Therapeutic targeting of BAP1/ASXL3 sub-complex in ASCL1-dependent small cell lung cancer
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA789774 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR17256700.fastq.gz | Fastqsanger.gz | |||
| SRR17256701.fastq.gz | Fastqsanger.gz | |||
| SRR17256676.fastq.gz | Fastqsanger.gz | |||
| SRR17256677.fastq.gz | Fastqsanger.gz | |||
| SRR17256678.fastq.gz | Fastqsanger.gz |
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Project description:Small cell lung cancer (SCLC) is an aggressive disease, with patients diagnosed with either early-stage, limited stage, or extensive stage of SCLC tumor progression. Discovering and targeting the functional biomarkers for SCLC will be crucial in understanding the molecular basis underlying SCLC tumorigenesis to better assist in improving clinical treatment. Emerging studies have demonstrated that dysregulations in BAP1 histone H2A deubiquitinase complex are collectively associated with pathogenesis in human SCLC. Here, we investigated the function of the oncogenic BAP1/ASXL3/BRD4 epigenetic axis in SCLC by developing a next-generation BAP1 inhibitor, iBAP-II, and focusing on the epigenetic balance established between BAP1 and non-canonical PRC1 complexes in regulating SCLC-specific transcriptional programming. We further demonstrated that pharmacologic inhibition of BAP1’s catalytic activity dramatically disrupted BAP1/ASXL3/BRD4 epigenetic axis by inducing protein degradation of the ASXL3 scaffold protein, which bridges BRD4 and BAP1 at active enhancers. Furthermore, treatment of iBAP-II dramatically inhibits SCLC cell viability and tumor growth in vivo via repression of neuroendocrine lineage-specific ASCL1/MYCL/E2F signaling in cells.
2022-02-23 | GSE191106 | GEO
Project description:The bromodomain and extra-terminal (BET) protein BRD4 functions as a transcriptional activator and is a therapeutic target for different human cancers. Here, we report a critical link between Polycomb repressive deubiquitinase-BAP1 (PR-DUB) complex and BRD4, which is bridged by the physical interaction between additional sex combs-like protein 3 (ASXL3) in small cell lung cancer (SCLC). We further showed that ASXL3 functions as an adaptor protein, which directly interacts with BRD4-extra-terminal (ET) domain via a novel BRD4 binding motif (BBM), and maintains chromatin occupancy of BRD4 at active enhancers. Genetic depletion of ASXL3 leads to a genome-wide reduction of histone H3K27Ac levels as well as BRD4 occupancy, resulting in a similar change of gene expression profile induced by BET inhibitors. Pharmacologically-induced inhibition with BET specific chemical degrader (dBET6) selectively inhibits cell proliferation of a subtype of SCLC, characterized with high expression of ASXL3. Collectively, this study provides mechanistic insight into the oncogenic function of ASXL3-BRD4 axis in SCLC.
2020-06-24 | GSE145028 | GEO
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| S-EPMC8993689 | biostudies-literature
Project description:The BRCA1-associated protein 1 (BAP1) is a ubiquitin carboxy-terminal hydrolase (UCH), which forms a multi-protein complex with different epigenetic factors such as ASXL1-3, and FOXK1/2. At chromatin, BAP1 catalyzes the removal of mono-ubiquitination on histone H2AK119 in collaboration with other subunits within the complex, and therefore functions as a transcriptional activator. However, the crosstalk between different subunits and how these subunits impact BAP1 function remains unclear. Here, we report the identification of the methyl-CpG-binding domain proteins 5 and 6 (MBD5 and MBD6) that bind to the C-terminal PHD fingers of the large scaffold subunits ASXL1-3 and stabilize the BAP1 complex at chromatin. We further identified a previously uncharacterized Drosophila protein, the six-banded (SBA), as the ortholog of human MBD5/6. We demonstrated the core module of the BAP1 complex is structurally and functionally conserved during the evolution from Drosophila (Calypso/ASX/SBA) to human cells (BAP1/ASXL/MBD). Dysfunction of the BAP1 complex induced by the misregulation/mutations in each subunit is frequent in human cancer. In BAP1-dependent human cancers, MBD6 tends to be a dominant form. Depletion of MBD6 leads to a global loss of BAP1 occupancy at chromatin, resulting in a reduction of BAP1-dependent gene expression and tumor growth in vitro and in vivo. In summary, our study has uncovered MBD5/6 as important regulators of the BAP1 complex and transcription, and sheds light on the therapeutic potential of targeting MBD5/6 in human cancer.
2022-09-15 | GSE196860 | GEO
Project description:Preeclampsia, a life threatening hypertensive disorder of pregnancy, is a leading cause of maternal and perinatal morbidity and mortality. Its early onset form (EO PE), requiring delivery before 34 weeks of gestation, is particularly severe and closely linked to defective trophoblast differentiation. Here, we identify BRCA1-associated protein 1 (BAP1) and its cofactors ASXL2 and ASXL3 are upregulated in EO PE placentas. Enforced BAP1 expression in human trophoblast stem cells reinforced epithelial identity, enhanced adhesion, and impaired both extravillous trophoblast differentiation and syncytiotrophoblast formation. Integrated transcriptomic and proteomic analyses revealed suppression of lineage-specific pathways alongside maintenance of progenitor-like and pro-inflammatory signatures. In trophoblast organoids, excess of BAP1 disrupted syncytial maturation and induced interferon-driven pathways overlapping with EO PE transcriptomes. Together, these findings establish BAP1 as a key regulator of human trophoblast differentiation and implicate its dysregulation in the pathogenesis of EO PE, providing mechanistic insight into the cellular basis of placental dysfunction.
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Project description:In Drosophila, a complex consisting of Calypso and ASX catalyzes H2A deubiquitination and has been reported to act as part of the Polycomb machinery in transcriptional silencing. The mammalian homologs of these proteins (BAP1 and ASXL1/2/3, respectively), are frequently mutated in various cancer types, yet their precise functions remain unclear. Using an integrative approach based on isogenic cell lines generated with CRISPR/Cas9, we uncover an unanticipated role for BAP1 in gene activation. This function requires the assembly of an enzymatically active BAP1-associated core complex (BAP1.com) containing one of the redundant ASXL proteins. We investigate the mechanism underlying BAP1.com-mediated transcriptional regulation and show that it does not participate in Polycomb-mediated silencing. Instead, our results establish that the function of BAP1.com is to safeguard transcriptionally active genes against silencing by the Polycomb Repressive Complex 1.
2019-01-28 | PXD011808 | Pride
Project description:ChIP-Seq analysis performed on 5 ASCL1(+) cell lines and 2 ASCL1 (-) cell lines in order to understand the transcriptome of ASCL1 as it pertains to high-grade neuroendocrine lung cancers 5 ASCL1(+) lung cancer cell lines and 2 ASCL1(-) lung cancer cell lines were compared using ChIP-Seq analysis
2014-10-01 | E-GEOD-61197 | biostudies-arrayexpress
Project description:ASXL1 is the obligate regulatory subunit of a deubiquitinase complex whose catalytic subunit is BAP1. Heterozygous mutations of ASXL1 that result in premature truncations are frequent in myeloid leukemias and Bohring-Opitz syndrome. Here, we demonstrate that truncated ASXL1 proteins confer enhanced activity on the ASXL1-BAP1 complex. Stable expression of truncated, hyperactive ASXL1-BAP1 complexes in a hematopoietic precursor cell line resulted in global erasure of H2AK119Ub, striking depletion of H3K27me3, selective upregulation of a subset of genes whose promoters bore both H2AK119Ub and H3K4me3, and spontaneous differentiation to the mast cell lineage. These outcomes required the catalytic activity of BAP1, indicating these events were downstream consequences of H2AK119Ub erasure. In bone marrow precursors, truncated ASXL1-BAP1 expression cooperated with TET2 loss-of-function to increase differentiation to the myeloid lineage in vivo. We propose that pathological ASXL1 mutations confer gain-of-function on the ASXL-BAP1 complex. ChIP-Seq for H2AK119Ub, H3K4me3, H3K27me3 on EML cells. RNA-Seq on EML cells expressing ASXL1(1-479)+BAP1 and control.
2015-03-11 | E-GEOD-65555 | biostudies-arrayexpress
Project description:Neuroblastoma is a heterogeneous paediatric cancer arising from developmentally arrested neuronal precursors, where restoring differentiation offers therapeutic promise. ASCL1, a pro-neural transcription factor, is widely expressed in neuroblastoma and can drive either proliferation or differentiation depending on the cellular context. Here, we show that distinct MYCN-amplified neuroblastoma cell lines exhibit differing cell cycle and differentiation responses to ASCL1 overexpression. By comparing genome-wide ASCL1 chromatin binding, transcriptional changes, and protein-protein interactions, we found that ASCL1 binds more extensively to neuronal proteins in a cell line that is more susceptible to ASCL1-driven differentiation, but associates with cell cycle regulators in less responsive cells. We show that CDK2-Cyclin A2 bind ASCL1 in less responsive cells, with CDK-mediated phosphorylation of ASCL1 limiting the ability of ASCL1 to drive differentiation. Our study reveals that context-dependent interactions of ASCL1 with protein partners on the chromatin control its ability to re-engage a differentiation program in neuroblastoma.
2026-04-07 | PXD056448 | Pride
Project description:ASXL3 bridges BRD4 to BAP1 complex and governs enhancer activity in small cell lung cancer
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