Search

Aberrant transglutaminase 2 (TG2) expression and protein cross-linking activity have been associated with several chronic neurodegenerative disorders in which inflammatory processes triggered by activated microglia and monocytes play a key role, such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis. Interestingly, mild-to-moderate hyperhomocysteinemia (HHcy), corresponding to increased plasma homocysteine (Hcy) concentrations in the range 16-60 μM, have recently been associated with the above-cited diseases. Using THP-1 monocytes, here we investigated the role of TG2 in cell response to mildly elevated Hcy concentrations. A five-day incubation with Hcy (∼25 μM) increased reactive oxygen species, peroxide lipids, as well as 8-hydroxyguanosine levels by twofold, and decreased the endogenous cell antioxidant defenses, that is reduced glutathione, by 50% in Hcy-exposed cultures compared with controls ( p < 0.01). Hcy-induced oxidative stress was associated with increases in TG2 expression and activity, as well as nuclear factor kappa B activation. Notably, the latter was reduced in the presence of the TG-specific inhibitor R283. Hcy exposure also significantly increased the mRNA levels of tumor necrosis factor alpha, interleukin (IL)-6, and IL-1β, as well as the level of Hcy-inducible endoplasmic reticulum (ER) stress protein, a marker of ER stress, in Hcy-exposed cultures compared with controls. Notably, these effects were dramatically reduced by R283. These preliminary findings indicate that TG2 plays a key role in Hcy-induced activation of THP-1 monocytes, involving oxidative as well as ER stress and inflammation. This underlines the potential of TG2 inhibition in the therapeutic management of inflammatory processes contributing to neurodegenerative disorders associated with mild HHcy. [ABSTRACT FROM AUTHOR]

Single nucleotide polymorphism (SNP) in the human Tumor Necrosis Factor-a(TNF-α) gene promoter, the -308 G/A variant, has been associated with increased TNF-α levels that may amplify the severity of rheumatoid arthritis (RA) and a poor responsiveness to TNF-α blockade therapy. High mobility group box protein (HMGB-1) is a pro-inflammatory cytokine that plays a pivotal role in the pathogenesis of RA and may be an original target of therapy. The aim of this study is to investigate whether the -308 G/A variant of the TNF-α gene is associated with altered expression of HMBG-1. A total of 110 consecutive patients with rheumatoid arthritis and spondylo-arthritis (ankylosing spondylitis, psoriatic arthritis and spondylitis associated with inflammatory bowel disease) referring to the Rheumatology Unit of Messina University Hospital were enrolled. Patients were genotyped for the -308 TNF-α gene promoter polymorphism. Clinical status was also assessed. HMGB-1 and TNF-α mRNA (Real Time PCR) from total blood and plasmatic HMGB-1 (Western Blot analysis) and TNF-α (ELISA) protein were also evaluated. Irrespective of the underlying disease, patients carrying the G/A genotype showed enhanced HMGB-1 and TNF-α mRNA levels and increased circulating concentration of the inflammatory cytokines when compared to patients with G/G genotype. The data suggest that subjects carrying the TNF-α -308G/A genotype have enhanced expression of HMGB-1 protein that may explain, at least in part, the increased severity of the disease. [ABSTRACT FROM AUTHOR]

Background Bergamot essential oil (BEO) is obtained from the fruit peel of Citrus bergamia (bergamot), a small tree cultivated almost exclusively along the southern coast of the Calabria region of Italy. BEO is appreciated for its organoleptic properties and is widely used in the manufacture of perfumes. The goals of our study were to investigate the mechanisms underlying the antiproliferative effects of BEO and to identify the compounds mainly responsible for its inhibition of SH-SY5Y cell growth. Methods Five BEO extractive fractions (BEOs) differing in chemical composition were used. Cell proliferation was determined by MTT and cell count assays. The trypan blue exclusion test and annexin V/PI staining were done to assess their cytotoxic activity. Genotoxic effects were detected by the comet assay. The cell cycle was also analysed cytofluorimetrically. Reactive oxygen species and Δ ψ m were measured fluorimetrically. Western blotting analyses for some apoptosis-related proteins were carried out. Findings Treatment of SH-SY5Y cells with some types of BEOs decreased rate of cell growth by a mechanism correlated to both apoptotic and necrotic cell death. Coloured BEOs act by increasing generation of reactive oxygen species, responsible for the drop in Δ ψ m, and modulating p38 and ERK1/2 MAPKs, p53, Bcl-2 and Bax signalling pathways. Finally, we identified bergamottin and 5-geranyloxy-7-methoxycoumarin as the bioactive molecules that play a pivotal part in the antiproliferative effects exerted by coloured BEOs. Interpretation Our study provides novel insights into the antiproliferative effects of BEO, which could be exploited in the context of multitarget pharmacological strategies. [ABSTRACT FROM AUTHOR]

Background Increasing interest in the antitumour activity of several fruit juices and vegetable extracts led us to investigate the antitumour effects of bergamot juice in in vitro models. Citrus bergamia Risso et Poiteau (bergamot) is a small tree cultivated almost exclusively along the southern coast of the Calabria region of Italy. Bergamot fruit is used mostly for the extraction of its essential oil widely used in perfume industry, whereas bergamot juice is considered secondary product. Methods We assessed the ability of bergamot juice to reduce the growth rate of different cancer cell lines, observing the maximal antiproliferative effect in neuroblastoma cells. We also focused on the flavonoid fraction of bergamot juice (FFBJ). Findings The SH-SY5Y growth inhibition elicited by bergamot juice was not due to a cytotoxic action or apoptosis. Instead, bergamot juice stimulated the arrest of the cell cycle in the G1 phase and determined a modification in cellular morphology, causing a marked increase in detached cells. The inhibition of the adhesive capacity on different physiological substrates and on the endothelial cell monolayer were correlated with impairment of actin filaments and reduction in the expression of the active form of focal adhesion kinase (FAK) that in turn caused inhibition of cell migration. Interpretation Our results suggest that the FFBJ inhibits HT-29 human colorectal carcinoma cell growth and induces apoptosis by multiple mechanisms. Molecular assays revealed that higher concentration of FFBJ increases production of reactive oxygen species, which causes loss in mitochondrial membrane potential and oxidative DNA damage. Lower concentrations of FFBJ inhibit MAPK pathways and alter apoptosis-related proteins, and in turn induce cell cycle arrest and apoptosis. In conclusion, we have shown that bergamot juice exerts important anti-cancer effects in vitro by different mechanisms involved in the regulation of cell growth, adhesiveness, migration, and invasion, depending on its concentration and cell lines. [ABSTRACT FROM AUTHOR]

Abstract Background Perinatal exposure to hyperhomocysteinemia might disturb neurogenesis during brain development and growth. Also, high levels of homocysteine trigger neurodegeneration in several experimental models. However, the putative mechanisms of homocysteine-induced toxicity in the developing nervous system have poorly been elucidated. This study was aimed to investigate homocysteine effects in undifferentiated neuroblastoma cells, Neuro2a. Results A 4 h exposure to homocysteine in a concentration range of 10–100 μM did not affect cell viability and ROS production in Neuro2a cell cultures. Instead, ROS levels were increased by two-three folds in cells treated with 250 μM and 500 μM homocysteine, respectively, in comparison with control cells. Also, the highest homocysteine dose significantly reduced the viable cell number by 40%. Notably, the treatment with homocysteine (250 μM–500 μM) in the presence of antioxidants, such as N-acetylcysteine and IRFI 016, a synthetic α-tocopherol analogue, recovered cell viability and significantly reduced homocysteine-evoked increases in ROS production. Moreover, antioxidants, particularly IRFI 016, were able to counteract NF-κB activation induced by 250 μM homocysteine. Cell treatment with 250 μM homocysteine also triggered the onset of apoptosis, as demonstrated by the increased expression of early apoptotic markers such as Bax, caspase-3 and p53. In contrast, Bcl2 expression was not affected by homocysteine exposure. Interestingly, the specific inhibition of NF-κB nuclear translocation by the synthetic peptide SN50 was able to almost completely suppress the homocysteine-evoked rises in pro-apoptotic protein expression as well as in caspase-3 activity. Further, also IRFI 016 and N-acetylcysteine were able to significantly reduce caspase-3 activation induced by homocysteine treatment. Conclusion These observations suggest an involvement of redox state alterations and activated NF-κB in apoptosis onset triggered by homocysteine in neuroblastoma cells Neuro2a. However, further investigations are needed to characterize molecular events involved in the NF-κB activation induced by homocysteine.

Abstract: Neuroblastoma is the most common extracranial pediatric solid tumor with poor prognosis in children with disseminated stage of disease. A number of studies show that molecules largely distributed in commonly consumed fruits and vegetables may have anti-tumor activity. In this study we evaluate the effect of Citrus bergamia (bergamot) juice (BJ) in vitro and in a spontaneous metastatic neuroblastoma SCID mouse model. Qualitative and quantitative characterizations of BJ flavonoid fractions were performed by RP-HPLC/PDA/MS. We show that BJ significantly affects SK-N-SH and LAN-1 cell proliferation in vitro, but fails to reduce primary tumor weight in vivo. Moreover, BJ reduced cell adhesiveness and invasion of LAN-1 and SK-N-SH cells in vitro and the number of pulmonary metastases under consideration of the number of tumor cells in the blood in mice inoculated with LAN-1 cells in vivo. These effects without any apparent sign of systemic toxicity confirm the potential clinical interest of BJ and lay the basis for further investigation in cancer. [Copyright &y& Elsevier]

Background Natural extracts from various citrus species have shown promising antitumour effects. In this study we evaluated the effects of the flavonoid fraction of Citrus reticulata (mandarin) juice (FFMJ) on both proliferation and migration of three human anaplastic thyroid carcinoma (ATC) cell lines. Methods FFMJ was analysed by uHPLC to elucidate its components. Findings Treatment of CAL-62, C-643, and 8505C cells with rising concentrations of FFMJ significantly reduced cell proliferation in a concentration-dependent and time-dependent manner, with maximal effect elicited at 0.5 mg/ml concentration after 48 h of incubation. Moreover, cytofluorimetric analysis showed a block of the cell cycle in the G2/M phase, accompanied by low cell mortality resulting from autophagic death. Furthermore, FFMJ inhibited migration of ATC cells and was associated with decreased activity of the metalloproteinase MMP-2. Interpretation These finding demonstrate that FFMJ exerts antiproliferative effects on ATC cells together with reducing their migration properties, suggesting a promising role in the prevention or treatment of thyroid cancer. [ABSTRACT FROM AUTHOR]