Enhancer of zeste homolog 2 blockade by RNA interference is implicated with inhibited proliferation, invasion and promoted apoptosis in endometrial carcinoma

SWI/SNF Antagonism of PRC2 Mediates Estrogen-Induced Progesterone Receptor Expression

Endometrial cancer (EC) is characterized by high estrogen levels unopposed by progesterone. Treatment with progestins is standard for early EC, but the response to progestins is dependent on progesterone receptor (PGR) expression. Here, we show that the expression of PGR in endometrial epithelial cells is dependent on ARID1A, a DNA-binding subunit of the SWI/SNF chromatin-remodeling complex that is commonly mutated in EC. In endometrial epithelial cells with estrogen receptor overexpression, we find that ARID1A promotes estrogen signaling and regulates common gene expression programs. Normally, endometrial epithelial cells expressing estrogen receptors respond to estrogen by upregulating the PGR. However, when ARID1A expression is lost, upregulation of PGR expression is significantly reduced. This phenomenon can also occur following the loss of the SWI/SNF subunit BRG1, suggesting a role for ARID1A- and BRG1-containing complexes in PGR regulation. We find that PGR is regulated by a bivalent promoter, which harbors both H3K4me3 and H3K27me3 histone tail modifications. H3K27me3 is deposited by EZH2, and inhibition of EZH2 in the context of ARID1A loss results in restoration of estrogen-induced PGR expression. Our results suggest a role for ARID1A deficiency in the loss of PGR in late-stage EC and a therapeutic utility for EZH2 inhibitors in this disease.

The Interplay of Tumor Stroma and Translational Factors in Endometrial Cancer

Endometrial cancer (EC) is a common gynecologic malignancy which continues to have a poor prognosis in advanced stages due to current therapeutic limitations. A significant mechanism of chemoresistance in EC has been shown to also be the enhancement of epithelial to mesenchymal transition (EMT) and the subsequent obtainment of stem cell-like characteristics of EC. Current evidence on EMT in EC however fails to explain the relationship leading to an EMT signaling enhancement. Our review therefore focuses on understanding eukaryotic translation initiation factors (eIFs) as key regulators of the translational process in enhancing EMT and subsequently impacting higher chemoresistance of EC. We identified pathways connected to the development of a microenvironment for EMT, inducers of the process specifically related to estrogen receptors as well as their interplay with eIFs. In the future, investigation elucidating the translational biology of EC in EMT may therefore focus on the signaling between protein kinase RNA-like ER kinase (PERK) and eIF2alpha as well as eIF3B.

LncRNA NEAT1 promotes endometrial cancer cell proliferation, migration and invasion by regulating the miR-144-3p/EZH2 axis

Background

Endometrial cancer (EC) is one of the most common gynaecological tumours in the worldwide. Long non-coding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) promotes cell proliferation, migration and invasion in EC cells. However, the molecular mechanisms of NEAT1 in EC have not been fully clarified. We conducted this study to reveal the function of NEAT1 in EC tissues and cell lines.

Materials and methods

Cancer and adjacent tissues were collected from EC patients. HEC-1A and Ishikawa cells were cultured in vitro. NEAT1 expression was downregulated by transfecting small hairpin RNA (shRNA) and miR-144-3p was overexpressed by transfecting miR-144-3p mimics. Cell proliferation was detected by MTT assay and colony formation assay. Cell migration and invasion abilities were assessed by transwell assay. A dual-luciferase reporter assay was used to verify the relationship among NEAT1, EZH2, and miR-144-3p. The expression level of EZH2 was measured by Western blot and qPCR.

Results

NEAT1 was highly expressed in EC tissues and cells. Knockdown of NEAT1 inhibited the proliferation, migration and invasion of EC cells. Additionally, NEAT1 acted as a ceRNA of miR-144-3p, leading to EZH2 upregulation. Overexpression of miR-144-3p suppressed the proliferation and invasion of EC cells.

Conclusions

NEAT1 promotes EC cells proliferation and invasion by regulating the miR-144-3p/EZH2 axis.

GSK343 induces autophagy and downregulates the AKT/mTOR signaling pathway in pancreatic cancer cells

Pancreatic cancer is a common malignancy that has a poor prognosis and limited therapeutic options. Enhancer of zeste homolog 2 (EZH2) serves a key role in the progression of different types of cancers. The effect of GSK343 (a competitive inhibitor of EZH2) on pancreatic cancer cells was assessed in the present study. Cell viability was evaluated using MTT and cell counting kit-8 assays in AsPC-1 and PANC-1 cells. Flow cytometry and an EdU assay were also performed to assess the effects of GSK343 on cell proliferation, apoptosis and the cell cycle. The induction of autophagy and associated molecular mechanisms were studied using fluorescence microscopy and western blot analysis. The results demonstrated that GSK343 inhibited cell viability in a dose- and time-dependent manner. Furthermore, GSK343 suppressed cell proliferation, promoted apoptosis and blocked cell cycle progression at the G1-phase. Furthermore, GSK343 induced autophagy in pancreatic cancer via the AKT/mTOR signaling pathway. In conclusion, GSK343 exhibited an anti-cancer effect on pancreatic cancer cells, downregulating the AKT/mTOR signaling pathway.

Anti-Müllerian Hormone Expression in Endometrial Cancer Tissue

Anti-Müllerian hormone (AMH) is a commonly known factor secreted by Sertoli cells, responsible for regression of the Müllerian ducts in male fetuses. AMH has also other functions in humans. In vivo and in vitro studies have shown that AMH inhibits cell cycle and induces apoptosis in cancers with AMH receptors. The aim of the study was to assess whether the tissue of pre-cancerous states of endometrium (PCS) and various histopathologic types of endometrial cancer (EC) exhibit the presence of AMH. We aimed to investigate whether the potential presence of the protein concerns menopausal women or those regularly menstruating, and whether is related to cancers with a good or a bad prognosis, as well as what other factors may influence AMH expression. The undertaken analysis was carried out on tissues retrieved from 232 women who underwent surgical treatment for PCS and EC. Tissues were prepared for immunohistochemical assessment with the use of a tissue microarrays method. AMH expression was confirmed in 23 patients with well differentiated endometrioid adenocarcinoma (G1), moderately differentiated endometrioid adenocarcinoma (G2), clear cell carcinoma (CCA) and nonatypical hyperplasia. AMH was not found in EC tissues in regularly menstruating women. An appropriately long mean period of breastfeeding in line with a prolonged period of hormonal activity had a positive effect on AMH expression. Our results may suggest that AMH is a factor which protects the organism against cancer, and should be further investigated as a potential prognosis marker and a therapeutic agent.