Figure 6. Effect of N-type calcium channel blocker ziconotide on SH-SY5Y cell viability. (A) Cell viability assay. The cells were treated by ziconotide or ZC88 (5–50 μM) for 24 h and cell viability was determined by SRB assay. Cells without treatment were used as control, with viability set at 100%. Each data point represented the mean ± SEM of three independent experiments. (B) α1B subunit of N-type calcium channel mRNA expression on cancer cells by RT-PCR. M: DNA marker, 1: SH-SY5Y, 2: HT-29, 3: A549, 4: H157, 5: H1299.