RESUMO
The peptidyl prolyl cis/trans isomerase Pin1 is a promising molecular target for anti-cancer therapeutics. Here we report the structure-guided evolution of an indole 2-carboxylic acid fragment hit into a series of alpha-benzimidazolyl-substituted amino acids. Examples inhibited Pin1 activity with IC(50) <100nM, but were inactive on cells. Replacement of the benzimidazole ring with a naphthyl group resulted in a 10-50-fold loss in ligand potency, but these examples downregulated biomarkers of Pin1 activity and blocked proliferation of PC3 cells.
Assuntos
Aminoácidos/química , Antineoplásicos/química , Inibidores Enzimáticos/química , Peptidilprolil Isomerase/antagonistas & inibidores , Aminoácidos/síntese química , Aminoácidos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Benzimidazóis/química , Sítios de Ligação , Linhagem Celular Tumoral , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Ligação de Hidrogênio , Indóis/química , Peptidilprolil Isomerase de Interação com NIMA , Peptidilprolil Isomerase/metabolismo , Relação Estrutura-AtividadeRESUMO
The targeting of RNA for the design of novel anti-viral compounds represents an area of vast potential. We have used NMR and computational methods to model the interaction of a series of synthetic inhibitors of the in vitro RNA binding activities of a peptide derived from the transcriptional activator protein, Tat, from human immunodeficiency virus type 1. Inhibition has been measured through the monitering of fluorescence resonance energy transfer between fluorescently labeled peptide and RNA components. A series of compounds containing a bi-aryl heterocycle as one of the three substituents on a benzylic scaffold, induce a novel, inactive TAR conformation by stacking between base-pairs at the site of a three-base bulge within TAR. The development of this series resulted in an enhancement in potency (with Ki < 100 nM in an in vitro assay) and the removal of problematic guanidinium moieties. Ligands from this series can act as inhibitors of Tat-induced transcription in a cell-free system. This study validates the drug design strategy of using a ligand to target the RNA receptor in a non-functional conformation.