Decreased epithelial progesterone receptor A at the window of receptivity is required for preparation of the endometrium for embryo attachment.

The precise timing of progesterone signaling through its cognate receptor, the progesterone receptor (PGR), is critical for the establishment and maintenance of pregnancy. Loss of PGR expression in the murine uterine epithelium during the preimplantation period is a marker for uterine receptivity and embryo attachment. We hypothesized that the decrease in progesterone receptor A (PGRA) expression is necessary for successful embryo implantation. To test this hypothesis, a mouse model constitutively expressing PGRA (mPgrALsL/+) was generated. Expression of PGRA in all uterine compartments (Pgrcre) or uterine epithelium (Wnt7acre) resulted in infertility with defects in embryo attachment and stromal decidualization. Expression of critical PGRA target genes, indian hedgehog, and amphiregulin (Areg), was maintained through the window of receptivity while the estrogen receptor target gene, the leukemia inhibitory factor (Lif), a key regulator of embryo receptivity, was decreased. Transcriptomic and cistromic analyses of the mouse uterus at day 4.5 of pregnancy identified an altered group of genes regulating molecular transport in the control of fluid and ion levels within the uterine interstitial space. Additionally, LIF and its cognate receptor, the leukemia inhibitory factor receptor (LIFR), exhibited PGR-binding events in regions upstream of the transcriptional start sites, suggesting PGRA is inhibiting transcription at these loci. Therefore, downregulation of the PGRA isoform at the window of receptivity is necessary for the attenuation of hedgehog signaling, transcriptional activation of LIF signaling, and modulation of solutes and fluid, producing a receptive environment for the attaching embryo.

IL6/JAK1/STAT3 Signaling Blockade in Endometrial Cancer Affects the ALDHhi/CD126+ Stem-like Component and Reduces Tumor Burden.

Cancer stem-like cells (CSC) may be critical to maintain the malignant behavior of solid and hematopoietic cancers. Recently, patients with endometrial cancer whose tumors expressed high levels of aldehyde dehydrogenase (ALDH), a detoxifying enzyme characteristic of many progenitor and stem cells, exhibited a relative reduction in survival compared with patients with low levels of ALDH. Given evidence of its role as a CSC marker, we hypothesized that high level of ALDH activity (ALDH(hi)) in a tumor might positively correlate with the presence of stem- and progenitor-like tumor cells in this disease setting. In support of this hypothesis, ALDH could be used to enrich for CSC in endometrial cancer cell lines and primary tumors, as illustrated by the increased tumor-initiating capacity of ALDH(hi) cells in immunodeficient mice. ALDH(hi) cells also exhibited greater clonogenic and organoid-forming capacity compared with ALDH(lo) cells. Notably, the number of ALDH(hi) cells in tumor cell lines and primary tumors inversely correlated with differentiation grade. Expression analysis revealed upregulation of IL6 receptor subunits and signal transducers CD126 and GP130 in ALDH(hi) endometrial cancer cells. Accordingly, targeted inhibition of the IL6 receptor and its downstream effectors JAK1 and STAT3 dramatically reduced tumor cell growth. Overall, our results provide a preclinical rationale to target IL6 or its effector functions as a novel therapeutic option in endometrial cancer.

Progesterone receptor membrane component 1 deficiency attenuates growth while promoting chemosensitivity of human endometrial xenograft tumors.

Endometrial cancer is the leading gynecologic cancer in women in the United States with 52,630 women predicted to be diagnosed with the disease in 2014. The objective of this study was to determine if progesterone (P4) receptor membrane component 1 (PGRMC1) influenced endometrial cancer cell viability in response to chemotherapy in vitro and in vivo. A lentiviral-based shRNA knockdown approach was used to generate stable PGRMC1-intact and PGRMC1-deplete Ishikawa endometrial cancer cell lines that also lacked expression of the classical progesterone receptor (PGR). Progesterone treatment inhibited mitosis of PGRMC1-intact, but not PGRMC1-deplete cells, suggesting that PGRMC1 mediates the anti-mitotic actions of P4. To test the hypothesis that PGRMC1 attenuates chemotherapy-induced apoptosis, PGRMC1-intact and PGRMC1-deplete cells were treated in vitro with vehicle, P4 (1 µM), doxorubicin (Dox, 2 µg/ml), or P4 + Dox for 48 h. Doxorubicin treatment of PGRMC1-intact cells resulted in a significant increase in cell death; however, co-treatment with P4 significantly attenuated Dox-induced cell death. This response to P4 was lost in PGRMC1-deplete cells. To extend these observations in vivo, a xenograft model was employed where PGRMC1-intact and PGRMC1-deplete endometrial tumors were generated following subcutaneous and intraperitoneal inoculation of immunocompromised NOD/SCID and nude mice, respectively. Tumors derived from PGRMC1-deplete cells grew slower than tumors from PGRMC1-intact cells. Mice harboring endometrial tumors were then given three treatments of vehicle (1:1 cremophor EL: ethanol + 0.9% saline) or chemotherapy [Paclitaxel (15 mg/kg, i.p.) followed after an interval of 30 minutes by CARBOplatin (50 mg/kg)] at five day intervals. In response to chemotherapy, tumor volume decreased approximately four-fold more in PGRMC1-deplete tumors when compared with PGRMC1-intact control tumors, suggesting that PGRMC1 promotes tumor cell viability during chemotherapeutic stress. In sum, these in vitro and in vivo findings demonstrate that PGRMC1 plays a prominent role in the growth and chemoresistance of human endometrial tumors.

A mouse model for endometrioid ovarian cancer arising from the distal oviduct.

Ovarian cancer is the deadliest gynecological malignancy in Western countries. Early detection, however, is hampered by the fact that the origin of ovarian cancer remains unclear. Knowing that in a high percentage of endometrioid ovarian cancers Wnt/ß-catenin signaling is activated, and in view of the hypothesis that ovarian cancer may originate from the distal oviduct, we studied mice in which Wnt/ß-catenin signaling was activated in Müllerian duct-derived tissues. Conditional adenomatous polyposis coli (Apc) knockout mice were used to study the activation of Wnt/ß-catenin signaling in Müllerian duct-derived organs. These Pgr(Cre/+);Apc(ex15lox/lox) mice (n = 44) were sacrificed at 10, 20, 40 and 80 weeks and uterus, oviduct, ovaries and surrounding fat tissues were assessed using immunohistochemistry. Using nuclear ß-catenin staining, Wnt/ß-catenin signaling activation was confirmed in the entire epithelium of the adult Müllerian duct (fimbriae, oviduct and endometrium), but was absent in ovarian surface epithelium cells (OSEs). Besides endometrial hyperplasia, in 87.2% of mice intraepithelial lesions of the distal oviduct were found, whereas OSEs remained unaffected. In addition, 62.5% of mice developed tumors in the distal and fimbrial part of the oviduct. In the ovaries, mainly at young age, in 16.3% of mice, simple epithelial cysts were noted, which developed further into endometrioid ovarian tumors, resembling human endometrioid ovarian cancer (27.9% of mice). Next to this, locoregional growth in the utero-ovarian ligament was also shown. Here, for the first time, mutations (activation of Wnt/ß-catenin) in the distal oviduct result in precursor lesions that develop into ovarian tumors, resembling human endometrioid ovarian cancer.

Alterations in Wnt-ß-catenin and Pten signalling play distinct roles in endometrial cancer initiation and progression.

Endometrioid endometrial cancer arises through a gradual series of histological changes, each accompanied by specific alterations in gene expression and activity. Activation of the Wnt-ß-catenin pathway and loss of PTEN activity are frequently observed in endometrial cancers. However, the specific roles played by alterations in these pathways in the initiation and progression of endometrial cancer are currently unclear. Here, we investigated the effects of loss of Pten and Apc gene function in the mouse endometrium by employing tissue-specific and inducible mutant alleles, followed by immunohistochemical (IHC) and loss of heterozygosity (LOH) analysis of their corresponding cancerous lesions. Loss of the Apc function in the endometrium leads to cytoplasmic and nuclear ß-catenin accumulation in association with uterine hyperplasia and squamous cell metaplasia, but without malignant transformation. Loss of Pten function also resulted in squamous metaplasia but, in contrast to loss of Apc function, it initiates endometrial cancer. On the other hand, loss of Apc function in the endometrium accelerates Pten-driven endometrial tumourigenesis. Analysis of compound heterozygous mice confirmed that somatic loss of the wild-type Pten allele represents the rate-limiting initiation step in endometrial cancer. Simultaneous loss of Pten and Apc resulted in endometrial cancer characterized by earlier onset and a more aggressive malignant behaviour. These observations are indicative of the synergistic action between the Wnt-ß-catenin and Pten signalling pathways in endometrial cancer onset and progression.

Identification of quiescent, stem-like cells in the distal female reproductive tract.

In fertile women, the endometrium undergoes regular cycles of tissue build-up and regression. It is likely that uterine stem cells are involved in this remarkable turn over. The main goal of our current investigations was to identify slow-cycling (quiescent) endometrial stem cells by means of a pulse-chase approach to selectively earmark, prospectively isolate, and characterize label-retaining cells (LRCs). To this aim, transgenic mice expressing histone2B-GFP (H2B-GFP) in a Tet-inducible fashion were administered doxycycline (pulse) which was thereafter withdrawn from the drinking water (chase). Over time, dividing cells progressively loose GFP signal whereas infrequently dividing cells retain H2B-GFP expression. We evaluated H2B-GFP retaining cells at different chase time points and identified long-term (LT; >12 weeks) LRCs. The LT-LRCs are negative for estrogen receptor-α and express low levels of progesterone receptors. LRCs sorted by FACS are able to form spheroids capable of self-renewal and differentiation. Upon serum stimulation spheroid cells are induced to differentiate and form glandular structures which express markers of mature mullerian epithelial cells. Overall, the results indicate that quiescent cells located in the distal oviduct have stem-like properties and can differentiate into distinct cell lineages specific of endometrium, proximal and distal oviduct. Future lineage-tracing studies will elucidate the role played by these cells in homeostasis, tissue injury and cancer of the female reproductive tract in the mouse and eventually in man.

Progesterone inhibits epithelial-to-mesenchymal transition in endometrial cancer.

BACKGROUND: Every year approximately 74,000 women die of endometrial cancer, mainly due to recurrent or metastatic disease. The presence of tumor infiltrating lymphocytes (TILs) as well as progesterone receptor (PR) positivity has been correlated with improved prognosis. This study describes two mechanisms by which progesterone inhibits metastatic spread of endometrial cancer: by stimulating T-cell infiltration and by inhibiting epithelial-to-mesenchymal cell transition (EMT). METHODOLOGY AND PRINCIPAL FINDINGS: Paraffin sections from patients with (n = 9) or without (n = 9) progressive endometrial cancer (recurrent or metastatic disease) were assessed for the presence of CD4+ (helper), CD8+ (cytotoxic) and Foxp3+ (regulatory) T-lymphocytes and PR expression. Progressive disease was observed to be associated with significant loss of TILs and loss of PR expression. Frozen tumor samples, used for genome-wide expression analysis, showed significant regulation of pathways involved in immunesurveillance, EMT and metastasis. For a number of genes, such as CXCL14, DKK1, DKK4, PEG10 and WIF1, quantitive RT-PCR was performed to verify up- or downregulation in progressive disease. To corroborate the role of progesterone in regulating invasion, Ishikawa (IK) endometrial cancer cell lines stably transfected with PRA (IKPRA), PRB (IKPRB) and PRA+PRB (IKPRAB) were cultured in presence/absence of progesterone (MPA) and used for genome-wide expression analysis, Boyden- and wound healing migration assays, and IHC for known EMT markers. IKPRB and IKPRAB cell lines showed MPA induced inhibition of migration and loss of the mesenchymal marker vimentin at the invasive front of the wound healing assay. Furthermore, pathway analysis of significantly MPA regulated genes showed significant down regulation of important pathways involved in EMT, immunesuppression and metastasis: such as IL6-, TGF-ß and Wnt/ß-catenin signaling. CONCLUSION: Intact progesterone signaling in non-progressive endometrial cancer seems to be an important factor stimulating immunosurveilance and inhibiting transition from an epithelial to a more mesenchymal, more invasive phenotype.

An autoimmune phenotype in vulvar lichen sclerosus and lichen planus: a Th1 response and high levels of microRNA-155.

Vulvar lichen sclerosus and lichen planus are T-cell-mediated chronic skin disorders. Although autoimmunity has been suggested, the exact pathogenesis of these disorders is still unknown. Therefore, the aim of the current study was to investigate the molecular and immunological mechanisms critical to the pathogenesis of vulvar lichen sclerosus and lichen planus. By using gene expression profiling and real-time RT-PCR experiments, we demonstrated a significantly increased expression of the pro-inflammatory cytokines (IFNγ, CXCR3, CXCL9, CXCL10, CXCL11, CCR5, CCL4, and CCL5) specific for a Th1 IFNγ-induced immune response. In addition, BIC/microRNA-155 (miR-155)--a microRNA involved in regulation of the immune response--was significantly upregulated in lichen sclerosus and lichen planus (9.5- and 17.7-fold change, respectively). Immunohistochemistry showed a significant T-cell response, with pronounced dermal infiltrates of CD4(+), CD8(+), and FOXP3(+) cells. In conclusion, these data demonstrate an autoimmune phenotype in vulvar lichen sclerosus and lichen planus, characterized by increased levels of Th1-specific cytokines, a dense T-cell infiltrate, and enhanced BIC/miR-155 expression.

Interaction between sex hormones and WNT/ß-catenin signal transduction in endometrial physiology and disease.

Wnt/ß-catenin signalling plays a rate-limiting role in early development of many different organs in a broad spectrum of organisms. In the developing Müllerian duct, Wnt/ß-catenin signalling is important for initiation, outgrowth, patterning and differentiation into vagina, cervix, uterus and oviducts. In adult life, sex hormones modulate Wnt/ß-catenin signalling in the endometrium to maintain the monthly balance between estrogen-induced proliferation and progesterone-induced differentiation, and enhanced Wnt/ß-catenin signalling seems to be involved in endometrial carcinogenesis. However, early in pregnancy enhanced Wnt/ß-catenin signalling is prerequisite for proper implantation and invasion of trophoblast cells into endometrium and myometrium thus helping to form a placenta. Overall, it seems that tight control of Wnt/ß-catenin signalling in time and space is important for initiation, development and normal function of the female reproductive tract. However, if Wnt/ß-catenin signalling is not kept in check, it easily seems to initiate or contribute to development of a number of uterine disorders.

Different DNA damage and cell cycle checkpoint control in low- and high-risk human papillomavirus infections of the vulva.

Human papillomavirus (HPV) infections may result in benign hyperplasia, caused by low-risk HPV types, or (pre)malignant lesions caused by high-risk HPV types. The molecular basis of this difference in malignant potential is not completely understood. Here, we performed gene profiling of different HPV infected vulvar tissues (condylomata acuminata (n = 5), usual type vulvar intraepithelial neoplasia (uVIN) (n = 9)) and control samples (n = 14) using Affymetrix Human U133A plus 2 GeneChips. Data were analyzed using OmniViz®, Partek® and Ingenuity® Software. Results were validated by real-time RT-PCR and immunostaining. Although similarities were observed between gene expression profiles of low- and high-risk HPV infected tissues (e.g., absence of estrogen receptor in condylomata and uVIN), high-risk HPV infected tissues showed more proliferation and displayed more DNA damage than tissues infected with low-risk HPV. These observations were confirmed by differential regulation of cell cycle checkpoints and by increased expression of DNA damage-biomarkers p53 and γH2AX. Furthermore, FANCA, FANCD2, BRCA1 and RAD51, key players in the DNA damage response, were significantly upregulated (p < 0.05). In addition, we compared our results with publicly available gene expression profiles of various other HPV-induced cancers (vulva, cervix and head-and-neck). This showed p16(INK4a) was the most significant marker to detect a high-risk HPV infection, but no other markers could be found. In conclusion, this study provides insight into the molecular basis of low- and high-risk HPV infections and indicates two main pathways (cell cycle and DNA damage response) that are much stronger affected by high-risk HPV as compared to low-risk HPV.

AMG 479, a novel IGF-1-R antibody, inhibits endometrial cancer cell proliferation through disruption of the PI3K/Akt and MAPK pathways.

Our goal was to evaluate the therapeutic potential of a novel antibody to the insulin growth factor-1 receptor (IGF-1-R; AMG 479) in endometrial cancer cells. The endometrial cancer cell lines, ECC-1/PRAB72 and RL-95-2, were used. Treatment with AMG 479 (0.02-200 nmol/L) resulted in inhibition of cell proliferation at 72 to 120 hours. Insulin growth factor-1 (0.15-7.5 nmol/L) stimulated growth in both cell lines (range of 15%-42%, P = .0025-.0445), which could be blocked by pretreatment with AMG 479 (mean of 29% for ECC-1/PRAB72, P = .006-.007; mean of 36% for RL-95-2, P = .0002-.0045). AMG 479 suppressed IGF-1-R kinase activity in a dose-dependent manner. Cells treated with AMG 479 underwent either G1 (ECC-1/PRAB72) or G2 (RL-95-2) arrest. AMG 479 decreased human telomerase reverse transcriptase (hTERT) mRNA expression in both endometrial cancer cell lines. Treatment with AMG 479 rapidly blocked IGF-1-induced phosphorylation of IFG-1-R, Akt, and p44/42. Thus, manipulation of the IGF-1-R pathway may serve as a promising therapeutic strategy for the treatment of endometrial cancer.

Progesterone receptor-B induction of BIRC3 protects endometrial cancer cells from AP1-59-mediated apoptosis.

Progesterone is a growth inhibitory hormone in the endometrium. While progestins can be used for the treatment of well-differentiated endometrial cancers, resistance to progestin therapy occurs for reasons that remain unclear. We have previously demonstrated that progesterone receptors (PR) A and B differentially regulate apoptosis in response to overexpression of the forkhead transcription factor, FOXO1. In this study, we further examined the PR-isoform-dependent cellular response to the AKT pathway. Treatment of PRA and PRB-expressing Ishikawa cells (PRA14, PRB23), with an AKT inhibitor API-59CJ-OMe (API-59) promoted apoptosis in the presence and absence of the ligand, R5020 preferentially in PRA14 cells. Upon PR knockdown using small interfering RNA, an increase in apoptosis was observed in PRB23 cells treated with API-59 with or without R5020 while there was no influence in PRA14 cells. Using an apoptosis-focused real-time PCR array, genes regulated by API-59 and R5020 were identified both common and unique to PRA14 and PRB23 cells. BIRC3 was identified as the only gene regulated by R5020 which occurred only in PRB cells. Knockdown of BIRC3 in PRB23 cells promoted a decrease in cell viability in response to API-59 + R5020. Furthermore, the important role of inhibitors of apoptosis (IAPs) in the PRB23 cells to promote cell survival was demonstrated using an antagonist to IAPs, a second mitochondria-derived activator of caspase (Smac also known as DIABLO) mimetic. Treatment of PRB23 cells with Smac mimetic increased apoptosis in response to API-59 + R5020. In summary, our findings indicate a mechanism by which PRB can promote cell survival in the setting of high AKT activity in endometrial cancer cells.

Loss of APC function in mesenchymal cells surrounding the Müllerian duct leads to myometrial defects in adult mice.

The WNT signal transduction pathway plays a rate limiting role in early development of many different organs. To study the functional consequences of constitutive activation of the canonical WNT pathway in the developing uterus, we generated a novel mouse model where loss of the tumor suppressor gene Apc was induced. A mouse model was generated and evaluated where Amhr2(Cre/+) driven loss of Apc exon 15 was induced. The Apc recombination was detected mainly in the myometrial layer of the adult uterus. A significant loss of muscle fibers in myometrium was apparent, though with very few muscle cells earmarked by nuclear ß-catenin. The finding was confirmed in the Pgr(Cre/+);Apc(15lox/15lox) mouse model. Loss of APC function in mesenchymal cells surrounding the fetal Müllerian ducts results in severe defects in the myometrial layers of the uterus in adult mice, suggesting that the WNT signaling pathway plays important roles in maintaining myometrial integrity.

Treatment of vulvar intraepithelial neoplasia with topical imiquimod: seven years median follow-up of a randomized clinical trial.

OBJECTIVE: Recently we reported on the efficacy of imiquimod for treating vulvar intraepithelial neoplasia (VIN) in a placebo-controlled, double-blinded randomized clinical trial (RCT). Four weeks after treatment, a complete response was observed in 35% of patients and a partial response in 46%. All complete responders remained disease-free at 12 months follow-up. In the current investigations, we assessed long-term follow-up at least 5 years after the initial RCT. METHODS: Twenty-four of 26 imiquimod-treated patients who had participated in the initial RCT were seen for follow-up. Primary endpoint was durability of clinical response to imiquimod assessed by naked eye vulvar examination and histology. Long-term clinical response was correlated to lesion size before start of the initial RCT. Secondary endpoints were mental health, global quality of life, body image and sexual function in relation with long-term clinical response. RESULTS: Median follow-up period was 7.2 years (range 5.6-8.3 years). VIN recurred in one of nine complete responders. Of the initial partial responders, two became disease-free after additional imiquimod treatment. In the other partial responders, VIN recurred at least once after the initial RCT. In long-term complete responders, lesion size at study entry was smaller and these patients had a significantly better global quality of life at follow-up than patients with residual disease and/or recurrence after imiquimod treatment. CONCLUSIONS: In case of a complete response, imiquimod is effective in the long-term. Furthermore, patients with a long-term complete response had a significantly better global quality of life than patients who recurred after imiquimod treatment.

Nonsteroidal anti-inflammatory drugs do not interfere with imiquimod treatment for usual type vulvar intraepithelial neoplasia.

Imiquimod has been shown to be an effective treatment for usual type vulvar intraepithelial neoplasia (uVIN). Since local inflammation and burning are common side effects, patients often use nonsteroidal anti-inflammatory drugs (NSAIDs). Our study investigated whether NSAID-use, which has been documented to inhibit the cell-mediated immune response, interferes with the outcome of imiquimod treatment. Monocyte-derived dendritic cells (moDCs) and Langerhans cells (moLCs) were cultured in the presence of NSAIDs. The expression of relevant surface markers (CD80, CD86, CD40, HLA-DR, CCR6 and CCR7), stimulatory function, and cytokine production were evaluated. Furthermore, we analyzed in uVIN patients whether frequent NSAID-use had an effect on the clinical response and on immunocompetent cell counts before and after imiquimod treatment. Although an effect was observed on the expression of moDC and moLC maturation markers, NSAIDs did not affect the ability of moDCs and moLCs to stimulate allogeneic T-cell proliferation, or the production of cytokines in an allogeneic T-cell stimulation assay. In agreement with this, in uVIN patients treated with imiquimod, no interference of frequent NSAID-use with clinical outcome was observed. However, we did notice that high CD1a(+) and CD207(+) cell counts in frequent NSAID-users before treatment seemed to predict a favourable response to imiquimod treatment. Our data indicate that NSAID-use does not seem to interfere with moDC and moLC function and does not interfere with immunomodulatory properties of imiquimod in uVIN patients. Therefore, NSAIDs can safely be used to reduce imiquimod side effects in uVIN patients during treatment.

Premalignant epithelial disorders of the vulva: squamous vulvar intraepithelial neoplasia, vulvar Paget's disease and melanoma in situ.

No standard screening programs exist to detect vulvar carcinoma or its precursor lesions, and therefore gynecologists, dermatologists and other healthcare providers in this field should be aware of the clinical features, behavior and management of the different existing premalignant vulvar lesions, squamous vulvar intraepithelial neoplasia (VIN), vulvar Paget's disease and melanoma in situ. In 2004, a new classification for squamous VIN was introduced by the International Society for the Study of Vulvar Disease, subdividing squamous VIN into the HPV-related usual type, and into differentiated type, which is associated with lichen sclerosus. This review describes the relevant aspects of squamous VIN, vulvar Paget's disease and melanoma in situ, its epidemiological characteristics, diagnosis, management and malignant potential.

Microsomal epoxide hydrolase expression in the endometrial uterine corpus is regulated by progesterone during the menstrual cycle.

We have shown previously that high expression levels of microsomal epoxide hydrolase (mEH) correlate with a poor prognosis of breast cancer patients receiving tamoxifen, suggesting that enhanced mEH expression could lead to antiestrogen resistance (Fritz et al. in J Clin Oncol 19:3-9, 2001). Thus, the purpose of this study was to gain insights into the role of mEH in hormone-responsive tissues. We analyzed biopsy samples of the endometrium by immunohistochemical staining, pointing to a regulation of mEH during the menstrual cycle: during the first half mEH expression was low, increased during the second half and reached highest levels during pregnancy. Additionally, the progesterone receptor (PR) positive human endometrial cell lines IKPRAB-36 (estrogene receptor alpha [ERalpha] negative) and ECC1-PRAB72 (ERalpha positive) were chosen to further investigate the hormonal regulation of mEH expression. Western Blot and quantitative RT-PCR analysis revealed an increase of mEH expression after treatment with medroxy-progesterone 17-acetate (MPA) in the ERalpha containing ECC1-PRAB72 cells. In contrast our results suggest that MPA had no influence on the mEH protein level in the ERalpha- IKPRAB-36 cells. In conclusion, mEH expression is regulated by progesterone in the presence of both PRs and ERalpha.

Wnt/Β-catenin and sex hormone signaling in endometrial homeostasis and cancer.

A delicate balance between estrogen and progestagen signaling underlies proper functioning of the female reproductive tract and, in particular, the monthly re- and degenerative phases characteristic of the menstrual cycle. Here, we propose that the canonical Wnt/ß-catenin signaling pathway may underlie this finely tuned hormonal equilibrium in endometrial homeostasis and, upon its constitutive activation, lead to neoplastic transformation of the endometrium. During the menstrual cycle, estradiol will enhance Wnt/ß-catenin signaling in the proliferative phase, while progesterone inhibits Wnt/ß-catenin signaling, thus restraining estrogens' proliferative actions, during the secretory phase. In case of enhanced or unopposed estrogen signaling, constitutive activation of Wnt/ß-catenin signaling will trigger endometrial hyperplasia, which may develop further into endometrial cancer.

Imiquimod-induced clearance of HPV is associated with normalization of immune cell counts in usual type vulvar intraepithelial neoplasia.

Recently, we reported on the efficacy of imiquimod for treatment of usual type vulvar intraepithelial neoplasia (uVIN). A histologic regression of uVIN to normal tissue was observed in 58% of patients. As success of treatment is related to clearance of high-risk human papilloma virus (HPV), the aim of our study was to assess differences in immune cell counts and in the expression of p16(INK4a) in VIN tissue before and after imiquimod treatment, in relation to HPV clearance and clinical response. Vulvar tissue samples taken prior to imiquimod treatment and 4 weeks after treatment were tested for the presence of HPV. Previously determined immune cell counts (CD1a, CD207, CD208, CD123/CD11c, CD94, CD4, CD8 and CD25/HLA-DR) in epidermis and dermis of 25 VIN patients and 19 healthy controls were completed with the counts for CD14 and CD68. The expression of p16(INK4a) was investigated by immunohistochemistry in 15 patients. Before imiquimod treatment, both HPV cleared and HPV noncleared patients showed mainly in the dermis significantly upregulated immune cell counts compared to healthy controls. However, in patients that cleared HPV and showed histologic regression already 4 weeks after imiquimod treatment, immune cell counts and p16(INK4a) expression were normalized. In conclusion, our data indicate that imiquimod-induced clearance of HPV results in normalization of counts for certain immune cells and is strongly correlated with histologic regression of the disease.

Progesterone inhibition of Wnt/beta-catenin signaling in normal endometrium and endometrial cancer.

PURPOSE: Wnt signaling regulates the fine balance between stemness and differentiation. Here, the role of Wnt signaling to maintain the balance between estrogen-induced proliferation and progesterone-induced differentiation during the menstrual cycle, as well as during the induction of hyperplasia and carcinogenesis of the endometrium, was investigated. EXPERIMENTAL DESIGN: Endometrial gene expression profiles from estradiol (E(2)) and E(2) + medroxyprogesterone acetate-treated postmenopausal patients were combined with profiles obtained during the menstrual cycle (PubMed; GEO DataSets). Ishikawa cells were transfected with progesterone receptors and Wnt inhibitors dickkopf homologue 1 (DKK1) and forkhead box O1 (FOXO1), measuring Wnt activation. Expression of DKK1 and FOXO1 was inhibited by use of sequence-specific short hairpins. Furthermore, patient samples (hormone-treated endometria, hyperplasia, and endometrial cancer) were stained for Wnt activation using nuclear beta-catenin and CD44. RESULTS: In vivo, targets and components of the Wnt signaling pathway (among them DKK1 and FOXO1) are regulated by E(2) and progesterone. In Wnt-activated Ishikawa cells, progesterone inhibits Wnt signaling by induction of DKK1 and FOXO1. Furthermore, using siRNA-mediated knockdown of both DKK1 and FOXO1, progesterone inhibition of Wnt signaling was partly circumvented. Subsequently, immunohistochemical analysis of the Wnt target gene CD44 showed that progesterone acted as an inhibitor of Wnt signaling in hyperplasia and in well-differentiated endometrial cancer. CONCLUSION: Progesterone induction of DKK1 and FOXO1 results in inhibition of Wnt signaling in the human endometrium. This Wnt inhibitory effect of progesterone is likely to play a rate-limiting role in the maintenance of endometrial homeostasis and, on its loss, in tumor onset and progression toward malignancy.