title: HSV-1 amplicon-mediated post-transcriptional inhibition of Rad51 sensitizes human glioma cells to ionizing radiation.
abstract: Standard treatment for glioblastoma multiforme and other brain tumors consists of surgical resection followed by combined radio-/chemotherapy. However, radiation resistance of tumor cells limits the success of this treatment, and the tumors invariably recur. Therefore, the selective inhibition of molecular mediators of radiation resistance may provide therapeutic benefit to the patient. One of these targets is the Rad51 protein, which is a key component of the homologous recombinational repair of DNA double-strand breaks. Here, we investigated whether post-transcriptional silencing of Rad51 by herpes simplex virus-type 1 (HSV-1) amplicon vector-mediated short interfering RNA expression can enhance the antitumor effect of radiation therapy. We demonstrate that these vectors specifically and efficiently inhibited the radiation-induced recruitment of Rad51 into nuclear foci in human glioma cells. The combination of vector-mediated silencing of Rad51 expression and treatment with ionizing radiation resulted in a pronounced reduction of the survival of human glioma cells in culture. In athymyc mice, a single intratumoral injection of Rad51-specific HSV-1 amplicon vector followed by a single radiation treatment resulted in a significant decrease in tumor size. In control animals, including mice that received an intratumoral injection of Rad51-specific amplicon vector but no radiation treatment, the tumor sizes increased.
authors.affiliation: Institute of Virology, University of Zurich, Zurich, Switzerland.
authors.forename: O
authors.initials: O
authors.lastname: Saydam
authors.forename: N
authors.initials: N
authors.lastname: Saydam
authors.forename: D L
authors.initials: DL
authors.lastname: Glauser
authors.forename: M
authors.initials: M
authors.lastname: Pruschy
authors.forename: V
authors.initials: V
authors.lastname: Dinh-Van
authors.forename: M
authors.initials: M
authors.lastname: Hilbe
authors.forename: A H
authors.initials: AH
authors.lastname: Jacobs
authors.forename: M
authors.initials: M
authors.lastname: Ackermann
authors.forename: C
authors.initials: C
authors.lastname: Fraefel
mesh_terms: D000818:Animals; D017209:Apoptosis; D001932:Brain Neoplasms / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D005260:Female; D015870:Gene Expression; D020868:Gene Silencing; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000235:genetics; D005909:Glioblastoma / Q000628:therapy; D005910:Glioma / Q000473:pathology / Q000532:radiotherapy / Q000628:therapy*; D018259:Herpesvirus 1, Human / Q000235:genetics*; D006801:Humans; D015552:Injections, Intralesional; D051379:Mice; D008819:Mice, Nude; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D051135:Rad51 Recombinase / Q000037:antagonists & inhibitors* / Q000235:genetics; D011836:Radiation Tolerance / Q000502:physiology; D016896:Treatment Outcome
chemical_list: D034741:RNA, Small Interfering; D051135:Rad51 Recombinase