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Project description:The androgen receptor (AR) serves as the primary target for therapeutic intervention in prostate cancer (PCa), and AR-targeted treatments constitute the cornerstone of clinical management for this malignancy. Nevertheless, their effectiveness is often compromised by the emergence of resistance mechanisms. These resistant forms of PCa persist in activating AR signaling, highlighting the urgent need for new therapeutic strategies to combat therapy-resistant PCa. Resistance to AR-targeted therapies can manifest through a multitude of mechanisms, including the overexpression of AR splice variants and altered activities of other transcription factors, such as the glucocorticoid receptor (GR) and FOXA1. A shared characteristic among these transcription factors is their dependence on a common set of coregulators, with EP300/CREBBP being a prominent example. This suggests a compelling rationale for employing coregulatory-targeted therapies in the management of treatment-resistant PCa. Here, we aimed to explore the impact of EP300/CREBBP acetyltransferase inhibition on steroid receptor and FOXA1 signaling in PCa cells, employing genome-wide techniques. Our findings illuminate that EP300/CREBBP inhibition exerts a substantial disruptive effect on the AR-regulated transcriptome and receptor chromatin binding, primarily by downregulating the AR-gene. Similarly, the transcriptome regulated by GR and the chromatin binding of the receptor were also hindered, although this was not associated with decreased GR expression levels. Instead, EP300/CREBBP acetyltransferase inhibition leads to a significant reduction in FOXA1 chromatin binding, consequently constraining GR signaling. In summary, our results emphasize how EP300/CREBBP acetyltransferase inhibition distinctly curtails the signaling activities of oncogenic transcription factors, underscoring the potential effectiveness of coregulatory-targeted therapies in PCa.
2024-03-14 | GSE245968 | GEO
Project description:The androgen receptor (AR) serves as the primary target for therapeutic intervention in prostate cancer (PCa), and AR-targeted treatments constitute the cornerstone of clinical management for this malignancy. Nevertheless, their effectiveness is often compromised by the emergence of resistance mechanisms. These resistant forms of PCa persist in activating AR signaling, highlighting the urgent need for new therapeutic strategies to combat therapy-resistant PCa. Resistance to AR-targeted therapies can manifest through a multitude of mechanisms, including the overexpression of AR splice variants and altered activities of other transcription factors, such as the glucocorticoid receptor (GR) and FOXA1. A shared characteristic among these transcription factors is their dependence on a common set of coregulators, with EP300/CREBBP being a prominent example. This suggests a compelling rationale for employing coregulatory-targeted therapies in the management of treatment-resistant PCa. Here, we aimed to explore the impact of EP300/CREBBP acetyltransferase inhibition on steroid receptor and FOXA1 signaling in PCa cells, employing genome-wide techniques. Our findings illuminate that EP300/CREBBP inhibition exerts a substantial disruptive effect on the AR-regulated transcriptome and receptor chromatin binding, primarily by downregulating the AR-gene. Similarly, the transcriptome regulated by GR and the chromatin binding of the receptor were also hindered, although this was not associated with decreased GR expression levels. Instead, EP300/CREBBP acetyltransferase inhibition leads to a significant reduction in FOXA1 chromatin binding, consequently constraining GR signaling. In summary, our results emphasize how EP300/CREBBP acetyltransferase inhibition distinctly curtails the signaling activities of oncogenic transcription factors, underscoring the potential effectiveness of coregulatory-targeted therapies in PCa.
2024-03-14 | GSE245967 | GEO
Project description:The androgen receptor (AR) serves as the primary target for therapeutic intervention in prostate cancer (PCa), and AR-targeted treatments constitute the cornerstone of clinical management for this malignancy. Nevertheless, their effectiveness is often compromised by the emergence of resistance mechanisms. These resistant forms of PCa persist in activating AR signaling, highlighting the urgent need for new therapeutic strategies to combat therapy-resistant PCa. Resistance to AR-targeted therapies can manifest through a multitude of mechanisms, including the overexpression of AR splice variants and altered activities of other transcription factors, such as the glucocorticoid receptor (GR) and FOXA1. A shared characteristic among these transcription factors is their dependence on a common set of coregulators, with EP300/CREBBP being a prominent example. This suggests a compelling rationale for employing coregulatory-targeted therapies in the management of treatment-resistant PCa. Here, we aimed to explore the impact of EP300/CREBBP acetyltransferase inhibition on steroid receptor and FOXA1 signaling in PCa cells, employing genome-wide techniques. Our findings illuminate that EP300/CREBBP inhibition exerts a substantial disruptive effect on the AR-regulated transcriptome and receptor chromatin binding, primarily by downregulating the AR-gene. Similarly, the transcriptome regulated by GR and the chromatin binding of the receptor were also hindered, although this was not associated with decreased GR expression levels. Instead, EP300/CREBBP acetyltransferase inhibition leads to a significant reduction in FOXA1 chromatin binding, consequently constraining GR signaling. In summary, our results emphasize how EP300/CREBBP acetyltransferase inhibition distinctly curtails the signaling activities of oncogenic transcription factors, underscoring the potential effectiveness of coregulatory-targeted therapies in PCa.
2024-03-14 | GSE245966 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of diffuse large B-cell lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway, and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth, and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP-target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small-molecule inhibitors of CARM1 in DLBCL and other cancers.
| S-EPMC7688486 | biostudies-literature
Project description:Despite radiation forming the curative backbone of over 50% of malignancies, there are no genomically-driven radiosensitizers for clinical use. Herein we perform in vivo shRNA screening to identify targets generally associated with radiation response as well as those exhibiting a genomic dependency. This identifies the histone acetyltransferases CREBBP/EP300 as a target for radiosensitization in combination with radiation in cognate mutant tumors. Further in vitro and in vivo studies confirm this phenomenon to be due to repression of homologous recombination following DNA damage and reproducible using chemical inhibition of histone acetyltransferase (HAT), but not bromodomain function. Selected mutations in CREBBP lead to a hyperacetylated state that increases CBP and BRCA1 acetylation, representing a gain of function targeted by HAT inhibition. Additionally, mutations in CREBBP/EP300 are associated with recurrence following radiation in squamous cell carcinoma cohorts. These findings provide both a mechanism of resistance and the potential for genomically-driven treatment.
| S-EPMC8566594 | biostudies-literature
Project description:This SuperSeries is composed of the SubSeries listed below.
2020-06-18 | GSE152668 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152665 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152667 | GEO
Project description:Somatic mutations affecting CREBBP and EP300 are a hallmark of Diffuse Large B Cell Lymphoma (DLBCL). These mutations are frequently monoallelic, within the histone acetyltransferase (HAT) domain and usually mutually exclusive, suggesting that they might affect a common pathway and their residual WT expression is required for cell survival. Using in vitro and in vivo models, we found that inhibition of CARM1 activity (CARM1i) slows DLBCL growth and that the levels of sensitivity are positively correlated with the CREBBP/EP300 mutation load. Conversely, treatment of DLBCLs that do not have CREBBP/EP300 mutations with CARM1i and a CBP/p300 inhibitor revealed a strong synergistic effect. Our mechanistic data show that CARM1i further reduces the HAT activity of CBP genome wide and downregulates CBP target genes in DLBCL cells, resulting in a synthetic lethality that leverages the mutational status of CREBBP/EP300 as a biomarker for the use of small molecule inhibitors of CARM1 in DLBCL and other cancers.
2020-06-18 | GSE152666 | GEO
Project description:FOXA transcription factors are potent, context-specific mediators of development that hold specialized functions in hormone-dependent tissues. Over the last several years, FOXA1 has emerged as a critical mediator of nuclear steroid receptor signalling, manifest at least in part through regulation of androgen receptor and oestrogen receptor activity. Recent findings point towards a major role for FOXA1 in modulating nuclear steroid receptor activity in breast and prostate cancer, and suggest that FOXA1 may significantly contribute to pro-tumourigenic phenotypes. The present review article will focus on the mechanisms, consequence, and clinical relevance of FOXA1-mediated steroid nuclear receptor signalling in human malignancy.
| S-EPMC3209791 | biostudies-literature