Potential Protein Phosphatase 2A Agents from Traditional Chinese Medicine against Cancer

Discovery of potential SARS-CoV 3CL protease inhibitors from approved antiviral drugs using: virtual screening, molecular docking, pharmacophore mapping evaluation and dynamics simulation

The spread of corona-virus disease 2019 (COVID-19) has been faster than any other corona-viruses that have succeeded in crossing the animal-human barrier. This disease, caused by the severe acute respiratory syndrome corona-virus 2 (SARS-CoV-2/2019-nCoV) posing a serious threat to global public health and local economies. There are three responsible for this disease; SARS-CoV-2, SARS-CoV and MERS-CoV. Whereas our goal is to test the affinity for a new class of compounds obtained from a hybridization of Chloroquine, Amodiaquine and Mefloquine with three targets SARS-CoV-2, SARS-CoV and MERS-CoV, in order to find new compounds as new inhibitors against Covid-19. In this work, we first used: the molecular docking/dynamics methods and ADME properties to study interaction and affinity between eight new compounds against three targets involved in the Covid-19. The results of the docking simulations and dynamics revealed that inhibitor of the malaria (Ligand 87) has an affinity to interact with SARS-CoV-2, SARS-CoV and MERS-CoV targets and they can be good inhibitors for treatment of Covid-19. Moreover, they give best affinity compared to the Remdesivir and Chloroquine and other clinical tests. The Pharmacokinetics was justified by means of lipophilicity and high coefficient of skin permeability. The in silico evaluation of ADME and drug-likeness revealed that L87 has higher absorption in the intestines with good bioavailability. However, an additional in vitro and/or in vivo experimental study should make it possible to verify the theoretical results obtained in silico.Communicated by Ramaswamy H. Sarma.

Biocomputational Screening of Natural Compounds against Acetylcholinesterase

Alzheimer's disease (AD) is the most common form of dementia and is characterized by irreversible and progressive neurodegeneration. Cholinergic dysfunction has been reported in AD, and several cholinesterase inhibitors, including natural compounds and synthetic analogs, have been developed to treat the disease. However, there is currently no treatment for AD, as most drug-like compounds have failed in clinical trials. Acetylcholinesterase (AChE) is the target of most drugs used commercially to treat AD. This work focused on screening natural compounds obtained from the ZINC database (224, 205 compounds) against AChE to identify those possibly capable of enabling the management of AD. Indirubin and dehydroevodiamine were the best potential AChE inhibitors with free binding energies of -10.03 and -9.00 kcal/mol, respectively. The key residue (His447) of the active site of AChE was found to participate in complex interactions with these two molecules. Six H-bonds were involved in the 'indirubin-AChE' interaction and three H-bonds in the 'dehydroevodiamine-AChE' interaction. These compounds were predicted to cross the blood-brain barrier (BBB) and to exhibit high levels of intestinal absorption. Furthermore, 'indirubin-AChE' and 'dehydroevodiamine-AChE' complexes were found to be stable, as determined by root mean square deviation (RMSD) during a 50 ns molecular dynamics simulation study. Based on the free binding energies and stabilities obtained by simulation studies, we recommend that experimental studies be undertaken on indirubin and dehydroevodiamine with a view towards their potential use as treatments for AD.

Discovery of novel serine/threonine protein phosphatase 1 inhibitors from traditional Chinese medicine through virtual screening and biological assays

Protein phosphatase 1 (PP1) is a critical regulator of several processes, such as muscle contraction, neuronal signaling, glycogen synthesis, and cell proliferation. Dysregulation of PP1 has recently been found to be implicated in cardiac dysfunctions, which indicates that PP1 could be an attractive therapeutic target. However, discovery of PP1 inhibitors with satisfied safety and efficiency is still a challenge. Here, in order to discover potential PP1 inhibitors, compounds extracted from traditional Chinese medicine (TCM) were screened by a novel integrated virtual screening protocol including pharmacophore modeling and docking approaches. Combined with protein phosphatase inhibition assay, ZINC43060554 showed strongly inhibitory activity with IC₅₀ values of 26.78 μM. Furthermore, molecular dynamics simulation and Molecular Mechanics/Generalized Born Surface Area binding free-energy analysis were performed to examine the stability of ligand binding modes. These novel scaffolds discovered in the present study can be used for rational design of PP1 inhibitors with high affinity.Communicated by Ramaswamy H. Sarma.

Selective reversal of BCRP-mediated MDR by VEGFR-2 inhibitor ZM323881

The expression of breast cancer resistant protein (BCRP) in lung cancer is correlated with development of multidrug resistance (MDR) and therefore leads to lower response to chemotherapy. ZM323881, a previously developed selective VEGFR-2 inhibitor, was found to have inhibitory effects on BCRP-mediated MDR in this investigation. ZM323881 significantly decreased the cytotoxic doses of mitoxantrone and SN-38 in BCRP-overexpressing NCI-H460/MX20 cells. Mechanistic studies revealed that ZM323881 effected by inhibiting BCRP-mediated drug efflux, leading to intracellular accumulation of BCRP substrates. No significant alteration in the expression levels and localization pattern of BCRP was observed when BCRP-overexpressing cells were exposed to ZM323881. Stimulated bell-shaped ATPase activities were observed. Molecular docking suggested that ZM323881 binds to the modulator site of BCRP and the binding pose is stable validated by 100ns molecular dynamic simulation. Overall, our results indicated that ZM323881 reversed BCRP-related MDR by inhibiting its efflux function. These findings might be useful in developing combination chemotherapy for MDR cancer treatment.

Trichosanatine alleviates oxidized low-density lipoprotein induced endothelial cells injury via inhibiting the LOX-1/p38 MAPK pathway

The LOX-1/p38 mitogen-activated protein kinase (MAPK) pathway has been proved to participate in the endothelial dysfunction in atherosclerosis. Trichosanatineis is an active compound isolated from the peel of Trichosanthes kirilowii. This study aims to determine whether trichosanatine prevents the oxidized low-density lipoprotein (ox-LDL)-induced insult through inhibition of the LOX-1/p38 MAPK pathway in HUVECs. HUVECs were treated with 150 mg/ml ox-LDL for 24 h to establish an ox-LDL-induced endothelial injury model. Cell viability, mitochondrial membrane potential (MMP), apoptosis, reactive oxygen species (ROS) level, LOX-1 and p38 MAPK expression level were measured. The results indicated that HUVECs were pretreated with either 100 mM trichosanatine or LOX-1 shRNA prior to exposure to ox-LDL for 24 h. Exposure of HUVECs to 150 mg/ml ox-LDL for 24 h significantly up-regulated the expression levels of LOX-1. The increased expression levels of LOX-1 were markedly attenuated by pretreatment with 100 mM trichosanatine. In addition, the ox-LDL-induced increase in phosphorylated (p) p38 MAPK expression was ameliorated by pretreatment with LOX-1 shRNA. Pretreatment of HUVECs with either trichosanatine or LOX-1 shRNA before exposure to ox-LDL significantly inhibited the ox-LDL-induced injuries, as evidenced by an increase in cell viability, a decrease in apoptotic cells, a ROS generation and a loss of MMP. In conclusion, we have demonstrated for the first time that the LOX-1/p38 MAPK pathway contributes to the ox-LDL-induced injury in HUVECs. Meanwhile, the trichosanatine protects the HUVECs against ox-LDL-induced injury at least in part by inhibiting the activated of LOX-1/p38 MAPK pathway.

Osimertinib (AZD9291), a Mutant-Selective EGFR Inhibitor, Reverses ABCB1-Mediated Drug Resistance in Cancer Cells

In recent years, tyrosine kinase inhibitors (TKIs) have been shown capable of inhibiting the ATP-binding cassette (ABC) transporter-mediated multidrug resistance (MDR). In this study, we determine whether osimertinib, a novel selective, irreversible EGFR (epidermal growth factor receptor) TKI, could reverse ABC transporter-mediated MDR. The results showed that, at non-toxic concentrations, osimertinib significantly sensitized both ABCB1-transfected and drug-selected cell lines to substrate anticancer drugs colchicine, paclitaxel, and vincristine. Osimertinib significantly increased the accumulation of [³H]-paclitaxel in ABCB1 overexpressing cells by blocking the efflux function of ABCB1 transporter. In contrast, no significant alteration in the expression levels and localization pattern of ABCB1 was observed when ABCB1 overexpressing cells were exposed to 0.3 µM osimertinib for 72 h. In addition, ATPase assay showed osimertinib stimulated ABCB1 ATPase activity. Molecular docking and molecular dynamic simulations showed osimertinib has strong and stable interactions at the transmembrane domain of human homology ABCB1. Taken together, our findings suggest that osimertinib, a clinically-approved third-generation EGFR TKI, can reverse ABCB1-mediated MDR, which supports the combination therapy with osimertinib and ABCB1 substrates may potentially be a novel therapeutic stategy in ABCB1-positive drug resistant cancers.