Virtual screening of National Cancer Institute database for claudin-4 inhibitors: Synthesis, biological evaluation, and molecular dynamics studies

Comprehensive Phytochemical Profile of Leaves, Stems and Fruits from Orthopterygium huaucui (A. Gray) Hemsl. and their Antioxidant Activities

Orthopterygium huaucui, commonly known as "Pate", is a medicinal shrub belonging to the Anacardiaceae family used locally to treat burns and stomach pains. Endemic to Peru, chemical studies on O. huaucui are limited. In this study, Ultra-High Performance Liquid Chromatography Quadrupole/Orbitrap Electrospray Ionization Tandem Mass Spectrometry (UHPLC Q/Orbitrap/ESI/MS/MS) was used to identify secondary metabolites in leaves, stems and fruits, and the antioxidant capacities of the different parts were compared. In addition, several compounds such as methyl gallate, gallic acid, kaempferol, quercetin, and quercetin 3-O-β-glucuronide were successfully isolated from the methanolic extract of the leaves of this species for the first time. Untargeted UHPLC Q/Orbitrap/ESI/MS/MS analysis tentatively identified seventy-six compounds in the different parts of the plant, showing that this species as an interesting source of flavonoids, procyanidins and tannins. The phenolic content in leaves and stems was 334.31±4.34 and 295.18±6.38 gallic acid equivalents/100 g dry plant, respectively, while that of fruits was lower (99.92±5.45 mg/100 g). Leaves had twice the flavonoid content than fruits (210.38±3.85 versus 87.42±3.85 quercetin equivalents/100 g). 2,2-Diphenyl-1-picrylhydrazyl (DPPH) results indicated high antioxidant activity in all parts, with stems and leaves showing IC50 of 12.8 μg/mL, and fruits showing less activity (IC50=38.6 μg/mL). The Oxygen Radical Absorbance Capacity (ORAC) test showed higher antioxidant values in the stems (467.82±21.17 μmol Trolox equivalents/100 g). This study provides valuable information on the chemistry of O. huaucui and highlights its antioxidant potential, especially in leaves and stems.

Purpurogallin carboxylic acid exhibits synergistic effects with 5‑fluorouracil on liver cancer cells in vitro by targeting ABCG2

Purpurogallin carboxylic acid (PCA) is a natural phenol compound derived from Macleaya microcarpa (Maxim.) Fedde, which exerts particular antioxidant and anti-inflammatory capacities. However, the effects and mechanisms of PCA on liver cancer cells remain unknown. Therefore, network pharmacology and computer virtual docking were used to identify the target-proteins of PCA. In addition, surface plasmon resonance, protease activity and rhodamine excretion assays were carried out to evaluate the effects of PCA on the activity of ATP binding cassette subfamily G member 2 (ABCG2). The synergistic effects of PCA and 5-fluorouracil (5-FU) on liver cancer cell proliferation, cell cycle arrest, colony formation and spheroid formation abilities in vitro were determined by Cell Counting Kit-8 (CCK-8) assay, flow cytometry, western blot analysis, colony formation and spheroid formation assays, respectively. ABCG2 was identified as a potential target of PCA, with a high docking score. The equilibrium dissociation constant of PCA for ABCG2 protein was 1.84 µM, while the median inhibitory concentration of this protein was 3.09 µM. In addition, the results demonstrated that PCA could significantly reduce the drug efflux capacity of liver cancer cells. CCK-8 assays revealed that liver cancer cell treatment with 10 µM PCA and 10 µM 5-FU exhibited the most potent synergistic effects on liver cancer cell proliferation at 48 h. Additionally, cell co-treatment with PCA and 5-FU also significantly attenuated the colony and spheroid formation abilities of liver cancer cells in vitro, while it promoted their arrest at the G1 phase of the cell cycle. Furthermore, ABCG2 silencing in liver cancer cells notably abrogated the synergistic effects of PCA and 5-FU. In conclusion, the present study demonstrated that PCA exhibited synergistic effects with 5-FU on liver cancer cells in vitro via targeting ABCG2. Therefore, PCA combined with 5-FU may be a potential strategy for liver cancer therapy.

K. H, Basavaraju P, Pasumarthi D, S. D. A, Soujanya P, Arnold Emeson I, Bodiga V, Pawar SC. Inhibition of Inducible Nitric Oxide Synthase (iNOS) by Andrographolide and In Vitro Evaluation of Its Antiproliferative and Proapoptotic Effects on Cervical Cancer

This work is aimed at investigating the expression levels of inducible nitric oxide synthase (iNOS) in cervical cancer and identifying a potential iNOS inhibitor. The data mining studies performed advocated iNOS to be a promising biomarker for cancer prognosis, as it is highly overexpressed in several malignant cancers. The elevated iNOS was found to be associated with poor survival and increased tumor aggressiveness in cervical cancer. Immunohistochemical and RT-PCR investigations of iNOS showed significant upregulation of endogenous iNOS expression in the cervical tumor samples, thus making iNOS a potent target for decreasing tumor inflammation and aggressiveness. Andrographolide, a plant-derived diterpenoid lactone, is widely reported to be effective against infections and inflammation, causing no adverse side effects on humans. In the current study, we investigated the effect of andrographolide on the prognostic value of iNOS expression in cervical cancer, which has not been reported previously. The binding efficacy of andrographolide was analyzed by performing molecular docking and molecular dynamic simulations. Multiple parameters were used to analyze the simulation trajectory, like root mean square deviation (RMSD), torsional degree of freedom, protein-root mean square fluctuations (P-RMSF), ligand RMSF, total number of intramolecular hydrogen bonds, secondary structure elements (SSE) of the protein, and protein complex with the time-dependent functions of MDS. Ligand-protein interactions revealed binding efficacy of andrographolide with tryptophan amino acid of iNOS protein. Cancer cell proliferation, cell migration, cell cycle analysis, and apoptosis-mediated cell death were assessed in vitro, post iNOS inhibition induced by andrographolide treatment (demonstrated by Western blot). Results. Andrographolide exhibited cytotoxicity by inhibiting the in vitro proliferation of cervical cancer cells and also abrogated the cancer cell migration. A significant increase in apoptosis was observed with increasing andrographolide concentration, and it also induced cell cycle arrest at G1-S phase transition. Our results substantiate that andrographolide significantly inhibits iNOS expression and exhibits antiproliferative and proapoptotic effects on cervical cancer cells.

Screening approaches against claudin-4 focusing on therapeutics through molecular docking and the analysis of their relative dynamics: a theoretical approach

Claudin-4 (CLDN4) is a class of transmembrane protein in the family of tight junction (TJ) proteins. Overexpression of CLDN4 is reported in the case of ovarian cancer and epithelial malignancies. The current study is focused on the identification of lead compounds for CLDN4 adopting the structure-based drug design method. The Schrodinger glide is used as a molecular docking tool for the initial docking of CLDN4 with Asinex Database by performing high throughput virtual screening, top hits were identified. Then, compounds BDF 33196188 and BDE 30874918 were identified by molecular docking based on binding energy in the active site of CLDN4. Subsequently, critical residues were identified such as Asp146 and Arg158 with the least binding energy from Extra Precision method. Further, molecular dynamics simulations of claudin-4 protein were used for the optimization of best ligands with claudin-4 in a dynamic system. Molecular docking and molecular dynamics simulations predicted critically important residues ASP146 and ARG158 involved in claudin-4 binding. The hits retrieved from screening were docked into protein by relevant procedures including HTVS, SP, and XP. Finally, two molecules were identified as potential claudin-4 inhibitors. The two ligands BDF 33196188 and BDE 30874918 are suggested as potential inhibitors for CLDN4. In summary, our computational strategy established novel leads against CLDN4 from Asinex Database and recommended as anti-cancer agents.

Expression profiles of long noncoding RNAs in retinopathy of prematurity

Long noncoding RNA (lncRNA) regulates the proliferation and migration of human retinal endothelial cells, as well as retinal neovascularization in diabetic retinopathy. Based on similarities between the pathogenesis of retinopathy of prematurity (ROP) and diabetic retinopathy, lncRNA may also play a role in ROP. Seven-day-old mice were administered 75 ± 2% oxygen for 5 days and normoxic air for another 5 days to establish a ROP model. Expression of lncRNA and mRNA in the retinal tissue of mice was detected by high-throughput sequencing technology, and biological functions of the resulted differentially expressed RNAs were evaluated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. The results showed that compared with the control group, 57 lncRNAs were differentially expressed, including 43 upregulated and 14 downregulated, in the retinal tissue of ROP mice. Compared with control mice, 42 mRNAs were differentially expressed in the retinal tissue of ROP mice, including 24 upregulated and 18 downregulated mRNAs. Differentially expressed genes were involved in ocular development and related metabolic pathways. The differentially expressed lncRNAs may regulate ROP in mice via microRNAs and multiple signaling pathways. Our results revealed that these differentially expressed lncRNAs may be therapeutic targets for ROP treatment. This study was approved by the Medical Ethics Committee of Shengjing Hospital of China Medical University on February 25, 2016 (approval No. 2016PS074K).