H19 promotes endometrial cancer progression by modulating epithelial-mesenchymal transition

The Promotive and Inhibitory Role of Long Non-Coding RNAs in Endometrial Cancer Course-A Review

Endometrial cancer is one of the most common malignant tumours in women. The development of this tumour is associated with several genetic disorders, many of which are still unknown. One type of RNA molecules currently being intensively studied in many types of cancer are long non-coding RNAs (lncRNAs). LncRNA-coding genes occupy a large fraction of the human genome. LncRNAs regulate many aspects of cell development, metabolism, and other physiological processes. Diverse types of lncRNA can function as a tumour suppressor or an oncogene that can alter migration, invasion, cell proliferation, apoptosis, and immune system response. Recent studies suggest that selected lncRNAs are important in an endometrial cancer course. Our article describes over 70 lncRNAs involved in the development of endometrial cancer, which were studied via in vivo and in vitro research. It was proved that lncRNAs could both promote and inhibit the development of endometrial cancer. In the future, lncRNAs may become an important therapeutic target. The aim of this study is to review the role of lncRNAs in the development of carcinoma of uterine body.

Analysis of VEGF, IGF1/2 and the Long Noncoding RNA (lncRNA) H19 Expression in Polish Women with Endometriosis

The coordinated action of VEGF, IGF1/2 and H19 factors influences the development of endometriosis. The aim of this study was to analyze the expression level of these genes in patients with endometriosis. The study group consisted of 100 patients who were diagnosed with endometriosis on laparoscopic and pathological examination. The control group consisted of 100 patients who were found to be free of endometriosis during the surgical procedure and whose eutopic endometrium wasnormal on histopathological examination. These patients were operated on for uterine fibroids. Gene expression was determined by RT-PCR. The expression of the VEGF gene was significantly higher in the samples classified as clinical stage 1-2 compared to the control material (p < 0.05). There was also a statistically significant difference between the samples studied at clinical stages 1-2 and 3-4 (p < 0.01). The expression of the VEGF gene in the group classified as 1-2 was significantly higher. IGF1 gene expression was significantly lower both in the group of samples classified as clinical stages 1-2 and 3-4 compared to the control group (p < 0.05 in both cases). The expression of the H19 gene was significantly lower in the group of samples classified as clinical stage 3-4 compared to the control group (p < 0.01). The reported studies suggest significant roles of VEGF, IGF and H19 expression in the pathogenesis of endometriosis.

The emerging roles of long non-coding RNA (lncRNA) H19 in gynecologic cancers

Long non-coding RNA (lncRNA) H19 has gained significant recognition as a pivotal contributor to the initiation and advancement of gynecologic cancers, encompassing ovarian, endometrial, cervical, and breast cancers. H19 exhibits a complex array of mechanisms, demonstrating dualistic effects on tumorigenesis as it can function as both an oncogene and a tumor suppressor, contingent upon the specific context and type of cancer being investigated. In ovarian cancer, H19 promotes tumor growth, metastasis, and chemoresistance through modulation of key signaling pathways and interaction with microRNAs. Conversely, in endometrial cancer, H19 acts as a tumor suppressor by inhibiting proliferation, inducing apoptosis, and regulating epithelial-mesenchymal transition. Additionally, H19 has been implicated in cervical and breast cancers, where it influences cell proliferation, invasion, and immune evasion. Moreover, H19 has potential as a diagnostic and prognostic biomarker for gynecologic cancers, with its expression levels correlating with clinical parameters and patient outcomes. Understanding the functional roles of H19 in gynecologic cancers is crucial for the development of targeted therapeutic strategies and personalized treatment approaches. Further investigation into the intricate molecular mechanisms underlying H19's involvement in gynecologic malignancies is warranted to fully unravel its therapeutic potential and clinical implications. This review aims to elucidate the functional roles of H19 in various gynecologic malignancies.

H19: An Oncogenic Long Non-coding RNA in Colorectal Cancer

Colorectal cancer (CRC) has been recorded amongst the most common cancers in the world, with high morbidity and mortality rates, and relatively low survival rates. With risk factors such as chronic illness, age, and lifestyle associated with the development of CRC, the incidence of CRC is increasing each year. Thus, the discovery of novel biomarkers to improve the diagnosis and prognosis of CRC has become beneficial. Long non-coding RNAs (lncRNAs) have been emerging as potential players in several tumor types, one among them is the lncRNA H19. The paternally imprinted oncofetal gene is expressed in the embryo, downregulated at birth, and reappears in tumors. H19 aids in CRC cell growth, proliferation, invasion, and metastasis via various mechanisms of action, significantly through the lncRNA-microRNA (miRNA)-messenger RNA (mRNA)-competitive endogenous RNA (ceRNA) network, where H19 behaves as a miRNA sponge. The RNA transcript of H19 obtained from the first exon of the H19 gene, miRNA-675 also promotes CRC carcinogenesis. Overexpression of H19 in malignant tissues compared to adjacent non-malignant tissues marks H19 as an independent prognostic marker in CRC. Besides its prognostic value, H19 serves as a promising target for therapy in CRC treatment.

A novel epithelial-mesenchymal transition-related lncRNA signature predicts prognosis and immune status in endometrioid endometrial cancer

The pathogenesis and progression of endometrial cancer (EC) are associated with epithelial-mesenchymal transition (EMT) and long noncoding RNAs (lncRNAs). In the present study, we aimed to identify an EMT-related lncRNA signature and evaluate its prognostic value in EC. We obtained the expression profile of lncRNAs and clinical information of patients with endometrioid EC from The Cancer Genome Atlas database (N = 401). We identified a signature of 5 EMT-related lncRNAs and calculated the risk score of each patient. Next, we validated the independence of the prognostic value of the EMT-related lncRNA signature. Furthermore, we performed Gene Set Enrichment Analysis to identify potential molecular function and Kyoto Encyclopedia of Genes and Genomes pathways related to the EMT-related lncRNA signature. Tumor microenvironment analysis and immune checkpoint blockade (ICB) response prediction were also assessed. Survival analysis revealed that the high-risk group, based on the EMT-related lncRNA signature, had a poorer prognosis than the low-risk group in the training, testing, and entire sets. The predictive value of the EMT-related lncRNA signature was independent of age, The International Federation of Gynecology and Obstetrics stage, tumor grade, and body mass index. Time-dependent receiver operating characteristic curves also demonstrate the prognostic accuracy of this risk model. Gene Set Enrichment Analysis showed that cytokine-cytokine receptor interaction, glycolysis/gluconeogenesis, and IL-17 signaling pathway were significantly enriched. Furthermore, tumor microenvironment analysis indicated a significant negative correlation between the immune score and EMT-related lncRNA signature risks core, while the low-risk group was more likely to respond to ICB therapy than the high-risk group. A reliable EMT-related lncRNA signature of endometrioid EC was identified that could be utilized as an independent prognostic biomarker to predict patient survival outcomes and provide references for the option of ICB therapy.

Long non-coding RNA (lncRNA) H19 in human cancer: From proliferation and metastasis to therapy

Initiation and development of cancer depend on multiple factors that mutations in genes and epigenetic level can be considered as important drivers. Epigenetic factors include a large family of members and understanding their function in cancer has been a hot topic. LncRNAs are RNA molecules with no capacity in synthesis of proteins, and they have regulatory functions in cells. LncRNAs are localized in nucleus and cytoplasm, and their abnormal expression is related to development of tumor. This manuscript emphasizes on the role of lncRNA H19 in various cancers and its association with tumor hallmarks. The function of lncRNA H19 in most tumors is oncogenic and therefore, tumor cells increase its expression for promoting their progression. LncRNA H19 contributes to enhancing growth and cell cycle of cancers and by EMT induction, it is able to elevate metastasis rate. Silencing H19 induces apoptotic cell death and disrupts progression of tumors. LncRNA H19 triggers chemo- and radio-resistance in cancer cells. miRNAs are dually upregulated/down-regulated by lncRNA H19 in increasing tumor progression. Anti-cancer agents reduce lncRNA H19 in impairing tumor progression and increasing therapy sensitivity. A number of downstream targets and molecular pathways for lncRNA H19 have been detected in cancers including miRNAs, RUNX1, STAT3, β-catenin, Akt2 and FOXM1. Clinical studies have revealed potential of lncRNA H19 as biomarker and its association with poor prognosis. LncRNA H19 can be transferred to cancer cells via exosomes in enhancing their progression.

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.

Identifying immune subtypes of uterine corpus endometrial carcinoma and a four-paired-lncRNA signature with immune-related lncRNAs

Uterine corpus endometrial carcinoma (UCEC) is the third most frequent gynecological malignancies in the female reproductive system. Long non-coding RNAs (lncRNAs) are closely involved in tumor progression. This study aimed to develop an immune subtyping system and a prognostic model based on lncRNAs for UCEC. Paired lncRNAs and non-negative matrix factorization were applied to identify immune subtypes. Enrichment analysis was conducted to assess functional pathways, immune-related genes, and cells. Univariate and multivariate Cox regression analysis were performed to analyze the relation between lncRNAs and overall survival (OS). A prognostic model was constructed and optimized by least absolute shrinkage and selection operator (LASSO) and Akaike information criterion (AIC). Two immune subtypes (C1 and C2) and four paired-prognostic lncRNAs closely associated with overall survival were identified. Some immune features, sensitivity of chemotherapy and immunotherapy, and the relation with immune escape showed variations between two subtypes. A nomogram established based on prognostic model and clinical features was effective in OS prediction. The immune subtyping system based on lncRNAs and the four-paired-lncRNA signature was predictive of UCEC prognosis and can facilitate personalized therapies such as immunotherapy or RNA-based therapy for UCEC patients.

Towards Personalized Medicine: Non-Coding RNAs and Endometrial Cancer

Endometrial cancer (EC) is the most frequent female cancer associated with excellent prognosis if diagnosed at an early stage. The risk factors on which clinical staging is based are constantly updated and genetic and epigenetic characteristics have recently been emerging as prognostic markers. The evidence shows that non-coding RNAs (ncRNAs) play a fundamental role in various biological processes associated with the pathogenesis of EC and many of them also have a prognosis prediction function, of remarkable importance in defining the therapeutic and surveillance path of EC patients. Personalized medicine focuses on the continuous updating of risk factors that are identifiable early during the EC staging to tailor treatments to patients. This review aims to show a summary of the current classification systems and to encourage the integration of various risk factors, introducing the prognostic role of non-coding RNAs, to avoid aggressive therapies where not necessary and to treat and strictly monitor subjects at greater risk of relapse.

The role of epigenetic mechanisms in the regulation of gene expression in the cyclical endometrium

BACKGROUND

The human endometrium is a highly dynamic tissue whose function is mainly regulated by the ovarian steroid hormones estradiol and progesterone. The serum levels of these and other hormones are associated with three specific phases that compose the endometrial cycle: menstrual, proliferative, and secretory. Throughout this cycle, the endometrium exhibits different transcriptional networks according to the genes expressed in each phase. Epigenetic mechanisms are crucial in the fine-tuning of gene expression to generate such transcriptional networks. The present review aims to provide an overview of current research focused on the epigenetic mechanisms that regulate gene expression in the cyclical endometrium and discuss the technical and clinical perspectives regarding this topic.

MAIN BODY

The main epigenetic mechanisms reported are DNA methylation, histone post-translational modifications, and non-coding RNAs. These epigenetic mechanisms induce the expression of genes associated with transcriptional regulation, endometrial epithelial growth, angiogenesis, and stromal cell proliferation during the proliferative phase. During the secretory phase, epigenetic mechanisms promote the expression of genes associated with hormone response, insulin signaling, decidualization, and embryo implantation. Furthermore, the global content of specific epigenetic modifications and the gene expression of non-coding RNAs and epigenetic modifiers vary according to the menstrual cycle phase. In vitro and cell type-specific studies have demonstrated that epithelial and stromal cells undergo particular epigenetic changes that modulate their transcriptional networks to accomplish their function during decidualization and implantation.

CONCLUSION AND PERSPECTIVES

Epigenetic mechanisms are emerging as key players in regulating transcriptional networks associated with key processes and functions of the cyclical endometrium. Further studies using next-generation sequencing and single-cell technology are warranted to explore the role of other epigenetic mechanisms in each cell type that composes the endometrium throughout the menstrual cycle. The application of this knowledge will definitively provide essential information to understand the pathological mechanisms of endometrial diseases, such as endometriosis and endometrial cancer, and to identify potential therapeutic targets and improve women's health.

The long-noncoding RNA SOCS2-AS1 suppresses endometrial cancer progression by regulating AURKA degradation

Aberrant long-noncoding RNA (lncRNA) expression has been shown to be involved in the pathogenesis of endometrial cancer (EC). Herein, we report a novel tumor suppressor lncRNA SOCS2-AS1 in EC. Quantitative real-time PCR was performed to detect RNA expression. In situ hybridization and nuclear/cytoplasmic fractionation assays were used to detect the subcellular location. We found that SOCS2-AS1 was downregulated in EC tissues. Its reduced expression was correlated with advanced clinical stage and poor prognosis. Forced expression of SOCS2-AS1 suppressed EC cell proliferation and induced cell-cycle arrest and apoptosis. SOCS2-AS1-binding proteins were detected using RNA pull-down assay and mass spectrometry. Mechanistically, SOCS2-AS1 bound to Aurora kinase A (AURKA) and increased its degradation through the ubiquitin-proteasome pathway. In conclusion, SOCS2-AS1 may thus serve as a prognostic predictor and a biomarker for AURKA-inhibitor treatment in EC patients.

Long non-coding RNAs in endometrial physiology and pathophysiology

The endometrium is an essential component of the female uterus which provides the environment for pregnancy establishment and maintenance. Abnormalities of the endometrium not only lead to difficulties in establishing and maintaining pregnancy but also play a causative role in diseases of endometrial origin including endometriosis and endometrial cancer. Non-coding RNAs are proposed to play a role in regulating the genome in both normal endometrial physiology and pathophysiology. In this review, we first provide a general overview of non-coding RNAs and reproductive physiology of the endometrium. We then discuss the role on non-coding RNAs in normal endometrial physiology and pathophysiology of endometrial infertility. We then conclude with non-coding RNAs in the pathophysiology of endometriosis and endometrial cancer.

Non-Coding RNAs as Prognostic Markers for Endometrial Cancer

Endometrial cancer (EC) has been classified over the years, for prognostic and therapeutic purposes. In recent years, classification systems have been emerging not only based on EC clinical and pathological characteristics but also on its genetic and epigenetic features. Noncoding RNAs (ncRNAs) are emerging as promising markers in several cancer types, including EC, for which their prognostic value is currently under investigation and will likely integrate the present prognostic tools based on protein coding genes. This review aims to underline the importance of the genetic and epigenetic events in the EC tumorigenesis, by expounding upon the prognostic role of ncRNAs.

An association study of polymorphisms in the H19 imprinted gene in an Iranian population with the risk of polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies that causes problems in female fertility at the reproductive age. PCOS is a multifactorial disease, with genetic factors playing a crucial role in its development. H19 is a long non-coding RNA (lncRNA) expressed from the maternal chromosome, which is correlated with PCOS. In this study, 115 women suffering from PCOS and 130 healthy women with regular menstrual cycles were recruited as case and control groups, respectively. After the extraction of genomic DNA, the restriction fragment length polymorphism polymerase chain reaction was employed for genotyping of rs2067051G>A and rs3741219T>C. Statistical analysis was done using SPSS package V.22 for Windows. In silico analysis was recruited to determine the effects of SNPs on the secondary structure of gene transcript as well as miRNA binding sites. The obtained data showed that the A allele of rs2067051G>A was associated with the high risk of PCOS (OR = 2.00, 95%CI = 1.38-2.91, P = 0.00). AG and AA genotypes led to a 3.64- and (about) a five-fold increase in the risk of PCOS, respectively (95%CI = 2.02-6.54, P = 0.00, and 95%CI = 1.51-16.52, P = 0.00, respectively). These variants caused a significant increase in the risk of this disorder in all genotype models except in the recessive model. However, no association was found between rs3741219T>C and the increased risk of PCOS, either in the allele or in the genotype models. According to the findings, rs2067051G>A is associated with an increased risk of PCOS in the Iranian population.

Long noncoding RNA H19 acts as a miR-340-3p sponge to promote epithelial-mesenchymal transition by regulating YWHAZ expression in paclitaxel-resistant breast cancer cells

Breast cancer (BC) is the leading cause of cancer-related death in women worldwide and one of the most prevalent malignancy. In recent years, increasing evidence had illuminated that long noncoding RNAs (lncRNAs) serve as critical factors in multiple tumor progression, including BC. Emerging references had indicated that the lncRNA H19 acts as significant roles in tumor progression and epithelial-mesenchymal transition (EMT). However, the underlying molecular mechanisms and biological roles of H19 in BC invasion, metastasis and EMT are still unclear. In this study, it was detected that the expression level of H19 was increased in BC paclitaxel-resistant (PR) cells subline (MCF-7/PR) in comparison with MCF-7 parental cells. In vitro, there were demonstrated that H19 overexpression promoted BC cells proliferation, metastasis, invasion and EMT procedures, and suppressed cells apoptosis. Whereas, H19 suppression resulted in the contrary biological effects. Besides, bioinformatics tools and dual-luciferase reporters assays indicated that miR-340-3p could act as a potential target gene of H19, the underlying mechanism studies proved that H19 could act as a competing endogenous RNA (ceRNA) via competitively binding miR-340-3p to promote BC cell proliferation, metastasis and EMT by regulating tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) and potentiate the Wnt/β-catenin signaling in BC cells. In summary, our findings demonstrated that H19 could act as a ceRNA in BC progression, metastasis and EMT through modulating miR-340-3p/YWHAZ axis and activating the canonical Wnt/β-catenin signaling pathway, indicating that H19 might act as an underlying therapeutic target and prognostic biomarker for BC therapy.

The Interplay of Tumor Stroma and Translational Factors in Endometrial Cancer

Endometrial cancer (EC) is a common gynecologic malignancy which continues to have a poor prognosis in advanced stages due to current therapeutic limitations. A significant mechanism of chemoresistance in EC has been shown to also be the enhancement of epithelial to mesenchymal transition (EMT) and the subsequent obtainment of stem cell-like characteristics of EC. Current evidence on EMT in EC however fails to explain the relationship leading to an EMT signaling enhancement. Our review therefore focuses on understanding eukaryotic translation initiation factors (eIFs) as key regulators of the translational process in enhancing EMT and subsequently impacting higher chemoresistance of EC. We identified pathways connected to the development of a microenvironment for EMT, inducers of the process specifically related to estrogen receptors as well as their interplay with eIFs. In the future, investigation elucidating the translational biology of EC in EMT may therefore focus on the signaling between protein kinase RNA-like ER kinase (PERK) and eIF2alpha as well as eIF3B.

LncRNA TDRG1 Promotes Proliferation, Invasion and Epithelial-Mesenchymal Transformation of Osteosarcoma Through PI3K/AKT Signal Pathway

Objective

This study aimed to investigate the effect of long non-coding TDRG1 on proliferation and migration of osteosarcoma cells through PI3K/AKT signaling pathway.

Materials and Methods

Altogether 87 cases of osteosarcoma tissues and adjacent tissues were collected, and osteosarcoma cells and osteoblasts were purchased. The expression of LncRNA TDRG1 in tissues and cells was detected by RT-PCR. Si-NC, si-TDRG1, and Sh-TDRG1 were transfected into osteosarcoma cells. L740Y-P (activator of PI3K/AKT pathway) and LY294002 (inhibitor of PI3k/AKT pathway) were used to interfere with PI3k/Akt signaling pathway in osteosarcoma cells. qRT-PCR was used to detect the expression of TDRG1 in osteosarcoma tissues and cells. WB was used to detect the expression of p-PI3K, p-AKT, N-cadherin, E-Cadherin, vimentin, Bax, Caspase-3, and Bcl-2 in cells. CCK-8, Transwell and cell scratch tests were used to detect cell proliferation, invasion and migration, and flow cytometry was used to detect cell apoptosis.

Results

TDRG1 was highly expressed in osteosarcoma, and the levels of p-PI3K and p-AKT were also up-regulated. Cell experiments showed that inhibiting the expression of TDRG1 could inhibit the proliferation, invasion, migration and EMT of osteosarcoma cells, promote the apoptosis of cells, and up-regulating the expression of TDRG1 could promote the proliferation, invasion, migration and EMT of osteosarcoma cells and inhibit the apoptosis of cells. The 740Y-P intervention could reverse the inhibition of Si-TDRG1 on osteosarcoma cell proliferation, invasion, migration and EMT and the promotion of cell apoptosis. LY294002 intervention could reverse the promotion of Sh-TDRG1 on osteosarcoma cell proliferation, invasion, migration and EMT and the inhibition of cell apoptosis.

Conclusion

TDRG1 is highly expressed in osteosarcoma tissue. Silencing the expression of osteosarcoma can inhibit the proliferation, invasion, migration and EMT of osteosarcoma cells by inhibiting PI3K/AKT signaling pathway, which may be a new target for diagnosis and treatment of osteosarcoma.

H19 lncRNA: Roles in tumorigenesis

H19 is a long non-coding RNA [lncRNA] which was firstly described as an oncofetal transcript. The imprinted gene is normally expressed from the maternal allele. However, this pattern of imprinting is dysregulated in several cancers leading to aberrant up-regulation of H19 in malignant tissues. Several studies have utilized this aberrant expression pattern to find specific biomarkers for detection of cancer in tumoral tissues or peripheral blood. Moreover, single nucleotide polymorphisms within H19 have been associated with risk of oral squamous cell carcinoma, hepatocellular carcinoma, breast cancer, bladder cancer, gastric cancer and colorectal cancer. Taken together, H19 is regarded as a biomarker for cancer and a putative therapeutic target in these human disorders.

Knockdown of lncRNA TDRG1 Inhibits Tumorigenesis in Endometrial Carcinoma Through the PI3K/AKT/mTOR Pathway

BACKGROUND AND OBJECTIVE

Endometrial carcinoma (EC) is one of the most frequently diagnosed malignancies in females. Dysregulation of lncRNA TDRG1 has been widely documented in several cancers, including EC. However, the mechanism of this lncRNA involving in EC progression remains to be further elucidated.

MATERIALS AND METHODS

The enrichment levels of TDRG1 in EC tissues and cell lines were examined by RT-qPCR. Flow cytometry, cell counting kit-8 (CCK-8), transwell, and Western blot assays were conducted to assess whether TDRG1 knockdown could affect cell cycle arrest, proliferation, migration, invasion, and apoptosis of EC cells. The phosphorylation levels of mTOR, AKT and PI3K that associated with PI3K/Akt/mTOR pathway were determined by Western blot assay.

RESULTS

TDRG1 expression was markedly upregulated in EC tissues and cell lines. Knockdown of TDRG1 significantly induced cell cycle arrest and apoptosis, inhibited cell proliferation, restrained the invasion and migration abilities in EC cells. Moreover, TDRG1 silencing decreased the protein levels of p-AKT, p-PI3K, and p-mTOR of EC cells.

CONCLUSION

Our data underlined the implication of TDRG1 in EC progression, proposing that targeting TDRG1 might be a potential therapeutic avenue in EC.

The role of long non-coding RNA H19 in breast cancer

Breast cancer is the most common malignant tumor in women in the majority of countries, such as China, Britain and Australia, and its morbidity and mortality rates remain very high. Long non-coding RNAs (lncRNAs) are non-coding RNAs (ncRNAs) >200 nucleotides in length that lack open reading frames. LncRNA H19 is a transcription product of the H19 gene, and the aberrant expression of H19 can be demonstrated in various types of tumor cell. The purpose of the present review was to elaborate the role of H19 in breast cancer. H19 can regulate gene expression in breast cancer at multiple levels, including epigenetic, transcriptional and posttranscriptional. The abnormal expression of H19 is closely associated with the tumorigenesis and progression of breast cancer via different underlying molecular mechanisms, such as encoding microRNA-675, competing endogenous RNA regulation and interacting with MYC. A large number of clinical studies have suggested that H19 can serve as a potential biomarker for the diagnosis of breast cancer. High expression levels of H19 increases the drug resistance of breast cancer cells and is associated with poor prognosis within patients with breast cancer. Therefore, serum H19 levels may have momentous significance in the clinical setting.

Long non-coding RNAs and endometrial cancer

Endometrial cancer (EC) is one of the most common gynecologic malignancies. In spite of the advance in chemotherapy, radiotherapy or surgical techniques for EC in recent years, the survival rate of advanced stage EC patients remains unsatisfactory. Long non-coding RNAs (lncRNAs) are known as transcripts longer than 200 nucleotides exhibiting no or limited protein-coding potential. Growing evidence suggested lncRNAs may be a critical class of pervasive genes involved in cancer progression. However, the function and biological relevance between lncRNAs and EC remain not yet fully understood. Accumulating evidence has indicated that lncRNAs are dysregulated in EC, and closely related to tumorigenesis, metastasis and chemoresistance. In this review, we summarize the known regulation and functional roles of lncRNAs in EC. Besides, we will discuss the potential of lncRNAs as diagnostic biomarkers and therapeutic targets in EC.

Exploring lncRNA-Mediated Regulatory Networks in Endometrial Cancer Cells and the Tumor Microenvironment: Advances and Challenges

Recent studies have revealed both the promise and challenges of targeting long non-coding RNAs (lncRNAs) to diagnose and treat endometrial cancer (EC). LncRNAs are upregulated or downregulated in ECs compared to normal tissues and their dysregulation has been linked to tumor grade, FIGO stage, the depth of myometrial invasion, lymph node metastasis and patient survival. Tumor suppressive lncRNAs (GAS5, MEG3, FER1L4 and LINC00672) and oncogenic lncRNAs (CCAT2, BANCR, NEAT1, MALAT1, H19 and Linc-RoR) have been identified as upstream modulators or downstream effectors of major signaling pathways influencing EC metastasis, including the PTEN/PI3K/AKT/mTOR, RAS/RAF/MEK/ERK, WNT/β-catenin and p53 signaling pathways. TUG1 and TDRG1 stimulate the VEGF-A pathway. PCGEM1 is implicated in activating the JAK/STAT3 pathway. Here, we present an overview of the expression pattern, prognostic value, biological function of lncRNAs in EC cells and their roles within the tumor microenvironment, focusing on the influence of lncRNAs on established EC-relevant pathways. We also describe the emerging classification of EC subtypes based on their lncRNA signature and discuss the clinical implications of lncRNAs as valuable biomarkers for EC diagnosis and potential targets for EC treatment.

Long Non-Coding RNAs in Obesity-Induced Cancer

Many mechanisms of obesity-induced cancers have been proposed. However, it remains unclear whether or not long non-coding RNAs (lncRNAs) play any role in obesity-induced cancers. In this article, we briefly discuss the generally accepted hypotheses explaining the mechanisms of obesity-induced cancers, summarize the latest evidence for the expression of a number of well-known cancer-associated lncRNAs in obese subjects, and propose the potential contribution of lncRNAs to obesity-induced cancers. We hope this review can serve as an inspiration to scientists to further explore the regulatory roles of lncRNAs in the development of obesity-induced cancers. Those findings will be fundamental in the development of effective therapeutics or interventions to combat this life-threatening adverse effect of obesity.

Long non-coding RNAs as emerging regulators of epithelial to mesenchymal transition in gynecologic cancers

Gynecologic cancer is a vital global healthcare issue with high rates of mortality and morbidity. Tumor metastasis attributes to most of the death suffering from solid tumors. The epithelial-mesenchymal transition (EMT) plays a pivotal role in initiating metastasis. Long non-coding RNAs (lncRNAs), a well-known group of non-coding RNAs, and a prominent topic in life science research, are misregulated in many malignancies and some are EMT-associated. In the case of gynecologic cancers, several EMT-associated lncRNAs have been identified and found to be implicated in cancer aggressiveness and progression. Mechanically, these lncRNAs participate in the EMT-related metastatic process in multiple ways including interaction with polycomb repressive complex 2 (PRC2), regulation of EMT signaling networks, mediation of EMT-transcription factors (EMT-TFs) and EMT markers, and cooperation with microRNAs (miRNAs). Further studies on these EMT-associated lncRNAs and identification of more relevant lncRNAs are imperative for the lncRNAs-based clinical management of high rate of metastasis in patients with gynecologic cancers.

Non-Coding RNAs and Endometrial Cancer

Non-coding RNAs (ncRNAs) are involved in the regulation of cell metabolism and neoplastic transformation. Recent studies have tried to clarify the significance of these information carriers in the genesis and progression of various cancers and their use as biomarkers for the disease; possible targets for the inhibition of growth and invasion by the neoplastic cells have been suggested. The significance of ncRNAs in lung cancer, bladder cancer, kidney cancer, and melanoma has been amply investigated with important results. Recently, the role of long non-coding RNAs (lncRNAs) has also been included in cancer studies. Studies on the relation between endometrial cancer (EC) and ncRNAs, such as small ncRNAs or micro RNAs (miRNAs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), antisense RNAs (asRNAs), small nuclear RNAs (snRNAs), Piwi-interacting RNAs (piRNAs), small nucleolar RNAs (snoRNAs), competing endogenous RNAs (ceRNAs), lncRNAs, and long intergenic ncRNAs (lincRNAs) have been published. The recent literature produced in the last three years was extracted from PubMed by two independent readers, which was then selected for the possible relation between ncRNAs, oncogenesis in general, and EC in particular.

The silencing of LncRNA-H19 decreases chemoresistance of human glioma cells to temozolomide by suppressing epithelial-mesenchymal transition via the Wnt/β-Catenin pathway

Introduction

Temozolomide (TMZ) is commonly used for glioma chemotherapy. However, TMZ resistance limits the therapeutic effect of TMZ in glioma treatment. LncRNA-H19 acts as an oncogenic LncRNA in some types of cancers and has been reported to be up-regulated in glioma.

Materials and methods

In our present study, we established TMZ-resistant glioma cells (U-251TMZ and M059JTMZ) to explore the effect of H19 on the chemoresistance of glioma cells.

Results

We observed that the expression of H19 was significantly increased in U-251TMZ and M059JTMZ cells. Knockdown of H19 expression using specific shRNA in U-251TMZ and M059JTMZ led to decreased half maximal inhibitory concentration (IC₅₀) values for TMZ and increased cell apoptosis rates, indicating that the silencing of H19 decreased chemoresistance of glioma cells to TMZ. In addition, silencing of H19 suppressed epithelial-mesenchymal transition (EMT) by increasing the expression of epithelial marker E-cadherin and decreasing the expression of mesenchymal marker Vimentin and ZEB1. Moreover, inducing EMT by TGF-β1 treatment led to increased IC₅₀ values for TMZ and decreased cell apoptosis rates compared with TMZ+H19 shRNA group, suggesting that the induction of EMT counteracted the inhibitory effect of H19 shRNA on chemoresistance of glioma cells to TMZ. Furthermore, the reduced expression of H19 down-regulated the expression of β-Catenin and its downstream targets c-myc and Survivin in TMZ-treated glioma cells. Activation of Wnt/β-Catenin pathway by Licl treatment promoted EMT and enhanced chemoresistance to TMZ compared with TMZ+H19 shRNA group.

Conclusion

Taken together, our data suggest that H19 decreased chemoresistance of glioma cells to TMZ by suppressing EMT via the inhibition of Wnt/β-Catenin pathway. Our study might represent a novel therapeutic target for TMZ-resistant glioma.

Regulatory mechanisms of long noncoding RNAs on gene expression in cancers

Long non-coding RNAs (lncRNAs) are a heterogeneous class of RNAs that are non-protein coding transcripts longer than 200 nucleotides. In this review, we introduce the mechanisms by which lncRNAs regulate gene expression in four parts, epigenetic regulation (genetic imprinting and chromatin remodeling), transcriptional regulation (molecular decoy), post-transcriptional regulation (splicing and mRNA decay), and translational regulation. H19, Xist, and others are involved in genomic imprinting. HOTAIR and ANRIL function in chromatin remodeling. GAS5 is degraded through an RNA decay pathway. NEAT1 and MALAT1 function not only in the regulation of transcription but also in splicing.