RESUMEN
Fluorination of metabolic hotspots in a molecule is a common medicinal chemistry strategy to improve in vivo half-life and exposure and, generally, this strategy offers significant benefits. Here, we report the application of this strategy to a series of poly-ADP ribose glycohydrolase (PARG) inhibitors, resulting in unexpected in vivo toxicity which was attributed to this single-atom modification.
Asunto(s)
Ciclopropanos/farmacología , Glicósido Hidrolasas/toxicidad , Microsomas Hepáticos/efectos de los fármacos , Administración Oral , Animales , Ciclopropanos/administración & dosificación , Ciclopropanos/química , Ciclopropanos/farmacocinética , Glicósido Hidrolasas/administración & dosificación , Glicósido Hidrolasas/química , Glicósido Hidrolasas/farmacocinética , Semivida , Humanos , Ratones , Microsomas Hepáticos/metabolismoRESUMEN
DNA damage repair enzymes are promising targets in the development of new therapeutic agents for a wide range of cancers and potentially other diseases. The enzyme poly(ADP-ribose) glycohydrolase (PARG) plays a pivotal role in the regulation of DNA repair mechanisms; however, the lack of potent drug-like inhibitors for use in cellular and in vivo models has limited the investigation of its potential as a novel therapeutic target. Using the crystal structure of human PARG in complex with the weakly active and cytotoxic anthraquinone 8a, novel quinazolinedione sulfonamides PARG inhibitors have been identified by means of structure-based virtual screening and library design. 1-Oxetan-3-ylmethyl derivatives 33d and 35d were selected for preliminary investigations in vivo. X-ray crystal structures help rationalize the observed structure-activity relationships of these novel inhibitors.
Asunto(s)
Reparación del ADN , Diseño de Fármacos , Inhibidores de Glicósido Hidrolasas/química , Inhibidores de Glicósido Hidrolasas/farmacología , Glicósido Hidrolasas/antagonistas & inhibidores , Quinazolinonas/química , Quinazolinonas/farmacología , Administración Oral , Animales , Disponibilidad Biológica , Dominio Catalítico , Inhibidores de Glicósido Hidrolasas/administración & dosificación , Inhibidores de Glicósido Hidrolasas/farmacocinética , Glicósido Hidrolasas/química , Glicósido Hidrolasas/metabolismo , Células HeLa , Humanos , Masculino , Ratones , Modelos Moleculares , Quinazolinonas/administración & dosificación , Quinazolinonas/farmacocinética , Relación Estructura-ActividadRESUMEN
Inhibition of lysine specific demethylase 1 (LSD1) has been shown to induce the differentiation of leukemia stem cells in acute myeloid leukemia (AML). Irreversible inhibitors developed from the nonspecific inhibitor tranylcypromine have entered clinical trials; however, the development of effective reversible inhibitors has proved more challenging. Herein, we describe our efforts to identify reversible inhibitors of LSD1 from a high throughput screen and subsequent in silico modeling approaches. From a single hit (12) validated by biochemical and biophysical assays, we describe our efforts to develop acyclic scaffold-hops from GSK-690 (1). A further scaffold modification to a (4-cyanophenyl)glycinamide (e.g., 29a) led to the development of compound 32, with a Kd value of 32 nM and an EC50 value of 0.67 µM in a surrogate cellular biomarker assay. Moreover, this derivative does not display the same level of hERG liability as observed with 1 and represents a promising lead for further development.
Asunto(s)
Antineoplásicos/síntesis química , Antineoplásicos/farmacología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Glicina/análogos & derivados , Histona Demetilasas/antagonistas & inhibidores , Leucemia/tratamiento farmacológico , Compuestos de Espiro/farmacología , Biomarcadores , Línea Celular Tumoral , Simulación por Computador , Diseño de Fármacos , Descubrimiento de Drogas , Canales de Potasio Éter-A-Go-Go/efectos de los fármacos , Glicina/síntesis química , Glicina/farmacología , Ensayos Analíticos de Alto Rendimiento , Humanos , Modelos Moleculares , Simulación del Acoplamiento Molecular , Compuestos de Espiro/síntesis química , Relación Estructura-Actividad , Tranilcipromina/análogos & derivados , Tranilcipromina/química , Tranilcipromina/farmacologíaRESUMEN
As part of our ongoing efforts to develop reversible inhibitors of LSD1, we identified a series of 4-(pyrrolidin-3-yl)benzonitrile derivatives that act as successful scaffold-hops of the literature inhibitor GSK-690. The most active compound, 21g, demonstrated a Kd value of 22nM and a biochemical IC50 of 57nM. In addition, this compound displayed improved selectivity over the hERG ion channel compared to GSK-690, and no activity against the related enzymes MAO-A and B. In human THP-1 acute myeloid leukaemia cells, 21g was found to increase the expression of the surrogate cellular biomarker CD86. This work further demonstrates the versatility of scaffold-hopping asa method to develop structurally diverse, potent inhibitors of LSD1.
Asunto(s)
Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Histona Demetilasas/antagonistas & inhibidores , Nitrilos/química , Nitrilos/farmacología , Sitios de Unión , Línea Celular Tumoral , Diseño de Fármacos , Activación Enzimática/efectos de los fármacos , Inhibidores Enzimáticos/síntesis química , Histona Demetilasas/metabolismo , Humanos , Concentración 50 Inhibidora , Simulación del Acoplamiento Molecular , Nitrilos/síntesis química , Estructura Terciaria de Proteína , Pirrolidinas/química , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
A series of reversible inhibitors of lysine specific demethylase 1 (LSD1) with a 5-hydroxypyrazole scaffold have been developed from compound 7, which was identified from the patent literature. Surface plasmon resonance (SPR) and biochemical analysis showed it to be a reversible LSD1 inhibitor with an IC50 value of 0.23µM. Optimisation of this compound by rational design afforded compounds with Kd values of <10nM. In human THP-1 cells, these compounds were found to upregulate the expression of the surrogate cellular biomarker CD86. Compound 11p was found to have moderate oral bioavailability in mice suggesting its potential for use as an in vivo tool compound.
Asunto(s)
Histona Demetilasas/antagonistas & inhibidores , Pirazoles/química , Animales , Antígeno B7-2/metabolismo , Sitios de Unión , Dominio Catalítico , Diferenciación Celular/efectos de los fármacos , Línea Celular , Semivida , Histona Demetilasas/metabolismo , Humanos , Concentración 50 Inhibidora , Ratones , Simulación del Acoplamiento Molecular , Pirazoles/síntesis química , Pirazoles/farmacocinética , Pirazoles/farmacología , Relación Estructura-Actividad , Resonancia por Plasmón de SuperficieRESUMEN
The enzyme poly(ADP-ribose) glycohydrolase (PARG) performs a critical role in the repair of DNA single strand breaks (SSBs). However, a detailed understanding of its mechanism of action has been hampered by a lack of credible, cell-active chemical probes. Herein, we demonstrate inhibition of PARG with a small molecule, leading to poly(ADP-ribose) (PAR) chain persistence in intact cells. Moreover, we describe two advanced, and chemically distinct, cell-active tool compounds with convincing on-target pharmacology and selectivity. Using one of these tool compounds, we demonstrate pharmacology consistent with PARG inhibition. Further, while the roles of PARG and poly(ADP-ribose) polymerase (PARP) are closely intertwined, we demonstrate that the pharmacology of a PARG inhibitor differs from that observed with the more thoroughly studied PARP inhibitor olaparib. We believe that these tools will facilitate a wider understanding of this important component of DNA repair and may enable the development of novel therapeutic agents exploiting the critical dependence of tumors on the DNA damage response (DDR).
Asunto(s)
Reparación del ADN , Glicósido Hidrolasas/química , Sondas Moleculares/química , Ftalazinas/farmacología , Piperazinas/farmacología , Inhibidores Enzimáticos/farmacología , Glicósido Hidrolasas/antagonistas & inhibidores , Células HeLa , Humanos , Resonancia por Plasmón de SuperficieRESUMEN
In the 10 years since the discovery of lysine-specific demethylase 1 (LSD1), this epigenetic eraser has emerged as an important target of interest in oncology. More specifically, research has demonstrated that it plays an essential role in the self-renewal of leukemic stem cells in acute myeloid leukemia (AML). This review will cover clinical aspects of AML, the role of epigenetics in the disease, and discuss the research that led to the first irreversible inhibitors of LSD1 entering clinical trials for the treatment of AML in 2014. We also review recent achievements and progress in the development of potent and selective reversible inhibitors of LSD1. These compounds differ in their mode of action from tranylcypromine derivatives and could facilitate novel biochemical studies to probe the pathways mediated by LSD1. In this review, we will critically evaluate the strengths and weaknesses of published series of reversible LSD1 inhibitors. Overall, while the development of reversible inhibitors to date has been less fruitful than that of irreversible inhibitors, there is still the possibility for their use to facilitate further research into the roles and functions of LSD1 and to expand the therapeutic applications of LSD1 inhibitors in the clinic.
Asunto(s)
Histona Demetilasas/química , Leucemia Mieloide Aguda/tratamiento farmacológico , Lisina/química , Animales , Antineoplásicos/química , Diseño de Fármacos , Ensayos de Selección de Medicamentos Antitumorales , Epigénesis Genética , Regulación Leucémica de la Expresión Génica , Humanos , Concentración 50 Inhibidora , Ratones , Poliaminas/química , Resultado del TratamientoRESUMEN
The recently discovered enzyme tyrosyl-DNA phosphodiesterase 2 (TDP2) has been implicated in the topoisomerase-mediated repair of DNA damage. In the clinical setting, it has been hypothesized that TDP2 may mediate drug resistance to topoisomerase II (topo II) inhibition by etoposide. Therefore, selective pharmacological inhibition of TDP2 is proposed as a novel approach to overcome intrinsic or acquired resistance to topo II-targeted drug therapy. Following a high-throughput screening (HTS) campaign, toxoflavins and deazaflavins were identified as the first reported sub-micromolar and selective inhibitors of this enzyme. Toxoflavin derivatives appeared to exhibit a clear structure-activity relationship (SAR) for TDP2 enzymatic inhibition. However, we observed a key redox liability of this series, and this, alongside early in vitro drug metabolism and pharmacokinetics (DMPK) issues, precluded further exploration. The deazaflavins were developed from a singleton HTS hit. This series showed distinct SAR and did not display redox activity; however low cell permeability proved to be a challenge.
Asunto(s)
Hidrolasas Diéster Fosfóricas/efectos de los fármacos , Pirimidinonas/farmacología , Inhibidores de Topoisomerasa II/farmacología , Triazinas/farmacología , Relación Estructura-Actividad , Inhibidores de Topoisomerasa II/químicaRESUMEN
The first examples of heterocycle synthesis by iminophosphorane formation/intramolecular aza-Wittig cyclizations that are catalytic in the organophosphorus component are reported. The reaction has been demonstrated in the synthesis of both azine (phenanthridine) and azole (benzoxazole) heterocycles. Catalyst loadings down to 1 mol % have been used with little or no loss in reaction efficiency. The intimate involvement of the phosphine oxide in the catalytic cycle has been verified by in situ infrared spectroscopy.