scholarly journals Inhibition of estrogen receptor signaling

2005 ◽  
Vol 8 (3) ◽  
Author(s):  
E. M. Rosen ◽  
S. Fan
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Estrogen Receptor Alpha ◽  
Dietary Factors ◽  
Type I ◽  
Breast Cancers ◽  
Human Breast ◽  
Estrogen Receptor Signaling ◽  
Reduce Breast Cancer Risk ◽  
Pharmacologic Agents

The estrogen receptor-alpha (ER-α) is a Type I nuclear receptor that is over-expressed in the majority of human breast cancers and plays a significant role in the development and progression of these cancers. As estrogen plays important roles in the etiology of breast cancer and the growth of established ER-α expressing cancers, intense interest has been generated in understanding the mechanisms by which ER-α signaling is regulated physiologically and using this knowledge to develop interventions to inhibit ER-α signaling. These efforts have met with some success in the development of pharmacologic agents that can reduce breast cancer risk, prevent recurrence of established cancers, and treat advanced cancers with considerably less side effects than cytotoxic chemotherapy. Here, we will review some of the mechanisms that operate to inhibit ER-α signaling and describe how pharmacologic agents and dietary factors interact with ER-α to block its activity. In the process of reviewing these mechanisms, we will highlight their clinical implications.

scholarly journals Estrogen receptor coregulator binding modulators (ERXs) effectively target estrogen receptor positive human breast cancers

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Ganesh V Raj ◽  
Gangadhara Reddy Sareddy ◽  
Shihong Ma ◽  
Tae-Kyung Lee ◽  
Suryavathi Viswanadhapalli ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Protein Interactions ◽  
Human Breast Cancer ◽  
Estrogen Receptor Alpha ◽  
Breast Cancers ◽  
Human Breast ◽  
Oncogenic Signaling ◽  
Estrogen Receptor Positive ◽  
Orally Bioavailable

The majority of human breast cancer is estrogen receptor alpha (ER) positive. While anti-estrogens/aromatase inhibitors are initially effective, resistance to these drugs commonly develops. Therapy-resistant tumors often retain ER signaling, via interaction with critical oncogenic coregulator proteins. To address these mechanisms of resistance, we have developed a novel ER coregulator binding modulator, ERX-11. ERX-11 interacts directly with ER and blocks the interaction between a subset of coregulators with both native and mutant forms of ER. ERX-11 effectively blocks ER-mediated oncogenic signaling and has potent anti-proliferative activity against therapy-sensitive and therapy-resistant human breast cancer cells. ERX-11 is orally bioavailable, with no overt signs of toxicity and potent activity in both murine xenograft and patient-derived breast tumor explant models. This first-in-class agent, with its novel mechanism of action of disrupting critical protein-protein interactions, overcomes the limitations of current therapies and may be clinically translatable for patients with therapy-sensitive and therapy-resistant breast cancers.

scholarly journals Regulatory Interplay between miR-181a-5p and Estrogen Receptor Signaling Cascade in Breast Cancer

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 543
Author(s):  
Rosaria Benedetti ◽  
Chiara Papulino ◽  
Giulia Sgueglia ◽  
Ugo Chianese ◽  
Tommaso De Marchi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Endocrine Therapy ◽  
Mirna Expression ◽  
Estrogen Receptor Alpha ◽  
Estrogen Signaling ◽  
Integrated Analysis ◽  
Tumor Resistance ◽  
Estrogen Receptor Signaling

The efficacy and side effects of endocrine therapy in breast cancer (BC) depend largely on estrogen receptor alpha (ERα) expression, the specific drug administered, and treatment scheduling. Although the benefits of endocrine therapy outweigh any adverse effects in the initial stages of BC, later- or advanced-stage tumors acquire resistance to treatments. The mechanisms underlying tumor resistance to therapy are still not well understood, posing a major challenge for BC patient care. Epigenetic regulation and miRNA expression may be involved in the switch from a treatment-sensitive to a treatment-resistant state and could provide a valid therapeutic strategy for ERα negative BC. Here, a hybrid lysine-specific histone demethylase inhibitor, MC3324, displaying selective estrogen receptor down-regulator-like activities in BC, was used to highlight the interplay between epigenetic and ERα signaling. MC3324 anticancer action is mediated by microRNA (miRNA) expression regulation, indicating an innovative function for this molecule. Integrated analysis suggests a crosstalk between estrogen signaling, ERα interactors, miRNAs, and their putative targets. Specifically, miR-181a-5p expression is regulated by MC3324 and has an impact on cellular levels of ERα. A comparison of breast tumor versus healthy mammary tissues confirmed the important role of miR-181a-5p in ERα regulation and points to its putative predictive function in BC therapy.

A novel therapeutic strategy for ER-negative human breast cancers, targeting AP-1 activity

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 14129-14129
Author(s):  
K. Sakaguchi ◽  
H. Nakajima ◽  
I. Fujiwara ◽  
N. Mizuta ◽  
J. Magae
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cell Lines ◽  
Cancer Cell ◽  
Breast Cancer Cell ◽  
Human Breast Cancer ◽  
Human Breast Cancer Cell ◽  
Breast Cancers ◽  
Human Breast ◽  
Er Positive

14129 Background: While agents targeting estrogen receptors are the most effective in adjuvant therapy for human breast cancers expressing estrogen receptor(ER), breast cancers lacking ER are clinically serious, because they are highly malignant and exhibit resistance to the usual anti-cancer drugs, including estrogen receptor-antagonists and DNA breaking agents. Although a transcription factor, AP-1, is known to be related to tumor malignancy including metastasis, invasion and drug-resistance, it remains to be elucidated how AP-1 plays in development and expression of malignant characters of human breast cancers. Methods and Results: Here, we used MX-1, a human breast cancer cell line lacking ER and several ER positive cell lines, to clarify the roles of AP-1 and the therapeutic efficacy of ascochlorin, a newly developed prenylphenol antibiotic on ER-negative breast cancer. We found that MX-1 exhibited higher AP-1 activity and expressed higher levels of c-Jun, c-Fos and Fra-1 when compared with conventional ER-positive human breast cancer cell lines. Consistent with this study in vitro, histological study on human breast cancer tissues suggests that ER-negative cancers express high Fra-1 protein, and that paclitaxel- sensitive cancers express low Fra-1 protein. The ascochlorin, which inhibits AP-1 through the Erk signaling pathway, suppressed the AP-1 activity of MX-1 cells, and selectively killed MX-1 cells, partly due to induction of apoptosis. Moreover, administration of ascochlorin elongated life span of mice intraperitoneally implanted with murine mammary carcinoma cells. Conclusions: Our results suggest that AP-1 is an effective clinical target molecule for the treatment of ER-negative human breast cancer, and that ascochlorin is promising therapeutic agent for these refractory breast cancers. No significant financial relationships to disclose.

Jab1 and estrogen receptor alpha (ERa) in human breast cancer

2008 ◽  
Vol 6 (9) ◽  
pp. 94-95
Author(s):  
A. Zuse ◽  
W. Weebadda ◽  
K. Ung ◽  
G. Skliris ◽  
L. Murphy
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Human Breast Cancer ◽  
Estrogen Receptor Alpha ◽  
Human Breast ◽  
Receptor Alpha

scholarly journals Role of P-53 Gene in Preventing Breast Cancer

2018 ◽  
Vol 3 (2) ◽  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Inflammatory Breast Cancer ◽  
Poor Prognosis ◽  
Triple Negative ◽  
Type I ◽  
Breast Cancers ◽  
T Helper ◽  
Tp53 Mutations ◽  
Her 2

Breast cancer affects more than one million patients annually in the world and is a leading cause of mortality. Histological type, grade, tumor size, lymph node involvement, and estrogen receptor and HER-2 receptor status, all influence prognosis and the probability of response to systemic therapies. P53 gene is mutated in about 30% of breast cancers/.The possible links between alterations of p53 and clinical or pathological features of breast tumors have been widely investigated. The first study to examine gene-expression patterns of breast cancer suggested that at least four major molecular classes of breast cancer exist: luminal-like, basal-like, normal like, and HER-2 positive. Basal-like breast cancer account for 15% of breast cancers and are often described as triple negative breast cancers (TNBCs). In fact, TNBCs, defined by lack of expression of estrogen receptor, progesterone receptor, and HER2, probably include both basal-like breast cancers and some poorly differentiated luminal breast cancers. They are also associated with a younger age and a poor prognosis. TNBCs also have an increased frequency of TP53 mutations. Recently, it was shown that mutant p53 status was a strongly unfavorable prognostic factor for relapse-free survival and overall survival only in a triple negative group in patients treated with adjuvant anthracycline-containing chemotherapy. Inflammatory breast cancer (IBC) is a clinical diagnosis known as the T4d category in the TNM classification. It is a distinct clinical subtype of locally advanced breast cancer (LABC), with a particularly aggressive behavior and poor prognosis. TP53 mutations are more frequent in inflammatory breast cancer (50%) than in non-inflammatory breast cancer (20–30%). The results from these studies served as the justification for attempts to vaccinate patients using p53-derived peptides, and a number of clinical trials are in progress. The most advanced work used a long synthetic peptide mixture derived from p53 (p53-SLP; Netherlands).The vaccine is delivered in the adjuvant setting and induces T helper type I response in the majority of patients. However, the response may not be potent enough to result in clinical benefit as a mono-therapy because most patients had T-helper cells that failed to produce key cytokines, indicating that this treatment should also be associated with another type of conventional or immunotherapy therapy.

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