Multiorgan metastasis of human HER-2⁺ breast cancer in Rag2⁻/⁻;Il2rg⁻/⁻ mice and treatment with PI3K inhibitor

In vivo studies of the metastatic process are severely hampered by the fact that most human tumor cell lines derived from highly metastatic tumors fail to consistently metastasize in immunodeficient mice like nude mice. We describe a model system based on a highly immunodeficient double knockout mouse, Rag2?/?;Il2rg?/?, which lacks T, B and NK cell activity. In this model human metastatic HER-2? breast cancer cells displayed their full multiorgan metastatic potential, without the need for selections or additional manipulations of the system. Human HER-2? breast cancer cell lines MDA-MB-453 and BT-474 injected into Rag2?/?;Il2rg?/? mice faithfully reproduced human cancer dissemination, with multiple metastatic sites that included lungs, bones, brain, liver, ovaries, and others. Multiorgan metastatic spread was obtained both from local tumors, growing orthotopically or subcutaneously, and from cells injected intravenously. The problem of brain recurrencies is acutely felt in HER-2? breast cancer, because monoclonal antibodies against HER-2 penetrate poorly the blood-brain barrier. We studied whether a novel oral small molecule inhibitor of downstream PI3K, selected for its penetration of the blood-brain barrier, could affect multiorgan metastatic spread in Rag2?/?; Il2rg?/? mice. NVP-BKM120 effectively controlled metastatic growth in multiple organs, and resulted in a significant proportion of mice free from brain and bone metastases. Human HER-2? human breast cancer cells in Rag2?/?;Il2rg?/? mice faithfully reproduced the multiorgan metastatic pattern observed in patients, thus allowing the investigation of metastatic mechanisms and the preclinical study of novel antimetastatic agents.     

Phytochemical analysis and antioxidant activity of Tamarix africana,Arthrocnemum macrostachyum and Suaeda fruticosa,three halophyte species from Algeria

Abstract

Extracts and fractions using six solvents of increasing polarities from Northwest Algeria (Tamarix africana, Arthrocnemum macrostachyum and Suaeda fruticosa) were studied for phytochemical analysis and in vitro antioxidant properties. Methanol and water fractions were found to be the more suitable solvents used for extraction of polyphenolic compounds. Aqueous leaf fraction of T. africana showed the highest content of phenolics (61.06?±?0.40?mg GAE/g DW) and condensed tannins (118.43?±?11.79?mg CE/g DW). Dichloromethane stem fraction of T. africana had the highest 2,2-diphenyl-1-picrylhydrazil radical scavenging ability (0.34?±?0.00?mg/ml). Methanol leaf fraction of the same plant exhibited the highest antioxidant power against the inhibition of β-carotene bleaching, while the maximum total antioxidant capacity was recorded in the leaf extract of S. fruticosa. Phenolic content was not influenced by the species but very affected by the extraction solvent, while antioxidant activities were not influenced by these two parameters. High-performance liquid chromatography with a diode-array detector analysis of methanol and aqueous leaf fractions of T. africana revealed the presence of six phenolic acids; chlorogenic and gallic acids were predominant and 10 flavonoid compounds among which rutin and quercetin-3-O-arabonoside were the major constituents. These findings suggest that these species may be considered as an interesting source of antioxidants.     

Protein and m-RNA expression of farnesyl-transferases,RhoA and RhoB in rat liver hepatocytes: action of perillyl alcohol and vitamin A <Emphasis Type="BoldItalic">in vivo</Emphasis>.

Summary We analysed the action, in rats in vivo, of the protein isoprenylation inhibitor perillyl alcohol (POH) and that of vitamin A, alone or in association, on m-RNA and protein expression of farnesyltransferases (FTases α and β subunits) and their protein substrates RhoA and RhoB, in isolated hepatocytes. Combined administration of POH and vitamin A induced a sharp decrease in FTase α protein after 96 h, suggesting an involvement not only of farnesyltransferases but also of geranylgeranyltransferases, which share the FTase α protein. FTase β protein did not decrease. POH plus vitamin A, in contrast with POH or vitamin A alone, induced a decrease in RhoB protein, probably because of different cleavages. No modification was observed in RhoA protein. Vitamin A alone increased RhoB m-RNA and protein expression. As one of the functions of RhoB is cell polarisation, these data support our previous hypothesis of a polarised transport of vitamin A from hepatocytes to hepatic stellate cells. As the behaviours of m-RNAs and proteins in this study were often different, cytoplasmic metabolic pathways must be considered for the parameters studied. The behaviour of Rho B, which is thought to have an antioncogene function, is discussed in view of its isoprenylated forms in the membranes. These preliminary findings stress the need, when studying the association of two isoprenoids in cancer therapy, to consider normal as well as tumour-bearing animals.     

Investigation of the role of ubiquinone in rat liver subcellular compartments

The role of ubiquinone in the Golgi apparatus is still unknown, even if it might be considered as a lipid marker of the Golgi compartment because of its high content in these subcellular fractions. In vivo modulation of ubiquinone with ethanol and in vitro pentane extraction show that ubiquinone is not required either for NADH-ferricyanide reductase, acetaldehyde dehydrogenase activity, or Ca2+ and Mg2+ stimulated ATPases. Since ubiquinone does not seem to be involved in these enzymic activities in Golgi compartments, other possible functions are discussed, related to a role in membrane fluidity or as a barrier to the propagation of free radicals.