Why does DNA Damage Response damage DNA?

imagine your house is on fire. you call firemen, they arrive and start throwing molotovs at your burning house.

you might be surprised. but actually it says “firemen” right there in the name.

this is how I think about cellular DNA damage response (DDR)

when DNA is damaged, cell activates p21

p21 then activates ROS, which damage DNA further

wtf is happening here? that just makes a damaged cell even more damaged.

but this feedback loop of self-harm serves a purpose.

senescence co-opts DNA damage to form a positive feedback loop so that cells are never a little damaged.

they’re either pure