Project description:FOXA (Forkhead Box Protein A) family proteins function as pioneer transcription factors by loosening the compact chromatin structure and facilitating access for other transcription factors. The role of FOXA1 has been intensively studied in normal prostate epithelial cells and the adenocarcinoma subtype of prostate cancer (PCa) where it acts as a critical pioneer factor for the chromatin binding of androgen receptor (AR). Recent studies have indicated the emergence of FOXA2 as an adaptive response to AR signaling inhibition, particularly in prostate tumors that have undergone lineage reprogramming to a neuroendocrine PCa subtype. However, the molecular basis for this transition from FOXA1 to FOXA2 and its role in regulating the development of PCa lineage plasticity remains unclear. In this study, we show that FOXA2 binds to distinct chromatin regions in multiple AR-null PCa models with different molecular subtypes and that its binding is dependent on an epigenetic factor, LSD1. More importantly, we demonstrate that FOXA2 can function as a major pioneer factor of JUN and govern the chromatin binding of AP-1 complex in PCa exhibiting lineage plasticity. Mechanistically, differential reprogramming of JUN activates lineage-specific super-enhancers that may promote PCa progression by enhancing cell state transitions to multiple lineages. Overall, our study reveals a pivotal function of the LSD1-FOXA2 axis in rewiring AP-1 to induce differential transcriptional reprogramming required for PCa lineage plasticity.
Project description:FOXA (Forkhead Box Protein A) family proteins function as pioneer transcription factors by loosening the compact chromatin structure and facilitating access for other transcription factors. The role of FOXA1 has been intensively studied in normal prostate epithelial cells and the adenocarcinoma subtype of prostate cancer (PCa) where it acts as a critical pioneer factor for the chromatin binding of androgen receptor (AR). Recent studies have indicated the emergence of FOXA2 as an adaptive response to AR signaling inhibition, particularly in prostate tumors that have undergone lineage reprogramming to a neuroendocrine PCa subtype. However, the molecular basis for this transition from FOXA1 to FOXA2 and its role in regulating the development of PCa lineage plasticity remains unclear. In this study, we show that FOXA2 binds to distinct chromatin regions in multiple AR-null PCa models with different molecular subtypes and that its binding is dependent on an epigenetic factor, LSD1. More importantly, we demonstrate that FOXA2 can function as a major pioneer factor of JUN and govern the chromatin binding of AP-1 complex in PCa exhibiting lineage plasticity. Mechanistically, differential reprogramming of JUN activates lineage-specific super-enhancers that may promote PCa progression by enhancing cell state transitions to multiple lineages. Overall, our study reveals a pivotal function of the LSD1-FOXA2 axis in rewiring AP-1 to induce differential transcriptional reprogramming required for PCa lineage plasticity.
Project description:FOXA (Forkhead Box Protein A) family proteins function as pioneer transcription factors by loosening the compact chromatin structure and facilitating access for other transcription factors. The role of FOXA1 has been intensively studied in normal prostate epithelial cells and the adenocarcinoma subtype of prostate cancer (PCa) where it acts as a critical pioneer factor for the chromatin binding of androgen receptor (AR). Recent studies have indicated the emergence of FOXA2 as an adaptive response to AR signaling inhibition, particularly in prostate tumors that have undergone lineage reprogramming to a neuroendocrine PCa subtype. However, the molecular basis for this transition from FOXA1 to FOXA2 and its role in regulating the development of PCa lineage plasticity remains unclear. In this study, we show that FOXA2 binds to distinct chromatin regions in multiple AR-null PCa models with different molecular subtypes and that its binding is dependent on an epigenetic factor, LSD1. More importantly, we demonstrate that FOXA2 can function as a major pioneer factor of JUN and govern the chromatin binding of AP-1 complex in PCa exhibiting lineage plasticity. Mechanistically, differential reprogramming of JUN activates lineage-specific super-enhancers that may promote PCa progression by enhancing cell state transitions to multiple lineages. Overall, our study reveals a pivotal function of the LSD1-FOXA2 axis in rewiring AP-1 to induce differential transcriptional reprogramming required for PCa lineage plasticity.
Project description:For FLAG pull-down, protein extracts of cells stably expressing FLAG-tagged FOXA2 were incubated with FLAG-conjugated beads. To perform mass spectrometry analysis, we used at least 6 x 108 cells to map post-translational modification sites through Thermo EASY-nLC 1200 at the Proteomics Core of University of Massachusetts Boston
Project description:In castration-resistant prostate cancer, lineage plasticity mediates resistance to androgen receptor pathway inhibitors (ARPIs) and progression from adenocarcinoma to neuroendocrine prostate cancer (NEPC), a highly aggressive and poorly understood subtype. ASCL1 has emerged as a central regulator of the NEPC phenotype, driving neuroendocrine differentiation. However, ASCL1’s influence on neuronal lineage switching and maturation, as well as its partners in NEPC, remain largely unknown. Here, we provided insights into ASCL1’s cistrome reprogramming in ARPI-induced NEPC versus terminal NEPC and showed that ASCL1 binding pattern tailors the subsequent expression of transcription factor combinations that underlie discrete terminal NEPC identity. We identified FOXA2 as a major co-factor of ASCL1 in terminal NEPC that it is highly expressed in ASCL1-driven NEPC. FOXA2 and ASCL1 interact and work in concert to orchestrate terminal neuronal differentiation in prostate cancer, and regulate key neuroendocrine-associated genes including PROX1. Our findings provide insights into the molecular conduit underlying the interplay between different lineage determinant transcription factors to support the neuroendocrine identity in prostate cancer.
Project description:In castration-resistant prostate cancer, lineage plasticity mediates resistance to androgen receptor pathway inhibitors (ARPIs) and progression from adenocarcinoma to neuroendocrine prostate cancer (NEPC), a highly aggressive and poorly understood subtype. ASCL1 has emerged as a central regulator of the NEPC phenotype, driving neuroendocrine differentiation. However, ASCL1’s influence on neuronal lineage switching and maturation, as well as its partners in NEPC, remain largely unknown. Here, we provided insights into ASCL1’s cistrome reprogramming in ARPI-induced NEPC versus terminal NEPC and showed that ASCL1 binding pattern tailors the subsequent expression of transcription factor combinations that underlie discrete terminal NEPC identity. We identified FOXA2 as a major co-factor of ASCL1 in terminal NEPC that it is highly expressed in ASCL1-driven NEPC. FOXA2 and ASCL1 interact and work in concert to orchestrate terminal neuronal differentiation in prostate cancer, and regulate key neuroendocrine-associated genes including PROX1. Our findings provide insights into the molecular conduit underlying the interplay between different lineage determinant transcription factors to support the neuroendocrine identity in prostate cancer.