Formulation matters! A spectroscopic and molecular dynamics investigation on the peptide CIGB552 as itself and in its therapeutical formulation

Synthetic therapeutic peptides (STP) are intensively studied as new-generation drugs, characterized by high purity, biocompatibility, selectivity and stereochemical control. However, most of the studies are focussed on the bioactivity of STP without considering how the formulation actually used for therapy administration could alter the physico-chemical properties of the active principle. The aggregation properties of a 20-mer STP (Ac-His-Ala-Arg-Ile-Lys-D-Pro-Thr-Phe-Arg-Arg-D-Leu-Lys-Trp-Lys-Tyr-Lys-Gly-Lys-Phe-Trp-NH₂), showing antitumor activity, were investigated by optical spectroscopy and atomic force microscopy imaging, as itself (CIGB552) and in its therapeutic formulation (CIGB552TF). It has found that the therapeutic formulation deeply affects the aggregation properties of the investigated peptide and the morphology of the aggregates formed on mica by deposition of CIGB552 and CIGB552TF millimolar solutions. Molecular dynamics simulations studied the first steps of CIGB552 aggregation under physiological ionic strength conditions (NaCl 150 mM), showing that peptide oligomers, from dimers to tetramers, are preferentially formed in this environment. Interestingly, cell viability assays performed on H-460 cell lines indicate a major antiproliferative activity of the peptide in its therapeutic formulation with respect to the peptide aqueous solution.     

Accurate and efficient gp120 V3 loop structure based models for the determination of HIV-1 co-receptor usage

Background  

HIV-1 targets human cells expressing both the CD4 receptor, which binds the viral envelope glycoprotein gp120, as well as either the CCR5 (R5) or CXCR4 (X4) co-receptors, which interact primarily with the third hypervariable loop (V3 loop) of gp120. Determination of HIV-1 affinity for either the R5 or X4 co-receptor on host cells facilitates the inclusion of co-receptor antagonists as a part of patient treatment strategies. A dataset of 1193 distinct gp120 V3 loop peptide sequences (989 R5-utilizing, 204 X4-capable) is utilized to train predictive classifiers based on implementations of random forest, support vector machine, boosted decision tree, and neural network machine learning algorithms. An in silico mutagenesis procedure employing multibody statistical potentials, computational geometry, and threading of variant V3 sequences onto an experimental structure, is used to generate a feature vector representation for each variant whose components measure environmental perturbations at corresponding structural positions.     

A mammary adenocarcinoma murine model suitable for the study of cancer immunoediting

Background

Cancer immunoediting is a dynamic process composed of three phases: elimination (EL), equilibrium (EQ) and escape (ES) that encompasses the potential host-protective and tumor-sculpting functions of the immune system throughout tumor development. Animal models are useful tools for studying diseases such as cancer. The present study was designed to characterize the interaction between mammary adenocarcinoma M-406 and CBi, CBi⁻ and CBi/L inbred mice lines.

Results

The mammary adenocarcinoma M-406 developed spontaneously in a CBi mouse. CBi/L and CBi⁻ mice were artificially selected for body conformation from CBi. When CBi mice are s.c. challenged with M-406, tumor growths exponentially in 100% of animals, while in CBi⁻ the tumor growths briefly and then begins a rejection process in 100% of the animals. In CBi/L the growth of the tumor shows the three phases: 51.6% in ES, 18.5% in EQ and 29.8% in EL.

Conclusions

The results obtained support the conclusion that the system M-406 plus the inbred mouse lines CBi, CBi⁻ and CBi/L, is a good murine model to study the process of tumor immunoediting.     

The aggressiveness of murine lymphomas selected in vivo by growth rate correlates with galectin-1 expression and response to cyclophosphamide

Although lymphomas account for almost half of blood-derived cancers that are diagnosed each year, the causes of new cases are poorly understood, as reflected by the relatively few risk factors established. Galectin-1, an immunoregulatory ?-galactoside-binding protein, has been widely associated with tumor-immune escape. The aim of the present work was to study the relationship between tumor growth rate, aggressiveness, and response to cyclophosphamide (Cy) therapy with regard to Gal-1 expression in murine T-cell lymphoma models. By means of a disruptive selection process for tumor growth rate, we generated two lymphoma variants from a parental T-cell lymphoma, which have unique characteristics in terms of tumor growth rate, spontaneous regression, metastatic capacity, Gal-1 expression and sensitivity to Cy therapy. Here, we show that Gal-1 expression strongly correlates with tumor growth rate, metastatic capacity and response to single-dose Cy therapy in T-cell lymphoma models; this association might have important consequences for evaluating prognosis and treatments of this type of tumors.     

Performance of cowpea as influenced by native strain of rhizobia,lime and phosphorus in Samaru,Nigeria

Arsenic (As) is a toxic metalloid that has gained special interest in the past years as a global environmental problem. Groundwater in Córdoba province (Argentina) presents high As concentrations which can be absorbed by plants or be used for artificial irrigation. The aim of this research was to elucidate the differential responses of symbiotic interactions established with three bacterial strains and soybean plants to realistic doses of arsenic. The reference strain Bradyrhizobium diazoefficiens USDA110 and the native isolate Bradyrhizobium sp. Per 3.64 were able to grow up to 13 mM As(V) whereas the native strain Bradyrhizobium sp. Per 3.61 grew up to 9.5 mM As(V). Metalloid addition did not modify the soybean plant growth at 6 μM As(V). Nevertheless, it was enough to induce oxidative stress as observed by an increase on lipid peroxidation. The soybean-Bradyrhizobium sp. assay at 6 μM As(V) showed no changes in growth variables (shoot and root dry weight) in plants inoculated with the reference microsymbiont or Bradyrhizobium sp. Per 3.61. Regarding As uptake by plants, metalloid accumulation followed the same distribution pattern among strains. Remarkably, at 6 μM As(V), soybean inoculation with Bradyrhizobium sp. Per 3.61 revealed a significantly lower translocation factor (TF) in comparison to other inoculated strains promoting As phytostabilization. At the highest As(V) concentration tested, only Bradyrhizobium diazoefficiens USDA110 was able to nodulate the legume, however, a significant decrease in the number and dry weight of nodules and nitrogen content was observed. In conclusion, the inoculation of soybean plants with the reference strain Bradyrhizobium diazoefficiens USDA110 exposed to high As(V) concentration represents an effective and promising symbiotic interaction that allows the development of the legume due to the minimal effects on plant growth. However, in low As(V) concentration environments, the native isolate Bradyrhizobium sp. Per 3.61, is shown to be the best inoculant among the tested strains, owing to the limitation of metalloid translocation and accumulation to edible parts of the legume, avoiding fruit contamination and human poisoning.     

Correction to: Performance of cowpea as influenced by native strain of rhizobia,lime and phosphorus in Samaru,Nigeria

Garden thyme (Thymus vulgaris L., Lamiaceae) is an important aromatic herb used for its medicinal values including antioxidant and antimicrobial properties. The present study was performed to analyze the changes in natural antioxidants after inoculation of in vitro propagated garden thyme plants with arbuscular mycorrhizal fungi (AMF). An efficient and low-cost protocol for large-scale multiplication of this aromatic plant was developed. The explants were cultured on full and half strength Murashige and Skoog (MS) medium containing indole-3-butyric acid (IBA). The maximum number of shoots and roots was obtained on ½ MS medium supplemented with 0.1 mg L^?1 IBA after 4 weeks of culture. The successfully adapted in vitro plants (survival rate 95%) were inoculated with arbuscular mycorrhizal fungi (Claroideoglomus claroideum, ref. EEZ 54). Plants were then transferred into field conditions. Mycorrhizal fungi enhanced the activity of some soil enzymes, acid and alkaline phosphatase, urease as well as the levels of extractable glomalin-related proteins in plant rhizosphere. Arbuscular mycorrhizal associations with higher plants promote the accumulation of antioxidant metabolites such as phenols and flavonoids and increase the activity of antioxidant enzymes. The results from the present study suggest enhanced antioxidant capacity of the inoculated T. vulgaris plants which was due mainly to increased accumulation of phenolic compounds (total phenols and flavonoids) together with stimulation of the activity of superoxide dismutase (SOD) and guaiacol peroxidase (GPO).     

Novel albendazole formulations given during the intestinal phase of Trichinella spiralis infection reduce effectively parasitic muscle burden in mice

Trichinellosis is a zoonotic disease affecting people all over the world, for which there is no speedy and reliable treatment. Albendazole (ABZ), an inexpensive benzimidazole used in oral chemotherapy against helminthic diseases, has a broad spectrum activity and is well tolerated. However, the low absorption and variable bioavailability of the drug due to its low aqueous solubility are serious disadvantages for a successful therapy. In this study, we evaluated the in vivo antiparasitic activity of three novel solid microencapsulated formulations, designed to improve ABZ dissolution rate, in a murine model of trichinellosis. Both ABZ and the microparticulate formulations were administered during the intestinal phase of the parasite cycle, on days 5 and 6 post-infection. This protocol significantly decreased muscle larval burden measured in the parenteral phase, on day 30 post-infection, when compared with the untreated control. Moreover, two of the three microencapsulated formulations both strongly and consistently reduced worm burden.