In Vitro and Preclinical Antitumor Evaluation of Doxorubicin Liposomes Coated with a Cholesterol-Based Trimeric ß-D-Glucopyranosyltriazole.

The coating of liposomes with polyethyleneglycol (PEG) has been extensively discussed over the years as a strategy for enhancing the in vivo and in vitro stability of nanostructures, including doxorubicin-loaded liposomes. However, studies have shown some important disadvantages of the PEG molecule as a long-circulation agent, including the immunogenic role of PEG, which limits its clinical use in repeated doses. In this context, hydrophilic molecules as carbohydrates have been proposed as an alternative to coating liposomes. Thus, this work studied the cytotoxicity and preclinical antitumor activity of liposomes coated with a glycosyl triazole glucose (GlcL-DOX) derivative as a potential strategy against breast cancer. The glucose-coating of liposomes enhanced the storage stability compared to PEG-coated liposomes, with the suitable retention of DOX encapsulation. The antitumor activity, using a 4T1 breast cancer mouse model, shows that GlcL-DOX controlled the tumor growth in 58.5% versus 35.3% for PEG-coated liposomes (PegL-DOX). Additionally, in the preliminary analysis of the GlcL-DOX systemic toxicity, the glucose-coating liposomes reduced the body weight loss and hepatotoxicity compared to other DOX-treated groups. Therefore, GlcL-DOX could be a promising alternative for treating breast tumors. Further studies are required to elucidate the complete GlcL-DOX safety profile.

Mono and dinuclear platinum and palladium complexes containing adamantane-azole ligands: DNA and BSA interaction and cytotoxicity.

Synthesis of dinuclear oxadiazole-adamantane platinum(II) and palladium(II) complexes (PtO, PdO) and mononuclear thiazolidine derivative complexes (PtT, PdT) was described. Characterization was performed by elemental analysis, infrared, UV-visible, 1H, 13C, 195Pt NMR spectra, MS spectroscopy and single crystal X-ray diffraction. The cytotoxicity by MTT assay against tumor and normal cell lines with or without extracellular GSH was also investigated. In general, mononuclear complexes containing thiazolidine-adamantane ligands were more cytotoxic than oxadiazole-adamantane derivatives. PtT complex proved to be as active as cisplatin. Dinuclear compounds were considered inactive to cells in evaluated conditions, due to their high stability with ligands in a chelated and bridged way. Results suggest that GSH cannot be considered a target. DNA- and BSA-binding interactions were evaluated using UV-visible and fluorescence spectroscopy, intercalating dyes and molecular docking. Upon coordination to platinum(II), the cytotoxic effect was appreciably improved against tested cell lines, in comparison to free thiazolidine ligand. Comparing thiazolidine derivatives, it is noticeable that the less active compound (PdT) presents stronger interaction with BSA, while PtT has the weaker interaction with BSA and relatively strong binding to isolated DNA, resulting in the most cytotoxic complex. This work shows that the presence of metal is significant but it should be available for interaction. The high lability of palladium complex made this stay retainable in BSA and two metal atoms do not increase activity if it is not able to do any interaction.

Protective factors in mature human milk: a look into the proteome and peptidome of adolescent mothers' breast milk.

The characterisation of proteome and peptidome of adolescent mothers' breast milk brings important information to both mother's and infant's health; however, it has not been investigated. Bioactive peptides derived from milk proteins have numerous functions. The bioactivity of breast milk peptides includes anti-inflammatory and antimicrobial activities and regulation of gastrointestinal function. We aimed to characterise the proteome and peptidome of mature breast milk of adolescent mothers and investigate whether it is affected by lactational period. We used a combination of electrophoretic and nano-scale LC-quadrupole time-of-flight MS/MS (nLC-Q-TOF-MS/MS) techniques and bioinformatics to explore the proteome of human skimmed milk expressed by lactating adolescents in two groups according to postpartum period (up to 3 and over 5 weeks postpartum). This is the first study that analysed the proteome of adolescent mothers' breast milk produced during two periods of lactation using 1D-electrophoresis combined with nLC-Q-TOF-MS/MS analysis. Our results showed that the protein composition of adolescent milk varies independently of lactation stage and showed high inter-individual variation. A total of 424 proteins were identified in skimmed milk, of which 137 proteins were common to both groups. Most of the peptides found in adolescents' breast milk were not derived from major proteins in milk. Association maps showed several interactions between groups of peptides that pointed to the relevance of breast milk peptides to neonatal defensive system.

Polypeptides secreted from the columnar vesicles of the sea anemone Bunodosoma cangicum and their in vivo effects on Caenorhabditis elegans.

In this study we provide new evidence that the columnar vesicles of the sea anemone Bunodosoma cangicum are toxic in vivo and contain at least two active polypeptides, a neurotoxic and an apoptosis inducing polypeptide. Here we show that it is also an effective inducer of apoptosis in vivo in the nematode Caenorhabditis elegans. In addition, the anemone peptides rapidly paralyze C. elegans, and set in motion a sequence of events that result in the complete dissolution of the internal organs in adult animals within 60 min. Nematodes that survive the toxin treatment exhibit a decreased reproductive capacity. Interestingly, adult animals appear to be much more susceptible to the effects of the toxins than larval stages, suggesting possible developmentally dependent targets of the toxins. Here we also provide chemical characterization of the compounds through chromatographic analysis and mass spectrometry. Gel filtration chromatography coupled with reverse phase HPLC shows that our partially purified extract contains at least two principle components. Additionally, MALDI-TOF mass spectrometry analysis of our extract shows three principal compounds at 814.6, 2914.1, and 4360.3 m/z plus three other minor components or fragments. Mass spectrometry analysis also indicates the presence of three disulfide bridges. Which is in agreement with other characterizations of anemone venoms.

Synthesis of cholesterol-based neoglycoconjugates and their use in the preparation of liposomes for active liver targeting.

Carbohydrate receptors on liver represent attractive targets for receptor-mediated delivery of nanostructured therapeutics. In this study, two new cholesterol-based glycoconjugates derived from d-galactose and N-acetylglucosamine were synthesized and incorporated into liposomes. 99mTc-Cholesterol-DTPA complex was used for radiolabeling experiments in vivo with high radiochemical yields and stability. Biodistribution studies confirmed the targeting of galactosylated liposomes (GalL) to liver cells. These results indicated that GalL could be considered a promising drug delivery system for liver diseases therapy.

4-Nerolidylcatechol and its synthetic analogues: antioxidant activity and toxicity evaluation.

4-Nerolidylcatechol (1) is a secondary metabolite of plants and is described as a promising anti-inflammatory, antimalarial, antiulcerogenic, analgesic and cytotoxic compound possibly due to its antioxidant profile. In this study, we evaluated the pharmacologic activity and the antioxidant and toxicological profiles of compound (1) and its synthetic analogues (2-6). The synthetic analogues were designed from the lead compound, (1), using a molecular-simplification strategy. Compound 5 showed, by 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ß-carotene systems, similar antioxidant activity when compared to compound (1). The oxidative stress in erythrocyte membrane demonstrated the highly protective effect of compounds (4), (5) and (6) and high antioxidant/pro-oxidant activity in relation to the concentrations of compounds (1) and (3). Compounds (2), (4), (5) and (6) were haemobiocompatible. All compounds (1-6) showed cytotoxic effects in 3T3 cells, but compounds (2) and (6) were highly cytotoxic in this lineage when compared to compound (1). Compound (5) had a lower myelosuppressive effect in haematopoietic progenitor cells compared to (1). Both compounds, (1) and (5), showed low genotoxic effects in vitro, on human lymphocyte cells. In addition, these compounds also showed low-toxicity in vivo as defined a LD50 > 2000 mg/kg. In this assay, we did not observe death in the animals exposed to treatment with (1) and (5) compound. In conclusion, the structural design of the analogues as validated once compound (5) was found to have an antioxidant profile that was as potent as the lead compound (1). In addition, considering the safety profile, these compounds are promising as preventive and/or therapeutic agents against oxidative damage.