Binding Interactions of Ergotamine and Dihydroergotamine to 5-Hydroxytryptamine Receptor 1B (5-HT1b) Using Molecular Dynamics Simulations and Dynamic Network Analysis

Indole-containing pharmaceuticals: targets, pharmacological activities, and SAR studies

Indole is a prestigious heterocyclic skeleton widely found in both naturally-occurring and biologically-active compounds. Pharmaceutical agents containing an indole skeleton in their framework possess a wide range of pharmacological properties, including antiviral, antitumor, analgesic, and other therapeutic activities, and many indole-containing drugs have been proven to have excellent pharmacokinetic and pharmacological effects. Over the past few decades, the FDA has approved over 40 indole-containing drugs for the treatment of various clinical conditions, and the development of indole-related drugs has attracted significant attention from medicinal chemists. This review aims to provide an overview of all the approved drugs that contain an indole nucleus, focusing on their targets, pharmacological activities, and SAR studies.

Dihydroergotamine mesylate enhances the anti-tumor effect of sorafenib in liver cancer cells

Liver cancer is the most common and frequentlyoccurring cancer. In addition to radiotherapy, chemotherapy and surgery are recommended as part of liver cancer treatment. The efficacy of sorafenib and sorafenib-based combination treatment against tumors has been verified. Although, clinical trials have revealed that some individuals are not sensitive to sorafenib therapy, and current therapeutic approaches are ineffective. Consequently, it is urgent to explore effective drug combinations and innovative techniques for increasing the effectiveness of sorafenib in the curing of liver tumor. Herein, we show that dihydroergotamine mesylate (DHE), an anti-migraine agent, could effectively suppress liver cancer cells proliferation by inhibiting STAT3 activation. However, DHE can enhance the protein stability of Mcl-1 by activating ERK, making DHE less effective in apoptosis induction. Specifically, DHE enhances the effects of sorafenib on liver cancer cells, such as decreased viability and increased apoptosis. Furthermore, the mixture of sorafenib and DHE could enhance DHE-triggered STAT3 suppression and inhibit DHE-mediated ERK-Mcl-1 pathway activation. In vivo, the combination of sorafenib with DHE produced a substantial synergy in suppressing tumour growth and causing apoptosis, ERK inhibition and Mcl-1 degradation. These findings suggest that DHE can effectively inhibit cell proliferation and enhance sorafenib anti-cancer activity in liver cancer cells. The current study provides some new insights that DHE asa novel anti-liver cancer therapeutic agent has been shown to improve treatment outcomes of sorafenib, which might be helpful in order to advance sorafenib in liver cancer therapeutics.

In silico study of dimethyltryptamine analogues against 5-HT1B receptor: Molecular docking, dynamic simulations and ADMET prediction

Introduction: The 5-HT1B receptor has a potential role in various psychiatric disorders such as depression, anxiety, and post-traumatic stress disorder. The objective of this study was to perform docking and molecular dynamics simulation to evaluate at atomic level the behavior of N,N-dimethyltryptamine (DMT) on 5-HT1B receptor.Methods: In this study, initially, a search for DMT was performed using the PubChem database. Subsequently, molecular docking was executed using AutoDock Vina based in PyRx 0.8 with a 95% analogy. Additionally, ergotamine (ERG) and serotonin were used as control. Then, it ran a total of 100 ns molecular dynamics simulations on 5-HT1B bound with DMT, serotonin, 112814775, and ERG. Finally, pharmacokinetic prediction and IV acute toxicity for analogues and DMT were performed.Results: It was possible to show that 112814775 had the lowest binding energy with the receptor. In addition, 112814775 presented great conformational stability, low mobility, and stiffness compared to the control ligands: ERG, serotonin, and DMT subsequent dynamic analysis. With respect to the free energy calculation, contributions such as Van der Waals, electrostatics, and nonpolar interactions for all systems, were highlighted.Conclusion: 112814775 showed affinities with 5-HT1B receptor and evidenced notable behavior by molecular dynamic simulation according to root-mean-square deviation (RMSD), root-mean-square fluctuation (RMSF), solvent-accessible surface area (SASA), the radius of gyration, number of hydrogen bond, and free energy calculated. These results established the possible relevance of in-silico studies in search of DMT analogues against the 5-HT1B receptor, which may be associated with alterations such as depression and anxiety, and may become future study molecules for the treatment of this type of disorder.

Using the Intranasal Route to Administer Drugs to Treat Neurological and Psychiatric Illnesses: Rationale, Successes, and Future Needs

While the intranasal administration of drugs to the brain has been gaining both research attention and regulatory success over the past several years, key fundamental and translational challenges remain to fully leveraging the promise of this drug delivery pathway for improving the treatment of various neurological and psychiatric illnesses. In response, this review highlights the current state of understanding of the nose-to-brain drug delivery pathway and how both biological and clinical barriers to drug transport using the pathway can been addressed, as illustrated by demonstrations of how currently approved intranasal sprays leverage these pathways to enable the design of successful therapies. Moving forward, aiming to better exploit the understanding of this fundamental pathway, we also outline the development of nanoparticle systems that show improvement in delivering approved drugs to the brain and how engineered nanoparticle formulations could aid in breakthroughs in terms of delivering emerging drugs and therapeutics while avoiding systemic adverse effects.

Characterizing the potentially neuronal acetylcholinesterase reactivity toward chiral pyraclofos: Enantioselective insights from spectroscopy, in silico docking, molecular dynamics simulation and per-residue energy decomposition studies

Chiral organophosphorus agents are distributed ubiquitously in the environment, but the neuroactivity of these asymmetric chemicals to humans remains uncertain. This scenario was to explore the stereoselective neurobiological response of human acetylcholinesterase (AChE) to chiral pyraclofos at the enantiomeric scale, and then decipher the microscopic basis of enantioselective neurotoxicity of pyraclofos enantiomers. The results indicated that (R)-/(S)-pyraclofos can form the bioconjugates with AChE with a stoichiometric ratio of 1:1, but the neuronal affinity of (R)-pyraclofos (K = 6.31 × 10⁴ M^-1) with AChE was larger than that of (S)-pyraclofos (K = 1.86 × 10⁴ M^-1), and significant enantioselectivity was existed in the biochemical reaction. The modes of neurobiological action revealed that pyraclofos enantiomers were situated at the substrate binding domain, and the strength of the overall noncovalent bonds between (S)-pyraclofos and the residues was weaker than that of (R)-pyraclofos, resulting in the high inhibitory effect of (R)-pyraclofos toward the activity of AChE. Dynamic enantioselective biointeractions illustrated that the intervention of inherent conformational flexibility in the AChE-(R)-pyraclofos was greater than that of the AChE-(S)-pyraclofos, which arises from the big spatial displacement and the conformational flip of the binding domain composed of the residues Thr-64～Asn-89, Gly-122～Asp-134, and Thr-436～Tyr-449. Energy decomposition exhibited that the Gibbs free energies of the AChE-(R)-/(S)-pyraclofos were ΔG° = －37.4/－30.2 kJ mol^-1, respectively, and the disparity comes from the electrostatic energy during the stereoselective neurochemical reactions. Quantitative conformational analysis further confirmed the atomic-scale computational chemistry conclusions, and the perturbation of (S)-pyraclofos on the AChE's ordered conformation was lower than that of (R)-pyraclofos, which is germane to the interaction energies of the crucial residues, e.g. Tyr-124, Tyr-337, Asp-74, Trp-86, and Tyr-119. Evidently, this attempt will contribute mechanistic information to uncovering the neurobiological effects of chiral organophosphates on the body.