title: Altered expression of polycomb group genes in glioblastoma multiforme.
abstract: The Polycomb group (PcG) proteins play a critical role in histone mediated epigenetics which has been implicated in the malignant evolution of glioblastoma multiforme (GBM). By systematically interrogating The Cancer Genome Atlas (TCGA), we discovered widespread aberrant expression of the PcG members in GBM samples compared to normal brain. The most striking differences were upregulation of EZH2, PHF19, CBX8 and PHC2 and downregulation of CBX7, CBX6, EZH1 and RYBP. Interestingly, changes in EZH2, PHF19, CBX7, CBX6 and EZH1 occurred progressively as astrocytoma grade increased. We validated the aberrant expression of CBX6, CBX7, CBX8 and EZH2 in GBM cell lines by Western blotting and qRT-PCR, and further the aberrant expression of CBX6 in GBM tissue samples by immunohistochemical staining. To determine if there was functional significance to the diminished CBX6 levels in GBM, CBX6 was overexpressed in GBM cells resulting in decreased proliferative capacity. In conclusion, aberrant expression of PcG proteins in GBMs may play a role in the development or maintenance of the malignancy.
authors.affiliation: Division of Neurosurgery, Department of Surgery, City of Hope National Medical Center, Duarte, California, United States of America.
authors.forename: Gang
authors.initials: G
authors.lastname: Li
authors.forename: Charles
authors.initials: C
authors.lastname: Warden
authors.forename: Zhaoxia
authors.initials: Z
authors.lastname: Zou
authors.forename: Josh
authors.initials: J
authors.lastname: Neman
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Krueger
authors.forename: Alisha
authors.initials: A
authors.lastname: Jain
authors.forename: Rahul
authors.initials: R
authors.lastname: Jandial
authors.forename: Mike
authors.initials: M
authors.lastname: Chen
mesh_terms: D001271:Atlases as Topic; D001932:Brain Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D049109:Cell Proliferation; D030541:Databases, Genetic; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D015894:Genome, Human; D005909:Glioblastoma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D060787:Neoplasm Grading; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D063146:Polycomb-Group Proteins / Q000235:genetics* / Q000378:metabolism; D046888:Tissue Array Analysis
chemical_list: D009363:Neoplasm Proteins; D063146:Polycomb-Group Proteins