RESUMO
Hypoxia inducible factor (HIF) is a heterodimeric transcription factor composed of an oxygen-regulated α subunit and a constitutively expressed ß subunit that serves as the master regulator of the cellular response to low oxygen concentrations. The HIF transcription factor senses and responds to hypoxia by significantly altering transcription and reprogramming cells to enable adaptation to a hypoxic microenvironment. Given the central role played by HIF in the survival and growth of tumors in hypoxia, inhibition of this transcription factor serves as a potential therapeutic approach for treating a variety of cancers. Here, we report the identification, optimization, and characterization of a series of cyclic peptides that disrupt the function of HIF-1 and HIF-2 transcription factors by inhibiting the interaction of both HIF-1α and HIF-2α with HIF-1ß. These compounds are shown to bind to HIF-α and disrupt the protein-protein interaction between the α and ß subunits of the transcription factor, resulting in disruption of hypoxia-response signaling by our lead molecule in several cancer cell lines.
Assuntos
Fator 1 Induzível por Hipóxia , Neoplasias , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Peptídeos Cíclicos/farmacologia , Peptídeos Cíclicos/metabolismo , Hipóxia , Transdução de Sinais , Oxigênio/metabolismo , Hipóxia Celular , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias/tratamento farmacológicoRESUMO
We report an inhibitor of the homodimeric protein-protein interaction of the BCL6 oncoprotein, identified from a genetically encoded SICLOPPS library of 3.2 million cyclic hexapeptides in combination with a bacterial reverse two-hybrid system. This cyclic peptide is shown to bind the BTB domain of BCL6, disrupts its homodimerization, and subsequent binding of the SMRT2 corepressor peptide.
Assuntos
Biblioteca Gênica , Peptídeos Cíclicos/farmacologia , Proteínas Proto-Oncogênicas c-bcl-6/antagonistas & inibidores , Dimerização , Estrutura Molecular , Peptídeos Cíclicos/química , Peptídeos Cíclicos/genética , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-6/genéticaRESUMO
The neutrophil enzyme myeloperoxidase (MPO) promotes oxidative stress in numerous inflammatory pathologies by producing hypohalous acids. Its inadvertent activity is a prime target for pharmacological control. Previously, salicylhydroxamic acid was reported to be a weak reversible inhibitor of MPO. We aimed to identify related hydroxamates that are good inhibitors of the enzyme. We report on three hydroxamates as the first potent reversible inhibitors of MPO. The chlorination activity of purified MPO was inhibited by 50% by a 5 nm concentration of a trifluoromethyl-substituted aromatic hydroxamate, HX1. The hydroxamates were specific for MPO in neutrophils and more potent toward MPO compared with a broad range of redox enzymes and alternative targets. Surface plasmon resonance measurements showed that the strength of binding of hydroxamates to MPO correlated with the degree of enzyme inhibition. The crystal structure of MPO-HX1 revealed that the inhibitor was bound within the active site cavity above the heme and blocked the substrate channel. HX1 was a mixed-type inhibitor of the halogenation activity of MPO with respect to both hydrogen peroxide and halide. Spectral analyses demonstrated that hydroxamates can act variably as substrates for MPO and convert the enzyme to a nitrosyl ferrous intermediate. This property was unrelated to their ability to inhibit MPO. We propose that aromatic hydroxamates bind tightly to the active site of MPO and prevent it from producing hypohalous acids. This mode of reversible inhibition has potential for blocking the activity of MPO and limiting oxidative stress during inflammation.
Assuntos
Inibidores Enzimáticos/farmacologia , Hidrocarbonetos Aromáticos/farmacologia , Ácidos Hidroxâmicos/farmacologia , Peroxidase/química , Sequência de Aminoácidos , Sítios de Ligação , Linhagem Celular Tumoral , Inibidores Enzimáticos/química , Humanos , Hidrocarbonetos Aromáticos/síntese química , Hidrocarbonetos Aromáticos/química , Ácidos Hidroxâmicos/química , Cinética , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Neutrófilos/enzimologia , Peroxidase/antagonistas & inibidores , Peroxidase/metabolismo , Ligação ProteicaRESUMO
Libraries of dibasic compounds designed around the molecular scaffold of the DA(2)/ß(2) dual agonist sibenadet (Viozan™) have yielded a number of promising starting points that have been further optimised into novel potent and selective target molecules with required pharmacokinetic properties. From a shortlist, 31 was discovered as a novel, high potency, and highly efficacious ß(2)-agonist with high selectivity and a duration of action commensurable with once daily dosing.
Assuntos
Agonistas Adrenérgicos beta/síntese química , Agonistas Adrenérgicos beta/farmacologia , Química Farmacêutica/métodos , Animais , Asma/tratamento farmacológico , Broncodilatadores/farmacologia , Linhagem Celular Tumoral , AMP Cíclico/metabolismo , Desenho de Fármacos , Cobaias , Humanos , Concentração Inibidora 50 , Modelos Químicos , Ligação Proteica , Doença Pulmonar Obstrutiva Crônica/tratamento farmacológico , Tiazóis/farmacologia , Fatores de TempoRESUMO
Starting from adenosine triphosphate (ATP), the identification of a novel series of P2Y(12) receptor antagonists and exploitation of their SAR is described. Modifications of the acidic side chain and the purine core and investigation of hydrophobic substituents led to a series of neutral molecules. The leading compound, 17 (AZD6140), is currently in a large phase III clinical trial for the treatment of acute coronary syndromes and prevention of thromboembolic clinical sequelae.