A cell-permeable, non-toxic aminopyrazolocarbonitrile compound that acts as a potent, selective, reversible and cAMP-independent activator of CFTR-dependent Cl
- channel in airway epithelial cells (EC
50 = 1.6 µM in CFTR-expressing Fisher rat thyroid cells). Also shown to activate ΔF508-CFTR in primary CF-HBE cell cultures (EC
50 = 3.5 µM). Reported to directly bind to the same site as CFTR
inh-172 (
>Cat. No. 219670,
>Cat. No. 219674). Does neither elevate intracellular cAMP levels nor appear to have any requirement for cAMP agonist, such as forskolin (
Cat. No. 344270,
Cat. No. 344282). Shown to additively potentiate the G551D-CFTR Cl
- current activated by forskolin with CFTR potentiator, VX-770. Exerts no effect on either Ca
2+-activated Cl
- channel (TMEM16A) or intracellular Ca
2+ levels.
A non-cytotoxic (30 µM for 48 h in human airway epithelial Calu-3 cultures) aminopyrazolocarbonitrile compound that is shown to activate both wt- and ΔF508-CFTR channel activity in a cAMP-independent, reversible, and CFTR
inh-172- (Cat. Nos.
219670 &
219674) blockable (IC
50 & IC
100 = 0.37 & 30 µM, respectively, against 30 µM C
act using Fisher rat thyroid/FRT cells with wt-CFTR) manner, without affecting CaCC (Calcium-activated chloride channel) function or cellular levels of Ca
2+ and cAMP. The maximum activation inducible by C
act-A1 (EC
max = 13 to 30 µM in Cl
- current induction using in Fisher rat thyroid/FRT and primary human bronchial epithelial/HBE cells) is comparable to that achievable via cAMP stimulation by Forskolin treatment (EC
max = 20 µM; Cat. Nos.
344270 &
34427082), which cannot be further enhanced by Forskolin co-treatment in cells expressing wt-CFTR, although additive effects are seen when C
act-A1 and Forskoklin are applied at suboptimal concentrations to cells with wt-CFTR or when the two drugs are applied at respective EC
max to cells with surface ΔF508-CFTR. Neither C
act-A1 nor Forskolin alone (at 30 µM; and 20 µM;, respectively) can effectively activate FRT with surface G551D-CFTR or primary HNPE (human nasal polyp epithelial) cells with surface G551D/Y1092X-CFTR, while C
act-A1-Forskolin co-treatment results in synergistic activation and maximally achievable activation is reported with a three-drug co-treatment using C
act-A1, Forskolin, and VX-770 (at 30, 20, and 10 µM, respectively).