MCL1 and neoplasm: In contrast, knocking down Mcl-1 by small interfering RNAs (siRNAs) potentiated the apoptosis of KYSE30 cells induced by SNS-032, as evidence by higher protein levels of PARP cleavage and larger percentage of dead cells in Mcl-1-depleted cells than those of tumor cells transfected with Mock siRNA (Fig. 3D).