Heptamidine

Heptamidine (SBi4211) is a potent Pentamidine-related inhibitor of the calcium-binding protein S100B (K_d=6.9 μM), selectively kills melanoma cells with S100B over those without S100B^[1]. Heptamidine is a useful tool for the investigation of Myotonic dystrophy (DM)^[2]. IC50 & Target: Kd: 6.9 μM (calcium-binding protein S100B)^[1] In Vitro: Heptamidine is a Pentamidine-S100B complex, two molecules of pentamidine bind per monomer of S100B, which performs to be an inhibitor for S100B^[1].
Heptamidine (20 μM) does not decrease CUG levels?significantly when compares to Propamidine and Pentamidine, and exhibits cytotoxic at concentrations above 17.5 μM in HeLa cells expressing 960 CUG repeats^[2].
Heptamidine rescues mis-splicing of minigene reporters in a HeLa cell DM1 model with an EC₅₀ value of 15 μM^[2].
In Vivo: Heptamidine (intraperitoneal injection; 20 or 30 mg/kg; 7 days) causes a dose-dependent reduction of exon 7a inclusion in?HSALR?mice, returning to wild type levels (6±1%) when at 20 mg/kg dose, the myotonia is reduced from grade 3 to grade 1 (occasional myotonic discharge) or grade 0 at both 20 or 30 mg/kg^[2].