Stromal Progesterone Receptor Research Articles

Baseline breast tissue characteristics determine the effect of tamoxifen on mammographic density change.

Tamoxifen prevents recurrence of breast cancer and is also approved for preventive, risk-reducing, therapy. Tamoxifen alters the breast tissue composition and decreases the mammographic density. We aimed to test if baseline breast tissue composition influences tamoxifen-associated density change. This biopsy-based study included 83 participants randomised to 6 months daily intake of placebo, 20, 10, 5, 2.5, or 1 mg tamoxifen. The study is nested within the double-blinded tamoxifen dose-determination trial Karolinska Mammography Project for Risk Prediction of Breast Cancer Intervention (KARISMA) Study. Ultrasound-guided core-needle breast biopsies were collected at baseline before starting treatment. Biopsies were quantified for epithelial, stromal, and adipose distributions, and epithelial and stromal expression of proliferation marker Ki67, oestrogen receptor (ER) and progesterone receptor (PR). Mammographic density was measured using STRATUS. We found that greater mammographic density at baseline was positively associated with stromal area and inversely associated with adipose area and stromal expression of ER. Premenopausal women had greater mammographic density and epithelial tissue, and expressed more epithelial Ki67, PR, and stromal PR, compared to postmenopausal women. In women treated with tamoxifen (1-20 mg), greater density decrease was associated with higher baseline density, epithelial Ki67, and stromal PR. Women who responded to tamoxifen with a density decrease had on average 17% higher baseline density and a 2.2-fold higher PR expression compared to non-responders. Our results indicate that features in the normal breast tissue before tamoxifen exposure influences the tamoxifen-associated density decrease, and that the age-associated difference in density change may be related to age-dependant differences in expression of Ki67 and PR.

Insights into molecular pathways of endometriosis and endometriosis-related ovarian carcinoma.

Background: Endometriosis is a benign estrogen-dependent gynecological disease involving components of the female genital tract (uterus, Fallopian tubes, ovaries, large, round, and utero-sacral ligaments) and intra- and extraperitoneal regions. Since the moment of its etiopathogeny has been identified, the intrinsic capacity of endometriosis malignant transformation has been hypothesized. Patients, Materials and Methods: Our study included a total number of 50 patients diagnosed with endometriosis (31 cases) and endometriosis-related ovarian carcinoma (EOC) (19 cases). A clinicopathological and immunohistochemical study directed towards the detection of atypical transition lesions and the similitudes in epithelial–mesenchymal transition (EMT) phenomenon [E-cadherin/β-catenin/cytokeratin 18 (CK18)], apoptosis [B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X (Bax)], and hormonal dynamics mirrored by the immunoexpression of estrogen receptor (ER) and progesterone receptor (PR) in endometriosis and EOC glands and stroma has been performed. Results: Our study showed a higher immunoexpression of CK18 and E-cadherin in endometriosis than in neoplastic counterparts, while β-catenin had a stronger immunoexpression in tumors compared with endometriotic areas, with statistically significant differences between the studied groups. Bcl-2/Bax higher rate in endometriosis had a statistically significant association to a more aggressive tumor behavior (p=0.020). ER immunoexpression was stronger in endometriosis, with less negative scores compared to EOC, while PR immunoexpression was stronger in endometriosis, with a lower percent of negative scores compared to EOC. PR immunostaining was correlated to ovarian location of endometriosis (p=0.004) and tumor grade of EOC (p=0.027). Stromal ER and PR immunoexpression has been significantly lower in endometriosis in comparison to tumor stroma (p=0.001) and PR stromal immunoexpression had been higher in more differentiated tumors compared to less differentiated types (p=0.005). Conclusions: Our study supports that endometriosis is a precursor of EOC by the identification and the coexistence of both lesions in the investigated cases, the identification of intermediate lesions, as well as the expression of EMT immunomarkers, along with apoptosis and steroid receptors immunoexpression.

ASSOCIATION BETWEEN THE PERCENTAGE OF p16-POSITIVE SENESCENT CELLS AND THE EXPRESSION OF ESTROGEN AND PROGESTERONE RECEPTORS IN HUMAN ENDOMETRIUM DURING THE MID-LUTEAL PHASE

Progesterone and estrogen secretion and the expression of their receptors are strongly connected with the cyclic changes in endometrium and its receptivity. We previously reported that the frequency of occurrence of p16-positive senescent cells in human endometrium appear to be also associated with endometrial receptivity and successful embryo implantation. The objective of this study was to analyze the relationship between the percentage of senescent cells and estrogen and progesterone receptors expression in human endometrium during the mid-luteal phase of the menstrual cycle. Prospective observational study. This study includes 383 women who had an endometrial biopsy during the mid-lutheal phase (7 days after LH surge) of the natural cycles. Tissue sections were stained immunohistochemically for ER, PR and p16 using the following monoclonal antibodies: progesterone receptor (PR) (NCL-PGR-312, Leica Microsystems), 1:100 dilution; estrogen receptor (ER) (NCL-L-ER-6F11, Leica Microsystems), 1:100 dilution; p16 ink4a antibody (MAD-000690QD–7, Master Diagnostica), ready-to-use. The percentage of positively stained p16 cells and the levels of ER/PR expression were evaluated by Image-J software (NIH, Maryland, USA) in multiple endometrial sections. Statistical analysis was performed by Spearman’s correlation test using SPSS v.21 (IBM Corp., Armonk, NY, USA). No correlation was found between the frequencies of occurrence of senescent p16-positive stromal, luminal and glandular epithelial cells and PR (p>0.05). In contrast, the glandular expression of ER showed low, but a significant correlation with the percentage of p16+ glandular epithelial cells (R=0.34; p=0.03). In conclusion, we found that the increased cell senescence in endometrial glands during the mid-luteal phase is associated with increased expression of glandular ER in the mid-luteal phase of the cycle. These results suggest an estrogen related change of endometrial senescent cells during the period of embryo implantation.

Expression of Stromal Progesterone Receptor and Differential Methylation Patterns in the Endometrium May Correlate with Response to Progesterone Therapy in Endometrial Complex Atypical Hyperplasia

Progesterone therapy is a viable treatment for complex atypical hyperplasia (CAH) and endometrial adenocarcinoma, though reliable molecular determinants of response are not available. To explore if analysis of pre-therapy endometrial biopsies could yield biomarkers of response to progesterone, patients with CAH or adenocarcinoma undergoing treatment with progestins were included in this cross-sectional study. Immunohistochemistry for progesterone receptor (PR) was performed. Manual PR expression scores (PRES) were first calculated for biopsies by counting PR-positive nuclei in 12 sensitive vs 9 resistant samples. Significant differences in manual PRES were detected in the stroma (p < 0.01) and total endometrium (p < 0.01) for sensitive vs resistant patients. Manual PRES in the stroma had the highest accuracy in segregating sensitive vs resistant patients (96%). Differences in epithelial PRES were not significant. To validate these findings, a correlation between manual PRES and visual PRES was performed in the 21 patients. An additional 11 patients were analyzed to test if visual PRES would be predictive of response to progesterone. Visual PRES in epithelia and stroma in the 32 specimens was calculated. Significant differences in visual PRES were detected in the stroma for sensitive vs resistant samples (p < 0.01), while differences in epithelial and total endometrium were not significant. Whole genome bisulfite sequencing was performed on DNA isolated using pre-therapy biopsies from 6 sensitive and 6 resistant patients in this cohort. Differentially methylated regions were identified in the stroma and epithelium when evaluating sensitive vs resistant samples. Pathways involved in cell adhesion demonstrated the greatest difference in methylation in these samples.

Clinical significance of stromal ER and PR expression in periampullary adenocarcinoma

BackgroundTamoxifen treatment has previously been reported to confer life-prolonging effects in patients with advanced pancreatic cancer, and most evidently so in women. None of these trials did however include biomarkers, and the relevance of female hormone signaling in pancreatic or other periampullary adenocarcinoma remains largely unexplored. The aim of this study was to examine the extent and potential clinical significance of estrogen receptor-α (ER) and progesterone receptor (PR) expression in pancreatic and other periampullary cancers.MethodsER and PR expression was examined using immunohistochemistry on tissue microarrays with primary tumors from a retrospective consecutive cohort of 175 patients with resected periampullary adenocarcinoma, with long-term clinical follow-up. Non-parametric and Chi square tests were applied to examine the associations of stromal ER and PR expression with patient and tumor characteristics. Kaplan-Meier analysis and log rank test were applied to illustrate survival differences in relation to ER and PR expression. Cox regression proportional hazards models were applied to examine the associations between investigative factors and risk of death and recurrence, and to test for interactions between KRAS mutation status and hormone receptor expression in relation to survival.ResultsExpression of both ER and PR was more frequent in the tumor-associated stroma than in the epithelium. A significant prognostic interaction, independent of tumor morphology, was found between stromal PR expression and KRAS mutation status in relation to both overall and recurrence-free survival (pinteraction = 0.026 and pinteraction = 0.005), in particular in women (pinteraction = 0.002 and pinteraction = 0.005). Specifically, stromal PR expression was associated with a prolonged survival in patients with KRAS-mutated tumors, whereas the opposite was seen for KRAS wild-type tumors. The prognostic value of ER positivity was limited to the subgroup of women with tumors of pancreatic origin.ConclusionsThese results demonstrate that stromal PR rather than ER expression, together with KRAS mutation status, provides long-term prognostic information in patients with periampullary adenocarcinoma. Further study into the mechanistic basis for these observations may unveil important clues to the pathogenesis of these cancers and open up for the discovery of novel treatment options.

Analysis of the endometrial stroma may play an important role in predicting progestin response in complex atypical hyperplasia or grade I adenocarcinoma

Objective: To determine whether stromal progesterone receptor expression and differential methylation in pretherapy endometrial biopsies correlate with response to hormonal therapy in a subset of patients with complex atypical hyperplasia or grade 1 adenocarcinoma.

Endometrial biopsy in recurrent implantation failure: a histopathological and immunohistochemical study

Background Recurrent implantation failure (RIF) may be related to a defect in endometrial receptivity. There is still lack of data regarding the effect of progesterone on endometrial receptivity, namely, expression of adhesion molecules. This study aimed at investigating the endometrium for histopathological changes and expression of E-cadherin and progesterone receptors (PR). Patients and methods This study was conducted on 40 endometrial biopsies from patients with RIF compared with 10 biopsies from age-matched control. Biopsies were examined for pathological changes and immunostained with PR and E-cadherin. Results There was a statistically significant reduction in stromal PR in cases compared with control, but no statistically significant difference was found in glandular PR expression. A significant reduction in glandular E-cadherin expression was evident in cases. Conclusion Endometrial biopsy may have a role in investigating women with RIF. Maintained stromal PR acts to allow expression of adhesion molecules like E-cadherin and opening of implantation window.

769P - Stromal progesterone receptor expression and long-term survival in patients with resected periampullary adenocarcinoma

Background: Early trials have reported a beneficial effect from tamoxifen treatment in patients with unresectable pancreatic cancer, in particular in women. However, the presence and prognostic significance of female hormone receptors in pancreatic or other periampullary cancers has not yet been described. Methods: Immunohistochemical screening of normal and malignant pancreatic tissue revealed that the predominantly expressed female hormone receptor was the progesterone receptor (PgR), in particular in the cancer-associated stroma. The impact of PgR expression on overall survival (OS) was further examined on tissue microarrays with primary tumours from a consecutive retrospective cohort of 175 patients with resected periampullary adenocarcinoma. Results: Median follow-up time was 29.7 (range 1.9–185.1) months. Stromal PgR positivity (PgR+), allover denoted in 31% of the cases, was significantly higher in pancreatobiliary-type than in intestinal-type tumours (38.7% vs 19.0%, p = 0.008), with an equal distribution between sexes. Stromal PgR+ was significantly associated with a prolonged OS in KRAS-mutated tumours, whereas the opposite was seen in KRAS wild-type tumours (p for interaction =0.015). This association was particularly evident in women, with a median OS of 60.5 months for PgR+/KRAS mutated tumours and 9.9 months for PgR+/KRAS wild-type tumours (p for interaction <0.001). PgR expression was not prognostic in male patients. Conclusions: The finding of stromal PgR expression, and its link to clinical outcome in a considerable proportion of pancreatic and other periampullary cancers is novel. The concept of tamoxifen treatment for patients with unresectable disease, in particular elderly women, should be pursued, and PgR and KRAS may be relevant biomarkers for improved patient stratification. (Less)

MP57-18 EXPRESSION OF STEROID HORMONE RECEPTORS IN RESIDUAL CANCER AND STROMAL CELLS AFTER NEOADJUVANT CHEMOHORMONAL THERAPY WITH DOCETAXAL FOR HIGH-RISK LOCALIZED PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Localized: Surgical Therapy III1 Apr 2016MP57-18 EXPRESSION OF STEROID HORMONE RECEPTORS IN RESIDUAL CANCER AND STROMAL CELLS AFTER NEOADJUVANT CHEMOHORMONAL THERAPY WITH DOCETAXAL FOR HIGH-RISK LOCALIZED PROSTATE CANCER Shintaro Narita, Taketoshi Nara, Mingguo Huang, Koichiro Takayama, Kazuyuki Numakura, Hiroshi Tsuruta, Atsushi Maeno, Mitsuru Saito, Takamitsu Inoue, Norihiko Tsuchiya, Hiroshi Nanjo, Shigeru Satoh, and Tomonori Habuchi Shintaro NaritaShintaro Narita More articles by this author , Taketoshi NaraTaketoshi Nara More articles by this author , Mingguo HuangMingguo Huang More articles by this author , Koichiro TakayamaKoichiro Takayama More articles by this author , Kazuyuki NumakuraKazuyuki Numakura More articles by this author , Hiroshi TsurutaHiroshi Tsuruta More articles by this author , Atsushi MaenoAtsushi Maeno More articles by this author , Mitsuru SaitoMitsuru Saito More articles by this author , Takamitsu InoueTakamitsu Inoue More articles by this author , Norihiko TsuchiyaNorihiko Tsuchiya More articles by this author , Hiroshi NanjoHiroshi Nanjo More articles by this author , Shigeru SatohShigeru Satoh More articles by this author , and Tomonori HabuchiTomonori Habuchi More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.672AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Recent studies suggest that activation of steroid hormone receptors (SHRs) is associated with PCa progression and resistance to chemohormonal therapy. In this study, we investigated SHR expressions in human PCa tissues in patients who underwent radical prostatectomy (RP) with and without neoadjuvant chemohormonal therapy. METHODS A tissue microarray with 210 cores from 70 high-risk localized PCa patients who underwent RP without neoadjuvant therapy (NNA), with neoadjuvant hormonal therapy (NHT), or with neoadjuvant chemohormonal therapy with docetaxel (CHT) was used to assess the epithelial and stromal expressions of four SHRs including androgen receptor (AR), glucocorticoid receptor (GR), estrogen receptor (ER) alpha, and progesterone receptor (PR). Expression levels of SHRs between the three groups were statistically assessed. Multivariate analyses were performed to investigate the prognostic factors of BCR in patients who underwent surgery with CHT. RESULTS AR and GR were expressed in both residual cancer and stromal cells, whereas ER alpha and PR were mainly expressed in stromal cells. The mean nuclear AR immunoreactivity score in residual cancer cells was significantly higher in the NNA group than in the NHT and CHT groups. The mean nuclear GR immunoreactivity score in residual cancer cells and mean nuclear ER alpha and PR in stromal cells were significantly higher in the CHT group than in the NNA and NHT groups. The patients with a low PR immunoreactivity score in stromal cells had a significantly higher BCR rate than those with a high nuclear immunoreactivity score (p = 0.011). In multivariate analysis, the number of risk factors constituting the classification of high-risk, a preoperative PSA level, pathological chemotherapy effect, and low nuclear PR immunoreactivity score in stromal cells were independent prognostic factors for BCR. CONCLUSIONS Stromal PR expression may be a potential prognostic marker for BCR in high-risk PCa patients who underwent radical prostatectomy after neoadjuvant chemohormonal therapy. The expression of SHRs in both residual cancer and stromal cells may play an important role in PCa resistance to chemohormonal therapy. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e759-e760 Advertisement Copyright & Permissions© 2016MetricsAuthor Information Shintaro Narita More articles by this author Taketoshi Nara More articles by this author Mingguo Huang More articles by this author Koichiro Takayama More articles by this author Kazuyuki Numakura More articles by this author Hiroshi Tsuruta More articles by this author Atsushi Maeno More articles by this author Mitsuru Saito More articles by this author Takamitsu Inoue More articles by this author Norihiko Tsuchiya More articles by this author Hiroshi Nanjo More articles by this author Shigeru Satoh More articles by this author Tomonori Habuchi More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Abstract 2069: Stromal-epithelial crosstalk of Mig-6 has an important role for tumor suppression via progesterone in endometrial cancer

Abstract Endometrial cancer is the most common malignancy of the female genital tract. This disease is commonly caused by an imbalance of progesterone (P4) and estrogen (E2) action that E2 stimulates proliferation of uterine epithelial cells while P4 is inhibitory to estrogen-mediated proliferation of the epithelium. Endometrial hyperplasia is also associated with endometrial cancer, which is a proliferative process in epithelium by E2. Responsiveness of progesterone is required to treat endometrial cancer and preserve the fertility of patients. Furthermore, PR expression in the uteri of patients with endometrial cancer has been used as an indicator for a first-rate prognosis. However, more than 30% of patients do not respond to progesterone treatment as a result of progesterone resistance and the mechanism of progesterone resistance is still unknown. Thus, identifying the mechanism of progesterone in endometrial cancer is essential to improve the therapy of this disease. Mitogen-inducible gene 6 (Mig-6) is an important mediator of progesterone receptor (PR) 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. Interestingly, the hyperplasia exhibited by Sprr2fcre+ Mig-6f/f mice was prevented by P4 treatment for 1 week in morphological and histological analysis. Proliferation decreased in the glandular epithelium of Sprr2fcre+ Mig-6f/f mice by P4, and apoptotic signal was also reduced. The expressions of stromal PR and its target genes were induced in Sprr2fcre+ Mig-6f/f mice after P4 treatment, indicating that P4-induced stromal Mig-6 can prevent the hyperplasia via regulating steroid hormonal signaling. This study suggested that stromal-epithelial communication of Mig-6 is critical in tumor suppressor function via regulating steroid hormonal signaling by progesterone. (This work was supported by American Cancer Society Research Grant, RSG-12-084-01-TBG to J.W.J.) Citation Format: Tae Hoon Kim, Byung Gak Kim, Jung-Yoon Yoo, Jae Hee Lee, Diego H. Castrillon, Jae-Wook Jeong. Stromal-epithelial crosstalk of Mig-6 has an important role for tumor suppression via progesterone in endometrial cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2069. doi:10.1158/1538-7445.AM2015-2069

Steroid hormone intervenes in the endometrial tumorigenesis of pten ablation.

Background:Endometrial cancer, the most common gynecological cancer, is closely associated with endometrial hyperplasia, unopposed estrogen exposure, and genetic alterations. Phosphatase and tensin homologue (PTEN) is a tumor suppressor genes completely lost or mutated in >50% of primary endometrioid endometrial cancers. Estrogen-dependent endometrioid carcinoma is the most common type of endometrial cancer. Progesterone is a hormone that antagonizes the growth-promoting properties of estrogen in the uterus. Progestin is used as a conservative endocrine treatment of early endometrial cancer in order to preserve fertility as well as a palliative measure for advanced-stage patients. Progesterone therapy has been shown to be effective in preventing endometrial cancer as well as controlling growth of the endometrium. However, the effectiveness of progestin for women with endometrial cancer is less clear.Methods:In order to understand the effect of steroid hormone on endometrial cancer progression, we used a mouse endometrial cancer model with conditional loss of Pten in the mouse uterus (PRcre/+ Ptenf/f, Ptend/d). To assess the effect of steroid hormones, ovariectomized Ptenf/f and Ptend/d mice were treated with estrogen or progesterone over a period of three month.Results:Uterine weight gain was significantly decreased in ovariectomized PRcre/+ Ptenf/f mice compared to intact PRcre/+ Ptenf/f mice. Ovariectomized PRcre/+ Ptenf/f mice treated with P4 or vehicle also exhibited decreased uterine cancer size compared with intact PRcre/+ Ptenf/f mice. Proliferation of ovariectomized PRcre/+ Ptenf/f mice treated with P4 is highly decreased compared to other groups. The levels of stromal progesterone receptor were highly increased in ovariectomized PRcre/+ Ptenf/f mice treated with P4 which resulted in decreased epithelial proliferation.Conclusions:These results suggest that P4 treatment significantly reduces tumor mass but does not affect cancer progression in PRcre/+ Ptenf/f mice.

Uterine NK Cells Regulate Endometrial Bleeding in Women and Are Suppressed by the Progesterone Receptor Modulator Asoprisnil

Uterine NK cells (uNK) play a role in the regulation of placentation, but their functions in nonpregnant endometrium are not understood. We have previously reported suppression of endometrial bleeding and alteration of spiral artery morphology in women exposed to asoprisnil, a progesterone receptor modulator. We now compare global endometrial gene expression in asoprisnil-treated versus control women, and we demonstrate a statistically significant reduction of genes in the IL-15 pathway, known to play a key role in uNK development and function. Suppression of IL-15 by asoprisnil was also observed at mRNA level (p < 0.05), and immunostaining for NK cell marker CD56 revealed a striking reduction of uNK in asoprisnil-treated endometrium (p < 0.001). IL-15 levels in normal endometrium are progesterone-responsive. Progesterone receptor (PR) positive stromal cells transcribe both IL-15 and IL-15RA. Thus, the response of stromal cells to progesterone will be to increase IL-15 trans-presentation to uNK, supporting their expansion and differentiation. In asoprisnil-treated endometrium, there is a marked downregulation of stromal PR expression and virtual absence of uNK. These novel findings indicate that the IL-15 pathway provides a missing link in the complex interplay among endometrial stromal cells, uNK, and spiral arteries affecting physiologic and pathologic endometrial bleeding.

Progesterone Receptor Signaling in the Microenvironment of Endometrial Cancer Influences Its Response to Hormonal Therapy

Progesterone, an agonist for the progesterone receptor (PR), can be an efficacious and well-tolerated treatment in endometrial cancer. The clinical use of progesterone is limited because of the lack of biomarkers that predict hormone sensitivity. Despite its efficacy in cancer therapy, mechanisms and site of action for progesterone remain unknown. Using an in vivo endometrial cancer mouse model driven by clinically relevant genetic changes but dichotomous responses to hormonal therapy, we show that signaling through stromal PR is necessary and sufficient for progesterone antitumor effects. Endometrial cancers resulting from epithelial loss of PTEN (PTENKO) were hormone sensitive and had abundant expression of stromal PR. Stromal deletion of PR as a single genetic change in these tumors induced progesterone resistance indicating that paracrine signaling through the stroma is essential for the progesterone therapeutic effects. A hormone-refractory endometrial tumor with low levels of stromal PR developed when activation of KRAS was coupled with PTEN-loss (PTENKO/Kras). The innate progesterone resistance in PTENKO/Kras tumors stemmed from methylation of PR in the tumor microenvironment. Add-back of stromal PR expressed from a constitutively active promoter sensitized these tumors to progesterone therapy. Results show that signaling through stromal PR is sufficient for inducing hormone responsiveness. Our findings suggest that epigenetic derepression of stromal PR could be a potential therapeutic target for sensitizing hormone-refractory endometrial tumors to progesterone therapy. On the basis of these results, stromal expression of PR may emerge as a reliable biomarker in predicting response to hormonal therapy.

Abstract 4964: Signaling through the progesterone receptor in the tumor microenvironment regulates hormonal sensitivity in endometrial carcinoma.

Abstract Progesterone, an agonist for the progesterone receptor (PR), can be an efficacious and well tolerated oral treatment for subsets of women with endometrial cancer. Clinically, progesterone is under-utilized as reliable predictors of response are not available. Although progesterone has been used for decades in treatment of endometrial neoplasia, its mechanism and site of action remain unknown. Our study aims to determine how and through which tumor cell types does progesterone exert its anti-tumor effects. To address these questions we first established an in vivo endometrial cancer model based on the two most common genetic mutations seen in human endometrial carcinoma: cell autonomous loss of PTEN with or without activation of Kras. Importantly in this model we can genetically manipulate the tumor epithelium and stroma independently. Mouse endometrial tumors generated in this system closely resemble human disease. The progesterone hormone with or with out estrogen was administered to tumor bearing mice. When both hormones were co-administered to mice bearing PTEN null endometrial tumors complete resolution of the cancer was achieved. Abundant expression of PR was detected in the tumor stroma throughout this therapeutic time-course. When progesterone was administered without estrogen, PTEN-null tumors persisted and stromal expression of PR diminished. Conditional stromal-specific deletion of PR in PTEN-null tumors was sufficient to convert these hormone sensitive cancers to a progesterone resistant tumor despite estrogen and progesterone co-administration. These results suggest that stromal expression of PR is necessary for anti-tumor effects of progesterone and dual hormone administration is critical for achieving a therapeutic response. Cell-autonomous activation of K-ras is commonly detected in the context of PTEN loss and this genetic combination in our model resulted in a hormone refractory endometrial cancer. A significant reduction in stromal PR expression was found in the PTEN-null/Kras hormone refractory tumors compared to PTEN-null sensitive cancers. Loss of stromal PR in all cases was coupled with diminished phosphorylation of estrogen receptor α at serine 118. We demonstrate that anti-tumor effects of progesterone are exerted through stromal PR signaling. The loss of PR expression in the tumor microenvironment confers progesterone resistance; therefore pharmacologic restoration of stromal PR should be investigated as a therapeutic intervention in hormone refractory tumors. Regulation of PR in the tumor stroma may be modulated by estrogen signaling. Defining mechanisms of resistance and sensitivity to hormonal therapy will facilitate individualization and wider application of hormonal therapy in patients suffering from endometrial cancer. Citation Format: Deanna M. Janzen, Miguel A. Rosales, Daniel Y. Paik, Daniel A. Smith, Donghui Cheng, Owen N. Witte, Luisa Iruela-Arispe, Sanaz Memarzadeh. Signaling through the progesterone receptor in the tumor microenvironment regulates hormonal sensitivity in endometrial carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4964. doi:10.1158/1538-7445.AM2013-4964

Signal transducer and activator of transcription‐3 (Stat3) plays a critical role in implantationviaprogesterone receptor in uterus

Recent studies have shown that activation of the signal transducer and activator of transcription-3 (Stat3) is required for decidualization, interacting with progesterone receptor (PR) in uterus. Based on previous reports, we hypothesized that crosstalk between STAT3 and PR signaling is required for successful implantation. To identify the interaction between STAT3 and PR isoforms, we performed immunoprecipitation following transient cotransfection and found that STAT3 physically interacted with PR-A, which is known to be important for uterine development and function, but not with PR-B. To further investigate the role of Stat3 in uterine function, Stat3 was conditionally ablated only in the PR-positive cells (PR(cre/+) Stat3(f/f); Stat3(d/d)). Our studies revealed that ovarian function and uterine development of Stat3(d/d) mice were normal. However, Stat3(d/d) female mice were infertile due to defective embryo implantation. Unlike Stat3(f/f) mice, Stat3(d/d) mice exhibited an unclosed uterine lumen. Furthermore, uteri of Stat3(d/d) mice were unable to undergo a well-characterized hormonally induced decidual reaction. The expression of stromal PR was decreased during decidualization and preimplantation period in Stat3(d/d) mice, and PR target genes were significantly down-regulated after progesterone induction. Our results suggest that STAT3 and PR crosstalk is required for successful implantation in the mouse uterus.

The Reproductive Phenotype of Mice Null for Transcription Factor Krüppel-Like Factor 13 Suggests Compensatory Function of Family Member Krüppel-Like Factor 9 in the Peri-Implantation Uterus1

The ovarian hormones estrogen and progesterone promote uterine receptivity and successful pregnancy through their cognate receptors functioning in concert with context-dependent nuclear coregulators. Previously, we showed that the transcription factor Krüppel-like factor (KLF) 9 is a progesterone receptor (PGR) coactivator in the uterus and that mice null for Klf9 exhibit subfertility and reduced progesterone sensitivity. The highly related family member KLF13 displays increased expression in uteri of pregnant and nonpregnant Klf9 null mice and similarly regulates PGR-mediated transactivation in endometrial stromal cells. However, a uterine phenotype with loss of Klf13 has not been reported. In the present study, we demonstrate that Klf13 deficiency in mice did not compromise female fertility and pregnancy outcome. Klf13 null females had litter sizes, numbers of implanting embryos, uterine morphology, and ovarian steroid hormone production comparable to those of wild-type (WT) counterparts. Further, pregnant WT and Klf13 null females at Day Postcoitum (DPC) 3.5 had similar uterine Pgr, estrogen receptor, and Wnt-signaling component transcript levels. Nuclear levels of KLF9 were higher in Klf13 null than in WT uteri at DPC 3.5, albeit whole-tissue KLF9 protein and transcript levels did not differ between genotypes. The lack of a similar induction of nuclear KLF9 levels in uteri of virgin Klf13((-/-)) mice relative to WT uteri was associated with lower stromal PGR expression. In differentiating human endometrial stromal cells, coincident KLF9/KLF13 knockdown by small interfering RNA targeting reduced decidualization-associated PRL expression, whereas KLF9 and KLF13 knockdowns alone reduced transcript levels of WNT4 and BMP2, respectively. Results suggest that KLF9 and KLF13 functionally compensate in peri-implantation uterus for pregnancy success.

Epithelial progesterone receptor exhibits pleiotropic roles in uterine development and function

The ovarian steroid progesterone, acting through the progesterone receptor (PR), coordinates endometrial epithelial-stromal cell communication, which is critical for its development and function. PR expression in these cellular compartments is under tight temporal and endocrine control. Although ex vivo studies demonstrated the importance of stromal PR expression, they failed to show a role for epithelial PR in uterine function. Here, the in vivo role of PR in the uterine epithelium is defined using floxed PR (PR(f/f)) mice crossed to Wnt7a-Cre mice. Progesterone was unable to stimulate the expression of its epithelial target genes, including Ihh, in the Wnt7a-Cre(+)PR(f/-) mice. Analysis was conducted on Ihh to determine whether PR directly regulates epithelial gene transcription. ChIP-on-chip analysis identified PR binding sites in the 5'-flanking region of Ihh. Cotransfection of the proximal Ihh promoter with PR demonstrated that PR directly regulates Ihh transcription. Female Wnt7a-Cre(+)PR(f/-) mice are infertile due to defects in embryo attachment, stromal cell decidualization, and the inability to cease estrogen-induced epithelial cell proliferation. Finally, progesterone was unable to inhibit neonatal endometrial glandular development in Wnt7a-Cre(+)PR(f/-) mice. Thus, epithelial PR is necessary for the regulation of progesterone epithelial target gene expression, as well as uterine function and development.

Changes in glandular and stromal estrogen and progesterone receptor isoform expression in eutopic and ectopic endometrium following treatment with the levonorgestrel-releasing intrauterine system

Objectives The levonorgestrel (LNG) intrauterine system (LNG-IUS) has been shown to improve symptoms in women with minimal to moderate endometriosis. The precise mechanism for this is unknown. We hypothesized that this involves alteration in the expression of estrogen receptors (ER) and progesterone receptors (PR). Study design A prospective study of tissues obtained prospectively from 28 women with laparoscopically confirmed minimal to moderate endometriosis treated with LNG-IUS for 6 months. Endometrial and endometriotic biopsies obtained before and 6 months after treatment were processed and stained for ER-α, ER-β and PR expression by immunohistochemistry. Photographs were obtained and the receptors quantified. Results The mean (±SD) age of the 28 women was 31 ± 7.2 (range 18–42) years. Eight of them at initial biopsy were in the proliferative phase and 20 in the secretory phase. ER-α, ER-β and PR expression decreased significantly in the glandular ( P < 0.0001) and stromal ( P < 0.0001) compartments of the eutopic endometrium after treatment with LNG-IUS. Similarly, ER-α, ER-β and PR were significantly decreased in the stromal compartment of ectopic endometrium ( P < 0.0001), and significantly decreased in the ectopic glands of ER-α ( P < 0.0001), ER-β ( P = 0.0002) and PR ( P = 0.0064) expression. Conclusion The ameliorative effect of LNG-IUS on the symptoms of minimal to moderate endometriosis is likely modulated through a decrease in the expression of glandular and stromal ER-α, ER-β and PR in the ectopic endometrium.

Conditional Ablation of the Progesterone Receptor Specifically in the Uterine Epithelium Demonstrates Its Necessary Role in the Regulation of Uterine Function.

Uterine progesterone receptor (PR), expressed in both the epithelium and stroma, mediates epithelial-stromal crosstalk during embryo implantation and pregnancy. Ex vivo tissue reconstitution studies have pointed to stromal PR as being critical for the regulation of uterine epithelial gene expression (i.e., Indian hedgehog (Ihh)) and inhibition of mitogenic estrogen (E2) action whereas the role of epithelial PR has been largely unexplored. Here, we investigated the vivo role of epithelial PR during pregnancy and in the regulation of epithelial gene expression using compartment-specific ablation of PR. Using the Wnt7a-Cre mouse model, PR was ablated specifically in the uterine epithelium. This ablation rendered female mice infertile, demonstrating that epithelial PR is critical for female fertility. We examined uterine function by assessing the ability of these mice to undergo the decidual response. The epithelial PR conditional knockout mice failed to display a decidual response indicating that, despite the presence of PR in the stroma, decidualization is unable to occur without epithelial PR. We next wanted to determine if epithelial PR may regulate the expression of progesterone (P4)-target genes. Epithelial PR is critical for P4-induction of epithelial P4-target genes (Ihh, Areg, Gata2, Cyp26a1), but not stromal P4-target genes (Il13ra2). Transfection analysis revealed that epithelial PR can transactivate Ihh gene expression in Hec1a cells further confirming its critical role in P4-target gene expression. Therefore, epithelial PR plays a critical role in epithelial P4-target gene expression which differs from previous observations using tissue reconstitution experiments. In the uterus, P4 inhibits E2 actions such as uterine weight gain, epithelial proliferation, and E2-target gene expression. Normal P4-inhibition of estrogen-induced weight gain was observed in these mice. However, examination of P4-inhibition of specific E2-target genes demonstrated that epithelial PR plays a gene-specific role in P4-inhibition exhibiting inhibition of Ltf and Clca3 expression, but not Lif expression. We are currently studying its potential role in P4-inhibition of E2-induced epithelial proliferation. In summary, using an in vivo mouse model, we have shown that epithelial PR is necessary for female fertility as a mediator of decidualization, P4-target gene expression, and the P4-inhibition of E2 action. This work was supported by NIH Grant RO1CA077530 (to J.P.L.) and R01HD042311 (to F.J.D.). (platform)

Levonorgestrel-releasing intrauterine system (LNG-IUS) as an effective treatment option for endometrial hyperplasia: a 15-year follow-up study

The levonorgestrel-releasing intrauterine system may represent an effective treatment option in >85% of endometrial hyperplasia cases, but histologic regression during and/or at the end of treatment does not assure stable recovery. We recommend periodic endometrial samplings for at least the first 2 years of follow-up and long-term clinical surveillance thereafter.