ERα Levels Research Articles

Aptamer Proteolysis-Targeting Chimeras (PROTACs): A Novel Strategy to Combat Drug Resistance in Estrogen Receptor α-Positive Breast Cancer.

Breast cancer with positive expression of estrogen receptor α (ERα+) accounts for 70% of breast cancer cases, whose predominant treatment is currently endocrine therapy. The main strategy of endocrine therapy for ERα+ breast cancer is to inhibit the ERα signaling pathway and downregulate ERα levels, which often results in mutations in the ligand-binding domain (LBD) of ERα, leading to significant resistance to subsequent treatment in patients. To combat drug resistance, we first proposed a novel aptamer PROTAC strategy through specifically targeted degradation of ERα via targeting the DNA-binding domain (DBD) of ERα. We proved that this strategy is capable of targeting ERα for degradation through ubiquitination, leading to the inhibition of proliferation in ERα+ breast cancer cells and tamoxifen-resistant breast cancer cells. Furthermore, we investigated the mechanisms involved in overcoming resistance. By circumventing drug resistance associated with LBD mutations in ERα, our approach provides a promising avenue for the discovery of new therapeutic agents.

Exogenous Insulin Effect on the Initiation of Breast Cancer in Type 2 Diabetes Mellitus Patients

Background: Growing evidence has indicated that women with type 2 diabetes mellitus are at an increased risk of developing breast cancer. However, as a major adjuvant treatment, the influence of hormone therapy such as exogenous insulin on type 2 diabetes mellitus in primary breast-cancer remains controversial. Objective: To explore the relationship between different types of hypoglycemic medications for diabetes and the factors that may contribute to the initiation of breast cancer. Methods: The study included 80 blood samples taken from 80 females recruited from Ibn Al-Bitar Center for Cardiac Surgery Hospital in Baghdad, Iraq, between November 2022 and February 2023. They were within the age range of 40 to 70 years. They were divided into three groups according to the treatment strategy and duration of disease as follows: Group 1: (20) patients who take insulin only, Group 2: (20) patients who take metformin with insulin, and G 3: (40) patients on metformin only for less than one year. An enzymatic oxidation technique was used to test the following biochemical parameters for all research groups: Total cholesterol, triglycerides, fasting blood glucose, and high-density lipoprotein cholesterol. Using the Friedewald formula, the very low-density lipoprotein cholesterol and low-density lipoprotein cholesterol were determined. Using an enzymatic process, Insulin levels and Insulin like growth factor-1(IGF-1), Estrogen receptor alpha (ERα) levels, and breast cancer susceptibility protein 1 (BRCA1) were measured with an enzyme-linked immunosorbent assay (ELISA). Glycated hemoglobin (HbA1c) level was measured with a sandwich immunodetection method. Finally, The Homeostasis Model Assessment for insulin resistance (HOMA-IR) was calculated according to the specific formula. Results: The values for HbA1C%, FBS, and lipid profile showed non-significant differences when compared between study groups. While BRCA-1, estrogen receptor alpha (ERα), insulin, insulin growth factor IGF-1, and HOMA IR All showed significant differences among all groups. Conclusion: Taking metformin only for less than one year seemed to contribute to higher levels of BRCA-1.

In Vivo Chemosuppressive Effects of Kolaviron on 7,12-Dimethylbenzanthracene-Induced Mammary Lesions are Associated with Changes in Levels of Estrogen Receptor-α, CYP 1A1, Proinflammatory Cytokines, and Alterations to Metabolic Pathways Implicated in Mammary Carcinogenesis.

Garcinia kola is a medicinal food commonly consumed in Sub-Sahara Africa, for which Kolaviron (KV) is the active portion. As a follow-up to our earlier chemopreventive studies, we investigated the chemotherapeutic effects of KV on experimentally induced mammary carcinogenesis in female Wistar rats. Mammary carcinogenesis was induced using 80 mg/kg of 7,12-dimethylbenzanthracene (DMBA) administered by oral gavage. One hundred-fifty days post-DMBA induction, estrogen receptor-α (ER-α) levels were determined in the experimental rats before treatment with KV commenced. Treatment was done using 50, 100, and 200 mg/kg KV thrice a week for 4 weeks, after which the experiment was terminated. Significantly higher levels of estrogen receptor-α, CYP 1A1, malondialdehyde, formation of lobular neoplastic cells, epithelial hyperplasia, lymphocyte infiltration, and increased cytokine (interleukin-6 and tumor necrosis factor-α) activity were observed in DMBA-induced rats, which were attenuated in KV-treated rats. Tyrosine metabolism was exclusively enriched in DMBA-induced rats in contrast to KV-treated rats. Collectively, the results point to the chemotherapeutic potential of KV.

COPD-Like Phenotypes in TBC-Treated Mice Can be Effectively Alleviated via Estrogen Supplement.

Tris(2,3-dibromopropyl) isocyanurate (TBC), recognized as an endocrine disruptor, can cause inflammatory injury to the lung tissue of mice. To investigate the specific respiratory effects of TBC, male C57BL/6J mice were administered a daily dose of 20 mg/kg of TBC over 14 days. Postexposure, these mice developed chronic obstructive pulmonary disease (COPD)-like symptoms characterized by inflammatory lung damage and functional impairment. In light of the antiestrogenic properties of TBC, we administrated estradiol (E2) to investigate its potential protective role against TBC-induced damage and found that the coexposure of E2 notably mitigated the COPD-like phenotypes. Immunohistochemical analysis revealed that TBC exposure reduced estrogen receptor alpha (ERα) expression and increased nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) expression, while E2 treatment rebalanced the expression levels of ERα and NF-κB to their normative states. Our findings indicate that TBC, as an antiestrogenic agent, may contribute to the pathogenesis of COPD through an ERα-mediated inflammatory pathway, but that E2 treatment could reverse the impairment, providing a potentially promising remedial treatment. Given the lung status as a primary target of air pollution, the presence of antiestrogenic compounds like TBC in atmospheric particulates presents a significant concern, with the potential to exacerbate respiratory conditions such as COPD and pneumonia.

The GPR30 Receptor Is Involved in IL-6-Induced Metastatic Properties of MCF-7 Luminal Breast Cancer Cells.

Luminal breast cancer has a high incidence worldwide and poses a severe health threat. Estrogen receptor alpha (ER-α) is activated by 17β-estradiol (E2), and its overexpression promotes cancerous characteristics. Luminal breast cancer is an epithelial type; however, the cytokine IL-6, secreted by cells within the tumor microenvironment, stimulates the epithelial-to-mesenchymal transition (EMT) and promotes metastasis. Also, IL-6 decreases ER-α levels, favoring the tamoxifen (TMX) resistance development. However, genes under E2 regulation continue to be expressed even though this receptor is absent. GPR30 is an alternative E2 receptor present in both luminal and aggressive triple-negative breast cancer and is related to TMX resistance and cancer progression. The roles of GPR30 and IL-6 in metastasis have been individually established; however, their interplay remains unexplored. This study aims to elucidate the role of GPR30 in IL-6-induced metastatic properties of MCF-7 luminal breast cancer cells. Results showed that GPR30 contributes to the E2-induced MCF-7 proliferation because its inhibition with the antagonist G15 and the Pertussis toxin (PTX) reduced it. Besides, GPR30 upregulated vimentin and downregulated E-cadherin levels in MCF-7 and TMX-resistant (R-TMX) cells and is also involved in the IL-6-induced migration, invasion, and TMX resistance in MCF-7 cells. In addition, in MDA-MB-231 triple-negative cells, both basal and IL-6-induced metastatic properties were related to GPR30 activity. These results indicate that the GPR30 receptor regulates the EMT induced by IL-6 in breast cancer cells.

Biological characteristics related to treatment effects of the levonorgestrel-releasing intrauterine system on adenomyosis-associated dysmenorrhoea

Research questionTo investigate the correlations among the biological expression of steroid receptors, fibrosis levels in adenomyotic lesions, and the treatment effectiveness of the levonorgestrel-releasing intrauterine system (LNG-IUS) on alleviation of dysmenorrhea. DesignIn this retrospective cohort study, 125 women with adenomyosis who underwent hysterectomy were included. The tissue samples were collected from 41 patients who had been treated by the LNG-IUS prior to surgery and these patients were further categorized into an effective group (n = 18) and a failure group (n = 23) according to their self-reported relief from dysmenorrhea after 6-month treatment. The expression levels of estrogen receptor-α (ER-α), progesterone receptor (PR), and the extent of fibrosis levels in the adenomyotic lesions were measured by immunohistochemistry and Masson's trichrome staining respectively. ResultsPatients in the failure group demonstrated lower expression levels of ER-α and PR and more pronounced fibrosis in the stroma of adenomyotic lesions compared to those in the effective group. In the glandular epithelium of lesions, ER-α expression was significantly reduced in the failure group, whereas no notable difference in PR expression was observed. Notably, the staining intensity of ER-α in the stroma of the lesions was found to have the strongest positive correlation with the degree of symptom alleviation for dysmenorrhea (r=0.47) with an area under the curve of 0.894 for prediction. ConclusionsThe findings suggest that the reduced expressions of steroid receptors in adenomyotic lesions especially ER-α in the stroma were associated with an increased likelihood of treatment failure of LNG-IUS in alleviating dysmenorrhea.

Exploration and optimisation of structure-activity relationships of new triazole-based C-terminal Hsp90 inhibitors towards in vivo anticancer potency

The development of new anticancer agents is one of the most urgent topics in drug discovery. Inhibition of molecular chaperone Hsp90 stands out as an approach that affects various oncogenic proteins in different types of cancer. These proteins rely on Hsp90 to obtain their functional structure, and thus Hsp90 is indirectly involved in the pathophysiology of cancer. However, the most studied ATP-competitive inhibition of Hsp90 at the N-terminal domain has proven to be largely unsuccessful clinically. Therefore, research has shifted towards Hsp90 C-terminal domain (CTD) inhibitors, which are also the focus of this study. Our recent discovery of compound C has provided us with a starting point for exploring the structure-activity relationship and optimising this new class of triazole-based Hsp90 inhibitors. This investigation has ultimately led to a library of 33 analogues of C that have suitable physicochemical properties and several inhibit the growth of different cancer types in the low micromolar range. Inhibition of Hsp90 was confirmed by biophysical and cellular assays and the binding epitopes of selected inhibitors were studied by STD NMR. Furthermore, the most promising Hsp90 CTD inhibitor 5x was shown to induce apoptosis in breast cancer (MCF-7) and Ewing sarcoma (SK-N-MC) cells while inducing cause cell cycle arrest in MCF-7 cells. In MCF-7 cells, it caused a decrease in the levels of ERα and IGF1R, known Hsp90 client proteins. Finally, 5x was tested in zebrafish larvae xenografted with SK-N-MC tumour cells, where it limited tumour growth with no obvious adverse effects on normal zebrafish development.

IMMUNOFLUORESCENCE ANALYSIS OF ESTROGEN RECEPTORS ALPHA EXPRESSION IN NON-SMALL CELL LUNG CANCER TISSUE

Quantitative assessment of estrogen receptors alpha (ERα) expression was carried out in 115 samples of non-small cell lung cancer (NSCLC) by an immuno uorescent assay and ow cytometry. It has been shown that high level of ERα ≥20% predicts higher aggressiveness of NSCLC than at low level <20%: median survival at 78 mos of follow-up is increased by 1.5 times; the risk of death is reduced by almost 2.0 times (p = 0.04). Time to death was increased by an average of 18 mos in about 20% of patients with low ERα expression. The results validate informative value of immuno uorescence analysis and owcytometry for quantifying the ERα expression and substantiate the prospects of antiestrogen therapy as a new option for NSCLC treatment, in particular, by analogy with breast cancer - in a long-term adjuvant therapy in ERα+ NSCLC patients.

Degradation of estrogen receptor α induced by ionizing radiation contributes to senescence of ER+ breast cancer cells.

e12544 Background: According to the clinical and pathological characteristics, breast cancer is usually classified into estrogen receptor positive (ER+), human epidermal growth factor receptor 2 positive and triple negative. Among them, ER+ breast cancer accounts for more than two-thirds of total breast cancer. Nowadays, both ionizing radiation and endocrine therapy are used for the treatment of ER+ breast cancer. In our previous studies, it was found that significant cellular senescence and reduction of endogenous estradiol (E2) were induced by carbon ion or X-ray exposure in ER+ breast cancer cells. However, the underlying mechanism remains unclear. Methods: Two human ER+ breast cancer cell lines, MCF7 and T47D, were chosen to investigate the senescence-associated indications after 1-10 Gy of X-ray exposure. Since the elevated estrogen receptor α (ERα) is the most significant characteristic of ER+ breast cancer, the levels of ERα were detected by qRT-PCR and West Blotting analysis. In addition, MCF7 tumors were established in BALB/C nude mice and discerned using immunohistochemistry after local exposure of tumors to 2 Gy of X-rays. Results: It was confirmed that the cell survival decreased in a dose-dependent manner after 1-10 Gy of X-ray exposure in both cell lines. Increased p21 protein expression which was considered as a senescence biomarker and enhanced senescence-associated β-galactosidase activity were also observed after X-ray exposure. Meanwhile, distinct cell cycle arrest was induced by 2 Gy of X-rays in T47D cells or by 8 Gy of X-rays in MCF7 cells, implying that T47D cells were prone to enter senescence. Furthermore, both the mRNA levels and protein levels of ERα were significantly decreased at 24 hours in the two cell lines when the exposure dose was up to 4 Gy of X-rays. Reduction of glucocorticoid-regulated kinase 3 (SGK3), a transcriptional target for ERα, was also observed in both cell lines, in according with the reported SGK3-dependent survival mediated by ERα/E2 dimer in ER+ breast cancer cells. In vitro experiments, the results verified the ERα degradation and the proliferating inhibition indicated by suppression of Ki67 protein in MCF7 tumor after 2 Gy exposure. Conclusions: These findings reveal that the degradation of estrogen receptor α induced by ionizing radiation contributes to the senescence of ER+ breast cancer cells and thereby inhibits the tumor growth. The results provide a potential therapeutic strategy to enhance the radiosensitivity of ER+ breast cancer cells through regulations of ERα or ERα-regulated kinase SGK3 in radiotherapy.

Mechanistic insights into the parental co-exposure of T-2 toxin and epoxiconazole on the F1 generation of zebrafish (Danio rerio)

Mycotoxins and pesticides frequently coexist in agricultural commodities on a global scale. The potential transgenerational consequences induced by these substances pose a significant threat to human health. However, there is a lack of data concerning the effects of co-contamination by these chemicals in the F1 generation following parental exposure. This investigation delved into the mixture effects of T-2 toxin (T-2) and epoxiconazole (EPO) on the offspring of zebrafish (Danio rerio). The findings revealed that exposure across generations to a combination of T-2 and EPO resulted in toxicity in the larvae of the F1 generation. This was demonstrated by a significant increase in the levels or activities of malondialdehyde (MDA), thyroxine (T4), Caspase3, and cas9, along with a decrease in the levels of cyp19a, ERα, and ERβ. These outcomes suggested that cross-generational exposure to T-2 and EPO in D. rerio disrupted oxidative balance, induced cell apoptosis, and affected the endocrine system. Moreover, these effects were magnified when the F1 generation was continuously exposed to these compounds. Notably, these adverse effects could persist in subsequent generations without additional exposure. This study underscored the potential dangers associated with the simultaneous presence of T-2 and EPO on the development of fish offspring and the resulting environmental hazards to aquatic ecosystems. These findings emphasized the significant health risks posed by cross-generational exposure and highlighted the need for additional legislative measures to address these concerns.

17β-estradiol Inhibits Oxidative Stress-Induced Apoptosis in Endometrial Cancer Cells by Promoting FOXM1 Expression.

The steroid hormone 17β-estradiol (E2) has a significant impact on the development and progression of tumors. E2 stimulates tumor cell growth and metabolism, leading to an increase in reactive oxygen species (ROS) production. However, the rise in ROS levels is not sufficient to cause severe harm to cancer cells. and the mechanisms that regulate ROS are not well understood. Since FOXM1 plays a crucial role in the production of ROS, we aimed to investigate the impact of E2 on oxidative stress and the involvement of FOXM1 in the Ishikawa endometrial cancer cell line. Our research revealed that E2 controls the levels of ROS inside cells and safeguards them from apoptosis by promoting the expression of FOXM1. We observed a decrease in the expression of FOXM1 alongside an increase in oxidative damage. Moreover, cells demonstrated elevated levels of FOXM1 and ERα upon E2 treatment. Overall, our findings suggest that E2 prevents apoptosis induced by oxidative stress in endometrial cancer cells by encouraging the expression of FOXM1, potentially affecting ERα.

Abstract PO2-24-07: Investigation into potential Estrogen Receptor (ER)-mediated regulation of Phosphoserine Aminotransferase (PSAT1)

Abstract Breast cancer is one of the leading causes of death among women. Expression of different proteins, such as hormone receptors (HR), are used to classify different types of breast cancer (i.e., HR+BC or triple negative breast cancer (TNBC)). While activation of the estrogen receptor (ER) in HR+BC is known to regulate a vast number of downstream targets in promoting breast cancer, there may be additional ER-regulated processes that are still unknown. The serine synthetic pathway has been demonstrated to be crucial in the proliferation and survival of select subtypes of breast cancer and phosphoserine aminotransferase 1 (PSAT1) is a key regulatory step. Previous studies have demonstrated higher PSAT1 levels in cells lacking ER and we now show a negative correlation between ERα protein levels and PSAT1 transcripts in human patient samples. This indicates that ER may potentially regulate PSAT1 expression. To initially investigate this potential relationship, either WT or constitutively active mutant ERα was expressed in TNBC cells (MDA-MB-231), which have high endogenous PSAT1 expression and no ER. Immunoblot was used to verify ERα levels and to assess effects on PSAT1. We observed a qualitative trend in decreasing PSAT1 levels with re-expression of ERα in the TNBC cells. While the variabilities in these results preclude any conclusion of a ERα:PSAT1 regulatory axis, the lack of a quantifiable effect on PSAT1 levels is postulated to be due to the transient nature of ERα expression/suppression in these systems. A more profound effect would be expected under durable changes in ERα levels and is a focus on-going studies. Citation Format: Mary Sumlut, James Wittliff, Brian Clem. Investigation into potential Estrogen Receptor (ER)-mediated regulation of Phosphoserine Aminotransferase (PSAT1) [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 PO2-24-07.

Changes in ovarian tissue structure and distribution of oestrogen receptors in Huanghuai goats at different ages.

To observe developmental changes in the ovarian tissue structure and distribution characteristics of oestrogen receptors (ERs) in the ovaries of Huanghuai goats at different ages, we selected healthy Huanghuai goats ewes and divided them into five groups (i.e. 3-, 30-, 60-, 90- and 120-day-old groups), with 10 animals in each group. The serum was separated after blood collection through the jugular vein, and the contents of oestrogen (E) and progesterone (P) in the serum of Huanghuai goats at each age were determined. Three goats were randomly selected from each group and sacrificed after anaesthesia, and the ovarian tissue was quickly obtained and placed in 4% paraformaldehyde fixative to prepare the tissue sections. Using HE, oestrogen receptors were immunohistochemically stained and observed. These results showed many primordial follicles and occasional secondary follicles in the ovaries of 3-day-old Huanghuai goats. Ovarian reticular structures were observed in 30-day-old ovarian medulla, with occasional near-mature growing follicles. Mature follicles and corpus luteum were occasionally detected in 60-day-old ovarian cortex. The 90-120-day-old ovarian cortices contained growing and mature follicles, and the number of mature follicles and corpora lutea increased, implying a significant luteal involution period. The E and P contents in the 120-day-old group were significantly higher than those in the 3-, 30-, 60- and 90-day-old groups. The levels of ERα and ERβ in the 3- and 30-day-old groups were mainly distributed in the granulosa cells of ovarian reproductive epithelial cells, primordial follicles, atretic follicles, and primary and secondary follicles. The ERα and ERβ levels of the 60-, 90- and 120-day-old groups were also distributed in the granulosa cells and luteal cells of mature follicles, especially in the 120-day-old endometrial cells of mature follicles, where ERβ was distributed significantly. The overall expression of ERβ in the ovary was higher than that of ERα. The results of this study provide basic data on the ovarian development and the specific expression of ERs and PRs in the ovaries of Huanghuai white goats, which play an important role in ovarian development and precocity.

Correlation between the RNA Expression and the DNA Methylation of Estrogen Receptor Genes in Normal and Malignant Human Tissues.

Estrogen plays a multifaceted function in humans via interacting with the estrogen receptors ERα, ERβ, and G protein-coupled estrogen receptor 1 (GPER1). Previous research has predominantly concentrated on elucidating the signaling route of estrogen. However, the comprehensive understanding of the expression profile and control of these estrogen receptors in various human tissues is not well known. In the present study, the RNA levels of estrogen receptors in various normal and malignant human tissues were retrieved from the human protein atlas, the cancer genome atlas (TCGA), and the genotype-tissue expression (GTEx) databases for analyzing the expression profile of estrogen receptors through gene expression profiling interactive analysis (GEPIA). The status of DNA methylation of estrogen receptor genes from TCGA were analyzed through the software Wanderer and cBioPortal. The MethSurv tool was utilized to estimate the relevance between specific cytosine-guanine (CG) methylation and tumor survival. The expression profile analysis revealed that ERα, ERβ, and GPER1 have unique expression patterns in diverse tissues and malignancies. The interesting results were the higher expression of ERβ RNA in the male testis than in females and the positive association between the RNA level of ERα and the androgen receptor in different human normal tissues. Especially, the significant changes in GPER1 expression in multiple malignancies showed a consistent decrease with no exception, which indicates the role of GPER1 in common tumor inhibition. The finding on the expression profile provides clues for exploring novel potential physiological and pathophysiological functions of estrogen. The DNA methylation analysis manifested that the expression of GPER1 and ERα showed a substantial correlation with the methylation of specific CG sites in the cis-regulating region of the gene. However, no such association was observed for ERβ. When comparing tumor tissues to normal tissues, the DNA methylation of certain CG sites of estrogen receptors showed a correlation with tumor survival but did not always correlate with the expression of that gene or with the expression of DNA methyltransferases. We proposed that the variation in DNA methylation at different CG sites in estrogen receptor genes had other functions beyond its regulatory role in its gene expression, and this might be associated with the progression and therapy efficiency of the tumor based on the modulation of the chromatin configuration.

The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression.

Just like the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet the incomplete understanding of ERα functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for the treatment of this disease. Using 2 human PCa tissue microarray cohorts, we first demonstrate that nuclear ERα expression was heterogeneous among patients, being detected in only half of the tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single-cell RNA-Seq analyses revealed that estrogens partially mimicked the androgen transcriptional response and activated specific biological pathways linked to proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed the regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprogrammed PCa metabolism, was associated with disease progression, and could be targeted for therapeutic purposes.

Abstract 3046: The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression

Abstract Just as the androgen receptor (AR), the estrogen receptor α (ERα) is expressed in the prostate and is thought to influence prostate cancer (PCa) biology. Yet, the incomplete understanding of ERα cellular functions in PCa hinders our ability to fully comprehend its clinical relevance and restricts the repurposing of estrogen-targeted therapies for treatment of this disease. Using two human PCa tissue microarray cohorts, we first demonstrated that nuclear ERα expression was heterogeneous between patients, being only detected in half of tumors. Positive nuclear ERα levels were correlated with disease recurrence, progression to metastatic PCa, and patient survival. Using in vitro and in vivo models of the normal prostate and PCa, bulk and single cell RNA-seq analyses revealed that estrogens partially mimic the androgen transcriptional response and induce specific biological pathways linked to cellular proliferation and metabolism. Bioenergetic flux assays and metabolomics confirmed regulation of cancer metabolism by estrogens, supporting proliferation. Using cancer cell lines and patient-derived organoids, selective estrogen receptor modulators, a pure anti-estrogen, and genetic approaches impaired cancer cell proliferation and growth in an ERα-dependent manner. Overall, our study revealed that, when expressed, ERα functionally reprograms PCa metabolism, is associated with disease progression, and could be targeted for therapeutic purposes. Citation Format: Camille Lafront, Lucas Germain, Gabriel H. Campolina-Silva, Cindy Weidmann, Line Berthiaume, Hélène Hovington, Hervé Brisson, Cynthia Jobin, Lilianne Frégeau-Proulx, Raul Cotau, Kevin Gonthier, Aurélie Lacouture, Patrick Caron, Claire Ménard, Chantal Atallah, Julie Riopel, Éva Latulippe, Alain Bergeron, Paul Toren, Chantal Guillemette, Martin Pelletier, Yves Fradet, Clémence Belleannée, Frédéric Pouliot, Louis Lacombe, Éric Lévesque, Étienne Audet-Walsh. The estrogen signaling pathway reprograms prostate cancer cell metabolism and supports proliferation and disease progression [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 3046.

Father’s Absence in the Mongolian gerbil (Meriones unguiculatus) is associated with alterations in paternal behavior, T, cort, presence of ERα, and AR in mPOA/ BNST

Testosterone (T), estrogen receptor alpha (ERα), and androgen receptor (AR) play a significant role in the regulation of paternal behavior. We determined the effects of deprivation of paternal care on alterations in paternal behavior, T concentrations in plasma, and the presence of ERα and AR in the medial preoptic area (mPOA), bed nucleus of the stria terminalis (BNST), medial amygdala (MeA), and olfactory bulb (OB), as well as the corticosterone (CORT) concentrations in plasma caused by deprivation of paternal care in the Mongolian gerbil (Meriones unguiculatus). Twenty pairs of gerbils were formed; the pups were deprived of paternal care (DPC) in 10 pairs. In another 10 pairs, the pups received paternal care (PC). Ten males raised in DPC condition and 10 males raised in PC conditions were mated with virgin females. When they became fathers, each DPC male and PC male was subjected to tests of paternal behavior on day three postpartum. Blood samples were obtained to quantify T and CORT concentrations, and the brains were removed for ERα and AR immunohistochemistry analyses. DPC males gave less care to their pups than PC males, and they had significantly lower T concentrations and levels of ERα and AR in the mPOA and BNST than PC males. DPC males also had higher CORT concentrations than PC males. These results suggest that in the Mongolian gerbil father’s absence causes a decrease in paternal care in the offspring, which is associated with alterations in the neuroendocrine mechanisms that regulate it.

Modulation of Estrogen Receptor Alpha (ERα) and Tumor Suppressor Gene BRCA1 in Breast Cancer Cells by Bazedoxifene Acetate (BZA).

Selective estrogen receptor modulators (SERMs) are steroid analogs with dual functionality, acting as partial estrogen receptor agonists to preserve postmenopausal bone density and as estrogen receptor antagonists in breast tissue. Bazedoxifene acetate (BZA) is an FDA-approved, third-generation SERM used in the treatment of osteoporosis in women. It demonstrates potential as a therapeutic option for breast cancer patients undergoing endocrine therapy. Our study aimed to assess BZA's effects on Estrogen Receptor Alpha (ERα) and tumor suppressor gene BRCA1 in T-47D and MCF-7 breast cancer cells, using Western blots, cellular viability, apoptosis assays, and RT-qPCR. Cells were cultured in 5% charcoal-stripped fetal bovine serum for six days to deplete endogenous steroids. Following a 24 h exposure to 2 µM BZA (optimal concentration determined from 1 nM-2 µM studies), Western blot analyses revealed reduced ERα and BRCA1 protein levels in both cell lines. ERα decreased by 48-63% and BRCA1 by 61-64%, indicating sensitivity to antiestrogens. Cytolocalization of ERα and BRCA1 remained unchanged after BZA and 17-β-estradiol (E2) treatment. ESR1 mRNA expression correlated with Western blot findings. Image cytometric analysis using the stain, propidium iodide, detected decreased cellular proliferation in T-47D and MCF-7 cells following a 6-day treatment ranging from 1 nM to 2 µM BZA. BZA treatment alone led to a tenfold reduction in cellular proliferation compared to estrogen-treated cells, suggesting antiproliferative effects. Understanding BZA's modulation of BRCA1 and ERα, along with their mechanistic interactions, is vital for comprehending its impact on breast cancer tumor suppressors and hormone receptors.

PMM2 controls ERα levels and cell proliferation in ESR1 Y537S variant expressing breast cancer cells

PurposeMetabolic reprogramming in breast cancer (BC) subtypes offers potential personalized treatment targets. Estrogen receptor α (ERα)-positive BC patients undergoing endocrine therapy (ET) can develop ET-resistant metastatic disease. Specific mutations, like Y537S in ERα, drive uncontrolled cell proliferation. Targeting mutant receptor levels shows promise for inhibiting growth in metastatic BC expressing ERα variants. Additionally, metabolic reprogramming occurs in ERα Y537S mutant cells. Consequently, we conducted a screen to identify metabolic proteins reducing intracellular levels of ERα Y537S and inhibiting cell proliferation. MethodsNine metabolic proteins were identified in a siRNA-based screen, with phosphomannose mutase 2 (PMM2) showing the most promise. We measured the impact of PMM2 depletion on ERα stability and cell proliferation in ERα Y537S mutant cells. Additionally, we tested the effect of PMM2 reduction on the hyperactive phenotype of the mutant and its proliferation when combined with metastatic BC treatment drugs. ResultsPMM2 emerged as a significant target due to its correlation with better relapse-free survival, overexpression in ERα-positive tumors, and its elevation in ERα Y537S-expressing cells. Depletion of PMM2 induces degradation of ERα Y537S, inhibits cell proliferation, and reduces ERα signaling. Notably, reducing PMM2 levels re-sensitizes ERα Y537S-expressing cells to certain ET drugs and CDK4/CDK6 inhibitors. Mechanistically, depletion of PMM2 leads to a reduction in ESR1 mRNA levels, resulting in decreased ERα receptor protein expression. Furthermore, the reduction of PMM2 decreases FOXA1 levels, which plays a crucial role in ERα regulation. ConclusionsOur findings establish PMM2 as an innovative therapeutic target for metastatic BC expressing the ERα Y537S variant, offering alternative strategies for managing and treating this disease.

The Herbal Combination Shu Gan Jie Yu Regulates the SNCG/ER-a/AKT-ERK Pathway in DMBA-Induced Breast Cancer and Breast Cancer Cell Lines Based on RNA-Seq and IPA Analysis.

Soothing the liver (called Shu Gan Jie Yu in Chinese, SGJY) is a significant therapeutic method for breast cancer in TCM. In this study, 3 liver-soothing herbs, including Cyperus rotundus L., Citrus medica L. var. sarcodactylis Swingle and Rosa rugosa Thunb. were selected and combined to form a SGJY herbal combinatory. To investigate the inhibiting effect of SGJY on breast cancer in vivo and vitro, and to explore the potential mechanisms. SGJY herbal combination was extracted using water. A breast cancer rat model was developed by chemical DMBA by gavage, then treated with SGJY for 11 weeks. The tumor tissue was preserved for RNA sequencing and analyzed by IPA software. The inhibition effects of SGJY on MCF-7 and T47D breast cancer cells were investigated by SRB assay and cell apoptosis analysis, and the protein expression levels of SNCG, ER-α, p-AKT and p-ERK were measured by western blotting. SGJY significantly reduced the tumor weight and volume, and the level of estradiol in serum. The results of IPA analysis reveal SGJY upregulated 7 canonical pathways and downregulated 16 canonical pathways. Estrogen receptor signaling was the key canonical pathway with 9 genes downregulated. The results of upstream regulator analysis reveal beta-estradiol was the central target; the upstream regulator network scheme showed that 86 genes could affect the expression of the beta-estradiol, including SNCG, CCL21 and MB. Additionally, SGJY was verified to significantly alter the expression of SNCG mRNA, CCL21 mRNA and MB mRNA which was consistent with the data of RNA-Seq. The inhibition effects of SGJY exhibited a dose-dependent response. The apoptosis rates of MCF7 and T47D cells were upregulated. The protein expression of SNCG, ER-α, p-AKT and p-ERK were all significantly decreased by SGJY on MCF-7 and T47D cells. The results demonstrate that SGJY may inhibit the growth of breast cancer. The mechanism might involve downregulating the level of serum estradiol, and suppressing the protein expression in the SNCG/ER-α/AKT-ERK pathway.