Combinatory cytotoxic effects produced by E1B-55kDa-deleted adenoviruses and chemotherapeutic agents are dependent on the agents in esophageal carcinoma

We examined possible combinatory antitumor effects of replication-competent type 5 adenoviruses (Ad) lacking E1B-55kDa molecules (Ad-delE1B55) and chemotherapeutic agents in nine human esophageal carcinoma cells. Ad-delE1B55 produced cytotoxic effects on all the carcinoma cells and the cytotoxicity is not directly linked with the p53 status of the tumors or with the infectivity to respective tumors. A combinatory treatment with Ad-delE1B55 and an anticancer agent, 5-fluorouracil (5-FU), mitomycin C or etoposide, produced greater cytotoxic effects than that with either the Ad or the agent. Administration of 5-FU could minimally inhibit the viral replication and a simultaneous treatment with the Ad and 5-FU achieved better cytotoxicity than sequential treatments. We also confirmed the antitumor effects by the combination of Ad-delE1B55 with 5-FU in vivo. Cisplatin, however, did not achieve the combinatory effects in most of the cells tested. These data indicate that the Ad-delE1B55 produce combinatory antitumor effects with a chemotherapeutic agent irrespective of the administration schedule, but the effects depend on an agent in esophageal carcinoma

High efficiency of alphaviral gene transfer in combination with 5-fluorouracil in a mouse mammary tumor model

Copyright: Copyright 2014 Elsevier B.V., All rights reserved.Background: The combination of virotherapy and chemotherapy may enable efficient tumor regression that would be unachievable using either therapy alone. In this study, we investigated the efficiency of transgene delivery and the cytotoxic effects of alphaviral vector in combination with 5-fluorouracil (5-FU) in a mouse mammary tumor model (4 T1).Methods: Replication-deficient Semliki Forest virus (SFV) vectors carrying genes encoding fluorescent proteins were used to infect 4 T1 cell cultures treated with different doses of 5-FU. The efficiency of infection was monitored via fluorescence microscopy and quantified by fluorometry. The cytotoxicity of the combined treatment with 5-FU and alphaviral vector was measured using an MTT-based cell viability assay. In vivo experiments were performed in a subcutaneous 4 T1 mouse mammary tumor model with different 5-FU doses and an SFV vector encoding firefly luciferase.Results: Infection of 4 T1 cells with SFV prior to 5-FU treatment did not produce a synergistic anti-proliferative effect. An alternative treatment strategy, in which 5-FU was used prior to virus infection, strongly inhibited SFV expression. Nevertheless, in vivo experiments showed a significant enhancement in SFV-driven transgene (luciferase) expression upon intratumoral and intraperitoneal vector administration in 4 T1 tumor-bearing mice pretreated with 5-FU: here, we observed a positive correlation between 5-FU dose and the level of luciferase expression.Conclusions: Although 5-FU inhibited SFV-mediated transgene expression in 4 T1 cells in vitro, application of the drug in a mouse model revealed a significant enhancement of intratumoral transgene synthesis compared with 5-FU untreated mice. These results may have implications for efficient transgene delivery and the development of potent cancer treatment strategies using alphaviral vectors and 5-FU.publishersversionPeer reviewe

Rapid selection of cyclic peptides that reduce alpha-synuclein toxicity in yeast and animal models

Phage display has demonstrated the utility of cyclic peptides as general protein ligands but cannot access proteins inside eukaryotic cells. Expanding a new chemical genetics tool, we describe the first expressed library of head-to-tail cyclic peptides in yeast (Saccharomyces cerevisiae). We applied the library to selections in a yeast model of alpha-synuclein toxicity that recapitulates much of the cellular pathology of Parkinson's disease. From a pool of 5 million transformants, we isolated two related cyclic peptide constructs that specifically reduced the toxicity of human alpha-synuclein. These expressed cyclic peptide constructs also prevented dopaminergic neuron loss in an established Caenorhabditis elegans Parkinson's model. This work highlights the speed and efficiency of using libraries of expressed cyclic peptides for forward chemical genetics in cellular models of human disease

Adenosine A1 receptor: Functional receptor-receptor interactions in the brain

Over the past decade, many lines of investigation have shown that receptor-mediated signaling exhibits greater diversity than previously appreciated. Signal diversity arises from numerous factors, which include the formation of receptor dimers and interplay between different receptors. Using adenosine A1 receptors as a paradigm of G protein-coupled receptors, this review focuses on how receptor-receptor interactions may contribute to regulation of the synaptic transmission within the central nervous system. The interactions with metabotropic dopamine, adenosine A2A, A3, neuropeptide Y, and purinergic P2Y1 receptors will be described in the first part. The second part deals with interactions between A1Rs and ionotropic receptors, especially GABAA, NMDA, and P2X receptors as well as ATP-sensitive K+ channels. Finally, the review will discuss new approaches towards treating neurological disorders

Chem. Biol.

The active-site hexapeptides of glutaredoxin (Grx), thioredoxin (Trx), protein disulfide isomerase (PDI), and thioredoxin- reductase (Trr) containing the common motif Cys-Xaa-Yaa-Cys were conformationally restricted by backbone cyclization, and their redox potentials were found to increase in the rank order of Trr < Grx < Trx < PDI peptide, with E'(o) values ranging between -204 mV and -130 mV. In each peptide the thiol pK(a) of one Cys residue was found to be lower than the other (e.g., 7.3 against 9.6 in the PDI peptide). Both the yield and rate of refolding of reduced RNase A in the presence of the bis(cysteinyl)peptides increased with the oxidizing character of the cyclic compounds. These results show that small peptides can function as adjuvants for the in vitro oxidative folding of proteins

Redox-active cyclic bis(cysteinyl)peptides as catalysts for in vitro oxidative protein folding

The active-site hexapeptides of glutaredoxin (Grx), thioredoxin (Trx), protein disulfide isomerase (PDI), and thioredoxin- reductase (Trr) containing the common motif Cys-Xaa-Yaa-Cys were conformationally restricted by backbone cyclization, and their redox potentials were found to increase in the rank order of Trr < Grx < Trx < PDI peptide, with E'(o) values ranging between -204 mV and -130 mV. In each peptide the thiol pK(a) of one Cys residue was found to be lower than the other (e.g., 7.3 against 9.6 in the PDI peptide). Both the yield and rate of refolding of reduced RNase A in the presence of the bis(cysteinyl)peptides increased with the oxidizing character of the cyclic compounds. These results show that small peptides can function as adjuvants for the in vitro oxidative folding of proteins

Eur. J. Org. Chem.

The octapeptide [134-141] related to the active-site fragment of thioredoxin reductase, in which three residues outside the characteristic Cys-Xaa-Yaa-Cys motif of thiol/disulfide oxidoreductases were replaced by lysines, was head-to-tail- cyclized by using the suitably functionalized (4- aminomethyl)phenylazobenzoic acid (AMPB). The resulting monocyclic and disulfide-bridged bicyclic compounds underwent light-induced cis/trans isomerization in a fully reversible manner, with well-defined conformational transitions as a result of the strong differences in the molecular geometries of the trans and cis-azobenzene units. Correspondingly, the trans and cis forms of the cyclic bis(cysteinyl)-AMPB peptide were characterized by significantly differentiated redox potentials, which were exploited to catalyze the oxidative refolding of reduced RNase A with distinct efficiencies. The experimental results showed that the incorporation of the azobenzene moiety into conformationally restricted bis(cysteinyl) peptide systems provided folding adjuvants that photocontrolled the rates of oxidative protein folding