title: A whole-genome RNAi screen identifies an 8q22 gene cluster that inhibits death receptor-mediated apoptosis.
abstract: Deregulation of apoptosis is a common occurrence in cancer, for which emerging oncology therapeutic agents designed to engage this pathway are undergoing clinical trials. With the aim of uncovering strategies to activate apoptosis in cancer cells, we used a pooled shRNA screen to interrogate death receptor signaling. This screening approach identified 16 genes that modulate the sensitivity to ligand induced apoptosis, with several genes exhibiting frequent overexpression and/or copy number gain in cancer. Interestingly, two of the top hits, EDD1 and GRHL2, are found 50 kb apart on chromosome 8q22, a region that is frequently amplified in many cancers. By using a series of silencing and overexpression studies, we show that EDD1 and GRHL2 suppress death-receptor expression, and that EDD1 expression is elevated in breast, pancreas, and lung cancer cell lines resistant to death receptor-mediated apoptosis. Supporting the relevance of EDD1 and GRHL2 as therapeutic candidates to engage apoptosis in cancer cells, silencing the expression of either gene sensitizes 8q22-amplified breast cancer cell lines to death receptor induced apoptosis. Our findings highlight a mechanism by which cancer cells may evade apoptosis, and therefore provide insight in the search for new targets and functional biomarkers for this pathway.
authors.affiliation: Department of Molecular Biology, Genentech, South San Francisco, CA 94080, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dompe
authors.forename: Celina Sanchez
authors.initials: CS
authors.lastname: Rivers
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Shaun
authors.initials: S
authors.lastname: Cordes
authors.forename: Martin
authors.initials: M
authors.lastname: Schwickart
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Punnoose
authors.forename: Lukas
authors.initials: L
authors.lastname: Amler
authors.forename: Somasekar
authors.initials: S
authors.lastname: Seshagiri
authors.forename: Jerry
authors.initials: J
authors.lastname: Tang
authors.forename: Zora
authors.initials: Z
authors.lastname: Modrusan
authors.forename: David P
authors.initials: DP
authors.lastname: Davis
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D005820:Genetic Testing; D015894:Genome, Human / Q000235:genetics*; D006801:Humans; D046228:Microarray Analysis; D005810:Multigene Family / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D053218:Receptors, Death Domain / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; C470830:GRHL2 protein, human; D053218:Receptors, Death Domain; D014157:Transcription Factors; C117617:UBR5 protein, human; D044767:Ubiquitin-Protein Ligases