The causes and prevention of cancer

Method validation by interlaboratory studies of improved hydrophilic oxygen radical absorbance capacity methods for the determination of antioxidant capacities of antioxidant solutions and food extracts

Hydrophilic oxygen radical absorbance capacity (H-ORAC) is a method for evaluating antioxidant capacities of solutions of hydrophilic compounds. In this study, we improved the original method for H-ORAC determination, and evaluated the precision of the two improved methods (methods A and B) by interlaboratory studies using 5 antioxidant solutions and 5 food extracts as test samples. An interlaboratory study of method A, in accordance with the harmonized protocol, demonstrated satisfactory performance (intermediate precision relative standard deviations (RSD(int)) ranging from 4.6 to 18.8%; the reproducibility relative standard deviations (RSD(R)) ranging from 7.0 to 21.1%, and the HorRat values ranging from 0.40 to 1.93). However, methodological problems remained, and a further improved method, method B, was thus developed. An interlaboratory study of method B by 5 participating laboratories showed better intermediate precision and reproducibility (RSD(int) and RSD(R) ranging from 1.8 to 9.4%, and from 4.4 to 13.8%, respectively), and all HorRat values for the test samples were less than 1.3, suggesting good performance for the H-ORAC measurement.

Protective effects of Chlorella-derived peptide against UVC-induced cytotoxicity through inhibition of caspase-3 activity and reduction of the expression of phosphorylated FADD and cleaved PARP-1 in skin fibroblasts

UVC irradiation induces oxidative stress and leads to cell death through an apoptotic pathway. This apoptosis is caused by activation of caspase-3 and formation of poly(ADP-ribose) polymerase-1 (PARP-1). In this study, the underlying mechanisms of Chlorella derived peptide (CDP) activity against UVC-induced cytotoxicity were investigated. Human skin fibroblasts were treated with CDP, vitamin C, or vitamin E after UVC irradiation for a total energy of 15 J/cm². After the UVC exposure, cell proliferation and caspase-3 activity were measured at 12, 24, 48, and 72 h later. Expression of phosphorylated FADD and cleaved PARP-1 were measured 16 h later. DNA damage (expressed as pyrimidine (6-4) pyrimidone photoproducts DNA concentration) and fragmentation assay were performed 24 h after the UVC exposure. Results showed that UVC irradiation induced cytotoxicity in all groups except those treated with CDP. The caspase-3 activity in CDP-treated cells was inhibited from 12 h onward. Expression of phosphorylated FADD and cleaved PARP-1 were also reduced in CDP-treated cells. Moreover, UVC-induced DNA damage and fragmentation were also prevented by the CDP treatment. This study shows that treatment of CDP provides protective effects against UVC-induced cytotoxicity through the inhibition of caspase-3 activity and the reduction of phosphorylated FADD and cleaved PARP-1 expression.

Oxidative stress and programmed cell death in yeast

Yeasts, such as Saccharomyces cerevisiae, have long served as useful models for the study of oxidative stress, an event associated with cell death and severe human pathologies. This review will discuss oxidative stress in yeast, in terms of sources of reactive oxygen species (ROS), their molecular targets, and the metabolic responses elicited by cellular ROS accumulation. Responses of yeast to accumulated ROS include upregulation of antioxidants mediated by complex transcriptional changes, activation of pro-survival pathways such as mitophagy, and programmed cell death (PCD) which, apart from apoptosis, includes pathways such as autophagy and necrosis, a form of cell death long considered accidental and uncoordinated. The role of ROS in yeast aging will also be discussed.

Antioxidant and immunity activities of Fufang Kushen Injection Liquid

We investigated the effects of Fufang Kushen Injection Liquid (FFKSIL) on gastric immunity and oxidant-antioxidant status during N-methyl-N′-nitro-N-nitroso-guanidine (MNNG)-induced gastric carcinogenesis. The extent of lipid peroxidation and the levels of reduced glutathione (GSH) and activities of the GSH-dependent enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were used to monitor the peroxidative balance. Enhanced lipid peroxidation in the gastric cancer animals was accompanied by significant decreases in the activities of GSH, GPx, GST and GR. Administration of FFKSIL significantly enhanced serum IgA, IgG, IgM, IL-2, IL-4 and IL-10 levels, decreased serum IL-6 and TNF-α levels, lowered the levels of lipid peroxides and enhanced GSH levels and activities of GSH-dependent enzymes. Our results suggest that FFKSIL blocks experimental gastric carcinogenesis by protecting against carcinogen-induced oxidative damage and improving immunity activity.

Increased risk of lung cancer associated with a functionally impaired polymorphic variant of the human DNA glycosylase NEIL2

Human NEIL2, one of five oxidized base-specific DNA glycosylases, is unique in preferentially repairing oxidative damage in transcribed genes. Here we show that depletion of NEIL2 causes a 6-7-fold increase in spontaneous mutation frequency in the HPRT gene of the V79 Chinese hamster lung cell line. This prompted us to screen for NEIL2 variants in lung cancer patients' genomic DNA. We identified several polymorphic variants, among which R103Q and R257L were frequently observed in lung cancer patients. We then characterized these variants biochemically, and observed a modest decrease in DNA glycosylase activity relative to the wild type (WT) only with the R257L mutant protein. However, in reconstituted repair assays containing WT NEIL2 or its R257L and R103Q variants together with other DNA base excision repair (BER) proteins (PNKP, Polβ, Lig IIIα and XRCC1) or using NEIL2-FLAG immunocomplexes, an ~5-fold decrease in repair was observed with the R257L variant compared to WT or R103Q NEIL2, apparently due to the R257L mutant's lower affinity for other repair proteins, particularly Polβ. Notably, increased endogenous DNA damage was observed in NEIL2 variant (R257L)-expressing cells relative to WT cells. Taken together, our results suggest that the decreased DNA repair capacity of the R257L variant can induce mutations that lead to lung cancer development.

Efficacy of Different Fractions of Anethum graveolens Leaves on Serum Lipoproteins and Serum and Liver Oxidative Status in Experimentally Induced Hypercholesterolaemic Rat Models

Over the last few years, many studies have focused on plants with therapeutic properties. Anethum graveolens L. (Umbilliferae) is used as an anti-hypercholesterolaemic plant in Iranian folk medicine. This study was to disclose the antioxidant and hypolipidaemic properties of different fractions of the Anethum graveolens extract (AGE), evaluated in hypercholesterolaemic rats. The animals were divided into five groups, Group I served as healthy control; groups II to V were made hypercholesterolaemic by feeding high-fat diet (HFD) for 3 weeks. After induction of hypercholesterolaemia, the rats in groups III to V received different fractions [diethyl ether (EEF), ethyl acetate (EAF) and water (WF) fractions, respectively] of the AGE at a dose of 50 mg/kg body weight per day for 2 weeks. Feeding HFD increased serum total cholesterol (TC), triglyceride (TG) and LDL-cholesterol significantly in Group II as compared to Group I. Treatments of rats with fractions EEF, EAF and WF caused a significant decrease in TC, TG and LDL-C levels by (53.8, 49.9 and 42.3%), (51.5, 38.45 and 30.5%) and (54.8, 51.4 and 41.8%), respectively, however the HDL-cholesterol level was increased. In an effort to gain some knowledge about the mechanism of action, the effects of different fractions on oxidative stress induced by HFD were also investigated. Treatment with different fractions of AGE significantly increased hepatic antioxidant system activities such as SOD, CAT and GSH, along with decreased lipid peroxidation in HFD treated rats. Among these fractions, EEF showed the highest and WF showed the lowest increase in the above mentioned factors. Based on these results, it can be concluded that different fractions of AGE especially EEF, besides its hypolipidaemic property, could protect the liver against the HFD-induced oxidative damage in rats.

Analysis of in vitro chemoprevention of genotoxic damage by phytochemicals, as single agents or as combinations

Cancer chemoprevention with low-dose combinations of bioactive phytochemicals instead of single agents has been suggested to induce less toxicity and improve efficacy. In this study, we selected four plant food-based phytochemicals, viz. chlorogenic acid (CLA), pelargonidin (PEL), resveratrol (RES) and epigallocatechin gallate (EGCG) to evaluate the in vitro chemoprevention of genotoxic damage in HL-60 cells. These agents were tested either individually or as a combination at two concentrations (with a 10-fold difference) against the genotoxins mitomycin C (MMC), diepoxybutane (DEB) and patulin (PAT). Our preliminary ferric reducing antioxidant power (FRAP) assay demonstrated additive effects when PEL, CLA, RES and EGCG were combined. Results of the cytokinesis-block micronucleus test showed significant protection against genotoxic damage induced by PAT, DEB and MMC when CLA, PEL, RES and EGCG were tested individually. This protective effect of the phytochemicals was not concentration-related. Both low- and high-concentration combinations of CLA, PEL, RES and EGCG showed significant reducing effects on the frequencies of micronuclei induced by PAT, DEB and MMC. However, the micronucleus test did not provide indications of additive or synergistic effects with this combination of phytochemicals. In conclusion, the chemo-preventive effects of PEL, CLA, RES and EGCG against genotoxic damage induced by MMC, DEB and PAT are indicative of a 'saturation effect' when higher concentrations and combinations of these phytochemicals are used.

Ciprofloxacin photosensitized oxidation of 2'-deoxyguanosine-5'-monophosphate in neutral aqueous solution

Laser flash photolysis studies have been carried out to investigate the reactions of ciprofloxacin (CPX) with 2'-deoxyguanosine-5'-monophosphate (dGMP), N, N, N', N'-tetramethyl-p-phenylenediamine (TMPD) and ferulic acid (FCA) in neutral aqueous solutions, respectively. CPX triplet state ((3)CPX*) can be quenched by TMPD, FCA and dGMP, with rate constants of 1.8 × 10(9), 1.5 × 10(9) and 5.8 × 10(7) dm(3) mol(-1) s(-1), respectively. TMPD radical cation (TMPD(·+)) and FCA radical cation (FCA(·+)) were observed directly. The formation rate of CPX radical anion (CPX(·-)) was determined to be 1.5 × 10(9) dm(3) mol(-1) s(-1). Redox reaction of dGMP was investigated through competing reactions using TMPD and FCA as probe. The triplet energy of CPX was determined to be 262 kJ mol(-1). Electron transfer from TMPD, FCA and dGMP to (3)CPX* was proposed.

Antioxidant-induced INrf2 (Keap1) tyrosine 85 phosphorylation controls the nuclear export and degradation of the INrf2-Cul3-Rbx1 complex to allow normal Nrf2 activation and repression

INrf2 (Keap1) serves as a negative regulator of the cytoprotective transcription factor Nrf2. At basal levels, INrf2 functions as a substrate adaptor to sequester Nrf2 into the Cul3-Rbx1 E3 ligase complex for ubiquitylation and proteasomal degradation. In response to antioxidants, Nrf2 is released from the INrf2-Cul3-Rbx1 complex and translocates into the nucleus, where it activates ARE-mediated cytoprotective gene expression. The present studies demonstrate that INrf2, Cul3 and Rbx1 export out of the nucleus and are degraded during the early or pre-induction response to antioxidants. Mutation of Tyr85 in INrf2 stymied the nuclear export of INrf2, suggesting that tyrosine phosphorylation controls the pre-induction nuclear export and degradation in response to antioxidants. The nuclear export of Cul3-Rbx1 were also blocked when INrf2Tyr85 was mutated, suggesting that INrf2-Cul3-Rbx1 undergo nuclear export as a complex. INrf2 siRNA also inhibited the nuclear export of Cul3-Rbx1, confirming that Cul3-Rbx1 requires INrf2 for nuclear export. Newly synthesized INrf2-Cul3-Rbx1 is imported back into the nucleus during the post-induction period to ubiquitylate and degrade Nrf2. Mutation of INrf2Tyr85 had no effect on activation of Nrf2 but led to nuclear accumulation of Nrf2 during the post-induction period owing to reduced export and degradation of Nrf2. Our results also showed that nuclear export and degradation followed by the new synthesis of INrf2-Cul3-Rbx1 controls the cellular abundance of the proteins during different phases of antioxidant responses. In conclusion, the early or pre-induction nuclear export of INrf2 in response to antioxidants is controlled by tyrosine phosphorylation, whereas the nuclear export of Cul3 and Rbx1 is controlled by INrf2, allowing normal activation or repression of Nrf2.

Antioxidant activities and phytochemical study of leaf extracts from 18 indigenous tree species in taiwan

The objective of this study is to assess antioxidant activities of methanolic extracts from the leaves of 18 indigenous tree species in Taiwan. Results revealed that, among 18 species, Acer oliverianum exhibited the best free radical scavenging activities. The IC₅₀ values were 5.8 and 11.8 μg/mL on DPPH radical and superoxide radical scavenging activities, respectively. In addition, A. oliverianum also exhibited the strongest ferrous ion chelating activity. Based on a bioactivity-guided isolation principle, the resulting methanolic crude extracts of A. oliverianum leaves were fractionated to yield soluble fractions of hexane, EtOAc, BuOH, and water. Of these, the EtOAc fraction had the best antioxidant activity. Furthermore, 8 specific phytochemicals were isolated and identified from the EtOAc fraction. Among them, 1,2,3,4,6-O-penta-galloyl-β-D-glucopyranose had the best free radical scavenging activity. These results demonstrate that methanolic extracts and their derived phytochemicals of A. oliverianum leaves have excellent antioxidant activities and thus they have great potential as sources for natural health products.

Cytotoxicity, toxicity, and anticancer activity of Zingiber officinale Roscoe against cholangiocarcinoma

Cholangiocarcinoma (CCA) is an uncommon adenocarcinoma which arises from the epithelial cells of the bile ducts. The aim of the study was to investigate the cytotoxicity, toxicity, and anticancer activity of a crude ethanolic extract of ginger (Zingiber officinale Roscoe) against CCA. Cytotoxic activity against a CCA cell line (CL-6) was assessed by calcein-AM and Hoechst 33342 assays and anti-oxidant activity was evaluated using the DPPH assay. Investigation of apoptotic activity was performed by DNA fragmentation assay and induction of genes that may be involved in the resistance of CCA to anticancer drugs (MDR1, MRP1, MRP2, and MRP3) was examined by real-time PCR. To investigate anti-CCA activity in vivo, a total of 80 OV and nitrosamine (OV/ DMN)-induced CCA hamsters were fed with the ginger extract at doses of 1000, 3000, and 5000 mg/kg body weight daily or every alternate day for 30 days. Control groups consisting of 10 hamsters for each group were fed with 5-fluorouracil (positive control) or distilled water (untreated control). Median IC50 (concentration that inhibits cell growth by 50%) values for cytotoxicity and anti-oxidant activities of the crude ethanolic extract of ginger were 10.95, 53.15, and 27.86 μg/ml, respectively. More than ten DNA fragments were visualized and up to 7-9 fold up-regulation of MDR1 and MRP3 genes was observed following exposure to the ethanolic extract of ginger. Acute and subacute toxicity tests indicated absence of any significant toxicity at the maximum dose of 5,000 mg/kg body weight given by intragastric gavage. The survival time and survival rate of the CCA-bearing hamsters were significantly prolonged compared to the control group (median of 54 vs 17 weeks). Results from these in vitro and in vivo studies thus indicate promising anticancer activity of the crude ethanolic extract of ginger against CCA with the absence of any significant toxicity. Moreover, MDR1 and MRP3 may be involved in conferring resistance of CCA to the ginger extract.

The polymorphisms of IL-4, IL-4R and IL-13 genes and bladder cancer risk in a Chinese population: a case-control study

Accumulating evidence suggests that inflammatory process may play a role in bladder carcinogenesis. However, the exact mechanisms of how the inflammatory factors associate with bladder cancer risk are still unknown. In this study, we explored whether polymorphisms (i.e. IL-4 C-590T, IL-4R Ile50Val, IL-4R Ser478Pro, IL-4R Gln551Arg, IL-13 C-1055T and IL-13 Arg130Gln) of IL-4, IL-4R and IL-13 genes predicted Chinese bladder cancer risk in 817 bladder cancer and 1,141 controls. Genotyping was performed by using the TaqMan method. We did not find any overall association between these single nucleotide polymorphisms (SNPs) and bladder cancer susceptibility in a Chinese population. However, in the classification and regression tree (CART) analysis, we found that carriers of IL-13 C-1055T variant genotype in smokers had a 2.57-fold increased bladder cancer risk with a 55% patient rate (OR = 2.57; 95% CI = 1.93-3.43), comparing with non-smokers. Similar result was also observed in combination of IL-13 C-1055T and IL-13 Arg130Gln in smokers. By multifactor dimensionality reduction (MDR) analysis, the best interaction model was the two-factor model that smokers with the IL-13 C-1055T genotypes were the subgroup to predict bladder cancer risk. The results suggested that the genetic variants in IL-4, IL-4R and IL-13 genes might modulate the bladder cancer risk in a Chinese population.

Tissue-specific mutagenesis by N-butyl-N-(4-hydroxybutyl)nitrosamine as the basis for urothelial carcinogenesis

Bladder cancer is one of the few cancers that have been linked to carcinogens in the environment and tobacco smoke. Of the carcinogens tested in mouse chemical carcinogenesis models, N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) is one that reproducibly causes high-grade, invasive cancers in the urinary bladder, but not in any other tissues. However, the basis for such a high-level tissue-specificity has not been explored. Using mutagenesis in lacI (Big Blue™) mice, we show here that BBN is a potent mutagen and it causes high-level of mutagenesis specifically in the epithelial cells (urothelial) of the urinary bladder. After a 2-6-week treatment of 0.05% BBN in the drinking water, mutagenesis in urothelial cells of male and female mice was about two orders of magnitude greater than the spontaneous mutation background. In contrast, mutagenesis in smooth muscle cells of the urinary bladder was about five times lower than in urothelial tissue. No appreciable increase in mutagenesis was observed in kidney, ureter, liver or forestomach. In lacI (Big Blue™) rats, BBN mutagenesis was also elevated in urothelial cells, albeit not nearly as profoundly as in mice. This provides a potential explanation as to why rats are less prone than mice to the formation of aggressive form of bladder cancer induced by BBN. Our results suggest that the propensity to BBN-triggered mutagenesis of urothelial cells underlies its heightened susceptibility to this carcinogen and that mutagenesis induced by BBN represents a novel model for initiation of bladder carcinogenesis.

Chronic inhalation of biomass smoke is associated with DNA damage in airway cells: involvement of particulate pollutants and benzene

This study examined whether indoor air pollution from biomass fuel burning induces DNA damage in airway cells. For this, sputum cells were collected from 56 premenopausal rural women who cooked with biomass (wood, dung, crop residues) and 49 age-matched controls who cooked with cleaner liquefied petroleum gas. The levels of particulate matters with diameters of less than 10 and 2.5 µm (PM(10) and PM(2.5)) in indoor air were measured using a real-time aerosol monitor. Benzene exposure was monitored by measuring trans,trans-muconic acid (t,t-MA) in urine by HPLC-UV. DNA damage was examined by alkaline comet assay in sputum cells. Generation of reactive oxygen species (ROS) and level of superoxide dismutase (SOD) in sputum cells were measured by flow cytometry and spectrophotometry, respectively. Compared with controls, biomass users had 4 times higher tail percentage DNA, 37% more comet tail length and 5 times more Olive tail moment (p < 0.001) in inflammatory and epithelial cells in sputum, suggesting extensive DNA damage. In addition, women who cooked with biomass had 6 times higher levels of urinary t,t-MA and 2-fold higher levels of ROS generation concomitant with 28% depletion of SOD. Indoor air of biomass-using households had 2-4 times more PM(10) and PM(2.5) than that of controls. After controlling potential confounders, positive association was found between DNA damage parameters, particulate pollution, urinary t,t-MA and ROS. Thus, long-term exposure to biomass smoke induces DNA damage in airway cells and the effect was probably mediated, at least in part, by oxidative stress generated by inhaled particulate matter and benzene.

Anti-genotoxic potential of casein phosphopeptides (CPPs): a class of fermented milk peptides against low background radiation and prevention of cancer in radiation workers

BACKGROUND

Radiation workers are constantly exposed to low background radiation which is their occupational hazard. This continuous and prolonged exposure produces genotoxicity and cancerous condition in many workers. The authors have tested casein phosphopeptides (CPP) as a radioprotectant against low background radiation using animal models.

METHODS

Fermented milk was produced by addition of a bacterial culture, Lactobacillus acidophilus to a commercially available milk brand. After the fermentation process is completed in the milk, CPP is isolated from fermented milk by enzymatic hydrolysis-based method. The radioprotective role of CPP was proved using albino mice and Catla catla fish.

RESULTS

The micronucleus assay showed higher level of cell deformation and micronucleus formation in the control animal cells than the test animal cells. CPP has found to be having radioprotective activity potential.

CONCLUSIONS

This radioprotective potential of CPP can be harnessed to produce formulations which can be used by radiation workers and personnel exposed to low ionization background as an occupational hazard, thus reducing the risk and preventing any type of cancer.

Aldo-keto reductases protect lung adenocarcinoma cells from the acute toxicity of B[a]P-7,8-trans-dihydrodiol

Tobacco smoke exposure stimulates the expression of genes that are likely to be involved in the metabolism of its combustion products such as polycyclic aromatic hydrocarbons (PAH). Four of the smoke induced genes are aldo-keto reductases (AKR), enzymes that metabolically activate PAH to PAH o-quinones. Alternatively, PAHs are metabolized to (±)-anti-diol epoxides, such as (±)-anti-benzo[a]pyrene diol epoxide ((±)-anti-BPDE)), by the combined action of P4501A1/1B1 and epoxide hydrolase. (±)-anti-BPDE forms DNA adducts directly, while PAH o-quinones cause DNA damage by oxidative stress through a futile redox cycle. To address the role of AKRs in PAH cytotoxicity, we compared the cytotoxicity of PAH metabolites and the effects of overexpressing AKR1A1 in lung cells. (±)-anti-BPDE and B[a]P-7,8-trans-dihydrodiol, an intermediate in (±)-anti-BPDE metabolism, are toxic to A549 cells at concentrations with an IC(50) of ∼2 μM. In contrast, the PAH o-quinone B[a]P-7,8-dione was about 10-fold less toxic to A549 cells with an IC(50) > 20 μM. Similar differences in cytoxicity were observed with two other PAH o-quinones (benz[a]anthracene-3,4-dione and 7,12-dimethylbenz[a]anthracene-3,4-dione) compared with their respective diol-epoxide counterparts (BA-3,4-diol-1,2-epoxide and DMBA-3,4-diol-1,2-epoxide). In addition, both anti-BPDE and B[a]P-7,8-trans-dihydrodiol induced p53 expression ∼6 h post-treatment at concentrations as low as 1 μM consistent with extensive DNA damage. B[a]P-7,8-dione treatment did not induce p53 but generated reactive oxygen species (ROS) in A549 cells and induced the expression of oxidative response genes in H358 cells. We also observed that overexpression of AKR1A1 in H358 cells, which otherwise have low levels of AKR expression, protected cells 2-10-fold from the toxic effects of B[a]P-7,8-trans-dihydrodiol. These data suggest that overexpression of AKRs may protect lung cancer cells from the acute toxic effects of PAH.

First Steps Towards an Understanding of a Mode ofCarcinogenic Action for Vanadium Pentoxide

Inhalation of vanadium pentoxide clearly increases the incidence of alveolar/bronchiolar neoplasms in male and female B6C3F1 mice at all concentrations tested (1, 2 or 4 mg/m³), whereas responses in F344/N rats was, at most, ambiguous. While vanadium pentoxide is mutagenic in vitro and possibly in vivo in mice, this does not explain the species or site specificity of the neoplastic response. A nose-only inhalation study was conducted in female B6C3F1 mice (0, 0.25, 1 and 4 mg/m³, 6 h/day for 16 days) to explore histopathological, biochemical (α-tocopherol, glutathione and F2-isoprostane) and genetic (comet assays and 9 specific DNA-oxo-adducts) changes in the lungs. No treatment related histopathology was observed at 0.25 mg/m³. At 1 and 4 mg/m³, exposure-dependent increases were observed in lung weight, alveolar histiocytosis, sub-acute alveolitis and/or granulocytic infiltration and a generally time-dependent increased cell proliferation rate of histiocytes. Glutathione was slightly increased, whereas there were no consistent changes in α-tocopherol or 8-isoprostane F2α. There was no evidence for DNA strand breakage in lung or BAL cells, but there was an increase in 8-oxodGuo DNA lesions that could have been due to vanadium pentoxide induction of the lesions or inhibition of repair of spontaneous lesions. Thus, earlier reports of histopathological changes in the lungs after inhalation of vanadium pentoxide were confirmed, but no evidence has yet emerged for a genotoxic mode of action. Evidence is weak for oxidative stress playing any role in lung carcinogenesis at the lowest effective concentrations of vanadium pentoxide.

Evaluation of the anti-inflammatory and anti-tumor effect of Ipomoea obscura (L) and its mode of action through the inhibition of proinflammatory cytokines, nitric oxide and COX-2

Ipomoea obscura (L) is a widely used medicinal plant. In this study, we investigated its anti-inflammatory and anti-tumor effect using in vitro and in vivo models. Methanolic extract of I. obsucra (10 mg/kg b.wt) was given interaperitoneally before inducing inflammation (both acute and chronic) and tumor to mice. I. obscura produced significant inhibition of 55.6%, 42%, and 65% in the paw edema of animals induced by carrageenan, dextran, and formalin respectively. The extract was also a potent inhibitor of lipopolysaccharide (LPS)-induced NO, CRP, and proinflammatory cytokine production via gene expression in peritoneal macrophages. TNF-α production by macrophage culture treated with LPS was found to be significantly inhibited by I. obscura. The extract was 100% toxic at a concentration of 500 µg/mL for both Dalton's lymphoma ascites (DLA) and Ehrlich ascites carcinoma (EAC) cells. The extract was also found to inhibit tumor cell proliferation in a dose and time-dependent manner. It could also inhibit solid tumor development in mice induced with DLA cells and increased life span of mice bearing EAC tumor to 83% and 53.8%, respectively. This anti-inflammatory effect of the extract is assumed to result mainly from the inhibition of some key enzymes and mediators involved in the inflammation and/or cell signaling pathways such as iNOS, COX-2, and proinflammatory cytokines. This anti-inflammatory property might be the reason for its anti-tumor effects.

Preliminary study of the antioxidant properties of flowers and roots of Pyrostegia venusta (Ker Gawl) Miers

Background

Free radical stress leads to tissue injury and can eventually to arthritis, atherosclerosis, diabetes mellitus, neurodegenerative diseases and carcinogenesis. Several studies are ongoing worldwide to find natural antioxidants of plant origin. We assessed the in-vitro antioxidant activities and screened the phytochemical constituents of methanolic extracts of Pyrostegia venusta (Ker Gawl) Miers.

Methods

We evaluated the antioxidant potential and phytochemical constituents of P. venusta using 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2, 2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP) assays. Gas chromatography-mass spectroscopy (GC-MS) studies were also undertaken to assess the phytochemical composition of the flower extracts.

Results

Phytochemical analyses revealed the presence of terpenoids, alkaloids, tannins, steroids, and saponins. The reducing ability of both extracts was in the range (in μm Fe(II)/g) of 112.49-3046.98 compared with butylated hydroxytoluene (BHT; 63.56 ± 2.62), catechin (972.02 ± 0.72 μm) and quercetin 3208.27 ± 31.29. A significant inhibitory effect of extracts of flowers (IC₅₀ = 0.018 ± 0.69 mg/ml) and roots (IC₅₀ = 0.026 ± 0.94 mg/ml) on ABTS free radicals was detected. The antioxidant activity of the extracts of flowers (95%) and roots (94%) on DPPH radicals was comparable with that of ascorbic acid (98.9%) and BHT (97.6%). GC-MS study revealed the presence of myoinositol, hexadecanoic acid, linoleic acid, palmitic acid and oleic acid in the flower extracts.

Conclusion

These data suggest that P. venusta is a natural source of antioxidants. The extracts of flowers and roots of P. venusta contain significant amounts of phytochemicals with antioxidative properties and could serve as inhibitors or scavengers of free radicals. P. venusta could be exploited as a potential source for plant-based pharmaceutical products. These results could form a sound basis for further investigation in the potential discovery of new natural bioactive compounds.

RNA silencing: Mechanism, biology and responses to environmental stress

Much early work on environmental stress, including ionizing radiation and environmental toxins, emphasised their action on DNA and subsequent mutagenesis in long term effects including germ cell mutagenesis, carcinogenesis and trans-generational effect. However, recent studies are increasingly pointing a complementary role of epigenetic effects in these processes. While a substantial part of the literature focuses on DNA methylation, there is increasing recognition of the role of non-coding RNAs, including small-, micro-, and pi-RNAs, as well as transposable elements. These play key roles in carcinogenesis, and in germ cell changes including trans-generational effects.

Red wine: A drink to your heart

Mortality and morbidity are still high in cardiovascular disease (CVD). Myocardial ischemia reperfusion injury leading to myocardial infarction is one of the most frequent causes of the death in humans. Atherosclerosis and generation of reactive oxygen species through oxidative stress is the major risk factor for CVD. From the literature collection, it has been identified that moderate consumption of red wine helps in preventing CVD through several mechanisms, including increasing the high-density lipoprotein cholesterol plasma levels, decreasing platelet aggregation, by antioxidant effects, and by restoration of endothelial function. The aim of this review is to discuss the accumulating evidence that suggests that red wine possesses a diverse range of biological actions and may be beneficial in the prevention of CVD.

Model for in vivo progression of tumors based on co-evolving cell population and vasculature

With countless biological details emerging from cancer experiments, there is a growing need for minimal mathematical models which simultaneously advance our understanding of single tumors and metastasis, provide patient-personalized predictions, whilst avoiding excessive hard-to-measure input parameters which complicate simulation, analysis and interpretation. Here we present a model built around a co-evolving resource network and cell population, yielding good agreement with primary tumors in a murine mammary cell line EMT6-HER2 model in BALB/c mice and with clinical metastasis data. Seeding data about the tumor and its vasculature from in vivo images, our model predicts corridors of future tumor growth behavior and intervention response. A scaling relation enables the estimation of a tumor's most likely evolution and pinpoints specific target sites to control growth. Our findings suggest that the clinically separate phenomena of individual tumor growth and metastasis can be viewed as mathematical copies of each other differentiated only by network structure.

CCAAT/enhancer-binding protein delta mediates tumor necrosis factor alpha-induced Aurora kinase C transcription and promotes genomic instability

Epidemiologic and clinical research indicates that chronic inflammation increases the risk of certain cancers, possibly through chromosomal instability. However, the mechanism of inflammation-dependent chromosomal instability associated with tumorigenesis is not well characterized. The transcription factor CCAAT/enhancer-binding protein δ (C/EBPδ, CEBPD) is induced by tumor necrosis factor α (TNFα) and expressed in chronically inflamed tissue. In this study, we show that TNFα promotes aneuploidy. Loss of CEBPD attenuated TNFα-induced aneuploidy, and CEBPD caused centromere abnormality. Additionally, TNFα-induced CEBPD expression augmented anchorage-independent growth. We found that TNFα induced expression of aurora kinase C (AURKC) through CEBPD, and that AURKC also causes aneuploidy. Furthermore, high CEBPD expression correlated with AURKC expression in inflamed cervical tissue specimens. These data provide insight into a novel function for CEBPD in inducing genomic instability through the activation of AURKC expression in response to inflammatory signals.

Neoplastic disorders of prostate glands in the light of synchrotron radiation and multivariate statistical analysis

The prostate gland is the most common site of neoplastic disorders in men. The pathogenesis of inflammatory cells, prostatic intraepithelial neoplasia (PIN) lesions, and prostate cancer is still under investigation. Inflammatory cells by producing free radicals are considered as major and universal contributors to cancerogenesis. PIN is regarded as a precursor lesion to prostate cancer or a marker signaling the vulnerability of the epithelium to neoplastic transformation [1]. Differentiation markers that are frequently changed in early invasive carcinoma are also changed in PIN lesions. In this study, prostate tissue samples obtained during surgical operation and classified as various disease states (inflammation, PIN lesions, and cancer) were examined. The samples were measured by means of microbeam synchrotron-radiation-induced X-ray emission (micro-SRIXE). Special attention was paid to examine the relationship between the earlier-mentioned disorders and changes in relative concentrations of S, K, Ca, Fe, Cu, and Zn. Applying the image-processing program ImageJ enabled us to select the areas of interest from two-dimensional maps of various prostate samples according to the histopathologist's evaluation. Detailed analysis of micro-SRIXE spectra based on multivariate methods shows significant differences between elemental concentrations in inflammatory cells, PIN lesions, and cancerous tissues, which confirms that this method can be used to distinguish various pathological states in prostate tissues. Information obtained in this way may provide better understanding of the biochemistry of unhealthy prostate tissues, thus opening the way to find new medicines/treatments to prevent or slow down some harmful intracellular processes.

Polonium and lung cancer

The alpha-radioactive polonium 210 (Po-210) is one of the most powerful carcinogenic agents of tobacco smoke and is responsible for the histotype shift of lung cancer from squamous cell type to adenocarcinoma. According to several studies, the principal source of Po-210 is the fertilizers used in tobacco plants, which are rich in polyphosphates containing radio (Ra-226) and its decay products, lead 210 (Pb-210) and Po-210. Tobacco leaves accumulate Pb-210 and Po-210 through their trichomes, and Pb-210 decays into Po-210 over time. With the combustion of the cigarette smoke becomes radioactive and Pb-210 and Po-210 reach the bronchopulmonary apparatus, especially in bifurcations of segmental bronchi. In this place, combined with other agents, it will manifest its carcinogenic activity, especially in patients with compromised mucous-ciliary clearance. Various studies have confirmed that the radiological risk from Po-210 in a smoker of 20 cigarettes per day for a year is equivalent to the one deriving from 300 chest X-rays, with an autonomous oncogenic capability of 4 lung cancers per 10000 smokers. Po-210 can also be found in passive smoke, since part of Po-210 spreads in the surrounding environment during tobacco combustion. Tobacco manufacturers have been aware of the alpha-radioactivity presence in tobacco smoke since the sixties.

Acute reduction of serum 8-iso-PGF2-alpha and advanced oxidation protein products in vivo by a polyphenol-rich beverage; a pilot clinical study with phytochemical and in vitro antioxidant characterization

Background

Measuring the effects of the acute intake of natural products on human biomarker concentrations, such as those related to oxidation and inflammation, can be an advantageous strategy for early clinical research on an ingredient or product.

Methods

31 total healthy subjects were randomized in a double-blinded, placebo-controlled, acute pilot study with post-hoc subgroup analysis on 20 of the subjects. The study examined the effects of a single dose of a polyphenol-rich beverage (PRB), commercially marketed as "SoZo^®", on serum anti-inflammatory and antioxidant markers. In addition, phytochemical analyses of PRB, and in vitro antioxidant capacity were also performed.

Results

At 1 hour post-intake, serum values for 8-iso-PGF2-alpha and advanced oxidation protein products decreased significantly by 40% and 39%, respectively. Additionally, there was a trend toward decreased C-reactive protein, and increased nitric oxide levels. Both placebo and PRB treatment resulted in statistically significant increases in hydroxyl radical antioxidant capacity (HORAC) compared to baseline; PRB showed a higher percent change (55-75% versus 23-74% in placebo group), but the two groups did not differ significantly from each other.

Conclusions

PRB produced statistically significant changes in several blood biomarkers related to antioxidant/anti-inflammatory effects. Future studies are justified to verify results and test for cumulative effects of repeated intakes of PRB. The study demonstrates the potential utility of acute biomarker measurements for evaluating antioxidant/anti-inflammatory effects of natural products.

The simple and sensitive measurement of malondialdehyde in selected specimens of biological origin and some feed by reversed phase high performance liquid chromatography

A method for the determination of malondialdehyde (MDA) concentrations in specimens of animal tissues and feed has been developed using high performance liquid chromatography. The MDA concentration in acidified urine samples was determined after its conversion with 2,4-dinitrophenylhydrazine (DNPH) to a hydrazone (MDA-DNPH). Samples of blood plasma, muscle, liver and feed were prepared by saponification followed by derivatisation with DNPH to MDA-DNPH. The MDA concentration in chicken and hen feed samples was analysed after saponification and derivatisation followed by extractions with hexane. The free MDA in plasma samples was determined after deproteinization followed by derivatisation of MDA with DNPH. The chromatographic separation of MDA-DNPH samples was conducted using Phenomenex C(18)-columns (Synergi 2.5 μm, Hydro-RP, 100 Å, the length of 100mm) with an inner diameter of 2 or 3mm. MDA in processed biological samples was analysed using a linear gradient of acetonitrile in water, and the photodiode detector was set to 307 or 303 nm for detection. The current method that was utilised was based on the high-efficient derivatisation of MDA and was more sensitive compared to previously used methods. The selective and sensitive photodetection of the column effluent was found to be suitable for the routine analysis of MDA in urine, plasma, muscles and liver of animals and some feed samples. Because urine or blood plasma samples can be derivatised in a simple manner, the proposed method can also be suitable for the routine, non-invasive evaluation of oxidative stress in animals and humans.

In vitro antioxidant activity of Bombax malabaricum flower extracts

CONTEXT

Bombax malabaricum DC. (Bombacaceae) is a traditional Chinese herbal medicine used for the treatment of inflammatory conditions, diarrhea, fever, chronic inflammation, catarrhal affection, and as a diuretic. However, little information is available about its antioxidative activity.

OBJECTIVE

Water, 50% ethanol, and 80% acetone extracts from flowers of B. malabaricum were investigated for their in vitro antioxidant activity in this article for the first time. Then the relationships between antioxidant activity measured by different methods and total phenolic content (TPC) and total flavonoid content (TFC) were established.

MATERIALS AND METHODS

The antioxidant activities of extracts from B. malabaricum flower were investigated including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, oxygen radical absorbance capacity (ORAC), reducing power, and inhibition on phosphatidylcholine liposome peroxidation.

RESULTS

Results showed that all the extracts possessed remarkable antioxidant capacity compared with ascorbic or gallic acids. Total antioxidant activities evaluated by ORAC assay of different extracts ranged from 700.03 to 1482.46 μmol Trolox equivalents/g. The highest TPC of 130.38 mg gallic acid equivalents (GAE)/g was observed in 80% acetone extract, whereas the lowest TPC of 57.09 mg GAE/g was obtained in the water extract. Furthermore, TFC exhibited significant (P < 0.05) positive correlations with DPPH radical-scavenging activity, ORAC, and reducing power.

DISCUSSION AND CONCLUSION

These findings demonstrate that the flowers of B. malabaricum have excellent antioxidant activities and thus might be a potential source of natural antioxidants.

Molecular mechanisms of cigarette smoke-induced proliferation of lung cells and prevention by vitamin C

Lung cancer is the leading cause of cancer dearth. Cigarette smoking is the strongest risk factor for developing lung cancer, which is conceivably initiated by proliferation. Here, we show that low concentration of aqueous extract of cigarette smoke (AECS) causes excessive proliferation of human lung epithelial cells (A549) without any apoptotic cell death. The causative factor responsible for AECS-induced proliferation has been identified as p-benzoquinone (p-BQ). Coimmunoprecipitation and immunoblot experiments indicate that p-BQ binds with epidermal growth factor receptor (EGFR). However, in contrast to EGF, it causes aberrant phosphorylation of EGFR that lacks c-Cbl-mediated ubiquitination and degradation resulting in persistent activation of EGFR. This is followed by activation of Hras + Kras and the downstream survival and proliferative signaling molecules Akt and ERK1/2, as well as the nuclear transcription factors c-Myc and c-Fos. Vitamin C and/or antibody to p-BQ prevents AECS/p-BQ-induced proliferation of lung cells apparently by inactivating p-BQ and thereby preventing activation of EGFR and the downstream signaling molecules. The results suggest that vitamin C and/or antibody to p-BQ may provide a novel intervention for preventing initiation of lung cancer in smokers.

Lycopene enhances antioxidant enzyme activities and immunity function in N-methyl-N'-nitro-N-nitrosoguanidine-enduced gastric cancer rats

To investigate anticancer effect of lycopene, we examined the effects of lycopene on the oxidative injury and immunity activities of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced gastric cancer rats. The animals were divided into five groups. Group I served as the normal control and was given corn oil orally for 20 weeks. Group II were induced with MNNG 200 mg/kg body weight by oral gavage at days 0 and 14, and saturated NaCl (1 mL per rats) was given once every three days for four weeks until the end of the experimental period. Group III, IV and V were posttreated with lycopene (50, 100 and 150 mg/kg body weight, dissolved in corn oil) from the sixth week of MNNG (as in group II) induction up to the end of the experimental period. In the presence of MNNG, MDA and immunity levels were significantly increased, whereas enzymatic (SOD, CAT, and GPx) antioxidant activities were decreased in the treated rats compared with normal control rats. Administration of lycopene to gastric carcinoma-induced rats largely up-regulated the redox status and immunity activities to decrease the risk of cancer compared to group II. We conclude that up-regulation of antioxidants and immunity by lycopene treatment might be responsible for the anticancer effect in gastric carcinoma.

Tomato lycopene and lung cancer prevention: from experimental to human studies

Increasing evidence suggests that tomato lycopene may be preventive against the formation and the development of lung cancer. Experimental studies demonstrated that lycopene may inhibit the growth of several cultured lung cancer cells and prevent lung tumorigenesis in animal models through various mechanisms, including a modulation of redox status, cell cycle arrest and/or apoptosis induction, a regulation of growth factor signaling, changes in cell growth-related enzymes, an enhancement of gap junction communication and a prevention of smoke-induced inflammation. In addition, lycopene also inhibited cell invasion, angiogenesis, and metastasis. Several lycopene metabolites have been identified, raising the question as to whether the preventive effects of lycopene on cancer risk is, at least in part, due to its metabolites. Despite these promising reports, it is difficult at the moment to directly relate available experimental data to human pathophysiology. More well controlled clinical intervention trials are needed to further clarify the exact role of lycopene in the prevention of lung cancer cell growth. Such studies should take into consideration subject selection, specific markers of analysis, the levels of carotenoids being tested, metabolism and isomerization of lycopene, interaction with other bioactive food components. This article reviews data on the cancer preventive activities of lycopene, possible mechanisms involved, and the relationship between lycopene consumption and human cancer risk.

Comparison and characterization of the antioxidant potential of 3 wild grapes--Vitis thunbergii, V. flexuosa, and V. kelungeusis

This study considers a laboratory examination of the antioxidant performance of methanolic extracts from the leaves and stems of 3 common wild grapes (Vitis thunbergii, V. flexuosa, and V. kelungeusis) by various in vitro methods. It also seeks to identify the specific antioxidant constituent. Results revealed that, of these specimens, stem extracts of V. thunbergii exhibited good 1,1-diphenyl-2-picrylhydrazyl radical-scavenging and superoxide radical-scavenging performance and ferrous ion-chelating ability, as well as the highest total phenolic content (179.5 mg of GAE/g). The principal antioxidant, (+)-lyoniresinol-2a-O-β-D-glucopyranoside, was isolated from the stem extracts of V. thunbergii and identified. Removal of this compound from the extracts caused an approximate 2- to 5-fold decrease in antioxidant performance. This showed that (+)-lyoniresinol-2a-O-β-D-glucopyranoside is the primary antioxidant in wild grapes. Results also indicated that the antioxidant performance of (+)-lyoniresinol-2a-O-β-D-glucopyranoside was stronger than its lignan aglycone, (+)-lyoniresinol.

PRACTICAL APPLICATION

Of the 3 common wild grapes-Vitis thunbergii, V. flexuosa, and V. kelungeusis, the extracts or phytochemicals, derived from the V. thunbergii stems have excellent antioxidant properties, so they have great potential as a basis for natural health products that seek to prevent diseases caused by the overproduction of radicals.

Effects of high hydrostatic pressure (HHP) on bioaccessibility, as well as antioxidant activity, mineral and starch contents in Granny Smith apple

The aim of this work was to study the effect of high hydrostatic pressure on the bioaccessibility of specific nutrients (antioxidant, minerals and starch) in apple and to establish processing conditions that maximise the health benefits. The apple was pressurised at 500MPa during 2, 4, 8 and 10min. The antioxidant activity, mineral and starch content and bioaccessibility of apple samples were significantly affected by the processing and digestion conditions. Therefore, these results indicated that in vitro digestion has a noticeable effect on the antioxidant concentration, IC50, with much lower values (a smaller IC50 value corresponds to a higher antioxidant activity) of apple samples compared with those untreated and non-digestion. Apple has the highest calcium content (30.33±1.94mg/100g), iron (14.46±3.49mg/100g) and zinc (6.22±0.91mg/100g). High hydrostatic pressure increased the mineral contents availability by 2.11-303.00% for calcium, 4.63-10.93% for iron and 8.68-28.93% for zinc. The dialysability and solubility of calcium, iron and zinc with respect to the values for the untreated sample were reduced by this high pressure technique. Consumption of apple under high hydrostatic pressure may supply substantial antioxidants, mineral and starch, which may provide health promoting and disease preventing effects.

Lycopene inhibits DNA damage and reduces hMTH1 mRNA expression in the liver of Mongolian gerbils treated with ferric nitrilotriacetate

Epidemiologic studies suggest that lycopene may reduce the risk of certain cancers, but the underlying mechanisms are unclear. We hereby examined in vivo anticarcinogenic effects of supplemental lycopene on hepatic DNA damage (Comet formation and levels of 8-oxo-2'-deoxyguanosine, 8-oxo-dG) and human MutT homologue (hMTH1) mRNA expression in Mongolian gerbils injected i.p. with ferric nitrilotriacetate (Fe/NTA). Gerbils were pre-treated with two dose (10 and 20 mg/kg BW) of lycopene on alternate morning for 10 d. Six hours after the last lycopene supplementation, the gerbils received Fe/NTA (0.16 mmol/10 mL/kg BW) and were killed 3 h later. We found that the livers of Fe/NTA-treated animals exhibited a 5-fold increase in Comet formation (expressed as tail moment), a 2.6-fold increase in 8-oxo-dG levels and a significant increase in hMTH1 mRNA expression. Supplemental lycopene completely inhibited Comet formation (P<0.001) and significantly suppressed 8-oxo-dG levels and hMTH1 expression in a dose-dependent manner. The expression levels of hMTH1 mRNA are highly correlated with hepatic levels of 8-oxo-dG and tail moment, suggesting that hMTH1 gene expression represents a molecular marker of oxidative DNA damage. These results demonstrate the potential of lycopene as a promising chemopreventive agent against hepatotumorigenesis.

Glutathione in cancer cell death

Glutathione (L-γ-glutamyl-L-cysteinyl-glycine; GSH) in cancer cells is particularly relevant in the regulation of carcinogenic mechanisms; sensitivity against cytotoxic drugs, ionizing radiations, and some cytokines; DNA synthesis; and cell proliferation and death. The intracellular thiol redox state (controlled by GSH) is one of the endogenous effectors involved in regulating the mitochondrial permeability transition pore complex and, in consequence, thiol oxidation can be a causal factor in the mitochondrion-based mechanism that leads to cell death. Nevertheless GSH depletion is a common feature not only of apoptosis but also of other types of cell death. Indeed rates of GSH synthesis and fluxes regulate its levels in cellular compartments, and potentially influence switches among different mechanisms of death. How changes in gene expression, post-translational modifications of proteins, and signaling cascades are implicated will be discussed. Furthermore, this review will finally analyze whether GSH depletion may facilitate cancer cell death under in vivo conditions, and how this can be applied to cancer therapy.

Identification of clinically relevant protein targets in prostate cancer with 2D-DIGE coupled mass spectrometry and systems biology network platform

Prostate cancer (PCa) is the most common type of cancer found in men and among the leading causes of cancer death in the western world. In the present study, we compared the individual protein expression patterns from histologically characterized PCa and the surrounding benign tissue obtained by manual micro dissection using highly sensitive two-dimensional differential gel electrophoresis (2D-DIGE) coupled with mass spectrometry. Proteomic data revealed 118 protein spots to be differentially expressed in cancer (n = 24) compared to benign (n = 21) prostate tissue. These spots were analysed by MALDI-TOF-MS/MS and 79 different proteins were identified. Using principal component analysis we could clearly separate tumor and normal tissue and two distinct tumor groups based on the protein expression pattern. By using a systems biology approach, we could map many of these proteins both into major pathways involved in PCa progression as well as into a group of potential diagnostic and/or prognostic markers. Due to complexity of the highly interconnected shortest pathway network, the functional sub networks revealed some of the potential candidate biomarker proteins for further validation. By using a systems biology approach, our study revealed novel proteins and molecular networks with altered expression in PCa. Further functional validation of individual proteins is ongoing and might provide new insights in PCa progression potentially leading to the design of novel diagnostic and therapeutic strategies.