Long non-coding RNAs in ovarian cancer

THUMPD3-AS1 inhibits ovarian cancer cell apoptosis through the miR-320d/ARF1 axis

Ovarian cancer is one of the most common gynecologic malignancies that has a poor prognosis. THUMPD3-AS1 is an oncogenic long noncoding RNA (lncRNA) in several cancers. Moreover, miR-320d is downregulated and inhibited proliferation in ovarian cancer cells, whereas ARF1 was upregulated and promoted the malignant progression in epithelial ovarian cancer. Nevertheless, the role of THUMPD3-AS1 in ovarian cancer and the underlying mechanism has yet to be elucidated. Human normal ovarian epithelial cells (IOSE80) and ovarian cancer cell lines (CAVO3, A2780, SKOV3, OVCAR3, and HEY) were adopted for in vitro experiments. The functional roles of THUMPD3-AS1 in cell viability and apoptosis were determined using CCK-8, flow cytometry, and TUNEL assays. Western blot was performed to assess the protein levels of ARF1, Bax, Bcl-2, and caspase 3, whereas RT-qPCR was applied to measure ARF1 mRNA, THUMPD3-AS1, and miR-320d levels. The targeting relationship between miR-320d and THUMPD3-AS1 or ARF1 was validated with dual luciferase assay. THUMPD3-AS1 and ARF1 were highly expressed in ovarian cancer cells, whereas miR-320d level was lowly expressed. THUMPD3-AS1 knockdown was able to repress cell viability and accelerate apoptosis of OVCAR3 and SKOV3 cells. Also, THUMPD3-AS1 acted as a sponge of miR-320d, preventing the degradation of ARF1. MiR-320d downregulation reversed the tumor suppressive function induced by THUMPD3-AS1 depletion. Additionally, miR-320d overexpression inhibited ovarian cancer cell viability and accelerated apoptosis, which was overturned by overexpression of ARF1. THUMPD3-AS1 inhibited ovarian cancer cell apoptosis by modulation of miR-320d/ARF1 axis. The discoveries might provide a prospective target for ovarian cancer treatment.

Current strategies for early epithelial ovarian cancer detection using miRNA as a potential tool

Ovarian cancer is one of the most aggressive and significant malignant tumor forms in the female reproductive system. It is the leading cause of death among gynecological cancers owing to its metastasis. Since its preliminary disease symptoms are lacking, it is imperative to develop early diagnostic biomarkers to aid in treatment optimization and personalization. In this vein, microRNAs, which are short sequence non-coding molecules, displayed great potential as highly specific and sensitive biomarker. miRNAs have been extensively advocated and proven to serve an instrumental part in the clinical management of cancer, especially ovarian cancer, by promoting the cancer cell progression, invasion, delayed apoptosis, epithelial-mesenchymal transition, metastasis of cancer cells, chemosensitivity and resistance and disease therapy. Here, we cover our present comprehension of the most up-to-date microRNA-based approaches to detect ovarian cancer, as well as current diagnostic and treatment strategies, the role of microRNAs as oncogenes or tumor suppressor genes, and their significance in ovarian cancer progression, prognosis, and therapy.

Survival-Associated Cellular Response Maintained in Pancreatic Ductal Adenocarcinoma (PDAC) Switched Between Soft and Stiff 3D Microgel Culture

Pancreatic ductal adenocarcinoma (PDAC) accounts for about 90% of all pancreatic cancer cases. Five-year survival rates have remained below 12% since the 1970s, in part due to the difficulty in detection prior to metastasis (migration and invasion into neighboring organs and glands). Mechanical memory is a concept that has emerged over the past decade that may provide a path toward understanding how invading PDAC cells "remember" the mechanical properties of their diseased ("stiff", elastic modulus, E ≈ 10 kPa) microenvironment even while invading a healthy ("soft", E ≈ 1 kPa) microenvironment. Here, we investigated the role of mechanical priming by culturing a dilute suspension of PDAC (FG) cells within a 3D, rheologically tunable microgel platform from hydrogels with tunable mechanical properties. We conducted a suite of acute (short-term) priming studies where we cultured PDAC cells in either a soft (E ≈ 1 kPa) or stiff (E ≈ 10 kPa) environment for 6 h, then removed and placed them into a new soft or stiff 3D environment for another 18 h. Following these steps, we conducted RNA-seq analyses to quantify gene expression. Initial priming in the 3D culture showed persistent gene expression for the duration of the study, regardless of the subsequent environments (stiff or soft). Stiff 3D culture was associated with the downregulation of tumor suppressors (LATS1, BCAR3, CDKN2C), as well as the upregulation of cancer-associated genes (RAC3). Immunofluorescence staining (BCAR3, RAC3) further supported the persistence of this cellular response, with BCAR3 upregulated in soft culture and RAC3 upregulated in stiff-primed culture. Stiff-primed genes were stratified against patient data found in The Cancer Genome Atlas (TCGA). Upregulated genes in stiff-primed 3D culture were associated with decreased survival in patient data, suggesting a link between patient survival and mechanical priming.

The pivotal role of long non-coding RNAs as potential biomarkers and modulators of chemoresistance in ovarian cancer (OC)

Ovarian cancer (OC) is a fatal gynecological disease that is often diagnosed at later stages due to its asymptomatic nature and the absence of efficient early-stage biomarkers. Previous studies have identified genes with abnormal expression in OC that couldn't be explained by methylation or mutation, indicating alternative mechanisms of gene regulation. Recent advances in human transcriptome studies have led to research on non-coding RNAs (ncRNAs) as regulators of cancer gene expression. Long non-coding RNAs (lncRNAs), a class of ncRNAs with a length greater than 200 nucleotides, have been identified as crucial regulators of physiological processes and human diseases, including cancer. Dysregulated lncRNA expression has also been found to play a crucial role in ovarian carcinogenesis, indicating their potential as novel and non-invasive biomarkers for improving OC management. However, despite the discovery of several thousand lncRNAs, only one has been approved for clinical use as a biomarker in cancer, highlighting the importance of further research in this field. In addition to their potential as biomarkers, lncRNAs have been implicated in modulating chemoresistance, a major problem in OC. Several studies have identified altered lncRNA expression upon drug treatment, further emphasizing their potential to modulate chemoresistance. In this review, we highlight the characteristics of lncRNAs, their function, and their potential to serve as tumor markers in OC. We also discuss a few databases providing detailed information on lncRNAs in various cancer types. Despite the promising potential of lncRNAs, further research is necessary to fully understand their role in cancer and develop effective strategies to combat this devastating disease.

Angio-Long Noncoding RNA MALAT1 (rs3200401) and MIAT (rs1061540) Gene Variants in Ovarian Cancer

The genotyping of long non-coding RNA (lncRNA)-related single-nucleotide polymorphisms (SNPs) could be associated with cancer risk and/or progression. This study aimed to analyze the angiogenesis-related lncRNAs MALAT1 (rs3200401) and MIAT (rs1061540) variants in patients with ovarian cancer (OC) using "Real-Time allelic discrimination polymerase chain reaction" in 182 formalin-fixed paraffin-embedded (FFPE) samples of benign, borderline, and primary malignant ovarian tissues. Differences in the genotype frequencies between low-grade ovarian epithelial tumors (benign/borderline) and malignant tumors and between high-grade malignant epithelial tumors and malignant epithelial tumors other than high-grade serous carcinomas were compared. Odds ratios (ORs)/95% confidence intervals were calculated as measures of the association strength. Additionally, associations of the genotypes with the available pathological data were analyzed. The heterozygosity of MALAT1 rs3200401 was the most common genotype (47.8%), followed by C/C (36.3%). Comparing the study groups, no significant differences were observed regarding this variant. In contrast, the malignant epithelial tumors had a higher frequency of the MIAT rs1061540 C/C genotype compared to the low-grade epithelial tumor cohorts (56.7% vs. 37.6, p = 0.031). The same genotype was significantly higher in high-grade serous carcinoma than its counterparts (69.4% vs. 43.8%, p = 0.038). Multivariate Cox regression analysis showed that the age at diagnosis was significantly associated with the risk of OC development. In contrast, the MIAT T/T genotype was associated with a low risk of malignant epithelial tumors under the homozygote comparison model (OR = 0.37 (0.16-0.83), p = 0.017). Also, MIAT T allele carriers were less likely to develop high-grade serous carcinoma under heterozygote (CT vs. CC; OR = 0.33 (0.12-0.88), p = 0.027) and homozygote (TT vs. CC; OR = 0.26 (0.07-0.90), p = 0.034) comparison models. In conclusion, our data provide novel evidence for a potential association between the lncRNA MIAT rs1061540 and the malignant condition of ovarian cancer, suggesting the involvement of such lncRNAs in OC development.

Network analysis of transcriptomic data uncovers molecular signatures and the interplay of mRNAs, lncRNAs, and miRNAs in human embryonic stem cells

Growing evidence has shown that besides the protein coding genes, the non-coding elements of the genome are indispensable for maintaining the property of self-renewal in human embryonic stem cells and in cell fate determination. However, the regulatory mechanisms and the landscape of interactions between the coding and non-coding elements is poorly understood. In this work, we used weighted gene co-expression network analysis (WGCNA) on transcriptomic data retrieved from RNA-seq and small RNA-seq experiments and reconstructed the core human pluripotency network (called PluriMLMiNet) consisting of 375 mRNA, 57 lncRNA and 207 miRNAs. Furthermore, we derived networks specific to the naïve and primed states of human pluripotency (called NaiveMLMiNet and PrimedMLMiNet respectively) that revealed a set of molecular markers (RPS6KA1, ZYG11A, ZNF695, ZNF273, and NLRP2 for naive state, and RAB34, TMEM178B, PTPRZ1, USP44, KIF1A and LRRN1 for primed state) which can be used to distinguish the pluripotent state from the non-pluripotent state and also to identify the intra-pluripotency states (i.e., naïve and primed state). The lncRNA DANT1 was found to be a crucial as it formed a bridge between the naive and primed state-specific networks. Analysis of the genes neighbouring DANT1 suggested its possible role as a competing endogenous RNA (ceRNA) for the induction and maintenance of human pluripotency. This was computationally validated by predicting the missing DANT1-miRNA interactions to complete the ceRNA circuit. Here we first report that DANT1 might harbour binding sites for miRNAs hsa-miR-30c-2-3p, hsa-miR-210-3p and hsa-let-7b-5p which may influence pluripotency.

Long noncoding RNA H19 in ovarian biology and placenta development

As the first long noncoding RNA to be discovered, H19 has gained substantial attention as a key regulator of several biological processes and its roles in female reproductive biology are gradually getting revealed. Herein, we have summarized the current evidence regarding H19 expression pattern and involvement in the developmental and pathological processes associated with the ovary and the placenta. The findings indicate that within the ovaries, H19 is expressed in the antral and cystic atretic follicles as well as in the corpora lutea but absent in the primordial, primary, and secondary follicles. Its normal expression promotes the maturation of antral follicles and prevents their premature selection for the ovulatory journey while its aberrant induction promotes polycystic ovary syndrome development and ovarian cancer metastasis. In the placenta, H19 is highly expressed in the cytotrophoblasts and extravillous trophoblasts but weakly expressed in the syncytiotrophoblast layer and potentially controls trophoblast cell fate decisions during placenta development. Abnormal expression of H19 is observed in the placental villi of pregnancies affected by pre-eclampsia and fetal growth restriction. Therefore, dysregulated H19 is a candidate biomarker and therapeutic target for the mitigation of ovarian and placenta-associated diseases.

Ultrasound coupled RES-loaded ultrasound microbubble inhibits the proliferation of ovarian cancer cells by expression of long non-coding RNA (lncRNA) involved in apoptosis using real-time PCR

The primary objective of this study was to evaluate the effect of low-frequency ultrasound combined with RES-loaded ultrasound microbubble contrast agents on the transcriptional and translational activities of ovarian cancer cells. After being cultures, ovarian cancer cells (OVCAR-3) and human umbilical cord endothelial cells (HUCEC) were transfected with siRNA, which was followed by RNA extraction and real-time PCR to evaluate transcriptional activity. Translational activity was determined by western blotting, which was followed by RNA interference. Proliferative and invasive activity was measured using cell proliferation, colony formation, and immunofluorescence assays. Lastly, RNA sequencing was performed. Our findings indicated that ultrasound combined with RES microbubbles inhibited cell proliferation and invasion. The expression of ING5 was enhanced, while the expression of EMT was suppressed in ovarian cancer cells. A negative correlation was observed between of the expression of ING5 and cell proliferation/migration, which were enhanced upon inhibition of ING5, suggesting dysregulation of transcriptional and translational cellular processes which could be of diagnostic and therapeutic value in ovarian cancer. Additionally, the dysregulation of lncRNAs can alter cellular homeostasis and promote ovarian cancer progression. A combination of low-frequency and RES-loaded ultrasound microbubbles was found to effectively inhibit the proliferation of OVCAR-3 ovarian cancer cells and induce apoptosis. This approach was more effective than low-frequency ultrasound combined with RES alone.

Comprehensive analyses of fatty acid metabolism-related lncRNA for ovarian cancer patients

Ovarian cancer (OC) is a disease with difficult early diagnosis and treatment and poor prognosis. OC data profiles were downloaded from The Cancer Genome Atlas. Eight key fatty acid metabolism-related long non-coding RNAs (lncRNAs) were finally screened for building a risk scoring model by univariate/ multifactor and least absolute shrinkage and selection operator (LASSO) Cox regression. To make this risk scoring model more applicable to clinical work, we established a nomogram containing the clinical characteristics of OC patients after confirming that the model has good reliability and validity and the ability to distinguish patient prognosis. To further explore how these key lncRNAs are involved in OC progression, we explored their relationship with LUAD immune signatures and tumor drug resistance. The structure shows that the risk scoring model established based on these 8 fatty acid metabolism-related lncRNAs has good reliability and validity and can better predict the prognosis of patients with different risks of OC, and LINC00861in these key RNAs may be a hub gene that affects the progression of OC and closely related to the sensitivity of current OC chemotherapy drugs. In addition, combined with immune signature analysis, we found that patients in the high-risk group are in a state of immunosuppression, and Tfh cells may play an important role in it. We innovatively established a prognostic prediction model with excellent reliability and validity from the perspective of OC fatty acid metabolism reprogramming and lncRNA regulation and found new molecular/cellular targets for future OC treatment.

Recent Insights into Noncoding RNAs in Primary Ovarian Insufficiency: Focus on Mechanisms and Treatments

CONTEXT

Primary ovarian insufficiency (POI) is a heterogeneous disease with an unknown underlying trigger or root cause. Recently many studies evaluated noncoding RNAs (ncRNAs), especially microRNAs (miRNAs), long noncoding RNA (lncRNAs), circular RNAs (circRNAs), and small interfering RNAs (siRNAs) for their associations with POI.

EVIDENCE ACQUISITION

In this review, we outline the biogenesis of various ncRNAs relevant to POI and summarize the evidence for their roles in the regulation of disease occurrence and progression. Articles from 2003 to 2022 were selected for relevance, validity, and quality from results obtained in PubMed and Google Scholar using the following search terms: noncoding RNAs; primary ovarian insufficiency; premature ovarian failure; noncoding RNAs and primary ovarian insufficiency/premature ovarian failure; miRNAs and primary ovarian insufficiency/premature ovarian failure; lncRNAs and primary ovarian insufficiency/premature ovarian failure; siRNAs and primary ovarian insufficiency/premature ovarian failure; circRNAs and primary ovarian insufficiency/premature ovarian failure; pathophysiology; and potential treatment. All articles were independently screened for eligibility by the authors.

EVIDENCE SYNTHESIS

This review summarizes the biological functions and synthesis of miRNAs, lncRNAs, siRNAs, and circRNAs in POI and discusses the findings of clinical and in vitro and in vivo studies. Although there is variability in the findings of individual studies, overall the available literature justifies the conclusion that dysregulated ncRNAs play significant roles in POI.

CONCLUSION

The potential of ncRNAs in the treatment of POI requires further investigation, as ncRNAs derived from mesenchymal stem cell-secreted exosomes play pivotal roles and have considerable therapeutic potential in a multitude of diseases.

Development and verification of a 7-lncRNA prognostic model based on tumor immunity for patients with ovarian cancer

BACKGROUND

Both immune-reaction and lncRNAs play significant roles in the proliferation, invasion, and metastasis of ovarian cancer (OC). In this study, we aimed to construct an immune-related lncRNA risk model for patients with OC.

METHOD

Single sample GSEA (ssGSEA) algorithm was used to analyze the proportion of immune cells in The Cancer Genome Atlas (TCGA) and the hclust algorithm was used to conduct immune typing according to the proportion of immune cells for OC patients. The stromal and immune scores were computed utilizing the ESTIMATE algorithm. Weighted gene co-expression network analysis (WGCNA) and differentially expressed genes (DEGs) analyses were utilized to detect immune cluster-related lncRNAs. The least absolute shrinkage and selection operator (LASSO) regression was conducted for lncRNA selection. The selected lncRNAs were used to construct a prognosis-related risk model, which was then validated in Gene Expression Omnibus (GEO) database and in vitro validation.

RESULTS

We identify two subtypes based on the ssGSEA analysis, high immunity cluster (immunity_H) and low immunity cluster (immunity_L). The proportion of patients in immunity_H cluster was significantly higher than that in immunity_L cluster. The ESTIMATE related scores are relative high in immunity_H group. Through WGCNA and LASSO analyses, we identified 141 immune cluster-related lncRNAs and found that these genes were mainly enriched in autophagy. A signature consisting of 7 lncRNAs, including AL391832.3, LINC00892, LINC02207, LINC02416, PSMB8.AS1, AC078788.1 and AC104971.3, were selected as the basis for classifying patients into high- and low-risk groups. Survival analysis and area under the ROC curve (AUC) of the signature pointed out that this risk model had high accuracy in predicting the prognosis of patients with OC. We also conducted the drug sensitive prediction and found that rapamycin outperformed in patient with high risk score. In vitro experiments also confirmed our prediction.

CONCLUSIONS

We identified 7 immune-related prognostic lncRNAs that effectively predicted survival in OC patients. These findings may offer a valuable indicator for clinical stratification management and personalized therapeutic options for these patients.

Emerging role of lncRNA ELDR in development and cancer

Whole-genome sequencing and transcriptome analysis revealed more than 90% of the human genome transcribes noncoding RNAs including lncRNAs. From the beginning of the 21st century, lncRNAs have gained widespread attention as a new layer of regulation in biological processes. lncRNAs are > 200 nucleotides in size, transcribed by RNA polymerase II, and share many similarities with mRNAs. lncRNA interacts with DNA, RNA, protein, and miRNAs, thereby regulating many biological processes. In this review, we have focused mainly on LINC01156 [also known as the EGFR long non-coding downstream RNA (ELDR) or Fabl] and its biological importance. ELDR is a newly identified lncRNA and first reported in a mouse model, but it has a human homolog. The human ELDR gene is closely localized downstream of epidermal growth factor receptor (EGFR) gene at chromosome 7 on the opposite strand. ELDR is highly expressed in neuronal stem cells and associated with neuronal differentiation and mouse brain development. ELDR is upregulated in head and neck cancer, suggesting its role as an oncogene and its importance in prognosis and therapy. Publicly available RNA-seq data further support its oncogenic potential in different cancers. Here, we summarize all the aspects of ELDR in development and cancer, highlighting its future perspectives in the context of mechanism.

LncRNA PART1 Stimulates the Development of Ovarian Cancer by Up-regulating RACGAP1 and RRM2

Ovarian cancer (OC) is a kind of gynecologic malignancy with a high mortality rate. Long non-coding RNAs (lncRNAs) have been reported to exert regulatory roles in multiple diseases. However, the role of lncRNA prostate androgen-regulated transcript 1 (PART1) has not been investigated in the development of OC. In this study, from RT-qPCR analysis, we discovered that PART1 demonstrated high expression in OC cells. Moreover, data from functional assays manifested that PART1 reduction hindered the proliferative, migratory, and invasive capabilities of OC cells. In vivo uncovered that PART1 knockdown impeded OC tumor growth. Furthermore, from the experimental results of RNA pull down, RIP, and luciferase reporter assays, we discovered that PART1 served as a sponge for microRNA-6884-5p (miR-6884-5p) to modulate the expression of Rac GTPase activating protein 1 (RACGAP1) and ribonucleotide reductase regulatory subunit M2 (RRM2). Finally, rescue assays proved that overexpression of RACGAP1 or RRM2 abrogated the suppressive role of PART1 knockdown on OC cell malignant behaviors. RACGAP1 and RRM2 were also revealed to act as oncogenes in OC cells. In summary, our research verified the PART1/miR-6884-5p/RACGAP1/RRM2 axis in OC cells, which signified that PART1 might act as a novel biomarker in OC.

ABHD11-AS1: An Emerging Long Non-Coding RNA (lncRNA) with Clinical Significance in Human Malignancies

The aberrant expression of lncRNAs has been linked to the development and progression of different cancers. One such lncRNA is ABHD11 antisense RNA 1 (ABHD11-AS1), which has recently gained attention for its significant role in human malignancies. ABHD11-AS1 is highly expressed in gastric, lung, breast, colorectal, thyroid, pancreas, ovary, endometrium, cervix, and bladder cancers. Several reports highlighted the clinical significance of ABHD11-AS1 in prognosis, diagnosis, prediction of cancer progression stage, and treatment response. Significantly, the levels of ABHD11-AS1 in gastric juice had been exhibited as a clinical biomarker for the assessment of gastric cancer, while its serum levels have prognostic potential in thyroid cancers. The ABHD11-AS1 has been reported to exert oncogenic effects by sponging different microRNAs (miRNAs), altering signaling pathways such as PI3K/Akt, epigenetic mechanisms, and N6-methyladenosine (m⁶A) RNA modification. In contrast, the mouse homolog of AHD11-AS1 (Abhd11os) overexpression had exhibited neuroprotective effects against mutant huntingtin-induced toxicity. Considering the emerging research reports, the authors attempted in this first review on ABHD11-AS1 to summarize and highlight its oncogenic potential and clinical significance in different human cancers. Lastly, we underlined the necessity for future mechanistic studies to unravel the role of ABHD11-AS1 in tumor development, prognosis, progression, and targeted therapeutic approaches.

Long non-coding RNA SNHG10 upregulates BIN1 to suppress the tumorigenesis and epithelial-mesenchymal transition of epithelial ovarian cancer via sponging miR-200a-3p

Epithelial ovarian cancer (EOC) is one of the most frequent and fatal gynecologic malignant tumors resulting in an unsatisfying prognosis. Long non-coding RNAs (lncRNAs) play pivotal roles in the tumorigenesis and progression of EOC. However, the profile of lncRNAs involved in EOC remains to be expanded to further improve clinical treatment strategy. In present study, we identified a novel tumor-suppressive lncRNA small nucleolar RNA host gene 10 (SNHG10) in EOC. Kaplan–Meier analysis and COX proportional hazard progression model showed that low expression of SNHG10 was correlated with a poor prognosis of EOC patients. Overexpressing SNHG10 suppressed the proliferation, colony formation, migration, and invasion of EOC cells. Furthermore, SNHG10 was predicted to sponge miR-200a-3p in EOC cells according to the LncBase v.2 experimental module. Then, the binding of SNHG10 and miR-200a-3p was confirmed by performing quantitative real-time PCR (qRT-PCR) and luciferase reporter assays. RNA immunoprecipitation (RIP) showed that SNHG10 and miR-200a-3p occupied the same Ago2 protein to form an RNA-induced silencing complex (RISC). By overlapping the results from the bioinformatics algorithms, tumor-suppressor bridging integrator-1 (BIN1) was found to be a main downstream target of the SNHG10/miR-200a-3p axis. Low expression of BIN1 in EOC tissues was detected by using immunohistochemistry (IHC). Besides, BIN1 and SNHG10 expression was positively correlated in EOC tissues. By performing miRNA rescue experiments, a SNHG10/miR-200a-3p/BIN1 axis and its promoting effects on malignant behaviors and epithelial–mesenchymal transition (EMT) process were verified in EOC cells. Moreover, SNHG10 overexpression significantly suppressed the tumorigenesis and EMT of EOC cells in vivo. Altogether, SNHG10 sponges miR-200a-3p to upregulate BIN1 and thereby exerting its tumor-suppressive effects in EOC. Therefore, the SNHG10/miR-200a-3p/BIN1 axis may act as a potential predictive biomarker and therapeutic target for treating EOC.

RP5-1148A21.3 (lncRP5) exerts oncogenic function in human ovarian carcinoma

Ovarian cancer (OC) is a fatal gynecological malignancy that is difficult to diagnose at early stages. Various long non-coding RNAs (lncRNAs) are aberrantly expressed in OC and exert regulatory effects on OC; however, the underlying mechanism requires in-depth investigation. This work is designed to explore the molecular regulatory axis of a newly identified lncRNA in OC, that is, lncRNA RP5-1148A21.3 (lncRP5). RT-qPCR shows lncRP5 is significantly upregulated in OC patients and cell lines, and it is mainly located in the cytoplasm of OC cells. The results of CCK-8, colony formation, and transwell assays demonstrate that overexpression of lncRP5 greatly contributes to malignant behaviors of OC cells, while inhibition of lncRP5 shows the opposite effects. Moreover, the binding relationship between lncRP5 and miR-545-5p is predicted by bioinformatics and is further verified by luciferase assay. Functionally, the regulatory effects of lncRP5 and miR-545-3p are negatively related; miR-545-5p serves as a tumor suppressor in OC. Further studies demonstrate that PTP4A1 is the target gene of miR-545-5p. Overexpression of PTP4A1 abrogates the inhibitory function of miR-545-5p on OC cell growth and metastasis. The lncRP5/miR-545-5p/PTP4A1 axis is subsequently demonstrated in vivo, and knockdown of lncRP5 notably inhibits tumor growth. This study provides a novel regulatory mechanism of OC, which may contribute to the diagnosis and therapy of OC.

Immune-Related Long Non-coding RNA Constructs a Prognostic Signature of Ovarian Cancer

Background

Since ovarian cancer leads to the poor prognosis in women all over the world, we aim to construct an immune-related lncRNAs signature to improve the survival of ovarian cancer patients.

Methods

Normal and cancer patient samples and corresponding clinical data of ovarian were obtained from The Genotype-Tissue Expression (GTEx) portal and The Cancer Genome Atlas (TCGA) database. The predictive signature was constructed by the lasso penalty Cox proportional hazard regression model. The division of different risk groups was accounting for the optimal critical value of the time-dependent Receiver Operating Characteristic (ROC) curve. Finally, we validated and evaluated the application of this prognostic signature based on the clinical factors, chemo-sensitivity and immune status of different risk groups.

Results

The signature was established from 145 DEirlncRNAs and can be shown as an independent prognostic risk factor with accurate prediction on overall survival in ovarian cancer patients. Further analysis on the application of the prognostic signature showed that patients with low-risk had a better sensitivity to chemotherapy and a higher immunogenicity.

Conclusion

We constructed and verified an effective signature based on DEirlncRNA pairs, which could predict the prognosis, drug sensitivity and immune status of ovarian cancer patients and promote the prognostic estimation and individualized treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12575-021-00161-9.

The miRNA mir-582-3p suppresses ovarian cancer progression by targeting AKT/MTOR signaling via lncRNA TUG1

Ovarian cancer (OC) is one of the most common malignancies of the female reproductive system. The miRNA miR-582-3p is associated with a variety of tumors, and the aim of this study was to investigate the role and mechanisms of miR-582-3p specifically in ovarian carcinogenesis and progression. Low expression of miR-582-3p was noted in OC tissue and cell lines, and lower expression of miR-582-3p correlated with lower overall survival in OC patients. Knockdown of miR-582-3p promoted the proliferation and migration of OC cells, while overexpression inhibited them. TUG1, a long non-coding RNA, was found to bind to miR-582-3p, and inhibition of lncRNA TUG1 decreased viability and migration and weakened the effect of miR-582-3p knockdown in OC cells. Implantation of OC cells with reduced miR-582-3p caused increased tumor growth, while lncRNA TUG1 knockdown suppressed tumor growth and relieved the impact of reduced miR-582-3p in vivo. Phosphorylation of AKT and mTOR were significantly enhanced with decreased miR-582-3p expression, but lncRNA TUG1 knockdown attenuated this trend in vitro and in vivo. The novel miR-582-3p represses the malignant properties of OC via the AKT/mTOR signaling pathway by targeting lncRNA TUG1. This axis may represent valuable prognostic biomarkers and therapeutic targets for OC.

lncRNA OR3A4 Promotes the Proliferation and Metastasis of Ovarian Cancer Through KLF6 Pathway

Aim: Ovarian cancer is a collaborative malignant tumor of the female reproductive system in clinical research. Some clinical studies have shown that OR3A4, which is a cancer-causing lncRNA, plays a major role in promoting the occurrence and development of a variety of tumors. And we also expressed the view that it expressed in ovarian tissue. However, the function of OR3A4 in ovarian cancer remains unclear. Methods and Results: To further verify the function of lncRNA OR3A4 in ovarian cancer, we established the xenograft model in the zebra fish. In this study, cells transformed with OR3A4 shRNA plasmids were transplanted into the zebra fish, and the cell proliferation and migration ability were significantly reduced compared to the empty vector. While knocking out OR3A4, we further downregulated its expression by siRNA of KLF6. Our study found that the knocked out OR3A4 resulted in a decrease in cell proliferation and migration level, which can be found in the downregulated expression of KLF6. We also verify the relationship between OR3A4 and circulating tumor cells in the zebra fish xenograft model, the results indicate that lncRNA OR3A4 may be involved in the resistance of ovarian cancer to complain. Conclusion: lncRNA OR3A4 promotes the proliferation and metastasis of ovarian cancer through the KLF6 pathway.

(In)Distinctive Role of Long Non-Coding RNAs in Common and Rare Ovarian Cancers

Rare ovarian cancers (ROCs) are OCs with an annual incidence of fewer than 6 cases per 100,000 women. They affect women of all ages, but due to their low incidence and the potential clinical inexperience in management, there can be a delay in diagnosis, leading to a poor prognosis. The underlying causes for these tumors are varied, but generally, the tumors arise due to alterations in gene/protein expression in cellular processes that regulate normal proliferation and its checkpoints. Dysregulation of the cellular processes that lead to cancer includes gene mutations, epimutations, non-coding RNA (ncRNA) regulation, posttranscriptional and posttranslational modifications. Long non-coding RNA (lncRNA) are defined as transcribed RNA molecules, more than 200 nucleotides in length which are not translated into proteins. They regulate gene expression through several mechanisms and therefore add another level of complexity to the regulatory mechanisms affecting tumor development. Since few studies have been performed on ROCs, in this review we summarize the mechanisms of action of lncRNA in OC, with an emphasis on ROCs.

MAFG-AS1/MAFG positive feedback loop contributes to cisplatin resistance in bladder urothelial carcinoma through antagonistic ferroptosis

Though promoting ferroptosis can reduce cisplatin resistance in tumor cells, ferroptosis and cisplatin resistance in bladder urothelial carcinoma (BUC) following long non-coding RNAs (lncRNAs) is largely unknown. Here, we found the highly expressed lncRNA MAF transcription factor G antisense RNA 1 (MAFG-AS1) in BUC, and its inhibition increased the sensitivity of BUC cells to cisplatin by promoting ferroptosis. Mechanically, binding to iron chaperone poly(rC)-binding protein 2 (PCBP2) facilitated the recruitments of MAFG-AS1 to deubiquitinase ubiquitin carboxyl-terminal hydrolase isozyme L5 (UCHL5), thus stabilizing PCBP2 protein itself. Then PCBP2 was confirmed to interact with ferroportin 1 (FPN1), an iron export protein, leading to inhibition of ferroptosis. Moreover, the expression of MAFG-AS1 was regulated by the transcriptional factor MAFG. Interestingly, MAFG-AS1 stimulated MAFG transcription by recruiting histone acetyltransferase p300 (EP300) to promote the histone 3 at lysine 27 (H3K27ac) at genomic locus of MAFG, forming a MAFG-AS1/MAFG positive feedback loop. In patient samples, higher expression of MAFG-AS1 and MAFG in BUC tissues was significantly correlated with T status and N status, such that MAFG-AS1, MAFG, and the combination of the two were independent prognostic indicators and chemotherapy sensitivity predictive biomarkers for BUC patients. These findings suggest that inhibition of MAFG-AS1 and MAFG can increase the sensitivity of BUC cells to cisplatin through promoting ferroptosis, indicating the novel chemotherapy sensitivity biomarkers and therapeutic target for BUC.

Development and validation of a novel N6-methyladenosine (m6A)-related multi- long non-coding RNA (lncRNA) prognostic signature in pancreatic adenocarcinoma

Accumulating evidence has unveiled the pivotal roles of N6-methyladenosine (m6A) in pancreatic adenocarcinoma (PAAD). However, there are not many researches to predict the prognosis of PAAD using m6A-related long non-coding RNAs (lncRNAs). Raw data from The Cancer Genome Atlas (TCGA), International Cancer Genome Consortium (ICGC), and the Genotype-Tissue Expression project (GTEx) were utilized to comprehensively analyze the expression and prognostic performances of 145 m6A-related lncRNAs in PAAD and to develop and validate a novel m6A-related multi-lncRNA prognostic signature (m6A-LPS) for PAAD patients. In total, 57 differentially expressed m6A-related lncRNAs with prognostic values were identified. Based on LASSO-Cox regression analysis, m6A-LPS was constructed and verified by using five-lncRNA expression profiles for TCGA and ICGC cohorts. PAAD patients were then divided into high- and low-risKBIE_A_1933868k subgroups with different clinical outcomes according to the median risk score; this was further verified by time-dependent receiver operating characteristic curves. Risk scores were significantly associated with clinical parameters such as histological grade and cancer status among PAAD patients. A nomogram consisting of risk score, grade, and cancer status was generated to predict the survival probability of PAAD patients, as also demonstrated by calibration curves. Discrepancies in cellular processes, signaling pathways, and immune status between the high- and low-risk subgroups were investigated by functional and single-sample gene set enrichment analyses. In conclusion, the novel m6A-LPS for PAAD patients was developed and validated, which might provide new insight into clinical decision-making and precision medicine.

Screening and Identification of an Immune-Associated lncRNA Prognostic Signature in Ovarian Carcinoma: Evidence from Bioinformatic Analysis

Backgrounds

The dysregulated long noncoding RNAs (lncRNAs) have been described to be crucial regulators in the progression of ovarian carcinoma. The infiltration status of immune cells is also related to the clinical outcomes in ovarian carcinoma. The present research is aimed at constructing an immune-associated lncRNA signature with potential prognostic value for ovarian carcinoma patients.

Methods

We obtained 379 ovarian carcinoma cases with available clinical data and transcriptome data from The Cancer Genome Atlas database to evaluate the infiltration status of immune cells, thereby generating high and low immune cell infiltration groups. According to the expression of the immune-associated lncRNA signature, the risk score of each case was calculated. The high- and low-risk groups were classified using the median risk score as threshold.

Results

A total of 169 immune-associated lncRNAs that differentially expressed in ovarian carcinoma were included. According to the Lasso regression analysis and Cox univariate and multivariate analyses, 5 immune-associated lncRNAs, including AC134312.1, AL133467.1, CHRM3-AS2, LINC01722, and LINC02207, were identified as a predictive signature with significant prognostic value in ovarian carcinoma. The following Kaplan-Meier analysis, ROC analysis, and Cox univariate and multivariate analyses further suggested that the predicted signature may be an independent prognosticator for patients with ovarian carcinoma. The following gene set enrichment analysis showed that this 5 immune-associated lncRNAs signature was significantly related to the hedgehog pathway, basal cell carcinoma, Wnt signaling pathway, cytokine receptor interaction, antigen processing and presentation, and T cell receptor pathway.

Conclusion

: This study suggested a predictive model with 5 immune-associated lncRNAs that has an independent prognostic value for ovarian carcinoma patients.

Down-regulation of long non-coding RNA antisense non-coding RNA in the INK4 locus suppresses OVCAR-3 cells proliferation and induction of apoptosis by Wnt/β -catenin

OBJECTIVES

Ovarian cancer is a lethal gynecological malignancy. Long non-coding RNA antisense non-coding RNA in the INK4 locus (lncRNA ANRIL) was reported to have a critical role in cancer advancement. The ANRIL-mediated oncogenic underlying molecular mechanisms are not fully understood in ovarian cancer. We aimed to study ANRIL silencing effects on the proliferation and apoptosis of OVCAR-3 cells.

METHODS

The ANRIL was Knockdown by transfection of OVCAR-3 cells with si-RNA against ANRIL. MTT assay and cell death ELISA kit were used to evaluate cellular proliferation and apoptosis. The expression levels of ANRIL, pro-and anti-apoptotic genes were assessed using q-RT-PCR. Western blotting was used to assess Wnt/β-catenin signalling pathway.

KEY FINDINGS

ANRIL down-regulating in OVCAR-3 cell lines resulted in significant inhibition of cellular proliferation, apoptosis induction, as well as suppression of cellular invasion. Besides, knockdown of ANRIL led to pro-apoptotic genes up-regulation, Bad and Bax and anti-apoptotic genes down-regulation, Bid and Bcl-2. More importantly, we observed that ANRIL inhibition suppressed the vital components expression of the Wnt/β-catenin cascade.

CONCLUSION

Our findings showed that down-regulation of lncRNA ANRIL resulted in the effective suppression of OVCAR-3 cell proliferation and invasion and induction of apoptosis by preventing Wnt/β-catenin signal transduction.

The RNA-Binding Protein CELF2 Inhibits Ovarian Cancer Progression by Stabilizing FAM198B

An increasing number of studies have clarified the functional roles of RNA-binding proteins (RBPs) in driving post-transcriptional mechanisms of cancer progression. In this study, we integrated data from the RBP database and Gene Expression Omnibus (GEO) data with RNA sequencing (RNA-seq) data from 10 ovarian cancer tissues and 8 normal ovarian tissues and identified an RBP, CUGBP- and ETR-3-like family 2 (CELF2). We found that CELF2 expression was downregulated in ovarian cancer and positively correlated with the overall survival (OS) and progression-free survival (PFS) of patients with ovarian cancer. Altered CELF2 expression led to changes in the proliferation, migration, and invasion of ovarian cancer cells in vitro and in vivo. CELF2 expression increased the stability of its target, FAM198B, by binding to AU/U-rich elements (AREs) in the 3' untranslated region (3' UTR). FAM198B knockdown restored the CELF2-mediated suppression of proliferation and migration. We also found that CELF2/FAM198B may repress ovarian cancer progression by inhibiting the mitogen-activated protein kinase/extracellular-regulated protein kinase (MAPK/ERK) signaling pathway. Finally, a curcumin-induced increase in CELF2 expression resulted in increased ovarian cancer cell sensitivity to cisplatin. Our study elucidated a novel mechanism by which the CELF2/FAM198B axis regulates proliferation and metastasis in ovarian cancer, providing novel, potential therapeutic targets for ovarian cancer.

Long Noncoding RNAs in Gastrointestinal Cancer: Tumor Suppression Versus Tumor Promotion

Approximately 80% of the human genome harbors biochemical marks of active transcription that its majority transcribes to noncoding RNAs, namely long noncoding RNAs (lncRNAs). LncRNAs are heterogeneous RNA transcripts that regulate critical biological processes such as cell survival and death. They involve in the progression of different cancers by affecting transcriptional and post-transcriptional modifications as well as epigenetic control of numerous tumor suppressors and oncogenes. Recent findings show that aberrant expression of lncRNAs is associated with tumor initiation, progression, invasion, and overall survival of patients with gastrointestinal (GI) cancers. Some lncRNAs play as tumor suppressors in all GI cancers, but others play as tumor promoters. However, some other lncRNAs might function as a tumor suppressor in one GI cancer, but as a tumor promoter in another GI cancer type. This fact highlights possible context dependency of the expression patterns and roles of at least some lncRNAs in GI cancer development and progression. Here, we review the functional relation of lncRNAs involved in the development and progression of GI cancer by focusing on their roles as tumor suppressor and tumor promoter genes.

LINC00494 Promotes Ovarian Cancer Development and Progression by Modulating NFκB1 and FBXO32

BACKGROUND

Ovarian cancer represents one of the most frequent gynecological cancers and is significant cause of death for women around the world. Long non-coding RNAs (lncRNAs) are recognized as critical governors of gene expression during carcinogenesis, but their effects on the occurrence and development of ovarian cancer require further investigation. In this report, we characterized LINC00494 as a novel oncogenic lncRNA in ovarian cancer.

METHODS

Bioinformatics analysis predicted potential interactions among LINC00494, NFκB1, and FBXO32 in ovarian cancer, which were tested by dual-luciferase reporter assay, RNA pull-down, RIP, and ChIP assay. Cancer cells were transfected with relevant treated plasmids, followed by scratch and Transwell assays. The treated cells were injected into nude mice to establish a xenograft model for testing effects of LINC00494 and its target gene in vivo.

RESULTS

LINC00494 and NFκB1 were highly expressed whereas FBXO32 had low expression in ovarian cancer cells and tissues. LINC00494 was found to bind NFκB1 and increase its activity, while NFκB1 was enriched at the FBXO32 promoter region, where it acted to reduce FBXO32 transcription. Overexpression of LINC00494 elevated NFκB1 expression and enhanced cell migration, invasion and tumorigenesis, but additional overexpression of FBXO32 interfered with the tumorgenicity of ovarian cancer cells in vitro and in vivo.

CONCLUSION

Our work demonstrated that LINC00494 promoted ovarian cancer progression by modulating FBXO32 via binding with the transcription factor NFκB1. These results provided new insight into the mechanism of ovarian cancer pathogenesis and suggested new therapeutic targets.

Cell Proliferation Is Strongly Associated with the Treatment Conditions of an ER Stress Inducer New Anti-Melanoma Drug in Melanoma Cell Lines

HA15 is a new anti-melanoma drug that triggers endoplasmic reticulum (ER) stress and causes deleterious effects on melanoma cell viability due to autophagy and apoptosis, regardless of driver mutations or drug resistance. In this study, we investigated the effect of HA15 on the viability/proliferation of BRAFV600E-mutant melanoma cells using different culture conditions. In contrast to the published data, we did not detect significant melanoma cell death under normal culture conditions using HA15 treatment. Indeed, only cells that were cultured under long-term starvation conditions were sensitive to the drug. Quantitative measurements of ER stress and autophagy markers showed that the compound HA15 does not trigger stress alone but synergistically enhances ER stress under starvation conditions. Importantly, we observed that the viability of normal melanocytes decreased significantly with treatment, even at low HA15 concentrations. Finally yet importantly, we were able to generate HA15-resistant cell lines, which failed by Cerezo et al. In summary, HA15 only influences the viability of cells that are starved for several hours before and during treatment. However, this in vitro setting is far from the in vivo conditions. In addition, our data clearly show that melanoma cells can acquire HA15 resistance. Further studies are needed to prove that HA15 is an effective anti-cancer agent.

Identification of Potential Prognostic Competing Triplets in High-Grade Serous Ovarian Cancer

Increasing lncRNA-associated competing triplets were found to play important roles in cancers. With the accumulation of high-throughput sequencing data in public databases, the size of available tumor samples is becoming larger and larger, which introduces new challenges to identify competing triplets. Here, we developed a novel method, called LncMiM, to detect the lncRNA–miRNA–mRNA competing triplets in ovarian cancer with tumor samples from the TCGA database. In LncMiM, non-linear correlation analysis is used to cover the problem of weak correlations between miRNA–target pairs, which is mainly due to the difference in the magnitude of the expression level. In addition, besides the miRNA, the impact of lncRNA and mRNA on the interactions in triplets is also considered to improve the identification sensitivity of LncMiM without reducing its accuracy. By using LncMiM, a total of 847 lncRNA-associated competing triplets were found. All the competing triplets form a miRNA–lncRNA pair centered regulatory network, in which ZFAS1, SNHG29, GAS5, AC112491.1, and AC099850.4 are the top five lncRNAs with most connections. The results of biological process and KEGG pathway enrichment analysis indicates that the competing triplets are mainly associated with cell division, cell proliferation, cell cycle, oocyte meiosis, oxidative phosphorylation, ribosome, and p53 signaling pathway. Through survival analysis, 107 potential prognostic biomarkers are found in the competing triplets, including FGD5-AS1, HCP5, HMGN4, TACC3, and so on. LncMiM is available at https://github.com/xiaofengsong/LncMiM.

Long Noncoding RNA E2F4as Promotes Progression and Predicts Patient Prognosis in Human Ovarian Cancer

Simple Summary

LncRNA is a promising biomarker that predicts the prognosis of a variety of cancers, but the important role of E2F4antisense lncRNA in cancer remains unclear. Therefore, we decided to explore the role of E2F4as lncRNA in the blood of an ovarian cancer patient. We found that E2F4as was highly expressed in ovarian cancer patients, and that the higher the expression of E2F4as, the worse the patient’s prognosis. In addition, we observed that downregulation of E2F4as in ovarian cancer cells reduced cell proliferation, invasion and migration, decreased expression of EMT-related genes, and increased apoptosis. These findings suggest that E2F4as may be a predictive biomarker in the blood of ovarian cancer patients, and have shown the potential to promote tumor aggression through EMT-related mechanisms.

Abstract

(1) Background: LncRNAs could be a promising biomarker to predict the prognosis of various cancers. The significance of E2F4antisense lncRNA remains unclear in cancer. In this study, we examined the expression level of E2F4as in the serum of ovarian cancer patients and the functional role of E2F4as. (2) Methods: Serum samples were obtained from 108 OC patients and 32 normal patients to measure the expression of E2F4as in the serum. Ovarian cancer cells were used to investigate the role of E2F4as in cell proliferation, invasion, migration and apoptosis, and the expression of E2F4as was knocked down using RNA interference. In addition, E2F4as knockdown cell lines were used in in vivo experiments. (3) Results: The expression of E2F4as was significantly higher in the serum of OC patients than in that of control patients (p < 0.05). The knockdown of E2F4as in ovarian cancer cells led to a decrease in cell proliferation, invasion and migration and an increase in apoptosis. E2F4as knockdown also reduced the expression of epithelium–mesenchymal metastasis (EMT) genes. (4) Conclusion: These findings highlight the clinical significance of E2F4as in predicting the prognosis of OC patients and suggest its potential in promoting tumour aggressiveness by the regulation of EMT-related mechanisms.

LncRNAs in Ovarian Cancer Progression, Metastasis, and Main Pathways: ceRNA and Alternative Mechanisms

Ovarian cancer (OvCa) develops asymptomatically until it reaches the advanced stages with metastasis, chemoresistance, and poor prognosis. Our review focuses on the analysis of regulatory long non-coding RNAs (lncRNAs) competing with protein-coding mRNAs for binding to miRNAs according to the model of competitive endogenous RNA (ceRNA) in OvCa. Analysis of publications showed that most lncRNAs acting as ceRNAs participate in OvCa progression: migration, invasion, epithelial-mesenchymal transition (EMT), and metastasis. More than 30 lncRNAs turned out to be predictors of survival and/or response to therapy in patients with OvCa. For a number of oncogenic (CCAT1, HOTAIR, NEAT1, and TUG1 among others) and some suppressive lncRNAs, several lncRNA/miRNA/mRNA axes were identified, which revealed various functions for each of them. Our review also considers examples of alternative mechanisms of actions for lncRNAs besides being ceRNAs, including binding directly to mRNA or protein, and some of them (DANCR, GAS5, MALAT1, and UCA1 among others) act by both mechanisms depending on the target protein. A systematic analysis based on the data from literature and Panther or KEGG (Kyoto Encyclopedia of Genes and Genomes) databases showed that a significant part of lncRNAs affects the key pathways involved in OvCa metastasis, EMT, and chemoresistance.

CircASH2L Promotes Ovarian Cancer Tumorigenesis, Angiogenesis, and Lymphangiogenesis by Regulating the miR-665/VEGFA Axis as a Competing Endogenous RNA

Ovarian cancer is the leading cause of gynecologic cancer-related deaths. Emerging research has revealed a close relationship between circular RNAs (circRNAs) and ovarian cancer development, metastasis, and prognosis. The objective of our research was to further explore the relationship between circASH2L and ovarian cancer. Quantitative real-time polymerase chain reaction was used to detect the differential expression of circRNAs between normal ovaries and ovarian cancer tissues. The impact of circASH2L on the proliferation, invasion, and tumorigenicity of ovarian cancer cells was evaluated using gain- and loss-of-function experiments. The molecular mechanisms of circASH2L function were investigated using bioinformatics analysis, RNA fluorescence in situ hybridization, western blots, and dual-luciferase reporter assays. The results showed that circASH2L was remarkably upregulated in ovarian cancer. The invasion and growth of ovarian cancer cells were suppressed by circASH2L knockdown in vitro, and downregulation of circASH2L restrained both angiogenesis and lymphangiogenesis of tumor xenografts in vivo. Furthermore, circASH2L was mostly distributed in the cytoplasm, where it competes with vascular endothelial growth factor A (VEGFA) for binding to miR-665. These findings indicate that circASH2L has an oncogenic function in ovarian cancer. In conclusion, circASH2L plays a critical role in regulating ovarian cancer cell tumorigenesis, angiogenesis, and lymphangiogenesis through the miR-665/VEGFA axis and, therefore, is a possible candidate target for ovarian cancer treatment.

LINC00452 promotes ovarian carcinogenesis through increasing ROCK1 by sponging miR-501-3p and suppressing ubiquitin-mediated degradation

Ovarian cancer refers to all sorts of cancerous growth that starts from the ovary. Dysregulation of long non-coding RNAs (lncRNAs) is associated with ovarian cancer development and progression. Cellular expression and localization of LINC00452 in ovarian cancer cells were detected by qPCR and FISH. The roles of LINC00452 in ovarian carcinogenesis were characterized by MTT, transwell and colony-formation assays in vitro as well as xenograft mouse model. The underlying mechanism was explored by microarray, RIP, Co-IP and luciferase reporter assays. This study identified a novel lncRNA LINC00452 being elevated in both ovarian cancer cells and tumor tissues in patients. Such aberrant expression of LINC00452 was negatively correlated with relapse-free survival of ovarian cancer patients. Overexpression of LINC00452 potentiated CaOV3 cell viability, migration and invasion in vitro as well as xenograft tumor growth in vivo. Evidence from the current study suggests that the carcinogenicity of LINC00452 is partially due to competitive sponging of miR-501-3p followed with release of repression on the ROCK1, a key effector in Rho signaling pathway. Irrespective of its miRNA sponge function, LINC00452 is capable of preventing ROCK1 protein from ubiquitin/proteasome-mediated degradation via their mutual physical interaction. Our study makes LINC00452 a potential therapeutic target for ovarian cancer.

Noncoding RNA (ncRNA) Profile Association with Patient Outcome in Epithelial Ovarian Cancer Cases

Ovarian cancer (OC) is the second most frequent type of gynecological cancers worldwide. In the past decades, the development of novel diagnostic and prognostic biomarkers available for OC has been limited, reflecting by the lack of specificity of such markers or very costly management. Microarray expression profiling has shown very effective results in exploring new molecular markers for patients with OC. Nonetheless, most screenings are focused on mutations or expression of molecules that are translated into proteins, corresponding to only 2% of the total human genome. In order to account for the vast majority of transcripts, in the present exploratory study, we assessed the expression levels of a comprehensive panel of noncoding RNA in different subtypes of OC. We further evaluated their association with patient overall survival (OS) and aggressive forms of the disease, such as tumor type, stage, and chemotherapy resistance. By microarray profiling in a total of 197 epithelial OC patients (162 serous carcinomas, 15 endometrioid carcinomas, 11 mucinous carcinomas, and 9 clear cell carcinomas), we found two candidates, SNORA68 and SNORD74, which associated with OS and poor clinicopathological features. The overexpression of those two targets combined was correlated with shorter OS and progression-free survival. That association was further observed to correlate with a more aggressive form of the disease. Overall, the results indicate that a panel comprised of SNORA68 and SNORD74 may be clinically relevant, where patients could be offered a more individualized, targeted follow-up, given its further validation on future prospective clinical studies.

Construction of novel mRNA-miRNA-lncRNA regulatory networks associated with prognosis of ovarian cancer

Background: Ovarian cancer (OC) is the most lethal malignancy in the female reproductive system. Growing evidences demonstrates that competing endogenous RNA (ceRNA) network play crucial roles in the occurrence and progression of tumors. Therefore, we aimed to explore and identify novel mRNA-miRNA-lncRNA ceRNA networks associated with prognosis of OC. Methods: The differentially expressed gene (DEGs) of four expression profiles datasets (GSE5438, GSE40595, GSE38666 and GSE26712) were collected from Gene Expression Omnibus (GEO) database and analyzed with NetworkAnalyst. Intersection of DEGs were further employed for Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway analysis. Protein-protein interaction (PPI) network and hub genes of DEGs were also identified. The expression levels and survival analysis of the hub genes in OC and their upstream miRNAs and lncRNAs were performed by various bioinformatics databases. More importantly, ceRNA networks were constructed based on mRNA-miRNA-lncRNA in OC. Results: A total of 178 DEGs including 38 upregulated and 140 downregulated genes from intersected DEGs of four expression profiles were identified in OC. Functional enrichment analysis suggested that the commonly DEGs were enriched in regulating enzyme inhibitor activity, glycosaminoglycan and G protein-coupled receptor binding, cell morphogenesis, and involved in pathways including metabolic process, proteoglycans in cancer. Top 10 hub genes with higher connectivity degree were selected for subsequent expression and prognosis analysis. After take expression levels and prognostic roles of hub genes and their upstream miRNAs and lncRNAs in OC into consideration, 2 mRNAs (TACC3 and CXCR4), 2 miRNAs (hsa-miR-425-5p and hsa-miR-146a-5p) and 3 lncRNAs (FUT8-AS1, LINC00665 and LINC01535) were significantly associated with the poor prognosis of OC. The mRNA-miRNA-lncRNA networks (TACC3-hsa-miR-425-5p-FUT8-AS1 and CXCR4-hsa-miR-146a-5p-LINC00665/LINC01535) were eventually constructed in OC based on ceRNA mechanism. Conclusion: We successfully constructed novel ceRNA network associated with the prognosis of ovarian cancer, which may provide a new strategy for early diagnosis and therapeutic intervention of OC.

Long non‑coding RNA NEAT1 promotes ovarian cancer cell invasion and migration by interacting with miR‑1321 and regulating tight junction protein 3 expression

Previous studies have reported that long non‑coding RNAs (lncRNAs) have a significant role in the metastasis of tumors, including ovarian cancer (OC). The aim of the present study was to demonstrate the function and working mechanism of lncRNA nuclear enriched abundant transcript 1 (NEAT1) in OC. The expressions of NEAT1 in OC were measured by reverse transcription‑quantitativePCR (RT‑qPCR). The effects of NEAT1 on cell proliferation, invasion, migration and epithelial‑mesenchymal transition (EMT) were detected by Cell Counting Kit‑8, transwell and wound healing assays, and western blotting. Dual‑luciferase reporter assays were performed to confirm the correlated between NEAT and miR‑1321, miR‑1321 and TJP3. The effect of NEAT1 on miR‑1321 and TJP3 was confirmed by RT‑qPCR and western blotting. Elevated expression of NEAT1 was observed in OC cell lines, and NEAT1 expression was found to be positively related to the expression of tight junction protein 3 (TJP3), which is important in cancer development. Moreover, the present results indicated that NEAT1 and TJP3 expression levels were negatively correlated with microRNA (miR)‑1321 expression in OC. Knockdown of NEAT1 attenuated the migration and invasion of OC cells, as well as increased miR‑1321 expression and in turn led to the reduction of TJP3. Thus, the present study demonstrated that NEAT1 regulates TJP3 expression by sponging miR‑1321 and enhances the epithelial‑mesenchymal transition, invasion and migration of OC cells. Overall, the present study identified the function and mechanism of NEAT1 in OC, suggesting that NEAT1 may be a promising therapeutic target for OC metastasis.

Long non‑coding RNA MCM3AP‑AS1 drives ovarian cancer progression via the microRNA‑143‑3p/TAK1 axis

The long non‑coding RNA (lncRNA) MCM3AP antisense 1 (MCM3AP‑AS1) has previously been shown to be a key regulator of multiple types of cancer; however whether it is important in the context of ovarian cancer (OC) is uncertain. The present study determined that MCM3AP‑AS1 expression in samples from patients with OC was significantly increased, and was associated with tumor stage, presence of lymph node metastases and poorer overall survival. The role of this lncRNA was investigated in vitro, and it was observed that knockdown of MCM3AP‑AS1 impaired OC cell proliferation, migration and colony formation. Similarly, it disrupted tumor growth in vivo. The present study further determined that MCM3AP‑AS1 was able to directly interact with microRNA (miRNA or miR)‑143‑3p as a competing endogenous (ce)RNA for this miRNA, thereby regulating the expression of transforming growth factor‑β‑activated kinase 1 (TAK1), a known target of miR‑143‑3p in OC. Consistent with this, inhibition of miR‑143‑3p was sufficient to partially reverse the effects of MCM3AP‑AS1‑knockdown, which inhibited the proliferation, migration and invasion of OC cells. Together, these results indicate that MCM3AP‑AS1 serves as an oncogenic lncRNA in OC by binding to miR‑143‑3p and thereby promoting TAK1 expression, and suggest that this lncRNA may be a possible target for therapy in OC.

The Interplay between Long Noncoding RNAs and Proteins of the Epigenetic Machinery in Ovarian Cancer

Comprehensive large-scale sequencing and bioinformatics analyses have uncovered a myriad of cancer-associated long noncoding RNAs (lncRNAs). Aberrant expression of lncRNAs is associated with epigenetic reprogramming during tumor development and progression, mainly due to their ability to interact with DNA, RNA, or proteins to regulate gene expression. LncRNAs participate in the control of gene expression patterns during development and cell differentiation and can be cell and cancer type specific. In this review, we described the potential of lncRNAs for clinical applications in ovarian cancer (OC). OC is a complex and heterogeneous disease characterized by relapse, chemoresistance, and high mortality rates. Despite advances in diagnosis and treatment, no significant improvements in long-term survival were observed in OC patients. A set of lncRNAs was associated with survival and response to therapy in this malignancy. We manually curated databases and used bioinformatics tools to identify lncRNAs implicated in the epigenetic regulation, along with examples of direct interactions between the lncRNAs and proteins of the epigenetic machinery in OC. The resources and mechanisms presented herein can improve the understanding of OC biology and provide the basis for further investigations regarding the selection of novel biomarkers and therapeutic targets.

Novel role of lncRNA CHRF in cisplatin resistance of ovarian cancer is mediated by miR-10b induced EMT and STAT3 signaling

Ovarian Cancer (OC) is a highly lethal gynecological cancer which often progresses through acquired resistance against the administered therapy. Cisplatin is a common therapeutic for the treatment of OC patients and therefore it is critical to understand the mechanisms of resistance against this drug. We studied a paired cell line consisting of parental and cisplatin resistant (CR) derivative ES2 OC cells, and found a number of dysregulated lncRNAs, with CHRF being the most significantly upregulated lncRNA in CR ES2 cells. The findings corroborated in human patient samples and CHRF was significantly elevated in OC patients with resistant disease. CHRF was also found to be elevated in patients with liver metastasis. miR-10b was found to be mechanistically involved in CHRF mediated cisplatin resistance. It induced resistance in not only ES2 but also OVCAR and SKOV3 OC cells. Induction of epithelial-to-mesenchymal-transition (EMT) and activation of STAT3 signaling were determined to be the mechanisms underlying the CHRF-miR-10b axis-mediated cisplatin resistance. Down-regulation of CHRF reversed EMT, STAT3 activation and the resulting cisplatin resistance, which could be attenuated by miR-10b. The results were also validated in an in vivo cisplatin resistance model wherein CR cells were associated with increased tumor burden, CHRF downregulation associated with decreased tumor burden and miR-10b again attenuated the CHRF downregulation effects. Our results support a novel role of lncRNA CHRF in cisplatin resistance of OC and establish CHRF-miR-10b signaling as a putative therapeutic target for sensitizing resistant OC cells.

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.

The Biological and Clinical Role of the Long Non-Coding RNA LOC642852 in Ovarian Carcinoma

The objective of the present study was to analyze the biological and clinical role of the long non-coding RNA LOC642852 in ovarian carcinoma (OC). LOC642852 expression was analyzed in seven OC cell lines (OVCAR-3, OVCAR-8, OVCA 433, OVCA 429, OC 238, DOV13, ES-2) and 139 high-grade serous carcinoma (HGSC) specimens (85 effusions, 54 surgical specimens). Following LOC642852 knockout (KO) using the CRISPR/Cas9 system, OVCAR-8 HGSC cells were analyzed for spheroid formation, migration, invasion, proliferation, matrix metalloproteinase (MMP) activity, and expression of cell signaling proteins. OVCAR-8 cells with LOC642852 KO were significantly less motile and less invasive compared to controls, with no differences in spheroid formation, proliferation, or matrix metalloproteinase (MMP) activity. Total Akt and Erk levels were comparable in controls and KO cells, but their phosphorylation was significantly increased in the latter. In clinical specimens, LOC642852 was overexpressed in ovarian tumors and omental/peritoneal metastases compared to effusion specimens (p = 0.013). A non-significant trend for shorter overall (p = 0.109) and progression-free (p = 0.056) survival was observed in patients with HGSC effusions with high LOC642852 levels. Bioinformatics analysis showed potential roles for LOC642852 as part of the TLE3/miR-221-3p ceRNA network and in relation to the FGFR3 protein. In conclusion, LOC642852 inactivation via CRISPR/Cas9 affects cell signaling, motility, and invasion in HGSC cells. LOC642852 is differentially expressed in HGSC cells at different anatomical sites. Its potential role in regulating the TLE3/miR-221-3p ceRNA network and FGFR3 merits further research.

Identification of aberrantly expressed long non-coding RNAs in ovarian high-grade serous carcinoma cells

PURPOSE

To identify the aberrantly expressed long non-coding RNAs (lncRNAs) in ovarian high-grade serous carcinoma (HGSC).

METHODS

Total RNA was isolated in HGSC cell lines, ovarian surface epithelial cells, and normal ovaries. Aberrantly expressed lncRNAs in HGSC were identified by PCR array, which analyzes 84 kinds of lncRNAs. To infer their functions, HGSC cell lines with different levels of expression of the identified lncRNAs were established, and then, activities of proliferation, migration, and apoptosis were examined. Expression levels of the identified lncRNAs were also examined in multiple ovarian HGSC tissues.

RESULTS

Ten aberrantly expressed lncRNAs, six upregulated and four downregulated, were identified in the HGSC cell lines. The authors established four HGSC cell lines: in two of the cell lines, one of the upregulated lncRNAs was knocked down, and in two other cell lines, one of the downregulated lncRNAs (MEG3 and POU5F1P5) was overexpressed. Migration activities were inhibited in the HGSC cell lines overexpressing MEG3 or POU5F1P5 while there were no differences in proliferation and apoptosis between the established and control cell lines. The four lncRNAs downregulated in the HGSC cell lines were also observed to be downregulated in ovarian HGSC tissues.

CONCLUSION

The authors identified four downregulated lncRNAs in ovarian HGSC.

Long non-coding RNA PVT1-mediated miR-543/SERPINI1 axis plays a key role in the regulatory mechanism of ovarian cancer

PURPOSE

To investigate the regulation mechanism of long non-coding RNA (lncRNA) plasmocytoma variant translocation 1 (PVT1) in ovarian cancer (OC).

METHODS

The levels of PVT1, microRNA (miR)-543, serpin peptidase inhibitor-clade I (neuroserpin)-member 1 (SERPINI1) in OC tissues and OVCAR-3, A2780, TOV-112D of OC cell lines were detected by quantitative real-time PCR (qRT-PCR) and Western Blot (WB). Cell proliferation, migration, invasion, apoptosis and the regulatory relationship between genes and target genes were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), Transwell, flow cytometry and dual luciferase reporter (DLR). The OC patients were followed up for 5 years to analyze the relationship between PVT1 and 5-year overall survival (OS).

RESULTS

In contrast with miR-543, PVT1 and SERPINI1 were highly expressed in OC tissues and cell lines, and high levels of PVT1 were significantly associated with lower 5-year OS of patients. Down-regulating PVT1 not only inhibited the malignant proliferation, migration and invasion of OC cells, but promoted cell apoptosis. PVT1 regulated miR-543 in a targeted manner, and its overexpression could attenuate the anticancer effect of miR-543 on OC cells. In addition, miR-543 also directly targeted SERPINI1, and miR-543 knockdown weakened the inhibitory effect of down-regulated SERPINI1 on OC progression. Furthermore, we found that PVT1 acted as a competitive endogenous RNA to sponge miR-543, thereby regulating the expression of SERPINI1.

CONCLUSION

PVT1 can mediate the molecular mechanism of OC by miR-543/SERPINI1 axis regulatory network, which is a new therapeutic direction for OC.

Long noncoding RNAs in endometriosis: Biological functions, expressions, and mechanisms

Endometriosis refers to a benign chronic gynecological disorder, and is defined as the ectopic growth of endometrium in pelvic cavity. Endometriosis affects about 10% of reproductive-aged women. Unfortunately, the pathogenesis of endometriosis remains obscure, and the disease witnesses a lack of effective therapy approaches. Therefore, more research needs to be performed to throw light on endometriosis, its pathogenesis, and therapy. Long noncoding RNAs (lncRNAs), which are defined as functional cellular RNA longer than 200 nucleotides, have been implicated in many chronic disorders. It has been suggested that lncRNAs are closely related to the endometriosis process. Nevertheless, the molecular mechanisms by which lncRNAs associate with endometriosis should be elucidated more detailed. In our brief review, we first exhibit the aberrant lncRNAs expression in endometriosis. Then, we talk about the molecular mechanisms underlying lncRNAs in endometriosis. Finally, we also present the potential of lncRNAs as biomarkers for endometriosis.

The functional role of long noncoding RNA in resistance to anticancer treatment

Chemotherapy is one of the fundamental methods of cancer treatment. However, drug resistance remains the main cause of clinical treatment failure. We comprehensively review the newly identified roles of long noncoding RNAs (lncRNAs) in oncobiology that are associated with drug resistance. The expression of lncRNAs is tissue-specific and often dysregulated in human cancers. Accumulating evidence suggests that lncRNAs are involved in chemoresistance of cancer cells. The main lncRNA-driven mechanisms of chemoresistance include regulation of drug efflux, DNA damage repair, cell cycle, apoptosis, epithelial-mesenchymal transition (EMT), induction of signaling pathways, and angiogenesis. LncRNA-driven mechanisms of resistance to various antineoplastic agents have been studied extensively. There are unique mechanisms of resistance against different types of drugs, and each mechanism may have more than one contributing factor. We summarize the emerging strategies that can be used to overcome the technical challenges in studying and addressing lncRNA-mediated drug resistance.

Knowledge-based analyses reveal new candidate genes associated with risk of hepatitis B virus related hepatocellular carcinoma

BACKGROUND

Recent genome-wide association studies (GWASs) have suggested several susceptibility loci of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) by statistical analysis at individual single-nucleotide polymorphisms (SNPs). However, these loci only explain a small fraction of HBV-related HCC heritability. In the present study, we aimed to identify additional susceptibility loci of HBV-related HCC using advanced knowledge-based analysis.

METHODS

We performed knowledge-based analysis (including gene- and gene-set-based association tests) on variant-level association p-values from two existing GWASs of HBV-related HCC. Five different types of gene-sets were collected for the association analysis. A number of SNPs within the gene prioritized by the knowledge-based association tests were selected to replicate genetic associations in an independent sample of 965 cases and 923 controls.

RESULTS

The gene-based association analysis detected four genes significantly or suggestively associated with HBV-related HCC risk: SLC39A8, GOLGA8M, SMIM31, and WHAMMP2. The gene-set-based association analysis prioritized two promising gene sets for HCC, cell cycle G1/S transition and NOTCH1 intracellular domain regulates transcription. Within the gene sets, three promising candidate genes (CDC45, NCOR1 and KAT2A) were further prioritized for HCC. Among genes of liver-specific expression, multiple genes previously implicated in HCC were also highlighted. However, probably due to small sample size, none of the genes prioritized by the knowledge-based association analyses were successfully replicated by variant-level association test in the independent sample.

CONCLUSIONS

This comprehensive knowledge-based association mining study suggested several promising genes and gene-sets associated with HBV-related HCC risks, which would facilitate follow-up functional studies on the pathogenic mechanism of HCC.

Comprehensive analysis of aberrantly expressed long non‑coding RNAs, microRNAs, and mRNAs associated with the competitive endogenous RNA network in cervical cancer

Cervical cancer is a common malignant disease that poses a serious health threat to women worldwide. Growing research efforts have focused on protein‑coding and non‑coding RNAs involved in the tumorigenesis and prognosis of various types of cancer. The potential molecular mechanisms and the interaction among long non‑coding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs require further investigation in cervical cancer. In the present study, lncRNA, miRNA, and mRNA expression profiles of 304 primary tumor tissues from patients with cervical cancer and 3 solid normal tissues from The Cancer Genome Atlas (TCGA) dataset were studied via RNA sequencing (RNA‑seq). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were performed using R package clusterProfiler to annotate the principal functions of differentially expressed (DE) mRNAs. Kaplan‑Meier analysis was also conducted to investigate the effects of DElncRNAs, DEmiRNAs, and DEmRNAs on overall survival. A total of 2,255 mRNAs, 133 miRNAs, and 150 lncRNAs that were differentially expressed were identified with a threshold of P<0.05 and |fold change (FC)|>2. Functional enrichment analysis indicated that DEmRNAs were enriched in cancer‑associated KEGG pathways. Furthermore, 255 mRNAs, 15 miRNAs, and 12 lncRNAs that were significantly associated with overall survival in cervical carcinoma were also identified. Importantly, an miRNA‑mediated competitive endogenous RNA (ceRNA) network was successfully constructed based on the expression profiles of DElncRNAs and DEmRNAs. More importantly, it was found that the lncRNA EPB41L4A‑AS1 may function as a pivotal regulator in carcinoma of the uterine cervix. Taken together, the present study has provided novel insights into investigating the potential mechanisms underlying tumorigenesis, development, and prognosis of cervical cancer, and presented new potential avenues for cancer therapeutics.

Downregulated Long Noncoding RNA DGCR5 Acts as a New Promising Biomarker for the Diagnosis and Prognosis of Ovarian Cancer

Emerging evidence have indicated that dysregulated long noncoding ribonucleic acids act as a novel diagnostic and therapeutic target in the progression of ovarian cancer. Long noncoding RNA DiGeorge syndrome critical region gene 5 has been reported to participate in some types of human cancer progresses, but its clinical roles in ovarian cancer had been rarely reported. This study aimed to explore the expression, clinicopathological features, diagnostic, and prognostic values of DiGeorge syndrome critical region gene 5 in ovarian cancer. The total levels of DiGeorge syndrome critical region gene 5 transcript variant 1 (NR_002733.2) and 2 (NR_045121.1) in patients with ovarian cancer were determined by quantitative reverse transcription polymerase chain reaction. The correlation of DiGeorge syndrome critical region gene 5 expression with clinicopathological factors was statistically analyzed by χ² test. Overall survival analysis was carried out with the Kaplan–Meier curves with the log-rank test. Univariate and multivariate Cox regression analyses were performed to identify the prognostic significance of DiGeorge syndrome critical region gene 5 expression. Receiver operating characteristic curves were constructed to estimate the diagnostic and prognostic usefulness of DiGeorge syndrome critical region gene 5 in ovarian cancer. Results showed that relative DiGeorge syndrome critical region gene 5 expression was reduced by 36.81% and 65.79% in ovarian cancer tissues of patients and Gene Expression Omnibus DataSets (GSE119056) in contrast to normal tissues, respectively. Patients with lymph node metastasis and distant metastasis exhibited lower levels of DiGeorge syndrome critical region gene 5 in contrast to those patients with non-lymph node metastasis and non-distant metastasis, respectively. Low expression of DiGeorge syndrome critical region gene 5 was significantly associated with large tumor size, more lymph node metastasis, present distant metastasis, advanced clinical stage, and short overall survival in patients with ovarian cancer. Low expression of DiGeorge syndrome critical region gene 5 was an independent unfavorable prognostic factor for overall survival in patients with ovarian cancer. Receiver operating characteristics curves for prognosis yielded significant area under curves for lymph node metastasis, clinical stage, and overall survival. In conclusion, our study demonstrated that downregulated DiGeorge syndrome critical region gene 5 may be a new promising biomarker for predicting clinical progression and prognosis in patients with ovarian cancer.