Long Non-coding RNA NEAT1 as an Emerging Biomarker in Breast and Gynecologic Cancers: a Systematic Overview

The regulation of hypoxia-related lncRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is still a public health disease with its high prevalence and morbidity. Short of early diagnosis biomarkers and effective therapy, the treatment of HCC patients hasn't achieved ideal effect. Hypoxia is a hallmark of HCC, which is mainly induced by imbalance of tumor cell proliferation and insufficient supply of oxygen. Recently, amounting evidence suggested lncRNAs, especially hypoxia-related lncRNAs play a pivotal role in regulating HCC. Hypoxia-related lncRNAs are involved in altering glucose metabolism, maintaining of cancer stem cell-like properties (CSCs), cell apotosis, proliferation and immune escape, which all contribute to the poor prognosis of HCC patients. The novel identified hypoxia-related lncRNAs could be the potential target or biomarkers of HCC, which are beneficial to the clinical treatment. Herein, we summarized currently reported hypoxia-related lncRNAs and their related mechanisms, providing potential application and future perspective of hypoxia-related lncRNAs as a potential therapeutic target.

The mechanisms and diagnostic potential of lncRNAs, miRNAs, and their related signaling pathways in cervical cancer

Cervical cancer (CC), the fourth most prevalent type of cancer among women worldwide, is associated with high rates of morbidity and mortality. Due to the long period of latency in CC, most patients are already in the middle to late stages when initially diagnosed, which greatly reduces the clinical cure rate and quality of survival, thus resulting in poor outcomes. In recent years, with continuous exploration in the fields of bioinformatics and molecules, it has been found that ncRNAs, including miRNAs and lncRNAs, without the ability to translate proteins are capable of activating or inhibiting certain signaling pathways by targeting and modulating the level of expression of proteins involved in these signaling pathways. ncRNAs play important roles in assisting with diagnosis, drug administration, and prediction of prognosis during CC progression. As an entry point, the mechanisms of interaction between miRNAs, lncRNAs, and signaling pathways have long been a focus in basic research relating to CC, and numerous experimental studies have confirmed the close relationship of miRNAs, lncRNAs, and signaling pathways with CC development. Against this background, we summarize the latest advances in the involvement of lncRNA- and miRNA-related signaling pathways in the development of CC to provide guidance for CC treatment.

LncRNA NEAT1 regulates HCV-induced Hepatocellular carcinoma by modulating the miR-9-BGH3 axis

Chronic hepatitis C virus (HCV) infection is a leading cause of end-stage liver diseases, such as fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Several cellular entities, including paraspeckles and their related components, are involved in viral pathogenesis and cancer progression. NEAT1 lncRNA is a major component of paraspeckles that has been linked to several malignancies. In this study, analysis of the Cancer Genome Atlas (TCGA) database and validation in HCV-induced HCC tissue and serum samples showed significantly high expression of NEAT1 in patients with liver cancer. Moreover, we found that NEAT1 levels increased upon HCV infection. To further understand the mechanism of NEAT1-induced HCC progression, we selected one of its targets, miR-9-5 p, which regulates BGH3 mRNA levels. Interestingly, miR-9-5 p levels were downregulated upon HCV infection, whereas BGH3 levels were upregulated. Additionally, partial NEAT1 knockdown increased miR-9-5 p levels and decreased BGH3 levels, corroborating our initial results. BGH3 levels were also upregulated in HCV-induced HCC and TCGA tissue samples, which could be directly correlated with NEAT1 levels. As a known oncogene, BGH3 is directly linked to HCC progression mediated by NEAT1. We also found that NEAT1 levels remained upregulated in serum samples from patients treated with direct-acting antivirals (DAA), indicating that NEAT1 might be a molecular trigger that promotes HCC development. Collectively, these findings provide molecular insights into HCV-induced HCC progression via the NEAT1-miR-9-BGH3 axis.

Assessing the suitability of long non-coding RNAs as therapeutic targets and biomarkers in SARS-CoV-2 infection

Long non-coding RNAs (lncRNAs) are RNA transcripts that are over 200 nucleotides and rarely encode proteins or peptides. They regulate gene expression and protein activities and are heavily involved in many cellular processes such as cytokine secretion in respond to viral infection. In severe COVID-19 cases, hyperactivation of the immune system may cause an abnormally sharp increase in pro-inflammatory cytokines, known as cytokine release syndrome (CRS), which leads to severe tissue damage or even organ failure, raising COVID-19 mortality rate. In this review, we assessed the correlation between lncRNAs expression and cytokine release syndrome by comparing lncRNA profiles between COVID-19 patients and health controls, as well as between severe and non-severe cases. We also discussed the role of lncRNAs in CRS contributors and showed that the lncRNA profiles display consistency with patients’ clinic symptoms, thus suggesting the potential of lncRNAs as drug targets or biomarkers in COVID-19 treatment.

Expression and functions of long non-coding RNA NEAT1 and isoforms in breast cancer

NEAT1 is a highly abundant nuclear architectural long non-coding RNA. There are two overlapping NEAT1 isoforms, NEAT1_1 and NEAT1_2, of which the latter is an essential scaffold for the assembly of a class of nuclear ribonucleoprotein bodies called paraspeckles. Paraspeckle formation is elevated by a wide variety of cellular stressors and in certain developmental processes, either through transcriptional upregulation of the NEAT1 gene or through a switch from NEAT1_1 to NEAT1_2 isoform production. In such conditions, paraspeckles modulate cellular processes by sequestering proteins or RNA molecules. NEAT1 is abnormally expressed in many cancers and a growing body of evidence suggests that, in many cases, high NEAT1 levels are associated with therapy resistance and poor clinical outcome. Here we review the current knowledge of NEAT1 expression and functions in breast cancer, highlighting its established role in postnatal mammary gland development. We will discuss possible isoform-specific roles of NEAT1_1 and NEAT1_2 in different breast cancer subtypes, which critically needs to be considered when studying NEAT1 and breast cancer.

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

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

ADSC Exosomes Mediate lncRNA-MIAT Alleviation of Endometrial Fibrosis by Regulating miR-150-5p

Background

Secondary infertility remains a major complication of endometrial fibrosis in women. The use of exosomes from adipose-derived mesenchymal stem cells (ADSCs) has shown promising results for the treatment of endometrial fibrosis. However, the mechanisms of action of ADSC-exosome (ADSC-Exo) therapy remain unclear.

Materials and Methods

An endometrial fibrosis model was established in mice treated with alcohol and endometrial epithelial cells (ESCs) treated with TGF-β1. ADSCs were isolated from Sprague Dawley (SD) rats, and exosomes were isolated from ADSCs using ExoQuick reagent. Exosomes were identified by transmission electron microscopy (TEM), NanoSight, and Western blot analysis. The expression level of lncRNA-MIAT was detected by qPCR analysis. Western blot analysis was carried out to determine the protein levels of fibrosis markers (TGFβR1, α-SMA, and CK19). A dual-luciferase reporter gene assay was used to verify the relationship between target genes. The endometrial tissues of the endometrial fibrosis model were stained with HE and Masson’s trichrome.

Results

ADSCs and ADSC-Exos were successfully isolated, and the expression level of lncRNA-MIAT was significantly down-regulated in endometrial tissue and the TGF-β1-induced ESC injury model, whereas ADSC-Exos increased the expression of lncRNA-MIAT in the TGF-β1-induced ESC model. Functionally, ADSC-Exo treatment repressed endometrial fibrosis in vivo and in vitro by decreasing the expression of hepatic fibrosis markers (α-SMA and TGFβR1) and increasing the expression of CK19. Moreover, miR-150-5p expression was repressed by lncRNA-MIAT in the TGF-β1-induced ESC injury model. The miR-150-5p mimic promoted TGF-β1-induced ESC fibrosis.

Conclusion

ADSC-Exos mediate lncRNA-MIAT alleviation of endometrial fibrosis by regulating miR-150-5p, which suggests that lncRNA-MIAT from ADSC-Exos may be a viable treatment for endometrial fibrosis.