ChIP assays were conducted using reagents commercially obtained from Upstate Biotechnology and performed according to the manufacturer's instructions. Briefly, glioma cells were then fixed with formaldehyde for 15 min. Then cells were lysed in SDS lysis buffer, and the chromatin DNA was extracted and sonicated into 200–1000 bp fragments. Purified DNA was used for PCR amplification. Enrichments at target sites were compared with IgG group.