Natural products are the future of anticancer therapy: Preclinical and clinical advancements of Viscum album phytometabolites.

Cancer is a multifaceted and genomically complex disease. Research over the years has gradually provided a near complete resolution of cancer landscape and it is now known that genetic/epigenetic mutations, inactivation of tumor suppressors, Overexpression of oncogenes, spatio-temporally dysregulated intracellular signaling cascades, epithelial to mesenchymal transition (EMT), metastasis and loss of apoptosis are some of the most extensively studied biological mechanisms that underpin cancer development and progression. Increasingly it is being realized that current therapeutic interventions are becoming ineffective because of tumor heterogeneity and rapidly developing resistance against drugs. Considerable biological activities exerted by bioactive ingredients isolated from natural sources have revolutionized the field of natural product chemistry and rapid developments in preclinical studies are encouraging. Viscum album has emerged as a deeply studied natural source with substantial and multifaceted biological activities. In this review we have attempted to provide recent breakthroughs in existing scientific literature with emphasis on targeting of protein network in cancer cells. We partition this review into different sections, highlighting latest information from cell culture studies, preclinical and clinically oriented studies. We summarized how bioactive ingredients of Viscum album modulated extrinsic and intrinsic pathways in cancer cells. However, surprisingly, none of the study reported stimulatory effects on TRAIL receptors. The review provided in-depth analysis of how Viscum album modulated Endoplasmic Reticulum Stress in cancer cells and how bioactive chemicals tactfully targeted cytoskeletal machinery in cancer cells as evidenced by cell culture studies. It is noteworthy that Viscum album has entered into various phases of clinical trials, however, there are still knowledge gaps in our understanding regarding how various bioactive constituents of Viscum album modulate intracellular signaling cascades in cancer. Better and deeper comprehension oncogenic signaling cascades will prove to be helful in getting a step closer to individualized medicine.

Mixed protein-DNA gel particles for DNA delivery: role of protein composition and preparation method on biocompatibility.

Mixtures of two cationic proteins were used to prepare protein-DNA gel particles, employing associative phase separation and interfacial diffusion (Morán et al., 2009a). By mixing the two proteins, we have obtained particles that displayed higher loading efficiency and loading capacity values than those obtained in single-protein systems. However, nothing is known about the adverse effects on haemocompatibility and cytotoxicity of these protein-DNA gel particles. Here, we examined the interaction of protein-DNA gel particles obtained by two different preparation methods, and their components, with red blood cells and established cells. From a haemolytic point of view, these protein-DNA gel particles were demonstrated to be promising long-term blood-contacting medical devices. Safety evaluation with the established cell lines revealed that, in comparison with proteins in solution, the cytotoxicity was reduced when administered in the protein-DNA systems. In comparison with large-sized particles, the cytotoxic responses of small-sized protein-DNA gel particles showed to be strongly dependent of both the protein composition and the cell line being the tumour cell line HeLa more sensitive to the deleterious effects of the mixed protein-based particles. The observed trends in haemolysis and cell viabilities were in agreement with the degree of complexation values obtained for the protein-DNA gel particles prepared by both preparation methods.

The role of counterions in the membrane-disruptive properties of pH-sensitive lysine-based surfactants.

Surfactants are among the most versatile and widely used excipients in pharmaceuticals. This versatility, together with their pH-responsive membrane-disruptive activity and low toxicity, could also enable their potential application in drug delivery systems. Five anionic lysine-based surfactants which differ in the nature of their counterion were studied. Their capacity to disrupt the cell membrane was examined under a range of pH values, concentrations and incubation times, using a standard hemolysis assay as a model for endosomal membranes. The surfactants showed pH-sensitive hemolytic activity and improved kinetics at the endosomal pH range. Low concentrations resulted in negligible hemolysis at physiological pH and high membrane lytic activity at pH 5.4, which is in the range characteristic of late endosomes. With increasing concentration, the surfactants showed an enhanced capacity to lyse cell membranes, and also caused significant membrane disruption at physiological pH. This observation indicates that, at high concentrations, surfactant behavior is independent of pH. The mechanism of surfactant-mediated membrane destabilization was addressed, and scanning electron microscopy studies were also performed to evaluate the effects of the compounds on erythrocyte morphology as a function of pH. The in vitro cytotoxicity of the surfactants was assessed by MTT and NRU assays with the 3T3 cell line. The influence of different types of counterion on hemolytic activity and the potential applications of these surfactants in drug delivery are discussed. The possibility of using pH-sensitive surfactants for endosome disruption could hold great promise for intracellular drug delivery systems in future therapeutic applications.

First Report of Monosporascus cannonballus on Watermelon in Brazil.

In 2008 and 2009, vine decline symptoms were observed in three watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) fields located in the municipalities of Mossoró (Rio Grande do Norte State) and Quixeré (Ceará State) in northeastern Brazil. Symptoms included yellowing of crown leaves just prior to harvest and collapse of many of the vines. Mean maximum daily temperatures for the first and second half of the season were 28.6 and 25.1°C, respectively. Affected plants exhibited necrotic root systems and lacked most of the secondary and tertiary feeder roots. Numerous perithecia on the roots contained asci and ascospores characteristics of Monosporascus cannonballus Pollack & Uecker (1,2). Small pieces of primary and secondary roots were surface disinfected and plated onto potato dextrose agar (PDA) medium with 0.5 g liter-1 of streptomycin sulfate and incubated for 7 days at 25°C in the dark. Hyphal tips from all colonies were transferred to PDA and further incubated for 30 to 40 days at 25°C in the dark for subsequent growth and sporulation. Isolations consistently yielded colonies of white mycelium, which became dark grayish after 10 to 15 days, and perithecia with one-spored asci. The internal transcribed spacer regions of ribosomal DNA of isolates 18-5 and 19-1 were sequenced (GenBank Accession Nos. GQ891544 and GQ891545). These sequences were identical to sequences of M. cannonballus (GenBank Accession Nos. AM167936 and AM167937). Pathogenicity of these two isolates was confirmed on watermelon cv. Crimson Sweet in a greenhouse maintained at 25 to 30°C. Inoculum was produced in a sand-oat hulls (Avena sativa) medium (0.5 liter of sand, 46 g of ground oat hulls, and 37.5 ml of distilled water) and incubated at 25°C for 1 month. CFU were quantified by serial dilution using 1% hydroxyethyl cellulose. A sterilized mixture of equal portions (vol/vol) of sand and peat moss was used to fill 17-cm-diameter plastic pots and inoculum was added to produce an inoculum concentration of 20 CFU g-1. Five watermelon seeds planted in each pot were later thinned to one seedling per pot. There were five replicated pots for each treatment with an equal number of noninfested pots. Plants were evaluated for disease 45 days after sowing. All isolates of M. cannonballus were highly aggressive and caused severe root necrosis compared with the noninoculated controls. M. cannonballus was reisolated from symptomatic plants, confirming Koch's postulates. In 2004, M. cannonballus was reported in the same Brazilian cucurbit-growing areas causing root rot and vine decline of muskmelon (Cucumis melo L.) (3), but to our knowledge, this is the first report of M. cannonballus on watermelon in Brazil. References: (1) R. D. Martyn and M. E. Miller. Plant Dis. 80:716, 1996. (2) F. G. Pollack and F. A. Uecker. Mycologia 66:346, 1974. (3) R. Sales Jr. et al. Plant Dis. 88:84, 2004.