Project description:Activator protein-2γ is a critical determinant of estrogen receptor interactome formation and gene transcription in breast cancer [expression]
Project description:Activator protein-2γ is a critical determinant of estrogen receptor interactome formation and gene transcription in breast cancer [ChIP-Seq]
Project description:This SuperSeries is composed of the following subset Series: GSE25314: FoxA1 is a critical determinant of Estrogen Receptor function and endocrine response (part I) GSE25315: FoxA1 is a critical determinant of Estrogen Receptor function and endocrine response (part II) Refer to individual Series
Project description:Estrogen receptor α (ERα) is key player in the progression of breast cancer. ERα binds to DNA and mediates long-range chromatin interactions throughout the genome, but the underlying mechanism in this process is unclear. Here, we show that AP-2 motifs are highly enriched in the ERα binding sites (ERBS) identified from the recent ChIA-PET of ERα. More importantly, we demonstrate that AP-2γ (also known as TFAP2C), a member of the AP-2 family which has been implicated in breast cancer oncogenesis, is recruited to chromatin in a ligand-independent manner and co-localized with ERα binding events. Furthermore, pertubation of AP-2γ expression disrupts ERα DNA binding, long-range chromatin interactions, and gene transcription. Using ChIP-seq, we show that AP-2γ and ERα binding occurs in close proximity on a genome-wide scale. The majority of these shared genomic regions are also occupied by the pioneer factor, FoxA1. AP-2γ is required for efficient FoxA1 binding and vice versa. Finally, we show that most ERBS associated with long-range chromatin interactions are co-localized with both AP-2γ and FoxA1. Together, our results suggest AP-2γ is an essential factor in ERα-mediated transcription, primarily working together with FoxA1 to facilitate ERα binding and long-range chromatin interactions.
Project description:Estrogen receptor α (ERα) is key player in the progression of breast cancer. ERα binds to DNA and mediates long-range chromatin interactions throughout the genome, but the underlying mechanism in this process is unclear. Here, we show that AP-2 motifs are highly enriched in the ERα binding sites (ERBS) identified from the recent ChIA-PET of ERα. More importantly, we demonstrate that AP-2γ (also known as TFAP2C), a member of the AP-2 family which has been implicated in breast cancer oncogenesis, is recruited to chromatin in a ligand-independent manner and co-localized with ERα binding events. Furthermore, pertubation of AP-2γ expression disrupts ERα DNA binding, long-range chromatin interactions, and gene transcription. Using ChIP-seq, we show that AP-2γ and ERα binding occurs in close proximity on a genome-wide scale. The majority of these shared genomic regions are also occupied by the pioneer factor, FoxA1. AP-2γ is required for efficient FoxA1 binding and vice versa. Finally, we show that most ERBS associated with long-range chromatin interactions are co-localized with both AP-2γ and FoxA1. Together, our results suggest AP-2γ is an essential factor in ERα-mediated transcription, primarily working together with FoxA1 to facilitate ERα binding and long-range chromatin interactions.
Project description:Using a proteomics approach, we identified the Tripartite Motif Containing 37 (TRIM37) as a novel transcriptional coactivator of AP-2γ. We demonstrate TRIM37 facilitates AP-2γ chromatin binding to regulate the AP-2γ mediated transcriptional program directly. We provide evidence that TRIM37 achieves this by stimulating K63-chain-linked polyubiquitination of AP-2γ, promoting protein localization from the cytoplasm to the nucleus. In clinical analyses, we find TRIM37 is upregulated in multiple breast cancer datasets, supporting our findings that TRIM37-AP-2γ interaction is essential for breast cancer tumor growth. Overall, our work revealed that TRIM37 is an oncogenic coactivator of AP-2γ in breast cancer and provides a novel therapeutic target for treating the disease.
Project description:Using a proteomics approach, we identified the Tripartite Motif Containing 37 (TRIM37) as a novel transcriptional coactivator of AP-2γ. We demonstrate TRIM37 facilitates AP-2γ chromatin binding to regulate the AP-2γ mediated transcriptional program directly. We provide evidence that TRIM37 achieves this by stimulating K63-chain-linked polyubiquitination of AP-2γ, promoting protein localization from the cytoplasm to the nucleus. In clinical analyses, we find TRIM37 is upregulated in multiple breast cancer datasets, supporting our findings that TRIM37-AP-2γ interaction is essential for breast cancer tumor growth. Overall, our work revealed that TRIM37 is an oncogenic coactivator of AP-2γ in breast cancer and provides a novel therapeutic target for treating the disease.
2022-07-25 | GSE182546 | GEO
Project description:FoxA1 is a critical determinant of Estrogen Receptor function and endocrine response
Project description:Estrogen receptor alpha (ERalpha) is a ligand-dependent transcription factor that plays an important role in breast cancer. Estrogen-dependent gene regulation by ERalpha can be mediated by interaction with other DNA-binding proteins, such as activator protein-1 (AP-1). The nature of such interactions in mediating the estrogen response in breast cancer cells remains unclear. Here we show that knockdown of c-Fos, a component of the transcription factor AP-1, attenuates the expression of 37% of all estrogen-regulated genes, suggesting that AP-1 is a fundamental factor for ERalpha-mediated transcription. Additionally, knockdown of c-Fos affected the expression of a number of genes that were not regulated by estrogen. Pathway analysis reveals that silencing of c-Fos downregulates an E2F1-dependent pro-proliferative gene network. Thus, modulation of the E2F1 pathway by c-Fos represents a novel mechanism by which c-Fos enhances breast cancer cell proliferation. Furthermore, we show that c-Fos and ERalpha can cooperate in regulating E2F1 gene expression by binding to regulatory elements in the E2F1 promoter. To start to dissect the molecular details of the cross-talk between AP-1 and estrogen signaling, we identify a novel ERalpha/AP-1 target, PKIB (cAMP-dependent protein kinase inhibitor-beta), which is overexpressed in ERalpha-positive breast cancer tissues. Knockdown of PKIB by siRNA results in drastic growth suppression of breast cancer cells. Collectively, our findings support AP-1 as a critical factor that governs estrogen-dependent gene expression and breast cancer proliferation programs. MCF-7 cells were transfected with a control siRNA or with the pool of siRNAs targeting c-Fos for 72 h and were then treated with vehicle or E2 for 24 h, and global gene expression profiles were assessed. Three or four biological replicates were used for each group.
Project description:Gene expression profiling of invasive breast cancer events from the tamoxifen prevention trial validates low estrogen receptor mRNA level as the main determinant of tamoxifen resistance in estrogen receptor positive breast cancer. In NSABP Breast Cancer Prevention Trial (BCPT), tamoxifen reduced the incidence of estrogen receptor (ER) positive tumors but not estrogen receptor negative breast cancer. More importantly, only 69% of estrogen receptor positive tumors were prevented by tamoxifen. The ER positive tumors arising in tamoxifen arm provides an ideal clinical model for acquired tamoxifen resistance. Based on data from NSABP trial B14 which showed linear prediction of the degree of benefit from adjuvant tamoxifen by the levels of ESR1 mRNA coding for ER-alpha, we hypothesized a priori that level of ESR1 mRNA would be lower in ER positive tumors arising in tamoxifen arm compared to those in placebo arm of BCPT. Keywords: Gene expression profiling analysis