title: Attenuation of catalase activity in the malignant phenotype plays a functional role in an in vitro model for tumor progression.
abstract: We have developed an in vitro model to study the molecular mechanisms of tumor progression. Using repeated treatments with ionizing radiation or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), we caused malignant progression of a papilloma producing mouse keratinocyte cell line, 308 cells. In a previous study we have shown that the malignant variants of 308 cells have elevated reactive oxygen species (ROS) levels, and have established a functional role for the pro-oxidant state in the progressed phenotype (Carcinogenesis 20 (1999) 2063). In this study, we have evaluated the status of intracellular defense mechanisms for ROS scavenging in the progressed phenotype to identify sources that contribute to their pro-oxidant state. Our results demonstrate that a reduction in several anti-oxidant defense mechanisms, including catalase and glutathione S-transferase mu, correlates with the emergence of the malignant phenotype. We provide evidence that attenuation of catalase activity may play a functional role in the malignant progression of mouse keratinocytes.
authors.affiliation: Department of Radiation Oncology, Room 4999, Arizona Cancer Center, P.O. Box 240524, 1515 North Campbell Avenue, Tucson, AZ 85724-0524, USA.
authors.forename: A
authors.initials: A
authors.lastname: Gupta
authors.forename: B
authors.initials: B
authors.lastname: Butts
authors.forename: K A
authors.initials: KA
authors.lastname: Kwei
authors.forename: K
authors.initials: K
authors.lastname: Dvorakova
authors.forename: S P
authors.initials: SP
authors.lastname: Stratton
authors.forename: M M
authors.initials: MM
authors.lastname: Briehl
authors.forename: G T
authors.initials: GT
authors.lastname: Bowden
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D015152:Blotting, Northern; D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism* / Q000502:physiology*; D002460:Cell Line; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D005978:Glutathione / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism; D008769:Methylnitronitrosoguanidine; D051379:Mice; D008819:Mice, Nude; D009154:Mutation; D009362:Neoplasm Metastasis; D010100:Oxygen / Q000378:metabolism; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014407:Tumor Cells, Cultured
chemical_list: D000975:Antioxidants; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D008769:Methylnitronitrosoguanidine; D002374:Catalase; D013482:Superoxide Dismutase; D005978:Glutathione; D010100:Oxygen