title: Induction of in vivo synthetic lethal RNAi responses to treat glioblastoma.
abstract: Glioblastoma multiforme remains one of the most intractable human malignancies. Glioblastomas arise due to activation of multiple oncogenic pathways leading to increased cellular growth, proliferation and tumor cell survival. siRNA induced RNA Interference (RNAi) responses result in the degradation of specific mRNA species. In theory, RNAi responses can selectively target intersecting oncogenic pathways to induce a tumor cell specific RNAi synthetic lethal response. However, the concept of inducing in vivo synthetic lethal RNAi responses has not yet been addressed. Here we tested the in vivo ability of synthetic lethal RNAi responses to treat glioblastoma. To deliver siRNAs into cells, we fused a peptide transduction delivery domain to a dsRNA-binding domain (PTD-DRBD). DRBDs avidly bind to siRNAs, masking the siRNA anionic negative charge and allowing for efficient PTD-mediated siRNA delivery into the entire cell population. Combinatorial targeting of EGF-Receptor (EGFR) and Akt2, but not Ak1 or Akt3, by PTD-DRBD delivered siRNAs synergized to induce tumor cell specific apoptosis. In vivo PTD-DRBD delivery of EGFR and Akt2 siRNAs induced tumor specific apoptosis and significantly increased survival in intracerebral glioblastoma mouse models (p < 0.0005), whereas delivery of irrelevant control siRNAs did not alter longevity. Thus, siRNA induced synthetic lethal RNAi responses have great potential for personalized medicine treatment of cancer.
authors.affiliation: Howard Hughes Medical Institute and Department of Cellular & Molecular Medicine, UCSD School of Medicine, University of California-San Diego, La Jolla, CA, USA.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Michiue
authors.forename: Akiko
authors.initials: A
authors.lastname: Eguchi
authors.forename: Miriam
authors.initials: M
authors.lastname: Scadeng
authors.forename: Steven F
authors.initials: SF
authors.lastname: Dowdy
mesh_terms: D000818:Animals; D017209:Apoptosis; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics; D005804:Genes, Lethal / Q000235:genetics*; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D008136:Longevity; D051379:Mice; D008819:Mice, Nude; D017434:Protein Structure, Tertiary / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000235:genetics; D012330:RNA, Double-Stranded / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000494:pharmacology; D015996:Survival Rate; D014407:Tumor Cells, Cultured; D023041:Xenograft Model Antitumor Assays
chemical_list: D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D066246:ErbB Receptors; C514862:Akt1 protein, mouse; C494922:Akt2 protein, mouse; C491753:Akt3 protein, mouse; D051057:Proto-Oncogene Proteins c-akt