Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. ChIP_Seq examination of AR, FoxA1 and GATA2 binding sites in LNCaP and DU145 cells
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability. genetic_modification_design
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability.
Project description:AR is tightly regulated by many transcriptional cofactors, including key pioneer factor such as FOXA1 and GATA2. While FOXA1 was recently shown to be able to redistribute AR across the genome, how GATA2 regulates AR cistrome has not been carefully investigated. Here, we report that, unlike FOXA1, GATA2 is unable to reprogram AR, but instead it enhances AR program by inducing AR expression and augmenting AR co-occupancy, thereby acting as a pure AR coactivator, rather than a pioneer factor. On the other hand, AR co-occupancy enhances both GATA2 and FOXA1 binding on the chromatin, forming a positive feedback loop. Importantly, we found that FOXA1 is also capable of reprogramming GATA2 by recruiting GATA2 from GATA motif to FKHD-containing regions, being analogous to its pioneering effect on AR signaling. By contrast, GATA2 simply acts as a co-activator of FOXA1 with a lack of pioneering ability.
Project description:GATA2 and FOXA1 are pioneering factors for Androgen Receptor (AR) in prostate cancer cells. Less is known about their role in benign epithelial prostate cells. We investigated if they had the ability to induce differentiation in an undifferentiated prostatic context. Benign basal-like prostate epithelial cells 957E/hTERT-AR cells (a gift from John T. Isaacs lab, Johns Hopkins, MD, USA) were transduced with LentiORF RFP control lentiviral particles. The 957E/hTERT-AR-RFP cells were then transduced with GATA2 and FOXA1 lentiviral particles, and we called the new cell lines hTERT/AR-GATA2 and hTERT/AR-FOXA1, respectively. hTERT/AR-GATA2 is a stable selected cell line and treated with 1 nM anabolic steroids, R1881, or ethanol (ET-OH) for 48 hrs. 957E/hTERT/AR-FOXA1 is a transient cell line, because FOXA1 protein is quickly lost. Twenty four hours post transduction with FOXA1 lentivral particles, 1 nM androgen R1881 or ethanol (ET-OH) were added at time for medium exchange and further treated for 24 hours. GATA-2 and FOXA1 ability to induce differentiation was assessed.
Project description:In prostate cancer, androgen receptor (AR)-targeting agents are very effective in various stages of the disease. However, therapy resistance inevitably occurs and little is known about how tumor cells adapt to bypass AR suppression. Here, we performed integrative multi-omics analyses on tissues isolated before and after 3 months of AR-targeting enzalutamide monotherapy from high-risk prostate cancer patients enrolled in a neoadjuvant clinical trial. Transcriptomic analyses demonstrated that AR inhibition drove tumors towards a neuroendocrine-like disease state. In addition, epigenomic profiling revealed massive enzalutamide-induced reprogramming of pioneer factor FOXA1 – from inactive chromatin binding sites towards active cis-regulatory elements that dictate pro-survival signals. Notably, treatment-induced FOXA1 sites were enriched for the circadian rhythm core component ARNTL. Post-treatment ARNTL levels associated with poor outcome, and ARNTL suppression decreased cell growth in vitro. Our data highlight a remarkable cistromic plasticity of FOXA1 following AR-targeted therapy, and revealed an acquired dependency on circadian regulator ARNTL, a novel candidate therapeutic target.
Project description:Treatment of prostate cancer relies predominantly on the inhibition of androgen receptor (AR) signaling. Despite the initial effectiveness of the AR-targeted therapies, the cancer often develops resistance to the AR blockade. One mechanism of the resistance is glucocorticoid receptor (GR)-mediated replacement of AR. Nevertheless, the mechanistic ways and means how the GR-mediated antiandrogen resistance occurs has remained elusive. Here, we have discovered several crucial features of GR action in prostate cancer cells through genome-wide techniques. We detected that the replacement of AR by GR in antiandrogen-exposed prostate cancer cells occurs almost exclusively at pre-accessible chromatin sites displaying FOXA1 occupancy. Counterintuitively to the classical pioneer factor model, silencing of FOXA1 potentiated the chromatin binding and transcriptional activity of GR. This was attributed to FOXA1-mediated repression of the NR3C1 (gene encoding GR) expression via the corepressor TLE3. In comparison to FOXA1, inhibition of coregulator activity efficiently restricted GR-mediated gene regulation and cell proliferation. Overall, we identified chromatin pre-accessibility and FOXA1-mediated repression as important regulators of GR action in prostate cancer, pointing out new avenues to oppose steroid receptor-mediated drug resistance.
Project description:Treatment of prostate cancer relies predominantly on the inhibition of androgen receptor (AR) signaling. Despite the initial effectiveness of the AR-targeted therapies, the cancer often develops resistance to the AR blockade. One mechanism of the resistance is glucocorticoid receptor (GR)-mediated replacement of AR. Nevertheless, the mechanistic ways and means how the GR-mediated antiandrogen resistance occurs has remained elusive. Here, we have discovered several crucial features of GR action in prostate cancer cells through genome-wide techniques. We detected that the replacement of AR by GR in antiandrogen-exposed prostate cancer cells occurs almost exclusively at pre-accessible chromatin sites displaying FOXA1 occupancy. Counterintuitively to the classical pioneer factor model, silencing of FOXA1 potentiated the chromatin binding and transcriptional activity of GR. This was attributed to FOXA1-mediated repression of the NR3C1 (gene encoding GR) expression via the corepressor TLE3. In comparison to FOXA1, inhibition of coregulator activity efficiently restricted GR-mediated gene regulation and cell proliferation. Overall, we identified chromatin pre-accessibility and FOXA1-mediated repression as important regulators of GR action in prostate cancer, pointing out new avenues to oppose steroid receptor-mediated drug resistance.