RESUMO
We describe a protein proximity inducing therapeutic modality called Regulated Induced Proximity Targeting Chimeras or RIPTACs: heterobifunctional small molecules that elicit a stable ternary complex between a target protein (TP) selectively expressed in tumor cells and a pan-expressed protein essential for cell survival. The resulting co-operative protein-protein interaction (PPI) abrogates the function of the essential protein, thus leading to death selectively in cells expressing the TP. This approach leverages differentially expressed intracellular proteins as novel cancer targets, with the advantage of not requiring the target to be a disease driver. In this chemical biology study, we design RIPTACs that incorporate a ligand against a model TP connected via a linker to effector ligands such as JQ1 (BRD4) or BI2536 (PLK1) or CDK inhibitors such as TMX3013 or dinaciclib. RIPTACs accumulate selectively in cells expressing the HaloTag-FKBP target, form co-operative intracellular ternary complexes, and induce an anti-proliferative response in target-expressing cells.
Assuntos
Antineoplásicos , Proteínas de Ciclo Celular , Bibliotecas de Moléculas Pequenas , Humanos , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/síntese química , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Proliferação de Células/efeitos dos fármacos , Triazóis/química , Triazóis/farmacologia , Quinase 1 Polo-Like , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Azepinas/farmacologia , Azepinas/química , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Indolizinas/química , Indolizinas/farmacologia , Linhagem Celular Tumoral , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Ligantes , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/síntese química , Compostos Heterocíclicos com 2 Anéis/farmacologia , Compostos Heterocíclicos com 2 Anéis/química , Compostos Heterocíclicos com 2 Anéis/síntese química , Proteínas Nucleares/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas que Contêm Bromodomínio , Óxidos N-Cíclicos , Compostos de PiridínioRESUMO
While specific cell signaling pathway inhibitors have yielded great success in oncology, directly triggering cancer cell death is one of the great drug discovery challenges facing biomedical research in the era of precision oncology. Attempts to eradicate cancer cells expressing unique target proteins, such as antibody-drug conjugates (ADCs), T-cell engaging therapies, and radiopharmaceuticals have been successful in the clinic, but they are limited by the number of targets given the inability to target intracellular proteins. More recently, heterobifunctional small molecules such as Proteolysis Targeting Chimera (PROTACs) have paved the way for protein proximity inducing therapeutic modalities. Here, we describe a proof-of-concept study using novel heterobifunctional small molecules called Regulated Induced Proximity Targeting Chimeras or RIPTACs, which elicit a stable ternary complex between a target protein selectively expressed in cancer tissue and a pan-expressed protein essential for cell survival. The resulting cooperative protein:protein interaction (PPI) abrogates the function of the essential protein, thus leading to cell death selectively in cells expressing the target protein. This approach not only opens new target space by leveraging differentially expressed intracellular proteins but also has the advantage of not requiring the target to be a driver of disease. Thus, RIPTACs can address non-target mechanisms of resistance given that cell killing is driven by inactivation of the essential protein. Using the HaloTag7-FKBP model system as a target protein, we describe RIPTACs that incorporate a covalent or non-covalent target ligand connected via a linker to effector ligands such as JQ1 (BRD4), BI2536 (PLK1), or multi-CDK inhibitors such as TMX3013 or dinaciclib. We show that these RIPTACs exhibit positive co-operativity, accumulate selectively in cells expressing HaloTag7-FKBP, form stable target:RIPTAC:effector trimers in cells, and induce an anti-proliferative response in target-expressing cells. We propose that RIPTACs are a novel heterobifunctional therapeutic modality to treat cancers that are known to selectively express a specific intracellular protein.
RESUMO
SignificanceSTAT3 (signal transducer and activator of transcription 3) is a master transcription factor that organizes cellular responses to cytokines and growth factors and is implicated in inflammatory disorders. STAT3 is a well-recognized therapeutic target for human cancer and inflammatory disorders, but how its function is regulated in a cell type-specific manner has been a major outstanding question. We discovered that Stat3 imposes self-directed regulation through controlling transcription of its own regulator homeodomain-interacting protein kinase 2 (Hipk2) in a T helper 17 (Th17) cell-specific manner. Our validation of the functional importance of the Stat3-Hipk2 axis in Th17 cell development in the pathogenesis of T cell-induced colitis in mice suggests an approach to therapeutically treat inflammatory bowel diseases that currently lack a safe and effective therapy.
Assuntos
Colite , Fator de Transcrição STAT3 , Animais , Diferenciação Celular/genética , Colite/genética , Colite/metabolismo , Ativação Linfocitária , Camundongos , Proteínas Serina-Treonina Quinases/genética , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Células Th17RESUMO
Glioblastoma is a fatal disease in which most targeted therapies have clinically failed. However, pharmacological reactivation of tumour suppressors has not been thoroughly studied as yet as a glioblastoma therapeutic strategy. Tumour suppressor protein phosphatase 2A is inhibited by non-genetic mechanisms in glioblastoma, and thus, it would be potentially amendable for therapeutic reactivation. Here, we demonstrate that small molecule activators of protein phosphatase 2A, NZ-8-061 and DBK-1154, effectively cross the in vitro model of blood-brain barrier, and in vivo partition to mouse brain tissue after oral dosing. In vitro, small molecule activators of protein phosphatase 2A exhibit robust cell-killing activity against five established glioblastoma cell lines, and nine patient-derived primary glioma cell lines. Collectively, these cell lines have heterogeneous genetic background, kinase inhibitor resistance profile and stemness properties; and they represent different clinical glioblastoma subtypes. Moreover, small molecule activators of protein phosphatase 2A were found to be superior to a range of kinase inhibitors in their capacity to kill patient-derived primary glioma cells. Oral dosing of either of the small molecule activators of protein phosphatase 2A significantly reduced growth of infiltrative intracranial glioblastoma tumours. DBK-1154, with both higher degree of brain/blood distribution, and more potent in vitro activity against all tested glioblastoma cell lines, also significantly increased survival of mice bearing orthotopic glioblastoma xenografts. In summary, this report presents a proof-of-principle data for blood-brain barrier-permeable tumour suppressor reactivation therapy for glioblastoma cells of heterogenous molecular background. These results also provide the first indications that protein phosphatase 2A reactivation might be able to challenge the current paradigm in glioblastoma therapies which has been strongly focused on targeting specific genetically altered cancer drivers with highly specific inhibitors. Based on demonstrated role for protein phosphatase 2A inhibition in glioblastoma cell drug resistance, small molecule activators of protein phosphatase 2A may prove to be beneficial in future glioblastoma combination therapies.
RESUMO
Impairment of protein phosphatases, including the family of serine/threonine phosphatases designated PP2A, is essential for the pathogenesis of many diseases, including cancer. The ability of PP2A to dephosphorylate hundreds of proteins is regulated by over 40 specificity-determining regulatory "B" subunits that compete for assembly and activation of heterogeneous PP2A heterotrimers. Here, we reveal how a small molecule, DT-061, specifically stabilizes the B56α-PP2A holoenzyme in a fully assembled, active state to dephosphorylate selective substrates, such as its well-known oncogenic target, c-Myc. Our 3.6 Å structure identifies molecular interactions between DT-061 and all three PP2A subunits that prevent dissociation of the active enzyme and highlight inherent mechanisms of PP2A complex assembly. Thus, our findings provide fundamental insights into PP2A complex assembly and regulation, identify a unique interfacial stabilizing mode of action for therapeutic targeting, and aid in the development of phosphatase-based therapeutics tailored against disease specific phospho-protein targets.
Assuntos
Proteína Fosfatase 2/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Ativadores de Enzimas/metabolismo , Células HEK293 , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos Nus , Modelos Moleculares , Complexos Multiproteicos/metabolismo , Proteína Fosfatase 2/química , Subunidades ProteicasRESUMO
The bromodomain (BrD) is a conserved structural module found in chromatin- and transcription-associated proteins that acts as the primary reader for acetylated lysine residues. This basic activity endows BrD proteins with versatile functions in the regulation of protein-protein interactions mediating chromatin-templated gene transcription, DNA recombination, replication and repair. Consequently, BrD proteins are involved in the pathogenesis of numerous human diseases. In this Review, we highlight our current understanding of BrD biology, and discuss the latest development of small-molecule inhibitors targeting BrDs as emerging epigenetic therapies for cancer and inflammatory disorders.
Assuntos
Descoberta de Drogas/métodos , Epigênese Genética/efeitos dos fármacos , Domínios Proteicos/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Acetilação/efeitos dos fármacos , Animais , Código das Histonas/efeitos dos fármacos , Histonas/química , Histonas/genética , Humanos , Inflamação/tratamento farmacológico , Inflamação/genética , Modelos Moleculares , Neoplasias/tratamento farmacológico , Neoplasias/genética , Fatores de Transcrição/química , Fatores de Transcrição/genéticaRESUMO
Primary prostate cancer is generally treatable by androgen deprivation therapy, however, later recurrences of castrate-resistant prostate cancer (CRPC) that are more difficult to treat nearly always occur due to aberrant reactivation of the androgen receptor (AR). In this study, we report that CRPC cells are particularly sensitive to the growth-inhibitory effects of reengineered tricyclic sulfonamides, a class of molecules that activate the protein phosphatase PP2A, which inhibits multiple oncogenic signaling pathways. Treatment of CRPC cells with small-molecule activators of PP2A (SMAP) in vitro decreased cellular viability and clonogenicity and induced apoptosis. SMAP treatment also induced an array of significant changes in the phosphoproteome, including most notably dephosphorylation of full-length and truncated isoforms of the AR and downregulation of its regulatory kinases in a dose-dependent and time-dependent manner. In murine xenograft models of human CRPC, the potent compound SMAP-2 exhibited efficacy comparable with enzalutamide in inhibiting tumor formation. Overall, our results provide a preclinical proof of concept for the efficacy of SMAP in AR degradation and CRPC treatment.Significance: A novel class of small-molecule activators of the tumor suppressor PP2A, a serine/threonine phosphatase that inhibits many oncogenic signaling pathways, is shown to deregulate the phosphoproteome and to destabilize the androgen receptor in advanced prostate cancer. Cancer Res; 78(8); 2065-80. ©2018 AACR.
Assuntos
Ativadores de Enzimas/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/enzimologia , Proteína Fosfatase 2C/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/uso terapêutico , Animais , Linhagem Celular Tumoral , Ativadores de Enzimas/farmacologia , Xenoenxertos , Humanos , Masculino , Camundongos , Camundongos SCID , Fosfoproteínas/metabolismo , Proteína Fosfatase 2C/metabolismo , Proteômica , RNA Mensageiro/genética , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
INTRODUCTION: There is an unmet need of strategies for ex-vivo expansion of hematopoetic stem cells (HSCs) without loss of their primitive nature or stemness. We evaluate here a patent that attempts to address this need via key small molecules 1 and 40 that possess a pyrimido[4,5-b]indole core. Areas covered: (i) Discussion on literature reports of diverse strategies for ex-vivo expansion of stem cells. (ii) Synthetic scheme to 1, and general synthetic schemes for compounds 1-55 reported in the patent application. (iii) Analysis of the in vitro biological data for 1 and 40. Highlight here is: 1 and 40 when used in combination with StemReginin1 (SR1), an established aryl hydrocarbon receptor antagonist known for ex-vivo HSC expansion, demonstrate better HSC expansion relative to SR1 alone. (iv) Analysis of the in vivo biological data for 1 and 40. Expert opinion: Compelling evidence on the molecular mechanism of action of 1 and 40 is not provided making it difficult to optimize this series. It is suggested here that combining these molecules with homing molecules will possibly improve overall engraftment time and hematopoietic recovery. The numerous literature reports and biological data indicates that these pyrimido[4,5-b]indole derivatives are promising candidates for the development of potential therapies for hematopoietic ailments.
Assuntos
Transplante de Células-Tronco Hematopoéticas/métodos , Células-Tronco Hematopoéticas/citologia , Indóis/farmacologia , Animais , Células-Tronco Hematopoéticas/efeitos dos fármacos , Humanos , Indóis/química , Patentes como Assunto , Relação Estrutura-Atividade , Fatores de TempoRESUMO
Site-specific lysine acetylation and methylation on histones are critical post-translational modifications (PTMs) that govern ordered gene transcription in chromatin. Mis-regulation of these histone PTM-mediated processes has been shown to be associated with human diseases. Since the 2010 landmark reports of small molecules (+)-JQ1 and I-BET762 that target the acetyl-lysine 'reader' Bromodomain and Extra Terminal domain (BET) proteins, there have been relentless efforts to develop epigenetic therapy with small molecules to modulate molecular interactions of epigenome reader domain proteins with PTMs. In addition to BET, the other emerging targets include non-BET acetyl-lysine and methyl-lysine reader domains. This review covers the key chemical modulators of the aforementioned epigenome reader proteins.
Assuntos
Epigênese Genética/efeitos dos fármacos , Genômica , Neoplasias/tratamento farmacológico , Neoplasias/genética , Humanos , Inflamação/tratamento farmacológico , Inflamação/genética , Lisina/metabolismoRESUMO
To identify the structural features of 9H-pyrimido[4,5-b]indoles as microtubule depolymerizers, pyrimido[4,5-b]indoles 2-8 with varied substituents at the 2-, 4- and 5-positions were designed and synthesized. Nucleophilic displacement of 2,5-substituted-4-chloro-pyrimido[4,5-b]indoles with appropriate arylamines was the final step employed in the synthesis of target compounds 2-8. Compounds 2 and 6 had two-digit nanomolar potency (IC50) against MDA-MB-435, SK-OV-3 and HeLa cancer cells in vitro. Compounds 2 and 6 also depolymerized microtubules comparable to the lead compound 1. Compounds 2, 3, 6 and 8 were effective in cells expressing P-glycoprotein or the ßIII isotype of tubulin, mechanisms that are associated with clinical drug resistance to microtubule targeting drugs. Proton NMR and molecular modeling studies were employed to identify the structural basis for the microtubule depolymerizing activity of pyrimido[4,5-b]indoles.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos , Indóis/química , Indóis/farmacologia , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia , Aminação , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Resistência a Múltiplos Medicamentos , Humanos , Indóis/síntese química , Microtúbulos/metabolismo , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Pirimidinas/síntese química , Pirimidinas/química , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/síntese químicaRESUMO
Targeted cancer therapies, which act on specific cancer-associated molecular targets, are predominantly inhibitors of oncogenic kinases. While these drugs have achieved some clinical success, the inactivation of kinase signaling via stimulation of endogenous phosphatases has received minimal attention as an alternative targeted approach. Here, we have demonstrated that activation of the tumor suppressor protein phosphatase 2A (PP2A), a negative regulator of multiple oncogenic signaling proteins, is a promising therapeutic approach for the treatment of cancers. Our group previously developed a series of orally bioavailable small molecule activators of PP2A, termed SMAPs. We now report that SMAP treatment inhibited the growth of KRAS-mutant lung cancers in mouse xenografts and transgenic models. Mechanistically, we found that SMAPs act by binding to the PP2A Aα scaffold subunit to drive conformational changes in PP2A. These results show that PP2A can be activated in cancer cells to inhibit proliferation. Our strategy of reactivating endogenous PP2A may be applicable to the treatment of other diseases and represents an advancement toward the development of small molecule activators of tumor suppressor proteins.
Assuntos
Antineoplásicos/farmacologia , Ativadores de Enzimas/farmacologia , Proteína Fosfatase 2/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Antineoplásicos/química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos , Ativação Enzimática , Ativadores de Enzimas/química , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Camundongos Transgênicos , Ligação Proteica , Proteína Fosfatase 2/química , Transdução de Sinais , Carga Tumoral , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In an effort to optimize the structural requirements for combined cytostatic and cytotoxic effects in single agents, a series of 5-(arylthio)-9H-pyrimido[4,5-b]indole-2,4-diamines 3-7 were synthesized and evaluated as inhibitors of receptor tyrosine kinases (RTKs) as well as thymidylate synthase (TS). The synthesis of these compounds involved the nucleophilic displacement of the common intermediate 5-bromo/5-chloro-9H-pyrimido[4,5-b]indole-2,4-diamine with appropriate aryl thiols. A novel four step synthetic scheme to the common intermediate was developed which is more efficient relative to the previously reported six-step sequence. Biological evaluation of these compounds indicated dual activity in RTKs and human TS (hTS). In the VEGFR-2 assay, compound 5 was equipotent to the standard compound semaxanib and was better than standard TS inhibitor pemetrexed, in the hTS assay. Compounds 3, 6 and 7 were nanomolar inhibitors of hTS and were several fold better than pemetrexed.
Assuntos
Antineoplásicos/farmacologia , Compostos Heterocíclicos com 3 Anéis/farmacologia , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/farmacologia , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Timidilato Sintase/antagonistas & inibidores , Inibidores da Angiogênese/síntese química , Inibidores da Angiogênese/farmacologia , Animais , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Cisplatino/farmacologia , Antagonistas do Ácido Fólico/síntese química , Antagonistas do Ácido Fólico/farmacologia , Compostos Heterocíclicos com 3 Anéis/síntese química , Humanos , Indóis/síntese química , Camundongos , Pemetrexede/farmacologia , Inibidores de Proteínas Quinases/síntese química , Pirimidinas/síntese química , Pirróis/farmacologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Cancer cells have a unique metabolic profile and mitochondria have been shown to play an important role in chemoresistance, tumor progression and metastases. This unique profile can be exploited by mitochondrial-targeted anticancer therapies. A small anticancer molecule, AG311, was previously shown to possess anticancer and antimetastatic activity in two cancer mouse models and to induce mitochondrial depolarization. This study defines the molecular effects of AG311 on the mitochondria to elucidate its observed efficacy. AG311 was found to competitively inhibit complex I activity at the ubiquinone-binding site. Complex I as a target for AG311 was further established by measuring oxygen consumption rate in tumor tissue isolated from AG311-treated mice. Cotreatment of cells and animals with AG311 and dichloroacetate, a pyruvate dehydrogenase kinase inhibitor that increases oxidative metabolism, resulted in synergistic cell kill and reduced tumor growth. The inhibition of mitochondrial oxygen consumption by AG311 was found to reduce HIF-1α stabilization by increasing oxygen tension in hypoxic conditions. Taken together, these results suggest that AG311 at least partially mediates its antitumor effect through inhibition of complex I, which could be exploited in its use as an anticancer agent.
Assuntos
Complexo I de Transporte de Elétrons/antagonistas & inibidores , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Indóis/uso terapêutico , Pirimidinas/uso terapêutico , Animais , Hipóxia Celular , Humanos , CamundongosRESUMO
The phenothiazine and dibenzazepine tricyclics are potent neurotropic drugs with a documented but underutilized anti-cancer side effect. Reengineering these agents (TFP, CPZ, CIP) by replacing the basic amine with a neutral polar functional group (e.g., RTC-1, RTC-2) abrogated their CNS effects as demonstrated by in vitro pharmacological assays and in vivo behavioral models. Further optimization generated several phenothiazines and dibenzazepines with improved anti-cancer potency, exemplified by RTC-5. This new lead demonstrated efficacy against a xenograft model of an EGFR driven cancer without the neurotropic effects exhibited by the parent molecules. Its effects were attributed to concomitant negative regulation of PI3K-AKT and RAS-ERK signaling.
Assuntos
Antineoplásicos/química , Compostos Heterocíclicos com 3 Anéis/química , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dibenzazepinas/química , Compostos Heterocíclicos com 3 Anéis/farmacologia , Compostos Heterocíclicos com 3 Anéis/uso terapêutico , Humanos , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Fenotiazinas/química , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transplante Heterólogo , Proteínas Vesiculares de Transporte de Monoamina/antagonistas & inibidores , Proteínas Vesiculares de Transporte de Monoamina/metabolismoRESUMO
Inhibition of receptor tyrosine kinase (RTK) signaling pathways is an important area for the development of novel anticancer agents. Numerous multikinase inhibitors (MKIs) have been recently approved for the treatment of cancer. Vascular endothelial growth factor receptor-2 (VEGFR-2) is the principal mediator of tumor angiogenesis. In an effort to develop ATP-competitive VEGFR-2 selective inhibitors the 5-chloro-N(4)-substituted phenyl-9H-pyrimido[4,5-b]indole-2,4-diamine scaffold was designed. The synthesis of the target compounds involved N-(4,5-dichloro-9H-pyrimido[4,5-b]indol-2-yl)-2,2-dimethylpropanamide) as a common intermediate. A nucleophilic displacement of the 4-chloro group of the common intermediate by appropriately substituted anilines afforded the target compounds. Biological evaluation indicated that compound 5 is a potent and selective VEGFR-2 inhibitor comparable to sunitinib and semaxinib.
Assuntos
Inibidores da Angiogênese/química , Diaminas/química , Indóis/química , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Inibidores da Angiogênese/síntese química , Inibidores da Angiogênese/farmacologia , Linhagem Celular Tumoral , Diaminas/síntese química , Diaminas/farmacologia , Halogenação , Humanos , Indóis/síntese química , Indóis/farmacologia , Pirimidinas/síntese química , Pirimidinas/química , Pirimidinas/farmacologia , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
A series of fourteen N(4)-(substituted phenyl)-N(4)-alkyl/desalkyl-9H-pyrimido[4,5-b]indole-2,4-diamines was synthesized as potential microtubule targeting agents. The synthesis involved a Fisher indole cyclization of 2-amino-6-hydrazinylpyrimidin-4(3H)-one with cyclohexanone, followed by oxidation, chlorination and displacement with appropriate anilines. Compounds 6, 14 and 15 had low nanomolar potency against MDA-MB-435 tumor cells and depolymerized microtubules. Compound 6 additionally had nanomolar GI(50) values against 57 of the NCI 60-tumor panel cell lines. Mechanistic studies showed that 6 inhibited tubulin polymerization and [(3)H]colchicine binding to tubulin. The most potent compounds were all effective in cells expressing P-glycoprotein or the ßIII isotype of tubulin, which have been associated with clinical drug resistance. Modeling studies provided the potential interactions of 6, 14 and 15 within the colchicine site.
Assuntos
Diaminas/química , Indóis/química , Microtúbulos/química , Pirimidinas/química , Moduladores de Tubulina/síntese química , Compostos de Anilina/química , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colchicina/química , Colchicina/metabolismo , Ciclização , Cicloexanonas/química , Diaminas/síntese química , Diaminas/toxicidade , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Microtúbulos/metabolismo , Simulação de Acoplamento Molecular , Oxirredução , Ligação Proteica , Estrutura Terciária de Proteína , Moduladores de Tubulina/química , Moduladores de Tubulina/toxicidadeRESUMO
Infection by the parasite Toxoplasma gondii (tg) can lead to toxoplasmosis in immunocompromised patients such as organ transplant, cancer and HIV/AIDS patients. The bifunctional thymidylate synthase-dihydrofolate reductase (TS-DHFR) enzyme is crucial for nucleotide synthesis in T. gondii, and represents a potential target to combat T. gondii infection. While species selectivity with drugs has been attained for DHFR, TS is much more conserved across species and specificity is significantly more challenging. We discovered novel substituted-9H-pyrimido[4,5-b]indoles 1-3 with single-digit nanomolar Ki for tgTS, two of which, 2 and 3, are 28- and 122-fold selective over human TS (hTS). The synthesis of these compounds, and their structures in complex with tgTS-DHFR are presented along with binding measurements and cell culture data. These results show, for the very first time, that in spite of the high degree of conservation of active site residues between hTS and the parasite TS, specificity has been accomplished via novel structures and provides a new target (TS) for selective drug development against parasitic infections.
RESUMO
With the goal of developing multitargeted receptor tyrosine kinase inhibitors that display potent inhibition against PDGFRß and VEGFR-2 we designed and synthesized eleven N(4)-(3-bromophenyl)-7-(substitutedbenzyl) pyrrolo[2,3-d]pyrimidines 9a-19a. These compounds were obtained from the key intermediate N(4)-(3-bromophenyl)-7H-pyrrolo[2,3-d]pyrimidine-2,4-diamine 29. Various arylmethyl groups were regiospecifically attached at the N7 of 29 via sodium hydride induced alkylation with substituted arylmethyl halides. Compounds 11a and 19a were potent dual inhibitors of PDGFRß and VEGFR-2. In a COLO-205, in vivo tumor mouse model 11a demonstrated inhibition of tumor growth, metastasis, and tumor angiogenesis that was better than or comparable to the standard compound TSU-68 (SU6668, 8).
Assuntos
Desenho de Fármacos , Inibidores de Proteínas Quinases/síntese química , Pirimidinas/química , Pirróis/química , Receptor beta de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidores , Animais , Sítios de Ligação , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Indóis/síntese química , Indóis/farmacologia , Indóis/uso terapêutico , Camundongos , Camundongos Nus , Simulação de Dinâmica Molecular , Neoplasias/tratamento farmacológico , Oxindóis , Propionatos/síntese química , Propionatos/farmacologia , Propionatos/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Estrutura Terciária de Proteína , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Pirróis/farmacologia , Pirróis/uso terapêutico , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Transplante Heterólogo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
Eighteen (2RS,6RS)-2-(4-methoxyphenyl)-6-(substituted ethyl)dihydro-2H-pyran-4(3H)ones were synthesized via a DDQ-mediated oxidative carbon-hydrogen bond activation reaction. Fourteen of these tetrahydropyrans were substituted with triazoles readily assembled via azide-alkyne click-chemistry reactions. Examples of a linked benzotriazole and pyrazole motif were also prepared. To complement the structural diversity, the alcohol substrates were obtained from stereoselective reductions of the tetrahydropyrone. This library provides rapid access to structurally diverse non-natural compounds to be screened against a variety of biological targets.