Fig. 5.

Radiation induces epigenetic changes in GBM. (A) The 70% confluent plates of HK-374 cell cultures were irradiated with 0 or 4 Gy, and, 48 h after irradiation, the cells were extracted for proteins and used to perform ChIP-PCR assay to analyze for H3K4me3 active chromatin interactions with specific proteins such as Sox2, Oct4, and Nanog. (B) The same set of proteins was also used to perform ELISA for H4 and H3 histone modifiers. (C and D) ATAC-seq samples were collected after 48 h of 0 or 4 Gy irradiation in HK-374 cells. These samples were then analyzed for acquisition of an open chromatin and a closed chromatin state in 0- versus 4-Gy samples. (E) A motif search on both samples was also performed to identify the differentially opened or closed promoter regions with binding motifs for the developmental transcription factors such as Klf4, Pou3f2, E2F2, RUNX1, and MYC. P values were calculated using unpaired t test. *P < 0.05.