LncRNA NEAT1 contributes to paclitaxel resistance of ovarian cancer cells by regulating ZEB1 expression via miR-194

Dysregulated circular RNA and long non-coding RNA-Mediated regulatory competing endogenous RNA networks (ceRNETs) in ovarian and cervical cancers: A non-coding RNA-Mediated mechanism of chemotherapeutic resistance with new emerging clinical capacities

Cervical cancer (CC) and ovarian cancer (OC) are among the most common gynecological cancers with significant mortality in women, and their incidence is increasing. In addition to the prominent role of the malignant aspect of these cancers in cancer-related women deaths, chemotherapy drug resistance is a major factor that contributes to their mortality and presents a clinical obstacle. Although the exact mechanisms behind the chemoresistance in these cancers has not been revealed, accumulating evidence points to the dysregulation of non-coding RNAs (ncRNAs), particularly long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as key contributors. These ncRNAs perform the roles of regulators of signaling pathways linked to tumor formation and chemoresistance. Strong data from various recent studies have uncovered that the main mechanism of these ncRNAs in the induction of chemoresistance of CC and OC is done through a dysregulated miRNA sponge activity as competing endogenous RNA (ceRNA) in the competing endogenous RNA networks (ceRNETs), where a miRNA regulating a messenger RNA (mRNA) is trapped, thereby removing its inhibitory effect on the desired mRNA. Understanding these mechanisms is essential to enhancing treatment outcomes and managing the problem of drug resistance. This review provides a comprehensive overview of lncRNA- and circRNA-mediated ceRNETs as the core process of chemoresistance against the commonly used chemotherapeutics, including cisplatin, paclitaxel, oxaliplatin, carboplatin, and docetaxel in CC and OC. Furthermore, we highlight the clinical potential of these ncRNAs serving as diagnostic indicators of chemotherapy responses and therapeutic targets.

Overcoming drug resistance in ovarian cancer through PI3K/AKT signaling inhibitors

Ovarian cancer has been identified as the eighth most typical gynaecological malignancy and cause of health problems in women. For almost forty years, platinum doublet chemotherapy has usually been the cornerstone of first-line treatment regimens. The effectiveness of conventional chemotherapy is severely hampered by relapse rates and mortality from chemotherapy resistance, which lead to the spread and recurrence of malignant cancers as well as poor outcomes in terms of quality of life in patients. Drug resistance has been linked to several mechanisms, including increased drug efflux, decreased apoptosis, increased autophagy, and changed drug metabolism. Further, the dysregulation of tumor suppressors or oncogenes plays a crucial role in chemoresistance. Additionally, PI3K/AKT/mTOR signaling has been implicated in several in vitro as well as clinical studies as a significant contributor to chemotherapy resistance in case of ovarian cancer. This review discusses the potential of various crude extracts, synthetic molecules, and nanoformulations for targeting PI3K/AKT/mTOR pathway. Moreover, a range of clinical studies involving PI3K/AKT/mTOR inhibitors have been summed up, addressing both the promises and complexities associated with their use. Overall, the review aims to provide a roadmap for future investigations that could lead to improved therapeutic outcomes for patients suffering from ovarian cancer, emphasizing the urgent need for continued exploration of novel pathways and strategies to combat drug resistance.

Latest Update on lncRNA in Epithelial Ovarian Cancer-A Scoping Review

Long noncoding RNAs (lncRNAs) are RNA molecules exceeding 200 nucleotides that do not encode proteins yet play critical roles in regulating gene expression at multiple levels, such as chromatin modification and transcription. These molecules are significantly engaged in cancer progression, development, metastasis, and chemoresistance. However, the function of lncRNAs in epithelial ovarian cancer (EOC) has not yet been thoroughly studied. EOC remains challenging due to its complex molecular pathogenesis, characterized by genetic and epigenetic alterations. Emerging evidence suggests that lncRNAs, such as XIST, H19, NEAT1, and MALAT1, are involved in EOC by modulating gene expression and signaling pathways, influencing processes like cell proliferation, invasion, migration, and chemoresistance. Despite extensive research, the precise mechanism of acting of lncRNAs in EOC pathogenesis and treatment resistance still needs to be fully understood, highlighting the need for further studies. This review aims to provide an updated overview of the current understanding of lncRNAs in EOC, emphasizing their potential as biomarkers and therapeutic targets. We point out the gaps in the knowledge regarding lncRNAs' influence on epithelial ovarian cancer (EOC), deliberating on new possible research areas.

Mechanisms behind the LncRNAs-mediated regulation of paclitaxel (PTX) resistance in human malignancies

Paclitaxel (PTX) is extensively used to treat various cancers, including those of the breast, ovary, lung, esophagus, stomach, pancreas, and neck. However, despite its effectiveness in clinical settings, patients often experience cancer recurrence due to the emergence of resistance to PTX. The mechanisms underlying this resistance in cancer cells exposed to PTX involve modifications in β-tubulin, the primary target molecule associated with mitosis, the activation of pathways that facilitate drug efflux, and the dysregulation of apoptosis-related proteins. Long non-coding RNAs (lncRNAs), which are RNA molecules exceeding 200 nucleotides in length and lacking protein-coding capabilities, play various regulatory roles in cellular functions. A growing body of evidence underscores the role of lncRNAs in cancer progression and their involvement in PTX resistance across different cancer types. As a result, lncRNAs have been identified as promising therapeutic targets for overcoming drug resistance in cancer therapies. This review aims to provide an overview of the current knowledge regarding lncRNAs and their contributions to resistance mechanisms to promote further research in this field. A summary of key lncRNAs and their related pathways associated with PTX resistance will be presented.

An overview of lncRNA NEAT1 contribution in the pathogenesis of female cancers; from diagnosis to therapy resistance

Despite the ongoing progress in detecting and treating cancer, there is still a need for extensive research into the molecular mechanisms involved in the emergence, progression, and resistance to recurrence of female reproductive tissue-specific cancers such as ovarian, breast, cervical, and endometrial cancers. The nuclear paraspeckle assembly transcript 1 (NEAT1) is a long non-coding RNA (lncRNA) that exhibits increased expression in female tumors. Moreover, elevated levels of NEAT1 have been associated with poorer survival outcomes in cancer patients. NEAT1 plays a pivotal role in driving tumor initiation through modulating the expression of genes involved in various aspects of tumor cell proliferation, epithelial-to-mesenchymal transition (EMT), metastasis, chemoresistance, and radio-resistance. Mechanistically, NEAT1 acts as a scaffold RNA molecule via interacting with EZH2 (Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit), thereby influencing the expression of downstream effectors of EZH2. Additionally, NEAT1 functions as a competing endogenous RNA (ceRNA) by microRNAs (miRNAs) sponging, consequently altering the expression levels of their target genes during the development of female cancers. This comprehensive review aims to shed light on the latest insights regarding the expression pattern, biological functions, and underlying mechanisms governing the function and regulation of NEAT1 in tumors. Furthermore, particular emphasis is placed on its clinical significance as a novel diagnostic biomarker and a promising therapeutic target for female cancers.

Competing endogenous RNA networks in ovarian cancer: from bench to bedside

Epithelial ovarian cancer is responsible for the majority of ovarian malignancies, and its highly invasive nature and chemoresistant development have been major obstacles to treating patients with mainstream treatments. In recent decades, the significance of microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and competing endogenous RNAs (ceRNAs) has been highlighted in ovarian cancer development. This hidden language between these RNAs has led to the discovery of enormous regulatory networks in ovarian cancer cells that substantially affect gene expression. Aside from providing ample opportunities for targeted therapies, circRNA- and lncRNA-mediated ceRNA network components provide invaluable biomarkers. The current study provides a comprehensive and up-to-date review of the recent findings on the significance of these ceRNA networks in the hallmarks of ovarian cancer oncogenesis, treatment, diagnosis, and prognosis. Also, it provides the authorship with future perspectives in the era of single-cell RNA sequencing and personalized medicine.

Ferroptosis contributes to the progression of female-specific neoplasms, from breast cancer to gynecological malignancies in a manner regulated by non-coding RNAs: Mechanistic implications

Ferroptosis, a recently identified type of non-apoptotic cell death, triggers the elimination of cells in the presence of lipid peroxidation and in an iron-dependent manner. Indeed, ferroptosis-stimulating factors have the ability of suppressing antioxidant capacity, leading to the accumulation of reactive oxygen species (ROS) and the subsequent oxidative death of the cells. Ferroptosis is involved in the pathophysiological basis of different maladies, such as multiple cancers, among which female-oriented malignancies have attracted much attention in recent years. In this context, it has also been unveiled that non-coding RNA transcripts, including microRNAs, long non-coding RNAs, and circular RNAs have regulatory interconnections with the ferroptotic flux, which controls the pathogenic development of diseases. Furthermore, the potential of employing these RNA transcripts as therapeutic targets during the onset of female-specific neoplasms to modulate ferroptosis has become a research hotspot; however, the molecular mechanisms and functional alterations of ferroptosis still require further investigation. The current review comprehensively highlights ferroptosis and its association with non-coding RNAs with a focus on how this crosstalk affects the pathogenesis of female-oriented malignancies, from breast cancer to ovarian, cervical, and endometrial neoplasms, suggesting novel therapeutic targets to decelerate and even block the expansion and development of these tumors.

LncRNA EIF3J-DT promotes chemoresistance in oral squamous cell carcinoma

OBJECTIVES

This study aimed to screen oral squamous cell carcinoma (OSCC) diagnostic and prognostic candidates and investigate the potential functions and mechanisms of candidates in the chemoresistance of OSCC cell lines.

MATERIALS AND METHODS

Differential expression profiling of lncRNA was performed in a large cohort of OSCC patients from the Cancer Genome Atlas database to identify OSCC diagnostic and prognostic candidates. Taxol resistance in OSCC cell lines was analyzed using MTT assay. OSCC cell lines transfected with EIF3J-DT pcDNA or siRNA were used to determine its regulatory effects on apoptosis, cell cycle distribution and autophagy using flow cytometry and western blot.

RESULTS

We identified EIF3J-DT as a candidate for OSCC diagnosis and prognosis. The expression level of EIF3J-DT in OSCC cell lines correlates with taxol resistance. EIF3J-DT silencing attenuated taxol resistance, and EIF3J-DT overexpression enhanced taxol resistance in OSCC cell lines. Silencing of EIF3J-DT reduced taxol resistance by inducing apoptosis, cell cycle arrest, and ATG14-mediated autophagy inhibition in OSCC cell lines.

CONCLUSIONS

We found that EIF3J-DT induced chemoresistance by regulating apoptosis, cell cycle, and autophagy in OSCC cell lines, which EIF3J-DT might provide a novel therapeutic approach for OSCC as well as a diagnostic and prognostic factor.

Long non-coding RNAs: regulators of autophagy and potential biomarkers in therapy resistance and urological cancers

The non-coding RNAs (ncRNAs) comprise a large part of human genome that mainly do not code for proteins. Although ncRNAs were first believed to be non-functional, the more investigations highlighted tthe possibility of ncRNAs in controlling vital biological processes. The length of long non-coding RNAs (lncRNAs) exceeds 200 nucleotidesand can be present in nucleus and cytoplasm. LncRNAs do not translate to proteins and they have been implicated in the regulation of tumorigenesis. On the other hand, One way cells die is by a process called autophagy, which breaks down proteins and other components in the cytoplasm., while the aberrant activation of autophagy allegedly involved in the pathogenesis of diseases. The autophagy exerts anti-cancer activity in pre-cancerous lesions, while it has oncogenic function in advanced stages of cancers. The current overview focuses on the connection between lncRNAs and autophagy in urological cancers is discussed. Notably, one possible role for lncRNAs is as diagnostic and prognostic variablesin urological cancers. The proliferation, metastasis, apoptosis and therapy response in prostate, bladder and renal cancers are regulated by lncRNAs. The changes in autophagy levels can also influence the apoptosis, proliferation and therapy response in urological tumors. Since lncRNAs have modulatory functions, they can affect autophagy mechanism to determine progression of urological cancers.

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.

The Role of Long Non-Coding RNAs in Ovarian Cancer Cells

Among the most deadly malignancies that strike women worldwide, ovarian cancer is still one of the most common. The primary factor affecting a patient's survival is early lesion discovery. Unfortunately, because ovarian cancer is a sneaky illness that usually manifests as nonspecific symptoms only in advanced stages, its early detection and screening are challenging. A lot of research is being conducted on effective methods of diagnosing and treating ovarian cancer. Recently, non-coding RNAs (ncRNAs) have gained great popularity, which are considered to be the main regulators of many cellular processes, especially those occurring in cancer. LncRNAs are also being studied for their therapeutic use in the treatment of ovarian cancer and their use in diagnostics and as indicators of poor prognosis. In this article, we reviewed lncRNAs described in the literature that may play an important role in ovarian cancer.

The crosstalk between non-coding RNAs and cell-cycle events: A new frontier in cancer therapy

The cell cycle comprises sequential events during which a cell duplicates its genome and divides it into two daughter cells. This process is tightly regulated to ensure that the daughter cell receives identical copied chromosomal DNA and that any errors in the DNA during replication are correctly repaired. Cyclins and their enzyme partners, cyclin-dependent kinases (CDKs), are critical regulators of G- to M-phase transitions during the cell cycle. Mitogenic signals induce the formation of the cyclin/CDK complexes, resulting in phosphorylation and activation of the CDKs. Once activated, cyclin/CDK complexes phosphorylate specific substrates that drive the cell cycle forward. The sequential activation and inactivation of cyclin-CDK complexes are tightly controlled by activating and inactivating phosphorylation events induced by cell-cycle proteins. The non-coding RNAs (ncRNAs), which do not code for proteins, regulate cell-cycle proteins at the transcriptional and translational levels, thereby controlling their expression at different cell-cycle phases. Deregulation of ncRNAs can cause abnormal expression patterns of cell-cycle-regulating proteins, resulting in abnormalities in cell-cycle regulation and cancer development. This review explores how ncRNA dysregulation can disrupt cell division balance and discusses potential therapeutic approaches targeting these ncRNAs to control cell-cycle events in cancer treatment.

CSTF3 contributes to platinum resistance in ovarian cancer through alternative polyadenylation of lncRNA NEAT1 and generating the short isoform NEAT1_1

Platinum-based chemotherapy is the standard postoperative adjuvant treatment for ovarian cancer (OC). Despite the initial response to chemotherapy, 85% of advanced OC patients will have recurrent disease. Relapsed disease and platinum resistance are the major causes of death in OC patients. In this study, we compared the global regulation of alternative polyadenylation (APA) in platinum-resistant and platinum-sensitive tissues of OC patients by analyzing a set of single-cell RNA sequencing (scRNA-seq) data from public databases and found that platinum-resistant patients exhibited global 3' untranslated region (UTR) shortening due to the different usage of polyadenylation sites (PASs). The APA regulator CSTF3 was the most significantly upregulated gene in epithelial cells of platinum-resistant OC. CSTF3 knockdown increased the sensitivity of OC cells to platinum. The lncRNA NEAT1 has two isoforms, short (NEAT1_1) and long (NEAT1_2) transcript, because of the APA processing in 3'UTR. We found that CSTF3 knockdown reduced the usage of NEAT1 proximal PAS to lengthen the transcript and facilitate the expression of NEAT1_2. Downregulation of the expression of NEAT1 (NEAT1_1/_2), but not only NEAT1_2, also increased the sensitivity of OC cells to platinum. Overexpressed NEAT1_1 reversed the platinum resistance of OC cells after knocking down CSTF3 expression. Furthermore, downregulated expression of CSTF3 and NEAT1_1, rather than NEAT1_2, was positively correlated with inactivation of the PI3K/AKT/mTOR pathway in OC cells. Together, our findings revealed a novel mechanism of APA regulation in platinum-resistant OC. CSTF3 directly bound downstream of the NEAT1 proximal PAS to generate the short isoform NEAT1_1 and was conducive to platinum resistance, which provides a potential biomarker and therapeutic strategy for platinum-resistant OC patients.

Deciphering the Molecular Mechanisms behind Drug Resistance in Ovarian Cancer to Unlock Efficient Treatment Options

Ovarian cancer is a highly lethal form of gynecological cancer. This disease often goes undetected until advanced stages, resulting in high morbidity and mortality rates. Unfortunately, many patients experience relapse and succumb to the disease due to the emergence of drug resistance that significantly limits the effectiveness of currently available oncological treatments. Here, we discuss the molecular mechanisms responsible for resistance to carboplatin, paclitaxel, polyadenosine diphosphate ribose polymerase inhibitors, and bevacizumab in ovarian cancer. We present a detailed analysis of the most extensively investigated resistance mechanisms, including drug inactivation, drug target alterations, enhanced drug efflux pumps, increased DNA damage repair capacity, and reduced drug absorption/accumulation. The in-depth understanding of the molecular mechanisms associated with drug resistance is crucial to unveil new biomarkers capable of predicting and monitoring the kinetics during disease progression and discovering new therapeutic targets.

Targeting the Warburg effect: A revisited perspective from molecular mechanisms to traditional and innovative therapeutic strategies in cancer

Cancer reprogramming is an important facilitator of cancer development and survival, with tumor cells exhibiting a preference for aerobic glycolysis beyond oxidative phosphorylation, even under sufficient oxygen supply condition. This metabolic alteration, known as the Warburg effect, serves as a significant indicator of malignant tumor transformation. The Warburg effect primarily impacts cancer occurrence by influencing the aerobic glycolysis pathway in cancer cells. Key enzymes involved in this process include glucose transporters (GLUTs), HKs, PFKs, LDHs, and PKM2. Moreover, the expression of transcriptional regulatory factors and proteins, such as FOXM1, p53, NF-κB, HIF1α, and c-Myc, can also influence cancer progression. Furthermore, lncRNAs, miRNAs, and circular RNAs play a vital role in directly regulating the Warburg effect. Additionally, gene mutations, tumor microenvironment remodeling, and immune system interactions are closely associated with the Warburg effect. Notably, the development of drugs targeting the Warburg effect has exhibited promising potential in tumor treatment. This comprehensive review presents novel directions and approaches for the early diagnosis and treatment of cancer patients by conducting in-depth research and summarizing the bright prospects of targeting the Warburg effect in cancer.

Novel players in the development of chemoresistance in ovarian cancer: ovarian cancer stem cells, non-coding RNA and nuclear receptors

Ovarian cancer (OC) ranks as the fifth leading factor for female mortality globally, with a substantial burden of new cases and mortality recorded annually. Survival rates vary significantly based on the stage of diagnosis, with advanced stages posing significant challenges to treatment. OC is primarily categorized as epithelial, constituting approximately 90% of cases, and correct staging is essential for tailored treatment. The debulking followed by chemotherapy is the prevailing treatment, involving platinum-based drugs in combination with taxanes. However, the efficacy of chemotherapy is hindered by the development of chemoresistance, both acquired during treatment (acquired chemoresistance) and intrinsic to the patient (intrinsic chemoresistance). The emergence of chemoresistance leads to increased mortality rates, with many advanced patients experiencing disease relapse shortly after initial treatment. This review delves into the multifactorial nature of chemoresistance in OC, addressing mechanisms involving transport systems, apoptosis, DNA repair, and ovarian cancer stem cells (OCSCs). While previous research has identified genes associated with these mechanisms, the regulatory roles of non-coding RNA (ncRNA) and nuclear receptors in modulating gene expression to confer chemoresistance have remained poorly understood and underexplored. This comprehensive review aims to shed light on the genes linked to different chemoresistance mechanisms in OC and their intricate regulation by ncRNA and nuclear receptors. Specifically, we examine how these molecular players influence the chemoresistance mechanism. By exploring the interplay between these factors and gene expression regulation, this review seeks to provide a comprehensive mechanism driving chemoresistance in OC.

The pivotal role of long non-coding RNAs as potential biomarkers and modulators of chemoresistance in ovarian cancer (OC)

Ovarian cancer (OC) is a fatal gynecological disease that is often diagnosed at later stages due to its asymptomatic nature and the absence of efficient early-stage biomarkers. Previous studies have identified genes with abnormal expression in OC that couldn't be explained by methylation or mutation, indicating alternative mechanisms of gene regulation. Recent advances in human transcriptome studies have led to research on non-coding RNAs (ncRNAs) as regulators of cancer gene expression. Long non-coding RNAs (lncRNAs), a class of ncRNAs with a length greater than 200 nucleotides, have been identified as crucial regulators of physiological processes and human diseases, including cancer. Dysregulated lncRNA expression has also been found to play a crucial role in ovarian carcinogenesis, indicating their potential as novel and non-invasive biomarkers for improving OC management. However, despite the discovery of several thousand lncRNAs, only one has been approved for clinical use as a biomarker in cancer, highlighting the importance of further research in this field. In addition to their potential as biomarkers, lncRNAs have been implicated in modulating chemoresistance, a major problem in OC. Several studies have identified altered lncRNA expression upon drug treatment, further emphasizing their potential to modulate chemoresistance. In this review, we highlight the characteristics of lncRNAs, their function, and their potential to serve as tumor markers in OC. We also discuss a few databases providing detailed information on lncRNAs in various cancer types. Despite the promising potential of lncRNAs, further research is necessary to fully understand their role in cancer and develop effective strategies to combat this devastating disease.

Targeting NEAT1 Affects the Sensitivity to PARPi in Serous Ovarian Cancer by Regulating the Homologous Recombination Repair Pathway

Objective: Patients initially sensitive to PARPi (PARP inhibitor) regain resistance because of homologous recombination (HR) restoration, although PARPi has a synthetic lethality effect on serous ovarian cancer cells with BRCA1/2 mutations. This study aimed to investigate the role of NEAT1 in HR function and whether targeting NEAT1 in serous ovarian cancer cells could increase PARPi sensitivity. Methods: Ovarian cancer patients' clinical information and the expression of NEAT1 were collected from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC). Ovarian cancer (OC) cells HeyA8 and SKOV3 were silenced by transfecting NEAT1 ASO. QRT-PCR confirmed the mRNA expression of RAD51, FOXM1, NEAT1_1 and NEAT1_2. We assessed the expression of RAD51, FOXM1, and γ-H2AX by Western blotting and Immunofluorescence. Comet Assays were used to detect DNA double-strand damage levels. In OC cells transfected with NEAT1 ASO or co-transfected overexpression RAD51/empty vector and si-NEAT1/si-ctrl, the sensitivity to Olaparib was determined using CCK8 assay. The Kaplan-Meier survival curves assessed the prognostic and predictive roles of NEAT1 in OC. Results: NEAT1 was an independent prognostic marker of ovarian cancer. NEAT1 knockdown reduced the expression of NEAT1_1, NEAT1_2, RAD51, and FOXM1 and increased the expression of γ-H2AX. In addition, Olaparib increased the expression of RAD51, representing HR repair efficiency, which was inhibited by NEAT1 knockdown. Moreover, the knockdown of NEAT1 increased the DNA damage caused by Olaparib, demonstrated by increased nuclear γ-H2AX foci, DNA in the tail, and expression of γ-H2AX. NEAT1 knockdown sensitized ovarian cancer cells to Olaparib by targeting RAD51-HR. NEAT1 expression could predict response to chemotherapy for ovarian cancer. Conclusions: NEAT1 knockdown inhibited HR capacity and increased DNA damage caused by Olaparib in serous ovarian cancer cells, making them more sensitive to Olaparib and providing a crucial therapeutic advantage of increasing sensitivity to Olaparib.

Epigenetic modifications: Key players in cancer heterogeneity and drug resistance

Cancer heterogeneity and drug resistance remain pivotal obstacles in effective cancer treatment and management. One major contributor to these challenges is epigenetic modifications - gene regulation that does not involve changes to the DNA sequence itself but significantly impacts gene expression. As we elucidate these phenomena, we underscore the pivotal role of epigenetic modifications in regulating gene expression, contributing to cellular diversity, and driving adaptive changes that can instigate therapeutic resistance. This review dissects essential epigenetic modifications - DNA methylation, histone modifications, and chromatin remodeling - illustrating their significant yet complex contributions to cancer biology. While these changes offer potential avenues for therapeutic intervention due to their reversible nature, the interplay of epigenetic and genetic changes in cancer cells presents unique challenges that must be addressed to harness their full potential. By critically analyzing the current research landscape, we identify knowledge gaps and propose future research directions, exploring the potential of epigenetic therapies and discussing the obstacles in translating these concepts into effective treatments. This comprehensive review aims to stimulate further research and aid in developing innovative, patient-centered cancer therapies. Understanding the role of epigenetic modifications in cancer heterogeneity and drug resistance is critical for scientific advancement and paves the way towards improving patient outcomes in the fight against this formidable disease.

The role of circRNAs in regulation of drug resistance in ovarian cancer

Ovarian cancer is one of the female reproductive system tumors. Chemotherapy is used for advanced ovarian cancer patients; however, drug resistance is a pivotal cause of chemotherapeutic failure. Hence, it is critical to explore the molecular mechanisms of drug resistance of ovarian cancer cells and to ameliorate chemoresistance. Noncoding RNAs (ncRNAs) have been identified to critically participate in drug sensitivity in a variety of human cancers, including ovarian cancer. Among ncRNAs, circRNAs sponge miRNAs and prevent miRNAs from regulation of their target mRNAs. CircRNAs can interact with DNA or proteins to modulate gene expression. In this review, we briefly describe the biological functions of circRNAs in the development and progression of ovarian cancer. Moreover, we discuss the underneath regulatory molecular mechanisms of circRNAs on governing drug resistance in ovarian cancer. Furthermore, we mention the novel strategies to overcome drug resistance via targeting circRNAs in ovarian cancer. Due to that circRNAs play a key role in modulation of drug resistance in ovarian cancer, targeting circRNAs could be a novel approach for attenuation of chemoresistance in ovarian cancer.

ceRNA networks in gynecological cancers progression and resistance

Gynecological cancers are the second most common types of cancer in women. Clinical diagnosis of these cancers is often delayed or misdiagnosed due to lack of insight into their tumorigenesis mechanism and specific diagnostic biomarkers. Many studies have demonstrated that competing endogenous RNAs (ceRNAs) modulate the progression and resistance of gynecological cancer through microRNA (miRNA)-mediated mechanisms, which affect gene expression in multiple cancer-related pathways. Here we review studies on the involvement of the ceRNA hypothesis in the progression and resistance of gynaecological cancers to validate some ceRNAs as therapeutic targets and predictive biomarkers.

Exploring the role of lncrna neat1 knockdown in regulating apoptosis across multiple cancer types: A review

Long non-coding RNAs (lncRNAs) have emerged as pivotal regulators of gene expression, contributing significantly to a diverse range of cellular processes, including apoptosis. One such lncRNA is NEAT1, which is elevated in several types of cancer and aid in cancer growth. However, recent studies have also demonstrated that the knockdown of NEAT1 can inhibit cancer cells proliferation, movement, and infiltration while enhancing apoptosis. This article explores the function of lncRNA NEAT1 knockdown in regulating apoptosis across multiple cancer types. We explore the existing understanding of NEAT1's involvement in the progression of malignant conditions, including its structure and functions. Additionally, we investigate the molecular mechanisms by which NEAT1 modulates the cell cycle, cellular proliferation, apoptosis, movement, and infiltration in diverse cancer types, including acute myeloid leukemia, breast cancer, cervical cancer, colorectal cancer, esophageal squamous cell carcinoma, glioma, non-small cell lung cancer, ovarian cancer, prostate cancer, and retinoblastoma. Furthermore, we review the recent studies investigating the therapeutic potential of NEAT1 knockdown in cancer treatment. Targeting the lncRNA NEAT1 presents a promising therapeutic approach for treating cancer. It has shown the ability to suppress cancer cell proliferation, migration, and invasion while promoting apoptosis in various cancer types.

Emerging roles of the long non-coding RNA NEAT1 in gynecologic cancers

Gynecologic cancers are a worldwide problem among women. Recently, molecular targeted therapy opened up an avenue for cancer diagnosis and treatment. Long non-coding RNAs (lncRNAs) are RNA molecules (> 200 nt) that are not translated into protein, and interact with DNA, RNA, and proteins. LncRNAs were found to play pivotal roles in cancer tumorigenesis and progression. Nuclear paraspeckle assembly transcript 1 (NEAT1) is a lncRNA that mediates cell proliferation, migration, and EMT in gynecologic cancers by targeting several miRNAs/mRNA axes. Therefore, NEAT1 may function as a potent biomarker for the prediction and treatment of breast, ovarian, cervical, and endometrial cancers. In this narrative review, we summarized various NEAT1-related signaling pathways that are critical in gynecologic cancers. Long non-coding RNA (lncRNA) by targeting various signaling pathways involved in its target genes can regulate the occurrence of gynecologic cancers.

An updated review of contribution of long noncoding RNA-NEAT1 to the progression of human cancers

Long non-coding RNAs (lncRNAs) present pivotal roles in cancer tumorigenesis and progression. Recently, nuclear paraspeckle assembly transcript 1 (NEAT1) as a lncRNA has been shown to mediate cell proliferation, migration, and EMT in tumor cells. NEAT1 by targeting several miRNAs/mRNA axes could regulate cancer cell behavior. Therefore, NEAT1 may function as a potent biomarker for the prediction and treatment of some human cancers. In this review, we summarized various NEAT1-related signaling pathways that are critical in cancer initiation and progression.

Lnc-ing epigenetic mechanisms with autophagy and cancer drug resistance

Long noncoding RNAs (lncRNAs) comprise a diverse class of RNA molecules that regulate various physiological processes and have been reported to be involved in several human pathologies ranging from neurodegenerative disease to cancer. Therapeutic resistance is a major hurdle for cancer treatment. Over the past decade, several studies has emerged on the role of lncRNAs in cancer drug resistance and many trials have been conducted employing them. LncRNAs also regulate different cell death pathways thereby maintaining a fine balance of cell survival and death. Autophagy is a complex cell-killing mechanism that has both cytoprotective and cytotoxic roles. Similarly, autophagy can lead to the induction of both chemosensitization and chemoresistance in cancer cells upon therapeutic intervention. Recently the role of lncRNAs in the regulation of autophagy has also surfaced. Thus, lncRNAs can be used in cancer therapeutics to alleviate the challenges of chemoresistance by targeting the autophagosomal axis. In this chapter, we discuss about the role of lncRNAs in autophagy-mediated cancer drug resistance and its implication in targeted cancer therapy.

circRNA circSnx12 confers Cisplatin chemoresistance to ovarian cancer by inhibiting ferroptosis through a miR-194-5p/SLC7A11 axis

Ovarian cancer (OC) is the most common gynecological malignancy worldwide, and chemoresistance occurs in most patients, resulting in treatment failure. A better understanding of the molecular processes underlying drug resistance is crucial for development of efficient therapies to improve OC patient outcomes. Circular RNAs (circRNAs) and ferroptosis play crucial roles in tumorigenesis and resistance to chemotherapy. However, little is known about the role(s) of circRNAs in regulating ferroptosis in OC. To gain insights into cisplatin resistance in OC, we studied the ferroptosis-associated circRNA circSnx12. We evaluated circSnx12 expression in OC cell lines and tissues that were susceptible or resistant to cisplatin using quantitative real-time PCR. We also conducted in vitro and in vivo assays examining the function and mechanism of lnc-LBCSs. Knockdown of circSnx12 rendered cisplatin-resistant OC cells more sensitive to cisplatin in vitro and in vivo by activating ferroptosis, which was at least partially abolished by downregulation of miR-194-5p. Molecular mechanics studies indicate that circSnx12 can be a molecular sponge of miR-194-5p, which targets SLC7A11. According to our findings, circSnx12 ameliorates cisplatin resistance by blocking ferroptosis via a miR-194-5p/SLC7A11 pathway. CircARNT2 may thus serve as an effective therapeutic target for overcoming cisplatin resistance in OC. [BMB Reports 2023; 56(3): 184-189].

Extracellular vesicles derived from M2-polarized tumor-associated macrophages promote immune escape in ovarian cancer through NEAT1/miR-101-3p/ZEB1/PD-L1 axis

Evidence has been presented demonstrating that CD8⁺ T cells confer anti-cancer effects, which offers a promising approach to enhance immunotherapy. M2-polarized tumor-associated macrophages (TAMs) could transfer RNA to cancer cells by secreting extracellular vesicles (EVs) and stimulate immune escape of cancer cells. Thus, the current study aimed at exploring how EVs derived from M2-polarized TAMs (M2-TAMs) affected the proliferation of ovarian cancer (OC) cells and apoptosis of CD8⁺ T cells. M2-TAMs were observed in OC tissues, which promoted proliferation of OC cells and CD8⁺ T cell apoptosis by secreting EVs. OC-associated differentially expressed gene NEAT1 was screened by bioinformatics analysis. The in vitro and in vivo effects of TAM-EVs-NEAT1 and its regulatory mechanism were assessed using gain- and loss-of-function assays in co-culture systems of TAMs-derived EVs, OC cells, and CD8⁺ T cells and in tumor-bearing mice. NEAT1 was highly expressed in M2-derived EVs and OC cells co-cultured with M2-derived EVs. NEAT1 sponged miR-101-3p to increase ZEB1 and PD-L1 expression. In vitro and in vivo assays confirmed the tumor-supporting effects of NEAT1 delivered by M2-derived EVs on OC cell proliferation and CD8⁺ T cell apoptosis as well as tumor growth. Collectively, M2-derived EVs containing NEAT1 exerted a tumor-promoting role in OC via the miR-101-3p/ZEB1/PD-L1 axis.

circRNA circSnx12 confers Cisplatin chemoresistance to ovarian cancer by inhibiting ferroptosis through a miR-194-5p/SLC7A11 axis

Ovarian cancer (OC) is the most common gynecological malignancy worldwide, and chemoresistance occurs in most patients, resulting in treatment failure. A better understanding of the molecular processes underlying drug resistance is crucial for development of efficient therapies to improve OC patient outcomes. Circular RNAs (circRNAs) and ferroptosis play crucial roles in tumorigenesis and resistance to chemotherapy. However, little is known about the role(s) of circRNAs in regulating ferroptosis in OC. To gain insights into cisplatin resistance in OC, we studied the ferroptosis-associated circRNA circSnx12. We evaluated circSnx12 expression in OC cell lines and tissues that were susceptible or resistant to cisplatin using quantitative real-time PCR. We also conducted in vitro and in vivo assays examining the function and mechanism of lnc-LBCSs. Knockdown of circSnx12 rendered cisplatin-resistant OC cells more sensitive to cisplatin in vitro and in vivo by activating ferroptosis, which was at least partially abolished by downregulation of miR-194-5p. Molecular mechanics studies indicate that circSnx12 can be a molecular sponge of miR-194-5p, which targets SLC7A11. According to our findings, circSnx12 ameliorates cisplatin resistance by blocking ferroptosis via a miR-194-5p/SLC7A11 pathway. CircARNT2 may thus serve as an effective therapeutic target for overcoming cisplatin resistance in OC. [BMB Reports 2023; 56(3): 184-189].

Functions and mechanisms of lncRNA MALAT1 in cancer chemotherapy resistance

Chemotherapy is one of the most important treatments for cancer therapy. However, chemotherapy resistance is a big challenge in cancer treatment. Due to chemotherapy resistance, drugs become less effective or no longer effective at all. In recent years, long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been found to be associated with the development of chemotherapy resistance, suggesting that MALAT1 may be an important target to overcome chemotherapy resistance. In this review, we introduced the main mechanisms of chemotherapy resistance associated with MALAT1, which may provide new approaches for cancer treatment.

Long noncoding RNA RFPL1S-202 inhibits ovarian cancer progression by downregulating the IFN-β/STAT1 signaling

BACKGROUND

RFPL1S was first identified as one of the pseudogenes located in the intrachromosomal duplications within 22q12-13. Our previous study found that one of the predicted transcripts of lncRNA RFPL1S, ENST00000419368.1 (GRCh37/hg19), also named as RFPL1S-202 in Ensembl website, is significantly downregulated in the chemoresistant ovarian cancer cells. However, its function and underlying mechanism have not been studied.

METHODS

Quantitative Real-time PCR was used to analyze the expression. Cell Counting Kit-8, transwell, flow cytometry analysis and tail vein injected mouse model were used to test the function. RNA-sequencing, RNA pull down, western blot, ELISA and RNA-Binding Protein Immunoprecipitation were performed for studying the mechanism. 5' and 3' rapid amplification of complementary DNA ends were performed to analyze the full length of RFPL1S-202.

RESULTS

RFPL1S-202 is significantly downregulated in epithelial ovarian cancer tissues and cell lines. Gain- and loss-of-function study indicated that RFPL1S-202 could enhance cisplatin or paclitaxel in cytotoxicity, inhibit cell proliferation, invasion and migration of ovarian cancer cells in vitro, and inhibit the liver metastasis of ovarian cancer cells in vivo. Mechanistically, RFPL1S-202 could physically interact with DEAD-Box Helicase 3 X-linked (DDX3X) protein, and decrease the expression of p-STAT1 and the IFN inducible genes by increasing the m6A modification of IFNB1. RFPL1S-202 is a spliced and polyadenylated non-coding RNA with a full length of 1071 bp.

CONCLUSIONS

Our study suggested that the predicted lncRNA RFPL1S-202 exerts a tumor- suppressive function in oarian cancer chemoresistance and progression by interacting with DDX3X and down-regulating the IFN-β-STAT1 signaling pathway.

DNA methylation and transcriptomic features are preserved throughout disease recurrence and chemoresistance in high grade serous ovarian cancers

Background

Little is known about the role of global DNA methylation in recurrence and chemoresistance of high grade serous ovarian cancer (HGSOC).

Methods

We performed whole genome bisulfite sequencing and transcriptome sequencing in 62 primary and recurrent tumors from 28 patients with stage III/IV HGSOC, of which 11 patients carried germline, pathogenic BRCA1 and/or BRCA2 mutations.

Results

Landscapes of genome-wide methylation (on average 24.2 million CpGs per tumor) and transcriptomes in primary and recurrent tumors showed extensive heterogeneity between patients but were highly preserved in tumors from the same patient. We identified significant differences in the burden of differentially methylated regions (DMRs) in tumors from BRCA1/2 compared to non-BRCA1/2 carriers (mean 659 DMRs and 388 DMRs in paired comparisons respectively). We identified overexpression of immune pathways in BRCA1/2 carriers compared to non-carriers, implicating an increased immune response in improved survival (P = 0.006) in these BRCA1/2 carriers.

Conclusion

These findings indicate methylome and gene expression programs established in the primary tumor are conserved throughout disease progression, even after extensive chemotherapy treatment, and that changes in methylation and gene expression are unlikely to serve as drivers for chemoresistance in HGSOC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02440-z.

miRNA let-7 family regulated by NEAT1 and ARID3A/NF-κB inhibits PRRSV-2 replication in vitro and in vivo

Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically devastating diseases affecting the swine industry worldwide. To investigate the role of miRNAs in the infection and susceptibility of PRRS virus (PRRSV), twenty-four miRNA libraries were constructed and sequenced from PRRSV-infected and mock-infected Porcine alveolar macrophages (PAMs) of Meishan, Landrace, Pietrain and Qingping pigs at 9 hours post infection (hpi), 36 hpi, and 60 hpi. The let-7 family miRNAs were significantly differentially expressed between PRRSV-infected and mock-infected PAMs from 4 pig breeds. The let-7 family miRNAs could significantly inhibit PRRSV-2 replication by directly targeting the 3’UTR of the PRRSV-2 genome and porcine IL6, which plays an important role in PRRSV replication and lung injury. NEAT1 acts as a competing endogenous lncRNA (ceRNA) to upregulate IL6 by attaching let-7 in PAMs. EMSA and ChIP results confirmed that ARID3A could bind to the promoter region of pri-let-7a/let-7f/let-7d gene cluster and inhibit the expression of the let-7 family. Moreover, the NF-κB signaling pathway inhibits the expression of the let-7 family by affecting the nuclear import of ARID3A. The pEGFP-N1-let-7 significantly reduced viral infections and pathological changes in PRRSV-infected piglets. Taken together, NEAT1/ARID3A/let-7/IL6 play significant roles in PRRSV-2 infection and may be promising therapeutic targets for PRRS.

There are significant differences in susceptibility/resistance to PRRSV among different pig breeds. Especially the local pig breeds in China had strong resistance to PRRSV. However, due to the complexity of the interaction mechanism between pigs and PRRSV, the genetic mechanism leading to PRRSV susceptibility/resistance in different pig breeds is still unclear. MiRNAs play a vital regulatory role in immune response and development of PRRS. In this study, we found that the expression of miRNA let-7 family members were significantly different in PRRSV-infected/mock-infected PAMs from Pietrain, Qingping, Meishan, and Landrace pigs. Our findings illustrated that NEAT1/ARID3A/let-7/IL6 had a significant role in PRRSV-2 infection. What’s more, let-7 family could significantly reduce PRRSV infection and pathological changes in vitro and in vivo. This discovery provided a new idea for breeding PRRSV resistant pigs by revealing the molecular mechanism of PRRSV susceptibility in different pig breeds. Altogether, let-7 family have significant roles in PRRSV infection and may be promising therapeutic targets for PRRS.

The Long and the Short of It: NEAT1 and Cancer Cell Metabolism

Simple Summary

Altered metabolism is a hallmark of most cancers. The way that cancer cells regulate their energy production to fuel constant proliferation has been of interest with the hope that it may be exploited therapeutically. The long noncoding RNA, NEAT1, is often dysregulated in tumours. NEAT1 RNA can be transcribed as two isoforms with different lengths, with each variant responsible for different functions. This review explores how the isoforms contribute to cancer metabolism.

Abstract

The long noncoding RNA NEAT1 is known to be heavily dysregulated in many cancers. A single exon gene produces two isoforms, NEAT1_1 and NEAT1_2, through alternative 3′-end processing. As the longer isoform, NEAT1_2 is an essential scaffold for nuclear paraspeckle formation. It was previously thought that the short NEAT1_1 isoform only exists to keep the NEAT1 locus active for rapid paraspeckle formation. However, a recent glycolysis-enhancing function for NEAT1_1, contributing to cancer cell proliferation and the Warburg effect, has been demonstrated. Previous studies have mainly focused on quantifying total NEAT1 and NEAT1_2 expression levels. However, in light of the NEAT1_1 role in cancer cell metabolism, the contribution from specific NEAT1 isoforms is no longer clear. Here, the roles of NEAT1_1 and NEAT1_2 in metabolism and cancer progression are discussed.

The Emerging role of EMT-related lncRNAs in therapy resistance and their application as biomarkers

Cancer is the world's second largest cause of death. The most common cancer treatments are surgery, radiation therapy, and chemotherapy. Drug resistance, epithelial-to-mesenchymal transition (EMT), and metastasis are all pressing issues in cancer therapy today. Increasing evidence showed that drug-resistant and EMT are co-related with each other. Indeed, drug-resistant cancer cells possess enhanced EMT and invasive ability. Recent researches have demonstrated lncRNAs (long noncoding RNAs) are noncoding transcripts, which play an important role in the regulation of EMT, metastasis, and drug resistance in different cancers. However, the relationships among lncRNAs, EMT, and drug resistance are still unclear. These effects could be exerted via several signaling pathways such as TGF-β, PI3K-AKT, and Wnt/β-catenin. Identifying the crucial regulatory roles of lncRNAs in these pathways and processes leads to the development of novel targeted therapies. We review the key aspects of lncRNAs associated with EMT and therapy resistance. We focus on the crosstalk between lncRNAs and molecular signaling pathways affecting EMT and drug resistance. Moreover, each of the mentioned lncRNAs could be used as a potential diagnostic, prognostic, and therapeutic biomarker for cancer. Although, there are still many challenges to investigate lncRNAs for clinical applications.

LINC00174 Suppresses Non-Small Cell Lung Cancer Progression by Up-Regulating LATS2 via Sponging miR-31-5p

Objective

Dysregulation of long non-coding RNAs (lncRNAs) is associated with the progression of non-small cell lung cancer (NSCLC). This study aimed to investigate the role of long intergenic non-protein coding RNA 174 (LINC00174) in NSCLC.

Materials and Methods

In this experimental study, LINC00174 expression in NSCLC tissues and cell lines was investigated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Besides, cell counting kit-8 (CCK-8), 5-bromo-2'-deoxyuridine (BrdU). Transwell and Flow Cytometry assays were applied to detect the regulatory function of LINC00174 on the growth, migration and apoptosis of NSCLC cells. Bioinformatics analysis, dual luciferase reporter gene assay and RNA immunoprecipitation (RIP) assay predicted and verified the targeting relationship between LINC00174 and miR-31-5p, and between miR-31-5p and the 3´-untranslated region (3´UTR) of large tumor suppressor kinase 2 (LATS2), respectively. Western blotting was performed to detect the regulatory function of LINC00174 and miR-31-5p on LATS2 protein expression.

Results

Compared with that in normal lung tissues, LINC00174 expression in NSCLC tissues and cell lines was reduced. LINC00174 expression was negatively associated with the TNM stage of the patients. Functional experiments showed that LINC00174 overexpression inhibited NSCLC cell multiplication and migration, and induced apoptosis. Furthermore, LINC00174 targeted miR-31-5p and repressed its expression. Additionally, LINC00174 upregulated LATS2 expression through competitively binding to miR-31-5p.

Conclusion

LINC00174, as a competitive endogenous RNA, elevates LATS2 expression by adsorbing miR-31-5p, thereby inhibiting the viability and migration of NSCLC cells, and promoting apoptosis.

LncRNA NEAT1 ameliorate ischemic stroke via promoting Mfn2 expression through binding to Nova and activates Sirt3

BACKGROUND

Recent studies revealed that long non-coding RNAs (lncRNAs) have significant roles in regulating the pathogenesis of ischemia stroke, and oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell apoptosis. Aberrant expression of NEAT1 was found after the injury of ischemia-reperfusion, but the mechanism was not fully understood.

METHODS

The expression of NEAT1 and Mfn2 were detected in BV-2 and N2a cell with or without OGD/R-induced by qRT-PCR. Inflammatory cytokines secretion was detected by enzyme-linked immunosorbent assay (ELISA). The oxidative stress was evaluated by the examination of ROS, MDA and SOD levels. Flow cytometry and apoptosis marker detection by western blot were performed to examined apoptosis.

RESULTS

The expression of NEAT1 and Mfn2 were decreased in OGD/R-induced cell model. Overexpression of NEAT1 or Mfn2 reduced oxidative stress and apoptosis by OGD/R-induced in neuronal cells, while knockdown of Sirt3 reversed the protective effect of NEAT1 and Mfn2. NEAT1 stabilized Mfn2 mRNA via recruiting Nova. NEAT1 alleviates the oxidative stress and apoptosis by OGD/R-induced via activating Sirt3.

CONCLUSION

LncRNA NEAT1 stabilizes Mfn2 mRNA via recruiting Nova, therefore increase the expression of Mfn2 and alleviates ischemia-reperfusion induced oxidative stress and apoptosis via Mfn2/Sirt3 pathway.

Recent advances of NEAT1-miRNA interactions in cancer

With high incidence rate, cancer is the main cause of death in humans. Non-coding RNAs, as novel master regulators, especially long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), play important roles in the regulation of tumorigenesis. lncRNA NEAT1 has recently gained much attention, as it is dysregulated in a broad spectrum of cancers, where it acts as either an oncogene or a tumor suppressor gene. Accumulating evidence shows that NEAT1 is correlated with the process of carcinogenesis, including proliferation, invasion, survival, drug resistance, and metastasis. NEAT1 is considered to be a biomarker and a novel therapeutic target for the diagnosis and prognosis of different cancer types. The mechanisms by which NEAT1 plays a critical role in cancers are mainly via interactions with miRNAs. NEAT1-miRNA regulatory networks play significant roles in tumorigenesis, which has attracted much attention from researchers around the world. In this review, we summarize the interaction of NEAT1 with miRNAs in the regulation of protein-coding genes in cancer. A better understanding of the NEAT1-miRNA interactions in cancer will help develop new diagnostic biomarkers and therapeutic approaches.

RP5-1148A21.3 (lncRP5) exerts oncogenic function in human ovarian carcinoma

Ovarian cancer (OC) is a fatal gynecological malignancy that is difficult to diagnose at early stages. Various long non-coding RNAs (lncRNAs) are aberrantly expressed in OC and exert regulatory effects on OC; however, the underlying mechanism requires in-depth investigation. This work is designed to explore the molecular regulatory axis of a newly identified lncRNA in OC, that is, lncRNA RP5-1148A21.3 (lncRP5). RT-qPCR shows lncRP5 is significantly upregulated in OC patients and cell lines, and it is mainly located in the cytoplasm of OC cells. The results of CCK-8, colony formation, and transwell assays demonstrate that overexpression of lncRP5 greatly contributes to malignant behaviors of OC cells, while inhibition of lncRP5 shows the opposite effects. Moreover, the binding relationship between lncRP5 and miR-545-5p is predicted by bioinformatics and is further verified by luciferase assay. Functionally, the regulatory effects of lncRP5 and miR-545-3p are negatively related; miR-545-5p serves as a tumor suppressor in OC. Further studies demonstrate that PTP4A1 is the target gene of miR-545-5p. Overexpression of PTP4A1 abrogates the inhibitory function of miR-545-5p on OC cell growth and metastasis. The lncRP5/miR-545-5p/PTP4A1 axis is subsequently demonstrated in vivo, and knockdown of lncRP5 notably inhibits tumor growth. This study provides a novel regulatory mechanism of OC, which may contribute to the diagnosis and therapy of OC.

Function of BCLAF1 in human disease

Originally identified as a regulator of apoptosis and transcription, B-cell lymphoma-2-associated transcription factor 1 (BCLAF1) has since been shown to be associated with a multitude of biological processes, such as DNA damage response, splicing and processing of pre-mRNA, T-cell activation, lung development, muscle cell proliferation and differentiation, autophagy, ischemia-reperfusion injury, and viral infection. In recent years, an increasing amount of evidence has shown that BCLAF1 acts as either a tumor promoter or tumor suppressor in tumorigenesis depending on the cellular context and the type of cancer. Even in the same tumor type, BCLAF1 may have opposite effects. In the present review, the subcellular localization, structural features, mutations within BCLAF1 will be described, then the regulation of BCLAF1 and its downstream targets will be analyzed. Furthermore, the different roles and possible mechanisms of BCLAF1 in tumorigenesis will also be highlighted and discussed. Finally, BCLAF1 may be considered as a potential target for cancer therapy in the future.

LncRNA NORAD facilitates oral squamous cell carcinoma progression by sponging miR-577 to enhance TPM4

BACKGROUND

Long non-coding RNAs (lncRNAs) have been reported to be vital factors to affect the expression of genes and proteins. Also, it has been proved that the abnormal expression or mutation of lncRNAs stands as a signal of metastasis and proliferation of cancer. Nevertheless, the majority of lncRNAs still need to be explored in abundant cancers especially in oral squamous cell carcinoma (OSCC).

METHODS

RT-qPCR assays were applied to test the expression of RNAs. Mechanism assays were performed to verify the combination among NORAD, TPM4 and miR-577. Also, functional assays were conducted to verify the function of RNAs on OSCC cells.

RESULTS

LncRNA NORAD was highly expressed in OSCC tissues and cells. NORAD silencing repressed the biological behaviors of OSCC cells. MiR-577 was found in OSCC with low expression, and RIP assays illustrated that NORAD, miR-577 and TPM4 coexisted in RNA-induced silencing complexes. Rescue assays proved that the overexpression of TPM4 could recover the effect of NORAD silencing on OSCC progression.

CONCLUSIONS

It was revealed that NORAD functioned as a tumor promoter to sponge miR-577 thus elevating TPM4 in OSCC, which indicated that NORAD was worthy to be studied as a target for the treatment of OSCC.

Noncoding RNAs Interplay in Ovarian Cancer Therapy and Drug Resistance

Noncoding RNAs (ncRNAs) are several types of RNA that do not encode proteins, but are essential for cell regulation. Ovarian cancer (OC) is a type of gynecological cancer with a high mortality rate and a 5-year prognosis. OC is becoming more common with each passing year, and the symptoms of early-stage OC are sometimes undetectable. Meanwhile, early-stage OC has no symptoms and is difficult to diagnose. Because ncRNA has been shown to affect the development of OC and is widely distributed, it could be employed as a new biomarker for early OC. Furthermore, ncRNA has the potential to promote or inhibit drug resistance in OC, potentially giving a solution to multiple drug resistance. Various prior studies have found that different ncRNAs perform differently in OC. This article examines how mainstream ncRNAs have been expressed in OC in recent years, as well as their function in tumor growth.

LncRNA NEAT1 Promotes the Malignant Progression of Colorectal Cancer by Targeting ZEB1 via miR-448

Background: Long noncoding RNAs have been associated with various types of malignant tumors; however, the specific role of long noncoding RNAs in tumorigenesis still remains unclear in colorectal cancer. Here, we aim to elucidate the role of long noncoding RNA nuclear paraspeckle assembly transcript 1 in the malignant progression of colorectal cancer and investigate its underlying mechanisms. Methods: Real-time polymerase chain reaction was used to detect the expression of nuclear paraspeckle assembly transcript 1 in colorectal cancer tissues and cells. Cell Counting Kit-8 assay was used to determine the effect of nuclear paraspeckle assembly transcript 1 in proliferation. Transwell assay was used to explore the role of nuclear paraspeckle assembly transcript 1 in metastasis. Bioinformatics method was used to predict the core nuclear paraspeckle assembly transcript 1 interaction network. Real-time polymerase chain reaction was used to detect nuclear paraspeckle assembly transcript 1 and miR-448 expression levels. Western blotting was used to detect the expression levels of ZEB1. Luciferase assay was used to verify the relationship among nuclear paraspeckle assembly transcript 1, miR-448, and ZEB1. The effect of nuclear paraspeckle assembly transcript 1 on tumor growth was detected by tumorigenesis test in nude mice. Results: Long noncoding RNA–nuclear paraspeckle assembly transcript 1 was up-regulated in colorectal cancer tissues and cells. Knocking down of nuclear paraspeckle assembly transcript 1 can suppress colorectal cancer proliferation and invasion, and caused a reduction of ZEB1 expression and an increase of miR-448 expression. Furthermore, knockdown of nuclear paraspeckle assembly transcript 1 regulated miR-448/ZEB1 axis to inhibit the expression of ZEB1. miR-448 silencing can reverse the effect of nuclear paraspeckle assembly transcript 1 knockdown. Conclusion: Our result demonstrated that long noncoding RNA nuclear paraspeckle assembly transcript 1 promotes proliferation and invasion of colorectal cancer by targeting miR-448 to promote the expression of ZEB1, which may play a significant role in the tumorigenesis of colorectal cancer.

Long non-coding RNAs and their potential impact on diagnosis, prognosis, and therapy in prostate cancer: racial, ethnic, and geographical considerations

INTRODUCTION

Advances in high-throughput sequencing have greatly advanced our understanding of long non-coding RNAs (lncRNAs) in a relatively short period of time. This has expanded our knowledge of cancer, particularly how lncRNAs drive many important cancer phenotypes via their regulation of gene expression.

AREAS COVERED

Men of African descent are disproportionately affected by PC in terms of incidence, morbidity, and mortality. LncRNAs could serve as biomarkers to differentiate low-risk from high-risk diseases. Additionally, they may represent therapeutic targets for advanced and castrate-resistant cancer. We review current research surrounding lncRNAs and their association with PC. We discuss how lncRNAs can provide new insights and diagnostic biomarkers for African American men. Finally, we review advances in computational approaches that predict the regulatory effects of lncRNAs in cancer.

EXPERT OPINION

PC diagnostic biomarkers that offer high specificity and sensitivity are urgently needed. PC specific lncRNAs are compelling as diagnostic biomarkers owing to their high tissue and tumor specificity and presence in bodily fluids. Recent studies indicate that PCA3 clinical utility might be restricted to men of European descent. Further work is required to develop lncRNA biomarkers tailored for men of African descent.

Knockdown of lncRNA NEAT1 suppresses proliferation and migration, and induces apoptosis of cervical cancer cells by regulating the miR‑377/FGFR1 axis

To investigate the role of NEAT1 and the microRNA (miR)-377/fibroblast growth factor receptor 1 (FGFR1) axis in cervical cancer (CC), the expression levels of NEAT1, FGFR1 and miR-377 were detected in CC tissues and cell lines. NEAT1 or FGFR1 was knocked down by transfection with short hairpin RNA (sh)-NEAT1 or sh-FGFR1, and miR-377 was overexpressed by transfection with miR-377 mimics in HeLa and C33A cells. Cell viability and migration were measured using MTT and Transwell assays, respectively. Cell apoptosis was determined by flow cytometry. A dual luciferase reporter assay was performed to confirm the presence of binding sites between miR-377 and FGFR1. The results revealed that the expression levels of NEAT1 and FGFR1 were significantly elevated, whereas miR-377 expression was markedly decreased in CC tissues and cell lines. In HeLa and C33A cells, after NEAT1 knockdown, miR-377 expression was increased, cell viability and migration were inhibited, and apoptosis was induced. Similarly, silencing FGFR1 inhibited cell viability and migration, and induced apoptosis of HeLa and C33A cells. A dual luciferase reporter gene assay verified a targeting relationship between NEAT1 and miR-377. Inhibition of miR-377 or overexpression of FGFR1 reversed the effects of NEAT1 knockdown on cell function in HeLa and C33A cells. Moreover, a dual luciferase reporter assay confirmed that FGFR1 was a direct target of miR-377. In conclusion, suppression of NEAT1 inhibited cell viability and migration, and promoted apoptosis of CC cells, and these effects were achieved through regulation of the miR-377/FGFR1 axis.

(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.

LncRNA HLA Complex Group 11 Knockdown Alleviates Cisplatin Resistance in Gastric Cancer by Targeting the miR-144-3p/UBE2D1 Axis

OBJECTIVE

Cisplatin (DDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). LncRNA noncoding RNA HLA complex group 11 (lncRNA HCG11) has been confirmed to promote GC progression. This study attempted to investigate the underlying molecular mechanism of HCG11 in DDP resistance of GC.

METHODS

qRT-PCR was performed to evaluate the expression of HCG11, microRNA-144-3p (miR-144-3p), and ubiquitin-conjugating enzyme E2 D1 (UBE2D1) in GC. The correlation between HCG11 and clinicopathological features of GC patients was assessed. DDP-resistant GC cells and their parental cells were cultured in different concentrations of DDP. The role of HCG11 for the viability and the half maximal inhibitory concentration (IC50) of DDP in DDP-resistant GC cells was determined by MTT assay. Then, the invasion of DDP-resistant GC cells was measured by transwell assay. Next, a dual-luciferase reporter assay was used to confirm the interactions among HCG11, miR-144-3p, and UBE2D1 in GC.

RESULTS

The expression of HCG11 and UBE2D1 was elevated in tumor tissues of GC patients, but miR-144-3p was declined. HCG11 expression was elevated in DDP-resistant GC patients and is strongly correlated with DDP sensitivity and World Health Organization grade in GC patients. HCG11 knockdown reduced the viability, IC50 of DDP, and invasion of DDP-resistant GC cells. Additionally, HCG11 targeted miR-144-3p and miR-144-3p further targeted UBE2D1. Feedback experiments indicated that low expression of miR-144-3p or overexpression of UBE2D1 mitigated the inhibitory effect of HCG11 depletion on DDP resistance of GC cells.

CONCLUSION

HCG11 knockdown attenuated DDP resistance of GC cells through via miR-144-3p/UBE2D1 axis, affording a novel therapeutic strategy for GC.

The Non-Coding RNAs Inducing Drug Resistance in Ovarian Cancer: A New Perspective for Understanding Drug Resistance

Ovarian cancer, a common malignant tumor, is one of the primary causes of cancer-related deaths in women. Systemic chemotherapy with platinum-based compounds or taxanes is the first-line treatment for ovarian cancer. However, resistance to these chemotherapeutic drugs worsens the prognosis. The underlying mechanism of chemotherapeutic resistance in ovarian cancer remains unclear. Non-coding RNAs, including long non-coding RNAs, microRNAs, and circular RNAs, have been implicated in the development of drug resistance. Abnormally expressed non-coding RNAs can promote ovarian cancer resistance by inducing apoptosis inhibition, protective autophagy, abnormal tumor cell proliferation, epithelial-mesenchymal transition, abnormal glycolysis, drug efflux, and cancer cell stemness. This review summarizes the role of non-coding RNAs in the development of chemotherapeutic resistance in ovarian cancer, including their mechanisms, targets, and potential signaling pathways. This will facilitate the development of novel chemotherapeutic agents that can target these non-coding RNAs and improve ovarian cancer treatment.

The Emerging Role of Non-coding RNAs in Drug Resistance of Ovarian Cancer

Ovarian cancer is one of the most common gynecological malignancies with highest mortality rate among all gynecological malignant tumors. Advanced ovarian cancer patients can obtain a survival benefit from chemotherapy, including platinum drugs and paclitaxel. In more recent years, the administration of poly-ADP ribose polymerase inhibitor to patients with BRCA mutations has significantly improved the progression-free survival of ovarian cancer patients. Nevertheless, primary drug resistance or the acquisition of drug resistance eventually leads to treatment failure and poor outcomes for ovarian cancer patients. The mechanism underlying drug resistance in ovarian cancer is complex and has not been fully elucidated. Interestingly, different non-coding RNAs (ncRNAs), such as circular RNAs, long non-coding RNAs and microRNAs, play a critical role in the development of ovarian cancer. Accumulating evidence has indicated that ncRNAs have important regulatory roles in ovarian cancer resistance to chemotherapy reagents and targeted therapy drugs. In this review, we systematically highlight the emerging roles and the regulatory mechanisms by which ncRNAs affect ovarian cancer chemoresistance. Additionally, we suggest that ncRNAs can be considered as potential diagnostic and prognostic biomarkers as well as novel therapeutic targets for ovarian cancer.

NEAT1 as a competing endogenous RNA in tumorigenesis of various cancers: Role, mechanism and therapeutic potential

The nuclear paraspeckle assembly transcript 1 (NEAT1) is a long non-coding RNA (lncRNA) that is upregulated in a variety of human cancer types. Increasing evidence has shown that the elevation of NEAT1 in cancer cells promotes cell growth, migration, and invasion and inhibits cell apoptosis. It is also known that lncRNAs act as a competing endogenous RNA (ceRNA) by sponging microRNAs (miRNAs) to alter the expression levels of their target genes in the development of cancers. Therefore, it is important to understand the molecular mechanisms underlying this observation. In this review, specific emphasis was placed on NEAT1's role in tumor development. We also summarize and discuss the feedback roles of NEAT1/miRNA/target network in the progression of various cancers. As our understanding of the role of NEAT1 during tumorigenesis improves, its therapeutic potential as a biomarker and/or target for cancer also becomes clearer.

Long non-coding RNA NEAT1 facilitates the growth, migration, and invasion of ovarian cancer cells via the let-7 g/MEST/ATGL axis

Background/Aim

Growing evidence indicates a significant role of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in ovarian cancer, a frequently occurring malignant tumor in women; however, the possible effects of an interplay of NEAT1 with microRNA (miRNA or miR) let-7 g in ovarian cancer are not known. The current study aimed to investigate the role of the NEAT1/let-7 g axis in the growth, migration, and invasion of ovarian cancer cells and explore underlying mechanisms.

Methods

NEAT1 expression levels were examined in clinical tissue samples and cell lines. The relationships between NEAT1, let-7 g, and MEST were then analyzed. Gain- or loss-of-function approaches were used to manipulate NEAT1 and let-7 g. The effects of NEAT1 on cell proliferation, migration, invasion, and apoptosis were evaluated. Mouse xenograft models of ovarian cancer cells were established to verify the function of NEAT1 in vivo.

Results

NEAT1 expression was elevated while let-7 g was decreased in ovarian cancer clinical tissue samples and cell lines. A negative correlation existed between NEAT1 and let-7 g, whereby NEAT1 competitively bound to let-7 g and consequently down-regulate let-7 g expression. By this mechanism, the growth, migration, and invasion of ovarian cancer cells were stimulated. In addition, let-7 g targeted mesoderm specific transcript (MEST) and inhibited its expression, leading to promotion of adipose triglyceride lipase (ATGL) expression and inhibition of ovarian cancer cell growth, migration, and invasion. However, the effect of let-7 g was abolished by overexpression of MEST. Furthermore, silencing of NEAT1 decreased the xenograft tumor growth by decreasing MEST while up-regulating let-7 g and ATGL.

Conclusions

Cumulatively, the findings demonstrated that NEAT1 could promote malignant phenotypes of ovarian cancer cells by regulating the let-7 g/MEST/ATGL signaling axis. Therefore, NEAT1 can be regarded as an important molecular target and biomarker for ovarian cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02018-3.