Figure 5

Effect of Src tyrosine kinase inhibitor, herbimycin A (HA) on the taxotere-induced phosphorylation status of Bcl-2 and internucleosomal DNA fragmentation. (A) Western blots of treated cell lysates were done as described in Materials and Methods. The HAG/src3-1 cells were treated with either DMSO (vehicle solvent), 100 nM taxotere, taxotere+10 ng/ml HA, or taxotere+100 ng ml⁻¹ HA, for 24 h. Equivalent amounts of immunoprecipitates of anti-Bcl-2 antibody were separated by 12% SDS–PAGE, transferred on nitrocellulose sheet by electroblotting and then immunoblotted by monoclonal antibody against Bcl-2. The arrows indicate the position of unmodified and modified (phosphorylated) Bcl-2. (B) Representative agarose gel of DNA isolated from HAG/src3-1 cells. Cells were exposed to either DMSO±100 ng ml⁻¹ HA, 100 nM taxotere, or taxotere±HA for 24 h, incubated for an additional 24 h in drug-free medium, and subjected to agarose gel electrophoresis. Lane M, 100-bp DNA ladder.