RESUMEN
The 3 human RAS genes, KRAS, NRAS, and HRAS, encode 4 different RAS proteins which belong to the protein family of small GTPases that function as binary molecular switches involved in cell signaling. Activating mutations in RAS are among the most common oncogenic drivers in human cancers, with KRAS being the most frequently mutated oncogene. Although KRAS is an excellent drug discovery target for many cancers, and despite decades of research, no therapeutic agent directly targeting RAS has been clinically approved. Using structure-based drug design, we have discovered BI-2852 (1), a KRAS inhibitor that binds with nanomolar affinity to a pocket, thus far perceived to be "undruggable," between switch I and II on RAS; 1 is mechanistically distinct from covalent KRASG12C inhibitors because it binds to a different pocket present in both the active and inactive forms of KRAS. In doing so, it blocks all GEF, GAP, and effector interactions with KRAS, leading to inhibition of downstream signaling and an antiproliferative effect in the low micromolar range in KRAS mutant cells. These findings clearly demonstrate that this so-called switch I/II pocket is indeed druggable and provide the scientific community with a chemical probe that simultaneously targets the active and inactive forms of KRAS.
Asunto(s)
Descubrimiento de Drogas , Preparaciones Farmacéuticas/química , Proteínas Proto-Oncogénicas p21(ras)/química , Guanosina Trifosfato/metabolismo , Humanos , Modelos Moleculares , Nanopartículas/químicaRESUMEN
Targeting subunits of BAF/PBAF chromatin remodeling complexes has been proposed as an approach to exploit cancer vulnerabilities. Here, we develop proteolysis targeting chimera (PROTAC) degraders of the BAF ATPase subunits SMARCA2 and SMARCA4 using a bromodomain ligand and recruitment of the E3 ubiquitin ligase VHL. High-resolution ternary complex crystal structures and biophysical investigation guided rational and efficient optimization toward ACBI1, a potent and cooperative degrader of SMARCA2, SMARCA4 and PBRM1. ACBI1 induced anti-proliferative effects and cell death caused by SMARCA2 depletion in SMARCA4 mutant cancer cells, and in acute myeloid leukemia cells dependent on SMARCA4 ATPase activity. These findings exemplify a successful biophysics- and structure-based PROTAC design approach to degrade high profile drug targets, and pave the way toward new therapeutics for the treatment of tumors sensitive to the loss of BAF complex ATPases.
Asunto(s)
Ensamble y Desensamble de Cromatina/genética , Proteínas de Unión al ADN/genética , Leucemia Mieloide Aguda/genética , Proteínas Nucleares/genética , Proliferación Celular , Células Cultivadas , Proteínas de Unión al ADN/metabolismo , Humanos , Leucemia Mieloide Aguda/metabolismo , Estructura Molecular , Proteínas Nucleares/metabolismoRESUMEN
In the version of this article originally published, several lines of text in the last paragraph of the right column on page 1 of the PDF were transposed into the bottom paragraph of the left column. The affected text of the left column should read "The ATP-dependent activities of the BAF (SWI/SNF) chromatin remodeling complexes affect the positioning of nucleosomes on DNA and thereby many cellular processes related to chromatin structure, including transcription, DNA repair and decatenation of chromosomes during mitosis12,13." The affected text of the right column should read "SMARCA2/4BD inhibitors are thus precluded from use for the treatment of SMARCA4 mutant cancers but could provide attractive ligands for PROTAC conjugation. Small molecules binding to other bromodomains have been successfully converted into PROTACs by conjugating them with structures capable of binding to the E3 ligases von Hippel-Lindau (VHL) or cereblon5,6,10,11,25,26,27." The errors have been corrected in the PDF version of the paper.
RESUMEN
Here, we report the fragment-based discovery of BI-9321, a potent, selective and cellular active antagonist of the NSD3-PWWP1 domain. The human NSD3 protein is encoded by the WHSC1L1 gene located in the 8p11-p12 amplicon, frequently amplified in breast and squamous lung cancer. Recently, it was demonstrated that the PWWP1 domain of NSD3 is required for the viability of acute myeloid leukemia cells. To further elucidate the relevance of NSD3 in cancer biology, we developed a chemical probe, BI-9321, targeting the methyl-lysine binding site of the PWWP1 domain with sub-micromolar in vitro activity and cellular target engagement at 1 µM. As a single agent, BI-9321 downregulates Myc messenger RNA expression and reduces proliferation in MOLM-13 cells. This first-in-class chemical probe BI-9321, together with the negative control BI-9466, will greatly facilitate the elucidation of the underexplored biological function of PWWP domains.
Asunto(s)
N-Metiltransferasa de Histona-Lisina/antagonistas & inhibidores , Proteínas Nucleares/antagonistas & inhibidores , Sistemas CRISPR-Cas , Línea Celular , Proliferación Celular/efectos de los fármacos , Supervivencia Celular , Regulación de la Expresión Génica/efectos de los fármacos , N-Metiltransferasa de Histona-Lisina/genética , N-Metiltransferasa de Histona-Lisina/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Dominios Proteicos , Proteínas Proto-Oncogénicas c-myc/genética , Proteínas Proto-Oncogénicas c-myc/metabolismoRESUMEN
Here we show that acute myeloid leukemia (AML) cells require the BRD9 subunit of the SWI-SNF chromatin-remodeling complex to sustain MYC transcription, rapid cell proliferation and a block in differentiation. Based on these observations, we derived small-molecule inhibitors of the BRD9 bromodomain that selectively suppress the proliferation of mouse and human AML cell lines. To establish these effects as on-target, we engineered a bromodomain-swap allele of BRD9 that retains functionality despite a radically altered bromodomain pocket. Expression of this allele in AML cells confers resistance to the antiproliferative effects of our compound series, thus establishing BRD9 as the relevant cellular target. Furthermore, we used an analogous domain-swap strategy to generate an inhibitor-resistant allele of EZH2. To our knowledge, our study provides the first evidence for a role of BRD9 in cancer and reveals a simple genetic strategy for constructing resistance alleles to demonstrate on-target activity of chemical probes in cells.
Asunto(s)
Antineoplásicos/farmacología , Ingeniería Celular , Resistencia a Antineoplásicos/efectos de los fármacos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/patología , Factores de Transcripción/antagonistas & inhibidores , Alelos , Animales , Antineoplásicos/química , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Leucemia Mieloide Aguda/metabolismo , Ratones , Modelos Moleculares , Estructura Molecular , Relación Estructura-Actividad , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Identifying promising chemical starting points for small molecule inhibitors of active, GTP-loaded KRAS "on" remains of great importance to clinical oncology and represents a significant challenge in medicinal chemistry. Here, we describe broadly applicable learnings from a KRAS hit finding campaign: While we initially identified KRAS inhibitors in a biochemical high-throughput screen, we later discovered that compound potencies were all but assay artifacts linked to metal salts interfering with KRAS AlphaScreen assay technology. The source of the apparent biochemical KRAS inhibition was ultimately traced to unavoidable palladium impurities from chemical synthesis. This discovery led to the development of a Metal Ion Interference Set (MIIS) for up-front assay development and testing. Profiling of the MIIS across 74 assays revealed a reduced interference liability of label-free biophysical assays and, as a result, provided general estimates for luminescence- and fluorescence-based assay susceptibility to metal salt interference.
Asunto(s)
Paladio , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Proteínas Proto-Oncogénicas p21(ras)/antagonistas & inhibidores , Proteínas Proto-Oncogénicas p21(ras)/genética , Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Paladio/química , Ensayos Analíticos de Alto Rendimiento/métodos , Sales (Química)/químicaRESUMEN
Targeted protein degradation has recently emerged as a novel option in drug discovery. Natural protein half-life is expected to affect the efficacy of degrading agents, but to what extent it influences target protein degradation has not been systematically explored. Using simple mathematical modeling of protein degradation, we find that the natural half-life of a target protein has a dramatic effect on the level of protein degradation induced by a degrader agent which can pose significant hurdles to screening efforts. Moreover, we show that upon screening for degraders of short-lived proteins, agents that stall protein synthesis, such as GSPT1 degraders and generally cytotoxic compounds, deceptively appear as protein-degrading agents. This is exemplified by the disappearance of short-lived proteins such as MCL1 and MDM2 upon GSPT1 degradation and upon treatment with cytotoxic agents such as doxorubicin. These findings have implications for target selection as well as for the type of control experiments required to conclude that a novel agent works as a bona fide targeted protein degrader.
Asunto(s)
Proteolisis , Humanos , Proteínas Proto-Oncogénicas c-mdm2/metabolismo , Semivida , Doxorrubicina/farmacología , Doxorrubicina/metabolismo , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Proteínas/metabolismo , Proteínas/químicaRESUMEN
The bromodomain and PHD-finger containing transcription factor (BPTF) is part of the nucleosome remodeling factor (NURF) complex and has been implicated in multiple cancer types. Here, we report the discovery of a potent and selective chemical probe targeting the bromodomain of BPTF with an attractive pharmacokinetic profile enabling cellular and inâ vivo experiments in mice. Microarray-based transcriptomics in presence of the probe in two lung cancer cell lines revealed only minor effects on the transcriptome. Profiling against a panel of cancer cell lines revealed that the antiproliferative effect does not correlate with BPTF dependency score in depletion screens. Both observations and the multi-domain architecture of BPTF suggest that depleting the protein by proteolysis targeting chimeras (PROTACs) could be a promising strategy to target cancer cell proliferation. We envision that the presented chemical probe and the related negative control will enable the research community to further explore scientific hypotheses with respect to BPTF bromodomain inhibition.
Asunto(s)
Neoplasias Pulmonares , Factores de Transcripción , Animales , Ratones , Proliferación Celular , Regulación de la Expresión Génica , Proteínas Nucleares/metabolismo , Factores de Transcripción/metabolismoRESUMEN
Targeted protein degradation offers an alternative modality to classical inhibition and holds the promise of addressing previously undruggable targets to provide novel therapeutic options for patients. Heterobifunctional molecules co-recruit a target protein and an E3 ligase, resulting in ubiquitylation and proteosome-dependent degradation of the target. In the clinic, the oral route of administration is the option of choice but has only been achieved so far by CRBN- recruiting bifunctional degrader molecules. We aimed to achieve orally bioavailable molecules that selectively degrade the BAF Chromatin Remodelling complex ATPase SMARCA2 over its closely related paralogue SMARCA4, to allow in vivo evaluation of the synthetic lethality concept of SMARCA2 dependency in SMARCA4-deficient cancers. Here we outline structure- and property-guided approaches that led to orally bioavailable VHL-recruiting degraders. Our tool compound, ACBI2, shows selective degradation of SMARCA2 over SMARCA4 in ex vivo human whole blood assays and in vivo efficacy in SMARCA4-deficient cancer models. This study demonstrates the feasibility for broadening the E3 ligase and physicochemical space that can be utilised for achieving oral efficacy with bifunctional molecules.
Asunto(s)
Adenosina Trifosfatasas , Factores de Transcripción , Adenosina Trifosfatasas/genética , Adenosina Trifosfatasas/metabolismo , ADN Helicasas/genética , ADN Helicasas/metabolismo , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteolisis , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/genética , Proteína Supresora de Tumores del Síndrome de Von Hippel-Lindau/metabolismoRESUMEN
Activating mutations in KRAS are the most frequent oncogenic alterations in cancer. The oncogenic hotspot position 12, located at the lip of the switch II pocket, offers a covalent attachment point for KRASG12C inhibitors. To date, KRASG12C inhibitors have been discovered by first covalently binding to the cysteine at position 12 and then optimizing pocket binding. We report on the discovery of the in vivo active KRASG12C inhibitor BI-0474 using a different approach, in which small molecules that bind reversibly to the switch II pocket were identified and then optimized for non-covalent binding using structure-based design. Finally, the Michael acceptor containing warhead was attached. Our approach offers not only an alternative approach to discovering KRASG12C inhibitors but also provides a starting point for the discovery of inhibitors against other oncogenic KRAS mutants.
Asunto(s)
Neoplasias , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Proteínas Proto-Oncogénicas p21(ras)/genética , Genes ras , Mutación , Neoplasias/genética , CisteínaRESUMEN
Oncogenic alterations in human epidermal growth factor receptor 2 (HER2) occur in approximately 2% of patients with non-small cell lung cancer and predominantly affect the tyrosine kinase domain and cluster in exon 20 of the ERBB2 gene. Most clinical-grade tyrosine kinase inhibitors are limited by either insufficient selectivity against wild-type (WT) epidermal growth factor receptor (EGFR), which is a major cause of dose-limiting toxicity or by potency against HER2 exon 20 mutant variants. Here we report the discovery of covalent tyrosine kinase inhibitors that potently inhibit HER2 exon 20 mutants while sparing WT EGFR, which reduce tumor cell survival and proliferation in vitro and result in regressions in preclinical xenograft models of HER2 exon 20 mutant non-small cell lung cancer, concomitant with inhibition of downstream HER2 signaling. Our results suggest that HER2 exon 20 insertion-driven tumors can be effectively treated by a potent and highly selective HER2 inhibitor while sparing WT EGFR, paving the way for clinical translation.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Neoplasias Pulmonares , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Receptores ErbB/genética , Exones/genética , Genes erbB-2 , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Receptor ErbB-2/genéticaRESUMEN
The ubiquitin-like protein SUMO-1 (small ubiquitin-related modifier 1) is covalently attached to substrate proteins by ligases and cleaved by isopeptidases. Yeast has two SUMO-1-deconjugating enzymes, Ulp1 and Ulp2, which are located at nuclear pores and in the nucleoplasm, respectively. Here we show that the catalytic C-domain of Ulp1 must be excluded from the nucleoplasm for cell viability. This is achieved by the noncatalytic N-domain, which tethers Ulp1 to the nuclear pores. The bulk of cellular Ulp1 is not associated with nucleoporins but instead associates with three karyopherins (Pse1, Kap95 and Kap60), in a complex that is not dissociated by RanGTP in vitro. The Ulp1 N-domain has two distinct binding sites for Pse1 and Kap95/Kap60, both of which are required for anchoring to the nuclear pore complex. We propose that Ulp1 is tethered to the nuclear pores by a Ran-insensitive interaction with karyopherins associated with nucleoporins. This location could allow Ulp1 to remove SUMO-1 from sumoylated cargo proteins during their passage through the nuclear pore channel.
Asunto(s)
Transporte Activo de Núcleo Celular/fisiología , Cisteína Endopeptidasas/metabolismo , Carioferinas/metabolismo , Poro Nuclear/fisiología , Saccharomyces cerevisiae/fisiología , Transporte Biológico , Cisteína Endopeptidasas/genética , Genes Dominantes , Genes Letales , Proteína SUMO-1/metabolismo , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismoRESUMEN
KRAS, the most common oncogenic driver in human cancers, is controlled and signals primarily through protein-protein interactions (PPIs). The interaction between KRAS and SOS1, crucial for the activation of KRAS, is a typical, challenging PPI with a large contact surface area and high affinity. Here, we report that the addition of only one atom placed between Y884SOS1 and A73KRAS is sufficient to convert SOS1 activators into SOS1 inhibitors. We also disclose the discovery of BI-3406. Combination with the upstream EGFR inhibitor afatinib shows in vivo efficacy against KRASG13D mutant colorectal tumor cells, demonstrating the utility of BI-3406 to probe SOS1 biology. These findings challenge the dogma that large molecules are required to disrupt challenging PPIs. Instead, a "foot in the door" approach, whereby single atoms or small functional groups placed between key PPI interactions, can lead to potent inhibitors even for challenging PPIs such as SOS1-KRAS.
Asunto(s)
Proteínas Proto-Oncogénicas p21(ras)/metabolismo , Proteína SOS1/metabolismo , Afatinib/química , Afatinib/metabolismo , Afatinib/uso terapéutico , Regulación Alostérica/efectos de los fármacos , Sitios de Unión , Dominio Catalítico , Neoplasias Colorrectales/tratamiento farmacológico , Neoplasias Colorrectales/patología , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/metabolismo , Humanos , Simulación de Dinámica Molecular , Mutagénesis Sitio-Dirigida , Mapas de Interacción de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas p21(ras)/antagonistas & inhibidores , Proteínas Proto-Oncogénicas p21(ras)/genética , Quinazolinas/química , Quinazolinas/metabolismo , Quinazolinas/farmacología , Quinazolinas/uso terapéutico , Proteína SOS1/agonistas , Proteína SOS1/antagonistas & inhibidores , Proteína SOS1/genéticaRESUMEN
KRAS is the most frequently mutated driver of pancreatic, colorectal, and non-small cell lung cancers. Direct KRAS blockade has proved challenging, and inhibition of a key downstream effector pathway, the RAF-MEK-ERK cascade, has shown limited success because of activation of feedback networks that keep the pathway in check. We hypothesized that inhibiting SOS1, a KRAS activator and important feedback node, represents an effective approach to treat KRAS-driven cancers. We report the discovery of a highly potent, selective, and orally bioavailable small-molecule SOS1 inhibitor, BI-3406, that binds to the catalytic domain of SOS1, thereby preventing the interaction with KRAS. BI-3406 reduces formation of GTP-loaded RAS and limits cellular proliferation of a broad range of KRAS-driven cancers. Importantly, BI-3406 attenuates feedback reactivation induced by MEK inhibitors and thereby enhances sensitivity of KRAS-dependent cancers to MEK inhibition. Combined SOS1 and MEK inhibition represents a novel and effective therapeutic concept to address KRAS-driven tumors. SIGNIFICANCE: To date, there are no effective targeted pan-KRAS therapies. In-depth characterization of BI-3406 activity and identification of MEK inhibitors as effective combination partners provide an attractive therapeutic concept for the majority of KRAS-mutant cancers, including those fueled by the most prevalent mutant KRAS oncoproteins, G12D, G12V, G12C, and G13D.See related commentary by Zhao et al., p. 17.This article is highlighted in the In This Issue feature, p. 1.
Asunto(s)
Neoplasias Pulmonares , Proteínas Proto-Oncogénicas p21(ras) , Línea Celular Tumoral , Humanos , Quinasas de Proteína Quinasa Activadas por Mitógenos , Mutación , Nucleótidos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Proto-Oncogénicas p21(ras)/genéticaRESUMEN
Natural killer (NK) cells play a pivotal role in controlling cancer. Multiple extracellular receptors and internal signaling nodes tightly regulate NK activation. Cyclin-dependent kinases of the mediator complex (CDK8 and CDK19) were described as a signaling intermediates in NK cells. Here, we report for the first time the development and use of CDK8/19 inhibitors to suppress phosphorylation of STAT1S727 in NK cells and to augment the production of the cytolytic molecules perforin and granzyme B (GZMB). Functionally, this resulted in enhanced NK-cell-mediated lysis of primary leukemia cells. Treatment with the CDK8/19 inhibitor BI-1347 increased the response rate and survival of mice bearing melanoma and breast cancer xenografts. In addition, CDK8/19 inhibition augmented the antitumoral activity of anti-PD-1 antibody and SMAC mimetic therapy, both agents that promote T-cell-mediated antitumor immunity. Treatment with the SMAC mimetic compound BI-8382 resulted in an increased number of NK cells infiltrating EMT6 tumors. Combination of the CDK8/19 inhibitor BI-1347, which augments the amount of degranulation enzymes, with the SMAC mimetic BI-8382 resulted in increased survival of mice carrying the EMT6 breast cancer model. The observed survival benefit was dependent on an intermittent treatment schedule of BI-1347, suggesting the importance of circumventing a hyporesponsive state of NK cells. These results suggest that CDK8/19 inhibitors can be combined with modulators of the adaptive immune system to inhibit the growth of solid tumors, independent of their activity on cancer cells, but rather through promoting NK-cell function.
Asunto(s)
Neoplasias de la Mama/tratamiento farmacológico , Quinasa 8 Dependiente de Ciclina/antagonistas & inhibidores , Quinasas Ciclina-Dependientes/antagonistas & inhibidores , Células Asesinas Naturales/inmunología , Leucemia Mieloide Aguda/tratamiento farmacológico , Melanoma Experimental/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Animales , Apoptosis , Neoplasias de la Mama/enzimología , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/patología , Proliferación Celular , Citotoxicidad Inmunológica/inmunología , Femenino , Humanos , Células Asesinas Naturales/efectos de los fármacos , Leucemia Mieloide Aguda/enzimología , Leucemia Mieloide Aguda/inmunología , Leucemia Mieloide Aguda/patología , Melanoma Experimental/enzimología , Melanoma Experimental/inmunología , Melanoma Experimental/patología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ratones SCID , Fosforilación , Factor de Transcripción STAT1/metabolismo , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The epidermal growth factor receptor (EGFR), when carrying an activating mutation like del19 or L858R, acts as an oncogenic driver in a subset of lung tumors. While tumor responses to tyrosine kinase inhibitors (TKIs) are accompanied by marked tumor shrinkage, the response is usually not durable. Most patients relapse within two years of therapy often due to acquisition of an additional mutation in EGFR kinase domain that confers resistance to TKIs. Crucially, oncogenic EGFR harboring both resistance mutations, T790M and C797S, can no longer be inhibited by currently approved EGFR TKIs. Here, we describe the discovery of BI-4020, which is a noncovalent, wild-type EGFR sparing, macrocyclic TKI. BI-4020 potently inhibits the above-described EGFR variants and induces tumor regressions in a cross-resistant EGFRdel19â¯T790Mâ¯C797S xenograft model. Key was the identification of a highly selective but moderately potent benzimidazole followed by complete rigidification of the molecule through macrocyclization.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Animales , Antineoplásicos/farmacocinética , Bencimidazoles/química , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Cristalografía por Rayos X , Ciclización , Entropía , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/química , Receptores ErbB/genética , Femenino , Hepatocitos , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Ratones , Ratones Transgénicos , Mutación , Conformación Proteica , Inhibidores de Proteínas Quinasas/farmacocinética , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Phosphoglycerate dehydrogenase (PHGDH) is known to be the rate-limiting enzyme in the serine synthesis pathway in humans. It converts glycolysis-derived 3-phosphoglycerate to 3-phosphopyruvate in a co-factor-dependent oxidation reaction. Herein, we report the discovery of BI-4916, a prodrug of the co-factor nicotinamide adenine dinucleotide (NADH/NAD+)-competitive PHGDH inhibitor BI-4924, which has shown high selectivity against the majority of other dehydrogenase targets. Starting with a fragment-based screening, a subsequent hit optimization using structure-based drug design was conducted to deliver a single-digit nanomolar lead series and to improve potency by 6 orders of magnitude. To this end, an intracellular ester cleavage mechanism of the ester prodrug was utilized to achieve intracellular enrichment of the actual carboxylic acid based drug and thus overcome high cytosolic levels of the competitive cofactors NADH/NAD+.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Indoles/farmacología , Fosfoglicerato-Deshidrogenasa/antagonistas & inhibidores , Serina/antagonistas & inhibidores , Línea Celular Tumoral , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Indoles/síntesis química , Indoles/química , Modelos Moleculares , Estructura Molecular , Fosfoglicerato-Deshidrogenasa/metabolismo , Serina/biosíntesis , Relación Estructura-ActividadRESUMEN
Bromodomain and extra-terminal (BET) protein inhibitors have been reported as treatment options for acute myeloid leukemia (AML) in preclinical models and are currently being evaluated in clinical trials. This work presents a novel potent and selective BET inhibitor (BI 894999), which has recently entered clinical trials (NCT02516553). In preclinical studies, this compound is highly active in AML cell lines, primary patient samples, and xenografts. HEXIM1 is described as an excellent pharmacodynamic biomarker for target engagement in tumors as well as in blood. Mechanistic studies show that BI 894999 targets super-enhancer-regulated oncogenes and other lineage-specific factors, which are involved in the maintenance of the disease state. BI 894999 is active as monotherapy in AML xenografts, and in addition leads to strongly enhanced antitumor effects in combination with CDK9 inhibitors. This treatment combination results in a marked decrease of global p-Ser2 RNA polymerase II levels and leads to rapid induction of apoptosis in vitro and in vivo. Together, these data provide a strong rationale for the clinical evaluation of BI 894999 in AML.
Asunto(s)
Antineoplásicos/administración & dosificación , Elementos de Facilitación Genéticos/efectos de los fármacos , Flavonoides/administración & dosificación , Perfilación de la Expresión Génica/métodos , Leucemia Mieloide Aguda/tratamiento farmacológico , Piperidinas/administración & dosificación , Proteínas/antagonistas & inhibidores , Pirazinas/administración & dosificación , Triazoles/administración & dosificación , Animales , Antineoplásicos/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Quinasa 9 Dependiente de la Ciclina/antagonistas & inhibidores , Regulación hacia Abajo , Sinergismo Farmacológico , Quimioterapia Combinada , Flavonoides/farmacología , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Células HL-60 , Humanos , Leucemia Mieloide Aguda/genética , Ratones , Piperidinas/farmacología , Pirazinas/farmacología , ARN Polimerasa II/metabolismo , Proteínas de Unión al ARN/genética , Factores de Transcripción , Triazoles/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The transcription factor BCL6 is a known driver of oncogenesis in lymphoid malignancies, including diffuse large B cell lymphoma (DLBCL). Disruption of its interaction with transcriptional repressors interferes with the oncogenic effects of BCL6. We used a structure-based drug design to develop highly potent compounds that block this interaction. A subset of these inhibitors also causes rapid ubiquitylation and degradation of BCL6 in cells. These compounds display significantly stronger induction of expression of BCL6-repressed genes and anti-proliferative effects than compounds that merely inhibit co-repressor interactions. This work establishes the BTB domain as a highly druggable structure, paving the way for the use of other members of this protein family as drug targets. The magnitude of effects elicited by this class of BCL6-degrading compounds exceeds that of our equipotent non-degrading inhibitors, suggesting opportunities for the development of BCL6-based lymphoma therapeutics.