Computational investigation of TGF-β receptor inhibitors for treatment of idiopathic pulmonary fibrosis: Field-based QSAR model and molecular dynamics simulation

Riboflavin protects against pancreatic cancer metastasis by targeting TGF-β receptor 1

The inhibition of transforming growth factor-β1 (TGF-β1) signaling by targeting TGF-β receptor 1 (TβR1) has been considered as an ideal approach for the prevention of pancreatic cancer metastasis. Utilizing a pharmacophore model for TβR1 inhibitors, candidate compounds with the potential TβR1 binding ability were screened from the U.S. Food and Drug Administration (FDA) database, and riboflavin (RF) with a highest fit value was chosen to investigate its binding ability to TβR1 and effect on TGF-β1 signaling in pancreatic cancer cells. Molecular docking and cellular thermal shift assay (CETSA) proved that RF at pharmacological concentrations could directly bind to TβR1. Further studies showed that pharmacological concentrations of RF in vitro could block TGF-β1 signaling, suppress the migration and invasion, and prevent epithelial-mesenchymal transition (EMT) process of pancreatic cancer cells in the absence or presence of TGF-β1 stimulation, indicating that RF presented anti-metastatic effect in pancreatic cancer cells. Knockdown of TβR1 could significantly attenuate the effects of RF on the migration and EMT process in pancreatic cancer cells, further confirming that the anti-metastatic effect of RF was achieved by blocking TGF-β1 signaling after binding to TβR1. Moreover, in a mouse model of pancreatic cancer metastasis, it was certified that RF administration could block lung and liver metastases, TGF-β1 signaling and EMT process of pancreatic cancer in vivo. In summary, our findings showed that RF could block TGF-β1 signaling by directly binding to TβR1, thereby suppressing the metastasis of pancreatic cancer cells by inhibiting EMT process both in vitro and in vivo.

Anti-Fibrosis Effects of Magnesium Lithospermate B in Experimental Pulmonary Fibrosis: By Inhibiting TGF-βRI/Smad Signaling

Pulmonary fibrosis is a severe and irreversible interstitial pulmonary disease with high mortality and few treatments. Magnesium lithospermate B (MLB) is a hydrosoluble component of Salvia miltiorrhiza and has been reported to have antifibrotic effects in other forms of tissue fibrosis. In this research, we studied the effects of MLB on pulmonary fibrosis and the underlying mechanisms. Our results indicated that MLB treatment (50 mg/kg) for seven days could attenuate bleomycin (BLM)-induced pulmonary fibrosis by reducing the alveolar structure disruption and collagen deposition in the C57 mouse model. MLB was also found to inhibit transforming growth factor-beta (TGF-β)-stimulated myofibroblastic transdifferentiation of human lung fibroblast cell line (MRC-5) cells and collagen production by human type II alveolar epithelial cell line (A549) cells, mainly by decreasing the expression of TGF-β receptor I (TGF-βRI) and regulating the TGF-β/Smad pathway. Further studies confirmed that the molecular mechanisms of MLB in BLM-induced pulmonary fibrosis mice were similar to those observed in vitro. In summary, our results demonstrated that MLB could alleviate experimental pulmonary fibrosis both in vivo and in vitro, suggesting that MLB has great potential for pulmonary fibrosis treatment.

Molecular docking, 3D-QSAR, and molecular dynamics simulations of thieno[3,2-b]pyrrole derivatives against anticancer targets of KDM1A/LSD1

Lysine-specific demethylase 1 (LSD1) is a histone-modifying enzyme, which has been proposed as a promising target for anticancer drug development. Extensive research on LSD1 inhibitors has been performed since its discovery. In order to get more information for lead identification and optimization, we carried out a molecular modeling study on a set of 43 thieno[3,2-b]pyrrole competitive inhibitors of LSD1 using three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations. Based on the co-crystallized conformer-based alignment (CCBA) method, 3D-QSAR model of thieno[3,2-b]pyrrole derivatives as LSD1 inhibitors was established. The significant statistics (q² = 0.595, r² = 0.959, r²_pred = 0.846) of the 3D-QSAR indicated the good predictive power and statistical reliability of this model. Based on the corresponding contour maps six LSD1 inhibitors were designed and their activities were predicted by 3D-QSAR model. Meanwhile, molecular docking was performed to simulate the probable binding modes between ligands and LSD1 protein. The molecular interactions mainly contributions to the binding affinity for LSD1 inhibitions were further supplemented by 100 ns MD simulations and binding free energy calculation.

Gaining deeper insights into the surface binding of bedaquiline analogues with the ATP synthase subunit C of Mycobacterium tuberculosis using molecular docking, molecular dynamics simulation and 3D-QSAR techniques

This computational study exclusively illustrates the key molecular features of bedaquiline and its analogues required for binding to mycobacterial ATP synthase.

In silico studies on p21-activated kinase 4 inhibitors: comprehensive application of 3D-QSAR analysis, molecular docking, molecular dynamics simulations, and MM-GBSA calculation

P21-activated kinase 4 (PAK4) is a serine/threonine protein kinase, which is associated with many cancer diseases, and thus being considered as a potential drug target. In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations were performed to explore the structure-activity relationship of a series of pyrropyrazole PAK4 inhibitors. The statistical parameters of comparative molecular field analysis (CoMFA, Q ² = 0.837, R ² = 0.990, and R ² _pred = 0.967) and comparative molecular similarity indices analysis (CoMSIA, Q ² = 0.720, R ² = 0.972, and R ² _pred = 0.946) were obtained from 3D-QSAR model, which exhibited good predictive ability and significant statistical reliability. The binding mode of PAK4 with its inhibitors was obtained through molecular docking study, which indicated that the residues of GLU396, LEU398, LYS350, and ASP458 were important for activity. Molecular mechanics generalized born surface area (MM-GBSA) method was performed to calculate the binding free energy, which indicated that the coulomb, lipophilic and van der Waals (vdW) interactions made major contributions to the binding affinity. Furthermore, through 100 ns MD simulations, we obtained the key amino acid residues and the types of interactions they participated in. Based on the constructed 3D-QSAR model, some novel pyrropyrazole derivatives targeting PAK4 were designed with improved predicted activities. Pharmacokinetic and toxicity predictions of the designed PAK4 inhibitors were obtained by the pkCSM, indicating these compounds had better absorption, distribution, metabolism, excretion and toxicity (ADMET) properties. Above research provided a valuable insight for developing novel and effective pyrropyrazole compounds targeting PAK4.

Quinone-thioether metabolites of hydroquinone play a dual role in promoting a vicious cycle of ROS generation: in vitro and in silico insights

Humans are exposed to hydroquinone (HQ) via diet, smoking, occupation, and even via inhalation of polluted air. Given its preferential distribution in kidney and liver, the impact of biotransformation on the nephrotoxicity and hepatotoxicity of HQ was evaluated. Indeed, HQ and its metabolites, benzoquinone, and quinone-thioethers (50, 100, 200, and 400 μM) all induced ROS-dependent cell death in both HK-2, a human kidney proximal epithelial cell line, and THLE-2, a human liver epithelial cell line, in a concentration-dependent manner. For a deeper insight into the biological mechanism of ROS stimulation, the bioinformatics database was reviewed. Intriguingly, 163 proteins were currently reported to form co-crystal complex with benzoquinone analogs, a large proportion of which are closely related to ROS generation. After a thorough assessment of the interaction affinity and binding energy, three key mitochondrial proteins that are particularly involved in electric transport, namely, cytochrome BC1, succinate dehydrogenase, and sulfide:quinone oxidoreductase, were highlighted for further verification. Their binding affinity and the action pattern were explored and validated by molecular docking and molecular dynamics simulations. Remarkably, quinone-thioether metabolites of HQ afforded high affinity to the above proteins that purportedly cause a surge in the generation of ROS. Therefore, HQ can be further converted into quinone-thioethers, which on one hand can function as substrates for redox cycling, and on the other hand may afford high affinity with key proteins evolved in mitochondrial electron transport system, leading to a vicious cycle of ROS generation. The combined data provide a prospective insight into the mechanisms of ROS motivation, expanding HQ-mediated toxicology profiles.

In silico exploration of aryl sulfonamide analogs as voltage-gated sodium channel 1.7 inhibitors by using 3D-QSAR, molecular docking study, and molecular dynamics simulations

It has been demonstrated by human genetics that the voltage-gated sodium channel Nav1.7 is currently a promising target for the treatment of pain. In this research, we performed molecular simulation works on a series of classic aryl sulfonamide Nav1.7 inhibitors using three-dimensional quantitative structure-activity relationships (3D-QSAR), molecular docking and molecular dynamics (MD) simulations for the first time to explore the correlation between their structures and activities. The results of the relevant statistical parameters of comparative molecular field analyses (CoMFA) and comparative molecular similarity indices analyses (CoMSIA) had been verified to be reasonable, and the deep relationship between the structures and activities of these inhibitors was obtained by analyzing the contour maps. The generated 3D-QSAR model showed a good predictive ability and provided valuable clues for the rational modification of molecules. The interactions between compounds and proteins were modeled by molecular docking studies. Finally, accuracy of the docking results and stability of the complexes were verified by 100 ns MD simulations. Detailed information on the key residues at the binding site and the types of interactions they participate in involved was obtained. The van der Waals energy contributed the most in the molecular binding process according to the calculation of binding free energy. All research results provided a good basis for further research on novel and effective Nav1.7 inhibitors.