Assessing Estrogen-Induced Proliferative Response in an Endometrial Cancer Cell Line Using a Universally Applicable Methodological Guide

Fallopian tube epithelial cells express androgen receptor and have a distinct hormonal responsiveness when compared with endometrial epithelium

STUDY QUESTION

How does steroid receptor expression, proliferative activity and hormone responsiveness of the fallopian tube (FT) epithelium compare to that of the endometrial epithelium?

SUMMARY ANSWER

Proliferative indices, hormone receptor expression-scores and in vitro response to oestrogen and androgens of the human FT demonstrate a distinct pattern from the matched endometrium.

WHAT IS KNOWN ALREADY

The FT epithelium exists as a continuum of the endometrium, and both express steroid hormone receptors. The ovarian steroid hormones regulate cyclical proliferation and regeneration of the endometrium, but their effects on steroid hormone receptor expression and proliferation in the FT have not yet been fully elucidated.

STUDY DESIGN, SIZE, DURATION

We included women with proven fertility, undergoing hysterectomy and bilateral salpingo-oophorectomy for benign, gynaecological conditions at Liverpool Women's NHS Foundation Trust. They had no known endometrial or tubal pathology and were not on hormonal treatments for at least 3 months preceding sample collection in this prospective observational study (conducted between 2010 and 2018). A full-thickness sample of the endometrium and a sample from the FT were collected from each woman.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The differential protein and mRNA levels of steroid hormone receptors, oestrogen receptors α and β, androgen receptor (AR) and progesterone receptor (PR), and the proliferative marker (Ki67) of the endometrium and the FT tissue samples from 47 healthy women undergoing surgery (37 premenopausal and 10 postmenopausal) were investigated using immunohistochemistry and quantitative real-time PCR. The comparative responsiveness to oestrogen and androgen of the endometrium and the fimbrial end of the FT was analysed using an in vitro short-term explant culture model. The endpoints assessed in the explants were the changes in mRNA and protein levels for AR, PR and the epithelial proliferative index after 24 h treatment with oestradiol (E2) or dihydrotestosterone (DHT).

MAIN RESULTS AND THE ROLE OF CHANCE

The premenopausal endometrial functionalis glands (FG) displayed the well-known cyclic variation in cellular proliferation and steroid receptor scores. Compared with the endometrial FG, the matched FT epithelium (both fimbrial or isthmic ends) displayed a significantly lower proportion of cells expressing Ki67 (2.8% ± 2.2%, n = 18 vs 30.0% ± 26.3%, n = 16, P = 0.0018, respectively) accompanied with a significantly higher AR immunoscores (6.7 ± 2.7, n = 16 vs 0.3 ± 1.0, n = 10, P = 0.0136). The proportion of cells expressing Ki67 and the AR immunoscores of the FT epithelium correlated positively with endometrial luminal epithelium (r = 0.62, P = 0.005, and r = 0.68, P = 0.003, respectively). In vitro experiments suggested the tubal explants to be apparently less responsive to E2 yet more sensitive to DHT compared with the matched endometrium explants.

LIMITATIONS, REASONS FOR CAUTION

The short-term in vitro nature of the tissue explant cultures used in the study may not be representative of how different anatomical regions of the endometrium and FT behave in vivo. Our study included a high proportion of older premenopausal women with a regular menstrual cycle, which may therefore affect extrapolation of findings to a younger group.

WIDER IMPLICATIONS OF THE FINDINGS

Advancing our understanding of tubal and endometrial epithelial cell function has important implications for the diagnosis and treatment of diseases such as infertility, ectopic pregnancy, endometriosis and cancer.

STUDY FUNDING/COMPETING INTEREST(S)

The work included in this article was funded by Wellbeing of Women project grants RG1073 and RG2137 (D.K.H.) and Wellbeing of Women Entry-Level Scholarship ELS706 (A.M). A.M. was also supported by an NIHR ACF fellowship grant. Further support received from Liverpool Women's Hospital NHS Trust (S.M.), University of Liverpool (E.B. and A.W.). All authors declare there are no conflicts of interest.

TRIAL REGISTRATION NUMBER

N/A.

Aberrant Dyskerin Expression Is Related to Proliferation and Poor Survival in Endometrial Cancer

Simple Summary

Telomeres are the protective caps at the ends of chromosomes, and they are maintained by an enzyme called telomerase. Telomerase activity allows rapid reproduction of the cells (proliferation) of the lining of the womb (endometrium). Telomerase levels are high in cancers in general, including in endometrial cancer. Dyskerin is one of the main components of the telomerase enzyme. While the other main components of telomerase have been studied in endometrial cancer, there are no previous studies on dyskerin in the endometrium. Our study shows that dyskerin levels are significantly lower in endometrial cancer and levels are linked to the survival of women. Experimentally increasing dyskerin protein in endometrial cells in the laboratory reduces the rate of cell proliferation. Consequently, we propose that dyskerin may be a regulator of endometrial cancer cell proliferation, and further studies are required to test if it can be targeted to develop new therapies for endometrial cancer.

Abstract

Dyskerin is a core-component of the telomerase holo-enzyme, which elongates telomeres. Telomerase is involved in endometrial epithelial cell proliferation. Most endometrial cancers (ECs) have high telomerase activity; however, dyskerin expression in human healthy endometrium or in endometrial pathologies has not been investigated yet. We aimed to examine the expression, prognostic relevance, and functional role of dyskerin in human EC. Endometrial samples from a cohort of 175 women were examined with immunohistochemistry, immunoblotting, and qPCR. The EC cells were transfected with Myc-DDK-DKC1 plasmid and the effect of dyskerin overexpression on EC cell proliferation was assessed by flow cytometry. Human endometrium expresses dyskerin (DKC1) and dyskerin protein levels are significantly reduced in ECs when compared with healthy postmenopausal endometrium. Low dyskerin immunoscores were potentially associated with worse outcomes, suggesting a possible prognostic relevance. Cancer Genome Atlas (TCGA) ECs dataset (n = 589) was also interrogated. The TCGA dataset further confirmed changes in DKC1 expression in EC with prognostic significance. Transient dyskerin overexpression had a negative effect on EC cell proliferation. Our data demonstrates a role for dyskerin in normal endometrium for the first time and confirms aberrant expression with possible prognostic relevance in EC. Interventions aimed at modulating dyskerin levels may provide novel therapeutic options in EC.

Methylsulfonylmethane sensitizes endometrial cancer cells to doxorubicin

BACKGROUND

Methylsulfonylmethane (MSM) is a commonly used diet supplement believed to decrease the inflammation in joints and fastens recovery in osteoarthritis, gastric mucosal injury, or obesity-related disorders. It was also suggested that MSM might play a beneficial role in cancer treatment.

PURPOSE

So far, the MSM might have a potentially beneficial effect in endometrial cancer (EC) treatment.

STUDY DESIGN

This study evaluated the effect and usefulness of MSM in combinatory therapy with known drug doxorubicin (DOX).

METHODS

The effect of combinational treatment of MSM and DOX on the induction of apoptosis was evaluated in EC cell lines (ISHIKAWA, MFE-296, MFE-280).

RESULTS

We observed that MSM itself induces apoptosis in EC cell lines, and pre-treatment with MSM for 24 h increases the sensitivity of EC cells to DOX-induced apoptosis and DNA damage and that effect might be regulated by p42/44 (Erk1/2) MAPK and Akt (protein kinase B).

CONCLUSION

These results for the first time show that MSM might act as a sensitizer of EC cells to known drugs, for which EC cells quickly acquire resistance. Graphical abstract.

Differences in the Expression Pattern of mRNA Protein SEMA3F in Endometrial Cancer in vitro under Cisplatin Treatment

BACKGROUND

Semaphorin 3F (SEMA3F) plays a substantial role in carcinogenesis, because of its role in inducing angiogenesis, and creating a microenvironment for the developing tumor.

OBJECTIVE

The purpose of this work was to assess the impact of cisplatin, depending on the concentration and exposure time on the expression pattern of SEMA3F in an endometrial cancer cell line.

MATERIALS AND METHODS

Cultures of the Ishikawa endometrial cancer cells were incubated with cisplatin with the following concentrations: 2.5μM; 5μM; and 10μM and for the following periods of time: 12; 24; and 48 hours. Cells not incubated with the drug constituted the control in the experiment. To determine the effect of cisplatin on the expression of SEMA3F, the real-time quantitative reverse transcription reaction (RtqPCR; mRNA) was used, as well as the ELISA assay (protein). The statistical analysis was done with the admission of p<0.05.

RESULTS

The silencing of SEMA3F expression on the transcriptome and proteome levels in a culture unexposed to the effects of cisplatin in comparison to endometrial cancer cells under the influence of cisplatin (p<0.05) were noted. Along with an increase in the concentration of the drug used, the number of copies of the gene transcript, during the shortest incubation period had a gradual increase. Only for the highest concentration of the drug, substantial statistical differences in the expression of the SEMA3F protein between 24 and 48 hour incubation periods (p<0.05) were determined.

CONCLUSION

Using cisplatin in an endometrial cancer cell culture results in an increased expression of SEMA3F, which advantageously affects the normalization of the neoplastic angiogenic process and lowers the proliferation of the cells making up the mass of the tumor.

MiR-181c affects estrogen-dependent endometrial carcinoma cell growth by targeting PTEN

MicroRNAs (miRNAs), which is a type of non-coding and single-stranded small molecule RNA, bind either completely or incompletely to 3'-UTR of the target gene mRNA to inhibit mRNA translation or degradation. In our study, we aimed to explore the roles and mechanisms of miR-181c in the apoptosis of RL95-2 human endometrial carcinoma cells. Cell activity and apoptosis were detected by cell counting Kit-8 (CCK-8) assay and flow cytometry (FCM), respectively. Related mRNAs and proteins expression was determined by quantitative real-time reverse transcription PCR (qRT-PCR) and western blot assays, respectively. The binding capacity of PTEN-3'-UTR and miR-181c was assessed by luciferase reporter assay. The obtained results suggested that E2 evidently increased the cell activity of RL95-2 cells. In addition, miR-181c inhibitor suppressed the cell viability and enhanced the apoptosis capacity of E2-induced RL95-2 cells and distinctly reduced the miR-181c expression. We also found that miR-181c could bind to PTEN-3'-UTR and miR-181c inhibitor up-regulated the expression level of PTEN in E2-induced RL95-2 cells. Besides, overexpression of PTEN markedly promoted the apoptosis of E2-induced RL95-2 cells through regulating the Bax and Bcl-2 expression, and modulated the expression of AKT pathway, p53 and Cyclin D. In conclusion, our findings revealed that miR-181c affected the estrogen-dependent endometrial carcinoma cell growth by targeting PTEN. The potential effects of miR-181c on the apoptosis of E2-induced RL95-2 cells suggest that miR-181c could be an effective target for endometrial carcinoma therapies.

Telomerase and Telomeres in Endometrial Cancer

Telomeres at the termini of human chromosomes are shortened with each round of cell division due to the “end replication problem” as well as oxidative stress. During carcinogenesis, cells acquire or retain mechanisms to maintain telomeres to avoid initiation of cellular senescence or apoptosis and halting cell division by critically short telomeres. The unique reverse transcriptase enzyme complex, telomerase, catalyzes the maintenance of telomeres but most human somatic cells do not have sufficient telomerase activity to prevent telomere shortening. Tissues with high and prolonged replicative potential demonstrate adequate cellular telomerase activity to prevent telomere erosion, and high telomerase activity appears to be a critical feature of most (80–90%) epithelial cancers, including endometrial cancer. Endometrial cancers regress in response to progesterone which is frequently used to treat advanced endometrial cancer. Endometrial telomerase is inhibited by progestogens and deciphering telomere and telomerase biology in endometrial cancer is therefore important, as targeting telomerase (a downstream target of progestogens) in endometrial cancer may provide novel and more effective therapeutic avenues. This review aims to examine the available evidence for the role and importance of telomere and telomerase biology in endometrial cancer.

High AGR2 protein is a feature of low grade endometrial cancer cells

BACKGROUND

Biomarkers for identification of endometrial cancers (ECs) with high risk of recurrence are required to reduce the rising EC-related mortality. AGR2 is a prognostic marker in several hormonally-regulated cancers.

AIM

To assess the utility of AGR2 as a prognostic marker in EC.

METHODS

AGR2 immunoexpression was evaluated in 163 human endometrial samples. Change in AGR2 mRNA levels in response to oestrogen and dihydrotestosterone was studied in vitro.

RESULTS

Upregulation of AGR2 (protein and mRNA) was seen in low grade EC, compared to the postmenopausal endometrium (P = 0.013) and to the high-grade EC (P < 0.0001). Elevated AGR2 protein expression-scores were associated with a high expression of estrogen alpha (ERα), progesterone, androgen receptors and early clinical stages. Metastatic lesions maintained higher AGR2 expression relative to matched-primary tumors. High-AGR2 protein levels were associated with better overall survival (P = 0.02) in all ECs, but in highly-ERα-expressing ECs, AGR2 associated with unfavourable patient outcome. Androgen through its receptor, downregulated AGR2 mRNA in the Ishikawa cells.

CONCLUSIONS

AGR2 is overexpressed in low grade ECs and positively associated with hormone receptors. The association between high AGR2 and progressive disease within the high-ERα-expressing ECs suggests that in this group of patients, AGR2 might be a potential biomarker of poor prognosis.

ALCAM shedding at the invasive front of the tumor is a marker of myometrial infiltration and promotes invasion in endometrioid endometrial cancer

Endometrial cancer (EC) is the sixth deadliest cancer in women. The depth of myometrial invasion is one of the most important prognostic factors, being directly associated with tumor recurrence and mortality. In this study, ALCAM, a previously described marker of EC recurrence, was studied by immunohistochemistry at the superficial and the invasive tumor areas from 116 EC patients with different degree of myometrial invasion and related to a set of relevant epithelial and mesenchymal markers. ALCAM expression presented a heterogeneous functionality depending on its localization, it correlated with epithelial markers (E-cadherin/β-catenin) at the superficial area, and with mesenchymal markers at the invasive front (COX-2, SNAIL, ETV5, and MMP-9). At the invasive front, ALCAM-negativity was an independent marker of myometrial invasion. This negativity, together with an increase of soluble ALCAM in uterine aspirates from patients with an invasive EC, and its positive correlation with MMP-9 levels, suggested that ALCAM shedding by MMP-9 occurs at the invasive front. In vivo and in vitro models of invasive EC were generated by ETV5-overexpression. In those, we demonstrated that ALCAM shedding was related to a more invasive pattern and that full-ALCAM recovery reverted most of the ETV5-cells mesenchymal abilities, partially through a p-ERK dependent-manner.