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Genome-wide RNAi screens in human brain tumor isolates reveal a novel viability requirement for PHF5A.

TitleGenome-wide RNAi screens in human brain tumor isolates reveal a novel viability requirement for PHF5A.
Publication TypeJournal Article
Year of Publication2013
AuthorsHubert CG, Bradley RK, Ding Y, Toledo CM, Herman J, Skutt-Kakaria K, Girard EJ, Davison J, Berndt J, Corrin P, Hardcastle J, Basom R, Delrow JJ, Webb T, Pollard SM, Lee J, Olson JM, Paddison PJ
JournalGenes Dev
Volume27
Issue9
Pagination1032-45
Date Published2013 May 1
ISSN1549-5477
KeywordsAnimals, Brain Neoplasms, Carrier Proteins, Cell Cycle Checkpoints, Cell Line, Cell Proliferation, Cell Survival, Gene Expression, Gene Expression Regulation, Neoplastic, Genome-Wide Association Study, Glioblastoma, Humans, Mice, Neoplastic Stem Cells, Protein Binding, Proto-Oncogene Proteins c-myc, RNA Interference, RNA Splicing, Transplantation, Heterologous
Abstract

To identify key regulators of human brain tumor maintenance and initiation, we performed multiple genome-wide RNAi screens in patient-derived glioblastoma multiforme (GBM) stem cells (GSCs). These screens identified the plant homeodomain (PHD)-finger domain protein PHF5A as differentially required for GSC expansion, as compared with untransformed neural stem cells (NSCs) and fibroblasts. Given PHF5A's known involvement in facilitating interactions between the U2 snRNP complex and ATP-dependent helicases, we examined cancer-specific roles in RNA splicing. We found that in GSCs, but not untransformed controls, PHF5A facilitates recognition of exons with unusual C-rich 3' splice sites in thousands of essential genes. PHF5A knockdown in GSCs, but not untransformed NSCs, astrocytes, or fibroblasts, inhibited splicing of these genes, leading to cell cycle arrest and loss of viability. Notably, pharmacologic inhibition of U2 snRNP activity phenocopied PHF5A knockdown in GSCs and also in NSCs or fibroblasts overexpressing MYC. Furthermore, PHF5A inhibition compromised GSC tumor formation in vivo and inhibited growth of established GBM patient-derived xenograft tumors. Our results demonstrate a novel viability requirement for PHF5A to maintain proper exon recognition in brain tumor-initiating cells and may provide new inroads for novel anti-GBM therapeutic strategies.

DOI10.1101/gad.212548.112
Alternate JournalGenes Dev.
PubMed ID23651857
PubMed Central IDPMC3656321
Grant List5R01 CA114567 / CA / NCI NIH HHS / United States
CA100735 / CA / NCI NIH HHS / United States
P30 CA015704 / CA / NCI NIH HHS / United States
P30 DK056465 / DK / NIDDK NIH HHS / United States
P30CA15704 / CA / NCI NIH HHS / United States
R01 CA135491 / CA / NCI NIH HHS / United States
R01 CA140474 / CA / NCI NIH HHS / United States
R01 CA155360 / CA / NCI NIH HHS / United States
R01CA155360 / CA / NCI NIH HHS / United States
R21 CA170722 / CA / NCI NIH HHS / United States
R21CA170722-01 / CA / NCI NIH HHS / United States
T32 CA080416 / CA / NCI NIH HHS / United States
T32CA080416 / CA / NCI NIH HHS / United States
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