FIG. 7.

Comparison of microtubule- and DNA-damaging anticancer drugs in MCF-7 cells. (A) The microtubule-damaging drugs paclitaxel (0.01 and 0.1 μM), vincristine (0.1 μM), and vinblastine (0.1 μM) induce Bcl2 hyperphosphorylation at 6 h, whereas the DNA-damaging drugs methotrexate (275 μM) and doxorubicin (0.4 μM) do not (no change in a band mobility shift). Cell lysates were fractionated by SDS-PAGE (12% gel) and immunoblotted with anti-Bcl2 antibody. (B) Lower contents of Bax protein in the immunocomplex isolated from paclitaxel (0.01 and 0.1 μM)-, vincristine (0.1 μM)-, and vinblastine (0.1 μM)-treated cells by immunoprecipitation (IP) with anti-Bcl2 antibody (Ab). Proteins were immunoprecipitated with anti-Bcl2 antibody, resolved by SDS-PAGE (12% gel), and immunoblotted with anti-Bax antibody. (C) DNA-damaging anticancer drugs methotrexate (275 μM) and doxorubicin (0.4 μM) induce p53 (lanes 2 and 3), whereas paclitaxel (0.1 μM), vincristine (0.1 μM), and vinblastine (0.1 μM) do not. Cells were treated with drugs for 16 h, harvested, and lysed, and equal amounts of protein were resolved by SDS-PAGE (12% gel) followed by immunoblotting with anti-p53 antibody.