Modified tetrahalogenated benzimidazoles with CK2 inhibitory activity are active against human prostate cancer cells LNCaP in vitro

A series of novel CK2 inhibitors, tetrahalogenated benzimidazoles carrying an aminoalkylamino group at position 2, has been prepared by nucleophilic substitution of the respective 2,4,5,6,7-pentabromobenzimidazoles and 2-bromo-4,5,6,7-tetraiodobenzimidazoles. The new derivatives as well as some previously obtained tetrahalogenobenzimidazoles, including 4,5,6,7-tetrabromobenzimidazole (TBI) and 4,5,6,7-tetraiodobenzimidazole (TIBI), were evaluated for activity against the hormone-sensitive human prostate cancer cell line LNCaP. The activity of 2-aminoalkylamino derivatives was notably higher (LD50 4.75–9.37μM) than that of TBI and TIBI (LD50≈20μM). The determination of the LD50 value identified the 2-aminoethylamino-4,5,6,7-tetraiodobenzimidazole with an additional methyl group at position 1 (6) as the most efficient compound (LD50: 4.75±1.02μM). Interestingly, there was no clear correlation between cell viability and apoptosis induction indicating additional cell death mechanisms.