Long Non-Coding RNAs in Endometrial Carcinoma

Construction and Validation of a Prognostic Risk Prediction Model for Lactate Metabolism-Related lncRNA in Endometrial Cancer

Endometrial cancer (EC) is a common group of malignant epithelial tumors that mainly occur in the female endometrium. Lactate is a key regulator of signal pathways in normal and malignant tissues. However, there is still no research on lactate metabolism-related lncRNA in EC. Here, we intended to establish a prognostic risk model for EC based on lactate metabolism-related lncRNA to forecast the prognosis of EC patients. First, we found that 38 lactate metabolism-associated lncRNAs were significantly overall survival through univariate Cox regression analysis. Using minimum absolute contraction and selection operator (LASSO) regression analysis and multivariate Cox regression analysis, six lactate metabolism-related lncRNAs were established as independent predictor in EC patients and were used to establish a prognostic risk signature. We next used multifactorial COX regression analysis and receiver operating characteristic (ROC) curve analysis to confirm that risk score was an independent prognostic factor of overall patient survival. The survival time of patients with EC in different high-risk populations was obviously related to clinicopathological factors. In addition, lactate metabolism-related lncRNA in high-risk population participated in multiple aspects of EC malignant progress through Gene Set Enrichment Analysis, Genomes pathway and Kyoto Encyclopedia of Genes and Gene Ontology. And risk scores were strongly associated with tumor mutation burden, immunotherapy response and microsatellite instability. Finally, we chose a lncRNA SRP14-AS1 to validate the model we have constructed. Interestingly, we observed that the expression degree of SRP14-AS1 was lower in tumor tissues of EC patients than in normal tissues, which was consistent with our findings in the TCGA database. In conclusion, our study constructed a prognostic risk model through lactate metabolism-related lncRNA and validated the model, confirming that the model can be used to predict the prognosis of EC patients and providing a molecular analysis of potential prognostic lncRNA for EC.

Clinical application of liquid biopsy in endometrial carcinoma

Endometrial cancer is the most common gynecological malignant tumor in women, and its morbidity and mortality have been rising in recent years. Over the past two decades, the diagnosis, prognosis, and therapeutic strategies for endometrial cancer have not significantly improved, and reliable biomarkers for detecting and monitoring EC recurrence and progression remain limited. Tumor genome analysis identified molecular alterations related to the growth and progression of endometrial cancer, but these data are incomplete. Recently, through extensive exploration of liquid biopsy, it has been determined that circulating tumor cells and circulating tumor DNA can lay a foundation for real-time and non-invasive monitoring of tumors and provide novel insights into cancer evolution, invasion, and metastasis. Hence, this review aimed to analyze the value of liquid biopsy in endometrial cancer screening, early diagnosis, treatment response, and prognosis monitoring in order to prolong the survival time of EC patients.

lncRNA ENST00000585827 Contributes to the Progression of Endometrial Carcinoma via Regulating miR-424/E2F6/E2F7 Axis

Endometrial cancer (EC) ranks fourth among the most common gynecologic malignancies. Despite advances in medical technology, the pathogenesis is still unclear. Numerous reports have identified the involvement of lncRNA in the malignant progression of endometrial cancer. The aim of the study was to investigate the expression level of lncRNA ENST00000585827 (lncRNA E27) in endometrial cancer and the molecular mechanism that regulates the development of endometrial cancer. Combined with the results of the previous study, PCR analysis confirmed that lncRNA E27 was significantly upregulated in endometrial cancer cell lines. The results of CCK-8, wound healing assay, and transwell experiments showed that lncRNA E27 could significantly inhibit cell proliferation, migration, and invasion. Flow cytometry results confirmed that lncRNA E27 could promote apoptosis. Furthermore, based on bioinformatics predictions, dual-luciferase assay and RT-qPCR analysis confirmed that miR-424, as its downstream molecule, competitively regulates the expression of E2F6/E2F7. Rescue experiments further supported that lncRNA E27 inhibited proliferation, migration, invasion, and promoted apoptosis of endometrial cancer through miR-424/E2F6/E2F7 signaling axis. Conclusively, our findings revealed the role of lncRNA E27 in regulating the miR-424/E2F6/E2F7 signaling axis during EC progression, opening up new strategies for the treatment of endometrial cancer.

LncRNA HOTAIR regulates cell invasion and migration in endometriosis through miR-519b-3p/PRRG4 pathway

Endometriosis is a common benign disease in gynecology and has malignant biological behaviors, such as hyperplasia, invasion, metastasis, and recurrence. However, the pathogenesis of endometriosis remains unclear. The present study aimed to investigate whether LncRNA HOTAIR regulates cell invasion and migration in endometriosis by regulating the miR-519b-3p/PRRG4 pathway. The qRT-PCR results showed that the average relative expression of LncRNA HOTAIR was much higher in ectopic endometrial tissues than in eutopic endometrial tissues. Scratch and transwell assays showed that the cell migration and invasion ability of LncRNA HOTAIR overexpression group was significantly higher than those in the control group. Conversely, the LncRNA HOTAIR knockdown group showed the opposite results. Bioinformatics analysis suggested that the downstream target genes of LncRNA HOTAIR were miR-519b-3p and Prrg4. Knockdown of LncRNA HOTAIR can reduce the up-regulation of Prrg4 by miR-519b-3p and then inhibit the invasion and migration ability of endometrial stromal cells. In Conclusion, LncRNA HOTAIR can regulate the ability of invasion and migration of endometrial stromal cells, and its mechanism is proved by regulating the miR-519b-3p/PRRG4 pathway.

LncRNA TUG1 promotes the migration and invasion in type I endometrial carcinoma cells by regulating E-N cadherin switch

OBJECTIVE

Accumulating evidence has demonstrated that lncRNA Taurine-upregulated gene 1 (TUG1) plays an important role in regulation of cell morphology, migration, proliferation and apoptosis. Our aim was to evaluate the oncogenic role of TUG1 in type I Endometrial Carcinoma (EC) and explore the precise mechanism of TUG1 involved in tumor progression.

MATERIALS AND METHODS

The GSE17025 data set was used to analyze the correlation of TUG1 expression with type I EC patients' prognosis. Furthermore, TUG1 expression profiles were measured by qRT-PCR from carcinoma tissues and adjacent nonneoplastic tissues (NNT) of 105 type I EC patients. The regulation of epithelial-mesenchymal transition (EMT) related molecules, p-AKT and AKT by TUG1 knockdown was investigated using Western blot analysis; meanwhile, the oncogenic roles of TUG1 were evaluated using cell viability and transwell migration/invasion assay in Hec-1-A and Ishikawa cell lines.

RESULTS

Firstly, we observed a significant association between higher TUG1 expression and lower survival rate in type I EC patients using the GSE17025 data set. A significant elevation of TUG1 levels was confirmed in type I EC tissues compared with NNT in the 105 type I EC patients, and high expression of TUG1 was associated with lymph vascular space invasion (LVSI) and lymph node metastasis (LNM). Subsequently, TUG1 knockdown could remarkably inhibit the Hec-1-A and Ishikawa cell invasion and migration in the functional experiment. Furthermore, our results showed that the protein levels of E-cadherin increased and N-cadherin decreased significantly, while β-catenin and Vimentin were not significantly altered upon TUG1 silencing in both Hec-1-A and Ishikawa cells. Finally, we found the p-AKT and AKT protein levels, and the rate of p-AKT/t-AKT has a tendency to be down-regulate in Hec-1-A cells, while the AKT pathway was not change significantly in Ishikawa cells after TUG1 knockdown.

CONCLUSION

Collectively, our data reveal that TUG1 might be regarded as an oncogenic molecule that promotes type I EC cells metastasis leading to tumor progression, at least partially, by regulating E-N cadherin switch and the AKT pathway.

DSCAM-AS1 Long Non-Coding RNA Exerts Oncogenic Functions in Endometrial Adenocarcinoma via Activation of a Tumor-Promoting Transcriptome Profile

Accumulating evidence suggests that lncRNA DSCAM-AS1 acts tumor-promoting in various cancer entities. In breast cancer, DSCAM-AS1 was shown to be the lncRNA being most responsive to induction by estrogen receptor α (ERα). In this study, we examined the function of DSCAM-AS1 in endometrial adenocarcinoma using in silico and different in vitro approaches. Initial analysis of open-source data revealed DSCAM-AS1 overexpression in endometrial cancer (EC) (p < 0.01) and a significant association with shorter overall survival of EC patients (HR = 1.78, p < 0.01). In EC, DSCAM-AS1 was associated with endometrial tumor promotor gene PRL and with expression of ERα and its target genes TFF1 and PGR. Silencing of this lncRNA by RNAi in two EC cell lines was more efficient in ERα-negative HEC-1B cells and reduced their growth and the expression of proliferation activators like NOTCH1, PTK2 and EGR1. DSCAM-AS1 knockdown triggered an anti-tumoral transcriptome response as revealed by Affymetrix microarray analysis, emerging from down-regulation of tumor-promoting genes and induction of tumor-suppressive networks. Finally, several genes regulated upon DSCAM-AS1 silencing in vitro were found to be inversely correlated with this lncRNA in EC tissues. This study clearly suggests an oncogenic function of DSCAM-AS1 in endometrial adenocarcinoma via activation of a tumor-promoting transcriptome profile.

Pyroptosis-related lncRNAs are potential biomarkers for predicting prognoses and immune responses in patients with UCEC

Uterine corpus endometrial carcinoma (UCEC) is a malignant disease globally, and there is no unified prognostic signature at present. In our study, two clusters were identified. Cluster 1 showed better prognosis and higher infiltration level, such as tumor microenvironment (TME), tumor mutation burden (TMB), and immune checkpoint genes expression. Gene set enrichment analysis (GSEA) indicated that some tumor-related pathways and immune-associated pathways were exposed. What is more, six pyroptosis-related long noncoding RNAs (lncRNAs) (PRLs) were applied to establish a prognostic signature through multiple Cox regression analysis. In both training and testing sets, patients with higher risk score had poorer survival than patients with low risk. The area under the curve (AUC) of receiver operating characteristic (ROC) curves performed that the survival probability was better in people with lower risk score. Mechanism analysis revealed that high risk score was correlated with reduced immune infiltration and T cells exhaustion, matching the definition of an "immune-desert" phenotype. Patients with lower risk score were characterized by higher immune checkpoint gene expression and TMB and have a sensitive response to immunotherapy and chemotherapy compared with patients with high risk score. The signature has accurate prediction ability of UCEC and is a promising therapeutic target to improve the effect of immunotherapy.

lncRNA-ZFAS1 promotes the progression of endometrial carcinoma by targeting miR-34b to regulate VEGFA expression

Zinc finger nuclear transcription factor, X-box binding 1-type containing 1 antisense RNA 1 (ZFAS1) functions as an oncogenic long noncoding RNA (lncRNA) to promote proliferation and metastasis of endometrial carcinoma cell; however, the underlying mechanism has not been fully understood. First, RT-qPCR analysis of endometrial carcinoma tissues and cells showed that ZFAS1 was enriched in endometrial carcinoma tissues and cells. miR-34b was reduced in endometrial carcinoma and suggested negative correlation with ZFAS1 in endometrial carcinoma. Second, functional assays demonstrated that siRNA-mediated silence of ZFAS1 suppressed endometrial carcinoma cell proliferation and metastasis. Third, ZFAS1 bind to miR-34b and negatively regulate expression of miR-34b in endometrial carcinoma cells. miR-34b also bind to and negatively regulate expression of vascular endothelial growth factor A (VEGFA) in endometrial carcinoma cells. Lastly, knockdown of miR-34b counteracted with the suppressive effects of ZFAS1 silence on endometrial carcinoma cell proliferation and metastasis. In conclusion, lncRNA ZFAS1 functioned as an oncogene to promote endometrial carcinoma cell proliferation and metastasis through miR-34b/VEGFA axis.

Anticancer effects of melatonin via regulating lncRNA JPX-Wnt/β-catenin signalling pathway in human osteosarcoma cells

Osteosarcoma (OS) is a type of malignant primary bone cancer, which is highly aggressive and occurs more commonly in children and adolescents. Thus, novel potential drugs and therapeutic methods are urgently needed. In the present study, we aimed to elucidate the effects and mechanism of melatonin on OS cells to provide a potential treatment strategy for OS. The cell survival rate, cell viability, proliferation, migration, invasion and metastasis were examined by trypan blue assay, MTT, colony formation, wound healing, transwell invasion and attachment/detachment assay, respectively. The expression of relevant lncRNAs in OS cells was determined by real-time qPCR analysis. The functional roles of lncRNA JPX in OS cells were further examined by gain and loss of function assays. The protein expression was measured by western blot assay. Melatonin inhibited the cell viability, proliferation, migration, invasion and metastasis of OS cells (Saos-2, MG63 and U2OS) in a dose-dependent manner. Melatonin treatment significantly downregulated the expression of lncRNA JPX in Saos-2, MG63 and U2OS cells. Overexpression of lncRNA JPX into OS cell lines elevated the cell viability and proliferation, which was accompanied by the increased metastasis. We also found that melatonin inhibited the OS progression by suppressing the expression of lncRNA JPX via regulating the Wnt/β-catenin pathway. Our results suggested that melatonin inhibited the biological functions of OS cells by repressing the expression of lncRNA JPX through regulating the Wnt/β-catenin signalling pathway, which indicated that melatonin might be applied as a potentially useful and effective natural agent in the treatment of OS.

LINC00470 Stimulates Methylation of PTEN to Facilitate the Progression of Endometrial Cancer by Recruiting DNMT3a Through MYC

OBJECTIVES

Increasing researches emphasize the importance of long non-coding RNAs (lncRNAs) in the development of endometrial cancer (EC). There is wide recognition that LINC00470 is a critical participant in the tumorigenesis of cancers such as gastric cancer and glioblastoma, but its possible effects on EC progression remain to be explored.

METHODS

We collected EC tissues and cells, where the expression of LINC00470 was determined, and followed by the Kaplan-Meier analysis of EC patient survival. We next examined the effect of LINC00470 and phosphatase and tensin homolog (PTEN) on EC cell migration, invasion, tube formation in vitro, and angiogenesis in mice xenografted with tumor after gain- or loss-of-function treatments. RNA pull-down, Co-IP, and ChIP experiments were performed to analyze the targeting relationships among LINC00470, MYC and DNMT3a.

RESULTS

LINC00470 was aberrantly upregulated in EC and its high expression correlated to prognosis of EC patients. LINC00470 promoted invasiveness, migration, and angiogenesis of EC cells, and facilitated tumorigenesis and metastasis in vivo, but those effects were reversed by up-regulating PTEN. Functionally, LINC00470 bound to MYC in EC and that LINC00470 stimulated the binding of MYC to DNMT3a, and thus recruited DNMT3a through MYC to promote PTEN methylation.

CONCLUSIONS

Our findings revealed that LINC00470 stimulated PTEN methylation to inhibit its expression by MYC-induced recruitment of DNMT3a, thus aggravating EC.

Long non-coding RNAs in endometrial physiology and pathophysiology

The endometrium is an essential component of the female uterus which provides the environment for pregnancy establishment and maintenance. Abnormalities of the endometrium not only lead to difficulties in establishing and maintaining pregnancy but also play a causative role in diseases of endometrial origin including endometriosis and endometrial cancer. Non-coding RNAs are proposed to play a role in regulating the genome in both normal endometrial physiology and pathophysiology. In this review, we first provide a general overview of non-coding RNAs and reproductive physiology of the endometrium. We then discuss the role on non-coding RNAs in normal endometrial physiology and pathophysiology of endometrial infertility. We then conclude with non-coding RNAs in the pathophysiology of endometriosis and endometrial cancer.

A Novel Prognostic Model of Endometrial Carcinoma Based on Clinical Variables and Oncogenomic Gene Signature

Due to the difficulty in predicting the prognosis of endometrial carcinoma (EC) patients by clinical variables alone, this study aims to build a new EC prognosis model integrating clinical and molecular information, so as to improve the accuracy of predicting the prognosis of EC. The clinical and gene expression data of 496 EC patients in the TCGA database were used to establish and validate this model. General Cox regression was applied to analyze clinical variables and RNAs. Elastic net-penalized Cox proportional hazard regression was employed to select the best EC prognosis-related RNAs, and ridge regression was used to construct the EC prognostic model. The predictive ability of the prognostic model was evaluated by the Kaplan-Meier curve and the area under the receiver operating characteristic curve (AUC-ROC). A clinical-RNA prognostic model integrating two clinical variables and 28 RNAs was established. The 5-year AUC of the clinical-RNA prognostic model was 0.932, which is higher than that of the clinical-alone (0.897) or RNA-alone prognostic model (0.836). This clinical-RNA prognostic model can better classify the prognosis risk of EC patients. In the training group (396 patients), the overall survival of EC patients was lower in the high-risk group than in the low-risk group [HR = 32.263, (95% CI, 7.707-135.058), P = 8e-14]. The same comparison result was also observed for the validation group. A novel EC prognosis model integrating clinical variables and RNAs was established, which can better predict the prognosis and help to improve the clinical management of EC patients.

LINC00665 enhances tumorigenicity of endometrial carcinoma by interacting with high mobility group AT-hook 1

Background

Endometrial carcinoma is a frequently diagnosed cancer among females. LncRNAs are reported to be associated with various cancers. Their biological roles in endometrial carcinoma progression is an emerging scientific area. LINC00665 can exert a significant role in many cancers. However, its potential function in endometrial carcinoma is still poorly known.

Method

qRT-PCR was carried out to test expression of LINC00665 and HMGA1. Western blot analysis was carried out to detect protein expression of HMGA1. Cell proliferation was evaluated using Cell Counting Kit-8 (CCK-8) and EdU assay. Flow cytometry assay was used to determine cell apoptosis and cell cycle. Wound healing and transwell invasion assay was carried out to test cell migration and invasion. Immunohistochemical staining and HE staining were conducted to assess Ki-67 and tumor growth respectively.

Results

Expression of LINC00665 in clinical endometrial carcinoma tissues and cells was obviously up-regulated. Loss of LINC00665 could repress endometrial carcinoma cell viability, induce cell apoptosis and block cell cycle in G1 phase. KLE and HHUA cell migration and invasion ability were depressed by LINC00665 shRNA. Decrease of LINC00665 suppressed endometrial carcinoma tumorigenicity in vivo. RIP assay proved that LINC00665 directly bound with HMGA1 protein. shRNA of HMGA1 obviously restrained endometrial carcinoma cell growth and cell invasion.

Conclusions

LINC00665 might promote endometrial carcinoma progression by positively modulating HMGA1.

The role of HOTAIR/miR-152-3p/LIN28B in regulating the progression of endometrial squamous carcinoma

INTRODUCTION

There is growing evidence that long non-coding RNAs (lncRNAs) are correlated with malignancy in the modulation of tumor progression. This study aims to investigate the effect of homeobox protein (HOX) transcript antisense RNA (HOTAIR) on the migration and invasion of ESC.

MATERIAL AND METHODS

Starbase was used to identify miRNAs with complementary base pairing with HOTAIR. RNA pull-down and qRT-PCR were employed to investigate the effect of HOTAIR on miR-152-3p. In vitro cell migration and invasion assays were performed to assess the effects of HOTAIR and miR-152-3p on ESC. Computational software, TargetScan, was then used to identify the potential target of miR-152-3p, and their relationship was verified by immunoblotting analysis, qRT-PCR and luciferase reporter assay.

RESULTS

Starbase predicted a potential miR-152-3p binding site in HOTAIR, which was validated by RNA pull-down assay. HOTAIR was negatively correlated with miR-152-3p in ESC. Moreover, HOTAIR promoted migration and invasion of ESC. The oncogenic activity of HOTAIR was partly through its negative regulation of miR-152-3p. LIN28B was identified to be a direct target of miR-152-3p. A negative correlation between LIN28B and miR-152-3p was observed in ESC. In addition, overexpression of miR-152-3p suppressed the progression of ESC by directly targeting and regulating LIN28B.

CONCLUSIONS

Our results reveal that HOTAIR may be a driver of ESC through inhibiting miR-152-3p, a tumor suppressor, suggesting that miR-152-3p may be a potential target for advanced ESC therapeutic treatment.

lncRNA RHPN1-AS1 promotes the progression of endometrial cancer through the activation of ERK/MAPK pathway

AIM

This study aimed to investigate the function of long noncoding RNA RHPN1 antisense RNA 1 (lncRNA RHPN1-AS1) in the progression of endometrial cancer (EC) and its underlying molecular mechanisms.

METHODS

The RHPN1-AS1 expression was measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) in EC tissues and cells. The cell clones, proliferation, cell cycle, apoptosis, migration and invasion in Ishikawa and HEC-1A cells were respectively measured by colony formation assay, cell counting kit-8 assay (CCK-8) assay, flow cytometry, wound healing assay and transwell assay. In addition, the protein expressions in Ishikawa and HEC-1A cells were measured using western blot and Immunofluorescence assay.

RESULTS

Our data showed the RHPN1-AS1 expression was significantly upregulated in both EC tissues and cells. The expression of RHPN1-AS1 was significantly correlated with FIGO stage, histological grade, and lymph node metastasis. Additionally, silencing RHPN1-AS1 could inhibit proliferation, cell cycle progression, migration and invasion, and also promote apoptosis in Ishikawa and HEC-1A cells. Moreover, silencing RHPN1-AS1 could markedly elevate the expressions of caspase-3 and Bax, but reduce the Bcl-2 expression in Ishikawa and HEC-1A cells. We also found that silencing RHPN1-AS1 could significantly inhibit the phosphorylation of MEK and ERK in Ishikawa and HEC-1A cells. After U0126 pretreatment, the inhibition effect of silencing RHPN1-AS1 on the phosphorylation of MEK and ERK was strengthened.

CONCLUSION

Our study demonstrated that RHPN1-AS1 could facilitate cell proliferation, migration and invasion, as well as inhibit apoptosis via activating ERK/MAPK pathway in EC.

Regulatory Networks of LncRNA MALAT-1 in Cancer

Long noncoding (lnc)RNAs are a group of RNAs with a length greater than 200 nt that do not encode a protein but play an essential role in regulating the expression of target genes in normal biological contexts as well as pathologic processes including tumorigenesis. The lncRNA metastasis-associated lung adenocarcinoma transcript (MALAT)-1 has been widely studied in cancer. In this review, we describe the known functions of MALAT-1; its mechanisms of action; and associated signaling pathways and their clinical significance in different cancers. In most malignancies, including lung, colorectal, thyroid, and other cancers, MALAT-1 functions as an oncogene and is upregulated in tumors and tumor cell lines. MALAT-1 has a distinct mechanism of action in each cancer type and is thus at the center of large gene regulatory networks. Dysregulation of MALAT-1 affects cellular processes such as alternative splicing, epithelial–mesenchymal transition, apoptosis, and autophagy, which ultimately results in the abnormal cell proliferation, invasion, and migration that characterize cancers. In other malignancies, such as glioma and endometrial carcinoma, MALAT-1 functions as a tumor suppressor and thus forms additional regulatory networks. The current evidence indicates that MALAT-1 and its associated signaling pathways can serve as diagnostic or prognostic biomarker or therapeutic target in the treatment of many cancers.

Long non-coding RNAs in prostate tumorigenesis and therapy (Review)

Prostate cancer (PCa) is one of the most frequently diagnosed malignancy. Although there have been many advances in PCa diagnosis and therapy, the concrete mechanism remains unknown. Long non-coding RNAs (lncRNAs) are novel biomarkers associated with PCa, and their dysregulated expression is closely associated with risk stratification, diagnosis and carcinogenesis. Accumulating evidence has suggested that lncRNAs play important roles in prostate tumorigenesis through relevant pathways, such as androgen receptor interaction and PI3K/Akt. The present review systematically summarized the potential clinical utility of lncRNAs and provided a novel guide for their function in PCa.

Identification of long noncoding RNA RP11-89K21.1 and RP11-357H14.17 as prognostic signature of endometrial carcinoma via integrated bioinformatics analysis

Background

Endometrial carcinoma (EC) is one of the most common malignant tumors in gynecology. The potential functions and mechanisms of long noncoding RNAs (lncRNAs) in the occurrence and progression of EC remains unclear. It’s meaningful to explore lncRNAs signature for providing prognostic value of EC.

Methods

The differentially expressed lncRNAs and their prognostic values in EC were investigated based on The Cancer Genome Atlas (TCGA) database; the transcriptional factors (TFs), the competing endogenous RNA (ceRNA) mechanism, functional regulatory network and immune infiltration of RP11-89K21.1 and RP11-357H14.17 were further explored by various bioinformatics tools and databases.

Results

We firstly identified high expression of RP11-89K21.1 and RP11-357H14.17 were closely associated with shorten overall survival (OS) and poor prognosis in patients with EC. We also elucidated the networks of transcription factor and co-expression genes associated with RP11-89K21.1 and RP11-357H14.17. Furthermore, the ceRNA network mechanism was successfully constructed through 2 lncRNAs (RP11-89K21.1 and RP11-357H14.17), 11 miRNAs and 183 mRNAs. Functional enrichment analysis revealed that the targeting genes of RP11-89K21.1 and RP11-357H14.17 were strongly associated with microRNAs in cancer, vessel development, growth regulation, growth factor and cell differentiation, and involved in pathways including pathways in cancer, microRNAs in cancer and apoptotic signaling pathway.

Conclusions

We demonstrated for the first time that RP11-89K21.1 and RP11-357H14.17 may play crucial roles in the occurrence, development and malignant biological behavior of EC, and can be regarded as potential prognostic biomarkers for EC.

Machine Learning Supports Long Noncoding RNAs as Expression Markers for Endometrial Carcinoma

Uterine corpus endometrial carcinoma (UCEC) is the second most common type of gynecological tumor. Several research studies have recently shown the potential of different ncRNAs as biomarkers for prognostics and diagnosis in different types of cancers, including UCEC. Thus, we hypothesized that long noncoding RNAs (lncRNAs) could serve as efficient factors to discriminate solid primary (TP) and normal adjacent (NT) tissues in UCEC with high accuracy. We performed an in silico differential expression analysis comparing TP and NT from a set of samples downloaded from the Cancer Genome Atlas (TCGA) database, targeting highly differentially expressed lncRNAs that could potentially serve as gene expression markers. All analyses were performed in R software. The receiver operator characteristics (ROC) analyses and both supervised and unsupervised machine learning indicated a set of 14 lncRNAs that may serve as biomarkers for UCEC. Functions and putative pathways were assessed through a coexpression network and target enrichment analysis.

LncRNA RP11-361F15.2 promotes osteosarcoma tumorigenesis by inhibiting M2-Like polarization of tumor-associated macrophages of CPEB4

Long non-coding RNAs (lncRNAs) regulates the initiation and progression of osteosarcoma (OS), specifically lncRNA RP11-361F15.2 has been shown to play prominent roles in tumorigenesis. Previously, M2-Like polarization of tumor-associated macrophages (TAMs) has been identified to play a key role in cancer migration/invasion. Hence, it is essential to understand the role of RP11-361F15.2 in tumorigenesis and its association with M2-Like polarization of TAMs. The results indicate that RP11-361F15.2 is significantly increased in OS tissues, and its expression is positively correlated with cytoplasmic polyadenylation element binding protein 4 (CPEB4) expression and negatively associated with miR-30c-5p expression. Further, overexpression of RP11-361F15.2 increased OS cell migration/invasion and M2-Like polarization of TAMs in vitro, as well as promoted xenograft tumor growth in vivo. Mechanistically, luciferase reporter assays indicated that RP11-361F15.2 upregulated CPEB4 expression by competitively binding to miR-30c-5p. Further, we have identified that RP11-361F15.2 promotes CPEB4-mediated tumorigenesis and M2-Like polarization of TAMs through miR-30c-5p in OS. We also identified that RP11-361F15.2 acts as competitive endogenous RNA (ceRNA) against miR-30c-5p thereby binding and activating CPEB4. This RP11-361F15.2/miR-30c-5p/CPEB4 loop could be used as a potential therapeutic strategy for the treatment of OS.

Long non-coding RNA steroid receptor activator promotes the progression of endometrial cancer via Wnt/ β-catenin signaling pathway

Rationale: Steroid receptor activator (SRA), a long non-coding RNA, serves as a critical regulator of gynecologic cancer. The objective of this study was to determine biological function and clinical significance of SRA expression in endometrial cancer.

Method: We investigated whether SRA was involved in the development of endometrial cancer via binding to eukaryotic translation initiation factor 4E-binding protein 1 (EIF4E-BP1) as a transcription factor to enhance Wnt/ β-catenin signaling pathway.

Results: Expression levels of SRA were upregulated in endometrial cancer tissues compared to those in adjacent control tissues. We also found high expression of SRA in EC cells. The relationship between SRA and EIF4E-BP1 was corroborated by transfection of a luciferase reporter plasmid. In addition, SRA knockdown inhibited the expression of EIF4E-BP1 known to play a critical role in the control of protein synthesis, cell growth, and cell survival, thus promoting tumourigenesis and epithelial-mesenchymal transition (EMT) important for cell motility and metastasis. Consistently, immunostaining and western blotting analysis showed that expression levels of β-catenin and 4EBP1 in the nucleus were significantly decreased by SRA knockdown but increased by SRA over-expression.

Conclusions: These results suggest that SRA is involved in proliferation, migration, and invasion of endometrial cancer cells by increasing the expression of EIF4E-BP1 and activity of Wnt/ β-catenin signaling. These findings indicate that SRA might be a novel biomarker for predicting recurrence and prognosis. It might also serve as a promising therapeutic target in endometrial cancer.

LOC134466 methylation promotes oncogenesis of endometrial carcinoma through LOC134466/hsa-miR-196a-5p/TAC1 axis

To investigate possible mechanism of abnormal methylation of long non-coding RNA (lncRNA) on endometrial carcinoma (EC) progression, we detected the genome methylation profiling of endometrial carcinoma by bioinformatic analysis. Accordingly, gene LOC134466 was chosen for the further research. We also found that TAC1 was the target gene of LOC134466 and miRNA, hsa-miR-196a-5p, might form a connection between LOC134466 and TAC1. The relationship was further proved by dual-luciferase reporter assay. In vitro studies, DNA methylation and expression were determined by MSP and qRT-PCR respectively. Cell proliferation, apoptosis and cell cycle were demonstrated by colony formation assay, Annexin V/PI double staining and flow cytometry. Besides, the function of LOC134466 and TAC1 in EC was further confirmed by Tumor Xenograft. Our results indicated that EC progression was promoted by hypermethylated LOC134466 and TAC1. Moreover, TAC1 transcription was regulated by LOC134466 via hsa-miR-196a-5p binding. LOC134466 and TAC1 demethylation by 5-Aza-2-Deoxycytidine inhibited EC cells proliferation and accelerated cell apoptosis. Furthermore, the expression of TACR1, TACR2 and TACR3 was remarkably decreased through LOC134466 and TAC1 treatments. Our findings establish a novel regulatory axis, LOC134466/hsa-miR-196a-5p/TAC1. Downregulation of the axis promoted EC development through TACR3, which further activated neuroactive ligand-receptor interaction.

Prediction of overall survival time in patients with colon adenocarcinoma using DNA methylation profiling of long non-coding RNAs

Long non-coding RNAs (lncRNAs) are a subgroup of RNAs able to regulate gene expression at the epigenetic level, and are therefore central to the regulation of numerous biological processes and the progression of multiple cancer types. However, lncRNAs have not been identified to considerably influence overall survival (OS) outcome in numerous different types of cancer. The majority of studies investigating the association between lncRNAs and epigenetic regulation have focused on their altered expression levels in cancerous cells, and few studies have focused on determining the correlation between lncRNAs and OS time. In the present study, comprehensive lncRNA expression analysis was performed on a cohort of patients diagnosed with colon adenocarcinoma (COAD) using the least absolute shrinkage and selection operator method (LASSO). Subsequently, the construction of a prognostic methylation-based predictive system was performed based on the results of LASSO analysis. Functional enrichment analysis of lncRNA co-expression genes was also performed. According to the results of the present study, the classifier was able to significantly predict the prognosis of patients with COAD, and the investigation of the relevant elucidated genes further revealed the mechanism of COAD pathogenesis.

Long Noncoding RNA HOTAIR Promotes Endometrial Carcinoma Cell Proliferation by Binding to PTEN via the Activating Phosphatidylinositol 3-Kinase/Akt Signaling Pathway

Accumulating evidence has demonstrated that long noncoding RNAs (lncRNAs) exert essential biological functions in modulating the progression of endometrial carcinoma (EC). HOX transcript antisense intergenetic RNA (HOTAIR) has been widely recognized as a crucial mediator in various tumors, including EC. However, the specific molecular mechanism of HOTAIR in the development of EC remains to be further explored. In the present study, we demonstrated that HOTAIR was significantly upregulated in EC tissues; this was negatively correlated with PTEN but positively correlated with phosphatidylinositol 3-kinase (PI3K) and Akt. Overexpression of HOTAIR promoted proliferation and inhibited apoptosis of EC cells, similar to PTEN knockdown. Additionally, RNA pulldown demonstrated the direct binding relationship between HOTAIR and PTEN. Furthermore, HOTAIR activated the PI3K/Akt pathway to promote EC progression by suppressing PTEN in vivo Taking these results together, we revealed that high expression of HOTAIR promoted cell proliferation and inhibited apoptosis through activating the PI3K/Akt pathway via binding to PTEN, which might provide a prognostic marker and therapeutic target of EC.

Long noncoding RNA LSINCT5 promotes endometrial carcinoma cell proliferation, cycle, and invasion by promoting the Wnt/β-catenin signaling pathway via HMGA2

Background:

A review of the evidence has indicated the critical role of long noncoding RNA (lncRNA) LSINCT5 in a large number of human cancers. However, the mechanistic involvement of LSINCT5 in endometrial carcinoma (EC) is still unknown. Here the authors aim to characterize the expression status of LSINCT5 and elucidate its mechanistic relevance to EC.

Methods:

Relative expression of LSINCT5 and HMGA2 were quantified by a real-time polymerase chain reaction. SiRNAs were employed to specifically knockdown endogenous LSINCT5 in EC cells. Cell proliferation was measured with Cell Count Kit-8 kit (CCK-8, Dojindo, Kumamoto, Japan) and cell growth was assessed by a colony formation assay. The cell cycle was analyzed with propidium iodide (PI) staining. Apoptotic cells were determined by flow cytometry after Annexin V/PI double-staining. Cell migration was evaluated by a wound-healing assay, and cell invasion was assessed using a transwell migration assay. The protein levels of HMGA2, Wnt3a, p-β-catenin, c-myc, β-actin, and GAPDH were determined by western blot.

Results:

The authors observed positively correlated and aberrantly up-regulated LSINCT5 and HMGA2 in EC. LSINCT5 deficiency significantly inhibited cell proliferation, cell cycle progression, and induced apoptosis. Meanwhile, cell migration and invasion were greatly compromised by the LSINCT5 knockdown. LSINCT5 stabilized HMGA2, which subsequently stimulated activation of Wnt/β-catenin signaling and consequently contributed to the oncogenic properties of LSINCT5 in EC.

Conclusions:

Our data uncovered the oncogenic activities and highlighted the mechanistic contributions of the LSINCT5-HMGA2-Wnt/β-catenin signaling pathway in EC.

Long non-coding RNAs and endometrial cancer

Endometrial cancer (EC) is one of the most common gynecologic malignancies. In spite of the advance in chemotherapy, radiotherapy or surgical techniques for EC in recent years, the survival rate of advanced stage EC patients remains unsatisfactory. Long non-coding RNAs (lncRNAs) are known as transcripts longer than 200 nucleotides exhibiting no or limited protein-coding potential. Growing evidence suggested lncRNAs may be a critical class of pervasive genes involved in cancer progression. However, the function and biological relevance between lncRNAs and EC remain not yet fully understood. Accumulating evidence has indicated that lncRNAs are dysregulated in EC, and closely related to tumorigenesis, metastasis and chemoresistance. In this review, we summarize the known regulation and functional roles of lncRNAs in EC. Besides, we will discuss the potential of lncRNAs as diagnostic biomarkers and therapeutic targets in EC.

Knockdown of differentiation antagonizing non-protein coding RNA exerts anti-tumor effect by up-regulating miR-214 in endometrial carcinoma

Differentiation antagonizing non-protein coding RNA (DANCR) is a valuable long noncoding RNA (lncRNA) that involves in the progress of various cancers. However, the functions of DANCR in endometrial carcinoma (EC) have not been validated. In the present study, we aimed to evaluate the roles of DANCR in EC and explore the underlying mechanism. Expression patterns of DANCR in EC specimens and normal control specimens were determined using qRT-PCR. DANCR was knocked down in EC cell lines (AN3CA and HEC-1B) through transfection with small interfering RNA (siRNA) targeting DANCR (si-DANCR). Cell proliferation was examined using the cell counting kit-8 (CCK-8) assay. Cell apoptosis was measured by flow cytometry. Online software starBase was used to predict the target gene of DANCR. Luciferase reporter assay was carried out to confirm the association between DANCR and the predicted target microRNA (miRNA). DANCR expression was up-regulated in EC tissues as compared to the normal control tissues. Knockdown of DANCR in AN3CA and HEC-1B cells markedly suppressed cell proliferation and induced cell apoptosis. miR-214 was found to be a target miRNA of DANCR and its expression was significantly decreased in EC tissues. Suppression of miR-214 abolished the effects of si-DANCR on cell proliferation and apoptosis in AN3CA and HEC-1B cells. DANCR played an important role in promoting tumorigenesis of EC via sponging miR-214. DANCR might serve as a therapeutic target for the treatment of EC.

Long non-coding RNA H19 regulates cell growth and metastasis via miR-138 in breast cancer

Breast cancer is one of the most common cancers among women. Long non-coding RNAs (lncRNAs) are involved in the initiation and development of breast cancer and lncRNA H19 is a potential oncogenic factor; however, the underlying mechanisms remain unknown. In the present study, the regulatory functions of H19 in breast cancer were investigated. We found that H19 was upregulated in breast cancer tissues and cells and associated with poor prognosis. MiR-138 was downregulated in breast cancer tissues and negatively correlated with the expression of H19 and SOX4. Furthermore, SOX4 was upregulated in breast cancer tissues and positively correlated with H19. Downregulated H19 suppressed the proliferation, invasion and migration of breast cancer cells, but promoted cell cycle arrest and apoptosis. Additionally, miR-138 was identified as a direct target of H19 and SOX4; overexpression of miR-138 inhibited the proliferation, invasion and migration of MDA-MB-231 and MCF-7 cells, but promoted apoptosis, which were abrogated by SOX4 overexpression. Downregulated miR-138 induced cell proliferation, invasion and migration, but inhibited apoptosis of MDA-MB-231 and MCF-7 cells, which were promoted by SOX4 overexpression. In addition, miR-138 overexpression reversed the effects of H19 in breast cancer cells; silencing of H19 inhibited tumor growth and downregulate EMT markers in vivo. In summary, H19 was upregulated in breast cancer and associated with poor prognosis. Silencing of H19 inhibited cell proliferation, invasion and migration, but induced cell cycle arrest and apoptosis by regulating miR-138 and SOX4 in breast cancer.

LncRNA-H19 regulates cell proliferation and invasion of ectopic endometrium by targeting ITGB3 via modulating miR-124-3p

Endometriosis, a common gynecological disease, is associated with pelvic pain and infertility. Endometriosis affects approximately 10% of women, but that number increases to 30-50% in symptomatic premenopausal women. Despite the prevalence of endometriosis, the cause has yet to be fully elucidated. Recent study of the molecular pathways of endometrial cancer has brought the long non-coding RNA (lncRNA) H19 to our attention. In this paper, we explored the role of lncRNA-H19 in endometrial tissue proliferation. We found that ectopic endometrial cells taken from women with endometriosis showed elevated levels of lncRNA-H19, with expression levels correlating to disease progression. Knockdown of H19 in ectopic endometrial cells inhibited cell proliferation and invasion. Coinciding with this change was an increase in microRNA-124-3p (miR-124-3p) and a decrease in integrin beta-3 (ITGB3) levels. The addition of a miR-124-3p inhibitor mitigated this decrease in ITGB3. Up-regulation of miR-124-3p markedly suppressed ITGB3 expression by binding to the 3' untranslated region (3' UTR), while inhibition of miR-124-3p had the opposite effect. ITGB3 overexpression potently counteracted the effects of miR-124-3p mimics on ectopic endometrial cells. From these results, we can infer that in endometriosis both miR-124-3p and ITGB3 operate as downstream effector proteins in the H19-signaling pathway. Down-regulation of lncRNA-H19 could inhibit ectopic endometrial cell proliferation and invasion by modulating miR-124-3p and ITGB3, offering a novel target for treatment.

Functional interactions between scaffold proteins, noncoding RNAs, and genome loci induce liquid-liquid phase separation as organizing principle for 3-dimensional nuclear architecture: implications in cancer

The eukaryotic cell nucleus consists of functionally specialized subcompartments. These nuclear subcompartments are biomolecular aggregates built of proteins, transcripts, and specific genome loci. The structure and function of each nuclear subcompartment are defined by the composition and dynamic interaction between these 3 components. The spatio-temporal localization of biochemical reactions into membraneless nuclear subcompartments can be achieved through liquid-liquid phase separation. Based on this organizing principle, nuclear subcompartments are droplet-like structures that adopt spherical shapes, flow, and fuse like liquids or gels. In the present review, we bring into the spotlight seminal works elucidating the functional interactions between scaffold proteins, noncoding RNAs, and genomic loci, thereby inducing liquid-liquid phase separation as an organizing principle for 3-dimensional nuclear architecture. We also discuss the implications in different cancer types as well as the potential use of this knowledge to develop novel therapeutic strategies against cancer.-Rubio, K., Dobersch, S., Barreto, G. Functional interactions between scaffold proteins, noncoding RNAs, and genome loci induce liquid-liquid phase separation as organizing principle for 3-dimensional nuclear architecture: implications in cancer.

Long Noncoding RNA-ATB Impairs the Function of Tumor Suppressor miR-126-Mediated Signals in Endometrial Cancer for Tumor Growth and Metastasis

OBJECTIVE

Long non-coding RNA-ATB (Lnc-ATB) have been reported to promote tumor proliferation and metastasis via regulation of tumor suppressive miRNA-related signals. Patients with endometrial cancer (EC) have advanced stage disease or metastasis have poor prognosis. We here investigated the role of Lnc-ATB in endometrial cancer.

METHODS

Endometrial cancer tissues and normal tissues (n = 35) were collected to determine the expression and clinical significance of Lnc-ATB, and bioinformatics analysis was used to predict the miRNA target. siRNA was used to estimate the function of Lnc-ATB in EC cell lines and in vivo.

RESULT

The expression of Lnc-ATB is up-regulated in tumor tissues and EC cell lines. Patients with high expressed Lnc-ATB have high FIGO stage and poor tumor differentiation. The tumor suppressor miR-126 interacted with Lnc-ATB. Down-regulated miR-126 negative correlated with FIGO stage and tumor differentiation. Knockdown of Lnc-ATB in RL95 and HEC1A cell lines increased the miR-126 level and impaired the cell vitality, induced caspase-3-related tumor apoptosis and G1/S arrest. However, abrogation of miR-126 by its inhibitors counteracted Lnc-ATB knockdown-induced tumor inhibition via regulation of miR-126 target gene PIK3R2 and Sox2-related apoptosis and cell cycle pathway. Meanwhile, Lnc-ATB knockdown also suppressed the migration and invasion and inhibited TGF-β-induced epithelial-mesenchymal transition (EMT) phenotype via miR-126. Knockdown of Lnc-ATB in vivo remarkably induced tumor regression via restoration of tumor suppressor miR-126, leading to deceased tumor volume, reduced expression of PCNA and PIK3R2/Sox2 signals and EMT phenotype in tumor tissues.

CONCLUSION

These data demonstrate the tumorigenic role of Lnc-ATBs in endometrial cancer via abrogation of tumor suppressor miR-126 signals.

Screening of prognostic biomarkers for endometrial carcinoma based on a ceRNA network

Objective

This study aims to reveal the regulation network of lncRNAs-miRNAs-mRNA in endometrial carcinoma (EC), to investigate the underlying mechanisms of EC occurrence and progression, to screen prognostic biomarkers.

Methods

RNA-seq and miRNA-seq data of endometrial carcinoma were downloaded from the TCGA database. Edge.R package was used to screen differentially expressed genes. A database was searched to determine differentially expressed lncRNA-miRNA and miRNA-mRNA pairs, to construct the topological network of ceRNA, and to elucidate the key RNAs that are for a prognosis of survival.

Results

We screened out 2632 mRNAs, 1178 lncRNAs and 189 miRNAs that were differentially expressed. The constructed ceRNA network included 97 lncRNAs, 20 miRNAs and 73 mRNAs. Analyzing network genes for associations with prognosies revealed 169 prognosis-associated RNAs, including 92 lncRNAs, 16miRNAs and 61 mRNAs.

Conclusion

Our results reveal new potential mechanisms underlying the carcinogenesis and progression of endometrial carcinoma.

H19 long non-coding RNA contributes to sphere formation and invasion through regulation of CD24 and integrin expression in pancreatic cancer cells

The long non-coding RNA H19 is highly expressed in several cancers, and the functions of H19 vary among cancer cell types. Recently, we reported that H19 contributes to the metastasis of pancreatic ductal adenocarcinoma (PDAC) cells and that inhibition of H19 reduces metastasis in vivo. However, the molecular mechanisms underlying the metastasis-promoting role of H19 in PDAC cells remain poorly elucidated. In this study, we clarified the mechanisms by which H19 regulates PDAC metastasis, with a focus on cancer stem cells (CSCs), by using H19-overexpressing and knockdown PDAC cells. Whereas the sphere-formation and invasion abilities of PDAC cells depended on H19 expression levels, other CSC characteristics of the cells, including stemness-marker expression and anticancer-drug resistance, were unaffected by H19 levels. Furthermore, metalloproteinase activity, a key mediator of invasion, was also independent of H19 expression. By contrast, H19 promoted cell adhesion through regulation of integrin and CD24 expression. Notably, the increased adhesion of H19-overexpressing cells was blocked by an anti-β1-integrin antibody, and this resulted in the inhibition of sphere formation and invasion. Thus, H19 plays critical roles in the CSC self-renewal and cell adhesion of PDAC that lead to invasion and metastasis. Our findings suggest that H19 represents a novel therapeutic target for the metastasis of pancreatic cancer.

Non-Coding RNAs in Endometrial Physiopathology

The Human Genome Project led to the discovery that about 80% of our DNA is transcribed in RNA molecules. Only 2% of the human genome is translated into proteins, the rest mostly produces molecules called non-coding RNAs, which are a heterogeneous class of RNAs involved in different steps of gene regulation. They have been classified, according to their length, into small non-coding RNAs and long non-coding RNAs, or to their function, into housekeeping non-coding RNAs and regulatory non-coding RNAs. Their involvement has been widely demonstrated in all cellular processes, as well as their dysregulation in human pathologies. In this review, we discuss the function of non-coding RNAs in endometrial physiology, analysing their involvement in embryo implantation. Moreover, we explore their role in endometrial pathologies such as endometrial cancer, endometriosis and chronic endometritis.

Long noncoding RNA LINC00261 regulates endometrial carcinoma progression by modulating miRNA/FOXO1 expression

Long noncoding RNA LINC00261 was reported to be downregulated in multiple cancers. LINC00261 overexpression inhibits cancer cell proliferation, migration, and invasion. But the expression and function of LIN00261 in endometrial carcinoma are still elusive. We found that LINC00261 mRNA levels were downregulated in endometrial carcinoma, and LINC00261 overexpression inhibited endometrial carcinoma cell proliferation, migration, and invasion. miRNAs, including miR-182, miR-183, miR-153, miR-27a, and miR-96, were predicted to bind LINC00261 and FOXO1, and functioned to attenuate expression of LINC00261 and FOXO1. Overexpressed LINC00261 lowered these dissociative miRNAs, resulting in increase of FOXO1 protein levels. The knockdown of FOXO1 eliminated the suppression effect of overexpressed LINC00261 on endometrial carcinoma cell aggressiveness. LINC00261 promotes FOXO1 expression through reducing FOXO1-targeted miRNAs to suppress endometrial carcinoma cell proliferation, migration, and invasion.

SIGNIFICANCE OF THE STUDY

LINC00261 is downregulated in endometrial carcinoma and associated with metastasis of this cancer. LINC00261 elevates FOXO1 protein levels through reducing FOXO1-targeted miRNAs to suppress endometrial carcinoma cell proliferation, migration, and invasion.

Non-coding RNAs: long non-coding RNAs and microRNAs in endocrine-related cancers

The human genome is 'pervasively transcribed' leading to a complex array of non-coding RNAs (ncRNAs) that far outnumber coding mRNAs. ncRNAs have regulatory roles in transcription and post-transcriptional processes as well numerous cellular functions that remain to be fully described. Best characterized of the 'expanding universe' of ncRNAs are the ~22 nucleotide microRNAs (miRNAs) that base-pair to target mRNA's 3' untranslated region within the RNA-induced silencing complex (RISC) and block translation and may stimulate mRNA transcript degradation. Long non-coding RNAs (lncRNAs) are classified as >200 nucleotides in length, but range up to several kb and are heterogeneous in genomic origin and function. lncRNAs fold into structures that interact with DNA, RNA and proteins to regulate chromatin dynamics, protein complex assembly, transcription, telomere biology and splicing. Some lncRNAs act as sponges for miRNAs and decoys for proteins. Nuclear-encoded lncRNAs can be taken up by mitochondria and lncRNAs are transcribed from mtDNA. Both miRNAs and lncRNAs are dysregulated in endocrine cancers. This review provides an overview on the current understanding of the regulation and function of selected lncRNAs and miRNAs, and their interaction, in endocrine-related cancers: breast, prostate, endometrial and thyroid.

Non-Coding RNAs and Endometrial Cancer

Non-coding RNAs (ncRNAs) are involved in the regulation of cell metabolism and neoplastic transformation. Recent studies have tried to clarify the significance of these information carriers in the genesis and progression of various cancers and their use as biomarkers for the disease; possible targets for the inhibition of growth and invasion by the neoplastic cells have been suggested. The significance of ncRNAs in lung cancer, bladder cancer, kidney cancer, and melanoma has been amply investigated with important results. Recently, the role of long non-coding RNAs (lncRNAs) has also been included in cancer studies. Studies on the relation between endometrial cancer (EC) and ncRNAs, such as small ncRNAs or micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), antisense RNAs (asRNAs), small nuclear RNAs (snRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), competing endogenous RNAs (ceRNAs), lncRNAs, and long intergenic ncRNAs (lincRNAs) have been published. The recent literature produced in the last three years was extracted from PubMed by two independent readers, which was then selected for the possible relation between ncRNAs, oncogenesis in general, and EC in particular.

The Role of Long Non-Coding RNAs in Osteosarcoma

Long non-coding RNAs (lncRNAs) constitute non-protein coding transcripts with a size > than 200 nucleotides. They are involved in many cellular processes, such as chromatin remodelling, transcription, and gene expression. They play a role in the development, progression, and invasion of many human cancers, including osteosarcoma. This rare tumor entity predominantly arises in children and young adults. Treatment consists of polychemotherapy and surgical resection, increasing survival rates up to 60%. In the present review, the role of lncRNAs with prognostic, predictive, therapeutic, and diagnostic significance in osteosarcoma is discussed. Moreover, their potential application in clinical practice is highlighted.

Metformin inhibits tumorigenesis in HBV-induced hepatocellular carcinoma by suppressing HULC overexpression caused by HBX

We aimed to understand whether metformin imposes the inhibitory effect on the HBV-associated tumorigenesis by regulating the HULC and its downstream signaling pathway. Luciferase assay, RT-PCR, and Western-blot, MTT and flow cytometry analysis were performed to understand and the mechanism, by which metformin enhance the inhibitory effect on the HBV-associated tumorigenesis by regulating the HULC and its downstream signaling pathway. HBX promoted viability of three types of cell lines, while metformin inhibited apoptosis of above two cells. ZEB1 was a direct downstream of miR-200a, which was further confirmed that miR-200a reduced luciferase activity of wild-type but not mutant ZEB1 3'UTR, and HULC was bound to region of miR-200a-3p using alignment prediction, but can't affect ZEB1 level. HULC transcription ability, HULC, ZEB1, and p18 levels were much higher in cell treated with HBX, while notably lower in cell treated with metformin, furthermore miR-200a level in cell showed an opposite trend as HULC, ZEB1, and p18 levels. HULC siRNA and miR-200a had no effect on HULC transcription ability, but decreased HULC, ZEB1, and p18 levels, and increased miR-200a expression. HBV (+) HCC +metformin exhibited a higher survival ratio and a lower recurrence rates than HBV (+) HCC group, HBV (-) HCC displayed an even higher survival ratio and an even lower recurrence rates than HBV (+) HCC + metformin groups. This study indicated that metformin imposed inhibitory effect on the HBV-associated HCC by negatively regulating the HULC/p18/miR-200a/ZEB1 signaling pathway.

Crosstalk between long non-coding RNAs and Wnt/β-catenin signalling in cancer

Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts in the human genome which perform crucial functions in diverse biological processes. The abnormal expression of some lncRNAs has been found in tumorigenesis, development and therapy resistance of cancers. They may act as oncogenes or tumour suppressors and can be used as diagnostic or prognostic markers, prompting their therapeutic potentials in cancer treatments. Studies have indicated that many lncRNAs are involved in the regulation of several signal pathways, including Wnt/β-catenin signalling pathway, which has been reported to play a significant role in regulating embryogenesis, cell proliferation and controlling tumour biology. Emerging evidences have suggested that lncRNAs can interact with several components of the Wnt/β-catenin signalling pathway to regulate the expression of Wnt target genes in cancer. Moreover, the expression of lncRNAs can also be influenced by the pathway. Nevertheless, Wnt/β-catenin signalling pathway-related lncRNAs and their interactions in cancer are not systematically analysed before. Considering these, this review emphasized the associations between lncRNAs and Wnt/β-catenin signalling pathway in cancer initiation, progression and their therapeutic influence. We also provided an overview on characteristics of lncRNAs and Wnt/β-catenin signalling pathway and discussed their functions in tumour biology. Finally, targeting lncRNAs or/and molecules associated with the Wnt/β-catenin signalling pathway may be a feasible therapeutic method in the future.

A novel lncRNA-focus expression signature for survival prediction in endometrial carcinoma

Background

Endometrial cancer (UCEC) is a complex malignant tumor characterized by both genetic level and clinical trial. Patients with UCEC exhibit the similar clinical features, however, they have distinct outcomes due to molecular heterogeneity. The aim of this study was to access the prognostic value of long non-coding RNAs (lncRNAs) in UCEC patients and to identify potential lncRNA signature for predicting patients’ survival and improving patient-tailored treatment.

Methods

We performed a comprehensive genome-wide analysis of lncRNA expression profiles and clinical data in a large cohort of 301 UCEC patients. UCEC patients were randomly divided into the discovery cohort (n = 150) and validation cohort (n = 151). A novel lncRNA-focus expression signature was identified in the discovery cohort, and independently accessed in the validation cohort. Additionally, the lncRNA signature was evaluated by multivariable Cox regression and stratification analysis as well as functional enrichment analysis.

Results

We detected a novel lncRNA-focus expression signature (LFES) consisting of 11 lncRNAs that were associated with survival based on risk scoring strategy in UCEC. The risk score based on the LFES was able to separate patients of discovery cohort into high-risk and low-risk groups with significantly different overall survival and progression-free survival, and has been successfully confirmed in the validation cohort. Furthermore, the LFES is an independent prognostic predictor of survival and demonstrates superior prognostic performance compared with the clinical covariates for predicting 5-year survival (AUC = 0.887). Functional analysis has linked the expression of prognostic lncRNAs to well-known tumor suppressor or ontogenetic pathways in endometrial carcinogenesis.

Conclusions

Our study revealed a novel 11-lncRNA signature to predict survival of UCEC patient. This lncRNA signature may be a valuable and alternative marker for risk evaluation to aid patient-tailored treatment and improve the outcome of patients with UCEC.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3983-0) contains supplementary material, which is available to authorized users.

Knockdown of lncRNA CCAT2 inhibits endometrial cancer cells growth and metastasis via sponging miR-216b

OBJECTIVE

Colon cancer-associated transcript 2 (CCAT2), a novel lncRNA has been reported as an oncogene in several cancers. This study was aimed to explore whether CCAT2 also exerted oncogenic roles in endometrial cancer cells.

MATERIALS AND METHODS

The expression of CCAT2 in 30 pairs of endometrial cancer and matched non-cancerous tissues were detected by qRT-PCR. Two endometrial cancer cell lines HEC-1-A and RL95-2 were used throughout this study. CCAT2 in cells was silenced by transfection with shRNA targeted CCAT2, then cell growth and metastasis were assessed by performing trypan blue staining, Transwell assay, and flow cytometry. Dual-luciferase reporter assay was used to detect the combination of miR-216b and CCAT2. Besides, the expression of miR-216b and Bcl-2 in cells were overexpressed or suppressed by transfection with their correspondingly mimic/vector or inhibitor/shRNA. qRT-PCR and western blot analysis were performed to detect the expression of Bcl-2 and main factors in PTEN/PI3K/AKT and mTOR signaling pathways.

RESULTS

CCAT2 was highly expressed in endometrial cancer tissues when compared to non-cancerous endometrial tissues. Knockdown of CCAT2 inhibited HEC-1-A and RL95-2 cells viability, migration, invasion, but induced apoptosis. CCAT2 was an endogenous sponge by competing for miR-216b, and miR-216b suppression alleviated CCAT2 silence-diminished cell growth and metastasis. miR-216b negatively regulated Bcl-2 and Bcl-2 could further active PTEN/PI3K/AKT and mTOR signaling pathways.

CONCLUSIONS

To conclude, these results demonstrated lncRNA CCAT2 was highly expressed in endometrial cancer tissues. Knockdown of CCAT2 inhibited cell growth and metastasis of endometrial cancer cells by sponging miR-216b.

Dysregulated expression of long noncoding RNAs in gynecologic cancers

Cancers of the female reproductive system include ovarian, uterine, vaginal, cervical and vulvar cancers, which are termed gynecologic cancer. The emergence of long noncoding RNAs (lncRNAs), which are believed to play a crucial role in several different biological processes, has made the regulation of gene expression more complex. Although the function of lncRNAs is still rather elusive, their broad involvement in the initiation and progression of various cancers is clear. They are also involved in the pathogenesis of cancers of the female reproductive system. LncRNAs play a critical physiological role in apoptosis, metastasis, invasion, migration and cell proliferation in these cancers. Different expression profiles of lncRNAs have been observed in various types of tumors compared with normal tissues and between malignant and benign tumors. These differential expression patterns may lead to the promotion or suppression of cancer development and tumorigenesis. In the current review, we present the lncRNAs that show a differential expression between cancerous and normal tissues in ovarian, cervical and endometrial cancers, and highlight the associations between lncRNAs and some of the molecular pathways involved in these cancers.

A meta-analysis: The diagnostic values of long non-coding RNA as a biomarker for gastric cancer

Long non-coding RNAs (lncRNAs) have been identified as novel biomarkers for the diagnosis, staging and prognosis for gastric cancer. However, various studies have reported a series of significances based on different diagnostic values. Therefore, the current study performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of lncRNAs for gastric cancer, and to discuss lncRNA types and sources of heterogeneity. The Cochrane Central Register of Controlled Trials, MEDLINE, PubMed, EMBASE, the Chinese Biomedical Literature Database, the China Academic Journals Full-text Database and the Chinese Scientific Journals Database were systematically searched for potential studies. Studies were included if they were associated with lncRNAs, gastric cancer and reported diagnostic outcomes. Analysis of diagnostic values was used to summarize the overall test performance of lncRNAs. Ten studies were included in this meta-analysis. The ranges of the diagnostic value of lncRNAs for gastric cancer were as follows: Sensitivity was 0.45–0.83, and pooled sensitivity was 0.63; specificity was 0.60–0.93, and pooled specificity was 0.75; positive likelihood ratio was 1.80–6.92, and pooled positive likelihood ratio was 2.51; negative likelihood ratio was 0.23–0.67, and pooled negative likelihood ratio was 0.50; diagnostic odds ratio was 3.33–13.75, and pooled diagnostic odds ratio was 5.47. An overall area under the curve value of the summary receiver operating characteristic curve was 0.7550. LncRNAs did not have a high accuracy for identifying gastric cancer at present, but may be a useful screening tool for diagnosing gastric cancer due to their correlation with gastric cancer biological features. LncRNAs are potential biomarkers for gastric cancer if the screening strategy is altered, or they are combined with other biomarkers to diagnose gastric cancer.

Regulation of NEAT1/miR-214-3p on the growth, migration and invasion of endometrial carcinoma cells

OBJECTIVE

To investigate the function and mechanism of lnc NEAT1 in regulating the growth, migration and invasion of endometrial carcinoma (EC) cells.

MATERIALS AND METHODS

NEAT1 and miR-214-3p levels were measured by qRT-PCR. The protein levels of HMGA1, β-catenin, c-myc and MMP9 were evaluated by Western blot. The effects of NEAT1, HMGA1, miR-214-3p on the viability, migration and invasion of HEC-1A cells were accessed by WST-1 assay and transwell migration/invasion assay. The effect of miR-214-3p on Wnt signaling activity was tested by luciferase reporter assay.

RESULTS

NEAT1, HMGA1 and β-catenin were significantly upregulated in EC tissues, and miR-214-3p was significantly downregulated. NEAT1 promoted the growth, migration and invasion of HEC-1A cells, and mRNA level of Wnt/β-catenin downstream genes c-myc and MMP9. In addition, HMGA1 upregualted the protein and mRNA levels of Wnt/β-catenin downstream genes c-myc and MMP9, and could improve cell viability, and increase numbers of migration and invasion of HEC-1A cells. miR-214-3p overexpression inhibited the proliferation, migration and invasion of HEC-1A cells, while NEAT1 overexpression reversed these effects. miR-214-3p overexpression inhibited the activity of Wnt/β-catenin pathway, while NEAT1 overexpression reversed this effect. Then, si-HMGA1 reduced the activity of Wnt/β-catenin pathway. Moreover, we found NEAT1 and HMGA1 bound to miR-214-3p by luciferase reporter assay, and NEAT1 and HMGA1 expression were negatively correlated with miR-214-3p.

CONCLUSION

NEAT1 regulates HMGA1 via miR-214-3p to regulate Wnt/β-catenin pathway, thus promotes the growth, migration and invasion of HEC-1A cells.

Function and Clinical Implications of Long Non-Coding RNAs in Melanoma

Metastatic melanoma is the most deadly type of skin cancer. Despite the success of immunotherapy and targeted agents, the majority of patients experience disease recurrence upon treatment and die due to their disease. Long non-coding RNAs (lncRNAs) are a new subclass of non-protein coding RNAs involved in (epigenetic) regulation of cell growth, invasion, and other important cellular functions. Consequently, recent research activities focused on the discovery of these lncRNAs in a broad spectrum of human diseases, especially cancer. Additional efforts have been undertaken to dissect the underlying molecular mechanisms employed by lncRNAs. In this review, we will summarize the growing evidence of deregulated lncRNA expression in melanoma, which is linked to tumor growth and progression. Moreover, we will highlight specific molecular pathways and modes of action for some well-studied lncRNAs and discuss their potential clinical implications.

Current Insights into Long Non-Coding RNAs (LncRNAs) in Prostate Cancer

The importance of long non-coding RNAs (lncRNAs) in the pathogenesis of various malignancies has been uncovered over the last few years. Their dysregulation often contributes to or is a result of tumour progression. In prostate cancer, the most common malignancy in men, lncRNAs can promote castration resistance, cell proliferation, invasion, and metastatic spread. Expression patterns of lncRNAs often change during tumour progression; their expression levels may constantly rise (e.g., HOX transcript antisense RNA, HOTAIR), or steadily decrease (e.g., downregulated RNA in cancer, DRAIC). In prostate cancer, lncRNAs likewise have diagnostic (e.g., prostate cancer antigen 3, PCA3), prognostic (e.g., second chromosome locus associated with prostate-1, SChLAP1), and predictive (e.g., metastasis-associated lung adenocarcinoma transcript-1, MALAT-1) functions. Considering their dynamic role in prostate cancer, lncRNAs may also serve as therapeutic targets, helping to prevent development of castration resistance, maintain stable disease, and prohibit metastatic spread.

Differential Expression and Clinical Significance of DNA Methyltransferase 3B (DNMT3B), Phosphatase and Tensin Homolog (PTEN) and Human MutL Homologs 1 (hMLH1) in Endometrial Carcinomas

BACKGROUND The aim of this study was to investigate the expression and the clinicopathologic significance of DNA methyltransferase 3B (DNMT3B), phosphatase and tensin homolog (PTEN) and human MutL homologs 1 (hMLH1) in endometrial carcinomas between Han and Uygur women in Xinjiang. MATERIAL AND METHODS The expression of DNMT3B, PTEN, and hMLH1 in endometrial carcinomas were assessed by immunohistochemistry, followed by an analysis of their relationship to clinical-pathological features and prognosis. RESULTS There were a 61.7% (95/154) overexpression of DNMT3B, 50.0% (77/154) loss of PTEN expression and 18.2% (28/154) loss of hMLH1 expression. The expression of DNMT3B and PTEN in endometrial carcinomas was statistically significantly different between Uygur women and Han women (p=0.001, p=0.010, respectively). DNMT3B expression was statistically significant based on the grade of endometrial carcinomas (p=0.031). PTEN loss was statistically significant between endometrioid carcinomas (ECs) and non endometrioid carcinomas (NECs) (p=0.040). DNMT3B expression was statistically significant in different myometrial invasion groups in Uygur women (p=0.010). Furthermore, the correlation of DNMT3B and PTEN expression was significant in endometrial carcinomas (p=0.021). PTEN expression was statistically significant in the overall survival (OS) rate of women with endometrial cancers (p=0.041). CONCLUSIONS Our findings suggest that PTEN and DNMT3B possess common regulation features as well as certain ethnic differences in expression between Han women and Uygur women. An interaction may exist in the pathogenesis of endometrial carcinoma. DNMT3B was expressed differently in cases of myometrial invasion and PTEN was associated with OS, which suggested that these molecular markers may be useful in the evaluation of the biological behavior of endometrial carcinomas and may be useful indicators of prognosis in women with endometrial carcinomas.

Prognostic and clinicopathological significance of long noncoding RNA H19 overexpression in human solid tumors: evidence from a meta-analysis

BACKGROUND

Many studies have reported that the expression level of lncRNA H19 was increased in various tumors. LncRNA H19 may play a significant role in cancer occurrence and development. An increased level of H19 was also associated with poor clinical outcomes of cancer patients.

RESULTS

12 eligible studies were screened, with a total of 1437 cancer patients. From the results of meta-analysis, as for prognosis, the patients with high expression of lncRNA H19 were shorter in OS (HR=1.08, 95% CI: 1.05-1.12). Statistical significance was also showed in subgroup meta-analysis stratified by the cancer type, analysis type and sample size. In addition, the patients detected with high H19 expression may be poorer in DFS (HR=1.27; 95% CI = 0.97-1.56). As for clinicopathology, it showed that increased H19 was related to poor histological grades (OR=2.31, 95% CI: 1.12-4.75), positive lymph node metastasis (OR=2.29, 95 % CI: 1.21-4.34) and advanced clinical stage (OR=4.83, 95% CI: 3.16-7.39).

MATERIALS AND METHODS

Eligible studies were collected by retrieving keywords in PubMed, Web of Science, Embase, CNKI and Wanfang database, from 1966 to April 23, 2016. This quantitative meta-analysis was performed with Stata SE12.0 and RevMan5.3 software. It aimed to explore the association between H19 expression level and prognosis and clinicopathology.

CONCLUSIONS

LncRNA-H19 may be a novel molecular marker for predicting solid tumors. It can also be a predictive factor of clinicopathological features in various cancers. Further studies are needed to verify the clinical utility of H19 in human cancers.

Current Status of Long Non-Coding RNAs in Human Breast Cancer

Breast cancer represents a major health burden in Europe and North America, as recently published data report breast cancer as the second leading cause of cancer related death in women worldwide. Breast cancer is regarded as a highly heterogeneous disease in terms of clinical course and biological behavior and can be divided into several molecular subtypes, with different prognosis and treatment responses. The discovery of numerous non-coding RNAs has dramatically changed our understanding of cell biology, especially the pathophysiology of cancer. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length. Several studies have demonstrated their role as key regulators of gene expression, cell biology and carcinogenesis. Deregulated expression levels of lncRNAs have been observed in various types of cancers including breast cancer. lncRNAs are involved in cancer initiation, progression, and metastases. In this review, we summarize the recent literature to highlight the current status of this class of long non-coding lncRNAs in breast cancer.