RESUMO
Structure-based design was utilized to optimize 6,6-diaryl substituted dihydropyrone and hydroxylactam to obtain inhibitors of lactate dehydrogenase (LDH) with low nanomolar biochemical and single-digit micromolar cellular potencies. Surprisingly the replacement of a phenyl with a pyridyl moiety in the chemical structure revealed a new binding mode for the inhibitors with subtle conformational change of the LDHA active site. This led to the identification of a potent, cell-active hydroxylactam inhibitor exhibiting an in vivo pharmacokinetic profile suitable for mouse tumor xenograft study.
Assuntos
Inibidores Enzimáticos/farmacologia , L-Lactato Desidrogenase/antagonistas & inibidores , Lactamas/farmacologia , Animais , Linhagem Celular , Cães , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Humanos , L-Lactato Desidrogenase/metabolismo , Lactamas/química , Camundongos , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Chimeric molecules which effect intracellular degradation of target proteins via E3 ligase-mediated ubiquitination (e.g., PROTACs) are currently of high interest in medicinal chemistry. However, these entities are relatively large compounds that often possess molecular characteristics which may compromise oral bioavailability, solubility, and/or in vivo pharmacokinetic properties. Accordingly, we explored whether conjugation of chimeric degraders to monoclonal antibodies using technologies originally developed for cytotoxic payloads might provide alternate delivery options for these novel agents. In this report we describe the construction of several degrader-antibody conjugates comprised of two distinct ERα-targeting degrader entities and three independent ADC linker modalities. We subsequently demonstrate the antigen-dependent delivery to MCF7-neo/HER2 cells of the degrader payloads that are incorporated into these conjugates. We also provide evidence for efficient intracellular degrader release from one of the employed linkers. In addition, preliminary data are described which suggest that reasonably favorable in vivo stability properties are associated with the linkers utilized to construct the degrader conjugates.
Assuntos
Anticorpos Monoclonais/imunologia , Portadores de Fármacos/química , Receptor alfa de Estrogênio/imunologia , Anticorpos Monoclonais/química , Antineoplásicos/química , Antineoplásicos/imunologia , Antineoplásicos/farmacologia , Desenho de Fármacos , Receptor alfa de Estrogênio/metabolismo , Humanos , Imunoconjugados/química , Imunoconjugados/imunologia , Imunoconjugados/farmacologia , Células MCF-7 , Proteólise/efeitos dos fármacos , Receptor ErbB-2/metabolismoRESUMO
This work discloses the first examples of antibody-drug conjugates (ADCs) that are constructed from linker-drugs bearing dimeric seco-CBI payloads (duocarmycin analogs). Several homogeneous, CD22-targeting THIOMAB antibody-drug conjugates (TDCs) containing the dimeric seco-CBI entities are shown to be highly efficacious in the WSU-DLCL2 and BJAB mouse xenograft models. Surprisingly, the seco-CBI-containing conjugates are also observed to undergo significant biotransformation in vivo in mice, rats, and monkeys and thereby form 1:1 adducts with the Alpha-1-Microglobulin (A1M) plasma protein from these species. Variation of both the payload mAb attachment site and length of the linker-drug is shown to alter the rates of adduct formation. Subsequent experiments demonstrated that adduct formation attenuates the in vitro antiproliferation activity of the affected seco-CBI-dimer TDCs, but does not significantly impact the in vivo efficacy of the conjugates. In vitro assays employing phosphatase-treated whole blood suggest that A1M adduct formation is likely to occur if the seco-CBI-dimer TDCs are administered to humans. Importantly, protein adduct formation leads to the underestimation of total antibody (Tab) concentrations using an ELISA assay but does not affect Tab values determined via an orthogonal LC-MS/MS method. Several recommendations regarding bioanalysis of future in vivo studies involving related seco-CBI-containing ADCs are provided based on these collective findings.
Assuntos
alfa-Globulinas/química , Antineoplásicos/farmacologia , Imunoconjugados/farmacologia , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dimerização , Haplorrinos , Humanos , Imunoconjugados/química , Camundongos , Ratos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Duocarmycins [including cyclopropyl pyrroloindole (CPI) or cyclopropyl benzoindole (CBI)] are a class of DNA minor-groove alkylators and seco-CPI/CBIs are synthetic pro-forms that can spirocyclize to CPI/CBI. Bis-CPI/CBIs are potential drug candidates because of their enhanced cytotoxicity from DNA crosslinking, but it is difficult to analyze them for structure-activity correlation because of their DNA reactivity. To study their DNA alkylation, neutral thermal hydrolysis has been frequently applied to process depurination. However, unwanted side reactions under this condition have been reported, which could lead to poor correlation of DNA alkylation data with efficacy results, especially for bis-CPI/CBIs. In this study, an acidic depurination method was developed and applied for analysis of DNA alkylation and shown to be an easier and milder method than the traditional neutral thermal hydrolysis. DNA alkylation and stability of three bis-seco-CBIs were characterized in comparison with two mono-seco-CPIs. The results suggested that: 1) The acidic depurination method was capable of capturing a more representative population, sometimes a different population, of DNA adducts as they existed on DNA compared with the heat depurination method. 2) Di-adenine adducts were captured as expected for the CBI dimers, although the major type of adduct was still mono-adenine adducts. 3) The rate of DNA alkylation, DNA adduct profile, and relative amounts of di-adduct versus mono-adduct were significantly affected by the size, and possibly lipophilicity, of the nonalkylating part of the molecules. 4) Spirocyclization and amide hydrolysis represented two major pathways of degradation. Overall, by applying acidic depurination analyses, this study has illustrated DNA adduct characteristics of novel bis-seco-CBIs with dominating mono-alkylation and provides an alternative method for evaluating DNA minor-groove alkylators. These findings provide an effective analytical tool to evaluate DNA alkylators and to study the DNA alkylation that is a disposition mechanism of these compounds.
Assuntos
Alquilação/fisiologia , Antineoplásicos Alquilantes/metabolismo , DNA/metabolismo , Duocarmicinas/metabolismo , Adenina/metabolismo , Alquilantes/metabolismo , Adutos de DNA/metabolismoRESUMO
THIOMAB antibody technology utilizes cysteine residues engineered onto an antibody to allow for site-specific conjugation. The technology has enabled the exploration of different attachment sites on the antibody in combination with small molecules, peptides, or proteins to yield antibody conjugates with unique properties. As reported previously ( Shen , B. Q. , et al. ( 2012 ) Nat. Biotechnol. 30 , 184 - 189 ; Pillow , T. H. , et al. ( 2017 ) Chem. Sci. 8 , 366 - 370 ), the specific location of the site of conjugation on an antibody can impact the stability of the linkage to the engineered cysteine for both thio-succinimide and disulfide bonds. High stability of the linkage is usually desired to maximize the delivery of the cargo to the intended target. In the current study, cysteines were individually substituted into every position of the anti-HER2 antibody (trastuzumab), and the stabilities of drug conjugations at those sites were evaluated. We screened a total of 648 THIOMAB antibody-drug conjugates, each generated from a trastuzamab prepared by sequentially mutating non-cysteine amino acids in the light and heavy chains to cysteine. Each THIOMAB antibody variant was conjugated to either maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl-monomethyl auristatin E (MC-vc-PAB-MMAE) or pyridyl disulfide monomethyl auristatin E (PDS-MMAE) using a high-throughput, on-bead conjugation and purification method. Greater than 50% of the THIOMAB antibody variants were successfully conjugated to both MMAE derivatives with a drug to antibody ratio (DAR) of >0.5 and <50% aggregation. The relative in vitro plasma stabilities for approximately 750 conjugates were assessed using enzyme-linked immunosorbent assays, and stable sites were confirmed with affinity-capture LC/MS-based detection methods. Highly stable conjugation sites for the two types of MMAE derivatives were identified on both the heavy and light chains. Although the stabilities of maleimide conjugates were shown to be greater than those of the disulfide conjugates, many sites were identified that were stable for both. Furthermore, in vitro stabilities of selected stable sites translated across different cytotoxic payloads and different target antibodies as well as to in vivo stability.
Assuntos
Antineoplásicos Imunológicos/química , Cisteína/química , Dissulfetos/química , Imunoconjugados/química , Maleimidas/química , Trastuzumab/química , Animais , Antineoplásicos Imunológicos/sangue , Cisteína/sangue , Cisteína/genética , Dissulfetos/sangue , Estabilidade de Medicamentos , Ensaios de Triagem em Larga Escala , Humanos , Imunoconjugados/sangue , Maleimidas/sangue , Modelos Moleculares , Mutagênese Sítio-Dirigida , Oligopeptídeos/sangue , Oligopeptídeos/química , Agregados Proteicos , Estabilidade Proteica , Ratos , Trastuzumab/sangue , Trastuzumab/genéticaRESUMO
The valine-citrulline (Val-Cit) dipeptide and p-aminobenzyl (PAB) spacer have been commonly used as a cleavable self-immolating linker in ADC design including in the clinically approved ADC, brentuximab vedotin (Adcetris). When the same linker was used to connect to the phenol of the cyclopropabenzindolone (CBI) (P1), the resulting ADC1 showed loss of potency in CD22 target-expressing cancer cell lines (e.g., BJAB, WSU-DLCL2). In comparison, the conjugate (ADC2) of a cyclopropapyrroloindolone (CPI) (P2) was potent despite the two corresponding free drugs having similar picomolar cell-killing activity. Although the corresponding spirocyclization products of P1 and P2, responsible for DNA alkylation, are a prominent component in buffer, the linker immolation was slow when the PAB was connected as an ether (PABE) to the phenol in P1 compared to that in P2. Additional immolation studies with two other PABE-linked substituted phenol compounds showed that electron-withdrawing groups accelerated the immolation to release an acidic phenol-containing payload (to delocalize the negative charge on the anticipated anionic phenol oxygen during immolation). In contrast, efficient immolation of LD4 did not result in an active ADC4 because the payload (P4) had a low potency to kill cells. In addition, nonimmolation of LD5 did not affect the cell-killing potency of its ADC5 since immolation is not required for DNA alkylation by the center-linked pyrrolobenzodiazepine. Therefore, careful evaluation needs to be conducted when the Val-Cit-PAB linker is used to connect antibodies to a phenol-containing drug as the linker immolation, as well as payload potency and stability, affects the cell-killing activity of an ADC.
Assuntos
Sobrevivência Celular/efeitos dos fármacos , Imunoconjugados/química , Imunoconjugados/farmacologia , Fenol/química , Fenol/farmacologia , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacologia , Brentuximab Vedotin , Linhagem Celular Tumoral , Ciclopropanos/química , Ciclopropanos/farmacologia , Humanos , Neoplasias/tratamento farmacológicoRESUMO
Metabolic reprogramming in tumors represents a potential therapeutic target. Herein we used shRNA depletion and a novel lactate dehydrogenase (LDHA) inhibitor, GNE-140, to probe the role of LDHA in tumor growth in vitro and in vivo. In MIA PaCa-2 human pancreatic cells, LDHA inhibition rapidly affected global metabolism, although cell death only occurred after 2 d of continuous LDHA inhibition. Pancreatic cell lines that utilize oxidative phosphorylation (OXPHOS) rather than glycolysis were inherently resistant to GNE-140, but could be resensitized to GNE-140 with the OXPHOS inhibitor phenformin. Acquired resistance to GNE-140 was driven by activation of the AMPK-mTOR-S6K signaling pathway, which led to increased OXPHOS, and inhibitors targeting this pathway could prevent resistance. Thus, combining an LDHA inhibitor with compounds targeting the mitochondrial or AMPK-S6K signaling axis may not only broaden the clinical utility of LDHA inhibitors beyond glycolytically dependent tumors but also reduce the emergence of resistance to LDHA inhibition.
Assuntos
Plasticidade Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , L-Lactato Desidrogenase/antagonistas & inibidores , Piridonas/farmacologia , Tiofenos/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Humanos , L-Lactato Desidrogenase/metabolismo , Modelos Moleculares , Estrutura Molecular , Piridonas/química , Relação Estrutura-Atividade , Tiofenos/químicaRESUMO
The incorporation of cysteines into antibodies by mutagenesis allows for the direct conjugation of small molecules to specific sites on the antibody via disulfide bonds. The stability of the disulfide bond linkage between the small molecule and the antibody is highly dependent on the location of the engineered cysteine in either the heavy chain (HC) or the light chain (LC) of the antibody. Here, we explore the basis for this site-dependent stability. We evaluated the in vivo efficacy and pharmacokinetics of five different cysteine mutants of trastuzumab conjugated to a pyrrolobenzodiazepine (PBD) via disulfide bonds. A significant correlation was observed between disulfide stability and efficacy for the conjugates. We hypothesized that the observed site-dependent stability of the disulfide-linked conjugates could be due to differences in the attachment site cysteine thiol pKa. We measured the cysteine thiol pKa using isothermal titration calorimetry (ITC) and found that the variants with the highest thiol pKa (LC K149C and HC A140C) were found to yield the conjugates with the greatest in vivo stability. Guided by homology modeling, we identified several mutations adjacent to LC K149C that reduced the cysteine thiol pKa and, thus, decreased the in vivo stability of the disulfide-linked PBD conjugated to LC K149C. We also present results suggesting that the high thiol pKa of LC K149C is responsible for the sustained circulation stability of LC K149C TDCs utilizing a maleimide-based linker. Taken together, our results provide evidence that the site-dependent stability of cys-engineered antibody-drug conjugates may be explained by interactions between the engineered cysteine and the local protein environment that serves to modulate the side-chain thiol pKa. The influence of cysteine thiol pKa on stability and efficacy offers a new parameter for the optimization of ADCs that utilize cysteine engineering.
Assuntos
Cisteína/química , Imunoconjugados/química , Benzodiazepinas/química , Estabilidade de Medicamentos , Imunoconjugados/genética , Maleimidas/química , Modelos Moleculares , Mutação , Conformação Proteica , Pirróis/químicaRESUMO
Optimization of 5-(2,6-dichlorophenyl)-3-hydroxy-2-mercaptocyclohex-2-enone using structure-based design strategies resulted in inhibitors with considerable improvement in biochemical potency against human lactate dehydrogenase A (LDHA). These potent inhibitors were typically selective for LDHA over LDHB isoform (410 fold) and other structurally related malate dehydrogenases, MDH1 and MDH2 (>500 fold). An X-ray crystal structure of enzymatically most potent molecule bound to LDHA revealed two additional interactions associated with enhanced biochemical potency.
Assuntos
Inibidores Enzimáticos/síntese química , L-Lactato Desidrogenase/antagonistas & inibidores , Animais , Cristalografia por Raios X , Cães , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , L-Lactato Desidrogenase/metabolismo , Células Madin Darby de Rim CaninoRESUMO
A series of 3,6-disubstituted dihydropyrones were identified as inhibitors of human lactate dehydrogenase (LDH)-A. Structure activity relationships were explored and a series of 6,6-spiro analogs led to improvements in LDHA potency (IC50 <350 nM). An X-ray crystal structure of an improved compound bound to human LDHA was obtained and it illustrated additional opportunities to enhance the potency of these compounds, resulting in the identification of 51 (IC50=30 nM).
Assuntos
Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , L-Lactato Desidrogenase/antagonistas & inibidores , Pironas/síntese química , Pironas/farmacologia , Sítios de Ligação , Cristalografia por Raios X , Humanos , L-Lactato Desidrogenase/metabolismo , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
A novel class of 3-hydroxy-2-mercaptocyclohex-2-enone-containing inhibitors of human lactate dehydrogenase (LDH) was identified through a high-throughput screening approach. Biochemical and surface plasmon resonance experiments performed with a screening hit (LDHA IC50=1.7 µM) indicated that the compound specifically associated with human LDHA in a manner that required simultaneous binding of the NADH co-factor. Structural variation of this screening hit resulted in significant improvements in LDHA biochemical inhibition activity (best IC50=0.18 µM). Two crystal structures of optimized compounds bound to human LDHA were obtained and explained many of the observed structure-activity relationships. In addition, an optimized inhibitor exhibited good pharmacokinetic properties after oral administration to rats (F=45%).
Assuntos
Cicloexanonas/farmacologia , Inibidores Enzimáticos/farmacologia , L-Lactato Desidrogenase/antagonistas & inibidores , Compostos de Sulfidrila/farmacologia , Administração Oral , Animais , Cicloexanonas/administração & dosagem , Cicloexanonas/química , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/química , Ensaios de Triagem em Larga Escala , Humanos , L-Lactato Desidrogenase/metabolismo , Modelos Moleculares , Estrutura Molecular , Ratos , Relação Estrutura-Atividade , Compostos de Sulfidrila/administração & dosagem , Compostos de Sulfidrila/químicaRESUMO
Oncogenic KRAS mutations were identified decades ago, yet the selective inhibition of specific KRAS mutant proteins represents an ongoing challenge. Recent progress has been made in targeting certain P-loop mutant proteins, in particular KRAS G12C, for which the covalent inhibition of the GDP state via the Switch II pocket is now a clinically validated strategy. Inhibition of other KRAS mutant proteins such as KRAS G13D, on the other hand, still requires clinical validation. The remoteness of the D13 residue relative to the Switch II pocket in combination with the solvent exposure and conformational flexibility of the D13 side chain, as well as the difficulties of targeting carboxylate residues covalently, renders this specific protein particularly challenging to target selectively. In this report, we describe the design and evaluation of potent and KRAS G13D-selective reversible inhibitors. Subnanomolar binding to the GDP state Switch II pocket and biochemical selectivity over WT KRAS are achieved by leveraging a salt bridge with D13.
RESUMO
Approved antibody-drug conjugates (ADCs) for HER2-positive breast cancer include trastuzumab emtansine and trastuzumab deruxtecan. To develop a differentiated HER2 ADC, we chose an antibody that does not compete with trastuzumab or pertuzumab for binding, conjugated to a reduced potency PBD (pyrrolobenzodiazepine) dimer payload. PBDs are potent cytotoxic agents that alkylate and cross-link DNA. In our study, the PBD dimer is modified to alkylate, but not cross-link DNA. This HER2 ADC, DHES0815A, demonstrates in vivo efficacy in models of HER2-positive and HER2-low cancers and is well-tolerated in cynomolgus monkey safety studies. Mechanisms of action include induction of DNA damage and apoptosis, activity in non-dividing cells, and bystander activity. A dose-escalation study (ClinicalTrials.gov: NCT03451162) in patients with HER2-positive metastatic breast cancer, with the primary objective of evaluating the safety and tolerability of DHES0815A and secondary objectives of characterizing the pharmacokinetics, objective response rate, duration of response, and formation of anti-DHES0815A antibodies, is reported herein. Despite early signs of anti-tumor activity, patients at higher doses develop persistent, non-resolvable dermal, ocular, and pulmonary toxicities, which led to early termination of the phase 1 trial.
Assuntos
Anticorpos Monoclonais Humanizados , Antineoplásicos , Benzodiazepinas , Neoplasias da Mama , Imunoconjugados , Humanos , Animais , Feminino , Neoplasias da Mama/genética , Macaca fascicularis/genética , Receptor ErbB-2/metabolismo , Trastuzumab/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Imunoconjugados/farmacologia , Imunoconjugados/uso terapêutico , DNARESUMO
A 2-amino-5-aryl-pyrazine was identified as an inhibitor of human lactate dehydrogenase A (LDHA) via a biochemical screening campaign. Biochemical and biophysical experiments demonstrated that the compound specifically interacted with human LDHA. Structural variation of the screening hit resulted in improvements in LDHA biochemical inhibition and pharmacokinetic properties. A crystal structure of an improved compound bound to human LDHA was also obtained and it explained many of the observed structure-activity relationships.
Assuntos
Inibidores Enzimáticos/química , L-Lactato Desidrogenase/antagonistas & inibidores , Pirazinas/química , Animais , Sítios de Ligação , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacocinética , Meia-Vida , Humanos , L-Lactato Desidrogenase/metabolismo , Masculino , Microssomos Hepáticos/metabolismo , Estrutura Terciária de Proteína , Pirazinas/síntese química , Pirazinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Substructural class effects surrounding replacement of a 'cis' N-methyl aniline amide within potent and selective thienobenzoxepin PI3-kinase inhibitors are disclosed. While a simple aryl to alkyl switch was not tolerated due to differences in preferred amide conformation, heterocyclic amide isosteres with maintained aryl substitution improved potency and metabolic stability at the cost of physical properties. These gains in potency allowed lipophilic deconstruction of the arene to simple branched alkyl substituents. As such, overall lipophilicity-neutral, MW decreases were realized relative to the aniline amide series. The improved properties for lead compound 21 resulted in high permeability, solubility and bioavailability.
Assuntos
Benzoxepinas/síntese química , Inibidores Enzimáticos/síntese química , Inibidores de Fosfoinositídeo-3 Quinase , Amidas/síntese química , Amidas/química , Amidas/farmacologia , Benzotiazóis/química , Benzoxepinas/química , Benzoxepinas/farmacologia , Sítios de Ligação , Cristalografia por Raios X , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Modelos Moleculares , Tiofenos/síntese química , Tiofenos/química , Tiofenos/farmacologiaRESUMO
In an effort to identify potent and isoform selective inhibitors of PI3Kδ, GNE-293 (34) was identified. Inhibitor 2 was found to induce micronuclei formation in both the MNT and HCA in vitro assays. Compounds testing negative for genotoxicity were successfully identified through modifications of the 2-benzimidazole substituent and the methylene moiety to disrupt planarity. A variety of heteroatom linkers were explored to examine their effect on potency and isoform selectivity by restricting torsional angles to favor ligand interactions with PI3Kδ's Trp760. These modifications also resulted in an improved in vivo pharmacokinetic profile.
Assuntos
Óxidos S-Cíclicos/química , Óxidos S-Cíclicos/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Purinas/química , Purinas/farmacologia , Animais , Linhagem Celular , Cães , Humanos , Simulação de Acoplamento Molecular , Testes de Mutagenicidade , Fosfatidilinositol 3-Quinases/metabolismo , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/toxicidade , Ratos , Relação Estrutura-AtividadeRESUMO
A novel 2-thio-6-oxo-1,6-dihydropyrimidine-containing inhibitor of human lactate dehydrogenase (LDH) was identified by high-throughput screening (IC50=8.1 µM). Biochemical, surface plasmon resonance, and saturation transfer difference NMR experiments indicated that the compound specifically associated with human LDHA in a manner that required simultaneous binding of the NADH co-factor. Structural variation of the screening hit resulted in significant improvements in LDHA biochemical inhibition activity (best IC50=0.48 µM). A crystal structure of an optimized compound bound to human LDHA was obtained and explained many of the observed structure-activity relationships.
Assuntos
Inibidores Enzimáticos/química , L-Lactato Desidrogenase/antagonistas & inibidores , Pirimidinas/química , Sítios de Ligação , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Humanos , Ligação de Hidrogênio , L-Lactato Desidrogenase/metabolismo , Espectroscopia de Ressonância Magnética , NAD/metabolismo , Ligação Proteica , Estrutura Terciária de Proteína , Pirimidinas/síntese química , Pirimidinas/metabolismo , Relação Estrutura-Atividade , Ressonância de Plasmônio de SuperfícieRESUMO
A series of suitable five-membered heterocyclic alternatives to thiophenes within a thienobenzoxepin class of PI3-kinase (PI3K) inhibitors was discovered. Specific thiazolobenzoxepin 8-substitution was identified that increased selectivity over PI3Kß. PI3Kß-sparing compound 27 (PI3Kß Ki,app/PI3Kα Ki,app=57) demonstrated dose-dependent knockdown of pAKT, pPRAS40 and pS6RP in vivo as well as differential effects in an in vitro proliferation cell line screen compared to pan PI3K inhibitor GDC-0941. A new structure-based hypothesis for reducing inhibition of the PI3K ß isoform while maintaining activity against α, δ and γ isoforms is presented.
Assuntos
Benzoxepinas/química , Inibidores Enzimáticos/química , Inibidores de Fosfoinositídeo-3 Quinase , Tiazóis/química , Benzoxepinas/síntese química , Benzoxepinas/farmacologia , Sítios de Ligação , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Humanos , Células MCF-7 , Simulação de Acoplamento Molecular , Fosfatidilinositol 3-Quinase/metabolismo , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-akt/metabolismo , Relação Estrutura-AtividadeRESUMO
A potent inhibitor of PI3Kδ that is ≥ 200 fold selective for the remaining three Class I PI3K isoforms and additional kinases is described. The hypothesis for selectivity is illustrated through structure activity relationships and crystal structures of compounds bound to a K802T mutant of PI3Kγ. Pharmacokinetic data in rats and mice support the use of 3 as a useful tool compound to use for in vivo studies.
Assuntos
Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/química , Triptofano/química , Animais , Sítios de Ligação , Simulação por Computador , Feminino , Injeções Intravenosas , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mutação , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Estrutura Terciária de Proteína , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Hematopoietic progenitor kinase 1 (HPK1) is implicated as a negative regulator of T-cell receptor-induced T-cell activation. Studies using HPK1 kinase-dead knock-in animals have demonstrated the loss of HPK1 kinase activity resulted in an increase in T-cell function and tumor growth inhibition in glioma models. Herein, we describe the discovery of a series of small molecule inhibitors of HPK1. Using a structure-based drug design approach, the kinase selectivity of the molecules was significantly improved by inducing and stabilizing an unusual P-loop folded binding mode. The metabolic liabilities of the initial 7-azaindole high-throughput screening hit were mitigated by addressing a key metabolic soft spot along with physicochemical property-based optimization. The resulting spiro-azaindoline HPK1 inhibitors demonstrated improved in vitro ADME properties and the ability to induce cytokine production in primary human T-cells.