibitor) in human endometrial cancer cell (ECC) lines. We found that dovitinib caused cell growth arrest, loss of clonogenic growth, and cell-cycle arrest in FGFR2-mutated ECCs in in vitro and in vivo experiments. Next, we investigated the mechanistic basis of dovitinib effects. We could determine that dovitinib modified expression levels of well-known key cell-cycle regulatory proteins that induce cellular senescence. To further investigate the role of dovitinib, we analyzed its effect on estrogen receptor α (ER-α) expression. Surprisingly, we discovered that dovitinib enhances ER-α expression in FGFR2-mutant ECCs. Because blocking one signaling pathway is often not sufficient to cause total tumor regression and the effectiveness of individual inhibitors is often short-lived, we examined the impact of targeting FGFR2 with dovitinib in combination with a selective ER antagonist, fulvestrant (ICI182.780). Combination of dovitinib plus ICI182.780 resulted in a significantly higher inhibition of cell growth than dovitinib treatment alone. These findings suggest that combinatory therapies using dovitinib plus ICI182.780 treatment can be truly effective in patients with endometrial carcinomas carrying FGFR2 mutations.

Forkhead-box A1 suppresses the progression of endometrial cancer via crosstalk with estrogen receptor α

Mechanisms governing the function of Forkhead-box A1 (FOXA1), a member of the FOX class of transcription factors, have been extensively studied. However, little is known about the activities and expression pattern of FOXA1 in endometrial cancer (EC). In the present study, we investigated the level of FOXA1 in multiple human EC cell lines and clinical samples by immunohistochemistry, qRT-PCR and Western blot analysis. FOXA1 overexpression was observed in estrogen receptor (ER)α-positive EC cell lines (P=0.0048). In endometrial tissues, FOXA1 was significantly upregulated in both normal endometrium and well-differentiated endometrial cancer tissues (P<0.001). Functional analyses of FOXA1 were evaluated by MTT, plate colony formation and Transwell assay. The results revealed that forced expression of FOXA1 inhibited EC cell proliferation, whereas FOXA1 depletion promoted cell viability and was associated with tumorigenesis. The nude mouse tumor xenograft assay also confirmed that ablation of FOXA1 expression promoted cell proliferation. Furthermore, we found that knockdown of FOXA1 decreased the expression of ERα, and FOXA1 interacted with this receptor in the EC cell lines. Collectively, these experiments suggest that FOXA1 is a tumor suppressor in EC and has a possible interaction with ERα.