(A) A375SM cells were treated with indicated concentrations of shikonin for 24 h and harvested to measure expression levels of Bcl-2, and activation of Bax and cleaved-PARP were detected by Western blot analysis. (B–D) Bar graph was generated by quantifying blots from three independent experiments using ImageJ and normalizing the intensity of the bands to the DMSO-treated control. Significance was determined by Student’s t test, *P<0.05, compared with the DMSO-treated control.