Figure 5.

SP600125, but not a JNK1/2 siRNA inhibits MTA-induced caspase-3 activation, Bcl-2 phosphorylation and cell death. (a, b) Western blot analyses for the status of the indicated proteins in MCF-7 and MCF-7/Casp3 cells treated for the indicated times with 10 nM eribulin or 30 nM paclitaxel in the absence and presence of SP600125 (20 µM) (a) or after a preceding (24 h) transfection with either a control siRNA (siCon) or a siRNA directed against the two JNK isoforms 1 and 2 (siJNK1/2) (b). Blots shown are representative blots of three to four (a) or three (b) independent experiments. (c, d) Fluorometric determination of caspase-3-like DEVDase activities in MCF-7/Casp3 cells treated as described in (a)and (b), respectively. (e, f) Cytometric determination of specific cell death rates (PI uptake) of MCF-7 (e) and MCF-7/Casp3 cells (f) treated for the indicated times as described in (a)and (b), respectively. Values shown are the mean of three (c-d) or of three to five (e-f) independent experiments ± S.D.