RESUMEN

Ponatinib and tofacitinib, established kinase inhibitors and FDA-approved for chronic myeloid leukemia and rheumatoid arthritis, are recently undergoing investigation in diverse clinical trials for potential repurposing. The aryl hydrocarbon receptor (AhR), a transcription factor influencing a spectrum of physiological and pathophysiological activities, stands as a therapeutic target for numerous diseases. This study employs molecular modelling tools and in vitro assays to identify ponatinib and tofacitinib as AhR ligands, elucidating their binding and molecular interactions in the AhR PAS-B domain. Molecular docking analyses revealed that ponatinib and tofacitinib occupy the central pocket within the primary cavity, similar to AhR agonists 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and (benzo[a]pyrene) B[a]P. Our simulations also showed that these compounds exhibit good stability, stabilizing many hot spots within the PAS-B domain, including the Dα-Eα loop, which serves as a regulatory element for the binding pocket. Binding energy calculations highlighted ponatinib's superior predicted affinity, revealing F295 as a crucial residue in maintaining strong interaction with the two compounds. Our in vitro data suggest that ponatinib functions as an AhR antagonist, blocking the downstream signaling of AhR pathway induced by TCDD and B[a]P. Additionally, both tofacitinib and ponatinib cause impairment in AhR-regulated CYP1A1 enzyme activity induced by potent AhR agonists. This study unveils ponatinib and tofacitinib as potential modulators of AhR, providing valuable insights into their therapeutic roles in AhR-associated diseases and enhancing our understanding of the intricate relationship between kinase inhibitors and AhR.

Asunto(s)

Imidazoles , Piperidinas , Piridazinas , Pirimidinas , Receptores de Hidrocarburo de Aril , Humanos , Sitios de Unión , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1A1/antagonistas & inhibidores , Imidazoles/farmacología , Imidazoles/química , Ligandos , Simulación del Acoplamiento Molecular , Piperidinas/farmacología , Piperidinas/química , Unión Proteica , Piridazinas/farmacología , Piridazinas/química , Pirimidinas/farmacología , Pirimidinas/química , Receptores de Hidrocarburo de Aril/metabolismo , Receptores de Hidrocarburo de Aril/agonistas , Receptores de Hidrocarburo de Aril/química , Receptores de Hidrocarburo de Aril/antagonistas & inhibidores , /farmacología

RESUMEN

The aryl hydrocarbon receptor (AhR) functions as a vital ligand-activated transcription factor, governing both physiological and pathophysiological processes. Notably, it responds to xenobiotics, leading to a diverse array of outcomes. In the context of drug repurposing, we present here a combined approach of utilizing structure-based virtual screening and molecular dynamics simulations. This approach aims to identify potential AhR modulators from Drugbank repository of clinically approved drugs. By focusing on the AhR PAS-B binding pocket, our screening protocol included binding affinities calculations, complex stability, and interactions within the binding site as a filtering method. Comprehensive evaluations of all DrugBank small molecule database revealed ten promising hits. This included flibanserin, butoconazole, luliconazole, naftifine, triclabendazole, rosiglitazone, empagliflozin, benperidol, nebivolol, and zucapsaicin. Each exhibiting diverse binding behaviors and remarkably very low binding free energy. Experimental studies further illuminated their modulation of AhR signaling, and showing that they are consistently reducing AhR activity, except for luliconazole, which intriguingly enhances the AhR activity. This work demonstrates the possibility of using computational modelling as a quick screening tool to predict new AhR modulators from extensive drug libraries. Importantly, these findings hold immense therapeutic potential for addressing AhR-associated disorders. Consequently, it offers compelling prospects for innovative interventions through drug repurposing.

Asunto(s)

Receptores de Hidrocarburo de Aril , Receptores de Hidrocarburo de Aril/metabolismo , Sitios de Unión , Unión Proteica , Dominios Proteicos , Ligandos

RESUMEN

Circular RNAs, which have covalently closed ends, are in the class of non-coding RNAs. Recent studies reveal that they are associated with various biochemical pathways. One such involvement of circular RNAs is in the onset of different types of cancers. Though the circular RNAs are known as non-coding RNAs, some of them are found to possess the capacities to code for proteins. One such circular RNA is hsa-circ-0000437 which is known to code for a short peptide referred to as CORO1C-47aa. The peptide has anti-angiogenic activity and is associated with the prevention of endometrial cancer. The peptide binds to the PAS-B domain of the Aryl hydrocarbon Receptor Nuclear Translocator (ARNT). However, till date only the amino acid sequence of the peptide is known and no structural details of the peptide are available. Therefore, in this work, our aim was to predict how the peptide would fold and what could be its possible ligand binding sites. We used computational tools to determine the structure of the peptide refined further by molecular dynamics simulations. We then performed molecular docking simulations of the peptide with its known binding partner ARNT to gain an insight into the modes of binding as the process is associated with endometrial cancer. The possible ligand binding sites along-with the natures of the possible other different ligands of the peptide were analyzed further. From this structure function analysis study, we tried to elucidate the plausible mechanism of the involvements of the peptide in the onset of endometrial cancer. This is the first report on the structural characterization of the peptide and its modes of interactions with the partner protein ARNT. This study may therefore be useful in determining the structures of new drug candidates for the treatment of endometrial cancer.

Asunto(s)

Neoplasias Endometriales , ARN Circular , Humanos , Femenino , ARN Circular/genética , Simulación del Acoplamiento Molecular , Ligandos , Péptidos/genética , Péptidos/metabolismo , Translocador Nuclear del Receptor de Aril Hidrocarburo , Proteínas/metabolismo , Neoplasias Endometriales/genética , Receptores de Hidrocarburo de Aril/genética

RESUMEN

Objective To construct a prokaryotic expression vector for a fusion protein, TAT protein transduction domain (PTD) and the PAS-B domain of hypoxia inducible factor 1?(HIF-1?), and then express and purifr the fusion protein. Methods The expression plasmids pTAT-PAS-B, pET-PAS-B and pTAT-EGFP were constructed respectively, and transformed into E. coli. BL21(DE3)pLysS strain to be induced by IPTG. The obtained proteins were analyzed by SDS-PAGE and Western blotting. The fusion protein were purified with Ni-NTA-His affinity chromatography. Results The three recombinant plasmids were constructed successfully. The objective fusion proteins were obtained by optimizing the conditions for expression and purification. Conclusion The successful expression and purification of the fusion protein TAT-HIF-1?PAS-B has laid the foundation for using it to modulate the activity of HIF-1? in vivo.