CCN5 siRNA does not induce apoptosis in VSMC. 2 × 106 VSMC treated with siRNA were collected after overnight incubation in 10% FCS, washed in PBS, and then the lysates were assayed for caspase-3 activity. Exposure to staurosporine at 2.5 μM in 10% FCS RPMI overnight was used as a positive control for apoptosis. Caspase-3 inhibitor was also added as a control to show that measured OD is due to caspase-3 activity. Values have blank (OD 650 for reaction mix without substrate) subtracted. S = staurosporine, S+I = staurosporine plus inhibitor.