Figure 6.

Calpain activation contributed to the proapoptotic effect of Gal-3 knockdown. Cells were pretreated with 20 μM PD150606 for 30 min and then treated with 50 μM cisplatin for 12 h. (ai) Inhibitory effect of PD150606 on calpain activity. Numbers represent the relative intensity of spectrin 150 kD normalized to β-actin. The values of siGal3-11 and siGal3-19 treated with cisplatin only were set as “1”. (aii) The effect of PD150606 on caspase-3 activation, PARP cleavage, caspase-9 activation, and cytochrome c release. Numbers represent the relative intensities of active caspase-3 and PARP 89 kD normalized to β-actin. The values of siGal3-11 and siGal3-19 treated with cisplatin only were set as “1”. (bi) Downregulation of calpain 2 expression by siRNA transfection. After 24 h of transfection, cells were treated with 50 μM cisplatin for 12 h. (bii) Calpain 2 knockdown attenuated cisplatin-induced caspase-3 activation and PARP cleavage. Cells were treated as the same way as bi. Numbers represent the relative intensities of active caspase-3 and PARP 89 kD normalized to β-tubulin. The values of siGal3-11 and siGal3-19 with sicontrol transfection and cisplatin treatment were set as “1”. Data are representative of three independent experiments