2-Phenyl-1-[4-(2-piperidine-1-yl-ethoxy)benzyl]-1H-benzimidazoles as ligands for the estrogen receptor: Synthesis and pharmacological evaluation

2-Phenyl-1H-benzimidazoles 7a–e were synthesized and tested for gene activation on ERα-positive MCF-7 breast cancer cells, stably transfected with the reporter plasmid ERE_wtcluc (MCF-7-2a cells). None of the compounds showed agonistic properties, but they antagonized dependent on hydroxyl groups at the benzimidazole core (5- or 6-OH) and at the aromatic ring in the 2-position (4-OH) in high concentrations the gene activation induced by estradiol (E2, 1 nM). All compounds exhibited significant antiproliferative properties on MCF-7 cells but they were inactive against hormone independent, ER negative MDA-MB-231 cells.