title: Evaluation of IFN-gamma effects on apoptosis and gene expression in neuroblastoma--preclinical studies.
abstract: Loss of caspase-8 expression and resistance to cytotoxic agents occurs frequently in late stage neuroblastoma (NB). Interferon-gamma (IFN-gamma) induces caspase-8 in NB cells, sensitizing them to death receptor mediated apoptosis. This study characterizes the kinetics of this phenomenon and examines the effects of IFN-gamma on global gene expression to determine whether IFN-gamma responses are achievable at physiologically relevant doses and to define the biological effects of this cytokine. Here we examine the IFN-gamma responses of 16 NB cell lines. A single <5-min exposure to IFN-gamma (0.5 ng/ml) induced caspase-8 expression in all non-expressing cell lines and in 3/6 cell lines which already expressed high caspase-8. This increase in caspase-8 proteins was observed within 16 h and persisted for up to 9 days. Furthermore, IFN-gamma pretreatment of NB cells increased doxorubicin-induced apoptosis nearly 3-fold. Microarray analysis was used to identify additional genes involved in proliferation, signaling and apoptosis whose expression was modulated via IFN-gamma. Altered expression of these genes should further enhance the responsiveness of NB cells to chemotherapeutics. Thus, the use of IFN-gamma to sensitize NB cells to cytotoxic agents represents an attractive therapeutic strategy and warrants further investigation.
authors.affiliation: Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
authors.forename: Tanya M
authors.initials: TM
authors.lastname: Tekautz
authors.forename: Kejin
authors.initials: K
authors.lastname: Zhu
authors.forename: Jose
authors.initials: J
authors.lastname: Grenet
authors.forename: Deepak
authors.initials: D
authors.lastname: Kaushal
authors.forename: Vincent J
authors.initials: VJ
authors.lastname: Kidd
authors.forename: Jill M
authors.initials: JM
authors.lastname: Lahti
mesh_terms: D017209:Apoptosis; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D004317:Doxorubicin / Q000494:pharmacology; D004357:Drug Synergism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008745:Methylation; D009447:Neuroblastoma / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
chemical_list: D012333:RNA, Messenger; D004317:Doxorubicin; D007371:Interferon-gamma; D053181:Caspase 8