title: Pro-apoptotic gene knockdown mediated by nanocomplexed siRNA reduces radiation damage in primary salivary gland cultures.
abstract: A critical issue in the management of head and neck tumors is radioprotection of the salivary glands. We have investigated whether siRNA-mediated gene knock down of pro-apoptotic mediators can reduce radiation-induced cellular apoptosis in salivary gland cells in vitro. We used novel, pH-responsive nanoparticles to deliver functionally active siRNAs into cultures of salivary gland cells. The nanoparticle molecules are comprised of cationic micelles that electrostatically interact with the siRNA, protecting it from nuclease attack, and also include pH-responsive endosomolytic constituents that promote release of the siRNA into the target cell cytoplasm. Transfection controls with Cy3-tagged siRNA/nanoparticle complexes showed efficiently internalized siRNAs in more than 70% of the submandibular gland cells. We found that introduction of siRNAs specifically targeting the Pkcδ or Bax genes significantly blocked the induction of these pro-apoptotic proteins that normally occurs after radiation in cultured salivary gland cells. Furthermore, the level of cell death from subsequent radiation, as measured by caspase-3, TUNEL, and mitochondrial disruption assays, was significantly decreased. Thus, we have successfully demonstrated that the siRNA/nanoparticle-mediated knock down of pro-apoptotic genes can prevent radiation-induced damage in submandibular gland primary cell cultures.
authors.affiliation: Center for Oral Biology, Department of Microbiology and Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA. szilvia_arany@urmc.rochester.edu
authors.forename: Szilvia
authors.initials: S
authors.lastname: Arany
authors.forename: Qingfu
authors.initials: Q
authors.lastname: Xu
authors.forename: Eric
authors.initials: E
authors.lastname: Hernady
authors.forename: Danielle S W
authors.initials: DS
authors.lastname: Benoit
authors.forename: Steve
authors.initials: S
authors.lastname: Dewhurst
authors.forename: Catherine E
authors.initials: CE
authors.lastname: Ovitt
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D053148:Caspase 3 / Q000096:biosynthesis; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D020287:In Situ Nick-End Labeling; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000378:metabolism; D058726:Nanoconjugates; D061251:Primary Cell Culture; D051745:Protein Kinase C-delta / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000494:pharmacology*; D011832:Radiation Injuries / Q000517:prevention & control*; D011837:Radiation-Protective Agents / Q000494:pharmacology; D012469:Salivary Glands / Q000166:cytology* / Q000528:radiation effects*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D058726:Nanoconjugates; D034741:RNA, Small Interfering; D011837:Radiation-Protective Agents; D051028:bcl-2-Associated X Protein; D051745:Protein Kinase C-delta; D053148:Caspase 3