Differential anti-cancer effects of purified EPA and DHA and possible mechanisms involved.

As the concepts of pharmaconutrition are receiving increasing attention, it seems essential to clearly assess the effects of specific dietary compounds in specific groups of patients or clinical conditions. We are herein interested in better defining the differential anti-neoplastic effects of the two major n-3 long chain polyunsaturated fatty acids present in fish oil, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The efficiency of these fatty acids represents a subject of intense interest and debate, and whereas plenty of preclinical studies have strongly demonstrated their preventive and therapeutic effect in different kinds of cancers, the results of the epidemiologic studies are still controversial, and only a few trials have been performed. It has been reported that EPA and DHA may act either through the same or different mechanisms, thus suggesting that a differential efficacy could exist. At present, however, this point has not been clarified, although its better comprehension would allow a more proper and effective use of these fatty acids in the human interventional studies. In an attempt to elucidate this aspect we have herein analyzed the data obtained in the studies which have directly compared the antitumor effects of separate treatments with EPA or DHA. Most of the in vitro data indicate DHA as the more powerful antineoplastic agent. However, an equivalent efficiency of EPA and DHA is suggested by the few in vivo studies. Possible reasons for this discrepancy are discussed and pathways of cell growth that could be differentially influenced by EPA and DHA are described.

Sclerodermus domesticus infestation.

AIM: Sclerodermus domesticus is an insect belonging to the order Hymenoptera. Female of S. domesticus feeds on larvae of xylophagous Coleoptera and Lepidoptera living in the galleries they dig in old wooden furniture. Human infestation is rare. METHODS: In the last few months, we observed nine adult patients (7 males and 2 females) who were affected by S. domesticus infestation. Seven patients were antiquarians or restorers and two were housewives. The rash was characterized by erythematous-papular lesions, accompanied by pruritus and/or pain. In addition, 7 patients reported general malaise and fever. In all cases it was possible to find specimens of S. domesticus in furniture or house dust. RESULTS: Complete remission was obtained with topical corticosteroids, oral anti-histamines and pest control of furniture. CONCLUSION: Antiquarians and restorers and, in general, the people in close contact with furniture infested by S. domesticus may be stung by these insects. S. domesticus infestation can therefore be considered as an occupational disease in these subjects.

Chemoprevention of lung pathologies by dietary n-3 polyunsaturated fatty acids.

Different intervention trials have been so far conducted and others are ongoing to evaluate the effect of increased intake of n-3 polyunsaturated fatty acids (PUFAs) in the prevention of several disorders affecting lungs and airways. They have been focused on chronic obstructive pulmonary disease, acute respiratory distress syndrome, acute lung injury, pulmonary fibrosis, alteration of lung function in cystic fibrosis, as well as asthma and cachexia in lung cancer patients. Their outcomes are not always consistent, but, if beneficial effects were observed, they have been related mainly to the anti-inflammatory action of n-3 PUFAs. On the contrary, trials investigating their effects on the development and progression of lung cancer are still not available. This in spite of the huge number of equivalent studies performed on other kind of cancers (breast, colon and prostate cancer), which share with lung cancer the highest incidence in Western countries and an elevated sensitivity to chemoprevention. Contrasting results were also obtained by the few epidemiological studies available on lung cancer. However, different experimental studies, performed in vivo and in vitro, provided strong indications of the anti-tumor action of n-3 PUFAs against lung cancer, and identified molecular mechanisms for their action. In this review our effort will concentrate in critically reviewing the current evidence for the beneficial effect of n-3 PUFAs in inflammatory and neoplastic disorders of lungs and airways, and in identifying possible molecular mechanisms underlying their effects.

Dietary n-3 PUFA vascular targeting and the prevention of tumor growth and age-related macular degeneration.

The protective role of dietary n-3 polyunsaturated fatty acids (PUFAs) against cardiovascular diseases has been partly related to their ability to modulate the risk condition known as "endothelial dysfunction", by reverting the endothelial alterations associated to it (reduced vascular reactivity, the proinflammatory state, and the prothrombotic properties). Moreover, vasculature represents the target for inhibition of pathologic neo-angiogenesis by n-3 PUFAs. This effect is believed to contribute to the beneficial action of these fatty acids against disorders which recognize neovascularization as a crucial pathogenetic step for their development, such as cancer and age-related macular degeneration (AMD). Many epidemiological studies have been conducted to evaluate the association between the intake of these fatty acids and the risk of developing cancer or AMD, even though contrasting and not definitive results have been obtained. Conversely, plenty of preclinical and in vitro experimental studies have provided evidence for the anti-angiogenic effects of n-3 PUFAs, mainly studying neo-angiogenesis in general (using normal endothelial cells in vitro) or as a step of cancer growth. The main aim of this review is to critically review the current evidence for the inhibition of the neo-angiogenic process exerted by n-3 PUFAs in cancer and AMD, and to identify possible molecular mechanisms that might contribute to their beneficial effects.

Antineoplastic effects of n-3 polyunsaturated fatty acids in combination with drugs and radiotherapy: preventive and therapeutic strategies.

Many data support the beneficial effect of n-3 polyunsaturated fatty acids (PUFAs) as chemopreventive and chemotherapeutic agents in the treatment of several chronic pathologies including cancer. Different molecular mechanisms have been proposed to explain their effects, including alterations in arachidonic acid oxidative metabolism and metabolic conversion of n-3 PUFAs to novel discovered bioactive derivatives; modification of oxidative stress; changes in cell membrane fluidity and structure and altered metabolism and function of membrane proteins. Considerable knowledge has been recently gathered on the possible beneficial effects of n-3 PUFAs administered in combination with different antineoplastic drugs and radiotherapy against melanoma, leukemia, neuroblastoma, and colon, breast, prostate, and lung cancer. The efficacy of these combinations has been demonstrated both in vivo and in vitro, and clinical trials have also been conducted. The aim of this review is to analyze all the n-3 PUFA combinations investigated so far, their efficacy, and the possible molecular mechanisms involved. It would be highly auspicable that the detailed analysis of the literature in this field could further support the common use of n-3 PUFAs in combination with other chemopreventive agents and warrant more clinical investigations designed to test the effectiveness of n-3 PUFA treatments coupled with conventional antineoplastic therapies.

N-3 polyunsaturated fatty acid effect in periodontal disease: state of art and possible mechanisms involved.

Anti-inflammatory properties have been widely reported for n-3 polyunsaturated fatty acids (PUFAs) and some studies have been focalized on their possible role in the modulation of gingivitis and alveolar bone resorption in periodontal disease (PD). Increased formation of arachidonic acid-derived inflammatory eicosanoids and augmented oxidative stress are two molecular mechanisms pathogenetically involved in the progression of PD and known to be inhibited by n-3 PUFAs in PD setting. The present review will focus also on other molecular pathways and factors known to be altered in the development of PD and known to be subject to n-3 PUFA modulation in other pathological settings different from PD. Overall, the available findings strongly encourage further experimental studies on animals subject to experimental PD and treated with n-3 PUFAs, long term n-3 PUFA intervention studies on PD patients and molecular studies to identify additional potential molecular routes of n-3 PUFA action in PD.

n-3 polyunsaturated fatty acids and the prevention of colorectal cancer: molecular mechanisms involved.

Increasing evidence supports the hypothesis that nutrition habits play a critical role in the incidence and growth of colorectal cancer. Among dietary factors, fish-derived n-3 polyunsaturated fatty acids (PUFAs) have gained particular interest, since epidemiological studies have shown a reduced incidence of this cancer in populations consuming high levels of fish. Also a variety of experimental studies and different clinical trials substantiated the beneficial role of n-3 PUFAs. Such an anti-neoplastic activity has been related to the regulatory effects exhibited by n-3 PUFAs on cell proliferation and apoptosis. Anti-angiogenic and anti-metastatic effects have been also reported for these fatty acids. Finally, it has been suggested that they may act as adjuvant therapeutic agents sensitizing tumors, including colon cancer, to different anti-neoplastic drugs. Several molecular mechanisms have been hypothesized to explain their anti-neoplastic action and, in particular, the modulating effect on the expression of several proteins involved in the regulation of cell cycle and apoptosis, such as Bcl-2, Bax, c-Myc seem to play a central role. Their inhibitory action has been also recently suggested for the molecular pathways driven by COX-2 and beta-catenin, known to play a major role in the development and progression of colon cancer. The aim of the present review is to analyze the anti-neoplastic effect of n-3 PUFAs towards colon cancer, and examine the molecular mechanisms involved.

Dual role of beta-carotene in combination with cigarette smoke aqueous extract on the formation of mutagenic lipid peroxidation products in lung membranes: dependence on pO2.

Results from some intervention trials indicated that supplemental beta-carotene enhanced lung cancer incidence and mortality in chronic smokers. The aim of this study was to verify the hypothesis that high concentrations of the carotenoid, under the pO2 present in lung (100-150 mmHg), may exert deleterious effects through a prooxidant mechanism. To test this hypothesis, we examined the interactions of beta-carotene and cigarette smoke condensate (tar) on the formation of lipid peroxidation products in rat lung microsomal membranes enriched in vitro with varying beta-carotene concentrations (from 1 to 10 nmol/mg prot) and then incubated with tar (6-25 microg/ml) under different pO2. As markers of lipid peroxidation, we evaluated the levels of conjugated dienes and malondialdehyde, possessing mutagenic and pro-carcinogenic activity. The exposure of microsomal membranes to tar induced a dose-dependent enhancement of lipid peroxidation, which progressively increased as a function of pO2. Under a low pO2 (15 mmHg), beta-carotene acted clearly as an antioxidant, inhibiting tar-induced lipid peroxidation. However, the carotenoid progressively lost its antioxidant efficiency by increasing pO2 (50-100 mmHg) and acted as a prooxidant at pO2 ranging from 100 to 760 mmHg in a dose-dependent manner. Consistent with this finding, the addition of alpha-tocopherol (25 microM) prevented the prooxidant effects of the carotenoid. beta-Carotene auto-oxidation, measured as formation of 5,6-epoxy-beta,beta-carotene, was faster at high than at low pO2 and the carotenoid was more rapidly consumed in the presence of tar. These data point out that the carotenoid may enhance cigarette smoke-induced oxidative stress and exert potential deleterious effects at the pO2 normally present in lung tissue.

Differentiation between field and vaccine strain of bluetongue virus serotype 16.

In August 2000, bluetongue virus (BTV) appeared for the first time in Sardinia and, since then, the infection spread across Sicily and into the mainland of Italy involving at the beginning serotypes 2 and 9 and then, from 2002, 4 and 16. To reduce direct losses due to disease and indirect losses due to new serotype circulation, the 2004 Italian vaccination campaign included the modified-live vaccines against BTV-4 and 16 produced by Onderstepoort Biological Product (OBP), South Africa. Few months after the end of the campaign, BTV-16 was reported broadly in the country and the need of differentiating field from the BTV-16 vaccine isolate became crucial. In this study, the gene segments 2, 5, 6 and 10 of both the Italian and vaccine BTV-16 strains were sequenced and their molecular relationship determined. As sequences of segment 5 were those showing the highest differences (17.3%), it was possible to develop a new diagnostic tool able to distinguish the Italian BTV-16 NS1 gene from that of the homologous vaccine strain. The procedure based on the use of a RT-PCR and the subsequent sequencing of the amplified product showed a high degree of sensitivity and specificity when samples from either BTV-16 vaccinated or infected sheep were tested.

Lycopene induces apoptosis in immortalized fibroblasts exposed to tobacco smoke condensate through arresting cell cycle and down-regulating cyclin D1, pAKT and pBad.

There is a lot of interest in the health benefits of dietary carotenoids and on the relationship of these compounds with smoke. In particular, it is unknown if the enhanced cancer risk observed in smokers following beta-carotene supplementation can be also found using other carotenoids. Here, we studied the effects of the tomato carotenoid lycopene on molecular pathways involved in cell cycle progression, apoptosis and survival in immortalized RAT-1 fibroblasts exposed to cigarette smoke condensate (TAR). Lycopene (0.5-2.0 microM) inhibited cell growth in a dose-and time-dependent manner, by arresting cell cycle progression and by promoting apoptosis in cells exposed to TAR. The arrest of cell cycle was independent of p53 and of 8-OH-dG DNA damage and related to a decreased expression of cyclin D1. Moreover, the carotenoid up-regulated apoptosis and down-regulated the phosphorylation of AKT and Bad in cells exposed to TAR. Such an effect was associated to an inhibition of TAR-induced expression of Cox-2 and hsp90, which is known to maintain AKT activity. This study suggests that lycopene, differently from beta-carotene, can exert protective effects against cigarette smoke condensate.

Redox regulation of cell proliferation by pyrrolidine dithiocarbamate in murine thymoma cells transplanted in vivo.

Pyrrolidine dithiocarbamate (PDTC) is a synthetic compound largely used in cell biological studies and known to exert either antioxidant or pro-oxidant effects. Recently, its antitumoral activity has been proposed on the basis of its antioxidant and proapoptotic effects. In the present study, we evaluated the effect of increasing i.p. doses of PDTC on the growth of a strain of highly malignant thymoma cells inoculated in the peritoneum of inbred Balb/c mice. PDTC treatment increased the number of thymoma cells in a dose-dependent manner, enhancing the percentage of proliferating tumor cells. PDTC exerted regulatory effects on cell cycle distribution, decreasing the expression of cell cycle inhibitors. Alterations in the production of intracellular reactive oxygen species, levels of oxidized glutathione, and intracellular levels of the redox-active metals iron and copper were also observed. The above results represent the first evidence that PDTC may induce in vivo cell proliferation in a murine thymoma cell model. In addition, we suggest that the ability of PDTC to bind and transport metals inside the cell and its pro-oxidant property may be factors underlying its effects on thymoma cell proliferation and cell cycle distribution.

beta-carotene at high concentrations induces apoptosis by enhancing oxy-radical production in human adenocarcinoma cells.

This is the first report demonstrating a relationship between apoptosis induction and changes of intracellular redox potential in the growth-inhibitory effects of high concentrations of beta-carotene in a tumor cell line. beta-Carotene inhibited the growth of human WiDr colon adenocarcinoma cells in a dose- and time-dependent manner, induced apoptosis, and blocked Bcl-2 expression. These effects were accompanied by an enhanced production of intracellular reactive oxygen species (ROS). The addition of the antioxidant alpha-tocopherol blocked both the pro-oxidant and the growth-inhibitory effects of the carotenoid. These findings suggest that beta-carotene may act as an inductor of apoptosis by its pro-oxidant properties.

Mitogenic and apoptotic signaling by carotenoids: involvement of a redox mechanism.

The potential for carotenoids to modulate tumor growth is currently under investigation. Although epidemiological studies evidence that a high intake of vegetables, rich in carotenoids, decreases cancer incidence and mortality, clinical trials demonstrate that supplementation of beta-carotene to chronic smokers or to asbestos workers increases the risk for lung cancer. These contradictory findings have renewed interest in elucidating the mechanism of action of carotenoids in biological systems. In this review, we show evidence for mitogenic and apoptotic effects of carotenoids and we support the hypothesis that these molecules may act as anticarcinogens or as procarcinogens through a redox mechanism. In particular, we report demonstrations for the anti-oxidant or pro-oxidant effects of carotenoids in vitro and in vivo, focusing our attention on the relationship existing between cell growth and redox status.

Canthaxanthin supplementation alters antioxidant enzymes and iron concentration in liver of Balb/c mice.

The 4,4'-diketo-beta-carotene, canthaxanthin, alters tocopherol status when fed to Balb/c mice, suggesting an involvement of carotenoids in the modulation of oxidative stress in vivo. We investigated further the modifications induced by an oral administration of canthaxanthin on lipid peroxidation, antioxidant enzymes and iron status in liver of Balb/c mice. Female 6-wk-old Balb/c mice were randomly divided into two groups (n = 10/group). The control group (C) received olive oil alone (vehicle) and the canthaxanthin-treated group (Cx) received canthaxanthin at a dose of 14 microg/(g body wt.d). The 15-d canthaxanthin treatment resulted in carotenoid incorporation but did not modify lipid peroxidation as measured by endogenous production of malondialdehyde (MDA). However, glutathione peroxidase activity was 35% lower (P<0.01) and catalase (59%, P<0.005) and manganese superoxide dismutase (MnSOD) (28%, P<0.05) activities were higher in canthaxanthin-treated mice than in controls. Moreover, carotenoid feeding caused a significant (P<0.05) overexpression of the MnSOD gene; mRNA levels of the enzyme were greater in treated mice than in controls. Concomitantly, a 27% (P<0.05) greater iron concentration was found in liver from canthaxanthin-treated mice compared with controls. These findings support the hypothesis that canthaxanthin alters the protective ability of tissues against oxidative stress in vivo.

Supplementation with canthaxanthin affects plasma and tissue distribution of alpha- and gamma-tocopherols in mice.

The effects of oral doses of canthaxanthin on tissue distribution of alpha- and gamma-tocopherols were investigated in three experiments in male and female Balb/c mice. Mice were assigned to receive canthaxanthin [7 or 14 microg/(g body weight.d)] or placebo (olive oil) by gavage for different periods of time (0, 1, 2, 4 and 6 wk). A 2 wk-treatment with canthaxanthin resulted in incorporation of the carotenoid in all tissues analyzed, including liver, spleen, kidney, lung and heart. In liver, the maximum accumulation of the carotenoid was reached after 2 wk of dosing in female mice and after 6 wk in male mice. Canthaxanthin incorporation was accompanied by changes in alpha- and gamma-tocopherol concentrations in plasma and tissues. These included the following: 1) a significant increase (P < 0.001) in alpha-tocopherol concentration in spleen (21 and 27% in male and female mice, respectively) after 2 wk and in liver ( approximately 50% in both male and female mice) after 6 wk; 2) a significant decrease in gamma-tocopherol concentration in plasma (P < 0.05) and tissues (P < 0.001) after 2 wk of treatment. In female mice, this decrease was 55% in plasma, 43% in liver, 44% in kidney, 71% in lung and 70% in heart. In male mice, the decrease was observed only in plasma (30%), kidney (54%) and heart (46%). In liver, the decrease in gamma-tocopherol concentration was both dose- and time-dependent and significantly (P < 0.001) greater in female than in male mice. We conclude that dietary administration of canthaxanthin modifies tocopherol status in murine tissues.

Antitumor effect of an oral administration of canthaxanthin on BALB/c mice bearing thymoma cells.

The antitumor effect of canthaxanthin in BALB/c mice bearing a transplantable thymoma was investigated. Male or female mice received two different doses of canthaxanthin (7 or 14 micrograms/g body wt/day) starting 15 days before tumor inoculation (7 x 10(7) cells i.p.). Canthaxanthin treatment delayed the appearance of macroscopic ascites and prolonged animal survival. This effect was dose dependent and more evident in females than in males. It appeared only when the carotenoid was administered before tumor transplantation. The antitumor efficacy of the carotenoid was related to its tissue incorporation. Canthaxanthin was incorporated in a dose-dependent manner in liver and thymoma cells and to a larger extent in females than in males. Our study shows the antitumor efficacy of canthaxanthin in vivo against a transplantable murine thymoma and points out the importance of dose, administration timing, and sex in the antitumor efficacy of this compound.