Figure 2. Depletion of ATR sensitizes to FdUrd but not 5-FU, whereas ATM depletion does not affect sensitivity to either agent.

(A, B) HT29 cells, transfected with control (Luc), ATM (A), or ATR (B) siRNAs, were plated as single cells, exposed to the indicated concentrations of 5-FU or FdUrd for 24 h, washed, cultured for 10 d, and stained with Coomassie Blue. Transfected cells were also sequentially immunoblotted (insets) to detect ATM, ATR, and HSP90 (as a loading control). *, non-specific band.