Project description:Uveal melanoma is a highly aggressive cancer with a strong propensity for metastasis, yet little is known about the biological mechanisms underlying this metastatic potential. We recently showed that most metastasizing uveal melanomas, which exhibit a class 2 gene expression profile, contain inactivating mutations in the tumor suppressor BAP1. The aim of this study was to investigate the role of BAP1 in uveal melanoma progression. To that end, uveal melanoma cells were studied following stable shRNA-mediated depletion of BAP1. RNA was isolated from three independent uveal melanoma cell lines each stably depleted using shRNA for either BAP1 or the control gene GFP. Two biological replicates were performed for each cell line.
Project description:Uveal melanoma is a highly aggressive cancer with a strong propensity for metastasis, yet little is known about the biological mechanisms underlying this metastatic potential. We recently showed that most metastasizing uveal melanomas, which exhibit a class 2 gene expression profile, contain inactivating mutations in the tumor suppressor BAP1. The aim of this study was to investigate the role of BAP1 in uveal melanoma progression. To that end, uveal melanoma cells were studied following stable shRNA-mediated depletion of BAP1.
Project description:To investigate if knockdown of BAP1 result in an accumulation of the activation mark H3K27ac at the PROS1 locus. Uveal melanoma is a highly metastatic cancer of the eye which is notoriously resistant to therapy. Elucidating the mechanisms of metastasis in order to devise effective therapies has been a major challenge. The strongest genetic risk factor for metastasis in uveal melanoma is the mutational inactivation of the BAP1 tumor-suppressor gene. However, it remains unknown how BAP1 loss promotes tumor progression. Here, we show that BAP1 loss leads to increased expression of PROS1 in uveal melanocytes and melanoma cells, which in turn leads to phosphorylation and activation of the receptor tyrosine kinase MERTK on adjacent macrophages, driving them into a suppressive M2-polarized state. This mechanism could help explain the suppressive tumor immune microenvironment that is characteristic of BAP1-mutant uveal melanomas, and it suggests that BAP1 loss may lead to metastasis at least in part by facilitating immune escape. These findings provide new insights into the role of BAP1 in uveal melanoma, and they nominate new strategies for increasing the efficacy of immunotherapy in this cancer.
Project description:Inactivating mutations of BAP1 are associated with an increased risk of developing metastasis in uveal melanoma (UM), but the roles of BAP1 in UM progression is unclear. To characterize BAP1’s functions in UM, we performed RNA sequencing on BAP1 wild-type and mutant UM cell lines. Differential analysis revealed that BAP1 loss is associated with an upregulated gene expression profile of multiple cell adhesion molecules (CAMs), including E-cadherin (CDH1), cell adhesion molecule 1 (CADM1), and syndecan-2 (SDC2).
Project description:The strong association between BAP1 mutations and highly aggressive Class 2 uveal melanoma (UM) suggests that epigenetic alterations may play a significant role in tumor progression. Thus, we characterized the impact of BAP1 loss on methylomic repatterning in UM.
Project description:The strong association between BAP1 mutations and highly aggressive Class 2 uveal melanoma (UM) suggests that epigenetic alterations may play a significant role in tumor progression. Thus, we characterized the impact of BAP1 loss on the DNA methylome in UM.
Project description:The strong association between BAP1 mutations and highly aggressive Class 2 uveal melanoma (UM) suggests that epigenetic alterations may play a significant role in tumor progression. Thus, we characterized the impact of BAP1 loss on the DNA methylome in UM.
Project description:BRCA1-associated protein 1 (BAP1) is a tumor suppressor and its loss can result in mesothelioma, uveal and cutaneous melanoma, clear cell renal cell carcinoma and bladder cancer. BAP1 is a deubiquitinating enzyme of the UCH class that has been implicated in various cellular processes like cell growth, cell cycle progression, ferroptosis and ER metabolic stress response. Here, we identify novel BAP1 interacting proteins in the cytoplasm by expressing GFP-tagged BAP1 in an endogenous BAP1 deficient cell line using affinity purification followed by mass spec (AP-MS) analysis. Among these novel interacting proteins are all subunits of the heptameric coat protein complex I (COPI) that is involved in vesicle formation and protein cargo binding and sorting.
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.