Characterization of Molecular Changes in Endometrium Associated With Chronic Use of Progesterone Receptor Modulators: Ulipristal Acetate Versus Mifepristone

Targeting delivery of mifepristone to endometrial dysfunctional macrophages for endometriosis therapy

Endometriosis seriously affects 6-10 % of reproductive women globally and poses significant clinical challenges. The process of ectopic endometrial cell colonization shares similarities with cancer, and a dysfunctional immune microenvironment, characterized by non-classically polarized macrophages, plays a critical role in the progression of endometriosis. In this study, a targeted nano delivery system (BSA@Mif NPs) was developed using bovine serum albumin (BSA) as the carrier of mifepristone. The BSA@Mif NPs were utilized to selectively target M2 macrophages highly enriched in ectopic endometrial tissue via the SPARC receptor. This targeting strategy increases drug concentration at ectopic lesions while minimizing its distribution to normal tissue, thereby reducing side effects. In vitro studies demonstrated that BSA@Mif NPs not only enhanced the cellular uptake of M2-type macrophages and ectopic endometrial cells but also improved the cytotoxic effect of mifepristone on ectopic endometrial cells. Furthermore, the BSA@Mif NPs effectively induced immunogenic cell death (ICD) in ectopic endometrial cells and repolarized M2-type macrophages toward the M1 phenotype, resulting in a synergistic inhibition of ectopic endometrial cell growth. In vivo experiments revealed that BSA@Mif NPs exhibited significant therapeutic efficacy in endometriosis-bearing mice by increasing drug accumulation in the endometriotic tissues and modulating the immune microenvironment. This targeted biomimetic delivery strategy presents a promising approach for the development of endometriosis-specific therapies based on existing drugs. STATEMENT OF SIGNIFICANCE: Macrophages play an essential role in immune dysfunctional microenvironment promoting the occurrence and progression of endometriosis and can be a crucial target for developing immune microenvironment regulation strategies for the unmet long-term management of endometriosis. The albumin nanoparticles constructed based on SPARC overexpression in macrophages and endometrial cells and albumin biosafety can achieve the targeted therapy of endometriosis by increasing the passive- and active-mediated drug accumulation in ectopic endometrium and remodeling the immune microenvironment based on macrophage regulation. This study has the following implications: i) overcoming the inherent shortcomings of clinical drugs by nanotechnology is an alternative way of developing medication; ii) developing microenvironment modulation strategies based on macrophage regulation for endometriosis management is feasible.

Effects of Ulipristal Acetate on Reactive Oxygen Species and Proinflammatory Cytokine Release by Epithelial and Stromal Cells from Human Endometrium and Endometriosis

Endometriosis is a condition characterized by increased oxidative stress and chronic inflammation, which can be treated with progestins and other progesterone receptor ligands. However, some patients are refractory to this treatment and the reason is uncertain. Here we investigated the effects of the selective progesterone receptor modulator ulipristal acetate (UPA) on proliferation, reactive oxygen species (ROS), and proinflammatory cytokine production by endometriotic cells and endometrial cells from women with histologically proven endometriosis (n = 22) and endometriosis-free controls (n = 6). Epithelial and stromal cells were isolated and treated in triplicate for 24 h with 1 μM, 10 μM, or 100 μM UPA. Cells were tested for proliferation and ROS production, while cell supernatants were assayed for interleukin (IL)-6, C-C motif chemokine ligand 2 (CCL2), and tumor necrosis factor (TNF)-α concentrations. Proliferation, ROS production, and IL-6 and CCL2 secretion were increased in non-stimulated epithelial and stromal cells from endometriotic lesions compared to endometrial cells from endometriosis patients and controls. UPA induced a dose-dependent increase of cell proliferation only in endometriosis, while enhancing ROS production by all cell types evaluated. UPA reduced CCL2 production in controls but failed to do that in endometriosis, whereas TNF-α was undetectable. We conclude that treatment of endometriotic cells with UPA stimulated in vitro proliferation and ROS production and failed to revert the proinflammatory cytokine excess that characterized these cells, unravelling possible mechanisms of drug resistance in the treatment of endometriosis.

Transcriptome aberration in mice uterus associated with steroid hormone response and inflammation induced by dioxybenzone and its metabolites

Benzophenone-type UV filters have been implicated in multiple adverse reproductive outcomes, yet the underlying processes and molecular targets on the female reproductive tract remain largely unknown. Herein, we investigated the effect of dioxybenzone, one of the widely used congeners, and its demethylated (M1) and hydroxylated (M2) metabolites on transcriptome profiles of ICR mice uterus and identified potential cellular targets in human endometrial stromal cells (HESCs) separated from normal endometrium tissues. Dioxybenzone, M1 and M2 (20 mg/kg bw/d) significantly induced transcriptome aberration with the induction of 683, 802, and 878 differentially expressed genes mainly involved in cancer, reproductive system disease and inflammatory disease. Compared to dioxybenzone, M1 and M2 exhibited a transcriptome profile more similar to estradiol in mice uterus, and subsequently promoted thicker endometrial columnar epithelial layer through upregulation of estrogen receptor target genes-Sprr2s. Dioxybenzone, M1 and M2 (0.1 or 1 μM) also exhibited estrogenic disrupting effect via increasing the mRNA expressions and production of the growth factors responsible for epithelial proliferation, including Fgfs and Igf-1 in HESCs. Additionally, the mRNA expressions of several inflammatory cytokines especially IL-1β in mice uterus and HESCs was significantly upregulated by dioxybenzone and its metabolites. Overall, we revealed that dioxybenzone and its metabolites triggered transcriptome perturbation dually associated with abnormal steroid hormone response and inflammation, both as key determinants to reproductive health risks.

Maternal high-fat diet during pregnancy with concurrent phthalate exposure leads to abnormal placentation

Di(2-ethylhexyl) phthalate (DEHP) is a synthetic chemical commonly used for its plasticizing capabilities. Because of the extensive production and use of DEHP, humans are exposed to this chemical daily. Diet is a significant exposure pathway and fatty food contain the highest level of phthalates. The impact on pregnancy following DEHP exposure and the associated interaction of high fat (HF) diet remains unknown. Here we report that exposure of pregnant mice to an environmentally relevant level of DEHP did not affect pregnancy. In contrast, mice fed a HF diet during gestation and exposed to the same level of DEHP display marked impairment in placental development, resulting in poor pregnancy outcomes. Our study further reveals that DEHP exposure combined with a HF diet interfere with the signaling pathway controlled by nuclear receptor PPARγ to adversely affect differentiation of trophoblast cells, leading to compromised vascularization and glucose transport in the placenta. Collectively, these findings demonstrate that maternal diet during pregnancy is a critical factor that determines whether exposure to an environmental toxicant results in impaired placental and fetal development, causing intrauterine growth restriction, fetal morbidity, and mortality.

Pharmacodynamics and pharmacokinetics of a copper intrauterine contraceptive system releasing ulipristal acetate: A randomized proof-of-concept study

OBJECTIVES

To assess pharmacodynamic and pharmacokinetic outcomes of a novel copper (Cu) intrauterine system (IUS) releasing ulipristal acetate (UPA) in healthy women.

STUDY DESIGN

In this single-blinded, randomized proof-of-concept study, ovulatory women received one of three Cu-IUSs releasing low-dose UPA (5, 20 or 40 µg/d) for 12 weeks. The study included a baseline cycle, three 4-week treatment-cycles and 2 recovery cycles. Primary outcomes included effects of the IUS on bleeding profile, ovarian function, and the occurrence of progesterone receptor modulator associated endometrial changes (PAEC). Pharmacokinetics and safety profile were secondary outcomes. We compared outcomes in treatment-cycle 3 with baseline, using generalized linear mixed models with orthogonal contrasts.

RESULTS

We randomized 29 women (5 µg/d = 10, 20 µg/d = 10, 40 µg/d = 9). All had a successful IUS insertion; 27 completed the 12-week treatment period. Compared to baseline, the mean number of bleeding-only days at treatment-cycle 3 declined by 16.7% in the 5 µg/d group (3.6 vs 3.0, p = 0.66), 40.5% in the 20 µg/d group (4.2 vs 2.5, p = 0.14), and 77% in the 40 µg/d group (3.9 vs 0.9, p = 0.002). Most women reported reduction in the amount of bleeding: 4/8, 8/10, and 7/9 for the 5 µg/d, 20 µg/d, and 40 µg/d groups, respectively. During IUS use, ovulation occurred in most cycles [5 µg/d: 23/24 (96%), 20 µg/d: 26/30 (87%), 40 µg/d: 22/27 (81%)]. The frequency of PAEC at IUS removal was 1/10 (10%), 1/10 (10%) and 4/9 (44%) in the 5 µg/d, 20 µg/d, and 4 0 µg/d groups, respectively. No serious adverse events occurred.

CONCLUSIONS

Reduction in bleeding, low incidence of PAEC, and no serious adverse events are reassuring findings of the novel Cu-UPA-IUS. The 20 µg/d seems the lowest dose promoting a favorable bleeding profile and limiting PAEC.

IMPLICATIONS

The preliminary results of this short-term study of a novel copper intrauterine system (IUS) delivering ulipristal acetate showed reduction of bleeding, low incidence of progesterone receptor modulator associated endometrial changes, and absence of serious adverse events. By preventing copper-induced increase in bleeding, this IUS could provide a noncontraceptive benefit, especially for women with low hemoglobin.

Mifepristone regulates Tregs function mediated by dendritic cells through suppressing the expression of TGF-β

BACKGROUND

Previous studies have demonstrated that mifepristone in the daily low-dose affects the function of endometrium. These researches also implied an alteration of endometrium immune balance, which might be involved in regulating endometrial function. However, the detailed mechanisms remain to be further explored.

METHODS

In this study, the expressions of CD80, CD86, and ICAM-1 in dendritic cells (DCs), which were stimulated with different concentrations of mifepristone (20, 65, and 200 nM), were detected by FACS. After that, we further evaluated the expression of Forkhead box P3 (FOXP3) and IL-10 in Tregs, which co-cultured with mifepristone treated DCs. In mechanism, we compared the indoleamine 2,3-dioxygenase (IDO) and TGF-β expression with enzyme-linked immunosorbent assay (ELISA).

RESULTS

The results indicated that mifepristone promoted the expressions of CD80, CD86, and ICAM-1 in a dosage dependent manner. Reversely, FOXP3 and IL-10 expression levels in Tregs co-cultured with mifepristone-treated DCs were significantly decreased compared with those co-cultured with nontreated DC. Furthermore, a significant reduce in IDO and TGF-β expression was observed in DCs treated with mifepristone. By using the IDO inhibitor (1-methyl tryptophan, 1-MT) or TGF-b supplement, we confirmed that TGF-β, but not IDO could rescue the downregulation of FOXP3 and IL-10 in Tregs co-cultured with mifepristone treated DCs. All of these results suggest that mifepristone may regulate DC function by decreasing TGF-β expression, which further results in the downregulations of FOXP3 and IL-10 in Tregs.

CONCLUSION

Therefore, our research provides a theoretical basis for a potentially clinical application of mifepristone as a novel contraceptive.

Histomorphometric analysis of goat uterine tissue on in vitro exposure with ovarian hormones and mifepristone

Uterus, the largest reproductive tract organ in female mammals, is the site of implantation of fertilised egg and foetus development. Uterus is a dynamic reproductive organ; its morphology alters with reproductive phase and steroidal cues. The aim of the present study was to assess the effects of progesterone (P4), estrogen (E2) and antiprogestogen i.e., mifepristone on goat’s uterine histoarchitecture in in vitro short term culture. Uterine tissue slices were cultured in the presence of E2, P4 and mifepristone at the dose of 10–9 M, 10–7 M and 10–6 M respectively for 24 hours. Uter-ine morphology of E2- and P4-treated groups did not reveal marked changes from that of control group. Mifepristone treatment caused conspicuous changes in uterine histoarchitecture, led to congested endometrium, regressed uterine glands and constricted blood vessels. The changes ob-served in morphometry after E2 and P4 exposure included increased uterine gland diameter (47.00 and 45.95 µm respectively) and glandular epithelial cell height (18.37 and 17.43 µm respectively) while the mifepristone treatment resulted in significant reduction of gland diameter (34.95 µm) as well as epithelium height (14.25 µm) as compared to those in control group (39.9 and 15.56 µm respectively). These morphometrical changes revealed prominent regressive changes in anti-progestin treated group while E2 and P4 showed prolific effects in in vitro culture. Thus it is envis-aged that E2 and P4 induced characteristic progressive changes in the histologic structure especially in endometrial glands of the goat uterus while anti-steroidogenic formulation i.e. mifepristone severely reduced the normal histoarchitecture of the uterus which is a prerequisite for implanta-tion.

Menstruation: science and society

Women's health concerns are generally underrepresented in basic and translational research, but reproductive health in particular has been hampered by a lack of understanding of basic uterine and menstrual physiology. Menstrual health is an integral part of overall health because between menarche and menopause, most women menstruate. Yet for tens of millions of women around the world, menstruation regularly and often catastrophically disrupts their physical, mental, and social well-being. Enhancing our understanding of the underlying phenomena involved in menstruation, abnormal uterine bleeding, and other menstruation-related disorders will move us closer to the goal of personalized care. Furthermore, a deeper mechanistic understanding of menstruation-a fast, scarless healing process in healthy individuals-will likely yield insights into a myriad of other diseases involving regulation of vascular function locally and systemically. We also recognize that many women now delay pregnancy and that there is an increasing desire for fertility and uterine preservation. In September 2018, the Gynecologic Health and Disease Branch of the Eunice Kennedy Shriver National Institute of Child Health and Human Development convened a 2-day meeting, "Menstruation: Science and Society" with an aim to "identify gaps and opportunities in menstruation science and to raise awareness of the need for more research in this field." Experts in fields ranging from the evolutionary role of menstruation to basic endometrial biology (including omic analysis of the endometrium, stem cells and tissue engineering of the endometrium, endometrial microbiome, and abnormal uterine bleeding and fibroids) and translational medicine (imaging and sampling modalities, patient-focused analysis of menstrual disorders including abnormal uterine bleeding, smart technologies or applications and mobile health platforms) to societal challenges in health literacy and dissemination frameworks across different economic and cultural landscapes shared current state-of-the-art and future vision, incorporating the patient voice at the launch of the meeting. Here, we provide an enhanced meeting report with extensive up-to-date (as of submission) context, capturing the spectrum from how the basic processes of menstruation commence in response to progesterone withdrawal, through the role of tissue-resident and circulating stem and progenitor cells in monthly regeneration-and current gaps in knowledge on how dysregulation leads to abnormal uterine bleeding and other menstruation-related disorders such as adenomyosis, endometriosis, and fibroids-to the clinical challenges in diagnostics, treatment, and patient and societal education. We conclude with an overview of how the global agenda concerning menstruation, and specifically menstrual health and hygiene, are gaining momentum, ranging from increasing investment in addressing menstruation-related barriers facing girls in schools in low- to middle-income countries to the more recent "menstrual equity" and "period poverty" movements spreading across high-income countries.

Selective Progesterone Receptor Modulators-Mechanisms and Therapeutic Utility

Selective progesterone receptor modulators (SPRMs) are a new class of compounds developed to target the progesterone receptor (PR) with a mix of agonist and antagonist properties. These compounds have been introduced for the treatment of several gynecological conditions based on the critical role of progesterone in reproduction and reproductive tissues. In patients with uterine fibroids, mifepristone and ulipristal acetate have consistently demonstrated efficacy, and vilaprisan is currently under investigation, while studies of asoprisnil and telapristone were halted for safety concerns. Mifepristone demonstrated utility for the management of endometriosis, while data are limited regarding the efficacy of asoprisnil, ulipristal acetate, telapristone, and vilaprisan for this condition. Currently, none of the SPRMs have shown therapeutic success in treating endometrial cancer. Multiple SPRMs have been assessed for efficacy in treating PR-positive recurrent breast cancer, with in vivo studies suggesting a benefit of mifepristone, and multiple in vitro models suggesting the efficacy of ulipristal acetate and telapristone. Mifepristone, ulipristal acetate, vilaprisan, and asoprisnil effectively treated heavy menstrual bleeding (HBM) in patients with uterine fibroids, but limited data exist regarding the efficacy of SPRMs for HMB outside this context. A notable class effect of SPRMs are benign, PR modulator-associated endometrial changes (PAECs) due to the actions of the compounds on the endometrium. Both mifepristone and ulipristal acetate are effective for emergency contraception, and mifepristone was approved by the US Food and Drug Administration (FDA) in 2012 for the treatment of Cushing's syndrome due to its additional antiglucocorticoid effect. Based on current evidence, SPRMs show considerable promise for treatment of several gynecologic conditions.

Effects of the levonorgestrel intrauterine system on the endometrium after long-term exposure to mifepristone: Secondary outcomes of a randomized controlled trial

OBJECTIVE

Long-term treatment with progesterone receptor modulators (PRM) is associated with a distinct histological entity termed progesterone receptor modulator associated endometrial changes (PAEC). While accumulating evidence implies that these changes are benign and reversible after cessation of treatment, there are currently no data underpinning their development. Consequently, as a precaution, endometrial shedding is recommended after long-term PRM intake. Avoiding endometrial shedding after treatment with a PRM and prior to the start of a progestin treatment would be beneficial for women in reproductive age to avoid pregnancy and bleeding. However, the endometrial morphology with such a treatment regimen is unknown. The aim of this study was to delineate the endometrial morphology following continuous long-term treatment with the PRM mifepristone and subsequent placement of a levonorgestrel intrauterine system (LNG-IUS) without prior shedding of the endometrium.

STUDY DESIGN

This study reports the secondary outcome from a double-blinded randomized controlled trial conducted at Karolinska University Hospital, Sweden, November 2009 to January 2015. Healthy women aged 18-43 years with regular menstrual cycles were included. Eligible women were randomized to receive either 50 mg of mifepristone (n = 29) or a comparator (n = 29), every other day for two months followed by insertion of an LNG-IUS 52 mg. Endometrial biopsies were obtained at baseline and three months after placement of the device. The samples were histologically assessed. The main outcome measure of this sub-study was the endometrial morphology including presence of PAEC three months after LNG-IUS insertion.

RESULTS

Nine and eight paired biopsies from the mifepristone and comparator group, respectively, were included in the histological analysis. There were no differences in baseline characteristics between the groups and all baseline endometrial biopsies were physiological. Three months after LNG-IUS placement the endometrial morphology was still benign without PAEC in all samples treated with either mifepristone or comparator. A progestin effect on the endometrium was seen in all samples.

CONCLUSIONS

Placement of an LNG-IUS immediately following two months' treatment with the PRM mifepristone, without any prior shedding of the endometrium, may represent a feasible approach in terms of endometrial safety. However, larger studies are needed to confirm our results.

Progesterone receptor ligands for the treatment of endometriosis: the mechanisms behind therapeutic success and failure

BACKGROUND

Despite intense research, it remains intriguing why hormonal therapies in general and progestins in particular sometimes fail in endometriosis.

OBJECTIVE AND RATIONALE

We review here the action mechanisms of progesterone receptor ligands in endometriosis, identify critical differences between the effects of progestins on normal endometrium and endometriosis and envisage pathways to escape drug resistance and improve the therapeutic response of endometriotic lesions to such treatments.

SEARCH METHODS

We performed a systematic Pubmed search covering articles published since 1958 about the use of progestins, estro-progestins and selective progesterone receptor modulators, to treat endometriosis and its related symptoms. Two reviewers screened the titles and abstracts to select articles for full-text assessment.

OUTCOMES

Progesterone receptor signalling leads to down-regulation of estrogen receptors and restrains local estradiol production through interference with aromatase and 17 beta-hydroxysteroid dehydrogenase type 1. Progestins inhibit cell proliferation, inflammation, neovascularisation and neurogenesis in endometriosis. However, progesterone receptor expression is reduced and disrupted in endometriotic lesions, with predominance of the less active isoform (PRA) over the full-length, active isoform (PRB), due to epigenetic abnormalities affecting the PGR gene transcription. Oxidative stress is another mechanism involved in progesterone resistance in endometriosis. Among the molecular targets of progesterone in the normal endometrium that resist progestin action in endometriotic cells are the nuclear transcription factor FOXO1, matrix metalloproteinases, the transmembrane gap junction protein connexin 43 and paracrine regulators of estradiol metabolism. Compared to other phenotypes, deep endometriosis appears to be more resistant to size regression upon medical treatments. Individual genetic characteristics can affect the bioavailability and pharmacodynamics of hormonal drugs used to treat endometriosis and, hence, explain part of the variability in the therapeutic response.

WIDER IMPLICATIONS

Medical treatment of endometriosis needs urgent innovation, which should start by deeper understanding of the disease core features and diverse phenotypes and idiosyncrasies, while moving from pure hormonal treatments to drug combinations or novel molecules capable of restoring the various homeostatic mechanisms disrupted by endometriotic lesions.

Nonsurgical Prevention Strategies in BRCA1 and BRCA2 Mutation Carriers

Background

Female carriers of a BRCA1 or 2 germline mutation face a high lifetime risk to develop breast and ovarian cancer. Risk-reducing surgery, such as prophylactic bilateral mastectomy and prophylactic bilateral salpingo-oophorectomy, are proven strategies to prevent breast and ovarian cancer. These procedures are, however, associated with considerable side effects, and the uptake of these highly effective interventions is therefore low in many countries. This highlights the need for alternative and noninvasive strategies for risk reduction in mutation carriers.

Summary

While endocrine treatments with tamoxifen and aromatase inhibitors (AI) have been shown to be effective in secondary prevention, their benefit in primary prevention has never been prospectively evaluated. Moreover, their side effect profile makes them inappropriate candidates for chemoprevention in healthy premenopausal women. Recently, denosumab, a well-tolerated osteoprotective drug, has been shown to have an antitumoral effect on RANK+, BRCA1-deficient luminal progenitor cells in vitro, and has been demonstrated to abrogate tumors in BRCA1-deficient mouse models.

Key Message

The prospectively randomized, double-blind BRCA-P trial is currently investigating the preventative effect of denosumab in healthy BRCA1 germline mutation carriers.

Sonographic and hysteroscopic endometrial examination in women treated with ulipristal acetate: Exploratory findings at a tertiary referral center

OBJECTIVE

Ulipristal acetate (UPA) is a progesterone receptor modulator (PRM) agent that has shown benefits in women with symptomatic uterine fibroids. However, its effects on the endometrium are complex and not fully understood. We describe exploratory findings on macroscopic observation of the endometrium at transvaginal sonography (TVS) and hysteroscopy. The aim of the study is to characterize endometrial patterns commonly observed after UPA treatment.

STUDY DESIGN

We performed a prospective longitudinal study at a tertiary referral center with 100 women with symptomatic uterine fibroids who received a 12-week treatment with UPA (5 mg/day). Patients underwent TVS before and after the treatment, and also a hysteroscopy examination was performed. Main outcome was to compare sonographic and hysteroscopic findings to histology after UPA treatment.

RESULTS

Twenty one out of 100 (21%) women showed PAEC confirmed by histology after UPA treatment. Ultrasound findings were normal in most women after UPA treatment, but 18/100 (18%) showed an endometrial pattern suggestive of PRM effects (non-uniform, homogeneous endometrium with regular cystic areas). Endometrial thickness ≥16 mm was detected in 6/100 patients (6%), and all of them also presented sonographic PRM pattern. No patient presented malignancy according to histology in this subgroup, and 100% of them had PAEC pattern at histology. Among total patient population showing PAEC at histology, only 33% of these were identified by hysteroscopy, while 57% were identified by TVS with the PRM suggestive pattern. Of note, visibility of endometrium was improved at TVS after UPA.

CONCLUSION

Identification of increased endometrial thickness together with the categorized endometrial PRM pattern at TVS may be correlated to benign lesions and may not be a cause of concern. This study is exploratory and further research is necessary to support these conclusions. Nevertheless, TVS seems to be feasible to plan adequate follow-up protocols by avoiding unnecessary interventional procedures such as hysteroscopy.

Molecular characterization of PRM-associated endometrial changes, PAEC, following mifepristone treatment

OBJECTIVE

The progesterone receptor modulator (PRM) mifepristone holds the potential to be developed for regular contraception. However, long-term treatment can cause thickening of the endometrium and PRM-associated endometrial changes (PAEC). The objective of this study was to explore the molecular expression of endometrium displaying PAEC after mifepristone treatment in order to understand the future implications of PAEC and safety of long-term use.

STUDY DESIGN

Endometrial biopsies were obtained from premenopausal women following 3 months of continuous mifepristone treatment. The biopsies were evaluated regarding occurrence of PAEC and followed up by a comparative analysis of gene expression in PAEC endometrium (n=7) with endometrium not displaying PAEC (n=4). Methods used included microarray analysis, Ingenuity Pathway Analysis (IPA) and real-time polymerase chain reaction.

RESULTS

Three genes relevant within endometrial function were up-regulated with PAEC: THY1 (p=.02), ADAM12 (p=.04) and TN-C (p=.04). The proliferation marker MKi67 was not altered (p=.31). None of the differentially regulated genes were involved in the endometrial cancer-signaling pathway (based on IPA knowledge database).

CONCLUSION

The genes altered in endometrium displaying PAEC after 3 months of mifepristone exposure are mainly involved in the structural architecture of tissue.

IMPLICATIONS

PAEC features may be explained by the altered genes and their networks affecting tissue architecture although not involved in endometrial cancer signaling pathways, and thus, treatment with mifepristone at this dosage does not show any adverse effect at endometrial level.