Laura Lombardo

Lichen metabolites prevent UV light and nitric oxide-mediated plasmid DNA damage and induce apoptosis in human melanoma cells.

In humans both UV-A and UV-B can cause gene mutations and suppress immunity, which leads to skin cancer, including melanoma. Inhibition of reactive oxygen species (ROS) and reactive nitrogen species (RNS) appears particularly promising as ROS and RNS production by both UV-A and UV-B contributes to inflammation, immunosuppression, gene mutation and carcinogenesis. We evaluated the effect of two lichen compounds, sphaerophorin (depside) and pannarin (depsidone) on pBR322 DNA cleavage induced by hydroxyl radicals (()OH), and by nitric oxide (NO), and their superoxide anion (O(2)(-)) scavenging capacity. In addition, we investigated the growth inhibitory activity of these compounds against human melanoma cells (M14 cell line). Sphaerophorin and pannarin showed a protective effect on plasmid DNA and exhibited a superoxide dismutase like effect. The data obtained in cell culture show that these lichen metabolites inhibit the growth of melanoma cells, inducing an apoptotic cell death, demonstrated by the fragmentation of genomic DNA (COMET and TUNEL Assays) and by a significant increase of caspase-3 activity, and correlated, at least in part, to the increase of ROS generation, These results confirm the promising biological properties of sphaerophorin and pannarin and encourage further investigations on their molecular mechanisms.

Induction of Nuclear Receptors and Drug Resistance in the Brain Microvascular Endothelial Cells Treated with Antiepileptic Drugs

Our work contributes to the understanding of the mechanisms of drug resistance in epilepsis. This study aimed to investigate i) the levels of expression of P-glycoprotein (P-gp), and multidrug resistance-associated proteins (MRP)1 and 2, ii) the activation of the pregnane X receptor (PXR) and the constitutive androstane receptor (CAR), and iii) the relationship between increased P-gp and MRPs expression and PXR and CAR activation, in immortalized rat brain microvascular endothelial cell lines, GPNT and RBE4, following treatment with the antiepileptic drugs (AEDs), topiramate, phenobarbital, carbamazepine, tiagabine, levetiracetam, and phenytoin, using Western blotting and immunocytochemistry methods. Carbamazepine, phenobarbital and phenytoin induced the highest levels of P-gp and MPRs expression that was associated with increased activation of PXR and CAR receptors as compared to levetiracetam, tiagabine and topiramate. We conclude that P-gp and MRPs are differently overexpressed in GPNT and RBE4 by various AEDs and both PXR and CAR are involved in the drug-resistant epilepsy induced by carbamazepine, phenobarbital and phenytoin.

Antiproliferative Activity of Methylated Analogues of E- and Z-Resveratrol

Abstract The stilbenoids E-resveratrol (E-3,5,4′-trihydroxystilbene, 1), E-3,5,4′-trimethoxystilbene (2), E-3,4,4′-trimethoxystilbene (3) and E-3,4′-dimethoxy-5-hydroxystilbene (4) were converted by photoisomerization to their corresponding Z-isomers 5D8. Compounds 1D8 were subjected to antiproliferative activity bioassays towards a set of four different human cancer cell lines, namely DU-145 (androgen not responsive human prostate tumor), LNCaP (androgen responsive human prostate tumor), M-14 (human melanoma) and KB (human mouth epidermoid carcinoma). The methylated analogues of 1 are more active than the natural lead in the majority of bioassays. The most active compound was Z-3,5,4′-trimethoxystilbene (6), which showed against DU-145 and LNCaP cells GI50 values close to those of the anticancer drug vinorelbine; 6 resulted more active than its E-isomer 2 towards DU-145, LNCaP and especially KB cell lines. A number of methylated Z-isomers displayed a higher activity than their E-isomers, but E-resveratrol (1) was more active than Z-resveratrol (5) towards all the tested cell lines.

Eugenol and its synthetic analogues inhibit cell growth of human cancer cells (Part I)

Eugenol (4-allyl-2-methoxyphenol) (1) has been reported to possess antioxidant and anticancer properties. In an attempt to enhance intrinsic activity of this natural compound, some derivatives were synthesized. Eugenol was extracted from cloves oil and further, the eugenol analogues (2-6) were obtained through acetylation and nitration reactions. Eugenol (1) and its analogues (2-6) were examined by in vitro model of cancer using two human cancer cell lines: DU-145 (androgen-insensitive prostate cancer cells) and KB (oral squamous carcinoma cells). Cell viability, by tetrazolium salts assay, was measured. Lactic dehydrogenase (LDH) release was also investigated to evaluate the presence of cell toxicity as a result of cell disruption, subsequent to membrane rupture. In the examined cancer cells, all compounds showed cell-growth inhibition activity. The obtained results demonstrate that the compounds 5-allyl-3-nitrobenzene-1,2-diol (3) and 4-allyl-2-methoxy-5-nitrophenyl acetate (5) were significantly (p < 0,001) more active than eugenol, with IC50 values in DU-145 cells of 19.02 x 10-6 and 21.5 × 10-6 mol L-1, respectively, and in KB cells of 18.11 × 10-6 and 21.26 × 10-6 mol L-1, respectively, suggesting that the presence of nitro and hydroxyl groups could be important in the activity of these compounds. In addition, our results seem to indicate that apoptotic cell demise appears to be induced in KB and DU-145 cells. In fact, in our experimental conditions, no statistically significant increase in LDH release was observed in cancer cells treated with eugenol and its analogues.

In vitro study of biofunctional indicators after exposure to asbestos-like fluoro-edenite fibres.

The in vitro biological response to fluoro-edenite (FE) fibres, an asbestos-like amphibole, was evaluated in lung alveolar epithelial A549, mesothelial MeT-5A and monocyte-macrophage J774 cell lines. The mineral has been found in the vicinity of the town of Biancavilla (Catania, Sicily), where an abnormal incidence of mesothelioma has been documented. Cell motility, distribution of polymerized actin, and synthesis of vascular endothelial growth factor (VEGF) and of beta-catenin, critical parameters for tumour development, progression and survival, were investigated in A549 and MeT-5A cells exposed to 50 microg/ml FE fibres for 24 hr and 48 hr. The levels of cyclooxygenase (COX-2) and prostaglandin (PGE2), two molecules involved in cancer pathogenesis by affecting mitogenesis, cell adhesion, immune surveillance and apoptosis, were measured in J774 cells treated with FE fibres under the same experimental conditions. Finally, FE fibres were studied by SEM and EDS analysis to investigate their chemical composition. Exposure of A549 and MeT-5A cells to FE fibres affected differentially phalloidin-stained cytoplasmic F-actin networks, cell motility and VEGF and beta-catenin expression according to the different sensitivity of the two cell lines. In J774 cells it induced a significant increase in COX-2 expression, as assessed by Western blot analysis, and in the concentration of PGE2, measured in culture media by ELISA. SEM-EDS investigations demonstrated two types of FE fibres, edenite and fluoro-edenite, differing in chemical composition and both recognizable as calcic amphiboles. Fibre width ranged from less than 1 microm (prevalently 0.5 microm) to 2-3 microm (edenite) up to several microm (fluoro-edenite); length ranged from about 6 to 80 microm (edenite) up to some hundred microm (fluoro-edenite). Results provide convincing evidence that FE fibres are capable of inducing in vitro functional modifications in a number of parameters with crucial roles in cancer development and progression. Inhaled FE fibres have the potential to induce mesothelioma, even though their ability to penetrate lung alveoli depends on their aerodynamic diameter.

Inhibition of iNOS and COX-2 in human whole blood ex vivo and monocyte-macrophage J774 cells by a new group of aminothiopyrimidone derivatives

We tested a series of 11 new aminothiopyrimidones on the activity of inducible nitric oxide synthase (iNOS) and prostaglandin G/H synthase-1 and 2 (COX-1 and COX-2) in the whole human blood and monocyte-macrophage J774 cell line. To induce COX-2 and iNOS, blood samples and J774 cells were stimulated with bacterial lipopolysaccharide (LPS) in the absence or presence of the test compounds. After incubation, the plasma and the supernatants of culture media were collected for the measurement of TxB(2) and PGE(2) by a specific enzyme-immunoassay and determination of nitrite by a colorimetric assay. Several phenylthieno derivatives of substituted pyrimidone inhibited formation of both COX-2 and iNOS derived products with one of the compounds (compound 11, N-[2-[(2,4-dinitrophenyl)thio]-4-oxo-6-phenylthieno[2,3-d]pyrimidin-3(4H)-y]methanesulfonamide) showing a complete inhibition of LPS-stimulated formation of NO and PGE(2).

Fluoro-edenite fibers induce expression of Hsp70 and inflammatory response

Many asbestos-like mineral fibers have been detected in the air of mountainous and volcanic areas of Italy and other parts of the world. These fibers have been suspected to be the cause of increased incidences of lung cancer and other lung diseases in these areas. However, the mechanisms of the cellular response and defense following exposure to these microscopic fibers have not been characterized. We continue to study these mechanisms to be able to propose preventive strategies in large populations. The objective of the present study was to determine comparatively biological responses of mesothelial Met-5A and monocyte-macrophage J774 cells following exposure to two types of fluoro-edenite fibers having low and high iron content (labeled 19 and 27, respectively) obtained from Biancavilla (Sicily, Italy). The reference fiber was a non-iron fibrous tremolite from Val di Susa (Piemonte, Italy). The cells were treated with 5, 50, and 100 μg of fibrous matter per 1 ml for 72 hr. We identified several key mechanisms by which cells responded and counteracted the injury induced by these fibers. The fibers caused induction of the heat shock protein 70 (Hsp70), stimulated formation of reactive oxygen species (detected by using DCFH-DA as a fluorescent probe) and NO • (measured as nitrite). Exposure of cells to the fibers induced lactate dehydrogenase activity and decreased viability. The fluoro-endenite type 27 was the most potent fiber tested, which indicated that iron and possibly manganese contribute significantly to this fiber toxicity. The J774 cells were more sensitive to fluoro-edenite than Met-5A cells suggesting that the primary site of the fiber- induced inflammatory response could be the macrophage rather than the pulmonary epithelium. Fluoro-edenite produces more biological alterations with respect to non-iron tremolite. Hsp70 and free radicals could be important factors in the context of mineral fiber-induced acute lung injury leading possibly to mutagenic effects. We anticipate that pharmacological blockade of the fiber-dependent cellular responses could in long term offer preventive approach to combat lung diseases induced by these fibers.