RESUMEN
Inhibition of the proteolytic processing of hepatocyte growth factor (HGF) and macrophage stimulating protein (MSP) is an attractive approach for the drug discovery of novel anticancer therapeutics which prevent tumor progression and metastasis. Here, we utilized an improved and expanded version of positional scanning of substrate combinatorial libraries (PS-SCL) technique called HyCoSuL to optimize peptidomimetic inhibitors of the HGF/MSP activating serine proteases, HGFA, matriptase, and hepsin. These inhibitors have an electrophilic ketone serine trapping warhead and thus form a reversible covalent bond to the protease. We demonstrate that by varying the P2, P3, and P4 positions of the inhibitor with unnatural amino acids based on the protease substrate preferences learned from HyCoSuL, we can predictably modify the potency and selectivity of the inhibitor. We identified the tetrapeptide JH-1144 (8) as a single digit nM inhibitor of HGFA, matriptase and hepsin with excellent selectivity over Factor Xa and thrombin. These unnatural peptides have increased metabolic stability relative to natural peptides of similar structure. The tripeptide inhibitor PK-1-89 (2) has excellent pharmacokinetics in mice with good compound exposure out to 24 h. In addition, we obtained an X-ray structure of the inhibitor MM1132 (15) bound to matriptase revealing an interesting binding conformation useful for future inhibitor design.
Asunto(s)
Serina Endopeptidasas , Serina Endopeptidasas/química , Serina Endopeptidasas/metabolismo , Especificidad por Sustrato , Humanos , Diseño de Fármacos , Aminoácidos/química , Aminoácidos/metabolismo , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Inhibidores de Proteasas/metabolismo , Inhibidores de Serina Proteinasa/química , Inhibidores de Serina Proteinasa/farmacología , Animales , Factor de Crecimiento de Hepatocito/metabolismo , Factor de Crecimiento de Hepatocito/química , Factor de Crecimiento de Hepatocito/antagonistas & inhibidoresRESUMEN
Drought causes crop losses worldwide, and its impact is expected to increase as the world warms. This has motivated the development of small-molecule tools for mitigating the effects of drought on agriculture. We show here that current leads are limited by poor bioactivity in wheat, a widely grown staple crop, and in tomato. To address this limitation, we combined virtual screening, x-ray crystallography, and structure-guided design to develop opabactin (OP), an abscisic acid (ABA) mimic with up to an approximately sevenfold increase in receptor affinity relative to ABA and up to 10-fold greater activity in vivo. Studies in Arabidopsis thaliana reveal a role of the type III receptor PYRABACTIN RESISTANCE-LIKE 2 for the antitranspirant efficacy of OP. Thus, virtual screening and structure-guided optimization yielded newly discovered agonists for manipulating crop abiotic stress tolerance and water use.
Asunto(s)
Ácido Abscísico/análogos & derivados , Proteínas de Arabidopsis/agonistas , Arabidopsis/efectos de los fármacos , Benzamidas/farmacología , Ciclohexanos/farmacología , Hormonas/farmacología , Receptores de Superficie Celular/agonistas , Estrés Fisiológico/efectos de los fármacos , Agua/fisiología , Arabidopsis/fisiología , Benzamidas/química , Ciclohexanos/química , Sequías , Hormonas/química , Solanum lycopersicum/fisiología , Modelos Moleculares , Transpiración de Plantas/efectos de los fármacos , Triticum/fisiologíaRESUMEN
Matriptase and hepsin belong to the family of type II transmembrane serine proteases (TTSPs). Increased activity of these and the plasma protease, hepatocyte growth factor activator (HGFA), is associated with unregulated cell signaling and tumor progression through increased MET and RON kinase signaling pathways. These proteases are highly expressed in multiple solid tumors and hematological malignancies. Herein, we detail the synthesis and structure-activity relationships (SAR) of a dipeptide library bearing Arg α-ketobenozothiazole (kbt) warheads as novel inhibitors of HGFA, matriptase, and hepsin. We elucidated the substrate specificity for HGFA using positional scanning of substrate combinatorial libraries (PS-SCL), which was used to discover selective inhibitors of matriptase and hepsin. Using these selective inhibitors, we have clarified the specific role of hepsin in maintaining epithelial cell membrane integrity, known to be lost in breast cancer progression. These selective compounds are useful as chemical biology tools and for future drug discovery efforts.
Asunto(s)
Serina Endopeptidasas/química , Inhibidores de Serina Proteinasa/química , Sitios de Unión , Línea Celular Tumoral , Dipéptidos/química , Dipéptidos/metabolismo , Evaluación Preclínica de Medicamentos , Humanos , Simulación del Acoplamiento Molecular , Estructura Terciaria de Proteína , Serina Endopeptidasas/metabolismo , Inhibidores de Serina Proteinasa/metabolismo , Relación Estructura-Actividad , Especificidad por SustratoRESUMEN
Increasing drought and diminishing freshwater supplies have stimulated interest in developing small molecules that can be used to control transpiration. Receptors for the plant hormone abscisic acid (ABA) have emerged as key targets for this application, because ABA controls the apertures of stomata, which in turn regulate transpiration. Here, we describe the rational design of cyanabactin, an ABA receptor agonist that preferentially activates Pyrabactin Resistance 1 (PYR1) with low nanomolar potency. A 1.63 Å X-ray crystallographic structure of cyanabactin in complex with PYR1 illustrates that cyanabactin's arylnitrile mimics ABA's cyclohexenone oxygen and engages the tryptophan lock, a key component required to stabilize activated receptors. Further, its sulfonamide and 4-methylbenzyl substructures mimic ABA's carboxylate and C6 methyl groups, respectively. Isothermal titration calorimetry measurements show that cyanabactin's compact structure provides ready access to high ligand efficiency on a relatively simple scaffold. Cyanabactin treatments reduce Arabidopsis whole-plant stomatal conductance and activate multiple ABA responses, demonstrating that its in vitro potency translates to ABA-like activity in vivo. Genetic analyses show that the effects of cyanabactin, and the previously identified agonist quinabactin, can be abolished by the genetic removal of PYR1 and PYL1, which form subclade A within the dimeric subfamily III receptors. Thus, cyanabactin is a potent and selective agonist with a wide spectrum of ABA-like activities that defines subfamily IIIA receptors as key target sites for manipulating transpiration.
Asunto(s)
Ácido Abscísico/metabolismo , Agroquímicos/metabolismo , Proteínas de Arabidopsis/agonistas , Arabidopsis/efectos de los fármacos , Proteínas de Transporte de Membrana/agonistas , Estomas de Plantas/efectos de los fármacos , Sulfonamidas/metabolismo , Agroquímicos/química , Arabidopsis/fisiología , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Cristalografía por Rayos X , Sequías , Ligandos , Proteínas de Transporte de Membrana/química , Proteínas de Transporte de Membrana/metabolismo , Modelos Moleculares , Naftalenos/química , Naftalenos/metabolismo , Estomas de Plantas/fisiología , Bibliotecas de Moléculas Pequeñas/química , Bibliotecas de Moléculas Pequeñas/metabolismo , Sulfonamidas/químicaRESUMEN
Agricultural productivity is dictated by water availability and consequently drought is the major source of crop losses worldwide. The phytohormone abscisic acid (ABA) is elevated in response to water deficit and modulates drought tolerance by reducing water consumption and inducing other drought-protective responses. The recent identification of ABA receptors, elucidation of their structures and understanding of the core ABA signaling network has created new opportunities for agrochemical development. An unusually large gene family encodes ABA receptors and, until recently, it was unclear if selective or pan-agonists would be necessary for modulating water use. The recent identification of the selective agonist quinabactin has resolved this issue and defined Pyrabactin Resistance 1 (PYR1) and its close relatives as key targets for water use control. This review provides an overview of the structure and function of ABA receptors, progress in the development of synthetic agonists, and the use of orthogonal receptors to enable agrochemical control in transgenic plants.