ESR1 (Ab-537) Antibody
Description
Introduction to ESR1 (Ab-537) Antibody
Estrogen Receptor alpha (ESR1) functions as a nuclear hormone receptor involved in regulating eukaryotic gene expression and influencing cellular proliferation and differentiation in target tissues. The ESR1 (Ab-537) antibody specifically recognizes the region around the phosphorylation site of tyrosine 537 in human ESR1, which represents a critical regulatory domain within the ligand-binding region of the receptor .
This phosphorylation site has gained significant research attention due to its involvement in hormone-resistance mechanisms, particularly in breast cancer. The antibody enables researchers to detect both wild-type ESR1 and potentially differentiate mutated forms that contribute to endocrine therapy resistance .
Biological Significance of the Target Site
The tyrosine 537 residue resides within the ligand-binding domain (LBD) of ESR1 and represents one of the most commonly mutated sites in hormone-receptor positive breast cancers that develop resistance to endocrine therapy. Mutations at this position can constitutively activate the receptor in the absence of estrogen, thereby conferring resistance to standard endocrine therapies .
Applications and Methodological Considerations
The ESR1 (Ab-537) antibody demonstrates versatility across multiple experimental techniques, enabling comprehensive investigation of ESR1 expression and function.
Western Blotting
For Western blot applications, the antibody is typically used at dilutions ranging from 1:500 to 1:3000 . The target protein is detected at approximately 66-68 kDa, consistent with the calculated molecular weight of the ESR1 protein. Validation studies have confirmed specificity using 293 cells, where the antibody successfully detects endogenous levels of total Estrogen Receptor-α protein .
Immunohistochemistry
In immunohistochemistry applications on paraffin-embedded tissues (IHC-P), the recommended dilution range is 1:50 to 1:100 . The antibody has been validated on human lung carcinoma tissue, demonstrating specific nuclear staining patterns consistent with the expected subcellular localization of ESR1 . This application is particularly valuable for assessing ESR1 expression in clinical samples and tumor tissues.
ELISA Applications
While detailed protocols are not explicitly provided in the search results, the antibody is reported to be suitable for ELISA applications . This suggests utility in quantitative assessment of ESR1 protein levels in various experimental settings.
Role in Hormone-Resistant Breast Cancer
Research utilizing antibodies targeting the tyrosine 537 region has contributed significantly to understanding the mechanisms of endocrine resistance in breast cancer. Studies have demonstrated that mutations at positions 537 and 538 (particularly Y537S, Y537C, Y537N, and D538G) constitute approximately 85% of ESR1 gene mutations in breast cancer patients treated with hormone therapy .
These mutations have profound functional consequences:
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They promote estrogen receptor signaling in the absence of ligand (hormone-independent activation)
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They induce changes in receptor conformation that affect co-regulator recruitment
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They are associated with decreased sensitivity to standard endocrine therapies
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They correlate with poorer clinical outcomes in metastatic breast cancer
Immunogenicity of ESR1 Mutations
Recent research has explored the potential of ESR1 mutations to generate neoantigens that might be recognized by the immune system. Studies have identified several peptides derived from mutated ESR1 (including those with Y537S, Y537N, Y537C, and D538G mutations) that exhibit immunogenic properties .
Interestingly, these mutations may have dual effects on immune recognition:
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They can generate neoantigens potentially recognizable by T cells
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In advanced disease stages, they correlate with downregulation of antigen presentation machinery and reduced immune cell infiltration
This suggests a complex relationship between ESR1 mutations and immune surveillance that might be exploited for therapeutic purposes.
Comparative Analysis with Other ESR1 Antibodies
The ESR1 (Ab-537) antibody represents one of several approaches to detecting and studying the estrogen receptor. Other commercially available antibodies target different epitopes and exhibit varying characteristics.
Epitope Diversity in ESR1 Antibodies
While the ESR1 (Ab-537) antibody specifically targets the region around tyrosine 537, other antibodies target different regions:
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Antibodies targeting the central region: Some antibodies, like the one described in result , target peptides near the center of human ESR1 (amino acids 250-300), away from the ligand-binding domain .
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Antibodies targeting modification sites: The Anti-ESR1 Rabbit Polyclonal Antibody (catalog #10813-912) specifically recognizes the phosphorylated form of tyrosine 537 .
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Antibodies recognizing multiple species: The reactivity profile varies among antibodies, with some recognizing human, mouse, and rat ESR1, while others are more species-restricted .
This diversity enables researchers to select antibodies based on their specific experimental requirements and research questions.
Detection of ESR1 Mutations in Metastatic Breast Cancer
The ESR1 (Ab-537) antibody and related tools have facilitated research into the prevalence and significance of ESR1 mutations in metastatic breast cancer. Studies have revealed that mutations at position 537 occur in approximately 40% of hormone-resistant breast cancers, making them critical biomarkers for endocrine resistance .
Implications for Therapeutic Development
Understanding the structural and functional consequences of mutations at tyrosine 537 has informed the development of novel therapeutic strategies:
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Selective estrogen receptor degraders (SERDs) that may overcome resistance mutations
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Therapies targeting downstream signaling pathways activated by mutant ESR1
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Potential immunotherapeutic approaches targeting ESR1-derived neoantigens
Research utilizing the ESR1 (Ab-537) antibody has contributed to these developments by enabling detection and characterization of the mutant receptors.
Product Specs
Target Background
- Estrogen-induced miR-191 was identified as a direct upstream regulator of DAB2 in ER-positive breast cancer cells. PMID: 29247596
- This research provides comprehensive genomic insights that contribute to a deeper understanding of ER1's biological roles in breast cancer. PMID: 30301189
- This study found a relationship between rs2046210 and rs3803662, and the risk of developing breast cancer in Vietnamese women. The A allele was associated with increased risk for both rs2046210 (OR [95% CI] = 1.43 [1.14 - 1.78], P = 0.0015) and rs3803662 (OR [95% CI] = 1.45 [1.16 - 1.83], P = 0.001). These findings suggest that polymorphisms in ESR1 and TNRC9 are associated with breast cancer risk in the Vietnamese population. PMID: 30078824
- This research demonstrates that Estrogen receptor alpha can enhance odonto/osteogenic differentiation of stem cells from apical papilla via ERK and JNK MAPK pathways. PMID: 30069950
- No association was found between polymorphisms in genes encoding estrogen receptors (ESR1 and ESR2) and excreted BPA levels in orthodontic patients after bracket bonding. PMID: 29961922
- Genome-wide analysis of ER binding sites revealed unique recruitment patterns by mutant ER, leading to allele-specific transcriptional programs. PMID: 29438694
- This study identifies RNF8 as a co-activator of ERalpha that enhances ERalpha stability through a post-transcriptional pathway, providing insights into the mechanisms by which RNF8 promotes cell growth in ERalpha-positive breast cancer. PMID: 28216286
- Reduced expression of ERbeta1 in female ERalpha-negative papillary thyroid carcinoma patients is associated with more advanced disease progression. PMID: 29655286
- ERbeta1 exhibits heterogeneous distribution in deep infiltrating endometriosis. PMID: 29383962
- The ER-alpha36/EGFR signaling loop promotes growth of hepatocellular carcinoma cells. PMID: 29481815
- This study aimed to determine the presence and localization of estrogen receptors (ERs), progesterone receptors (PRs), and androgen receptors (ARs) in both healthy and varicose vein wall cells and their relationship with gender. PMID: 30250632
- Estrogen receptor-alpha expression was observed only in women and showed a positive correlation with the amount of fungi in oral paracoccidioidomycosis, while progesterone receptor was observed in both genders and exhibited no correlation with estrogen receptor-alpha or fungi counting. PMID: 29796757
- ERalpha upregulates vinculin expression in breast cancer cells; Loss of vinculin promotes amoeboid features of cancer cells. PMID: 28266545
- Polymorphisms in the ESR1 and ESR2 genes were not found to predict in vitro fertilization outcome. PMID: 29916276
- High ESR1 expression is associated with metastasis in breast cancer. PMID: 29187405
- The G/G XbaI genotype of the ESR1 gene is associated with breast cancer risk. PMID: 29893332
- miR-221 may impair the protective effect of estrogen in degenerated cartilaginous endplate cells through targeting estrogen receptor alpha. PMID: 29529124
- Results showed that NAT1 and ESR1 expression were increased in primary breast tumor samples compared with normal breast tissue samples, and in ER+ primary breast tumors compared with ER- tumors. Additionally, NAT1 and ESR1 expression appear to have overlapping regulation. PMID: 29901116
- All patients without these mutations detected by molecular barcode next-generation sequencing (MB-NGS) were also found to have no mutations by ddPCR. In conclusion, MB-NGS successfully detected ESR1 mutations in cfDNA with a higher sensitivity of 0.1% than conventional NGS and was considered clinically equivalent to ddPCR. PMID: 28905136
- An association was found between the presence of specific genotypes at three ESR1 polymorphisms (rs2234693, rs6902771, rs7774230) and one ESR2 polymorphism (rs3020449) and the presence of metabolic syndrome in postmenopausal women. PMID: 30049354
- Higher frequency of ESR1 and PIK3CA mutations was observed in plasma compared to serum in 33 MBC patients; therefore, serum samples should not be considered the preferred source of cfDNA. PMID: 29689710
- These findings suggest that miR-125a-3p can function as a novel tumor suppressor in ER(+) breast cancer by targeting CDK3, which may be a potential therapeutic approach for TamR breast cancer therapy. PMID: 28939591
- A significant finding of this study is that 20% of patients with breast cancer bone metastases exhibited a discrepancy in receptor expression between the primary tumor and subsequent metastases, with loss of hormone receptors (ER and/or PR) expression and gain of HER2 overexpression being the most common changes observed. PMID: 28975433
- This study reports a key role of IGF-IR in regulating the aggressiveness of ERalpha-positive breast cancer cells and the regulation of expression levels of several extracellular matrix molecules. PMID: 28079144
- The associations between PvuII (T>C) and XbaI (A>G) polymorphisms of the estrogen receptor alpha (ESR1) gene with type 2 diabetes mellitus (T2DM) or metabolic syndrome (MetS) are reported. PMID: 29883973
- The ERalpha gene appears to play a crucial role in stress urinary incontinence in the premenopausal period. PMID: 29769420
- This study reports the first discovery of naturally occurring ESR1 (Y537C) and ESR1 (Y537S) mutations in MCF7 and SUM44 ESR1-positive cell lines after acquiring resistance to long-term-estrogen-deprivation (LTED) and subsequent resistance to fulvestrant (ICIR). These mutations became enriched over time, impacting ESR1 binding to the genome and altering the ESR1 interactome. PMID: 29192207
- Concomitant high expression of ERalpha36, GRP78, and GRP94 is associated with aggressive papillary thyroid cancer behavior and may serve as a predictor for extrathyroid extension, lymph node metastasis, and distant metastasis. PMID: 29368272
- Estrogen receptor-1 is a key regulator of HIV-1 latency that imparts gender-specific restrictions on the latent reservoir. PMID: 30061382
- Down-regulation of ESR1 gene expression was enhanced with the development of breast cancer. PMID: 29543921
- This study assessed whether fibrosis markers, estrogen receptor (ER)alpha, and the stromal derived factor (SDF)1/CXC chemokine receptor type 4 (CXCR4) axis are abnormally expressed in intrauterine adhesions endometrium. PMID: 29568895
- The frequency of alleles and genotypes of polymorphisms FSHR(-29G/A) and ESRI (XbaI A/G) in women with normal to poor response did not show a significant correlation. PMID: 29526845
- Each estrogen receptor alpha and estrogen receptor beta gene polymorphism may have different effects on postmenopausal osteoporosis risk and bone mineral density in various ethnicities. PMID: 29458346
- The results suggest that the minor allele A of the ESR1 gene is associated with the development of arterial hypertension in men. PMID: 29658078
- This study found that tamoxifen treatment induced a decrease in PRMT2 and an increase in ER-alpha36 as well as ER-alpha36-mediated non-genomic effect in MDA-MB-231 breast cancer cell line. PMID: 29620287
- ESR1 mutations were not found to be associated with clinical resistance to fulvestrant in breast cancer patients. PMID: 27174596
- Overexpression of COPS5, through its isopeptidase activity, leads to ubiquitination and proteasome-mediated degradation of NCoR, a key corepressor for ERalpha and tamoxifen-mediated suppression of ERalpha target genes. PMID: 27375289
- ESR alpha PvuII and XbaI polymorphisms are not associated with systemic lupus erythematosus. The combination of the TC/AA and CC/GG genotypes were associated with SLE susceptibility. PMID: 29356461
- Estrogen receptor (ER) and progesterone receptor (PR) expression in endometrial carcinoma (EC) were significantly higher than those in the paracarcinoma tissue and control. PMID: 29081408
- ESR1 promoter methylation was an independent risk factor and had a high value in predicting 28-day mortality from acute-on-chronic hepatitis B liver failure. PMID: 29082740
- By analyzing different estrogen receptor-alpha(ER-a)-positive and ER-a-negative breast cancer cell lines, we defined the role of CCN5 in the leptin-mediated regulation of growth and invasive capacity. PMID: 29370782
- This study identified ESR1 as a direct target of miR-301a-3p. PMID: 29763890
- This study reports, for the first time, the presence of ESR1 methylation in plasma ctDNA of patients with HGSC. The agreement between ESR1 methylation in primary tumors and paired ctDNA is statistically significant. PMID: 29807696
- This study reports the development of a novel class of ERa AF2 inhibitors, which have the potential to effectively inhibit ERa activity by a unique mechanism and circumvent the issue of mutation-driven resistance in breast cancer. PMID: 29462880
- The P2X7R rs3751143 and ER-alpha PvuII two-locus interaction confers a significantly high susceptibility to osteoporosis in Chinese postmenopausal women. PMID: 28884379
- Alcohol consumption may have differential effects on concordant and discordant receptor subtypes of breast cancer. PMID: 29353824
- ERalpha and ERbeta mRNA expression was significantly higher (p < 0.05) in tumor tissues relative to their paired normal mucosa and correlated inversely with survival outcome. PMID: 29390981
- High ESR1 expression is associated with Papillary Thyroid Carcinoma. PMID: 28124274
- Oral administration of RAD140 substantially inhibited the growth of AR/ER(+) breast cancer patient-derived xenografts (PDX). Activation of AR and suppression of the ER pathway, including the ESR1 gene, were observed with RAD140 treatment. PMID: 28974548
- Polymorphism in the ERalpha gene is associated with an increased risk for advanced Pelvic Organ Prolapse. However, polymorphism in the LAMC1 gene does not seem to be associated with such risk. PMID: 29241914
