New molecular and cellular targets for chemoprevention and treatment of skin tumors by plant polyphenols: a critical review.

As the incidence of skin tumors has been steadily growing, there is an urgent need for the preventive measures as well as the improved therapeutic approaches. In the last two decades, natural plant derived polyphenols (PPs, resveratrol, silibinin, green tea polyphenols, flavonoids, anthocyanins, etc.) have been drawing particular interest as emerging active substances in dermatological/cosmeceutical compositions for the prevention, slowing, or reversion of skin tumorigenesis (chemoprevention). When chronically applied to the skin, they supposedly would not damage normal skin cells or negatively affect their functions while they would suppress tumorigenic cell transformation, inhibit tumor cell proliferation, and activate tumor cell apoptosis. PPs are also reported to synergize with conventional anti-cancer therapies. The major aim of this critical review is to provide recent updates on the molecular and cellular targets for the prevention and therapy of skin tumors with a special focus on the crossroad between inflammation and carcinogenesis as the most promising approach to chemoprevention. Novel therapeutic targets as different as epidermal stem cells, cellular senescence, epigenetic enzymes involved in carcinogenesis, epidermal growth factor and aryl hydrocarbon receptors, and metabolic CYP1 subfamily enzymes are highlighted. The mechanisms of PPs interaction with these molecular and cellular targets are reviewed. The feasibility of PPs to prevent/ cure specific cutaneous toxicity connected to anti-EGFR therapy and to reduce multidrug resistance of skin tumors is also discussed.

Activity of antioxidant enzymes in the wound in patients with deep burns.

Analysis of wound discharge in children with deep burns over 3 weeks after the injury revealed gradual increase in catalase activity. The increase in activities of myeloperoxidase, glutathione-S-transferase, and catalase was maximum in patients with the most severe burns. Local complications were observed during the period of maximum myeloperoxidase activity, while the beginning of epithelialization was associated with its reduction. Analysis of wound impressions confirms long-term persistence of neutrophils in the wound.

alpha-Fetoprotein as a modulator of the pro-inflammatory response of human keratinocytes.

BACKGROUND AND PURPOSE: The immunomodulatory effects of alpha-fetoprotein (AFP) on lymphocytes and macrophages have been described in vitro and in vivo. Recombinant forms of human AFP have been proposed as potential therapeutic entities for the treatment of autoimmune diseases. We examined the effects of embryonic and recombinant human AFP on the spontaneous, UVA- and cytokine-induced pro-inflammatory responses of human keratinocytes. EXPERIMENTAL APPROACH: Cultures of primary and immortalized human keratinocytes (HaCaT) and human blood T lymphocytes were used. The effects of AFP on cytokine expression were studied by bioplexed elisa and quantitative reverse transcriptase polymerase chain reaction assay. Kinase and nuclear factor kappa B (NFkappaB) phosphorylation were quantified by intracellular elisa. Nuclear activator protein 1 and NFkappaB DNA binding activity was measured by specific assays. Nitric oxide and H(2)O(2) production and redox status were assessed by fluorescent probe and biochemical methods. KEY RESULTS: All forms of AFP enhanced baseline expression of cytokines, chemokines and growth factors. AFP dose-dependently increased tumour necrosis factor alpha-stimulated granulocyte macrophage colony stimulating factor and interleukin 8 expression and decreased tumour necrosis factor alpha-induced monocyte chemotactic protein 1 and IP-10 (interferon gamma-produced protein of 10 kDa) expression. AFP induced a marked activator protein 1 activation in human keratinocytes. AFP also increased H(2)O(2) and modulated nitrite/nitrate levels in non-stimulated keratinocytes whereas it did not affect these parameters or cytokine release from UVA-stimulated cells. Phosphorylation of extracellular signal-regulated kinase (ERK1/2) and Akt1 but not NFkappaB was activated by AFP alone or by its combination with UVA. CONCLUSIONS AND IMPLICATIONS: Exogenous AFP induces activation of human keratinocytes, with de novo expression of a number of pro-inflammatory mediators and modulation of their pro-inflammatory response to cytokines or UVA. AFP may modulate inflammatory events in human skin.

Plant polyphenols and tumors: from mechanisms to therapies, prevention, and protection against toxicity of anti-cancer treatments.

Polyphenolic molecules produced by higher plants in response to biotic and abiotic stresses exert numerous effects on tumorigenic cell transformation, and on tumor cells in vitro and in vivo, and may interact with conventional anti-tumor therapies. In the present review, we collected and critically discussed data on: (i) redox-dependent and redox-independent mechanisms underlying cytotoxic/cytostatic effects of PPs and their metabolites towards tumor cells and cytoprotection of normal cells; (ii) mechanisms of anti-angiogenic and anti-metastatic action of PPs; (iii) PPs-associated phototoxicity against tumor cells and photoprotection of non-tumor cells; (iv) PPs effects on drug-metabolizing enzymes as a basis for their synergism or antagonism with chemotherapy; (v) molecular pathways leading to tumor chemoprevention by PPs; and (vi) PPs as protectors against toxic effects of chemo-, radio-, and photodynamic therapies.

Comparative study of cytokine content in the plasma and wound exudate from children with severe burns.

The content of 27 cytokines was measured in blood plasma from 19 children with severe uncomplicated burns (group 1) and complicated burns (septic toxemia, toxemia, and pneumonia; group 2). Before surgical treatment (day 4 (+/-2) after burn), significant differences were found in the concentrations of interleukin-1 receptor antagonist, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor-alpha, interferon-gamma, MCP-1, and granulocyte colony-stimulating factor. Cytokine concentration in group 2 patients was much higher than in group 1 patients and healthy children. The concentrations of interleukin-6, interleukin-8, and MCP-1 in group 1 patients significantly surpassed the normal level. Cytokine concentration in the plasma and wound exudates and myeloperoxidase activity in wound exudates from 4 patients of group 2 were measured over 18 days after burn. The inflammatory response was characterized by an increase in the content of interleukin-1beta, interleukin-8, MCP-1, tumor necrosis factor-alpha, MIP-1alpha, and granulocyte-macrophage colony-stimulating factor in the wound (as compared to that in the plasma). Activity of myeloperoxidase in all patients was shown to correlate with the amount of MIP-1alpha (r=0.47), tumor necrosis factor-alpha (r=0.47), and granulocyte-macrophage colony-stimulating factor (r=0.55, p<0.05). Interleukin-8 concentration was beyond the limits of calibration. No correlation was found between the concentration of any of 27 cytokines in blood plasma and exudate. Our results indicate that during active surgical treatment, the wound serves as the source of inflammatory cytokines. Cytokines play a role in the systemic response and increase the degree of local inflammation, which modulates the number and activity of wound neutrophils.

Molecular mechanisms underlying wound healing and anti-inflammatory properties of naturally occurring biotechnologically produced phenylpropanoid glycosides.

Two phenylpropanoid glycosides, verbascoside (VB) and teupolioside (TP), produced biotechnologically by Syringa vulgaris and Ajuga reptans plant cell cultures, were studied in vitro and in vivo for their anti-inflammatory and wound healing activities. It was shown that TP- and VB-containing extracts significantly accelerated wound healing and possessed remarkable anti-inflammatory action in the excision wound model. These effects correlated with the inhibition of reactive oxygen species release from the whole blood leukocytes and with the ferrous ion chelating capacity. On the other hand, they don't correlate either with free radical scavenging or with the inhibition of lipid peroxidation in the cell-free systems. Furthermore, both VB- and TP-containing extracts were extremely effective inhibitors of chemokine and growth factor expression by cultured human keratinocytes treated with pro-inflammatory cytokines, TNF-alpha and interferon-gamma.

Phenylpropanoids as naturally occurring antioxidants: from plant defense to human health.

Phenylpropanoids (PPs) belong to the largest group of secondary metabolites produced by plants, mainly, in response to biotic or abiotic stresses such as infections, wounding, UV irradiation, exposure to ozone, pollutants, and other hostile environmental conditions. It is thought that the molecular basis for the protective action of phenylpropanoids in plants is their antioxidant and free radical scavenging properties. These numerous phenolic compounds are major biologically active components of human diet, spices, aromas, wines, beer, essential oils, propolis, and traditional medicine. Last few years, much interest has been attracted to natural and synthetic phenylpropanoids for medicinal use as antioxidant, UV screens, anticancer, anti-virus, anti-inflammatory, wound healing, and antibacterial agents. They are of great interest for cosmetic and perfume industries as active natural ingredients. In the present review, the metabolic pathways of phenylpropanoid biosynthesis in plants and the mechanism of phenylpropanoid-mediated plant defense are described. Learning from plants, free radical-driven, molecular and cellular processes modulated by phenylpropanoids in human cell cultures in vitro and in the in vivo animal models of tumors, inflammation, and cellular damage are also reviewed.

Activity of antioxidant enzymes in the skin during surgical wounds.

Full-thickness skin wounds (460 mm(2)) in rats were associated with increased blood chemiluminescence and neutrophil infiltration of the wound tissue and surrounding skin (recorded by myeloperoxidase activity). Activities of glutathione peroxidase and glutathione S-transferase in the skin and wound tissue increased on days 4 and 8. A correlation was revealed between activities of these enzymes and myeloperoxidase activity. Activities of myeloperoxidase and catalase increased in patient's skin excised during plastic surgeries of more than 2.5 h duration.

Protective effect of complex antioxidant preparation containing vitamins and amino acids in rats with burn trauma complicated by endotoxemia.

Burn trauma increased blood chemiluminescence, while lipopolysaccharide in a dose of 1 mg/kg potentiated this effect, activated LPO, and decreased plasma antioxidant activity. In erythrocytes, superoxide dismutase activity increased, while activity of peroxide-utilizing enzymes decreased. Myeloperoxidase content increased in the lungs and epidermis. The preparation of alpha-tocopherol, selenium aspartate, and ubiquinone abolished the effect of lipopolysaccharide, but did not modulate the increase in chemiluminescence under the influence of this agent.

Effect of endotoxemia on skin antioxidant enzymes under experimental conditions.

Intraperitoneal injection of bacterial lipopolysaccharide in a dose of 1 mg/kg was followed by prestimulation of whole blood leukocytes in rats. Activities of peroxide- and lipoperoxide-utilizing antioxidant enzymes glutathione peroxidase, glutathione S-transferase, and catalase increased 1 day after lipopolysaccharide administration, while the content of malonic dialdehyde in the skin remained unchanged.

[Antioxidant enzymes in skin experimental burn trauma].

The effect of experimental burn trauma (20%) on myeloperoxidase (MPO) and antioxidant enzymes (catalase, glutathione peroxidase (GPO), glutathione-S-transferase (GST)) was studied in unburned skin, epidermis (20 mm from the burned area) and the wound tissue of rats. The most common features were the increase of MPO on the 1st day and a delayed increase of GPO and GST after the 4th day. The additional operations (necrectomy) and lipopolysaccharide administration induced marked inflammatory reaction in skin and epidermis (evaluated by the increase in MPO and GPO/GST activities).

[Examination of the local antioxidative system of the eye in experimental corneal burn injury and the prospects for pharmacological correction of its parameters].

The present paper deals with the study of the efficiency of oral use of the antioxidative drug Immugen (a complex of alpha-tocopherol, oubichinone, selenium aspartate, methionine, and soyabean phospholipids) on a rabbit model of severe alkaline-induced corneal burn. The investigations have indicated that addition of Immugen to the rabbit feed exerts a significant positive effect on the parameters of the local antioxidative system of the eye and causes an increase in the activity of superoxide dismutase and catalase, and, on day 14, in antioxidative activity. The early experimental periods were marked by a slight rise in the frequency of deep corneal ulcerations. Moreover, the long-term clinical effect of use of Immugen appears as a significant increase in the area of the transparency-preserving affected cornea. The findings suggest that the antioxidants can show their optimal effect in the complex therapy for burn processes, including the use of proteinase inhibitors.

Wound-healing effect of papaya-based preparation in experimental thermal trauma.

Treatment with the phytopreparation from papaya accelerated wound healing and reduced the severity of local inflammation in rats with burn wounds. The effect of this phytopreparation can be related to an increase in the effectiveness of intracellular bacterial killing by tissue phagocytes due to the inhibition of bacterial catalase. Antioxidant activity of the preparation decreases the risk of oxidative damage to tissues.

Preventive and therapeutic effect of complex antioxidant preparation in rats with burn trauma.

The production of blood radicals and activity of superoxide dismutase in erythrocytes increased in rats with contact burn trauma (20%). In animals with burn trauma antioxidant activity of the plasma was much lower, while myeloperoxidase content in the lung tissue and epidermis was higher than in control rats. The complex of antioxidants (Immudzhen) inhibited radical generation at the peak of inflammation (day 4), increased antioxidant activity of the plasma, and normalized myeloperoxidase content in the lung tissue.

Direct enzymatic reduction of lucigenin decreases lucigenin-amplified chemiluminescence produced by superoxide ion.

The interaction of superoxide ion with lucigenin produces chemiluminescence (CL), which is widely used for the detection of this radical anion. However, in many biological systems lucigenin may be directly reduced to its semiquinone by some enzymes. We found that if the direct reduction of lucigenin takes place, it decreases superoxide production due to the competition with one-electron reduction of dioxygen to superoxide ion. Comparison of two methods of superoxide detection (lucigenin-amplified CL and cytochrome c reduction) showed that there are excellent correlations between the results obtained by the two methods. Hence, lucigenin-amplified CL remains a sensitive and reliable assay of superoxide detection.

Influence of metal ions on flavonoid protection against asbestos-induced cell injury.

Influence of metal ions (Fe2+, Fe3+, Cu2+, Zn2+) on the protective effect of rutin, dihydroquercetin, and green tea epicatechins against in vitro asbestos-induced cell injury was studied. Metals have been found to increase the capacity of rutin and dihydroquercetin to protect peritoneal macrophages against chrysotile asbestos-induced injury. The data presented here show that this effect is due to the formation of flavonoid metal complexes, which turned out to be more effective radical scavengers than uncomplexed flavonoids. At the same time epicatechins and their metal complexes have similar antiradical properties and protective capacities against the asbestos induced injury of macrophages. Metal complexes of all flavonoids were found to be considerably more potent than parent flavonoids in protecting red blood cells against asbestos-induced injury. It was also found that the metal complexes of all flavonoids were absorbed by chrysotile asbestos fibers considerably better than uncomplexed compounds and probably for this reason flavonoid metal complexes have better protective properties against asbestos induced hemolysis. Thus, the results of the present study show that flavonoid metal complexes may be effective therapy for the inflammatory response associated with the inhalation of asbestos fiber. The advantage of their application could be the strong increase in ROS scavenging by flavonoids and finally a better cell protection under the conditions of cellular oxidative stress.

The role of oxidative stress in developmental and reproductive toxicity of tamoxifen.

The antiestrogen tamoxifen (TAM) is widely used as a drug against breast cancer and is currently being tested as a chemopreventive agent. However, a number of studies showed genotoxic and carcinogenic effects of TAM. These effects are thought to be related to oxygen radical overproduction which occurs during TAM metabolic activation. There is no evidence, thus far, on TAM toxicity to embryos and gametes. The present study was designed to elucidate the mechanisms of TAM-induced developmental, reproductive and cytogenetic toxicity towards sea urchin (SU) embryos with regard to the possibility of TAM-initiated oxidative stress. Embryo cultures from SU were subjected to long-term (throughout embryogenesis) or short-term (two hours) incubation with TAM at concentrations from 10(-8) to 10(-5) M. The experiments on TAM-induced toxicity to gametes were carried out with SU sperm, or unfertilized eggs, suspended in TAM (10(-8) to 10(-6) M). To assess the effects of TAM to embryos or to gametes, developmental defects, embryonic mortality, fertilization success, and cytogenetic abnormalities were scored. Oxidative damage to DNA and lipids was detected by measurements of 8OHdG levels and lipid peroxidation, respectively. Reactive oxygen species (ROS) production by eggs and embryos was recorded by luminol-dependent chemiluminescence (LDCL) and cytochrome c reduction methods. The changes in activities of SU superoxide dismutase (SOD) and catalase were also evaluated. TAM exerted: a) early embryonic mortality to exposed embryos and to the offspring of exposed eggs; b) developmental defects to the offspring of exposed sperm; c) decrease in sperm fertilization success, and d) cytogenetic effects in the offspring of exposed sperm or eggs. These morphological effects corresponded to the state of oxidative stress in SU embryos (increased oxidative damage to DNA and lipids and induction of antioxidant enzymes). Since TAM did increase significantly ROS production by embryos, it is suggested that TAM may be metabolically activated by SU embryonic oxidases and peroxidases, which in turn could be induced by TAM. The present study provides further support to the utilization of the SU system as a useful model to help elucidate mechanisms of chemical teratogenesis and carcinogenesis.

Enhancement of antioxidant and anti-inflammatory activities of bioflavonoid rutin by complexation with transition metals.

The antioxidant and anti-inflammatory activities of two transition metal complexes of bioflavonoid rutin, Fe(rut)Cl(3) and Cu(rut)Cl(2), were studied. It was found that Cu(rut)Cl(2) was a highly efficient in vitro and ex vivo free radical scavenger that sharply decreased (by 2-30 times compared to the parent rutin): oxygen radical production by xanthine oxidase, rat liver microsomes, and rat peritoneal macrophages; the formation of thiobarbituric acid-reactive products in microsomal lipid peroxidation; and the generation of oxygen radicals by broncho-alveolar cells from bleomycin-treated rats. The copper-rutin complex was also a superior inhibitor of inflammatory and fibrotic processes (characterized by such parameters as macrophage/neutrophil ratio, wet lung weight, total protein content, and hydroxyproline concentration) in the bleomycin-treated rats. The antioxidant activity of Fe(rut)Cl(3) was much lower and in some cases approached that of rutin. Fe(rut)Cl(3) also stimulated to some degree spontaneous oxygen radical production by macrophages. We suggested that the superior antioxidant and anti-inflammatory activity of the copper-rutin complex is a consequence of its acquiring the additional superoxide-dismuting copper center. The inhibitory activity of Fe(rut)Cl(3) was lower, probably due to the partial reduction into Fe(rut)Cl(2) in the presence of biological reductants; however, similarly to the copper-rutin complex, this complex efficiently suppressed lung edema.

Spectrin changes occur in erythrocytes from patients with Fanconi's anemia and their parents.

Fanconi's anemia (FA) is a clinically and genetically heterogeneous disease which has been hypothesized to be defective in the detoxification of reactive oxygen species. In this work we report the results obtained by morphometric analyses on the red blood cells (RBCs) from FA patients and their parents. We found that a high rate of erythrocytes from both homozygous and heterozygous subjects was significantly altered. RBCs underwent in fact cytoskeleton-dependent modifications, in particular of spectrin molecule, leading to cell shrinking and blebbing. We hypothesize that these changes may be the result of an oxidative imbalance that probably lead to alterations of RBC plasticity- and deformation-associated functions. Moreover, our results also suggest the possibility to identify FA carriers by the existence of RBC abnormalities.