Fig 2: The KCa3.1 channel blocker senicapoc inhibits invasion of A549 cells through an endothelial cell layer(A) Invasion assay. HMEC-1 endothelial cells are seeded on a “sandwiched” collagen matrix consisting of a thick cushion of collagen I superimposed by a thin reconstituted “basememt membrane” containing collagen IV. After endothelial cells have grown to confluency, they are incubated with TNF-α (10 ng/ml) for 24 hours. The following day, A549 cells are added and transendothelial migration is monitored for 13.5 h using live-cell imaging. (B) Series of images of an A549 cell transmigrating through the endothelial cell layer. White arrows indicate the transmigrating A549 cell. (C–F) Analysis of the transmigration experiments. The time course of the experiments is plotted in (C) and (E), the summary of the experiments in (D) and (F). N = 6 experiments each. (C) and (D) Invasion of A549 cells in the presence of DMSO (control conditions) or 30 μmol/l senicapoc. *denotes p < 0.05. (E) and (F) Invasion of A549 cells transfected with siRNA against KCa3.1 channels.

Fig 3: IK1 channels are functionally expressed in U251 glioma cells.(A) Representative recordings of the whole-cell IK1 currents elicited by depolarization step pulses from −120 mV to +80 mV in 20 mV intervals. Whole cell IK1 currents were activated by clamping pipette [Ca2+] at 750 nM. To prevent concomitant activation of BK currents, 2 µM paxilline was added into bath solution. (B) In the same cell shown in (A), the whole cell IK1 currents were inhibited by the potent IK1 blocker clotrimazole (2 µM). (C) Whole cell currents in response to depolarization ramps from −120 mV to +80 mV in the absence or presence of clotrimazole. (D–F) Results of similar experiments employing the selective IK1 blocker TRAM-34 (1 µM).

Fig 4: The KCa3.1 inhibitor senicapoc is orally available and has excellent brain penetration. (A) Chemical structures of the three indicated KCa3.1 blockers and the synthetic scheme for senicapoc. (B) Total plasma and brain concentrations in mice (n = 3) and rats (n = 2) at 1 h after intraperitoneal administration of 50 mg/kg senicapoc in 1 mL miglyol per body weight. (C) Time course of total senicapoc brain and plasma concentrations in mice after intraperitoneal administration of 50 mg/kg senicapoc (n = 3 per time point). (D) Total senicapoc plasma concentrations after oral gavage of 50 mg/kg in rats (n = 3). Data are presented as mean ± SD.

Fig 5: Impact of SKA-31 on locomotor activity in the open field environment and on spontaneous home cage activity in KCa3.1−/− and KCa3.1+/+ mice.Effects of 10 mg/kg or 30 mg/kg SKA-31 (i.p.), or vehicle on distance travelled (A), mean velocity (B), grooming behavior (C), droppings (D), rearing (E), number of turns (F), resting time (G), center/perimeter time ratios (H), and entries into the different zones (I). In DOX-treated and untreated KCa2.3T/T and KCa3.1−/−/KCa2.3T/T (right part of the graphs), 30 mg/kg, SKA-31 produced similar sedation. Representative SMART video tracking files show lasting immobilization in one mouse of either genotype. Numbers in columns (A) are the numbers of mice per group. Statistical comparisons were made between the different series of experiments (a–e) as indicated in (A) and by different column fillings. *P<0.05; **P<0.01; unpaired Student's T-test. (J) 24-hrs telemetric recording showed that KCa3.1−/− (n = 7) had higher diurnal home cage locomotor activity (counts/min) than KCa3.1+/+ (n = 8). Note that the higher 24-hrs-average activity was due to a higher activity during the dark phase (activity phase of mice). Data are given as means ± SEM. * P<0.05; unpaired Student's T-test. (K) SKA-31 (10 and 30 mg i.p at the end of the light phase) lowered night locomotor activity in KCa3.1+/+ (10 mg, n = 5; 30 mg n = 3) but not KCa3.1−/− (10 mg, n = 5; 30 mg n = 3). * P<0.05, before vs. after SKA-31 injections in KCa3.1+/+; paired Student's T-test.