In Vitro and In Vivo Effects of Tumor Suppressor Gene PTEN on Endometriosis: An Experimental Study

Parthenolide repressed endometriosis induced surgically in rats: Role of PTEN/PI3Kinase/AKT/GSK-3β/β-catenin signaling in inhibition of epithelial mesenchymal transition

AIM

PI3K/AKT/GSK-3β/β-catenin signaling pathway is a triggering factor for epithelial to mesenchymal transition (EMT) which plays a pivotal role in the pathogenesis of endometriosis. Parthenolide is a sesquiterpene lactone extract that has anti-inflammatory, analgesic and anticancer properties. Hence, we investigated the effect of parthenolide against EMT in the endometrial tissue implants and immortalized epithelial endometriotic cell lines 12Z.

MAIN METHODS

Twenty- four female Rats with surgically induced endometriosis were treated with parthenolide (2, 4 mg/kg), for 4 weeks. Endometriotic cell line 12Z was used to identify the effect of parthenolide on the wound healing, cellular migration and invasion properties of endometriotic cells.

KEY FINDINGS

Parthenolide decreased the endometriotic implant tissue expression of total PI3K, PI3K-p85, p-AKT, p/total AKT, p-GSK-3β, P/total GSK-3β, and nβ-catenin, as well as increased E-cadherin and decreased vimentin mRNA expression. Parthenolide upregulated PTEN immunoreactivity as well as the endometriotic tissue caspase-3, caspase-9, BAX levels while reducing Bcl2 level. Additionally, parthenolide decreased endometriotic tissue implants surface area and histopathological score of the epithelial growth.

SIGNIFICANCE

Our findings showed that parthenolide in a dose dependent manner inhibited PI3K/AKT/GSK-3β/nβ-catenin cascade via enhancement of PTEN with subsequent inhibition of EMT evidenced by elevation of the epithelial marker, E-cadherin and reduction of mesenchymal marker, vimentin, of the endometriotic implants in addition to reversal of invasion and migration properties of epithelial endometriotic cell lines. These findings provide a valuable therapeutic approach for treatment of endometriosis.

Molecular Mechanisms of Endometriosis Revealed Using Omics Data

Endometriosis is a gynecological disorder prevalent in women of reproductive age. The primary symptoms include dysmenorrhea, irregular menstruation, and infertility. However, the pathogenesis of endometriosis remains unclear. With the advent of high-throughput technologies, various omics experiments have been conducted to identify genes related to the pathophysiology of endometriosis. This review highlights the molecular mechanisms underlying endometriosis using omics. When genes identified in omics experiments were compared with endometriosis disease genes identified in independent studies, the number of overlapping genes was moderate. However, the characteristics of these genes were found to be equivalent when functional gene set enrichment analysis was performed using gene ontology and biological pathway information. These findings indicate that omics technology provides invaluable information regarding the pathophysiology of endometriosis. Moreover, the functional characteristics revealed using enrichment analysis provide important clues for discovering endometriosis disease genes in future research.

Endometriosis and ovarian cancer risk, an epigenetic connection

Endometriosis is a gynecological disorder that affects 176 million women worldwide and 1 in 10 females in the United States. Endometriosis most often affects women of child-bearing age, with most going undiagnosed. Endometriosis also shares many characteristics common to invasive cancer and has been known to be associated with epithelial ovarian cancer. Ovarian cancer is the 11^th most common cancer among women and over 22,000 new cases will be diagnosed within the next year. Women most commonly diagnosed with this cancer are between the ages of 55–64 years, outside the range of the age of women affected with endometriosis. While no known cause of either disease has been established, epigenetic regulation is thought to play a major role in both. This review focuses on epigenetic changes that occur within each individual disease as well as those that are similar in both, suggesting a possible etiological link between the two diseases.

Association of genetic variations in phosphatase and tensin homolog (PTEN) gene with polycystic ovary syndrome in South Indian women: a case control study

PURPOSE

The purpose of the study was to investigate the association between gene phosphate and tensin homolog (PTEN) single nucleotide polymorphisms (SNPs) and risk of developing polycystic ovary syndrome (PCOS) in South Indian women. PTEN is one of the most important tumor suppressor genes that regulate cell proliferation, migration, and death. It is also involved in the maintenance of genome stability. PCOS is one of the most common endocrine disorders among women of reproductive age. It is a heterogeneous syndrome characterized by abnormal reproductive cycles, irregular ovulation, hormonal imbalance, hyperandrogenism, acne and hirsutism.

RESEARCH QUESTION

What is the association status of PTEN SNPs with PCOS?

METHODS

A total of 240 subjects were recruited in this case-control study comprising 110 patients with PCOS and 130 individuals without PCOS. All the subjects were of South Indian origin. The genotyping of PTEN SNPs (rs1903858 A/G, rs185262832G/A and rs10490920T/C) was carried out on DNA from subjects by polymerase chain reaction (PCR) and sequencing analysis. Haplotype frequencies for multiple loci and the standardized disequilibrium coefficient (D') for pairwise linkage disequilibrium (LD) were surveyed by Haploview Software.

RESULTS

Our results showed significant increase in the frequencies of rs1903858 A/G (P = 0.0016), rs185262832 G/A (P = 0.0122) and rs10490920 T/C (P = 0.0234) genotypes and alleles in cases compared to controls.

CONCLUSION

The PTEN (rs1903858A/G, rs185262832G/A and rs10490920T/C) gene polymorphisms may constitute an inheritable risk factor for PCOS in South Indian women.

Malignant Transformation and Associated Biomarkers of Ovarian Endometriosis: A Narrative Review

This review focuses on pathogenesis of endometriosis, its possible biomarkers and role in endometriosis-associated ovarian cancer. We analyzed various databases to obtain new insights, theories, and biomarkers associated with endometriosis. There are several theories of endometriosis development and biomarker changes including atypical forms. A number of studies have attempted to establish specific, reliable biomarkers to help diagnose endometriosis and endometriosis-associated diseases on the basis of different pathogenetic pathways. Nevertheless, despite intensive research extending even to the molecular level, the origin, natural history, malignant transformation, and laboratory management of endometriosis and related diseases are not yet clearly defined. Therefore, early laboratory diagnoses of endometriosis, its atypical form, and endometriosis-associated ovarian tumors are important problems that require further study in the context of advanced therapeutic strategies to provide maximal health benefits to patients.

Endometriosis: A Malignant Fingerprint

BACKGROUND

Endometriosis is complex, but identifying the novel biomarkers, inflammatory molecules, and genetic links holds the key to the enhanced detection, prediction and treatment of both endometriosis and endometriosis related malignant neoplasia. Here we review the literature relating to the specific molecular mechanism(s) mediating tumorigenesis arising within endometriosis.

METHODS

Guidance (e.g. Cochrane) and published studies were identified. The Published studies were identified through PubMed using the systematic review methods filter, and the authors' topic knowledge. These data were reviewed to identify key and relevant articles to create a comprehensive review article to explore the molecular fingerprint associated with in endometriosis-driven tumorigenesis.

RESULTS

An important focus is the link between C3aR1, PGR, ER1, SOX-17 and other relevant gene expression profiles and endometriosis-driven tumorigenesis. Further studies should also focus on the combined use of CA-125 with HE-4, and the role for OVA1/MIA as clinically relevant diagnostic biomarkers in the prediction of endometriosis-driven tumorigenesis.

CONCLUSIONS

Elucidating endometriosis' molecular fingerprint is to understand the molecular mechanisms that drive the endometriosis-associated malignant phenotype. A better understanding of the predictive roles of these genes and the value of the biomarker proteins will allow for the derivation of unique molecular treatment algorithms to better serve our patients.

In-vitro models of human endometriosis

Endometriosis is one of the most common benign gynecological diseases in women of reproductive age worldwide. In past decades, a number of in-vitro models have been used to investigate the pathology and therapeutic methods for the treatment of endometriosis. The current review summarized the majority of currently available in-vitro models, which utilize a variety of cell or tissues types, including endometriotic cell lines, primary endometrial stromal cells, endometrial stem cells, endometrial explants, peritoneal explants and immune cells. These cells or tissues are cultured individually, co-cultured in 2D or 3D systems with various matrices or cultured in chicken chorioallantotic membranes and amniotic membranes culture systems. These models are able to represent one or more aspects of the process of endometriosis. These models are helpful and can be used to investigate the development of endometriosis and the underlying mechanisms of this disorder in detail, and help investigators select appropriate models for their experiments. Recently, the new concept of endometriosis as a fibrotic condition will lead research to investigate the differentiation of myofibroblasts and the development of fibrosis in endometriotic lesions, which will increase the development of novel models that can be used to investigate endometriotic fibrosis.

PDCD4 suppresses proliferation, migration, and invasion of endometrial cells by inhibiting autophagy and NF-κB/MMP2/MMP9 signal pathway

Endometriosis (EM) is a kind of estrogen-dependent disease in reproductive-age women. Ovarian EM is the most common type. Although EM is a benign disease, it shares many similar features with cancers. Programmed cell death 4 (PDCD4), a newly identified tumor suppressor, plays an important role in inhibiting tumorigenesis and tumor progression at the transcriptional and translational levels. To explore the roles of PDCD4 in EM, we detected the expression of PDCD4 in control endometrium and eutopic/ectopic endometrium of ovarian EM patients, and analyzed the effects of PDCD4 on the biological behaviors of endometrial cell lines and primary endometrial cells. The results demonstrated that PDCD4 was downregulated in eutopic and ectopic endometrium of EM patients compared with control endometrium. PDCD4 effectively inhibited the proliferation and colony-forming ability of endometrial cells maybe by inhibiting cell autophagy. In addition, PDCD4 also suppressed the migration and invasion ability of endometrial cells, the mechanism may be related to NF-κB/MMP2/MMP9 signal pathway. Taken together, these results suggest that PDCD4 could be involved in the pathogenesis of EM, and provide a novel approach to target the aberrant PDCD4 expression in EM.

Cai's Neiyi Prescription promotes apoptosis and inhibits inflammation in endometrial stromal cells with endometriosis through inhibiting USP10

To observe the effect of Cai's Neiyi Prescription (CNYP) on the apoptosis and inflammation in endometrial stromal cells with endometriosis (EM) both in vivo and in vitro, EM model rats and endometrial stromal cells were treated with CNYP and the level of USP10, p-ERK1/2, ERK1/2, and apoptosis-related protein as well as the levels of proinflammatory factors were measured by Western blotting and ELISA, respectively. Rats with surgically induced EM showed increased USP10 expression and ERK/2 activation. Intragastric administration of CNYP granule significantly inhibited EM-induced ERK1/2 activation and expression of USP10 and Bcl-2, but increased the expression of Bax and Caspase-7 in EM-induced rats. CNYP granule administration also inhibited EM-induced inflammation in rats. Moreover, the ectopic endometrial stromal cells isolated from EM patients demonstrated decreased ERK1/2 activation and expression of USP10 and Bcl-2 and increased expression of Bax and Caspase-7 after cultured in DMEM containing CNYP-medicated rat serum, which were reversed by USP10 overexpression and were enhanced by USP10 siRNA. USP10 overexpression also inhibited while USP10 siRNA enhanced the CNYP-induced inhibition of inflammation in ectopic endometrial stromal cells. Taken together, our results suggest that CNYP granule promotes apoptosis and inhibits inflammation in endometrial stromal cells with EM through inhibiting USP10.

USP10 promotes proliferation and migration and inhibits apoptosis of endometrial stromal cells in endometriosis through activating the Raf-1/MEK/ERK pathway

Endometriosis has been initially described as endometrial-like tissue outside of the uterine cavity. The mitogen-activated protein kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway playing an important role in the regulation of cell proliferation, apoptosis, and migration has been found to be activated in endometriosis. However, regulation of the MEK/ERK signaling pathway in endometriosis has not been fully understood. In this study, primary-cultured endometrial stromal cells were collected from patients with endometriosis and healthy controls, and the proliferation, apoptosis, and migration of ectopic endometrial stromal cells transfected with ubiquitin-specific protease 10 (USP10)-small-interfering RNA (siRNA) or pLVX-Puro-USP10 with or without MEK inhibitor PD-98059 or exogenous signaling stimulation such as epidermal growth factor (EGF) were measured by CCK-8, flow cytometry, and Transwell, respectively. The gene and protein expressions were measured by real-time PCR or Western blot. USP10 overexpression promoted ectopic endometrial stromal cell migration and proliferation, suppressed cell apoptosis, and activated MEK/ERK signaling that is a critical downstream target of the serine/threonine protein kinase Raf-1, which was significantly blocked by PD-98059. USP10 silencing demonstrated the inverse effects, and these effects induced by USP10 silencing were significantly blocked by EGF. USP10 overexpression promoted Raf-1 protein expression, but not mRNA expression, through deubiquitination. In conclusion, these results suggest that USP10 promotes proliferation and migration and inhibits apoptosis of endometrial stromal cells in endometriosis through activating the Raf-1/MEK/ERK pathway.

Cancer driver mutations in endometriosis: Variations on the major theme of fibrogenesis

BACKGROUND

One recent study reports cancer driver mutations in deep endometriosis, but its biological/clinical significance remains unclear. Since the natural history of endometriosis is essentially gradual progression toward fibrosis, it is thus hypothesized that the six driver genes reported to be mutated in endometriosis (the RP set) may play important roles in fibrogenesis but not necessarily malignant transformation.

METHODS

Extensive PubMed search to see whether RP and another set of driver genes not yet reported (NR) to be mutated in endometriosis have any roles in fibrogenesis. All studies reporting on the role of fibrogenesis of the genes in both RP and NR sets were retrieved and evaluated in this review.

RESULTS

All six RP genes were involved in various aspects of fibrogenesis as compared with only three NR genes. These nine genes can be anchored in networks linking with their upstream and downstream genes that are known to be aberrantly expressed in endometriosis, piecing together seemingly unrelated findings.

CONCLUSIONS

Given that somatic driver mutations can and do occur frequently in physiologically normal tissues, it is argued that these mutations in endometriosis are not necessarily synonymous with malignancy or premalignancy, but the result of enormous pressure for fibrogenesis.

Basic mechanisms of vascularization in endometriosis and their clinical implications

BACKGROUND

Vascularization is a major hallmark in the pathogenesis of endometriosis. An increasing number of studies suggests that multiple mechanisms contribute to the vascularization of endometriotic lesions, including angiogenesis, vasculogenesis and inosculation.

OBJECTIVE AND RATIONALE

In this review, we provide an overview of the basic mechanisms of vascularization in endometriosis and give special emphasis on their future clinical implications in the diagnosis and therapy of the disease.

SEARCH METHODS

Literature searches were performed in PubMed for English articles with the key words 'endometriosis', 'endometriotic lesions', 'angiogenesis', 'vascularization', 'vasculogenesis', 'endothelial progenitor cells' and 'inosculation'. The searches included both animal and human studies. No restriction was set for the publication date.

OUTCOMES

The engraftment of endometriotic lesions is typically associated with angiogenesis, i.e. the formation of new blood vessels from pre-existing ones. This angiogenic process underlies the complex regulation by angiogenic growth factors and hormones, which activate intracellular pathways and associated signaling molecules. In addition, circulating endothelial progenitor cells (EPCs) are mobilized from the bone marrow and recruited into endometriotic lesions, where they are incorporated into the endothelium of newly developing microvessels, referred to as vasculogenesis. Finally, preformed microvessels in shed endometrial fragments inosculate with the surrounding host microvasculature, resulting in a rapid blood supply to the ectopic tissue. These vascularization modes offer different possibilities for the establishment of novel diagnostic and therapeutic approaches. Angiogenic growth factors and EPCs may serve as biomarkers for the diagnosis and classification of endometriosis. Blood vessel formation and mature microvessels in endometriotic lesions may be targeted by means of anti-angiogenic compounds and vascular-disrupting agents.

WIDER IMPLICATIONS

The establishment of vascularization-based approaches in the management of endometriosis still represents a major challenge. For diagnostic purposes, reliable angiogenic and vasculogenic biomarker panels exhibiting a high sensitivity and specificity must be identified. For therapeutic purposes, novel compounds selectively targeting the vascularization of endometriotic lesions without inducing severe side effects are required. Recent progress in the field of endometriosis research indicates that these goals may be achieved in the near future.

Long non-coding RNA LINC00261 inhibits cell growth and migration in endometriosis

AIM

A previous study reported that LINC00261 is significantly downregulated in human ectopic endometrial tissues. The present study aimed to explore whether LINC00261 is functional in endometriosis cell proliferation, apoptosis and migration.

METHODS

By transfecting human endometriosis cell line CRL-7566 with plasmids containing LINC00261, we successfully established the cell CRL-7566/LINC00261 with a high LINC00261 expression level. Cell-counting kit-8 and colony formation assays were conducted to evaluate the effect of LINC00261 on cell proliferation, and flow cytometry analysis and transwell migration assay were conducted to evaluate its effect on cell apoptosis and cell migration, respectively.

RESULTS

Cell-counting kit-8 and colony formation assays both indicated that LINC00261 could inhibit cell proliferation in CRL-7566. Flow cytometry analysis confirmed that LINC00261 mediated inhibition of cell proliferation, which might be a consequence of inducting apoptosis. Furthermore, transwell migration assay indicated that LINC00261 could inhibit cell migration in endometriosis.

CONCLUSION

LncRNA LINC00261 is capable of inhibiting cell growth and migration in endometriosis.