Role of Cyclins and Cytoskeletal Proteins in Endometriosis: Insights into Pathophysiology

Endometriosis is a gynecological condition where endometrium-like tissue grows outside the uterus, posing challenges in understanding and treatment. This article delves into the deep cellular and molecular processes underlying endometriosis, with a focus on the crucial roles played by cyclins and cytoskeletal proteins in its pathogenesis, particularly in the context of Epithelial-Mesenchymal Transition (EMT). The investigation begins by examining the activities of cyclins, elucidating their diverse biological roles such as cell cycle control, proliferation, evasion of apoptosis, and angiogenesis among ectopic endometrial cells. A comprehensive analysis of cytoskeletal proteins follows, emphasizing their fundamental biological roles and their specific significance to endometriotic cell features. This review sheds light on the interconnected pathways through which cyclins and cytoskeletal proteins converge, contributing to the genesis and progression of endometriosis. Understanding these molecular complexities not only provides insight into the underlying causes of the disease but also holds promise for the development of specific therapeutic approaches, ushering in a new era in the management of this devastating disorder.

Overexpression of lncRNA-MEG3 inhibits endometrial cell proliferation and invasion via miR-21-5p/DNMT3B/Twist

Recent studies have found that lncRNA-MEG3(MEG3) plays an important role in the development of EMs (Endometriosis), but the specific mechanism needs to be further explored. This study aimed to investigate the effect of MEG3 on the proliferation, invasion of EMs cells. The authors used RT-qPCR to detect the expression of MEG3 and miR-21-5p in EMs tissues and hESCs cells, MTT and Transwell to detect cell proliferation and invasion, western blotting assay to detect the expression of DNMT3B and Twist, MSP to detect the methylation of Twist. The present study's detection results showed that MEG3 was lowly expressed in EMs tissues and hESCs cells, and overexpression of MEG3 could down-regulate miR-21-5p and inhibit endometrial cell proliferation and invasion. In addition, overexpression of MEG3 upregulated the expression of DNMT3B and promoted the methylation of TWIST. In conclusion, the present findings suggest that MEG3 is downregulated in EMs tissues, and overexpression of MEG3 can promote the activity of DNA methyltransferase DNMT3B by downregulating miR-21-5p, thereby promoting the methylation of Twist, downregulating Twist level to inhibits hESCs cells proliferation and invasion.

Dienogest May Reduce Estradiol- and Inflammatory Cytokine-Induced Cell Viability and Proliferation and Inhibit the Pathogenesis of Endometriosis: A Cell Culture- and Mouse Model-Based Study

Dienogest (DNG) is a therapeutic medication used in endometriosis treatment. Limited data are available regarding its mechanism of action on endometrial cells. Using in vivo and in vitro models, we investigated whether DNG treatment causes significant biological changes in human endometrial stromal cells (ESCs). The markers related to the pathogenesis of endometriosis in ESCs were evaluated using estradiol, tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), and IL-32, administered alone or in combination with DNG. Implanted endometrial tissues were compared between C57BL/6 mice that did or did not receive DNG treatment by using size measurements and immunohistochemistry. A significant decrease in cell viability, protein kinase B (AKT) phosphorylation, and the expression of p21-activated kinase 4 and vascular endothelial growth factor were observed in ESCs treated with estradiol plus DNG. Cell viability, AKT phosphorylation, and proliferating cell nuclear antigen (PCNA) expression also decreased significantly after TNF-α plus DNG treatment. Treatment with IL-1β or IL-32 plus DNG significantly decreased cell viability or PCNA expression, respectively. The size of the implanted endometrial tissue significantly decreased in mice treated with DNG, accompanied by decreased PCNA expression. Thus, DNG may reduce cell viability and proliferation induced by estradiol, TNF-α, IL-1β, and IL-32, and inhibit the endometriosis pathogenesis by decreasing PCNA expression.

microRNA-141 inhibits TGF-β1-induced epithelial-to-mesenchymal transition through inhibition of the TGF-β1/SMAD2 signalling pathway in endometriosis

PURPOSE

Recent studies have demonstrated the differential expression of micro(mi)RNAs in endometriosis. Previously, we reported the low expression of miR-141 in patients with this disease. Epithelial-to-mesenchymal transition (EMT) and the transforming growth factor-beta1 (TGF-β1)-induced SMAD2 signalling pathway are central to tumour proliferation and invasion. However, the role of miR-141 in regulating the TGF-β1/SMAD2 signalling pathway and the associated EMT to be elucidated.

METHODS

The levels of TGF-β1/SMAD2 signalling and EMT markers expression in eutopic and ectopic endometria of endometriosis were determined by immunohistochemistry and western blot analyses. MiR-141 expression was analysed by quantitative reverse-transcription polymerase chain reaction. Cellular invasion and proliferation were determined by transwell and CCK-8 assays, respectively. Functional assay of miR-141 was performed using plasmid and shRNA transfection methods.

RESULT

The presence of miR-141, EMT, and TGF-β1/SMAD2 signalling markers were detected in eutopic and ectopic endometria of endometriosis. TGF-β1-induced EMT in Ishikawa (ISK) cells by activating the SMAD2 signalling pathway, whereas miR-141 inhibited the TGF-β1-induced EMT, proliferation and invasion abilities of these cells.

CONCLUSION

These data identify miR-141 as a novel driver of EMT in endometriosis, implicates the link between miR-141 and TGF-β1/SMAD2 signalling pathway in the context of endometriosis, and underscore the role of EMT in the development of endometriosis.

Decreased expression of cell polarity protein Scribble correlated with altered subcellular localization of the Crumbs homologue 3 protein in human adenomyotic endometrial cells

AIM

Previous studies have revealed that loss of cell apical-basal polarity contributed to the early stages of tumorigenesis. Adenomyosis involves a down-growth and aberrant implantation of the endometrial basalis into the myometrium. This study discovered aberrant expression of polarity protein Scribble (Scrib) and Crumbs homologue 3 protein (CRB3) in epithelial cells of diffuse adenomyosis.

METHODS

This was a case-controlled study, including 39 patients with histologic evidence of adenomyosis, and 48 patients with carcinoma in situ of the uterine cervix without adenomyosis or endometriosis as control. Adenomyotic foci, eutopic endometrium of adenomyotic patients as well as normal endometrium were collected. Reverse Transcription Polymerase Chain Reaction (RT-PCR), Immunoreactivity, confocal microscopy and immune electron microscopy were conducted to evaluate Scribble expression and localization of Scribble and CRB3.

RESULTS

Scrib was screen out as an abnormally expressed polarity protein in adenomyotic eutopic endometrium (ADM-EU) at messenger RNA (mRNA) level. The ADM-EU and adenomyotic ectopic endometrium showed a significantly decreased expression of Scrib compared with normal endometrium (all P-values <0.05). Scrib decreased significantly in ADM-EU than normal endometrium only in patients at proliferative phase and with severe dysmenorrhea (P-values <0.01, P-values <0.001 respectively). In ADM-EU, Scrib expression significantly lowered in patients with severe dysmenorrhea than mild dysmenorrhea (P-values <0.05). Aberrant redistribution of CRB3 from apical to basal lateral membrane portion was also detected in experiments by confocal microscopy immune electron microscopy (all P-values <0.01).

CONCLUSION

Basolateral polarity protein Scrib was found decreased significantly in endometrial cells of adenomyosis at mRNA and protein level, compared with normal endometrium. Menstrual phase and severity of dysmenorrhea has an impact on Scrib expression. Scrib decrease was accompanied by aberrant redistribution of CRB3 from apical to basal lateral membrane portion.

Role of interleukin-32 in the pathogenesis of endometriosis: in vitro, human and transgenic mouse data

STUDY QUESTION

Does interleukin-32 (IL-32) play a role in the pathogenesis of endometriosis?

SUMMARY ANSWER

IL-32 might be involved in the pathogenesis of endometriosis through increased viability, proliferation and invasion of endometrial cells.

WHAT IS KNOWN ALREADY

Endometriosis is characterized as a chronic inflammatory disease and several proinflammatory cytokines are suggested to be involved in its pathogenesis and pathophysiology. IL-32, recognized as a new proinflammatory cytokine and a strong inducer of other proinflammatory cytokines, has been shown to serve as a key modulator in several chronic inflammatory diseases.

STUDY DESIGN, SIZE, DURATION

This study included comparison of IL-32 levels in the peritoneal fluids between women with and without endometriosis, in-vitro experiments using Ishikawa cells and endometrial stromal cells (ESCs), and experiments on IL-32 transgenic mice and wild-type mice with induced endometriosis.

PARTICIPANTS/MATERIALS, SETTING, METHODS

IL-32 levels in the peritoneal fluids were measured using enzyme-linked immunosorbent assays. Cell viability, expression of proliferating cell nuclear antigen (PCNA), and cellular invasiveness were analyzed following in-vitro treatment of Ishikawa cells and ESCs with recombinant IL-32 alpha (α) and gamma (γ). Ectopic endometriotic lesions were compared between IL-32 transgenic mice and wild-type mice after autologous endometrial transplantation with immunohistochemistry for Ki-67 antigen and PCNA.

MAIN RESULTS AND THE ROLE OF CHANCE

The peritoneal fluid concentration of IL-32 was significantly higher in patients with advanced stage endometriosis compared with the controls. In-vitro treatment with IL-32 α and γ caused significant increases in cellular viability, PCNA expression, and invasiveness in Ishikawa cells and ESCs. The IL-32 transgenic mice had a significantly larger size of the ectopic endometrial lesions with higher expression of Ki-67 antigen and PCNA compared with wild-type mice.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

It is still unclear whether IL-32 is a main regulator, or one of several downstream proinflammatory cytokines, causing establishment and/or progression of endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

Further investigation on IL-32 signaling pathways may contribute to development a more effective treatment of endometriosis.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (Grant number: HI16C1682). None of the authors has anything to disclose.

Bone marrow-derived cells or C-X-C motif chemokine 12 (CXCL12) treatment improve thin endometrium in a mouse model

Successful implantation and pregnancy is dependent on sufficient endometrial growth during each reproductive cycle. Here, we report the therapeutic effect of either bone marrow-derived cells (BMDCs) or the stem cell chemo-attractant C-X-C motif chemokine 12 (CXCL12) on endometrial receptivity in a murine ethanol induced thin endometrium model. Endometrial epithelial area was significantly increased in mice treated with BMDCs, CXCL12, or by co-treatment with both compared with PBS-treated controls. Ki-67 and CD31 immunoreactivity was significantly higher in mice treated with either BMDCs, CXCL12, or both. The mRNA expression levels of endometrial receptivity markers leukemia inhibitory factor, interleukin-1β, and integrin beta-3 were increased in mice treated with either BMDCs, CXCL12, or both. The mRNA levels of matrix metalloproteinase-2 and -9 were significantly decreased by BMDCs but not by CXCL12. Pregnancy rates and litter size were increased after either treatment. Both BMDCs and CXCL12 displayed a comparable efficacy on endometrial regeneration in mice with thin endometrium. Our findings indicate the potential therapeutic effects of BMDCs and CXCL12 on infertility related to thin endometrium. Bone marrow-derived cells and CXCL12 displayed a comparable efficacy on endometrial regeneration in mice with thin endometrium.

P21-Activated Kinase 1 Overactivates in Eutopic Endometrium of Adenomyosis

Adenomyosis is a common gynecological disease, characterized by the existence of endometrium in the myometrium. The pathogenesis of adenomyosis is not fully understood. P21-activated kinase 1 (PAK1) is an effector of small Rho GTPases including CDC42 and RAC1 and plays various roles in cellular biology, especially cytoskeletal remodeling. This study aimed to evaluate whether the expression and activation of PAK1 in adenomyosis were different from normal. Immunohistochemistry was performed to evaluate the expression of PAK1 and its active form phosphorylated-PAK1 (pPAK1) semi-quantitatively in women with and without adenomyosis. Immunofluorescence was performed to locate the distribution of pPAK1. This study found that PAK1 in eutopic endometrium of adenomyosis was overactivated compared to normal. Phosphorylated-PAK1 assembled along the apical surface of glandular cell membrane. In ectopic lesions, PAK1 expression decreased and its activation returned to the baseline. The expression of pPAK1 correlated with the frequency of reproduction. These findings suggest that PAK1 overactivation in the endometrium may be an important event during the development of adenomyosis, meanwhile, decreased phosphorylation may assist to form lesions.

Effects of Di-(2-ethylhexyl) Phthalate on the Hypothalamus-Uterus in Pubertal Female Rats

The pollution of endocrine disruptors and its impact on human reproductive system have attracted much attention. Di-(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, is widely used in food packages, containers, medical supplies and children's toys. It can cause diseases such as infertility, sexual precocity and uterine bleeding and thus arouse concerns from the society and scholars. The effect of DEHP on pubertal female reproductive system is still not well-studied. This study was to investigate the effects of DEHP on the hypothalamus-uterus in pubertal female rats, reveal the reproductive toxicity of DEHP on pubertal female rats and its mechanism, and provide scientific evidence for the evaluation of toxicity and toxic mechanism of DEHP on reproductive system. Forty-eight pubertal female rats were randomly divided into four groups and respectively administered via oral gavage 0, 250, 500, or 1000 mg/kg/d DEHP in 0.1 mL corn oil/20 g body weight for up to four weeks. Compared with control rats, the DEHP-treated rats showed: (1) higher gonadotropin-releasing hormone (GnRH) level in the hypothalamus; (2) higher protein levels of GnRH in the hypothalamus; and (3) higher mRNA and protein levels of GnRH receptor (GnRHR) in the uterus. Our data reveal that DEHP exposure may lead to a disruption in pubertal female rats and an imbalance of hypothalamus-uterus. Meanwhile, DEHP may, through the GnRH in the hypothalamus and its receptor on the uterus, lead to diseases of the uterus. DEHP may impose a negative influence on the development and functioning of the reproductive system in pubertal female rats.

Decreased Progesterone Receptor B/A Ratio in Endometrial Cells by Tumor Necrosis Factor-Alpha and Peritoneal Fluid from Patients with Endometriosis

PURPOSE

Progesterone resistance is thought to be a major factor that contributes to progression of endometriosis. However, it is not clear what causes progesterone resistance in endometriosis. This study aimed to assess whether cytokines or peritoneal fluid can affect progesterone receptor (PR) expression in endometrial cells and to verify whether PR expression is reduced in endometriosis.

MATERIALS AND METHODS

The PR-B/A ratio was measured via real-time polymerase chain reaction after in vitro culture, in which endometrial cells were treated with either tumor necrosis factor-alpha (TNF-α), interleukin-1 beta, or peritoneal fluid obtained from women with advanced-stage endometriosis. Immunohistochemistry was performed to compare PR-B expression between eutopic and ectopic endometrial tissues from women with and without advanced-stage endometriosis.

RESULTS

The PR-B/A ratio was significantly decreased by treatment with either TNF-α (p=0.011) or peritoneal fluid from women with advanced-stage endometriosis (p=0.027). Immunoreactivity of PR-B expression was significantly lower during the secretory phase than during the proliferative phase in endometrial tissues from control subjects (p<0.001). PR-B expression was significantly reduced in the eutopic endometrium (p=0.031) and ovarian endometrioma (p=0.036) from women with advanced-stage endometriosis compared with eutopic endometrium tissues from control subjects.

CONCLUSION

Progesterone resistance in endometriosis may be caused by proinflammatory conditions in the pelvic peritoneal microenvironment.

Endometrial biomarkers for the non-invasive diagnosis of endometriosis

BACKGROUND

About 10% of reproductive-aged women suffer from endometriosis, which is a costly, chronic disease that causes pelvic pain and subfertility. Laparoscopy is the gold standard diagnostic test for endometriosis, but it is expensive and carries surgical risks. Currently, there are no non-invasive tests available in clinical practice that accurately diagnose endometriosis. This is the first diagnostic test accuracy review of endometrial biomarkers for endometriosis that utilises Cochrane methodologies, providing an update on the rapidly expanding literature in this field.

OBJECTIVES

To determine the diagnostic accuracy of the endometrial biomarkers for pelvic endometriosis, using a surgical diagnosis as the reference standard. We evaluated the tests as replacement tests for diagnostic surgery and as triage tests to inform decisions to undertake surgery for endometriosis.

SEARCH METHODS

We did not restrict the searches to particular study designs, language or publication dates. To identify trials, we searched the following databases: CENTRAL (2015, July), MEDLINE (inception to May 2015), EMBASE (inception to May 2015), CINAHL (inception to April 2015), PsycINFO (inception to April 2015), Web of Science (inception to April 2015), LILACS (inception to April 2015), OAIster (inception to April 2015), TRIP (inception to April 2015) and ClinicalTrials.gov (inception to April 2015). We searched DARE and PubMed databases up to April 2015 to identify reviews and guidelines as sources of references to potentially relevant studies. We also performed searches for papers recently published and not yet indexed in the major databases. The search strategies incorporated words in the title, abstract, text words across the record and the medical subject headings (MeSH).

SELECTION CRITERIA

We considered published peer-reviewed, randomised controlled or cross-sectional studies of any size that included prospectively collected samples from any population of reproductive-aged women suspected of having one or more of the following target conditions: ovarian, peritoneal or deep infiltrating endometriosis (DIE).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from each study and performed a quality assessment. For each endometrial diagnostic test, we classified the data as positive or negative for the surgical detection of endometriosis and calculated the estimates of sensitivity and specificity. We considered two or more tests evaluated in the same cohort as separate data sets. We used the bivariate model to obtain pooled estimates of sensitivity and specificity whenever sufficient data were available. The predetermined criteria for a clinically useful test to replace diagnostic surgery was one with a sensitivity of 94% and a specificity of 79%. The criteria for triage tests were set at sensitivity at or above 95% and specificity at or above 50%, which in case of negative results rules out the diagnosis (SnOUT test) or sensitivity at or above 50% with specificity at or above 95%, which in case of positive result rules in the diagnosis (SpIN test).

MAIN RESULTS

We included 54 studies involving 2729 participants, most of which were of poor methodological quality. The studies evaluated endometrial biomarkers either in specific phases of the menstrual cycle or outside of it, and the studies tested the biomarkers either in menstrual fluid, in whole endometrial tissue or in separate endometrial components. Twenty-seven studies evaluated the diagnostic performance of 22 endometrial biomarkers for endometriosis. These were angiogenesis and growth factors (PROK-1), cell-adhesion molecules (integrins α3β1, α4β1, β1 and α6), DNA-repair molecules (hTERT), endometrial and mitochondrial proteome, hormonal markers (CYP19, 17βHSD2, ER-α, ER-β), inflammatory markers (IL-1R2), myogenic markers (caldesmon, CALD-1), neural markers (PGP 9.5, VIP, CGRP, SP, NPY, NF) and tumour markers (CA-125). Most of these biomarkers were assessed in single studies, whilst only data for PGP 9.5 and CYP19 were available for meta-analysis. These two biomarkers demonstrated significant diversity for the diagnostic estimates between the studies; however, the data were too limited to reliably determine the sources of heterogeneity. The mean sensitivities and specificities of PGP 9.5 (7 studies, 361 women) were 0.96 (95% confidence interval (CI) 0.91 to 1.00) and 0.86 (95% CI 0.70 to 1.00), after excluding one outlier study, and for CYP19 (8 studies, 444 women), they were were 0.77 (95% CI 0.70 to 0.85) and 0.74 (95% CI 0.65 to 84), respectively. We could not statistically evaluate other biomarkers in a meaningful way. An additional 31 studies evaluated 77 biomarkers that showed no evidence of differences in expression levels between the groups of women with and without endometriosis.

AUTHORS' CONCLUSIONS

We could not statistically evaluate most of the biomarkers assessed in this review in a meaningful way. In view of the low quality of most of the included studies, the findings of this review should be interpreted with caution. Although PGP 9.5 met the criteria for a replacement test, it demonstrated considerable inter study heterogeneity in diagnostic estimates, the source of which could not be determined. Several endometrial biomarkers, such as endometrial proteome, 17βHSD2, IL-1R2, caldesmon and other neural markers (VIP, CGRP, SP, NPY and combination of VIP, PGP 9.5 and SP) showed promising evidence of diagnostic accuracy, but there was insufficient or poor quality evidence for any clinical recommendations. Laparoscopy remains the gold standard for the diagnosis of endometriosis, and using any non-invasive tests should only be undertaken in a research setting. We have also identified a number of biomarkers that demonstrated no diagnostic value for endometriosis. We recommend that researchers direct future studies towards biomarkers with high diagnostic potential in good quality diagnostic studies.

Increased expression of nuclear factor kappa-B p65 subunit in adenomyosis

Objective

Nuclear factor kappa-B (NF-κB) is a critical proinflammatory regulator that has been suggested to play a pivotal role in the pathogenesis and pathophysiology of endometriosis. In the present study, we aimed to evaluate whether the expression of NF-κB p65 subunit is increased in the eutopic endometrium and/or in the adenomyosis nodule of women with adenomyosis.

Methods

Thirty-three women with histologically confirmed adenomyosis after laparoscopic or transabdominal hysterectomy were recruited. Women with carcinoma in situ of uterine cervix without evidence of adenomyosis or endometriosis (n=32) served as controls. Formalin-fixed, paraffin-embedded archival tissues were sectioned and immunostained utilizing a monoclonal anti-human NF-κB p65 subunit antibody, and the immunoreactivity of NF-κB p65 subunit was compared between women with and without adenomyosis.

Results

The immunoreactivities of both the nuclear and the cytoplasmic NF-κB p65 subunit were significantly increased in the stromal cells in the eutopic endometrium as well as in the adenomyosis nodule of women with adenomyosis compared with controls, respectively. The nuclear expression of NF-κB p65 subunit was significantly higher in the glandular cells in the eutopic endometrium as well as the adenomyosis nodule of women with adenomyosis compared with controls, respectively.

Conclusion

The expression of NF-κB p65 is increased in the eutopic endometrium and adenomyosis nodule of women with adenomyosis, which strongly suggest that NF-κB plays a critical role in the pathogenesis and/or pathophysiology of adenomyosis.

Possible Role of Phthalate in the Pathogenesis of Endometriosis: In Vitro, Animal, and Human Data

CONTEXT

Although phthalates were shown to have several negative effects on reproductive function in animals, its role in the pathogenesis of endometriosis remains to be elucidated.

OBJECTIVE

We aimed to investigate the in vitro and in vivo effects of di-(2-ethylhexyl)-phthalate (DEHP) and to compare the urinary levels of several phthalate metabolites between women with and without endometriosis.

DESIGN

For experimental studies, we used endometrial cell culture and nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mouse models. We also performed a prospective case-control study for human sample analyses.

SETTING

The study was conducted at an academic center.

MAIN OUTCOME MEASURES

The activities of matrix metalloproteinase (MMP)-2 and 9, cellular invasiveness, phosphorylation of extracellular signal-regulated kinase (Erk), and expression of p21-activated kinase 4 were analyzed in endometrial cells treated with DEHP. The implant size was compared between NOD/SCID mice fed with and without DEHP. Urinary concentrations of several phthalate metabolites were compared between women with and without endometriosis.

RESULTS

In vitro treatment of endometrial cells with DEHP led to significant increases of MMP-2 and 9 activities, cellular invasiveness, Erk phosphorylation, and p21-activated kinase 4 expression. The size of the endometrial implant was significantly larger in the NOD/SCID mice fed with DEHP compared with those fed with vehicle. The urinary concentration of mono (2-ethyl-5-hydroxyhexyl) phthalate, mono (2-ethyl-5-oxohexyl) phthalate, and mono (2-ethyl-5-carboxyphentyl) phthalate were significantly higher in women with endometriosis compared with controls.

CONCLUSION

These findings strongly suggest that exposure to phthalate may lead to establishment of endometriosis by enhancing invasive and proliferative activities of endometrial cells.

p21-Activated Kinases 1, 2 and 4 in Endometrial Cancers: Effects on Clinical Outcomes and Cell Proliferation

p21-activated kinases (Paks) are serine/threonine protein kinases involved in biological events linked to malignant tumor progression. In this study, expression of Pak1, p-Pak2 Ser²⁰, Pak4, pPak4 Ser⁴⁷⁴ in 21 normal endometrium, 16 hyperplastic endometrium without atypia, 17 atypical complex hyperplasia and 67 endometrial cancers was assessed by immunohistochemistry and correlated with clinicopathological parameters. We also accessed the proliferative role and downstream targets of Pak1 in endometrial cancer. Pak1 was expressed in cytoplasm whereas Pak4 and p-Pak4 were expressed in both cytoplasm and nucleus of endometrial tissues. In normal endometrium, significantly higher Pak1 (P = 0.028) and cytoplasmic p-Pak2 (P = 0.048) expression was detected in proliferative endometrium than secretory endometrium. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 was significantly overexpressed in endometrial cancer when compared to atrophic endometrium (all P<0.05). Moreover, type I endometrioid carcinomas showed significantly higher Pak1 expression than type II non-endometrioid carcinomas (P<0.001). On the other hand, Pak1, Pak4 and p-Pak4 expression negatively correlated with histological grade (all P<0.05) while p-Pak2 and cytoplasmic Pak4 expression inversely correlated with myometrial invasion (all P<0.05). Furthermore, patients with endometrial cancers with lower cytoplasmic Pak4 expression showed poorer survival (P = 0.026). Multivariate analysis showed cytoplasmic Pak4 is an independent prognostic factor. Functionally, knockdown of Pak1, but not Pak4, in endometrial cancer cell line led to reduced cell proliferation along with reduced cyclin D1, estrogen receptor (ERα) and progestogen receptor (PR) expression. Significant correlation between Pak1 and PR expression was also detected in clinical samples. Our findings suggest that Pak1 and cytoplasmic p-Pak2 may promote cell proliferation in normal endometrium during menstral cycle. Pak1, cytoplasmic and nuclear Pak4 and nuclear p-Pak4 are involved in the pathogenesis of endometrial cancer especially in postmenopausal women. Pak1 promote endometrial cancer cell proliferation, particular in type I endometrioid carcinoma. Cytoplasmic Pak4 can be potential prognostic marker in endometrial cancer.

Increased expression of p21-activated kinase 4 in adenomyosis and its regulation of matrix metalloproteinase-2 and -9 in endometrial cells

OBJECTIVE

To investigate the expression of p21-activated kinase 4 (Pak4) in both adenomyotic foci and the eutopic endometrium of women with adenomyosis, and whether the activities of matrix metalloproteinases (MMPs)-2 and -9 are regulated by Pak4 in endometrial cells.

DESIGN

Experimental study using human samples and cell lines.

SETTING

University hospital.

PATIENT(S)

Thirty-nine patients with histologic evidence of adenomyosis, and 34 patients with carcinoma in situ of the uterine cervix without adenomyosis or endometriosis.

INTERVENTION(S)

Immunohistochemistry, zymography after transfection with Pak4 small interfering RNA (siRNA), and western blot analyses after nuclear factor kappa-B (NF-кB) inhibitor treatment.

MAIN OUTCOME MEASURE(S)

The Pak4 immunoreactivity of women with vs. without adenomyosis was compared semiquantitatively. The activities of MMP-2 and -9 were analyzed in eutopic endometrial stromal cells and Ishikawa cells after transfection with Pak4 siRNA. The Pak4 expression was evaluated in endometrial cells after treatment with NF-кB inhibitor.

RESULT(S)

Pak4 immunoreactivity was increased in adenomyotic foci and in the eutopic endometrium of women with adenomyosis. Transfection of endometrial cells with Pak4 siRNA led to significant decreases of MMP-2 and -9 activities. In vitro treatment of endometrial cells with tumor necrosis factor-alpha caused a significant increase of NF-кB activation and Pak4 expression, which was obviously decreased by the NF-кB inhibitor pyrrolidinedithiocarbamate.

CONCLUSION(S)

Our results suggest that Pak4 is regulated by NF-кB and that increased Pak4 expression can lead to development of adenomyosis by enhancing the invasiveness of endometrial cells through regulation of MMP-2 and -9 activities.

Oestrogen-induced angiogenesis promotes adenomyosis by activating the Slug-VEGF axis in endometrial epithelial cells

Adenomyosis is an oestrogen-dependent disease characterized by the invasion of endometrial epithelial cells into the myometrium of uterus, and angiogenesis is thought to be required for the implantation of endometrial glandular tissues during the adenomyotic pathogenesis. In this study, we demonstrate that compared with eutopic endometria, adenomyotic lesions exhibited increased vascularity as detected by sonography. Microscopically, the lesions also exhibited an oestrogen-associated elevation of microvascular density and VEGF expression in endometrial epithelial cells. We previously reported that oestrogen-induced Slug expression was critical for endometrial epithelial–mesenchymal transition and development of adenomyosis. Our present studies demonstrated that estradiol (E2) elicited a Slug-VEGF axis in endometrial epithelial cells, and also induced pro-angiogenic activity in vascular endothelial cells. The antagonizing agents against E2 or VEGF suppressed endothelial cells migration and tubal formation. Animal experiments furthermore confirmed that blockage of E2 or VEGF was efficient to attenuate the implantation of adenomyotic lesions. These results highlight the importance of oestrogen-induced angiogenesis in adenomyosis development and provide a potential strategy for treating adenomyosis through intercepting the E2-Slug-VEGF pathway.

Increased nuclear expression of nuclear factor kappa-B p65 subunit in the eutopic endometrium and ovarian endometrioma of women with advanced stage endometriosis

PROBLEM

We evaluated whether the expression of NF-кB p65 subunit is increased in the eutopic endometrium and/or in the ovarian endometrioma of women with advanced stage endometriosis, and ascertained in vitro effects of proinflammatory cytokines on the expression and DNA binding of NF-кB p65 subunit in endometrial cells.

METHOD OF STUDY

Immunohistochemistry was performed to compare the nuclear NF-кB p65 subunit immunoreactivity between women with and without advanced stage endometriosis. The nuclear NF-кB p65 subunit expression and DNA binding were also analyzed in endometrial cells treated with tumor necrosis factor-alpha (TNF-α) or interleukin-1beta (IL-1β) utilizing Western blot analysis, enzyme-linked immunosorbent assay, and electrophoretic mobility shift assay.

RESULTS

The immunoreactivity of the nuclear NF-кB p65 subunit was significantly increased in the eutopic endometrium as well as in the ovarian endometrioma of women with endometriosis compared with the controls. In vitro treatment of endometrial cells with TNF-α and IL-1β led to a significant increase in nuclear NF-кB p65 subunit expression and DNA binding.

CONCLUSIONS

The nuclear expression of NF-κB p65 is increased in the eutopic endometrium and ovarian endometrioma of women with advanced stage endometriosis, which strongly suggests that NF-кB signaling plays a crucial role in the pathogenesis and/or pathophysiology of endometriosis.

Inducers of G-protein coupled estrogen receptor (GPER) in endometriosis: potential implications for macrophages and follicle maturation

Endometriosis is an estrogen dependent chronic inflammation and thus a condition of stress. Though the G-protein coupled estrogen receptor (GPER) has been shown to be up-regulated in ovarian endometriosis, insights involved in inducing this receptor expression are largely elusive. Therefore, this study investigated whether stress-related factors (ACTH, prednisolone) or inflammatory factors (IL-1β, TNFα, and PGE(2)) factors may affect GPER. To further link GPER to endometriosis pathophysiology it was tracked in macrophages and follicles of endometriotic ovaries. This study found GPER expression to be modulated by stress-related hormones as well as inflammation and to be up-regulated in endometriosis-associated macrophages. At the same time, follicles of ovaries affected by endometriosis presented significantly reduced GPER positivity when compared to controls, suggesting a possible way by which endometriosis may affect folliculogenesis. The multiple roles of GPER as presented herein make it a promising future candidate for targeted molecular endometriosis treatment.

Up-regulation of p21-activated kinase 1 by in vitro treatment with interleukin 1-beta and its increased expression in ovarian endometriotic cysts

We evaluated whether the proinflammatory cytokines can regulate p21-activated kinase (Pak1) expression in endometrial cells as well as whether its expression is increased in endometriotic cysts. We found that interleukin-1β up-regulates Pak1 expression in endometrial stromal cells (ESC) and that the immunoreactivity of Pak1 is increased in the endometriotic cysts.

The protein kinase A pathway-regulated transcriptome of endometrial stromal fibroblasts reveals compromised differentiation and persistent proliferative potential in endometriosis

Intrinsic abnormalities in transplanted eutopic endometrium are believed to contribute to the pathogenesis of pelvic endometriosis. Herein we investigated transcriptomic differences in human endometrial stromal fibroblasts (hESFs) from women with (hESF(endo)) vs. without (hESF(nonendo)) endometriosis, in response to activation of the protein kinase A (PKA) pathway with 8-bromoadenosine-cAMP (8-Br-cAMP). hESF(nonendo) (n = 4) and hESF(endo) (n = 4) were isolated from eutopic endometrium and treated +/- 0.5 mm 8-Br-cAMP for 96 h. Purified total RNA was subjected to microarray analysis using the whole-genome Gene 1.0 ST Affymetrix platform. A total of 691 genes were regulated in cAMP-treated hESF(nonendo) vs. 158 genes in hESF(endo), suggesting a blunted response to cAMP/PKA pathway activation in women with disease. Real-time PCR and ELISA validated the decreased expression of decidualization markers in hESF(endo) compared with hESF(nonendo). In the absence of disease, 8-Br-cAMP down-regulated progression through the cell cycle via a decrease in cyclin D1, cyclin-dependent kinase 6, and cell division cycle 2 and an increase in cyclin-dependent kinase inhibitor 1A. However, cell cycle components in hESF(endo) were not responsive to 8-Br-cAMP, resulting in persistence of a proliferative phenotype. hESF(endo) treated with 8-Br-cAMP exhibited altered expression of immune response, extracellular matrix, cytoskeleton, and apoptosis genes. Changes in phosphodiesterase expression and activity were not different among experimental groups. These data support that eutopic hESF(endo) with increased proliferative potential can seed the pelvic cavity via retrograde menstruation and promote establishment, survival, and proliferation of endometriosis lesions, independent of hydrolysis of cAMP and likely due to an inherent abnormality in the PKA pathway.