The experimental design. (A) The effect of LPS, Nigericin and Glibenclamide on NLRP3 activation. LPS as the signal 1 is a priming trigger inducing the NLRP3 and pro-IL-1β production. Nigericin is the signal 2 and plays role in polymerization of an active NLRP3 inflammasome complex which recruits pro-Caspase-1 and cleaved it to active form of Caspase-1. The Caspase-1 liberates functional IL-1β and IL-18, regulatory cytokines of inflammation. Glibenclamide is a potassium channel inhibitor and blocks the polymerization of NLRP3 protein complex. (B) The experimental control groups consisted of: 1. A549 and PC3 cells treated with glibenclamide for 24 h as the positive control of NLRP3 inhibition; 2. LPS-only for 3 h as the positive control of NLRP3 priming; 3. LPS+nigericin treatment for 24 h as the positive control of active NLRP3 inflammasome complex. The experimental test groups consisted of A549 and PC3 cells treated with doxycycline-only for 24 h and pretreated with LPS for 3 h. U: Untreated PC3 or A549 cells, G: Glibenclamide, L: LPS, N: Nigericin, D: Doxycycline, PRR: The cytosolic pattern recognition receptor, AC1: Active Caspase-1, PC1: Pro-Caspase-1, ASC: Apoptosis-associated speck-like protein containing a CARD, ROS: reactive oxygen species.