Either Estrogen Receptor Research Articles

Critical Role of Estrogens on Bone Homeostasis in Both Male and Female: From Physiology to Medical Implications.

Bone is a multi-skilled tissue, protecting major organs, regulating calcium phosphate balance and producing hormones. Its development during childhood determines height and stature as well as resistance against fracture in advanced age. Estrogens are key regulators of bone turnover in both females and males. These hormones play a major role in longitudinal and width growth throughout puberty as well as in the regulation of bone turnover. In women, estrogen deficiency is one of the major causes of postmenopausal osteoporosis. In this review, we will summarize the main clinical and experimental studies reporting the effects of estrogens not only in females but also in males, during different life stages. Effects of estrogens on bone involve either Estrogen Receptor (ER)α or ERβ depending on the type of bone (femur, vertebrae, tibia, mandible), the compartment (trabecular or cortical), cell types involved (osteoclasts, osteoblasts and osteocytes) and sex. Finally, we will discuss new ongoing strategies to increase the benefit/risk ratio of the hormonal treatment of menopause.

Prevalence of Molecular Subtypes of Breast Cancer: A Single Institutional Experience of 2062 Patients.

The aim of the study was to analyze the prevalence of molecular subtypes of all breast cancer patients treated at tertiary cancer centre in West India in 12 years. A retrospective observational study carried out in Tertiary Cancer Care Centre in Western India. Electronic medical records of all breast cancer patients were retrieved from the hospital database between March 2007 to March 2019. Patient's characteristic, histological features and molecular subtypes were collected and analyzed. A total of 2062 women fulfilled the criteria for this study and were analyzed. The median age of study population was 51 years (range 22-100 years). Among these, 1357 (65.8%) were of ≤55 years and 705 (34.2%) were over 55 years. The overall incidence of Hormonal Receptor-positive patients (either estrogen-receptor (ER) or progesterone-receptor (PR) or both) was 1162 (56.4%). The Mean tumor size was 3.8cm (range 0-18cm). The most common histology was IDC (96%). Axillary nodes were positive in 62.5%. Luminal type A was positive in 762 (37%) patients while Luminal type B was present in 157 (7.6%) patients. Basal-like subtype was observed in 537 (26%) patients while HER2 rich subtype was seen in 229 (11.1%). The incidence of Luminal A subtype increased with age. The highest observed among patients (72%) aged 70 years or more. Incidence of Basal like subtype was highest in patients less than 30 years (52%). Luminal-like disease is the most common molecular subtype in India. Identification of Basal like breast cancer, a highly aggressive, biologically and clinically distinct subtype different than its non-basal variant, is important for treatment planning and target therapy.

Regulation of Lipocalin 2 by Estrogen in Human Adipose Tissue—A Link between Erß Pathway and Insulin Resistance

We recently showed that the adipokine lipocalin 2 (LCN2) causes insulin resistance in human adipose tissue (AT). Its expression is induced by dexamethasone (Dex) in AT from pre-menopausal women, but not from post-menopausal women or men. We also found that males had higher levels of LCN2 mRNA than females. Together, this proposes a regulation of LCN2 by glucocorticoids and sex steroids. Subcutaneous (SC) AT from post-menopausal women (n=29, 67±7 Y, BMI 28±5 kg/m2) was incubated ± 17 β-hydroxy estradiol (E2, 0.01-100 nM) and ± Dex (0.3 µM) for 24 h and LCN2 mRNA levels were measured. AT was co-treated with E2 (1 nM) and 100 nM and either estrogen receptor (ER) α or β antagonist, MPP or PHTPP, respectively, or with an ERβ agonist (DPN, 100 nM) for 24 h. E2 (1nM) increased LCN2 mRNA (p<0.01) and protein (p<0.05) levels by∼3 fold in AT, which was reversed by ERβ antagonist. Notably, E2 in presence of MPP induced LCN2 mRNA by 6 fold (p<0.05) compared to control. Likewise, ERβ agonist also induced LCN2 mRNA by 3.5 fold (p<0.05). Next, E2 induced ERβ mRNA by 1.8 fold (p<0.05), but not ERα mRNA or protein levels. Dex alone did not change LCN2 mRNA levels in AT from post-menopausal females. Dex reduced ERα mRNA and protein levels by 20% (p<0.001) and 35% (p<0.01), respectively, but increased ERβ mRNA by 220% (p<0.001). Dex-induced reduction in ERα mRNA levels was associated with BMI (r=0.569, p<0.01), waist circumference (r=0.565, p<0.01), fasting insulin (r=0.531, p<0.05) and c-peptide (r=0.560, p<0.01). In multivariate analysis BMI (std β coefficient = 0.626, p < 0.01; model: r 2 = 0.392) remained as significantly associated variable. In summary, E2 induced LCN2 expression in SCAT of postmenopausal women and this may be mediated via ERβ. Dex stimulation and inhibition of ERα and ERβ respectively implies a selective glucocorticoid mechanism to promote ERβ mediated transcriptional pathways. Overall, our data suggest that ERβ pathway may promote LCN2 expression and hence insulin resistance in AT. Disclosure P.G. Kamble: None. M.J. Pereira: None. G.J. Boersma: None. K.E. Almby: None. J.W. Eriksson: Employee; Spouse/Partner; Amgen Inc.. Consultant; Self; AstraZeneca. Research Support; Self; AstraZeneca. Consultant; Self; Novo Nordisk A/S, Merck Sharp & Dohme Corp.. Research Support; Self; Bristol-Myers Squibb Company.

Nanostructured gold dsDNA sensor for early detection of breast cancer by beta protein 1 (BP1)

Beta protein 1 (BP1) is a homeobox protein expressed in 80% of breast cancer cells in either estrogen receptor (ER) positive or ER negative breast cancer. However, it is barely detectable in normal breast tissues. In this project we present an electrochemical DNA nanostructured gold biosensor for detection of BP1. The gold sensor is first electrochemically nanostructured in 0.5M sulfuric acid to reach superior conductivity, larger surface area, and higher stability. Nanostructured gold surface was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The nanostructured gold sensor is then modified with double-stranded (ds) DNA mapping the genomic sequence that contains the binding site for BP1. A redox-active probe (methylene blue) was intercalated in dsDNA to monitor the binding event of BP1. A linear correlation of the electrochemical response by concentration of BP1 was obtained (R2=0.998) with a limit of detection of 1.2nM. This nanostructured gold dsDNA sensor is shown to be sensitive, selective, stable, and reusable allowing for its potential clinical use.

JS4-4 - Personalized Medicine in Endocrine Therapy for Breast Cancer Based on the Type of Resistant Mechanism

Endocrine therapy was most widely used modality for breast cancer patients. Basically, expression of either Estrogen Receptor (ER) or Progesterone Receptor (PR) predicts the response to therapy, its positive predictive value seems to be around 50-60%. In addition, so called “acquired resistance (secondary resistance)”, which is the development of resistance during long-term single endocrine therapy, has been important research issue. Simultaneous use of molecular targeting dug such as mTOR inhibitor or PI3K pathway inhibitor with second endocrine therapy could be important strategy for this acquired resistance. Although at this moment there is no companion assay for evaluating the molecular mechanism of acquired resistance in real time manner, we try to imagine the type of resistance from patient treatment history. Obviously the assay for this purpose should be urgent research target probably developed with liquid biopsy.In this session, we would review the current understanding of primary and secondary resistance, and try to figure out the way for personalized medicine in endocrine therapy.

Vascular measurements correlate with estrogen receptor status

BackgroundBreast carcinoma can be classified as either Estrogen Receptor (ER) positive or negative by immunohistochemical phenotyping, although ER expression may vary from 1 to 100% of malignant cells within an ER + tumor. This is similar to genetic variability observed in other tumor types and is generally viewed as a consequence of intratumoral evolution driven by random genetic mutations. Here we view cellular evolution within tumors as a classical Darwinian system in which variations in molecular properties represent predictable adaptations to spatially heterogeneous environmental selection forces. We hypothesize that ER expression is a successful adaptive strategy only if estrogen is present in the microenvironment. Since the dominant source of estrogen is blood flow, we hypothesized that, in general, intratumoral regions with higher blood flow would contain larger numbers of ER + cells when compared to areas of low blood flow and in turn necrosis.MethodsThis study used digital pathology whole slide image acquisition and advanced image analysis algorithms. We examined the spatial distribution of ER + and ER- cells, vascular density, vessel area, and tissue necrosis within histological sections of 24 breast cancer specimens. These data were correlated with the patients ER status and molecular pathology report findings.ResultsANOVA analyses revealed a strong correlation between vascular area and ER expression and between high fractional necrosis and absent ER expression (R2 = 39%; p < 0.003 and R2 = 46%; p < 0.001), respectively). ER expression did not correlate with tumor grade or size.ConclusionWe conclude that ER expression can be understood as a Darwinian process and linked to variations in estrogen delivery by temporal and spatial heterogeneity in blood flow. This correlation suggests strategies to promote intratumoral blood flow or a cyclic introduction of estrogen in the treatment schedule could be explored as a counter-intuitive approach to increase the efficacy of anti-estrogen drugs.

Estrogen modulates cardiac growth through an estrogen receptor α-dependent mechanism in healthy ovariectomized mice

The modulation of cardiac growth by estrogen in healthy mice is not completely understood. The aim was to investigate the effects of estrogen on cardiac growth in healthy mice lacking either estrogen receptor (ER) α or β. Wild-type (WT), ERα knockout (ERKO) and ERβ knockout (BERKO) 2-month-old mice were ovariectomized and randomly assigned to groups receiving an estradiol (E2)-containing or soy-free (control, CON) diet (n=5–7/group). After three months of E2 administration, WT and BERKO mice had significantly lower body weight, higher relative uterus and heart weight than CON mice, while there was no major E2 effect in ERKO mice. Furthermore, there was a higher concentration of E2-responsive genes Igf1 and Myocd in WT and BERKO but not in ERKO mice. Together, these findings indicate that the estrogenic regulation of cardiac growth in healthy mice is primarily mediated through ERα and not ERβ.

Abstract 516: VDR overexpression restores tamoxifen responsiveness.

Abstract Breast cancer is classified as either Estrogen Receptor (ER) positive or ER negative, depending on the presence or absence of the ERα. Approximately, 70% of breast cancers express ERα, with tamoxifen being the most commonly used treatment. However, prolonged treatment often results in the development of acquired resistance, which has presented a major challenge in development of more effective therapeutics for breast cancer. While many studies have focused on understanding the mechanisms behind the development of tamoxifen resistance, few have been successfully implemented into clinical practice. To mimic acquired resistance, we have established a tamoxifen-resistant cell line by treating MCF-7 cells with tamoxifen over prolong period of time in order to select for the resistant phenotype. Our lab has preliminary data that suggest that the Vitamin D receptor (VDR) is downregulated in tamoxifen-resistant breast cancer cells (MCF-7TamR) when compared to the parental MCF-7 cells. The role of VDR in tamoxifen resistance is unclear; however our preliminary data suggest that tamoxifen resistant cells transfected with a VDR overexpression plasmid displayed decrease cell proliferation when treated with tamoxifen in comparison to cells transfected with an empty vector, suggesting that restoring VDR expression may restore tamoxifen responsiveness. Data from this study will give us a better understanding about the role of VDR in the development of acquired resistance. Citation Format: Maggie C. Louie, Johnny Laim. VDR overexpression restores tamoxifen responsiveness. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 516. doi:10.1158/1538-7445.AM2013-516

Protein tyrosine phosphatase 4A2 expression predicts overall and disease-free survival of human breast cancer and is associated with estrogen and progestin receptor status.

Expression of protein tyrosine phosphatase PTP4A2 (also known as PRL2) has been examined in a variety of human carcinomas, although its role in breast cancer remains inconclusive. Since the majority of previous breast cancer studies utilized tissue biopsies composed of heterogeneous cell populations, we hypothesized that an examination of PTP4A2 expression in carcinoma cells isolated by laser capture microdissection (LCM) would provide a more accurate means of assessing its predictive value. From investigations of 247 human breast cancer biopsies collected under standardized, stringent conditions, total RNA was extracted from LCM-procured carcinoma cells to perform microarray analyses to identify gene signatures associated with breast cancer behavior. Expression of PTP4A2 was corroborated by real-time quantitative polymerase chain reaction (qPCR) and referenced to estrogen and progesterone receptor levels. Patient outcomes for overall and disease-free survival were more favorable (p = 0.004 and p = 0.001, respectively) when the expression of PTP4A2 in breast carcinomas was increased compared to patients with biopsies with decreased PTP4A2 levels. PTP4A2 expression determined either by microarray or qPCR was elevated in either estrogen receptor (ER)-positive or progestin receptor (PR)-positive breast cancer biopsies compared to ER-negative or PR-negative biopsies. However, PTP4A2 expression was only correlated with overall survival in PR-positive breast carcinomas. These data suggest that PTP4A2 mRNA expression alone may serve as a biomarker for prediction of a breast cancer patient's risk of recurrence and overall survival.

Elevated Transcription of the Gene QSOX1 Encoding Quiescin Q6 Sulfhydryl Oxidase 1 in Breast Cancer

The q arm of chromosome 1 is frequently amplified at the gene level in breast cancer. Since the significance of this is unclear we investigated whether 1q genes are overexpressed in this disease. The cDNA levels of 1q-located genes were analysed in a search for overexpressed genes. 26 genes mapping to the 1q arm show highly significant (P≤0.01) overexpression of transcripts in breast cancer compared to normal breast tissue. Amongst those showing the highest levels of overexpression in both expressed sequence tag (EST) and serial analysis of gene expression (SAGE) databases was enzyme quiescin Q6 sulfhydryl oxidase 1 (QSOX1). We investigated QSOX1 cDNA derived from T47D breast carcinoma cells by RT-PCR and 3′-RACE PCR and identified a novel extended form of QSOX1 transcript, containing a long 3′UTR, nearly double the size of the previously reported QSOX1 cDNA, and confirmed its 3′ end nucleotide sequence using RACE-PCR. We also used quantitative real-time PCR to analyse a panel of cDNAs derived from 50 clinically-graded normal and malignant breast tissue samples for the expression of QSOX1 mRNAs. QSOX1 transcription was elevated in an increasing proportion in the grade 2 and grade 3 tumours (graded according to the Nottingham prognostic index), with 10 of the 15 grade 3 tumours (67%) examined exceeding the normal range. There was a significant correlation between relative transcript level and clinical grade (P≤0.01) for all qPCR primer sets tested. QSOX1 mRNA levels, based on SAGE expression data, did not correlate with either Estrogen Receptor (ER) or Epidermal Growth Factor Receptor 2 (ErbB-2 or HER2/neu) expression. Our data indicate that QSOX1 is a potential new prognostic marker which may prove of use in the staging of breast tumours and the stratification of breast cancer patients.

Comparison of Radiologic Features of Triple-Negative and Estrogen Receptor/Progesteron Receptor Positive Breast Cancer

This work was supported in part by Konyang University Myeonggok Research Fund of 2010. Purpose: To retrospectively investigate the imaging [mammographic, ultrasonographic (US), magnetic resonance (MR) imaging] features and standardized uptake values (SUV) in positron emission tomography (PET)/computed tomography (CT) of triple-negative breast cancers (TNBC) and to compare them with breast cancers that are either estrogen receptor (ER) positive or progesteron receptor (PR) positive. Materials and Methods: 155 breast cancers cases were identified in 134 women (mean age, 51 years; range, 31-86 years). Surgically confirmed TNBC (n = 27) and ERpositive/PR-positive breast cancers (n = 81) were included among them. Cancers were investigated with mammography (n = 81), US (n = 106), MR imaging (n = 34) and PET-CT (n = 59). Mammographic findings are identified by detection of characteristic masses and microcalcifications. US findings included tumor size, margin, tumor shape, calcification and posterior shadowing. MR findings included tumor size, shape, margin, internal enhancement, intratumoral signal intensity and kinetics. Peak SUVs (p-SUV) of breast cancers were evaluated in PET/CT. These findings were compared with TNBC and ER/PR positive groups. Results: Mammographic findings had no significant association with the TNBC. High pathological grade (p < 0.05), larger than 2 cm in size, well-marginal mass, and round or oval-shaped (p < 0.05) is US were significantly associated with TNBC. In MR imaging, round mass shape (p < 0.05), well-circumscribed mass margin (p < 0.05), rim enhancement (p < 0.05), were significantly associated with TNBC. The peak SUV of TNBC tend to be higher than that of ER-positive/PR-positive breast cancer (7.95 ± 5.50 vs. 4.91 ± 3.00, p < 0.05). Conclusion: TNBC tend to have high pathological grade, are of a large, round and smooth mass with rim enhancement on MR and US. In addition to above features, PET-CT with SUV estimation can improve the accuracy of test through the evaluation of TNBC. Index terms Breast Malignancy MRI Positron Emission Tomography-CT Ultrasound Mammography Comparison of Radiologic Features of Triple-Negative and Estrogen Receptor/Progesteron Receptor Positive Breast Cancer 삼중음성 유방암과 Estrogen Receptor/Progesteron Receptor 양성 유방암의 영상의학적 소견 비교

Lack of Either Estrogen or Progesterone Receptor Expression Is Associated with Poor Survival Outcome among Luminal A Breast Cancer Subtype

This study was designed to evaluate the impact of lack of either estrogen receptor (ER) or progesterone receptor (PR) on characteristics and outcomes among luminal A breast cancer subtype treated with endocrine with or without chemotherapeutic agents. The luminal A subtype was categorized into three subgroups: ER+/PR+, ER+/PR-, and ER-/PR+. All tumors were human epidermal growth factor receptor 2 (HER2) negative. Clinicopathological features and survival were analyzed using the Severance Hospital dataset (n = 1,180) and were validated by the nationwide Korean Breast Cancer Society (KBCS) registry (n = 9,916). Despite the different distribution of ER/PR status, tumor stage, grade, and local therapies between the two datasets, similarly ER+/PR+ showed smaller size and good differentiation, ER+/PR- patients had the oldest age at diagnosis, and ER-/PR+ was associated with the youngest age at onset and grade III tumor. Single hormone receptor-positive subgroups demonstrated worse disease-related outcomes than the ER+/PR+ subgroup. These associations were confirmed by the KBCS dataset. This trend was also demonstrated in the subpopulation of 1,944 patients with Ki-67 < 14 %. Inferior survival of single receptor-positive tumors was more definite among node-positive patients even when receiving both chemo-endocrine therapies. Current results suggest that the luminal A subtype is also heterogeneous and each subgroup has unique clinicopathologic characteristics. Lack of either ER or PR expression is associated with worse survival, especially among node-positive luminal A subtype.

Sexual responses of the male rat medial preoptic area and medial amygdala to estrogen II: Site specific effects of selective estrogenic drugs

In the medial preoptic area (MPO) and medial amygdala (MEA), estradiol (E2) aromatized from testosterone (T) may act via either estrogen receptor (ER) α or ERβ to mediate mating in male rats. We tested the hypothesis that, in the MPO, ERα exclusively mediates sexual responses to E2 by monitoring mating in four groups of castrated male rats administered dihydrotestosterone (DHT) subcutaneously and MPO implants delivering either: cholesterol, E2, propyl pyrazole triol (PPT, ERα-agonist) or diarylpropionitrile (DPN, ER β-agonist); a fifth group of intact males served as DPN toxicity control, receiving DPN MPO implants. In a follow-up study, either 1-methyl-4-phenyl pyridinium (MPP, ERα-antagonist) or blank MPO cannulae were implanted in castrated male rats receiving T subcutaneously, whereas intact MPP toxicity controls received MPP MEA implants. PPT or E2 MPO implants maintained mating, but cholesterol or DPN MPO implants did not. Moreover, MPP MPO implants interfered with T reinstatement of mating suggesting that, in the MPO, ERα is necessary and sufficient for mating in androgen-maintained male rats and ERβ is not sufficient. Because it is unknown which ER subtype(s) mediate sexual responses of the MEA to E2, we examined mating following MEA implants of cholesterol, E2, PPT or DPN in four groups of castrated male rats administered DHT subcutaneously. E2 MEA implants maintained mounting but mating was significantly decreased in groups receiving PPT, DPN or cholesterol MEA implants suggesting that, unlike the MPO where ERα alone is essential, sexual responses of the MEA to E2 require simultaneous interactions among multiple ER subtypes.

Estrogen treatment prevents gray matter atrophy in experimental autoimmune encephalomyelitis

Gray matter atrophy is an important correlate to clinical disability in multiple sclerosis (MS), and many treatment trials include atrophy as an outcome measure. Atrophy has been shown to occur in experimental autoimmune encephalomyelitis (EAE), the most commonly used animal model of MS. The clinical severity of EAE is reduced in estrogen-reated mice, but it remains unknown whether estrogen treatment can reduce gray matter atrophy in EAE. In this study, mice with EAE were treated with either estrogen receptor (ER)-α ligand or ER-β ligand, and diffusion tensor images (DTI) were collected and neuropathology was performed. DTI showed atrophy in the cerebellar gray matter of vehicle-treated EAE mice compared with healthy controls but not in ER-α or ER-β ligand-treated EAE mice. Neuropathology demonstrated that Purkinje cell numbers were decreased in vehicle-treated EAE mice, whereas neither ER ligand-treated EAE groups showed a decrease. This is the first report of a neuroprotective therapy in EAE that unambiguously prevents gray matter atrophy while sparing a major neuronal cell type. Fractional anisotropy (FA) in the cerebellar white matter was decreased in vehicle- and ER-β ligand-treated but not in ER-α ligand-treated EAE mice. Inflammatory cell infiltration was increased in vehicle- and ER-β ligand-treated but not in ER-α ligand-treated EAE mice. Myelin staining was decreased in vehicle-treated EAE mice and was spared in both ER ligand-treated groups. This is consistent with decreased FA as a potential biomarker for inflammation rather than myelination or axonal damage in the cerebellum in EAE.

Spinal Synthesis of Estrogen and Concomitant Signaling by Membrane Estrogen Receptors Regulate Spinal κ- and μ-Opioid Receptor Heterodimerization and Female-Specific Spinal Morphine Antinociception

We previously demonstrated that the spinal cord κ-opioid receptor (KOR) and μ-opioid receptor (MOR) form heterodimers (KOR/MOR). KOR/MOR formation and the associated KOR dependency of spinal morphine antinociception are most robust during proestrus. Using Sprague Dawley rats, we now demonstrate that (1) spinal synthesis of estrogen is critical to these processes, and (2) blockade of either estrogen receptor (ER) α-, β-, or G-protein-coupled ER1 or progesterone receptor (PR) substantially reduces KOR/MOR and eliminates mediation by KOR of spinal morphine antinociception. Effects of blocking ERs were manifest within 15 min, whereas those of PR blockade were manifest after 18 h, indicating the requirement for rapid signaling by estrogen and transcriptional effects of progesterone. Individual or combined blockade of ERs produced the same magnitude of effect, suggesting that they work in tandem as part of a macromolecular complex to regulate KOR/MOR formation. Consistent with this inference, we found that KOR and MOR were coexpressed with ERα and G-protein-coupled ER1 in the spinal dorsal horn. Reduction of KOR/MOR by ER or PR blockade or spinal aromatase inhibition shifts spinal morphine antinociception from KOR dependent to KOR independent. This indicates a sex steroid-dependent plasticity of spinal KOR functionality, which could explain the greater analgesic potency of KOR agonists in women versus men. We suggest that KOR/MOR is a molecular switch that shifts the function of KOR and thereby endogenous dynorphin from pronociceptive to antinociceptive. KOR/MOR could thus serve as a novel molecular target for pain management in women.

Resection of liver metastases from breast cancer: Effect of timing of surgery and estrogen receptor status on outcome.

288 Background: The oncologic benefit of resecting liver metastases (LM) in breast cancer patients is unclear. Identifying predictors of improved outcome would be useful in selecting appropriate candidates for surgery. Methods: From 1997 to 2010, 86 breast cancer patients underwent LM resection. RECIST criteria were used to define the best response to chemotherapy as the optimal response at any time during the course of metastatic disease and the preoperative response to chemotherapy as the response immediately before LM resection. Univariate and multivariate analyses were used to identify predictors of survival. Results: Sixty-four patients (74%) had primary tumors that were either estrogen receptor (ER) or progesterone receptor (PR) positive. Fifty-three patients (62%) had solitary LM, and 73 patients (85%) had LM smaller than 5 cm. Sixty-five patients (76%) received preoperative chemotherapy, and 10 patients (12%) received 2 or more chemotherapy regimens before LM resection. Only 2 patients (3%) had progressive disease (PD) as a best response to chemotherapy, whereas 19 patients (29%) had PD as preoperative response to chemotherapy (p &lt; 0.001). No perioperative mortality was observed. At a median follow-up of 62 months, the median durations of overall and disease-free survival were 57 and 14 months. Univariate analysis revealed that ER and PR primary tumor status, best response to chemotherapy, and preoperative response to chemotherapy were associated with overall survival after LM resection. On multivariate analysis, an ER-negative primary tumor (p=.009, hazard ratio [HR] = 3.3, 95% confidence interval [CI] =1.4-8.2) and preoperative disease progression (p=.003, HR = 3.8, 95% CI = 1.6-9.2) were independently associated with worse survival after LM resection. Conclusions: Resection of liver metastases in breast cancer patients with ER positive disease that is responsive to chemotherapy is associated with prolonged survival. Timing of surgery is critical and resection before progression is associated with better outcome. No significant financial relationships to disclose.

Abstract 4889: Transforming growth factor-β signaling in breast cancer subtypes

Abstract Transforming growth factor β (TGF-β) plays a dual role in breast cancer (BC), acting as a tumor suppressor during the early stages of tumor development and assuming a prometastatic role, enhancing invasion and metastasis during the later stages of progression. This inherent complexity of TGF-β signaling in BC prompted us to characterize the TGF-β signaling pathway as a function of BC subtype. For this purpose, we used a panel of human BC cell lines that were either estrogen receptor (ER) positive (luminal) or -negative (basal-like) and either HER2 positive or -negative. Both luminal and basal-like cell lines secreted bioactive TGF-β, as determined by activation of the PAI-1 promoter (PAI-1pr) in PAI-1pr-LUC transfected mink lung epithelial cells (TMLC). Nonetheless, we had previously found that basal-like BC cell lines typically express a TGF-β response gene signature (TBRS), while luminal cell lines do not. Consistent with this observation, treatment with exogenous TGF-β induced phosphorylation of Smad2/3 in the ER-negative but not in ER-positive cells. Furthermore, we found a striking inverse correlation between the level of ER-alpha and TGF-β receptor II (TβRII) transcripts. Whereas basal-like cell lines typically expressed high levels of TβRII mRNA, luminal lines uniformly lacked TβRII expression. These results were confirmed by multiplex qRT-PCR. It has been shown previously that treatment of ER-positive BC cell lines with estradiol suppresses their production of TGF-β, while treatment with anti-estrogens such as tamoxifen increases the level of secreted TGF-β. In fact, it has been proposed that induction of TGF-β by tamoxifen might mediate its anti-tumor effects against ER-positive BC. However, our results essentially exclude the possibility that tamoxifen-induced growth inhibition is mediated by autocrine effects of TGF-β, as the tamoxifen-responsive BC cell lines are intrinsically unresponsive to TGF-β. On the other hand, TGF-β may mediate tamoxifen-resistance, as previous studies have shown that treatment of tumor bearing mice with a TGF-β neutralizing antibody could overcome resistance to tamoxifen. Moreover, recent studies indicate that both tamoxifen-and fulvestrant-resistant MCF-7 cell variant express high levels of TGF-β pathway genes, including TβRII. Therefore, we examined the mechanism of TβRII gene silencing in luminal BC lines. Treatment of ER-positive cell lines with 5-Aza-deoxycytidine alone, Trichostatin-A alone or a combination of both, resulted in a significant induction of TβRII mRNA expression in cells treated with both agents. These findings suggest that TβRII gene silencing in luminal BC cell lines is the result of both DNA methylation and histone deacetylation. We are currently investigating the possibility that re-expression of TβRII mRNA might sensitize luminal BC cells to treatment with anti-estrogens, TGF-β antagonists or a combination of the two modalities. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4889.

Lasofoxifene, a new selective estrogen receptor modulator for the treatment of osteoporosis and vaginal atrophy

Selective estrogen receptor modulators (SERMs) represent a class with a growing number of compounds that act as either estrogen receptor (ER) agonists or antagonists in a tissue-specific manner. The purpose of this article is to review the effects of lasofoxifene, a new-generation SERM that has completed the Phase III development program for the prevention and treatment of osteoporosis and vaginal atrophy in postmenopausal women. This compound selectively binds to both ERs with high affinity. Lasofoxifene also has a remarkably improved oral bioavailability with respect to other SERMs such as raloxifene and tamoxifen, owing to increased resistance to intestinal wall glucuronidation. In both preclinical and short-term clinical studies, this compound showed a favorable safety profile and demonstrated a proven efficacy in preventing bone loss and lowering cholesterol levels. More recently, Phase III clinical trials have confirmed the efficacy and safety of this new SERM in the prevention of bone loss and vertebral and nonvertebral fractures. Moreover, in postmenopausal women with osteoporosis, lasofoxifene treatment also reduced ER positive breast cancer risk and the occurrence of vaginal atrophy. With its increased potency and efficacy on the prevention of nonvertebral fractures and its positive effects on the vagina, this new SERM may represent an alternative therapy for osteoporosis in postmenopausal women.

Metabolism-perfusion mismatch as assessed by PET varies with breast cancer phenotype and predicts response to neoadjuvant chemotherapy.

Abstract Abstract #6005 Background: Kinetic analysis of FDG and water PET can identify patterns of breast cancer metabolism and perfusion in patients receiving neoadjuvant chemotherapy (NC). Previously, we found that high pre-therapy glucose tumor metabolism relative to perfusion was associated with poor tumor pathologic response, early relapse, and death in patients with locally advanced breast cancer (LABC) treated with NC. This analysis examines tumor metabolism and perfusion as a function of tumor phenotype. Material and Methods: Tumor phenotype, defined by immunohistochemistry (IHC), was determined in 51 patients undergoing NC between 1995 and 2005. Luminal tumors were defined as those expressing either estrogen receptor (ER) or progesterone receptor (PR). The triple-negative (TN) phenotype was defined as ER and PR negative without HER2 overexpression by IHC or amplification by FISH. HER2 phenotype showed HER2 overexpression or amplification but were ER/PR negative. Women with LABC underwent dynamic [18F]-FDG and [15O]-water PET scans prior to NC. The FDG metabolic rate (MRFDG) and transport (FDG K1) parameters were calculated; blood flow (BF) was estimated from the water PET scan. Response to NC was determined from surgical specimens with pathologic complete response (pCR) defined as eradication of invasive tumor in the breast vs. other. Results: Of the tumors studied, 16 (31%) were TN, 30 (59%) were luminal, and 5 (10%) were HER2. pCR was observed in 4/16 (25%) TN tumors (95% CI: 0.10-0.50) compared to only 4/30 (13%) of luminal tumors (95% CI: 0.05-0.30) and 3/5 HER2 tumors. Linear regression of the association between PET parameters and phenotype (TN vs. luminal) found that TN was associated with higher MRFDG (p=0.007) and MRFDG/BF ratio (p=0.02), but not with BF (p=0.27). Only patients with low pre-therapy MRFDG/BF ratio (&amp;lt;35 umol/mL) achieved a pCR. Using this value as an ad-hoc cutoff, 4/7 (57%) of TN patients with low ratios had a pCR, while 0/9 with higher ratios had pCR. In contrast, only 4/21 (19%) of the luminal patients with low ratios had a pCR (one-sided mid-p=0.04 for TN vs. luminal pCR rate for patients with MRFDG/BF &amp;lt; 35 umol/mL). Discussion: These results demonstrate heterogeneity in breast tumor metabolism and perfusion as assessed by PET, and suggest a clinically relevant association between PET parameters and tumor phenotypes. The high MRFDG/BF ratio that predicts poor response to NC is more common in TN tumors; whereas in luminal or HER2 tumors, high MRFDG is generally matched with higher BF. Measurement of tumor metabolism and perfusion may identify a subset of tumors which are unlikely to respond to NC. Identification of such tumors may direct therapy toward those biologic targets most likely to overcome resistance. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6005.

Abstract A128: Protective effects of nexrutine, a phellodendron amurense extract, against breast cancer is associated with autophagy.

Abstract A128 Breast cancer is the most frequent cancer in women with over 40,000 deaths per year in the United States. The prognosis for a subset of these women with breast tumors that are either estrogen receptor (ER)-negative or ER- and overexpress ErbB2 (also known as HER2/Neu) is very poor because these tumor are aggressive and do not respond to standard treatments. This situation emphasizes the importance of developing new agents and protocols for preventing breast cancer. Numerous epidemiological studies suggest that plant-based diets are protective against many types of cancer. However, there is very little known about many of these botanicals for preventing breast cancer. Nexrutine is an herbal extract from the Chinese tree phellodendron amurense that has been used over hundreds of years in traditional Chinese medicine for treatment of inflammation, gastroenteritis, abdominal pain, and diarrhea. Numerous studies indicate a relationship between inflammation and cancer. In particular, many studies have reported that breast tumors have increased expression of cyclooxygenase (COX-2), the rate-limiting enzyme that controls the conversion of arachidonic acid into pro-inflammatory prostaglandins (PG). High levels of PGE2 in breast tumors are associated with increased proliferation, metastasis, resistance to apoptosis, and angiogenesis. Overexpression of COX-2 occurs more frequently in DCIS, which suggests that COX/PG is an important target for preventing the progression of DCIS to metastic breast cancer. However, considering the recent concerns of the cardiovascular risks associated with the COX-2 inhibitor drugs, there is an urgent need to develop nontoxic approaches to target the PGE pathway. Targeting PGE2 synthese and 15-hydroxy PG dehydrogenase (15-PGDH) provides an alternative strategy to block PGE2 without the risk the cardiovascular risks. SkBr3, MDA-MB 231, and BT474 cells were treated with nexrutine for 24, 48, and 72 h. Nexrutine produced a time and concentration decrease in cell survival, which was accompanied by a G0/G1 cell cycle arrest and decreased protein expression of cyclin D1. nexrutine reduced the production of PGE2 without altering PGI2. The reducing in PGE2 levels was associated with decreased protein expression of PGE2 synthase and increased 15-PGDH. Peroxisome proliferators-activated receptor (PPAR) γ is also increased in many cancers including breast. Recent studies have suggested that PPAR γ may function as a tumor promoter gene. Upregulation of PPAR γ has been demonstrated in ER- breast cancer tumors and may be a marker for reoccurrence of DCIS. We show that nexrutine decreased activation of PPAR γ. Nexrutine reduced protein levels of PPAR γ and activation of PPAR γ. Growth inhibitory effects of nexrutine were associated with increased PTEN and Beclin 1 protein expression, and type-2 cell death known as autophagy. Based upon these findings, we propose that the use of nexrutine could provide a novel approach for protection against breast cancer. Citation Information: Cancer Prev Res 2008;1(7 Suppl):A128.