scholarly journals CBP/p300: Critical Co-Activators for Nuclear Steroid Hormone Receptors and Emerging Therapeutic Targets in Prostate and Breast Cancers

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2872
Author(s):  
Aaron R. Waddell ◽  
Haojie Huang ◽  
Daiqing Liao

The CREB-binding protein (CBP) and p300 are two paralogous lysine acetyltransferases (KATs) that were discovered in the 1980s–1990s. Since their discovery, CBP/p300 have emerged as important regulatory proteins due to their ability to acetylate histone and non-histone proteins to modulate transcription. Work in the last 20 years has firmly established CBP/p300 as critical regulators for nuclear hormone signaling pathways, which drive tumor growth in several cancer types. Indeed, CBP/p300 are critical co-activators for the androgen receptor (AR) and estrogen receptor (ER) signaling in prostate and breast cancer, respectively. The AR and ER are stimulated by sex hormones and function as transcription factors to regulate genes involved in cell cycle progression, metabolism, and other cellular functions that contribute to oncogenesis. Recent structural studies of the AR/p300 and ER/p300 complexes have provided critical insights into the mechanism by which p300 interacts with and activates AR- and ER-mediated transcription. Breast and prostate cancer rank the first and forth respectively in cancer diagnoses worldwide and effective treatments are urgently needed. Recent efforts have identified specific and potent CBP/p300 inhibitors that target the acetyltransferase activity and the acetytllysine-binding bromodomain (BD) of CBP/p300. These compounds inhibit AR signaling and tumor growth in prostate cancer. CBP/p300 inhibitors may also be applicable for treating breast and other hormone-dependent cancers. Here we provide an in-depth account of the critical roles of CBP/p300 in regulating the AR and ER signaling pathways and discuss the potential of CBP/p300 inhibitors for treating prostate and breast cancer.

Oncogenesis ◽  
2020 ◽  
Vol 9 (10) ◽  
Author(s):  
Wei Wang ◽  
Urna Kansakar ◽  
Vesna Markovic ◽  
Bingcheng Wang ◽  
Khalid Sossey-Alaoui

Abstract Both TGF-β and the PI3K-AKT signaling pathways are known activators of various intracellular pathways that regulate critical cellular functions, including cancer cell survival and proliferation. The interplay between these two oncogenic pathways plays a major role in promoting the initiation, growth, and progression of tumors, including breast cancers. The molecular underpinning of the inter-relationship between these pathways is, however, not fully understood, as is the role of WAVE3 phosphorylation in the regulation of tumor growth and progression. WAVE3 has been established as a major driver of the invasion–metastasis cascade in breast cancer and other tumors of epithelial origin. WAVE3 phosphorylation downstream of PI3K was also shown to regulate cell migration. Here we show that, in addition to PI3K, WAVE3 tyrosine phosphorylation can also be achieved downstream of TGF-β and EGF and that WAVE3 tyrosine phosphorylation is required for its oncogenic activity. Our in vitro analyses found loss of WAVE3 phosphorylation to significantly inhibit cell migration, as well as tumorsphere growth and invasion. In mouse models for breast cancer, loss of WAVE3 phosphorylation inhibited tumor growth of two aggressive breast cancer cell lines of triple-negative subtype. More importantly, we found that WAVE3 phosphorylation is also required for the activation of PI3K, TGF-β, and EGF signaling and their respective downstream effectors. Therefore, our study identified a novel function for WAVE3 in the regulation of breast cancer development and progression through the modulation of a positive feedback loop between WAVE3 and PI3K-TGF-β-EGF signaling pathways.


Oncogene ◽  
2008 ◽  
Vol 27 (57) ◽  
pp. 7201-7211 ◽  
Author(s):  
A Rodriguez-Gonzalez ◽  
K Cyrus ◽  
M Salcius ◽  
K Kim ◽  
C M Crews ◽  
...  

2010 ◽  
Vol 21 (9) ◽  
pp. 1620-1628 ◽  
Author(s):  
Senad Medunjanin ◽  
Sönke Weinert ◽  
Alexander Schmeisser ◽  
Doris Mayer ◽  
Ruediger C. Braun-Dullaeus

Estrogens are suggested to play a role in the development and progression of proliferative diseases such as breast cancer. Like other steroid hormone receptors, the estrogen receptor-α (ERα) is a substrate of protein kinases, and phosphorylation has profound effects on its function and activity. Given the importance of DNA-dependent protein kinase (DNA-PK) for DNA repair, cell cycle progression, and survival, we hypothesized that it modulates ERα signaling. Here we show that, upon estrogen stimulation, DNA-PK forms a complex with ERα in a breast cancer cell line (MELN). DNA-PK phosphorylates ERα at Ser-118. Phosphorylation resulted in stabilization of ERα protein as inhibition of DNA-PK resulted in its proteasomal degradation. Activation of DNA-PK by double-strand breaks or its inhibition by siRNA technology demonstrated that estrogen-induced ERα activation and cell cycle progression is, at least, partially dependent on DNA-PK.


1980 ◽  
Vol 28 (8) ◽  
pp. 799-810 ◽  
Author(s):  
L P Pertschuk ◽  
E H Tobin ◽  
P Tanapat ◽  
E Gaetjens ◽  
A C Carter ◽  
...  

Histochemical analyses estrogen (ER) and progesterone (PgR) receptors in breast cancer were statistically correlated with results of dextran-coated charcoal (DDC) and sucrose gradient assays. Correlated for ER was 91% of 363 cases, and for PgR 88% of 255 specimens. Breast cancer ER/PgR positivity by histochemistry correlated with a favorable clinical response to endocrine therapies in 72% of 25 cases, while ER/PgR negativity correlated with a lack of response in 96% of 22 cases with Stage IV disease. Nuclear ER/PgR correlated with a poor response to therapy in 8 of 12 patients. An in vitro technique to detect nuclear translocation of ER revealed two groups of ER positive cases, with 11 of 17 exhibiting translocation and 6 not displaying translocation. In prostatic carcinoma, 72% of 65 men were positive for ER and/or androgen receptor. Comparison of specimens obtained without and with electrocautery revealed a preponderance of nuclear binding in the latter, suggesting heat-induced nuclear translocation of receptor. coumestrol, a naturally fluorescent, entirely unaltered estrogen was also used for histochemical detection of ER. Results correlated with ER by DCC in 87% of 61 breast cancers. Coumestrol was additionally used to visually observe receptor and nuclear translocation of ER in intact whole cells in culture.


2020 ◽  
Vol 65 (1) ◽  
pp. T35-T48
Author(s):  
Amy R Dwyer ◽  
Thu H Truong ◽  
Julie H Ostrander ◽  
Carol A Lange

Steroid hormone receptors (SRs) are classically defined as ligand-activated transcription factors that function as master regulators of gene programs important for a wide range of processes governing adult physiology, development, and cell or tissue homeostasis. A second function of SRs includes the ability to activate cytoplasmic signaling pathways. Estrogen (ER), androgen (AR), and progesterone (PR) receptors bind directly to membrane-associated signaling molecules including mitogenic protein kinases (i.e. c-SRC and AKT), G-proteins, and ion channels to mediate context-dependent actions via rapid activation of downstream signaling pathways. In addition to making direct contact with diverse signaling molecules, SRs are further fully integrated with signaling pathways by virtue of their N-terminal phosphorylation sites that act as regulatory hot-spots capable of sensing the signaling milieu. In particular, ER, AR, PR, and closely related glucocorticoid receptors (GR) share the property of accepting (i.e. sensing) ligand-independent phosphorylation events by proline-directed kinases in the MAPK and CDK families. These signaling inputs act as a ‘second ligand’ that dramatically impacts cell fate. In the face of drugs that reliably target SR ligand-binding domains to block uncontrolled cancer growth, ligand-independent post-translational modifications guide changes in cell fate that confer increased survival, EMT, migration/invasion, stemness properties, and therapy resistance of non-proliferating SR+ cancer cell subpopulations. The focus of this review is on MAPK pathways in the regulation of SR+ cancer cell fate. MAPK-dependent phosphorylation of PR (Ser294) and GR (Ser134) will primarily be discussed in light of the need to target changes in breast cancer cell fate as part of modernized combination therapies.


2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 644-644
Author(s):  
R. Kim ◽  
M. Kaneko ◽  
K. Arihiro ◽  
M. Emi ◽  
K. Tanabe ◽  
...  

644 Background: Hormone receptor (HR)-positive breast cancer cells grow through estrogen receptor (ER)-signaling pathways that mediate both genomic and nongenomic actions, which cross-talk with growth factors associated with resistance to tamoxifen. The aim of this study is to explore the clinical significance of extranuclear expression of ER and PR in the cross-talk between HR and growth factor signaling pathways. Methods: We examined the extranuclear expression of ER and PR in 219 primary breast cancers by immunohistochemical staining. Specimens showing such expression were further examined for the expression of pAkt and aromatase. Due to heterogeneity, staining was scored on the basis of intensity and distribution in the tumors. Results: Extranuclear expression of ER or PR was observed in 21 cases (9.5%), which included 4 cases (19.0%) for ER and 20 cases (95.2%) for PR. Among these patients, HER-2, pAkt, and aromatase-positivity were observed in 14 cases (66.6%), 13 cases (61.9%), and 14 cases (66.6%), respectively. On the basis of nuclear HR expression, 11 of these cases were categorized as ER-positive/PR-negative, while 2 were ER-negative/PR-positive. Of those 13 cases, increased pAkt staining was found in 11 cases (84.6%). In particular, among the 11 ER-positive/PR-negative, elevated pAkt and aromatase were found in 10 (90.9%; p<0.01) and 9 cases (81.8%), respectively. Conclusion: PR is more frequently expressed extranuclearly than ER in primary breast cancer, and extranuclear HRs cross-talk with the Akt/HER-2-signaling pathway and activation of aromatase, providing an explanation for the observation that aromatase inhibitors are more beneficial than tamoxifen for ER-positive/PR-negative patients. No significant financial relationships to disclose.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Samuel J. Rodgers ◽  
Lisa M. Ooms ◽  
Viola M. J. Oorschot ◽  
Ralf B. Schittenhelm ◽  
Elizabeth V. Nguyen ◽  
...  

AbstractINPP4B suppresses PI3K/AKT signaling by converting PI(3,4)P2 to PI(3)P and INPP4B inactivation is common in triple-negative breast cancer. Paradoxically, INPP4B is also a reported oncogene in other cancers. How these opposing INPP4B roles relate to PI3K regulation is unclear. We report PIK3CA-mutant ER+ breast cancers exhibit increased INPP4B mRNA and protein expression and INPP4B increased the proliferation and tumor growth of PIK3CA-mutant ER+ breast cancer cells, despite suppression of AKT signaling. We used integrated proteomics, transcriptomics and imaging to demonstrate INPP4B localized to late endosomes via interaction with Rab7, which increased endosomal PI3Kα-dependent PI(3,4)P2 to PI(3)P conversion, late endosome/lysosome number and cargo trafficking, resulting in enhanced GSK3β lysosomal degradation and activation of Wnt/β-catenin signaling. Mechanistically, Wnt inhibition or depletion of the PI(3)P-effector, Hrs, reduced INPP4B-mediated cell proliferation and tumor growth. Therefore, INPP4B facilitates PI3Kα crosstalk with Wnt signaling in ER+ breast cancer via PI(3,4)P2 to PI(3)P conversion on late endosomes, suggesting these tumors may be targeted with combined PI3K and Wnt/β-catenin therapies.


Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3254
Author(s):  
Jianling Xie ◽  
Eric P. Kusnadi ◽  
Luc Furic ◽  
Luke A. Selth

Breast and prostate cancer are the second and third leading causes of death amongst all cancer types, respectively. Pathogenesis of these malignancies is characterised by dysregulation of sex hormone signalling pathways, mediated by the estrogen receptor-α (ER) in breast cancer and androgen receptor (AR) in prostate cancer. ER and AR are transcription factors whose aberrant function drives oncogenic transcriptional programs to promote cancer growth and progression. While ER/AR are known to stimulate cell growth and survival by modulating gene transcription, emerging findings indicate that their effects in neoplasia are also mediated by dysregulation of protein synthesis (i.e., mRNA translation). This suggests that ER/AR can coordinately perturb both transcriptional and translational programs, resulting in the establishment of proteomes that promote malignancy. In this review, we will discuss relatively understudied aspects of ER and AR activity in regulating protein synthesis as well as the potential of targeting mRNA translation in breast and prostate cancer.


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