Expression of c-jun and c-fos in Apoptotic Cells After DNA Damage

• Published in: Cancer investigation 2000, Vol.18 (8), p.715-721
• Main Authors: Kumari, Sunitha R., Alvarez-Gonzalez, Rafael
• Format: Article
• Language: English
• Subjects: Ageing, cell death; Apoptosis; Biological and medical sciences; Blotting, Western; Cell physiology; DNA Damage - genetics; DNA, Neoplasm - metabolism; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Neoplastic; Genes, fos - genetics; Genes, jun - genetics; HeLa Cells - metabolism; Humans; Methylnitronitrosoguanidine; Microscopy, Fluorescence; Molecular and cellular biology; Proto-Oncogene Proteins c-fos - metabolism; Proto-Oncogene Proteins c-jun - metabolism; Time Factors
• ISSN: 0735-7907; 1532-4192
• DOI: 10.3109/07357900009012203

Abstract Apoptosis was induced in HeLa cells by exposure to 50 µM N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for various time intervals (up to 120 min). Apoptotic death was confirmed by the microscopic observation of cell blebbing, cell granulation, and cell aggregation. Cells also showed loss of phospholipid symmetry as judged by immunofluorescent microscopy with fluorescently labeled phosphatidyl serine-specific annexin V. In addition, staining of cells with ethidium bromide showed the presence of genomic DNA apoptotic bodies. The protein expression levels of c-jun and c-fos increased in DNA-damaged HeLa cells after MNNG treatment in a time-dependent fashion. Although the levels of c-fos increased rapidly during the first 30 min and remained high for 2 hr, the increase in c-jun expression was more gradual and slower (60-120 min) after MNNG treatment. These results are consistent with the conclusion that c-fos is important in the initial stages (commitment phase) of apoptosis and c-jun is involved in the late stages (execution phase) of apoptosis induced with alkylating agents