Cytoplasmic Estrogen Receptor Research Articles

Abstract PO4-26-04: Immunolocalization of cytoplasmic ER in ER-negative breast carcinoma as a potent favorable prognostic predictor

Abstract Background: It is known that estrogen receptor (ER) has extranuclear signaling functions in addition to classical genomic pathway, and estrogenic actions have been reported in ER-negative breast carcinoma cells. However, significance of cytoplasmic-ER immunoreactivity has not been reported in ER-negative breast carcinoma tissues. Methods: We immunolocalized cytoplasmic ER in 155 ER-negative breast carcinoma tissues and evaluated its clinicopathological significance including the prognosis. As a comparative cohort set, we also used 142 ER-positive breast carcinomas. Results: Cytoplasmic-ER immunoreactivity was detected in the carcinoma cells, but not in the non-neoplastic mammary epithelium. Cytoplasmic-ER immunoreactivity was positive in the 35 out of 155 (23%) ER-negative breast carcinoma cases, whereas it was detected only in 2 out of 142 (1.4%) ER-positive cases. Cytoplasmic ER status was positively associated with cytoplasmic-PR status, but inversely associated with Ki67 labeling index or distant free-relapse survival rate. Moreover, cytoplasmic-ER status turned out to be an independent good prognostic factor for both distant relapse-free survival and breast cancer specific survival. Conclusion: These findings suggested that cytoplasmic ER plays important roles in the ER-negative breast carcinoma, and cytoplasmic ER is a potent good prognostic factor. (accepted in Acta Histochemica et Cytochemica, 2023/Jun/27) Citation Format: Akiko Ebata, Takashi Suzuki, Narumi Harada-Shoji, Yohei Hamanaka, Minoru Miyashita, Erina Iwabuchi, Kiyoshi Takagi, Yasuhiro Miki, Hiroshi Tada, Takanori Ishida. Immunolocalization of cytoplasmic ER in ER-negative breast carcinoma as a potent favorable prognostic predictor [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 PO4-26-04.

Critical Roles of SRC-3 in the Development and Progression of Breast Cancer, Rendering It a Prospective Clinical Target

Breast cancer (BCa) is the most frequently diagnosed malignant tumor in women and is also one of the leading causes of cancer-related death. Most breast tumors are hormone-dependent and estrogen signaling plays a critical role in promoting the survival and malignant behaviors of these cells. Estrogen signaling involves ligand-activated cytoplasmic estrogen receptors that translocate to the nucleus with various co-regulators, such as steroid receptor co-activator (SRC) family members, and bind to the promoters of target genes and regulate their expression. SRC-3 is a member of this family that interacts with, and enhances, the transcriptional activity of the ligand activated estrogen receptor. Although SRC-3 has important roles in normal homeostasis and developmental processes, it has been shown to be amplified and overexpressed in breast cancer and to promote malignancy. The malignancy-promoting potential of SRC-3 is diverse and involves both promoting malignant behavior of tumor cells and creating a tumor microenvironment that has an immunosuppressive phenotype. SRC-3 also inhibits the recruitment of tumor-infiltrating lymphocytes with effector function and promotes stemness. Furthermore, SRC-3 is also involved in the development of resistance to hormone therapy and immunotherapy during breast cancer treatment. The versatility of SRC-3 in promoting breast cancer malignancy in this way makes it a good target, and methodical targeting of SRC-3 probably will be important for the success of breast cancer treatment.

Immunolocalization of Cytoplasmic ER in ER-negative Breast Carcinoma as a Potent Favorable Prognostic Predictor.

It is known that estrogen receptor (ER) has extranuclear signaling functions in addition to classical genomic pathway, and estrogenic actions have been reported in ER-negative breast carcinoma cells. However, significance of cytoplasmic-ER immunoreactivity has not been reported in ER-negative breast carcinoma tissues. We immunolocalized cytoplasmic ER in 155 ER-negative breast carcinoma tissues and evaluated its clinicopathological significance including the prognosis. As a comparative cohort set, we also used 142 ER-positive breast carcinomas. Cytoplasmic-ER immunoreactivity was detected in the carcinoma cells, but not in the non-neoplastic mammary epithelium. Cytoplasmic-ER immunoreactivity was positive in the 35 out of 155 (23%) ER-negative breast carcinoma cases, whereas it was detected only in 2 out of 142 (1.4%) ER-positive cases. Cytoplasmic ER status was positively associated with cytoplasmic-PR status, but inversely associated with Ki67 labeling index or distant free-relapse survival rate. Moreover, cytoplasmic-ER status turned out to be an independent good prognostic factor for both distant relapse-free survival and breast cancer specific survival. These findings suggested that cytoplasmic ER plays important roles in the ER-negative breast carcinoma, and cytoplasmic ER is a potent good prognostic factor. Among the ER-negative breast cancer patients, clinical benefit of chemotherapy may be limited in the cytoplasmic-ER positive cases.

Abstract 329: Understanding the role of GPR30 in the estrogen non-genomic signaling in inflammatory breast cancer

Abstract Inflammatory Breast Cancer (IBC) is rare and the most aggressive subtype of all breast cancers, reporting rapid progression, poor prognosis, and a unique clinical diagnosis (blockage of lymph vessels by tumor emboli). Approximately, 40% of IBC cases are classified as triple-negative breast cancer (TNBC), meaning they test negative for hormone receptors (estrogen and progesterone) and the amplification of the epidermal growth factor receptor 2 (HER2), which leads to no effective targeted therapies availability. However, 17β-estrogen (E2) has been found to enhance the migration and invasion phenotypes of TN-IBC cells and it has been associated with the presence of a membrane G-protein coupled estrogen receptor (GPR30) and a novel cytoplasmic estrogen receptor (ERα36 isoform) that can undergo an estrogen non-genomic (rapid) cell’s response. Recent studies have also reported a crosstalk between these estrogen non-genomic receptors and the epidermal growth factor receptor (EGFR) signaling pathway in the presence of E2, inducing phosphorylation of the extracellular signal-regulated kinase (ERK1/2) and promoting oncogenic phenotypes (migration & invasion) in TN-IBC cells. However, the exact role of GPR30 and ERα36 in the non-genomic signaling pathway remains elusive in TN-IBC. We hypothesis that GPR30 and ERα36 are necessary to undergo de estrogen non-genomic signaling and promote oncogenic phenotypes in TN-IBC SUM149 cells after E2 treatment. Methods: We have measured migratory activity and tumor emboli formation of SUM149 cells (by wound-healing and 3D-cell proliferation assay), and phosphorylation levels of ERK1/2 and AKT kinases (by western-blot) after treatments in time-points with E2 alone and in combination with G15 (GPR30 antagonist drug). We are also working to identify protein partners of GPR30 (by Ip and Mass-spec) after E2 treatment, including physical interaction with ERα36, in TN-IBC and other types of breast cancers. Results: G15 treatment in Sum149 cells significantly reduced E2-induced ERK1/2 phosphorylation, indicating that GPR30 is necessary for the estrogen non-genomic signaling pathway and has direct involvement with the EGFR signaling cascade. Data acquired from these experiments will contribute to a better understanding of TN-IBC’s molecular structure and create new opportunities to develop novel targeted therapies. Citation Format: Xavier S. Bittman Soto, Adrian J. Rivera Lopez, Esther A. Peterson. Understanding the role of GPR30 in the estrogen non-genomic signaling in inflammatory breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 329.

Tamoxifen overcomes the trastuzumab-resistance of SK-BR-3 tumorspheres by targeting crosstalk between cytoplasmic estrogen receptor α and the EGFR/HER2 signaling pathway

Since trastuzumab-resistance remains a major obstacle to the successful treatment of HER2-positive breast cancer, a detailed understanding of the mechanisms responsible is required to direct future pharmacotherapeutic strategies. Recently, several studies have indicated that the quiescent natures of cancer stem cells contribute to treatment resistance and tumor recurrence. Thus, in this study, we investigated the mechanism underlying trastuzumab resistance in a quiescent cell population using tumorsphere cultures and explored better therapeutic strategies to overcome trastuzumab resistance in HER2-positive breast cancer patients. We observed that most cells in SK-BR-3 tumorspheres were quiescent, showing the accumulation of cells at the G0/G1 phase as compared to cells in monolayer culture. Furthermore, SK-BR-3 tumorspheres exhibited enhanced EGFR/HER2 signaling, which was incompletely inhibited by trastuzumab, and subsequently led to trastuzumab-resistance. Interestingly, cytoplasmic estrogen receptor α (ERα) expression was markedly elevated in tumorspheres and was associated with enhanced EGFR/HER2 signaling. Accordingly, inhibition of ERα with tamoxifen selectively targeted tumorspheres rather than cells in monolayer culture and overcame trastuzumab resistance in tumorspheres. Taken together, our findings indicate that crosstalk between cytoplasmic ERα and the HER2/EGFR signaling pathway can be considered a novel therapeutic target for quiescent cell populations within HER2-positive breast cancer and that simultaneous inhibition of ER and the EGFR/HER2 pathway may prevent trastuzumab resistance. We hope that these results provide a basis for the use of combinations of tamoxifen and trastuzumab in HER2-positive breast cancer patients.

EGFR Inhibitors and Apoptosis Inducers : Design, Docking, Synthesis, and Anticancer Activity of Novel Tri-Chalcone Derivatives

Estrogen receptors (ERs) are primarily expressed in cancer cells and interfere with the epidermal growth factor (EGFR) signal pathway. However, data are limited regarding the interaction between cytoplasmic ER expression and EGFR-tyrosine kinase inhibitor response. The objective of this study was to design multi-target molecules for enhancing anti-cancer activity and decreasing drug resistance. Two distinct series of tri-chalcone derivatives S1(1-7), S2(1-7) with promising anti-cancer activity was incorporated into the current study. Compounds S1(1-2) and S2(1-2) demonstrated the highest binding affinity for interactions with the active EGFR binding site. Interestingly, compounds S1-1 and S1-2 have shown a potent cytotoxicity of MCF-7 (2.23 ± 0.11 and 2.04 ± 0.71 µM) and MDA-MB-231 (6.44 ± 0.01 and 3.75 ± 0.26 µM), respectively, relative to tamoxifen IC50 of 9.3 ± 0.44 and 18.92 ± 1.43 µM. Thus, in-vitro EGFR activity was evaluated for compounds S1-1 and S1-2. The results indicated that compounds S1-1 and S1-2 showed a significant improvement in the anti-cancer resistant treatment due to their potential effects on the EGFR and the possible anti-ER effect.

Cytoplasmic ERα and NFκB Promote Cell Survival in Mouse Mammary Cancer Cell Lines.

There is a desperate need in the field for mouse mammary tumors and cell lines that faithfully mimic estrogen receptor (ER) expression and activity found in human breast cancers. We found that several mouse mammary cancer cell lines express ER but fail to demonstrate classical estrogen-driven proliferation or transcriptional activity. We investigated whether these cell lines may be used to model tamoxifen resistance by using small molecule inhibitors to signaling pathways known to contribute to resistance. We found that the combination of NFκB inhibition and ER antagonists significantly reduced cell proliferation in vitro, as well as growth of syngeneic tumors. Surprisingly, we found that ER was localized to the cytoplasm, regardless of any type of treatment. Based on this, we probed extra-nuclear functions of ER and found that co-inhibition of ER and NFκB led to an increase in oxidative stress and apoptosis. Together, these findings suggest that cytoplasmic ER and NFκB may play redundant roles in protecting mammary cancer cells from oxidative stress and cell death. Although this study has not identified a mouse model with classical ER activity, cytoplasmic ER has been described in a small subset of human breast tumors, suggesting that these findings may be relevant for some breast cancer patients.

Estrogen receptor \u03b2 is associated with expression of cancer associated genes and survival in ovarian cancer

BackgroundIn ovarian cancer, the role of estrogen receptors (ERs), particularly of ERβ, being suggested as tumor suppressor in breast and prostate cancer, remains unclear. We examined the expression of nuclear and cytoplasmic ERβ in ovarian cancer and correlated it with expression of ovarian cancer markers CA125, CEA and CA72–4, steroid hormone receptors ERα and PR, cancer-associated genes EGFR, p53, HER2 and proliferation marker Ki-67. Additionally we examined to what extent expression of ERβ and the other proteins affects survival of ovarian cancer patients.MethodsWe established a tissue microarray from 171 ovarian cancer patients and performed immunohistochemical analyses of the mentioned proteins.ResultsNuclear ERβ was detected in 47.31% of the ovarian cancer tissues and cytoplasmic expression of this receptor was observed in 23.08%. Nuclear expression of ERβ was significantly decreased in the G3 subgroup compared to better differentiated cancers (p < 0.01) and correlated with ovarian cancer markers CEA (95% CI 0.1598–0.4465; p < 0.0001) and CA72–4 (95% CI 0.05953–0.3616; p < 0.01). Cytoplasmic ERβ expression correlated with EGFR levels (95% CI 0.1059–0.4049; p < 0.001). ERα expression was associated with expression of CA125 and PR. Overall survival of patients with tumors expressing cytoplasmic ERβ was significant longer compared to those with ERβ-negative ovarian cancer (chi-square statistic of the log-rank, p < 0.05). Progression-free survival was dependent on expression of PR (chi-square statistic of the log-rank, p < 0.05) and Ki-67 (p = 0.05).ConclusionsOur data suggest an important, but distinct role of nuclear and cytoplasmic ERβ expression in ovarian cancer and encourage further studies on its role in this cancer entity.

Cytoplasmic expression of estrogen receptor β may predict poor outcome of EGFR-TKI therapy in metastatic lung adenocarcinoma.

There is growing evidence that estrogen receptors (ER) are expressed in lung cancer cells, and are able to interact with the epidermal growth factor receptor (EGFR) signaling pathway. However, data on the association between cytoplasmic ER expression and the response to EGFR-tyrosine kinase inhibitors (TKI) treatment are limited. The aim of the present study was to investigate the associations between ERα/ERβ expression and EGFR mutational status and response to TKI treatment in metastatic lung adenocarcinoma. A retrospective study of 126 consecutive patients with lung adenocarcinoma who were diagnosed with stage IV disease and had received EGFR-TKI treatment was conducted. ER expression was detected by immunohistochemistry. EGFR and GTPase KRas (KRAS) mutational statuses were evaluated by denaturing high performance liquid chromatography and PCR-restriction fragment length polymorphism, respectively. In the overall cohort of 126 lung adenocarcinoma samples analyzed, ERα expression in the nucleus of tumor cells was identified in 17 (18.9%) patients, whereas ERβ expression was identified in the nucleus (22/126, 17.5%) and cytoplasm (17/126, 13.5%). The nuclear expression of ERβ was positively associated with the degree of tumor differentiation (P=0.010). EGFR-sensitizing mutations were significantly associated with improved objective response rates (ORR), disease control rates (DCR), median progression-free survival (mPFS) and median overall survival (mOS) (P<0.001; P<0.001; P=0.003; and P=0.026, respectively). Patients with cytoplasmic ERβ expression exhibited non-significant poorer ORR, DCR, mPFS and mOS compared with patients without cytoplasmic ERβ expression (P=0.082; P=0.106; P=0.084; and P=0.119, respectively). However, the significant decrease of ORR, DCR and mPFS was observed in patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations (P=0.030; P=0.009; and P=0.018, respectively) in comparison with the subgroup with EGFR sensitizing mutations but negative expression of cytoplasmic ERβ. A trend towards shorter mOS was also observed in patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations (P=0.071). No KRAS mutations were identified in patients with cytoplasmic ERβ expression. Subsequent to adjusting for sex, smoking status and EGFR mutation status, the Cox repression analysis indicated that cytoplasmic expression of ERβ was a negative independent predictor for mPFS in the whole patient cohort (HR=1.870; 95% confidence interval 1.058–3.305; P=0.031). Cytoplasmic ERβ expression was negatively correlated with the efficacy of EGFR-TKI treatment for metastatic lung adenocarcinoma, particularly for patients with coexisting cytoplasmic ERβ expression and EGFR-sensitizing mutations. Cytoplasmic ERβ may be a promising marker to predict the outcome of EGFR-TKI treatment.

Randomized phase II trial of fulvestrant alone or in combination with bortezomib in hormone receptor-positive metastatic breast cancer resistant to aromatase inhibitors: a New York Cancer Consortium trial.

The proteasome inhibitor bortezomib enhances the effect of the selective estrogen receptor (ER) downregulator (SERD) fulvestrant by causing accumulation of cytoplasmic ER aggregates in preclinical models. The purpose of this trial was to determine whether bortezomib enhanced the effectiveness of fulvestrant. One hundred eighteen postmenopausal women with ER-positive metastatic breast cancer resistant to aromatase inhibitors (AIs) were randomized to fulvestrant alone (Arm A—500 mg intramuscular (i.m.) day −14, 1, 15 in cycle 1, and day 1 of additional cycles) or in combination with bortezomib (Arm B—1.6 mg/m2 intravenous (i.v.) on days 1, 8, 15 of each cycle). The study was powered to show an improvement in median progression-free survival (PFS) from 5.4 to 9.0 months and compare PFS rates at 6 and 12 months (α=0.10, β=0.10). Patients with progression on fulvestrant could cross over to the combination (arm C). Although there was no difference in median PFS (2.7 months in both arms), the hazard ratio for PFS in Arm B versus Arm A (referent) was 0.73 (95% confidence interval (CI)=0.49, 1.09, P=0.06, 1-sided log-rank test, significant at the prespecified 1-sided 0.10 α level). At 12 months, the PFS proportion in Arm A and Arm B was 13.6% and 28.1% (P=0.03, 1-sided χ2-test; 95% CI for difference (14.5%)=−0.06, 29.1%). Of 27 patients on arm A who crossed over to the combination (arm C), 5 (18%) were progression-free for at least 24 weeks. Bortezomib likely enhances the effectiveness of fulvestrant in AI-resistant, ER-positive metastatic breast cancer by reducing acquired resistance, supporting additional evaluation of proteasome inhibitors in combination with SERDs.

Activation of G protein-coupled estrogen receptor 1 mimics, but does not mediate, the anti-proliferative action of estradiol on pituitary lactotrophs in primary culture.

Estrogen binds to nuclear estrogen receptors (ERs) to modulate transcription of target genes in estrogen-responsive cells. However, recent studies have shown that estrogen also binds to cytoplasmic membrane ERs to modulate protein kinase signaling cascades, leading to non-genomic actions. We investigated whether either nuclear or membrane ERs, including G protein-coupled estrogen receptor 1 (Gper1), mediate the inhibitory action of estrogen on insulin-like growth factor-1 (IGF-1)-induced proliferation of pituitary lactotrophs in primary culture. The cytoplasmic membrane-impermeable bovine serum albumin-conjugated estradiol (BSA-E2) at 1 nM, an equimolar concentration at which 17β-estradiol (E2) exerts anti-proliferative effects, did not inhibit IGF-1-induced lactotroph proliferation. In contrast, diethylstilbestrol, which is known to selectively activate nuclear ERs but not membrane ERs, inhibited IGF-1-induced proliferation and modulated mRNA expression of estrogen-responsive genes to a similar degree as E2. Activation of Gper1 by its agonist G-1 inhibited IGF-1-induced proliferation in a dose-dependent manner, but it had little effect on modulation of mRNA expression of estrogen-responsive genes. However, blockade of Gper1 by its antagonist G-15 did not affect the inhibitory action of E2 on IGF-1-induced proliferation. Here, we demonstrate that E2 inhibition of lactotroph proliferation is due to nuclear ER-mediated genomic action. Our results suggest that activation of Gper1 mimics, but does not mediate, the anti-proliferative action of E2 on lactotrophs.

Evaluation of Anticancer Activity of Ethanolic and Ethylacetoacetate Extracts of Sweet Cherry Against Human Breast Cancer Cell Line MCF-7

MCF-7 is a breast cancer cell line isolated in 1970 from a 69-year-old Caucasian woman. MCF-7 is the acronym of Michigan Cancer Foundation-7, referring to the institute in Detroit where the cell line was established in 1973 by Herbert Soule and co-workers. The MCF7 line retains several characteristics of differentiated mammary epithelium including ability to process estradiol via cytoplasmic estrogen receptors and the capability of forming domes. The cells express the WNT7B oncogene. Growth of MCF7 cells is inhibited by tumor necrosis factor alpha (TNF alpha). Secretion of IGFBP's can be modulated by treatment with anti-estrogens. PIK3CA helical mutations were identified in MCF-7, but with low AKT activation. The main objective of the present research work is to isolate the bioactive molecules and evaluate the in vitro anticancer activity of ethanolic and ethyl acetoacetate extracts of sweet cherry (EEC and EAAEC) of Prunus avium. The in vitro anticancer activity was carried out against human breast cancer cell line MCF-7 by MTT assay. The results obtained from the in-vitro studies performed by MTT assay by using human breast cancer cell line MCF-7 displayed that the various extracts of sweet cherry (EEC and EAAEC) possessed a very good anticancer activity. From the present studied it had been concluded that EEC and EAAEC, all were exhibiting the potential capability to inhibit the cancer cell when compared with standard drug doxorubicin and the cell growth inhibition of EEC and EAAEC was found to be the highest 92.90% growth inhibition at 10 μg (IC50 = 2.4 μg/ml) and EAAEC with the 92.49% growth inhibition at 10 μg (IC50 = 2.9 μg/ml).

Mitochondrial estrogen receptor β2 drives antiapoptotic pathways in advanced serous ovarian cancer.

We previously showed an unfavorable prognostic role of the cytoplasmic estrogen receptor β2 (cERβ2) in serous ovarian cancer. Here we aimed to investigate molecular determinants in cell survival function of cERβ2 in this malignant disease. We used immunohistochemistry to evaluate differences in apoptosis (quantified by the expression of cleaved caspase-3) and cell proliferation (quantified by the expression of Ki-67) in 56 advanced serous ovarian cancer cases, stratified according to the absence or presence of estrogen receptor β2 (ERβ2) protein in the cytoplasmic compartment (31 cERβ2- and 25 cERβ2+ cases, respectively). Thereafter, by immunofluorescence, we visualized the subcellular distribution of ERβ2, and by the proximity ligation assays, we characterized in situ its ability to interact with other proteins specifically involved in the apoptosis cascade. Finally, we assessed cytochrome c expression by immunohistochemistry. We demonstrated that, although not affecting tumor proliferation, cytoplasmic ERβ2 expression was indeed associated to a lower apoptotic rate in ovarian cancer cases. Then, we proved that cERβ2 is targeted to mitochondria where it interacts as a binding partner with BAD (B-cell lymphoma [Bcl] 2-associated death promoter). This interaction, precluding the Bcl-xL (B-cell lymphoma extra large)/BAD heterodimer formation, inhibited Bax (Bcl-2-like protein 4) oligomerization, the release of cytochrome c, and ultimately apoptosis. In conclusion, we provide in vivo mechanistic evidence for an antiapoptotic function of mitochondrial ERβ2, a finding supporting the value of its cytoplasmic expression as an unfavorable prognostic biomarker for serous ovarian cancer.

English

Tamoxifen is one of the modalities in the treatment for breast cancer, especially in postmenopausal patients. It acts primarily as an anti-estrogenic agent, due to its cytoplasmic estrogen receptor binding capacity. However, the same also exerts a mild estrogenic effect. Here with a case of ER positive carcinoma breast treated with Tamoxifen for 5 years, presented as post- menopausal bleeding per vaginum, showed an enhanced mass occupying the endometrial cavity, measuring >30mm is presented. Total hysterectomy was done.

Novel G Protein-Coupled Oestrogen Receptor GPR30 Shows Changes in mRNA Expression in the Rat Brain over the Oestrous Cycle

Oestrogen influences autonomic function via actions at classical nuclear oestrogen receptors α and β in the brain, and recent evidence suggests the orphan G protein-coupled receptor GPR30 may also function as a cytoplasmic oestrogen receptor. We investigated the expression of GPR30 in female rat brains throughout the oestrous cycle and after ovariectomy to determine whether GPR30 expression in central autonomic nuclei is correlated with circulating oestrogen levels. In the nucleus of the solitary tract (NTS), ventrolateral medulla (VLM) and periaqueductal gray (PAG) GPR30 mRNA, quantified by real-time PCR, was increased in proestrus and oestrus. In ovariectomised (OVX) rats, expression in NTS and VLM appeared increased compared to metoestrus, but in the hypothalamic paraventricular nucleus and PAG lower mRNA levels were seen in OVX. GPR30-like immunoreactivity (GPR30-LI) colocalised with Golgi in neurones in many brain areas associated with autonomic pathways, and analysis of numbers of immunoreactive neurones showed differences consistent with the PCR data. GPR30-LI was found in a variety of transmitter phenotypes, including cholinergic, serotonergic, catecholaminergic and nitrergic neurones in different neuronal groups. These observations support the view that GPR30 could act as a rapid transducer responding to oestrogen levels and thus modulate the activity of central autonomic pathways.

Cytoplasmic estrogen receptor β as a potential marker in human non-small cell lung carcinoma

Objectives:Estrogen has been reported to promote an increased susceptibility to lung cancer development. This study focusses on the role of cytoplasmic estrogen receptor β (c-ERβ) in NSCLC.Methods:NSCLC (n = 162) cases were analyzed using immunohistochemistry (IHC) for c-ERβ expression and its association with clinicopathological variables. Significance of c-ERβ expression was further examined using in vitro studies in NSCLC cell lines.Results:Among ERβ and aromatase positive NSCLC females, c-ERβ was significantly associated with greater tumor diameter and tended to be associated with worse overall survival. A549 and LCAM1 cells expressed aromatase, as well as c-ERβ and nuclear ERβ (n-ERβ). U0126 (MAPK/extracellular-signal-regulated kinase (ERK) inhibitor) abrogated MAPK phosphorylation, caused by estradiol via c-ERβ, more effectively than ICI 182780 (ER blocker) in either cell line. However, ICI 182780 completely abrogated the estrogen responsive elements (ERE)-luciferase activity caused by estradiol. Combination therapy with ICI 182780 and U0126 turned out to be far more effective than either treatment alone in either A549 or LCAM1 cells.Conclusion:The results indicated that ERβ may contribute to NSCLC via non-genomic action of estrogen through its cytoplasmic form, in addition to the genomic actions via n-ERβ. These actions of estrogen in NSCLCs may be abrogated by combination therapy with ICI 182780 and U0126.

Cytoplasmic Estrogen Receptor in Breast Cancer

In addition to genomic signaling, it is accepted that estrogen receptor-α (ERα) has nonnuclear signaling functions, which correlate with tamoxifen resistance in preclinical models. However, evidence for cytoplasmic ER localization in human breast tumors is less established. We sought to determine the presence and implications of nonnuclear ER in clinical specimens. A panel of ERα-specific antibodies (SP1, MC20, F10, 60c, and 1D5) was validated by Western blot and quantitative immunofluorescent (QIF) analysis of cell lines and patient controls. Then eight retrospective cohorts collected on tissue microarrays were assessed for cytoplasmic ER. Four cohorts were from Yale (YTMA 49, 107, 130, and 128) and four others (NCI YTMA 99, South Swedish Breast Cancer Group SBII, NSABP B14, and a Vietnamese Cohort) from other sites around the world. Four of the antibodies specifically recognized ER by Western and QIF analysis, showed linear increases in amounts of ER in cell line series with progressively increasing ER, and the antibodies were reproducible on YTMA 49 with Pearson correlations (r(2) values) ranging from 0.87 to 0.94. One antibody with striking cytoplasmic staining (MC20) failed validation. We found evidence for specific cytoplasmic staining with the other four antibodies across eight cohorts. The average incidence was 1.5%, ranging from 0 to 3.2%. Our data show ERα is present in the cytoplasm in a number of cases using multiple antibodies while reinforcing the importance of antibody validation. In nearly 3,200 cases, cytoplasmic ER is present at very low incidence, suggesting its measurement is unlikely to be of routine clinical value.

OT3-01-01: Randomized Phase II Study of Fulvestrant Versus Fulvestrant Plus Bortezomib in Postmenopausal Women with Estrogen Receptor (ER) Positive, Aromatase-Inhibitor (AI) Resistant Metastatic Breast Cancer (MBC): New York Cancer Consortium Trial P8457.

Abstract Background: Bortezomib ia proteasome inhibitor that enhances fulvestrant-mediated aggregation of the ER in the cytoplasm without blocking ER degradation in the nucleus in ER+ human breast cancer cell lines, thereby promoting cytoplasmic ER aggresomes which activate a sustained unfolded protein response leading to apoptotic cell death; the combination also induces tumor regression in a tamoxifen resistant T47D-cyclin D1 xenograft model more effectively than either agent alone (Clin Cancer Res 2011; 17: 2292–2300). Hypothesis: We hpothesize that the combination of fulvestrant and bortezomib will be more effective than fulvestrant alone in ER+, AI-resistant MBC. Trial design: This is an open-label randomized phase II design in which patients with MBC are randomized to receive fulvestrant alone (500 mg IM day −14, day +1, and day +14 during cycle 1, then 500 mg every 4 weeks on day +1 during cycle 2 and thereafter) or in combination with bortezomib (1.6 mg/m2 IV days +1, +8, +15 every cycle). Stratification factors for randomization include performance status (ECOG 0 vs. 1–2), measurable disease (yes vs. no), and prior chemotherapy for MBC (yes vs. no). Patients who progress on fulvestrant alone may cross over to the combination. Eligibility criteria: Postmenopausal women with ER+, Her2-negative, MBC who have progressive disease during AI therapy for metastatic disease, or relapse while receiving adjuvant AI therapy. Up to one prior chemotherapy regimen for metastatic disease is permitted. Specific aims: Primary Objective: To determine if the addition of bortezomib to fulvestrant significantly improves median progression-free survival (PFS), defined as the time from cycle 1, day 1 of therapy until disease progression or death from any cause. Secondary Objectives: To determine: (1) adverse event rates in both arms, (2) the clinical benefit rate (CBR — objective response [by RECIST 1.1] and/or progression free at 24 weeks), (3) the objective response and CBR after crossover from fulvestrant to fulvestrant plus bortezomib. Translational Objectives: To perform an exploratory analysis of the effects of the combination on intratumoral nuclear/cytoplasmic ER ratio, unfolded protein response (BiP), apoptotis (cleaved caspase 3, Bc1-2 phospho JNK.) Statistical methods: he median PFS for patients receiving fulvestrant alone is expected to be approximately 5.4 months based upon patients with AI-resistant disease enrolled on the CONFIRM trial ( J Clin Oncol 2010; 28: 4594–4600). The trial is designed to detect a 70% improved in median PFS to 9.0 months (alpha=0.10, beta =0.10), which will require 59 eligible patients in each arm. Present accrual and target accrual: 24/118 Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT3-01-01.

Cytoplasmic expression of oestrogen receptor beta (ERβ) as a prognostic factor in vulvar squamous cell carcinoma in elderly women

To investigate the prognostic value of cytoplasmic oestrogen receptor beta (ERβ) expression in a series of untreated patients with non-human papillomavirus (HPV)-related vulvar cancer. Immunohistochemistry was carried out using a polyclonal rabbit anti-human ERβ antibody. The nuclear and cytoplasmic expression of ERβ was evaluated in 33 patients. Cytoplasmic immunoreactivity was correlated with histopathological and molecular parameters (Ki67, p21), disease-free survival (DFS) and overall survival (OS). The expression of cytoplasmic ERβ was found to be associated with grade (P=0.006), while no association was found with any of the remaining variables examined. Cases with high cytoplasmic ERβ expression showed lower DFS and OS compared to cases with low cytoplasmic ERβ (P=0.007, P=0.01, respectively). There was also a progressive decline in both the DFS and OS with increasing tumour size (P=0.05, P=0.07, respectively) and with increasing depth of infiltration (P=0.14, P=0.07, respectively). On multivariate analysis, only tumour size and cytoplasmic ERβ staining retained an independent negative prognostic role for DFS and OS. The assessment of cytoplasmic ERβ expression could be helpful to identify poor prognosis in elderly patients with non-HPV-related vulvar squamous cell carcinoma (SCC).

Neonatal exposure to herbicide acetochlor alters pubertal development in female wistar rats

Objectives: The purpose of this study was to evaluate the effects of neonatal exposure to the herbicide acetochlor (ACT) on pubertal development and reproductive functions in female Wistar rats and to investigate capability of ACT to interfere with estradiol binding to rat uterine estrogen receptors (ERs) ex vivo.Methods: Acetochlor (7.68 and 15.36 mg/kg/day) was administered by subcutaneous injection from postnatal day (PND) 4–7, and vaginal opening, and estrous cyclicity were evaluated from PND 8-159. A second group of adult ovariectomized female rats was dosed for 6 days with ACT (153.6 mg/kg/day, oral gavage). The interference of ACT with the binding of [3H]Estradiol -17β to uterine nuclear and cytoplasmic estrogen receptors was analyzed ex vivo in receptor binding assay.Results: Both doses of ACT caused acceleration of the age at eye opening and vaginal patency that were significantly different from the control. In addition, altered estrous cyclicity was observed in the ACT (15.36 mg/kg/day) group with 54% of the female rats displaying irregular cycles at PND 159. While uterine weights were not altered, a significant accumulation of uterine nuclear estrogen receptors was observed in the ACT group.Conclusion: These results indicate that acetochlor can act as the endocrine disruptor and that endpoints related to pubertal development and reproductive functions sensitive sites are targeted with this persistent pollutant.