A novel lncRNA, Lnc-OC1, promotes ovarian cancer cell proliferation and migration by sponging miR-34a and miR-34c

Hederagenin suppresses ovarian cancer via targeting mitochondrial fission through dynamin-related protein 1

A triterpenoid isolated from the plant Hedera helix, hederagenin was discovered to have anti-cancer, anti-inflammatory, anti-depressant and anti-fibrosis properties both in vivo and in vitro. In this study, the relationship between mitochondrial fission and hederagenin-induced apoptosis in ovarian cancer (OC) was investigated and the underlying mechanisms were deciphered. Hederagenin's cytotoxicity on OC cells was analyzed using colony formation and CCK-8 assays. The effect of hederagenin on OC cells was also verified by a mouse xenograft tumor model. Flow cytometric analysis was conducted to examine hederagenin's effects on mitochondrial membrane potential, apoptosis, and cell cycle OC cells. MitoTracker Red (CMXRos) staining was performed to observe the mitochondrial morphology. The protein levels of Bak, Bcl-2, Caspase 3, Caspase 9, Cyclin D1 and Bax were measured by Western blot. This study found that hederagenin could suppress the in vivo and in vitro SKOV3 and A2780 cell proliferation in an effective manner. Besides, hederagenin altered the mitochondrial membrane potential, induced S-phase and G0/G1-phase arrest, mitochondrial morphology changes, and apoptosis in OC cells. Additionally, our findings further demonstrated that hederagenin changed the mitochondrial morphology by suppressing dynamin-related protein 1 (Drp1), a crucial mitochondrial division factor. Moreover, Drp1 overexpression could reverse hederagenin-induced apoptosis, whereas the Drp1 knockdown had the opposite effect. Furthermore, hederagenin may trigger BAX mitochondrial translocation and apoptosis in OC cells. These results provided a novel perspective on the relationship between the modulation of mitochondrial morphology and the suppression of ovarian cancer by hederagenin.

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.

EMT/MET plasticity in cancer and Go-or-Grow decisions in quiescence: the two sides of the same coin?

Epithelial mesenchymal transition (EMT) and mesenchymal epithelial transition (MET) are genetic determinants of cellular plasticity. These programs operate in physiological (embryonic development, wound healing) and pathological (organ fibrosis, cancer) conditions. In cancer, EMT and MET interfere with various signalling pathways at different levels. This results in gross alterations in the gene expression programs, which affect most, if not all hallmarks of cancer, such as response to proliferative and death-inducing signals, tumorigenicity, and cell stemness. EMT in cancer cells involves large scale reorganisation of the cytoskeleton, loss of epithelial integrity, and gain of mesenchymal traits, such as mesenchymal type of cell migration. In this regard, EMT/MET plasticity is highly relevant to the Go-or-Grow concept, which postulates the dichotomous relationship between cell motility and proliferation. The Go-or-Grow decisions are critically important in the processes in which EMT/MET plasticity takes the central stage, mobilisation of stem cells during wound healing, cancer relapse, and metastasis. Here we outline the maintenance of quiescence in stem cell and metastatic niches, focusing on the implication of EMT/MET regulatory networks in Go-or-Grow switches. In particular, we discuss the analogy between cells residing in hybrid quasi-mesenchymal states and G_Alert, an intermediate phase allowing quiescent stem cells to enter the cell cycle rapidly.

LncRNA LNCOC1 is Upregulated in Melanoma and Serves as a Potential Regulatory Target of miR-124 to Suppress Cancer Cell Invasion and Migration

Background

A cascade of genes and pathways have been reported in the precise regulation of malignant melanoma (MM). Previous study has demonstrated that lncRNA LNCOC1 is an oncogenic factor in the pathogenesis and development of various cancers. The present study explored the functionalities of LNCOC1 and its interactions with miR-124 in MM.

Methods

A total of 65 melanoma patients were enrolled in this study. The expression of LNCOC1 and miR-124 after cell transfection were detected by RT-qPCR. The migration rates of SK-MEL-3 and A375 cells after transient transfection with LNCOC1 expression vector and miR-124 mimic was detected by trans-well assay.

Results

LNCOC1 was accumulated to high levels in melanoma, and it was significantly correlated with the low survival rate of melanoma patients. Our bioinformatics data showed that miR-124 could target LNCOC1. Overexpression of miR-124 could downregulate LNCOC1. However, up-regulated the expression of LNCOC1 did not affect the expression of miR-124. Our correlation analysis also revealed that the expression of LNCOC1 and miR-124 were inversely correlated in both melanoma tissues and non-tumor tissues. The trans-well invasion and migration assays indicated that overexpression of miR-124 inhibited the melanoma cell invasion and migration. However, overexpression of LNCOC1 promoted melanoma cell invasion and migration.

Conclusion

LNCOC1 is upregulated in melanoma, which can be considered as a potential target of miR-124 in modulating melanoma cell invasion and migration. LNCOC1 may also be an interfering target of MM therapy.

LncRNA Neu Mediates Bone Marrow Mesenchymal Stem Cells (BMSCs) Growth and Promotes Cervical Cancer Progression Through Suppression of MicroRNA-625

The tumorigenesis mechanism of cervical cancer (CC) is complicated as several pathways deserve exploration. LncRNAs are recently highlighted to be involved in various biological processes. The role of bone marrow mesenchymal stem cells (BMSCs) in tumor regulation is recently investigated. Herein, we aimed to explore the interaction between lncRNA Neu and microRNA (miR)-625 and BMSCs in CC. Expression levels of lncRNA Neu and miR-625 in CC cells and BMSCs were determined by RT-qPCR. The relationship between lncRNA Neu and miR-625 was analyzed by Pearson correlation analysis. After cancer cells were transfected with siRNA-Neu, CCK-8 assay and clone formation assay were conducted to determine cell proliferation and viability. LncRNA Neu was highly expressed in CC cells and poorly expressed in BMSCs. Knockdown of lncRNA Neu attenuated cell viability and proliferation while increased miR-625 expression. MiR-625 expression was negatively correlated with expression of lncRNA Neu in CC cells. Overexpression of miR-625 resulted in weakened CC cell viability. Collectively, lncRNA Neu was highly expressed in CC and promoted the development of CC through stimulating the growth of BMSCs and suppressing miR-625 expression. These findings provide a novel insight into targeted therapy for CC.

MicroRNA-323a-3p Negatively Regulates NEK6 in Colon Adenocarcinoma Cells

Objective. The activity of NEK6 is enhanced in several cancer cells, including colon adenocarcinoma (COAD) cells. However, there are few reports on the microRNA (miRNA/miR) regulation of NEK6. In this study, we aimed to investigate the effects of miRNAs targeting NEK6 in COAD cells. Methods. Public data and online analysis sites were used to analyze the expression levels of NEK6 and miR-323a-3p in COAD tissues as well as the relationship between NEK6 or miR-323a-3p levels and survival in patients with COAD and to predict miRNAs targeting NEK6. Real-time polymerase chain reaction and western blotting were performed to determine the levels of NEK6 and miR-323a-3p in COAD cells. The targeting of NEK6 by miR-323a-3p was verified using a dual-luciferase reporter assay. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, 5-ethynyl-2′-deoxyuridine assay, propidium iodide (PI) staining, annexin V-fluorescein isothiocyanate/PI staining, and transwell assay were employed to test the proliferation, apoptosis, migration ability, and invasiveness of COAD cells. Results. In COAD cells, NEK6 was highly expressed, whereas miR-323a-3p was expressed at low levels and negatively regulated NEK6. Upregulating the level of miR-323a-3p impaired the proliferation, migration, and invasion of COAD cells and promoted apoptosis, whereas supplementing NEK6 alleviated the damage of the proliferation, migration, and invasion of COAD cells caused by miR-323a-3p and inhibited miR-323a-3p-induced apoptosis. These findings indicate that miR-323a-3p regulates the proliferation, migration, invasion, and apoptosis of COAD cells by targeting NEK6. Conclusion. miR-323a-3p downregulates NEK6 in COAD cells; this provides a novel basis for further understanding the occurrence and development of COAD.

ceRNAs in Cancer: Mechanism and Functions in a Comprehensive Regulatory Network

Noncoding RNAs have been shown with powerful ability in post-transcriptional regulation, enabling intertwined RNA crosstalk and global molecular interaction in a large amount of dysfunctional conditions including cancer. Competing endogenous RNAs (ceRNAs) are those competitively binding with shared microRNAs (miRNAs), freeing their counterparts from miRNA-induced degradation, thus actively influencing and connecting with each other. Constantly updated analytical approaches boost outstanding advancement achieved in this burgeoning hotspot in multilayered intracellular communication, providing new insights into pathogenesis and clinical treatment. Here, we summarize the mechanisms and correlated factors under this RNA interplay and deregulated transcription profile in neoplasm and tumor progression, underscoring the great significance of ceRNAs for diagnostic values, monitoring biomarkers, and prognosis evaluation in cancer.

Identification of Differentially Expressed Circular RNAs as miRNA Sponges in Lung Adenocarcinoma

Background

Circular RNAs (circRNAs) may function as the decoys for microRNAs (miRNAs) or proteins, the templates for translation, and the sources of pseudogene generation. The purpose of this study is to determine the diagnostic circRNAs, which are related to lung adenocarcinoma (LUAD), that adsorb miRNAs on the basis of the competing endogenous RNA (ceRNA) hypothesis.

Methods

The differentially expressed circRNAs (DEcircRNAs) in LUAD were revealed by the microarray data (GSE101586 and GSE101684) that were obtained from the Gene Expression Omnibus (GEO) database. The miRNAs that were targeted by the DEcircRNAs were predicted with the CircInteractome, and the target mRNAs of the miRNAs were found by the miRDB and the TargetScan. The ceRNA network was built by the Cytoscape. The potential biological roles and the regulatory mechanisms of the circRNAs were investigated by the Gene Ontology (GO) enrichment analysis and the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. The expression of the host genes of circRNAs was examined by the Ualcan. The survival analysis was performed by the Kaplan-Meier plotter.

Results

In comparison with normal lung tissues, LUAD tissues contained 7 overlapping cancer-specific DEcircRNAs with 294 miRNA response elements (MREs). Among the 7 DEcircRNAs, 3 circRNAs (hsa_circ_0072088, hsa_circ_0003528, and hsa_circ_0008274) were upregulated and 4 circRNAs (hsa_circ_0003162, hsa_circ_0029426, hsa_circ_0049271, and hsa_circ_0043256) were downregulated. A circRNA-miRNA-mRNA regulatory network, which included 33 differentially expressed miRNAs (DEmiRNAs) and 2007 differentially expressed mRNAs (DEmRNAs), was constructed. These mRNAs were enriched in the biological function of cell-cell adhesion, response to hypoxia, and stem cell differentiation and were involved in the PI3K-Akt signaling, HIF-1 signaling, and cAMP signaling pathways.

Conclusion

Our results indicated that 7 DEcircRNAs could have diagnostic value for LUAD. Additionally, the circRNAs-mediated ceRNA network might provide a novel perspective into unraveling the pathogenesis and progression of LUAD.

Long non-coding RNA PCED1B antisense RNA 1 promotes gastric cancer progression via modulating microRNA-215-3p / C-X-C motif chemokine receptor 1 axis

Long non-coding RNAs (lncRNAs) emerge as vital modulators and tissue-specific biomarkers of multiple cancers, including gastric cancer (GC). Instead, the expression characteristics, biological function and molecular mechanism of lncRNA PCED1B antisense RNA 1 (PCED1B-AS1) in GC await more elaboration. In this study, 48 cases of GC tissues and matched non-cancerous tissues were collected, and PCED1B-AS1, microRNA-215-3p (miR-215-3p) and C-X-C motif chemokine receptor 1 (CXCR1) expression levels were detected by qRT-PCR. Besides, CCK-8, EdU, Transwell and Western blot assays were conducted to assess the impact of PCED1B-AS1 or miR-215-3p on cell growth, migration, invasion and epithelial-mesenchymal transition (EMT). The interaction between genes was verified by bioinformatics analysis, rna immunoprecitipation (RIP) and dual-luciferase reporter gene assays. We demonstrated that, PCED1B-AS1 expression level was raised in GC tissues and cell lines, and increased expression of PCED1B-AS1 was in association with tumor size, TNM stage and lymph node metastasis in GC patients. Additionally, PCED1B-AS1 overexpression promoted GC cells proliferation, migration, invasion and EMT, and miR-215-3p overexpression counteracted the biological effects of PCED1B-AS1. Mechanistically, PCED1B-AS1 specifically inhibited miR-215-3p expressions, thus up-regulating CXCR1 expressions. In conclusion, PCED1B-AS1 accelerates GC progression via adsorbing miR-215-3p and up-regulating CXCR1, indicating that PCED1B-AS1 is a novel therapeutic target for treating GC.

RHPN1‑AS1 promotes ovarian carcinogenesis by sponging miR‑6884‑5p thus releasing TOP2A mRNA

Ovarian cancer, a severe lethal gynecological malignancy, is characterized by both high morbidity and mortality. Long noncoding RNAs (lncRNAs) have recently caused extensive concern due to their regulatory function in various human tumors. There are a mounting number of lncRNAs that are in extreme need of research, serving as biomarkers for diagnosis and therapy for ovarian cancer. In the present study, RT-qPCR was employed to detect how Rhophilin Rho GTPase binding protein 1 antisense RNA1 (RHPN1-AS1), miR-6884-5p and DNA topoisomerase IIα (TOP2A) are expressed in ovarian cancer tissues or cell lines. BrdU, MTT, colony formation and cell adhesion assays, caspase-3 activity, flow cytometry and wound healing assay were employed to assess cell proliferation, viability, colony number, adhesion, apoptosis and migration in ovarian cancer, respectively. RHPN1-AS1 was determined to be enriched in ovarian cancer tissues and cell lines. Silencing of RHPN1-AS1 was reported to increase cell apoptosis and impair cell proliferation, viability, colony number, adhesion and migration in vitro. Furthermore, RHPN1-AS1 was able to sponge miR-6884-5p which directly targets TOP2A in ovarian cancer. Notably, silencing of RHPN1-AS1 functionally reversed the oncogenic effect induced by the miR-6884-5p inhibitor, while the miR-6884-5p inhibitor markedly restored the inhibition of ovarian carcinogenesis modulated by silencing TOP2A in ovarian cancer. RHPN1-AS1 was found to promote ovarian carcinogenesis via sponging miR-6884-5p thus releasing TOP2A, and RHPN1-AS1 may act as a promising biomarker for the prognosis and therapy of ovarian cancer.

SMILR Aggravates the Progression of Atherosclerosis by Sponging miR-10b-3p to Regulate KLF5 Expression

Over the past few decades, long noncoding RNAs (lncRNAs) have been widely accepted to be involved in various diseases, and smooth muscle enriched long noncoding RNA (SMILR) was reported to participate in the proliferation of vascular smooth muscle cells (VSMCs). Nevertheless, the molecular mechanisms of SMILR in atherosclerosis (AS) have not been fully explored. In this study, VSMCs and human mononuclear cells (U937) treated with oxidized low-density lipoprotein (ox-LDL) were used as cell models of AS. We found that the expression of SMILR was upregulated in the serum of AS patients and ox-LDL-induced AS cell models. SMILR knockdown inhibited cell proliferation while increasing cell apoptosis in the AS cell models. In addition, SMILR acted as a sponge for miR-10b-3p, and miR-10b-3p counteracted SMILR-mediated regulation of AS. Moreover, we confirmed that miR-10b-3p could bind with KLF5, and SMILR regulated KLF5 expression by competitively binding miR-10b-3p. Furthermore, miR-10b-3p modulated cell proliferation and apoptosis in AS by targeting KLF5. Finally, miR-10b-3p regulated AS progression in vivo by targeting KLF5. Overall, our study demonstrated that SMILR participated in the progression of AS by targeting the miR-10b-3p/KLF5 axis, which may provide some clues for future studies of AS.

Long non-coding RNA ZFAS1 exerts a protective role to alleviate oxygen and glucose deprivation-mediated injury in ischemic stroke cell model through targeting miR-186-5p/MCL1 axis

In recent years, accumulating articles have revealed that long non-coding RNAs (lncRNAs) play crucial roles in ischemic stroke (IS). A previous study found that lncRNA zinc finger antisense 1 (ZFAS1) was down-regulated in IS patients compared with healthy controls. However, the precise function of ZFAS1 in IS and its associated mechanism remain unclear. Cell viability was assessed by cell counting kit-8 (CCK8) assay. Cell apoptosis was analyzed by flow cytometry. Western blot assay and quantitative real-time polymerase chain reaction (qRT-PCR) were conducted to measure protein and RNA expression. The interaction between microRNA-186-5p (miR-186-5p) and ZFAS1 or MCL1 apoptosis regulator, BCL2 family member (MCL1) was confirmed by dual-luciferase reporter assay, RNA-pull down assay and RNA immunoprecipitation (RIP) assay. IS cell model was established through exposing N2a cells to oxygen and glucose deprivation (OGD). OGD exposure restrained the viability and induced the apoptosis of N2a cells. OGD exposure down-regulated the expression of ZFAS1 and up-regulated the level of miR-186-5p in a time-dependent manner. ZFAS1 overexpression alleviated OGD-mediated injury in IS cell model. MiR-186-5p was identified as a direct target of ZFAS1, and OGD-induced injury in IS cell model was attenuated by the silence of miR-186-5p. MiR-186-5p interacted with the 3' untranslated region (3'UTR) of MCL1 messenger RNA (mRNA). ZFAS1 positively regulated MCL1 mRNA expression by sequestering miR-186-5p in N2a cells. ZFAS1 overexpression-mediated protective effects in IS cell model were partly overturned by the overexpression of miR-186-5p. MCL1 silencing partly counteracted the protective effects mediated by miR-186-5p silencing in IS cell model. In conclusion, ZFAS1 overexpression exerted a protective role in IS cell model to attenuate OGD-induced injury through targeting miR-186-5p/MCL1 axis. ZFAS1/miR-186-5p/MCL1 signaling might be a novel diagnostic marker and promising treatment target for IS patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-021-00481-4.

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

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

The comprehensive landscape of miR-34a in cancer research

MicroRNA-34 (miR-34) plays central roles in human diseases, especially cancers. Inactivation of miR-34 is detected in cancer cell lines and tumor tissues versus normal controls, implying its potential tumor-suppressive effect. Clinically, miR-34 has been identified as promising prognostic indicators for various cancers. In fact, members of the miR-34 family, especially miR-34a, have been convincingly proved to affect almost the whole cancer progression process. Here, a total of 512 (miR-34a, 10/21), 85 (miR-34b, 10/16), and 114 (miR-34c, 10/14) putative targets of miR-34a/b/c are predicted by at least ten miRNA databases, respectively. These targets are further analyzed in gene ontology (GO), KEGG pathway, and the Reactome pathway dataset. The results suggest their involvement in the regulation of signal transduction, macromolecule metabolism, and protein modification. Also, the targets are implicated in critical signaling pathways, such as MAPK, Notch, Wnt, PI3K/AKT, p53, and Ras, as well as apoptosis, cell cycle, and EMT-related pathways. Moreover, the upstream regulators of miR-34a, mainly including transcription factors (TFs), lncRNAs, and DNA methylation, will be summarized. Meanwhile, the potential TF upstream of miR-34a/b/c will be predicted by PROMO, JASPAR, Animal TFDB 3.0, and GeneCard databases. Notably, miR-34a is an attractive target for certain cancers. In fact, miR-34a-based systemic delivery combined with chemotherapy or radiotherapy can more effectively control tumor progression. Collectively, this review will provide a panorama for miR-34a in cancer research.

lncRNA HEIH accelerates cell proliferation and inhibits cell senescence by targeting miR-3619-5p/CTTNBP2 axis in ovarian cancer

OBJECTIVE

Epithelial ovarian cancer is the most lethal malignancy in gynecology. Numerous studies have confirmed that long noncoding RNAs (lncRNAs) are abnormally expressed in ovarian cancer and are closely associated with the cell proliferation and senescence in cancers. However, the role and underlying molecular mechanism of long noncoding RNA high expression in hepatocellular carcinoma (HEIH) in ovarian cancer remain unknown.

METHODS

Experiments including Real-time quantitative polymerase chain reaction, RNA immunoprecipitation, luciferase reporter, Fluorescence in situ hybridization, western blot, colony formation assays, β-galactosidase senescence assay, cell apoptosis, proliferation, invasion, and migration assays were applied to investigate the role of HEIH in ovarian cancer. The data were expressed as the mean ± standard deviation. Student t test was used to compare the data between two groups. The one-way analysis of variance was applied to compare the data among multiple groups with Tukey post hoc test. All experiments were repeated three times. P < 0.05 was considered statistically significant.

RESULTS

Herein, HEIH expression was found to be up-regulated in ovarian cancer tissues (n = 25; twofold higher than normal tissues, P < 0.05) and cell lines (sixfold higher than normal ovarian epithelial cell line on average, P < 0.05), and high HEIH expression predicted poor prognosis (survival rate is about 25% after 40 mo; P < 0.05). Moreover, we found that HEIH accelerated proliferation, migration, and invasion, whereas inhibited cell senescence in ovarian cancer (P < 0.05). In mechanism, HEIH was confirmed to serve as a sponge for miR-3619-5p, and miR-3619-5p counteracted HEIH-mediated regulation of ovarian cancer (P < 0.05). Besides, cortactin-binding protein 2 (CTTNBP2) was found to be the downstream target of miR-3619-5p. Rescue assays validated that CTTNBP2 up-regulation significantly reversed the inhibitory effects of HEIH knockdown on ovarian cancer progression (P < 0.05). Furthermore, we found that HEIH facilitated tumor growth in vivo by regulating CTTNBP2 expression (P < 0.05).

CONCLUSIONS

In conclusion, our research revealed that HEIH accelerated cell proliferation, migration and invasion, whereas inhibited cell senescence in ovarian cancer via targeting the miR-3619-5p/CTTNBP2 axis. These findings may be valuable for finding new therapeutic targets to improve ovarian cancer treatment.

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.

Overview of host miRNA properties and their association with epigenetics, long non-coding RNAs, and Xeno-infectious factors

MicroRNA-derived structures play impressive roles in various biological processes. So dysregulation of miRNAs can lead to different human diseases. Recent studies have extended our comprehension of the control of miRNA function and features. Here, we overview some remarkable miRNA properties that have potential implications for the miRNA functions, including different variants of a miRNA called isomiRs, miRNA arm selection/arm switching, and the effect of these factors on miRNA target selection. Besides, we review some aspects of miRNA interactions such as the interaction between epigenetics and miRNA (different miRNAs and their related processing enzymes are epigenetically regulated by multiple DNA methylation enzymes. moreover, DNA methylation could be controlled by diverse mechanisms related to miRNAs), direct and indirect crosstalk between miRNA and lnc (Long Non-Coding) RNAs as a further approach to conduct intercellular regulation called "competing endogenous RNA" (ceRNA) that is involved in the pathogenesis of different diseases, and the interaction of miRNA activities and some Xeno-infectious (virus/bacteria/parasite) factors, which result in modulation of the pathogenesis of infections. This review provides some related studies to a better understanding of miRNA involvement mechanisms and overcoming the complexity of related diseases that may be applicable and useful to prognostic, diagnostic, therapeutic purposes and personalized medicine in the future.

Long noncoding RNA GAS5 ameliorates chronic constriction injury induced neuropathic pain in rats by modulation of the miR-452-5p/CELF2 axis

Neuropathic pain is a type of spontaneous pain that causes damage to the central nervous system. Long noncoding RNAs (lncRNAs) participate in the progression of various nervous system diseases, including neuropathic pain. However, the biological function of GAS5 in neuropathic pain remains unclear. Our findings revealed that GAS5 was downregulated in chronic constriction injury (CCI) rats. Besides, ELISA showed that the concentration of IL-6, TNF-α, and IL-1β were reduced by overexpressed GAS5 in spinal cord homogenates of CCI rats. Moreover, mechanical allodynia and thermal hyperalgesia in CCI rats were inhibited by GAS5 overexpression, suggesting that GAS5 overexpression attenuated neuropathic pain. Subsequently, we found that GAS5 served as a sponge for miR-452-5p in CCI rats and CELF2 was the downstream target of miR-452-5p. Finally, through a rescue assay, we found that GAS5 ameliorated neuropathic pain in CCI rats by sponging miR-452-5p to regulate CELF2 expression. Our study confirmed that GAS5 ameliorated neuropathic pain in rats by modulation of the miR-452-5p/CELF2 axis, which may provide some clues for neuropathic pain treatment.

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.

LncRNA BBOX1-AS1 Aggravates the Development of Ovarian Cancer by Sequestering miR-361-3p to Augment PODXL Expression

Ovarian cancer (OC) is a kind of common gynecological malignancy around the world. Mounting literatures have confirmed the implication of lncRNAs in the development of various cancers. Long non-coding RNA (LncRNA) BBOX1-AS1 has not been reported in most cancer types including OC. Presently, we aimed at exploring the function and regulatory mechanism of BBOX1-AS1 in OC. As a result, we demonstrated the extremely high BBOX1-AS1 expression in OC tissues and cells. BBOX1-AS1 silence inhibited OC progression by suppressing cell proliferation and promoting cell apoptosis. Importantly, BBOX1-AS1 was verified to bind to miR-361-3p, which presented a low expression trend in OC cells. Subsequently, PODXL was testified as the downstream target of miR-361-3p. Of note, BBOX1-AS1 positively regulated PODXL through their competition in binding with miR-361-3p. Furthermore, miR-361-3p inhibition facilitated the growth of BBOX1-AS1-deficient OC cells, while such facilitating effect was then counteracted in response to PODXL depletion. All the results above explained that BBOX1-AS1 was overexpressed in OC and that BBOX1-AS1 caused carcinogenic influences on OC cell growth via miR-361-3p/PODXL pathway, highlighting BBOX1-AS1 as a novel potential target for OC treatment.

Analysis of microRNA-34a expression profile and rs2666433 variant in colorectal cancer: a pilot study

MicroRNAs (miRNAs) are implicated in every stage of carcinogenesis and play an essential role as genetic biomarkers of cancer. We aimed to evaluate microRNA-34a gene (MIR34A) expression in colorectal cancer (CRC) tissues compared with non-cancer one and to preliminarily explore the association of one related variant to CRC risk. A total of 116 paraffin-embedded colon specimens were enrolled. MiR-34a was quantified by qPCR, and rs2666433 (A/G) genotyping was performed by TaqMan Real-Time PCR. Also, the somatic mutation burden was assessed. MIR34A expression in the CRC specimens was significantly upregulated (median = 21.50, IQR: 7.0–209.2; P = 0.001) relative to the non-cancer tissues. Allele (A) was highly prevalent in CRC tissues represented 0.56 (P < 0.001). AA/AG genotype carriers were 5.7 and 2.8 more likely to develop cancer than GG carriers. Tumor-normal tissue paired analysis revealed genotype concordance in 33 out of 58 tissue samples. Approximately 43% of the specimens showed a tendency for G to A shift. Additionally, a higher frequency of somatic mutation (92%) was observed in adenocarcinoma (P = 0.006). MIR34A expression and gene variant did not show associations with the clinicopathological data. However, G > A somatic mutation carriers had more prolonged DFS and OS. Bioinformatics analysis revealed miR-34a could target 30 genes that are implied in all steps of CRC tumorigenesis. In conclusion, this study confirms MIR34A upregulation in CRC tissues, and its rs2666433 (A/G) variant showed association with CRC and a high somatic mutation rate in cancer tissues. MiR-34a could provide a novel targeted therapy after validation in large-scale studies.

Progress of long noncoding RNAs in anti-tumor resistance

The resistance of cancer cells to anti-cancer drugs is an important reason for the failure of treatment. Overcoming drug resistance can achieve long-lasting and efficient cancer treatment. Long non-coding RNA (lncRNA) is a class of RNA molecules that does not encode protein and has more than 200 nucleotides. LncRNA not only has a regulatory role in the occurrence and development of malignant tumors, but also has been found to have a potential impact on anti-tumor resistance. Abnormal expression of lncRNA can cause tumor cells to develop resistance to anti-tumor drugs. This article reviews the recent research progress of lncRNA in various tumor resistances and the mechanism of lncRNA acting on tumor drug resistance.

Expression and diagnostic value of miR-34c and miR-141 in serum of patients with colon cancer

Expression of miR-34c and miR-141 in serum of colon cancer patients and their association with clinicopathological features and diagnostic value for colon cancer were investigated. A total of 64 patients with colon cancer admitted to Hubei Cancer Hospital from January 2016 to March 2018 were included in the experimental group, and 64 healthy subjects undergoing physical examination during the same period were the control group. The expression of miR-34c and miR-141 in serum of patients in the two groups were detected by RT-qPCR, and the association of miR-34c and miR-141 with the clinicopathological characteristics of colon cancer patients was analyzed. The receiver operating characteristic (ROC) curve was used to assess the diagnostic efficiency of miR-34c and miR-141 in colon cancer. The expression of miR-141 in serum of patients in the experimental group was significantly higher than that in the control group (P<0.05). Expression of miR-34c in serum of patients in the experimental group was significantly lower than that in the control group (P<0.05) and the expression of miR-34c and miR-141 in serum of the experimental group were associated with tumor diameter, clinical stage, degree of differentiation and lymph node metastasis (P<0.05). AUC of serum miR-34c in the diagnosis of colon cancer was 0.857 (95% CI: 0.795-0.919), with the cut-off value of 0.800, the diagnostic sensitivity of 84.38%, and the specificity of 68.75% and AUC of serum miR-141 in the diagnosis of colon cancer was 0.876 (95% CI: 0.810-0.941), with the cut-off value of 0.282, the diagnostic sensitivity of 70.31%, and the specificity of 96.88%. The ROC curve for the diagnosis of colon cancer was further plotted in combination with serum miR-34c and miR-141. AUC of the two combined for the diagnosis of colon cancer was 0.929 (95% CI: 0.884-0.974), with the cut-off value of 0.566, the diagnostic sensitivity of 84.38%, and the specificity of 93.75%. In conclusion, miR-34c and miR-141 might be involved in the occurrence and progression of colon cancer and could be used as biological indicators for early diagnosis of colon cancer.

Inhibition of Lnc-OC1 Induced Cell Apoptosis and Decreased Cell Viability by Releasing miR-34a and Inhibiting PD-L1 in Endometrial Carcinoma

Now, there is a growing awareness of the role to long non-coding RNAs (lncRNAs) in tumorigenesis and progression of a variety of malignancies including endometrial carcinoma (EC). Here, we explored the potential molecular mechanism of Lnc-OC1, a novel lncRNA, in the development of EC. Our results suggested that Lnc-OC1 was significantly upregulated in EC tissues comparing with normal tissues. Besides, Lnc-OC1 was higher expressed in the more advanced stage of EC. Therefore, Lnc-OC1 might be a crucial regulator in the progress of EC. Moreover, knockdown of Lnc-OC1 leaded to an inhibition of cell viability and a raise of cell apoptosis. In addition, Lnc-OC1 could sponge miR-34a and thus decrease its expression. miR-34a was proved to be a tumor suppressor in different malignance, hence downregulating Lnc-OC1 helped to alleviate EC by releasing miR-34a. Furthermore, rescue experiments significantly indicated that knockdown of Lnc-OC1 inhibited cell growth through repressing PD-L1 expression at least partially. Concisely, our results proved that Lnc-OC1/miR-34a/PD-L1 axis might serve as a therapeutic target of EC.

miR-34a/c induce caprine endometrial epithelial cell apoptosis by regulating circ-8073/CEP55 via the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways

microRNAs (miRNAs) and circular RNAs (circRNAs) are important for endometrial receptivity establishment and embryo implantation in mammals. miR-34a and miR-34c are highly expressed in caprine receptive endometrium (RE). Herein, the functions and mechanisms of miR-34a/c in caprine endometrial epithelial cell (CEEC) apoptosis and RE establishment were investigated. miR-34a/c downregulated the expression level of centrosomal protein 55 (CEP55) and were sponged by circRNA8073 (circ-8073), thereby exhibiting a negative interaction in CEEC. miR-34a/c induced CEEC apoptosis by targeting circ-8073/CEP55 through the regulation of the RAS/RAF/MEK/ERK and phosphoitide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways. Positive and negative feedback loops and cross-talk were documented between the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways. miR-34a/c regulated the levels of RE marker genes, including forkhead box M1, vascular endothelial growth factor, and osteopontin (OPN). These results suggest that miR-34a/c not only induce CEEC apoptosis by binding to circ-8073 and CEP55 via the RAS/RAF/MEK/ERK and PI3K/AKT/mTOR pathways, but may also regulate RE establishment in dairy goats.

LBX2-AS1 up-regulated by NFIC boosts cell proliferation, migration and invasion in gastric cancer through targeting miR-491-5p/ZNF703

BACKGROUND

The crucial role of long non-coding RNAs (lncRNAs) has been certified in human cancers. The lncRNAs with abnormal expressions could act as tumor inhibitors or oncogenes in the advancement of tumors. LBX2-AS1 was once reported to accelerate esophageal squamous cell carcinoma. Nonetheless, its function in gastric cancer (GC) remained a riddle.

METHODS

RT-qPCR was used to examine the expression of NFIC/LBX2-AS1/miR-491-5p/ZNF703 in GC cell lines. The functions of LBX2-AS1 in GC were appraised by colony formation, EdU, flow cytometry analysis, transwell and wound healing assays. Luciferase reporter, ChIP and RNA pull down assays were utilized to evaluate the interactions among genes.

RESULTS

LBX2-AS1 was up-regulated in GC cell lines. Knockdown of LBX2-AS1 repressed the proliferative, migratory, and invasive abilities of GC cells. Moreover, LBX2-AS1 was transcriptionally activated by NFIC. And LBX2-AS1 could bind with miR-491-5p. Besides, miR-491-5p depletion or ZNF703 upregulation could counteract the repressing effects of LBX2-AS1 silence on GC progression.

CONCLUSION

In a word, LBX2-AS1 up-regulated by NFIC promoted GC progression via targeting miR-491-5p/ZNF703, implying LBX2-AS1 was an underlying treatment target for GC patients.

Downregulation of Lnc-OC1 attenuates the pathogenesis of polycystic ovary syndrome

Long non-coding RNAs (lncRNAs) play a vital role in the progression of many human diseases. The aim of this study is to explore the relationship between lncRNA-ovarian cancer associated 1 (Lnc-OC1) and PCOS. In this study, we found that Lnc-OC1 was significantly higher in PCOS granulosa cells (GCs) compared to non-PCOS GCs. Lnc-OC1 knockdown inhibited cell viability and promoted cell apoptosis, expression of aromatase mRNA and production of estradiol in KGN cells. In PCOS mice, Lnc-OC1 promoted the serum insulin release, production of angiogenesis-related factors and IκBα phosphorylation, which could be partially restored by Lnc-OC1 shRNA. These results suggest that Lnc-OC1 plays an important part in the pathogenesis of PCOS.

PHD Finger Protein 19 Enhances the Resistance of Ovarian Cancer Cells to Compound Fuling Granule by Protecting Cell Growth, Invasion, Migration, and Stemness

Ovarian cancer is one of the most common gynecological malignancies in women worldwide with a poor survival rate. We have previously reported that compound fuling granule (CFG), a traditional Chinese medicinal preparation used to treat ovarian cancer in China for over 20 years, significantly promotes cell cycle arrest, apoptosis, senescence, TGFβ-induced invasion and migration, tumor growth, and distant metastasis in ovarian cancer cells. However, the underlying mechanisms are not clear. In the present study, we found that PHF19 expression in ovarian cancer cells positively correlated with their resistance ability to CFG. In addition, PHF19 overexpression increased the resistance of HEY-T30 and SKOV3 cells to CFG, while knockdown of PHF19 enhanced their sensitivity to CFG. Moreover, CFG significantly inhibited the expression of PHF19 both in mRNA and protein levels in these cells. Gain of function and loss of function experiments further proved that PHF19 is a crucial mediator involved in the ovarian cancer progression, including cell proliferation, invasion, migration, and stemness. Importantly, rescue the expression of PHF19 reverted CFG-induced suppression in ovarian cancer cell growth, EMT and stemness, while PHF19 knockdown accelerated CFG’s anti-tumor effect. Overall, our results provide a series of evidence to reveal that PHF19 is critical suppressor for CFG’s anti-tumor effect in ovarian cancer.

LncRNA ANRIL promotes cell proliferation, migration and invasion during acute myeloid leukemia pathogenesis via negatively regulating miR-34a

OBJECTIVE

LncRNA ANRIL (antisense non-coding RNA in the INK4 locus) was highly expressed in acute myeloid leukemia (AML) patients to promote AML pathogenesis. In this study, we aimed to investigate the roles and molecular events of ANRIL associated with AML progression.

METHODS

Expression patterns of ANRIL and miR-34a in the bone marrow (BM) samples and cell lines were determined using qRT-PCR. Cell proliferation, apoptosis, migration and invasion of cells with ANRIL knockdown or miR-34a overexpression were assessed by CCK-8, EdU staining, flow cytometry and Transwell assays, respectively. The dual-luciferase reporter assay was employed to validate the relationship between miR-34a and Histone deacetylase 1 (HDAC1). The binding of E2 F1 (E2 F transcription factor 1) with gene promoter was analyzed by ChIP. Furthermore, the tumorigenicity of AML was determined by xenograft transplantation in nude mice.

RESULTS

ANRIL was up-regulated both in the BM samples from AML patients and cell lines (HL-60 and THP-1), of which expression was negatively correlated with miR-34a expression. ANRIL knockdown inhibited cell proliferation, migration and invasion but promoted apoptosis of AML cells, while overexpression of miR-34a exerted opposite effects. miR-34a was verified as a downstream gene targeted by ANRIL. Moreover, HDAC1 was a direct target of miR-34a, and HDAC1 overexpression impaired the recruitment of E2 F1 to ASPP2 (apoptosis stimulating proteins of p53) gene promoter. ANRIL knockdown significantly inhibited the tumorigenesis of AML.

CONCLUSION

ANRIL promotes AML development through HDAC1-mediated epigenetic suppression of ASPP2 via negatively regulating miR-34a, which might serve as a therapeutic target for AML treatment.

Necrostatin-1 ameliorates the pathogenesis of experimental autoimmune encephalomyelitis by suppressing apoptosis and necroptosis of oligodendrocyte precursor cells

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by neuronal demyelination. MS pathogenesis occurs via multiple mechanisms, and is mediated in part by oligodendrocyte apoptosis and a robust inflammatory response. In the present study, Necrostatin-1 (Nec-1), a specific inhibitor of the receptor-interacting protein 1 kinase domain, was revealed to effectively alleviate the severity and pathological damage associated with experimental autoimmune encephalomyelitis (EAE), a commonly used mouse model of MS. In addition, treatment with Nec-1 significantly decreased the number of lesions and inflammatory cell infiltrates in spinal cord tissues, as well as the production of associated pro-inflammatory cytokines, including tumor necrosis factor α (TNFα), interferon-γ and interleukin-1β. Nec-1 also suppressed TNFα + zVAD-fmk-induced apoptosis and necroptosis in primary oligodendrocyte precursor cells. The present study revealed that Nec-1 effectively attenuated the progression of EAE by suppressing apoptosis and necroptosis in oligodendrocytes, and represents a potential novel therapeutic agent for the treatment of MS.

LncRNA PAPAS may promote triple-negative breast cancer by downregulating miR-34a

Objective

To investigate the role of promoter and pre-rRNA antisense (PAPAS) long noncoding (Lnc) RNA in cancer biology.

Methods

Tumour and tumour-adjacent healthy tissue biopsies from patients with triple-negative breast cancer (TNBC), and plasma samples from these patients plus healthy controls, were assessed for PAPAS and microRNA (miR)-34a. Effects of PAPAS and miR-34a overexpression were also investigated in vitro.

Results

PAPAS was upregulated in tumour tissues of patients with TNBC versus tumour-adjacent healthy tissues. Plasma PAPAS levels were also upregulated in patients with TNBC versus healthy controls. Levels of PAPAS in tumour tissue was significantly positively correlated with PAPAS levels in plasma from patients with TNBC. MiR-34a was downregulated in tumour tissues versus adjacent healthy tissues, and was significantly correlated with PAPAS in tumour tissues. PAPAS overexpression in vitro was associated with miR-34a inhibition, while miR-34a failed to significantly affect PAPAS levels. PAPAS overexpression promoted in vitro migration and invasion of TNBC cells, while miR-34a overexpression was inhibitory. MiR-34a overexpression decreased the enhanced cell migration and invasion associated with PAPAS overexpression. PAPAS overexpression showed no significant effects on cancer-cell proliferation.

Conclusion

LncRNA PAPAS may promote TNBC by downregulating miR-34a.

A Genetic Variant of miR-34a Contributes to Susceptibility of Ischemic Stroke Among Chinese Population

miRNAs are small non-coding RNAs modulating gene expression, and variants in miRNA genes are involved in the pathogenesis of ischemic stroke (IS). However, the effect of miR-34a polymorphisms on IS susceptibility has rarely been reported. In the present study, we investigated the association between rs12128240, rs2666433, and rs6577555 of the miR-34a gene and IS susceptibility. Snapshot assay was used to detect miR-34a polymorphisms in 548 IS patients and 560 controls. Relative expression of miR-34a was measured by quantitative real-time PCR. We found that rs2666433 was associated with a significantly increased risk of IS (AA vs. GG: OR = 1.61, 95% CI = 1.05-2.52, P = 0.031; AA vs. GG+GA: OR = 1.58, 95% CI = 1.05-2.45, P = 0.026). For the IS subtypes, rs2666433 was associated with large artery atherosclerosis (AA vs. GG: OR = 2.09, 95% CI = 1.16-3.51, P = 0.007; AA vs. GG+GA: OR = 2.02, 95% CI = 1.15-3.33, P = 0.007; A vs. G: OR = 1.36, 95% CI = 1.07-1.81, P = 0.021). Additionally, the level of miR-34a was significantly up-regulated in IS patients compared to the controls (P < 0.001), and patients with rs2666433 AA genotype had a higher level of miR-34a than those with GG+GA genotypes (P < 0.001). Furthermore, increased level of homocysteine was observed in IS patients compared to the controls (P < 0.001), especially in patients carrying the rs2666433AA genotype compared to those carrying the rs2666433 GG+GA genotypes (P < 0.001). However, no significant association between rs12128240 or rs6577555 and IS was found. Collectively, our study found the association between miR-34a polymorphisms and the risk of IS among the Chinese population. The results may provide an explanation for etiology of IS and a potential biomarker or therapeutic target for IS. HIGHLIGHTS-MiR-34a rs2666433 polymorphism was associated with an increased risk of ischemic stroke.-The level of miR-34a was significantly up-regulated in ischemic stroke patients compared with controls, and patients with rs2666433 AA genotype had a higher level miR-34a than those with GG+GA genotypes.-Furthermore, increased level of homocysteine was showed in IS patients compared to controls, and in patients carrying the rs2666433AA compared to those carrying the rs2666433 GG+GA.

Roles of MicroRNA-34a in Epithelial to Mesenchymal Transition, Competing Endogenous RNA Sponging and Its Therapeutic Potential

MicroRNA-34a (miR-34a), a tumor suppressor, has been reported to be dysregulated in various human cancers. MiR-34a is involves in certain epithelial-mesenchymal transition (EMT)-associated signal pathways to repress tumorigenesis, cancer progression, and metastasis. Due to the particularity of miR-34 family in tumor-associated EMT, the significance of miR-34a is being increasingly recognized. Competing endogenous RNA (ceRNA) is a novel concept involving mRNA, circular RNA, pseudogene transcript, and long noncoding RNA regulating each other’s expressions using microRNA response elements to compete for the binding of microRNAs. Studies showed that miR-34a is efficient for cancer therapy. Here, we provide an overview of the function of miR-34a in tumor-associated EMT. ceRNA hypothesis plays an important role in miR-34a regulation in EMT, cancer progression, and metastasis. Its potential roles and challenges as a microRNA therapeutic candidate are discussed. As the negative effect on cancer progression, miR-34a should play crucial roles in clinical diagnosis and cancer therapy.

LncRNAs in ovarian cancer

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

LINC01118 Modulates Paclitaxel Resistance of Epithelial Ovarian Cancer by Regulating miR-134/ABCC1

BACKGROUND Epithelial ovarian cancer (EOC) has a high mortality rate and is a common malignant tumor of women, seriously impairing health. Chemoresistance is one of the major causes of poor prognosis. Therefore, analyzing the molecular mechanism of paclitaxel resistance has great significance. MATERIAL AND METHODS We analyzed aberrantly expressed lncRNAs in chemoresistant EOC cells by microarray and confirmed LINC01118 expression by real-time PCR. The paclitaxel sensitivity alternation was analyzed by MTS, flow cytometry, and Transwell assay, while wound healing assays were performed to assess apoptosis, migration, and invasion in vitro. The interaction between LINC01118 and miR-134 was confirmed by luciferase assay. RESULTS LINC01118 was highly expressed in EOC tissues and chemoresistant cells. Biological function experiments showed LINC01118 could facilitate paclitaxel resistance and promote migration and invasion while inhibiting apoptosis of EOC cells. Moreover, LINC01118 targets miR-134 and then affects ABCC1 expression. CONCLUSIONS LINC01118 acted as an oncogene and modulated EOC paclitaxel sensitivity by regulating miR-134/ABCC1.

Long non-coding RNAs in ovarian cancer

Long non-coding RNAs (lncRNAs) refer to functional cellular RNAs molecules longer than 200 nucleotides in length. Unlike microRNAs, which have been widely studied, little is known about the enigmatic role of lncRNAs. However, lncRNAs have motivated extensively attention in the past few years and are emerging as potentially important regulators in pathological processes, including in cancer. We now understand that lncRNAs play role in cancer through their interactions with DNA, protein, and RNA in many instances. Moreover, accumulating evidence has recognized that large classes of lncRNAs are functional for ovarian cancer. Nevertheless, the biological phenomena and molecular mechanisms of lncRNAs in ovarian cancer remain to be better identified. In this review, we outline the dysregulated expression of lncRNAs and their potential clinical implications in ovarian cancer, with a particular emphasis on discussing the well characterized mechanisms underlying lncRNAs in ovarian cancer.