Long-term outcomes of patients with embolic stroke of undetermined source according to subtype

The prognosis of patients with embolic stroke of undetermined source (ESUS) may vary according to the underlying cause. Therefore, we aimed to divide ESUS into subtypes and assess the long-term outcomes. Consecutive patients with acute ischemic stroke who underwent a comprehensive workup, including transesophageal echocardiography and prolonged electrocardiography monitoring, were enrolled. We classified ESUS into minor cardioembolic (CE) ESUS, arteriogenic ESUS, two or more causes ESUS, and no cause ESUS. Arteriogenic ESUS was sub-classified into complex aortic plaque (CAP) ESUS and non-stenotic (< 50%) relevant artery plaque (NAP) ESUS. A total of 775 patients were enrolled. During 1286 ± 748 days follow-up, 116 major adverse cardiovascular events (MACE) occurred (4.2 events/100 patient-years). Among the ESUS subtypes, CAP ESUS was associated with the highest MACE frequency (9.7/100 patient-years, p = 0.021). Cox regression analyses showed that CAP ESUS was associated with MACE (hazard ratio 2.466, 95% confidence interval 1.305-4.660) and any stroke recurrence (hazard ratio 2.470, 95% confidence interval, 1.108-5.508). The prognosis of ESUS varies according to the subtype, with CAP ESUS having the worst prognosis. Categorizing ESUS into subtypes could improve patient care and refine clinical trials.

ERBB2 Targeting Reveals a Significant Suppression of Tumorigenesis in Murine Endometrial Cancer with Pten Mutation

Endometrial cancer is the most common gynecologic malignancy. PTEN is a negative regulator of PI3K signaling and is deficient in > 50% of primary human endometrial cancer. Amplification of ERBB2 promotes tumorigenesis and pathogenesis of several human cancers. However, the effect of ERBB2 targeting has not been studied in endometrial cancer with PTEN mutations. The murine model Pgrcre/+Erbb2f/fPtenf/f (Erbb2d/d Ptend/d) was developed to evaluate the effect of ERBB2 targeted therapy in endometrial cancer with PTEN deficiency. Histopathological and molecular analysis was performed for Ptend/d and Erbb2d/dPtend/d mice. Histopathological analysis revealed that Erbb2d/dPtend/d mice significantly reduced development and progression of endometrial cancer compared to Ptend/d mice. Furthermore, percentage of proliferative cells in Erbb2d/dPtend/d mice revealed anti-tumorigenic effect of Erbb2 ablation compared to Ptend/d mice. Our results demonstrate that Erbb2 ablation reveals a significant suppression of tumorigenesis on endometrial cancer of Ptend/d mice. Our results suggest that Erbb2 functions as an oncogene in endometrial cancer of Ptend/d mice implying that Erbb2 targeting can be used as an effective therapeutic approach for treatment of endometrial cancer with PTEN deficiency to hinder cancer development.

ARG1 Is a Potential Prognostic Marker in Metastatic Endometrial Cancer

Endometrial cancer (EC) is the most common gynecologic malignancy. While the majority of patients present with early-stage and low-grade EC and have an excellent prognosis, a subset has metastatic disease at presentation or develops distant recurrence after initial treatment of the primary. However, the lack of prognostic biomarkers for metastatic EC is a critical barrier. Arginase 1 (ARG1) regulates the last step of the urea cycle, and an increase in ARG1 has been correlated as a poor prognostic factor in a variety of cancers. In the present study, ARG1 expression was evaluated as a potential prognostic marker for metastatic EC in endometrial hyperplasia and cancer of mice with Pten mutation as well as Pten and Mig-6 double mutations. While Pten mutation in the uterus is not sufficient for distant metastasis, mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. Our immunostaining and RT-qPCR analysis revealed that the expression of ARG1 in early stage of EC as well as endometrial hyperplasia from mice deficient in Mig-6 and Pten mutations significantly increased compared to Pten mutation in the uterus. The results suggest that a high level of ARG1 is associated with poor prognosis in association with EC of mouse.

Transcriptomic changes in eutopic endometrium and ectopic lesions during endometriosis progression in a mouse model

OBJECTIVE

To identify the transcriptomic changes of ectopic lesions and eutopic endometrial tissues during the progression of endometriosis, we performed transcriptomic analysis in the eutopic endometrium and ectopic lesions.

DESIGN

Laboratory study.

SETTING

Academic medical center.

ANIMALS

Four fertile and 4 subfertile Pgrcre/+Rosa26mTmG/+ mice with endometriosis, and 4 sham mice for each group of endometriosis mice as control. These mice underwent either surgery to induce endometriosis or sham surgery. Fertile sham and mice with endometriosis were used 1 month after surgery, whereas subfertile ones were used 3 months after surgery.

INTERVENTIONS

Early and chronic effects of endometriosis on transcriptomics of ectopic lesions and eutopic endometrium.

MAIN OUTCOME MEASURES

RNA-sequencing analysis and identification of differentially expressed genes and pathways in the ectopic lesions and eutopic uteri from mice with endometriosis and sham mice at day 3.5 of pregnancy.

RESULTS

Our mouse model recapitulates the transcriptomic changes of ectopic lesions in humans. RNA-sequencing analysis was performed in ectopic lesions and eutopic uteri from mice with or without endometriosis during the progression of the disease. Estrogen activity, inflammation, angiogenesis, and fibrosis pathways were consistently elevated in all the ectopic lesions compared with eutopic endometrium. Cholesterol/glucose synthesis and stem cell pluripotency pathways were more enhanced in ectopic lesions from subfertile mice compared with their eutopic endometrium. Dysregulation of infiltration of macrophage, dendritic, T and B cells was validated with the use of immunohistochemistry in ectopic lesions. Multiple ligand-receptor pairs between the ectopic and eutopic endometrium were altered compared with the sham endometrium. Suppressed WNT and EGF pathways were only found in the eutopic endometrium from subfertile not fertile mice compared with sham.

CONCLUSIONS

Our mouse endometriosis model recapitulates the transcriptomics of ectopic lesions in humans. Our transcriptomic analysis during endometriosis progression in our mouse model will help us understand the pathophysiology of endometriosis.

Epigenetic Dysregulation in Endometriosis: Implications for Pathophysiology and Therapeutics

Endometriosis is a prevalent gynecological condition associated with pelvic pain and infertility. Despite more than a century of research, the etiology of endometriosis still eludes scientific consensus. This lack of clarity has resulted in suboptimal prevention, diagnosis, and treatment options. Evidence of genetic contributors to endometriosis is interesting but limited; however, significant progress has been made in recent years in identifying an epigenetic role in the pathogenesis of endometriosis through clinical studies, in vitro cell culture experiments, and in vivo animal models. The predominant findings include endometriosis-related differential expression of DNA methyltransferases and demethylases, histone deacetylases, methyltransferases, and demethylases, and regulators of chromatin architecture. There is also an emerging role for miRNAs in controlling epigenetic regulators in the endometrium and endometriosis. Changes in these epigenetic regulators result in differential chromatin organization and DNA methylation, with consequences for gene expression independent of a genetic sequence. Epigenetically altered expression of genes related to steroid hormone production and signaling, immune regulation, and endometrial cell identity and function have all been identified and appear to play into the pathophysiological mechanisms of endometriosis and resulting infertility. This review summarizes and critically discusses early seminal findings, the ever-growing recent evidence of epigenetic contributions to the pathophysiology of endometriosis, and implications for proposed epigenetically targeted therapeutics.

ARG1 is a potential prognostic marker in metastatic and recurrent endometrial cancer

Endometrial cancer (EC) is the most common gynecologic malignancy. While the majority of patients present with early-stage and low-grade EC and have an excellent prognosis, a subset has metastatic disease at presentation, or develops distant recurrence after initial treatment of the primary. However, the lack of prognostic biomarkers for metastatic EC is a critical barrier. Arginase 1 (ARG1) regulates the last step of the urea cycle, and an increase in ARG1 has been correlated as a poor prognostic factor in a variety of cancers. In the present study, ARG1 expression was evaluated as a potential prognostic marker for metastatic EC in endometrial hyperplasia and cancer of mice with Pten mutation as well as Pten and Mig-6 double mutations. While Pten mutation in the uterus is not sufficient for distant metastasis, mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. Our immunostaining and RT-qPCR analysis revealed that the expression of ARG1 in early stage of EC as well as endometrial hyperplasia from mice deficient in Mig-6 and Pten mutations significantly increased compared to Pten mutation in the uterus. The results suggest that a high level of ARG1 is associated with poor prognosis in association with EC of mouse.

Pancreatic loss of Mig6 alters murine endocrine cell fate and protects functional beta cell mass in an STZ-induced model of diabetes

Background

Maintaining functional beta cell mass (BCM) to meet glycemic demands is essential to preventing or reversing the progression of diabetes. Yet the mechanisms that establish and regulate endocrine cell fate are incompletely understood. We sought to determine the impact of deletion of mitogen-inducible gene 6 (Mig6), a negative feedback inhibitor of epidermal growth factor receptor (EGFR) signaling, on mouse endocrine cell fate. The extent to which loss of Mig6 might protect against loss of functional BCM in a multiple very low dose (MVLD) STZ-induced model of diabetes was also determined.

Methods

Ten-week-old male mice with whole pancreas (Pdx1:Cre, PKO) and beta cell-specific (Ins1:Cre, BKO) knockout of Mig6 were used alongside control (CON) littermates. Mice were given MVLD STZ (35 mg/kg for five days) to damage beta cells and induce hyperglycemia. In vivo fasting blood glucose and glucose tolerance were used to assess beta cell function. Histological analyses of isolated pancreata were utilized to assess islet morphology and beta cell mass. We also identified histological markers of beta cell replication, dedifferentiation, and death. Isolated islets were used to reveal mRNA and protein markers of beta cell fate and function.

Results

PKO mice had significantly increased alpha cell mass with no detectable changes to beta or delta cells. The increase in alpha cells alone did not impact glucose tolerance, BCM, or beta cell function. Following STZ treatment, PKO mice had 18±8% higher BCM than CON littermates and improved glucose tolerance. Interestingly, beta cell-specific loss of Mig6 was insufficient for protection, and BKO mice had no discernable differences compared to CON mice. The increase in BCM in PKO mice was the result of decreased beta cell loss and increased beta cell replication. Finally, STZ-treated PKO mice had more Ins+/Gcg+ bi-hormonal cells compared to controls suggesting alpha to beta cell transdifferentiation.

Conclusions

Mig6 exerted differential effects on alpha and beta cell fate. Pancreatic loss of Mig6 reduced beta cell loss and promoted beta cell growth following STZ. Thus, suppression of Mig6 may provide relief of diabetes.

Notch effector recombination signal binding protein for immunoglobulin kappa J signaling is required for the initiation of endometrial stromal cell decidualization†

The Notch signaling pathway is required for reproductive success. This pathway activates its transcriptional effector, recombination signal binding protein for immunoglobulin kappa J (Rbpj), to induce transcription of its target genes. This signaling pathway is required for successful decidualization, implantation, and uterine repair following parturition. To identify the compartmental specific roles of the Notch signaling pathway in the establishment of pregnancy, we generated epithelial and decidual stromal cell specific knockouts of Rbpj utilizing lactoferrin iCre and Prl8A2 iCre, respectively. Both conditional knockout mouse models were fertile. The Rbpj epithelial knockout mice displayed 27% resorption sites at E15.5, but this did not significantly impact the number of live born pups compared with controls. In addition, the Rbpj epithelial knockout mice displayed increased estrogen signaling in their stromal compartment. Given that both mouse models exhibited fertility comparable to control animals, the epithelial and stromal specific nature of the iCre recombinases utilized, and previously published Rbpj total uterine knockout mouse models, we conclude that Notch effector Rbpj signaling is required at the initiation of pregnancy to support decidualization in stromal cells, but that Rbpj is not required in the epithelial compartment nor is it required for post-implantation pregnancy success.

Leptin Stimulates Endometriosis Development in Mouse Models

Endometriosis is a chronic inflammatory condition in women, and obesity leads to an inflammatory condition that is directly involved in the etiology of endometriosis. However, observational studies have shown an inverse correlation between endometriosis and a low body mass index (BMI). Obesity does not protect against endometriosis, and on the contrary, an increased BMI may lead to more severe forms of the disease. To determine the effect of obesity on endometriosis, diet-induced and genetically engineered obese mouse models were integrated with endometriosis mouse models with fluorescence-tagged ectopic lesions. High-fat diet-induced obese mice revealed a significant increase in endometriosis development compared with regular-diet control mice. However, obese recipient mice with leptin deficiency and leptin receptor deficiency showed suppressed endometriosis development compared with control mice. Furthermore, donor uterine tissues with leptin deficiency and leptin receptor deficiency suppressed endometriosis development compared with control donor in control recipient mice. Importantly, we revealed that aberrant high levels of leptin concentration significantly increased endometriosis development compared with vehicle treatment group in control mice with normal body weight. Our results suggest that leptin and its receptor are critical for endometriosis development.

SIRT1 plays an important role in implantation and decidualization during mouse early pregnancy

Sirtuin 1 (SIRT1) is a member of the sirtuin family that functions to deacetylate both histones and non-histone proteins. Previous studies have identified significant SIRT1 upregulation in eutopic endometrium from infertile women with endometriosis. However, SIRT1 function in the uterus has not been directly studied. Using immunochemistry analysis, we found SIRT1 to be most strongly expressed at GD4.5 and GD5.5 in decidualized cells and at GD7.5 in secondary decidual cells in mouse. To assess the role of SIRT1 in uterine function, we generated uterine Sirt1 conditional knockout mice (Pgrcre/+Sirt1f/f; Sirt1d/d). A 6-month fertility trial revealed that Sirt1d/d females were subfertile. Implantation site numbers were significantly decreased in Sirt1d/d mice compared with controls at GD5.5. Sirt1d/d implantation sites at GD4.5 could be divided into two groups, Group #1 with luminal closure and nonspecific COX2 expression compared with controls (14/20) and Group #2 with an open lumen and no COX2 (6/20). In Sirt1d/d Group #1, nuclear FOXO1 expression in luminal epithelial cells was significantly decreased. In Sirt1d/d Group #2, nuclear FOXO1 expression was almost completely absent, and there was strong PGR expression in epithelial cells. At GD5.5, stromal PGR and COX2 were significantly decreased in Sirt1d/d uterine in the areas surrounding the embryo compared with controls, indicating defective decidualization. An artificially induced decidualization test revealed that Sirt1d/d females showed defects in decidualization response. All together, these data suggest that SIRT1 is important for decidualization and contributes to preparing a receptive endometrium for successful implantation.

A Mouse Model of Endometriosis with Nanoparticle Labeling for In Vivo Photoacoustic Imaging

Endometriosis is a condition of the female reproductive tract characterized by endometrium-like tissue growing outside the uterus. Though it is a common cause of pelvic pain and infertility, there is currently no reliable noninvasive method to diagnose the presence of endometriosis without surgery, and the pathophysiological mechanisms that lead to the occurrence of symptoms require further inquiry. Due to patient heterogeneity and delayed diagnosis, animal models are commonly used to study the development of endometriosis, but these are costly due to the large number of animals needed to test various treatments and experimental conditions at multiple endpoints. Here, we describe a method for synthesis of multimodal imaging gold-fluorescein isothiocyanate (FITC) nanoparticles with preclinical application via induction of nanoparticle-labeled endometriosis-like lesions in mice. Labeling donor endometrial tissue fragments with gold-FITC nanoparticles prior to induction of endometriosis in recipients enables in vivo detection of the gold-labeled lesions with photoacoustic imaging. The same imaging method can be used to visualize embryos noninvasively in pregnant mice. Furthermore, the conjugated FITC dye on the gold nanoparticles allows easy isolation of labeled lesion tissue under a fluorescence dissection microscope. After dissection, the presence of gold-FITC nanoparticles and endometrium-like histology of lesions can be verified through fluorescence imaging, gold enhancement, and immunostaining. This method for in vivo imaging of endometriosis-like lesions and fluorescence-guided dissection will permit new experimental possibilities for the longitudinal study of endometriosis development and progression as well as endometriosis-related infertility.

Endometrial Epithelial ARID1A Is Required for Uterine Immune Homeostasis during Early Pregnancy

A growing body of work suggests epigenetic dysregulation contributes to endometriosis pathophysiology and female infertility. The chromatin remodeling complex subunit AT-rich interaction domain 1A (ARID1A) must be properly expressed to maintain normal uterine function. Endometrial epithelial ARID1A is indispensable for pregnancy establishment in mice through regulation of endometrial gland function; however, ARID1A expression is decreased in infertile women with endometriosis. We hypothesized that ARID1A performs critical operations in the endometrial epithelium necessary for fertility besides maintaining gland function. To identify alterations in uterine gene expression resulting from loss of epithelial ARID1A, we performed RNA-sequencing analysis on pre-implantation uteri from Ltf^iCre/+Arid1a^f/f and control mice. Differential expression analysis identified 4181 differentially expressed genes enriched for immune-related ingenuity canonical pathways including agranulocyte adhesion and diapedesis and natural killer cell signaling. RT-qPCR confirmed an increase in pro-inflammatory cytokine and macrophage-related gene expression but a decrease in natural killer cell signaling. Immunostaining confirmed a uterus-specific increase in macrophage infiltration. Flow cytometry delineated an increase in inflammatory macrophages and a decrease in uterine dendritic cells in Ltf^iCre/+Arid1a^f/f uteri. These findings demonstrate a role for endometrial epithelial ARID1A in suppressing inflammation and maintaining uterine immune homeostasis, which are required for successful pregnancy and gynecological health.

Nuclear Progesterone Receptor Expressed by the Cortical Thymic Epithelial Cells Dictates Thymus Involution in Murine Pregnancy

Progesterone is a gonadal pro-gestational hormone that is absolutely necessary for the success of pregnancy. Most notable actions of progesterone are observed in the female reproductive organs, the uterus and the ovary. Acting through the nuclear progesterone receptor (PGR), progesterone prepares the endometrium for implantation of the embryo. Interestingly, the maternal thymus also is a known expressor of Pgr; its absence is associated with murine pregnancy complications. However, the localization of its expression and its functional importance were not known. Here, we used a transgenic dual fluorescent reporter mouse model and genetic deletion of Pgr in Foxn1+ thymic epithelial cells (TEC) to demonstrate TEC-specific Pgr expression in pregnancy, especially in the cortex where thymocyte maturation occurs. Using our TEC-specific Pgr deletion mouse model, we demonstrate that TEC-specific Pgr is necessary for pregnancy-induced thymic involution in pregnancy. Our investigation reveals that PGR expression is upregulated in the cortical thymic epithelial cells during pregnancy, and that PGR expression is important for thymic involution during murine pregnancy.

Loss of MIG-6 results in endometrial progesterone resistance via ERBB2

Female subfertility is highly associated with endometriosis. Endometrial progesterone resistance is suggested as a crucial element in the development of endometrial diseases. We report that MIG-6 is downregulated in the endometrium of infertile women with endometriosis and in a non-human primate model of endometriosis. We find ERBB2 overexpression in the endometrium of uterine-specific Mig-6 knockout mice (Pgr^cre/+Mig-6^f/f; Mig-6^d/d). To investigate the effect of ERBB2 targeting on endometrial progesterone resistance, fertility, and endometriosis, we introduce Erbb2 ablation in Mig-6^d/d mice (Mig-6^d/dErbb2^d/d mice). The additional knockout of Erbb2 rescues all phenotypes seen in Mig-6^d/d mice. Transcriptomic analysis shows that genes differentially expressed in Mig-6^d/d mice revert to their normal expression in Mig-6^d/dErbb2^d/d mice. Together, our results demonstrate that ERBB2 overexpression in endometrium with MIG-6 deficiency causes endometrial progesterone resistance and a nonreceptive endometrium in endometriosis-related infertility, and ERBB2 targeting reverses these effects.

Female subfertility is highly associated with endometriosis. Here the authors show that progesterone-induced MIG-6 is reduced in endometrium of infertile women and non-human primates with endometriosis, and in a mouse model find that Erbb2 is the key mediator of Mig-6 loss induced endometriosis-related infertility.

Role of SIRT1 and Progesterone Resistance in Normal and Abnormal Endometrium

CONTEXT

Progesterone resistance, a known pathologic condition associated with a reduced cellular response to progesterone and heightened estrogen responses, appears to have a normal physiologic role in mammalian reproduction. The molecular mechanism responsible for progesterone resistance in normal and abnormal endometrium remains unclear.

OBJECTIVE

To examine the roles of sirtuin-1 (SIRT1) in normal endometrium as well as endometrium associated with infertility and endometriosis, as an epigenetic modulator associated with progesterone resistance.

METHODS

SIRT1 expression was examined by Western blot, quantitative real-time polymerase chain reaction, and immunohistochemistry in mouse uterus and human endometrium. Mice with uterine specific Sirt1 overexpression were developed to examine SIRT1's role in endometrial function and endometriosis development. EX-527, a SIRT1 inhibitor, and SRT1720, a SIRT1 agonist, were also used to evaluate SIRT1 effect on endometriosis.

RESULTS

In normal healthy women, endometrial SIRT1 is expressed only during menses. SIRT1 was dramatically overexpressed in the endometrium from women with endometriosis in both the epithelium and stroma. In mice, SIRT1 is expressed at the time of implantation between day 4.5 and 5.5 of pregnancy. Overexpression of SIRT1 in the mouse uterus leads to subfertility due to implantation failure, decidualization defects and progesterone resistance. SIRT1 overexpression in endometriotic lesions promotes worsening endometriosis development. EX-527 significantly reduced the number of endometriotic lesions in the mouse endometriosis model.

CONCLUSIONS

SIRT1 expression and progesterone resistance appears to play roles in normal endometrial functions. Aberrant SIRT1 expression contributes to progesterone resistance and may participate in the pathophysiology of endometriosis. SIRT1 is a novel and targetable protein for the diagnosis as well as treatment of endometriosis and the associated infertility seen in this disease.

Corrigendum: Nuclear Progesterone Receptor Expressed by the Cortical Thymic Epithelial Cells Dictates Thymus Involution in Murine Pregnancy

[This corrects the article DOI: 10.3389/fendo.2022.846226.].

ARID1A and PGR proteins interact in the endometrium and reveal a positive correlation in endometriosis

Endometriosis is a disorder in which endometrial cells normally limited to the lining of the uterus proliferate outside the uterine cavity and can cause pelvic pain and infertility. ARID1A levels are significantly reduced in the eutopic endometrium from women with endometriosis. Uterine specific Arid1a knock-out mice were infertile due to loss of epithelial progesterone receptor (PGR) signaling. However, the functional association of ARID1A and PGR in endometriosis has not been studied. We examined the expression patterns and co-localization of ARID1A and PGR in eutopic endometrium from women with and without endometriosis using immunostaining and Western blot analysis. ARID1A and PGR proteins co-localized in the epithelium during the proliferative and the early secretory phases. Our immunoprecipitation analysis and proximity ligation assay (PLA) revealed physical interaction between ARID1A and PGR-A but not PGR-B in the mouse and human endometrium. ARID1A levels positively correlated with PGR levels in the eutopic endometrium of women with endometriosis. Our results bring new perspectives on the molecular mechanisms involved in endometrial receptivity and progesterone resistance in endometriosis. The interrelationship between ARID1A and PGR may contribute to explaining the non-receptive endometrium in endometriosis-related infertility.

Genetic and epigenetic changes in the eutopic endometrium of women with endometriosis: association with decreased endometrial αvβ3 integrin expression

About 40% of women with infertility and 70% of women with pelvic pain suffer from endometriosis. The pregnancy rate in women undergoing IVF with low endometrial integrin αvβ3 (LEI) expression is significantly lower compared to the women with high endometrial integrin αvβ3 (HEI). Mid-secretory eutopic endometrial biopsies were obtained from healthy controls (C; n=3), and women with HEI (n=4) and LEI (n=4) and endometriosis. Changes in gene expression were assessed using human gene arrays and DNA methylation data were derived using 385 K Two-Array Promoter Arrays. Transcriptional analysis revealed that LEI and C groups clustered separately with 396 differentially expressed genes (DEGs) (P<0.01: 275 up and 121 down) demonstrating that transcriptional and epigenetic changes are distinct in the LEI eutopic endometrium compared to the C and HEI group. In contrast, HEI vs C and HEI vs LEI comparisons only identified 83 and 45 DEGs, respectively. The methylation promoter array identified 1304 differentially methylated regions in the LEI vs C comparison. The overlap of gene and methylation array data identified 14 epigenetically dysregulated genes and quantitative RT-PCR analysis validated the transcriptomic findings. The analysis also revealed that aryl hydrocarbon receptor (AHR) was hypomethylated and significantly overexpressed in LEI samples compared to C. Further analysis validated that AHR transcript and protein expression are significantly (P<0.05) increased in LEI women compared to C. The increase in AHR, together with the altered methylation status of the 14 additional genes, may provide a diagnostic tool to identify the subset of women who have endometriosis-associated infertility.

Abstract PO041: Everolimus and MK-2206 reverse P4-resistant endometrial hyperplasia in Mig-6 mutant mice

Endometrial cancer is the most frequent type of gynecological tumor in the United States. Hysterectomy, the surgical removal of the uterus, is the main therapy for endometrial cancer, but this is not an option for women seeking to preserve their fertility. In cases of early-stage endometrial cancer and endometrial hyperplasia, hormonal therapy is a vital nonsurgical option. However, progesterone (P4) resistance robs women of the option to choose hormone therapy to preserve their uterus. Therefore, developing nonsurgical treatments for endometrial cancer remains an essential goal for women who wish to maintain endometrial functions and women in high-risk surgical conditions. Mitogen-inducible gene 6 (MIG-6) acts as a tumor suppressor during endometrial tumorigenesis and as a P4 target gene in humans and mice. We developed mice with the conditional knockout of Mig-6 in all uterine compartments (Pgrcre/+Mig-6f/f; Mig-6KO) and endometrial epithelial cell-specific Mig-6 knockout (Sprr2fcre/+Mig-6f/f; Mig-6Ep-KO) mice. P4 treatment abated the development of endometrial hyperplasia and restored morphological and histological characteristics of the uterus of Mig-6Ep-KO mice, but Mig-6Ep-KO mice showed P4 resistance. P4 treatment reduced cell proliferation which was accompanied by decreased AKT signaling. In order to investigate the inhibition effect of AKT/mTOR signaling as non-surgical treatment on P4-resistant endometrial hyperplasia, we treated Mig-6KO and Mig-6Ep-KO mice with either: 1) vehicle (PBS); 2) MK-2206 (360 mg/kg, once a week); or 3) everolimus (10mg/kg daily) at 10 weeks old (n=6/treatment/genotype) for 1 month. MK-2206 has completed phase II trials and inhibits AKT phosphorylation. Everolimus is FDA-approved mTOR inhibitor. The vehicle group of Mig-6KO and Mig-6Ep-KO mice manifested the endometrial hyperplasia phenotype. In contrast, IHC analysis showed that the groups receiving MK-2206 or everolimus experienced significantly decreased AKT phosphorylation and phosphorylated S6 levels, respectively, and decreased epithelial proliferation, resulting in restoration of normal uterine histology. These data suggest that everolimus and MK-2206 may be new non-surgical treatment options for P4-resistant endometrial hyperplasia. This information may help guide more effective non-surgical interventions in the future. The project described was supported by Grant Number P50CA098258 from the National Cancer Institute. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute or the National Institutes of Health.

Citation Format: Tae Hoon Kim, Jae-Wook Jeong. Everolimus and MK-2206 reverse P4-resistant endometrial hyperplasia in Mig-6 mutant mice [abstract]. In: Proceedings of the AACR Virtual Special Conference: Endometrial Cancer: New Biology Driving Research and Treatment; 2020 Nov 9-10. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(3_Suppl):Abstract nr PO041.

Endometrial epithelial ARID1A is critical for uterine gland function in early pregnancy establishment

Though endometriosis and infertility are clearly associated, the pathophysiological mechanism remains unclear. Previous work has linked endometrial ARID1A loss to endometriosis-related endometrial non-receptivity. Here, we show in mice that ARID1A binds and regulates transcription of the Foxa2 gene required for endometrial gland function. Uterine-specific deletion of Arid1a compromises gland development and diminishes Foxa2 and Lif expression. Deletion of Arid1a with Ltf-iCre in the adult mouse endometrial epithelium preserves the gland development while still compromising the gland function. Mice lacking endometrial epithelial Arid1a are severely sub-fertile due to defects in implantation, decidualization, and endometrial receptivity from disruption of the LIF-STAT3-EGR1 pathway. FOXA2 is also reduced in the endometrium of women with endometriosis in correlation with diminished ARID1A, and both ARID1A and FOXA2 are reduced in nonhuman primates induced with endometriosis. Our findings describe a role for ARID1A in the endometrial epithelium supporting early pregnancy establishment through the maintenance of gland function.

Animal Models of Adenomyosis

Adenomyosis is a nonmalignant uterine disorder in which endometrial tissue exists within and grows into the myometrium. Animal models have generated limited insight into the still-unclear pathogenesis of adenomyosis, provided a platform for preclinical screening of many drugs and compounds with potential as therapeutics, and elucidated mechanisms underlying the pain and fertility issues that occur in many women with the disease. Spontaneous adenomyosis has been studied in nonhuman primates, primarily in the form of case reports. Adenomyosis is routinely experimentally induced in mice through methods such as neonatal tamoxifen exposure, pituitary engraftment, and human tissue xenotransplantation. Several studies have also reported hormonal or environmental toxicant exposures that give rise to murine adenomyosis, and genetically engineered models have been created that recapitulate the human-like condition, most notably involving alteration of β-catenin expression. This review describes the animal models for adenomyosis and their contributions to our understanding of the factors underpinning the development of symptoms. Animal models represent a unique opportunity for understanding the molecular basis of adenomyosis and developing efficacious treatment options for affected women. Herein, we assess their different potentials and limitations with regard to identification of new therapeutic interventions and reflect on future directions for research and drug validation.

Abstract 428: The role of Mig-6 as a tumor suppressor in metastatic and recurrent endometrial cancer

Endometrial cancer is the most common gynecologic malignancy with an estimated 63,230 new cases in 2018. Although early-stage and low grade endometrioid endometrial cancers (EEC) generally exhibit a favorable prognosis, 10-15% of tumors recur within 5 years with poor treatment outcomes and low survival rates. Therefore, there is an urgent obligation to explore the mechanism of tumor metastasis and recurrence to further elucidate the progression of EEC. Mitogen inducible gene 6 (MIG-6) plays a tumor suppressor role in endometrial cancer. Ablation of Mig-6 in the murine uterus leads to the development of endometrial hyperplasia and E2-induced EEC. However, how MIG-6 suppresses tumorigenesis and metastasis in EEC is unclear. We have developed a genetically engineered mouse model for metastatic and recurrent EEC that implicates coexistent Pten and Mig-6 mutations in EEC. We also added a double-fluorescent Cre reporter to our EEC mouse model to distinguish EEC from surrounding normal tissues. In Pgrcre/+Rosa26mTmG mice, the Pgr-positive uterine cells express GFP, while Pgr-negative cells express membrane-targeted tandem dimer Tomato. The ablation of both Mig-6 and Pten in the uterus (Pgrcre/+Mig-6f/fPtenf/f; Mig-6d/dPtend/d) dramatically accelerated the development of EEC compared to single ablation of either gene. Importantly, Pten mutation is not sufficient for distant metastasis, but mice with concurrent ablation of Mig-6 and Pten develop distant metastasis. After hysterectomy at stage I of EEC, 62% of Mig-6d/dPtend/d mice (5/8) developed recurrence of EEC in the abdomen and lung. Cholesterol metabolism plays a significant role in cancer metastasis, and Mig-6 plays a critical role in the regulation of cholesterol homeostasis and bile acid synthesis. The ingenuity pathway analysis revealed that cholesterol biosynthesis was the most significantly changed pathway in the endometrial hyperplasia from 2-week-old Mig-6d/dPtend/d mice compared with Ptend/d mice. We found 67 and 18 significantly increased or decreased transcripts, respectively, that are related cholesterol biosynthesis. HMG-coA reductase inhibitors, commonly known as statins, account for the great majority of cholesterol-lowering drug use. However, little is known about the association between statin use and incidence of most types of cancers. To determine the effect of statins on tumorigenesis of EEC in Mig-6d/dPtend/d mice, the mutant mice were treated with atorvastatin (10mg/kg/day oral administration) or vehicle for 2 months. Treatment with statins significantly reduced development and progression of EEC in Mig-6d/dPtend/d mice compared to the vehicle group. Our results demonstrate that Mig-6 suppresses metastasis and recurrence in EEC with Pten mutation by inhibiting cholesterol biosynthesis. Research reported in this publication was supported by The Mary Kay Foundation 2019 research grant.

Citation Format: Tae Hoon Kim, Ryan M. Marquardt, Russell R. Broaddus, Jae-Wook Jeong. The role of Mig-6 as a tumor suppressor in metastatic and recurrent endometrial cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 428.

Interleukin-13 receptor subunit alpha-2 is a target of progesterone receptor and steroid receptor coactivator-1 in the mouse uterus†

The endometrium, composed of epithelial and stromal cell compartments, is tightly regulated by the ovarian steroid hormones estrogen (E2) and progesterone (P4) during early pregnancy. Through the progesterone receptor (PGR), steroid receptor coactivators, and other transcriptional coregulators, progesterone inhibits E2-induced cell proliferation and induces the differentiation of stromal cells in a process called decidualization to promote endometrial receptivity. Although interleukin-13 receptor subunit alpha-2 (Il13ra2) is expressed in the human and mouse endometrium, its potential role in the steroid hormone regulation of the endometrium has not been thoroughly examined. In this study, we employed PGR knockout mice and steroid receptor coactivator-1 knockout mice (SRC-1-/-) to profile the expression of Il13ra2 in the murine endometrium and determine the role of these transcriptional regulators in the hormone-responsiveness of Il13ra2 expression. Furthermore, we utilized a well-established decidualization-inducing steroidogenic cocktail and a siRNA-based knockdown of IL13RA2 to determine the importance of IL13RA2 in the decidualization of primary human endometrial stromal cells. Our findings demonstrate that Il13ra2 is expressed in the subepithelial stroma of the murine endometrium in response to ovarian steroid hormones and during early pregnancy in a PGR- and SRC-1-dependent manner. Furthermore, we show that knockdown of IL13RA2 before in vitro decidualization of primary human endometrial stromal cells partially compromises the full decidualization response. We conclude that Il13ra2 is a downstream target of progesterone through PGR and SRC-1 and plays a role in mediating the stromal action of ovarian steroid hormones.

An immune competent orthotopic model of endometrial cancer with metastasis

Endometrial cancer is the most common gynecologic malignancy in the U.S. with metastatic disease remaining the major cause of patient death. Therapeutic strategies have remained essentially unchanged for decades. A significant barrier to progression in treatment modalities stems from a lack of clinically applicable in vivo models to accurately mimic endometrial cancer; specifically, ones that form distant metastases and maintain an intact immune system. To address this problem, we have established the first immune competent murine orthotopic tumor model for metastatic endometrial cancer by creating a green fluorescent protein labeled cell line from an endometrial cancer that developed in a Pgr ^cre/+ Pten ^f/f Kras ^G12D genetically engineered mouse. These cancer cells were grafted into the abraded uterine lumen of ovariectomized recipient mice treated with estrogen and subsequently developed local and metastatic endometrial tumors. We noted primary tumor formation in 59% mixed background and 86% of C57BL/6 animals at 4 weeks and distant lung metastases in 78% of mice after 2 months. This immunocompetent orthotopic tumor model closely resembles some human metastatic endometrial cancer, modeling both local metastasis and hematogenous spread to lung and has significant potential to advance the study of endometrial cancer and its metastasis.

Overexpression of MIG-6 in the cartilage induces an osteoarthritis-like phenotype in mice

Background

Osteoarthritis (OA) is the most common form of arthritis and characterized by degeneration of the articular cartilage. Mitogen-inducible gene 6 (Mig-6) has been identified as a negative regulator of the epidermal growth factor receptor (EGFR). Cartilage-specific Mig-6 knockout (KO) mice display increased EGFR signaling, an anabolic buildup of the articular cartilage, and formation of chondro-osseous nodules. Since our understanding of the EGFR/Mig-6 network in the cartilage remains incomplete, we characterized mice with cartilage-specific overexpression of Mig-6 in this study.

Methods

Utilizing knee joints from cartilage-specific Mig-6-overexpressing (Mig-6^over/over) mice (at multiple time points), we evaluated the articular cartilage using histology, immunohistochemical staining, and semi-quantitative histopathological scoring (OARSI) at multiple ages. MicroCT analysis was employed to examine skeletal morphometry, body composition, and bone mineral density.

Results

Our data show that cartilage-specific Mig-6 overexpression did not cause any major developmental abnormalities in the articular cartilage, although Mig-6^over/over mice have slightly shorter long bones compared to the control group. Moreover, there was no significant difference in bone mineral density and body composition in any of the groups. However, our results indicate that Mig-6^over/over male mice show accelerated cartilage degeneration at 12 and 18 months of age. Immunohistochemistry for SOX9 demonstrated that the number of positively stained cells in Mig-6^over/over mice was decreased relative to controls. Immunostaining for MMP13 appeared increased in areas of cartilage degeneration in Mig-6^over/over mice. Moreover, staining for phospho-EGFR (Tyr-1173) and lubricin (PRG4) was decreased in the articular cartilage of Mig-6^over/over mice.

Conclusion

Overexpression of Mig-6 in the articular cartilage causes no major developmental phenotype; however, these mice develop earlier OA during aging. These data demonstrate that Mig-6/EGFR pathways are critical for joint homeostasis and might present a promising therapeutic target for OA.

Interleukin-6 (IL-6) Activates the NOTCH1 Signaling Pathway Through E-Proteins in Endometriotic Lesions

CONTEXT

NOTCH signaling is activated in endometriotic lesions, but the exact mechanisms remains unclear. IL-6, which is increased in the peritoneal fluid of women with endometriosis, induces NOTCH1 through E-proteins including E2A and HEB in cancer.

OBJECTIVE

To study the role of E-proteins in inducing NOTCH1 expression under the regulation of IL-6 in endometriosis.

SETTING AND DESIGN

The expression of E-proteins and NOTCH1 was first investigated in endometrium of women with endometriosis and the baboon model of endometriosis. Regulation of E-proteins and NOTCH1 expression was examined after IL-6 stimulation and siRNA mediated inhibition of E2A or/and HEB in human endometriotic epithelial cells (12Z) in vitro, and subsequently following IL-6 treatment in the mouse model of endometriosis in vivo.

RESULTS

E2A, HEB, and NOTCH1 were significantly upregulated in glandular epithelium (GE) of ectopic endometrium compared to eutopic endometrium in both women and the baboon model. IL-6 treatment upregulated the expression of NOTCH1 together with E2A and HEB in 12Z cells. Small interfering RNA inhibition of E2A and HEB or HEB alone decreased NOTCH1 expression. Binding efficiency of both E2A and HEB was significantly higher at the binding sites on the human NOTCH1 promoter after IL-6 treatment. Finally, IL-6 treatment resulted in a significantly increased number of endometriotic lesions along with increased expression of E2A, HEB, and NOTCH1 in GE of the lesions compared with the vehicle group in an endometriosis mouse model.

CONCLUSIONS

IL-6 induced NOTCH1 expression is mediated by E-proteins in the ectopic GE cells, which may promote endometriotic lesion development.

Loss of HDAC3 results in nonreceptive endometrium and female infertility

Endometriosis is a disease in which tissue that normally grows inside the uterus grows outside the uterus and causes chronic pelvic pain and infertility. However, the exact mechanisms of the pathogenesis of endometriosis-associated infertility are unknown. Epigenetic dysregulation has recently been implicated in infertility. Here, we report a reduction of histone deacetylase 3 (HDAC3) protein amounts in eutopic endometrium of infertile women with endometriosis compared to a control group. To investigate the effect of HDAC3 loss in the uterus, we generated mice with conditional ablation of Hdac3 in progesterone receptor (PGR)-positive cells (Pgr^cre/+Hdac3^f/f ; Hdac3^d/d ). Loss of Hdac3 in the uterus of mice results in infertility due to implantation failure and decidualization defect. Expression microarray and ChIP-seq analyses identified COL1A1 and COL1A2 as direct targets of HDAC3 in both mice and humans. Reduction of HDAC3 abrogated decidualization in a primary culture of human endometrial stromal cells (hESCs) similar to that observed in infertile patients with endometriosis. Whereas attenuation of HDAC3 resulted in p300 recruitment to Col1a1 and Col1a2 genes in the uterus of mice as well as hESCs, inhibition of p300 permitted hESCs to undergo decidualization. Collectively, we found attenuation of HDAC3 and overexpression of collagen type I in the eutopic endometrium of infertile patients with endometriosis. HDAC3 loss caused a defect of decidualization through the aberrant transcriptional activation of Col1a1 and Col1a2 genes in mice and COL1A1 and COL1A2 genes in humans. Our results suggest that HDAC3 is critical for endometrial receptivity and decidualization.

Proline-Rich Acidic Protein 1 (PRAP1) is a Target of ARID1A and PGR in the Murine Uterus

ARID1A and PGR plays an important role in embryo implantation and decidualization during early pregnancy. Uterine specific Arid1a knockout (Pgr^cre/+Arid1a^f/f) mice exhibit in non-receptive endometrium at day 3.5 of gestation (GD 3.5). In previous studies, using transcriptomic analysis in the uterus of Pgr^cre/+Arid1a^f/f mice, we identified proline-rich acidic protein 1 (PRAP1) as one of the down-regulated genes by ARID1A in the uterus. In the present study, we performed RT-qPCR and immunohistochemistry analysis to investigate the regulation of PRAP1 by ARID1A and determine expression patterns of PRAP1 in the uterus during early pregnancy. During early pregnancy, PRAP1 expression was strong at day 0.5 of gestation (GD 0.5) and then decreased at GD 3.5 in the epithelium and stroma. After implantation, PRAP1 expression was remarkably reduced in the uterus. However, the expression of PRAP1 at GD 3.5 was remarkably increased in the Pgr^cre/+Arid1a ^f/f mice. To determine the ovarian steroid hormone regulation of PRAP1, we examined the expression of PRAP1 in ovariectomized control, Pgr^cre/+Arid1a^f/f, and progesterone receptor knock-out (PRKO) mice treated with progesterone. While PRAP1 proteins were strongly expressed in the luminal and glandular epithelium of control mice treated with vehicle, progesterone treatment suppressed the expression of PRAP1. However, PRAP1 was not suppressed in both the Pgr^cre/+Arid1a^f/f and PRKO mice compared to controls. Our results identified PRAP1 as a novel target of ARID1A and PGR in the murine uterus.

Unexplained recurrent pregnancy loss and unexplained infertility: twins in disguise

STUDY QUESTION

Is B-cell CLL/lymphoma 6 (BCL6) endometrial expression, a surrogate biomarker of endometriosis, elevated in women with unexplained recurrent pregnancy loss (uRPL) and unexplained infertility (UI) compared to fertile subjects?

SUMMARY ANSWER

Endometrial BCL6 expression is elevated to a similar degree in women with uRPL and UI compared to fertile controls.

WHAT IS KNOWN ALREADY

Endometriosis has been linked to the genesis of endometrial progesterone resistance and to specific nuclear proteins, including endometrial BCL6. BCL6 overexpression (immune histologic score > 1.4) has been strongly associated with poor reproductive outcomes in IVF cycles in women with UI. Our previous data have demonstrated an accuracy of 94% for diagnosing endometriosis, and BCL6 protein is elevated in the decidua of women with uRPL.

STUDY DESIGN SIZE DURATION

In this case-control study, at a tertiary university teaching hospital, 110 samples (control n = 28; uRPL n = 29; UI n = 53) from pathological archives were analyzed. Timed endometrial biopsies were obtained between 2 January 2002 and 31 December 2016.

PARTICIPANTS/MATERIALS SETTING METHOD

LH-timed endometrial biopsies were obtained from women with UI, uRPL (two or more consecutive losses) and normal fertile subjects during the mid-secretory phase of the menstrual cycle. Endometrial BCL6 protein levels were compared in women with UI and uRPL and fertile controls using western blot analysis and immunohistochemistry (HSCORE).

MAIN RESULTS AND THE ROLE OF CHANCE

The mean age of the uRPL group was significantly higher than the others [mean (SD)] control = 32.7 (2.6); uRPL = 35.8 (3.7); UI = 32.7 (4.4); P = 0.002, ANOVA]. Seventy-nine percent of women in both subfertile groups (uRPL and UI, 65 out of 82) displayed elevated BCL6 protein levels. From these, a subset of cases with abnormal BCL6 went to laparoscopy and endometriosis was found in 9 out of 11 cases of uRPL and in 20 out of 21 cases of UI. Median BCL6 HSCORE for controls versus uRPL and UI was significantly different [median (interquartile); control = 0.3 (0.02 to 0.5); uRPL = 3 (1.9 to 3.6); UI = 2.9 (1.6 to 3.1); P < 0.0001, Kruskal-Wallis]. A significant trend in the association between the degree of infertility (fertile, uRPL and UI) and the HSCORE level (negative, medium and high) was found (P < 0.001; x 2 for trend). Western blot of representative samples from each group demonstrated similar findings based on protein levels in the whole endometrium. After running ANCOVA analysis for age difference, the BCL6 difference among groups was still significant (P-value < 0.0001).

LIMITATIONS REASONS FOR CAUTION

We studied subjects with two consecutive pregnancy losses rather than the definition adopted in Europe of three losses. The findings may lack external validity in other clinical settings (e.g. low prevalence of endometriosis).

WIDER IMPLICATIONS OF THE FINDINGS

Based on the data presented here, we postulate that the degree of BCL6 expression may represent a continuum of progesterone resistance and response to inflammation that occurs in women with endometriosis, yielding different degrees of infertility, from uRPL to UI.

STUDY FUNDING/COMPETING INTERESTS

This study was supported by NICHD/NIH R01 HD067721 (SLY and BAL), by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior: Grant 99999.003035/2015-08 (BAL) and by CAPES/PROAP (RFS). Two authors (BAL, SLY) have licensed intellectual property for the detection of endometriosis. Dr Bruce Lessey is an unpaid scientific Advisor for CiceroDx. The other authors report no conflict of interest.

The impact of social media on citation rates in coloproctology

AIM

This study aimed to investigate the association between Twitter exposure and the number of citations for coloproctology articles.

METHOD

Original articles from journals using Twitter between June 2015 and May 2016 were evaluated for the following characteristics: publishing journal; article subject; study design; nationality, speciality and affiliation of the author(s); and reference on Twitter. Citation data for these articles were retrieved from Google Scholar (https://scholar.google.com) in January 2018. We performed a univariate analysis using these data followed by a multivariate, logistic regression analysis to search for factors associated with a high citation level, which was defined as accrual of more than five citations.

RESULTS

Out of six coloproctology journals listed on the InCites JCR database, three (Diseases of the Colon & Rectum, Colorectal Disease and Techniques in Coloproctology) used Twitter, where 200 (49.5%) out of a total of 404 articles had been featured. Citation rates of articles that featured on Twitter were significantly higher than those that did not (11.4 ± 9.2 vs 4.1 ± 3.1, P < 0.001). In multivariate analysis, Twitter exposure (OR 8.6, P = 0.001), European Union nationality (OR 2.4, P = 0.004), Colorectal Disease journal (OR 3.3, P = 0.005) and systematic review articles (OR 3.4, P = 0.009) were associated with higher citation levels.

CONCLUSION

Article exposure on Twitter was strongly associated with a high citation level. Medical communities should encourage journals as well as physicians to actively utilize social media to expedite the spread of new ideas and ultimately benefit medical society as a whole.

G-protein coupled receptor 64 (GPR64) acts as a tumor suppressor in endometrial cancer

BACKGROUND

Endometrial cancer is the most common gynecological cancer. G-protein coupled receptor 64 (GPR64) belongs to a family of adhesion GPCRs and plays an important role in male fertility. However, the function of GPR64 has not been studied in endometrial cancer. Our objective is to investigate the role of GPR64 in endometrial cancer.

METHODS

We examined the levels of GPR64 in human endometrioid endometrial carcinoma by immunohistochemistry analysis. To determine a tumor suppressor role of GPR64 in endometrial cancer, we used a siRNA loss of function approach in human endometrial adenocarcinoma cell lines.

RESULTS

GPR64 levels were remarkably lower in 10 of 21 (47.62%) of endometrial carcinoma samples compared to control. Depletion of GPR64 by siRNA transfection revealed an increase of colony formation ability, cell proliferation, cell migration, and invasion activity in Ishikawa and HEC1A cells. The expression of Connexin 43 (Cx43), a member of the large family of gap junction proteins, was reduced through activation of AMP-activated protein kinase (AMPK) in Ishikawa cells with GPR64-deficicy.

CONCLUSIONS

These results suggest that GPR64 plays an important tumor suppressor role in endometrial cancer.

Progesterone and Estrogen Signaling in the Endometrium: What Goes Wrong in Endometriosis?

In the healthy endometrium, progesterone and estrogen signaling coordinate in a tightly regulated, dynamic interplay to drive a normal menstrual cycle and promote an embryo-receptive state to allow implantation during the window of receptivity. It is well-established that progesterone and estrogen act primarily through their cognate receptors to set off cascades of signaling pathways and enact large-scale gene expression programs. In endometriosis, when endometrial tissue grows outside the uterine cavity, progesterone and estrogen signaling are disrupted, commonly resulting in progesterone resistance and estrogen dominance. This hormone imbalance leads to heightened inflammation and may also increase the pelvic pain of the disease and decrease endometrial receptivity to embryo implantation. This review focuses on the molecular mechanisms governing progesterone and estrogen signaling supporting endometrial function and how they become dysregulated in endometriosis. Understanding how these mechanisms contribute to the pelvic pain and infertility associated with endometriosis will open new avenues of targeted medical therapies to give relief to the millions of women suffering its effects.

Comparison of body surface area-based and weight-based dosing format for oral prednisolone administration in small and large-breed dogs

This study compared the pharmacokinetics of Prednisolone (PDS) in small- and large breed dogs with a dosing format based on body surface area (BSA) or body weight (BW). The maximum concentration and area under the curve in large-breed dogs orally administered 2 mg/kg PDS were significantly greater than those in small-breed dogs given 2 mg/kg and in large-breed dogs given 40 mg/m2. The higher blood concentrations that result from BW-based dosing of oral PDS in large-breed dogs can be more than required for effect. Meanwhile, BSA dosing at 40 mg/m may be suboptimal. These findings confirm important differences between standard PDS dosing schemes in dogs while highlighting the need to further optimize PDS dosing in large-breed dogs.

SOX17 regulates uterine epithelial-stromal cross-talk acting via a distal enhancer upstream of Ihh

Mammalian pregnancy depends on the ability of the uterus to support embryo implantation. Previous studies reveal the Sox17 gene as a downstream target of the Pgr-Gata2-dependent transcription network that directs genomic actions in the uterine endometrium receptive for embryo implantation. Here, we report that ablating Sox17 in the uterine epithelium impairs leukemia inhibitory factor (LIF) and Indian hedgehog homolog (IHH) signaling, leading to failure of embryo implantation. In vivo deletion of the SOX17-binding region 19 kb upstream of the Ihh locus by CRISPR-Cas technology reduces Ihh expression specifically in the uterus and alters proper endometrial epithelial-stromal interactions, thereby impairing pregnancy. This SOX17-binding interval is also bound by GATA2, FOXA2, and PGR. This cluster of transcription factor binding is common in 737 uterine genes and may represent a key regulatory element essential for uterine epithelial gene expression.

The Notch Family Transcription Factor, RBPJκ, Modulates Glucose Transporter and Ovarian Steroid Hormone Receptor Expression During Decidualization

During decidualization, endometrial stromal cells differentiate into a secretory phenotype to modulate the uterine microenvironment and promote embryo implantation. This highly metabolic process relies on ovarian steroid receptors and glucose transporters. Canonical Notch signaling is mediated by the transcription factor Recombination Signal Binding Protein for Immunoglobulin Kappa J Region (RBPJ). Loss of RBPJ in the mouse uterus (Pgr^cre/+Rbpj^flox/flox; Rbpj c-KO) results in subfertility in part due to an abnormal uterine-embryonic axis during implantation and, as described herein, decidualization failure. Induced in vivo decidualization in Rbpj c-KO mice was impaired with the downregulation of decidual markers and decreased progesterone receptor (Pgr) signaling. Consistent with in vivo mouse data, RBPJ knockdown during in vitro Human uterine fibroblast (HuF) cell decidualization results in the reduced expression of decidual marker genes along with PGR. Expression of the glucose transporter, SLC2A1, was decreased in the RBPJ-silenced HuF cells, which corresponded to decreased Slc2a1 in the secondary decidual zone of Rbpj c-KO mouse uteri. Exogenous administration of pyruvate, which bypasses the need for glucose, rescues PRL expression in RBPJ-deficient HuF cells. In summary, Notch signaling through RBPJ controls both ovarian steroid receptor PGR and glucose transporter SLC2A1 expression during decidualization, and this dysregulation likely contributes to embryo implantation failure.

Abstract 5501: The role of G-protein coupled receptor 64 (GPR64) as a tumor suppressor in endometrial cancer

Endometrial cancer is the most common gynecologic cancer. G-protein coupled receptor 64 (GPR64) belongs to a family of adhesion GPCRs and plays an important role for male fertility. However, GPR64 function has not been reported in endometrial cancer. Our objective is to investigate the role of GPR64 in endometrial cancer. We examined the levels of GPR64 in human endometrial cancer tissue by immunohistochemistry analysis. GPR64 levels were significantly lower in 10 of 21 (47.62%) of endometrial carcinoma samples compared to control. To test whether GPR64 has a role of tumor suppressor in endometrial cancer, we used an siRNA loss-of-function approach in human endometrial adenocarcinoma cell lines. Depletion of GPR64 by siRNA transfection in Ishikawa and HEC1A cells showed an increase of colony formation ability and cell proliferation. Depletion of GPR64 also significantly increased the migration and invasion activity of Ishikawa and HEC1A cells. Furthermore, the phosphorylation of AMP-activated protein kinase (AMPK) and expression of Connexin 43 (Cx43), a member of the large family of gap junction proteins, were regulated in GPR64-deficient Ishikawa cells. These results suggest that GPR64 plays an important role for cell proliferation, migration, and invasion as a tumor suppressor in endometrial cancer.

Citation Format: Jung-Yoon Yoo, Jong Il Ahn, Tae Hoon Kim, Russell R. Broaddus, Jeong Mook Lim, Ho-Geun Yoon, Jae-Wook Jeong. The role of G-protein coupled receptor 64 (GPR64) as a tumor suppressor in endometrial cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5501.

Mitochondrial tumor suppressor 1 is a target of AT-rich interactive domain 1A and progesterone receptor in the murine uterus

Objective

Progesterone receptor (PGR) and AT-rich interactive domain 1A (ARID1A) have important roles in the establishment and maintenance of pregnancy in the uterus. In present studies, we examined the expression of mitochondrial tumor suppressor 1 (MTUS1) in the murine uterus during early pregnancy as well as in response to ovarian steroid hormone treatment.

Methods

We performed quantitative reverse transcription polymerase chain reaction and immunohistochemistry analysis to investigate the regulation of MTUS1 by ARID1A and determined expression patterns of MTUS1 in the uterus during early pregnancy.

Results

The expression of MTUS1 was detected on day 0.5 of gestation (GD 0.5) and then gradually increased until GD 3.5 in the luminal and glandular epithelium. However, the expression of MTUS1 was significantly reduced in the uterine epithelial cells of Pgr^cre/+Arid1a^f/f and Pgr knockout (PRKO) mice at GD 3.5. Furthermore, MTUS1 expression was remarkably induced after P4 treatment in the luminal and glandular epithelium of the wild-type mice. However, the induction of MTUS1 expression was not detected in uteri of Pgr^cre/+Arid1a^f/f or PRKO mice treated with P4.

Conclusion

These results suggest that MTUS1 is a novel target gene by ARID1A and PGR in the uterine epithelial cells.

Expression of PIK3IP1 in the murine uterus during early pregnancy

The ovarian steroid hormones, estrogen (E2) and progesterone (P4), are essential regulators of uterine functions necessary for development, embryo implantation, and normal pregnancy. ARID1A plays an important role in steroid hormone signaling in endometrial function and pregnancy. In previous studies, using high density DNA microarray analysis, we identified phosphatidylinositol-3-kinase interacting protein 1 (Pik3ip1) as one of the genes up-regulated by ARID1A. In the present study, we performed real-time qPCR and immunohistochemistry analysis to investigate the regulation of PIK3IP1 by ARID1A and determine expression patterns of PIK3IP1 in the uterus during early pregnancy. The expression of PIK3IP1 was strong at the uterine epithelial and stromal cells of the control mice. However, expression of PIK3IP1 was remarkably reduced in the Pgr^cre/+Arid1a^f/f mice and progesterone receptor knock-out (PRKO) mice. During early pregnancy, PIK3IP1 expression was strong at day 2.5 of gestation (GD 2.5) and then slightly decreased at GD 3.5 at the epithelium and stroma. After implantation, PIK3IP1 expression was detected at the secondary decidualization zone. To determine the ovarian steroid hormone regulation of PIK3IP1, we examined the expression of PIK3IP1 in ovariectomized control, Pgr^cre/+Arid1a^f/f, and PRKO mice treated with P4 or E2. P4 treatment increased the PIK3IP1 expression at the luminal and glandular epithelium of control mice. However, the PIK3IP1 induction was decreased in both the Pgr^cre/+Arid1a^f/f and PRKO mice, compared to controls. Our results identified PIK3IP1 as a novel target of ARID1A and PGR in the murine uterus.

Pik3ca is required for mouse uterine gland development and pregnancy

The PI3K/AKT signaling pathway plays a critical role in the maintenance of equilibrium between cell survival and apoptosis. The Pik3ca gene is mutated in a range of human cancers. It has been found to be oncogenic, and mutations lead to constitutive activation of the PI3K/AKT pathway. The expression patterns of PIK3CA proteins in the uterus of mice during early pregnancy indicate that it may play a role in the regulation of glandular epithelial cells, which is required to support uterine receptivity. To further investigate the role of Pik3ca in uterine function, Pik3ca was conditionally ablated only in the PGR-positive cells (Pgr^cre/+Pik3ca^f/f; Pik3ca^d/d). A defect of uterine gland development and decidualization led to subfertility observed in Pik3ca^d/d mice. Pik3ca^d/d mice showed significantly decreased uterine weight compared to Pik3ca^f/f mice. Interestingly, a significant decrease of gland numbers were detected in Pik3ca^d/d mice compared to control mice. In addition, we found a decrease of Foxa2 expression, which is a known uterine gland marker in Pik3ca^d/d mice. Furthermore, the excessive proliferation of endometrial epithelial cells was observed in Pik3ca^d/d mice. Our studies suggest that Pik3ca has a critical role in uterine gland development and female fertility.

RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss

Unexplained recurrent pregnancy loss (uRPL) is associated with repeated embryo loss and endometrial repair with elevated endometrial expression of inflammatory cytokines, including IFN-γ. Notch signaling through its transcription factor recombination signal binding protein Jκ (RBPJ) regulates mechanisms including the immune response and repair after tissue injury. Initially, null mutation of RBPJ in the mouse uterus ( Pgr^cre/+Rbpj^f/f; Rbpj c-KO) results in subfertility, but we have found that these mice become infertile after pregnancy as a result of dysfunctional postpartum uterine repair, including delayed endometrial epithelial and myometrial regeneration. RNA sequencing of postpartum uterine repair sites revealed global up-regulation of inflammatory pathways, including IFN signaling. Consistent with elevated IFN-γ, macrophages were recruited and polarized toward an M1-cytotoxic phenotype, which is associated with preventing repair and promoting further tissue injury. Through embryo transfer experiments, we show that dysfunctional postpartum repair directly impairs future embryo implantation in Rbpj c-KO mice. Last, we clinically correlated our findings from the Rbpj c-KO mouse in women diagnosed with uRPL. Reduced RBPJ in women with uRPL was associated with increased levels of IFN-γ. The data, taken together, indicate that RBPJ regulates inflammation during endometrial repair, which is essential for future pregnancy potential, and its dysregulation may serve as an unidentified contributor to uRPL in women.-Strug, M. R., Su, R.-W., Kim, T. H., Mauriello, A., Ticconi, C., Lessey, B. A., Young, S. L., Lim, J. M., Jeong, J.-W., Fazleabas, A. T. RBPJ mediates uterine repair in the mouse and is reduced in women with recurrent pregnancy loss.

Triazolium cyclodextrin click cluster-resin conjugate: an enrichment material for phosphatidylinositol (3,4,5)-triphosphate

UltraLink was functionalized with a triazolium cyclodextrin click cluster (CCC) which provides a well-oriented, multivalent, positively charged binding site for PtdIns(3,4,5)P₃. MALDI TOF MS and LC ESI MS/MS MRM analysis of spiked PtdIns(3,4,5)P₃ in lipid extract suggest that triazolium CCC-UltraLink conjugate can be used as an enrichment material for PtdIns(3,4,5)P₃.

KRAS Activation and over-expression of SIRT1/BCL6 Contributes to the Pathogenesis of Endometriosis and Progesterone Resistance

Endometriosis is an inflammatory condition that is associated with progesterone resistance and cell proliferation, resulting in pain, infertility and pregnancy loss. We previously demonstrated phosphorylation of STAT3 in eutopic endometrium of infertile women with this disorder leading to over-expression of the oncogene BCL6 and stabilization of hypoxia-induced factor 1 alpha (HIF-1α). Here we report coordinated activation of KRAS and over-expression of Sirtuin 1 (SIRT1), a histone deacetylase and gene silencer, in the eutopic endometrium from women with endometriosis throughout the menstrual cycle. The mice with conditional activation of KRAS in the PGR positive cells reveal an increase of SIRT1 expression in the endometrium compared to control mice. The expression of progesterone receptor target genes including the Indian Hedgehog pathway genes are significantly down-regulated in the mutant mice. SIRT1 co-localizes with BCL6 in the nuclei of affected individuals and both proteins bind to and suppress the promoter of GLI1, a critical mediator of progesterone action in the Indian Hedgehog pathway, by ChIP analysis. In eutopic endometrium, GLI1 expression is reduced in women with endometriosis. Together, these data suggest that KRAS, SIRT1 and BCL6 are coordinately over-expressed in eutopic endometrium of women with endometriosis and likely participate in the pathogenesis of endometriosis.

G-protein coupled receptor 64 is required for decidualization of endometrial stromal cells

Although GPR64 has an important role for male fertility, its physiological roles in the female reproductive system are still unknown. In the present study, immunohistochemical analysis reveals a spatiotemporal expression of GPR64 in the uterus during early pregnancy. Observation of remarkable induction of GPR64 expression in uterine decidual cells points to its potential physiological significance on decidualization. The decidualization of uterine stromal cells is a key event in implantation. Progesterone (P4) signaling is crucial for the decidualization of the endometrial stromal cells for successful pregnancy. Therefore, we examined ovarian steroid hormone regulation of GPR64 expression in the murine uterus. P4 induced GPR64 expression in the epithelial and stromal cells of the uterus in ovariectomized wild-type mice, but not in PRKO mice. ChIP analysis confirmed that PGR proteins were recruited on progesterone response element of Gpr64 gene in the uteri of wild-type mice treated with P4. Furthermore, the expression of GPR64 was increased in human endometrial stromal cells (hESCs) during in vitro decidualization. Interestingly, small interfering RNA (siRNA)-mediated knockdown of GPR64 in hESCs remarkably reduced decidualization. These results suggest that Gpr64 has a crucial role in the decidualization of endometrial stromal cells.

Overexpression of Four Joint Box-1 Protein (FJX1) in Eutopic Endometrium From Women With Endometriosis

The four jointed box 1 (FJX1) is a regulator of angiogenesis, and the levels of FJX1 are increased in several types of cancer. Angiogenesis plays a critical role in endometrial growth as well as in several gynecologic disorders including endometriosis. However, the function of FJX1 has not been studied in endometriosis. Therefore, we examined the levels of FJX1 in eutopic endometrium from women with or without endometriosis. The levels of FJX1 protein did not change in endometrial cells during the menstrual cycle in endometrium from women without endometriosis. However, its levels were significantly higher in the secretory phase of the eutopic endometrium from women with endometriosis when compared to women without endometriosis. Hypoxia-inducible factor-1α (HIF1α) is known as a key mediator of endometriosis by regulating genes essential to estrogen production, angiogenesis, proliferation, inflammation, and extracellular invasion. It has been reported that FJX1 induces an increase in HIF1α through posttranslational stabilization. The results of our Western blot analysis reveal a significant positive correlation between FJX1 and HIF1α proteins in endometrium of women with and without endometriosis. This overexpression of FJX1 was confirmed by sequential analysis of the eutopic endometrium during endometriosis progression, using an induced model of endometriosis in the baboon. Therefore, our results suggest that high levels of FJX1 proteins may play an important role in the pathogenesis of endometriosis.

Progesterone Resistance in Endometriosis Is Modulated by the Altered Expression of MicroRNA-29c and FKBP4

CONTEXT

Endometriosis results in aberrant gene expression in the eutopic endometrium (EuE) and subsequent progesterone resistance. MicroRNA (miR) microarray data in a baboon model of endometriosis showed an increased expression of miR-29c.

OBJECTIVES

To explore the role of miR-29c in progesterone resistance in a subset of women with endometriosis.

DESIGN

MiR-29c expression was analyzed in the endometrium of baboons and women with or without endometriosis. The role in progesterone resistance and decidualization was analyzed by transfecting human uterine fibroblast cells with miR-29c.

PATIENTS

Subjects diagnosed with deep infiltrative endometriosis (DIE) by transvaginal ultrasound with bowel preparation underwent surgical excision of endometriosis. Eutopic secretory endometrium was collected pre- and postoperatively. Women with normal EuE and without DIE served as controls.

RESULTS

Quantitative reverse transcription polymerase chain reaction demonstrated that miR-29c expression increased, while the transcript levels of its target, FK506-binding protein 4 (FKBP4), decreased in the EuE of baboons following the induction of endometriosis. FKBP4 messenger RNA and decidual markers were statistically significantly decreased in decidualized human uterine fibroblast cells transfected with a miR-29c mimic compared with controls. Human data corroborated our baboon data and demonstrated higher expression of miR-29c in endometriosis EuE compared with normal EuE. MiR-29c was significantly decreased in endometriosis EuE postoperatively compared with preoperative tissues, and FKBP4 showed an inverse trend following radical laparoscopic resection surgery.

CONCLUSIONS

We demonstrate that miR-29c expression is increased in EuE of baboons and women with endometriosis, which might contribute to a compromised progesterone response by diminishing the levels of FKBP4. Resection of DIE is likely to reverse the progesterone resistance associated with endometriosis in women.

Mig-6 Mouse Model of Endometrial Cancer

Endometrial cancer is a frequently occurring gynecological disorder. Estrogen-dependent endometrioid carcinoma is the most common type of gynecological cancer. One of the major pathologic phenomena of endometrial cancer is the loss of estrogen (E2) and progesterone (P4) control over uterine epithelial cell proliferation. P4 antagonizes the growth-promoting properties of E2 in the uterus. P4 prevents the development of endometrial cancer associated with unopposed E2 by blocking E2 actions. Mitogen inducible gene 6 (Mig-6, Errfi1, RALT, or gene 33) is an immediate early response gene that can be induced by various mitogens and common chronic stress stimuli. Mig-6 has been identified as an important component of P4-mediated inhibition of E2 signaling in the uterus. Decreased expression of MIG-6 is observed in human endometrial carcinomas. Transgenic mice with Mig-6 ablation in the uterus develop endometrial hyperplasia and E2-dependent endometrial cancer. Thus, MIG-6 has a tumor suppressor function in endometrial tumorigenesis. The following discussion summarizes our current knowledge of Mig-6 mouse models and their role in understanding the molecular mechanisms of endometrial tumorigenesis and in the development of therapeutic approaches for endometrial cancer.

Pharmacokinetic study of meropenem in healthy beagle dogs receiving intermittent hemodialysis

Meropenem, a second carbapenem antimicrobial agent with a broad spectrum of activity, is used to treat sepsis and resistant-bacterial infections in veterinary medicine. The objective of this study was to identify the pharmacokinetics of meropenem in dogs receiving intermittent hemodialysis (IHD) and to determine the proper dosing in renal failure patients receiving IHD. Five healthy beagle dogs were given a single i.v. dose of 24 mg/kg of meropenem and received IHD. The blood flow rate, dialysate flow, and ultrafiltration rate were maintained at 40 mL/min, 300 mL/min, and 40 mL/h, respectively. Blood samples were collected for 24 h from the jugular vein and from the extracorporeal arterial and venous line. Urine samples and dialysate were also collected. The concentrations of meropenem were assayed using HPLC/MS/MS determination. The peak plasma concentration was 116 ± 37 μg/mL at 15 min. The systemic clearance was 347 ± 117 mL/h/kg, and the steady-state volume of distribution was 223 ± 67 mL/kg. Dialysis clearance was 71.1 ± 34.3 mL/h/kg, and the extraction ratio by hemodialysis was 0.455 ± 0.150. The half-life (T_1/2 ) in dogs with IHD decreased compared with those without IHD, and the reduction in T_1/2 was greater in renal failure patients than in normal patients. Sixty-nine percent and 21% of the administered drug were recovered by urine and dialysate in the unchanged form, respectively. In conclusion, additional dosing of 24 mg/kg of meropenem after dialysis could be necessary according to the residual renal function of the patient based on the simulated data.

Abstract 3674: MIG-6 suppresses epithelial cell proliferation via inhibiting AKT phosphorylation during endometrial tumorigenesis

Endometrial cancer is the most frequently diagnosed malignancy of the female genital tract. Hysterectomy is typically the first line therapeutic strategy for endometrial cancer. However, there is an increasing demand for nonsurgical approaches for endometrial cancer, especially for women of reproductive age with endometrial cancer who wish to preserve their fertility. Most endometrial cancers are characterized by actively proliferating epithelial cells, increased AKT signaling and association with prolonged, unopposed E2 exposure.

Mitogen-inducible gene 6 (Mig-6) is an important mediator of progesterone receptor action in the murine uterus. As P4 achieves the inhibition of proliferation by coordinating stromal-epithelial cross-talk, we generated a mouse model in which we specifically ablate epithelial endometrial Mig-6 using Sprr2f-cre mice (Sprr2fcre+Mig-6f/f) to understand the role of epithelial Mig-6 in the uterus. Sprr2fcre+Mig-6f/f mice displayed endometrial hyperplasia upon 10 weeks of age and develop endometrial cancer by E2 treatment for 3 months. The levels of epithelial proliferation by Ki67 staining were significantly increased in epithelial cells of Sprr2fcre+Mig-6f/f mice at 10 weeks of age. The levels of phospho-AKT and phospho-S6, downstream of AKT, were remarkably higher in Sprr2fcre+Mig-6f/f mice. Interestingly, the hyperplasia exhibited by Sprr2fcre+Mig-6f/f mice was prevented by P4 treatment for 1 week in morphological and histological analysis. Aberrant activation of proliferation as well as AKT signaling was decreased in the epithelium of Sprr2fcre+Mig-6f/f mice by P4 treatment. Furthermore, we identified that MIG-6 inhibits AKT phosphorylation in human endometrial cancer cells. These data suggest that stromal P4 signaling including Mig-6 is critical in regulation of epithelial cell proliferation via regulating AKT phosphorylation during endometrial cancer development and progression.

(This work was supported by American Cancer Society Research Grant, RSG-12-084-01-TBG to J.W.J.)

Citation Format: Tae Hoon Kim, Jung-Yoon Yoo, Jae Hee Lee, Byung Gak Kim, Russell R. Broaddus, Jae-Wook Jeong. MIG-6 suppresses epithelial cell proliferation via inhibiting AKT phosphorylation during endometrial tumorigenesis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3674.