Distinct proliferative and neuronal programmes of ASCL1 chromatin binding and gene activation are cell cycle stage dependent [RNA]
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE276843 | GEO | 2025/06/05
REPOSITORIES: GEO
Similar Datasets
Project description:ASCL1 is a potent proneural factor with opposing functions during development, promoting both neuronal progenitor pool expansion and terminal differentiation. How one factor can execute, and switch between, such contradictory functions remain to be elucidated. Using neuroblastoma cells as a model system, we show that ASCL1 exhibits cell cycle phase dependent binding patterns, where G1 phase enriched binding is associated with the priming of pro-neuronal enhancer loci, while SG2M phase enriched binding occurs at promoters of transcribed pro-mitotic genes. Prolonged G1 arrest activates ASCL1-bound and primed neuronal enhancers to drive terminal cell differentiation of these neuroblastic progenitor cells. These findings further our understanding of a key developmental factor, with implications for reprogramming and pathologies such as neuroblastoma.
2025-06-05 | GSE276842 | GEO
Project description:ASCL1 is a potent proneural factor with opposing functions during development, promoting both neuronal progenitor pool expansion and terminal differentiation. How one factor can execute, and switch between, such contradictory functions remain to be elucidated. Using neuroblastoma cells as a model system, we show that ASCL1 exhibits cell cycle phase dependent binding patterns, where G1 phase enriched binding is associated with the priming of pro-neuronal enhancer loci, while SG2M phase enriched binding occurs at promoters of transcribed pro-mitotic genes. Prolonged G1 arrest activates ASCL1-bound and primed neuronal enhancers to drive terminal cell differentiation of these neuroblastic progenitor cells. These findings further our understanding of a key developmental factor, with implications for reprogramming and pathologies such as neuroblastoma.
2025-06-05 | GSE276994 | GEO
Project description:ASCL1, a basic helix-loop-helix family transcription factor, is a master regulator of developmental neurogenesis and a crucial component of transcription factor cocktails that can convert heterologous cell types such as fibroblasts into neurons. The ability of ASCL1 to drive neuronal differentiation is controlled by multi-site phosphorylation but how this modification controls the genome-wide transcriptional activity of ASCL1 is unknown. Using human neuroblastoma cells that maintain a rapidly dividing neuroblastic phenotype yet retain the ability to undergo differentiation as a model system, we find that phosphorylation of ASCL1 has limited effect on target gene promoter association, but predominantly regulates its binding to a subset of distal enhancer regions, resulting in extensive differences in target control by activation, as well as direct and indirect gene repression. These genome-wide analyses reveal how post-translational modification of ASCL1 can change its structure and function, driving it to differential regulatory elements to change cell fate, and controlling ASCL1’s activity as a master transcription regulator of neurogenesis. Using functional mutational and pharmacological approaches, we find that preventing CDK-dependent phosphorylation of ASCL1 in neuroblastoma cells results in co-ordinated suppression of the MYC-driven core circuit supporting neuroblast identity and proliferation, while simultaneously activating a gene programme driving neuronal differentiation. Thus, we show targeting the post-translational modification of a key developmental regulator can re-engage a latent genome-wide programme forcing mitotic exit and differentiation in cancer cells.
2021-03-15 | GSE153823 | GEO
Project description:Genomic aberrations of Cyclin D1 (CCND1) and CDK4 in neuroblastoma indicate that dysregulation of the G1 entry checkpoint is an important cell cycle aberration in this pediatric tumor. Here we report that analysis of Affymetrix expression data of primary neuroblastic tumors shows an extensive over-expression of Cyclin D1 and CDK4 which correlates with histological subgroups and prognosis respectively. Immunohistochemical analysis demonstrated an over-expression of Cyclin D1 in neuroblasts and a low Cyclin D1 expression in all cell types in ganglioneuroma. This suggests an involvement of G1 regulating genes in neuronal differentiation processes which we further evaluated using RNA interference against Cyclin D1 and its kinase partner CDK4 in several neuroblastoma cell lines. This resulted in pRb pathway inhibition as shown by an almost complete disappearance of CDK4 specific pRb phosphorylation; reduction of E2F transcriptional activity and a decrease of Cyclin A protein levels. The Cyclin D1 and CDK4 knock-down resulted in a significant reduction in cell proliferation, a G1 specific cell cycle arrest and moreover an extensive neuronal differentiation. Affymetrix microarray profiling of siRNA treated cells revealed a shift in expression profile towards a neuronal phenotype. Several new potential downstream players are identified. We conclude that neuroblastoma functionally depend on over-expression of G1 regulating genes to maintain their undifferentiated phenotype. Experiment Overall Design: The Cell line IMR-32 at time point 0 and transiently transfected with siRNA against GFP, Cyclin D1 and CDK4 at time point 48 hours. All experiments are biological triplicates.
2008-10-25 | E-GEOD-8866 | biostudies-arrayexpress
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.
2024-10-23 | GSE273957 | GEO
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.
2024-10-23 | GSE273956 | GEO
Project description:Genomic aberrations of Cyclin D1 (CCND1) and CDK4 in neuroblastoma indicate that dysregulation of the G1 entry checkpoint is an important cell cycle aberration in this pediatric tumor. Here we report that analysis of Affymetrix expression data of primary neuroblastic tumors shows an extensive over-expression of Cyclin D1 and CDK4 which correlates with histological subgroups and prognosis respectively. Immunohistochemical analysis demonstrated an over-expression of Cyclin D1 in neuroblasts and a low Cyclin D1 expression in all cell types in ganglioneuroma. This suggests an involvement of G1 regulating genes in neuronal differentiation processes which we further evaluated using RNA interference against Cyclin D1 and its kinase partner CDK4 in several neuroblastoma cell lines. This resulted in pRb pathway inhibition as shown by an almost complete disappearance of CDK4 specific pRb phosphorylation; reduction of E2F transcriptional activity and a decrease of Cyclin A protein levels. The Cyclin D1 and CDK4 knock-down resulted in a significant reduction in cell proliferation, a G1 specific cell cycle arrest and moreover an extensive neuronal differentiation. Affymetrix microarray profiling of siRNA treated cells revealed a shift in expression profile towards a neuronal phenotype. Several new potential downstream players are identified. We conclude that neuroblastoma functionally depend on over-expression of G1 regulating genes to maintain their undifferentiated phenotype. Keywords: Neuroblastoma, CCND1, Cyclin D1, CDK4
2008-08-20 | GSE8866 | GEO
Project description:Basic helix-loop-helix (bHLH) pioneer transcription factors Myod1 and Ascl1 are biochemically related but produce fundamentally different outcomes when expressed in fibroblasts: Myod1 produces muscle cells and Ascl1 induces neurons. Here, we sought to investigate the molecular mechanisms explaining the differential activity. Surprisingly, we found a large overlap in the overall binding patterns of Ascl1 and Myod1 in fibroblasts, with both transcription factors accessing both neuronal and myogenic targets. We also observed similar changes in chromatin accessibility and transcriptional activation. Yet, Myod1 predominantly induced a muscle program and Ascl1 a neuronal program. We found that differences in binding affinity at key targets resulted in largely distinct reprogramming outcomes. Accordingly, exchanging Myod1’s C-terminal protein-protein interacting domain and DNA-binding basic domain with those of Ascl1 induces an Ascl1-like binding and converts Myod1 into a pro-neuronal factor. Finally, we found that co-expression of Myod1 with the transcriptional repressor Myt1l inhibits induction of the muscle program and yields functional neuronal cells. Our findings are compatible with the notion that pioneer factor activity is associated with high-affinity protein-DNA and suggest that promiscuous binding of pioneer factors can induce unspecific lineage features which need to be kept in check by co-factor interactions.
2020-02-03 | GSE140381 | GEO
Project description:Basic helix-loop-helix (bHLH) pioneer transcription factors Myod1 and Ascl1 are biochemically related but produce fundamentally different outcomes when expressed in fibroblasts: Myod1 produces muscle cells and Ascl1 induces neurons. Here, we sought to investigate the molecular mechanisms explaining the differential activity. Surprisingly, we found a large overlap in the overall binding patterns of Ascl1 and Myod1 in fibroblasts, with both transcription factors accessing both neuronal and myogenic targets. We also observed similar changes in chromatin accessibility and transcriptional activation. Yet, Myod1 predominantly induced a muscle program and Ascl1 a neuronal program. We found that differences in binding affinity at key targets resulted in largely distinct reprogramming outcomes. Accordingly, exchanging Myod1’s C-terminal protein-protein interacting domain and DNA-binding basic domain with those of Ascl1 induces an Ascl1-like binding and converts Myod1 into a pro-neuronal factor. Finally, we found that co-expression of Myod1 with the transcriptional repressor Myt1l inhibits induction of the muscle program and yields functional neuronal cells. Our findings are compatible with the notion that pioneer factor activity is associated with high-affinity protein-DNA and suggest that promiscuous binding of pioneer factors can induce unspecific lineage features which need to be kept in check by co-factor interactions.
2020-02-03 | GSE126413 | GEO
Project description:Basic helix-loop-helix (bHLH) pioneer transcription factors Myod1 and Ascl1 are biochemically related but produce fundamentally different outcomes when expressed in fibroblasts: Myod1 produces muscle cells and Ascl1 induces neurons. Here, we sought to investigate the molecular mechanisms explaining the differential activity. Surprisingly, we found a large overlap in the overall binding patterns of Ascl1 and Myod1 in fibroblasts, with both transcription factors accessing both neuronal and myogenic targets. We also observed similar changes in chromatin accessibility and transcriptional activation. Yet, Myod1 predominantly induced a muscle program and Ascl1 a neuronal program. We found that differences in binding affinity at key targets resulted in largely distinct reprogramming outcomes. Accordingly, exchanging Myod1’s C-terminal protein-protein interacting domain and DNA-binding basic domain with those of Ascl1 induces an Ascl1-like binding and converts Myod1 into a pro-neuronal factor. Finally, we found that co-expression of Myod1 with the transcriptional repressor Myt1l inhibits induction of the muscle program and yields functional neuronal cells. Our findings are compatible with the notion that pioneer factor activity is associated with high-affinity protein-DNA and suggest that promiscuous binding of pioneer factors can induce unspecific lineage features which need to be kept in check by co-factor interactions.
2020-02-03 | GSE126411 | GEO