title: NF-kappaB pathway is involved in griseofulvin-induced G2/M arrest and apoptosis in HL-60 cells.
abstract: Griseofulvin (GF), an oral antifungal agent, has been shown to exert antitumorigenesis effect through G2/M cell cycle arrest in colon cancer cells. But the underlying mechanisms remained obscure. The purpose of this study is to test the cytotoxic effect of GF on HL-60 and HT-29 cells and elucidate its underlying molecular pathways. Dose-dependent and time-course studies by flow cytometry demonstrated that 30 to 60 microM GF significantly induced G2/M arrest and to a less extend, apoptosis, in HL-60 cells. In contrast, only G2/M arrest was observed in HT-29 cells under similar condition. Pretreatment of 30 microM TPCK, a serine protease inhibitor, completely reversed GF-induced G2/M cell cycle arrest and apoptosis in HL-60 cells but not in HT-29 cells. The GF-induced G2/M arrest in HL-60 cells is reversible. Using EMSA and super-shift analysis, we demonstrated that GF stimulated NF-kappaB binding activity in HL-60 cells, which was completely inhibited by pretreatment of TPCK. Treatment of HL-60 with 30 microM GF activated JNK but not ERK or p38 MAPK and subsequently resulted in phosphorylation of Bcl-2. Pretreatment of TPCK to HL-60 cells blocked the GF-induced Bcl-2 phosphorylation but not JNK activation. Time course study demonstrated that activation of cdc-2 kinase activity by GF correlated with Bcl-2 phosphorylation. Taken together, our results suggest that activation of NF-kappaB pathway with cdc-2 activation and phosphorylation of Bcl-2 might be involved in G2/M cell cycle arrest in HL-60 cells.
authors.affiliation: Department of Surgery, Chi-Mei Foundational Medical Center, Yung-Kang City, Tainan, Taiwan.
authors.forename: Yih-Huei
authors.initials: YH
authors.lastname: Uen
authors.forename: Der-Zen
authors.initials: DZ
authors.lastname: Liu
authors.forename: Meng-Shih
authors.initials: MS
authors.lastname: Weng
authors.forename: Yuan-Soon
authors.initials: YS
authors.lastname: Ho
authors.forename: Shyr-Yi
authors.initials: SY
authors.lastname: Lin
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D016203:CDC2 Protein Kinase / Q000378:metabolism; D004273:DNA, Neoplasm / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D016195:G2 Phase / Q000187:drug effects*; D006118:Griseofulvin / Q000494:pharmacology*; D018922:HL-60 Cells; D019073:HT29 Cells; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013997:Time Factors; D014108:Tosylphenylalanyl Chloromethyl Ketone / Q000494:pharmacology
chemical_list: D000935:Antifungal Agents; D004273:DNA, Neoplasm; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D006118:Griseofulvin; D014108:Tosylphenylalanyl Chloromethyl Ketone; D016203:CDC2 Protein Kinase; D048031:JNK Mitogen-Activated Protein Kinases; D015739:Nocodazole