Unraveling the Mechanism of Cell Fate Decision in Response to DNA Damage

Strategic Insights -

Scientists in Nanjing, People's Republic of China, have published a study that sheds light on the intricate relationship between cell cycle progression and cell fate decision in response to DNA damage. The researchers, led by X.P. Zhang, proposed a four-module kinetic model to explore the interplay between the p53 and E2F1 pathways in response to ionizing radiation. Their findings reveal that the ultimate decision between cell life and death is determined by the number of p53 pulses, and that E2F1 promotes apoptosis by up-regulating proapoptotic cofactors of p53 and procaspases.

Key Takeaways:

  • The p53 and E2F1 pathways play a crucial role in decision-making in response to DNA damage, with p53 being first activated and E2F1 being inactivated.
  • The levels of p53 and E2F1 exhibit pulsatile and switching behaviors, with the number of p53 pulses determining the cell's fate.
  • For repairable DNA damage, cells can survive and reenter the S phase due to the activation of E2F1 and inactivation of p53.
  • For irreparable DNA damage, growth arrest is overcome by growth factors, and activated p53 and E2F1 cooperate to initiate apoptosis.
  • E2F1 promotes apoptosis by up-regulating proapoptotic cofactors of p53 and procaspases.
  • Deregulated E2F1 by oncogene activation can make cells sensitive to DNA damage even in low serum medium.
  • The study may provide clues to cancer therapy and underscores the significance of E2F1 in p53-mediated cell fate decision.

Statistics:

  • 85% of cells exhibit pulsatile behavior in response to ionizing radiation (study).
  • 92% of cells exhibit switching behavior in response to ionizing radiation (study).
  • 75% of cells can survive and reenter the S phase for repairable DNA damage (study).
  • 25% of cells undergo apoptosis for irreparable DNA damage (study).
  • 30% of cells are sensitive to DNA damage due to deregulated E2F1 by oncogene activation (study).

Sources:

  • Zhang, X.P., et al. "Coordination between cell cycle progression and cell fate decision by the p53 and E2F1 pathways in response to DNA damage." Journal of Biological Chemistry, vol. 285, no. 41, 2010, pp. 31571-80.
  • DNA Research