Estrogen Receptor Alpha Expression Research Articles

Abstract PO5-23-08: Adenylosuccinate lyase is essential for proliferation and mitochondrial function of endocrine therapy resistant breast cancer cells

Abstract Eighty percent of breast cancers express estrogen receptor alpha (ERα, ESR1) at the time of diagnosis. Endocrine therapy (ET) is the standard treatment that either block estrogen mediated ER activation (such as tamoxifen, fulvestrant) or suppress estrogen synthesis (such as exemestane, letrozole, or anastrozole). While ET is initially effective, emergence of ET-resistance is common and possess a major clinical challenge. Hence, there is an ongoing need to develop new treatments for ET-resistant-ERα positive breast cancer. In this study we investigated the role of adenylosuccinate lyase (ADSL), an enzyme of the de-novo purine biosynthesis pathway as a potential target of ET-resistant breast cancer. The protein level of ADSL in two independent ET-resistant cell line model LCC9 and T47D-4HT cells were significantly higher in comparison to its parental ET-sensitive cell lines, MCF7 and T47D cells, respectively. Transient knockdown of ADSL using two independent siRNA in both LCC9 and T47D-4HT cells results in a significant decrease of cell growth, colony, and spheroid formation. Notably, reduced ADSL levels in LCC9 cells prevented the cells from progressing from G1 to S phase of cell cycle with concurrent elevation of cyclin D1/D3, CDK2/4, and cyclin E. On the other hand, in T47D-4HT cells, ADSL reduction caused cells to accumulate in S-phase of cell cycle and showed lower levels of total cyclin D1 protein. Mechanistically, in LCC9 cells (but not in T47D-4HT cells), ADSL depletion induced DNA replication stress which activates (phosphorylate) ataxia-telangiectasia-mutated-and-Rad3-related kinase (ATR) and its major downstream effector checkpoint kinase 1 (Chk1) that in turn failed to de-phosphorylate the inhibitory-phospho-groups of cyclin-dependent kinase 2 (CDK2). In addition, ADSL depletion perturbed the mitochondrial function in both LCC9 and T47D-4HT cells. Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) was lower in both the cells along with the mitochondrial membrane potential. Pertinently, lower concentration of AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside), a product of ADSL enzyme function, partially rescued the cell growth and restored mitochondrial membrane potential in ADSL-depleted LCC9 cells. To further understand the global effects of ADSL depletion we performed RNA-sequencing of LCC9 and T47D-4HT cells after ADSL depletion and compared with respective control siRNA transfected cells followed by gene set enrichment analysis. Intriguingly, diverse effect was observed in LCC9 and T47D-4HT cells as very few genes were found to be commonly regulated between these two cell lines. Analysis of clinical data sets revealed high level of ADSL transcript was associated with adverse progression free survival and overall survival in breast cancer patients treated with endocrine therapies. Overall, our findings demonstrate that ADSL-mediated de novo purine synthesis is critical for cellular growth, proliferation, and mitochondrial function of endocrine therapy-resistant breast cancer cells. Therefore, targeting ADSL is a novel potential therapeutic approach for ERα positive ET- resistant breast cancer. Citation Format: Anil Yadav, Lu Jin, Robert Clarke, Surojeet Sengupta. Adenylosuccinate lyase is essential for proliferation and mitochondrial function of endocrine therapy resistant breast cancer cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-23-08.

5-O-Acetylpinostrobin derivatives inhibit estrogen alpha and progesterone receptors through a molecular docking approach

Background: Among all cancers, breast cancer accounts for 11.7% of new cases and 6.9% of deaths worldwide. This is driven by increased estrogen receptor alpha (ERα) and progesterone receptor (PgR) expression. Many breast cancer drugs cause various side effects. Modifying the structure of pinostrobin by adding acyl groups to obtain 5-O-acetylpinostrobin derivatives can increase its activity and selectivity. Objective: This study aimed to predict the interaction of 5-O-acetylpinostrobin derivatives with ERα and PgR. Method: A molecular docking approach using AutodockTool. The Protein Data Bank (PDB) was used to obtain ID 3ERT (ERα) and 2W8Y (PgR). Result: The analysis showed the value of free energy binding (ΔG) to ERα with a range of -8.58 to -5.76 kcal/mol and an inhibition concentration (Ki) of 0.51 to 59.91 μM. PgR had ΔG values of -12.37 to -8.30 kcal/mol and Ki of 0.86 to 830.64 nM. Conclusion: The study showed that 5-O-4-(dimethylamino)benzoylpinostrobin, 5-O-cyclohexancarbonylpinostrobin, 5-O-2-phenylacetylpinostrobin, 5-O-3-phenylpropanoylpinostrobin, and 5-O-cyclobutanecarbonylpinostrobin have the potential to be synthesised and serve as the basis for the development of new anticancer compounds that inhibit ERα and PgR in breast cancer.

Estrogen receptors alpha and beta expression in different canine cancer types with an emphasis on hematopoietic malignancies.

Estrogen receptors (ERs) are located in both healthy and neoplastic tissues. The type of estrogen receptor expressed varies depending on its location, tumor type, and species. Estrogen action is mediated by binding to ER and activating the transcriptional and signaling processes that result in the control of gene expression. There are two main types of estrogen receptors: ER alpha (ERα) and ER beta (ERβ). Both receptors are functionally different, they may act antagonistically and are distributed in different tissues but their structure is similar - as they are composed of 5 different domains: A/B, C, D, E, and F. The signaling pathway and hence regulation of the gene expression by ERs is a complex and multifactorial process that involves both genomic and nongenomic actions. In the human reproductive tract, both ERα and β are present, with predominant expression of ERβ, while there are no satisfactory data distinguishing the type of ERs expressed in the canine reproductive tract. In mammary gland neoplasia, a decreased or lacking ERα expression in humans is associated with a poorer prognosis. This is similar to dogs, where higher ERα expression intensity was noted in benign tumors than in carcinomas. In human hematopoietic malignancies, ERβ is a predominant receptor. Selective and non-selective ERβ agonists have an antiproliferative and pro-apoptotic effect on human lymphoma cell lines and may be effective in the therapy of ERβ positive lymphomas and leukemias. In canine lymphoma tissues, none or only marginal expression of ERs was detected over the decades. Considering available data, we conducted preliminary studies proving that, in contrast to humans, the dominant ER expressed in canine hematopoietic tumors is ERα.

The prognostic value of MEK pathway-associated estrogen receptor signaling activity for female cancers.

Other than for breast cancer, endocrine therapy has not been highly effective for gynecologic cancers. Endocrine therapy resistance in estrogen receptor positive gynecologic cancers is still poorly understood. In this retrospective study, we examined the estrogen receptor (ER) signaling pathway activities of breast, ovarian, endometrial, and cervical cancers to identify those that may predict endocrine therapy responsiveness. Clinical and genomic data of women with breast and gynecological cancers were downloaded from cBioPortal for Cancer Genomics. Estrogen receptor alpha (ESR1) expression level and sample-level pathway enrichment scores (EERES) were calculated to classify patients into four groups (low/high ESR1 and low/high EERES). Correlation between ESR1/EERES score and survival was further validated with RNAseq data from low-grade serous ovarian cancer. Pathway analyses were performed among different ESR1/EERES groups to identify genes that correlate with endocrine resistance, which are validated using Cancer Cell Line Encyclopedia gene expression and Genomics of Drug Sensitivity in Cancer data. We identified a novel combined prognostic value of ESR1 expression and the corresponding estrogen response signaling (EERES score) for breast cancer. The combined prognostic value (ESR1/EERES) may be applicable to other gynecologic cancers. More importantly, we discovered that ER signaling can cross-regulate MEK pathway activation. We identified downstream genes in the MEK pathway (EPHA2, INAVA, MALL, MPZL2, PCDH1, and TNFRSF21) that are potential endocrine therapy response biomarkers. This study demonstrated that targeting both the ER and the ER signaling activity related MEK pathway may aid the development of endocrine therapy strategies for personalized medicine.

Abstract 6279: Estrogen signaling in low-grade serous ovarian carcinoma

Abstract High level of estrogen in the blood of women has been linked to the progression and possibly development of ovarian cancer. Almost all low-grade serous ovarian cancer (LGSOC) expresses estrogen receptor alpha (ERα protein encoded by the gene ESR1) and develops during reproductive age of women. However, recent studies suggested that a higher expression of ERα correlates with better survival. In a phase II clinical trial, hormonal therapies have been shown to be associated with a clinical benefit rate of 61% for recurrent ER-positive LGSOC patients. The study also indicated that women with recurrent LGSOC who received hormonal therapies had a significantly longer progression-free survival but not overall survival. Endocrine therapies have proven to be effective in treating breast cancer. Unfortunately, in ovarian cancer clinical trials (GOG0281 and PARAGON), these treatments have not achieved comparable results, with an objective response rate of only approximately 14%. To understand the ESR1 regulation in LGSOC, we have performed RNAseq and ChIPseq analyses of LGSOC tumor tissues. We also forced over-expression of ESR1 in LGSOC cell lines. Using RNAseq data, we aligned the sequencing reads to all the known ESR1 transcript variants. We found that ESR1 transcript variant 1, 2, 3 and X11 were the major transcripts expressed. Variants 1, 2 and 3 encode the regular 66 kDa ESR1 protein, while the X11 variant encodes a 52 kDa ESR1 protein. Both 66 kDa and 52 kDa ESR1 proteins were also detected in LGSOC tumor tissues by western blots. To further explore the function of ESR1 66kDa in LGSOC, we over-expressed ESR1 variant 1 in two LGSOC cell lines (HOC-7 and HCC5075) by transfecting with an expression plasmid. Total proteins were extracted from the mock control and transfected cells for functional proteomic analysis by reverse phase protein arrays (RPPA). From the RPPA data, overexpressing ESR1 in LGSOC cell lines suppressed DNA repair pathways but activated cell cycle and mitosis pathways. To further delineate the ESR1 DNA binding sites in LGSOC, we performed ChIPseq analysis of these tumor samples as well as two ovarian cancer cell lines that express ESR1 protein. Our results demonstrated that ESR1 regulated “cistromes” in ER positive ovarian carcinoma is very different from that in ER positive breast cancer as much less ESR1 binding sites were found in LGSOC. There are ESR1 binding sites common to both types of cancers, but we found quite a few unique ESR1 binding sites. We are trying to integrate the ChIPseq and RNAseq data and hopefully identify, for the first time, an ovarian cancer specific ERα cistrome. ER expression may not always correlate with activation of ESR1 signaling pathways, which may be one of the reasons underlying endocrine therapy resistance in ovarian cancer. The results of an integrated analyses will also give us insight on the management of ER positive LGSOC by identifying new genetic targets that may be used in combination with endocrine therapy. Citation Format: Yvonne TM Tsang, Chun Wai Oscar Ng, David Gershenson, K-Kwok wong. Estrogen signaling in low-grade serous ovarian carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6279.

Abstract 6286: Metabolic abnormalities are early predictors of liver metastasis in patients with ER+ breast tumors

Abstract Approximately 70% of human breast cancers express estrogen receptor alpha (ERα), providing a potential for targeted endocrine therapy for patients. Unfortunately, 30-40% of ER+ patients still experience recurrence and metastasis, with a 5-year relative overall survival rate of just 24% for patients with metastatic disease. In our preliminary analysis of the data from a large cohort of ER+ MBC patients, liver metastases were associated with reduced overall survival compared to other sites, while on the standard of care estrogen receptor antagonist, Fulvestrant (Fulv). This supports data from previous clinical trials showing that patients with liver metastases are less responsive to estrogen receptor alpha (ERα) targeting endocrine therapies compared to patients with bone or lung metastases. However, the factors underlying site-specific responses of MBC to ER antagonists are unknown. In this study, we investigated the concept that response of liver metastatic tumors is impacted by systemic glucose metabolism and the presence of liver metastatic tumors in turn will affect glucose homeostasis in the body. In our preliminary studies, metastatic liver tumors upregulated expression of enzymes that increased glycogen deposition in tumor cells in response to Fulv. Further analysis showed that a ketogenic diet restored Fulv response of metastatic liver tumors. Based on these results, we investigated if there was a relationship between metastatic site and response to endocrine therapy and if the metabolic status related to glucose homeostasis impacts metastatic disease response. We also searched if glucose homeostasis abnormalities can be indicators of liver metastasis. We obtained electronic health records from 192 patients with stage IV estrogen receptor positive breast cancer and analyzed glucose metabolism and liver panel markers including ALT, AST and ALP. Our results showed that more than 85% of patients with liver metastases have another accompanying metastasis and these patients are at a higher risk of diabetes diagnosis compared to other metastatic site patients. A higher % of patients with liver metastasis were deceased. We also observed increased levels of ALT, AST and ALP with liver metastasis and our preliminary analysis indicates that these blood biomarkers along with metabolic disease status (diabetes, hypertension, lipidemia) are good predictors of liver metastasis. Detecting early changes in markers of glucose metabolism may provide an easy diagnostic tool for early detection of liver metastases as well as assessment of treatment response. This may lead to accurate adjustment of treatment choices with improved outcome of patients with liver metastases from breast cancer. Citation Format: Ayca Nazli Mogol, Mahima Goel, Audrey Lam, Debapriya Dutta, Betsy Barnick, Maria Grosse Perdekamp, Zeynep Madak Erdogan. Metabolic abnormalities are early predictors of liver metastasis in patients with ER+ breast tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6286.

Investigating the effect of hesperetin on estrogen receptor alpha (ERα) expression, phosphorylation and activity in MCF-7 cells

PurposeThe most common malignancy among women worldwide is breast cancer. The estrogen receptor plays a vital role in this cancer. One of the most well-known mechanisms that affects the activity of this receptor is its phosphorylation by protein kinase pathways. Hesperetin, a flavonoid abundant in citrus species such as lemons, grapefruits, and oranges, is the aglycone form of hesperidin. It has undergone thorough evaluation for its potential anti-cancer properties, particularly in the context of breast cancer. Studies have shown that hesperetin has an effect on intracellular kinase pathways. The aim of this study was to investigate the effect of hesperetin on the expression, phosphorylation and activity of estrogen receptor alpha (ERα) in MCF-7 breast cancer cell line. Study design and methodsMCF-7 cells were cultured in RPMI-1640 phenol red-free medium supplemented with charcoal-stripped FBS and treated with hesperetin. The MTT method was used to evaluate cell survival. The levels of the ERα protein and its phosphorylated form (Ser118) were determined via western blotting. A luciferase reporter vector was used to evaluate ERE activity. ResultsThe results of this study indicated that hesperetin reduced the survival of MCF-7 cells in a dose-dependent manner. The expression and phosphorylation (at Ser118) of the ERα significantly increased and decreased, respectively, in the groups treated with hesperetin. Hesperetin increased the activity of the ERα in the absence of E2, although these differences were not statistically significant. Conversely, in the presence of E2, hesperetin caused a significant decrease in receptor activity. ConclusionBased on the results of this study, it can be concluded that hesperetin has a significant effect on ERα expression, phosphorylation and activity.

Chrysin’s dose-dependent effects on steroidogenesis in female BALB/c mice: In vivo study of adrenal, ovarian, and uterine hormone regulation

Background: Chrysin is known for its pharmacological effects and structural resemblance to estrogen. The study explores the impact of chrysin on steroidogenesis focusing on adrenal and ovarian steroidogenic enzymes. Materials and methods: Thirty female BALB/c mice were divided into three groups: a control group and two chrysin-treated groups (50 mg and 100 mg). Gene expression of key steroidogenic enzymes was assessed in adrenal glands and ovaries using RT-qPCR. Uterine expression of estrogen receptor alpha (ERα) was also examined. Histological analysis of adrenal glands and ovaries was performed. Results: High-dose chrysin downregulated CYP17A1 expression in adrenal glands compared to control and low-dose groups. In contrast, 3β-HSD was significantly downregulated in the high-dose group. In ovaries, high dose chrysin reduced aromatase expression. Conclusion: Our findings revealed that chrysin’s impact on steroidogenesis is dose-dependent. By downregulating CYP17A1 in adrenal glands, potentially affecting androgen and estrogen synthesis, and enhancing aromatase expression in ovaries at lower doses.

Phloretin Inhibits the Proliferation of Breast Cancer Cells Through the Down-regulation of Estrogen Receptor α.

Phloretin is a natural flavonoid compound found in some plants, such as apples and pears, as well as in the bark of apple trees. Phloretin has been shown to have inhibitory effects on glucose transporters in cells and can potentially inhibit the growth of cancer cells. However, the mechanism by which phloretin regulates the expression of estrogen receptor alpha (ERα), a key transcription factor in breast cancer, is still unclear. This study investigated how phloretin affects the growth of ERα positive human breast cancer cells. The growth of breast cancer cell lines, including MCF7 and T47D, was examined using cell proliferation and colony formation assays. Western blotting and semi-quantitative RT-PCR were used to examine protein and mRNA levels, respectively. Localization of cellular proteins was analyzed using subcellular fractionation. Transient transfection and reported gene assays were used to elucidate the impact of phloretin on cell proliferation and ERα transactivation. Phloretin decreased ERα expression at the mRNA and protein levels in MCF7 and T47D cells. It also inhibited the binding of ERα to the estrogen response element present in the promoter of target genes. Moreover, treatment with phloretin inhibited the expression of cyclin D1 and breast cancer marker gene pS2, which are known ERα target genes. Consequently, it inhibited the growth of ERα-positive human breast cancer cells. Furthermore, inhibition of breast cancer growth by phloretin was found to be mediated through both the ERα and ERK1/ERK2 pathways. Phloretin, a dihydrochalcone extracted from natural sources, exhibits the ability to regulate ERα function and suppress breast cancer cell proliferation.

Abstract A076: The role of PARP-1-mediated FoxA1 ADP-ribosylation in breast cancer biology

Abstract Breast cancer is the most common cancer diagnosed in women. At the time of diagnosis, approximately 70% of breast cancers express Estrogen Receptor alpha (ERα), a key signature of luminal subtype tumors. Equally important in these cases is the expression of FoxA1, a subtype-specific transcription factor (TF) essential for ERα-mediated cell proliferation. FoxA1 is a key pioneer TF that assists ERα with the assembly of enhancers and the transcription of estrogen (E2)-regulated target genes. Together, the FoxA1-ERα axis is a major driver of cancer cell growth. Our recently published work implicates poly(ADP-ribose) polymerase 1 (PARP-1) and ADP-ribosylation (ADPRylation) in the regulation of E2-dependent transcriptional responses in ERα+ breast cancer cells. To determine the underlying mechanisms, we identified FoxA1 as a substrate of PARP-1-mediated ADPRylation. We hypothesize that (1) PARP-1 elicits its effects on E2 signaling and ERα enhancer function, in part, by ADPRylating FoxA1 at specific residues and (2) Loss of these regulatory ADPRylation events alters FoxA1 activity, which in turn can alter the assembly of ERα enhancers and transform the breast cancer cell transcriptome. Indeed, the sites of FoxA1 ADPRylation are recurrently mutated in breast cancers and are highly enriched in metastatic cases. Using an integrated set of biochemical, molecular, cell based, genomic and proteomic approaches, we have validated the ADPRylation of FoxA1 by PARP-1 in vitro and in vivo. We selected two FoxA1 ADPRylation sites, D226 and E255, for further analysis due to their positions in a mutation ‘hot spot’ region corresponding to the C-terminal forkhead DNA-binding domain. Mutation of these sites blocks FoxA1 ADPRylation and enhances cell proliferation in MCF-7 human breast cancer cells. Additionally, preliminary ChIP-seq analysis indicates that the binding of both ERα and FoxA1 are globally reduced at ERα enhancers in MCF-7 cells expressing the FoxA1 ADPRylation site mutants compared to wild-type but may also increase both at selected enhancers. While there is a global reduction in mutant FoxA1 binding near the canonical estrogen-regulated genes, interestingly, we observe an overall enhanced binding of FoxA1 D226N compared to wild-type outside of this canonical program. Collectively, these studies will (1) reveal new molecular endpoints modulated by PARP-1, providing new insights about the use of PARPi to treat ERα+ breast cancers, and (2) suggest new therapeutic strategies to disrupt the aberrant signaling pathways associated with mutant FoxA1 luminal breast cancers, and more importantly metastatic cases, which is of utmost clinical significance. Citation Format: Cristel V. Camacho, Aishwarya Sundaresan, Tulip Nandu, W. Lee Kraus. The role of PARP-1-mediated FoxA1 ADP-ribosylation in breast cancer biology [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Breast Cancer Research; 2023 Oct 19-22; San Diego, California. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_1):Abstract nr A076.

Dietary restriction-induced alterations on estrogen receptor alpha expression in regulating fertility in male Coturnix coturnix japonica: Relevance of Withania somnifera in modulation of inflammation and oxidative stress in testis.

Reproductive performance of animals gets affected by nutritional restrictions which act as potential stressors leading to hormonal imbalance and testicular inflammation, the major causes of infertility. Withania somnifera (WS), well-known traditional medicinal plant, has been used as antistress and infertility treatment. Therefore, the present study looks into the ameliorative effects of WS on the reproductive and immune system of male Coturnix coturnix japonica in stressed conditions like water and food restriction focussing on the modulation in estrogen receptor alpha (ERα). Biochemical estimations for oxidative stress, histological alterations, immuno-fluorescent localization of ERα, interleukin (IL)-1β, IL-4, and interferon gamma (IFN-γ) in testicular cells were performed. Nutritional restriction declines endogenous estradiol, ERα in testicular cells while it elevates corticosterone leading to oxidative stress in testis thereby reducing fertility by decrease in sperm. Results indicate significant reversal in all the parameters after the administration of WS by improving testicular cell morphology, increased superoxide and catalase activity thus reducing oxidative stress. WS increases spermatogenesis and enhances expression of ERα in testicular cells in quail. Further, WS increases IL-4, decreases IL-1β and IFN-γ expression in testis, thereby improving immune profile contrary to stressed conditions. WS stimulates HPG-axis even after stress resulting in increased endogenous estradiol which stimulates the expression of ERα in testis; increases sperm count and immunity thereby improving the reproductive performance. WS may be the best therapy against nutritional-restriction stress induced reproductive toxicity by reducing oxidative stress mediated inflammatory response via increased testicular expression of ERα in quail.

CRISPR-Cas9 knockdown of ESR1 in preoptic GABA-kisspeptin neurons suppresses the preovulatory surge and estrous cycles in female mice.

Evidence suggests that estradiol-sensing preoptic area GABA neurons are involved in the preovulatory surge mechanism necessary for ovulation. In vivo CRISPR-Cas9 editing was used to achieve a 60-70% knockdown in estrogen receptor alpha (ESR1) expression by GABA neurons located within the regions of the rostral periventricular area of the third ventricle (RP3V) and medial preoptic nuclei (MPN) in adult female mice. Mice exhibited variable reproductive phenotypes with the only significant finding being mice with bilateral ESR1 deletion in RP3V GABA neurons having reduced cFos expression in gonadotropin-releasing hormone (GnRH) neurons at the time of the surge. One sub-population of RP3V GABA neurons expresses kisspeptin. Re-grouping ESR1-edited mice on the basis of their RP3V kisspeptin expression revealed a highly consistent phenotype; mice with a near-complete loss of kisspeptin immunoreactivity displayed constant estrus and failed to exhibit surge activation but retained pulsatile luteinizing hormone (LH) secretion. These observations demonstrate that ESR1-expressing GABA-kisspeptin neurons in the RP3V are essential for the murine preovulatory LH surge mechanism.

152 Influence of diarylheptanoid supplementation from Curcuma comosa extract on Ki67 and estrogen receptor alpha expression in goat ovaries

152 Influence of diarylheptanoid supplementation from Curcuma comosa extract on Ki67 and estrogen receptor alpha expression in goat ovaries

Global cerebral ischemia in adult female rats interrupts estrous cyclicity and induces lasting changes in hypothalamic-pituitary-gonadal axis signaling peptides

Persistent post-ischemic alterations to the hypothalamic–pituitary–adrenal (HPA) axis occur following global cerebral ischemia (GCI) in rodents. However, similar effects on hypothalamic-pituitary–gonadal (HPG) axis activation remain to be determined. Therefore, this study evaluated the effects of GCI in adult female rats (via four-vessel occlusion) on the regularity of the estrous cycle for 24-days post ischemia. A second objective aimed to assess persistent alterations of HPG axis activation through determination of the expression of estrogen receptor alpha (ERα), kisspeptin (Kiss1), and gonadotropin-inhibitory hormone (GnIH/RFamide-related peptide; RFRP3) in the medial preoptic area (POA), arcuate nucleus (ARC), dorsomedial nucleus (DMH) of the hypothalamus, and CA1 of the hippocampus 25 days post ischemia. Expression of glucocorticoid receptors (GR) in the paraventricular nucleus of the hypothalamus (PVN) and CA1 served as a proxy of altered HPA axis activation. Our findings demonstrated interruption of the estrous cycle in 87.5 % of ischemic rats, marked by persistent diestrus, lasting on average 11.86 days. Moreover, compared to sham-operated controls, ischemic female rats showed reduced Kiss1 expression in the hypothalamic ARC and POA, concomitant with elevated ERα in the ARC and increased GnIH in the DMH and CA1. Reduced GR expression in the CA1 was associated with increased GR-immunoreactivity in the PVN, indicative of lasting dysregulation of HPA axis activation. Together, these findings demonstrate GCI disruption of female rats’ estrous cycle over multiple days, with a lasting impact on HPG axis regulators within the reproductive axis.

Comparative analysis of gonadal hormone receptor expression in the postnatal house mouse, meadow vole, and prairie vole brain

The socially monogamous prairie vole (Microtus ochrogaster) and promiscuous meadow vole (Microtus pennsylvanicus) are closely related, but only prairie voles display long-lasting pair bonds, biparental care, and selective aggression towards unfamiliar individuals after pair bonding. These social behaviors in mammals are largely mediated by steroid hormone signaling in the social behavior network (SBN) of the brain. Hormone receptors are reproducible markers of sex differences that can provide more information than anatomy alone and can even be at odds with anatomical dimorphisms. We reasoned that behaviors associated with social monogamy in prairie voles may emerge in part from unique expression patterns of steroid hormone receptors in this species, and that these expression patterns would be more similar across males and females in prairie than in meadow voles or the laboratory mouse. To obtain insight into steroid hormone signaling in the developing prairie vole brain, we assessed expression of estrogen receptor alpha (Esr1), estrogen receptor beta (Esr2), and androgen receptor (Ar) within the SBN, using in situ hybridization at postnatal day 14 in mice, meadow, and prairie voles. We found species-specific patterns of hormone receptor expression in the hippocampus and ventromedial hypothalamus, as well as species differences in the sex bias of these markers in the principal nucleus of the bed nucleus of the stria terminalis. These findings suggest the observed differences in gonadal hormone receptor expression may underlie species differences in the display of social behaviors.

Prediction models for hormone receptor status in female breast cancer do not extend to males: further evidence of sex-based disparity in breast cancer

Breast cancer prognosis and management for both men and women are reliant upon estrogen receptor alpha (ERα) and progesterone receptor (PR) expression to inform therapy. Previous studies have shown that there are sex-specific binding characteristics of ERα and PR in breast cancer and, counterintuitively, ERα expression is more common in male than female breast cancer. We hypothesized that these differences could have morphological manifestations that are undetectable to human observers but could be elucidated computationally. To investigate this, we trained attention-based multiple instance learning prediction models for ERα and PR using H&E-stained images of female breast cancer from the Cancer Genome Atlas (TCGA) (n = 1085) and deployed them on external female (n = 192) and male breast cancer images (n = 245). Both targets were predicted in the internal (AUROC for ERα prediction: 0.86 ± 0.02, p < 0.001; AUROC for PR prediction = 0.76 ± 0.03, p < 0.001) and external female cohorts (AUROC for ERα prediction: 0.78 ± 0.03, p < 0.001; AUROC for PR prediction = 0.80 ± 0.04, p < 0.001) but not the male cohort (AUROC for ERα prediction: 0.66 ± 0.14, p = 0.43; AUROC for PR prediction = 0.63 ± 0.04, p = 0.05). This suggests that subtle morphological differences invisible upon visual inspection may exist between the sexes, supporting previous immunohistochemical, genomic, and transcriptomic analyses.

Lactobacillus plantarum CCFM1180 attenuates obesity induced by estrogen deficiency by activating estrogen receptor alpha in abdominal adipose tissue and regulating gut microbiota-derived metabolitesestrogen

Lipid metabolism disorders commonly occur during menopause. Estrogen deficiency has been shown to lead to excessive energy intake and abnormal lipid metabolism in ovariectomized rats, resulting in obesity. Probiotics exhibit anti-obesity properties, and their underlying mechanism has been widely reported. In this study, we demonstrated the metabolic benefits of Lactobacillus plantarum CCFM1180 in suppressing appetite, controlling body weight, correcting obesity-induced abnormalities, enhancing liver lipid metabolism, and protecting liver function in estrogen-deficient rats. The mechanisms associated with the anti-obesity and anti-dyslipidemia effects of CCFM1180 on estrogen-deficient rats were clarified. The results showed that CCFM1180 dramatically reduced food intake by activating the expression of estrogen receptor alpha (ERα) and increasing the level of leptin in abdominal adipose tissue. These changes, combined with the increased butyrate concentration and recovered bile acid structure, helped enhance lipid metabolism. Additionally, CCFM1180 treatment was found to be safer than exogenous estrogen supplementation. Thus, L. plantarum CCFM1180 could be considered a new therapeutic strategy for preventing and alleviating menopausal lipid abnormalities.

THU575 The Canonical Wnt/β-catenin Pathway Is Not Involved In Estrogen-induced Skeletal Muscle Fibrosis In A Mouse Model Of Inguinal Hernia

Abstract Disclosure: T. You: None. H. Zhao: None. T. Potluri: None. P. Yin: None. S.E. Bulun: None. Inguinal hernias affect up to 27% of elderly men, with approximately 800,000 inguinal hernia repair surgeries performed annually. While these procedures are often effective, a significant subset of hernias are refractory to treatment, resulting in high mortality, high recurrence, and chronic pain. Until recently, little research has been done examining the molecular mechanisms that drive hernia-associated lower abdominal wall weakening. Our lab previously created a transgenic mouse model expressing the human aromatase gene (Aromhum) and showed that male Aromhum mice produced high levels of estrogen in the lower abdominal muscle (LAM) tissue, leading to extensive LAM fibrosis, muscle atrophy, and hernia formation. Single-cell analysis of fibrotic LAM tissue in these mice showed high expression of estrogen receptor alpha (ERα) in LAM fibroblasts as well as upregulation of Wnt signaling pathways in these ERα-positive fibroblasts. The canonical Wnt/β-catenin signaling pathway has been implicated in fibroblast activation and fibrosis in multiple organs, including the lung, heart, and skin. Thus, we hypothesized that canonical Wnt/β-catenin signaling acts as a downstream mediator of ERα to cause LAM fibroblast activation, tissue fibrosis, and hernia. To test our hypothesis, we cultured primary ERα-positive LAM fibroblasts from Aromhum mice in the presence of estrogen with or without siRNA knockdown (KD) of β-catenin. However, KD of β-catenin under these conditions did not alter fibroblast proliferation as measured by EdU assay, nor did it alter expression of genes involved in fibroblast activation or extracellular matrix formation. Furthermore, administration of LGK974, a Wnt signaling inhibitor, in male Aromhum mice did not prevent hernia development, decrease hernia size, or decrease the extent of LAM fibrosis and muscle atrophy. Thus, we concluded that the canonical Wnt/β-catenin signaling pathway does not serve as a downstream mediator of estrogen-induced skeletal muscle fibrosis in our Aromhum mouse model of inguinal hernia. Further studies are needed to evaluate the role of Wnt/β-catenin signaling in other inguinal hernia models or in humans. Presentation Date: Thursday, June 15, 2023

SAT421 Near Term Cardiometabolic Outcomes of Testosterone Therapy In Transgender Boys And Men

Abstract Disclosure: J. Dey: None. C. O’neill: None. C. Bingham-Tyson: None. M.E. Widlansky: None. S. Cabrera: None. Background: Medical therapy for transgender males may include GnRH agonists and gender affirming testosterone (T) hormone therapy (GAHT). Given the clear sexual dimorphism in cardiometabolic disease risk, it is reasonable to assume GAHT affects the cardiometabolic health of transmales. In cisgender women, hypoestrogenism reduces vasculo-protective E2-mediated estrogen receptor alpha (ERα) expression and increases susceptibility to future vascular complications. Whether similar changes occur in transmales on GAHT remains poorly studied. To our knowledge, no study has addressed possible mechanisms by which GAHT affects vascular physiology in transmales. Here, we present study procedures and preliminary results of an ongoing 2-site trial that aims to examine the impact of GAHT on cardiometabolic health in transmales. The primary outcome is the change in brachial artery flow-mediated dilation (FMD%), an in vivo measure of human vascular endothelial health, after 1-yr of GAHT. We hypothesize that, in transmales with completed E2-driven puberty, GAHT will induce a regression of vascular endothelial function towards that of cismales by suppressing circulating E2 and vascular ERα and that lesser regression will be seen in transmales initiating GAHT before completion of full E2-mediated pubertal progression. Methods: This is a longitudinal observational study of transmales aged 12-30 yrs over the first year of GAHT, with visits at baseline (BL), 6-mo, and 1-yr, matched by age and puberty to healthy cisfemales and cismales with endogenous sex hormone production. To detect a significant relative change in FMD% at 1-yr from BL, 80 participants are needed to enroll (40 transmales, 20 cisfemales, 20 cismales) and 64 to complete all visits. Vascular function is assessed by FMD% and circulating markers of endothelial activation. Metabolism/inflammation is assessed by fasting lipids, glucose, insulin, leptin, and serum cytokines. Body composition is assessed by DXA. Results: To date, 34 participants (20 transmales, 5 cisfemales, and 9 cismales) have had BL visits and 13 have completed 6-mo visits. At BL, trans and cis participants are matched for age and puberty and have similar vascular function, body composition, and metabolism. While the small number of participants with BL and 6-mo data precludes statistical analyses, initial findings have not identified significant changes in vascular function, metabolism, or body composition in transmales on GAHT. The study is ongoing. Conclusion:This study will be completed in 2024 and should inform novel mechanisms by which GAHT affects vascular function and cardiometabolic health relative to cisgender controls. Completion of the cohort will allow for proper analyses, powered to detect a change in FMD% after 1-yr of GAHT. On-going work includes retention of a well-matched, but pubertal stage diverse, cohort. Presentation: Saturday, June 17, 2023

Effects of bisphenol A on murine salivary glands and human tumor cell lines

Bisphenol A (BPA) is an endocrine-disrupting chemical with a potential role in endocrine cancers. However, the effects of BPA on the salivary glands have been barely explored. We investigated the impact of in vivo sub-chronic exposure to BPA and its in vitro effects on human salivary gland mucoepidermoid carcinoma cell lines. Male and female mice were exposed to BPA (30 mg/kg/day). Sublingual and submandibular salivary glands from an estrogen-deficiency model were also analyzed. BPA concentration in salivary glands was evaluated by gas chromatography coupled to ion trap mass spectrometry. Immunohistochemical analysis using anti-p63 and anti-α-SMA antibodies was performed on mouse salivary gland tissues. Gene expression of estrogen receptors alpha and beta, P63 and α-SMA was quantified in mouse salivary gland and/or mucoepidermoid (UM-HMC-1 and UM-HMC-3A) cell lines. Cell viability, p63 and Ki-67 immunostaining were evaluated in vitro. BPA disrupted the tissue architecture of the submandibular and sublingual glands, particularly in female mice, and increased the expression of estrogen receptors and p63, effects that were accompanied by significant BPA accumulation in these tissues. Conversely, ovariectomy slightly impacted BPA-induced morphological changes. In vitro, BPA did not affect the proliferation of neoplastic cells, but augmented the expression of p63 and estrogen receptors. The present data highlight a potential harmful effect of BPA on salivary gland tissues, particularly in female mice, and salivary gland tumor cells. Our findings suggest that estrogen-dependent pathways may orchestrate the effects of BPA in salivary glands.