Inhibition of ATP-induced rapid MMP-9 release by KN-62. PBMCs (2 × 10⁷/mL) with wild-type P2X₇ receptor were incubated with various amount of KN-62 (up to 2 μM) as indicated at 37°C in NaCl medium containing 1 mM CaCl₂ for 15 minutes, followed by addition of 0.8 mM ATP. Supernatants were collected after 30 minutes. MMP-9 activity was detected by gelatin zymography, and MMP-9 concentrations were measured by ELISA. Results from individuals were shown as mean ± SEM (n = 3; panel B).