CFTR Activator; Cact-A1

Biochem/physiol Actions

Reversible: yes

Primary TargetCFTR

Cell permeable: yes

General description

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 (EC₅₀ = 1.6 µM in CFTR-expressing Fisher rat thyroid cells). Also shown to activate δF508-CFTR in primary CF-HBE cell cultures (EC₅₀ = 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 Ca²⁺-activated Cl^- channel (TMEM16A) or intracellular Ca²⁺ 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 (IC₅₀ & IC₁₀₀ = 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 Ca²⁺ 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).

Legal Information

CALBIOCHEM is a registered trademark of Merck KGaA, Darmstadt, Germany

Other Notes

Namkung, W., et al. 2013. Mol. Pharmacol.84, 384.

Packaging

Packaged under inert gas

10 mg in Glass bottle

Reconstitution

Following reconstitution, aliquot and freeze (-20°C). Stock solutions are stable for up to 6 months at -20°C.

Warning

Toxicity: Standard Handling (A)