Project description:Transcriptional profile of murine Bap1 null pancreatic cancer cell lines We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genome stability and its loss confers sensitivity to radio- and platinum-based therapies
Project description:Transcriptional profile of PANC1 cells with CRISPR/Cas9 mediated deletion of BAP1 We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genome stability and its loss confers sensitivity to radio- and platinum-based therapies.
Project description:We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genomic stability and its loss confers sensitivity to radio- and platinum-based therapies.
Project description:We found that BAP1 (BRCA1 Associated Protein-1) shows loss of heterozygosity in over 25% of pancreatic cancer patients and functions as tumor suppressor. Conditional deletion of Bap1 in murine pancreas led to genomic instability, accumulation of DNA damage, and an inflammatory response that evolved to pancreatitis with full penetrance. Concomitant expression of oncogenic KrasG12D led to malignant transformation and development of invasive and metastatic pancreatic cancer. At the molecular level, BAP1 maintains the integrity of the exocrine pancreas by regulating genomic stability and its loss confers sensitivity to radio- and platinum-based therapies.
Project description:We report the genome wide binding sites of BAP1, HCF1 and OGT in bone marrow derived macrophages. De-ubiquitinating enzyme BAP1 is mutated in a hereditary cancer syndrome with increased risk of mesothelioma and uveal melanoma. Somatic BAP1 mutations occur in various malignancies. We show that mouse Bap1 gene deletion is lethal during embryogenesis, but systemic or hematopoietic-restricted deletion in adults recapitulates features of human myelodysplastic syndrome (MDS). Knockin mice expressing BAP1 with a 3xFlag tag revealed that BAP1 interacts with host cell factor–1 (HCF-1), O-linked N-acetylglucosamine transferase (OGT), and the polycomb group proteins ASXL1 and ASXL2 in vivo. OGT and HCF-1 levels were decreased by Bap1 deletion, indicating a critical role for BAP1 in stabilizing these epigenetic regulators. Human ASXL1 is mutated frequently in chronic myelomonocytic leukemia (CMML) so an ASXL/BAP1 complex may suppress CMML. A BAP1 catalytic mutation found in a MDS patient implies that BAP1 loss of function has similar consequences in mice and humans. For BAP1, bone marrow derived macrophages were used differentiated from bone marrow cells of BAP1-3X Flag Tagged KI mice we generated. For OGT and HCF1, bone marrow derived macrophages were used from BAP1 WT mice.
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.