title: Cobalt chloride-induced apoptosis and extracellular signal-regulated protein kinase activation in human cervical cancer HeLa cells.
abstract: The molecular mechanism of hypoxia-induced apoptosis has not been clearly elucidated. In this study, we investigated the involvement of extracellular signal-regulated protein kinase (ERK 1/2) in hypoxia-induced apoptosis using cobalt chloride in HeLa human cervical cancer cells. The cobalt chloride was used for the induction of hypoxia, and its IC(50) was 471.4 microM. We demonstrated the DNA fragmentation after incubation with concentrations more than 50 microM cobalt chloride for 24 h, and also evidenced the morphological changes of the cells undergoing apoptosis with electron microscopy. Next, we examined the signaling pathway of cobalt chloride-induced apoptosis in HeLa cells. ERK1/2 activation occurred 6 and 9 h after treatment with 600 microM cobalt chloride. Meanwhile, the pretreatment of the MEK 1 inhibitor (PD98059) completely blocked the cobalt chloride-induced ERK 1/2 activation. At the same time, the activated ERK 1/2 translocated into the nucleus and phosphorylated its transcriptional factor, c-Jun. In addition, the pretreatment of PD98059 inhibited the cobalt chloride-induced DNA fragmentation and apoptotic cell death. These results suggest that cobalt chloride is able to induce apoptotic activity in HeLa cells, and its apoptotic mechanism may be associated with signal transduction via ERK 1/2.
authors.affiliation: Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju 220-710, Korea. Kimtu@dragon.yonsei.ac.kr
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Kim
authors.forename: Seung-Ju
authors.initials: SJ
authors.lastname: Yang
authors.forename: Yoon Suk
authors.initials: YS
authors.lastname: Kim
authors.forename: Tae Ue
authors.initials: TU
authors.lastname: Kim
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D003035:Cobalt / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009687:Nuclear Proteins / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D014157:Transcription Factors
chemical_list: D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005419:Flavonoids; C497442:HIF1A protein, human; D051793:Hypoxia-Inducible Factor 1; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D009687:Nuclear Proteins; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D003035:Cobalt; D020928:Mitogen-Activated Protein Kinases; C018021:cobaltous chloride; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one