LncRNA H19 Overexpression in Endometriosis and its Utility as a Novel Biomarker for Predicting Recurrence

Role of Molecular Biomarkers in Endometriosis-Related Infertility: A Narrative Review of the Literature

Endometriosis is a chronic benign inflammatory disease that affects women of reproductive age. The clinical presentations of endometriosis include dysmenorrhea, dyspareunia, chronic pelvic pain, and infertility. There is a well-established association between endometriosis and infertility. Therefore, there is a need for an early diagnosis of endometriosis-related infertility. In this study, we aim to identify the role of biomarkers as predictive factors of the presence of the disease and its severity and their correlation with the pregnancy outcome. We performed an electronic database search of all published studies in PubMed and EMBASE from January 2018 to May 2023. Numerous innovative biomarkers identified in cases of endometriosis and infertility have been studied over the past years, including micro-RNAs, BCL6 endometrial expression, cytotoxic T-lymphocyte antigen 4, human leukocyte antigen G, programmed cell death protein 1, programmed cell death ligand 1 immune checkpoint molecules, plasma fibronectin-fibrin complexes, homeobox A10 gene, systemic inflammatory response markers, uterine natural killer cells, and the eutopic endometrium proteome. Considerable research has been done to identify diagnostic biomarkers for the early detection and prevention of endometriosis-associated infertility. However, none of these biomarkers displayed enough diagnostic accuracy to be used in daily clinical practice. Future research is valuable to establish them as reliable diagnostic tools.

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.

Long non-coding RNAs and female infertility: What do we know?

Ten percent of people who are of reproductive age experience infertility. Sometimes the most effective therapies, including technology for assisted reproduction, may lead to unsuccessful implantation. Because of the anticipated epigenetic alterations of in vitro as well as in vitro fertilization growth of embryos, these fertility techniques have also been linked to unfavorable pregnancy outcomes linked to infertility. In this regard, a variety of non-coding RNAs such as long noncoding RNAs (lncRNAs) act as epigenetic regulators in the various physiological and pathophysiological events such as infertility. LncRNAs have been made up of cytoplasmic and nuclear nucleotides; RNA polymerase II transcribes these, which are lengthier than 200 nt. LncRNAs perform critical roles in a number of biological procedures like nuclear transport, X chromosome inactivation, apoptosis, stem cell pluripotency, as well as genomic imprinting. A significant amount of lncRNAs were linked into a variety of biological procedures as high throughput sequencing technology advances, including the development of the testes, preserving spermatogonial stem cells' capacity for differentiation along with self-renewal, and controlling spermatocyte meiosis. All of them point to possible utility of lncRNAs to be biomarkers and treatment aims for female infertility. Herein, we summarize various lncRNAs that are involved in female infertility.

Serum CA125 as a biomarker for dysmenorrhea in adenomyosis

OBJECTIVE

To explore the association between CA125 and dysmenorrhea in adenomyosis, and the factors affecting CA125 in adenomyosis.

METHODS

Patients were grouped a the presence of dysmenorrhea. The receiver operating characteristic (ROC) curve was applied to assess the utility of CA125 for dysmenorrhea. Binary logistic regression was employed to identify the factors associating dysmenorrhea and CA125 level.

RESULTS

Patients in the dysmenorrhea group had higher CA125 levels than those in the non-dysmenorrhea group. For those with dysmenorrhea, CA125 levels of diffuse subtype group were higher than those of the focal subtype group. The CA125 level of 35 U/mL was validated as the optimal cut-point for dysmenorrhea in ROC curves. Compared with patients whose CA125 was 35 U/mL or less, those with CA125 levels greater than 35 U/mL were more likely to have dysmenorrhea. Thereafter, the multiple regression analysis showed that adenomyotic lesion volume was positively correlated with CA125 level in the total cohort and subtype groups, while age was negatively correlated with CA125 level in the total cohort and diffuse subtype.

CONCLUSIONS

The pathogenesis of adenomyosis is not clear. CA125 was associated with dysmenorrhea in adenomyosis, and, furthermore, CA125 level is positively correlated with the severity of the disease.

The role of long non-coding RNA H19 in infertility

Infertility is defined as the failure to conceive after at least one year of unprotected intercourse. Long non-coding RNAs (lncRNAs) are transcripts that contain more than 200 nucleotides but do not convert into proteins. LncRNAs, particularly lncRNA H19, have been linked to the emergence and progression of various diseases. This review focuses on the role of H19 in infertility caused by polycystic ovary syndrome, endometriosis, uterine fibroids, diminished ovarian reserve, male factor, and assisted reproductive technology-related pathology, highlighting the potential of H19 as a molecular target for the future treatment of infertility.

A comprehensive overview of exosome lncRNAs: emerging biomarkers and potential therapeutics in endometriosis

Endometriosis is a gynecological condition that significantly impacting women's daily lives. In recent years, the incidence of endometriosis has been rising yearly and is now an essential contributor to female infertility. Exosomes are extracellular vesicles (EVs) that carry long noncoding RNA (lncRNA) and shield lncRNA from the outside environment thanks to their vesicle-like structure. The role of exosome-derived lncRNAs in endometriosis is also receiving more study as high-throughput sequencing technology develops. Several lncRNAs with variable expression may be crucial to the emergence and growth of endometriosis. The early diagnosis of endometriosis will be considerably improved by further high specificity and sensitivity Exosome lncRNA screening. Exosomes assist lncRNAs in carrying out their roles, offering a new target for creating endometriosis-specific medications. In order to serve as a reference for clinical research on the pathogenesis, diagnosis, and treatment options of endometriosis, this paper covers the role of exosome lncRNAs in endometriosis and related molecular mechanisms.

Status and related factors of postoperative recurrence of ovarian endometriosis: a cross-sectional study of 874 cases

PURPOSE

Exploring the status and related factors of postoperative recurrence of ovarian endometriosis.

METHODS

This study analyzed the results of questionnaires conducted in 27 hospitals across the country from January 2019 to November 2021. All women were divided into recurrence group and non-recurrence group to analyze the recurrence rate and related factors after ovarian endometriosis surgery.

RESULTS

The recurrence rates of ovarian endometriosis within 1 year, 1-2 years, 2-3 years, 3-4 years, 4-5 years and more than 5 years were 6.27%, 35.85%, 55.38%, 65.00% and 56.82%, respectively. Significant differences were found between two groups in terms of age at surgery (OR: 0.342, 95%CI: 0.244-0.481, P < 0.001), presence of dysmenorrhea (OR: 1.758, 95%CI: 1.337-2.312, P < 0.001), presence of adenomyosis (OR: 1.948, 95%CI: 1.417-2.678, P < 0.001) and family history of endometriosis or adenomyosis (OR: 1.678, 95%CI: 1.035-2.721, P = 0.021). The age at surgery (OR: 0.358, 95%CI: 0.253-0.506, P < 0.001), presence of dysmenorrhea (OR: 1.379, 95%CI: 1.026-1.853, P = 0.033) and presence of adenomyosis (OR: 1.799, 95%CI: 1.275-2.537, P = 0.001) were significantly associated with endometrioma recurrence in multivariate analysis. No significant associations were found between the recurrence rate and body mass index (BMI), educational background, age of menarche, gravida, parity, uterine leiomyoma, endometrial polyps or postoperative use of gonadotropin-releasing hormone agonist (GnRH-a).

CONCLUSIONS

Dysmenorrhea and presence of adenomyosis are independent risk factors for postoperative recurrence of ovarian endometriosis, and older age is an independent protective factor for postoperative recurrence.

Analysis of Long Non-Coding RNA (lncRNA) UCA1, MALAT1, TC0101441, and H19 Expression in Endometriosis

Endometriosis is a disease of complex etiology. Hormonal, immunological, and environmental factors are involved in its formation. In recent years, special attention has been paid to genetic mechanisms that can have a significant impact on the increased incidence of endometriosis. The study aimed to analyze the expression of four long non-coding RNA (lncRNA) genes, UCA1, MALAT1, TC0101441, and H19, in the context of the risk of developing endometriosis. The material for genetic testing for the expression of lncRNA genes were tissue slices embedded in paraffin blocks from patients with endometriosis (n = 100) and the control group (n = 100). Gene expression was determined by the RT-PCR technique. The expression of the H19 gene in endometriosis patients was statistically significantly lower than in the control group. A statistically significant association was found between H19 gene expression in relation to The Revised American Society for Reproductive Medicine classification of endometriosis (rASRM) in the group of patients with endometriosis. Research suggests that H19 expression plays an important role in the pathogenesis of endometriosis.

Estrogen Regulates the Expression and Function of lncRNA-H19 in Ectopic Endometrium

Background

Long noncoding RNAs (lncRNAs) are involved in the pathogenesis of endometriosis and can be regulated by estrogen. This study aimed to investigate the role of estrogen in regulating the expression and function of lncRNA-H19 in endometriosis.

Methods

Endometrial stromal cells (ESCs) were isolated from ectopic, eutopic endometrium with endometriosis and control endometrium without endometriosis, and lncRNA-H19 expression was detected using real-time polymerase chain reaction (RT-PCR). Ectopic endometrial stromal cells (ecESCs) were treated with 17β-estradiol at 10⁻⁸mol/L for 0, 12, 24 and 48 hours, and lncRNA-H19 expressions of cells were evaluated using RT-PCR. After ecESCs were treated with 17β-estradiol for 48 hours, lncRNA-H19 expression was knocked down and cell proliferative and invasive abilities were compared.

Results

The expression of lncRNA-H19 in ecESCs was significantly higher than that in eutopic endometrial stromal cells (euESCs) and control ESCs. After treated with 17β-estradiol, ecESCshadupregulatedlncRNA-H19 expression with time-dependent manner. Cell proliferation and invasion increased when estrogen upregulated lncRNA-H19 expression in ecESCs, however, cell proliferation restored and cell invasion did not change when lncRNA-H19 was knocked down in ecESCs.

Conclusion

The expression and function of lncRNA-H19 was regulated by estrogen in ecESCs, which probably contributed to the pathogenesis of endometriosis.

Altered gene expression of VEGF, IGFs and H19 lncRNA and epigenetic profile of H19-DMR region in endometrial tissues of women with endometriosis

Background

Endometriosis, as chronic estrogen-dependent disease, is defined by the presence of endometrial-like tissue outside the uterus. Proliferation of endometrial tissue and neoangiogenesis are critical factors in development of endometriosis. Hence, vascular endothelial growth factor (VEGF) as well as insulin‐like growth factor 1 and 2 (IGF1, 2) may be involved as inducers of cellular proliferation or neoangiogenesis. Imprinted long noncoding RNA H19 (lncRNA H19) has been suggested to be involved in pathogenesis of endometriosis via regulation of cellular proliferation and differentiation. Epigenetic aberrations appear to play an important role in its pathogenesis. The present study was designed to elucidate VEGF, IGF1, IGF2 and H19 lncRNA genes expression and epigenetic alterations of differentially methylated region (DMR) of H19 (H19-DMR) regulatory region in endometrial tissues of patients with endometriosis, in comparison with control women.

Methods

In this case–control study, 24 women with and without endometriosis were studied for the relative expression of VEGF, IGF1, IGF2 and H19 lncRNA genes using real-time polymerase chain reaction (PCR) technique. Occupancy of the MeCP2 on DMR region of H19 gene was assessed using chromatin immunoprecipitation (ChIP), followed by real-time PCR.

Results

Genes expression profile of H19, IGF1 and IGF2 was decreased in eutopic and ectopic endometrial tissues of endometriosis group, compared to the control tissues. Decreased expression of H19 in ectopic samples was significant in comparison with the controls (P < 0.05). Gene expression of VEGF was increased in eutopic tissues of endometriosis group, compared to control group. Whereas its expression level was lower in ectopic lesions versus eutopic and control endometrial samples. ChIP analysis revealed significant and nearly significant hypomethylation of H19-DMR region II in eutopic and ectopic samples, compared to the control group respectively. This epigenetic change was aligned with expression of IGF2. While methylation of H19-DMR region I was not significantly different between the eutopic, ectopic and control endometrial samples.

Conclusion

These data showed that VEGF, IGF1, IGF2 and H19 lncRNA genes expression and epigenetic alterations of H19 lncRNA have dynamic role in the pathogenesis of endometriosis, specifically in the way that hypomethylation of H19-DMR region II can be involved in IGF2 dysregulation in endometriosis.

Differential Expression and Bioinformatics Analysis of tRF/tiRNA in Endometriosis Patients

Background. Endometriosis (EMs) is a benign chronic condition that tends to recur in women of childbearing age, with an incidence of approximately 10%. It is a multifactorial disease for which the pathogenesis is currently unclear. This study is aimed at investigating the expression and clinical significance of tRNA-derived small RNA (tsRNA), a novel noncoding small RNA with potential regulatory functions, in endometriosis. Methods. The tRF/tiRNA expression profiles in endometrial tissues from three pairs of endometriosis patients and controls were detected by tRF&tiRNA PCR microarray technology and then verified by quantitative real-time polymerase chain reaction (qPCR). The target genes and target sites of TRF396, tiRNA-5030-GlnTTG-3, TRF308, and TRF320 were predicted by miRanda, and the network diagram of their interaction with miRNA was drawn. The impact of tRNA-derived fragments on the pathogenesis of endometriosis was analyzed using the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Results. Two upregulated and 19 downregulated tRNA-derived fragments were identified. The qRT-PCR results of 2 upregulated and 2 downregulated RNA-derived fragments were consistent with the RNA Seq data. The OR2B4 gene related to TRF396, the DGAT1 gene related to tiRNA-5030-GlnTTG-3, the KLF16 gene of TRF308, and the RNF213 gene of TRF320 had significant correlations. Gene Ontology and pathway analysis showed that the target genes of TRF396 and tiRNA-5030-GlnTTG-3 were mainly involved in the intrinsic components of the membrane and the overall composition of the membrane in cell components; molecular functions mainly involve olfactory conduction and G protein-coupled receptor activity. In the biological process, it was mainly involved in the detection of sensory stimuli. The target genes of TRF308 and TRF320 were mainly involved in the intracellular part; molecular functions are mainly related to DNA binding transcription factor activity and protein binding and mainly related to biological regulation of biological processes. Pathway analysis showed that the RAP1 signaling pathway and the AXON GUIDANCE signaling pathway may participate in the progression of endometriosis. Conclusion. The differential expression of tRF/tiRNA in endometriosis may be related to the pathogenesis of endometriosis. Furthermore, tRF/tiRNA may be a biomarker for the diagnosis and treatment of EMs in the future.

Upregulation of h-TERT and Ki-67 in ectopic endometrium is associated with recurrence of endometriosis

At present, endometriosis remains a worldwide health burden, with the main symptoms of dysmenorrhea, chronic pelvic pain, and infertility, markedly reducing the quality of life (de Ziegler et al., 2010). Although there is no proof that the disease is associated with high mortality, this disorder can significantly contribute to the deterioration of women's general well-being (McPeak et al., 2018). The main current treatment for endometriosis is surgery to remove endometriotic lesions; however, the recurrence rate following surgical treatment is as high as 21.5% at two years and 40.0%‍-‍50.0% at five years post-surgery (Koga et al., 2015). To prevent recurrence, adjuvant treatment with drugs after surgery is recommended to prolong relapse-free intervals. However, it is inconvenient for patients to continuously use such medications in terms of adverse effects and cost (Turk, 2002).

miR-206 Targets MALAT1 to Suppress Cell Progression of Ectopic Endometrial Stromal Cells in Endometriosis

BACKGROUND

miR-206 was reported to be a tumor suppressor in bladder cancer. In this study, we explore the expression and function of miR-206 in endometriosis (EM).

METHODS

40 EM patients undergoing total hysterectomy were selected as the experimental group. RT-qPCR assay was adopted to detect the expression of MALAT1 and miR-206 in EM. Cell proliferation was detected by EdU incorporation and colony formation assay. Cell migration and invasion viability of ESCs were examined by transwell assay and wound healing assay. Flow cytometry was carried out to assess cell apoptosis of ESCs. The protein expressions of Bcl-2 and Bax were examined by western blot assay. The relationship between miR-206 and MALAT1 was verified by the dual-luciferase reporter assay and RNA pull-down assay.

RESULTS

In this work, miR-206 was found to be downregulated in EM. Functional experiments displayed that miR-206 mimic repressed cell proliferation, migration, and invasion of ESCs and promoted cell apoptosis of ESCs. Furthermore, miR-206 mimic reduced the expression of Bcl-2 but enhanced the expression of Bax. MALAT1 was found to be upregulated in EM. Furthermore, MALAT1 was indicated to be a target of miR-206. Additionally, MALAT1 was found to alleviate the influence of miR-206 on cell progression of ESCs. Furthermore, miR-206 inhibited tumor growth in vivo.

CONCLUSION

This study indicated that miR-206 inhibited cell progression by regulating MALAT1 in EM. Hence, miR-206 was suggested to be a possible target for EM treatment.

The Role of Long Non-Coding RNAs in Endometriosis

Endometriosis is a chronic gynecological disorder affecting the quality of life and fertility of many women around the world. Heterogeneous and non-specific symptoms may lead to a delay in diagnosis, with treatment options limited to surgery and hormonal therapy. Hence, there is a need to better understand the pathogenesis of the disease to improve diagnosis and treatment. Long non-coding RNAs (lncRNAs) have been increasingly shown to be involved in gene regulation but remain relatively under investigated in endometriosis. Mutational and transcriptomic studies have implicated lncRNAs in the pathogenesis of endometriosis. Single-nucleotide polymorphisms (SNPs) in lncRNAs or their regulatory regions have been associated with endometriosis. Genome-wide transcriptomic studies have identified lncRNAs that show deregulated expression in endometriosis, some of which have been subjected to further experiments, which support a role in endometriosis. Mechanistic studies indicate that lncRNAs may regulate genes involved in endometriosis by acting as a molecular sponge for miRNAs, by directly targeting regulatory elements via interactions with chromatin or transcription factors or by affecting signaling pathways. Future studies should concentrate on determining the role of uncharacterized lncRNAs revealed by endometriosis transcriptome studies and the relevance of lncRNAs implicated in the disease by in vitro and animal model studies.

Translational Applications of Linear and Circular Long Noncoding RNAs in Endometriosis

Endometriosis is a chronic gynecologic disease that negatively affects the quality of life of many women. Unfortunately, endometriosis does not have a cure. The current medical treatments involve hormonal manipulation with unwanted side effects and high recurrence rates after stopping the medication. Sadly, a definitive diagnosis for endometriosis requires invasive surgical procedures, with the risk of complications, additional surgeries in the future, and a high rate of recurrence. Both improved therapies and noninvasive diagnostic tests are needed. The unique molecular features of endometriosis have been studied at the coding gene level. While the molecular components of endometriosis at the small RNA level have been studied extensively, other noncoding RNAs, such as long intergenic noncoding RNAs and the more recently discovered subset of long noncoding RNAs called circular RNAs, have been studied more limitedly. This review describes the molecular formation of long noncoding and the unique circumstances of the formation of circular long noncoding RNAs, their expression and function in endometriosis, and promising preclinical studies. Continued translational research on long noncoding RNAs, including the more stable circular long noncoding RNAs, may lead to improved therapeutic and diagnostic opportunities.

Endometriosis: Epidemiology, Classification, Pathogenesis, Treatment and Genetics (Review of Literature)

Endometriosis is a “mysterious” disease and its exact cause has not yet been established. Among the etiological factors, congenital, environmental, epigenetic, autoimmune and allergic factors are listed. It is believed that the primary mechanism of the formation of endometriosis foci is retrograde menstruation, i.e., the passage of menstrual blood through the fallopian tubes into the peritoneal cavity and implantation of exfoliated endometrial cells. However, since this mechanism is also observed in healthy women, other factors must also be involved in the formation of endometriosis foci. Endometriosis is in many women the cause of infertility, chronic pain and the deterioration of the quality of life. It also represents a significant financial burden on health systems. The article presents a review of the literature on endometriosis—a disease affecting women throughout the world.

The value of long noncoding RNAs for predicting the recurrence of endometriosis: A protocol for meta-analysis and bioinformatics analysis

BACKGROUND

As a gynecological disease, endometriosis (EM) seriously endangers the health of women at the age of childbearing and is closely related to long noncoding RNAs (lncRNAs). Current studies have discovered that there are differential expressions of many kinds of lncRNAs in EM. However, whether lncRNAs can be applied as a new marker for the prediction of the recurrence of EM is still controversial. In this study, meta-analysis and bioinformatics analysis were carried out to explore the value of lncRNAs as a predictor of the recurrence of EM and to analyze its biological role.

METHODS

PubMed, Embase, and Web of Science databases were searched through computer and the articles published from the self-built database to April 2021 were collected. According to the inclusion and exclusion criteria, the literature was screened, and the quality of the inclusion study was evaluated. Stata 16.0 software was used for meta-analysis. The co-expression genes related to lncRNAs were screened by online tool Co-LncRNA. Then David for Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis were conducted. A competitive endogenous RNA network that may exist in lncRNAs through Starbase was built.

RESULTS

The results of this meta-analysis would be submitted to peer-reviewed journals for publication.

CONCLUSION

This meta-analysis could provide high-quality evidence support for lncRNAs, so as to predict the recurrence of EM. At the same time, we use bioinformatics technology to predict and analyze its biological effects, which provides a theoretical basis for further experimental verification.

ETHICS AND DISSEMINATION

The private information from individuals will not be published. This systematic review also should not damage participants' rights. Ethical approval is not available. The results may be published in a peer-reviewed journal or disseminated in relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/MF3QJ.