Hierarchical synergy of Pten, p53 and Rb pathways in high-grade astrocytoma induced in adult brain

ABSTRACT: Mutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain. Gene expression of 8 human brain samples including 2 normal brainstem and 6 brainstem low-grade gliomas were profiled using HG-U133 plus 2 arrays. Gene expression of 38 mouse tumor samples, including 24 Pten;p53 double knockout and 14 Pten;p53;Rb1 triple knockout, were profiled using Affymetrix Mouse Genome 430 v2 arrays. Copy number changes of 51 double knockout tumor samples were analysed using Roswell Park Cancer Institute 6.5k BAC arrays. Copy number changes of 21 triple knockout tumor samples were analysed using Agilent mouse genome CGH mocirarray 244A.

ORGANISM(S): Homo sapiens

SUBMITTER: Chow LM 

PROVIDER: S-ECPF-GEOD-22927 | biostudies-other | 2011 Mar

REPOSITORIES: biostudies-other