title: Abrogation of TNF-mediated cytotoxicity by space flight involves protein kinase C.
abstract: Experiments conducted on STS-50 indicated that space flight significantly inhibited tumor necrosis factor (TNF)-mediated killing of LM929 cells compared to ground controls. In ground-based studies, activation of protein kinase C (PKC) with phorbol 12-myristate 13-acetate (PMA) also inhibited TNF-mediated killing of LM929 cells. Therefore, we used PKC inhibitors to determine if the inhibitory effects of spaceflight on TNF-mediated cytotoxicity involved the activation of PKC. In experiments conducted onboard space shuttle mission STS-54, we saw that in the presence of the protein kinase C inhibitors H7 and H8, TNF-mediated cytotoxicity was restored to levels of those observed in the ground controls. Subsequent experiments done during the STS-57 mission tested the dose response of two protein kinase inhibitors, H7 and HA1004. We again saw that killing was restored in a dose-dependent manner, with inhibitor concentrations known to inhibit PKC being most effective. These data suggest that space flight ameliorates the action of TNF by affecting PKC in target cells.
authors.affiliation: Division of Biology, Kansas State University, Manhattan 66506-4901.
authors.forename: K M
authors.initials: KM
authors.lastname: Woods
authors.forename: S K
authors.initials: SK
authors.lastname: Chapes
mesh_terms: D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000502:physiology*; D047428:Protein Kinase Inhibitors; D013026:Space Flight; D013449:Sulfonamides; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D007546:Isoquinolines; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; D014409:Tumor Necrosis Factor-alpha; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C043204:N-(2-guanidinoethyl)-5-isoquinolinesulfonamide; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate