FIG 2.

Depletion of SMRT expression compromises the DNA damage response in MCF-7 cells. (A) Western blot analysis showing the impact of SMRT depletion on doxorubicin (Dox)-induced DNA damage. MCF-7 cells were transfected with control (Con) or SMRT-specific siRNA. After 48 h, cells were treated with 0.1% ethanol (lanes V) or 1 nM estradiol (lanes E) for 4 h and subsequently treated with doxorubicin at the indicated concentrations for 16 h. Whole-cell lysates were resolved in SDS-polyacrylamide gels and immunoblotted for γH2AX and SMRT. (B) Saos-2 cells, which are deficient for p53, were analyzed as described for MCF-7 cells in the legend to panel A, except that cells were not treated with hormone. (C) Western blot analysis of PARP cleavage in SMRT-depleted versus control MCF-7 cells with and without doxorubicin treatment. For all blots, actin was used as a loading control.