Benzethonium Chloride

Benzethonium chloride inhibits the α7 nAChRs in a mixed competitive and non-competitive manner but there is no voltage- or use-dependence of the response in either subtype. ^[1] Benzethonium chloride inhibits muscarinic signaling with a calculated IC50 of 15 μM and a Hill coefficient of 0.6. ^[3] Benzethonium (5 μM) significantly increases cytosolic Ca(2+)-concentration, decreases forward scatter and triggered annexin V-binding affecting some 30% of the erythrocytes. Benzethonium (5 μM) further significantly enhances the effect of glucose depletion on cytosolic Ca(2+)-concentration and annexin V-binding, but significantly blunts the effect of glucose depletion on forward scatter. Benzethonium (5 μM) significantly enhances lactic acid formation but not ceramide abundance. ^[4] Benzethonium chloride reduces cell viability with IC50 of 3.8 μM in FaDu, 42.2 μM in NIH 3T3, 5.3 μM in C666-1, and 17.0 μM in GM05757. Benzethonium chloride (9 μM) induces apoptosis and activates caspases after 12 hours in FaDu cells. ^[5]

Cells are seeded in 96-well plates at 5,000 per well in 100 μL of growth medium and allowed to incubate for 24 hours. Benzethonium chloride is then added, as indicated, in a total volume of 5 μL. After 48 hours, MTS assay is done according to the specifications of the manufacturer, with DMSO (0.1%)–treated cells as negative control.

Benzethonium chloride (5 mg/kg) ablates the tumor-forming ability of FaDu cells, delays the growth of xenograft tumors, and combined additively with local tumor radiation therapy in established FaDu tumors in SCID mice. ^[5]