Carmela Saturnino

Biopolymeric self-assembled nanoparticles for enhanced antibacterial activity of Ag-based compounds

Microbial infections still remain one of the main issues for human health. The rapid development of resistance towards the most common antimicrobial drugs in bacteria represents today a challenge in the infections management. In the present work we have investigated the antibacterial activity of a group of compounds, namely silver N-heterocyclic carbene complexes, against a broad spectrum of bacteria. For the most promising compound, a biopolymeric nanocarrier has been developed, in order to potentiate the metal complex activity against both Gram +ve and Gram -ve. The polymeric nanovehicle is based on dextran, modified with oleic acid residues, that confer amphiphilic properties to the polysaccharide. We have characterized the obtained biomaterial and studied its ability to self-assemble into nanoparticles in aqueous environment. Next, the transdermal diffusion analyses have been carried out to evaluate the ability of the polymeric particles to penetrate tissues. Thanks to the strategy adopted, we have fabricated an antibacterial system to which K. pneumoniae and E. coli are the most sensitive.

Novel Gold and Silver Carbene Complexes Exert Antitumor Effects Triggering the Reactive Oxygen Species Dependent Intrinsic Apoptotic Pathway

Cisplatin and other platinum‐based drugs are well‐known valid anticancer drugs. However, during chemotherapy, the presence of numerous side effects and the onset of frequent phenomena of resistance has pushed many research groups to devise new metal‐based compounds holding improved anticancer properties and fewer undesired effects. Amongst the variety of synthesized compounds, significant antiproliferative effects have been obtained by employing organometallic compounds, particularly those based on silver and gold. With this in mind, we synthesized four compounds, two silver complexes and two gold complexes, with good inhibitory effects on the in vitro proliferation of breast and ovarian cancer‐cell models. The antitumor activity of the most active compound, that is, AuL4, was found to be ninefold higher than that of cisplatin, and this compound induced dramatic morphological changes in HeLa cells. AuL4 induced PARP‐1 cleavage, caspases 3/7 and 9 activation, mitochondria disruption, cytochrome c release in cancer‐cell cytoplasm, and the intracellular production of reactive oxygen species. Thus, AuL4 treatment caused cancer‐cell death by the intrinsic apoptotic pathway, whereas no cytotoxic effects were recorded upon treating non‐tumor cell lines. The reported outcomes may be an important contribution to the expanding knowledge of medicinal bio‐organometallic chemistry and enlarge the available anticancer toolbox, offering improved features, such as higher activity and/or selectivity, and opening the way to new discoveries and applications.

Organo-Metallic Compounds: Novel Molecules in Cancer Therapy

The discovery of cis-platin in the treatment of cancer there has been a considerable exploration on the antitumoral activity of other transition metal complexes. One of the main problems about the application of transition metal complexes for chemotherapy is their potential toxicity. Recently the attention has been focused on titanium based complexes, which could have significant potential effect against solid tumor. The advantage of Ti (IV) complexes is their relative biological compatibility, which mostly leads to mild and revisable side effects. However, the hydrolytic instability of known Ti(IV) complexes and formation of different species upon water addition makes their therapeutic application problematic, and raises a strong interest in the development of relatively stable Ti(IV) complexes with well defined hydrolytic behavior that demonstrate appreciable cytotoxic activity. Strong ligand binding is also of interest to avoid complete ligand stripping by transferrin, so that the ligand may be used as a target for structure–activity relationship investigations. Titanocene dichloride (Cp2TiCl2) shows an average antiproliferative activity in vitro and promising result in vivo. Recent work has been performed in developing therapeutic analogues of Cp2TiCl2 by varying the central metal, the labile ligands (Cl) and the biscyclopentadienyl moiety. In particular, small changes to the Cp ligand can strongly affect the hydrolytic stability and water solubility properties of the metallocenes and have an impact on the cytotoxic activity. In this review we want summarize the importance of different organo-mettalic compounds in cancer therapy with focus on possible structure modification.

N-thioalkylcarbazoles derivatives as new anti-proliferative agents: synthesis, characterisation and molecular mechanism evaluation.

Abstract Synthetic or natural carbazole derivatives constitute an interesting class of heterocycles, which showed several pharmaceutical properties and occupied a promising place as antitumour tools in preclinical studies. They target several cellular key-points, e.g. DNA and Topoisomerases I and II. The most studied representative, i.e. Ellipticine, was introduced in the treatment of metastatic breast cancer. However, because of the onset of dramatic side effects, its use was almost dismissed. Many efforts were made in order to design and synthesise new carbazole derivatives with good activity and reduced side effects. The major goal of the present study was to synthesise a series of new N-thioalkylcarbazole derivatives with anti-proliferative effects. Two compounds, 5a and 5c, possess an interesting anti-proliferative activity against breast and uterine cancer cell lines without affecting non-tumoural cell lines viability. The most active compound (5c) induces cancer cells death triggering the intrinsic apoptotic pathway by inhibition of Topoisomerase II. Graphical Abstract

Meldonium improves Huntington’s disease mitochondrial dysfunction by restoring peroxisome proliferator-activated receptor γ coactivator 1α expression: DI CRISTO et al.

Mitochondrial dysfunction seems to play a fundamental role in the pathogenesis of neurodegeneration in Huntington’s disease (HD). We assessed possible neuroprotective actions of meldonium, a small molecule affecting mitochondrial fuel metabolism, in in vitro and in vivo HD models. We found that meldonium was able to prevent cytotoxicity induced by serum deprivation, to reduce the accumulation of mutated huntingtin (mHtt) aggregates, and to upregulate the expression of peroxisome proliferator‐activated receptor γ coactivator 1α (PGC‐1α) in mHTT‐expressing cells. The PGC‐1α increase was accompanied by the increment of mitochondrial mass and by the rebalancing of mitochondrial dynamics with a promotion of the mitochondrial fusion. Meldonium‐induced PGC‐1α significantly alleviated motor dysfunction and prolonged the survival of a transgenic HD Drosophila model in which mHtt expression in the nervous system led to progressive motor performance deficits. Our study strongly suggests that PGC‐1α, as a master coregulator of mitochondrial biogenesis, energy homeostasis, and antioxidant defense, is a potential therapeutic target in HD.

Synthesis of sericin-based conjugates by click chemistry: enhancement of sunitinib bioavailability and cell membrane permeation

Abstract Sericin is a natural protein that has been used in biomedical and pharmaceutical fields as raw material for polypeptide-based drug delivery systems (DDSs). In this paper, it has been employed as pharmaceutical biopolymer for the production of sunitinib–polypeptide conjugate. The synthesis has been carried out by simple click reaction in water, using the redox couple l-ascorbic acid/hydrogen peroxide as a free radical grafting initiator. The bioconjugate molecular weight (50 kDa < Mw < 75 kDa) was obtained by SDS-PAGE, while the spectroscopic characteristics have been studied in order to reveal the presence of grafted sunitinib. In both FT-IR and UV/Vis spectra, signals corresponding to sunitinib functional groups have been identified. Since sunitinib is an anticancer drug characterized by low bioavailability and low permeability, the bioconjugation aimed at their enhancement. In vitro studies demonstrated that bioavailability has been increased to almost 74%, compared with commercial formulation. Also cell membrane permeability has been augmented in in vitro tests, in which membrane models have been used to determine the lipid membrane/physiological fluid partition coefficient (Kp). The log(Kp) value of the bioconjugate was increased to over 4. This effect resulted in a three-fold decrease of IC50 value against MCF-7 cells.