title: 2,4-dinitrophenol induces G1 phase arrest and apoptosis in human pulmonary adenocarcinoma Calu-6 cells.
abstract: 2,4-dinitrophenol (DNP) is an uncoupler of oxidative phosphorylation in the mitochondria. Here, we investigated the effect of DNP on the growth of Calu-6 lung cancer cells in view of cell cycle, apoptosis, ROS production and GSH content. DNP dose-dependently decreased cell viability at 72 h (EC50 of about 200 microM) as measured by a MTT assay. The lower doses of DNP induced a G1 arrest of the cell cycle in Calu-6 cells. Analysis of the cell cycle regulatory proteins demonstrated that DNP decreased the steady-state levels of cyclin proteins and cyclin dependent kinase (CDK), but increased the protein levels of cyclin dependent kinase inhibitor (CDKI) p27. DNP also caused a marked increase in apoptosis, as evidenced by DNA fragmentation (sub-G1 DNA content), DAPI staining, the loss of mitochondrial membrane potential (DeltaPsim), externalization of phosphatidylserine (PS). In addition, DNP-treated cells significantly increased the intracellular H2O2 and O2.- levels. All of caspase inhibitors could markedly rescue Calu-6 cells from DNP-induced cell death and only pan-caspase inhibitor, Z-VAD-FMK, could slightly prevent the loss of mitochondrial membrane potential (DeltaPsim). However, none of the caspase inhibitors reduced the increased H2O2 levels, but the increased O2.- levels was slightly attenuated by pan-caspase inhibitor. In addition, the depletion of GSH content in DNP-treated cells was prevented by all of caspase inhibitors. In conclusion, DNP, which induced ROS and reduced GSH content, inhibited the growth of Calu-6 cells via cell cycle arrest at G1 phase and apoptosis.
authors.affiliation: Department of Physiology, Medical School, Institute for Medical Sciences, Centers for Healthcare Technology Development, Chonbuk National University, Jeonju 561-180, Republic of Korea.
authors.forename: Yong Hwan
authors.initials: YH
authors.lastname: Han
authors.forename: Sang Wook
authors.initials: SW
authors.lastname: Kim
authors.forename: Suhn Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Sung Zoo
authors.initials: SZ
authors.lastname: Kim
authors.forename: Woo Hyun
authors.initials: WH
authors.lastname: Park
mesh_terms: D019297:2,4-Dinitrophenol / Q000494:pharmacology*; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D005456:Fluorescent Dyes; D016193:G1 Phase / Q000187:drug effects*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D007202:Indicators and Reagents; D007211:Indoles; D008564:Membrane Potentials / Q000187:drug effects; D051336:Mitochondrial Membranes / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D014475:Uncoupling Agents / Q000494:pharmacology*
chemical_list: D017304:Annexin A5; D016213:Cyclins; D005456:Fluorescent Dyes; D007202:Indicators and Reagents; D007211:Indoles; D017382:Reactive Oxygen Species; D014475:Uncoupling Agents; C007293:DAPI; D006861:Hydrogen Peroxide; D018844:Cyclin-Dependent Kinases; D005978:Glutathione; D019297:2,4-Dinitrophenol