Diet and cancer prevention

The surgeon's role in cancer prevention. The model in colorectal carcinoma

Cancer Prevention is an emerging field, capturing the old traditional concept of anticipating the development of a major disease and preventing its full impact by early detection, treatment, or aborting the tumorigenic process by a "molecular vaccine" and alleviating the full impact of the disease. Surgeons are important clinician scientists who can carry this discipline forward and develop its full potential in the clinics and in the community. Advances in molecular biology, genetics, and other technologies have permitted seminal understanding of the carcinogenic pathways and identification of targets and intermediate end points in neoplasia. In this review, we will see that we have the means of preventing significant numbers of colorectal carcinomas (CRC).

Concentration-dependent effects of genistein on global gene expression in MCF-7 breast cancer cells: an oligo microarray study

Breast cancer is the most commonly diagnosed cancer among US women; there is therefore great interest in developing preventive and treatment strategies for this disease. Because breast cancer incidence is much lower in countries where women consume high levels of soy, bioactive compounds in this food source have been studied for their effects on breast cancer. Genistein, found at high levels in soybeans and soy foods, is a controversial candidate breast cancer preventive phytochemical whose effects on breast cells are complex. To understand more clearly the molecular mechanisms underlying the effects of genistein on breast cancer cells, we used a DNA oligo microarray approach to examine the global gene expression patterns in MCF-7 breast cancer cells at both physiologic (1 or 5 microM) and pharmacologic (25 microM) genistein concentrations. Microarray analyses were performed on MCF-7 cells after 48 h of either vehicle or 1, 5, or 25 microM genistein treatment. We found that genistein altered the expression of genes belonging to a wide range of pathways, including estrogen- and p53-mediated pathways. At 1 and 5 microM, genistein elicited an expression pattern suggestive of increased mitogenic activity, confirming the proliferative response to genistein observed in cultured MCF-7 cells, while at 25 microM genistein effected a pattern that likely contributes to increased apoptosis, decreased proliferation and decreased total cell number, also consistent with cell culture results. These findings provide evidence for a molecular signature of genistein's effects in MCF-7 cells and lay the foundation for elucidating the mechanisms of genistein's biological impact in breast cancer cells.

Effects of phenylethyl isothiocyanate on early molecular events in N-nitrosomethylbenzylamine-induced cytotoxicity in rat esophagus

There is little information on early molecular events in the development of N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis and of the effects of chemopreventive agents on these events. In this study, we identified genes in rat esophagus that were differentially expressed in response to short-term NMBA treatment and modulated by cotreatment with phenylethyl isothiocyanate (PEITC). Rats were fed AIN-76A diet or AIN-76A diet containing PEITC for 3 weeks. During the 3rd week of dietary treatment, they were administered three s.c. doses of NMBA (0.5 mg/kg body weight). Rats were sacrificed 24 h after the last treatment; esophagi were excised and processed for histologic grading, microarray and real-time PCR analysis. Histopathologic analysis showed that treatment of rats with PEITC had a protective effect on NMBA-induced preneoplastic lesions in the rat esophagus. We identified 2,261 genes that were differentially expressed in the NMBA-treated versus control esophagi and 1,936 genes in the PEITC + NMBA versus NMBA-treated esophagi. The intersection of these two sets resulted in the identification of 1,323 genes in NMBA-treated esophagus, the vast majority of which were modulated by PEITC to near-normal levels of expression. Measured changes in the expression levels of eight selected genes were validated using real-time PCR. Results from 12 microarrays indicated that PEITC treatment had a genome-wide modulating effect on NMBA-induced gene expression. Samples obtained from animals treated with PEITC alone or cotreated with PEITC + NMBA were more similar to controls than to samples treated with NMBA alone.

Food, nutrient and heterocyclic amine intake and the risk of bladder cancer

Fruit and vegetable intake has been linked to bladder cancer risk; however, evidence for other foods or specific dietary factors is inconclusive. The association between diet and bladder cancer risk was evaluated among 912 incident bladder cancer cases and 873 controls in Spain. Data were consistent with a reduced bladder cancer risk associated with high fruit intake; however, the association was significant only among current smokers (OR (95% CI) for 5th versus 1st quintile: 0.5 (0.3-0.9), p trend=0.009). Evaluation of food subgroups showed significant inverse associations with high intakes of berries, Liliaceae vegetables and yellow-orange vegetables. The latter association was stronger among individuals with the GSTM1 present than the null genotype (0.4 (0.2, 0.7) and 0.9 (0.6, 1.3), respectively; p for interaction=0.04). Meat or fish intake, their cooking methods or level of doneness, or heterocyclic amine intakes were not significantly associated with risk. Intake of folate, other B-vitamins (B12, B6, B2) and retinol was also associated with a reduced risk, the strongest associations being for vitamin B6 (0.6 (0.4, 0.8) p trend=0.0006) and retinol (0.6 (0.4-0.9) p trend=0.004). Our findings indicate that fruit and vegetable intake, as well as B-vitamin and retinol intake might be associated with a reduced bladder cancer risk.

The potential of nuts in the prevention of cancer

Cancer is a disease that is characterized by the loss of genetic control over cell growth and proliferation, mainly as a result of the exposure to environmental factors. Cessation of smoking and a high consumption of fruits and vegetables are the most important means of reducing the risk of cancer in our society. Like fruits and vegetables, nuts are a source of vegetable protein, monounsaturated fatty acids, vitamin E, phenolic compounds, selenium, vegetable fibre, folic acid and phytoestrogens. There are numerous mechanisms of action by which these components can intervene in the prevention of cancer, although they have not been fully elucidated. There are very few epidemiological studies analyzing the relationship between nuts consumption and risk of cancer. One of the greatest difficulties in interpreting the results is that the consumption of nuts, seeds and legumes are often presented together. The most commonly studied location is the colon/rectum, an organ in which the effect of nuts is biologically plausible. Although the results are not conclusive, a protective effect on colon and rectum cancer is possible. Likewise, some studies show a possible protective effect on prostate cancer, but there is insufficient data on other tumour locations. New epidemiological studies are required to clarify the possible effects of nuts on cancer, particularly prospective studies that make reliable and complete estimations of their consumption and which make it possible to analyse their effects independently of the consumption of legumes and seeds.

Strategies for cancer prevention: the role of diet

Linkages between diet habits and cancer risk have surfaced from a multitude of epidemiological and preclinical studies. Collectively these studies provide rather compelling evidence that dietary components modify the incidence and biological behavior of tumors. While the risk of breast, prostate, colon, lung and liver cancers are frequently associated with dietary patterns, inconsistencies are not uncommon. These inconsistencies likely reflect the multi-factorial and complex nature of cancer and the specificity that individual dietary constituents have in modifying cancer related genetic pathways. The complexity of defining the role of diet is underscored by the numerous and diverse essential and non-essential components that may alter one or more phases of the cancer process. The explosive increase in the recognition of genes and pathways for regulating cell growth and development, and evaluating the response to hormones and other chemicals synthesized by the body, offers exciting opportunities for unraveling the molecular targets by which dietary components influence cancer prevention. It is recognized that all cells have unique ‘signatures’ that are characterized by active and inactive genes and cellular products. It is certainly plausible that bridging knowledge about these unique cellular characteristics with the molecular targets for nutrients can be used to assist in optimizing nutrition and minimizing cancer risk.

Medicinal importance of fungal beta-(1-->3), (1-->6)-glucans

Non-cellulosic beta-glucans are now recognized as potent immunological activators, and some are used clinically in China and Japan. These beta-glucans consist of a backbone of glucose residues linked by beta-(1-->3)-glycosidic bonds, often with attached side-chain glucose residues joined by beta-(1-->6) linkages. The frequency of branching varies. The literature suggests beta-glucans are effective in treating diseases like cancer, a range of microbial infections, hypercholesterolaemia, and diabetes. Their mechanisms of action involve them being recognized as non-self molecules, so the immune system is stimulated by their presence. Several receptors have been identified, which include: dectin-1, located on macrophages, which mediates beta-glucan activation of phagocytosis and production of cytokines, a response co-ordinated by the toll-like receptor-2. Activated complement receptors on natural killer cells, neutrophils, and lymphocytes, may also be associated with tumour cytotoxicity. Two other receptors, scavenger and lactosylceramide, bind beta-glucans and mediate a series of signal pathways leading to immunological activation. Structurally different beta-glucans appear to have different affinities toward these receptors and thus generate markedly different host responses. However, the published data are not always easy to interpret as many of the earlier studies used crude beta-glucan preparations with, for the most part, unknown chemical structures. Careful choice of beta-glucan products is essential if their benefits are to be optimized, and a better understanding of how beta-glucans bind to receptors should enable more efficient use of their biological activities.

Behavioural, attitudinal and dietary responses to the consumption of wholegrain foods

Whole grains are important dietary constituents as they provide a plethora of nutrients and protective chemicals that may have synergistic actions in promoting health. Regular consumption of wholegrain foods has been associated with a reduced risk of several chronic diseases such as CHD and certain cancers, although their exact role in disease prevention is not yet fully elucidated. Studies reporting levels of whole grain consumption reveal that those subjects who include higher levels of whole grain foods in their diets also have many other favourable dietary and lifestyle practices. While the actions of these practices and whole grains may not be mutually exclusive, these variables do not appear to explain the reduction in risk of disease observed for high-whole grain consumers. Actual whole grain consumption levels are extremely low and many practical barriers exist to consumer uptake of these foods. Effective communication of the whole grain health message is an important strategy to increase awareness of the importance of whole grains in the diet. Increasing the variety and availability of acceptable wholegrain foods is also important. Whole grain consumption at breakfast can have an important impact on total daily nutrient intakes. This simple dietary modification is potentially relatively easy to achieve and could greatly contribute to increased whole grain intake for many individuals.

Determination of polyacetylenes in carrot roots (Daucus carotaL.) by high-performance liquid chromatography coupled with diode array detection

A new high-performance liquid chromatographic method with diode array detection was developed for the separation and simultaneous determination of the carrot polyacetylenes falcarindiol (FaDOH), falcarindiol 3-acetate (FaDOAc) and falcarinol (FaOH) in carrot root extracts. The optimal chromatographic conditions were achieved on a C18 column with a linear gradient elution of water and acetonitrile as mobile phases, at the flow rate of 1.0 mL/min. All calibration curves of the three carrot polyacetylenes showed good linear regression (R2 > 0.998) within the test ranges. The developed method showed good precision for quantification of all polyacetylenes with overall intraday and interday variation of less than 3.3% and with average recovery rates of 99.2, 96.8 and 99.7% for FaDOH, FaDOAc and FaOH, respectively. The LOD (S/N = 3) and LOQ (S/N = 10) were less than 0.19 and 0.42 microg/mL, respectively, for all analytes. The established method was successfully used to determine the spatial distribution of FaDOH, FaDOAc and FaOH in six carrot genotypes (Bolero, Independent, Line 1, Mello Yello, Purple Haze and Tornado) by analysing peeled carrots and the corresponding peels for these polyacetylenes.

Anthocyanidins inhibit migration of glioblastoma cells: structure-activity relationship and involvement of the plasminolytic system

Complete resection of malignant glioblastomas is usually impossible because of diffuse and widespread invasion of tumor cells, and complementary approaches need to be developed in order to improve the efficacy of current treatments. Consumption of fruits and berries has been associated with decreased risk of developing cancer and there is great interest in the use of molecules from dietary origin to improve anticancer therapies. In this work, we report that the aglycons of the most abundant anthocyanins in fruits, cyanidin (Cy), delphinidin (Dp), and petunidin (Pt), act as potent inhibitors of glioblastoma cell migration. Dp clearly exhibited the highest inhibitory potency, this effect being related to the ortho-dihydroxyphenyl structure on the B-ring and the presence of a free hydroxyl group at position 3. Dp decreases the expression of both urokinase-type plasminogen activator receptor (uPAR) and the low-density lipoprotein receptor-related protein (LRP), acting at the transcriptional levels. In addition, Dp upregulated urokinase-type plasminogen activator (uPA) and downregulated the plasminogen activator inhibitor-1 (PAI-1) but decreased, in a concentration-dependent manner, the uPA-dependent conversion of plasminogen to plasmin, indicating that the upregulation of uPA observed with these compounds was not associated with induction of the plasminolytic activity. Overall, these results demonstrate that Dp, Pt, and Cy affect plasminogen activation, thus leading to the inhibition of glioblastoma cell migration and therefore they may be helpful for the development of new strategies for cancer prevention and therapy.

Molecular signatures of soy-derived phytochemicals in androgen-responsive prostate cancer cells: a comparison study using DNA microarray

The present study utilized microarray technology as a tool to elucidate the molecular signatures of soy-derived phytochemicals in the human androgen-responsive prostate cancer cell line LNCaP. Global gene expression pattern analysis of LNCaP cells exposed to 0, 1, 5, or 25 microM of the soy-derived phytochemicals equol and daidzein were conducted and compared. The data were further compared with previously generated data from exposure of LNCaP cells to the same doses of genistein, a soy isoflavone. Multidimensional scaling (MDS) analyses of the expression patterns suggest that these compounds exerted differential effects on gene expression in LNCaP cells. Further examination of specific gene changes revealed that these compounds differentially modulated genes in multiple cellular pathways, including the cell-cycle pathway genes. However, the three compounds also exerted similar effect on genes belonging to several other important cellular pathways. A universal effect of the three compounds on androgen-responsive genes, IGF-1 pathway gene, and MAP kinase-related pathway gene was observed. These results provide the foundation for establishing molecular signatures for equol, daidzein, and genistein. Moreover, these results also allow for the identification of candidate mechanism(s) by which soy phytochemicals and soy may act in prostate cancer cells.

Contributions of Ernst L. Wynder to chronic disease control worldwide and to preventive medicine

Ernst L. Wynder is internationally known for his important discoveries in the field of human chronic disease causation, that is the underlying mechanisms, studied in various animal models, as a foundation for recommendations on the prevention of these diseases. These include coronary heart disease, and the main human cancers including cancer of the lung, caused by traditional smoking habits, and the nutritionally linked cancers, namely cancer of the breast, prostate, colon, pancreas, and urinary bladder. Much of this research was performed in a chronic disease prevention institution--created by Dr. Wynder--the American Health Foundation. There were outreach programs to educate people about proper lifestyles to secure disease prevention, including beginning health education in children.

Induction of cell cycle changes and modulation of apoptogenic/anti-apoptotic and extracellular signaling regulatory protein expression by water extracts of I'm-Yunity (PSP)

Background

I'm-Yunity™ (PSP) is a mushroom extract derived from deep-layer cultivated mycelia of the patented Cov-1 strain of Coriolus versicolor (CV), which contains as its main bioactive ingredient a family of polysaccharo-peptide with heterogeneous charge properties and molecular sizes. I'm-Yunity™ (PSP) is used as a dietary supplement by cancer patients and by individuals diagnosed with various chronic diseases. Laboratory studies have shown that I'm-Yunity™ (PSP) enhances immune functions and also modulates cellular responses to external challenges. Recently, I'm-Yunity™ (PSP) was also reported to exert potent anti-tumorigenic effects, evident by suppression of cell proliferation and induction of apoptosis in malignant cells. We investigate the mechanisms by which I'm-Yunity™ (PSP) elicits these effects.

Methods

Human leukemia HL-60 and U-937 cells were incubated with increasing doses of aqueous extracts of I'm-Yunity™ (PSP). Control and treated cells were harvested at various times and analyzed for changes in: (1) cell proliferation and viability, (2) cell cycle phase transition, (3) induction of apoptosis, (4) expression of cell cycle, apoptogenic/anti-apoptotic, and extracellular regulatory proteins.

Results

Aqueous extracts of I'm-Yunity™ (PSP) inhibited cell proliferation and induced apoptosis in HL-60 and U-937 cells, accompanied by a cell type-dependent disruption of the G₁/S and G₂/M phases of cell cycle progression. A more pronounced growth suppression was observed in treated HL-60 cells, which was correlated with time- and dose-dependent down regulation of the retinoblastoma protein Rb, diminution in the expression of anti-apoptotic proteins bcl-2 and survivin, increase in apoptogenic proteins bax and cytochrome c, and cleavage of poly(ADP-ribose) polymerase (PARP) from its native 112-kDa form to the 89-kDa truncated product. Moreover, I'm-Yunity™ (PSP)-treated HL-60 cells also showed a substantial decrease in p65 and to a lesser degree p50 forms of transcription factor NF-κB, which was accompanied by a reduction in the expression of cyclooxygenase 2 (COX2). I'm-Yunity™ (PSP) also elicited an increase in STAT1 (signal transducer and activator of transcription) and correspondingly, decrease in the expression of activated form of ERK (extracellular signal-regulated kinase).

Conclusion

Aqueous extracts of I'm-Yunity™ (PSP) induces cell cycle arrest and alterations in the expression of apoptogenic/anti-apoptotic and extracellular signaling regulatory proteins in human leukemia cells, the net result being suppression of proliferation and increase in apoptosis. These findings may contribute to the reported clinical and overall health effects of I'm-Yunity™ (PSP).

Inhibition of 7,12-Dimethylbenz(a)anthracene-Induced Skin Tumorigenesis in C57BL/6 Mice by Sulforaphane Is Mediated by Nuclear Factor E2–Related Factor 2

Sulforaphane, a dietary isothiocyanate, possesses potent chemopreventive effects through the induction of cellular detoxifying/antioxidant enzymes via the transcription factor nuclear factor E2-related factor 2 (Nrf2). To investigate carcinogenesis mechanisms related to the regulation of Nrf2, we examined the tumor incidence and tumor numbers per mouse in Nrf2 wild-type (+/+) and Nrf2 knockout (-/-) mice. 7,12-Dimethylbenz(a)anthracene/12-O-tetradecanoylphorbol-13-acetate treatments resulted in an increase in the incidence of skin tumors and tumor numbers per mouse in both genotypes; however, both indices were markedly higher in Nrf2(-/-) mice as compared with Nrf2(+/+) mice. Western blot analysis revealed that Nrf2 as well as heme oxygenase-1, a protein regulated by Nrf2 were not expressed in skin tumors from mice of either genotype, whereas expression of heme oxygenase-1 in Nrf2(+/+) mice was much higher than that in Nrf2(-/-) mice in nontumor skin samples. Next, we examined the chemopreventive efficacy of sulforaphane in mice with both genotypes. Topical application of 100 nmol of sulforaphane once a day for 14 days prior to 7,12-dimethylbenz(a)anthracene/12-O-tetradecanoylphorbol-13-acetate applications decreased the incidence of skin tumor in the Nrf2(+/+) mice when compared with the vehicle-treated group. Importantly, there was no chemoprotective effect elicited by sulforaphane pretreatment in the Nrf2(-/-) mice group. Taken together, our results show for the first time that Nrf2(-/-) mice are more susceptible to skin tumorigenesis and that the chemopreventive effects of sulforaphane are mediated, at least in part, through Nrf2.

Lunasin: a cancer-preventive soy peptide

Lunasin is a novel, cancer-preventive peptide whose efficacy against chemical carcinogens and oncogenes has been demonstrated in mammalian cells and in a skin cancer mouse model. Isolated and characterized in soy, lunasin peptide is also documented in barley. Lunasin is found in all of the genotypes analyzed from the US soy germ plasm collection and in commercially available soy proteins. Pilot studies show that lunasin is bioavailable in mice and rats when orally ingested, opening the way for dietary administration in cancer prevention studies. Lunasin internalizes into mammalian cells within minutes of exogenous application, and localizes in the nucleus after 18 hours. It inhibits acetylation of core histones in mammalian cells. In spite of its cancer-preventive properties, lunasin does not affect the growth rate of normal and established cancer cell lines. An epigenetic mechanism of action is proposed whereby lunasin selectively kills cells being transformed or newly transformed by binding to deacetylated core histones exposed by the transformation event, disrupting the dynamics of histone acetylation-deacetylation and leading to cell death.

Dietary agents in the chemoprevention of prostate cancer

Nutritional factors have been estimated to contribute 20-60% of cancers around the globe, and almost one-third of deaths are being reported in Western countries. According to estimates by the American Cancer Society, during the year 2005 about 232,090 new cases of prostate cancer will be diagnosed alone in the United States and 30,350 men will die of this disease. The high incidence and long latency period of prostate cancer offer plenty of time to pursue strategies toward prevention and/or treatment to suppress or revert this disease. Epidemiological evidence suggests that plant-based dietary agents decrease the risk of some types of human cancer, including prostate cancer. Intake of 400-600 g/day of fruits and vegetables is associated with reduced risk of several cancers. The use of micronutrients and/or other phenolic agents in the diet or synthetic exogenous supplements to prevent neoplastic transformation of normal cells or to slow the progression of established malignant changes in cancer cells is termed "chemoprevention." Considerable attention has been devoted to identify plant-based dietary agents that may serve as natural inhibitors of prostate carcinogenesis. Much progress has been made in the last decade in this area of investigation through identification of pathways that play important roles in prostate tumorigenesis. This article summarizes epidemiological, clinical, and mechanistic studies and the significance of plant-derived dietary agents such as flavonoids, indoles, isothiocyanates, phenolics, monoterpenes, and complementary and alternative agents in the management of prostate cancer with recommendations for future studies to advance this area of research.

Bioactive polyacetylenes in food plants of the Apiaceae family: Occurrence, bioactivity and analysis

Many bioactive compounds with known effects on human physiology and disease have been identified through studies of plants used in traditional medicine. Some of these substances occur also in common food plants, and hence could play a significant role in relation to human health. Food plants of the Apiaceae plant family such as carrots, celery and parsley, contain a group of bioactive aliphatic C17-polyacetylenes. These polyacetylenes have shown to be highly toxic towards fungi, bacteria, and mammalian cells, and to display neurotoxic, anti-inflammatory and anti-platelet-aggregatory effects and to be responsible for allergic skin reactions. The effect of these polyacetylenes towards human cancer cells, their human bioavailability and their ability to reduce tumour formation in a mammalian in vivo model indicates that they may also provide benefits for health. The present state of knowledge on the occurrence of polyacetylenes in Apiaceae food plants, their biochemistry and bioactivity is presented in this review as well as relatively new methods for the isolation and quantification of these compounds from plants, plant products and biological fluids.

Role of dietary factors in the development of basal cell cancer and squamous cell cancer of the skin

The role of dietary factors in the development of skin cancer has been investigated for many years; however, the results of epidemiologic studies have not been systematically reviewed. This article reviews human studies of basal cell cancer (BCC) and squamous cell cancer (SCC) and includes all studies identified in the published scientific literature investigating dietary exposure to fats, retinol, carotenoids, vitamin E, vitamin C, and selenium. A total of 26 studies were critically reviewed according to study design and quality of the epidemiologic evidence. Overall, the evidence suggests a positive relationship between fat intake and BCC and SCC, an inconsistent association for retinol, and little relation between beta-carotene and BCC or SCC development. There is insufficient evidence on which to make a judgment about an association of other carotenoids with skin cancer. The evidence for associations between vitamin E, vitamin C, and selenium and both BCC and SCC is weak. Many of the existing studies contain limitations, however, and further well-designed and implemented studies are required to clarify the role of diet in skin cancer. Additionally, the role of other dietary factors, such as flavonoids and other polyphenols, which have been implicated in skin cancer development in animal models, needs to be investigated.

The Protective Role of Fruits and Vegetables against Radiation-Induced Cancer

The role of fruits and vegetables in protecting against radiation-induced cancer and the positive evidence from epidemiology and ancillary investigations are discussed in this review. The recently reported Hiroshima and Nagasaki atomic bomb survivor studies provide strong evidence for the protective role of fruits and vegetables against radiation-induced cancer. The anticarcinogenic substances contained in, and the anticarcinogenic mechanisms proposed for, fruits and vegetables are reviewed. The anticarcinogenic effectiveness of fruits and vegetables are compared with that of dietary supplements. The reasons for the observed superiority of fruits and vegetables are advanced.

Inhibition of Akt signaling and enhanced ERK1/2 activity are involved in induction of macroautophagy by triterpenoid B-group soyasaponins in colon cancer cells

Triterpenoid B-group soyasaponins have been found to induce macroautophagy in human colon cancer cells at concentrations obtainable through consumption of legume foodstuffs. In the present studies the mechanism(s) for this autophagy-inducing action of soyasaponins was evaluated by measuring changes in signal transduction pathways associated with autophagy. Specifically, inhibition of the Akt signaling pathway and enhanced activity of ERK1/2 have previously been implicated in controlling induction of macroautophagy in mammalian cancer cells. Here we show that these pathways are also involved in B-group soyasaponin-induced macroautophagy, as changes in enzyme activities preceded significant increases in autophagic activity. The autophagic capacity of HCT-15 cells was significantly increased by 6 h post-saponin exposure, which led us to measure alterations in signaling events that preceded this time point. We determined that exposure to B-group soyasaponins suppressed Akt activity maximally by 50%, which was associated with a reduction in the activating phosphorylation of the Akt-serine473 residue. In addition, ERK1/2 activity was significantly increased by 60%, and was determined to be necessary for B-group soyasaponin-induced autophagy. The raf-1 kinase has been identified as a potential point of cross-talk between the Akt and ERK1/2 signaling cascades. Following B-group soyasaponin treatment activity of raf-1 was significantly increased by a maximal 200%, suggesting that this enzyme in part modulates the enhanced ERK1/2 activity. These results provide new insights into the signaling events that control induction of autophagy by B-group soyasaponins in human colon cancer cells and suggest that soyasaponins warrant further study as potential colon cancer chemopreventive agents.

Role of epoxide hydrolase, NAD(P)H:quinone oxidoreductase, cytochrome P450 2E1 or alcohol dehydrogenase genotypes in susceptibility to colorectal cancer

Colorectal cancer (CRC) is one of the most common forms of cancer in Western countries. CRC has been associated with genetic and lifestyle factors. Individual susceptibility to CRC may be due partly to variations in detoxification capacity in the gastrointestinal tract. Genetic polymorphisms in detoxification enzymes may result in variations in detoxification activities, which subsequently might influence the levels of toxic/carcinogenic compounds, and this may influence the risk for CRC. Therefore, we determined whether polymorphisms in the genes coding for microsomal epoxide hydrolase (EPHX1), NAD(P)H:quinone oxidoreductase (NQO1), cytochrome P450 2E1 (CYP2E1) and alcohol dehydrogenase (ADH3) predispose to the development of CRC. DNA samples were obtained from 371 patients with sporadic CRC and 415 healthy controls. Patients and controls were all of Caucasian origin. All genetic polymorphisms were determined by polymerase chain reaction, eventually followed by restriction-fragment-length-polymorphism analyses, except for the EPHX1 codon 113 polymorphism, which was genotyped by an allele-specific discrimination assay. Calculation of crude Odds Ratios (ORs) revealed an increased risk for CRC associated with variant NQO1 (OR 1.5, 95% CI 1.1-2.0) and CYP2E1 intron 6 genotypes (OR 2.2, 95% CI 1.3-3.8). However, after adjustment for age and gender, logistic regression analyses only showed a statistically significant risk for CRC associated with variant NQO1 genotypes (OR 1.6, 95% CI 1.03-2.4). No associations were found between CRC and the other polymorphic genes as mentioned above. In conclusion, these data suggest that the presence of variant NQO1 genotypes, with expected reduced enzyme activities might enhance susceptibility to CRC.

Induction of G2/M phase cell cycle arrest by carnosol and carnosic acid is associated with alteration of cyclin A and cyclin B1 levels

Carnosol and carnosic acid, two antioxidant polyphenols present in Rosmarinus officinalis (rosemary), were investigated for their antiproliferative properties toward Caco-2 cells. Twenty hours of treatment with both carnosol and carnosic acid inhibited 3H-thymidine incorporation in a dose-dependent manner, with a 50% inhibitory concentration of 23 microM and significantly increased the doubling time of Caco-2 cells from 29.5 to 140 and 120 h, respectively. These effects were associated with accumulation of treated cells in the G2/M phase of the cell cycle. Carnosol was found to exert its major cell cycle effect after prometaphase, and caused an increase in cyclin B1 protein levels whereas carnosic acid arrested cells prior to prometaphase, and caused a reduction in cyclin A levels. These structurally related phytochemicals, therefore, appear to arrest cells at different phases of the cell cycle possibly through influencing the levels of different cyclin proteins.

Inhibition of prostate cancer cell growth by an avocado extract: role of lipid-soluble bioactive substances

Although the avocado is known as a rich source of monounsaturated fatty acids, there has been far less attention given to its content of other bioactive substances including carotenoids, which might contribute to cancer preventive properties similar to those attributed to other fruits and vegetables. The yellow-green color of the avocado prompted us to study the carotenoid content of this fruit using established methods in our laboratory. The California Hass avocado (Persea americana Mill.) was selected for study, because it is the most commonly consumed variety in the southwest United States. These avocados were found to contain the highest content of lutein among commonly eaten fruits as well as measurable amounts of related carotenoids (zeaxanthin, alpha-carotene, and beta-carotene). Lutein accounted for 70% of the measured carotenoids, and the avocado also contained significant quantities of vitamin E. An acetone extract of avocado containing these carotenoids and tocopherols was shown to inhibit the growth of both androgen-dependent (LNCaP) and androgen-independent (PC-3) prostate cancer cell lines in vitro. Incubation of PC-3 cells with the avocado extract led to G(2)/M cell cycle arrest accompanied by an increase in p27 protein expression. Lutein alone did not reproduce the effects of the avocado extract on cancer cell proliferation. In common with other colorful fruits and vegetables, the avocado contains numerous bioactive carotenoids. Because the avocado also contains a significant amount of monounsaturated fat, these bioactive carotenoids are likely to be absorbed into the bloodstream, where in combination with other diet-derived phytochemicals they may contribute to the significant cancer risk reduction associated with a diet of fruits and vegetables.

Pathogenesis and risk factors of small bowel adenocarcinoma: a colorectal cancer sibling?

Small bowel adenocarcinoma (SBA) is a very rare entity accounting for one-fourth of the small intestine neoplasms. Usually accompanied by nonspecific symptoms occurring late in the course of the disease, they are associated with a dismal prognosis. It appears that SBA shares several genetic characteristics with large bowel tumors, but also has unique features. The purpose of this article is to review pathogenesis and risks factors of SBA to better understand its molecular features as well as its resemblances and dissimilarities with colorectal cancer (CRC). Better understanding of sporadic and hereditary genetic pathways potentially involved will undoubtedly lead to better prevention and therapeutic management of this rare but aggressive disease.

β-Sitosterol From Psyllium Seed Husk (Plantago ovata Forsk) Restores Gap Junctional Intercellular Communication in Ha-ras Transfected Rat Liver Cells

We purified compounds from the husks of psyllium seeds (Plantago ovata Forsk; desert Indian wheat), beginning with an ethanol extraction then followed by HP-20 and silica gel chromatography, which restored gap junctional intercellular communication (GJIC) in v-Ha-ras transfected rat liver epithelial WB-F344 cell line (WB-Ha-ras). GJIC was assessed by a scrape loading dye transfer assay. The active compound was identified as beta-sitosterol based on gas chromatography retention times and electron ionization mass spectroscopy (EI-MS) spectrum of authentic beta-sitosterol. Authentic beta-sitosterol restored GJIC in the tumorigenic WB-Ha-ras GJIC-deficient cells at a dose of 2.4 microM. In addition, a similar phytosterol, stigmasterol, also restored GJIC, albeit at a lower activity. beta-sitosterol and stigmasterol increased the level of connexin43 protein (Cx43) and restored phosphorylation of Cx43 to levels similar to the parental nontransfected cell line. We concluded that the restoration of intercellular communication in the GJIC-deficient, tumorigenic WB-Ha-ras cell line by the ethanol soluble fraction of psyllium seed husks is largely due to the presence of the phytosterol, beta-sitosterol. We discuss implications for dietary modulation of cancer by beta-sitosterol.

Expression of cellulose synthase-like (Csl) genes in insect cells reveals that CslA family members encode mannan synthases

Glucuronoarabinoxylan, xyloglucan, and galactomannan are noncellulosic polysaccharides found in plant cell walls. All consist of beta-linked glycan backbones substituted with sugar side chains. Although considerable progress has been made in characterizing the structure of these polysaccharides, little is known about the biosynthetic enzymes that produce them. Cellulose synthase-like (Csl) genes are hypothesized to encode Golgi-localized beta-glycan synthases that polymerize the backbones of noncellulosic polysaccharides. To investigate this hypothesis, we used heterologous expression in Drosophila Schneider 2 (S2) cells to systematically analyze the functions of the gene products of a group of Csl genes from Arabidopsis and rice (Oryza sativa L.), including members from five Csl gene families (CslA, CslC, CslD, CslE, and CslH). Our analyses indicate that several members of the CslA gene family encode beta-mannan synthases. Recombinant CslA proteins produce beta-linked mannan polymers when supplied GDP-mannose. The same proteins can produce beta-linked glucomannan heteropolymers when supplied both GDP-mannose and GDP-glucose. One CslA protein also produced beta-linked glucan polymers when supplied GDP-glucose alone. Heterologous expression studies of additional candidate glycan synthases in insect cells or other systems may help identify other noncellulosic polysaccharide biosynthetic enzymes.

Fat food habitual intake and risk of oral cancer

This case-control study evaluated fat food habitual intake in the context of the Brazilian diet as a risk factor for oral cancer. A food frequency questionnaire was applied to 70 patients with oral carcinoma and an equal number of controls treated in the same hospital for acute non-neoplastic conditions. Participants were paired for age, gender and smoking status, and matched by frequency for the use of dental prostheses and length of smoking history. Conditional logistic regression for multivariate analysis indicated as risk factors the habitual intake of foods rich in animal and saturated fat: pork meat, soup, cheese, bacon and fried food. The multivariate model also indicated the protective effect of non-cooked butter or margarine, probably the most effective vehicle for vitamin A ingestion in the Brazilian diet. These findings suggest that there is a non-negligible scope for the prevention of oral cancer through the improvement of diet.

Intestinal immunity of rats with colon cancer is modulated by oligofructose-enriched inulin combined with Lactobacillus rhamnosus and Bifidobacterium lactis

Probiotics (PRO) are known to modulate immunity in animals and human subjects and to inhibit colon carcinogenesis in experimental models, but the effects of synbiotics (SYN) are not well understood. Therefore, the effects of PRO (Lactobacillus rhamnosus GG and Bifidobacterium lactis Bb12), PRE (inulin-based enriched with oligofructose, 100 g/kg) and SYN (combination of PRO and PRE) on the immune system of rats were investigated in the azoxymethane (AOM)-induced colon cancer model. After 33 weeks, rats with and without AOM treatment were killed and immune cells were isolated from spleen, mesenterial lymph nodes (MLN) and Peyer's patches (PP). AOM treatment significantly reduced natural killer (NK) cell-like cytotoxicity in control rats and in PRO- and PRE-supplemented rats. SYN supplementation prevented the AOM-induced suppression of NK cell-like cytotoxicity in PP compared with control rats (P<0.01). SYN and PRE supplementation stimulated IL-10 production in PP in these rats (P<0.01) and in MLN of rats not treated with AOM (P<0.05). Interferon-gamma production in PP was decreased by PRO supplementation (PRO and SYN groups combined; P<0.05). Proliferative responsiveness of lymphocytes (PP) from AOM-treated rats was suppressed in SYN-supplemented rats (P<0.01). Overall, SYN supplementation in carcinogen-treated rats primarily modulated immune functions in the PP, coinciding with a reduced number of colon tumours. PRE and PRO provided in combination as SYN may contribute to the suppression of colon carcinogenesis by modulating the gut-associated lymphoid tissue.

Vitamin A prevents high fat diet-induced ACF development and modifies the pattern of expression of peroxisome proliferator and retinoic acid receptor m-RNA

Some dietary compounds, among them fats, are modulators of colon cancer risk. This study reports the modulating effects of n-6, with or without vitamin A, on promotion of colon preneoplasic lesions induced by 1,2-dimethylhydrazine (DMH) and on the expression of nuclear receptors (PPARgamma, RXRalpha, and RARbeta). One group of male Fisher rats was fed a basic diet (5% safflower oil) and two groups were fed a high-fat diet (HFD, 25% safflower oil). Of these, one was supplemented with 200 IU vitamin A for 5 mo. The safflower oil contained polyunsaturated fatty acids, mainly linoleic acid (73%). The data showed an increasing effect of safflower oil-enriched diet on aberrant crypt foci occurrence and multiplicity. This effect was impaired by vitamin A supplementation. In addition, an HFD-related up-regulation of PPARgamma and a concomitant down-regulation of RARbeta mRNA expression were observed with or without chemical initiation and were prevented by vitamin A. Moreover, when treated with DMH, HFD rats exhibited a dramatically decreased expression of RXRalpha mRNA (-49%). It was hypothesized that HFD, leading to hyperexpression of PPARgamma, would produce an alteration of retinoic acid signaling and, in this way, create a background modulating colon cancer risk.

Effect of Black Tea Intake on the Excretion of Mutagens in the Urine of Volunteers Taking a Beef Meal

The objective of this study was to investigate in a crossover study conducted in human volunteers whether black tea intake modulates the metabolism of heterocyclic amines, consumed in the form of well-cooked beefburgers, as exemplified by the excretion of mutagens in the urine. Mutagens were extracted from urine with blue rayon, and mutagenic activity was determined in the Ames test, in the presence of an activation system derived from Aroclor 1254–induced rats, and employing the Salmonella typhimurium O-acetylase over-expressing YG1024 bacterial strain. Volunteers consumed three well-cooked beefburgers, whereas a concurrently cooked fourth burger was analyzed for mutagenic activity. Following intake of the burgers, an increase in urinary mutagenic activity was observed, and mutagenic activity was completely excreted within 24 hours. A good correlation was obtained between the intake and excretion of mutagenic activity. The volunteers consumed the same burger meal on two different occasions, once following intake of 10 cups of strong black tea, and the second following intake of a corresponding volume of water. Urine was collected by each volunteer for 24 hours after the meal, and compliance was ascertained utilizing the excretion of p-aminobenzoic acid. The mutagenic ratio, defined as the ratio of urinary mutagenicity over the intake of mutagenicity, was not altered by the black tea, being 0.142 and 0.135 during the water and tea intake, respectively. It is inferred that short-term intake of high levels of black tea, as part of an otherwise normal diet, does not modulate the human metabolism of heterocyclic amines.

Dieta e câncer: um enfoque epidemiológico

Epidemiologistas que estudam câncer têm observado que a sua prevalência no mundo tem aumentado de maneira significativa no último século. Acredita-se que este resultado está relacionado, entre outros aspectos, com a industrialização e a urbanização ocorridas neste período. De fato, a morbi-mortalidade associada ao câncer observada em países desenvolvidos é maior do que em países em desenvolvimento. Além disso, algumas formas específicas de câncer, como o de cólon e reto, próstata e mama feminina, são mais freqüentes em países desenvolvidos, enquanto outras, como de estômago, esôfago e colo de útero têm maior incidência nos países em desenvolvimento. Padrões distintos de câncer também são observados entre indivíduos que emigram para um novo país ou região. Com base em estudos epidemiológicos, analisou-se a relação entre câncer e nutrição, e algumas modificações na alimentação que podem prevenir alguns tipos de cânceres.

Chemoprevention by isothiocyanates and their underlying molecular signaling mechanisms

Chemoprevention is a cancer preventive strategy to inhibit, delay or reverse carcinogenesis using naturally occurring or synthetic chemical agents. Numerous epidemiological studies as well as experimental animal studies clearly demonstrate that high intake of cruciferous vegetables protects against tumorigenesis. Thus, cruciferous vegetables have been of great interest for potential use in the chemoprevention of cancer. Cruciferous vegetables are rich source of glucosinolates, which are degraded into isothiocyanates by enzymatic action of plant-specific myrosinase or intestinal flora in the body. It appears that significant portion of the chemopreventive effects of isothiocyanates may be associated with the inhibition of the metabolic activation of carcinogens by cytochrome P450s (Phase I), coupled with strong induction of Phase II detoxifying and cellular defensive enzymes. Inductions of Phase II cellular enzymes are largely mediated by the antioxidant responsive element (ARE), which is regulated by the transcriptional factor, Nrf2. Additional potent regulatory mechanisms of Nrf2 include the different signaling kinase pathways (MAPK, PI3K, PKC and PERK) as well as other non-kinase dependent mechanisms. Moreover, apoptosis and cell cycle perturbations appear to be yet another potential chemopreventive mechanisms elicited by isothiocyanates, especially with respect to the effects on pre-initiated or initiated tumor cells. Finally, modulation of other critical signaling mediators, including the NF-kappaB and AP-1 by a wide array of chemopreventive agents including isothiocyanates may also contribute to the overall chemopreventive mechanisms.

Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Oxidative stress can cause cancer. Our aim was to establish whether antioxidant supplements reduce the incidence of gastrointestinal cancer and mortality.

METHODS

With the Cochrane Collaboration methodology, we reviewed all randomised trials comparing antioxidant supplements with placebo for prevention of gastrointestinal cancers. We searched electronic databases and reference lists (February, 2003). Outcome measures were incidence of gastrointestinal cancers, overall mortality, and adverse effects. Outcomes were analysed with fixed-effect and random-effects model meta-analyses and were reported as relative risk with 95% CIs.

FINDINGS

We identified 14 randomised trials (n=170,525). Trial quality was generally high. Heterogeneity of results was low to moderate. Neither the fixed-effect (relative risk 0.96, 95% CI 0.88-1.04) nor random-effects meta-analyses (0.90, 0.77-1.05) showed significant effects of supplementation with beta-carotene, vitamins A, C, E, and selenium (alone or in combination) versus placebo on oesophageal, gastric, colorectal, pancreatic, and liver cancer incidences. In seven high-quality trials (n=131727), the fixed-effect model showed that antioxidant significantly increased mortality (1.06, 1.02-1.10), unlike the random-effects meta-analysis (1.06, 0.98-1.15). Low-quality trials showed no significant effect of antioxidant supplementation on mortality. The difference between the mortality estimates in high-quality and low-quality trials was significant (Z=2.10, p=0.04 by test of interaction). beta-carotene and vitamin A (1.29, 1.14-1.45) and beta-carotene and vitamin E (1.10, 1.01-1.20) significantly increased mortality, whereas beta-carotene alone only tended to increase mortality (1.05, 0.99-1.11). In four trials (three with unclear or inadequate methodology), selenium showed significant beneficial effect on the incidence of gastrointestinal cancer.

INTERPRETATION

We could not find evidence that antioxidant supplements can prevent gastrointestinal cancers; on the contrary, they seem to increase overall mortality. The potential preventive effect of selenium should be studied in adequate randomised trials.

Arachidonic acid and colorectal carcinogenesis

Colorectal carcinoma is a leading cause of cancer related death worldwide. This deadly disease advances through a series of clinical and histopathological stages, initiated by single crypt lesions to small benign tumors and finally to malignancy. Although some progress has been made in elucidating the formation of colorectal tumors at molecular/genetic levels, the possible mechanisms of dietary lipids in inducing and promoting colorectal tumorigenesis are poorly understood. Recent epidemiological studies, however, indicate that lipid-rich diet containing omega-6 fatty acids (i.e. linoleic acid, arachidonic acid, etc.) may somehow be related with the disease process. Rapid metabolism of arachidonic acid, increased activities of phospholipases (i.e. phospholipase-A2s), and the elevated levels of cyclooxygenase (COX) and lipoxygenase (LOX) in colonic cells were reported in various stages of the malignancy, suggesting a possible link between dietary lipids and the incidence of colorectal cancer. The major focus of this review is to delineate the recent findings on enhanced arachidonic acid metabolism and its conversion into eicosanoids during the initiation and progression of colorectal carcinogenesis. In addition, the identification and participation of various phospholipases are also discussed. It is speculated that many of these phospholipases can be used as targets for developing new drugs against colorectal as well as other adenocarcinomas.

Arachidonic acid and colorectal carcinogenesis

Colorectal carcinoma is a leading cause of cancer related death worldwide. This deadly disease advances through a series of clinical and histopathological stages, initiated by single crypt lesions to small benign tumors and finally to malignancy. Although some progress has been made in elucidating the formation of colorectal tumors at molecular/genetic levels, the possible mechanisms of dietary lipids in inducing and promoting colorectal tumorigenesis are poorly understood. Recent epidemiological studies, however, indicate that lipid-rich diet containing omega-6 fatty acids (i.e. linoleic acid, arachidonic acid, etc.) may somehow be related with the disease process. Rapid metabolism of arachidonic acid, increased activities of phospholipases (i.e. phospholipase-A2s), and the elevated levels of cyclooxygenase (COX) and lipoxygenase (LOX) in colonic cells were reported in various stages of the malignancy, suggesting a possible link between dietary lipids and the incidence of colorectal cancer. The major focus of this review is to delineate the recent findings on enhanced arachidonic acid metabolism and its conversion into eicosanoids during the initiation and progression of colorectal carcinogenesis. In addition, the identification and participation of various phospholipases are also discussed. It is speculated that many of these phospholipases can be used as targets for developing new drugs against colorectal as well as other adenocarcinomas.

Effects of a low-fat vegan diet and a Step II diet on macro- and micronutrient intakes in overweight postmenopausal women

OBJECTIVE

This study investigated the nutrient intake of overweight postmenopausal women assigned to a low-fat vegan diet or a Step II diet.

METHODS

Fifty-nine overweight (body mass index, 26 to 44 kg/m2) postmenopausal women were randomly assigned to a self-selected low-fat vegan or a National Cholesterol Education Program Step II diet in a 14-wk controlled trial on weight loss and metabolism. Nutrient intake, which was measured per 1000 kcal, was the main outcome measure. Statistical analyses included within-group and between-group t tests examining changes associated with each diet.

RESULTS

Consumption of a low-fat vegan diet was associated with greater decreases in fat, saturated fat, protein, and cholesterol intakes and greater increases in carbohydrate, fiber, beta-carotene, and total vitamin A intakes than was a Step II diet. The low-fat vegan group also increased thiamin, vitamin B6, and magnesium intakes more than the Step II group, and both groups increased folic acid, vitamin C, and potassium intakes. If considering only food sources of micronutrients, the low-fat vegan group decreased vitamin D, vitamin B12, calcium, selenium, phosphorous, and zinc intakes compared with baseline. However, with incidental supplements included, decreases were evident only in phosphorous and selenium intakes. No micronutrient decreases were found in the Step II group.

CONCLUSIONS

Individuals on a low-fat vegan or Step II diet should take steps to meet the recommended intakes of vitamin D, vitamin K, folic acid, calcium, magnesium, and zinc. Individuals on a low-fat vegan diet should also ensure adequate intakes of vitamin B12, phosphorous, and selenium.

Effects of moderate exercise and oat β-glucan on lung tumor metastases and macrophage antitumor cytotoxicity

Both moderate exercise and the soluble fiber β-glucan can have beneficial effects on the initiation and growth of tumors, but the data are limited, and there is no information on their combined effects. This study tested the independent and combined effects of short-term moderate-exercise training and the soluble oat fiber β-glucan (OβG) on the metatastic spread of injected tumor cells and macrophage antitumor cytotoxicity. Male C57BL/6 mice were assigned to one of four groups: exercise (Ex)-H2O, Ex-OβG, control (Con)-H2O, or Con-OβG. OβG was fed in the drinking water for 10 days before tumor administration and death. Exercise consisted of treadmill running (1 h/day) for 6 days. After rest or exercise on the last day of training, syngeneic B16 melanoma cells (2 × 105) were administered via intravenous injection ( n = 8–11 per group). Lungs were removed 14 days later, and tumor foci were counted. Additional mice ( n = 8 per group) were killed, and peritoneal macrophages were assayed for cytotoxicity against the same mouse tumor cell line at various effector-to-target ratios. Both moderate exercise and OβG decreased lung tumor foci and increased macrophage cytotoxicity. However, there were no differences in lung tumor foci and macrophage cytotoxicity between Ex-OβG and either Ex-H2O or Con-OβG. These data suggest that, although not additive in their effects, both short-term moderate-exercise training and consumption of the soluble OβG can decrease the metatastic spread of injected B16 melanoma cells, and these effects may be mediated in part by an increase in macrophage cytotoxicity to B16 melanoma.

Position of the American Dietetic Association and Dietitians of Canada: Nutrition and Women’s Health

It is the position of the American Dietetic Association (ADA) and Dietitians of Canada (DC) that women have specific nutritional needs and vulnerabilities and, as such, are at unique risk for various nutrition-related diseases and conditions. Therefore, the ADA and the DC strongly support research, health promotion activities, health services, and advocacy efforts that will enable women to adopt desirable nutrition practices for optimal health. Women are at risk for numerous chronic diseases and conditions that affect the duration and quality of their lives. Although women's health-related issues are multifaceted, nutrition has been shown to influence significantly the risk of chronic disease and to assist in maintaining optimal health status. Dietetics professionals strongly support research, health promotion activities, health services, and advocacy efforts that will enable women to adopt desirable nutrition practices for optimal health.

Antitumor activity of extract of Zingiber aromaticum and its bioactive sesquiterpenoid zerumbone

The anticancer properties of zerumbone (2,6,9 humulatriene-8-one, a sesquiterpenoid) from Zingiber aromaticum were compared with those of curcumin from Curcuma longa in an in vitro MTT tetrazolium salt assay using HT-29, CaCo-2, and MCF-7 cancer cells and in an azoxymethane (AOM)-induced animal model of colon cancer using aberrant crypt foci (ACFs) as a preneoplastic marker. The IC50 of zerumbone was approximately 10 mM and that of curcumin was 25 mM. Cell cycle arrest in HT-29 cells was observed at G0/G1 for 10 and 12.5 mM and G2/M for 25 mM after 24 h at concentrations of 10-25 mM of zerumbone, and a concentration-dependent increase in apoptosis (2-6% of viable cells) was observed after 48 h using the same concentration range. Male Sprague-Dawley rats were fed extracts in an AIN diet prepared from the equivalent of 4% by weight of dried rhizomes of Z. aromaticum and C. longa. ACFs were induced by two doses (15 mg/kg body weight) subcutaneously of AOM 1 wk apart, the rats were killed 10 wk later, and the ACFs were assessed in the colon. Total ACFs were significantly reduced by Z. aromaticum extract (down 21%, P < 0.05) relative to control, the effect being most evident with large ACFs (>3 aberrant crypts per focus). Similar reductions were observed with 4% C. longa extract in the diet (down 24%, P < 0.01) and with 2,000 ppm curcumin, the effect being particularly evident with large ACFs. The concentration of zerumbone in the Z. aromaticum extract diet was assayed at 300 ppm and of curcumin in the C. longa extract diet was also 300 ppm, i.e., the extract of C. longa was as effective at one-seventh the concentration of curcumin as the positive control. Zerumbone is effective as an anticancer agent, possibly by its apoptosis-inducing and antiproliferative influences. This latter possibility is currently being investigated.

Psyllium extracts decreased neoplastic phenotypes induced by the Ha-Ras oncogene transfected into a rat liver oval cell line

Inhibition of gap junctional intercellular communication (GJIC) by tumor promoters and oncogenes has been implicated in the removal of initiated cells from the suppression of growth by neighboring cells in the tumor promoting step of carcinogenesis. The GJIC of WB-Ha-ras cell line is GJIC-deficient and they are capable of anchorage independent growth (AIG). The ethanol extract of psyllium increased GJIC 1.65-times and decreased AIG in both number and size of colonies in WB-Ha-ras cells. Histochemical staining of the gap junction protein, connexin43, showed that psyllium restored gap junction plaques on the plasma membrane of the WB-Ha-ras cells. In conclusion, the ethanol extract of psyllium reversed two tumor cell phenotypes, namely reduced GJIC and AIG, induced by the Ha-ras oncogene.

A cross-national comparison of lifestyle between China and the United States, using a comprehensive cross-national measurement tool of the healthfulness of lifestyles: the Lifestyle Index

BACKGROUND

Extensive studies have revealed the importance of a healthy lifestyle and the role of each lifestyle factor in health. However, lifestyle factors have rarely been studied simultaneously. The authors propose an integrated approach to summarize total healthfulness of lifestyles and to enhance understanding of lifestyle patterns across countries.

METHODS

The authors created an overall measure of lifestyle called the Lifestyle Index (LI), integrating diet, physical activity, smoking, and alcohol use to provide a global tool of monitoring healthfulness and patterns of lifestyles. Using the LI, the authors conducted a cross-national comparison between China (n = 8352) and the United States (n = 9750).

RESULTS

The LI effectively reflected the healthfulness of lifestyle components in both countries. The mean of the LI scores was slightly higher in China than the US. Scores of diet quality, physical activity, and smoking were higher in China, but scores of alcohol behavior were higher in the US. Similar lifestyle patterns but different unhealthy behaviors were identified in these countries.

CONCLUSIONS

An assessment of total healthfulness of lifestyles and a better understanding of lifestyle patterns across countries using the LI can provide practical guidance to developing and targeting public health promotion activities to improve global public health.

Beer and health: preventive effects of beer components on lifestyle-related diseases

It has been demonstrated that the light-to-moderate consumption of alcoholic beverages is associated with significant reductions in all-cause and particularly cardiovascular mortality. While the inverse association between red-wine consumption and cardiovascular risk is globally recognized as the French paradox, many epidemiological studies have concluded that beer and red wine are equally beneficial. Moderate alcohol intake improves lipoprotein metabolism and lowers cardiovascular mortality risk. The question now is whether additional health benefits associated with the non-alcohol components in beer may be expected. This article summarizes the results of the latest studies on the health benefits of beer while referring to our recent results, which demonstrate the preventive effects of beer and its components on lifestyle-related diseases. A series of studies using animal models have shown that beer may prevent carcinogenesis and osteoporosis; beer provides plasma with significant protection from oxidative stress; and isohumulones, the bitter substances derived from hops, may prevent and improve obesity and type-2 diabetes, improve lipid metabolism, and suppress atherosclerosis. Further studies are needed to clarify the components in addition to isohumulones that are responsible for these beneficial effects of beer, and the underlying mechanisms must be addressed.

Characterization of lunasin isolated from soybean

Lunasin is a novel and promising chemopreventive peptide from soybean. We have shown previously that lunasin suppresses transformation of mammalian cells caused by chemical carcinogens and inhibits skin carcinogenesis in mice when applied topically. Although the lunasin gene was cloned from soybean, all experiments carried out so far in our lab have used synthetic lunasin and therefore there is no detailed description of natural lunasin isolated from soybean. We report here the first characterization of soybean lunasin that includes definitive identification by mass peptide mapping, partial purification, and measurement of bioactivities of the various purified fractions and protein expression in the developing seed. The identity of lunasin in the seed extracts was established by Western blot analysis and mass spectrometric peptide mapping. All lunasin fractions partially purified by anion exchange and immunoaffinity column chromatography suppress colony formation induced by the ras-oncogene and inhibit core H3-histone acetylation. During seed development, lunasin peptide appears 5 weeks after flowering and persists in the mature seed. Western blot analysis of different soybean varieties and commercially available soy proteins shows the presence of the peptide in varying amounts. These results demonstrate the feasibility of producing large quantities of natural lunasin from soybean for animal and human studies.

Diet and oral, pharyngeal, and esophageal cancer

Cancers of the upper digestive tract, including those arising in the oral cavity, pharynx, and esophagus, present a significant public health problem worldwide. These cancers are associated with high morbidity and mortality, and identification of protective factors is very important. A number of epidemiological studies have examined the association between vegetables, fruits, carotene, vitamin A, vitamin C, and vitamin E and oral, pharyngeal, and esophageal cancers. The results of 35 epidemiological studies, including one prospective cohort study, one nested case-control study, two randomized controlled trials, nine population-based case-control studies, and 22 hospital-based case-control studies, in addition to in vitro and animal studies, were examined to determine whether the criteria for causal assumption were satisfied for a protective role of these dietary components against development of oral, pharyngeal, and esophageal cancers. There is enough evidence to point to a preventive role of vegetable intake, including green vegetables, cruciferous vegetables, and yellow vegetables, total fruit intake, and citrus fruit intake. Yellow fruits are likely to be protective. Carotene, vitamin C, and vitamin E are protective, most likely in combination with each other and other micronutrients. The role of vitamin A is not clear because of conflicting findings in the studies reviewed.

Diet, Nutrition, and Cancer Prevention: The Postgenomic Era

The genomic era of human nutrition is upon us: the human genome and several plant genomes have been characterized, and genetically modified foods are now abundantly available in the marketplace. The link between diet and cancer is well established, and new genomic technologies have made possible the investigation of nutritional modulation of the carcinogenesis pathway with nutrients, micronutrients, and phytochemicals. Current study of nutrient-modulated carcinogenesis involves exploring the effect of nutrients on DNA damage and repair mechanisms; DNA methylation, which influences gene expression and cellular phenotypes; antioxidant rearranging and oxidative stress; target receptors and signal transduction pathways; cell cycle controls and check points; apoptosis; and antiangiogenic processes. With nutritional genomics, proteomics, and metabolomics, scientists are able to simultaneously elucidate the biological effects of dietary constituents on cell function and global gene expression. This generation of new knowledge on nutrient-gene interactions provides the justification for a research framework for diet and cancer prevention that is focused on identifying and developing new biomarkers as well as a novel and contemporary paradigm for dietary intervention.

Characterization of nonstarch polysaccharides content from different edible organs of some vegetables, determined by GC and HPLC: comparative study

Content and composition of dietary fiber as nonstarch polysaccharides (NSP) was determined in vegetables belonging to different types of edible organs, using GC and HPLC. Samples analyzed were subterranean organs (radish and leek), leaves (celery, swiss chard, and lettuce), stalks (celery, swiss chard, and asparagus), inflorescence (broccoli), and fruits (tomato, green pepper, and marrow). The results indicate that though the monomeric profile is similar in all these samples quantitative differences were found for neutral sugars and uronic acids among samples of the same type of vegetal organ. The NSP values determined using CG method were in good agreement with HPLC method (R(2) = 0.9005). However, arabinose, mannose, and galactose plus rhamnose are more influenced by the analytical method used than the rest of the monomers in nearly all the samples analyzed. Final values of NSP depend on the method used in celery stalks, broccoli, and green pepper.