Glycyrrhizin Exerts Antioxidative Effects in H5N1 Influenza A Virus-Infected Cells and Inhibits Virus Replication and Pro-Inflammatory Gene Expression

Glycyrrhizin is known to exert antiviral and anti-inflammatory effects. Here, the effects of an approved parenteral glycyrrhizin preparation (Stronger Neo-Minophafen C) were investigated on highly pathogenic influenza A H5N1 virus replication, H5N1-induced apoptosis, and H5N1-induced pro-inflammatory responses in lung epithelial (A549) cells. Therapeutic glycyrrhizin concentrations substantially inhibited H5N1-induced expression of the pro-inflammatory molecules CXCL10, interleukin 6, CCL2, and CCL5 (effective glycyrrhizin concentrations 25 to 50 µg/ml) but interfered with H5N1 replication and H5N1-induced apoptosis to a lesser extent (effective glycyrrhizin concentrations 100 µg/ml or higher). Glycyrrhizin also diminished monocyte migration towards supernatants of H5N1-infected A549 cells. The mechanism by which glycyrrhizin interferes with H5N1 replication and H5N1-induced pro-inflammatory gene expression includes inhibition of H5N1-induced formation of reactive oxygen species and (in turn) reduced activation of NFκB, JNK, and p38, redox-sensitive signalling events known to be relevant for influenza A virus replication. Therefore, glycyrrhizin may complement the arsenal of potential drugs for the treatment of H5N1 disease

Differential effects of the oncogenic BRAF inhibitor PLX4032 (vemurafenib) and its progenitor PLX4720 on ABCB1 function

PURPOSE: The clinically approved oncogenic BRAF inhibitor PLX4032 (vemurafenib) was shown to be a substrate of the ATP-binding cassette (ABC) transporter ABCB1. Here, we compared PLX4032 and its structurally closely related precursor compound PLX4720 for their interference with ABCB1 and the ABCB1-mediated compound transport using docking and cell culture experiments. METHODS: For the docking study of PLX4032 and PLX4720 with ABCB1, we analysed binding of both compounds to mouse Abcb1a and to human ABCB1 using a homology model of human ABCB1 based on the 3D structure of Abcb1a. Naturally ABCB1 expressing cells including V600E BRAF-mutated and BRAF wild-type melanoma cells and cells transduced with a lentiviral vector encoding for ABCB1 were used as cell culture models. ABCB1 expression and function were studied by the use of fluorescent and cytotoxic ABCB1 substrates in combination with ABCB1 inhibitors. RESULTS: Docking experiments predicted PLX4032 to interact stronger with ABCB1 than PLX4720. Experimental studies using different cellular models and structurally different ABCB1 substrates confirmed that PLX4032 interfered stronger with ABCB1 function than PLX4720. For example, PLX4032 (20μM) induced a 4-fold enhanced rhodamine 123 accumulation compared to PLX4720 (20μM) in ABCB1-transduced UKF-NB-3 cells and reduced the IC50 for the cytotoxic ABCB1 substrate vincristine in this model by 21-fold in contrast to a 9-fold decrease induced by PLX4720. CONCLUSIONS: PLX4032 exerted stronger effects on ABCB1-mediated drug transport than PLX4720. This indicates that small changes in a molecule can substantially modify its interaction with ABCB1, a promiscuous transporter that transports structurally different compounds

Inhibition of apoptosis prevents West Nile virus induced cell death

We found that WNV infection induces cell death in the brain-derived tumour cell line T98G by apoptosis under involvement of constituents of the extrinsic as well as the intrinsic apoptotic pathways. Our results illuminate the molecular mechanism of WNV-induced neural cell death

Increased HRD score in cisplatin resistant penile cancer cells

Penile cancer is a rare disease in demand for new therapeutic options. Frequently used combination chemotherapy with 5 fluorouracil (5-FU) and cisplatin (CDDP) in patients with metastatic penile cancer mostly results in the development of acquired drug resistance. Availability of cell culture models with acquired resistance against standard therapy could help to understand molecular mechanisms underlying chemotherapy resistance and to identify candidate treatments for an efficient second line therapy. We generated a cell line from a humanpapilloma virus (HPV) negative penile squamous cell carcinoma (UKF-PEC-1). This cell line was subject to chronic exposure to chemotherapy with CDDP and / or 5-FU to induce acquired resistance in the newly established chemo-resistant sublines (PEC-1 CDDP , adapted to 2500 ng/ml CDDP; UKF-PEC-1 5-FU , adapted to 500 ng/ml 5- FU; UKF-PEC1 CDDP / 5-FU , adapted to 2500 ng/ml CDDP and 500 ng/ml 5 -FU). Afterwards cell line pellets were formalin-fixed, paraffin embedded and subject to sequencing as well as testing for homologous recombination deficiency (HRD). Additionally, exemplary immunohistochemical stainings for p53 and gammaH2AX were applied for verification purposes. Finally, UKF-PEC-1 CDDP , UKF-PEC-1 5-FU , UKF-PEC1 CDDP / 5-FU , and UKF-PEC-3 (an alternative penis cancer cell line) were tested for sensitivity to paclitaxel, docetaxel, olaparib, and rucaparib. The chemo-resistant sublines differed in their mutational landscapes. UKF-PEC-1 CDDP was characterized by an increased HRD score, which is supposed to be associated with increased PARP inhibitor and immune checkpoint inhibitor sensitivity in cancer. However, UKF-PEC-1 CDDP did not display sensitivity to PARP inhibitors. [Abstract copyright: © 2022. The Author(s).

Effects of the histone deacetylase inhibitor valproic acid on Notch signalling in human neuroblastoma cells

Neuroblastoma (NB), a sympathetically derived childhood tumour, shows characteristics of neuronal precursor cells, suggesting a halted differentiation process. We have previously shown that the Notch signalling cascade, a key player during normal neurogenesis, also might be involved in NB differentiation. Valproic acid (VPA), a well-tolerated antiepileptic drug, has been shown to induce differentiation and cell death of NB cells, possibly associated with its recently described HDAC inhibiting activity. Stimulation of NB cells with VPA led to increased cell death and phenotypic changes associated with differentiation, that is, neurite extension and upregulation of neuronal markers. VPA treatment also led to an activated Notch signalling cascade as shown by increased levels of intracellular Notch-1 and Hes-1, mimicking the initial phase of induced differentiation. These results reinforce that VPA potentially could be used in differentiation therapy of NB and that the effects in part could be a consequence of interference with the Notch signalling cascade

Miyabeacin: A new cyclodimer presents a potential role for willow in cancer therapy

Willow (Salix spp.) is well known as a source of medicinal compounds, the most famous being salicin, the progenitor of aspirin. Here we describe the isolation, structure determination, and anti-cancer activity of a cyclodimeric salicinoid (miyabeacin) from S. miyabeana and S. dasyclados. We also show that the capability to produce such dimers is a heritable trait and how variation in structures of natural miyabeacin analogues is derived via cross-over Diels-Alder reactions from pools of ortho-quinol precursors. These transient ortho-quinols have a role in the, as yet uncharacterised, biosynthetic pathways around salicortin, the major salicinoid of many willow genotypes

Exploring Protein-Protein Interactions as Drug Targets for Anti-cancer Therapy with In Silico Workflows

We describe a computational protocol to aid the design of small molecule and peptide drugs that target protein-protein interactions, particularly for anti-cancer therapy. To achieve this goal, we explore multiple strategies, including finding binding hot spots, incorporating chemical similarity and bioactivity data, and sampling similar binding sites from homologous protein complexes. We demonstrate how to combine existing interdisciplinary resources with examples of semi-automated workflows. Finally, we discuss several major problems, including the occurrence of drug-resistant mutations, drug promiscuity, and the design of dual-effect inhibitors.Fil: Goncearenco, Alexander. National Institutes of Health; Estados UnidosFil: Li, Minghui. Soochow University; China. National Institutes of Health; Estados UnidosFil: Simonetti, Franco Lucio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Shoemaker, Benjamin A. National Institutes of Health; Estados UnidosFil: Panchenko, Anna R. National Institutes of Health; Estados Unido

Thiourea and Guanidine Compounds and their Iridium Complexes in Drug-Resistant Cancer Cell Lines: Structure-Activity Relationships and Direct Luminescent Imaging

Thiourea and guanidine units are found in nature, medicine, and materials. Their continued exploration in applications as diverse as cancer therapy, sensors, and electronics means that their toxicity is an important consideration. We have systematically synthesised a set of thiourea compounds and their guanidine analogues, and elucidated structure-activity relationships in terms of cellular toxicity in three ovarian cancer cell lines and their cisplatin-resistant sub-lines. We have been able to use the intrinsic luminescence of iridium complexes to visualise the effect of both structure alteration and cellular resistance mechanisms. These findings provide starting points for the development of new drugs and consideration of safety issues for novel thiourea- and guanidine-based materials

Microwave-assisted synthesis of highly crystalline, multifunctional iron oxide nanocomposites for imaging applications

We report a reproducible single-step, microwave-assisted approach for the preparation of multifunctional magnetic nanocomposites comprising superparamagnetic iron oxide (Fe3O4) cores, a polyelectrolyte stabilizer and an organic dye with no requirement for post-processing. The stabilisers poly(sodium 4-styrenesulfonate) (PSSS) and sodium polyphosphate (SPP) have been thoroughly investigated and from analysis using electron microscopy, dynamic light scattering measurements, magnetic hysteresis and magnetic resonance (MR) imaging, we show that the higher degree of Fe3O4 nanoparticle crystallinity achieved with the PSSS stabiliser leads to enhanced magnetic behaviour and thus better contrast agent relaxivity compared to the less crystalline, poorly defined particles obtained when SPP is employed as a stabiliser. We also demonstrate the potential for obtaining a multifunctional magnetic-fluorescent nanocomposite using our microwave-assisted synthesis. In this manner, we demonstrate the intimate link between synthetic methodology (microwave heating with a polyelectrolyte stabilizer) and the resulting properties (particle size, shape, and magnetism) and how this underpins the functionality of the resulting nanocomposites as agents for biomedical imaging