RESUMO
More than 50% of human tumors display hyperactivation of the serine/threonine kinase AKT. Despite evidence of clinical efficacy, the therapeutic window of the current generation of AKT inhibitors could be improved. Here, we report the development of a second-generation AKT degrader, INY-05-040, which outperformed catalytic AKT inhibition with respect to cellular suppression of AKT-dependent phenotypes in breast cancer cell lines. A growth inhibition screen with 288 cancer cell lines confirmed that INY-05-040 had a substantially higher potency than our first-generation AKT degrader (INY-03-041), with both compounds outperforming catalytic AKT inhibition by GDC-0068. Using multiomic profiling and causal network integration in breast cancer cells, we demonstrated that the enhanced efficacy of INY-05-040 was associated with sustained suppression of AKT signaling, which was followed by induction of the stress mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK). Further integration of growth inhibition assays with publicly available transcriptomic, proteomic, and reverse phase protein array (RPPA) measurements established low basal JNK signaling as a biomarker for breast cancer sensitivity to AKT degradation. Together, our study presents a framework for mapping the network-wide signaling effects of therapeutically relevant compounds and identifies INY-05-040 as a potent pharmacological suppressor of AKT signaling.
Assuntos
Neoplasias da Mama , Proteínas Quinases Ativadas por Mitógeno , Humanos , Feminino , Proteínas Proto-Oncogênicas c-akt/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Apoptose , Mitógenos , Multiômica , Proteômica , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno , Proteínas Quinases JNK Ativadas por MitógenoRESUMO
PURPOSE: We evaluated the properties and activity of AZD9574, a blood-brain barrier (BBB) penetrant selective inhibitor of PARP1, and assessed its efficacy and safety alone and in combination with temozolomide (TMZ) in preclinical models. EXPERIMENTAL DESIGN: AZD9574 was interrogated in vitro for selectivity, PARylation inhibition, PARP-DNA trapping, the ability to cross the BBB, and the potential to inhibit cancer cell proliferation. In vivo efficacy was determined using subcutaneous as well as intracranial mouse xenograft models. Mouse, rat, and monkey were used to assess AZD9574 BBB penetration and rat models were used to evaluate potential hematotoxicity for AZD9574 monotherapy and the TMZ combination. RESULTS: AZD9574 demonstrated PARP1-selectivity in fluorescence anisotropy, PARylation, and PARP-DNA trapping assays and in vivo experiments demonstrated BBB penetration. AZD9574 showed potent single agent efficacy in preclinical models with homologous recombination repair deficiency in vitro and in vivo. In an O6-methylguanine-DNA methyltransferase (MGMT)-methylated orthotopic glioma model, AZD9574 in combination with TMZ was superior in extending the survival of tumor-bearing mice compared with TMZ alone. CONCLUSIONS: The combination of three key features-PARP1 selectivity, PARP1 trapping profile, and high central nervous system penetration in a single molecule-supports the development of AZD9574 as the best-in-class PARP inhibitor for the treatment of primary and secondary brain tumors. As documented by in vitro and in vivo studies, AZD9574 shows robust anticancer efficacy as a single agent as well as in combination with TMZ. AZD9574 is currently in a phase I trial (NCT05417594). See related commentary by Lynce and Lin, p. 1217.
Assuntos
Neoplasias Encefálicas , Glioma , Animais , Humanos , Camundongos , Ratos , Antineoplásicos Alquilantes/farmacologia , Barreira Hematoencefálica/metabolismo , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , DNA , Glioma/tratamento farmacológico , Glioma/patologia , O(6)-Metilguanina-DNA Metiltransferase/genética , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Temozolomida/farmacologia , Temozolomida/uso terapêutico , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The structure-based design of small-molecule inhibitors targeting protein-protein interactions (PPIs) remains a huge challenge as the drug must bind typically wide and shallow protein sites. A PPI target of high interest for hematological cancer therapy is myeloid cell leukemia 1 (Mcl-1), a prosurvival guardian protein from the Bcl-2 family. Despite being previously considered undruggable, seven small-molecule Mcl-1 inhibitors have recently entered clinical trials. Here, we report the crystal structure of the clinical-stage inhibitor AMG-176 bound to Mcl-1 and analyze its interaction along with clinical inhibitors AZD5991 and S64315. Our X-ray data reveal high plasticity of Mcl-1 and a remarkable ligand-induced pocket deepening. Nuclear Magnetic Resonance (NMR)-based free ligand conformer analysis demonstrates that such unprecedented induced fit is uniquely achieved by designing highly rigid inhibitors, preorganized in their bioactive conformation. By elucidating key chemistry design principles, this work provides a roadmap for targeting the largely untapped PPI class more successfully.
Assuntos
Apoptose , Naftalenos , Modelos Moleculares , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , LigantesRESUMO
Recent mechanistic studies of dual photoredox/Ni-catalyzed, light-driven cross-coupling reactions have found that the photocatalyst (PC) operates through either reductive quenching or energy transfer cycles. To date, reports invoking oxidative quenching cycles are comparatively rare and direct observation of such a quenching event has not been reported. However, when PCs with highly reducing excited states are used (e.g., Ir(ppy)3), photoreduction of Ni(II) to Ni(I) is thermodynamically feasible. Recently, a unified reaction system using Ir(ppy)3 was developed for forming C-O, C-N, and C-S bonds under the same conditions, a prospect that is challenging with PCs that can photooxidize these nucleophiles. Herein, in a detailed mechanistic study of this system, we observe oxidative quenching of the PC (Ir(ppy)3 or a phenoxazine) via nanosecond transient absorption spectroscopy. Speciation studies support that a mixture of Ni-bipyridine complexes forms under the reaction conditions, and the rate constant for photoreduction increases when more than one ligand is bound. Oxidative addition of an aryl iodide was observed indirectly via oxidation of the resulting iodide by Ir(IV)(ppy)3. Intriguingly, the persistence of the Ir(IV)/Ni(I) ion pair formed in the oxidative quenching step was found to be necessary to simulate the observed kinetics. Both bromide and iodide anions were found to reduce the oxidized form of the PC back to its neutral state. These mechanistic insights inspired the addition of a chloride salt additive, which was found to alter Ni speciation, leading to a 36-fold increase in the initial turnover frequency, enabling the coupling of aryl chlorides.
RESUMO
PURPOSE: We hypothesized that inhibition and trapping of PARP1 alone would be sufficient to achieve antitumor activity. In particular, we aimed to achieve selectivity over PARP2, which has been shown to play a role in the survival of hematopoietic/stem progenitor cells in animal models. We developed AZD5305 with the aim of achieving improved clinical efficacy and wider therapeutic window. This next-generation PARP inhibitor (PARPi) could provide a paradigm shift in clinical outcomes achieved by first-generation PARPi, particularly in combination. EXPERIMENTAL DESIGN: AZD5305 was tested in vitro for PARylation inhibition, PARP-DNA trapping, and antiproliferative abilities. In vivo efficacy was determined in mouse xenograft and PDX models. The potential for hematologic toxicity was evaluated in rat models, as monotherapy and combination. RESULTS: AZD5305 is a highly potent and selective inhibitor of PARP1 with 500-fold selectivity for PARP1 over PARP2. AZD5305 inhibits growth in cells with deficiencies in DNA repair, with minimal/no effects in other cells. Unlike first-generation PARPi, AZD5305 has minimal effects on hematologic parameters in a rat pre-clinical model at predicted clinically efficacious exposures. Animal models treated with AZD5305 at doses ≥0.1 mg/kg once daily achieved greater depth of tumor regression compared to olaparib 100 mg/kg once daily, and longer duration of response. CONCLUSIONS: AZD5305 potently and selectively inhibits PARP1 resulting in excellent antiproliferative activity and unprecedented selectivity for DNA repair deficient versus proficient cells. These data confirm the hypothesis that targeting only PARP1 can retain the therapeutic benefit of nonselective PARPi, while reducing potential for hematotoxicity. AZD5305 is currently in phase I trials (NCT04644068).
Assuntos
Antineoplásicos , Inibidores de Poli(ADP-Ribose) Polimerases , Humanos , Camundongos , Ratos , Animais , Linhagem Celular Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto , Ftalazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1 , Antineoplásicos/farmacologia , Reparo do DNARESUMO
While trifluoromethylthiolation of aryl halides has been extensively explored, the current methods require complex and/or air-sensitive catalysts. Reported here is a method employing a bench-stable Ni(II) salt and an iridium photocatalyst that can mediate the trifluoromethylthiolation of a wide range of electronically diverse aryl and heteroaryl iodides, likely via a Ni(I)/Ni(III) catalytic cycle. The reaction has broad functional group tolerance and potential for application in medicinal chemistry, as demonstrated by a late-stage functionalization approach to access (racemic)-Monepantel.
Assuntos
Iodetos , Níquel , Catálise , IrídioRESUMO
Poly-ADP-ribose-polymerase (PARP) inhibitors have achieved regulatory approval in oncology for homologous recombination repair deficient tumors including BRCA mutation. However, some have failed in combination with first-line chemotherapies, usually due to overlapping hematological toxicities. Currently approved PARP inhibitors lack selectivity for PARP1 over PARP2 and some other 16 PARP family members, and we hypothesized that this could contribute to toxicity. Recent literature has demonstrated that PARP1 inhibition and PARP1-DNA trapping are key for driving efficacy in a BRCA mutant background. Herein, we describe the structure- and property-based design of 25 (AZD5305), a potent and selective PARP1 inhibitor and PARP1-DNA trapper with excellent in vivo efficacy in a BRCA mutant HBCx-17 PDX model. Compound 25 is highly selective for PARP1 over other PARP family members, with good secondary pharmacology and physicochemical properties and excellent pharmacokinetics in preclinical species, with reduced effects on human bone marrow progenitor cells in vitro.
Assuntos
DNA , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases , Poli(ADP-Ribose) Polimerases , Humanos , Cristalografia por Raios X , DNA/química , Poli(ADP-Ribose) Polimerase-1/antagonistas & inibidores , Inibidores de Poli(ADP-Ribose) Polimerases/química , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/metabolismo , Especificidade por SubstratoRESUMO
Alkyl and aryl halides have been studied extensively as radical precursors; however, mild and less toxic conditions for the activation of alkyl bromides toward alkyl radicals are still desirable. Reported here is a reductive radical conjugate addition that allows for the formation of alkyl radicals via activation of alkyl bromides through cobalt/iridium catalysis. The developed conditions are emphasized in the broad substrate scope presented, including benzylic halides and halides containing free alcohols, silanes, and chlorides.
RESUMO
Artificial intelligence and machine learning have demonstrated their potential role in predictive chemistry and synthetic planning of small molecules; there are at least a few reports of companies employing in silico synthetic planning into their overall approach to accessing target molecules. A data-driven synthesis planning program is one component being developed and evaluated by the Machine Learning for Pharmaceutical Discovery and Synthesis (MLPDS) consortium, comprising MIT and 13 chemical and pharmaceutical company members. Together, we wrote this perspective to share how we think predictive models can be integrated into medicinal chemistry synthesis workflows, how they are currently used within MLPDS member companies, and the outlook for this field.
Assuntos
Técnicas de Química Sintética/métodos , Química Farmacêutica/métodos , Aprendizado de Máquina , Indústria Química/métodos , Descoberta de Drogas/métodos , Modelos Químicos , Pesquisa Farmacêutica/métodosRESUMO
Inhibition of the poly(ADP-ribose) polymerase (PARP) family of enzymes has become an attractive therapeutic strategy in oncology and beyond; however, chemical tools to profile PARP engagement in live cells are lacking. Herein, we report the design and application of PARPYnD, the first photoaffinity probe (AfBP) for PARP enzymes based on triple PARP1/2/6 inhibitor AZ9482, which induces multipolar spindle (MPS) formation in breast cancer cells. PARPYnD is a robust tool for profiling PARP1/2 and is used to profile clinical PARP inhibitor olaparib, identifying several novel off-target proteins. Surprisingly, while PARPYnD can enrich recombinant PARP6 spiked into cellular lysates and inhibits PARP6 in cell-free assays, it does not label PARP6 in intact cells. These data highlight an intriguing biomolecular disparity between recombinant and endogenous PARP6. PARPYnD provides a new approach to expand our knowledge of the targets of this class of compounds and the mechanisms of action of PARP inhibitors in cancer.
Assuntos
Aziridinas/farmacologia , Marcadores de Fotoafinidade/farmacologia , Ftalazinas/farmacologia , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Aziridinas/síntese química , Linhagem Celular Tumoral , Humanos , Marcadores de Fotoafinidade/síntese química , Ftalazinas/síntese química , Piperazinas/farmacologia , Poli(ADP-Ribose) Polimerase-1/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Proteômica , Raios UltravioletaRESUMO
While carbon-heteroatom cross-coupling reactions have been extensively studied, many methods are specific and limited to a particular set of substrates or functional groups. Reported here is a general method that allows for C-O, C-N and C-S cross-coupling reactions under one general set of conditions. We propose that an energy transfer pathway, in which an iridium photosensitizer produces an excited nickel(II) complex, is responsible for the key reductive elimination step that couples aryl bromides, iodides, and chlorides to 1° and 2° alcohols, amines, thiols, carbamates, and sulfonamides, and is amenable to scale up via a flow apparatus.
RESUMO
The three-dimensional conformations adopted by a free ligand in solution impact bioactivity and physicochemical properties. Solution 1D NMR spectra inherently contain information on ligand conformational flexibility and three-dimensional shape, as well as the propensity of the free ligand to fully preorganize into the bioactive conformation. Herein we discuss some key learnings, distilled from our experience developing potent and selective synthetic macrocyclic inhibitors, including Mcl-1 clinical candidate AZD5991. Case studies have been selected from recent oncology research projects, demonstrating how 1D NMR conformational signatures can complement X-ray protein-ligand structural information to guide medicinal chemistry optimization. Learning to extract free ligand conformational information from routinely available 1D NMR signatures has proven to be fast enough to guide medicinal chemistry decisions within design cycles for compound optimization.
Assuntos
Desenho de Fármacos , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Cinética , Ligantes , Compostos Macrocíclicos/síntese química , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Proteína de Sequência 1 de Leucemia de Células Mieloides/química , Conformação Proteica , Relação Estrutura-AtividadeRESUMO
Mcl-1 is a member of the Bcl-2 family of proteins that promotes cell survival by preventing induction of apoptosis in many cancers. High expression of Mcl-1 causes tumorigenesis and resistance to anticancer therapies highlighting the potential of Mcl-1 inhibitors as anticancer drugs. Here, we describe AZD5991, a rationally designed macrocyclic molecule with high selectivity and affinity for Mcl-1 currently in clinical development. Our studies demonstrate that AZD5991 binds directly to Mcl-1 and induces rapid apoptosis in cancer cells, most notably myeloma and acute myeloid leukemia, by activating the Bak-dependent mitochondrial apoptotic pathway. AZD5991 shows potent antitumor activity in vivo with complete tumor regression in several models of multiple myeloma and acute myeloid leukemia after a single tolerated dose as monotherapy or in combination with bortezomib or venetoclax. Based on these promising data, a Phase I clinical trial has been launched for evaluation of AZD5991 in patients with hematological malignancies (NCT03218683).
Assuntos
Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Leucemia Mieloide Aguda/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Animais , Bortezomib/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Mieloma Múltiplo/patologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Ratos , Ratos Nus , Sulfonamidas/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
: PARP proteins represent a class of post-translational modification enzymes with diverse cellular functions. Targeting PARPs has proven to be efficacious clinically, but exploration of the therapeutic potential of PARP inhibition has been limited to targeting poly(ADP-ribose) generating PARP, including PARP1/2/3 and tankyrases. The cancer-related functions of mono(ADP-ribose) generating PARP, including PARP6, remain largely uncharacterized. Here, we report a novel therapeutic strategy targeting PARP6 using the first reported PARP6 inhibitors. By screening a collection of PARP compounds for their ability to induce mitotic defects, we uncovered a robust correlation between PARP6 inhibition and induction of multipolar spindle (MPS) formation, which was phenocopied by PARP6 knockdown. Treatment with AZ0108, a PARP6 inhibitor with a favorable pharmacokinetic profile, potently induced the MPS phenotype, leading to apoptosis in a subset of breast cancer cells in vitro and antitumor effects in vivo. In addition, Chk1 was identified as a specific substrate of PARP6 and was further confirmed by enzymatic assays and by mass spectrometry. Furthermore, when modification of Chk1 was inhibited with AZ0108 in breast cancer cells, we observed marked upregulation of p-S345 Chk1 accompanied by defects in mitotic signaling. Together, these results establish proof-of-concept antitumor efficacy through PARP6 inhibition and highlight a novel function of PARP6 in maintaining centrosome integrity via direct ADP-ribosylation of Chk1 and modulation of its activity. SIGNIFICANCE: These findings describe a new inhibitor of PARP6 and identify a novel function of PARP6 in regulating activation of Chk1 in breast cancer cells.
Assuntos
ADP Ribose Transferases/antagonistas & inibidores , Neoplasias da Mama/metabolismo , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Fuso Acromático/efeitos dos fármacos , Fuso Acromático/metabolismo , Animais , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 1 do Ponto de Checagem/metabolismo , Modelos Animais de Doenças , Feminino , Humanos , Camundongos , Inibidores de Poli(ADP-Ribose) Polimerases/química , Transdução de Sinais/efeitos dos fármacos , Especificidade por Substrato , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The design and synthesis of a novel series of 2,6-disubstituted pyrazine derivatives as CK2 kinase inhibitors is described. Structure-guided optimization of a 5-substituted-3-thiophene carboxylic acid screening hit (3a) led to the development of a lead compound (12b), which shows inhibition in both enzymatic and cellular assays. Subsequent design and hybridization efforts also led to the unexpected identification of analogs with potent PIM kinase activity (14f).
Assuntos
Caseína Quinase II/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Pirazinas/farmacologia , Linhagem Celular Tumoral , Desenho de Fármacos , Humanos , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Pirazinas/síntese química , Pirazinas/química , Pirazinas/farmacocinética , Relação Estrutura-AtividadeRESUMO
Cyclin-dependent kinase (CDK) 12 knockdown via siRNA decreases the transcription of DNA-damage-response genes and sensitizes BRCA wild-type cells to poly(ADP-ribose) polymerase (PARP) inhibition. To recapitulate this effect with a small molecule, we sought a potent, selective CDK12 inhibitor. Crystal structures and modeling informed hybridization between dinaciclib and SR-3029, resulting in lead compound 5 [(S)-2-(1-(6-(((6,7-difluoro-1H-benzo[d]imidazol-2-yl)methyl)amino)-9-ethyl-9H-purin-2-yl)piperidin-2-yl)ethan-1-ol]. Further structure-guided optimization delivered a series of selective CDK12 inhibitors, including compound 7 [(S)-2-(1-(6-(((6,7-difluoro-1H-benzo[d]imidazol-2-yl)methyl)amino)-9-isopropyl-9H-purin-2-yl)piperidin-2-yl)ethan-1-ol]. Profiling of this compound across CDK9, 7, 2, and 1 at high ATP concentration, single-point kinase panel screening against 352 targets at 0.1â µm, and proteomics via kinase affinity matrix technology demonstrated the selectivity. This series of compounds inhibits phosphorylation of Ser2 on the C-terminal repeat domain of RNA polymeraseâ II, consistent with CDK12 inhibition. These selective compounds were also acutely toxic to OV90 as well as THP1 cells.
Assuntos
Benzimidazóis/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Quinases Ciclina-Dependentes/antagonistas & inibidores , Piperidinas/síntese química , Purinas/química , Compostos de Piridínio/química , Benzimidazóis/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cristalização , Óxidos N-Cíclicos , Quinase 9 Dependente de Ciclina/antagonistas & inibidores , Desenho de Fármacos , Humanos , Indolizinas , Cinética , Fosforilação , Piperidinas/farmacologia , Ligação Proteica , Purinas/farmacologia , Compostos de Piridínio/farmacologia , RNA Polimerase II/metabolismo , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
[This corrects the article DOI: 10.1021/acsmedchemlett.6b00464.].
RESUMO
Phosphorylation of xenobiotics is rare, probably owing to a strong evolutionary pressure against it. This rarity may have attracted more attention recently as a result of intentionally designed kinase-substrate analogs that depend on kinase-catalyzed activation to form phosphorylated active drugs. We report a rare phosphorylated metabolite observed unexpectedly in mouse plasma samples after an oral dose of a Tankyrase inhibitor that was not intended to be a kinase substrate, i.e., (S)-2-(4-(6-(3,4-dimethylpiperazin-1-yl)-4-methylpyridin-3-yl)phenyl)-8-(hydroxymethyl)quinazolin-4(3H)-one (AZ2381). The phosphorylated metabolite was not generated in mouse hepatocytes. In vitro experiments showed that the phosphorylation of AZ2381 occurred in mouse whole blood with heparin as anticoagulant but not in mouse plasma. The phosphorylated metabolite was also produced in rat, dog, and human blood, albeit at lower yields than in mouse. Divalent metal ions are required for the phosphorylation since the reaction is inhibited by the metal chelator EDTA. Further investigations with different cellular fractions of mouse blood revealed that the phosphorylation of AZ2381 was mediated by erythrocytes but did not occur with leukocytes. The levels of 18O incorporation into the phosphorylated metabolite when inorganic 18O4-phosphate and γ-18O4-ATP were added to the mouse blood incubations separately suggested that the phosphoryl transfer was from inorganic phosphate rather than ATP. It remains unclear which enzyme present in red blood cells is responsible for this rare phosphorylation.
Assuntos
Eritrócitos/metabolismo , Fosfotransferases/metabolismo , Piperazinas/metabolismo , Quinazolinas/metabolismo , Tanquirases/antagonistas & inibidores , Xenobióticos/metabolismo , Administração Oral , Animais , Cães , Ácido Edético/farmacologia , Eritrócitos/efeitos dos fármacos , Feminino , Heparina/sangue , Heparina/metabolismo , Hepatócitos/metabolismo , Humanos , Camundongos , Camundongos SCID , Fosfatos/metabolismo , Fosforilação/efeitos dos fármacos , Piperazinas/sangue , Piperazinas/síntese química , Piperazinas/farmacologia , Quinazolinas/sangue , Quinazolinas/síntese química , Quinazolinas/farmacologia , Ratos , Xenobióticos/sangue , Xenobióticos/síntese química , Xenobióticos/farmacologiaRESUMO
Mcl-1 is a pro-apoptotic BH3 protein family member similar to Bcl-2 and Bcl-xL. Overexpression of Mcl-1 is often seen in various tumors and allows cancer cells to evade apoptosis. Here we report the discovery and optimization of a series of non-natural peptide Mcl-1 inhibitors. Screening of DNA-encoded libraries resulted in hit compound 1, a 1.5 µM Mcl-1 inhibitor. A subsequent crystal structure demonstrated that compound 1 bound to Mcl-1 in a ß-turn conformation, such that the two ends of the peptide were close together. This proximity allowed for the linking of the two ends of the peptide to form a macrocycle. Macrocyclization resulted in an approximately 10-fold improvement in binding potency. Further exploration of a key hydrophobic interaction with Mcl-1 protein and also with the moiety that engages Arg256 led to additional potency improvements. The use of protein-ligand crystal structures and binding kinetics contributed to the design and understanding of the potency gains. Optimized compound 26 is a <3 nM Mcl-1 inhibitor, while inhibiting Bcl-2 at only 5 µM and Bcl-xL at >99 µM, and induces cleaved caspase-3 in MV4-11 cells with an IC50 of 3 µM after 6 h.