Abstract 64: Identification of novel kinases involved in Estrogen receptor-α (ERα) signalling and the development of endocrine resistance in breast cancer

2012 ◽  
Author(s):  
Georgios Giamas ◽  
Hua Zhang ◽  
Wu Zhang ◽  
Aleksandra Filipovic ◽  
Heinz-Josef Lenz ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α

scholarly journals Nuclear Mechanisms Involved in Endocrine Resistance

2021 ◽  
Vol 11 ◽  
Author(s):  
Jürgen Dittmer
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Endocrine Therapy ◽  
Standard Treatment ◽  
Current Knowledge ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α ◽  
Cyclin Dependent Kinase ◽  
Druggable Targets ◽  
Positive Breast Cancer

Endocrine therapy is a standard treatment offered to patients with ERα (estrogen receptor α)-positive breast cancer. In endocrine therapy, ERα is either directly targeted by anti-estrogens or indirectly by aromatase inhibitors which cause estrogen deficiency. Resistance to these drugs (endocrine resistance) compromises the efficiency of this treatment and requires additional measures. Endocrine resistance is often caused by deregulation of the PI3K/AKT/mTOR pathway and/or cyclin-dependent kinase 4 and 6 activities allowing inhibitors of these factors to be used clinically to counteract endocrine resistance. The nuclear mechanisms involved in endocrine resistance are beginning to emerge. Exploring these mechanisms may reveal additional druggable targets, which could help to further improve patients’ outcome in an endocrine resistance setting. This review intends to summarize our current knowledge on the nuclear mechanisms linked to endocrine resistance.

scholarly journals USP35, regulated by estrogen and AKT, promotes breast tumorigenesis by stabilizing and enhancing transcriptional activity of estrogen receptor α

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Jiawei Cao ◽  
Du Wu ◽  
Guang Wu ◽  
Yaqi Wang ◽  
Tianhao Ren ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Transcriptional Activity ◽  
Nuclear Translocation ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α ◽  
Poor Survival ◽  
Primary Resistance

AbstractAlthough endocrine therapies targeting estrogen receptor α (ERα) are effective in managing ER positive (+) breast cancer, many patients have primary resistance or develop resistance to endocrine therapies. In addition, ER+ breast cancer with PIK3CA activating mutations and 11q13-14 amplification have poor survival with unclear mechanism. We uncovered that higher expression of deubiquitinase USP35, located in 11q14.1, was associated with ER+ breast cancer and poor survival. Estrogen enhanced USP35 protein levels by downregulating USP35-targeting miRNA-140-3p and miRNA-26a-5p. USP35 promoted the growth of ER+ breast cancer in vitro and in vivo, and reduced the sensitivity of ER+ breast cancer cells to endocrine therapies such as tamoxifen and fulvestrant. Mechanistically, USP35 enhanced ERα stability by interacting and deubiquitinating ERα, and transcriptional activity of ERα by interacting with ERα in DNA regions containing estrogen response element. In addition, AKT, a key effector of PI3K, phosphorylated USP35 at Serine613, which promoted USP35 nuclear translocation, ERα transcriptional activity, and the growth of ER+ breast cancer cells. Our data indicate that USP35 and ERα form a positive feedback loop in promoting the growth of ER+ breast cancer. USP35 may be a treatment target for ER+ breast cancer with endocrine resistance or with PIK3CA mutations or hyperactivation of the PI3K pathway.

scholarly journals D538G Mutation in Estrogen Receptor-α: A Novel Mechanism for Acquired Endocrine Resistance in Breast Cancer

2013 ◽  
Vol 73 (23) ◽  
pp. 6856-6864 ◽  
Author(s):  
Keren Merenbakh-Lamin ◽  
Noa Ben-Baruch ◽  
Adva Yeheskel ◽  
Addie Dvir ◽  
Lior Soussan-Gutman ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α

scholarly journals Modulating HSF1 levels impacts expression of the estrogen receptor α and antiestrogen response

2021 ◽  
Vol 4 (5) ◽  
pp. e202000811
Author(s):  
Maruhen AD Silveira ◽  
Christophe Tav ◽  
Félix-Antoine Bérube-Simard ◽  
Tania Cuppens ◽  
Mickaël Leclercq ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α ◽  
Heat Shock Factor 1 ◽  
Antiestrogen Resistance ◽  
Breast Cancers ◽  
Proof Of Concept ◽  
Transcriptional Program ◽  
Cellular Functions

Master transcription factors control the transcriptional program and are essential to maintain cellular functions. Among them, steroid nuclear receptors, such as the estrogen receptor α (ERα), are central to the etiology of hormone-dependent cancers which are accordingly treated with corresponding endocrine therapies. However, resistance invariably arises. Here, we show that high levels of the stress response master regulator, the heat shock factor 1 (HSF1), are associated with antiestrogen resistance in breast cancer cells. Indeed, overexpression of HSF1 leads to ERα degradation, decreased expression of ERα-activated genes, and antiestrogen resistance. Furthermore, we demonstrate that reducing HSF1 levels reinstates expression of the ERα and restores response to antiestrogens. Last, our results establish a proof of concept that inhibition of HSF1, in combination with antiestrogens, is a valid strategy to tackle resistant breast cancers. Taken together, we are proposing a mechanism where high HSF1 levels interfere with the ERα-dependent transcriptional program leading to endocrine resistance in breast cancer.

scholarly journals Identification and Roles of miR-29b-1-3p and miR29a-3p-Regulated and Non-Regulated lncRNAs in Endocrine-Sensitive and Resistant Breast Cancer Cells

Cancers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 3530
Author(s):  
Penn Muluhngwi ◽  
Carolyn M. Klinge
Keyword(s):  
Breast Cancer ◽  
Cancer Survival ◽  
Expression Patterns ◽  
Endocrine Resistance ◽  
Estrogen Receptor Α ◽  
Resistant Cell ◽  
Differentially Expressed ◽  
Primary Tumors ◽  
Non Coding Rnas ◽  
Mcf 7

Despite improvements in the treatment of endocrine-resistant metastatic disease using combination therapies in patients with estrogen receptor α (ERα) primary tumors, the mechanisms underlying endocrine resistance remain to be elucidated. Non-coding RNAs (ncRNAs), including microRNAs (miRNA) and long non-coding RNAs (lncRNA), are targets and regulators of cell signaling pathways and their exosomal transport may contribute to metastasis. Previous studies have shown that a low expression of miR-29a-3p and miR-29b-3p is associated with lower overall breast cancer survival before 150 mos. Transient, modest overexpression of miR-29b1-3p or miR-29a-3p inhibited MCF-7 tamoxifen-sensitive and LCC9 tamoxifen-resistant cell proliferation. Here, we identify miR-29b-1/a-regulated and non-regulated differentially expressed lncRNAs in MCF-7 and LCC9 cells using next-generation RNA seq. More lncRNAs were miR-29b-1/a-regulated in LCC9 cells than in MCF-7 cells, including DANCR, GAS5, DSCAM-AS1, SNHG5, and CRND. We examined the roles of miR-29-regulated and differentially expressed lncRNAs in endocrine-resistant breast cancer, including putative and proven targets and expression patterns in survival analysis using the KM Plotter and TCGA databases. This study provides new insights into lncRNAs in endocrine-resistant breast cancer.

scholarly journals PARP7 and Mono-ADP-Ribosylation Negatively Regulate Estrogen Receptor α Signaling in Human Breast Cancer Cells

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 623
Author(s):  
Marit Rasmussen ◽  
Susanna Tan ◽  
Venkata S. Somisetty ◽  
David Hutin ◽  
Ninni Elise Olafsen ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Protein Modification ◽  
Target Genes ◽  
Estrogen Receptor Α ◽  
Transactivation Domain ◽  
Adp Ribosylation ◽  
Protein Levels ◽  
17Β Estradiol ◽  
Mcf 7

ADP-ribosylation is a post-translational protein modification catalyzed by a family of proteins known as poly-ADP-ribose polymerases. PARP7 (TIPARP; ARTD14) is a mono-ADP-ribosyltransferase involved in several cellular processes, including responses to hypoxia, innate immunity and regulation of nuclear receptors. Since previous studies suggested that PARP7 was regulated by 17β-estradiol, we investigated whether PARP7 regulates estrogen receptor α signaling. We confirmed the 17β-estradiol-dependent increases of PARP7 mRNA and protein levels in MCF-7 cells, and observed recruitment of estrogen receptor α to the promoter of PARP7. Overexpression of PARP7 decreased ligand-dependent estrogen receptor α signaling, while treatment of PARP7 knockout MCF-7 cells with 17β-estradiol resulted in increased expression of and recruitment to estrogen receptor α target genes, in addition to increased proliferation. Co-immunoprecipitation assays revealed that PARP7 mono-ADP-ribosylated estrogen receptor α, and mass spectrometry mapped the modified peptides to the receptor’s ligand-independent transactivation domain. Co-immunoprecipitation with truncated estrogen receptor α variants identified that the hinge region of the receptor is required for PARP7-dependent mono-ADP-ribosylation. These results imply that PARP7-mediated mono-ADP-ribosylation may play an important role in estrogen receptor positive breast cancer.

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