Endometrial carcinoma: molecular alterations involved in tumor development and progression

PTEN as a Prognostic/Predictive Biomarker in Cancer: An Unfulfilled Promise?

Identifying putative biomarkers of clinical outcomes in cancer is crucial for successful enrichment, and for the selection of patients who are the most likely to benefit from a specific therapeutic approach. Indeed, current research in personalized cancer therapy focuses on the possibility of identifying biomarkers that predict prognosis, sensitivity or resistance to therapies. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene that regulates several crucial cell functions such as proliferation, survival, genomic stability and cell motility through both enzymatic and non-enzymatic activities and phosphatidylinositol 3-kinase (PI3K)-dependent and -independent mechanisms. Despite its undisputed role as a tumor suppressor, assessment of PTEN status in sporadic human tumors has yet to provide clinically robust prognostic, predictive or therapeutic information. This is possibly due to the exceptionally complex regulation of PTEN function, which involves genetic, transcriptional, post-transcriptional and post-translational events. This review shows a brief summary of the regulation and function of PTEN and discusses its controversial aspects as a prognostic/predictive biomarker.

Oncogenic role of ABHD5 in endometrial cancer

Background

Abhydrolase domain containing 5 (ABHD5) functions as a tumor suppressor in colorectal and prostate cancers. The aim of this study was to investigate the roles of ABHD5 in endometrial cancer.

Materials and methods

ABHD5 expression was detected in clinical samples by immunohistochemical staining. Cell proliferation and invasion were evaluated with the Cell Counting Kit-8 and Transwell assay, respectively. Western blotting was performed to analyze protein expression. Glucose uptake was assessed by 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxyglucose. Lactate production was detected by a lactate assay kit.

Results

In the present study, ABHD5 was overexpressed in endometrial cancer tissues, and its expression was closely correlated with the International Federation of Gynecology and Obstetrics (FIGO) stage and lymph node metastasis. In addition, we observed that the knockdown of ABHD5 inhibited cell proliferation, invasion, glucose uptake and lactate production in HEC-1A cells, which expressed high levels of ABHD5. Conversely, the opposite effects were observed when ABHD5 was ectopically expressed in Ishikawa cells, which had low levels of ABHD5. Furthermore, the changes in glycolysis regulators (enolase 1 [ENO1], glucose transporter 1 [GLUT1] and lactate dehydrogenase A [LDHA]) and epithelial-to-mesenchymal transition-related proteins (E-cadherin and Snail) in HEC-1A cells with ABHD5 knockdown were consistent with the effects of ABHD5 on glycolysis and cell invasion. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was increased, while the phosphorylated AKT (p-AKT) was decreased when ABHD5 was downregulated. Notably, treatment with the allosteric AKT inhibitor MK-2206 completely abolished the effects caused by ABHD5 overexpression in Ishikawa cells. Finally, ABHD5 knockdown potently suppressed tumor growth in vivo.

Conclusion

Overall, these results suggest that ABHD5 may play an oncogenic role in endometrial cancer via the AKT pathway.

A potpourri of pathogenetic pathways in endometrial carcinoma with a focus on Lynch Syndrome

Endometrial carcinoma is the most frequently occurring female genital tract malignancy in developed nations, with a rising annual incidence. Endometrioid endometrial carcinoma (EEC), the most common histological variant, differs in morphologic and molecular characteristics from serous carcinomas but morphological distinction of high-grade EECs from serous carcinomas may prove difficult. Thus, molecular categorization of tumors may allow for better tumor classification with greater insight into the underlying biology of endometrial carcinomas with new therapeutic options. Microsatellite instability (MSI) is a commonly occurring molecular aberration in EECs and has been identified in most Lynch Syndrome (LS) associated tumors. This tumor syndrome predisposes afflicted individuals to a myriad of tumors including endometrial carcinoma. Herein, the molecular signature of endometrial tumors as well as LS, and its clinical manifestations are reviewed. Understanding of the pathogenetic pathways allows for greater comprehension of occurrences at a molecular level which are then appreciated at a cellular and tissue level, by the histopathologist. The molecular classification of endometrial tumors allows for further targeted therapeutic options for affected patients. Screening tests for patients with suspected LS enables surveillance of other tumors in the affected patient and her family with the potential to decrease morbidity and mortality. It is envisioned that this overview will allow for enhanced comprehension of genetic pathways by practicing pathologists, oncologists, gynecologists and other members of the multidisciplinary team, all of whom are involved in the management of the patient with an endometrial malignancy.

Immunohistochemical Profiles of Endometrioid Endometrial Carcinomas With and Without Metastatic Disease

A minority of endometrial carcinomas present at an advanced stage with a poor prognosis, and should be identified to individualize treatment. Immunohistochemical markers have been studied, but most have not been directly linked to metastasis. This study analyzes the immunohistochemical profile of endometrioid endometrial carcinomas (EECs) with and without metastases, and corresponding metastases. Tissue microarray slides from stage I EECs, stage III-IV EECs, and corresponding metastases were stained and scored for expression of β-catenin, E-cadherin, ER, PR, PTEN, p16, MLH1, PMS2, L1CAM, p53, p21, and MIB1. Scores were compared between primary stage I and III-IV EECs, stage III-IV EECs, and the corresponding metastases, and between intra-abdominal and distant metastases. Primary tumors with distant metastases had a significantly lower ER expression than those without metastases or with intra-abdominal metastases. Distant metastases had a significantly lower PR expression than the corresponding primary tumor and intra-abdominal metastases. In contrast, p16 and PTEN expression was significantly higher in intra-abdominal metastases compared with corresponding primary tumors. Immunohistochemistry predicts both presence and location of EEC metastases. Loss of ER and PR was related to distant spread, and increased expression of PTEN and p16 was related to intra-abdominal spread. Additional research should assess the use of these markers in the diagnostic workup as well as the possibility to target metastases through these markers.

Estrogen and insulin synergistically promote endometrial cancer progression via crosstalk between their receptor signaling pathways

Objective

Despite evidence that estrogens and insulin are involved in the development and progression of many cancers, their synergistic role in endometrial carcinoma (EC) has not been analyzed yet.

Methods

Here, we investigated how estrogens act synergistically with insulin to promote EC progression. Cell growth in vitro and in vivo, effects of estradiol and insulin on apoptosis and cell cycle distribution, and expression and activation of estrogen receptor (ER), insulin receptor (InsR), and key proteins in the PI3K and MAPK pathways were examined after combined stimulation with estradiol and insulin.

Results

Compared to EC cells treated with estradiol or insulin alone, those treated with both estradiol and insulin exhibited stronger stimulation. Estradiol significantly induced phosphorylation of InsR-β and IRS-1, whereas insulin significantly induced phosphorylation of ER-α. In addition, treatment with both insulin and estradiol together significantly increased the expression and phosphorylation of Akt, MAPK, and ERK. Notably, InsR-β inhibition had a limited effect on estradiol-dependent proliferation, cell cycle, and apoptosis, whereas ER-α inhibition had a limited insulin-dependent effect, in EC cell lines. Insulin and estradiol individually and synergistically promoted EC xenograft growth in mice.

Conclusions

Estrogen and insulin play synergistic roles in EC carcinogenesis and progression by activating InsR-β and ER-α, promoting a crosstalk between them, and thereby resulting in the activation of downstream PI3K/Akt and MAPK/ERK signaling pathways.

miR‑107‑5p promotes tumor proliferation and invasion by targeting estrogen receptor‑α in endometrial carcinoma

The aberrant expression of miR107-5p is closely related to the development of several types of human cancers. However, the role of miR-107-5p in endometrial carcinoma (EC) has not been fully confirmed. In the present study, we aimed to explore the function of miR-107-5p in EC carcinogenesis. EC samples and normal endometrial tissues were obtained by laser capture microdissection. It was determined that the expression of miR-107-5p in EC was significantly higher than that in normal endometrium, and higher miR-107-5p expression was related to advanced FIGO stages, lymph node metastasis and myometrial invasion in EC patients. Blocking miR-107-5p significantly inhibited cell proliferation, migration and invasion of EC cells in vitro and in vivo. The results of bioinformatic algorithms and luciferase reporter assays revealed that estrogen receptor α (ERα) was a direct target of miR-107-5p. miR-107-5p downregulated the expression of ERα mRNA and protein. In conclusion, our results highlighted that miR-107-5p is a novel prognostic factor that targets ERα to promote tumor proliferation and invasion of EC.

Estrogen affects the negative feedback loop of PTENP1-miR200c to inhibit PTEN expression in the development of endometrioid endometrial carcinoma

Endometrial carcinoma is one of the most common malignancies in the female reproductive system. It is well-known that estrogen plays an important role in the pathogenesis of endometrioid endometrial carcinoma (EEC), and induces the cancer suppressor gene PTEN deletion. However, how estrogen affects PTEN expression remains unknown. In the present study, we found in 40 EEC specimens, miR-200c level was higher in most cancer areas than that in the adjacent normal endometrium, while PTEN and PTENP1 were lower. Moreover, the expression of PTEN/PTENP1 and miR-200c also showed a converse relationship in EEC cell lines. In addition, we demonstrated that miR-200c bound directly to PTEN and PTENP1, and PTENP1 could reverse miR-200c inhibition function to PTEN using a dual-luciferase reporter and RNA binding protein immunoprecipitation (RIP) assays. Next, 17β-estradiol (E2) treatment could improve miR-200c and drop the PTEN level, which caused a consequential increase of the phospho-PI3K-AKT pathway genes. When we stably knocked down estrogen receptor α (ERα) expression in the EEC cell line, the effects of E2 on miR-200c and PTEN declined. In addition, it was demonstrated that E2 might modulate cell proliferation, migration and invasion relying on the expression of miR-200c. Taken together, it can be concluded that estrogen improves the miR-200c level by combining with ER, PTENP1 and PTEN could be inhibited by miR-200c, and then activate the PI3K-AKT pathway. This work provided a new mechanism of EEC development and a new potential therapeutic target.

miR‑494‑3p promotes the progression of endometrial cancer by regulating the PTEN/PI3K/AKT pathway

MicroRNAs (miRs) are essential regulators in the development and progression of cancer. The role of miR-494-3p in endometrial cancer (EC) has not yet been investigated. In the present study, the expression levels of miR‑494‑3p were significantly upregulated in EC tissues compared with adjacent normal tissues. Furthermore, upregulation of miR‑494‑3p in patients with EC indicated poorer prognosis; miR‑494‑3p overexpression significantly promoted the proliferation, migration and invasion of HHUA and JEC cells in vitro. Consistently, inhibition of miR‑494‑3p in HHUA cells significantly suppressed tumor growth in vivo in a xenograft model. Additionally, phosphatase and tensin homolog (PTEN) was revealed to be a direct target of miR‑494‑3p in EC cells. Furthermore, overexpression of miR‑494‑3p inhibited PTEN expression and consequently activated the downstream phosphoinositide 3‑kinase/protein kinase B (PI3K/AKT) signialing pathway. Restoration of PTEN or inhibition of PI3K/AKT pathway also abolished miR‑494‑3p‑mediated proliferation, migration and invasion of HHUA and JEC cells. In summary, the results of the present study revealed the importance of the miR‑494‑3p/PTEN/PI3K/AKT axis in the progression of EC, which may provide novel insight into potential therapeutic targets for the treatment of EC.

Patient-Derived Xenograft Models for Endometrial Cancer Research

Endometrial cancer (EC) is the most common malignancy of the genital tract among women in developed countries. Recently, a molecular classification of EC has been performed providing a system that, in conjunction with histological observations, reliably improves EC classification and enhances patient management. Patient-derived xenograft models (PDX) represent nowadays a promising tool for translational research, since they closely resemble patient tumour features and retain molecular and histological features. In EC, PDX models have already been used, mainly as an individualized approach to evaluate the efficacy of novel therapies and to identify treatment-response biomarkers; however, their uses in more global or holistic approaches are still missing. As a collaborative effort within the ENITEC network, here we describe one of the most extensive EC PDX cohorts developed from primary tumour and metastasis covering all EC subtypes. Our models are histologically and molecularly characterized and represent an excellent reservoir of EC tumour samples for translational research. This review compiles the information on current methods of EC PDX generation and their utility and provides new perspectives for the exploitation of these valuable tools in order to increase the success ratio for translating results to clinical practice.

Exploration of DNA methylation markers for diagnosis and prognosis of patients with endometrial cancer

The accurate diagnosis of endometrial cancer (EC) holds great promise for improving its treatment choice and prognosis prediction. This work aimed to identify diagnostic biomarkers for differentiating EC tumors from tumors in other tissues, as well as prognostic signatures for predicting survival in EC patients. We identified 48 tissue-specific markers using a cohort of genome-wide methylation data from three common gynecological tumors and their corresponding normal tissues. A diagnostic classifier was constructed based on these 48 CpG markers that could predict cancerous versus normal tissue with an overall correct rate of 98.3% in the entire repository. Fifteen CpG markers associated with the overall survival (OS) and development of EC were also identified based on the methylation patterns of the EC samples. A prognostic model that aggregated these prognostic CpG markers was established and shown to have a higher discriminative ability to distinguish EC patients with an elevated risk of mortality than the FIGO staging system and several other clinical prognostic variables. This study presents the utility of DNA methylation in identifying biomarkers for the diagnosis and prognosis of EC and will help improve our understanding of the underlying mechanisms involved in the development of EC.

Establishment of a nine-gene prognostic model for predicting overall survival of patients with endometrial carcinoma

Endometrial carcinoma (EC) is the most common malignant tumor of the female genital tract in developed countries. The prognosis of early stage EC is favorable, but a subset faces high risk of cancer progression or recurrence. EC has a poor prognosis upon progression to advanced or metastatic stages. Therefore, our goal is to build a robust prognostic model for predicting overall survival (OS) in EC patients. In this study, 1571 genes were identified as being associated with OS based on genomewide expression profiles using a training dataset. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that these genes were involved in various cancer-related signaling pathways. Nine signature genes were further selected using stepwise selection, and their potential role in the development of EC was demonstrated by performing differential expression analysis between EC and normal uterine tissues. A prognostic model that aggregated these nine signature genes was ultimately established and effectively divided EC patients into two risk groups. OS for patients in the high-risk group was significantly poorer compared with that of the low-risk group. This nine-gene model was subsequently validated and evaluated using the TCGA dataset and shown to have a high discriminating power to distinguish EC patients with an elevated risk of mortality based on the FIGO staging system and other prognostic factors. This study provides a novel prognostic model for the identification of EC patients with elevated risk of mortality and will help to improve our understanding of the underlying mechanisms involved in prognostic EC factors.

The Rho GTPase Rnd1 inhibits epithelial-mesenchymal transition in hepatocellular carcinoma and is a favorable anti-metastasis target

Rnd1, a member of Rho GTPases, was found to be downregulated in human malignancies and downregulation of Rnd1 promotes tumor invasion via various mechanisms. However, the role of Rnd1 in hepatocellular carcinoma (HCC) progression remains unclear. In this study, our results demonstrated that Rnd1 was downregulated in HCC cells and in human HCC tissues. Low expression of Rnd1 was associated with aggressive clinic-pathologic characteristics, such as vascular invasion, and poor prognosis in patients who underwent curative surgery for HCC. Overexpression of Rnd1-suppressed cell growth, migration, invasion, and EMT processes in vitro and in vivo. Furthermore, Rnd1 blocked HCC progression by restricting EMT process through inhibition of the Raf/MEK/ERK cascade, and this was correlated with a reduction in RhoA activity. Combination of Rnd1 overexpression with sorafenib, a Raf signaling pathway inhibitor, showed a more potent inhibition on HCC metastasis. Moreover, epigenetic inhibitors (5-Aza and SAHA) increased the expression of Rnd1, and potentiated sorafenib-induced toxicity in HCC cells. In a conclusion, Rnd1-suppressed EMT-mediated metastasis of HCC by reducing the activity of the RhoA/Raf/MEK/ERK signaling pathway, functioning as a favorable anti-metastasis target for HCC patients. Rnd1 overexpression in combination with sorafenib may result in enhanced anti-metastasis efficacy in HCC.

Abnormal Expression of PICT-1 and Its Codon 389 Polymorphism Is a Risk Factor for Human Endometrial Cancer

OBJECTIVE

The protein interacting with carboxyl terminus-1 (PICT-1) gene has been implicated as a tumor suppressor gene, and its alterations have been reported in several cancers. This study investigated the association of PICT-1 alterations with endometrial carcinogenesis.

METHODS

We analyzed the entire coding region of the PICT-1 gene using polymerase chain reaction-single-strand conformation polymorphism and DNA sequencing to examine PICT-1 mutations in endometrial cancer. Western blotting and immunohistochemical staining were performed to analyze the protein expression and cellular localization of PICT-1 in endometrial cancer cell lines and patient samples.

RESULTS

The codon 389 polymorphism of PICT-1 increased the risk of endometrial cancer. Interestingly, 2 of 13 endometrial cancers somatically acquired this mutation compared to normal counterparts. Immunohistochemical staining revealed lower levels of PICT-1 in samples from atypical endometrial hyperplasia and endometrial cancer tissues compared to normal endometrial tissues (p < 0.01). This decrease in PICT-1 expression was significantly correlated with histological grade and lymph node metastasis (p < 0.05).

CONCLUSIONS

The findings of this study suggest that disruption of PICT-1 protein expression and codon 389 polymorphism can contribute to the pathogenesis or neoplastic progression of endometrial cancer.

SOX17 is a tumor suppressor in endometrial cancer

β-catenin is a key regulatory factor for the Wnt signaling pathway. SOX17 is an important β-catenin inhibitor, while MAML3 is a co-activator of β-catenin-mediated transcription. Out of 120 endometrial cancer (EC) patients, we found that those with tumors expressing higher SOX17 (n=68) had longer recurrence-free survival (P=0.024), while higher MAML3 expression (n=76) was associated with shorter recurrence-free survival (P=0.022). Immunohistochemical and immunoprecipitation analyses revealed that SOX17 and MAML3 co-localized in EC cell nuclei, and the MAML3 C-terminal region was necessary for SOX17 binding. SOX17 regulated MAML3 transcription via binding to the MAML3 promoter, decreasing Wnt pathway protein expression and suppressing EC cell growth and colony formation in vitro. In nude mice, SOX17 over-expression inhibited tumor growth, and co-inhibition or co-overexpression of SOX17 and MAML3 rescued this response. Our results suggest that decreasing SOX17 levels may promote EC development and progression, and that by downregulating MAML3 expression and Wnt signaling, SOX17 acts as a tumor suppressor that may improve outcome in patients with EC.

EFEMP1 is repressed by estrogen and inhibits the epithelial-mesenchymal transition via Wnt/β-catenin signaling in endometrial carcinoma

Epidermal growth factor-containing fibulin-like extracellular matrix protein 1 (EFEMP1) acted as a tumor suppressor in endometrial carcinoma (EC). However, the correlation between EFEMP1 and estrogen is unknown. Here, we reported that the expression of EFEMP1 was conversely associated with ERα in endometrial carcinoma tissues. In endometrial carcinoma cells, estrogen/ERα signaling significantly suppressed the expression of EFEMP1. Moreover, chromatin immunoprecipitation (CHIP) and dual-luciferase reporter assays demonstrate that estrogen/ERα bound to the estrogen response element (ERE) located in EFEMP1 promoter and repressed its expression. Besides, in vitro and in vivo, EFEMP1 could remarkably suppress the expression of epithelial-mesenchymal transition (EMT) markers such as Vimentin, Snail and the Wnt/β-catenin target genes like Cyclin-D1 and c-Myc, which could be restored when EFEMP1 was silenced. In addition, XAV93920 (the inhibitor of the Wnt/β-catenin pathway) blocked and LiCl (the activator of the Wnt/β-catenin pathway) enhanced the effect of EFEMP1 on EMT. In conclusion, we demonstrated that estrogen/ERα signal suppresses EFEMP1. Besides, EFEMP1 inhibits EMT via interfering the Wnt/β-catenin signaling.

Advances in endometrial cancer protein biomarkers for use in the clinic

INTRODUCTION

Endometrial cancer (EC) is the fourth most common cancer in women in developed countries. The identification of sensitive and specific biomarkers to improve early detection of EC is crucial for an appropriate management of this disease, in which 30% of patients are diagnosed only at advanced stages, which is associated with high levels of morbidity and mortality. Despite major efforts and investments made to identify EC biomarkers, no protein has yet reached the stage of clinical application. Areas covered: This review gathers the numerous candidate biomarkers for EC diagnosis proposed in proteomic studies published from 1978 to 2017. Additionally, we summarize limitations associated with the proteomic technologies and study designs employed in those articles. Finally, we address new perspectives in EC biomarker research, including the comprehensive knowledge of previously suggested candidate biomarkers in conjunction with novel mass spectrometry-based proteomic technologies with enhanced sensitivity and specificity not yet applied to EC studies and a directed clinical perspective in the study design. Expert commentary: These ingredients could be the recipe to accelerate the application of protein biomarkers in the clinic.

The role of pathology in the management of patients with endometrial carcinoma

Pathology plays a critical role in every step in the management of endometrial carcinoma patients. In this review, we describe the state of the art of pathological examination, including examination of endometrium biopsy; intra-operative evaluation with gross examination and frozen section; and grossing of hysterectomy specimen and its histological and immunohistochemistry study. The main pathologic findings in each step are described, as well as limitations and difficulties that may ensue. We highlight the important pathologic parameters that determine treatment options and prognosis of endometrial cancer patients.

Mixed endometrial carcinomas with a "low-grade serous"-like component: a clinicopathologic, immunohistochemical, and molecular genetic study

Recently, we reported 2 mixed endometrioid endometrial carcinomas with a "low-grade serous"-like component, which does not fit into any of the 4 molecular groups described by The Cancer Genome Atlas. To understand the nature of these tumors, we have done an immunohistochemical and molecular genetic study of these 2 cases and added a third case. Immunoreactivity for p53, ER, Ki67, WT1, MLH1, PMS2, MSH2, and MSH6 was assessed. Targeted next-generation sequencing for somatic mutations, including genes commonly implicated in carcinogenesis including TP53, KRAS, and PIK3CA, and Sanger sequencing for PTEN and POLE were also performed. All patients were nulliparous and had morbid obesity. Their tumors showed a micropapillary component that resembled that of ovarian low-grade serous carcinoma and merged with villoglandular endometrioid carcinoma. The invasive tumor glands exhibited a microcystic, elongated, or fragmented pattern and contained psammoma bodies. Two tumors showed aberrant p53 expression, and all 3 were positive for ER. All showed KRAS mutations, and TP53 mutations were found in 2 cases. One patient developed peritoneal carcinomatosis, one patient is alive with disease, and another died of a brain tumor. The third patient, whose tumor was confined to the uterus (stage IA), is alive without evidence of disease, but she has been followed for only 6 months. Mixed endometrial carcinomas with a "low-grade" serous-like component exhibit a morphologic spectrum of endometrioid and serous differentiation with microcystic, elongated, or fragmented features; ER expression; KRAS and TP53 mutations; and aggressive behavior.

Bioluminescence Imaging to Monitor the Effects of the Hsp90 Inhibitor NVP-AUY922 on NF-κB Pathway in Endometrial Cancer

PURPOSE

In this study, we first aimed to evaluate the effects in vitro and in vivo, of the Hsp90 inhibitor NVP-AUY922, in endometrial cancer (EC). We also aimed to track nuclear factor kappa B (NF-κB) signalling, a key pathway involved in endometrial carcinogenesis and to check whether NVP-AUY922 treatment modulates it both in vitro and in vivo.

PROCEDURES

I n vitro effects of NVP-AUY922 on EC cell growth and the signalling pathways were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), clonogenic assays, Western Blot and luciferase assay. NVP-AUY922 effect on Ishikawa (IK) xenograft growth was evaluated in vivo, and NF-κB activity was monitored using bioluminescence imaging.

RESULTS

NVP-AUY922 inhibited the growth of three endometrial cell lines tested in vitro. In vivo, NVP-AUY922 reduced tumour growth of 47 % (p = 0.042) compared to control condition. Moreover, the bioluminescence signal of the tumours harbouring IK NF-κB-LUC cells was significantly reduced in NVP-AUY922-treated animals compared to untreated ones.

CONCLUSIONS

NVP-AUY922 reduced EC tumour growth and NF-κB signalling both in vitro and in vivo. As therapeutic resistance of EC remains a challenge for oncologists nowadays, we think that NVP-AUY922 represents a valid alternative to conventional chemotherapy, and we believe that this approach for assessing and tracking the activation of NF-κB pathway may be of therapeutic benefit.

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 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.

A Smad3-PTEN regulatory loop controls proliferation and apoptotic responses to TGF-β in mouse endometrium

The TGF-β/Smad and the PI3K/AKT signaling pathways are important regulators of proliferation and apoptosis, and their alterations lead to cancer development. TGF-β acts as a tumor suppressor in premalignant cells, but it is a tumor promoter for cancerous cells. Such dichotomous actions are dictated by different cellular contexts. Here, we have unveiled a PTEN-Smad3 regulatory loop that provides a new insight in the complex cross talk between TGF-β/Smad and PI3K/AKT signaling pathways. We demonstrate that TGF-β triggers apoptosis of wild-type polarized endometrial epithelial cells by a Smad3-dependent activation of PTEN transcription, which results in the inhibition of PI3K/AKT signaling pathway. We show that specific Smad3 knockdown or knockout reduces basal and TGF-β-induced PTEN expression in endometrial cells, resulting in a blockade of TGF-β-induced apoptosis and an enhancement of cell proliferation. Likewise Smad3 deletion, PTEN knockout prevents TGF-β-induced apoptosis and increases cell proliferation by increasing PI3K/AKT/mTOR signaling. In summary, our results demonstrate that Smad3-PTEN signaling axis determine cellular responses to TGF-β.

RIZ1 is regulated by estrogen and suppresses tumor progression in endometrial cancer

Endometrial cancer (EC) is the estrogen-dependent gynecologic malignancy, however the molecular mechanism involved in the development and progression of EC remain unclear. The aim of this study was to investigate the role of RIZ1 in EC. Immunohistochemical analysis revealed that RIZ1was decreased in EC than in normal endometrium. Lower RIZ1 level was correlated with high-grade carcinoma (p = 0.048) and positive expression of ERα (p = 0.004). In EC cells, estrogen could down regulated the expression of RIZ1, however, ICI182,780 could up regulated the expression of RIZ1. Besides, in vitro and in vivo, RIZ1 could remarkably suppress tumor proliferation, metastasis and invasion. Our data support that RIZ1 was a novel tumor suppressor and could provide a potential therapeutic target in human EC.

Molecular profiles of benign and (pre)malignant endometrial lesions

Endometrial carcinomas are histologically classified as endometrioid, assumed to originate from hyperplastic endometrium, or non-endometrioid carcinomas, assumed to originate from atrophic endometrium. However, both on a histological and a molecular level there are indications that there are more carcinoma types and carcinogenetic pathways. This study aims to analyze endometrial carcinogenesis on a molecular level. The presence of known KRAS, PIK3CA, AKT1, CTNNB1, BRAF, EGFR and NRAS mutations was studied in proliferative, atrophic and hyperplastic endometrium, endometrioid and serous carcinomas, and the endometrium next to these carcinomas, using single molecule Molecular Inversion Probes. Mutations were found in 9 (15%) of the 62 non atypical, and in 6 (18%) of the 34 atypical hyperplasia cases. In comparison, mutations were found in 1 (3%) of the simple, and 8 (30%) of the 27 complex hyperplasia cases. In 12/22 (55%) endometrioid carcinomas, a mutation was found. The KRAS gene was most often mutated in carcinomas next to hyperplastic endometrium, whereas PIK3CA and CTNNB1 mutations were found in endometrioid carcinomas with adjacent atrophic endometrium. Complex hyperplasia rather than atypical hyperplasia appears to be the most important lesion in the carcinogenesis of endometrioid carcinomas, and KRAS, PIK3CA and CTNNB1 mutations appear to play an important role in this process. Carcinogenesis of endometrioid carcinomas next to hyperplasia seems to be different to that of those next to atrophia. The value of these findings in managing endometrial hyperplasia and carcinoma should be studied.

A Wnt Pathway Activator Induces Apoptosis and Cell Death in Mouse Monocytic Leukemia Cells

A Wnt agonist, 2-amino-4-[3,4-(methylenedioxy)benzylamino]-6-(3-methoxyphenyl) pyrimidine, is a cell-permeable pyrimidine compound that has been shown to mimic the effect of Wnt. In this study, leukemic mouse cell lines, RAW 264.7 and J774.1, were incubated with the Wnt agonist. The Wnt agonist showed cell death in the concentration of 1-10 μM. The Wnt agonist did not show inhibition of GSK-3β activity but induced β-catenin accumulation in the nucleus. The Wnt agonist showed caspase-independent cell death, but no further involvement in cell death ER stress signaling. Here we discuss the possible mechanism of Wnt agonist-induced apoptotic cell death in RAW 264.7 cells.

The enigmatic role of RUNX1 in female-related cancers - current knowledge & future perspectives

Historically associated with the aetiology of human leukaemia, the runt-related transcription factor 1 (RUNX1) gene has in recent years reared its head in an assortment of epithelial cancers. This review discusses the state-of-the-art knowledge of the enigmatic role played by RUNX1 in female-related cancers of the breast, the uterus and the ovary. The weight of evidence accumulated so far is indicative of a very context-dependent role, as either an oncogene or a tumour suppressor. This is corroborated by high-throughput sequencing endeavours which report different genetic alterations affecting the gene, including amplification, deep deletion and mutations. Herein, we attempt to dissect that contextual role by firstly giving an overview of what is currently known about RUNX1 function in these specific tumour types, and secondly by delving into connections between this transcription factor and the physiology of these female tissues. In doing so, RUNX1 emerges not only as a gene involved in female sex development but also as a crucial mediator of female hormone signalling. In view of RUNX1 now being listed as a driver gene, we believe that greater knowledge of the mechanisms underlying its functional dualism in epithelial cancers is worthy of further investigation.

The clinical significance of DJ-1 and HE4 in patients with endometrial cancer

BACKGROUND

The non-invasive diagnostic approach for early detection of endometrial cancer (EC) remains limited. To date, human epididymis protein 4 (HE4) has been intensively studied but its diagnostic is controversial in EC. DJ-1 is an oncoprotein secreted by cancer cells, recently identified as a potential diagnostic biomarker for breast cancer, melanoma, and pancreatic cancer. The aim of this study was to compare the diagnostic performances of DJ-1 and HE4 measured in EC patients and healthy controls (HC).

METHODS

Forty-five patients (63.9±12.0 years) with EC and 29 (63.2±13.3 years) HC were enrolled. Serum concentrations of DJ-1 and HE4 were measured using ELISA kits developed by R&D (Minneapolis, USA) and Fujirebio Diagnostic (Malvern, PA, USA), respectively. Differences between EC patients and HC were assessed by Mann-Whitney test and associations were tested by Spearman's correlation. The diagnostic performance was assessed using receiver operating characteristics (ROC) curves analysis.

RESULTS

Serum DJ-1 concentrations were found to be higher in EC patients than in HC (9533.6 vs 1988.5 pg/mL; P<.0001). The area under the ROC curve (ROC-AUC) was 0.95 (P<.0001). At the cut-off of 3654 pg/mL, the sensitivity and specificity were 0.89 and 0.90, respectively. HE4 serum levels were higher in EC patients than in HC (75.3 vs 56.2 pmol/L; P=.019), with an AUC of 0.66 (P=.020). The AUC obtained by the combination of the two markers resulted 0.96 (P<.0001).

CONCLUSION

These results suggest that increased serum DJ-1 levels are associated with EC and that this biomarker may be potentially useful for diagnosing EC.

Chromatin remodelling and DNA repair genes are frequently mutated in endometrioid endometrial carcinoma

In developed countries, endometrial carcinoma is the most common cancer that affects the female genital tract. Endometrial carcinoma is divided into two main histological types, type I or endometrioid and type II or non-endometrioid, each of which have characteristic, although not exclusive, molecular alterations and mutational profiles. Nevertheless, information about the implication and relevance of some of these genes in this disease is lacking. We sought here to identify new recurrently mutated genes in endometrioid cancers that play a role in tumourigenesis and that influence the clinical outcome. We focused on low-grade, non-ultramutated tumours as these tumours have a worse prognosis than the ultramutated POLE-positive endometrioid endometrial carcinomas (EECs). We performed exome-sequencing of 11 EECs with matched normal tissue and subsequently validated 15 candidate genes in 76 samples. For the first time, we show that mutations in chromatin remodelling-related genes (KMT2D, KMT2C, SETD1B and BCOR) and in DNA-repair-related genes (BRCA1, BRCA2, RAD50 and CHD4) are frequent in this subtype of endometrial cancer. The alterations to these genes occurred with frequencies ranging from 35.5% for KMT2D to 10.5% for BRCA1 and BCOR, with some showing a tendency toward co-occurrence (RAD50-KMT2D and RAD50-SETD1B). All these genes harboured specific mutational hotspots. In addition, the mutational status of KMT2C, KMT2D and SETD1B helps to predict the degree of myometrial invasion, a critical prognostic feature. These results highlight the possible implication of these genes in this disease, creating opportunities for new therapeutic approaches.

Pathology of Endometrial Carcinoma

On a clinicopathological and molecular level, two distinctive types of endometrial carcinoma, type I and type II, can be distinguished. Endometrioid carcinoma, the typical type I carcinoma, seems to develop through an estrogen-driven "adenoma carcinoma" pathway from atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia (AEH/EIN). It is associated with elevated serum estrogen and high body mass index and expresses estrogen and progesterone receptors. They are mostly low grade and show a favorable prognosis. A subset progresses into high-grade carcinoma which is accompanied by loss of receptor expression and accumulation of TP53 mutations and behaves poorly. Other frequently altered genes in type I carcinomas are K-Ras, PTEN, and ß-catenin. Another frequent feature of type I carcinomas is microsatellite instability mainly caused by methylation of the MLH1 promoter. In contrast, the typical type II carcinoma, serous carcinoma, is not estrogen related since it usually occurs in a small uterus with atrophic endometrium. It is often associated with a flat putative precursor lesion called serous endometrial intraepithelial carcinoma (SEIC). The molecular pathogenesis of serous carcinoma seems to be driven by TP53 mutations, which are present in SEIC. Other molecular changes in serous carcinoma detectable by immunohistochemistry involve cyclin E and p16. Since many of the aforementioned molecular changes can be demonstrated by immunohistochemistry, they are useful ancillary diagnostic tools and may further contribute to a future molecular classification of endometrial carcinoma as recently suggested based on The Cancer Genome Atlas (TCGA) data.

Genetic analysis of uterine aspirates improves the diagnostic value and captures the intra-tumor heterogeneity of endometrial cancers

Endometrial cancer is the most common cancer of the female genital tract in developed countries. Although the majority of endometrial cancers are diagnosed at early stages and the 5-year overall survival is around 80%, early detection of these tumors is crucial to improve the survival of patients given that the advanced tumors are associated with a poor outcome. Furthermore, correct assessment of the pre-clinical diagnosis is decisive to guide the surgical treatment and management of the patient. In this sense, the potential of targeted genetic sequencing of uterine aspirates has been assessed as a pre-operative tool to obtain reliable information regarding the mutational profile of a given tumor, even in samples that are not histologically classifiable. A total of 83 paired samples were sequenced (uterine aspirates and hysterectomy specimens), including 62 endometrioid and non-endometrioid tumors, 10 cases of atypical hyperplasia and 11 non-cancerous endometrial disorders. Even though diagnosing endometrial cancer based exclusively on genetic alterations is currently unfeasible, mutations were mainly found in uterine aspirates from malignant disorders, suggesting its potential in the near future for supporting the standard histologic diagnosis. Moreover, this approach provides the first evidence of the high intra-tumor genetic heterogeneity associated with endometrial cancer, evident when multiple regions of tumors are analyzed from an individual hysterectomy. Notably, the genetic analysis of uterine aspirates captures this heterogeneity, solving the potential problem of incomplete genetic characterization when a single tumor biopsy is analyzed.

Molecular approaches for classifying endometrial carcinoma

Endometrial carcinoma is the most common cancer of the female genital tract. This review article discusses the usefulness of molecular techniques to classify endometrial carcinoma. Any proposal for molecular classification of neoplasms should integrate morphological features of the tumors. For that reason, we start with the current histological classification of endometrial carcinoma, by discussing the correlation between genotype and phenotype, and the most significant recent improvements. Then, we comment on some of the possible flaws of this classification, by discussing also the value of molecular pathology in improving them, including interobserver variation in pathologic interpretation of high grade tumors. Third, we discuss the importance of applying TCGA molecular approach to clinical practice. We also comment on the impact of intratumor heterogeneity in classification, and finally, we will discuss briefly, the usefulness of TCGA classification in tailoring immunotherapy in endometrial cancer patients. We suggest combining pathologic classification and the surrogate TCGA molecular classification for high-grade endometrial carcinomas, as an option to improve assessment of prognosis.

MicroRNA-93 Promotes Epithelial-Mesenchymal Transition of Endometrial Carcinoma Cells

MicroRNA-93, derived from a paralog (miR-106b-25) of the miR-17-92 cluster, is involved in the tumorigenesis and progression of many cancers such as breast, colorectal, hepatocellular, lung, ovarian, and pancreatic cancer. However, the role of miR-93 in endometrial carcinoma and the potential molecular mechanisms involved remain unknown. Our results showed that miR-93 was overexpressed in endometrial carcinoma tissues than normal endometrial tissues. The endometrial carcinoma cell lines HEC-1B and Ishikawa were transfected with miR-93-5P, after which cell migration and invasion ability and the expression of relevant molecules were detected. MiR-93 overexpression promoted cell migration and invasion, and downregulated E-cadherin expression while increasing N-cadherin expression. Dual-luciferase reporter assay showed that miR-93 may directly bind to the 3' untranslated region of forkhead box A1 (FOXA1); furthermore, miR-93 overexpression downregulated FOXA1 expression while miR-93 inhibitor transfection upregulated FOXA1 expression at both mRNA and protein level. In addition, transfection with the most effective FOXA1 small interfering RNA promoted both endometrial cancer cell migration and invasion, and downregulated E-cadherin expression while upregulating N-cadherin expression. Therefore, we suggest that miR-93 may promote the process of epithelial-mesenchymal transition in endometrial carcinoma cells by targeting FOXA1.

Repressed PKCδ activation in glycodelin-expressing cells mediates resistance to phorbol ester and TGFβ

Glycodelin is a glycoprotein mainly expressed in well-differentiated epithelial cells in reproductive tissues. In normal secretory endometrium, the expression of glycodelin is abundant and regulated by progesterone. In hormone-related cancers glycodelin expression is associated with well-differentiated tumors. We have previously found that glycodelin drives epithelial differentiation of HEC-1B endometrial adenocarcinoma cells, resulting in reduced tumor growth in a preclinical mouse model. Here we show that glycodelin-transfected HEC-1B cells have repressed protein kinase C delta (PKCδ) activation, likely due to downregulation of PDK1, and are resistant to phenotypic change and enhanced migration induced by phorbol 12-myristate 13-acetate (PMA). In control cells, which do not express glycodelin, the effects of PMA were abolished by using PKCδ and PDK1 inhibitors, and knockdown of PKCδ, MEK1 and 2, or ERK1 and 2 by siRNAs. Similarly, transforming growth factor β (TGFβ)-induced phenotypic change was only seen in control cells, not in glycodelin-producing cells, and it was mediated by PKCδ. Taken together, these results strongly suggest that PKCδ, via MAPK pathway, is involved in the glycodelin-driven cell differentiation rendering the cells resistant to stimulation by PMA and TGFβ.

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.

ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: Diagnosis, Treatment and Follow-up

The first joint European Society for Medical Oncology (ESMO), European SocieTy for Radiotherapy & Oncology (ESTRO) and European Society of Gynaecological Oncology (ESGO) consensus conference on endometrial cancer was held on 11-13 December 2014 in Milan, Italy, and comprised a multidisciplinary panel of 40 leading experts in the management of endometrial cancer. Before the conference, the expert panel prepared three clinically-relevant questions about endometrial cancer relating to the following four areas: prevention and screening, surgery, adjuvant treatment and advanced and recurrent disease. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, the panel developed recommendations for each specific question and a consensus was reached. Results of this consensus conference, together with a summary of evidence supporting each recommendation, are detailed in this article. All participants have approved this final article.

Endometrial Carcinoma: Role of Current and Emerging Biomarkers in Resolving Persistent Clinical Dilemmas

OBJECTIVES

Type II and other high-grade endometrial carcinomas may challenge conventional treatment due to recurrence and metastatic spread and therefore are a persistent clinical dilemma. Effective targeted therapy for these is a goal for clinicians and researchers alike.

METHODS

An extensive review of the literature has been performed for obtaining an in-depth understanding of the clinicopathological characteristics, etiologic factors, and molecular profile of these subsets of endometrial carcinoma. Progress made with current and emerging biomarkers for prognosis assessment and therapeutic targeting has been summarized.

RESULTS

There has been a significant increase in research on potential biomarkers of endometrial cancer, and beneficial targeted therapies have been identified.

CONCLUSIONS

Clinical trials are leading the charge for substantial gains toward personalized treatment of aggressive endometrial carcinoma subtypes.

Co-expression of galectin-3 and CRIP-1 in endometrial cancer: prognostic value and patient survival

Endometrial cancer is the sixth most common cancer in women. Galectin-3 (GAL-3) and CRIP-1 are multifunctional proteins which seem to be involved in many neoplasias. This study aims to point out correlations between clinicopathological findings and endometrial cancer patient survival to GAL-3 and CRIP-1 expression in order to enfold their diagnostic/prognostic potential. Tissues from 46 patients diagnosed with endometrial cancer were studied by immunohistochemistry, using monoclonal antibodies for GAL-3 and CRIP-1, and expression levels were correlated with clinicopathological findings and survival. Analysis was performed at single protein level or as co-expression. High expression of GAL-3 and CRIP-1 was independently associated with tumor depth and histological grade, respectively. Also, there was a significant correlation between high co-expression of the two proteins and the histological grade (aOR 2.66), the tumor depth (aOR 0.32) and the histological type (aOR 1.32), but not with the patients' age. Moreover, high expression of both proteins was observed in patients with shorter survival times. Interestingly, the co-expression of the two proteins exhibited some degree of monotony (Spearman's ρ = 0.768), indicating a common molecular pathway. This study provides evidence for a prognostic clinical potential of the combined study of GAL-3 and CRIP-1 in endometrial cancer. These factors are poorly studied in endometrium, and their role in the carcinogenetic process and on effective therapy awaits further elucidation.

ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: diagnosis, treatment and follow-up

The first joint European Society for Medical Oncology (ESMO), European SocieTy for Radiotherapy & Oncology (ESTRO) and European Society of Gynaecological Oncology (ESGO) consensus conference on endometrial cancer was held on 11-13 December 2014 in Milan, Italy, and comprised a multidisciplinary panel of 40 leading experts in the management of endometrial cancer. Before the conference, the expert panel prepared three clinically relevant questions about endometrial cancer relating to the following four areas: prevention and screening, surgery, adjuvant treatment and advanced and recurrent disease. All relevant scientific literature, as identified by the experts, was reviewed in advance. During the consensus conference, the panel developed recommendations for each specific question and a consensus was reached. Results of this consensus conference, together with a summary of evidence supporting each recommendation, are detailed in this article. All participants have approved this final article.

Molecular biology of gynecological cancer

Cancer is a pathological condition in which the balance between cell growth and death is disordered. Various molecules have been reported to be involved in the oncogenic process of invasion, metastasis and resistance to treatment. An exponential growth in the collection of genomic and proteomic data in the past 20 years has provided major advances in understanding the molecular mechanisms of human cancer, which has been applied to diagnostic and treatment strategies. Targeted therapies have been developed and adopted, particularly for advanced, refractory or recurrent cancers, depending on individual molecular profiles. The aim of the present review is to provide a report of the current literature regarding the molecular biology of gynecological cancers.

LncRNA-GAS5 induces PTEN expression through inhibiting miR-103 in endometrial cancer cells

BACKGROUND

Growth arrest-specific 5 (GAS5) was reported to be implicated and aberrantly express in multiple cancers. However, the expression and mechanism of action of GAS5 were largely poor understood in endometrial carcinoma.

RESULTS

According to the result of real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and flow cytometry analysis, we identified that GAS5 was down-regulated in endometrial cancer cells and stimulated the apoptosis of endometrial cancer cells. To investigate the expression of GAS5, PTEN and miR-103, RT-PCR was performed. And we found that the expression of PTEN was up-regulated when endometrial cancer cells overexpressed GAS5. The prediction of bioinformatics online revealed that GAS5 could bind to miR-103, which was further found to be regulated by GAS5. Finally, we found that miR-103 mimic could decrease the mRNA and protein levels of PTEN through luciferase reporter assay and western blotting, and GAS5 plasmid may reverse this regulation effect in endometrial cancer cells.

CONCLUSION

In summary, we demonstrate that GAS5 acts as an tumor suppressor lncRNA in endometrial cancer. Through inhibiting the expression of miR-103, GAS5 significantly enhanced the expression of PTEN to promote cancer cell apoptosis, and, thus, could be an important mediator in the pathogenesis of endometrial cancer.

Modal variety of microsatellite instability in human endometrial carcinomas

PURPOSE

Microsatellite instability (MSI) in human endometrial cancer (EC) was analysed using a unique fluorescent technique. MSI is associated with various human neoplasms. However, the reported frequency of MSI differs widely in each malignancy. Methodological difficulties have in fact been pointed out in its assay techniques.

METHODS

We previously established a sensitive fluorescent technique in which the major methodological problems are overcome. Application of this technique has revealed two distinct modes of microsatellite alterations, i.e. Type A and Type B. In the present study, we have applied this technique to 94 ECs.

RESULTS

Significant microsatellite alterations were observed in 38 (40.4%) tumours of the panel. The two modes, Type A and Type B, were indeed observed in this malignancy. More importantly, we found that the modes more closely correlated with the molecular and clinicopathological backgrounds of the tumours than the established and widely used MSI grades, MSI-H and MSI-L. Type B MSI widely correlated with family history of hereditary non-polyposis colorectal cancer-associated cancers, whereas MSI-H only did with that of colorectal cancer. Furthermore, mutation in the KRAS oncogene, which has been regarded as generally infrequent in microsatellite-unstable tumours, was clearly associated with Type A MSI.

CONCLUSIONS

Our observations may suggest a biological relevance and a potential utility of the modal classification of MSI and, furthermore, added complexities to genomic instability underlying tumourigenesis in human endometrium.

Clinicopathological Significance and Potential Drug Target of CDKN2A/p16 in Endometrial Carcinoma

Previous studies demonstrated that the loss of function of the CDKN2A/p16/INK4A gene is mainly caused by the hypermethylation of CDKN2A, however, whether or not it is associated with the incidence and clinicopathological characteristics of endometrial carcinoma (EC) remains unclear. In this study, we conducted a meta-analysis aiming to comprehensively assess the role of CDKN2A hypermethylation in the pathogenesis of EC. A detailed literature search was made to identify the related research publications. Analysis of pooled data was performed. Odds ratio (OR) was calculated and summarized. Final analysis of 638 EC patients from 12 eligible studies was performed. The results showed that CDKN2A hypermethylation was significantly higher in EC than in normal control tissue, the pooled OR from 8 studies including 400 EC patients and 131 controls, OR = 8.39 with 95% CI 4.03–17.45, test for overall effect, Z = 5.69, P < 0.00001. Further analysis showed that CDKN2A hypermethylation was not significantly associated with tumor differentiation and clinical stage status in EC patients. The results of this meta-analysis suggest that CDKN2A hypermethylation may be implicated in the pathogenesis of EC. CDKN2A hypermethylation was not significantly associated with tumor differentiation and clinical stage status in EC patients, indicating that CDKN2A hypermethylation might be early event of EC.

Hsa-microRNA-181a is a regulator of a number of cancer genes and a biomarker for endometrial carcinoma in patients: a bioinformatic and clinical study and the therapeutic implication

The aberrant expression of human microRNA-181a-1 (hsa-miR-181a) has been implicated in the pathogenesis of various cancers, serving as an oncogene or a tumor suppressor. However, the role of hsa-miR-181a in the pathogenesis of endometrial carcinoma (EC) and its clinical significance are unclear. This study aimed to search for the molecular targets of hsa-miR-181a using bioinformatic tools and then determine the expression levels of hsa-miR-181a in normal, hyperplasia, and EC samples from humans. To predict the targets of hsa-miR-181a, ten different algorithms were used, including miRanda-mirSVR, DIANA microT v5.0, miRDB, RNA22 v2, TargetMiner, TargetScan 6.2, PicTar, MicroCosm Targets v5, and miRWALK. Two algorithms, TarBase 6.0 and miRTarBase, were used to identify the validated targets of hsa-miR-181a-5p (a mature product of hsa-miR-181a), and the web-based Database for Annotation, Visualization and Integrated Discovery (DAVID) 6.7 was used to provide biological functional interpretation of the validated targets of hsa-miR-181a-5p. A total of 78 formalin-fixed, paraffin-embedded tissue specimens from 65 patients and 13 healthy subjects were collected and examined, including normal endometrium (n=13), endometrial hyperplasia (n=18), and EC (37 type I and 10 type II EC cases). Our bioinformatic studies have showed that hsa-miR-181a might regulate a large number of target genes that are important in the regulation of critical cell processes, such as cell fate, cell survival, metabolism, and cell death. To date, 313 targets of hsa-miR-181a have been validated, and 22 of these targets are cancer genes. The precision of predictions by all the algorithms for hsa-miR-181a-1’s targets was low. Many of these genes are involved in tumorigenesis of various cancers, including EC, based on the DAVID and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. In comparison with normal endometrial tissue, the expression level of hsa-miR-181a was significantly increased in type I and type II EC (P<0.05), and type II EC exhibited a significant higher expression level of hsa-miR-181a than that in type I EC (P<0.05). In addition, there was a significant increase in the expression level of hsa-miR-181a in type II EC compared with endometrial hyperplasia (P<0.05). Taken together, these results suggest that hsa-miR-181a may serve as an oncogene in endometrial tumorigenesis and that hsa-miR-181a might be used as a new biomarker in the prediction of prognosis of EC in clinical practice. More functional and mechanistic studies are needed to validate the role of hsa-miR-181a in the development, progression, and metastasis of EC.

Microarray expression profile of lncRNAs and the upregulated ASLNC04080 lncRNA in human endometrial carcinoma

Long non-coding RNAs (lncRNAs) have been recognized as a regulator of gene expression, and the deregulation of lncRNAs have been reported to be correlated with carcinogenesis and cancer progression. To explore the function of lncRNA in endometrial carcinoma, we analyzed the expression profiles of lncRNAs and coding genes in 3 paired endometrial carcinoma and adjacent non-tumor tissues, using a microarray. The results of microarray analysis indicated a significant difference in lncRNA and coding gene expression between endometrial carcinoma and their paired adjacent non-tumor tissues. A total of 53 lncRNAs (fold change >2.0, p-value <0.05) were found to be differently expressed in endometrial carcinoma compared to the normal controls. Among these ASLNC04080 was the most significantly upregulated lncRNA in microarray data, highly expressed in 22 out of 24 endometrial carcinoma tissues and HEC-1-B cell line. ASLNC04080 is 1867nt in length, consist of 6 exons, and locates at 1 p35.3(chr1: -28905061 - -28909492). In addition, 46 coding gene transcripts were differentially expressed (fold change >2.0, p-value <0.05) between endometrial carcinoma and adjacent non-tumor tissues. Pathway and gene ontology analysis demonstrated that these deregulated transcripts were involved in multiple signal pathways, biological processes, cellular components and molecular functions. Moreover, the ASLNC04080 lncRNA expression was correlated with 19 coding genes, and may contribute to endometrial carcinoma genesis and progression by co-regulating with coding gene. Expression inhibition of lncRNA ASLNC04080 in HEC-1-B cells caused repression of cell proliferation, increased cell apoptosis, and G1 phase arrest. These results suggested a potential function of ASLNC04080 in endometrial carcinoma genesis and progression.