EC-8042 disrupts both the primary SP/KLF transcription regulatory network and the secondary network induced by HDACi treatment. [ATAC-seq]

Diffuse intrinsic pontine gliomas (DIPGs), frequently harboring H3K27M mutations, are lethal pediatric brain tumors within no effective treatment. By performing ATAC-seq in human pontine progenitor cells (hPPCs) and H3K27M-mutated DIPG cells, we identified that the DIPG-opened chromatin regions are highly enriched for SP/KLF motifs. We show that SP1 depletion or inhibition of SP/KLF DNA binding with EC-8042, an optimized Mithramycin analog, significantly suppresses the proliferation and invasiveness of H3K27M-DIPG cells. In a screen of epigenetic drugs, we find that histone deacetylase inhibitors (HDACi) synergize with EC-8042 to suppress H3K27M-DIPG cell growth. We then performed ATAC-seq in SU-DIPG-XVII cells after treated with DMSO, EC-8042, vorinostat and combination vorinostat with EC-8042. And discovered that HDACi treatment enhances chromatin accessibility to SP/KLF factors, while EC-8042 disrupts both the primary SP/KLF transcription regulatory network and the secondary network induced by HDACi treatment.