The lncRNA CCAT1 upregulates TGFβR1 via sponging miR-490-3p to promote TGFβ1-induced EMT of ovarian cancer cells

Role of exosomal non‑coding RNAs in ovarian cancer (Review)

Ovarian cancer (OC) is a common gynecological disease with a high mortality rate worldwide due to its insidious nature and undetectability at an early stage. The standard treatment, combining platinum‑based chemotherapy with cytoreductive surgery, has suboptimal results. Therefore, early diagnosis of OC is crucial. All cell types secrete extracellular vesicles, particularly exosomes. Exosomes, which contain lipids, proteins, DNA and non‑coding RNAs (ncRNAs), are novel methods of intercellular communication that participate in tumor development and progression. ncRNAs are categorized by size into long ncRNAs (lncRNAs) and small ncRNAs (sncRNAs). sncRNAs further include transfer RNAs, small nucleolar RNAs, PIWI‑interacting RNAs and microRNAs (miRNAs). miRNAs inhibit protein translation and promote messenger RNA (mRNA) cleavage to suppress gene expression. By sponging downstream miRNAs, lncRNAs and circular RNAs can regulate target gene expression, thereby weakening the interactions between miRNAs and mRNAs. Exosomes and exosomal ncRNAs, commonly present in human biological fluids, are promising biomarkers for OC. The present article aimed to review the potential role of exosomal ncRNAs in the diagnosis and prognosis of OC by summarizing the characteristics, processes, roles and isolation methods of exosomes and exosomal ncRNAs.

Prognostic significance of non-coding RNAs related to the tumorigenic epithelial-mesenchymal transition (EMT) process among ovarian cancer patients: A systematic review and meta-analysis

Introduction

Ovarian cancer is the seventh most prevalent cancer among women. It has high mortality and morbidity and imposes a great burden on healthcare systems worldwide. Unraveling the mechanisms behind the Epithelial-Mesenchymal Transition and finding a panel for predicting the prognosis of the disease may help find the appropriate treatment approaches for the management of the disease. The overarching aim of this systematic review was to define a panel of different types of EMT-associated non-coding RNAs (ncRNAs) with significant prognostic value in all types of ovarian cancers.

Methods

We searched PubMed, Web of Science, Scopus, and Embase till Jun 2024 to retrieve relevant papers. Two independent reviewers screened papers, and discrepancies were resolved by consensus. Publications related to the dysregulation of different types of ncRNAs, including microRNAs, lncRNAs, and circRNAs, only in patients with ovarian cancer were included. The participation of ncRNAs in epithelial-mesenchymal transformation should be assessed via methods evaluating different EMT-related proteins. To assess the quality and risk of bias for the included case-control and cohort studies, refined Newcastle-Ottawa Scale (NOS) and Quadas-2 were recruited. A bivariate meta-analysis was performed to analyze extracted data.

Results

A total of 37 studies with overall 42 non-coding RNAs (15 microRNA, 24 long non-coding RNAs, and 3 circular RNAs) were entered into the analysis. Overall diagnostic odds ratio for ncRNAs in lymph node metastasis, distant metastasis, TNM stage, and clinical stage were 4.19, 3.80, 6.52, and 3.97, respectively. Also, a hazard ratio of 1.39 (P = 0.32) for overall survival was observed. Bioinformatic analyses on the Pan-cancer database demonstrated a significant correlation between low expression of miRNA and high expression of lncRNAs with poor prognosis of ovarian cancer.

Conclusion

Based on the results, the defined panel of ncRNAs can properly predict prognostic factors related to EMT in ovarian cancer without involving potentially invasive methods.

The long non-coding RNA CCAT1 promotes erlotinib resistance in cholangiocarcinoma by inducing epithelial-mesenchymal transition via the miR-181a-5p/ROCK2 axis

Cholangiocarcinoma (CCA) is a common malignancy of the digestive system, and its treatment is greatly challenged by rising chemoresistance. Long non-coding RNAs (lncRNAs) have been shown to play critical roles in the development of drug resistance in tumors. However, the role of the lncRNA CCAT1 in erlotinib resistance in CCA remains unclear. In this investigation, we identified CCAT1 as a pivotal factor contributing to erlotinib resistance in CCA. Furthermore, we uncovered that lncRNA CCAT1 modulated epithelial-mesenchymal transition (EMT) through Rho-associated coiled-coil-forming protein kinase 2 (ROCK2), thereby conferring erlotinib resistance upon CCA cells. Mechanistically, we demonstrated that miR-181a-5p interacted with CCAT1 to modulate the expression of ROCK2. Collectively, these findings shed light on the significant role of CCAT1 in the development of erlotinib resistance in CCA. The functional suppression of CCAT1 holds promise in enhancing the sensitivity to erlotinib by reversing EMT through the miR-181a-5p/ROCK2 signaling pathway. These findings provide valuable insights into the mechanisms underlying erlotinib resistance in CCA and the potential strategies for its treatment.

LncRNA CCAT1 knockdown suppresses tongue squamous cell carcinoma progression by inhibiting the ubiquitination of PHLPP2

Tongue squamous cell carcinoma (TSCC) is prevailing malignancy in the oral and maxillofacial region, characterized by its high frequency. LncRNA CCAT1 can promote tumorigenesis and progression in many cancers. Here, we investigated the regulatory mechanism by which CCAT1 influences growth and metastasis of TSCC. Levels of CCAT1, WTAP, TRIM46, PHLPP2, AKT, p-AKT, and Ki67 in TSCC tissues and cells were assessed utilizing qRT-PCR, Western blot and IHC. Cell proliferation, migration, and invasion were evaluated utilizing CCK8, colony formation, wound healing and transwell assays. Subcellular localization of CCAT1 was detected utilizing FISH assay. m6A level of CCAT1 was assessed using MeRIP. RNA immunoprecipitation (RIP), Co-immunoprecipitation (Co-IP) and RNA pull down elucidated binding relationship between molecules. Nude mouse tumorigenesis experiments were used to verify the TSCC regulatory function of CCAT1 in vivo. Metastatic pulmonary nodules were observed utilizing hematoxylin and eosin (HE) staining. CCAT1 silencing repressed TSCC cell proliferation, migration and invasion. Expression of CCAT1 was enhanced through N6-methyladenosine (m6A) modification of its RNA, facilitated by WTAP. Moreover, IGF2BP1 up-regulated CCAT1 expression by stabilizing its RNA transcript. CCAT1 bond to PHLPP2, inducing its ubiquitination and activating AKT signaling. CCAT1 mediated the ubiquitination and degradation of PHLPP2 by TRIM46, thereby promoting TSCC growth and metastasis. CCAT1/TRIM46/PHLPP2 axis regulated proliferation and invasion of TSCC cells, implying that CCAT1 would be a novel therapeutic target for TSCC patients.

The Role of EMT-Related lncRNAs in Ovarian Cancer

Ovarian cancer (OC) is one of the deadliest cancers worldwide; late diagnosis and drug resistance are two major factors often responsible for high morbidity and treatment failure. Epithelial-to-mesenchymal transition (EMT) is a dynamic process that has been closely linked with cancer. Long non-coding RNAs (lncRNAs) have been also associated with several cancer-related mechanisms, including EMT. We conducted a literature search in the PubMed database in order to sum up and discuss the role of lncRNAs in regulating OC-related EMT and their underlying mechanisms. Seventy (70) original research articles were identified, as of 23 April 2023. Our review concluded that the dysregulation of lncRNAs is highly associated with EMT-mediated OC progression. A comprehensive understanding of lncRNAs' mechanisms in OC will help in identifying novel and sensitive biomarkers and therapeutic targets for this malignancy.

Sequential-delivery nanocomplex for combined anti-angiogenesis and gene therapy against colorectal cancer

Neovascularization can provide tumors with essential nutrients and oxygen, as well as maintain a microenvironment for tumor cell growth. In this study, we combined anti-angiogenic therapy and gene therapy for synergistic anti-tumor therapy. We co-delivered the vascular endothelial growth factor receptor inhibitor fruquintinib (Fru) and small interfering RNA CCAT1 (siCCAT1) inhibiting epithelial-mesenchymal transition using 1,2-distearoyl-snglycero-3-phosphoethanolamine-N- [methoxy (polyethylene glycol)] with a pH-responsive benzoic imine linker bond (DSPE-Hyd-mPEG) and polyethyleneimine-poly (d, l-lactide) (PEI-PDLLA) nanocomplex (Fru and siCCAT1 co-delivery NP, FCNP). Due to the characteristics of pH-response, DSPE-Hyd-mPEG removed from FCNP after enrichment at the tumor site, which had a protective effect in the body. Meanwhile, Fru acting on the peritumor blood vessels was rapidly released, and then the nanoparticles loaded with siCCAT1 (CNP) was engulfed by cancer cells and facilitate the successful lysosomal escape of siCCAT1 in, playing the role of silencing CCAT1. Efficient silencing of CCAT1 by FCNP was observed, and simultaneously, the expression of VEGFR-1 was also down-regulated. Furthermore, FCNP elicited significant synergistic antitumor efficacy via anti-angiogenesis and gene therapy in the SW480 subcutaneous xenograft model with favorable biosafety and biocompatibility during the treatment. Overall, FCNP was considered a promising strategy for the combined anti-angiogenesis-gene treatment against colorectal cancer.

LncRNA HCG11 represses ovarian cancer cell growth via AKT signaling pathway

AIM

Ovarian cancer is a main contributor of cancer-relevant deaths among women worldwide due to high incidence and mortality. Mounting evidence has unveiled that lncRNAs play critical roles in malignancies, including ovarian cancer. Although the tumor suppressor function of HCG11 in prostate cancer and glioma has been proved, investigations on HCG11 role in ovarian cancer are still scarce.

METHODS

Gene or protein expression was quantified by RT-qPCR or western blot. HCG11 effects on ovarian cancer were assessed by functional assays. Bioinformatics analysis and mechanism experiments were implemented to identify the association among HCG11, miR-1270, and PTEN.

RESULTS

HCG11 was weakly expressed in ovarian cancer and functioned as a tumor suppressor in ovarian cancer by retarding cell proliferation, migration, and EMT. Besides, HCG11 could bind to miR-1270 and PTEN was a target gene of miR-1270. Mechanically, HCG11 competitively bound with miR-1270 to upregulate PTEN. From rescue experiments, HCG11 impeded AKT/mTOR pathway to retard ovarian cancer cell growth by miR-1270/PTEN.

CONCLUSIONS

HCG11 was a tumor suppressor in ovarian cancer cells and additionally, HCG11 regulated AKT/mTOR pathway to hinder ovarian cancer cell growth via modulating miR-1270/PTEN, indicating that HCG11 may represent a promising target for effective treatment of ovarian cancer patients.

What is beyond LncRNAs in breast cancer: A special focus on colon cancer-associated Transcript-1 (CCAT-1)

Long non-coding RNAs (LncRNAs) play a vital role in the process of malignant transformation. In breast cancer (BC), lncRNAs field is currently under intensive investigations. Yet, the role of lncRNAs as promising diagnostic and/or prognostic biomarkers and as therapeutic target/tool among BC patients still needs a special focus from the biomedical scientists. In BC, triple negative breast cancer patients (TNBC) are the unlucky group as they are always represented with the worst prognosis and the highest mortality rates. For that reason, a special focus on TNBC and associated lncRNAs was addressed in this review. Colon cancer-associated transcript 1 (CCAT-1) is a newly discovered oncogenic lncRNA that has been emerged as a vital biomarker for diagnosis, prognosis and therapeutic interventions in multiple malignancies and showed differential expression among TNBC patients. In this review, the authors shed the light onto the general role of lncRNAs in BC and the specific functional activities, molecular mechanisms, competing endogenous ncRNA role of CCAT-1 in TNBC.

LINC01094 promotes the invasion of ovarian cancer cells and regulates the Wnt/β-catenin signaling pathway by targeting miR-532-3p

Long non-coding RNAs (lncRNAs) participate in the development of ovarian cancer (OC). The present study aimed to explore the roles of long intergenic non-protein coding RNA 1094 (LINC01094) in OC. LINC01094 and microRNA (miR)-532-3p expression in OC tissues and cells were measured using reverse transcription-quantitative PCR. Cell migration and invasion were detected using wound healing assays and Transwell assays, respectively. The binding of LINC01094 or β-catenin to miR-126-5p was detected using a Dual-luciferase reporter assay, and protein expression was confirmed using western blot analysis. The expression level of LINC01094 in patients with OC was higher in OC tissues compared with in adjacent tissues, and LINC01094 was upregulated in OC cell lines. In addition, LINC01094 overexpression promoted the viability, migration, invasion and cell cycle progression of OC cells, and inhibited OC cell apoptosis. Moreover, LINC01094 negatively regulated miR-532-3p in OC cells and tissues. miR-532-3p overexpression decreased the viability, migration, invasion and cell cycle progression of OC cells alongside downregulation of Wnt/β-catenin signaling pathway protein expression, as well as increasing OC cell apoptosis. Inhibition of LINC01094 with small interfering (si)-LINC01094 and overexpression of LINC01094 respectively reversed the effect of miR-532-3p inhibitor and mimics on OC cells. miR-532-3p could directly target β-catenin, and miR-532-3p inhibitor increased β-catenin expression, while si-LINC01094 attenuated this effect. In addition, LINC01094 overexpression promoted tumor growth in vivo by regulating miR-532-3p. Taken together, LINC01094 promoted the growth, migration, invasion and Wnt/β-catenin signaling pathway expression of OC cells by modulating miR-532-3p.

Metastatic colorectal cancer: Perspectives on long non-coding RNAs and promising therapeutics

Metastatic colorectal cancer (mCRC) has long been lethal despite the continuous efforts of researchers worldwide to discover and improve therapeutic regimens. Thanks to the emergence of long non-coding RNAs (lncRNAs), which has strongly reshaped our inherent perspectives on the pathophysiological patterns of disease, research in the field has been reinvigorated. Here, we focus on current understanding of the modes of action of lncRNAs, and review their regulatory roles in metastatic colorectal cancer, and discuss correlated potential lncRNA-based therapeutics. All of the discussed studies share clear and promising perspectives on future diagnostic and therapeutic remedies for metastatic colorectal cancer.

Long non-coding RNA miR155HG silencing restrains ovarian cancer progression by targeting the microRNA-155-5p/tyrosinase-related protein 1 axis

Ovarian cancer (OC) is the third commonest gynecological malignancy worldwide. The long non-coding (lnc)RNA microRNA (miR)155HG functions as an oncogene in different human cancers. However, the function and molecular mechanism of miR155HG in OC remain elusive. The present study indicated that the expression levels of miR155HG and tyrosinase-related protein 1 (TYRP1) were significantly increased, whereas that of miR155-5p was decreased in OC tissues and cells, as detected by real-time quantitative polymerase chain reaction. It was demonstrated that knockdown of miR155HG markedly inhibited OC cell viability, migration and invasion while promoting apoptosis, as indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, Transwell and western blot assays. Mechanistically, it was revealed that miR155HG and TYRP1 were both targeted by miR-155-5p with complementary binding sites in the 3' untranslated region. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR155HG, miR-155-5p and TYRP1. In addition, the interaction between miR155HG and miR-155-5p was further demonstrated by radioimmunoprecipitation and pull-down assays. In addition, feedback approaches determined that miR-155-5p inhibition or TYRP1 overexpression markedly reversed the inhibitory effects of miR155HG knockdown on OC cell viability, migration and invasion as well as weakened the promotive effect of miR155HG knockdown on OC cell apoptosis. Thus, miR155HG silencing inhibited the malignant biological behavior of OC cells by targeting the miR-155-5p/TYRP1 axis. The present study provides novel insights into the underlying mechanism of OC progression.

LncRNA GAS5 inhibits the proliferation and invasion of ovarian clear cell carcinoma via the miR-31-5p/ARID1A axis

To investigate the role of the lncRNA growth arrest special 5 (GAS5) in ovarian clear cell carcinoma (OCCC), we measured the expression of GAS5 and miR-31-5p in OCCC tissue samples and OCCC cell lines using RT-qPCR. MTT and colony formation assays were used to measure cell viability and colony formation ability. Cell invasion was determined by Transwell assays. The binding between GAS5 and miR-31-5p as well as miR-31-5p and ARID1A was determined by dual-luciferase reporter assays. The ARID1A protein levels were detected using western blotting. Kaplan-Meier curves were used for the analysis of the 5-year survival rate of patients with OCCC. GAS5 and ARID1A levels were significantly decreased, while miR-31-5p levels were strongly elevated in the OCCC tissues and cell lines. Patients with lower GAS5/ARID1A levels had shorter overall survival times. Overexpression of GAS5 or inhibition of miR-31-5p suppressed cell viability and invasion of OCCC cells and upregulated the protein levels of ARID1A. Moreover, overexpression of miR-31-5p reversed the effects of overexpression of GAS5. Cotransfection with pcDNA3.1-GAS5 and miR-31-5p inhibitor led to the lowest cell viability and cell invasion rates. A dual-luciferase reporter assay was performed to confirm the target relationship between GAS5 and miR-31-5p, as well as between miR-31-5p and ARID1A. LncRNA GAS5 inhibited cell viability and invasion of OCCC through activation of ARID1A by sponging miR-31-5p.

LncRNA CCAT1 promotes prostate cancer cells proliferation, migration, and invasion through regulation of miR-490-3p/FRAT1 axis

Prostate cancer (PCa) is a prevalent cancer in males, with high incidence and mortality. Recent studies have shown the crucial role of long non-coding RNA (lncRNA) in PCa. Here, we aimed to explore the functional roles and inner mechanisms of lncRNA CCAT1 in PCa cells. qRT-PCR results showed that CCAT1 was upregulated in PCa tissues and cells. Functional assays demonstrated that CCAT1 knockdown suppressed cell proliferation, migration, invasion, yet promoted apoptosis, while CCAT1 promotion showed the opposite results. We also found that CCAT1 negatively regulated miR-490-3p expression and subsequently regulated FRAT1 expression. Inhibition of miR-490-3p or up-regulation of FRAT1 reversed the suppressive effects of CCAT1 knockdown on the PCa cells. In conclusion, CCAT1 regulated FRAT1 expression through miR-490-3p and then promote the PCa cells proliferation, migration, and invasion, which reveals the oncogenic function of CCAT1 in PCa progress.

MicroRNA-490-3p and -490-5p in carcinogenesis: Separate or the same goal?

MicroRNA (miR)-490-3p and miR-490-5p, located on chromosome 7q33, are two independent mature products of miR-490 exerting distinct effects on tumor progression. miR-490-3p and miR-490-5p possess antitumor properties. miR-490-3p dysfunction has been associated with malignancies including colorectal cancer, while the abnormal function of miR-490-5p has been more considerably associated with bladder cancer (for example). At present, there are 30 and 11 target genes of miR-490-3p and miR-490-5p, respectively, that have been experimentally verified, of which the cyclin D1 (CCND1) gene is a common target. Through these target genes, miR-490-3p and miR-490-5p are involved in 7 and 3 signaling pathways, respectively, of which only 2 are shared regulatory signaling pathways. The present review introduces two competing endogenous RNA (ceRNA) regulatory networks centered on miR-490-3p and miR-490-5p. These networks may be important promoters of tumor cell proliferation, invasiveness, metastatic potential and apoptosis. Unlike miR-490-5p, miR-490-3p plays a unique role in promoting cancer. However, both are promising molecular markers for early cancer diagnosis and prognosis. In addition, miR-490-3p was also found to be associated with the chemical resistance of cisplatin and paclitaxel. The present review focuses on the abnormal expression of miR-490-3p and miR-490-5p in different tumor types, and their complex ceRNA regulatory networks. The clinical value of miR-490-3p and miR-490-5p in cancer diagnosis, prognosis and treatment is also clarified, and an explanation for the opposing effects of miR-490-3p in tumor research is provided.

LncRNA CCAT1 sponges miR-218-5p to promote EMT, cellular migration and invasion of retinoblastoma by targeting MTF2

Retinoblastoma (RB) is the primary neoplasms of the retina that is most common in pediatrics age. Long non-coding RNAs (lncRNAs) has been noticed for strong relation to the occurrence and progress of retinoblastoma. Previously, we have demonstrated that lncRNA colon cancer-associated transcript 1 (CCAT1) in two RB cell lines SO-RB50 and Y79 was obviously overexpressed, and notably, lncRNA CCAT1 attenuated miR-218-5p expressionand induced proliferation, cell migration and invasion. But, how lncRNA CCAT1 acts in RB development and the potential molecular mechanisms remain to be determined. In this study, the expression levels of lncRNA CCAT1 and miR-218-5p were evaluated in RB tissues by Q-PCR, which established the results in the cell lines. Further, lncRNA CCAT1 was shown to promote epithelial-to-mesenchymal transition (EMT), cellular migration and invasion of RB cells by functional analysis of downregulation and overexpression of lncRNA CCAT1 with specific siRNA and pcDNA transfection. By performing bioinformatics and dual luciferase reporter assay, we verified the direct interaction between lncRNA CCAT1 and miR-218-5p. Besides, bioinformatics analysis indicated that metal regulatory transcription factor 2 (MTF2) might be a potent novel target for miR-218-5p, which was further validated with luciferase reporter assay, Q-PCR and also Western blot analysis. Functional analysis and rescue analysis showed that lncRNA CCAT1 via competitive binding to miR-218-5p to modulate MTF2 expression thus accelerate EMT, cell migration and invasion of RB. In conclusion, here we identified the lncRNA CCAT1/miR-218-5p/MTF2 axis in RB cell lines. Our investigations on the function of lncRNA CCAT1 and the roles of the related molecules hint a novel potential target fo RB therapy.

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.

miR-373-3p inhibits epithelial-mesenchymal transition via regulation of TGFβR2 in choriocarcinoma

AIM

Previous studies have indicated that early metastasis is a major cause of mortality in patients with choriocarcinoma. However, what determines whether early metastasis of choriocarcinoma has occurred is unknown. The emerging role of miRNA in regulating cancer development and progression has been recognized. miR-373 has been shown to play pivotal roles in tumorigenesis and metastasis. However, whether miR-373 functions to promote choriocarcinoma metastasis is not clear. The purpose of this study is to determine the function of miR-373-3p in the progression of this cancer.

METHODS

In this study, we first compared epithelial-mesenchymal transition (EMT)-related markers, which were inversely correlated with miR-373-3p expression in trophoblast and choriocarcinoma cell lines. Using PCR and Western blot, upregulation of miR-373-3p was observed to inhibit EMT progression. Similarly, gain- and loss-of-function studies revealed that ectopic miR-373-3p overexpression inhibited the migration by transwell methods of choriocarcinoma cells.

RESULTS

Our results revealed that miR-373-3p acted as an EMT inhibitor in JEG-3 and JAR cells; this was due to its mediation of the transforming growth factor-β (TGFβ) signaling pathway, which was responsible for EMT. miRNA microarray analysis demonstrated that miR-373-3p interacted with the 3' untranslated region of TGFβR2 mRNA, and then Western blot and dual-luciferase reporter gene assays verified this interaction.

CONCLUSION

Our findings suggest that miR-373-3p upregulation partly accounts for TGFβR2 downregulation and leads to a restraint of EMT and migration. miR-373-3p may therefore serve as a valuable potential target in the treatment of choriocarcinoma.

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.

The Impact of Non-coding RNAs in the Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is a course of action that enables a polarized epithelial cell to undertake numerous biochemical alterations that allow it to adopt features of mesenchymal cells such as high migratory ability, invasive properties, resistance to apoptosis, and importantly higher-order formation of extracellular matrix elements. EMT has important roles in implantation and gastrulation of the embryo, inflammatory reactions and fibrosis, and transformation of cancer cells, their invasiveness and metastatic ability. Regarding the importance of EMT in the invasive progression of cancer, this process has been well studies in in this context. Non-coding RNAs (ncRNAs) have been shown to exert critical function in the regulation of cellular processes that are involved in the EMT. These processes include regulation of some transcription factors namely SNAI1 and SNAI2, ZEB1 and ZEB2, Twist, and E12/E47, modulation of chromatin configuration, alternative splicing, and protein stability and subcellular location of proteins. In the present paper, we describe the influence of ncRNAs including microRNAs and long non-coding RNAs in the EMT process and their application as biomarkers for this process and cancer progression and their potential as therapeutic targets.

EZH2-mediated lncRNA ABHD11-AS1 promoter regulates the progression of ovarian cancer by targeting miR-133a-3p

Long-chain noncoding RNAs (lncRNAs) are involved in a wide range of biological and pathological processes in ovarian cancer. The purpose of this study was to investigate the effects of EZH2-mediated ABHD11-AS1 promoter on the pathogenesis of ovarian cancer. The expression levels of EZH2, ABHD11-AS1 and miR-133a-3p were examined in ovarian cancer tissues using reverse transcription-quantitative PCR. Cell proliferation was evaluated using cell counting kit 8 assay, and cell invasion/migration was determined using a Transwell assay. Cell apoptosis was evaluated using flow cytometry. Dual luciferase assay was performed to confirm the interaction between ABHD11-AS1 and miR-133a-3p. The binding site of H3K27me3 on ABHD11-AS1 promoter was confirmed by ChIP. The expression of ABHD11-AS1 was significantly upregulated in ovarian cancer samples, and its levels were closely associated with lymph node metastasis, tumor stage and 3-year survival rate. Furthermore, interference of ABHD11-AS1 suppressed the proliferation, migration and invasion of ovarian cancer cells, while cell apoptosis was promoted. Additionally, miR-133a-3p could be a novel target of ABHD11-AS1, and EZH2-mediated H3K27me3 protein might bind to ABHD11-AS1 promoter directly. Moreover, rescue experiments indicated that the effects caused by ABHD11-AS1 knockdown on the malignant characteristics of ovarian cancer cells were notably enhanced by miR-133a-3p mimics, whereas the influences on cell growth and metastasis induced by overexpressed ABHD11-AS1 were abrogated by the restoration of miR-133a-3p expression. In summary, EZH2-mediated enrichment of H3K27me3 on ABHD11-AS1 promoter could regulate the progression of ovarian cancer via miR-133a-3p. Therefore, EZH2/ABHD11-AS1/miR-133a-3p axis might be a putative candidate for targeted treatment of ovarian cancer.

Long non-coding RNAs in recurrent ovarian cancer: Theranostic perspectives

Nearly 70% of ovarian cancer (OC) patients experience recurrence within the first 2 years after initial treatment. Emerging evidence indicates that long non-coding RNAs (lncRNAs) play a pivotal role in the pathogenesis of OC progression, resistance to therapy and recurrent OC (ROC). Transcriptome profiling studies have reported differential expression patterns of lncRNAs in OC which are related to increased cell invasion, metastasis and drug resistance. In this review, we highlighted the roles of lncRNAs in OC progression and outlined the potential molecular mechanisms by which lncRNAs impact on ROC. Recent advances using lncRNAs as potential biomarkers for screening, detection, prediction, response to therapy and as therapeutic targets are discussed.

lncRNA CCAT1/miR-490-3p/MAPK1/c-Myc positive feedback loop drives progression of acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a frequently diagnosed malignancy in adults. Long non-coding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) has been well known to play vital roles in multiple malignancies including AML. Unfortunately, the detailed mechanism of CCAT1 in AML progression remains obscure. In this study, we demonstrated that CCAT1 was up-regulated in AML samples while its target, miR-490-3p, was relatively down-regulated. CCAT1 markedly increased viability and metastasis of AML cells, while miR-490-3p had opposite effects. CCAT1 could specifically bind to miR-490-3p and reduce its expression and activity, and MAPK1 was a target gene of miR-490-3p. Overexpressed CCAT1 could induce MAPK1 expression and c-Myc reciprocally increased CCAT1 expression. Our data implied that miR-490-3p could be a novel therapeutic target for AML, and highlights the crucial role of CCAT1/miR-490-3p/MAPK1/c-Myc positive feedback loop in AML progression.

Long non-coding RNA CCAT1 sponges miR-490 to enhance cell proliferation and migration of non-small cell lung cancer

Background

Non‐small cell lung cancer (NSCLC) accounts for 85% of lung cancer which is the most frequently diagnosed malignancy in China. Colon cancer associated transcript 1 (CCAT1) acts as an oncogene in enhancing tumor progression. However, the effects of CCAT1 in NSCLC remain unclear. The purpose of this study was to explore the role of CCAT1 in NSCLC.

Methods

Wound healing and transwell assays were performed to measure cell migration. RT‐qPCR was employed to calculate the mRNA level of CCAT1 and miR‐490.

Results

High expression of CCAT1 was observed in NSCLC tissues and cells, with low expression of miR‐490. CCAT1 promoted the proliferation and metastasis of H1299 and A549 cells, while miR‐490 had the opposite effect. CCAT1 could specifically bind to miR‐490 and regulate its expression. MiR‐490 partially reversed the inhibitory effect of CCAT1 on cell proliferation and metastasis.

Conclusions

The CCAT1/miR‐490 molecular axis has been shown to be important for the treatment of NSCLC.

TMT-based quantitative proteomic analysis of antitumor mechanism of Sporisorium reilianum polysaccharide WM-NP-60 against HCT116 cells

Sporisorium reilianum is an active edible and medicinal phytopathogenic fungus. Our study indicated that the S. reilianum polysaccharide WM-NP-60 could inhibit the growth of HCT116 cells in a dose-dependent manner. In addition, WM-NP-60 could trigger the cell cycle of HCT116 arrest at the G₁ phase and induce its apoptosis. In order to explore the anti-tumor mechanism of WM-NP-60, TMT-based quantitative proteomic analysis was used. Results indicated that 369 differentially expressed proteins including 240 up-regulated and 129 down-regulated proteins in WM-NP-60 treated HCT116 cells compared with normal HCT116 cells. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that 192 pathways were enriched containing 15 metabolic pathways with significant difference (P < 0.05). The levels of mRNA and protein up-regulated TGFβR1, P107, DP1 and down-regulated THBS1 related to TGF-β signaling pathway were verified with qRT-PCR and Western Blot (WB). These findings will provide theoretical basis for the important role of fungal polysaccharides in the field of tumor 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.

RP11-81H3.2 Acts as an Oncogene via microRNA-490-3p Inhibition and Consequential Tankyrase 2 Up-Regulation in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a serious threat to human lives and is usually diagnosed at the late stages. Recently, there has been a rapid advancement in the treatment options for HCC, but novel therapeutic targets are still needed, especially for precision medicine.

AIMS

We aimed to investigate the involvement of non-coding RNA RP11-81H3.2 in HCC.

METHODS

The expression of RP11-81H3.2 was examined in the blood samples of HCC patients, and in the human HCC cell lines, including HepG2, Smmc-7721, and Huh7. Cell proliferation was determined using the CCK-8 and EdU assay, and cell invasion and migration were determined using the transwell/wound healing assay. The effects of RP11-81H3.2 knockdown on in vivo tumor growth were evaluated utilizing the nude mice HepG2 tumor xenograft model.

RESULTS

Here, we have identified a long non-coding RNA, RP11-81H3.2, which is enriched in HCC and can promote its proliferation, migration, and invasion both in vitro and in vivo. In addition, our results showed that RP11-81H3.2 binds to and regulate miR-490-3p expression in the HCC cells. Moreover, we found that RP11-81H3.2 regulates the expression of TNKS2 via miR-490-3p. Further, we found that RP11-81H3.2 and miR-490-3p form a regulatory loop; the release of RP11-81H3.2 leads to the suppression of miR-490-3p expression, thus, further enhancing the expression of RP11-81H3.2.

CONCLUSIONS

Our data have provided a novel target for the diagnosis and treatment of HCC, and sheds light on the lncRNA-miRNA regulatory nexus that can control the HCC related pathogenesis.

LncRNA SNHG6 Induces Epithelial-Mesenchymal Transition of Pituitary Adenoma Via Suppressing MiR-944

Background:

Pituitary adenoma (PA) is a common primary brain tumor with invasive properties. Despite that long noncoding RNA (lncRNA) small nucleolar RNA host gene 6 (SNHG6) exerts oncogenic function in cancer cells and that miR-944 inhibits epithelial–mesenchymal transition (EMT) of cancer cells are well documented, few studies have explored the function and mechanism of SNHG6 and miR-944 in invasive pituitary adenoma (IPA).

Materials and Methods:

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expressions of SNHG6 and miR-944 in PA samples. Human PA cell line HP75 was used as a cell model. The biological effects of SNHG6 and miR-944 on HP75 cells were investigated with cell counting kit-8 (CCK-8) assay, Transwell assay, and scratch healing assay in vitro, respectively. Markers of EMT, including E-cadherin and vimentin, were detected by Western blot. Interactions between SNHG6 and miR-944, miR-944 and RAB11A were determined by bioinformatics analysis, qRT-PCR, and dual luciferase reporter assay.

Results:

SNHG6 was significantly upregulated in IPA samples, whereas miR-944 was downregulated. SNHG6 markedly promoted viability, migration, invasion, and EMT of PA cells, whereas miR-944 transfection had the opposite effects. SNHG6 could downregulate miR-944, and there was a negative correlation between SNHG6 expression and miR-944 expression in IPA samples. Besides, it was confirmed that miR-944 could pair with the 3′-untranslated region of RAB11A and repress its expression.

Conclusions:

This study authenticates that the SNHG6/miR-994/RAB11A axis plays a crucial role in regulating proliferation, migration, invasion, and EMT of IPA cells. SNHG6 and miR-994 can serve as novel valuable therapeutic targets for IPA.

CCAT1 promotes triple-negative breast cancer progression by suppressing miR-218/ZFX signaling

Long non-coding RNAs (lncRNAs) regulate cancer development and progression. Here, we investigated the role of the lncRNA CCAT1 in triple-negative breast cancer (TNBC). CCAT1 expression was higher in TNBC cells than normal breast epithelial cells. Additionally, CCAT1 expression was higher in TNBC patient tumor tissue than adjacent normal breast tissue. Silencing CCAT1 inhibited TNBC cell proliferation, migration, and invasion in vitro, and tumor growth and progression in vivo. Bioinformatics analysis revealed that microRNA-218 (miR-218) is a potential target of CCAT1. Silencing CCAT1 resulted in an increase in miR-218 expression and inhibited TNBC cell proliferation, migration, and invasion. Silencing miR-218 reversed the effects of CCAT1 knockdown on cell proliferation, migration, and invasion, suggesting that CCAT1 promotes TNBC progression by downregulating miR-218 expression. We identified the zinc finger protein ZFX as a putative downstream target of miR-218 through bioinformatics analysis. ZFX expression was higher in TNBC than normal breast cell lines and higher in TNBC tumor tissue than adjacent normal breast tissue. Overexpression of ZFX reversed the tumor-suppressive effects of miR-218 on TNBC cell proliferation, migration, and invasion. Our data indicate that CCAT1 promotes TNBC progression by targeting the miR-218/ZFX axis.

Knockdown of CYP24A1 Aggravates 1α,25(OH)2D3-Inhibited Migration and Invasion of Mouse Ovarian Epithelial Cells by Suppressing EMT

Epithelial-mesenchymal transition (EMT) bestows cancer cells with motile and invasive properties. But for ovarian tissues, EMT plays a physiological role in the postovulatory repair of ovary surface epithelial (OSE) cells. Accumulating data indicated that 1α,25(OH)₂D₃ decreased both the migration and invasion of various cancer cells by suppressing EMT. However, it remains unclear whether 1α,25(OH)₂D₃ inhibits the process of EMT during different stages of oncogenic transformation in mouse OSE (MOSE) cells. In present study, a spontaneous malignant transformation model of MOSE cells at three sequential stages (early, intermediate and late) was established in vitro first and then subjected to 1α,25(OH)₂D₃ treatment to investigate the effect of 1α,25(OH)₂D₃ on the oncogenic transformation of MOSE cells. We found that 1α,25(OH)₂D₃ significantly reduced the proliferation and invasion of late malignant transformed MOSE (M-L cells) cells by inhibiting EMT both in vitro and in vivo, but not in intermediate transformed (M-I) cells. Importantly, we found that the levels of CYP24A1 in M-I cells were dramatically higher than that in M-L cells following treatment with 1α,25(OH)₂D₃. Furthermore, we demonstrated that, in both M-I and M-L cells with CYP24A1 knockdown, 1α,25(OH)₂D₃ suppressed the proliferation and invasion, and reduced the expression of N-cadherin, Vimentin, β-catenin and Snail. In addition, knockdown of CYP24A1 suppressed EMT by increasing E-cadherin while decreasing N-cadherin, Vimentin, β-catenin and Snail. These findings provide support for inhibiting CYP24A1 as a potential approach to activate the vitamin D pathway in the prevention and therapy of ovarian cancer.

Long Non-coding RNA RP11-480I12.5 Promotes the Proliferation, Migration, and Invasion of Breast Cancer Cells Through the miR-490-3p-AURKA-Wnt/β-Catenin Axis

Background: RP11-480I12. 5 is a newly identified long non-coding RNA (lncRNA) that has never been studied in breast cancer (BC). The biological function of RP11-480I12.5 in breast carcinoma and its underlying mechanism are still unknown.

Methods: We scanned The Cancer Genome Atlas (TCGA) database and identified RP11-480I12.5 as one of the most dysregulated lncRNAs. The level of RP11-480I12.5 was assessed in BC tissue samples and BC cell lines. The prognostic value of RP11-480I12.5 expression was assessed using the Kaplan–Meier method. The biological influence of RP11-480I12.5 on BC cell lines was studied using proliferation and Transwell migration and invasion assays.

Results: RP11-480I12.5 expression was upregulated in data from both the TCGA database and our own database. Moreover, Kaplan–Meier and Cox proportional hazard analyses indicated that high RP11-480I12.5 expression was related to poor overall survival. Moreover, RP11-480I12.5 promoted the proliferation, migration, and invasion of BC. RP11-480I12.5 promoted the expression of AURKA and the activation of the downstream Wnt/β-catenin pathway by sponging the microRNA (miRNA) miR-490-3p.

Conclusion: Taken together, our results indicate that RP11-480I12.5 is associated with tumor progression in BCs. Our findings indicate that the lncRNA RP11-480I12.5 promotes the proliferation, migration, and invasion of BC cells through the miR-490-3p-AURKA-Wnt/β-catenin axis, which may serve as a therapeutic target in the future.

RHPN1-AS1 promotes cell proliferation and migration via miR-665/Akt3 in ovarian cancer

Recent efforts have revealed that long non-coding RNAs exert crucial roles in cancer initiation and progression. RHPN1-AS1 is a 2030 bp transcript from human chromosome 8q24, and involved in tumorigenesis in uveal melanoma and non-small cell lung cancer, but it remains unknown in ovarian cancer. This study focused on the role of RHPN1-AS1 in ovarian cancer and found that RHPN1-AS1 was up-regulated in ovarian cancer tissues and cell lines. Overexpression of RHPN1-AS1 promoted ovarian cancer cell proliferation, migration, and invasion. Mechanistically, overexpression of RHPN1-AS1 decreased the expression of miR-665 and subsequently promoted the expression of Akt3 at posttranscriptional level. Taken together, RHPN1-AS1 positively regulated the expression of Akt3 through sponging miR-665, and exerted an oncogenic role in ovarian cancer progression, and indicates that RHPN1-AS1 may be a potential therapeutic target in ovarian cancer.

LncRNA TONSL-AS1 regulates miR-490-3p/CDK1 to affect ovarian epithelial carcinoma cell proliferation

Background

LncRNA TONSL-AS1 has been characterized as a critical player in gastric cancer. By analyze the TCGA dataset, we observed the upregulation of TONSL-AS1 in ovarian epithelial carcinoma (EOC). We therefore investigated the involvement of TONSL-AS1 in EOC.

Methods

The differential expression of TONSL-AS1 in EOC was first explored by analyzing the TCGA dataset. The effects of overexpression of TONSL-AS1 and miR-490-3p on the expression of CDK1 mRNA and protein in OVCAR3 cells were evaluated by qPCR and western blot, respectively. CCK-8 assay was performed to investigate the effects of overexpression of TONSL-AS1, miR-490-3p and CDK1 on proliferation of OVCAR3 cells.

Results

We observed that TONSL-AS1 was upregulated in EOC tumor tissues from EOC patients, and its high expression level was correlated with poor survival. Dual luciferase assay and RNA interaction prediction showed the direct interaction between TONSL-AS1 and miR-490-3p. However, overexpression of miR-490-3p did not affect the expression of TONSL-AS1. Instead, overexpression of TONSL-AS1 resulted in the upregulation of CDK1, a target of miR-490-3p, in EOC cells. Overexpression of TONSL-AS1 and CDK1 resulted in increased proliferation rate of EOC cells. Overexpression of miR-490-3p played an opposite role and reduced the effects of overexpression of TONSL -AS1 and CDK1.

Conclusions

Therefore, TONSL-AS1 may regulate miR-490-3p/CDK1 to affect EOC cell proliferation.

Colon Cancer-Associated Transcripts 1 and 2: Roles and functions in human cancers

The long noncoding RNAs (lncRNAs) Colon Cancer-Associated Transcripts 1 and 2 (CCAT1 and CCAT2) are located in a recurrently amplified region in cancers. Their proximity with the Myc oncogene and their interactions with its promoter provided further evidence for their contribution in the tumorigenesis processes. Several cell line and clinical studies have shown upregulation of these lncRNAs in diverse malignancies. Moreover, some single nucleotide variants within these genes have been associated with cancer risk or therapeutic response in different populations. Besides, these two lncRNAs act as sponges for some tumor suppressor microRNAs (miRNAs), thus promoting cancer evolution. In the current study, we review recent literature about their expression level, interaction with cancer-related pathways, their role in determination of cell fate and their contribution in malignant phenotype characteristics. Taken together, the current literature shows that these lncRNAs are putative targets for design of novel treatment strategies. Moreover, their expression levels in biopsied samples, exosomes, and sera of patients might be applied as diagnostic biomarkers or markers for patient follow-up.