Increased expression of CYP1A1 and CYP1B1 in ovarian/peritoneal endometriotic lesions

An exceptional case of degenerative endometriosis of the uterine torus

There are less than ten cases of deep endometriosis degeneration in the literature. The duration of endometriosis, the ovarian stimulation, the perimenopause and the obesity exposes the woman to an increased risk of endometriosis degeneration.

Role of AMPK/mTOR, mitochondria, and ROS in the pathogenesis of endometriosis

Endometriosis is the presence of endometrial tissue outside the uterine cavity usually in the ovaries, fallopian tube, and pelvic cavity. It's a chronic enigmatic gynecological condition associated with dysmenorrhea, dyspareunia, pelvic pain, and infertility. Endometriosis lesions exist in a unique microenvironment characterized by increased concentrations of hormones, inflammation, and oxidative stress. This environment promotes cell survival through the binding of membrane receptors and subsequent cascading activation of intracellular kinases that stimulate a cellular response. In endometriosis, well-established signaling pathways, mTOR and AMPK, are altered via steroid hormones and other factors to promote cell growth, migration, and proliferation. This is accompanied by dysfunction in the mitochondria that increase energy production to sustain proliferation demands consequently leading to reactive oxygen species overproduction. This review aims to summarize the role of altered mTOR/AMPK signaling pathway, mitochondrial dysfunction, and reactive oxygen species overproduction along with providing therapeutic and diagnostic approaches. Highlighting these factors would provide a better understanding to reach a coherent theory for the pathogenesis of endometriosis.

Next-Generation Sequencing analysis discloses genes implicated in equine endometrosis that may lead to tumorigenesis

Endometrosis is a periglandular fibrosis associated with dysfunction of affected glandular epithelial cells that is the most common cause of reduced fertility in mares, although it is not fully understood. The etiology of the disease is still partially unknown. This study focuses on understanding the genetic mechanisms potentially underlying endometrosis in mares using the Next Generation Sequencing (NGS) technique. Endometrial samples, used in the study, were obtained in the anestrus phase both from healthy mares and those diagnosed with endometrosis. The NGS data were analyzed for gene involvement in biological processes and pathways (e.g. STAR, KOBAS-I, STRING, and ClustVis software). Bioinformatic analysis revealed differential expression of 55 transcripts. In tissues with endometrosis, most genes displayed upregulated expression. The protein-protein interaction analysis disclosed a substantial transcript network including transcripts related to metabolism e.g. sulfur metabolism (SELENBP1), ovarian steroidogenesis, steroid hormone biosynthesis, and chemical carcinogenesis (CYP1B1), COXs (COX4I1, COX3, UQCRFS1) as well as transcripts related to immune response e.g. MMP7, JCHAIN, PIGR, CALR, B2M, FCGRT. Interestingly, the latter has been previously linked with various pathologies including cancers in the female reproductive system. In conclusion, this study evaluated genes that are not directly impacted by sex hormone feedback, but that create a metabolic and immune environment in tissues, thus influencing fertility and pregnancy in mares with endometrosis. Moreover, some of the identified genes may be implicated in tumorigenesis of endometrial lesions. These data may be useful as a starting point in further research, such as the development of targeted strategies for rapid diagnosis and/or prevention of this pathology based on gene and protein-protein interactions.

Site-Specific Regulation of Sulfatase and Aromatase Pathways for Estrogen Production in Endometriosis

Endometriosis is a highly prevalent gynecological disease characterized by lesions in different sites. Regulation of specific estrogen pathways may favor the formation of distinct microenvironments and the progression of endometriosis. However, no study has simultaneously evaluated the gene and protein regulation of the main estrogen-synthesizing enzymes in endometriosis. Thus, our goals were to study the relationship between gene and protein expression of aromatase (CYP19A1 or ARO), steroid sulfatase (STS), and hydroxysteroid 17-beta dehydrogenase (HSD17B1) in superficial (SUP), ovarian (OMA), and deep infiltrating (DIE) endometriotic lesion sites as well as in the eutopic endometrium of patients with (EE) and without (control) endometriosis in the same and large cohort of patients. The site-specific expression of these enzymes within different cells (glandular and stromal components) was also explored. The study included 108 patients surgically diagnosed with endometriosis who provided biopsies of EE and endometriotic lesions and 16 disease-free patients who collected normal endometrium tissue. Our results showed that CYP19A1 was detected in all endometriosis tissues and was in higher levels than in control. Unique patterns of the STS and HSD17B1 levels showed that they were most closely regulated in all tissues, with manifestation at greater levels in DIE compared to the other endometriotic lesion sites, OMA and SUP. Gene and protein expression of ARO, STS, and HSD17B1 occurred at different rates in endometriotic sites or EE. The distinctive levels of these estrogen-synthesizing enzymes in each endometriotic site support the hypothesis of a tissue microenvironment that can both influence and be influenced by the expression of different estrogenic pathways, locally affecting the availability of estrogen needed for maintenance and progression of endometriotic lesions.

Circulating estradiol and its biologically active metabolites in endometriosis and in relation to pain symptoms

OBJECTIVES

Endometriosis (EM) is an estrogen-dominant inflammatory disease linked to infertility that affects women of reproductive age. EM lesions respond to hormonal signals that regulate uterine tissue growth and trigger inflammation and pain. The objective of this study was to evaluate whether estradiol (E₂) and its biologically active metabolites are differentially associated with EM given their estrogenic and non-estrogenic actions including proliferative and inflammatory properties.

DESIGN

We performed a retrospective study of 209 EM cases and 115 women without EM.

METHODS

Pain-related outcomes were assessed using surveys with validated scales. Preoperative serum levels of estradiol (E₂) and estrone (E₁), their 2-, 4- and 16- hydroxylated (OH) and methylated (MeO) derivatives (n=16) were measured by mass spectrometry. We evaluated the associations between estrogen levels and EM anatomic sites, surgical stage, risk of EM, and symptoms reported by women. Spearman correlations established the relationships between circulating steroids.

RESULTS

Of the sixteen estrogens profiled, eleven were detected above quantification limits in most individuals. Steroids were positively correlated, except 2-hydroxy 3MeO-E₁ (2OH-3MeO-E₁). Higher 2OH-3MeO-E₁ was linked to an increased risk of EM (Odd ratio (OR)=1.91 (95%CI 1.09-3.34); P=0.025). Ovarian EM cases displayed enhanced 2-hydroxylation with higher 2MeO-E₁ and 2OH-E₁ levels (P< 0.009). Abdominal, pelvic and back pain symptoms were also linked to higher 2OH-3MeO-E₁ levels (OR=1.86; 95%CI 1.06-3.27; P=0.032).

CONCLUSIONS

The 2-hydroxylation pathway emerges as an unfavorable feature of EM, and is associated with ovarian EM and pain related outcomes.

Catecholestradiol Activation of Adrenergic Receptors Induces Endometrial Cell Survival via p38 MAPK Signaling

CONTEXT

Enhanced levels of catecholestradiols, 2-hydroxyestradiol (2-OHE2) or 4-hydroxyestradiol (4-OHE2), are reported in endometriosis. During gestation, catecholestradiol activation of adrenergic receptors (AR) elevates estrogen receptor (ER)-independent proliferation of uterine arterial endothelial cells.

OBJECTIVE

To investigate β-AR-mediated catecholestradiol effects on human endometrial stromal cell (HESC) and epithelial cell survival in endometriosis.

DESIGN

β-AR immunostaining of eutopic and ectopic endometria (n = 9). Assays for cell viability, 5-bromo-2'-deoxyuridine proliferation, apoptosis, quantitative PCR, and estrogenicity (alkaline phosphatase activity), as well as siRNA β-AR silencing and immunoblot analyses of cultured HESCs or Ishikawa cells treated with control or 2-OHE2 or 4-OHE2 ±β-AR antagonist or ±p38 MAPK inhibitor.

SETTING

University research institution.

PATIENTS

Women with or without endometriosis.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

β-AR expression in eutopic vs ectopic endometria and regulation of HESC survival by 2-OHE2 and 4-OHE2.

RESULTS

Eutopic and ectopic endometrial stromal and epithelial cells displayed β2-AR immunoreactivity with increased staining in the functionalis vs basalis layer (P < 0.05). Both 2-OHE2 and 4-OHE2 enhanced HESC and Ishikawa cell survival (P < 0.05), an effect abrogated by β-AR antagonist propranolol, but not ER antagonist ICI182,780. 2-OHE2 or 4-OHE2 failed to induce cell survival and estrogenic activity in ADRB2-silenced HESCs and in Ishikawa cells, respectively. Although 2-OHE2 inhibited apoptosis and BAX mRNA expression, 4-OHE2 induced proliferation and decreased apoptosis (P < 0.05). Both catecholestradiols elevated phospho-p38 MAPK levels (P < 0.05), which was blocked by propranolol, and p38 MAPK inhibitor reversed catecholestradiol-enhanced HESC survival.

CONCLUSIONS

Catecholestradiols increase endometrial cell survival by an ER-independent β-AR-mediated p38 MAPK activation, suggesting that agents blocking β-AR (e.g., propranolol) or inhibiting 2-OHE2- or 4-OHE2-generating enzymes (i.e., CYP1A1/B1) could treat endometriosis.

Polymorphisms in the 3 ′ UTR Region of ESR2 and CYP19A1 Genes and Its Influence on Allele-Specific Gene Expression in Endometriosis

Objectives. Endometriosis is supported by hormonal, immunological, and environmental factors. No specific marker for endometriosis has yet been identified. ESR2 and CYP19A1 genes play a major role in the hormonal control of endometriosis women, the development of which largely depends on steroid hormones. Aim. An analysis of ESR2 and CYP19A1 allele-specific gene expressions in the context of the risk for endometriosis occurrence. Methods. The study material included paraffin-embedded tissue specimens, collected from patients ( $n=100$ ) with endometriosis. Blood samples from age-matched, endometriosis-free women ( $n=100$ ) served as a control. the RT-PCR technique was performed to observe the expression of ESR2 and CYP19A1 genes. Moreover, Sanger’s sequencing method was applied for polymorphism analysis. Results. A set of 4 single-nucleotide polymorphisms (SNPs) was determined; all of them most significantly associated with endometriosis: rs4986938 (G>A)(chromosome 14), rs928554 (A>G) (chromosome 14), rs10046 (C>T) (chromosome 15), and rs4646 (C>A) (chromosome 15). There were no differences in the distribution of genotypes and alleles in the studied groups, taking into account ESR2 and CYP19A1 gene expressions. Conclusion. The ESR2 and CYP19A1 polymorphisms may not be correlated with endometriosis susceptibility. Further analysis is needed to specify the role of these polymorphisms in the pathogenesis of endometriosis.

Cancer-associated mutations in endometriosis: shedding light on the pathogenesis and pathophysiology

BACKGROUND

Endometriosis is a benign gynaecological disease. Thus, it came as a complete surprise when it was reported recently that the majority of deep endometriosis lesions harbour somatic mutations and a sizeable portion of them contain known cancer-associated mutations (CAMs). Four more studies have since been published, all demonstrating the existence of CAMs in different subtypes of endometriosis. While the field is still evolving, the confirmation of CAMs has raised many questions that were previously overlooked.

OBJECTIVE AND RATIONALE

A comprehensive overview of CAMs in endometriosis has been produced. In addition, with the recently emerged understanding of the natural history of endometriotic lesions as well as CAMs in normal and apparently healthy tissues, this review attempts to address the following questions: Why has there been such a wild discrepancy in reported mutation frequencies? Why does ectopic endometrium have a higher mutation rate than that of eutopic endometrium? Would the presence of CAMs in endometriotic lesions increase the risk of cancer to the bearers? Why do endometriotic epithelial cells have much higher mutation frequencies than their stromal counterpart? What clinical implications, if any, do the CAMs have for the bearers? Do these CAMs tell us anything about the pathogenesis and/or pathophysiology of endometriosis?

SEARCH METHODS

The PubMed database was searched, from its inception to September 2019, for all papers in English using the term 'endometriosis and CAM', 'endometriosis and cancer-driver mutation', 'somatic mutations', 'fibrosis', 'fibrosis and epigenetic', 'CAMs and tumorigenesis', 'somatic mutation and normal tissues', 'oestrogen receptor and fibrosis', 'oxidative stress and fibrosis', 'ARID1A mutation', and 'Kirsten rat sarcoma mutation and therapeutics'. All retrieved papers were read and, when relevant, incorporated into the review results.

OUTCOMES

Seven papers that identified CAMs in endometriosis using various sequencing methods were retrieved, and their results were somewhat different. Yet, it is apparent that those using microdissection techniques and more accurate sequencing methods found more CAMs, echoing recent discoveries that apparently healthy tissues also harbour CAMs as a result of the replicative aging process. Hence endometriotic lesions, irrespective of subtype, if left intact, would generate CAMs as part of replicative aging, oxidative stress and perhaps other factors yet to be identified and, in some rare cases, develop cancer. The published data still are unable to paint a clear picture on pathogenesis of endometriosis. However, since endometriotic epithelial cells have a higher turnover than their stromal counterpart due to cyclic bleeding, and since the endometriotic stromal component can be formed by refresh influx of mesenchymal cells through epithelial-mesenchymal transition, endothelial-mesenchymal transition, mesothelial-mesenchymal transition and other processes as well as recruitment of bone-marrow-derived stem cells and outflow due to smooth muscle metaplasia, endometriotic epithelial cells have much higher mutation frequencies than their stromal counterpart. The epithelial and stromal cellular components develop in a dependent and co-evolving manner. Genes involved in CAMs are likely to be active players in lesional fibrogenesis, and hyperestrogenism and oxidative stress are likely drivers of both CAMs and fibrogenesis. Finally, endometriotic lesions harbouring CAMs would conceivably be more refractory to medical treatment, due, in no small part, to their high fibrotic content and reduced vascularity and cellularity.

WIDER IMPLICATIONS

The accumulating data on CAMs in endometriosis have shed new light on the pathogenesis and pathophysiology of endometriosis. They also suggest new challenges in management. The distinct yet co-evolving developmental trajectories of endometriotic stroma and epithelium underscore the importance of the lesional microenvironment and ever-changing cellular identity. Mutational profiling of normal endometrium from women of different ages and reproductive history is needed in order to gain a deeper understanding of the pathogenesis. Moreover, one area that has conspicuously received scant attention is the epigenetic landscape of ectopic, eutopic and normal endometrium.

The Genetic Background of Endometriosis: Can ESR2 and CYP19A1 Genes Be a Potential Risk Factor for Its Development?

Endometriosis is defined as the presence of endometrial foci, localized beyond their primary site, i.e., the uterine cavity. The etiology of this disease is rather complex. Its development is supported by hormonal, immunological, and environmental factors. During recent years, particular attention has been focused on the genetic mechanisms that may be of particular significance for the increased incidence rates of endometriosis. According to most recent studies, ESR2 and CYP19A1 genes may account for the potential risk factors of infertility associated with endometriosis. The paper presents a thorough review of the latest reports and data concerning the genetic background of the risk for endometriosis development.

Discovery of heterocycle-containing α-naphthoflavone derivatives as water-soluble, highly potent and selective CYP1B1 inhibitors

Cytochrome P450 1B1 (CYP1B1) has been well validated as an attractive target for cancer prevention and drug resistance reversal. In continuation of our interest in this area, herein, a set of forty-six 6,7,10-trimethoxy-α-naphthoflavone derivatives varying in B ring was synthesized and screened against CYP1 enzymes, leading to the identification of fluorine-containing compound 15i as the most potent and selective CYP1B1 inhibitor (IC₅₀ value of 0.07 nM), being 84-fold more potent than that of the template molecule ANF. Alternatively, the amino-substituted derivative 13h not only possessed a potent inhibitory effect on CYP1B1 (IC₅₀ value of 0.98 nM), but also had a substantially increased water solubility as compared with the lead ANF (311 μg/mL for 13h and <5 μg/mL for ANF). The current study expanded the structural diversity of CYP1B1 inhibitors, and compound 13h could be considered as a promising starting point with great potential for further studies.

Polymorphisms in the 3'UTR Region of ESR2 and CYP19A1 Genes in Women With Endometriosis

OBJECTIVE

ESR2 and CYP19A1 genes play a major role in the hormonal control of women with endometriosis. The aim of the study was to analyze single nucleotide polymorphisms (SNPs) in the 3'UTR region of ESR2 and CYP19A1 genes. The study aimed at localisation of new polymorphisms, the nucleotide variants of which determine the level of susceptibility to endometriosis.

STUDY DESIGN

The study included n = 200 patients: 100 with endometriosis and 100 healthy controls. The Sanger's sequencing method was applied for polymorphism analysis.

RESULTS

Statistically significant correlations were identified between new, not previously described, two SNPs of ESR2 gene and endometriosis: rs4986938 (G>A) and rs928554 (A>G). In the case of rs4986938 polymorphism, the genotype AA was found to decrease the risk of endometriosis (OR = 0.24 95 % PU 0.05-1.22, p = 0.04). Analysis of the rs928554 polymorphism revealed that the occurrence of the AG genotype reduced the risk of endometriosis (OR = 0.38 95 % PU 0.21-0.71, p = 0.002). There were no differences in the distribution of genotypes of the polymorphisms rs10046 (C>T) and rs4646 (C>A) of CYP19A1 gene between patients and control.

CONCLUSIONS

Further studies are necessary in groups with higher numbers of patients to explain whether the above-mentioned polymorphisms may be the risk factors for endometriosis.

The Effect of Rutin and Extracts of Uncaria guianensis (Aubl.) J. F. Gmeland on Primary Endometriotic Cells: A 2D and 3D Study

There is increasing interest in the potential of natural compounds to treat diseases, such as endometriosis, a gynecological disorder that affects 10–15% of women of reproductive age, and it is related to severe pelvic pain and infertility. We have evaluated the in vitro effects of rutin and the aqueous bark, roots, and leaf extracts (ABE, ARE, and ALE, respectively) and isolated components of Uncaria guianensis on stromal cells from eutopic endometrium and lesions of patients with endometriosis. Two- and three-dimensional cultures were used to assess the cell death and production of reactive oxygen species (ROS), cytokines and growth factors of cells following exposure to these natural products. The applied treatments did not reduce cellular viability, but ROS production did increase. In addition, significant increases in the levels of interleukin (IL)-15, IL-17A, IL-4, IL-6, tumor necrosis factor-α, and vascular endothelium growth factor were observed when 2D-cells from endometrium of patients with endometriosis were treated with ABE, while exposure to ALE induced significant increases in epidermal growth factor in lesion cells.

A kaempferol-3-O-β-d-glucoside, intervention effect of astragalin on estradiol metabolism

Kaempherol-3-O-β-d-glucoside, known as astragalin, is one of flavonoids found in a variety of plants including Cuscuta australis R.Br. In recent studies, astragalin possess many biological functions. Although astragalin is formed by linking glucose to kaempherol, its biological activity is not the same as kaempferol. In vivo, 17 β-estradiol (E2) is hydroxylated by cytochrome P450 (CYP) 1B1 to form 4-hydroxy-E2 (4-OH-E2). This metabolite 4-OH-E2 is highly expressed in tumor tissues and has a strong tumorigenic effect. In this paper, the inhibition of astragalin and kaempferol on the activity of cytochrome 1B1 catalyzing estradiol to form 4-hydroxy-estradiol was studied, and the structure-activity relationship between astragalin and kaempferol due to their structural differences was discussed. This study showed that astragalin could inhibit the activity of CYP1B1. The inhibitory effect of astragalin (IC50 5.36 ± 1.13 μM) was weaker than kaempferol (IC50 0.45 ± 0.11 μM). For astragalin, Ki and Vmax values were 4.061 ± 0.737 μM and 1.457 pmol/μg protein/min, while for kaempferol, Ki and Vmax values were 2.631 ± 0.381 μM protein/min and 1.023 ± 0.231 pmol/μg. By kinetic analysis, astragalin and kaempferol were all mixed inhibition, indicating that although astragalin is formed by linking glucose to kaempherol, its inhibitory mechanism on CYP1B1 remained unchanged, and still belonged to a mixed inhibition. The data indicated that astragalin has been able to inhibit the metabolism of estradiol into the carcinogenic metabolite 4-hydroxyl-estradiol in vivo and illustrated an anti-tumor mechanism of astragalin. This study helps to reveal the structure-activity relationship between CYP1B1 activity and its inhibitors.

Bisphenol A affects estradiol metabolism by targeting CYP1A1 and CYP19A1 in human placental JEG-3 cells

Estradiol, in some way or another, plays a critically important physiologic role in the establishment and maintenance of pregnancy. This study was designed to investigate whether BPA affects the estradiol level of human placental JEG-3 cells, which may contribute to insights into the reproductive toxicity and endocrine disruption of BPA. The JEG-3 cells were treated with increasing concentrations of BPA (0.1 to 50 μM). We observed that BPA significantly reduced estradiol level of JEG-3 cells in a dose-dependent manner, which was accompanied by an increase in CYP1A1 protein level and an inhibition of CYP19A1 protein level. Additionally, by lentiviral transduction, we determined that estradiol level of JEG-3 cells over-expressing CYP1A1 gene was notably decreased and the decrease was of 84.9% compared to the control. Meanwhile, estradiol was almost undetectable in CYP19A1 knockdown group. On the contrary, the group with over-expression of CYP19A1 gene increased estradiol level by 8.6 fold while the CYP1A1 knockdown group increased by 5.6 fold. In summary, our research clearly showed that BPA alters JEG-3 estradiol synthesis and catabolism due to its action on CYP1A1 and CYP19A1 protein levels and may interfere with the normal process of placenta formation and embryonic development during early pregnancy.

Endometriosis Pathoetiology and Pathophysiology: Roles of Vitamin A, Estrogen, Immunity, Adipocytes, Gut Microbiome and Melatonergic Pathway on Mitochondria Regulation

Endometriosis is a common, often painful, condition that has significant implications for a woman’s fertility. Classically, endometriosis has been conceptualized as a local estrogen-mediated uterine condition driven by retrograde menstruation. However, recent work suggests that endometriosis may be a systemic condition modulated, if not driven, by prenatal processes. Although a diverse array of factors have been associated with endometriosis pathophysiology, recent data indicate that the low body mass index and decreased adipogenesis may be indicative of an early developmental etiology with alterations in metabolic function crucial to endometriosis pathoetiology.

The present article reviews the data on the pathoetiology and pathophysiology of endometriosis, suggesting key roles for alterations in mitochondria functioning across a number of cell types and body systems, including the immune system and gut microbiome. These changes are importantly regulated by decreases in vitamin A and its retinoic acid metabolites as well as increases in mitochondria estrogen receptor-beta and the N-acetylserotonin/melatonin ratio across development. This has treatment and future research implications for this still poorly managed condition, as well as for the association of endometriosis with a number of cancers.

Epithelial Mutations in Endometriosis: Link to Ovarian Cancer

Epidemiologic and histopathologic associations between endometriosis and epithelial ovarian cancer have been reported; however, the underlying molecular and cellular mechanisms are not well understood. A possible genetic link has been suggested in recent publications. Driver mutations in PIK3CA, KRAS, ARID1A, and other genes have been found in the epithelium of intrauterine endometrial tissue, ovarian and extraovarian pelvic endometriosis tissue, ovarian cancers associated with endometriosis (i.e., clear cell and endometrioid type), and other epithelial ovarian cancers. This makes sense because pelvic endometriosis occurs primarily as a result of retrograde menstruation and implantation of endometrial tissue fragments in ovarian inclusion cysts or extraovarian peritoneal or subperitoneal sites. Unlike epithelial cells, endometriotic stromal cells are mutation free but contain widespread epigenetic defects that alter gene expression and induce a progesterone-resistant and intensely inflammatory environment, driven by estrogen via estrogen receptor-β. The resulting increased estrogenic action in the stroma drives inflammation and sends paracrine signals to neighboring epithelial cells to enhance proliferation. In addition, massively high concentrations of estrogen in the ovary may exert an additional and direct genotoxic effect on DNA and cause accumulation of additional mutations and malignant transformation in initially mutated endometriotic epithelial cells in an ovarian endometrioma, which may initiate epithelial ovarian cancer. The same epithelial mutations and inflammatory processes in stroma are seen in extraovarian deep-infiltrating endometriosis, but carcinogenesis does not occur. We provide a focused review of the literature and discuss the implications of recent genetic breakthroughs linking endometriosis and ovarian cancer.

Intracrine Regulation of Estrogen and Other Sex Steroid Levels in Endometrium and Non-gynecological Tissues; Pathology, Physiology, and Drug Discovery

Our understanding of the intracrine (or local) regulation of estrogen and other steroid synthesis and degradation expanded in the last decades, also thanks to recent technological advances in chromatography mass-spectrometry. Estrogen responsive tissues and organs are not passive receivers of the pool of steroids present in the blood but they can actively modify the intra-tissue steroid concentrations. This allows fine-tuning the exposure of responsive tissues and organs to estrogens and other steroids in order to best respond to the physiological needs of each specific organ. Deviations in such intracrine control can lead to unbalanced steroid hormone exposure and disturbances. Through a systematic bibliographic search on the expression of the intracrine enzymes in various tissues, this review gives an up-to-date view of the intracrine estrogen metabolisms, and to a lesser extent that of progestogens and androgens, in the lower female genital tract, including the physiological control of endometrial functions, receptivity, menopausal status and related pathological conditions. An overview of the intracrine regulation in extra gynecological tissues such as the lungs, gastrointestinal tract, brain, colon and bone is given. Current therapeutic approaches aimed at interfering with these metabolisms and future perspectives are discussed.

Identification of LINC01279 as a cell cycle‑associated long non‑coding RNA in endometriosis with GBA analysis

Endometriosis affects 6‑10% of women of reproductive age. Though a significant amount of research has explored the pathogenesis of endometriosis, little is clear. Elucidating the mechanisms is urgently required for improving the therapeutic efficiency of endometriosis treatment. Long non‑coding RNAs (lncRNAs) have recently acquired extensive attention as regulatory components in a variety of biological processes and diseases. However, the functions of many lncRNAs in endometriosis are poorly understood. Therefore, the exploration of the dysregulated genes in endometriosis, particularly lncRNAs, is of importance. In the present study, datasets for endometriosis, including GSE7305, GSE7846, GSE29981 and E‑MTAB‑694, were downloaded from Gene Expression Omnibus and ArrayExpress. Then, the limma and Affy packages were used to analyze the CEL file. The RankProd method was used to conduct meta‑analysis. Long intergenic non‑protein coding RNA 1279 (LINC01279) was significantly upregulated in the three datasets, and was the most upregulated lncRNA as determined by the RankProd method. Gene set enrichment and Gene Ontology analyses were conducted, which revealed that LINC01279 is likely to function as a cell cycle mediator in endometriosis. Finally, it was identified that LINC01279 is strongly associated with certain previously identified key factors in the development of endometriosis, including cyclin‑dependent kinase 14 and C‑X‑C motif chemokine ligand 12. Thus, it was demonstrated that LINC01279 may be associated with the pathogenesis of endometriosis. This may potentially represent a target in the therapy of endometriosis.

SULFATION PATHWAYS: Contribution of intracrine oestrogens to the aetiology of endometriosis

Endometriosis is an incurable hormone-dependent inflammatory disease that causes chronic pelvic pain and infertility characterized by implantation and growth of endometrial tissue outside the uterine cavity. Symptoms have a major impact on the quality of life of patients resulting in socioeconomic, physical and psychological burdens. Although the immune system and environmental factors may play a role in the aetiology of endometriosis, oestrogen dependency is still considered a hallmark of the disorder. The impact of oestrogens such as oestrone and particularly, oestradiol, on the endometrium or endometriotic lesions may be mediated by steroids originating from ovarian steroidogenesis or local intra-tissue production (intracrinology) dependent upon the expression and activity of enzymes that regulate oestrogen biosynthesis and metabolism. Two key pathways have been implicated: while there is contradictory data on the participation of the aromatase enzyme (encoded by CYP19A1), there is increasing evidence that the steroid sulphatase pathway plays a role in both the aetiology and pathology of endometriosis. In this review, we consider the evidence related to the pathways leading to oestrogen accumulation in endometriotic lesions and how this might inform the development of new therapeutic strategies to treat endometriosis without causing the undesirable side effects of current regimes that suppress ovarian hormone production.

Depleted lamin B1: a possible marker of the involvement of senescence in endometriosis?

PROPOSE

Endometriosis is a benign disease characterized by implantation and the growth of endometrial tissue outside the uterine cavity and it shares similarities with cancer. Lamin B1, p16 and p21 play a role on cell cycle regulation, development, cell repair and its activities are related to cancers. Considering the similarities between endometriosis and cancer, the aim of the present cross-sectional study is to detect p16, p21 and Lamin B1 in the ectopic endometrium of patients with endometriosis (n = 8) with eutopic (n = 8) and control endometrium (n = 8) and relate them to the maintenance and development of endometriosis.

METHODS

Biopsies were obtained from both eutopic and ectopic, from deep infiltrating lesions, endometrium frozen and used for immunofluorescent (p16) or immunohistochemistry procedures (p16, p21, lamin B1).

RESULTS

Detected higher lamin B1 in the eutopic endometrium when compared with ectopic endometrium, with no differences between endometriosis tissue with control endometrium. Similar presence of p16 in all groups of patients and no p21 detection was observed.

CONCLUSION

We observed reduced detection of lamin B1 in the ectopic endometrium raising the possibility that the presence of senescent cells might be contributing to the maintenance and progression of endometriosis by apoptosis resistance and peritoneal stress inherent of the disease.

Enhanced UGT1A1 Gene and Protein Expression in Endometriotic Lesions

The cellular function in endometriosis lesions depends on a highly estrogenic milieu. Lately, it is becoming evident that, besides the circulating levels of estrogens, the balance of synthesis versus inactivation (metabolism) of estrogens by intralesion steroid-metabolizing enzymes also determines the local net estrogen availability. In order to extend the knowledge of the role of estrogen-metabolizing enzymes in endometriosis, we investigated the gene and protein expression of a key uridine diphospho-glucuronosyltransferase (UGT) for estrogen glucuronidation, UGT1A1, in eutopic endometrial samples obtained from nonaffected and endometriosis-affected women and also from endometriotic lesions. Although UGT1A1 messenger RNA (mRNA) expression was detected at similar frequencies in endometriotic lesions and in eutopic endometrial samples, the levels of mRNA expression were greater in deep-infiltrating endometriotic lesions and in non-deep-infiltrating lesions when compared with either control endometrium or eutopic endometrium from women with endometriosis. Overall, we observed that protein expression of UGT1A1 was significantly more frequent in samples from endometriotic lesions in comparison with endometria. In addition, expression of UGT1A1 protein was greater in deep-infiltrating than in non-deep-infiltrating endometriotic lesions. We suggest that the finding of increased expression of UGT1A1 in lesions versus endometria might be related to impairment of regulatory mechanisms, in response to a highly estrogenic milieu, and that this enzyme may be a new target for therapy.

Structural-functional adaptations of porcine CYP1A1 to metabolize polychlorinated dibenzo-p-dioxins

Polychlorinated dibenzo-p-dioxins (PCDDs) are widespread by-products of human industrial activity. They accumulate in tissues of animals and humans, exerting numerous adverse effects on different systems. In living organisms, dioxins are metabolized by enzymes of the cytochrome P450 family, including CYP1A1. Particular dioxin congeners differ in their toxicity level and ability to undergo biodegradation. Since the molecular mechanisms underlying dioxin susceptibility or resistance to biodegradation are unknown, in the present study the molecular interactions between five selected dioxins and porcine CYP1A1 protein were investigated. It was found that the ability of a dioxin to undergo CYP1A1-mediated degradation is associated mainly with the number and position of chlorine atoms in the dioxin molecule. Among all examined congeners, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) demonstrated the highest affinity to CYP1A1 and, at the same time, the greatest distance to the active site of the enzyme. Interestingly, in contrast to other dioxins, the binding of the TCDD molecule to the porcine CYP1A1 active site resulted in a rapid and continuous closure of substrate channels. All the information may help to explain the extended half-life of TCDD in living organisms as well as its high toxicity.

Is cytochrome P450 3A4 regulated by menstrual cycle hormones in control endometrium and endometriosis?

The estrogen-metabolizing activities of cytochrome P450 (CYP) enzymes have been implicated in endometriosis. However, their regulation in various sources of endometrial tissue under different hormonal conditions has not been clarified. Our objective was to study the hormone regulation of a specific CYP enzyme, namely CYP3A4, in control (n = 15) and endometriosis patients (n = 42). To this end, we evaluated mRNA expression (using real-time PCR) of CYP3A4 in tissue samples classified according to the phase of menstrual cycle at which they were obtained as confirmed by the related circulating hormone levels. Protein expression was also evaluated by Western Blot. In order to further investigate the hormonal regulation of CYP3A4, stromal cells from ovarian endometriotic lesions were cultured with the prevailing hormones of the distinct phases of the menstrual cycle. We observed that all control and endometriosis tissues express CYP3A4. Nevertheless, changes in CYP3A4 gene expression related to cycle phase were only seen in the control eutopic endometrium and not in samples from endometriosis patients, with an increase in the luteal phase. Stromal cells isolated from ovarian endometriotic lesions expressed CYP3A4 and their exposure to luteal phase-mimicking hormones (estradiol + progesterone) reduced CYP3A4 mRNA in parallel with a diminished expression of the corresponding receptors, estrogen receptor alpha and progesterone receptor. Our findings suggest that steroid hormones are able to regulate CYP3A4 mRNA expression, although the circulating levels of these hormones can only regulate control endometrium and not endometriosis tissues, probably because of dysregulated local steroid concentration in these latter samples.

Activin A Stimulates Aromatase via the ALK4-Smad Pathway in Endometriosis

Endometriosis is an estrogen-dependent disease. We previously found that the expression of Activin A was upregulated in the peritoneal fluid of patients with endometriosis. The results of the present study indicated that Activin A induced estradiol secretion and P450arom expression in endometrial stromal cells (ESCs) derived from endometriosis patients. The mechanism of estrogenic synthesis was regulated by the Activin-Smad pathway in endometrial lesions. The data showed that the effect of Activin A on ESCs was partially abrogated by pretreatment with an inhibitor of ALK4 (the type I receptor, ActRIB) and Smad4-siRNA. Cumulatively, these data suggest that Activin A promotes the secretion of estradiol from ESCs by increasing the expression of P450arom via the ALK4-Smad pathway. These findings indicate the ALK4-Smad pathway may promote ectopic lesion survival and development.