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Expression of c-jun and c-fos in apoptotic cells after DNA damage

S R Kumari1, R Alvarez-Gonzalez

  • 1Department of Molecular Biology and Immunology, University of North Texas Health Science Center, Fort Worth, USA.

Cancer Investigation
|December 7, 2000
PubMed

Insights

N-methyl-N-nitro-N-nitrosoguanidine (MNNG) induces apoptosis in HeLa cells, characterized by distinct cellular changes and DNA fragmentation. The study reveals c-fos involvement in early apoptosis stages and c-jun in later stages.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Apoptosis is a crucial process for cellular homeostasis and development.
  • Understanding the molecular mechanisms of apoptosis is vital for disease research.
  • Alkylating agents like MNNG are known inducers of DNA damage and apoptosis.

Purpose of the Study:

  • To investigate the temporal expression patterns of c-fos and c-jun during MNNG-induced apoptosis in HeLa cells.
  • To elucidate the roles of c-fos and c-jun in different phases of apoptosis.

Main Methods:

  • HeLa cells were treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for varying durations.
  • Apoptosis was assessed via microscopy (cell blebbing, granulation, aggregation), Annexin V staining for phospholipid symmetry, and ethidium bromide staining for DNA fragmentation.
  • Protein expression levels of c-jun and c-fos were analyzed using methods likely involving Western blotting or similar techniques.

Main Results:

  • MNNG treatment induced characteristic apoptotic morphological changes and DNA fragmentation in HeLa cells.
  • Annexin V staining confirmed loss of phospholipid symmetry, a hallmark of early apoptosis.
  • c-fos protein levels increased rapidly within 30 minutes and remained elevated, suggesting a role in the initial apoptosis stages.
  • c-jun protein levels showed a more gradual increase between 60-120 minutes, indicating involvement in later apoptosis stages.

Conclusions:

  • MNNG effectively induces apoptosis in HeLa cells through DNA damage.
  • c-fos appears to be a key mediator in the commitment phase of apoptosis.
  • c-jun plays a significant role in the execution phase of apoptosis induced by alkylating agents like MNNG.

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