Design, synthesis and SAR study of 2-aminopyridine derivatives as potent and selective JAK2 inhibitors

Therapeutic potential of anticancer activity of nitrogen-containing heterocyclic scaffolds as Janus kinase (JAK) inhibitor: Biological activity, selectivity, and structure-activity relationship

The JAK-STAT signalling pathway is primarily involved in cytokine signalling and induces various factors namely, erythropoietin, thrombopoietin, interferons, interleukins, and granulocyte colony-stimulating factors. These factors tremendously influenced understanding human health and illness, specifically cancer. Inhibiting the JAK/STAT pathway offers enormous therapeutic promises against cancer. Many JAK inhibitors are now being studied due to their efficacy in various cancer treatments. Further, the Nitrogen-heterocyclic (N-heterocyclic) scaffold has always shown to be a powerful tool for designing and discovering synthetic compounds with diverse pharmacological characteristics. The review focuses on several FDA-approved JAK inhibitors and their systematic categorization. The medicinal chemistry perspective is highlighted and classified review on the basis of N-heterocyclic molecules. Several examples of designing strategies of N-heterocyclic rings including pyrrolo-azepine, purine, 1H-pyrazolo[3,4-d]pyrimidine, 1H-pyrrolo[2,3-b]pyridine, pyrazole, thieno[3,2-d] pyrimidine, and, pyrimidine-based derivatives and their structure-activity relationships (SAR) are discussed. Among the various N-heterocyclic-based JAK inhibitors pyrimidine-containing compound 1 exhibited excellent inhibition activity against JAK2WT and mutated-JAK2V617F with IC50 of 2.01 and 18.84 nM respectively. Amino pyrimidine-containing compound 6 and thiopheno[3,2-d]pyrimidine-containing compound 13 expressed admirable JAK3 inhibition activity with IC50 of 1.7 nM and 1.38 nM respectively. Our review will support the medicinal chemists in refining and directing the development of novel N-heterocyclic-based JAK inhibitors.

Molecular modeling of novel 2-aminopyridine derivatives as potential JAK2 inhibitors: a rational strategy for promising anticancer agents

Janus kinase 2(JAK2) is a potential target for anticancer drugs in the treatment of numerous myeloproliferative diseases due to its central role in the JAK/STAT signaling cascade. In this study, the binding behavior of 2 amino-pyridine derivatives as JAK2 inhibitors was investigated by using multifaceted strategies including 3D-QSAR, molecular docking, Fingerprint analysis, MD simulations, and MM-PBSA calculations. A credible COMFA (q2 = 0.606 and r2 = 0.919) and COMSIA (q2 = 0.641 and r2 = 0.992) model was developed, where the internal and external validation revealed that the obtained 3D-QSAR models could be capable of predicting bioactivities of JAK2 inhibitors. The structural criteria provided by the contour maps of model were used to computationally develop more potent 100 new JAK2 inhibitors. Docking studies were conducted on the model data set and newly developed compounds (in-house library) to demonstrate their binding mechanism and highlight the key interacting residues within JAK2 active site. The selected docked complexes underwent MD simulation (100 ns), which contributed in the further study of the binding interactions. Binding free energy analyses (MMGB/PBSA) revealed that key residues such as Glu930, Leu932 (hinge region), Asp939 (solvent accessible region), Arg980, Asn981and Asp994 (catalytic site) have a significantly facilitate ligand-protein interactions through H-bonding and van der Waals interactions. The preliminary in-silico ADMET evaluation revealed encouraging results for all the modeled and in-house library compounds. The findings of this research have the potential to offer valuable recommendations for the advancement of novel, potent, and efficacious JAK2 inhibitors. Overall, this work has successfully employed a wide range of computer-based methodologies to understand the interaction dynamics between 2-amino-pyridine derivatives and the JAK2 enzyme, which is a crucial target in myeloproliferative disorders.Communicated by Ramaswamy H. Sarma.

Medicinal chemistry perspective of JAK inhibitors: synthesis, biological profile, selectivity, and structure activity relationship

JAK-STAT signalling pathway was discovered more than quarter century ago. The JAK-STAT pathway protein is considered as one of the crucial hubs for cytokine secretion which mediates activation of different inflammatory, cellular responses and hence involved in different etiological factors. The various etiological factors involved are haematopoiesis, immune fitness, tissue repair, inflammation, apoptosis, and adipogenesis. The presence of the active mutation V617K plays a significant role in the progression of the JAK-STAT pathway-related disease. Consequently, targeting the JAK-STAT pathway could be a promising therapeutic approach for addressing a range of causative factors. In this current review, we provided a comprehensive discussion for the in-detail study of anatomy and physiology of the JAK-STAT pathway which contributes structural domain rearrangement, activation, and negative regulation associated with the downstream signaling pathway, relationship between different cytokines and diseases. This review also discussed the recent development of clinical trial entities. Additionally, this review also provides updates on FDA-approved drugs. In the current investigation, we have classified recently developed small molecule inhibitors of JAK-STAT pathway according to different chemical classes and we emphasized their synthetic routes, biological evaluation, selectivity, and structure-activity relationship.

Toxicity of tributyltin chloride on haarder (Liza haematocheila) after its acute exposure: Bioaccumulation, antioxidant defense, histological, and transcriptional analyses

Liza haematocheila is exposed to various chemical contaminants from anthropogenic sources, including tributyltin chloride (TBTC). Yet the toxicity mechanism of TBTC on haarder remains unclear. The haarder was exposed to different doses (0, 10%, 20%, and 50% of LC₅₀-96 h) of TBTC. In this study, the results revealed its high bioaccumulation in the livers and significant alteration for development. The activities of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase decreased after 96-h exposure to TBTC, this accompanied by an increased malondialdehyde level. TBTC exposure caused the intense production of reactive oxygen species, a reduction in total blood cell count in serum, and apoptosis-related alterations in livers, indicating that enhanced oxidative stress occurred in the process of TBTC exposure. Histological results revealed angiorrhexis and infiltration of inflammatory cells, vacuolar degeneration of hepatocytes in the livers, and swelling, fusion, and disintegration of gill organs. Interestingly, the obtained transcriptional profiles indicated that high doses of TBTC caused energy disorder, apoptosis, and adipogenesis restriction mediated by cytokines and adipokines in Jak-STAT and adipocytokine signaling pathways. In summary, acute exposure to high doses of TBTC could impair the antioxidant system and pathways related to energy, apoptosis and adipogenesis, eventually posing a serious challenge to the fitness of haarder individuals and its fish populations as marine resources.