Anti-angiogenic mechanisms and serotonergic dysfunction in the Rgs2 knockout model for the study of psycho-obstetric risk

Psychiatric and obstetric diseases are growing threats to public health and share high rates of co-morbidity. G protein-coupled receptor signaling (e.g., vasopressin, serotonin) may be a convergent psycho-obstetric risk mechanism. Regulator of G Protein Signaling 2 (RGS2) mutations increase risk for both the gestational disease preeclampsia and for depression. We previously found preeclampsia-like, anti-angiogenic obstetric phenotypes with reduced placental Rgs2 expression in mice. Here, we extend this to test whether conserved cerebrovascular and serotonergic mechanisms are also associated with risk for neurobiological phenotypes in the Rgs2 KO mouse. Rgs2 KO exhibited anxiety-, depression-, and hedonic-like behaviors. Cortical vascular density and vessel length decreased in Rgs2 KO; cortical and white matter thickness and cell densities were unchanged. In Rgs2 KO, serotonergic gene expression was sex-specifically changed (e.g., cortical Htr2a, Maoa increased in females but all serotonin targets unchanged or decreased in males); redox-related expression increased in paraventricular nucleus and aorta; and angiogenic gene expression was changed in male but not female cortex. Whole-cell recordings from dorsal raphe serotonin neurons revealed altered 5-HT1A receptor-dependent inhibitory postsynaptic currents (5-HT1A-IPSCs) in female but not male KO neurons. Additionally, serotonin transporter blockade by the SSRI sertraline increased the amplitude and time-to-peak of 5-HT1A-IPSCs in KO neurons to a greater extent than in WT neurons in females only. These results demonstrate behavioral, cerebrovascular, and sertraline hypersensitivity phenotypes in Rgs2 KOs, some of which are sex-specific. Disruptions may be driven by vascular and cell stress mechanisms linking the shared pathogenesis of psychiatric and obstetric disease to reveal future targets.

Global expression analysis of endometrial cancer cells in response to progesterone identifies new therapeutic targets

Progesterone prevents development of endometrial cancers through its receptor (PR) although the molecular mechanisms have yet to be fully characterized. In this study, we performed a global analysis of gene regulation by progesterone using human endometrial cancer cells that expressed PR endogenously or exogenously. We found progesterone strongly inhibits multiple components of the platelet derived growth factor receptor (PDGFR), Janus kinase (JAK), signal transducer and activator of transcription (STAT) pathway through PR. The PDGFR/JAK/STAT pathway signals to control numerous downstream targets including AP-1 transcription factors Fos and Jun. Treatment with inhibitors of the PDGFR/JAK/STAT pathway significantly blocked proliferation in multiple novel patient-derived organoid models of endometrial cancer, and activation of this pathway was found to be a poor prognostic signal for the survival of patients with endometrial cancer from The Cancer Genome Atlas. Our study identifies this pathway as central to the growth-limiting effects of progesterone in endometrial cancer and suggests that inhibitors of PDGFR/JAK/STAT should be considered for future therapeutic interventions.

Microbial Communities in Gynecological Cancers and Their Association with Tumor Somatic Variation

There are strong correlations between the microbiome and human disease, including cancer. However, very little is known about potential mechanisms associated with malignant transformation in microbiome-associated gynecological cancer, except for HPV-induced cervical cancer. Our hypothesis is that differences in bacterial communities in upper genital tract epithelium may lead to selection of specific genomic variation at the cellular level of these tissues that may predispose to their malignant transformation. We first assessed differences in the taxonomic composition of microbial communities and genomic variation between gynecologic cancers and normal samples. Then, we performed a correlation analysis to assess whether differences in microbial communities selected for specific single nucleotide variation (SNV) between normal and gynecological cancers. We validated these results in independent datasets. This is a retrospective nested case-control study that used clinical and genomic information to perform all analyses. Our present study confirms a changing landscape in microbial communities as we progress into the upper genital tract, with more diversity in lower levels of the tract. Some of the different genomic variations between cancer and controls strongly correlated with the changing microbial communities. Pathway analyses including these correlated genes may help understand the basis for how changing bacterial landscapes may lead to these cancers. However, one of the most important implications of our findings is the possibility of cancer prevention in women at risk by detecting altered bacterial communities in the upper genital tract epithelium.

Particles and Prejudice: Nanomedicine Approaches to Reducing Health Disparities in Endometrial Cancer

Endometrial cancer is the most common gynecological malignancy worldwide and unfortunately has a much higher mortality rate in Black women compared with White women. Many potential factors contribute to these mortality rates, including the underlying effects of systemic and interpersonal racism. Furthermore, other trends in medicine have potential links to these rates including participation in clinical trials, hormone therapy, and pre-existing health conditions. Addressing the high incidence and disparate mortality rates in endometrial cancer requires novel methods, such as nanoparticle-based therapeutics. These therapeutics have been growing in increasing prevalence in pre-clinical development and have far-reaching implications in cancer therapy. The rigor of pre-clinical studies is enhanced by the likeness of the model to the human body. In systems for 3D cell culture, for example, the extracellular matrix mimics the tumor more closely. The increasing emphasis on precision medicine can be applied to cancer using nanoparticle-based methods and applied to pre-clinical models by using patient-derived model data. This review highlights the intersections of nanomedicine, precision medicine, and racial disparities within endometrial cancer and provides insights into reducing health disparities using recent scientific advances on the nanoscale.

FGFR2 mutations promote endometrial cancer progression through dual engagement of EGFR and Notch signalling pathways

BACKGROUND

Mutations in the receptor tyrosine kinase gene fibroblast growth factor receptor 2 (FGFR2) occur at a high frequency in endometrial cancer (EC) and have been linked to advanced and recurrent disease. However, little is known about how these mutations drive carcinogenesis.

METHODS

Differential transcriptomic analysis and two-step quantitative real-time PCR (qRT-PCR) assays were applied to identify genes differentially expressed in two cohorts of EC patients carrying mutations in the FGFR2 gene as well as in EC cells harbouring mutations in the FGFR2. Candidate genes and target signalling pathways were investigated by qRT-PCR assays, immunohistochemistry and bioinformatics analysis. The functional roles of differently regulated genes were analysed using in vitro and in vivo experiments, including 3D-orthotypic co-culture systems, cell proliferation and migration protocols, as well as colony and focus formation assays together with murine xenograft tumour models. The molecular mechanisms were examined using CRISPR/Cas9-based loss-of-function and pharmacological approaches as well as luciferase reporter techniques, cell-based ectodomain shedding assays and bioinformatics analysis.

RESULTS

We show that common FGFR2 mutations significantly enhance the sensitivity to FGF7-mediated activation of a disintegrin and metalloprotease (ADAM)17 and subsequent transactivation of the epidermal growth factor receptor (EGFR). We further show that FGFR2 mutants trigger the activation of ADAM10-mediated Notch signalling in an ADAM17-dependent manner, highlighting for the first time an intimate cooperation between EGFR and Notch pathways in EC. Differential transcriptomic analysis in EC cells in a cohort of patients carrying mutations in the FGFR2 gene identified a strong association between FGFR2 mutations and increased expression of members of the Notch pathway and ErbB receptor family. Notably, FGFR2 mutants are not constitutively active but require FGF7 stimulation to reprogram Notch and EGFR pathway components, resulting in ADAM17-dependent oncogenic growth.

CONCLUSIONS

These findings highlight a pivotal role of ADAM17 in the pathogenesis of EC and provide a compelling rationale for targeting ADAM17 protease activity in FGFR2-driven cancers.

Placenta-specific protein 1 (PLAC1) expression is significantly down-regulated in preeclampsia via a hypoxia-mediated mechanism

OBJECTIVE

Examine a mechanism of PLAC1 regulation and its potential role in preeclampsia (PE).

MATERIALS AND METHODS

Placental tissue samples and detailed clinical information were obtained through the University of Iowa Maternal Fetal Tissue Bank (IRB# 200910784) from gestational and maternal age-matched control (n = 17) and PE affected pregnancies (n = 12). PLAC1 and PLAC1 promoter-specific expression was measured using quantitative polymerase chain reaction (qPCR) and differences were assessed via the standard ΔΔCt method. In addition, the role of hypoxia in PLAC1 transcription was investigated through the exposure of HTR8/SVneo human trophoblast cells to the hypoxia mimic dimethyloxaloylglycine (DMOG).

RESULTS

PLAC1 expression is seen to be 8.9-fold lower in human placentas affected by preeclampsia in comparison with controls (p < .05). Further, this decrease is paralleled by a significantly lower expression of the P2 or proximal PLAC1 promoter (p < .05). Expression of mediator complex subunit 1 (MED1), a known hypoxia-sensitive transcription coactivator and PLAC1 effector, is significantly correlated with PLAC 1 expression (r2 = 0.607, p < .001). These data suggest that PLAC1 expression is significantly down-regulated in preeclampsia at least in part via a MED1 hypoxia-mediated mechanism.

CONCLUSIONS

We confirm that PLAC1 transcription is suppressed in the placentae of women affected by preeclampsia. We further demonstrate that this suppression is driven through the P2 or proximal PLAC1 promoter. This demonstration led to the identification of the MED1-TRAP cofactor complex as the hypoxia-sensitive driver.

Using Genomic Variation to Distinguish Ovarian High-Grade Serous Carcinoma from Benign Fallopian Tubes

The preoperative diagnosis of pelvic masses has been elusive to date. Methods for characterization such as CA-125 have had limited specificity. We hypothesize that genomic variation can be used to create prediction models which accurately distinguish high grade serous ovarian cancer (HGSC) from benign tissue.

METHODS

In this retrospective, pilot study, we extracted DNA and RNA from HGSC specimens and from benign fallopian tubes. Then, we performed whole exome sequencing and RNA sequencing, and identified single nucleotide variants (SNV), copy number variants (CNV) and structural variants (SV). We used these variants to create prediction models to distinguish cancer from benign tissue. The models were then validated in independent datasets and with a machine learning platform.

RESULTS

The prediction model with SNV had an AUC of 1.00 (95% CI 1.00-1.00). The models with CNV and SV had AUC of 0.87 and 0.73, respectively. Validated models also had excellent performances.

CONCLUSIONS

Genomic variation of HGSC can be used to create prediction models which accurately discriminate cancer from benign tissue. Further refining of these models (early-stage samples, other tumor types) has the potential to lead to detection of ovarian cancer in blood with cell free DNA, even in early stage.

TP53 Sequencing and p53 Immunohistochemistry Predict Outcomes When Bevacizumab Is Added to Frontline Chemotherapy in Endometrial Cancer: An NRG Oncology/Gynecologic Oncology Group Study

PURPOSE

The status of p53 in a tumor can be inferred by next-generation sequencing (NGS) or by immunohistochemistry (IHC). We examined the association between p53 IHC and sequence and whether p53 IHC alone, or integrated with TP53 NGS, predicts the outcome.

METHODS

From GOG-86P, a randomized phase II study of chemotherapy combined with either bevacizumab or temsirolimus in advanced endometrial cancer, 213 cases had p53 protein expression data measured by IHC and TP53 NGS data. An analysis was designed to integrate p53 expression by IHC with the presence or absence of a TP53 mutation. These variables were further correlated with progression-free survival (PFS) and overall survival (OS) in the chemotherapy plus bevacizumab arms versus the chemotherapy plus temsirolimus arm.

RESULTS

In the analysis of p53 IHC, the most striking treatment effect favoring bevacizumab was in cases where p53 was overexpressed (PFS hazard ratio [HR]: 0.46, 95% CI, 0.26 to 0.88; OS HR: 0.31, 95% CI, 0.16 to 0.62). On integrated analysis, patients with TP53 missense mutations and p53 protein overexpression had a similar treatment effect on PFS (HR: 0.41, 95% CI, 0.22 to 0.83) and OS (HR: 0.28, 95% CI, 0.14 to 0.59) favoring bevacizumab plus chemotherapy relative to temsirolimus plus chemotherapy. Concordance between TP53 NGS and p53 IHC was 88%. Concordance was 92% when cases with TP53 mutations and POLE mutations or mismatch repair deficiency were removed.

CONCLUSION

IHC for p53 alone or when integrated with sequencing for TP53 identifies a specific, high-risk tumor genotype/phenotype for which bevacizumab is particularly beneficial in improving outcomes when combined with chemotherapy.

Association between plasma leptin and cesarean section after induction of labor: a case control study

Background

Obesity in pregnancy is common, with more than 50% of pregnant women being overweight or obese. Obesity has been identified as an independent predictor of dysfunctional labor and is associated with increased risk of failed induction of labor resulting in cesarean section. Leptin, an adipokine, is secreted from adipose tissue under the control of the obesity gene. Concentrations of leptin increase with increasing percent body fat due to elevated leptin production from the adipose tissue of obese individuals. Interestingly, the placenta is also a major source of leptin production during pregnancy. Leptin has regulatory effects on neuronal tissue, vascular smooth muscle, and nonvascular smooth muscle systems. It has also been demonstrated that leptin has an inhibitory effect on myometrial contractility with both intensity and frequency of contractions decreased. These findings suggest that leptin may play an important role in dysfunctional labor and be associated with the outcome of induction of labor at term. Our aim is to determine whether maternal plasma leptin concentration is indicative of the outcome of induction of labor at term. We hypothesize that elevated maternal plasma leptin levels are associated with a failed term induction of labor resulting in a cesarean delivery.

Methods

In this case-control study, leptin was measured in 3rd trimester plasma samples. To analyze labor outcomes, 174 women were selected based on having undergone an induction of labor (IOL), (115 women with successful IOL and 59 women with a failed IOL). Plasma samples and clinical information were obtained from the UI Maternal Fetal Tissue Bank (IRB# 200910784). Maternal plasma leptin and total protein concentrations were measured using commercially available assays. Bivariate analyses and logistic regression models were constructed using regression identified clinically significant confounding variables. All variables were tested at significance level of 0.05.

Results

Women with failed IOL had higher maternal plasma leptin values (0.5 vs 0.3 pg, P = 0.01). These women were more likely to have obesity (mean BMI 32 vs 27 kg/m², P = 0.0002) as well as require multiple induction methods (93% vs 73%, p = 0.008). Logistic regression showed Bishop score (OR 1.5, p < 0.001), BMI (OR 0.92, P < 0.001), preeclampsia (OR 0.12, P = 0.010), use of multiple methods of induction (OR 0.22, P = 0.008) and leptin (OR 0.42, P = 0.017) were significantly associated with IOL outcome. Specifically, after controlling for BMI, Bishop Score, and preeclampsia, leptin was still predictive of a failed IOL with an odds ratio of 0.47 (P = 0.046). Finally, using leptin as a predictor for fetal outcomes, leptin was also associated with of fetal intolerance of labor, with an odds ratio of 2.3 (P = 0.027). This association remained but failed to meet statistical significance when controlling for successful (IOL) (OR 1.5, P = 0.50).

Conclusions

Maternal plasma leptin may be a useful tool for determining which women are likely to have a failed induction of labor and for counseling women about undertaking an induction of labor versus proceeding with cesarean delivery.

The Synthetic Curcumin Analog HO-3867 Rescues Suppression of PLAC1 Expression in Ovarian Cancer Cells

Elevated expression of placenta-specific protein 1 (PLAC1) is associated with the increased proliferation and invasiveness of a variety of human cancers, including ovarian cancer. Recent studies have shown that the tumor suppressor p53 directly suppresses PLAC1 transcription. However, mutations in p53 lead to the loss of PLAC1 transcriptional suppression. Small molecules that structurally convert mutant p53 proteins to wild-type conformations are emerging. Our objective was to determine whether the restoration of the wild-type function of mutated p53 could rescue PLAC1 transcriptional suppression in tumors harboring certain TP53 mutations. Ovarian cancer cells OVCAR3 and ES-2, both harboring TP53 missense mutations, were treated with the p53 reactivator HO-3867. Treatment with HO-3867 successfully rescued PLAC1 transcriptional suppression. In addition, cell proliferation was inhibited and cell death through apoptosis was increased in both cell lines. We conclude that the use of HO-3867 as an adjuvant to conventional therapeutics in ovarian cancers harboring TP53 missense mutations could improve patient outcomes. Validation of this conclusion must, however, come from an appropriately designed clinical trial.

Successful Patient-Derived Organoid Culture of Gynecologic Cancers for Disease Modeling and Drug Sensitivity Testing

Developing reliable experimental models that can predict clinical response before treating the patient is a high priority in gynecologic cancer research, especially in advanced or recurrent endometrial and ovarian cancers. Patient-derived organoids (PDOs) represent such an opportunity. Herein, we describe our successful creation of 43 tumor organoid cultures and nine adjacent normal tissue organoid cultures derived from patients with endometrial or ovarian cancer. From an initial set of 45 tumor tissues and seven ascites fluid samples harvested at surgery, 83% grew as organoids. Drug sensitivity testing and organoid cell viability assays were performed in 19 PDOs, a process that was accomplished within seven days of obtaining the initial surgical tumor sample. Sufficient numbers of cells were obtained to facilitate testing of the most commonly used agents for ovarian and endometrial cancer. The models reflected a range of sensitivity to platinum-containing chemotherapy as well as other relevant agents. One PDO from a patient treated prior to surgery with neoadjuvant trastuzumab successfully predicted the patient's postoperative chemotherapy and trastuzumab resistance. In addition, the PDO drug sensitivity assay identified alternative treatment options that are currently used in the second-line setting. Our findings suggest that PDOs could be used as a preclinical platform for personalized cancer therapy for gynecologic cancer patients.

Identification of Novel Fusion Transcripts in High Grade Serous Ovarian Cancer

Fusion genes are structural chromosomal rearrangements resulting in the exchange of DNA sequences between genes. This results in the formation of a new combined gene. They have been implicated in carcinogenesis in a number of different cancers, though they have been understudied in high grade serous ovarian cancer. This study used high throughput tools to compare the transcriptome of high grade serous ovarian cancer and normal fallopian tubes in the interest of identifying unique fusion transcripts within each group. Indeed, we found that there were significantly more fusion transcripts in the cancer samples relative to the normal fallopian tubes. Following this, the role of fusion transcripts in chemo-response and overall survival was investigated. This led to the identification of fusion transcripts significantly associated with overall survival. Validation was performed with different analytical platforms and different algorithms to find fusion transcripts.

Creation and validation of models to predict response to primary treatment in serous ovarian cancer

Nearly a third of patients with high-grade serous ovarian cancer (HGSC) do not respond to initial therapy and have an overall poor prognosis. However, there are no validated tools that accurately predict which patients will not respond. Our objective is to create and validate accurate models of prediction for treatment response in HGSC. This is a retrospective case–control study that integrates comprehensive clinical and genomic data from 88 patients with HGSC from a single institution. Responders were those patients with a progression-free survival of at least 6 months after treatment. Only patients with complete clinical information and frozen specimen at surgery were included. Gene, miRNA, exon, and long non-coding RNA (lncRNA) expression, gene copy number, genomic variation, and fusion-gene determination were extracted from RNA-sequencing data. DNA methylation analysis was performed. Initial selection of informative variables was performed with univariate ANOVA with cross-validation. Significant variables (p < 0.05) were included in multivariate lasso regression prediction models. Initial models included only one variable. Variables were then combined to create complex models. Model performance was measured with area under the curve (AUC). Validation of all models was performed using TCGA HGSC database. By integrating clinical and genomic variables, we achieved prediction performances of over 95% in AUC. Most performances in the validation set did not differ from the training set. Models with DNA methylation or lncRNA underperformed in the validation set. Integrating comprehensive clinical and genomic data from patients with HGSC results in accurate and robust prediction models of treatment response.

Prediction of Epithelial Ovarian Cancer Outcomes With Integration of Genomic Data

Some of the patients with epithelial ovarian cancer will not respond to initial therapy. These patients have a poor prognosis. Our aim was to identify patients with a worse prognosis by integrating clinical, pathologic, and genomic data. Using publicly available genomic data and integrating it with clinical data, we significantly improved the prediction of patients with worse surgical outcomes and those who do not respond to initial chemotherapy. We further improved these models with more precise data collection and better understanding of the genetic background of the studied population. Better prediction will lead to better patient classification and opportunities for individualized treatment.

Abstract PR006: Correlation of immunohistochemistry with TP53 sequence and clinical outcomes in GOG-086P

Introduction: GOG-086P was one of the first attempts to combine molecular inhibitors such as bevacizumab or temsirolimus with chemotherapy in patients with advanced endometrial cancer. An exploratory analysis of this study indicates that bevacizumab combined with chemotherapy is superior to temsirolimus plus chemotherapy in patients with TP53 mutated tumors as determined by next generation sequencing. The functional status of p53 in a tumor can be inferred by sequence analysis and/or by immunohistochemistry (IHC). In this next study of the GOG-086P cohort, we sought to determine whether p53 IHC alone or integrated with TP53 sequencing was similarly predictive of outcome and whether IHC was predictive of the sequence analysis. Methods: A total of 349 patients were enrolled on GOG-086P. Two hundred and forty-three patients have TP53 sequence data, and 213 have p53 protein expression data measured by IHC. Tumor histology and sequence data were correlated with p53 IHC categorizing each case as p53 negative or null, wild type (WT) or over-expressed (OE), and these variables were further correlated with progression-free survival (PFS) and overall survival (OS) in the chemotherapy + bevacizumab arms versus the chemotherapy + temsirolimus arm. Results: The majority of patients (118) had tumors with WT p53 protein expression by IHC and non-mutated or WT TP53 sequence, with expected concordance between IHC and sequence analysis. However, there were five discordant cases with OE p53 protein in the absence of a TP53 mutation. Fourteen patients had null IHC protein expression and a concordant TP53 sequence mutation expected to result in the total loss of protein. Four cases that were p53 null by IHC had a discordant WT TP53 sequence. Seventeen patients had tumors with a missense TP53 mutation but had WT p53 protein expression by IHC, reflecting a potential discordance between sequencing and IHC versus a missense mutation that did not result in loss of protein function. Six of these 17 discordant cases may be explained by co-mutations in TP53 and POLE or microsatellite instability where p53 proteins, though mutated, function more like WT. Reassuringly and as expected, high concordance was found in the 55 cases that had OE protein by IHC and a missense mutation in TP53. On integrated analysis, a TP53 mutation with p53 protein OE was associated with significantly lower hazard ratio for PFS (HR=0.41; 95% CI 0.22-0.83) and OS (HR=0.28; 95% CI 0.14-0.59), i.e., longer PFS and OS, for patients receiving bevacizumab + chemotherapy relative to temsirolimus + chemotherapy. Conclusions: Mutations in TP53, which are common in patients with advanced endometrial cancer, represent a developing platform upon which to design personalized treatment regimens. We demonstrate that IHC is often but not always predictive of the TP53 sequence. However, most cases with over-expressed p53 protein by IHC had a mutation in TP53, and bevacizumab + chemotherapy prolonged PFS and OS in such patients.

Citation Format: Kristina W. Thiel, Eric J. Devor, Virginia Filiaci, Douglas A. Levine, Fanny Dao, Narciso Olvera, David Mutch, Carol Aghajanian, Kimberly K. Leslie. Correlation of immunohistochemistry with TP53 sequence and clinical outcomes in GOG-086P [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 PR006.

Abstract PO039: Combined histone deacetylase and proteasome inhibition in patient-derived endometrial cancer organoid models promotes massive cell death

Patient-derived organoids (PDOs) are a promising model for personalized cancer treatment. Accumulating evidence indicates that PDOs can predict clinical outcomes in patients. A handful studies in several cancer types have established that PDOs can recapitulate both histological and genomic features of the lesion from which they were derived. Additionally, PDOs can grow with high efficiency in a short time, enabling prediction of responsiveness to chemotherapy and development of more targeted therapies for patients. Our long-term goal is to create a PDO biorepository comprising all major histopathological subtypes of endometrial cancer, perform drug screening on these PDOs, and identify novel single agent and combinatorial regimens to advance into clinical trials. Herein we describe progress to date on generation of endometrial PDOs and drug screening to identify potential therapeutic options. First, we created PDO cultures from seven patients with different histological subtypes of endometrial cancer, including early stage/grade endometrioid adenocarcinoma and high-grade serous carcinoma. Next, we exposed each PDO to a panel of 23 chemotherapeutic agents and targeted drugs. Surprisingly, despite a divergent response to standard chemotherapy (platinum and taxane compounds), all PDOs showed high responsiveness to the combination of a histone deacetylase (HDAC) inhibitor and a proteasome inhibitor. Specifically, we achieved nearly complete cell killing within 72 hrs of exposure of organoid cultures to HDAC and proteasome inhibitors, with concentrations in the low nanomolar range. Similar results were achieved with different proteasome inhibitors (bortezomib and ixazomib) and HDAC inhibitors (romidepsin and belinostat). At present, these classes of agents have primarily been studied in multiple myeloma, though multiple clinical trials of combined proteasome and HDAC inhibitor therapy are active in advanced solid tumors and lymphomas. HDAC inhibitors maintain the acetylation of histones and thereby increase the expression of genes associated with apoptosis and cell cycle arrest. Proteasome inhibitors prevent proteasomal degradation, leading to upregulation of proapoptotic protein expression, cell cycle arrest, and ER stress, downregulation of angiogenesis and the pro-inflammatory protein NF-κB, and ROS generation. Mechanistically, HDAC inhibitors and proteasome inhibitors promote dual proteasome and aggresome blockage and induce apoptosis due to the accumulation of misfolded proteins. Our findings of profound tumor cell death in multiple different PDOs serve as the foundation for a future clinical trial using the HDAC inhibitor ixazomib and proteasome inhibitor romidepsin in advanced and recurrent endometrial cancers as well as high-grade serous ovarian cancer, which shares histologic and molecular features. Concomitantly, we are investigating the in vitro and in vivo effects of the combination on the induction of apoptosis and endometrial tumor regression.

Citation Format: Jianling Bi, Kristina W. Thiel, Eric J. Devor, Andreea M. Newtson, Yuping Zhang, Kimberly K. Leslie. Combined histone deacetylase and proteasome inhibition in patient-derived endometrial cancer organoid models promotes massive cell death [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 PO039.

Abstract PO046: Anti-angiogenic tyrosine kinase inhibitor cediranib is superior to bevacizumab in endometrial cancer due to differential effects on cell cycle regulation

Angiogenesis plays a crucial role in tumor development and metastasis, and many cancer cells upregulate vascular endothelial growth factor-A (VEGF-A) expression to promote angiogenesis. Several clinical trials of anti-angiogenic agents have been conducted in advanced and recurrent endometrial cancer, but only bevacizumab and cediranib have demonstrated activity as single agents. Bevacizumab is a monoclonal antibody against VEGF-A, whereas cediranib is a small molecule angiokinase inhibitor.

However, subsequent studies of bevacizumab+chemotherapy failed to improve outcomes compared to chemotherapy alone. We recently demonstrated that chemotherapy plus nintedanib, another angiokinase inhibitor, promotes catastrophic cell death in a xenograft model of endometrial cancer (Ebeid, et al., Nat Nanotech 2019). This effect was specific to cells with loss of function, i.e., null mutations in TP53. Here we compared the efficacy of cediranib vs. bevacizumab in p53-null gynecologic cancer models and determined the mechanism for differential sensitivity. We first performed a phosphoproteomic array of 875 phosphoproteins to define the signaling changes related to bevacizumab vs. cediranib in two p53-null cell gynecologic cancer cell lines. Several signaling events were similar between bevacizumab and cediranib, including phosphorylation of IGF1R, Abl, p70S6K and proteins in the ERK/MAPK and Wnt signaling pathways. We next tested the impact of the anti- angiogenic agents on cell viability using cancer cell lines and over 20 patient-derived organoid cultures of endometrial or ovarian cancer. Neither bevacizumab nor cediranib alone had a notable effect on cell viability, even at 1-10 µM concentrations. By contrast, cediranib but not bevacizumab promoted marked cell death when combined with chemotherapy. This effect was most pronounced in p53-null models.

Cell cycle analysis demonstrated an accumulation in mitosis after treatment with cediranib+chemotherapy, consistent with abrogation of the G2/M checkpoint and subsequent mitotic catastrophe. Molecular analysis of key controllers of the G2/M cell cycle checkpoint confirmed its abrogation. Unexpectedly, the endometrial cancer cell lines were unresponsive to stimulation with VEGF-A, the target of bevacizumab. This was confirmed by the lack of ERK phosphorylation, a downstream signaling event expected after VEGF-A treatment, and was potentially caused low expression of VEGFR1 and 2. Based on these data, we conclude that an anti-angiogenic tyrosine kinase inhibitor such as cediranib has the potential to be superior to bevacizumab in combination with chemotherapy. We hypothesize that the mechanism relates to cediranib inhibition of the tumor vasculature as well as its ability to optimize the impact of chemotherapeutic agents during the cell cycle. Future clinical studies should test this hypothesis by studying the combination of standard chemotherapy with cediranib in advanced and recurrent endometrial cancer.

Citation Format: Jianling Bi, Andreea M. Newtson, Eric J. Devor, Yuping Zhang, Kristina W. Thiel, Kimberly K. Leslie. Anti-angiogenic tyrosine kinase inhibitor cediranib is superior to bevacizumab in endometrial cancer due to differential effects on cell cycle regulation [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 PO046.

Abstract PO013: SNP rs1982 in the 3’UTR of placenta-specific protein 1 (PLAC1) is associated with endometrial cancer survival

Placenta-specific protein 1 (PLAC1) is a small (212aa) secreted protein normally only expressed on the apical surfaces of syncytiotrophoblasts. However, over the past two decades we and other investigators have shown that human cancers and, in particular, cancers of the human reproductive tract, induce PLAC1 expression. In gynecologic cancers, PLAC1 expression has been shown to be associated with risk, histology and TP53 mutation status. A previously unassessed informative SNP rs1982 (A&gt;C) lies in the 3’ untranslated region of the PLAC1 gene. We have begun to explore the utility of this SNP by genotyping a panel of 75 endometrial cancers. The panel is composed of 29 endometrial adenocarcinomas, 10 papillary serous adenocarcinomas, 9 mixed Mullerian tumors, 6 mixed histologies, 2 tumors identified as displaying complex atypia and 1 neuroendocrine tumor. High molecular weight genomic DNA was extracted from these tumors and SNP genotypes determined by directly sequencing a 312bp PCR amplicon generated by the primers:

rs1982for: GAGGATTGGTCTCTTCACACAG; rs1982rev: ACAATGTCTGGCCCATACTAAA

SNP genotypes were then evaluated against a variety of clinical variables including age, BMI, tobacco use, Charlson Index, co-morbidities, stage, grade, myometrial invasion, recurrence, and death by cancer using both univariate and multivariate logistic regression. Progression-free and overall survival were assessed by Cox Proportional Hazard ratio. Results show that CC homozygotes have increased progression-free and overall survival though neither reached statistical significance. However, several clinical variables were statistically associated with different rs1982 genotypes. Charlson co-morbidity Index was positively associated with presence of the wild-type A allele (OR = 1.61; 1.06 - 2.69; p&lt;0.05), while death from disease was negatively associated (OR = 0.15; 0.03 – 0.64; p&lt;0.02). These differences hold when accounting for other co-variates in the multivariate analysis. These data support further exploration of this SNP in gynecologic cancers.

Citation Format: Eric J. Devor, Jesus Gonzalez-Bosquet, Kimberly K. Leslie. SNP rs1982 in the 3’UTR of placenta-specific protein 1 (PLAC1) is associated with endometrial cancer survival [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 PO013.

Genomic characterization of five commonly used endometrial cancer cell lines

Recently, the compilation of massive amounts of genetic and genomic information on a wide variety of human cancer types, collectively known as The Cancer Genome Atlas (TCGA), has revealed a wealth of descriptive classification schemes both within and between different types and sources of cancer. In endometrial cancer, TCGA analyses have produced a post hoc scheme composed of four clusters: DNA polymerase ε catalytic subunit A (POLE) ultra‑mutated (cluster 1), microsatellite instability (MSI) hypermutated (cluster 2), copy‑number low (endometrioid, cluster 3) and copy‑number high (serous‑like, cluster 4). Given that cultured cells are the pre‑clinical platform of cancer research, it was questioned how representative endometrial cancer cultured cell lines are in the context of TCGA‑driven classification scheme. To address this issue in endometrial cancer cell lines, the present study investigated five commonly used cell lines: Ishikawa, ECC‑1, Hec50co, KLE And RL95‑2. The histology, mutation profile, MutL homolog 1 promoter methylation, copy‑number variation, homologous recombination repair and microsatellite instability in each of these cell lines was assessed. The result of this characterization was that none of the cell lines fits neatly into any one of TCGA classes but are still useful models for groups of endometrial tumors. Furthermore, the contention that the ECC‑1 cell line is actually Ishikawa was addressed using additional data. It was confirmed that ECC‑1 cells likely no longer exist as ECC‑1 but that they are not exactly Ishikawa either. For this reason, ECC‑1 cells are suggested to be used in vitro but with this caveat in mind. Finally, we compiled a database of 127 endometrial cancer cell lines, including the five reported on here. The wide range of variation found in these cell lines highlights the need to further characterize these cells to select models that are more representative of the various histological and genomic aspects of endometrial cancer.

Detargeting Lentiviral-Mediated CFTR Expression in Airway Basal Cells Using miR-106b

Lentiviral-mediated integration of a CFTR transgene cassette into airway basal cells is a strategy being considered for cystic fibrosis (CF) cell-based therapies. However, CFTR expression is highly regulated in differentiated airway cell types and a subset of intermediate basal cells destined to differentiate. Since basal stem cells typically do not express CFTR, suppressing the CFTR expression from the lentiviral vector in airway basal cells may be beneficial for maintaining their proliferative capacity and multipotency. We identified miR-106b as highly expressed in proliferating airway basal cells and extinguished in differentiated columnar cells. Herein, we developed lentiviral vectors with the miR-106b-target sequence (miRT) to both study miR-106b regulation during basal cell differentiation and detarget CFTR expression in basal cells. Given that miR-106b is expressed in the 293T cells used for viral production, obstacles of viral genome integrity and titers were overcome by creating a 293T-B2 cell line that inducibly expresses the RNAi suppressor B2 protein from flock house virus. While miR-106b vectors effectively detargeted reporter gene expression in proliferating basal cells and following differentiation in the air-liquid interface and organoid cultures, the CFTR-miRT vector produced significantly less CFTR-mediated current than the non-miR-targeted CFTR vector following transduction and differentiation of CF basal cells. These findings suggest that miR-106b is expressed in certain airway cell types that contribute to the majority of CFTR anion transport in airway epithelium.

Loss of progesterone receptor through epigenetic regulation is associated with poor prognosis in solid tumors

BACKGROUND

Hormonal therapy using progestins, acting through the progesterone receptor (PR), is a well-established method to treat uterine endometrial hyperplasia and carcinoma. Recent population studies indicate that progestin exposure significantly reduces the incidence of ovarian, pancreatic and lung cancers in addition to endometrial cancer in women. This unexpected differentiating function of progestin in organs outside of the reproductive system led us to hypothesize that progestins/PR are protective against cancer development and progression in many tumor types.

METHODS

The Cancer Genome Atlas, Oncomine and Prognostic Databases were searched to determine the relative expression of PR in tumors from multiple sites, and clinical outcomes linked to PR expression were determined. In addition, mRNA and protein expression were evaluated using real-time PCR and Western blotting. Chromatin immunoprecipitation (ChIP) assay was performed to understand the PR downregulation mechanisms in tumor cells and patient samples. Methylation-specific PCR was conducted to survey the PR methylation status. The Student's t-test were performed to determine significance. Flow cytometry was used to quantify apoptotic cells.

RESULTS

Low PR expression levels were consistently linked to less favorable clinical outcomes in endometrial, pancreatic, ovarian and non-small cell lung cancers. Clinical specimens and cell lines from these cancers demonstrate low levels of PR, and we now report that the mechanism for loss of PR is mediated through epigenetic repression. However, PR silencing can be overcome with epigenetic modulators. Histone deacetylase inhibitor (LBH589) and hypomethylating agent (5-aza-decitabine) restored functional PR expression at both the mRNA and protein levels and promoted marked cell death through induction of apoptosis in the presence of progesterone.

CONCLUSIONS

Our studies support the possibility that progestin therapy in combination with epigenetic modulators, a concept we term "molecularly enhanced progestin therapy", is an approach worthy of study for malignancies originating from tissues outside of the reproductive tract.

Reduced mRNA Expression of RGS2 (Regulator of G Protein Signaling-2) in the Placenta Is Associated With Human Preeclampsia and Sufficient to Cause Features of the Disorder in Mice

Cascade-specific termination of G protein signaling is catalyzed by the RGS (regulator of G protein signaling) family members, including RGS2. Angiotensin, vasopressin, and endothelin are implicated in preeclampsia, and RGS2 is known to inhibit G protein cascades activated by these hormones. Mutations in RGS2 are associated with human hypertension and increased risk of developing preeclampsia and its sequelae. RGS family members are known to influence maternal vascular function, but the role of RGS2 within the placenta has not been explored. Here, we hypothesized that reduced expression of RGS2 within the placenta represents a risk factor for the development of preeclampsia. Although cAMP/CREB signaling was enriched in placentas from human pregnancies affected by preeclampsia compared with clinically matched controls and RGS2 is known to be a CREB-responsive gene, RGS2 mRNA was reduced in placentas from pregnancies affected by preeclampsia. Experimentally reducing Rgs2 expression within the feto-placental unit was sufficient to induce preeclampsia-like phenotypes in pregnant wild-type C57BL/6J mice. Stimulation of RGS2 transcription within immortalized human HTR8/SVneo trophoblasts by cAMP/CREB signaling was discovered to be dependent on the activity of histone deacetylase activity, and more specifically, HDAC9 (histone deacetylase-9), and HDAC9 expression was reduced in placentas from human pregnancies affected by preeclampsia. We conclude that reduced expression of RGS2 within the placenta may mechanistically contribute to preeclampsia. More generally, this work identifies RGS2 as an HDAC9-dependent CREB-responsive gene, which may contribute to reduced RGS2 expression in placenta during preeclampsia.

Abstract P3039: Altered Maternal and Fetal Vasopressin Receptors in Response to Hypertensive Stress in Pregnancy

Children born to women with hypertensive disorders in pregnancy have an elevated risk of developing hypertensive disorders later in life. The mechanisms for this fetal programming are unclear. Because vasopressin (AVP) is a hormone that functions to regulate blood pressure and volume homeostasis, we hypothesized that differences in expression of vasopressin receptors (AVPRs) and related genes are also altered in children born from preeclampsia-affected pregnancies. We measured the expression of receptors AVPR1a, AVPR1b, AVPR2, OXTR, and CUL5 as well as LNPEP, the major aminopeptidase that cleaves AVP. Expression in umbilical cord blood cells and maternal peripheral blood cells from women with 1) no hypertensive disorders in pregnancy (control subjects) (N=20) 2) pregnant women with chronic hypertension (N=20) and 3) women with preeclampsia (N=10) in the index pregnancy were compared. Coded cell samples and associated clinical data were obtained from the University of Iowa Maternal Fetal Tissue Bank (IRB# 200910784). RNA was purified from the cells and used for real-time quantitative PCR to assess variation in receptor expression in children born to women with hypertensive disorders of pregnancy relative to control subjects. In children born to women with chronic hypertension, AVPR2 (-8.2 Fold Change, P<0.001), LNPEP (-13 Fold Change, P<0.001), CUL5 (-14 Fold Change, P<0.001), AVPR1b (-3.1 Fold Change, P=0.001), and OXTR (-4.3 Fold Change) were all significantly under-expressed when compared to normotensive controls. Samples from children born to women with preeclampsia had significantly lower expression of AVPR1a (-4.7 Fold Change, P<0.001), AVPR1b (-2.5 Fold Change, P=0.045), AVPR2 (-2.5 Fold Change, P=0.001), and OXTR (-2.8 Fold Change, P<0.001) when compared to non-preeclamptic samples. Differences in expression were also mirrored early in pregnancy in maternal blood in women with chronic hypertension. For example, CUL5 and LNPEP were decreased in the first trimester (-3.01 Fold Change, P=0.004 and -3.64 Fold Change P=0.007, respectively). The differences in gene expression in cord blood may be related to the future risk of hypertension later in life for children born to women with hypertensive diseases in pregnancy.

Abstract P132: Differential and Sex Dependent Expression of Vasopressin Receptors by B Cells, NK Cells, and Dendritic Cells

Arginine vasopressin (AVP) has been shown to play a role in preeclampsia, a hypertensive and immune-mediated disorder in pregnancy. Chronic infusion of AVP during gestation into wild-type mice results in the pregnancy-specific physiological changes (hypertension, kidney damage, fetal growth restriction) as well as increased CD4+ T H 1 and T H 17 associated cytokine responses observed in human pregnancies affected by preeclampsia. Further, human CD4+ T cells isolated from preeclamptic women were found to differentially express AVP receptors (AVPRs) 1a and 2 compared to control pregnancies. Abnormalities in other immune cells are seen during preeclampsia, including auto-antibody production (B cells), poor placental development (natural killer (NK) cells), and increased pro-inflammatory T cells responses (via dendritic cells (DC)). We, therefore, hypothesize that B cells, NK cells, and DC express AVPRs. To begin to understand 1) the expression pattern of AVPRs on CD4- lymphocytes and 2) if there are differences in expression between males and females, we evaluated the expression of AVPR 1a, 2, and 1b specifically on B cells, NK cells, and DC. Each subset was purified via negative selection from de-identified human peripheral blood mononuclear cells obtained through Leukocyte Reduction System (LRS) cone donors at the DeGowin Blood Center followed by qPCR for AVPR 1a, 2, and 1b expression (N=6 per cell type). B cells, NK cells, and DC expressed all three AVPRs 1a, 2, and 1b. All three lymphocyte populations showed a lower expression of AVPR1b compared to expression of 1a and 2, with B cells having the lowest expression of AVPR1b (p<0.05). Interestingly, while B cells and NK cells showed no differences in expression based on sex of the donor, DC isolated from male donors more highly expressed AVPR1b compared to female donors (p=0.0035). In conclusion, we demonstrate that B cells, NK cells, and DC highly express AVPR1a and 2, and that DC expression of AVPRs is sex dependent. Further investigation into the utilization of these receptors by these immune cells and the potential impact of sex-specific differences may elucidate newly identified mechanisms of AVP and immune interactions in not only preeclampsia, but possibly other cardiovascular-related diseases as well.

An integrated prediction model of recurrence in endometrial endometrioid cancers

Objectives: Endometrial cancer incidence and mortality are rising in the US. Disease recurrence has been shown to have a significant impact on mortality. However, to date, there are no accurate and validated prediction models that would discriminate which individual patients are likely to recur. Reliably predicting recurrence would be of benefit for treatment decisions following surgery. We present an integrated model constructed with comprehensive clinical, pathological and molecular features designed to discriminate risk of recurrence for patients with endometrioid endometrial adenocarcinoma. Subjects and methods: A cohort of endometrioid endometrial cancer patients treated at our institution was assembled. Clinical characteristics were extracted from patient charts. Primary tumors from these patients were obtained and total tissue RNA extracted for RNA sequencing. A prediction model was designed containing both clinical characteristics and molecular profiling of the tumors. The same analysis was carried out with data derived from The Cancer Genome Atlas for replication and external validation. Results: Prediction models derived from our institutional data predicted recurrence with high accuracy as evidenced by areas under the curve approaching 1. Similar trends were observed in the analysis of TCGA data. Further, a scoring system for risk of recurrence was devised that showed specificities as high as 81% and negative predictive value as high as 90%. Lastly, we identify specific molecular characteristics of patient tumors that may contribute to the process of disease recurrence. Conclusion: By constructing a comprehensive model, we are able to reliably predict recurrence in endometrioid endometrial cancer. We devised a clinically useful scoring system and thresholds to discriminate risk of recurrence. Finally, the data presented here open a window to understanding the mechanisms of recurrence in endometrial cancer.

A Prediction Model for Preoperative Risk Assessment in Endometrial Cancer Utilizing Clinical and Molecular Variables

The utility of comprehensive surgical staging in patients with low risk disease has been questioned. Thus, a reliable means of determining risk would be quite useful. The aim of our study was to create the best performing prediction model to classify endometrioid endometrial cancer (EEC) patients into low or high risk using a combination of molecular and clinical-pathological variables. We then validated these models with publicly available datasets. Analyses between low and high risk EEC were performed using clinical and pathological data, gene and miRNA expression data, gene copy number variation and somatic mutation data. Variables were selected to be included in the prediction model of risk using cross-validation analysis; prediction models were then constructed using these variables. Model performance was assessed by area under the curve (AUC). Prediction models were validated using appropriate datasets in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A prediction model with only clinical variables performed at 88%. Integrating clinical and molecular data improved prediction performance up to 97%. The best prediction models included clinical, miRNA expression and/or somatic mutation data, and stratified pre-operative risk in EEC patients. Integrating molecular and clinical data improved the performance of prediction models to over 95%, resulting in potentially useful clinical tests.

Population Substructure Has Implications in Validating Next-Generation Cancer Genomics Studies with TCGA

In the era of large genetic and genomic datasets, it has become crucially important to validate results of individual studies using data from publicly available sources, such as The Cancer Genome Atlas (TCGA). However, how generalizable are results from either an independent or a large public dataset to the remainder of the population? The study presented here aims to answer that question. Utilizing next generation sequencing data from endometrial and ovarian cancer patients from both the University of Iowa and TCGA, genomic admixture of each population was analyzed using STRUCTURE and ADMIXTURE software. In our independent data set, one subpopulation was identified, whereas in TCGA 4⁻6 subpopulations were identified. Data presented here demonstrate how different the genetic substructures of the TCGA and University of Iowa populations are. Validation of genomic studies between two different population samples must be aware of, account for and be corrected for background genetic substructure.

Molecular Characterization of Non-responders to Chemotherapy in Serous Ovarian Cancer

Nearly one-third of patients with high-grade serous ovarian cancer (HGSC) do not respond to initial treatment with platinum-based therapy. Genomic and clinical characterization of these patients may lead to potential alternative therapies. Here, the objective is to classify non-responders into subsets using clinical and molecular features. Using patients from The Cancer Genome Atlas (TCGA) dataset with platinum-resistant or platinum-refractory HGSC, we performed a genome-wide unsupervised cluster analysis that integrated clinical data, gene copy number variations, gene somatic mutations, and DNA promoter methylation. Pathway enrichment analysis was performed for each cluster to identify the targetable processes. Following the unsupervised cluster analysis, three distinct clusters of non-responders emerged. Cluster 1 had overrepresentation of the stage IV disease and suboptimal debulking, under-expression of miRNAs and mRNAs, hypomethylated DNA, “loss of function” TP53 mutations, and the overexpression of genes in the PDGFR pathway. Cluster 2 had low miRNA expression, generalized hypermethylation, MUC17 mutations, and significant activation of the HIF-1 signaling pathway. Cluster 3 had more optimally cytoreduced stage III patients, overexpression of miRNAs, mixed methylation patterns, and “gain of function” TP53 mutations. However, the survival for all clusters was similar. Integration of genomic and clinical data from patients that do not respond to chemotherapy has identified different subgroups or clusters. Pathway analysis further identified the potential alternative therapeutic targets for each cluster.

The miR-503 cluster is coordinately under-expressed in endometrial endometrioid adenocarcinoma and targets many oncogenes, cell cycle genes, DNA repair genes and chemotherapy response genes

Background

The miR-503 miRNA cluster, located at Xq23.1, is composed of six miRNAs; miR-424, miR-503, miR-542, miR-450a-1, miR-450a-2 and miR-450b. Numerous studies have focused on the relationship of one or two members of the cluster and various human cancers. Here, we suggest that the entire cluster as a single coordinately expressed polycistron transcribed from a single promoter in endometrial endometrioid adenocarcinoma (EEA).

Subjects and methods

A tissue panel composed of twenty histologically confirmed endometrial endometrioid adenocarcinomas (EEA) and four benign endometrium was assembled under informed consent. Expression of each member of the miR-503 cluster was determined by quantitative PCR and differences in expression between EEA and benign tissues were assessed via the standard ΔΔCt method. In addition, the role of promoter methylation status in miRNA expression was examined in Ishikawa H cells following exposure to the cytidine analog Decitabine.

Results

Expression of each member of the miR-503 cluster is significantly downregulated in EEA in our tumor sample. Both in our tumor sample and in The Cancer Genome Atlas (TCGA) there is evidence of highly correlated expression further supporting the idea that the miR-503 cluster is a polycistron. Looking at each member of the miR-503 cluster we were able to identify 55 unique experimentally validated target genes which include a substantial number of genes involved in carcinogenesis, DNA damage response, cell cycle regulation and chemotherapeutic response. We also found preliminary evidence that regulation of the miR-503 cluster is governed by methylation of the promoter in EEA.

Conclusion

The totality of the data presented here strongly suggest that the miR-503 cluster as a whole merits further investigation as an important potential therapeutic target in EEA.

Nanoparticle-Based Delivery of CRISPR/Cas9 Genome-Editing Therapeutics

The recent progress in harnessing the efficient and precise method of DNA editing provided by CRISPR/Cas9 is one of the most promising major advances in the field of gene therapy. However, the development of safe and optimally efficient delivery systems for CRISPR/Cas9 elements capable of achieving specific targeting of gene therapy to the location of interest without off-target effects is a primary challenge for clinical therapeutics. Nanoparticles (NPs) provide a promising means to meet such challenges. In this review, we present the most recent advances in developing innovative NP-based delivery systems that efficiently deliver CRISPR/Cas9 constructs and maximize their effectiveness.

Abstract 015: Reduced Placental Expression of Regulator of G Protein Signaling-2 (RGS2) in Preeclampsia: Association, Consequence, and Cause

To date, the early-gestational mechanisms driving the pathogenesis of preeclampsia (PreE) remain largely unclear. However, altered G protein signaling has been implicated in PreE, including alterations in GPCR agonists such as vasopressin, endothelin, and angiotensin. Regulator of G protein Signaling 2 (RGS2) is an endogenous terminator of Gαq signaling, and mutations in the Rgs2 gene are linked to hypertension and increased risk of developing PreE. Therefore, we hypothesized reduced placental RGS2 may increase the risk of developing PreE by disinhibiting Gαq signaling. In silico reanalysis of a publicly-available microarray dataset (GSE75010) revealed a significant reduction in Rgs2 mRNA in placentas from PreE pregnancies compared to controls (Con n=35, PreE n=49, p<0.05). We confirmed this reduction in Rgs2 mRNA by qPCR using human placental tissue samples (PreE 19% of Con, n=11 vs 9, p<0.05). To examine if reduced feto-placental RGS2 was sufficient to induce PreE phenotypes, wildtype C57BL/6J female mice were mated with Rgs2 -deficient ( Rgs2 -KO) sires or wildtype littermate sires. Dams mated with Rgs2 -KO sires developed diastolic hypertension (Con 92 ± 2 vs Rgs2 -KO 98.2 ± 2 [24 hr avg mmHg]; p<0.05 vs pregnant control and pre-pregnancy Rgs2 -KO) and increased proteinuria compared to dams mated with littermate sires (18.2 ± 2.2, n=7 vs 28.4 ± 2.8, n=10 mg/day, p<0.05). Preliminary histological analysis of placentas from dams mated with an Rgs2 -KO sire suggest decreased spiral artery number and diameter (SA Number: Con 7.7 ± 0.2 vs Rgs2 -KO 5.6 ± 0.4, SA Diameter: Con 128 ± 3 vs Rgs2 -KO 86 ± 12). Previous studies have outlined a CRE element in the Rgs2 promoter that is critical for transcriptional regulation of Rgs2 . Thus, we hypothesized loss of cAMP/CREB regulation may lead to reduced RGS2 in human PreE. Indeed, reduced phosphorylated CREB (p-CREB) binding was observed in PreE placentas (Con 0.146 ± 0.024 vs PreE 0.070 ± 0.021 p<0.05). However, loss of p-CREB was not due to decreases in cAMP levels (Con 1.69 ± 0.35 vs PreE 2.18 ± 0.18 nM). These data support a role for reduced placental RGS2 in the pathogenesis of PreE, and demonstrate that changes in p-CREB regulation may explain the loss of RGS2 expression in placental trophoblasts.

Abstract P316: Effects of Paternal Contribution of a Null Allele of Regulator of G Protein Signaling-2 ( Rgs2 ) upon the Placental Transcriptome of C57BL/6J Mice

Preeclampsia (PreE), a cardiovascular disorder of pregnancy, remains a major cause of maternal and fetal mortality worldwide. The early etiology of the disorder is unclear, though increased G protein-coupled receptor signaling has been implicated. Regulator of G protein Signaling-2 (RGS2) is a negative regulator of G protein signaling, and mutations of RGS2 have been associated with increased risk for PreE in humans. Our ongoing work has demonstrated that breeding wildtype C57BL/6J dams with Rgs2 -deficient ( Rgs2 -KO; B6.129P2- Rgs2 tm1Dgen /Mmnc) sires is sufficient to cause ~50% reduced placental expression of Rgs2 mRNA, and to induce hypertension, renal and placental morphological phenotypes typical of PreE in the wildtype dams. To test the hypothesis that reduced RGS2 (via paternal contribution of an Rgs2 -null allele) is sufficient to cause molecular changes within the placenta that are typical of PreE, we performed RNA sequencing on placentas collected on gestational day 12.5 from C57BL/6J dams mated with either Rgs2 -KO sires or wildtype littermates of these sires. RNA was isolated and sequenced using an Illumina HiSeq 4000. Transcript counts were quantified and aligned to the mouse genome (UCSC genome browser) using Kallisto, followed by differential gene expression analysis using DEseq2 (FDR = 0.1). 726 genes were differentially expressed (479 up, 247 down), including some ( Hsd11b2 (up), Adm (down)), that are similarly changed in human PreE placenta (PMID: 28618048 & 26268791). Ingenuity Pathway Analysis indicated that reduced placental Rgs2 expression was associated with mitochondrial dysfunction, unfolded protein response, and oxidative stress (all p < 1e-3), which also parallels findings in human PreE placenta. Collectively these data support the conclusion that reduced Rgs2 expression in the feto-placental unit is sufficient to induce transcriptomic changes within the placenta that are typical of PreE.

Elevated vasopressin in pregnant mice induces T-helper subset alterations consistent with human preeclampsia

The pathogenesis of preeclampsia (PreE), a hypertensive disorder of pregnancy, involves imbalanced T helper (TH) cell populations and resultant changes in pro- and anti-inflammatory cytokine release. Elevated copeptin (an inert biomarker of arginine vasopressin (AVP)), secretion precedes the development of symptoms in PreE in humans, and infusion of AVP proximal to and throughout gestation is sufficient to initiate cardiovascular and renal phenotypes of PreE in wild-type C57BL/6J mice. We hypothesize that AVP infusion in wild-type mice is sufficient to induce the immune changes observed in human PreE. AVP infusion throughout gestation in mice resulted in increased pro-inflammatory interferon γ (IFNg) (TH1) in the maternal plasma. The TH17-associated cytokine interleukin (IL)-17 was elevated in the maternal plasma, amniotic fluid, and placenta following AVP infusion. Conversely, the TH2-associated anti-inflammatory cytokine IL-4 was decreased in the maternal and fetal kidneys from AVP-infused dams, while IL-10 was decreased in the maternal kidney and all fetal tissues. Collectively, these results demonstrate the sufficiency of AVP to induce the immune changes typical of PreE. We investigated if T cells can respond directly to AVP by evaluating the expression of AVP receptors (AVPRs) on mouse and human CD4+ T cells. Mouse and human T cells expressed AVPR1a, AVPR1b, and AVPR2. The expression of AVPR1a was decreased in CD4+ T cells obtained from PreE-affected women. In total, our data are consistent with a potential initiating role for AVP in the immune dysfunction typical of PreE and identifies putative signaling mechanism(s) for future investigation.

Dysregulation of miR-181c expression influences recurrence of endometrial endometrioid adenocarcinoma by modulating NOTCH2 expression: An NRG Oncology/Gynecologic Oncology Group study

OBJECTIVE

Endometrial cancer can be diagnosed early and cured, yet cases that recur portend a very poor prognosis with over 10,000 women succumbing to the disease every year. In this study we addressed the question of how to recognize cases likely to recur early in the course of therapy using dysregulation of tumor microRNAs (miRNAs) as predictors.

METHODS

Using the tissue collection from Gynecologic Oncology Group Study-210, we selected and analyzed expression of miRNAs in 54 recurrent and non-recurrent cases. The three most common histologic types, endometrioid adenocarcinoma (EEA), serous adenocarcinoma (ESA) and carcinosarcoma (UCS), were analyzed as three independent sets and their miRNA expression profiles compared.

RESULTS

Only one miRNA was statistically different between recurrent and non-recurrent cases, and in only one histologic type: significant down-regulation of miR-181c was observed in EEA recurrence. Using several well-known databases to assess miR-181c targets, one target of particular relevance to cancer, NOTCH2, was well supported. Using The Cancer Genome Atlas and our validation tumor panel from the GOG-210 cohort, we confirmed that NOTCH2 is significantly over-expressed in EEA. In the most relevant endometrial adenocarcinoma cell model, Ishikawa H, altering miR-181c expression produces significant changes in NOTCH2 expression, consistent with direct targeting.

CONCLUSIONS

Our findings suggest that increased NOTCH2 via loss of miR-181c is a significant component of EEA recurrence. This presents an opportunity to develop miR-181c and NOTCH2 as markers for early identification of high risk cases and the use of NOTCH inhibitors in the prevention or treatment of recurrent disease.

Abstract P262: Vasopressin Receptors Regulate Immune Responses in Preeclampsia

The pathogenesis of preeclampsia (PE) involves imbalanced T helper (T H ) cell populations and resultant changes in pro- and anti-inflammatory cytokine release. Elevated secretion of arginine vasopressin (AVP) precedes the development of symptoms in PE in humans, and chronic infusion of AVP (24 ng/hr s.c.) throughout gestation is sufficient to initiate cardiovascular, renal, and immune phenotypes of PE in wild-type C57BL/6J mice. We hypothesize that increased AVP signaling may mediate the immune changes observed in PE. AVP infusion throughout gestation in mice resulted in increased pro-inflammatory IFNγ (T H 1) in the maternal plasma (N=7, p<0.05) and IL-17 (T H 17) in the placenta (N≥10, p<0.001). The T H 2-associated anti-inflammatory cytokines IL-4 and IL-10 were decreased in maternal kidney (IL-4: N=8, p<0.05; IL-10: N=5, p<0.01) and fetal kidney (IL-4: N=5, p<0.05; IL-10: N=5, p<0.05) of AVP-infused dams. To elucidate the receptor dependency of these effects, AVP-infused dams were simultaneously treated with chronic infusion of AVP V 1A and/or V 2 receptor antagonists (22 ng/hr s.c). Combined blockade of V 1a +V 2 receptors by conivaptan, as well as specifically blocking V 2 by tolvaptan, corrected AVP induced reductions in IL-4 in maternal (conivaptan: N=5, p<0.05; tolvaptan: N=5, p<0.0.0001) and fetal kidneys (conivaptan: N=5, p<0.0001; tolvaptan: N=5, p<0.05). These data implicate V 2 as the receptor involved in kidney IL-4 deficiency in PE, whereby blockade of V 2 restores IL-4, preventing inflammation. Combined blockade of V 1A +V 2 receptors by conivaptan corrected the placental loss of IL-4 (N=5, p<0.05), whereas blockade of either receptor alone was insufficient, suggesting loss of placental IL-4 via AVP is mediated by both V 1a and V 2 receptors. In contrast, increased placental IL-17 was only corrected by selective blockade of V 1A by relcovaptan (N=5, p<0.05), suggesting a novel role for V1a receptor in pro-inflammatory placental IL-17 production in PE. Collectively these results demonstrate the sufficiency of AVP to induce the immune changes typical of PE, and support a dominant role for V 1A in the induction of pro-inflammatory IL-17 (T H 17) release versus a dominant role for V 2 receptors in the suppression of anti-inflammatory IL-4 (T H 2) release.

Abstract P261: Vasopressin System Components are Dysregulated in Human Preeclamptic Placenta

Preeclampsia (PE) is a cardiovascular disorder of late pregnancy characterized by pregnancy-specific onset of hypertension and proteinuria. Although initiating events leading to PE development remain unclear, emerging studies suggest arginine vasopressin (AVP) signaling may contribute to PE pathogenesis, as elevated circulating copeptin (a stable biomarker of AVP secretion) levels precede the onset of human PE, and chronic infusion of AVP into wildtype mice phenocopies PE. Here, we tested the hypothesis that AVP signaling is dysregulated in PE placenta by performing in-silico reanalysis of a publically available gene expression dataset derived from placentas of human PE and normal pregnancies (GSE75010). Significant increases in expression [log 2 values] of AVP (Con: 6.96 ± 0.02, PE: 7.03 ± 0.17, p=0.005) and its receptors AVPR1a (Con: 5.73 ± 0.02, PE: 5.80 ± 0.02, p=0.03) and OXTR (Con: 6.58 ± 0.02, PE: 6.65 ± 0.02, p=0.003) were observed in PE placentas (n=80) compared to normal placentas (n=77). Preeclamptic placentas also displayed an enrichment in a hypoxic gene signature, as shown by gene set enrichment analyses (NES: 1.75, FDR q<0.001, FWER p <0.001), suggesting that these placentas exhibited increased hypoxia-related signaling. Interestingly, AVPR1a expression as well as OXTR is positively and significantly correlated with the expression of two hypoxia-inducible genes HK2 and DDIT4 ( AVPR1a v HK2 : r 2 =0.04, p=0.02, AVPR1a v DDIT4 : r 2 =0.06, p=0.003, OXTR v HK2 : r 2 =0.05, p=0.007, OXTR v DDIT4 : r 2 =0.04, p=0.008). To further elucidate the role hypoxia may play in promoting AVP signaling, HTR8/SVNeo cells (immortalized human first trimester trophoblasts) were treated with the hypoxia mimetic dimethyloxallyl glycine (DMOG). DMOG incubation did not significantly alter the expression of AVP and AVPR1a . Unexpectedly, a marked reduction in OXTR expression was observed upon DMOG treatment. In summary, these data suggest that 1) components of the AVP signaling pathway are aberrantly expressed in human PE placentas, 2) PE placentas exhibit a gene expression signature consistent with increased canonical hypoxia signaling, and 3) hypoxia may not be the cause of elevated placental AVP , AVPR1a , and OXTR expression in human PE.

Abstract 144: Reduced Placental Regulator of G-Protein Signaling-2 (RGS2) and Preeclampsia

The early mechanisms and genetic risk factors driving the pathogenesis of preeclampsia (PE), a cardiovascular disorder of pregnancy, remain largely unclear. Various hormone activators of Gα q second-messenger signaling pathways have been implicated in PE. Regulator of G-protein Signaling 2 (RGS2) acts as an endogenous terminator of Gα q signaling and previous studies identified a SNP (rs4606), which results in reduced RGS2 mRNA, as a risk factor for development of PE and its sequelae. We hypothesized reduced placental expression of RGS2 may precipitate the development of PE due to disinhibited Gα q signaling. In silico reanalysis of publically available dataset GSE75010 revealed RGS2 mRNA is reduced in placentas from pre-term PE pregnancies compared to normal pre-term pregnancies (con: 8.73 ± 0.07 n=35, PE: 8.37 ± 0.055 n=49, p<0.05). Using human placental tissue samples from the University of Iowa Maternal-Fetal Tissue Bank, we confirmed RGS2 mRNA is reduced in PE placentas (19% of control, p<0.05), despite a lack of correlation between the rs4606 SNP and PE. Additionally, in further reanalysis of other datasets, RGS2 mRNA is among the highest-expressed RGS member in normal human placenta, and appears to be selectively reduced in syncytio- and invasive cytotrophoblasts during PE (GSE93839, -26.3%, -23.3% of control). We next examined RGS2 expression in mouse placenta by FISH and found RGS2 mRNA colocalizes with markers of syncytiotrophoblast II (GCMA) and spongiotrophoblast (Tpbpα) layers. To test the effect of RGS2 loss during pregnancy, wildtype C57BL/6J female mice were mated with RGS2-deficient sires and developed diastolic hypertension, placental hypoxia by HIF1α ELISA (con 0.144±0.004, RGS2-KO 0.155±0.004 AU, p<0.05, n=5 each), and reduced placental PlGF mRNA (fold; con=1.0 n=7, RGS2-KO=0.23 n=12, p<0.05), compared to females mated with RGS2 littermate sires. These data support the concept that loss of RGS2 may contribute to the pathogenesis of PE rather than simply correlating with the disorder. Taken together, we have shown placental RGS2 is suppressed in PE, RGS2 is present in cytoplasm of specific layers of trophoblasts, and loss of feto-placental RGS2 is sufficient to cause placental hypoxia and maternal diastolic hypertension.

Abstract P270: First Trimester Elevation in Circulating Endothelin-1 and Arterial Stiffness are Predictive of Late Pregnancy Preeclampsia

Preeclampsia (PE) is characterized by late pregnancy hypertension and proteinuria. PE causes significant morbidity for the maternal-fetal unit. Circulating endothelin-1 (ET-1), a potent vasoconstrictor, is elevated at the time of diagnosis of human PE. In addition, women with PE demonstrate arterial stiffness as early as the end of the first trimester. However, it is unknown if arterial stiffness is associated with a first trimester elevation in ET-1 and post-delivery placental ET-1. We hypothesized that 1) first trimester plasma ET-1 is elevated and is associated with arterial stiffness in women who develop PE; 2) first trimester ET-1 is predictive of PE; and 3) placental ET-1 is increased in PE. To address these questions, we performed a nested case-control study in women at risk for PE. First trimester plasma ET-1 was measured via ELISA; aortic stiffness and carotid beta-stiffness (CβS) were measured by carotid-femoral pulse-wave velocity (CFPWV) and carotid tonometry/ultrasound, respectively. While the maternal age of controls (n=126; age 30 ± 0.45 years) and PE (n=15; age 31 ± 1.3 years) were similar, the PE group had a higher first trimester BMI (35 ± 3 vs. 29 ± 1 kg/m 2 , p = 0.01), systolic (125 ± 2 vs. 113 ± 1 mmHg, p< 0.01) and diastolic blood pressure (68 ± 2 vs. 60 ± 1 mmHg, p< 0.01) compared with controls. In addition, first trimester plasma ET-1 (2.7 ± 0.4 vs. 2.0 ± 0.2 pg/mL, p < 0.01), CFPWV (7.2 ± 0.5 vs. 6.1 ± 0.2 m/s, p = 0.016), and CβS (8.4 ± 1.9 vs. 6.3 ± 0.3, p = 0.055) were higher in the PE group. Consistent with previous studies, third trimester plasma ET-1 was elevated in the PE group (2.9 ± 1.1 vs. 1.6 ± 0.1 pg/mL, p < 0.01) which paralleled a 2.5 fold increase in placental decidual ET-1 mRNA (p < 0.0001). ROC analyses showed that first trimester plasma ET-1 (AUC=0.71, p < 0.001) and CFPWV (AUC=0.70, p=0.014) were predictive of PE. This study supports the novel concept that elevated ET-1 in preeclampsia begins early in the first trimester and is associated with premature arterial stiffness. Further, these novel data suggest that ET-1 may play an important role in the first trimester prediction and pathogenesis of preeclampsia.

Abstract 172: Vascular Smooth Muscle Cell Activation is Regulated by miR-25 Induced miR-9 Suppression of Nox4 and Myocardin

Vascular smooth muscle cell (SMC) de-differentiation with subsequent migration and proliferation into the subendothelial space is central to the progression of cardiovascular diseases. The Nox4 NADPH oxidase (Nox4) is implicated in maintaining the differentiated phenotype of SMC in part through myocardin, a master regulator of SMC gene expression. However, this process is poorly understood. We hypothesized that microRNAs (miR)-mediate changes in Nox4 expression and regulate SMC differentiation. Treatment of human SMCs with a miR-9 or miR-25 mimic silenced Nox4 mRNA through binding to the Nox4 3’UTR. However, only miR-25 was sufficient to downregulate Nox4 protein levels. We found that miR-25 induced the expression of miR-9 through a novel mechanism involving demethylation of the miR-9 promoter by Tet methylcytosine dioxygenase 2 (TET2). Inhibition of miR-9 induction by miR-25 with a miR-9 inhibitor restored Nox4 protein expression to basal levels. Furthermore, the miR-25-mediated decrease in Nox4 protein was ameliorated by inhibiting the proteasome with MG132. These data suggest a novel mechanism wherein miR-9 and miR-25 regulate Nox4 through both translational suppression and proteosomal degradation. Overexpression of miR-9 or miR-25 in human SMCs (1) suppressed myocardin mRNA and protein expression; (2) decreased expression of multiple SMC differentiation genes; and (3) was sufficient to induce cell migration. Thrombin and tumor necrosis factor increased the expression of miR-9 and miR-25 in human SMCs and inhibition of miR-9 prevented thrombin-mediated decrease in myocardin and SMC migration. Mir-9 and miR-25 levels were increased in SMCs derived from balloon injured rat aorta as compared to medial SMCs and in murine carotid artery ten days post carotid injury. A miR-9 inhibitor decreased neointimal formation by more than 50% in following partial carotid ligation in mice. These findings identify miR-9/Nox4 as a novel regulatory pathway of SMC differentiation and a potential therapeutic target in vascular disease.

Placenta-Specific Protein 1 Expression in Human Papillomavirus 16/18-Positive Cervical Cancers Is Associated With Tumor Histology

OBJECTIVE

Expression of the trophoblast-specific gene placenta-specific protein 1 (PLAC1) has been detected in a wide variety of cancers. However, to date, PLAC1 expression has not been shown in cervical cancer. We have carried out a preliminary study that shows for the first time that PLAC1 is expressed in cervical cancers.

METHODS

A total of 16 primary cervical tumors were obtained from patients shown to be human papillomavirus (HPV) 16/18 positive. Total cellular RNA, genomic DNA, and total protein were purified from each tumor. These materials were then used to determine PLAC1 expression, TP53 mutation status, and p53 expression.

RESULTS

The PLAC1 expression was demonstrated in all 16 primary cervical tumors. The highest levels of expression were found in the more aggressive squamous and adenosquamous histologic types compared with adenocarcinomas. Moreover, the proportion of total PLAC1 message coming from the P1 promoter, also termed the distal or cancer promoter, was significantly greater in the more aggressive squamous and adenosquamous histologic types compared with adenocarcinomas. Finally, in spite of all 16 tumors being HPV-16/18 positive, 3 of 8 squamous cell cancers and 2 of 5 adenocarcinomas expressed wild-type p53 protein. Consistent with the recently shown suppression of the PLAC1P1 promoter by wild-type p53, these p53 positive tumors displayed among the lowest P1-specific PLAC1 expression levels.

CONCLUSIONS

The PLAC1 expression has been demonstrated for the first time in cervical cancers. This preliminary study has further revealed a complex relationship between PLAC1 expression, cervical cancer histologic type, p53, and HPV type that requires further investigation.

p53 mutation status is a primary determinant of placenta-specific protein 1 expression in serous ovarian cancers

Placenta-specific protein 1 (PLAC1) expression is co-opted in numerous human cancers. As a consequence of PLAC1 expression, tumor cells exhibit enhanced proliferation and invasiveness. This characteristic is associated with increased aggressiveness and worse patient outcomes. Recently, the presence of the tumor suppressor p53 was shown in vitro to inhibit PLAC1 transcription by compromising the P1, or distal/cancer, promoter. We sought to determine if this phenomenon occurs in primary patient tumors as well. Furthermore, we wanted to know if p53 mutation influenced PLAC1 expression as compared with wild-type. We chose to study serous ovarian tumors as they are well known to have a high rate of p53 mutation. We report herein that the phenomenon of PLAC1 transcription repression does occur in serous ovarian carcinomas but only when TP53 is wild-type. We find that mutant or absent p53 protein de-represses PLAC1 transcription. We further propose that the inability of mutant p53 to repress PLAC1 transcription is due to the fact that the altered TP53 protein is unable to occupy a putative p53 binding site in the PLAC1 P1 promoter thus allowing transcription to occur. Finally, we show that PLAC1 transcript number is significantly negatively correlated with patient survival in our samples. Thus, we suggest that characterizing tumors for TP53 mutation status, p53 protein status and PLAC1 transcription could be used to predict likely prognosis and inform treatment options in patients diagnosed with serous ovarian cancer.

Abstract P177: Reduced Expression of Regulator of G-Protein Signaling-2 (RGS2) in the Placenta During Preeclampsia

Preeclampsia (PE) is a serious cardiovascular condition of late pregnancy. Genetic risk factors and the early-gestational etiology remain largely unclear, though evidence supports excessive activation of Gαq signaling within the placenta in response to various hormones including vasopressin, endothelin, and angiotensin. Regulator of G-protein Signaling 2 (RGS2) acts as an endogenous terminator of Gαq signaling, and previous association studies have identified an increased risk for PE and its sequelae in women carrying a single nucleotide polymorphism that is expected to reduce levels of RGS2. We hypothesized that RGS2 is expressed in placental trophoblasts, and that reduced expression of RGS2 in placental tissue may represent a risk factor for the development of PE. Whole placenta samples and clinical data from preeclamptic and clinically-matched control pregnancies were obtained from the University of Iowa Maternal-Fetal Tissue Bank (IRB#200910784) and examined for mRNA levels of the B/R4 family of RGS proteins, including RGS2. Of the members examined (RGS2, -3, -4.2, -4.3, -4.4, -4.5, and -5) in control placentas (n=9), only RGS2 (Ct 28.8±0.7 vs 18S Ct 12.1±0.4) and RGS4.3 (Ct 23.0±0.4 vs 18S Ct 13.3±0.3) transcripts were expressed above background levels. RGS2 protein expression was then confirmed in human placental tissues by Western blot. RGS2 mRNA expression was 3-fold higher in fetal (amniotic, p<0.05) layers than maternal (decidual) layers. In preeclamptic placenta (n=11), RGS2 may be suppressed (1.0±0.4 vs 0.2±0.3-fold, p=0.1) while RGS4.3 remains unchanged (1.0±0.4 vs 1.1±0.4 fold, p=0.8). Initial immunohistochemical detection confirms cytoplasmic localization of RGS2 in trophoblasts of wildtype mouse placenta, despite exclusive nuclear localization in other tissues. We conclude that human placenta expresses RGS2, and that this expression may be suppressed during preeclampsia. Loss of RGS2 expression may result in disinhibited trophoblast Gαq signaling, and ultimately placental insufficiency.

Abstract P323: Arginine Vasopressin and Indoleamine 2,3 Dioxygenase: The Early Immunovascular Interface in Preeclampsia

Preeclampsia (PreE), a hypertensive disease of pregnancy, causes maternal and fetal health complications. Abnormal placental development/angiogenesis and poor immunoregulation (involving T cells, Indoleamine 2, 3 Dioxygenase (IDO), and dendritic cells) are central to the development of PreE. IDO, produced by regulatory immune cells, degrades tryptophan to arrest inflammatory T cell proliferation and induces T regulatory cell development. Our data and others show decreased IDO placental expression from human preeclamptic pregnancies. We published that deletion of IDO (IDO KO) in pregnant mice results in pathognomonic glomerular endotheliosis, proteinuria, and intrauterine growth restriction, hallmark features of PreE. Our group also demonstrated that, plasma copeptin, a stable bio-marker of vasopressin (AVP) secretion, is elevated early in human PreE pregnancies; and AVP infusion into wild-type C57BL/6J dams phenocopies human PreE, including increased inflammatory T cells and highly activated dendritic cells. Here, we test our hypothesis that AVP (via copeptin measurement) is elevated in the IDO KO mouse model of PreE and that IDO activity is decreased in the AVP mouse model of PreE. Copeptin, measured by ELISA, was elevated in both the placenta (2.4±0.2 vs. 1.7±0.2 pg/mg, p=0.03) and maternal serum (2.1±0.2 vs. 1.2±0.4 pg/mg, p=0.03) from IDO KO pregnancies compared to wild-type at gestational day (GD) 18. In our chronic infusion of AVP model of PreE (24 ng/hour), GD 18 colorimetric IDO activity was decreased by 22% in the maternal kidney (N=10 per group) and by 27% in the amniotic fluid (saline N=8 vs. AVP N=12) of AVP-infused dams in comparison to controls. Collectively, these data demonstrate an inverse relationship between IDO activity and copeptin expression in PreE pregnancies. As both IDO and AVP sit at the crossroads between vascular and immune dysfunction, these data suggest that the IDO-AVP interaction may contribute to the maternal and fetal renal phenotype observed in preeclampsia.

Differentially expressed genes in preimplantation human embryos: potential candidate genes for blastocyst formation and implantation

Purpose

The aim of this study was to determine which genes and gene pathways are differentially expressed when comparing human blastocysts with cleavage-stage embryos.

Methods

We individually assessed gene expression in preimplantation human embryos at cleavage (n = 3) and blastocyst (n = 3) stages. Gene expression patterns were then validated in publically available datasets and then independently validated in vitro with additional human embryos using TaqMan gene expression assays. Immunolocalization studies were conducted to identify protein expression in intact blastocyst-stage embryos.

Results

Compared to cleavage-stage embryos, blastocyst-stage embryos differentially expressed 51 genes (p < 0.001), with overrepresentation in amoebiasis pathways and pathways in cancer. Of these 51 genes, 21 were found to be independently validated in a separate, publically available dataset, with a substantial agreement with our initial findings (κ = 0.8). In an independent set of cleavage- and blastocyst-stage embryos, we validated that six of eight tested genes were differentially expressed (p < 0.05) by RT-qPCR. Immunofluorescence studies documented the presence of two studied proteins in the trophectoderm of blastocyst-stage embryos.

Conclusions

Differentially expressed genes may be implicated in the invasion and proliferation of the early embryo. Our research highlights specific genes that may be further studied for their role in the implantation process and additionally raises questions about localized gene and/or protein expression in the trophectoderm, which could affect protocols for, and interpretation of, trophectoderm biopsies performed in in vitro fertilization cycles.

Electronic supplementary material

The online version of this article (doi:10.1007/s10815-016-0745-x) contains supplementary material, which is available to authorized users.

Cullin-5, a ubiquitin ligase scaffold protein, is significantly underexpressed in endometrial adenocarcinomas and is a target of miR-182

Altered expression of cullin-5 (CUL5), a member of the cullin-RING E3 ubiquitin ligase family, has been implicated in a number of types of cancers including breast, cervical and hepatocellular cancers. In the present study, we found that CUL5 expression was significantly decreased in both endometrioid and serous endometrial adenocarcinomas with the more aggressive serous type displaying a higher reduction (−4.3-fold) than the less aggressive endometrioid type (−2.9-fold). Overexpression of CUL5 mRNA and protein in Ishikawa H endometrial cancer cells resulted in decreased cell proliferation and in a reduction in CUL5-RING E3 ligase downstream clients JAK2 and FAS-L. Finally, we demonstrated for the first time that CUL5 is a direct target of miR-182 that we previously showed to be significantly overexpressed in endometrial adenocarcinomas and we provided evidence that increased miR-182 expression is, at least in part, a result of demethylation of its upstream promoter. These data suggest a cascade in which miR-182 expression is epigenetically increased leading to decreased CUL5 expression and increased cellular proliferation. The final step in the cascade may be operating through a decrease in ubiquitination of pro-growth CUL5 ubiquitin ligase clients. This cascade offers a series of potential interventional steps involving epigenetic modification, miRNA and/or gene targeting and ubiquitination.