Cell experiment:

Each well of a 96-well plate is washed three times with PBS (200 μL/wash), leaving 50 μL of PBS. Test compounds (including CaCCinh-A01) (0.5 μL) are added to each well at 25 μM final concentration. After 10 min, 96-well plates are transferred to a plate reader for fluorescence assay. Each well is assayed individually for TMEM16A-mediated I- influx by recording fluorescence continuously (400 ms/point) for 2 s (base line), then 50 μL of a 140 mM I- solution containing 200 μM ATP is added. The initial rate of I- influx is computed from fluorescence data by nonlinear regression[1].

CaCCinh-A01 is an inhibitor of both TMEM16A and calcium-activated chloride channel (CaCC) with IC50s of 2.1 and 10 μM, respectively.

30 μM CaCCinh-A01 and 100 μM tannic acid strongly inhibit CaCC current following ATP stimulation[1]. Calcium-dependent chloride current is reduced by 38±14, 66±10, and 91±1% by 0.1, 1, and 10 μM CaCCinh-A01, respectively. ATP-induced short-circuit currents are reduced by 38±7 and 78±3% at 10 and 30 μM CaCCinh-A01, respectively[2].

References:
[1]. TMEM16A inhibitors reveal TMEM16A as a minor component of calcium-activated chloridechannel conductance in airway and intestinal epithelial cells. J Biol Chem. 2011 Jan 21;286(3):2365-74.
[2]. De La Fuente R, et al. Small-molecule screen identifies inhibitors of a human intestinal calcium-activated chloridechannel. Mol Pharmacol. 2008 Mar;73(3):758-68.