Upregulated LINC00565 Accelerates Ovarian Cancer Progression By Targeting GAS6

Long non-coding RNA LINC00565 regulates ADAM19 expression through sponging microRNA-532-3p, thereby facilitating clear cell renal cell carcinoma progression

Proven by publications, long non-coding RNAs (lncRNAs) play critical roles in the development of clear cell renal cell carcinoma (ccRCC). Although lncRNA LINC00565 has been implicated in the progression of various cancers, its biological effects on ccRCC remain unknown. This study aimed to investigate the biological functions of LINC00565, as well as its potential mechanism in ccRCC. Here, the expression data of mature microRNAs (miRNAs) (normal: 71, tumor: 545), messenger RNAs (mRNAs), and lncRNAs (normal: 72, tumor: 539) of ccRCC were acquired from The Cancer Genome Atlas (TCGA) database and subjected to differential expression analysis. Quantitative reverse transcriptase polymerase chain reaction analyzed the expression levels of LINC00565, miR-532-3p, and ADAM19 mRNA. TCGA database, dual-luciferase report detection, and Argonaute 2 RNA immunoprecipitation were utilized to confirm the relationships between LINC00565 and miR-532-3p and between miR-532-3p and ADAM19, respectively. The progression of ccRCC cells was determined via CCK-8, colony formation, scratch healing, and transwell assays. Western blot was applied to detect the protein levels of epithelial-mesenchymal transition markers and ADAM19. We herein suggested that LINC00565 was prominently upregulated in ccRCC tissues and cells. Knockdown of LINC00565 repressed cell progression. We further predicted and validated miR-532-3p as a target of LINC00565, and miR-532-3p could target ADAM19. Knockdown of LINC00565 resulted in ADAM19 level downregulation in ccRCC cells and suppressed miR-532-3p could restore ADAM19 level. Thus, the three RNAs constructed a ceRNA network. Overexpressed ADAM19 could eliminate the anticancer effects caused by knocking down LINC00565 on ccRCC cells. In conclusion, LINC00565 upregulated ADAM19 via absorbing miR-532-3p, thereby facilitating the progression of ccRCC cells.

Identification of lncRNAs Deregulated in Epithelial Ovarian Cancer Based on a Gene Expression Profiling Meta-Analysis

Epithelial ovarian cancer (EOC) is one of the deadliest gynecological cancers worldwide, mainly because of its initially asymptomatic nature and consequently late diagnosis. Long non-coding RNAs (lncRNA) are non-coding transcripts of more than 200 nucleotides, whose deregulation is involved in pathologies such as EOC, and are therefore envisaged as future biomarkers. We present a meta-analysis of available gene expression profiling (microarray and RNA sequencing) studies from EOC patients to identify lncRNA genes with diagnostic and prognostic value. In this meta-analysis, we include 46 independent cohorts, along with available expression profiling data from EOC cell lines. Differential expression analyses were conducted to identify those lncRNAs that are deregulated in (i) EOC versus healthy ovary tissue, (ii) unfavorable versus more favorable prognosis, (iii) metastatic versus primary tumors, (iv) chemoresistant versus chemosensitive EOC, and (v) correlation to specific histological subtypes of EOC. From the results of this meta-analysis, we established a panel of lncRNAs that are highly correlated with EOC. The panel includes several lncRNAs that are already known and even functionally characterized in EOC, but also lncRNAs that have not been previously correlated with this cancer, and which are discussed in relation to their putative role in EOC and their potential use as clinically relevant tools.

Prognostic utility of lncRNAs (LINC00565 and LINC00641) as molecular markers in glioblastoma multiforme (GBM)

Background and aim

Glioblastoma multiforme (GBM) is primary brain tumor grade IV characterized by fast cell proliferation, high mortality and morbidity and most lethal gliomas. Molecular approaches underlying its pathogenesis and progression with diagnostic and prognostic value have been an area of interest. Long-non coding RNAs (lncRNAs) aberrantly expressed in GBM have been recently studied. The aim is to investigate the clinical role of lncRNA565 and lncRNA641 in GBM patients.

Patients and methods

Blood samples were withdrawn from 35 newly diagnosed GBM cases with 15 healthy individuals, then lncRNA565 and lncRNA641 expression were evaluated using real time-PCR. Their diagnostic efficacy was detected using receiver operating characteristic curve. Progression free survival (PFS) and overall survival (OS) were studied using Kaplan–Meier curves.

Results

lncRNAs expressions were increased significantly among GBM as compared to control group. Their expressions were correlated with clinico-pathological data and survival pattern for the studied GBM patients. Higher levels of both lncRNAs were correlated to worse performance status. Expression of lncRNA565 was increased with large tumor size (≥ 5 cm). Survival analysis showed that both investigated lncRNA were increased with worse PFS and OS.

Conclusion

Expression of lncRNA565 and lncRNA641 in a liquid biopsy sample can be used as prognostic biomarker for GBM patients.

Long Noncoding RNA Mediated Regulation in Human Embryogenesis, Pluripotency, and Reproduction

Long noncoding RNAs (lncRNAs), a class of noncoding RNAs with more than 200 bp in length, are produced by pervasive transcription in mammalian genomes and regulate gene expression through various action mechanisms. Accumulating data indicate that lncRNAs mediate essential biological functions in human development, including early embryogenesis, induction of pluripotency, and germ cell development. Comprehensive analysis of sequencing data highlights that lncRNAs are expressed in a stage-specific and human/primate-specific pattern during early human development. They contribute to cell fate determination through interacting with almost all classes of cellular biomolecules, including proteins, DNA, mRNAs, and microRNAs. Furthermore, the expression of a few of lncRNAs is highly associated with the pathogenesis and progression of many reproductive diseases, suggesting that they could serve as candidate biomarkers for diagnosis or novel targets for treatment. Here, we review research on lncRNAs and their roles in embryogenesis, pluripotency, and reproduction. We aim to identify the underlying molecular mechanisms essential for human development and provide novel insight into the causes and treatments of human reproductive diseases.

Identifying and characterizing lincRNA genomic clusters reveals its cooperative functions in human cancer

Background

Emerging evidence has revealed that some long intergenic non-coding RNAs (lincRNAs) are likely to form clusters on the same chromosome, and lincRNA genomic clusters might play critical roles in the pathophysiological mechanism. However, the comprehensive investigation of lincRNA clustering is rarely studied, particularly the characterization of their functional significance across different cancer types.

Methods

In this study, we firstly constructed a computational method basing a sliding window approach for systematically identifying lincRNA genomic clusters. We then dissected these lincRNA genomic clusters to identify common characteristics in cooperative expression, conservation among divergent species, targeted miRNAs, and CNV frequency. Next, we performed comprehensive analyses in differentially-expressed patterns and overall survival outcomes for patients from The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) across multiple cancer types. Finally, we explored the underlying mechanisms of lincRNA genomic clusters by functional enrichment analysis, pathway analysis, and drug-target interaction.

Results

We identified lincRNA genomic clusters according to the algorithm. Clustering lincRNAs tended to be co-expressed, highly conserved, targeted by more miRNAs, and with similar deletion and duplication frequency, suggesting that lincRNA genomic clusters may exert their effects by acting in combination. We further systematically explored conserved and cancer-specific lincRNA genomic clusters, indicating they were involved in some important mechanisms of disease occurrence through diverse approaches. Furthermore, lincRNA genomic clusters can serve as biomarkers with potential clinical significance and involve in specific pathological processes in the development of cancer. Moreover, a lincRNA genomic cluster named Cluster127 in DLK1-DIO3 imprinted locus was discovered, which contained MEG3, MEG8, MEG9, MIR381HG, LINC02285, AL132709.5, and AL132709.1. Further analysis indicated that Cluster127 may have the potential for predicting prognosis in cancer and could play their roles by participating in the regulation of PI3K-AKT signaling pathway.

Conclusions

Clarification of the lincRNA genomic clusters specific roles in human cancers could be beneficial for understanding the molecular pathogenesis of different cancer types.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-021-03179-5.

lncRNA SNHG15 Promotes Ovarian Cancer Progression through Regulated CDK6 via Sponging miR-370-3p

Ovarian cancer is a kind of cancer from the female genital tract; the molecular mechanism still needs to be explored. lncRNA plays a vital role in tumorigenesis and development. Our aim was to identify oncogenic lncRNAs in ovarian cancer and explore the potential molecular mechanism. SNHG15 was initially identified by using GEO datasets (GSE135886 and GSE119054) and validated by tumor tissues and the cell line, identifying that SNHG15 was upregulated in ovarian cancer. Besides, high SNHG15 indicated poor prognosis in ovarian cancer. Furthermore, knockdown SNHG15 suppresses ovarian cancer proliferation and promotes apoptosis. Mechanistically, SNHG15 promotes proliferation through upregulated CDK6 via sponging miR-370-3p. Taken together, our findings emphasize the important role of SNHG15 in ovarian cancer, suggesting that SNHG15 may be a promising target for ovarian cancer.

(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.

ALKBH5-HOXA10 loop-mediated JAK2 m6A demethylation and cisplatin resistance in epithelial ovarian cancer

Background

Chemotherapy resistance remains a barrier to improving the prognosis of epithelial ovarian cancer (EOC). ALKBH5 has recently been shown to be one of the RNA N6-methyladenosine (m6A) demethyltransferases associated with various cancers, but its role in cancer therapeutic resistance remains unclear. This study aimed to investigate the role of AlkB homolog 5 (ALKBH5) in cisplatin-resistant EOC.

Methods

Functional assays were performed both in vitro and in vivo. RNA sequencing (RNA-seq), m6A-modified RNA immunoprecipitation sequencing (MeRIP-seq), chromatin immunoprecipitation, RNA immunoprecipitation, and luciferase reporter and actinomycin-D assays were performed to investigate RNA/RNA interaction and m6A modification of the ALKBH5-HOXA10 loop.

Results

ALKBH5 was upregulated in cisplatin-resistant EOC and promoted cancer cell cisplatin resistance both in vivo and in vitro. Notably, HOXA10 formed a loop with ALKBH5 and was found to be the upstream transcription factor of ALKBH5. HOXA10 overexpression also facilitated EOC cell chemoresistance both in vivo and in vitro. Collective results of MeRIP-seq and RNA-seq showed that JAK2 is the m6A-modified gene targeted by ALKBH5. The JAK2/STAT3 signaling pathway was activated by overexpression of the ALKBH5-HOXA10 loop, resulting in EOC chemoresistance. Cell sensitivity to cisplatin was rescued by ALKBH5 and HOXA10 knockdown or inhibition of the JAK2/STAT3 signaling pathway in EOC cells overexpressing ALKBH5-HOXA10.

Conclusions

The ALKBH5-HOXA10 loop jointly activates the JAK2/STAT3 signaling pathway by mediating JAK2 m6A demethylation, promoting EOC resistance to cisplatin. Thus, inhibition of the expression of the ALKBH5-HOXA10 loop may be a potential strategy to overcome cisplatin resistance in EOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02088-1.

Mechanism of Circular RNA RAD23B for Regulating Glycolysis and Proliferation of Ovarian Cancer Cells by Targeting MicroRNA-519b-3p

We investigated whether circRAD23B regulates glycolysis and proliferation of ovarian cancer cells by targeting miRNA-519b-3p. circRAD23B expression in ovarian cancer tissues was significantly higher than that in paracancerous tissues, and miRNA-519b-3p expression in ovarian cance tissues was significantly lower than that in paracancerous tissues (P < 0.05). Transfection sicircRAD23B or miRNA-519b-3p mimics can greatly attenuate cell viability, glucose consumption, lactic acid level, and CyclinD1 protein level (P < 0.05), and increase p21 protein level (P < 0.05). Double luciferase reporter experiment confirmed that circRAD23B could function as a miRNA-519b-3p sponge molecule. Co-transfection of si-circRAD23B and anti-miRNA-519b-3p could greatly decrease cell viability, glucose consumption, lactic acid level, and CyclinD1 protein level (P < 0.05), and increase p21 protein level by comparison with si-circRAD23B+anti-miRNA-NC group (P < 0.05). Inhibiting circRAD23B expression can, in turn, inhibit glycolysis and the proliferation of ovarian cancer cells by up-regulating miRNA-519b-3p expression.

LncRNA FGD5-AS1 promotes the malignant phenotypes of ovarian cancer cells via targeting miR-142-5p

Long non-coding RNAs (lncRNAs) have been reported to participate in regulating gene expression and are related to tumor progression. FGD5 antisense RNA 1 (FGD5-AS1) facilitates the progression of various tumors. However, the expression and function of FGD5-AS1 in ovarian cancer (OC) and its mechanism of action are not yet clear. Real-time polymerase chain reaction (RT-PCR) was employed to explore the expression levels of FGD5-AS1 and miR-142-5p in OC. The relationship between the expression of FGD5-AS1 and clinicopathological indicators of OC patients was analyzed by χ² test. CCK-8 assay, BrdU assay, and Transwell assay were carried out to detect cell proliferation, migration, as well as invasion, respectively. Subcutaneous tumorigenesis experiment and lung metastasis model were used to examine the biological effects of FGD5-AS1 in OC in vivo. Dual luciferase reporter gene assay or RIP experiment was employed to explore the targeting relationship between FGD5-AS1 and miR-142-5p, as well as miR-142-5p and PD-L1 3'UTR. First, we found that FGD5-AS1 was markedly up-regulated in OC. Moreover, its high expression level was associated with positive local lymph node metastasis and higher T stage in OC patients. Gain-of-function and loss-of-function assays demonstrated that FGD5-AS1 facilitated the proliferation, migration, as well as invasion of OC cells. Mechanistically, it was revealed that FGD5-AS1 targeted miR-142-5p to repress its expression and function. Furthermore, miR-142-5p has a binding site for 3' UTR of PD-L1, and FGD5-AS1 could positively regulate PD-L1 expression via repressing miR-142-5p. The present study reports that FGD5-AS1/miR-142-5p/PD-L1 axis is involved in regulating OC progression.

Non-Coding RNAs as Biomarkers of Tumor Progression and Metastatic Spread in Epithelial Ovarian Cancer

Simple Summary

Despite advances in cancer research in recent years, efficient predictive biomarkers of tumor progression and metastatic spread for ovarian cancer are still missing. Therefore, we critically address recent findings in the field of non-coding RNAs (microRNAs and long non-coding RNAs) and DNA methylation in ovarian cancer patients as promising novel biomarkers of ovarian cancer progression.

Abstract

Ovarian cancer is one of the most common causes of death among gynecological malignancies. Molecular changes occurring in the primary tumor lead to metastatic spread into the peritoneum and the formation of distant metastases. Identification of these changes helps to reveal the nature of metastases development and decipher early biomarkers of prognosis and disease progression. Comparing differences in gene expression profiles between primary tumors and metastases, together with disclosing their epigenetic regulation, provides interesting associations with progression and metastasizing. Regulatory elements from the non-coding RNA families such as microRNAs and long non-coding RNAs seem to participate in these processes and represent potential molecular biomarkers of patient prognosis. Progress in therapy individualization and its proper targeting also rely upon a better understanding of interactions among the above-listed factors. This review aims to summarize currently available findings of microRNAs and long non-coding RNAs linked with tumor progression and metastatic process in ovarian cancer. These biomolecules provide promising tools for monitoring the patient’s response to treatment, and further they serve as potential therapeutic targets of this deadly disease.

Gynecologic cancers and non-coding RNAs: Epigenetic regulators with emerging roles

Gynecologic cancers involve the female genital organs, such as the vulva, vagina, cervix, endometrium, ovaries, and fallopian tubes. The occurrence and frequency of gynecologic cancer depends on personal lifestyle, history of exposure to viruses or carcinogens, genetics, body shape, and geographical habitat. For a long time, research into the molecular biology of cancer was broadly restricted to protein-coding genes. Recently it has been realized that non-coding RNAs (ncRNA), including long noncoding RNAs (LncRNAs), microRNAs, circular RNAs and piRNAs (PIWI-interacting RNAs), can all play a role in the regulation of cellular function within gynecological cancer. It is now known that ncRNAs are able to play dual roles, i.e. can exert both oncogenic or tumor suppressive functions in gynecological cancer. Moreover, several clinical trials are underway looking at the biomarker and therapeutic roles of ncRNAs. These efforts may provide a new horizon for the diagnosis and treatment of gynecological cancer. Herein, we summarize some of the ncRNAs that have been shown to be important in gynecological cancers.

LINC00565 promotes the progression of colorectal cancer by upregulating EZH2

The present study aimed to illustrate the role of LINC00565 in aggravating colorectal cancer (CRC) by targeting enhancer of zeste homolog 2 (EZH2). The relative levels of LINC00565 and EZH2 in CRC tissues, based on their Tumor-Node-Metastasis stage and tumor size, were detected by reverse transcription-quantitative polymerase chain reaction. The diagnostic value of LINC00565 in CRC was assessed by depicting receiver operating characteristic curves. Pearson's correlation test was applied to analyze the expression correlation between LINC00565 and EZH2 in CRC tissues. The transfection efficacy of three LINC00565 small interfering RNAs was examined in CRC HCT116 and SW480 cell lines. After knockdown of LINC00565, the proliferative and migratory abilities of CRC cells were detected by Cell Counting Kit-8 and Transwell assays, respectively. The subcellular distribution of LINC00565 was analyzed, and the interaction between LINC00565 and EZH2 was determined by RNA immunoprecipitation. Finally, co-regulation of LINC00565 and EZH2 on CRC cell functions was explored by performing rescue experiments. Results showed that LINC00565 was upregulated in CRC tissues, especially in patients with stage III+IV and in those with large tumor sizes, suggesting its diagnostic value in CRC. EZH2 was also upregulated in CRC tissues, showing a positive correlation with LINC00565. LINC00565 was mainly expressed in the cytoplasm and was found to bind with EZH2. Validation was performed by overexpressing EZH2, which abolished the role of silenced LINC00565 in regulating proliferative and migratory abilities in CRC. Therefore, the upregulation of LINC00565 in CRC tissues was found to stimulate the aggravation of CRC by upregulating EZH2.

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.

LINC00565 Enhances Proliferative Ability in Endometrial Carcinoma by Downregulating KLF9

Objective

To detect LINC00565 expression level in endometrial carcinoma (EC) samples and cell lines, and the correlations between LINC00565 and clinical features of EC patients. After intervening LINC00565, the underlying mechanism about proliferative ability in EC cell lines is observed.

Methods

Relative levels of LINC00565 and KLF9 in 52 paired EC and paracancerous tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between relative level of LINC00565 or KLF9 and clinical features of EC patients was analyzed. After knockdown of LINC00565 and KLF9, potential regulations of them on biological functions of EC were examined by Cell Counting Kit (CCK-8), colony formation assay and in vivo xenograft model in nude mice, respectively. At last, dual-luciferase reporter assay and rescue experiments were conducted to illustrate the mechanisms of LINC00565 and KLF9 in mediating the development of EC.

Results

LINC00565 was upregulated in EC tissues. Chi-square analysis showed that a high level of LINC00565 predicted large tumor size, advanced pathological staging and poor prognosis in EC. Silence of LINC00565 decreased proliferative ability in EC cells and tumor growth in nude mice bearing EC. KLF9 was the target gene of LINC00565. The negative interaction between LINC00565 and KLF9 was responsible for stimulating the malignant development of EC. Knockdown of KLF9 could abolish the regulatory effects of silenced LINC00565 on proliferative ability and tumorigenesis in EC.

Conclusion

LINC00565 is upregulated in EC tissues and closely linked to tumor size, pathological staging and poor prognosis in EC patients. LINC00565 stimulates proliferative ability in EC by downregulating KLF9.

The Challenges and Opportunities of LncRNAs in Ovarian Cancer Research and Clinical Use

Ovarian cancer is one of the most lethal gynecological malignancies worldwide because it tends to be detected late, when the disease has already spread, and prognosis is poor. In this review we aim to highlight the importance of long non-coding RNAs (lncRNAs) in diagnosis, prognosis and treatment choice, to make progress towards increasingly personalized medicine in this malignancy. We review the effects of lncRNAs associated with ovarian cancer in the context of cancer hallmarks. We also discuss the molecular mechanisms by which lncRNAs become involved in cellular physiology; the onset, development and progression of ovarian cancer; and lncRNAs' regulatory mechanisms at the transcriptional, post-transcriptional and post-translational stages of gene expression. Finally, we compile a series of online resources useful for the study of lncRNAs, especially in the context of ovarian cancer. Future work required in the field is also discussed along with some concluding remarks.