0000000000125316
AUTHOR
Tolga Eichhorn
Molecular interaction of artemisinin with translationally controlled tumor protein (TCTP) of Plasmodium falciparum
Malaria causes millions of death cases per year. Since Plasmodium falciparum rapidly develops drug resistance, it is of high importance to investigate potential drug targets which may lead to novel rational therapy approaches. Here we report on the interaction of translationally controlled tumor protein of P. falciparum (PfTCTP) with the anti-malarial drug artemisinin. Furthermore, we investigated the crystal structure of PfTCTP. Using mass spectrometry, bioinformatic approaches and surface plasmon resonance spectroscopy, we identified novel binding sites of artemisinin which are in direct neighborhood to amino acids 19-46, 108-134 and 140-163. The regions covered by these residues are know…
Effects of Scrophularia ningpoensis Hemsl. on Inhibition of Proliferation, Apoptosis Induction and NF-κB Signaling of Immortalized and Cancer Cell Lines
Scrophularia ningpoensis has been used in China for centuries as a herbal tea to treat various diseases. Based on the numerous animal studies on its pharmaceutical effects and the long time clinical experiences, we studied the molecular and cellular mechanism underlying the bioactivity of aqueous extract of Scrophularia and its isolated compounds. Seven isolated compounds, unlike Scrophularia extract, failed to induce cytotoxicity on HaCaT cells, but their combination improved the effect of extract. Tumor cell line selectivity was not observed, when we studied its cytotoxic effect on melanoma cell lines. The apoptotic and anti-inflammatory effects of Scrophularia extract have been demonstra…
Utilizing inherent fluorescence of therapeutics to analyze real-time uptake and multi-parametric effector kinetics.
Abstract The precise detection of pharmaceutical drug uptake and knowledge of a drug’s efficacy at the single-cell level is crucial for understanding a compound’s performance. Many pharmaceutical drugs, like the model substances Doxorubicin, Mitoxantrone or Irinotecan, have a distinctive natural fluorescence that can be readily exploited for research purposes. Utilizing this respective natural fluorescence, we propose a method analyzing simultaneously in real-time the efficiency, effects and the associated kinetics of compound-uptake and efflux in mammalian cells by flow cytometry. We show that real-time flow cytometric quantification of compound-uptake is reliably measured and that analyzi…
Molecular Determinants of the Response of Tumor Cells to Boswellic Acids
Frankincense (Boswellia serrata, B. carterii) is used as traditional remedy to treat inflammatory diseases. The molecular effects of the active ingredients, the boswellic acids, on the immune system have previously been studied and verified in several clinical studies. Boswellic acids also inhibit cancer cell growth in vitro and in vivo. The molecular basis of the cytotoxicity of boswellic acids is, however, not fully understood as yet. By mRNA-based microarray, COMPARE, and hierarchical cluster analyses, we identified a panel of genes from diverse functional groups, which were significantly associated with sensitivity or resistance of a- or b-boswellic acids, such as transcription factors,…
Factors determining sensitivity or resistance of tumor cell lines towards artesunate.
Clinical oncology is still challenged by the development of drug resistance of tumors that result in poor prognosis for patients. There is an urgent necessity to understand the molecular mechanisms of resistance and to develop novel therapy strategies. Artesunate (ART) is an anti-malarial drug, which also exerts profound cytotoxic activity towards cancer cells. We first applied a gene-hunting approach using cluster and COMPARE analyses of microarray-based transcriptome-wide mRNA expression profiles. Among the genes identified by this approach were genes from diverse functional groups such as structural constituents of ribosomes (RPL6, RPL7, RPS12, RPS15A), kinases (CABC1, CCT2, RPL41), tran…
Abstract 4662: Shikonin causes cancer cell death by inducing mitochondrial dysfunction
Abstract Shikonin, a naturally occurring napthoquinone, has been used in herbal formulations for the treatment of several inflammatory diseases in Traditional Chinese Medicine since decades. In recent studies, shikonin revealed remarkable anticancer activities and thereby is a promising candidate for cancer chemotherapy. However, the underlying cellular mechanisms and targets of shikonin are still unknown. Here, we showed that shikonin indeed exhibits strong cytotoxic effects on a panel of 15 different cancer cell lines also containing multi-drug resistant cells. The strongest effects were obtained on U937 leukemia cells. To better understand the underlying mechanisms, we performed a whole …
Differential interactions of the broad spectrum drugs artemisinin, dihydroartemisinin and artesunate with serum albumin
Artemisinin is a drug, widely used in malaria treatment. As the binding affinity of artemisinin and its derivatives dihydroartemisinin and artesunate to blood serum proteins might influence the effectiveness of the drug, binding of artemisinin and derivatives to serum albumin was studied under near physiological conditions. Binding kinetics indicate a simple, single-step association process for all artemisinin derivatives. The determined changes in enthalpy and entropy upon drug binding clearly indicate that hydrophobic forces are most important for artemisinin and dihydroartemisinin binding, whereas binding of artesunate is governed by both hydrophilic and hydrophobic forces. Key residues,…
Abstract 1993: Fishing for artemisinin-interacting proteins from human nasopharyngeal cancer cells
Abstract Determining cellular target molecules of drugs by chemical proteomic techniques is complex and tedious. Most approaches rely on activity-based probe profiling and compound-centric chemical proteomics. The antimalarial artemisinin also exerts profound anti-cancer activity, but the mechanisms of action are incompletely understood. In the present study, we have identified artemisinin-interacting target proteins from human nasopharyngeal carcinoma cell line CNE1. Thereby, our approach overcomes usual problems in traditional fishing procedures, because the drug was attached to a polystyrene surface without further chemical modification. Using mass spectrometry we have identified 20 prot…
Cytotoxicity, anti-angiogenic, apoptotic effects and transcript profiling of a naturally occurring naphthyl butenone, guieranone A
Abstract Background Malignant diseases are responsible of approximately 13% of all deaths each year in the world. Natural products represent a valuable source for the development of novel anticancer drugs. The present study was aimed at evaluating the cytotoxicity of a naphtyl butanone isolated from the leaves of Guiera senegalensis, guieranone A (GA). Results The results indicated that GA was active on 91.67% of the 12 tested cancer cell lines, the IC50 values below 4 μg/ml being recorded on 83.33% of them. In addition, the IC50 values obtained on human lymphoblastic leukemia CCRF-CEM (0.73 μg/ml) and its resistant subline CEM/ADR5000 (1.01 μg/ml) and on lung adenocarcinoma A549 (0.72 μg/m…
P-glycoprotein and its inhibition in tumors by phytochemicals derived from Chinese herbs
P-glycoprotein belongs to the family of ATP-binding cassette (ABC) transporters. It functions in cellular detoxification, pumping a wide range of xenobiotic compounds, including anticancer drugs out of the cell. In cancerous cells, P-glycoprotein confers resistance to a broad spectrum of anticancer agents, a phenomenon termed multidrug resistance. An attractive strategy for overcoming multidrug resistance is to block the transport function of P-glycoprotein and thus increase intracellular concentrations of anticancer drugs to lethal levels. Efforts to identify P-glycoprotein inhibitors have led to numerous candidates, none of which have passed clinical trials with cancer patients due to the…
Abstract 2679: Virtual screening of small molecule inhibitors towards the tumor suppressor p53 to overcome radioresistance of nasopharyngeal carcinoma cells
Abstract The tumor suppressor p53 belongs to the most frequently mutated genes in cancer, including nasopharyngeal carcinoma (NPC). p53 is over-expressed in NPC, but the mutation rate is lower than in other tumor types. Therefore, it can be hypothesized that p53 might be involved in repair of DNA-damage after radiotherapy and causes recrudescence. Hence, the aim of the present investigation was to identify small molecule inhibitors for p53 to inhibit DNA repair after ionizing radiation of NPC. Approximately 260.000 2D-structures from NCI database were downloaded and different tautomers and charged stages between pH 5 and 9 were calculated for each compound. A total number of 906.587 drugs i…
Inhibition in vivo of the activity of botulinum neurotoxin A by small molecules selected by virtual screening
To search for small molecular size inhibitors of botulinum neurotoxin A (BoNT/A) endopeptidase activity, we have screened the NCI library containing about 1 million structures against the substrate binding pocket of BoNT/A. Virtual screening (VS) was performed with the software Glide (Grid-based ligand docking energetics) and the findings were confirmed by AutoDock. Ten compounds were found that had favorable energetic and glide criteria and 5 of these compounds were selected for their ability to protect mice in vivo against a lethal dose of BoNT/A. Each compound was incubated at different molar excesses with a lethal dose of the toxin and then the mixture injected intravenously into mice. …
Bioinformatic and experimental fishing for artemisinin-interacting proteins from human nasopharyngeal cancer cells.
Determining interacting cellular partners of drugs by chemical proteomic techniques is complex and tedious. Most approaches rely on activity-based probe profiling and compound-centric chemical proteomics. The anti-malarial artemisinin also exerts profound anti-cancer activity, but the mechanisms of action are incompletely understood. In the present investigation, we present a novel approach to identify artemisinin-interacting target proteins. Our approach overcomes usual problems in traditional fishing procedures, because the drug was attached to a surface without further chemical modification. The proteins identified effect among others, cell cycle arrest, apoptosis, inhibition of angiogen…
Pharmacogenomic determination of genes associated with sensitivity or resistance of tumor cells to curcumin and curcumin derivatives
Curcuma longa L. has long been used as a medicinal plant in traditional Chinese medicine against abdominal disorders. Its active constituent curcumin has anti-inflammatory, chemopreventive and cytotoxic properties. In the present investigation, we have analyzed the cytotoxic activity of curcumin and four derivatives. Among these compounds, ethoxycurcumintrithiadiazolaminomethylcarbonate was the most cytotoxic one. The curcumin-type compounds were not cross-resistant to standard anticancer drugs and were not involved in ATP-binding cassette transporter-mediated multidrug resistance. A combined approach of messenger RNA-based microarray profiling, COMPARE analyses and signaling pathway analys…