The future therapy of endometrial cancer: microRNA's functionality, capability, and putative clinical application

Determination of endometrial cancer molecular subtypes using a whole exome-sequencing based single-method approach

AIM

Endometrial cancer (EC) is heterogeneous with respect to epidemiology, clinical course, histopathology and tumor biology. Recently, The Cancer Genome Atlas (TCGA) network has identified four molecular subtypes with distinct clinical courses by an integrated multi-omics approach. These subtypes are of critical importance in the clinical management of EC. However, determination of TCGA molecular subtypes requires a complex methodological approach that is resource intensive and difficult to implement in diagnostic routine procedures. In this context, Talhouk et al. reported the precise determination of modified subtypes based on molecular surrogates obtained by a two-method approach comprising immunohistochemistry and DNA-sequence analysis (Proactive Molecular Risk Classifier for Endometrial Cancer; ProMisE). In this study, we aimed to identify EC molecular subtypes in analogy to TCGA and ProMisE applying an innovative whole exome-sequencing (WES) based single-method approach.

METHODS

WES was performed in a cohort comprising N = 114 EC patients. WES data were analyzed using the oncology treatment decision support software MH Guide (Molecular Health, Heidelberg, Germany) and EC molecular subtypes in analogy to TCGA and ProMisE were determined. Results from both classifications were compared regarding their prognostic values using overall survival and progression-free survival analyses.

RESULTS

Applying a single-method WES-approach, EC molecular subtypes analogue to TCGA and ProMisE were identified in the study cohort. The surrogate marker-analogue classification precisely identified high-risk and low-risk EC, whereas the TCGA-analogue classification failed to obtain significant prognostic values in this regard.

CONCLUSION

Our data demonstrate that determination of EC molecular subtypes analogue to TCGA and ProMisE is feasible by using a single-method WES approach. Within our EC cohort, prognostic implications were only reliably provided by applying the surrogate marker-analogue approach. Designation of molecular subtypes in EC will be increasingly important in routine clinical practice. Thus, the single-method WES approach provides an important simple tool to tailor therapeutic decisions in EC.

Determination of the Cancer Genome Atlas (TCGA) Endometrial Cancer Molecular Subtypes Using the Variant Interpretation and Clinical Decision Support Software MH Guide

BACKGROUND

The Cancer Genome Atlas (TCGA) network (United States National Cancer Institute) identified four molecular endometrial cancer (EC) subtypes using an extensive multi-method approach. The aim of this study was to determine the four TCGA EC molecular subtypes using a single-method whole-exome sequencing (WES)-based approach provided by MH Guide (Molecular Health, Heidelberg, Germany).

METHODS

WES and clinical data of n = 232 EC patients were obtained from TCGA. The four TCGA EC molecular subtypes designated as (i) Mutated Polymerase ε (POLE), (ii) Microsatellite Instability (MSI), (iii) Copy Number (CN) low and, (iv) CN-high were determined using the MH Guide software. The prognostic value of the subtypes determined by MH Guide were compared with the TCGA classification.

RESULTS

Analysis of WES data using the MH Guide software led to the precise identification of the four EC molecular subtypes analogous to the TCGA classification. Both approaches displayed high concordance in terms of prognostic significance.

CONCLUSIONS

The multi-method-based TCGA EC molecular subtypes can reliably be reproduced by the single-method-based MH Guide approach. The easy-to-implement single-method MH Guide approach represents a promising diagnostic tool.

MicroRNA-641 Inhibits Endometrial Cancer Progression via Targeting AP1G1

MicroRNA-641 (miR-641) was significantly decreased in various cancers, but its roles in endometrial cancer (EC) remain unclear. We explored the influences of miR-641 on the EC cells. In our study, the miR-641 expression was reduced in EC cells. Overexpression of miR-641 inhibited viability and proliferation of HEC-1A and HECCL-1 cells by CCK-8 and colony formation assays. Additionally, flow cytometry revealed that overexpression of miR-641 could remarkably promote apoptosis and arrest the cell cycle at the G1 phase of HEC-1A and HECCL-1 cells. Besides, forced expression of miR-641 suppressed the migration and invasion of HEC-1A and HECCL-1 cells as evidenced by wound healing and transwell assay. Moreover, AP1G1 was confirmed as a target gene of miR-641 by StarBase prediction and DLR assay and their expressions were negatively correlated. Overexpression of AP1G1 neutralized the roles of miR-641 mimic on the viability, proliferation, apoptosis, and migration of HEC-1A and HECCL-1 cells. Our findings illustrated that miR-641 was reduced in the EC cells and AP1G1 antagonized the miR-641 mimic-induced inhibition of the EC progression in vitro. Therefore, miR-641 may emerge as an effective molecule for EC treatment.

miR-20a-5p inhibits endometrial cancer progression by targeting janus kinase 1

Endometrial cancer (EC) is a multi-factorial disease of which pathogenesis has not been fully elucidated. The function and underlying mechanism of microRNA-20a-5p (miR-20a-5p) in EC remain poorly understood. The present study aimed to analyze the association between miR-20a-5p expression and the clinicopathological characteristics of patients with EC. Whether miR-20a-5p could inhibit EC progression by targeting janus kinase 1 (Jak1) was subsequently investigated. To do so, human EC tissues and paracancerous tissues were collected from 47 patients with EC. miR-20a-5p and Jak1 mRNA and protein expression was determined by reverse transcription quantitative PCR and western blotting, respectively. Cell proliferation, invasive ability and adhesion were investigated by MTT, Matrigel invasion and cell adhesion assays, respectively. Dual luciferase reporter assay was used to verify whether miR-20a-5p could directly target Jak1. The results demonstrated that miR-20a-5p was downregulated and that Jak1 was upregulated in EC tissues compared with paracancerous tissues. In addition, miR-20a-5p expression and Jak1 expression level were negatively correlated in EC tissues. miR-20a-5p expression was also significantly associated with the depth of myometrial invasion, FIGO stage, histologic grade and lymph node metastasis in patients with EC. Furthermore, Jak1 was identified as a new direct target of miR-20a-5p, and Jak1 overexpression was demonstrated to reverse the effects of miR-20a-5p-mimic on EC cell proliferation, invasive ability and adhesion. Taken together, the results from this study revealed for the first time that miR-20a-5p expression was significantly associated with the clinicopathological characteristics of patients with EC. These findings suggested that miR-20a-5p may act as a tumor suppressor in EC, in part through decreasing Jak1 expression. miR-20a-5p and Jak1 may therefore serve as potential therapeutic targets in EC.

LncRNA TTN‑AS1 promotes endometrial cancer by sponging miR‑376a‑3p

Increasing research has demonstrated that lncRNAs participate in the development of multiple cancer types. However, the role of TTN-AS1 in endometrial cancer (EC) remains unknown. The present study aimed to explore the function of titin-antisense RNA1 (TTN-AS1) in EC progression and the underlying mechanisms. qRT-PCR was performed to assess the TTN-AS1 expression patterns in EC tissues and cell lines. Loss of function experiments were carried out to estimate the effects of TTN-AS1 on EC cell proliferation, migration and invasion. To reveal the underlying mechanisms, informatics tools were used to predict the targets. Rescue experiments were performed to investigate the TTN-AS1-regulated miR-376a-3p/pumilio homolog 2 (PUM2) axis involved. The results of the present study revealed that TTN-AS1 was highly expressed in both EC tissues and cell lines, and TTN-AS1 knockdown inhibited EC cell proliferation, migration and invasion. With respect to the mechanisms, miR-376a-3p was revealed to be targeted by TTN-AS1, and reversed the effects on EC development induced by TTN-AS1. In addition, PUM2 was positively regulated by TTN-AS1, and miR-376a-3p mediated the regulation between them. Furtherly, in vivo experiments confirmed the results. Collectively, TTN-AS1 enhanced EC cell proliferation and metastasis by targeting the miR-376a-3p/PUM2 axis, which may shed light on EC diagnosis and treatment.

Extracellular vesicle encapsulated microRNA-320a inhibits endometrial cancer by suppression of the HIF1α/VEGFA axis

Accumulating evidence indicates that cancer-associated fibroblasts (CAFs) play a crucial role in endometrial cancer (EC) pathogenesis. The present study investigated the clinical significance and biological function of extracellular vesicle (EV) encapsulated miR-320a released from CAFs in EC. EC-related microarray data was obtained from the GSE25405 database and differential analysis was performed. Expression of miR-320a in CAFs and normal endometrial fibroblasts (NFs) as well as CAF-delivered EVs was detected; also, delivery of miR-320a from CAFs to EC cells was observed. In addition we confirmed that miR-320a targets HIF1α via a dual-luciferase reporter assay. Phenotypic analysis was used to study the functional significance of EV delivered miR-320a and its downstream effects. miR-320a was found to have low expression in EC cells and tissues. CAF-secreted EVs were successfully isolated and miR-320a was found also be expressed at low levels in these EVs. Finally, we found direct transfer of CAF-secreted exosomal miR-320a to EC cells, which inhibited their proliferation. Mechanistically, we found this is due to downregulation of HIF1α by miR-320a, which led to lowered VEGFA expression in vitro. Accordingly, we overexpressed HIF1α also showed that the inhibitory effect of miR-320a overexpression in EC cells could be reversed. These results point to CAF-derived EVs carrying overexpressed miR-320a as a novel direction for therapeutic strategies for EC.

Estrogen receptor alpha activates MAPK signaling pathway to promote the development of endometrial cancer

Endometrial cancer (EC) is a common malignant tumor of the female reproductive system in the world. For most of the treated patients, although the survival rate is improved, most patients still have a poor prognosis. The pathogenesis of EC has always been a strong scientific focus, but there is no clear conclusion. Therefore, in view of modularization, this study is to conduct an in-depth analysis on the effects of estrogen receptor alpha (ERα) regarding EC. The purpose is to identify the molecular course of EC. We obtained 10 co-expression modules, in which ANO2, EMP3, and other genes are significantly differentially expressed in patients with EC. Additionally, there are active regulatory effects in dysfunction modules, thus genes such as ANO2 and EMP3 would be identified as key genes, which are associated with the development of EC. Enrichment results showed that the module genes were significantly involved in RNA splicing, covalent chromatin modification, histone modification, and organelle fission, and other biological processes, as well as significantly regulated mitogen-activated protein kinases (MAPK) signaling pathway, Endocytosis, Rap1 signaling pathway, and viral carcinogenesis, and other signaling pathways. Finally, we identified noncoding RNA pivot including FENDRR, miR-520c-3p. Besides, transcription factors pivot including NFKB1, E2F1, and RELA which significantly regulate dysfunction module genes. Overall, our work deciphered a co-expression network involving differential gene regulation in ERα-associated EC. It helps reveal the core modules and potential regulatory factors of the diseases and enhances our understanding of the pathogenesis. More importantly, we revealed that ERα activates the MAPK signaling pathway to promote the development of EC. It helps to provide a new reference for later research.

MicroRNA-320a acts as a tumor suppressor in endometrial carcinoma by targeting IGF-1R

Dysregulation of microRNAs (miRs) is implicated in the carcinogenesis of various types of malignant tumor by manipulating cell growth and apoptosis. Abnormal expression of miR‑320a is involved in tumorigenesis of many types of cancer. The potential association of miR‑320a and the possible regulatory mechanisms in endometrial carcinoma is rarely elucidated. In the present study, it was demonstrated that miR‑320a expression was decreased in endometrial carcinoma tissues and cell lines. The present results also indicated that overexpression of miR‑320a suppressed cell proliferation through inducing G2/M phrase arrest and apoptosis. Insulin‑like growth factor receptror‑1 (IGF‑1R) was verified to be the potential target of miR‑320a by computational analysis and luciferase reporter assays. In addition, overexpression of miR‑320a reduced endogenous IGF‑1R expression in cells. Furthermore, it was demonstrated that upregulation of miR‑320a inhibited phosphorylated (p)‑protein kinase B and p‑mechanistic target of rapamycin activation and promoted B cell lymphoma‑2‑associated death promoter expression. Reintroduction of IGF‑1R into miR‑320a‑overexpressed cells antagonized the impact of miR‑320a on its downstream protein, which demonstrated that the tumor suppressive role of miR‑320a in endometrial carcinoma is exerted by the signal pathway mediated by IGF‑1R. It was therefore concluded that miR‑320a served an anti‑tumor role on endometrial carcinoma through the regulation of IGF‑1R, and miR‑320a may be used as the target for the gene therapy of endometrial carcinoma.

Identification of micro-RNA expression profile related to recurrence in women with ESMO low-risk endometrial cancer

Background

Actual European pathological classification of early-stage endometrial cancer (EC) may show insufficient accuracy to precisely stratify recurrence risk, leading to potential over or under treatment. Micro-RNAs are post-transcriptional regulators involved in carcinogenic mechanisms, with some micro-RNA patterns of expression associated with EC characteristics and prognosis. We previously demonstrated that downregulation of micro-RNA-184 was associated with lymph node involvement in low-risk EC (LREC). The aim of this study was to evaluate whether micro-RNA signature in tumor tissues from LREC women can be correlated with the occurrence of recurrences.

Methods

MicroRNA expression was assessed by chip analysis and qRT-PCR in 7 formalin-fixed paraffin-embedded (FFPE) LREC primary tumors from women whose follow up showed recurrences (R+) and in 14 FFPE LREC primary tumors from women whose follow up did not show any recurrence (R−), matched for grade and age. Various statistical analyses, including enrichment analysis and a minimum p-value approach, were performed.

Results

The expression levels of micro-RNAs-184, -497-5p, and -196b-3p were significantly lower in R+ compared to R− women. Women with a micro-RNA-184 fold change < 0.083 were more likely to show recurrence (n = 6; 66%) compared to those with a micro-RNA-184 fold change > 0.083 (n = 1; 8%), p = 0.016. Women with a micro-RNA-196 fold change < 0.56 were more likely to show recurrence (n = 5; 100%) compared to those with a micro-RNA-196 fold change > 0.56 (n = 2; 13%), p = 0.001.

Conclusions

These findings confirm the great interest of micro-RNA-184 as a prognostic tool to improve the management of LREC women.

miR-27a-3p promotes the malignant phenotypes of osteosarcoma by targeting ten-eleven translocation 1

Osteosarcoma has become one of the most common primary malignant tumors affecting children and adolescents. Although increasing evidence has indicated that microRNAs (miRNAs or miRs) play important roles in the development of osteosarcoma, the expression of miR‑27a‑3p and its effects on osteosarcoma are not yet fully understood. In the present study, our data demonstrated that the expression of miR‑27a‑3p in osteosarcoma cell lines was significantly higher than that in the normal human osteoblastic cell line, hFOB 1.19 cell (P<0.01). In order to explore the role of miR‑27a‑3p in the development and progression of osteosarcoma, the expression of miR‑27a‑3p was inhibited by transfection of the MG-63 cells with miR‑27a‑3p inhibitor. The results revealed that the cell proliferative ability significantly decreased (P<0.01), the number of apoptotic cells significantly increased (P<0.01) and the number of cells passing through the Transwell membrane was significantly reduced in the group transfected with the miR‑27a‑3p inhibitor (P<0.01). At the same time, the expression of E-cadherin and α-catenin was significantly upregulated (P<0.01), while the expression of vimentin was significantly downregulated in the group transfected with the miR‑27a‑3p inhibitor (P<0.01). Our results also revealed that the mRNA expression of ten-eleven translocation 1 (TET1) in the osteosarcoma cells was significantly downregulated compared with that in the hFOB 1.19 cells (P<0.01). Luciferase reporter system analysis indicated that miR‑27a‑3p recognized the TET1 3'-UTR. The protein expression of TET1 significantly increased in the group transfected with the miR‑27a‑3p inhibitor. The results from CCK-8 assay, flow cytometric assay and Transwell invasion analysis revealed that TET1 knockdown inhibited the biological effects induced by the downregulation of miR‑27a‑3p. Taken together, the findings of this study indicate that miR‑27a‑3p is upregulated, while TET1 is downregulated in human osteosarcoma cells. miR‑27a‑3p inhibition suppresses the proliferation and invasion of osteosarcoma cells, and promotes cell apoptosis via the negative regulation of TET1. miR‑27a‑3p/TET1 may thus be a potential target for the treatment of osteosarcoma.

Epigenetics in endometrial carcinogenesis - part 2: histone modifications, chromatin remodeling and noncoding RNAs

Carcinogenesis is a multistep multifactorial process that involves the accumulation of genetic and epigenetic alterations. In the past two decades, there has been an exponential growth of knowledge establishing the importance of epigenetic changes in cancer. Our work focused on reviewing the main role of epigenetics in the pathogenesis of endometrial carcinoma, highlighting the reported results concerning each epigenetic mechanistic layer. In a previous review, we assessed DNA methylation alterations. The present review examines the contribution of histone modifications, chromatin remodeling and noncoding RNA alterations for endometrial carcinogenesis.