Hyperactivation of ATM upon DNA-PKcs inhibition modulates p53 dynamics and cell fate in response to DNA damage

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• A functional DNA damage response (DDR) is crucial for maintaining genome integrity against DNA double-strand breaks.
• The kinases ATM, ATR, and DNA-PKcs coordinate DNA repair and signal transduction to p53, influencing cell cycle arrest, apoptosis, or senescence.
• The precise interplay between these kinases in orchestrating the DDR remains incompletely understood.

Purpose of the Study:

• To systematically characterize the contribution of ATM, ATR, and DNA-PKcs in regulating p53 activity during the DNA damage response.
• To elucidate the coordinated action of these kinases in ensuring faithful processing of DNA damage signals.
• To investigate the functional consequences of disrupting the interplay between these kinases.

Main Methods:

• Utilized specific kinase inhibitors to target ATM, ATR, and DNA-PKcs.
• Employed quantitative analysis at the single-cell level to assess kinase contributions.
• Investigated the impact on p53 activity and downstream cellular responses like senescence.

Main Results:

• Identified a novel regulatory interplay between DNA-PKcs and ATM.
• Demonstrated that loss of DNA-PKcs function leads to ATM hyperactivation.
• Observed amplified p53 response and increased sensitivity to DNA damage-induced senescence upon DNA-PKcs inhibition.

Conclusions:

• The findings reveal a critical regulatory mechanism where DNA-PKcs influences ATM activity and the subsequent p53-mediated cellular outcome.
• This interplay is p53-dependent and dictates the efficacy of combined treatment strategies involving irradiation and DNA-PKcs inhibitors.
• Highlights the importance of understanding kinase crosstalk for targeted cancer therapies.