title: Nitrofen induces a redox-dependent apoptosis associated with increased p38 activity in P19 teratocarcinoma cells.
abstract: Nitrofen is a diphenyl ether herbicide that produces a spectrum of fetal abnormalities in rodents. To characterize the molecular mechanisms of nitrofen-mediated birth defects at the cellular level, we explored its effects on undifferentiated P19 teratocarcinoma cells. Nitrofen induces a time-dependent cell death of P19 cells that is associated with increases in TUNEL-positivity and caspase-3 cleavage suggesting that nitrofen induces P19 cell apoptosis. In addition, the increase in TUNEL-positive cells was inhibited with zVAD-fmk, suggesting that nitrofen induces a caspase-dependent apoptosis. Nitrofen treatment was associated with increased p38 MAP kinase activity, though pretreatment of cells with multiple p38 inhibitors did not affect nitrofen-mediated caspase-3 cleavage, suggesting caspase-3 cleavage is p38-independent. Nitrofen induced a dose-dependent increase in reactive oxygen species (ROS), which was accompanied by a decrease in the ratio of reduced/oxidized glutathione, indicating that nitrofen alters the cellular redox state of these cells. Furthermore, pretreatment of cells with N-acetyl cysteine gave a dose- and time-dependent reduction of caspase-3 cleavage, supporting the observations that caspase-3 cleavage is cell-redox-dependent. Therefore, nitrofen induces P19 cell apoptosis that is cell-redox-dependent and is associated with increases in p38 activity and ROS and may play a role in nitrofen-mediated birth defects.
authors.affiliation: Pediatric Surgical Research Laboratories, Pediatric Surgical Services, The Department of Surgery, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, WRN 1122, Boston, MA 02114-2696, USA. dkling@partners.org
authors.forename: D E
authors.initials: DE
authors.lastname: Kling
authors.forename: J T
authors.initials: JT
authors.lastname: Aidlen
authors.forename: J C
authors.initials: JC
authors.lastname: Fisher
authors.forename: T B
authors.initials: TB
authors.lastname: Kinane
authors.forename: P K
authors.initials: PK
authors.lastname: Donahoe
authors.forename: J J
authors.initials: JJ
authors.lastname: Schnitzer
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006540:Herbicides / Q000633:toxicity*; D020287:In Situ Nick-End Labeling; D051379:Mice; D010084:Oxidation-Reduction; D010647:Phenyl Ethers / Q000633:toxicity*; D018243:Teratocarcinoma / Q000188:drug therapy / Q000201:enzymology / Q000473:pathology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D006540:Herbicides; D010647:Phenyl Ethers; D048051:p38 Mitogen-Activated Protein Kinases; C007350:nitrofen