Analysis of chromatin accessibility uncovers TEAD1 as a regulator of migration in human glioblastoma

The intrinsic drivers of migration in glioblastoma (GBM) are poorly understood. To better capture the native molecular imprint of GBM and its developmental context, we isolate human stem cell populations from GBM (GSC) and germinal matrix tissues and map their chromatin accessibility via ATAC-seq. We uncover two distinct regulatory GSC signatures, a developmentally-shared/proliferative and a tumor-specific/migratory one in which TEAD1/4 motifs are uniquely overrepresented. Using ChIP-PCR we validate TEAD1 trans occupancy at accessibility sites within EGFR, AQP4, and CDH4. To further characterize TEAD’s functional role in GBM, we knockout TEAD1 or TEAD4 in patient-derived GBM lines using CRISPR-Cas9. TEAD1 ablation robustly diminishes migration, both in vitro and in vivo, and alters migratory and EMT transcriptome signatures with consistent downregulation of its target AQP4. TEAD1 overexpression restores AQP4 expression, and both TEAD1 and AQP4 overexpression rescue migratory deficits in TEAD1-knockout cells, implicating a direct regulatory role for TEAD1-AQP4 in GBM migration. Open chromatin areas were analyzed by ATAC-seq in stem cells from fetal germinal matrix (GM) and from human glioblastoma (GBM) in biological replicates (n ≥ 3). Changes in transcriptome after ablation of TEAD1 and TEAD4 was analyzed by RNA-seq in TEAD1 and TEAD4 CRISPR-KO different GBM patient-derived cell lines (n = 4), as well as in TEAD1 KO gliomaspheres and compared to their corresponding SHAM lines.