Project description:PFA ependymomas are a lethal glial malignancy of the hindbrain found in babies and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
Project description:Posterior fossa type A (PFA) ependymomas are a lethal glial malignancy of the hindbrain found in babies and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
Project description:PFA (posterior fossa group A) ependymomas are a lethal glial malignancy of the hindbrain found in infants and toddlers. Lacking any highly recurrent somatic mutations, PFAs have been proposed as a largely epigenetically driven tumor type. An almost complete lack of model systems has inhibited discovery of novel PFA therapies. Both in vitro and in vivo, the PFA hypoxic microenvironment controls the availability of specific metabolites to diminish histone methylation, and to increase both histone demethylation and acetylation at H3K27. PFA ependymoma initiates from a cell lineage in the first trimester of human development where there is a known hypoxic microenvironment. Unique to PFA cells, transient exposure to ambient oxygen results in irreversible cellular toxicity. PFA tumors exhibit a low basal level of H3K27me3, and paradoxically inhibition of H3K27 methylation shows significant and specific activity against PFA. Targeting metabolism and/or the epigenome presents a unique opportunity for rational therapy for infants with PFA ependymoma.
Project description:Genome sequencing studies have uncovered the most frequent mutations in cancer and novel targets for therapy. While successful in many tumors, this approach has failed in others. Lethal infant ependymomas (Group A) lies at the far end of this spectrum with no recurrent focal genomic alterations, no recurrent somatic mutations, and no clear driver for targeted therapy. Despite a paucity of genetic aberrations, Group A ependymomas demonstrate widespread epigenetic alterations. We therefore sought to interrogate the oncogenic drivers of ependymoma by characterizing the enhancer landscapes of 30 primary tumors. Super enhancer (SE) mapping revealed novel ependymoma oncogenes such as PAX6, SKI, and FGFRL1 and uncovered subgroup specific SE lesions across ependymoma, specifically, in Group A such as PAX3, MEIS1, and IGF2BP1. Finally, we identified SE associated gene dependencies that maintain FGFR1 and WEE1 expression in ependymoma, demonstrating the utility of SE lesions to predict novel targets for cancer therapy.