Long noncoding RNA MEG3 is downregulated in cervical cancer and affects cell proliferation and apoptosis by regulating miR-21

microRNA 21 and long non-coding RNAs interplays underlie cancer pathophysiology: A narrative review

Non-coding RNAs (ncRNAs) are a diverse group of functional RNA molecules that lack the ability to code for proteins. Despite missing this traditional role, ncRNAs have emerged as crucial regulators of various biological processes and have been implicated in the development and progression of many diseases, including cancer. MicroRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are two prominent classes of ncRNAs that have emerged as key players in cancer pathophysiology. In particular, miR-21 has been reported to exhibit oncogenic roles in various forms of human cancer, including prostate, breast, lung, and colorectal cancer. In this context, miR-21 overexpression is closely associated with tumor proliferation, growth, invasion, angiogenesis, and chemoresistance, whereas miR-21 inactivation is linked to the regression of most tumor-related processes. Accordingly, miR-21 is a crucial modulator of various canonical oncogenic pathways such as PTEN/PI3K/Akt, Wnt/β-catenin, STAT, p53, MMP2, and MMP9. Moreover, interplays between lncRNA and miRNA further complicate the regulatory mechanisms underlying tumor development and progression. In this regard, several lncRNAs have been found to interact with miR-21 and, by functioning as competitive endogenous RNAs (ceRNAs) or miRNA sponges, can modulate cancer tumorigenesis. This work presents and discusses recent findings highlighting the roles and pathophysiological implications of the miR-21-lncRNA regulatory axis in cancer occurrence, development, and progression. The data collected indicate that specific lncRNAs, such as MEG3, CASC2, and GAS5, are strongly associated with miR-21 in various types of cancer, including gastric, cervical, lung, and glioma. Indeed, these lncRNAs are well-known tumor suppressors and are commonly downregulated in different types of tumors. Conversely, by modulating various mechanisms and oncogenic signaling pathways, their overexpression has been linked with preventing tumor formation and development. This review highlights the significance of these regulatory pathways in cancer and their potential for use in cancer therapy as diagnostic and prognostic markers.

RhoGDIβ inhibition via miR-200c/AUF1/SOX2/miR-137 axis contributed to lncRNA MEG3 downregulation-mediated malignant transformation of human bronchial epithelial cells

Nickel pollution is a recognized factor contributing to lung cancer. Understanding the molecular mechanisms of its carcinogenic effects is crucial for lung cancer prevention and treatment. Our previous research identified the downregulation of a long noncoding RNA, maternally expressed gene 3 (MEG3), as a key factor in transforming human bronchial epithelial cells (HBECs) into malignant cells following nickel exposure. In our study, we found that deletion of MEG3 also reduced the expression of RhoGDIβ. Notably, artificially increasing RhoGDIβ levels counteracted the malignant transformation caused by MEG3 deletion in HBECs. This indicates that the reduction in RhoGDIβ contributes to the transformation of HBECs due to MEG3 deletion. Further exploration revealed that MEG3 downregulation led to enhanced c-Jun activity, which in turn promoted miR-200c transcription. High levels of miR-200c subsequently increased the translation of AUF1 protein, stabilizing SOX2 messenger RNA (mRNA). This stabilization affected the regulation of miR-137, SP-1 protein translation, and the suppression of RhoGDIβ mRNA transcription and protein expression, leading to cell transformation. Our study underscores the co-regulation of RhoGDIβ expression by long noncoding RNA MEG3, multiple microRNAs (miR-200c and miR-137), and RNA-regulated transcription factors (c-Jun, SOX2, and SP1). This intricate network of molecular events sheds light on the nature of lung tumorigenesis. These novel findings pave the way for developing targeted strategies for the prevention and treatment of human lung cancer based on the MEG3/RhoGDIβ pathway.

Harnessing the supremacy of MEG3 LncRNA to defeat gastrointestinal malignancies

Evidence suggests that long non-coding RNAs (lncRNAs) play a pivotal role in the carcinogenesis and progression of various human malignancies including gastrointestinal malignancies. This comprehensive review reports the functions and mechanisms of the lncRNA maternally expressed gene 3 (MEG3) involved in gastrointestinal malignancies. It summarizes its roles in mediating the regulation of cellular proliferation, apoptosis, migration, invasiveness, epithelial-to-mesenchymal transition, and drug resistance in several gastrointestinal cancers such as colorectal cancer, gall bladder cancer, pancreatic cancer, gastric cancer, esophageal cancer, cholangiocarcinoma, gastrointestinal stromal tumors and most importantly, hepatocellular carcinoma. In addition, the authors briefly highlight its implicated mechanistic role and interactions with different non-coding RNAs and oncogenic signaling cascades. This review presents the rationale for developing non coding RNA-based anticancer therapy via harnessing the power of MEG3 in gastrointestinal malignancies.

LncRNAs: the art of being influential without protein

The plant long noncoding (lnc)RNA field is on the brink of transitioning from large-scale identification of lncRNAs to their functional characterization. Due to the cross-kingdom conservation of interaction types and molecular functions, there is much to be learned from mammalian lncRNA research. Here, we discuss the different molecular processes involving lncRNAs from the regulation of chromatin to splicing. Furthermore, we discuss the lncRNA interactome, which includes proteins, other RNAs, and DNA. We explore and discuss how mammalian lncRNA functionalities could be reflected in similar pathways in plants and hypothesize that several breakthroughs in mammalian research could lead to the discovery of novel plant lncRNA molecular functions. Expanding our knowledge of the biological role of lncRNAs and their multiple applications paves the way for future agricultural applications.

From diagnosis to therapy: The transformative role of lncRNAs in eye cancer management

The genomic era has brought about a transformative shift in our comprehension of cancer, unveiling the intricate molecular landscape underlying disease development. Eye cancers (ECs), encompassing diverse malignancies affecting ocular tissues, pose distinctive challenges in diagnosis and management. Long non-coding RNAs (lncRNAs), an emerging category of non-coding RNAs, are pivotal actors in the genomic intricacies of eye cancers. LncRNAs have garnered recognition for their multifaceted roles in gene expression regulation and influence on many cellular processes. Many studies support that the lncRNAs have a role in developing various cancers. Recent investigations have pinpointed specific lncRNAs associated with ECs, including retinoblastoma and uveal melanoma. These lncRNAs exert control over critical pathways governing tumor initiation, progression, and metastasis, endowing them with the ability to function as evaluation, predictive, and therapeutic indicators. The article aims to synthesize the existing information concerning the functions of lncRNAs in ECs, elucidating their regulatory mechanisms and clinical significance. By delving into the lncRNAs' expanding relevance in the modulation of oncogenic and tumor-suppressive networks, we gain a deeper understanding of the molecular complexities intrinsic to these diseases. In our exploration of the genomic intricacies of ECs, lncRNAs introduce a fresh perspective, providing an opportunity to function as clinical and therapeutic indicators, and they also have therapeutic benefits that show promise for advancing the treatment of ECs. This comprehensive review bridges the intricate relationship between lncRNAs and ECs within the context of the genomic era.

Bioinformatics analysis proposes a possible role for long noncoding RNA MIR17HG in retinoblastoma

BACKGROUND

Retinoblastoma (RB) is the most common prevalent intraocular malignancy among infants and children, particularly in underdeveloped countries. With advancements in genomics and transcriptomics, noncoding RNAs have been increasingly utilized to investigate the molecular pathology of diverse diseases.

AIMS

This study aims to establish the competing endogenous RNAs network associated with RB, analyse the function of mRNAs and lncRNAs, and finds the relevant regulatory network.

METHODS AND RESULTS

This study establishes a network of competing endogenous RNAs by Spearman correlation analysis and prediction based on RB patients and healthy children. Enrichment analyzes based on Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes are conducted to analyze the potential biological functions of lncRNA and mRNA networks. Weighted gene co-expression network analysis (WGCNA) is employed to identify gene cluster modules exhibiting the strongest correlation with RB. The results indicate a significant correlation between the lncRNA MIR17HG (R = .73, p = .02) and the RB phenotype. ceRNA networks reveal downstream miRNAs (hsa-mir-425-5p and hsa-mir455-5p) and mRNAs (MDM2, IPO11, and ITGA1) associated with MIR17Hg. As an inhibitor of the p53 signaling pathway, MDM2 can suppress the development of RB.

CONCLUSION

In conclusion, lncRNAs play a role in RB, and the MIR17HG/hsa-mir-425-5p/MDM2 pathway may contribute to RB development by inhibiting the p53 signaling pathway.

The ceRNA Mechanism of lncRNA MEG3/miR-21-5p/SPRY2 in Cell Proliferation and Apoptosis in Bladder Cancer

Bladder cancer (BC) is the second most common genitourinary malignancy. Long noncoding RNA (lncRNA) is implicated in BC progression. This study delved into the underlying mechanism of lncRNA MEG3 in BC. Bioinformatics analysis predicted the expression of lncRNA MEG3, its association with the survival of BC patients, its subcellular localization, and its binding sites with miR-21-5p. Differentially expressed genes (DEGs) in the GSE13507 chip were analyzed using GEOexplorer, downstream targets of miR-21-5p were predicted from databases, and the overlapping genes were analyzed by the website Venny2.1 (https://bioinfogp.cnb.csic.es/tools/venny/index.html); their impacts on patient survival were analyzed by the Starbase database. The expression of SPRY2 and TGFBI associated with patient survival was analyzed in TCGA. RT-qPCR and western blot were performed to detect levels of MEG3, miR-21-5p, and SPRY2 in BC/SV-HUC-1 cells. Malignant biological behaviors of BC cells were detected using CCK8, flow cytometry, and Transwell assays. RNA pull-down and dual-luciferase assays were employed to verify the binding relationship of miR-21-5p with MEG3 and SPRY2. MEG3 was found to be lowly expressed in BC cells and mainly distributed in the cytoplasm. Over-expression of MEG3 was found to inhibit BC cell activity, promote apoptosis, and reduce invasion and migration. miR-21-5p was found to be highly expressed in BC cells, and its down-regulation was found to inhibit the malignant behavior of BC cells. Over-expression of miR-21-5p was found to reverse the effect of pcDNA3.1-MEG3 on BC cells. MEG3 was found to competitively bind to miR-21-5p as a ceRNA to promote SPRY2 levels. LncRNA MEG3 promotes SPRY2 expression by competitively binding to miR-21-5p, thereby inhibiting proliferation and promoting apoptosis of BC cells.

Apoptosis and long non-coding RNAs: Focus on their roles in Heart diseases

Heart disease is one of the principal death reasons around the world and there is a growing requirement to discover novel healing targets that have the potential to avert or manage these illnesses. On the other hand, apoptosis is a strongly controlled, cell removal procedure that has a crucial part in numerous cardiac problems, such as reperfusion injury, MI (myocardial infarction), consecutive heart failure, and inflammation of myocardium. Completely comprehending the managing procedures of cell death signaling is critical as it is the primary factor that influences patient mortality and morbidity, owing to cardiomyocyte damage. Indeed, the prevention of heart cell death appears to be a viable treatment approach for heart illnesses. According to current researches, a number of long non-coding RNAs cause the heart cells death via different methods that are embroiled in controlling the activity of transcription elements, the pathways that signals transmission within cells, small miRNAs, and the constancy of proteins. When there is too much cell death in the heart, it can cause problems like reduced blood flow, heart damage after restoring blood flow, heart disease in diabetics, and changes in the heart after reduced blood flow. Therefore, studying how lncRNAs control apoptosis could help us find new treatments for heart diseases. In this review, we present recent discoveries about how lncRNAs are involved in causing cell death in different cardiovascular diseases.

The complex role of MEG3: An emerging long non-coding RNA in breast cancer

MEG3, a significant long non-coding RNA (lncRNA), substantially functions in diverse biological processes, particularly breast cancer (BC) development. Within the imprinting DLK-MEG3 region on human chromosomal region 14q32.3, MEG3 spans 35 kb and encompasses ten exons. It exerts regulatory effects through intricate interactions with miRNAs, proteins, and epigenetic modifications. MEG3's multifaceted function in BC is evident in gene expression modulation, osteogenic tissue differentiation, and involvement in bone-related conditions. Its role as a tumor suppressor is highlighted by its influence on miR-182 and miRNA-29 expression in BC. Additionally, MEG3 is implicated in acute myocardial infarction and endothelial cell function, emphasising cell-specific regulatory mechanisms. MEG3's impact on gene activity encompasses transcriptional and post-translational adjustments, including DNA methylation, histone modifications, and interactions with transcription factors. MEG3 dysregulation is linked to unfavourable outcomes and drug resistance. Notably, higher MEG3 expression is associated with enhanced survival in BC patients. Overcoming challenges such as unravelling context-specific interactions, understanding epigenetic control, and translating findings into clinical applications is imperative. Prospective endeavours involve elucidating underlying mechanisms, exploring epigenetic alterations, and advancing MEG3-based diagnostic and therapeutic approaches. A comprehensive investigation into broader signaling networks and rigorous clinical trials are pivotal. Rigorous validation through functional and molecular analyses will shed light on MEG3's intricate contribution to BC progression.

MicroRNA-21 in gynecological cancers: From molecular pathogenesis to clinical significance

Ovarian, cervical, and endometrial cancers are the three most common gynecological cancer types (GCs). They hold a significant position as the leading causes of mortality among women with cancer-related death. However, GCs are often diagnosed late, severely limiting the efficacy of current treatment options. Thus, there is an urgent, unmet need for innovative experimentation to enhance the clinical treatment of GC patients. MicroRNAs (miRNAs) are a large and varied class of short noncoding RNAs (22 nucleotides in length) that have been shown to play essential roles in various biological processes involved in development. Recent research has shown that miR-211 influences tumorigenesis and cancer formation, adding to our knowledge of the miR-21 dysregulation in GCs. Furthermore, current research that sheds light on the crucial functions of miR-21 may provide supporting evidence for its potential prognostic, diagnostic, and therapeutic applications in the context of GCs. This review will thus focus on the most recent findings concerning miR-21 expression, miR-21 target genes, and the processes behind GCs. In addition, the latest findings that support miR-21's potential use as a non-invasive biomarker and therapeutic agent for detecting and treating cancer will be elucidated in this review. The roles played by various lncRNA/circRNA-miRNA-mRNA axis in GCs are also comprehensively summarized and described in this study, along with any possible implications for how these regulatory networks may contribute to the pathogenesis of GCs. Also, it is crucial to recognize the complexity of the processes involved in tumour therapeutic resistance as a significant obstacle in treating GCs. Furthermore, this review provides an overview of the current state of knowledge regarding the functional significance miR-21 in therapeutic resistance within the context of GCs.

Extracellular vesicles: a rising star for therapeutics and drug delivery

Extracellular vesicles (EVs) are nano-sized, natural, cell-derived vesicles that contain the same nucleic acids, proteins, and lipids as their source cells. Thus, they can serve as natural carriers for therapeutic agents and drugs, and have many advantages over conventional nanocarriers, including their low immunogenicity, good biocompatibility, natural blood-brain barrier penetration, and capacity for gene delivery. This review first introduces the classification of EVs and then discusses several currently popular methods for isolating and purifying EVs, EVs-mediated drug delivery, and the functionalization of EVs as carriers. Thereby, it provides new avenues for the development of EVs-based therapeutic strategies in different fields of medicine. Finally, it highlights some challenges and future perspectives with regard to the clinical application of EVs.

HNRNPA2B1-mediated m6A modification of lncRNA MEG3 facilitates tumorigenesis and metastasis of non-small cell lung cancer by regulating miR-21-5p/PTEN axis

BACKGROUND

Accumulating data indicate that N6-methyladenosine (m⁶A) RNA methylation and lncRNA deregulation act crucial roles in cancer progression. Heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1) as an m⁶A "reader" has been reported to be an oncogene in multiple malignancies. We herein aimed to elucidate the role and underlying mechanism by which HNRNPA2B1-mediated m⁶A modification of lncRNAs contributes to non-small cell lung cancer (NSCLC).

METHODS

The expression levels of HNRNPA2B1 and their association with the clinicopathological characteristics and prognosis in NSCLC were determined by RT-qPCR, Western blot, immunohistochemistry and TCGA dataset. Then, the role of HNRNPA2B1 in NSCLC cells was assessed by in vitro functional experiments and in vivo tumorigenesis and lung metastasis models. HNRNPA2B1-mediated m⁶A modification of lncRNAs was screened by m⁶A-lncRNA epi-transcriptomic microarray and verified by methylated RNA immunoprecipitation (Me-RIP). The lncRNA MEG3-specific binding with miR-21-5p was evaluated by luciferase gene report and RIP assays. The effects of HNRNPA2B1 and (or) lncRNA MEG3 on miR-21-5p/PTEN/PI3K/AKT signaling were examined by RT-qPCR and Western blot analyses.

RESULTS

We found that upregulation of HNRNPA2B1 was associated with distant metastasis and poor survival, representing an independent prognostic factor in patients with NSCLC. Knockdown of HNRNPA2B1 impaired cell proliferation and metastasis in vitro and in vivo, whereas ectopic expression of HNRNPA2B1 possessed the opposite effects. Mechanical investigations revealed that lncRNA MEG3 was an m⁶A target of HNRNPA2B1 and inhibition of HNRNPA2B1 decreased MEG3 m⁶A levels but increased its mRNA levels. Furthermore, lncRNA MEG3 could act as a sponge of miR-21-5p to upregulate PTEN and inactivate PI3K/AKT signaling, leading to the suppression of cell proliferation and invasion. Low expression of lncRNA MEG3 or elevated expression of miR-21-5p indicated poor survival in patients with NSCLC.

CONCLUSIONS

Our findings uncover that HNRNPA2B1-mediated m⁶A modification of lncRNA MEG3 promotes tumorigenesis and metastasis of NSCLC cells by regulating miR-21-5p/PTEN axis and may provide a therapeutic target for NSCLC.

Long non-coding RNAs as promising biomarkers and therapeutic targets in cervical cancer

Cervical cancer is the second most common cancer in women. The detection of oncopathologies in the early stages of development is a paramount task of modern medicine, which can be solved only by improving modern diagnostic methods. The use of screening for certain tumor markers could complement modern tests such as testing for oncogenic types of human papillomavirus (HPV), cytology, colposcopy with acetic acid and iodine solutions. Such highly informative biomarkers can be long noncoding RNAs (lncRNAs) that are highly specific compared to the mRNA profile and are involved in the regulation of gene expression. LncRNAs are a class of non-coding RNAs molecules that are typically over 200 nucleotides in length. LncRNAs may be involved in the regulation of all major cellular processes, including proliferation and differentiation, metabolism, signaling pathways, and apoptosis. LncRNAs molecules are highly stable due to their small size, which is also their undoubted advantage. The study of individual lncRNAs as regulators of the expression of genes involved in the mechanisms of oncogenesis cervical cancer can be not only of great diagnostic value, but, as a result, of therapeutic significance in cervical cancer patients. This review article will present the characteristics of lncRNAs that allow them to be used as accurate diagnostic and prognostic tools, as well as to consider them as effective therapeutic targets in cervical cancer.

Overview of genetic and epigenetic regulation of human papillomavirus and apoptosis in cervical cancer

Cervical cancer is the fourth most common cancer affecting women worldwide after breast, colorectal and lung cancers. Owing to a lack of awareness and resources, low- and middle-income countries bear most of the burden of cervical cancer. In developed countries, the incidence rate has been halved over the past three decades due to robust screening and implementation of vaccine programs. HPV is not the sole cause of cervical cancer but acts as a principal factor in the pathogenesis of cervical cancer. By integrating into the host genome, its oncogenic proteins (E6 and E7) alter and interfere with the standard signal transduction machinery of the host. Apoptosis is a key pathway affected by aberrant genetic mutations, polymorphisms and epigenetic mechanisms during cervical carcinogenesis. Along with DNA methylation and histone modifications, non-coding RNAs have also been implicated as epigenetic modulators in various malignancies and are being explored for reversing disease severity. This review emphasizes various genetic and epigenetic approaches regulating apoptotic pathways and HPV E6 and E7 genes that can be targeted to overcome the challenges in cervical cancer treatment. In addition, it also discusses the apoptosis targeting novel drug molecules in cervical cancer which are currently undergoing clinical and pre-clinical trials.

A systematic review and meta-analysis of miRNAs for the detection of cervical cancer

Aim: This study aimed to critically appraise the evidence of the diagnostic effectiveness of miRNAs for the detection of cervical cancer. Methods & materials: A systematic review and meta-analysis was performed, searching PubMed, EMBASE and Web of Science. An umbrella meta-analysis of meta-analyses of individual biomarkers was performed. A Grading of Recommendations, Assessment, Development and Evaluations (GRADE) assessment of evidence was also performed. Results: A total of 52 miRNAs were included. Umbrella meta-analysis revealed significant heterogeneity in terms of sensitivity, specificity, receiver operating characteristic (ROC), positive predictive value and/or negative predictive value. Umbrella effects were 0.76 (95% CI: 0.73-0.78), 0.78 (95% CI: 0.75-0.81), 0.77 (95% CI: 0.75-0.80), 0.75 (95% CI: 0.71-0.79) and 0.76 (95% CI: 0.74-0.79), respectively. Conclusion: Moderate quality evidence suggested miR199a-5p, miR21-5p and miR-141a had excellent diagnostic performance.

Long non-coding RNAs as critical regulators and novel targets in cervical cancer: current status and future perspectives

Cervical cancer is among the leading causes of cancer-associated mortality in women. In spite of vaccine availability, improved screening procedures, and chemoradiation therapy, cervical cancer remains the most commonly diagnosed cancer in 23 countries and the leading cause of cancer deaths in 36 countries. There is, therefore, a need to come up with novel diagnostic and therapeutic targets. Long non-coding RNAs (lncRNAs) play a remarkable role in genome regulation and contribute significantly to several developmental and disease pathways. The deregulation of lncRNAs is often observed in cancer patients, where they are shown to affect multiple cellular processes, including cell cycle, apoptosis, angiogenesis, and invasion. Many lncRNAs are found to be involved in the pathogenesis as well as progression of cervical cancer and have shown potency to track metastatic events. This review provides an overview of lncRNA mediated regulation of cervical carcinogenesis and highlights their potential as diagnostic and prognostic biomarkers as well as therapeutic targets for cervical cancer. In addition, it also discusses the challenges associated with the clinical implication of lncRNAs in cervical cancer.

Nanoconjugated long non-coding RNA MEG3 as a new therapeutic approach for Hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is an aggressive human cancer with a poor prognosis. Long non-coding RNAs (lncRNA) have multiple functions: epigenomic regulation, gene transcription, protein-coding gene translation, and genome defense. The involvement of lncRNAs in therapy offers a vast step in cancer treatment.

Objective

In the current study, a novel therapeutic regimen using polymer nanoparticle-mediated delivery of lncRNA was designed to control the progression of hepatocarcinogenesis.

Methods

One hundred mice were divided into 5 groups. The first group served as a normal-control group and was injected with saline, whereas the pathological-control group (the second group) was injected with N-Nitrosodiethylamine (DEN) weekly for 16 weeks. Group 3, Group 4, and Group 5 were injected intrahepatically with polymer nanoparticles (NPs) alone, lncRNA MEG3 alone, and conjugated NPs, respectively, once/week for four weeks starting on the 12th week after DEN injection. After 16 weeks, animals were euthanized, and liver specimens and blood samples were collected for pathological, molecular, and biochemical assessment.

Results

Compared to the pathological-control group, nanoconjugates lncRNA MEG3 demonstrated a significant improvement in histopathology and tumour-associated biomarkers. Furthermore, the expression of the SENP1 and PCNA was downregulated.

Conclusion

MEG3 conjugated nanoparticles can be considered a novel therapeutic regimen for HCC.

A Comprehensive View of the Cancer-Immunity Cycle (CIC) in HPV-Mediated Cervical Cancer and Prospects for Emerging Therapeutic Opportunities

Cervical cancer (CC) is the fourth most common cancer in women worldwide, with more than 500,000 new cases each year and a mortality rate of around 55%. Over 80% of these deaths occur in developing countries. The most important risk factor for CC is persistent infection by a sexually transmitted virus, the human papillomavirus (HPV). Conventional treatments to eradicate this type of cancer are accompanied by high rates of resistance and a large number of side effects. Hence, it is crucial to devise novel effective therapeutic strategies. In recent years, an increasing number of studies have aimed to develop immunotherapeutic methods for treating cancer. However, these strategies have not proven to be effective enough to combat CC. This means there is a need to investigate immune molecular targets. An adaptive immune response against cancer has been described in seven key stages or steps defined as the cancer-immunity cycle (CIC). The CIC begins with the release of antigens by tumor cells and ends with their destruction by cytotoxic T-cells. In this paper, we discuss several molecular alterations found in each stage of the CIC of CC. In addition, we analyze the evidence discovered, the molecular mechanisms and their relationship with variables such as histological subtype and HPV infection, as well as their potential impact for adopting novel immunotherapeutic approaches.

Role of noncoding RNAs with emphasis on long noncoding RNAs as cervical cancer biomarkers

Cervical cancer is a significant public health problem in developing countries, as most cases present at an advanced stage. This review aimed to analyze the role of noncoding RNAs as diagnostic and prognostic biomarkers in cervical cancers. Published studies on specific microRNA signatures in body fluids and cervical cancer tissues are highly heterogeneous, and there are no validated assays. The precision of the various immune-associated long noncoding (lncRNA) signatures should be assessed in clinical samples. Even though lncRNAs are tissue and cancer-specific, safe and appropriate methods for delivery to tumor tissues, toxicities and side effects are to be explored. Few studies have evaluated deregulated lncRNA expression levels with clinicopathological factors in a limited number of clinical samples. Prospective studies assessing the diagnostic and prognostic roles of circulating lncRNAs and P-Element-induced wimpy testis interacting PIWI RNAs (Piwil RNAs) in cervical cancer cases are essential. For the clinical application of lnc-RNA-based biomarkers, comprehensive research is needed as the impact of noncoding transcripts on molecular pathways is complex. The standardization and validation of deregulated ncRNAs in noninvasive samples of cervical cancer cases are needed.

Pre-clinical and clinical importance of miR-21 in human cancers: Tumorigenesis, therapy response, delivery approaches and targeting agents

The field of non-coding RNA (ncRNA) has made significant progress in understanding the pathogenesis of diseases and has broadened our knowledge towards their targeting, especially in cancer therapy. ncRNAs are a large family of RNAs with microRNAs (miRNAs) being one kind of endogenous RNA which lack encoded proteins. By now, miRNAs have been well-coined in pathogenesis and development of cancer. The current review focuses on the role of miR-21 in cancers and its association with tumor progression. miR-21 has both oncogenic and onco-suppressor functions and most of the experiments are in agreement with the tumor-promoting function of this miRNA. miR-21 primarily decreases PTEN expression to induce PI3K/Akt signaling in cancer progression. Overexpression of miR-21 inhibits apoptosis and is vital for inducing pro-survival autophagy. miR-21 is vital for metabolic reprogramming and can induce glycolysis to enhance tumor progression. miR-21 stimulates EMT mechanisms and increases expression of MMP-2 and MMP-9 thereby elevating tumor metastasis. miR-21 is a target of anti-cancer agents such as curcumin and curcumol and its down-regulation impairs tumor progression. Upregulation of miR-21 results in cancer resistance to chemotherapy and radiotherapy. Increasing evidence has revealed the role of miR-21 as a biomarker as it is present in both the serum and exosomes making them beneficial biomarkers for non-invasive diagnosis of cancer.

The interplay of long noncoding RNAs and hepatitis B virus

Hepatitis B Virus (HBV) infections remain a major global health burden with an estimated 296 million people living with a chronic infection and 884,000 HBV-related deaths annually. Notably, patients with a chronic hepatitis B (CHB) infection are at a 30-fold greater risk of developing hepatocellular carcinoma (HCC), the most common type of primary liver cancer, which is the 3rd deadliest cancer worldwide. Several groups have assessed HBV-related aberrant expression of host-cell long noncoding RNAs (lncRNAs) and how altered expression of specific lncRNAs affects HBV replication and progression to associated disease states. Given the challenges in establishing effective HBV models and analyzing transcriptomic data, this review focuses on lncRNA expression data primarily collected from clinical patient samples and primary human hepatocytes, with the subsequent mechanism of action analysis in cell lines or other model systems. Ultimately, understanding HBV-induced lncRNA-expression dysregulation could lead to new treatments and biomarkers for HBV infection and its associated diseases.

The Biological Roles and Molecular Mechanisms of Long Non-Coding RNA MEG3 in the Hallmarks of Cancer

Long non-coding RNAs (lncRNAs) are critical regulators in various biological processes involved in the hallmarks of cancer. Maternally expressed gene 3 (MEG3) is lncRNA that regulates target genes through transcription, translation, post-translational modification, and epigenetic regulation. MEG3 has been known as a tumor suppressor, and its downregulation could be found in various cancers. Furthermore, clinical studies revealed that impaired MEG3 expression is associated with poor prognosis and drug resistance. MEG3 exerts its tumor suppressive effect by suppressing various cancer hallmarks and preventing cells from acquiring cancer-specific characteristics; as it could suppress tumor cells proliferation, invasion, metastasis, and angiogenesis; it also could promote tumor cell death and regulate tumor cell metabolic reprogramming. Hence, MEG3 is a potential prognostic marker, and overexpressing MEG3 might become a potential antitumor therapeutic strategy. Herein, we summarize recent knowledge regarding the role of MEG3 in regulating tumor hallmarks as well as the underlying molecular mechanisms. Furthermore, we also discuss the clinical importance of MEG3, as well as their potential in tumor prognosis and antitumor therapeutic strategies.

A review of current evidence about lncRNA MEG3: A tumor suppressor in multiple cancers

Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) is a lncRNA located at the DLK1-MEG3 site of human chromosome 14q32.3. The expression of MEG3 in various tumors is substantially lower than that in normal adjacent tissues, and deletion of MEG3 expression is involved in the occurrence of many tumors. The high expression of MEG3 could inhibit the occurrence and development of tumors through several mechanisms, which has become a research hotspot in recent years. As a member of tumor suppressor lncRNAs, MEG3 is expected to be a new target for tumor diagnosis and treatment. This review discusses the molecular mechanisms of MEG3 in different tumors and future challenges for the diagnosis and treatment of cancers through MEG3.

Possible Role of lncRNA MEG3-microRNA-21 and Endoplasmic Reticulum (ER) Stress Proteins in the Pathogenesis of Psoriasis Vulgaris

BACKGROUND

Psoriasis is a chronic inflammatory immune mediated disease arising from interaction between genetic risk variants and the environment. Maternally expressed gene3 (MEG3) is a long noncoding RNA (lncRNA) known for gene transcription regulation and inhibiting proliferation. MEG3 competes with microRNA (miRNA-21) influencing cell proliferation and apoptosis balance. Endoplasmic reticulum (ER) stress proteins promote cell survival via unfolded protein response (UPR) influenced by MEG3. We aimed to detect the possible role of MEG3, miRNA-21 and ER stress proteins in pathogenesis of psoriasis vulgaris.

METHODS

Human GRP78, ATF6, caspase3 tissue levels were assayed by Enzyme Linked Immunosorbent Assay (ELISA). Assessment of long non-coding MEG3 and miRNA 21 expressions was done by quantitative real time polymerase chain reaction (qRT-PCR).

RESULTS

Expression of MEG3 was significantly downregulated, while miRNA-21 was remarkably upregulated, ER stress proteins GRP78, ATF6, and caspase 3 all showed low levels in homogenized psoriatic lesions when compared to normal skin. miRNA 21 and MEG3 were identified as possible diagnostic markers for psoriasis vulgaris.

DISCUSSION

MEG3 is barely expressed in psoriatic lesions while miRNA-21 expression is remarkably elevated but when correlated to each other there was unexpected positive correlation. MEG3 and miRNA-21 were identified as possible diagnostic markers for psoriasis. Undifferentiated psoriatic lesions have very weak UPR.

Integrated Analysis of the lncRNA-Associated ceRNA Network in Wilms Tumor via TARGET and GEO Databases

Wilms tumor (WT) is the most common genitourinary renal tumor that typically occurs in children under 15 and is thought to be linked to somatic and germline mutations. However, the specific functional role of competing endogenous RNAs (ceRNAs) and their potential implications in WT remain unclear. In this study, we developed an lncRNA-mediated (long noncoding RNA-mediated) ceRNA network via the R packages for WT with expression data obtained from the tumor alterations relevant for genomics-driven therapy (TARGET) database. Unsupervised hierarchical clustering analysis revealed that the WT specimens could be clearly distinguished from healthy specimens with respect to the expression of disordered RNAs. A total of 1,607 differentially expressed (DE) lncRNAs, 116 DE microRNAs (DEmiRNAs), and 3,262 DE messenger RNAs (DEmRNAs) were identified as WT-specific RNAs, and a lncRNA-miRNA-mRNA ceRNA network with 159 DElncRNAs, 18 DEmiRNAs, 131 DEmRNAs, and 792 interactions was constructed. According to the clinical survival data, 12 DElncRNAs, 5 DEmRNAs, and 2 DEmiRNAs were selected from the ceRNA network that could significantly impact the overall survival of WT patients (P < 0.05). Functional enrichment analysis showed that the biological processes and pathways of DEmRNAs, such as cell cycle and virus infection, may be associated with WT. The present study constructed a dysregulated lncRNA-mediated ceRNA network in WT and discovered that lncRNA-mediated ceRNAs may serve as important regulators in WT development and progression. Survival-associated RNAs may serve as new potential biomarkers, suggesting that the constructed ceRNA network in WT might be important for determining optimal therapeutic strategies.

Long Non-coding RNAs: Pivotal Epigenetic Regulators in Diabetic Retinopathy

Diabetic retinopathy (DR) is a severe complication of diabetes; however, its mechanism is not fully understood. Evidence has recently revealed that long non-coding RNAs (lncRNAs) are abnormally expressed in DR, and lncRNAs may function as pivotal regulators. LncRNAs are able to modulate gene expression at the epigenetic level by acting as scaffolds of histone modification complexes and sponges of binding with microRNAs (miRNAs). LncRNAs are believed to be important epigenetic regulators, which may become beneficial in the diagnosis and therapy of DR. However, the mechanisms of lncRNAs in DR are still unclear. In this review, we summarize the possible functions and mechanisms of lncRNAs in epigenetic regulation to target genes in the progression of DR.

The IncRNA SCIRT Promotes the Proliferative, Migratory, and Invasive Properties of Cervical Cancer Cells by Upregulating MMP-2/-9

Objective. The morbidity and mortality of cervical cancer (CC) rank the fourth-most common among cancers in females, seriously threatening women’s health and affecting their quality of life. However, the molecular mechanism of CC development remains poorly understood. This study investigates the role of lncRNA SCIRT in the development of CC. Methods. The expression profile of long noncoding RNA stem cell inhibitory RNA transcript (lncRNA SCIRT) in CC (n = 34), tumor-adjacent tissue, and CC cell culture was determined through fluorescence quantitative PCR. The knockdown /overexpressed lncRNA SCIRT vectors were constructed and transfected into cells, and the effects of knockdown or overexpression of lncRNA SCIRT on the proliferative, invasive, and migratory properties of CC cells were determined through Cell Counting Kit-8 (CCK-8), colony forming, and Transwell experiments. Western blot was employed to determine the knockdown/overexpression efficiency of SCIRT and its role on the expression of proteins (e-cadherin, n-cadherin, vimentin, matrix metalloproteinase (MMP)-9 and MMP-2) in CC cells. Finally, SCIRT knockdown on the proliferative ability for CC cells was determined through tumorigenic experiment in nude mice. Results. LncRNA SCIRT was highly expressed in CC tissues and cells, and significantly linked with clinical/pathology-based characteristics of patients, including Federation Internationale of Gynecologie and Obstetrigue (FIGO) stage, tumor dimensions, and lymph-node metastasis. SCIRT knockdown markedly reduced CC proliferative, colony forming, and invasive properties, while overexpressing SCIRT promoted the proliferative and invasive properties of CC. Western blotting analysis demonstrated that SCIRT knockdown upregulated e-cadherin and downregulated n-cadherin, vimentin, MMP-9, and MMP-2. Meanwhile, overexpressing SCIRT of lncRNA SCIRT had the opposite effect. Tumorigenic experiment showed that SCIRT knockdown could markedly reduce CC proliferative property the nude mouse. Conclusion. LncRNA SCIRT was highly expressed in CC clinical cases. Knockdown/overexpressing SCIRT affected CC proliferative/invasive properties. Hence, lncRNA SCIRT is a promising drug-target and a new biological diagnostic molecule for CC patients.

DSCAM-AS1 promotes cervical carcinoma cell proliferation and invasion via sponging miR-338-3p

Deregulated lncRNA DSCAM-AS1 expression was found in several tumors. However, mechanism and functional role of DSCAM-AS1 in cervical carcinoma remain unknown. DSCAM-AS1 was detected in cervical carcinoma specimens and cells by RT-qPCR. CCK-8, Matrigel transwell, and flow cytometry were conducted to determine cell functions. In this research, we firstly we explored DSCAM-AS1 expression in cervical carcinoma cells and specimens. We revealed that DSCAM-AS1 was upregulated in cervical carcinoma lines (C4-1, Caski, Hela, and Siha) compared to GH329 cells. DSCAM-AS1 was upregulated in cervical carcinoma specimens compared to control no-tumor specimens. Overexpression of DSCAM-AS1 induced cervical carcinoma cell growth and cycle. Moreover, our data revealed that miR-338-3p expression was downregulated in cervical carcinoma cells and specimens. There was a negative correlation between miR-338-3p expression and DSCAM-AS1 expression in cervical carcinoma specimens. Elevated expression of miR-338-3p decreased cervical carcinoma cell growth and cycle and invasion. Furthermore, luciferase reporter analysis revealed that miR-338-3p overexpression suppressed luciferase activity of WT-DSCAM-AS1 vector but not the mut-DSCAM-AS1. Ectopic expression of DSCAM-AS1 decreased miR-338-3p expression in the Siha cell. Overexpression of DSCAM-AS1 promoted cervical carcinoma cell growth and cycle via regulating miR-338-3p. These results suggested that DSCAM-AS1 functions as one oncogene through sponging miR-338-3p in cervical carcinoma.

Long intergenic noncoding RNA LINC01287 drives the progression of cervical cancer via regulating miR-513a-5p/SERP1

Cervical cancer is one of the most frequent types of cancer in women, which is characterized by high invasion and metastatic tendency in its advanced stage. Emerging evidence indicated that long non-coding RNAs (LncRNAs) are involved in the pathogenesis of cervical cancer. LINC01287 has been reported to play crucial regulatory roles in the pathogenesis and progression of multiple cancers. However, up until now, whether LINC01287 is associated with the initiation and development of cervical cancer remains largely unknown. In the present study, expression levels of LINC01287, miR-513a-5p and stress-associated endoplasmic reticulum protein 1 (SERP1) mRNA were quantified utilizing qRT-PCR. A series of functional experiments including CCK-8 assay, colony formation assay, transwell assay, flow cytometry, and tumor xenograft growth of cervical cancer cells were performed for studying the effects of LINC01287. The luciferase reporter assay, pull-down assay, and western blot were used to confirm the downstream targets of LINC01287 and miR-513a-5p. The results demonstrate that LINC01287 was highly expressed in cervical cancer tissue samples and cell lines. High LINC01287 predicts a poor prognosis for cervical cancer patients. Additional gain- and loss-of-function experiments demonstrated that silencing LINC01287 inhibited cervical cancer cells proliferation, colony formation, migration, apoptosis in vitro and retarded tumor growth and metastasis in vivo. Furthermore, the dual-luciferase reporter gene system and RNA pulldown assay validated that LINC01287 positively regulated SERP1 expressions by sponging miR-513a-5p, and LINC01287 inhibited cervical cancer progression by regulating miR-513a-5p/SERP1 axis. In conclusion, the current study first identified that LINC01287/miR-513a-5p/SERP1 axis played an important role in cervical cancer progression. LINC01287 might be a prognostic biomarker and a target for new therapies in patients with cervical cancer.

Long non-coding RNAs: a valuable biomarker for metabolic syndrome

Long non-coding RNAs (lncRNAs) have become important regulators of gene expression because they affect a wide range of biological processes, such as cell growth, death, differentiation, and aging. More and more evidence suggests that lncRNAs play a role in maintaining metabolic homeostasis. When certain lncRNAs are out of balance, metabolic disorders like diabetes, obesity, and heart disease get worse. In this review, we talk about what we know about how lncRNAs control metabolism, with a focus on diseases caused by long-term inflammation and the characteristics of the metabolic syndrome. We looked at lncRNAs and their molecular targets in the pathogenesis of signaling pathways. We also talked about how lncRNAs are becoming more and more interesting as diagnostic and therapeutic targets for improving metabolic homeostasis.

LncRNA MEG3 inhibits retinoblastoma invasion and metastasis by inducing β-catenin degradation

In our previous study, we found that low expression of LncRNA-MEG3 was closely associated with the invasion and metastasis of retinoblastomas. The molecular mechanism by which MEG3 inactivation induces the invasion and metastasis of retinoblastoma cell lines remains unclear. We used the GEO database to analyze the expression of MEG3 in retinoblastoma tissues and MEG3-related pathways. The scratch, transwell migration, mouse tumor metastasis, and mouse fluorescence live imaging assays were performed to detect migration and invasion of retinoblastoma cell lines. The RNA pull down, electrophoretic mobility shift, RIP, co-immunoprecipitation, and ubiquitination assays were performed to analyze the molecular mechanisms. The GEO database showed that the expression of MEG3 was low in retinoblastoma tissues and was closely associated with the invasion of retinoblastoma cells and activity of the Wnt pathway. Both in vivo and in vitro experiments confirmed that MEG3 inhibited the migration and invasion of retinoblastoma cells. Cell experiments confirmed that MEG3 could promote the binding of β-catenin and GSK-3β and induce phosphorylation, ubiquitination and degradation of β-catenin indirectly. In conclusion, MEG3 can promote the degradation of β-catenin via GSK-3β, which in turn inactivates the Wnt pathway and ultimately inhibits the invasion and metastasis of retinoblastoma cells.

Long non-coding RNAs involved in different steps of cancer metastasis

Non-proteincoding transcripts bearing 200 base pairs known as long non-coding RNAs (lncRNAs) play a role in a variety of molecular mechanisms, including cell differentiation, apoptosis and metastasis. Previous studies have suggested that frequently dysregulated lncRNAs play a crucial role in various aspects of cancer metastasis. Metastasis is the main leading cause of death in cancer. The role of lncRNAs in different stages of metastasis is the subject of this review. Based on in vitro and in vivo investigations on metastasis, we categorized lncRNAs into distinct stages of metastasis including angiogenesis, invasion, intravasation, survival in circulation, and extravasation. The involvement of lncRNAs in angiogenesis and invasion has been extensively studied. Here, we comprehensively discuss the role and functions of these lncRNAs with a particular focus on the molecular mechanisms.

Long non-coding RNA MEG3 promotes tumor necrosis factor-alpha induced oxidative stress and apoptosis in interstitial cells of cajal via targeting the microRNA-21 /I-kappa-B-kinase beta axis

Interstitial Cells of Cajal (ICC) plays a critical role in the peristaltic contractions of the gastrointestinal and urinary tract. The dysfunction and loss of ICC contributes to hypokinetic disease, such as gallstoneand ureteropelvic junction obstruction . In the present study, we identified the underlying driving molecular signals of oxidative stress and apoptosis in ICC. ICC was isolated from small intestine of Balb/c mice, and stimulated with tumor necrosis factor-alpha (TNF-α). MTT and flow cytometry were performed to assess cell viability, apoptosis, and the level of reactive oxygen species in ICC, respectively. The level of malondialdehyde, superoxide dismutase, and glutathione peroxidase in cells were measured to assess oxidative stress. The expression of inflammatory factors (interleukin, IL-1 and IL-6) and apoptosis-related proteins were detected by western blot. We observed that TNF-αinduced inflammation, oxidative stress and cell apoptosis in ICC. By using quantitative real-time PCR , we verified that the expression of long non-coding RNAMEG3 was elevated by TNF-α in ICC. Silencing MEG3 reversed inflammation, oxidative stress, and cell apoptosisin TNF-α-treated ICC. Subsequently, we confirmed that MEG3 sponged cytoprotective miR-21 to upregulate the expression of I-kappa-B-kinase beta (IKKB) and activate the nuclear factor kappa-B (NF-κB) pathway. Both miR-21 overexpression and IKKB knockdown reduced TNF-α-induced above symptoms in ICC. Taken together, we can conclude that MEG3 mediates inflammation, oxidative stress and apoptosis in TNF-α-treated ICC via the miR-21/IKKB-NF-κB axis. The study improves our understanding of the molecular mechanism of ICC reduction related diseases.

Engineered exosome as targeted lncRNA MEG3 delivery vehicles for osteosarcoma therapy

Exosomes as nanosized membrane vesicles, could targeted deliver therapeutic agents by modification with target ligands. Exosome-derived non-coding RNAs play a vital role in the development of tumors. Previous evidences reveal that long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) has anti-tumor properties. Whereas, the inhibitory effects of exosome-derived lncRNA MEG3 in osteosarcoma (OS) remain largely unknown. In this study, we utilize the engineering technology to combine exosome and lncRNA for tumor-targeting therapy of OS. We elucidated the anti-OS effects of lncRNA MEG3, and then prepared the c(RGDyK)-modified and MEG3-loaded exosomes (cRGD-Exo-MEG3). The engineered exosomes cRGD-Exo-MEG3 could deliver more efficiently to OS cells both in vitro and in vivo. In this way, cRGD-Exo-MEG3 facilitate the anti-OS effects of MEG3 significantly, with the help of enhanced tumor-targeting therapy. This study elucidates that engineered exosomes as targeted lncRNA MEG3 delivery vehicles have potentially therapeutic effects for OS.

LncRNA MEG3 restrained pulmonary fibrosis induced by NiO NPs via regulating hedgehog signaling pathway-mediated autophagy

Long noncoding RNA maternally expressed gene 3 (lncRNA MEG3) was down-regulated in pulmonary fibrosis of rats induced by Nickel oxide nanoparticles (NiO NPs), while the downstream regulatory mechanisms of MEG3 remain unclear. This study aimed to investigate the relationship among MEG3, Hedgehog (Hh) signaling pathway and autophagy in pulmonary fibrosis caused by NiO NPs. The pulmonary fibrosis model in rats was constructed by intratracheal instillation of 0.015, 0.06, and 0.24 mg/kg NiO NPs twice a week for 9 weeks. Collagen deposition model was established by treating A549 cells with 25, 50, and 100 μg/mL NiO NPs for 24 h. Our results indicated that NiO NPs activated Hh pathway, down-regulated the expression of MEG3, and reduced autophagy activity in vivo and in vitro. Meanwhile, the autophagy process was promoted by Hh pathway inhibitor (CDG-0449), while the collagen formation in A549 cells was reduced by autophagy activator (Rapamycin). Furthermore, the overexpressed MEG3 inhibited the activation of Hh pathway, resulting in autophagy activity enhancement along with collagen formation reduction. In summary, lncRNA MEG3 can restrain pulmonary fibrosis induced by NiO NPs via regulating hedgehog signaling pathway-mediated autophagy, which may serve as a potential therapeutic strategy for pulmonary fibrosis.

Long noncoding RNA Meg3 sponges miR-708 to inhibit intestinal tumorigenesis via SOCS3-repressed cancer stem cells growth

BACKGROUND

Colorectal cancer (CRC) remains the most common gastrointestinal cancer and a leading cause of cancer deaths worldwide, with most showing pathologies indicating the malignant transformation of early stage intestinal stem cells. The long non-coding RNA Meg3, which functions as a tumor suppressor, has been reported to be abnormal in multiple tumorigenesis events; however, the underlying mechanism by which Meg3 contributes to the malignant proliferation of colonic stem cells remains unclear.

METHODS

We analyzed the expression levels of Meg3, miR-708, and SOCS3 in samples from Apc loss-of-function (Apc^min) mice and patients with CRC, particularly in colonic crypt cells. Apc^min mice and AMO/DSS-induced mice model (in vivo) and organoid culture system (in vitro) were used to explore the effect of the Meg3/miR-708/SOCS3 axis on tumorigenesis in the colon. In vitro, we performed RNApull-down, RNA immunoprecipitation, and luciferase reporter assays using DLD1 and RKO cell lines.

FINDINGS

The Meg3/miR-708/SOCS3 signaling axis plays a critical role in the early stage of CRC development. Our data showed Meg3 levels negatively correlate with miR-708 levels both in clinical samples and in the Apc^min mouse model, which indicated that Meg3 acts as a competitive endogenous RNA (ceRNA) of miR-708. Then, miR-708 served as an oncogene, inducing neoplasia in both Apc^min mice and cultured colonic organoids. Put together, miR-708 appears to promote malignant proliferation of colonic stem cells by targeting SOCS3/STAT3 signaling.

INTERPRETATION

These data revealed that Meg3 sponges miR-708 to inhibit CRC development via SOCS3-mediated repression of the malignant proliferation of colonic stem cells. The Meg3/miR-708/SOCS3 signaling axis provides potential targets for the diagnosis and treatment of CRC, particularly early stage CRC.

Long non-coding RNA MIR17HG sponges microRNA-21 to upregulate PTEN and regulate homoharringtonine-based chemoresistance of acute myeloid leukemia cells

Long non-coding (lnc)RNA MIR17HG has been identified as a oncogene whose roles in acute myeloid leukemia (AML) remain unclear. The present study aimed to investigate the role of lncRNA MIR17HG in AML. Differential expression of MIR17HG in AML was determined by reverse transcription-quantitative PCR. Overexpression assays and dual luciferase reporter assays were performed to determine the relationship between MIR17HG and microRNA (miR)-21, and apoptosis was analyzed by using an apoptosis assay. The results showed that the expression of MIR17HG was decreased in AML, which was further decreased following homoharringtonine (HHT)-based chemotherapy. Bioinformatics analysis predicted that miR-21 could bind with MIR17HG. However, miR-21 overexpression had no effect on the expression level of MIR17HG. Dual luciferase reporter assays were performed to verify the direct interaction between miR-21 and MIR17HG. In addition, overexpression of MIR17HG and miR-21 in AML cell lines up- and downregulated the expression level of PTEN, respectively. Furthermore, cell apoptosis showed that MIR17HG and PTEN overexpression enhanced cell apoptosis following cell treatment with HTT. However, miR-21 overexpression exerted the opposite effect, since it reversed the effects of MIR17HG and PTEN overexpression in AML cell apoptosis. In conclusion, the current study suggested that MIR17HG could regulate the miR-21/PTEN axis to modulate the chemoresistance of AML cells.

The Role of Long Non-Coding RNAs (lncRNAs) in Female Oriented Cancers

Recent advances in molecular biology have discovered the mysterious role of long non-coding RNAs (lncRNAs) as potential biomarkers for cancer diagnosis and targets for advanced cancer therapy. Studies have shown that lncRNAs take part in the incidence and development of cancers in humans. However, previously they were considered as mere RNA noise or transcription byproducts lacking any biological function. In this article, we present a summary of the progress on ascertaining the biological functions of five lncRNAs (HOTAIR, NEAT1, H19, MALAT1, and MEG3) in female-oriented cancers, including breast and gynecological cancers, with the perspective of carcinogenesis, cancer proliferation, and metastasis. We provide the current state of knowledge from the past five years of the literature to discuss the clinical importance of such lncRNAs as therapeutic targets or early diagnostic biomarkers. We reviewed the consequences, either oncogenic or tumor-suppressing features, of their aberrant expression in female-oriented cancers. We tried to explain the established mechanism by which they regulate cancer proliferation and metastasis by competing with miRNAs and other mechanisms involved via regulating genes and signaling pathways. In addition, we revealed the association between stated lncRNAs and chemo-resistance or radio-resistance and their potential clinical applications and future perspectives.

Impact of microRNA215p on the growth of thyroid cancer cells via targeting the recombinant sclerostin domain containing protein 1

OBJECTIVES

To explore the molecular mechanism for thyroid cancer metastasis via analyzing the role of microRNA (miR)-21-5p and its target gene recombinant sclerostin domain containing protein 1 (SOSTDC1) in thyroid cancer.

METHODS

The target miR-21-5p was screened through bioinformatics analysis and cell verification, and the thyroid cancer cell lines was transfected with miR-21-5p inhibitor. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) test, flow cytometry, and cell scratch test were used to detect the proliferation, apoptosis and migration of thyroid cancer cells in the miR-21-5p inhibitor group and the inhibitor control group, respectively. The luciferase report experiment was used to verify the relationship between miR-21-5p and SOSTDC1, Western blotting was used to detect the expression levels and phosphorylation levels of SOSTDC1,phosphatidylinositol 3 kinase (PI3K), protein kinase B (Akt) and mitogen-activated protein kinases (MAPK), extracellular regulated protein kinases (ERK) in thyroid cancer cells.

RESULTS

MiR-21-5p was significantly increased in thyroid cancer cells,which was negatively correlated with SOSTDC1 (r=-0.24, P<0.01). The proliferation and migration of thyroid cancer cells in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (both P<0.01), and the apoptosis rate in the miR-21-5p inhibitor group was significantly higher than that in the inhibitor control group (P<0.01).The luciferase report experiment showed that miR-21-5p could target and regulate the expression level of SOSTDC1, and the expression of PI3K in the miR-21-5p inhibitor group was significantly lower than that in the inhibitor control group (P<0.01). There were no significant changes in Akt and ERK1/2 levels, but the phosphorylation levels of Akt and ERK1/2 in the miR-21-5p inhibitor group were significantly lower than those in the inhibitor control group (both P<0.01).

CONCLUSIONS

MiR-21-5p in thyroid cancer cells can target the expression of SOSTDC1 and affect the activities of PI3K/Akt and MAPK/ERK, thereby inhibiting the apoptosis of thyroid cancer cells and promoting cell proliferation and migration.

The role of long noncoding RNAs in patients with Luminal A invasive breast ductal carcinoma

Breast cancer is the most common form of cancer in women around the world. The molecular mechanisms of this heterogeneous disease have been extensively investigated; but yet; It requires a lot of sensitive and specific markers for prognosis and early detection approaches. Non-protein coding RNAs known as lncRNAs have been reported in tumorigenic involvement so they can be used for therapeutic purposes. In the present study, the expression levels of CCAT1, PDCD4, PDCD4-AS1, and MEG3 LncRNA in adjacent tumor and breast tissue in 88 Iranian patients were evaluated by quantitative real-time PCR. CCAT1 was significantly expressed and PDCD4-AS1 decreased in tumor samples, PDCD4 and PDCD4-AS1 showed a positive correlation with each other, higher levels of PDCD4-AS1 were associated with better survival, tumor samples showed lower levels of PDCD4 in Showed comparisons with normal tissue. Our findings suggest that lncRNAs play an important role in controlling gene expression after transcription of major tumor suppressors or carcinogenic genes, leading to the development of triple-negative breast cancer (TNBC). In conclusion, this study investigated the prognostic role of lncRNA in breast cancer patients.

UNC5B-AS1 promotes the proliferation, migration and EMT of hepatocellular carcinoma cells via regulating miR-4306/KDM2A axis

Being one of the most prevalent malignancies, hepatocellular carcinoma (HCC) threatens the health of population all over the world. Numerous researches have confirmed that long noncoding RNAs (lncRNAs) play an important role in tumor progression. Nonetheless, the mechanisms of unc-5 netrin receptor B antisense RNA 1 (UNC5B-AS1) in HCC remain obscure. Thus, this study aims to investigate the regulatory role and mechanism of UNC5B-AS1 in HCC cells. In our research, UNC5B-AS1 was subjected to gene expression analysis by RT-qPCR. Biological functions of UNC5B-AS1 in HCC cells were measured by MTT, colony formation, EdU and transwell assays. The combination between UNC5B-AS1, lysine demethylase 2A (KDM2A) and miR-4306 was validated by mechanism assays. Result showed UNC5B-AS1 was upregulated in HCC tissues and cells, contributing to the development of cancer staging and survival rate of HCC patients. Moreover, UNC5B-AS1 deficiency inhibited the proliferation, migration and epithelial-mesenchymal transition (EMT) of HCC cells. Furthermore, UNC5B-AS1 could interact with miR-4306 in HCC cells. Similarly, KDM2A was proved as the target gene of miR-4306. Finally, miR-4306 downregulation or KDM2A overexpression reversed the prohibitive role of UNC5B-AS1 knockdown in HCC progression. In short, UNC5B-AS1 accelerates the proliferation, migration and EMT of HCC cells via the regulation of miR-4306/KDM2A axis.

Maternally expressed 3 inhibits the biological activity of oral squamous cell carcinoma SCC25 and CAL27 cell lines

The abnormal expression of long non-coding RNA (lncRNA) maternally expressed 3 (MEG3) is closely related to several tumor diagnosis and progression, such as endometrial carcinoma and ovarian cancer. However, the role of MEG3 in oral squamous cell carcinoma (OSCC) is rarely reported. The current study aimed to evaluate the expression of lncRNA MEG3 in OSCC tissues and cell lines and its effect on the biological behavior of OSCC cell lines. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was detected by reverse transcription-quantitative (RT-q) PCR. The relationship between MEG3 expression and the clinicopathologic characteristics and prognosis of patients with OSCC was analyzed. The lncRNA MEG3 overexpression plasmid and control plasmid were transfected into SCC25 and CAL27 cell lines using the lipofectin method. MTT assay was performed to detect the growth and proliferation of the cell lines. Transwell chamber test was used to detect changes in cell migration and invasion. Flow cytometry was employed to detect changes in apoptosis. Western blotting and RT-qPCR were conducted to detect the expression of the p53 gene. The expression of lncRNA MEG3 in the OSCC tissues and cell lines was significantly compared with normal tissues and cell lines, respectively. The expression level of MEG3 was related to clinical stage, lymph node metastasis, distant metastasis and survival status. Overexpression of lncRNA MEG3 inhibited the proliferation, migration, and invasion of SCC25 and CAL27 cell lines, induced apoptosis and promoted the expression of p53 gene. lncRNA MEG3 played the role of a tumor inhibitor gene and significantly inhibited the biological activity of OSCC cell lines, which may provide a novel idea for molecular targeted therapy of OSCC.

Long Non-coding RNAs in Pathogenesis of Neurodegenerative Diseases

Emerging evidence addresses the link between the aberrant epigenetic regulation of gene expression and numerous diseases including neurological disorders, such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD). LncRNAs, a class of ncRNAs, have length of 200 nt or more, some of which crucially regulate a variety of biological processes such as epigenetic-mediated chromatin remodeling, mRNA stability, X-chromosome inactivation and imprinting. Aberrant regulation of the lncRNAs contributes to pathogenesis of many diseases, such as the neurological disorders at the transcriptional and post-transcriptional levels. In this review, we highlight the latest research progress on the contributions of some lncRNAs to the pathogenesis of neurodegenerative diseases via varied mechanisms, such as autophagy regulation, Aβ deposition, neuroinflammation, Tau phosphorylation and α-synuclein aggregation. Meanwhile, we also address the potential challenges on the lncRNAs-mediated epigenetic study to further understand the molecular mechanism of the neurodegenerative diseases.

LncRNA OIP5-AS1 Regulates the Warburg Effect Through miR-124-5p/IDH2/HIF-1α Pathway in Cervical Cancer

Hypoxia reprogrammed glucose metabolism affects the Warburg effect of tumor cells, but the mechanism is still unclear. Long-chain non-coding RNA (lncRNA) has been found by many studies to be involved in the Warburg effect of tumor cells under hypoxic condition. Herein, we find that lncRNA OIP5-AS1 is up-regulated in cervical cancer tissues and predicts poor 5-years overall survival in cervical cancer patients, and it promotes cell proliferation of cervical cancer cells in vitro and in vivo. Moreover, OIP5-AS1 is a hypoxia-responsive lncRNA and is essential for hypoxia-enhanced glycolysis which is IDH2 or hypoxia inducible factor-1α (HIF-1α) dependent. In cervical cancer cells, OIP5-AS1 promotes IDH2 expression by inhibiting miR-124-5p, and IDH2 promotes the Warburg effect of cervical under hypoxic condition through regulating HIF-1α expression. In conclusion, hypoxia induced OIP5-AS1 promotes the Warburg effect through miR-124-5p/IDH2/HIF-1α pathway in cervical cancer.

Long Non-Coding RNAs as Potential Diagnostic and Prognostic Biomarkers in Breast Cancer: Progress and Prospects

Breast cancer is the most common malignancy among women worldwide, excluding non-melanoma skin cancer. It is now well understood that breast cancer is a heterogeneous entity that exhibits distinctive histological and biological features, treatment responses and prognostic patterns. Therefore, the identification of novel ideal diagnostic and prognostic biomarkers is of utmost importance. Long non-coding RNAs (lncRNAs) are commonly defined as transcripts longer than 200 nucleotides that lack coding potential. Extensive research has shown that lncRNAs are involved in multiple human cancers, including breast cancer. LncRNAs with dysregulated expression can act as oncogenes or tumor-suppressor genes to regulate malignant transformation processes, such as proliferation, invasion, migration and drug resistance. Intriguingly, the expression profiles of lncRNAs tend to be highly cell-type-specific, tissue-specific, disease-specific or developmental stage-specific, which makes them suitable biomarkers for breast cancer diagnosis and prognosis.

LncRNA GACAT1 induces tongue squamous cell carcinoma migration and proliferation via miR-149

Recent studies have observed that lncRNAs (long non‐coding RNAs) are involved in the progression of various tumours including tongue squamous cell carcinoma (TSCC). Recently, a new lnRNA, GACAT1, has been firstly identified in gastric cancer. However, its potential role in TSCC remains unknown. In this reference, we observed that GACAT1 was overexpressed in TSCC samples and cell lines. Of 25 TSCC specimens, GACAT1 expression was overexpressed in 18 patients (18/25, 72%) compared to non‐tumour specimens. Ectopic expression of GACAT1 induced cell growth and migration and promoted epithelial to mesenchymal transition in TSCC. In addition, ectopic expression of GACAT1 decreased miR‐149 expression in SCC1 cell. We observed that miR‐149 expression was down‐regulated in TSCC cell lines. Moreover, we observed that GACAT1 expression was negatively correlated with miR‐149 expression. GACAT1 overexpression induced TSCC cell growth and migration via regulating miR‐149 expression. These data provided that GACAT1 played an oncogenic role in the progression of TSCC partly through modulating miR‐149 expression.

The long noncoding RNA MEG3 regulates Ras-MAPK pathway through RASA1 in trophoblast and is associated with unexplained recurrent spontaneous abortion

Background

Maternally Expressed Gene 3 (MEG3) is expressed at low levels in placental villi during preeclampsia; however, its roles in unexplained recurrent spontaneous abortion (URSA) remain unclear. In this study, we aimed to explore the relationship between MEG3 and URSA.

Methods

The differentially expressed lncRNAs (MEG3) and its downstream genes (RASA1) were identified using bioinformatics analysis of Genomic Spatial Event (GSE) database. The expression levels of MEG3 in embryonic villis (with gestational ages of 49–63 days) and primary trophoblasts were determined using quantitative RT-PCR assay. A mouse model of Embryo implantation, Cell Counting Kit-8 (CCK-8), flow cytometry, and Transwell migration assays were performed to determine the implantation, proliferative, apoptotic, and invasive capacities of trophoblast. The level of phosphorylated core proteins in the RAS-MAPK pathway were analyzed using Western blot assay. The mechanisms of MEG3 in the regulation of RASA1 were studied by RNA pulldown, RNA immunoprecipitation (RIP), DNA pulldown, and chromatin immunoprecipitation (ChIP) assays.

Results

MEG3 had a low expression level in embryonic villis of 102 URSA patients compared with those of 102 normal pregnant women. MEG3 could promote proliferation and invasion, inhibit the apoptosis of primary trophoblast of URSA patients (PT-U cells), as well as promote embryo implantation of mouse. Besides, MEG3 also promoted the phosphorylation of rapidly accelerated fibrosarcoma (Raf), mitogen-activated protein kinase kinase (MEK), and extracellular-signal-regulated kinase (ERK) proteins. The results of RNA pull down and RIP assays showed that MEG3 bound with the enhancer of zeste homolog 2 (EZH2). The DNA pulldown assay revealed that MEG3 could bind to the promoter sequence of the RAS P21 Protein Activator 1 (RASA1) gene. Further, the ChIP assay showed that MEG3 promoted the binding of EZH2 to the promoter region of the RASA1 gene.

Conclusions

The inactivation of MEG3 in embryonic villi association with URSA; MEG3 inhibited the expression of RASA1 by mediating the histone methylation of the promoter of RASA1 gene by EZH2, thereby activating the RAS-MAPK pathway and enhancing the proliferative and invasive capacities of trophoblasts.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00337-9.

Long non-coding RNA BRE-AS1 inhibits the proliferation, migration, and invasion of cancer cells in triple-negative breast cancer and predicts patients' survival by downregulating miR-21

Background

BRE-AS1 is a recently identified tumor suppressor in non-small cell lung cancer. It role in other human diseases remains elusive.

Methods

Differential expression of BRE-AS1 in with triple-negative breast cancer (TNBC) patients (n = 74, patient group) and healthy volunteers (n = 58, control group) was studied with RT-qPCR. The direct interaction between BRE-AS1 and premature microRNA-21 (miR-21) was assessed by RNA pull-down assay. The interactions among BRE-AS1, miR-21 and PTEN were evaluated by overexpression assays. CCK-8 assay and Transwell assay were used to evaluate cell behaviors.

Results

BRE-AS1 was downregulated in TNBC, while miR-21 was highly expressed in TNBC. Low expression levels of lncRNA BRE-AS1 and high expression levels of miR-21 were significantly correlated with unfavorable survival outcomes. BRE-AS1 and miRNA-21 were inversely correlated across TNBC samples, not control samples. BRE-AS1 decreased miR-21 expression and increased PTEN expression while miR-21showed no role in BRE-AS1 expression. RNA pull-down assay illustrated that BRE-AS1 may sponge premature miR-21 to suppress it maturation. Overexpression of BRE-AS1 decreased cell behaviors, while overexpression of miR-21 promoted cell behaviors. MiR-21 suppressed the role of BRE-AS1 in cancer cell behaviors.

Conclusion

Therefore, BRE-AS1 may inhibit TNBC by downregulating miR-21.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08294-6.

An Overview of the Role of Long Non-Coding RNAs in Human Choriocarcinoma

Choriocarcinoma (CC), a subtype of trophoblastic disease, is a rare and highly aggressive neoplasm. There are two main CC subtypes: gestational and non-gestational, (so called when it develops as a component of a germ cell tumor or is related to a somatic mutation of a poorly differentiated carcinoma), each with very diverse biological activity. A therapeutic approach is highly effective in patients with early-stage CC. The advanced stage of the disease also has a good prognosis with around 95% of patients cured following chemotherapy. However, advancements in diagnosis and treatment are always needed to improve outcomes for patients with CC. Long non-coding (lnc) RNAs are non-coding transcripts that are longer than 200 nucleotides. LncRNAs can act as oncogenes or tumor suppressor genes. Deregulation of their expression has a key role in tumor development, angiogenesis, differentiation, migration, apoptosis, and proliferation. Furthermore, detection of cancer-associated lncRNAs in body fluids, such as blood, saliva, and urine of cancer patients, is emerging as a novel method for cancer diagnosis. Although there is evidence for the potential role of lncRNAs in a number of cancers of the female genital tract, their role in CC is poorly understood. This review summarizes the current knowledge of lncRNAs in gestational CC and how this may be applied to future therapeutic strategies in the treatment of this rare cancer.

PP7080 expedites the proliferation and migration of lung adenocarcinoma cells via sponging miR-670-3p and regulating UHRF1BP1

BACKGROUND

An increasing body of evidence has revealed that long non-coding RNAs play a significant part in a variety of human cancers, including lung adenocarcinoma (LUAD).

METHODS

The expression of PP7080, miR-670-3p and UHRF1BP1 in LUAD cells and tissues was detected using a quantitative real-time polymerase chain reaction. The role of PP7080 in LUAD cells was validated by CCK-8, flow cytometry, colony formation, transwell and wound healing assays. The binding capacity between PP7080/UHRF1BP1 and miR-670-3p was confirmed by luciferase reporter assays. Moreover, the interactional mechanism among PP7080, miR-670-3p and UHRF1BP1 was determined by means of RNA immunoprecipitation and western blot assays.

RESULTS

The expression level of PP7080 is up-regulated in LUAD cells and tissues compared to their matched controls. Down-regulation of PP7080 restrained the proliferative and migratory abilities of LUAD cells, but induced cell apoptosis. PP7080 up-regulation led to the opposite results. Moreover, the binding ability between miR-670-3p and PP7080/UHRF1BP1 in LUAD cells was confirmed. A rescue assay revealed that PP7080 contributes to LUAD development by modulating the miR-670-3p/UHRF1BP1 signaling pathway.

CONCLUSIONS

PP7080 expedites the proliferation and migration of LUAD cell via sponging miR-670-3p and modulating UHRF1BP1.