ABSTRACT
PURPOSE: Tumors activate protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK, also called EIF2AK3) in response to hypoxia and nutrient deprivation as a stress-mitigation strategy. Here, we tested the hypothesis that inhibiting PERK with HC-5404 enhances the antitumor efficacy of standard-of-care VEGF receptor tyrosine kinase inhibitors (VEGFR-TKI). EXPERIMENTAL DESIGN: HC-5404 was characterized as a potent and selective PERK inhibitor, with favorable in vivo properties. Multiple renal cell carcinoma (RCC) tumor models were then cotreated with both HC-5404 and VEGFR-TKI in vivo, measuring tumor volume across time and evaluating tumor response by protein analysis and IHC. RESULTS: VEGFR-TKI including axitinib, cabozantinib, lenvatinib, and sunitinib induce PERK activation in 786-O RCC xenografts. Cotreatment with HC-5404 inhibited PERK in tumors and significantly increased antitumor effects of VEGFR-TKI across multiple RCC models, resulting in tumor stasis or regression. Analysis of tumor sections revealed that HC-5404 enhanced the antiangiogenic effects of axitinib and lenvatinib by inhibiting both new vasculature and mature tumor blood vessels. Xenografts that progress on axitinib monotherapy remain sensitive to the combination treatment, resulting in â¼20% tumor regression in the combination group. When tested across a panel of 18 RCC patient-derived xenograft (PDX) models, the combination induced greater antitumor effects relative to monotherapies. In this single animal study, nine out of 18 models responded with ≥50% tumor regression from baseline in the combination group. CONCLUSIONS: By disrupting an adaptive stress response evoked by VEGFR-TKI, HC-5404 presents a clinical opportunity to improve the antitumor effects of well-established standard-of-care therapies in RCC.
Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Animals , Humans , Carcinoma, Renal Cell/pathology , Axitinib/pharmacology , Axitinib/therapeutic use , Kidney Neoplasms/pathology , Protein Kinase Inhibitors/therapeutic useABSTRACT
The protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) is one of three endoplasmic reticulum (ER) transmembrane sensors of the unfolded protein response (UPR) responsible for regulating protein synthesis and alleviating ER stress. PERK has been implicated in tumorigenesis, cancer cell survival as well metabolic diseases such as diabetes. The structure-based design and optimization of a novel mandelamide-derived pyrrolopyrimidine series of PERK inhibitors as described herein, resulted in the identification of compound 26, a potent, selective, and orally bioavailable compound suitable for interrogating PERK pathway biology in vitro and in vivo, with pharmacokinetics suitable for once-a-day oral dosing in mice.
ABSTRACT
Herein we report the discovery of 2,4-1H-imidazole carboxamides as novel, biochemically potent, and kinome selective inhibitors of transforming growth factor ß-activated kinase 1 (TAK1). The target was subjected to a DNA-encoded chemical library (DECL) screen. After hit analysis a cluster of compounds was identified, which was based on a central pyrrole-2,4-1H-dicarboxamide scaffold, showing remarkable kinome selectivity. A scaffold-hop to the corresponding imidazole resulted in increased biochemical potency. Next, X-ray crystallography revealed a distinct binding mode compared to other TAK1 inhibitors. A benzylamide was found in a perpendicular orientation with respect to the core hinge-binding imidazole. Additionally, an unusual amide flip was observed in the kinase hinge region. Using structure-based drug design (SBDD), key substitutions at the pyrrolidine amide and the glycine resulted in a significant increase in biochemical potency.
ABSTRACT
The protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) is one of the three endoplasmic reticulum (ER) transmembrane sensors of the unfolded protein response (UPR) that regulates protein synthesis, alleviates cellular ER stress and has been implicated in tumorigenesis and prolonged cancer cell survival. In this study, we report a series of 2-amino-3-amido-5-aryl-pyridines that we have identified as potent, selective, and orally bioavailable PERK inhibitors. Amongst the series studied herein, compound (28) a (R)-2-Amino-5-(4-(2-(3,5-difluorophenyl)-2-hydroxyacetamido)-2-ethylphenyl)-N-isopropylnicotinamide has demonstrated potent biochemical and cellular activity, robust pharmacokinetics and 70% oral bioavailability in mice. Given these data, this compound (28) was studied in the 786-O renal cell carcinoma xenograft model. We observed dose-dependent, statistically significant tumor growth inhibition, supporting the use of this tool compound in additional mechanistic studies.
Subject(s)
Drug Discovery , Pyridines/pharmacology , eIF-2 Kinase/antagonists & inhibitors , Administration, Oral , Biological Availability , Dose-Response Relationship, Drug , Humans , Molecular Structure , Pyridines/administration & dosage , Pyridines/chemistry , Structure-Activity Relationship , eIF-2 Kinase/metabolismABSTRACT
Metastasis is the major cause of death in cancer patients, yet the genetic and epigenetic programs that drive metastasis are poorly understood. Here, we report an epigenetic reprogramming pathway that is required for breast cancer metastasis. Concerted differential DNA methylation is initiated by the activation of the RON receptor tyrosine kinase by its ligand, macrophage stimulating protein (MSP). Through PI3K signaling, RON/MSP promotes expression of the G:T mismatch-specific thymine glycosylase MBD4. RON/MSP and MBD4-dependent aberrant DNA methylation results in the misregulation of a specific set of genes. Knockdown of MBD4 reverses methylation at these specific loci and blocks metastasis. We also show that the MBD4 glycosylase catalytic residue is required for RON/MSP-driven metastasis. Analysis of human breast cancers revealed that this epigenetic program is significantly associated with poor clinical outcome. Furthermore, inhibition of Ron kinase activity with a pharmacological agent blocks metastasis of patient-derived breast tumor grafts in vivo.
Subject(s)
Breast Neoplasms/genetics , DNA Methylation , Endodeoxyribonucleases/metabolism , Epigenesis, Genetic , Gene Expression Regulation, Neoplastic , Receptor Protein-Tyrosine Kinases/metabolism , Animals , Breast Neoplasms/diagnosis , Breast Neoplasms/metabolism , Carcinogenesis/genetics , Endodeoxyribonucleases/genetics , Female , Hepatocyte Growth Factor/metabolism , Humans , MCF-7 Cells , Mammary Neoplasms, Experimental/genetics , Mammary Neoplasms, Experimental/metabolism , Mice , Neoplasm Metastasis , Phosphatidylinositol 3-Kinases/metabolism , Prognosis , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/geneticsABSTRACT
The kinase selectivity and pharmacokinetic optimization of a series of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1 is described. The intersection of insights from molecular modeling, computational prediction of metabolic sites, and in vitro metabolite identification studies resulted in a simple and unique solution to both of these problems. These efforts culminated in the discovery of compound 13a, a potent, relatively selective inhibitor of TAK1 with good pharmacokinetic properties in mice, which was active in an in vivo model of ovarian cancer.
Subject(s)
Enzyme Inhibitors , MAP Kinase Kinase Kinases/antagonists & inhibitors , Pyridines , Amines/chemical synthesis , Amines/chemistry , Amines/pharmacology , Animals , Crystallography, X-Ray , Enzyme Activation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Furans/chemical synthesis , Furans/chemistry , Furans/pharmacology , Humans , Inhibitory Concentration 50 , MAP Kinase Kinase Kinases/metabolism , Mice , Molecular Structure , Neoplasms/drug therapy , Phosphotransferases/chemistry , Phosphotransferases/metabolism , Pyridines/chemical synthesis , Pyridines/pharmacokinetics , Pyridines/pharmacology , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
The discovery and potency optimization of a series of 7-aminofuro[2,3-c]pyridine inhibitors of TAK1 is described. Micromolar hits taken from high-throughput screening were optimized for biochemical and cellular mechanistic potency to ~10nM, as exemplified by compound 12az. Application of structure-based drug design aided by co-crystal structures of TAK1 with inhibitors significantly shortened the number of iterations required for the optimization.
Subject(s)
MAP Kinase Kinase Kinases/antagonists & inhibitors , Pyridines , Amines/chemical synthesis , Amines/chemistry , Amines/pharmacology , Animals , Crystallography, X-Ray , Drug Design , Enzyme Activation/drug effects , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Furans/chemical synthesis , Furans/chemistry , Furans/pharmacology , Humans , Inhibitory Concentration 50 , Mice , Molecular Structure , Neoplasms/drug therapy , Pyridines/chemical synthesis , Pyridines/pharmacokinetics , Pyridines/pharmacology , Structure-Activity Relationship , Xenograft Model Antitumor AssaysABSTRACT
A series of novel 6-aminofuro[3,2-c]pyridines as kinase inhibitors is described, most notably, OSI-296 (6). We discuss our exploration of structure-activity relationships and optimization leading to OSI-296 and disclose its pharmacological activity against cMET and RON in cellular assays. OSI-296 is a potent and selective inhibitor of cMET and RON kinases that shows in vivo efficacy in tumor xenografts models upon oral dosing and is well tolerated.
Subject(s)
Antineoplastic Agents/chemistry , Protein Kinase Inhibitors/chemistry , Proto-Oncogene Proteins c-met/antagonists & inhibitors , Pyridines/chemistry , Receptor Protein-Tyrosine Kinases/antagonists & inhibitors , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cell Survival/drug effects , Female , Half-Life , Humans , Hydrogen-Ion Concentration , Mice , Mice, Nude , Mutation , Neoplasms/drug therapy , Phosphorylation/drug effects , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Proto-Oncogene Proteins c-met/genetics , Proto-Oncogene Proteins c-met/metabolism , Pyridines/pharmacokinetics , Pyridines/therapeutic use , Rats , Rats, Sprague-Dawley , Receptor Protein-Tyrosine Kinases/metabolism , Structure-Activity Relationship , Transplantation, HeterologousABSTRACT
This Letter describes the medicinal chemistry effort towards a series of novel imidazo[1,5-a]pyrazine derived inhibitors of ACK1. Virtual screening led to the discovery of the initial hit, and subsequent exploration of structure-activity relationships and optimization of drug metabolism and pharmacokinetic properties led to the identification of potent, selective and orally bioavailable ACK1 inhibitors.
Subject(s)
Imidazoles/chemistry , Protein Kinase Inhibitors/pharmacology , Protein-Tyrosine Kinases/antagonists & inhibitors , Pyrazines/chemistry , Administration, Oral , Animals , Humans , Imidazoles/pharmacokinetics , Imidazoles/pharmacology , Mice , Protein Kinase Inhibitors/chemical synthesis , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Pyrazines/pharmacokinetics , Pyrazines/pharmacology , Structure-Activity RelationshipABSTRACT
Based on over three decades of pre-clinical data, insulin-like growth factor-1 receptor (IGF-1R) signaling has gained recognition as a promoter of tumorogenesis, driving cell survival and proliferation in multiple human cancers. As a result, IGF-1R has been pursued as a target for cancer treatment. Early pioneering efforts targeting IGF-1R focused on highly selective monoclonal antibodies, with multiple agents advancing to clinical trials. However, despite some initial promising results, recent clinical disclosures have been less encouraging. Moreover, recent studies have revealed that IGF-1R participates in a dynamic and complex signaling network, interacting with additional targets and pathways thereof through various crosstalk and compensatory signaling mechanisms. Such mechanisms of bypass signaling help to shed some light on the decreased effectiveness of selective IGF-1R targeted therapies (e.g. monoclonal antibodies) and suggest that targeting multiple nodes within this signaling network might be necessary to produce a more effective therapeutic response. Additionally, such findings have led to the development of small molecule IGF-1R inhibitors which also co-inhibit additional targets such as insulin receptor and epidermal growth factor receptor. Such findings have helped to guide the design rationale of numerous drug combinations that are currently being evaluated in clinical trials.
ABSTRACT
This letter describes a series of small molecule inhibitors of IGF-1R with unique time-dependent binding kinetics and slow off-rates. Structure-activity and structure-kinetic relationships were elucidated and guided further optimizations within the series, culminating in compound 2. With an IGF-1R dissociative half-life (t 1/2) of >100 h, compound 2 demonstrated significant and extended PD effects in conjunction with tumor growth inhibition in xenograft models at a remarkably low and intermittent dose, which correlated with the observed in vitro slow off-rate properties.
ABSTRACT
IGF-1R has been recognized as a major target in cancer drug discovery due to its strong implications in various stages of tumorigenesis based on accumulated preclinical data. Recent research on compensatory crosstalk between IGF-1R and insulin receptor (IR) signaling pathways suggests that targeting both IGF-1R and IR should result in a more therapeutically beneficial response, than targeting IGF-1R alone (e.g., IGF-1R-specific antibodies). These findings provided biological rationale and opened the door to the discovery of a variety of small-molecule dual IGF-1R and IR inhibitors. In this review we summarize the recent developments in this field, with a focus on binding modes and binding interactions of these inhibitors with IGF-1R and/or IR. Selectivity of these inhibitors has been discussed in this context as well. This is an important area to be discussed since one of the major challenges in kinase inhibitor drug discovery is to build an optimal selectivity profile based on biological rationale.
Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Drug Discovery , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacology , Receptor, IGF Type 1/antagonists & inhibitors , Receptor, Insulin/antagonists & inhibitors , Adenosine Triphosphate/metabolism , Animals , Humans , Models, Molecular , Neoplasms/drug therapy , Neoplasms/enzymology , Receptor, IGF Type 1/metabolism , Receptor, Insulin/metabolism , Small Molecule Libraries/chemistry , Small Molecule Libraries/pharmacologyABSTRACT
The discovery and optimization of a series of imidazo[1,5-a]pyrazine inhibitors of mTOR is described. HTS hits were optimized for potency, selectivity and metabolic stability to provide the orally bioavailable proof of concept compound 4c that demonstrated target inhibition in vivo and concomitant inhibition of tumor growth in an MDA-MB-231 xenograft model.
Subject(s)
Imidazoles/pharmacology , Proteins/antagonists & inhibitors , Pyrazines/pharmacology , Transcription Factors/antagonists & inhibitors , Administration, Oral , Cell Line, Tumor , Humans , Imidazoles/administration & dosage , Mechanistic Target of Rapamycin Complex 1 , Models, Molecular , Multiprotein Complexes , Pyrazines/administration & dosage , TOR Serine-Threonine Kinases , Xenograft Model Antitumor AssaysABSTRACT
Preclinical and emerging clinical evidence suggests that inhibiting insulin-like growth factor 1 receptor (IGF-1R) signaling may offer a promising therapeutic strategy for the treatment of several types of cancer. This Letter describes the medicinal chemistry effort towards a series of 8-amino-imidazo[1,5-a]pyrazine derived inhibitors of IGF-1R which features a substituted quinoline moiety at the C1 position and a cyclohexyl linking moiety at the C3 position. Lead optimization efforts which included the optimization of structure-activity relationships and drug metabolism and pharmacokinetic properties led to the identification of compound 9m, a potent, selective and orally bioavailable inhibitor of IGF-1R with in vivo efficacy in an IGF-driven mouse xenograft model.
Subject(s)
Antineoplastic Agents/chemistry , Benzimidazoles/chemistry , Imidazoles/chemistry , Protein Kinase Inhibitors/chemistry , Pyrazines/chemistry , Receptor, IGF Type 1/antagonists & inhibitors , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/therapeutic use , Benzimidazoles/pharmacokinetics , Benzimidazoles/therapeutic use , Mice , Neoplasms/drug therapy , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/therapeutic use , Pyrazines/pharmacokinetics , Pyrazines/therapeutic use , Receptor, IGF Type 1/metabolism , Structure-Activity Relationship , Transplantation, HeterologousABSTRACT
A complex of RON(M1254T) with AMP-PNP and Mg(2+) reveals a substratelike positioning of Tyr1238 as well as likely catalysis-competent placement of the AMP-PNP and Mg(2+) components and indicates a tendency for cis phosphorylation. The structure shows how the oncogenic mutation may cause the constitutive activation and suggests a mechanistic hypothesis for the autophosphorylation of receptor tyrosine kinases.
Subject(s)
Receptor Protein-Tyrosine Kinases/chemistry , Receptor Protein-Tyrosine Kinases/metabolism , Adenylyl Imidodiphosphate , Phosphorylation , Phosphotransferases , Receptor Protein-Tyrosine Kinases/geneticsABSTRACT
This report describes the investigation of a series of 5,7-disubstituted imidazo[5,1-f][1,2,4]triazine inhibitors of insulin-like growth factor-1 receptor (IGF-1R) and insulin receptor (IR). Structure-activity relationship exploration and optimization leading to the identification, characterization, and pharmacological activity of compound 9b, a potent, selective, well-tolerated, and orally bioavailable dual inhibitor of IGF-1R and IR with in vivo efficacy in tumor xenograft models, is discussed.
ABSTRACT
Imidazo[1,5-a]pyrazines 1 undergo regioselective C3-metalation and C5/C3-dimetalation to afford a range of functionalized derivatives 2a-2g (Table 1 ), and 4a-4d (Table 2 ). Under similar conditions, the C3-methyl derivatives 2a and 5 undergo surprising regioselective C5-deprotonation to afford, after electrophile quench, products 4b and 6a-6p (Table 3 ), results that are rationalized by quantum mechanical calculations. Benzamide 7b, obtained from such metalation chemistry followed by Suzuki cross coupling, undergoes directed remote metalation-cyclization to afford 8, representing the hitherto unknown triazadibenzo[cd,f]azulen-7(6H)-one tricyclic ring system.
Subject(s)
Imidazoles/chemical synthesis , Metals/chemistry , Pyrazines/chemical synthesis , Cyclization , Imidazoles/chemistry , Molecular Structure , Pyrazines/chemistry , Quantum Theory , StereoisomerismABSTRACT
BACKGROUND: The IGF-1 receptor (IGF-1R) has been implicated in the promotion of tumorigenesis, metastasis and resistance to cancer therapies. Therefore, this receptor has become a major focus for the development of anticancer agents. RESULTS: Our lead optimization efforts that blended structure-based design and empirical medicinal chemistry led to the discovery of OSI-906, a novel small-molecule dual IGF-1R/insulin receptor (IR) kinase inhibitor. OSI-906 potently and selectively inhibits autophosphorylation of both human IGF-1R and IR, displays in vitro antiproliferative effects in a variety of tumor cell lines and shows robust in vivo anti-tumor efficacy in an IGF-1R-driven xenograft model when administered orally once daily. CONCLUSION: OSI-906 is a novel, potent, selective and orally bioavailable dual IGF-1R/IR kinase inhibitor with favorable preclinical drug-like properties, which has demonstrated in vivo efficacy in tumor models and is currently in clinical testing.
Subject(s)
Antineoplastic Agents/therapeutic use , Imidazoles/therapeutic use , Neoplasms/drug therapy , Pyrazines/therapeutic use , Receptor, IGF Type 1/antagonists & inhibitors , Receptor, Insulin/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Cell Line , Female , Humans , Imidazoles/chemical synthesis , Imidazoles/chemistry , Imidazoles/metabolism , Mice , Mice, Nude , Microsomes/metabolism , Models, Molecular , Molecular Structure , Protein Conformation , Pyrazines/chemical synthesis , Pyrazines/chemistry , Pyrazines/metabolism , Rats , Rats, Sprague-Dawley , Receptor, IGF Type 1/chemistry , Receptor, Insulin/chemistry , Xenograft Model Antitumor AssaysABSTRACT
A general and efficient synthesis of 5-aryl imidazo[1,5- a]pyrazines by palladium-catalyzed coupling of the corresponding 8-substituted derivatives with aryl halides is described. The scope of this new reaction for the imidazo[1,5- a]pyrazine ring system was explored using three readily available 8-substituted precursors, X = NH2, NMe2, and OMe, as well as 8-aryl derivatives, X = Ar'. On the basis of these results as well as studies using a deuterated derivative, a Heck-like mechanism is proposed for this transformation.