Downregulation of lncRNA TUBA4B is Associated with Poor Prognosis for Epithelial Ovarian Cancer

Role of DNA methylation and non‑coding RNAs expression in pathogenesis, detection, prognosis, and therapy‑resistant ovarian carcinoma (Review)

Ovarian cancer is the deadliest gynecological cancer globally, with epithelial ovarian cancer (EOC) comprising up to 90% of cases. A molecular characterization linking the histological subtypes with tumor grade in EOC has been suggested. Variations in genetic biomarkers such as BRCA1/2, MSH2, MLH1/6, BRIP1, and RAD51C/D have been studied in EOC. In addition, molecular characteristics, including DNA methylation and RNA transcription, are being explored as potential new biomarkers for the diagnosis and prognosis of this type of neoplasia. The present review focused on the role of DNA methylation and non‑coding RNA expression in the development of ovarian carcinomas and their association with diagnosis, prognosis, and the resistance of cancer cells to radiotherapy and chemotherapy. The present review considered the transition from the DNA structure to the RNA expression in ovarian carcinoma.

lncRNA-CCAT2 Reduces the Drug Resistance of Ovarian Cancer Cells

This study assesses lncRNA-CCAT2’s role in reducing the drug resistance of ovarian cancer cell lines. Cisplatin-resistant SKOV-3/DDP cells were established and assigned into CC group (transfected with lncRNA CCAT2 siRNA-NC) and CA group (transfected with lncRNA CCAT2 siRNA) followed by analysis of cell proliferation, apoptosis, expression of CCAT2, ERK1/2, Sp1 and relationship between CCAT2 and ERK1/2 and Sp1. CCAT2 expression in SKOV-3/DDP was higher than IOSE80 and SKOV-3 (P < 0.001). ERK1/2 expression in SKOV-3 and SKOV-3/DDP was 0.67±0.09, 1.97±0.40 (t = 14.18, P < 0.001). Sp1 level in SKOV-3 and SKOV-3/DDP was 0.49±0.05, 1.07±0.11 (P = 21.47, P < 0.001). Transfection of CCAT2 reduced cell fluorescence activity of ERK1/2 and Sp1 (P < 0.001). Cell proliferation in CC group and CA group had no difference at 0 h (P > 0.001) and the inhibition of cell proliferation was found at 24 h (P < 0.001). CC group (5.13±0.51) had lower cell apoptosis rate than CA group (20.52±2.24) (t = 29.96, P < 0.001) but higher ERK1/2 and Sp1 protein level CC group than CA group (P < 0.001). In conclusion, transfection of lncRNA-CCAT2 inhibits SKOV-3/DDP proliferation by targeting ERK1/2-Sp1 signaling pathway, promotes apoptosis and reduces drug resistance.

Downregulation of lncRNA ASMTL-AS1 in Epithelial Ovarian Cancer Correlates with Worse Prognosis and Cancer Progression

Given the characters of "Silent killer", epithelial ovarian cancer (EOC) usually suffered late diagnosis and poor prognosis. Therefore, this study aimed to explore the prognostic significance of ASMTL-AS1 in EOC and investigated the effect of lncRNA ASMTL-AS1 dysregulation on tumor cellular function. ASMTL-AS1 expression was analyzed in 133 EOC tissues and five kinds of cell lines by RT-qPCR. The expression of ASMTL-AS1 was tested for correlation with clinical data using the chi-square test and clinical follow-up using Kaplan-Meier method with log-rank test. Further, the prognostic parameters in predicting EOC overall survival were assessed by using multivariate Cox proportional hazards analysis. In vitro assays, including MTT assay and transwell assay, were conducted using EOC cell lines with overexpression of ASMTL-AS1. In tumorous tissues and cell lines, ASMTL-AS1 was lowly expressed compared with normal ones. This downregulation was associated with the advanced FIGO stage, positive ascites cytology, and lymph node. In particular, low levels of ASMTL-AS1 were revealed to have a high prognostic impact on EOC. ASMTL-AS1 overexpression strongly decreased cell proliferation, migration, and invasion in vitro partly by moderating miR-1228-3p. This study demonstrates a significant role for lowly expressed ASMTL-AS1 in EOC allowing for the prediction of prognosis for EOC. Considering that ASMTL-AS1 is strongly involved in cell growth and invasion, ASMTL-AS1 may be a promising marker for EOC prognosis and therapy.

N6-Methylandenosine-Related lncRNA Signature Is a Novel Biomarkers of Prognosis and Immune Response in Colon Adenocarcinoma Patients

Background

Colon adenocarcinoma (COAD) is the most common type of colon cancer. To date, however, the prognostic values of m6A RNA methylation-related long non-coding RNAs (lncRNAs) in COAD are largely unknown.

Materials and Methods

The m6A-related lncRNAs were identified from The Cancer Genome Atlas (TCGA) data set. Univariate and multivariate Cox regression analyses were performed to explore the prognostic m6A-related lncRNAs. Consistent clustering analysis was performed to classify the COAD patients into different subgroups based on the expression of m6A-related lncRNAs. The potential biological functions as well as differences in the stemness index and tumor immune microenvironment between different subgroups were analyzed. The prognostic m6A-related lncRNAs were used to establish an m6A-related lncRNA risk model to predict prognosis and survival status.

Results

We identified 31 m6A-associated lncRNAs with prognostic values from the TCGA data set. Based on the expression of prognostic m6A-associated lncRNAs, TCGA-COAD patients were classified into three clusters using consistent clustering analysis. There was a low correlation of tumor stemness between the three clusters but a significant correlation with the tumor immune microenvironment as well as the tumor mutational load. Thirty-one prognostic-related m6A-associated lncRNAs were used to construct a risk model, which was further determined by survival analysis, receiver operating characteristic (ROC) curve, and univariate and multifactor Cox analysis. The m6A-related risk model demonstrates good performance in predicting prognosis and survival status. The model-based high-risk group exhibited poorer overall survival (OS) compared with the low-risk group.

Conclusion

In this study, we construct a risk model that consists of 31 m6A-related lncRNAs with independent prognostic values in COAD. Our study shows the critical roles of these 31 m6A-related lncRNAs in the tumor immune microenvironment, indicating the prospect of informing prognostic stratification and the development of immunotherapeutic strategies for COAD patients.

Long non-coding RNAs: A view to kill ovarian cancer

An emerging role of long non-coding RNAs (lncRNAs) in tumor progression has been revealed in the last decade. Through interactions with nucleic acids and proteins, lncRNAs could act as enhancers, scaffolds or decoys for a number of oncoproteins and tumor suppressors. The aberrant lncRNA expression or mutations are often associated with changes in a variety of cellular processes, including proliferation, stress response and cell death. Here, we will focus on the tumor-associated lncRNAs in ovarian cancer according to their contribution to cancer hallmarks, such as intense proliferation, cell death resistance, altered energy metabolism, invasion and metastasis, and immune evasion. Moreover, the potential clinical implications of lncRNAs and their significance for the diagnosis, prognosis and therapy of ovarian cancer will be discussed.

Long non‑coding RNA OIP5‑AS1 facilitates the progression of ovarian cancer via the miR‑128‑3p/CCNG1 axis

Long non‑coding RNA (LncRNA) o‑phthalaldehyde-interacting protein 5 antisense transcript 1 (OIP5‑AS1) serves major roles in the progression of various types of cancer. The present study investigated its biological function in ovarian cancer (OC) and its mechanisms. The levels of OIP5‑AS1, microRNA‑128‑3p (miR‑128‑3p) and cyclin G1 (CCNG1) were examined by reverse transcription‑quantitative PCR. Cell viability, apoptosis, migration and invasion were detected to analyze cellular progression. Glycolytic metabolism was assessed by detecting the levels of glucose consumption and lactate production. CCNG1 and hexokinase 2 protein levels were measured by western blotting. Dual‑luciferase reporter assay, RNA immunoprecipitation and RNA pull‑down assays were performed to affirm the interaction between two molecules. OIP5‑AS1 was found to be upregulated in OC tissues and cells. Knockdown of OIP5‑AS1 suppressed cell viability, migration, invasion and glycolysis while promoting apoptosis in OC cells. OIP5‑AS1 interacted with miR‑128‑3p and functioned as an oncogene by sequestering miR‑128‑3p. In addition, CCNG1 was a target gene for miR‑128‑3p and miR‑128‑3p regulated the CCNG1‑induced effects on OC cells by downregulating CCNG1. OIP5‑AS1 upregulated the expression of CCNG1 via targeting miR‑128‑3p. OIP5‑AS1 knockdown also inhibited tumor growth of OC in vivo by modulating the expression of miR‑128‑3p and CCNG1. Collectively, these data illustrated that the oncogenic role of OIP5‑AS1 in OC was associated with the miR‑128‑3p/CCNG1 axis at least in part. OIP5‑AS1 might be a probable diagnostic and therapeutic biomarker for the treatment of OC patients.

The role of altered long noncoding RNAs in overall survival of ovarian cancer: A systematic review and meta-analysis

In recent years, tremendous research efforts have been focused on investigating the effect of dysregulation of lncRNAs on cancer progression, most of which confirm a positive link. This inspired us to conduct the present meta-analysis to explore whether aberrant expression of multiple lncRNAs has a role in patients' outcome in ovarian cancer. This comprehensive meta-analysis pertains to the evaluation of association between dysregulated lncRNAs expression level with eventual outcome and clinicopathological characteristics of ovarian cancer patients. We systematically searched PubMed, Web of Science, and Scopus to find all eligible articles. Pooled hazard ratios (HRs) and 95% confidence intervals (95% CIs) for overall survival, disease-free survival and progression-free survival were measured with a fixed or random effects model. A total of 34 studies were included in the meta-analysis. Dysregulation of lncRNAs were contributed to shorter overall survival (34 studies, 1180 patients HR = 2.12, 95% CI: 1.73 ± 2.60, random-effects) in ovarian cancer. Furthermore, altered lncRNAs were also related to decreased progression-free survival (8 studies, 1180 patients HR: 1.88, 95% CI: (1.35-2.62) and disease-free survival (2 studies, 285 patients, HR: 6.07, 95% CI: 1.28-28.78) in this disease. Our analyses supported the robust prognostic significance of altered lncRNAs in ovarian cancer. However, more extended studies are encouraged to evaluate the clinical application potential of these lncRNAs in the prognosis evaluation of ovarian cancer.

lncRNA RAET1K Promotes the Progression of Acute Myeloid Leukemia by Targeting miR-503-5p/INPP4B Axis

Background

Although long non-coding RNA (lncRNA) RAET1K has been observed to be abnormally expressed in patients with various cancers, its role and molecular mechanism in acute myeloid leukemia (AML) remain unclear.

Methods

The expression of RAET1K and miR-503-5p in bone marrow tissues and cell lines was detected by qRT-PCR. Cell proliferation was evaluated by cell counting kit-8 and 5-ethynyl-20-deoxyuridine (EdU) staining assay. Cell invasion and migration were detected by transwell assay. Cell apoptosis was evaluated by flow cytometry. The relationship between RAET1K and miR-503-5p, as well as miR-503-5p and INPP4B, was determined by luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In addition, the tumorigenesis of leukemia cells was evaluated by using a xenograft mouse model in vivo.

Results

RAET1K was significantly upregulated and miR-503-5p was markedly downregulated in bone marrow tissues and cell lines (HL-60 and THP-1). Silencing of RAET1K (si-RAET1K) and overexpression of miR-503-5p inhibited cell proliferation, migration, and invasion but promoted apoptosis of HL-60 and THP-1 cells. RAET1K functioned as a sponge of miR-503-5p, and miR-503-5p inhibitor obviously attenuated the effect of si-RAET1K on AML progression in vitro. INPP4B was identified as a target of miR-503-5p, and INPP4B overexpression obviously reversed the effect of miR-503-5p mimics on cell proliferation, migration, invasion, and apoptosis of HL-60 and THP-1 cells in vitro. Knockdown of RAET1K effectively inhibited the tumorigenesis of leukemia cells in vivo.

Conclusion

Our results demonstrated that RAET1K/miR-503-5p/INPP4B axis contributed to AML progression, suggesting that RAET1K might be a potential target for the treatment of AML.

A Positive Feedback Loop of lncRNA DSCR8/miR-98-5p/STAT3/HIF-1α Plays a Role in the Progression of Ovarian Cancer

Background

Accumulating studies have revealed that long non-coding RNA (lncRNA) and microRNA (miRNA) contribute to ovarian cancer (OC). DSCR8 has been found to mediate hepatocellular carcinoma development, while its role in OC remains to be explored.

Methods

In this study, lncRNA DSCR8 and miR-98-5p expressions in OC tissues and adjacent non-cancer tissues were determined by reverse transcriptase polymerase chain reaction (RT-PCR). Besides, gain-of-function or loss-of-function assays of DSCR8 and miR-98-5p were conducted on OC cell lines SKOV-3 and A2780. Cell proliferation was detected with Cell Counting Kit (CCK)8 and colony formation assay, and western blot was used to test the apoptotic levels of OC cells. Transwell assay was conducted to examine cell invasion, and the epithelial–mesenchymal transition (EMT) of OC cells was tested by western blot. Moreover, luciferase activity assay and RNA immunoprecipitation (RIP) assay were conducted to verify the relationships between DSCR8 and miR-98-5p, miR-98-5p, and signal transducer and activator of transcription 3 (STAT3).

Results

DSCR8 was remarkedly increased in OC tissues and associated with poorer survival of OC patients. Overexpressing DSCR8 promoted cell proliferation, invasion, and EMT but inhibited apoptosis. On the other hand, miR-98-5p was downregulated in OC tissues and relieved the progression of OC. Moreover, overexpressed DSCR8 increased the levels of STAT3 and hypoxia inducible factor 1 alpha (HIF-1α) and dampened the functions of miR-98-5p on OC. Pharmaceutical intervention of STAT3 and HIF-1α significantly altered the expressions of DSCR8 and miR-98-5p.

Conclusion

The present results suggested a positive feedback loop of lncRNA DSCR8/miR-98-5p/STAT3/HIF-α axis in the progression of OC.

[ARTICLE WITHDRAWN] Long Noncoding RNA KCNQ1OT1 Accelerates the Progression of Ovarian Cancer via MicroRNA-212-3/LCN2 Axis

ARTICLE WITHDRAWN: This article was withdrawn by the authors with the following Withdrawal Statement - The integrity of the current study is not acceptable. The authors intend to enrich the study to make it more valuable. Thus, the authors want to withdraw the current study. Please accept our apologies for this inconvenience and we hope for your understanding. Yours sincerely (on behalf of the authors), Xiaoqin Lu.

LncRNA TUG1 Regulates Cell Viability and Death by Regulating miR-193a-5p/Rab10 Axis in Acute Myeloid Leukemia

Background

Acute myeloid leukemia (AML) is a serious threat to human health. Long non-coding RNA (lncRNA) Taurine-Upregulated Gene1 (TUG1) has been reported to participate in the development and progression of several cancers, including AML. Herein, we aimed to investigate the pathognomonic role of TUG1 in AML cells and its potential mechanistic pathway.

Methods

Quantitative real-time PCR (qRT-PCR) assay was applied to detect the expression levels of lncRNA TUG1, miR-193a-5p and Rab10 in AML bone marrow and cell lines. The CCK-8 assay was conducted to assess the cell viability of AML HL-60 and NB4 cells and cell apoptotic assay was performed to assess the cell death. Dual-luciferase reporter assay was carried out to clarify the relationships among TUG1, miR-193a-5p and Rab10. Also, the protein level of Rab10 was examined by Western blot assay.

Results

LncRNA TUG1 was up-regulated in AML bone marrow and cells. Functional analysis showed that the silencing of TUG1 suppressed cell viability, while promoted cell death in AML HL-60 and NB4 cells. TUG1 targeted miR-193a-5p and negatively regulated miR-193a-5p expression. Overexpressed miR-193a-5p resulted in the decrease of cell viability and the increase in the cell death in AML cells. Restoration experiments proved that TUG1 regulated the cell viability and death of AML cells through regulating the miR-193a-5p/Rab10 axis. Rab10 was a direct target of miR-193a-5p and was inversely regulated by miR-193a-5p. TUG1 regulated the cell viability and death of AML cells through upregulating Rab10.

Conclusion

Silencing of lncRNA TUG1 induces a cytotoxic effect on AML cell lines through sponging miR-193a-5p and the suppression of Rab10.

Downregulated expression of lncRNA TUBA4B predicts unfavorable prognosis and suppresses glioma progression by sponging miR-183 to regulate SMAD4 expression

Introduction

Accumulating evidence has proved that long non-coding RNAs (lncRNAs) are involved in progression of glioma. Nevertheless, the role of TUBA4B in glioma remains unclear.

Material and methods

The expression of the target gene was measured by quantitative RT-PCR. The prognostic role of TUBA4B was analyzed by Meier survival analysis. Cell proliferation, colony formation, apoptosis, cell cycle, migration and invasion were detected by MTS, soft agar colony forming assay, flow cytometry, and transwell assay. The target interaction of the target gene was validated by the luciferase reporter assay, biotin pull-down assay, and RNA immunoprecipitation.

Results

We found that the expression of TUBA4B was lower in glioma tissues and cells. Moreover, patients with a low TUBA4B expression level exhibited poorer prognosis than those with high TUBA4B expression. Meanwhile, ROC analysis revealed that TUBA4B had diagnostic value to distinguish tumor patients from the healthy population. Overexpression of TUBA4B prohibited the malignancy of glioma, such as inhibition of proliferation, decrease of colony formation, arrest of the cell cycle, decline of migration and invasion, and promotion of cell apoptosis. In addition, we found that TUBA4B directly interacted with miR-183 and negatively regulated the expression of miR-183. We also observed that SMAD4 was a downriver target of miR-183 and TUBA4B subsequently exerted its tumor-suppressive effects by coordinating the expression of SMAD4 in glioma.

Conclusions

This study revealed for the first time that TUBA4B could be a tumor suppressor gene in glioma by adjustment of the TUBA4B/miR-183/SMAD4 axis, which may provide a useful prognostic biomarker and promising therapeutic target for glioma treatment.

The prognostic value of long noncoding RNA SNHG16 on clinical outcomes in human cancers: a systematic review and meta-analysis

BACKGROUND

Cancer has been a worldwide health problem with a high risk of morbidity and mortality, however ideal biomarkers for effective screening and diagnosis of cancer patients are still lacking. Small nucleolar RNA host gene 16 (SNHG16) is newly identified lncRNA with abnormal expression in several human malignancies. However, its prognostic value remains controversial. This meta-analysis aimed to synthesize available data to clarify the association between SNHG16 expression levels and clinical prognosis value in multiple cancers.

METHODS

Extensive literature retrieval was conducted to identify eligible studies, and data regarding SNHG16 expression levels on survival outcomes and clinicopathological features were extracted and pooled for calculation of the hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs). Forest plots were applied to show the association between SNHG16 expression and survival prognosis. Additionally, The Cancer Genome Atlas (TCGA) dataset was screened and extracted for validation of the results in this meta-analysis.

RESULTS

A total of eight studies comprising 568 patients were included in the final meta-analysis according to the inclusion and exclusion criteria. In the pooled analysis, high SNHG16 expression significantly predicted worse overall survival (OS) in various cancers (HR = 1.87, 95% CI 1.54-2.26, P < 0.001), and recurrence-free survival (RFS) in bladder cancer (HR = 1.68, 95% CI 1.01-2.79, P = 0.045). Meanwhile, stratified analyses revealed that the survival analysis method, tumor type, sample size, and cut-off value did not alter the predictive value of SNHG16 for OS in cancer patients. In addition, compared to the low SNHG16 expression group, patients with high SNHG16 expression were more prone to worse clinicopathological features, such as larger tumor size, advanced clinical stage, lymph node metastasis (LNM) and distant metastasis (DM). Exploration of TCGA dataset further validated that the upregulated SNHG16 expression predicted unfavorable OS and disease-free survival (DFS) in cancer patients.

CONCLUSIONS

The present study implicated that aberrant expression of lncRNA SNHG16 was strongly associated with clinical survival outcomes in various cancers, and therefore might serve as a promising biomarker for predicting prognosis of human cancers.

LncRNA TUBA4B functions as a competitive endogenous RNA to inhibit gastric cancer progression by elevating PTEN via sponging miR-214 and miR-216a/b

BACKGROUND

Emerging evidence demonstrates that long non-coding RNA (lncRNA) is an important regulator in tumorigenesis and development. Tubulin Alpha 4B (TUBA4B), a novel lncRNA, was recently proposed as a tumor suppressor in several human cancers. However, its role in gastric cancer (GC) remains unclear. In this study, we aimed to investigate the expression level, clinical implication, biological function and potential regulatory mechanism of TUBA4B in GC.

METHODS

qRT-PCR was employed to detect the expression of TUBA4B in GC tissues, cell lines and plasma. In vitro and in vivo experiments were carried out using colony formation/CCK-8/transwell invasion/cell apoptosis assay and xenograft tumor model, respectively. mRNA sequencing was used to identify the TUBA4B-related downstream genes.

RESULTS

TUBA4B was significantly decreased in GC tissues, cells and plasma. Low TUBA4B was positively correlated with larger tumor size, lymph node metastasis and advanced TNM stage. Moreover, TUBA4B was identified as an effective biomarker for the diagnosis and prognosis of patients with GC. Functionally, ectopic expression of TUBA4B inhibited GC cell proliferation, invasion and induced apoptosis in vitro as well as dampened tumor growth and metastasis in vivo. Furthermore, TUBA4B was found to be a competitive endogenous RNA (ceRNA) that could physically bind to and sequester miR-214 and miR-216a/b to increase the expression of their common downstream target PTEN, resulting in inactivation of PI3K/AKT signaling pathway, thereby retarding GC progression.

CONCLUSION

Our data highlight the compelling regulatory role of TUBA4B in GC, and reactivation of TUBA4B may be a promising therapeutic avenue for GC patients.

Long noncoding RNAs biomarker-based cancer assessment

Cancer diagnosis have mainly relied on the incorporation of molecular biomarkers as part of routine diagnostic tool. The molecular alteration ranges from those involving DNA, RNA, noncoding RNAs (microRNAs and long noncoding RNAs [lncRNAs]) and proteins. lncRNAs are recently discovered noncoding endogenous RNAs that critically regulates the development, invasion, and metastasis of cancer cells. They are dysregulated in different types of malignancies and have the potential to serve as diagnostic markers for cancer. The expression of noncoding RNAs is altered following many diseases, and besides, some of them can be secreted from the cells into the circulation following the apoptotic and necrotic cell death. These secreted noncoding RNAs are known as cell free RNA. These RNAs can be secreted from the cell through the apoptotic body, extracellular vesicles including microvesicle and exosome, and bind to proteins. Since, lncRNAs display high organ and cell specificity, can be found in the blood, urine, tumor tissue, or other tissues or bodily fluids of some patients with cancer, this review summarizes the most significant and up-to-date findings of research on lncRNAs involvement in different cancers, focusing on the potential of cancer-related lncRNAs as biomarkers for diagnosis, prognosis, and therapy.

LncRNAs in ovarian cancer

Ovarian cancer is one of the most common gynecologic malignancies and has a poor prognosis. Recently, long noncoding RNAs (lncRNAs) have been identified as key regulators of cancer development. Studies have shown that the dysregulation of lncRNAs is frequently observed in ovarian cancer and greatly contributes to malignant phenotypical changes. In this review, we provide perspectives on the involvement of lncRNAs in the proliferation, apoptosis, cell cycle, migration, invasion, metastasis and drug resistance of ovarian cancer based on recent discoveries. Then, we discuss the role of lncRNAs in predicting the prognosis of ovarian cancer. Finally, we provide insight into the potential of lncRNAs for evaluating the diagnosis and prognosis of ovarian cancer.

LncRNA myocardial infarction-associated transcript promotes cell proliferation and inhibits cell apoptosis by targeting miR-330-5p in epithelial ovarian cancer cells

INTRODUCTION

Long non-coding RNAs (lncRNAs) have been shown to have great importance in cancer development and progression. However, the mechanism of lncRNAs in epithelial ovarian cancer remains unclear. In the present study, we aimed to explore the role of the lncRNA myocardial infarction-associated transcript (MIAT) in epithelial ovarian cancer tumorigenesis.

MATERIAL AND METHODS

Quantitative real-time PCR (qRT-PCR) was used to determine MIAT expression in human epithelial ovarian cancer tissues and cell lines, and the effects of MIAT on cell proliferation and cell apoptosis were determined by CCK-8 assay or flow cytometry analysis. Dual-Luciferase Reporter assay and Western blot assay were used to explore the molecular mechanisms of MIAT in epithelial ovarian cancer cells progression.

RESULTS

Our data showed that the expression of lncRNA MIAT was remarkably increased in human epithelial ovarian cancer tissues and cell lines (p < 0.05). High MIAT expression was associated with poor overall survival of epithelial ovarian cancer patients (p < 0.05). Function assays showed that knockdown of MIAT expression significantly inhibited epithelial ovarian cancer cell proliferation and promoted cell apoptosis in vitro (p < 0.05). Moreover, we revealed that MIAT might function as an endogenous miR-330-5p sponge to regulate the target gene of miR-330-5p in epithelial ovarian cancer progression.

CONCLUSIONS

LncRNA MIAT was found to be a tumor oncogenic lncRNA in epithelial ovarian cancer tumorigenesis. LncRNA MIAT promoted cell proliferation and inhibited cell apoptosis by negative regulation of miR-330-5p in epithelial ovarian cancer cells. Our findings suggested that MIAT might act as a candidate prognostic biomarker and new therapeutic target for treating epithelial ovarian cancer patients.

RETRACTED: The function of long non-coding RNA MT1JP in the development and progression of gastric cancer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the Executive Editor (Chairman) as panels from Figures 3A,B and 4D are similar to panels from Figures 4A,B and 5E of the article published by Mingjun Bi, Hongmei Yu, Bin Huang and Cuiyan Tang in Gene 626 (2017) 337–343 http://dx.doi.org/10.1016/j.gene.2017.05.049. Also, Figures 3C and 4A are similar to Figures 4C and 5A of the Gene article. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. As such this article represents an abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Long non-coding RNA RP11-552M11.4 promotes cells proliferation, migration and invasion by targeting BRCA2 in ovarian cancer

The present study aimed to investigate the effect of long non‐coding RNA (lncRNA) RP11‐552M11.4 on cell proliferation, apoptosis, migration and invasion as well as its targeting genes in epithelial ovarian cancer (EOC) cells. LncRNA RP11‐552M11.4 expression was detected in 67 tumor tissues and paired adjacent tissues obtained from EOC patients. lncRNA RP11‐552M11.4 mimic/inhibitor plasmids were transferred into ovarian cancer cells (SKOV3, A‐2780) and normal ovarian epithelial cells (IOSE80 cells). In addition, rescue experiment was carried out by transferring BRCA2 inhibitor&lncRNA RP11‐552M11.4 inhibitor plasmids into SKOV3 and A‐2780 cells. qPCR, western blot, CKK‐8, Annexin V/propidium iodide (AV/PI), wound‐healing and Matrigel invasion assays were carried out to detect RNA expression, protein expression, cell proliferation, apoptosis, migration, and invasion, respectively. LncRNA RP11‐552M11.4 expression was elevated in tumor tissues compared with paired adjacent tissues and correlated with higher pathological grade, International Federation of Gynecology and Obstetrics stage and worse overall survival in EOC patients. LncRNA RP11‐552M11.4 promoted SKOV3 cell proliferation, migration and invasion whereas it inhibited apoptosis. Rescue experiment and luciferase reporter assay showed that lncRNA RP11‐552M11.4 regulated SKOV3 cells functions through binding BRCA2. Further experiments in A‐2780 cells also validated that lncRNA RP11‐552M11.4 induced A‐2780 cell proliferation while repressing apoptosis by targeting BRCA2. In addition, upregulation of lncRNA RP11‐552M11.4 increased IOSE80 cell proliferation, migration and invasion while decreasing apoptosis. In conclusion, lncRNA RP11‐552M11.4 correlates with worse prognosis, and promotes cell proliferation, migration, invasion, and inhibits cell apoptosis by down‐regulating BRCA2 in EOC.