RESUMEN
The design of potent Pin1 inhibitors has been challenging because its active site specifically recognizes a phospho-protein epitope. The de novo design of phosphate-based Pin1 inhibitors focusing on the phosphate recognition pocket and the successful replacement of the phosphate group with a carboxylate have been previously reported. The potency of the carboxylate series is now further improved through structure-based optimization of ligand-protein interactions in the proline binding site which exploits the H-bond interactions necessary for Pin1 catalytic function. Further optimization using a focused library approach led to the discovery of low nanomolar non-phosphate small molecular Pin1 inhibitors. Structural modifications designed to improve cell permeability resulted in Pin1 inhibitors with low micromolar anti-proliferative activities against cancer cells.
Asunto(s)
Bencimidazoles/farmacología , Ácidos Carboxílicos/farmacología , Inhibidores Enzimáticos/farmacología , Isomerasa de Peptidilprolil/antagonistas & inhibidores , Fosfatos/química , Bencimidazoles/síntesis química , Bencimidazoles/química , Ácidos Carboxílicos/síntesis química , Ácidos Carboxílicos/química , Dominio Catalítico/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Estructura Molecular , Peptidilprolil Isomerasa de Interacción con NIMA , Isomerasa de Peptidilprolil/metabolismo , Relación Estructura-ActividadRESUMEN
Despite abundant evidence that aberrant Rho-family GTPase activation contributes to most steps of cancer initiation and progression, there is a dearth of inhibitors of their effectors (e.g., p21-activated kinases). Through high-throughput screening and structure-based design, we identify PF-3758309, a potent (K(d) = 2.7 nM), ATP-competitive, pyrrolopyrazole inhibitor of PAK4. In cells, PF-3758309 inhibits phosphorylation of the PAK4 substrate GEF-H1 (IC(50) = 1.3 nM) and anchorage-independent growth of a panel of tumor cell lines (IC(50) = 4.7 +/- 3 nM). The molecular underpinnings of PF-3758309 biological effects were characterized using an integration of traditional and emerging technologies. Crystallographic characterization of the PF-3758309/PAK4 complex defined determinants of potency and kinase selectivity. Global high-content cellular analysis confirms that PF-3758309 modulates known PAK4-dependent signaling nodes and identifies unexpected links to additional pathways (e.g., p53). In tumor models, PF-3758309 inhibits PAK4-dependent pathways in proteomic studies and regulates functional activities related to cell proliferation and survival. PF-3758309 blocks the growth of multiple human tumor xenografts, with a plasma EC(50) value of 0.4 nM in the most sensitive model. This study defines PAK4-related pathways, provides additional support for PAK4 as a therapeutic target with a unique combination of functions (apoptotic, cytoskeletal, cell-cycle), and identifies a potent, orally available small-molecule PAK inhibitor with significant promise for the treatment of human cancers.
Asunto(s)
Proliferación Celular/efectos de los fármacos , Modelos Moleculares , Neoplasias/metabolismo , Pirazoles/farmacología , Pirroles/farmacología , Transducción de Señal/efectos de los fármacos , Quinasas p21 Activadas/antagonistas & inhibidores , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Cristalografía , Factores de Intercambio de Guanina Nucleótido/metabolismo , Humanos , Neoplasias/tratamiento farmacológico , Fosforilación/efectos de los fármacos , Pirazoles/química , Pirazoles/metabolismo , Pirroles/química , Pirroles/metabolismo , Factores de Intercambio de Guanina Nucleótido RhoRESUMEN
Pin1 is a member of the cis-trans peptidyl-prolyl isomerase family with potential anti-cancer therapeutic value. Here we report structure-based de novo design and optimization of novel Pin1 inhibitors. Without a viable lead from internal screenings, we designed a series of novel Pin1 inhibitors by interrogating and exploring a protein crystal structure of Pin1. The ligand efficiency of the initial concept molecule was optimized with integrated SBDD and parallel chemistry approaches, resulting in a more attractive lead series.
Asunto(s)
Inhibidores Enzimáticos/química , Isomerasa de Peptidilprolil/antagonistas & inhibidores , Secuencia de Aminoácidos , Sitios de Unión , Técnicas Químicas Combinatorias , Simulación por Computador , Cristalografía por Rayos X , Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Humanos , Peptidilprolil Isomerasa de Interacción con NIMA , Isomerasa de Peptidilprolil/metabolismo , Relación Estructura-ActividadRESUMEN
The P21-activated kinases (PAK) are emerging antitumor therapeutic targets. In this paper, we describe the discovery of potent PAK inhibitors guided by structure-based drug design. In addition, the efflux of the pyrrolopyrazole series was effectively reduced by applying multiple medicinal chemistry strategies, leading to a series of PAK inhibitors that are orally active in inhibiting tumor growth in vivo.