Anticancer activity and mechanism studies of photoactivated iridium(III) complexes toward lung cancer A549 cells

Cyclometalated iridium(III) compounds have been widely explored due to their outstanding photo-physical properties and multiple anticancer activities. In this paper, three cyclometalated iridium(III) compounds [Ir(ppy)2(DBDIP)]PF6 (5a), [Ir(bzq)2(DBDIP)]PF6 (5b), and [Ir(piq)2(DBDIP)]PF6 (5c) (ppy: 2-phenylpyridine; bzq: benzo[h]quinoline; piq: 1-phenylisoquinoline, and DBDIP: 2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1H-imidazo[4,5-f][1,10]phenanthroline) were synthesized and the mechanism of antitumor activity was investigated. Compounds photoactivated by visible light show strong cytotoxicity against tumor cells, especially toward A549 cells. Biological experiments such as migration, cellular localization, mitochondrial membrane potential and permeability, reactive oxygen species (ROS) and calcium ion level detection were performed, and they demonstrated that the compounds induced the apoptosis of A549 cells through a mitochondrial pathway. At the same time, oxidative stress caused by ROS production increases the release of damage-related molecules and the expression of porogen gasdermin D (GSDMD), and the content of LDH released from damaged cell membranes also increased. Besides, the content of the lipid peroxidation product, malondialdehyde (MDA), increased and the expression of GPX4 decreased. These indicate that the compounds promote cell death by combining ferroptosis and pyroptosis. The results reveal that cyclometalated iridium(III) compounds 5a-5c may be a potential chemotherapeutic agent for photodynamic therapy of cancers.

1,4-Benzodioxane, an evergreen, versatile scaffold in medicinal chemistry: A review of its recent applications in drug design

1,4-Benzodioxane has long been a versatile template widely employed to design molecules endowed with diverse bioactivities. Its use spans the last decades of medicinal chemistry until today concerning many strategies of drug discovery, not excluding the most advanced ones. Here, more than fifty benzodioxane-related lead compounds, selected from recent literature, are presented showing the different approaches with which they have been developed. Agonists and antagonists at neuronal nicotinic, α₁ adrenergic and serotoninergic receptor subtypes and antitumor and antibacterial agents form the most representative classes, but a variety of other biological targets are addressed by benzodioxane-containing compounds.

Construction of Quantitative Structure Activity Relationship (QSAR) Models to Predict Potency of Structurally Diversed Janus Kinase 2 Inhibitors

Janus kinase 2 (JAK2) inhibitors represent a promising therapeutic class of anticancer agents against many myeloproliferative disorders. Bioactivity data on pIC50 of 2229 JAK2 inhibitors were employed in the construction of quantitative structure-activity relationship (QSAR) models. The models were built from 100 data splits using decision tree (DT), support vector machine (SVM), deep neural network (DNN) and random forest (RF). The predictive power of RF models were assessed via 10-fold cross validation, which afforded excellent predictive performance with R2 and RMSE of 0.74 ± 0.05 and 0.63 ± 0.05, respectively. Moreover, test set has excellent performance of R2 (0.75 ± 0.03) and RMSE (0.62 ± 0.04). In addition, Y-scrambling was utilized to evaluate the possibility of chance correlation of the predictive model. A thorough analysis of the substructure fingerprint count was conducted to provide insights on the inhibitory properties of JAK2 inhibitors. Molecular cluster analysis revealed that pyrazine scaffolds have nanomolar potency against JAK2.

An Update on JAK Inhibitors

Janus kinases (JAKs) are a family of non-receptor tyrosine kinases, composed by four members, JAK1, JAK2, JAK3 and TYK2. JAKs are involved in different inflammatory and autoimmune diseases, as well as in malignancies, through the activation of the JAK/STAT signalling pathway. Furthermore, the V617F mutation in JAK2 was identified in patients affected by myeloproliferative neoplasms. This knowledge prompted researchers from academia and pharmaceutical companies to investigate this field in order to discover small molecule JAK inhibitors. These efforts recently afforded to the market approval of four JAK inhibitors. Despite the fact that all these drugs are pyrrolo[2,3-d]pyrimidine derivatives, many compounds endowed with different heterocyclic scaffolds have been reported in the literature as selective or multi-JAK inhibitors, and a number of them is currently being evaluated in clinical trials. In this review we will report many representative compounds that have been published in articles or patents in the last five years (period 2013-2017). The inhibitors will be classified on the basis of their chemical structure, focusing, when possible, on their structure activity relationships, selectivity and biological activity. For every class of derivatives, compounds disclosed before 2013 that have entered clinical trials will also be briefly reported, to underline the importance of a particular chemical scaffold in the search for new inhibitors.

Anti-tumor and Anti-angiogenic Ergosterols from Ganoderma lucidum

This study was carried out to isolate chemical constituents from the lipid enriched fraction of Ganoderma lucidum extract and to evaluate their anti-proliferative effect on tumor cells and human umbilical vein endothelial cells (HUVECs). Ergosterol derivatives (1-14) were isolated and purified from the lipid enriched fraction of G. lucidum. Their chemical structures were established by spectroscopic analyses or by comparison of mass and NMR spectral data with those reported previously. Amongst, compound 1 was purified and identified as a new one. All the compounds were evaluated for their anti-proliferative effect on human tumor cells and HUVECs in vitro. Compounds 9-13 displayed inhibitory activity against two types of human tumor cells and HUVECs, which indicated that these four compounds had both anti-tumor and anti-angiogenesis activities. Compound 2 had significant selective inhibition against two tumor cell lines, while 3 exhibited selective inhibition against HUVECs. The structure-activity relationships for inhibiting human HepG2 cells were revealed by 3D-QASR. Ergosterol content in different parts of the raw material and products of G. lucidum was quantified. This study provides a basis for further development and utilization of ergosterol derivatives as natural nutraceuticals and functional food ingredients, or as source of new potential antitumor or anti-angiogenesis chemotherapy agent.

Cytotoxic lanostane-type triterpenoids from the fruiting bodies of Ganoderma lucidum and their structure-activity relationships

We conducted a study of Ganoderma lucidum metabolites and isolated 35 lanostane-type triterpenoids, including 5 new ganoderols (1-5). By spectroscopy, we compared the structures of these compounds with known related compounds in this group. All of the isolated compounds were assayed for their effect against the human breast carcinoma cell line MDA-MB-231 and hepatocellular carcinoma cell line HepG2. Corresponding three-dimensional quantitative structure-activity relationship (3D-QSAR) models were built and analyzed using Discovery Studio. These results provide further evidence for anti-cancer constituents within Ganoderma lucidum, and may provide a theoretical foundation for designing novel therapeutic compounds.

Molecular modeling study of CP-690550 derivatives as JAK3 kinase inhibitors through combined 3D-QSAR, molecular docking, and dynamics simulation techniques

To develop more potent JAK3 kinase inhibitors, a series of CP-690550 derivatives were investigated using combined molecular modeling techniques, such as 3D-QSAR, molecular docking and molecular dynamics (MD). The leave-one-out correlation (q²) and non-cross-validated correlation coefficient (r²) of the best CoMFA model are 0.715 and 0.992, respectively. The q² and r² values of the best CoMSIA model are 0.739 and 0.995, respectively. The steric, electrostatic, and hydrophobic fields played important roles in determining the inhibitory activity of CP-690550 derivatives. Some new JAK3 kinase inhibitors were designed. Some of them have better inhibitory activity than the most potent Tofacitinib (CP-690550). Molecular docking was used to identify some key amino acid residues at the active site of JAK3 protein. 10ns MD simulations were successfully performed to confirm the detailed binding mode and validate the rationality of docking results. The calculation of the binding free energies by MMPBSA method gives a good correlation with the predicted biological activity. To our knowledge, this is the first report on MD simulations and free energy calculations for this series of compounds. The combination results of this study will be valuable for the development of potent and novel JAK3 kinase inhibitors.