Challenges and Opportunities in the Crusade of BRAF Inhibitors: From 2002 to 2022.

Serine/threonine-protein kinase B-Raf (BRAF; RAF = rapidly accelerated fibrosarcoma) plays an important role in the mitogen-activated protein kinase (MAPK) signaling cascade. Somatic mutations in the BRAF gene were first discovered in 2002 by Davies et al., which was a major breakthrough in cancer research. Subsequently, three different classes of BRAF mutants have been discovered. This class includes class I monomeric mutants (BRAFV600), class II BRAF homodimer mutants (non-V600), and class III BRAF heterodimers (non-V600). Cancers caused by these include melanoma, thyroid cancer, ovarian cancer, colorectal cancer, nonsmall cell lung cancer, and others. In this study, we have highlighted the major binding pockets in BRAF protein, their active and inactive conformations with inhibitors, and BRAF dimerization and its importance in paradoxical activation and BRAF mutation. We have discussed the first-, second-, and third-generation drugs approved by the Food and Drug Administration and drugs under clinical trials with all four different binding approaches with DFG-IN/OUT and αC-IN/OUT for BRAF protein. We have investigated particular aspects and difficulties with all three generations of inhibitors. Finally, this study has also covered recent developments in synthetic BRAF inhibitors (from their discovery in 2002 to 2022), their unique properties, and importance in inhibiting BRAF mutants.

Establishment of models for reliability evaluation of 3CLpro ligand-receptor complexes with different binding sites.

Aim: Recent research shows that 3CLpro enzyme of SARS-CoV-2 is a significant target against COVID-19. Drug modeling allows the design of inhibitors of 3CLpro, but the accuracy of those methods remains unclear. Therefore, it is important to determine the trustworthiness of the designed ligand-receptor complexes. Method & materials: The authors built models for the reliability evaluation of 3CLpro complexes with ligands using an in-house developed AlteQ approach and complementarity principles. The models were based on 145 experimentally found 3CLpro complexes with ligands for five different binding sites. Result & conclusion: The obtained models correspond to linear regression with high values of correlation coefficients and can be successfully used to determine the reliability of the docked 3CLpro complexes with ligands.

COVID-19 is currently one of the most significant problems in the world. Research shows that the enzyme 3CLpro of SARS-CoV-2 is a main target for the development of potential anti-COVID-19 therapeutics. Drug modeling methods, especially docking studies, are utilized to design new compounds, however, the approaches have questionable precision. The authors present new models based on calculated electronic characteristics that can be used in drug design for the reliability assessment of SARS-CoV-2 3CLpro receptor­ligand complexes.

Proposition of a new allosteric binding site for potential SARS-CoV-2 3CL protease inhibitors by utilizing molecular dynamics simulations and ensemble docking.

The SARS-CoV-2 3CL protease (3CLpro) shows a high similarity with 3CL proteases of other beta-coronaviruses, such as SARS and MERS. It is the main enzyme involved in generating various non-structural proteins that are important for viral replication and is one of the most important proteins responsible for SARS-CoV-2 virulence. In this study, we have conducted an ensemble docking of molecules from the DrugBank database using both the crystallographic structure of the SARS-CoV-2 3CLpro, as well as five conformations obtained after performing a cluster analysis of a 300 ns molecular dynamics (MD) simulation. This procedure elucidated the inappropriateness of the active site for non-covalent inhibitors, but it has also shown that there exists an additional, more favorable, allosteric binding site, which could be a better target for non-covalent inhibitors, as it could prevent dimerization and activation of SARS-CoV-2 3CLpro. Two such examples are radotinib and nilotinib, tyrosine kinase inhibitors already in use for treatment of leukemia and which binding to the newly found allosteric binding site was also confirmed using MD simulations. Communicated by Ramaswamy H. Sarma.

The study of EGFR-ligand complex electron property relationship with biological activity.

The present investigation grounded on estimation of electron properties of the structures of EGFR proteins-ligand complexes using our laboratory-developed methodology AlteQ approach, which describes the molecular electron density of the complex in space for a certain point in three-dimensional coordinates. Briefly, the system embodies molecular electron density as a sum of Slater's type atomic increments of the molecular system. Further, using this methodology, we calculated different electron characteristics of selected EGFR protein-ligand complexes and established the relationship between different electron properties with their experimental pharmacological activity value (pIC50). The study suggested that EGFR inhibitory activity has higher correlation with intermolecular contacts of H with pi-system of aromatic ring between protein and ligands. Therefore, this created model has impact to identify and design potential ligands against EGFR in anticancer drug discovery.Communicated by Ramaswamy H. Sarma.

Electronic properties investigation of human dihydrofolate reductase complexes with ligands.

Despite the fact that there are already drugs for cancer, they still show strong toxicity to the human organism. That is why it is necessary to establish the factors affecting activity in order to develop new, more effective drugs aimed at tumor cells, minimizing harm to healthy cells. The present research is based on electronic properties calculation of the complexes using AlteQ approach. In the focus of this study are complexes of human dihydrofolate reductase (hDHFR) with a series of known inhibitors bound in the active site. Further, a statistical analysis was performed to establish the relationships between a myriad electronic characteristics and IC50. The change in total volume and the change of own electrons number of hydrogen atoms in their atomic basins are identified as the descriptors correlating the most with the hDHFR inhibition potency. Additionally, two lipophilic parts of protein (Thr56, Ser59, Ile60 and Ile7, Val8, Ala9) were found, which act as a key factor in decreasing bioactivity. The depth analysis of intermolecular interactions showed that the interactions between water molecules and ligand play a crucial role in hDHFR inhibition. Furthermore, the molecular dynamics simulations were used for deeper understanding of the structural inhibition, each for 50 ns time scale in explicit water conditions. Thus, the AlteQ approach made it possible to determine the factors influencing the activity and evaluate them not only qualitatively, but also quantitatively.Communicated by Ramaswamy H. Sarma.

1,2,4-Triazole-conjugated 1,3,4-thiadiazole hybrid scaffolds: A potent ameliorant of carrageenan-induced inflammation by lessening proinflammatory mediators.

Inflammation acts as an alarming signal for the progression of various biological complications. Various reports in the literature have revealed that heterocycle-containing synthetic compounds have a restorative capability against acute and chronic inflammatory stages. In the current study, we synthesized a series of 1,2,4-triazole-conjugated 1,3,4-thiadiazole hybrid scaffolds and evaluated their impacts against carrageenan-induced paw edema and proinflammatory markers in Wistar rats. Further, 3D QSAR study (three-dimensional quantitative structure-activity relationships), ADMET (absorption, distribution, metabolism, and excretion) profiling, and docking studies were performed to determine the possible mechanism of the action of the derivatives. The study shows that the most active derivatives, 13f and 13g, have optimal logP, a higher anti-inflammatory activity score, and poor metabolism at various sites of cytochrome P450. The docking studies recommended that the synthesized compounds have a similar affinity as the ligands A307, 63X, and S58 to interact with tumor necrosis factor-α, COX-1, and COX-2. So, these molecules will definitely hold a promise for the future drug development initiative.

Quinazoline based 1,3,5-triazine derivatives as cancer inhibitors by impeding the phosphorylated RET tyrosine kinase pathway: Design, synthesis, docking, and QSAR study.

The present research focused on designing a quinazoline skeleton, framed via 1,3,5-triazine derivatives (QBT) through field mapping and alignment studies. The QBT derivatives were synthesized via time- and cost-effective protocol. The 3D-QSAR study, computational physicochemical properties, and ADME calculation of the derivatives were performed to establish the affinity towards the biological system. Molecular docking in the adenosine triphosphate binding site of the RET tyrosine kinase domain (PDB ID: 7IVU) was studied to elucidate vital structural residues necessary for bioactivity. The derivatives were evaluated for anticancer potency against TPC-1 cells (thyroid cancer), MCF-7 cells (breast cancer), and one normal cell line (human foreskin fibroblasts) via 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide assay followed by an in ovo CAM assay. The entire series of derivatives (8a-o) showed mild to significant anticancer potency against the selected cancer cell lines.