title: Rac1 is required for oncolytic NDV replication in human cancer cells and establishes a link between tumorigenesis and sensitivity to oncolytic virus.
abstract: Oncolytic Newcastle disease virus (NDV) replicates selectively in most human tumor cells but not in normal cells. The relationship between tumorigenesis and the selective susceptibility of most tumor cells to oncolytic NDV replication is poorly understood. A multistage skin carcinogenesis model derived from non-tumorigenic HaCaT cells was used to systematically investigate the molecular mechanisms involved in the oncolytic NDV-sensitivity associated with tumorigenic transformation. No significant differences in interferon signaling were observed between the virus-sensitive tumor cells and the virus-resistant non-tumorigenic parental cells. Oncogenic H-Ras, which had been used for tumorigenic transformation, was shown to be necessary for virus replication but was not sufficient to render cells susceptible to NDV replication. By using an siRNA screening approach to search for virus-sensitizing genes in the tumorigenic cells, we could identify the small GTPase Rac1 as an oncogenic protein that is essential for NDV replication and anchorage-independent growth in tumorigenic cells. Furthermore, Rac1 expression was sufficient to render non-tumorigenic cells susceptible to NDV replication and to oncolytic cytotoxicity. This study establishes Rac1 as a link between tumorigenesis and oncolytic virus sensitivity in the HaCaT multistage skin carcinogenesis model.
authors.affiliation: Bayer Schering Pharma AG, Global Drug Discovery, Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Puhlmann
authors.forename: F
authors.initials: F
authors.lastname: Puehler
authors.forename: D
authors.initials: D
authors.lastname: Mumberg
authors.forename: P
authors.initials: P
authors.lastname: Boukamp
authors.forename: R
authors.initials: R
authors.lastname: Beier
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D006801:Humans; D009369:Neoplasms / Q000473:pathology* / Q000821:virology*; D009522:Newcastle disease virus / Q000502:physiology*; D050504:Oncolytic Viruses / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D014779:Virus Replication; D020830:rac1 GTP-Binding Protein / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D020830:rac1 GTP-Binding Protein; D018631:ras Proteins