title: Synergistic cytotoxicity of Rana catesbeiana ribonuclease and IFN-gamma on hepatoma cells.
abstract: RC-RNase purified from Rana catesbeiana (bullfrog) oocytes is a pyrimidine-guanine sequence-specific ribonuclease. RC-RNase is derived from the RNase superfamily genes exerting distinct ribonucleolytic activity and possesses cytotoxicity to tumor cells, but rarely to primary cells. In this study, we utilized RC-RNase to function with antiproliferative cytokines. The combination with TNF-alpha or TNF-beta would not aggravate cell death. However, the combination with IFN-gamma could induce synergistic cytotoxicity verified by XTT assays toward three hepatoma cell lines bearing different differentiation stages. The distinct cytotoxicity from RC-RNase or RC-RNase/IFN-gamma on different hepatoma cells was correlated with the differentiation extent but not the proliferation rate of the cells. Despite the synergistic cytotoxicity and severe mitochondrial disruptions in the RC-RNase/IFN-gamma-treated cells, we scarcely detected any significant feature of apoptosis or necrosis by FACS analysis on annexin-V/propidium iodide staining. The mechanisms of cell death triggered by RC-RNase or RC-RNase/IFN-gamma require further investigation.
authors.affiliation: Institute of Biology and Anatomy, National Defense Medical Center, Taipei, Taiwan, Republic of China.
authors.forename: C C
authors.initials: CC
authors.lastname: Hu
authors.forename: Y H
authors.initials: YH
authors.lastname: Lee
authors.forename: C H
authors.initials: CH
authors.lastname: Tang
authors.forename: J T
authors.initials: JT
authors.lastname: Cheng
authors.forename: J J
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D029845:Amphibian Proteins; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000473:pathology* / Q000648:ultrastructure; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004722:Endoribonucleases / Q000494:pharmacology*; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology*; D008854:Microscopy, Electron; D008928:Mitochondria / Q000187:drug effects / Q000648:ultrastructure; D013997:Time Factors; D014407:Tumor Cells, Cultured
chemical_list: D029845:Amphibian Proteins; D000970:Antineoplastic Agents; D007371:Interferon-gamma; D004722:Endoribonucleases; C094067:pyrimidine-guanine sequence-specific ribonuclease, Rana catesbeiana