Worldwide prevention of cancer and other chronic diseases based on knowledge of mechanisms

Therapeutic Potential of Brassinosteroids in Biomedical and Clinical Research

Steroids are a pivotal class of hormones with a key role in growth modulation and signal transduction in multicellular organisms. Synthetic steroids are widely used to cure large array of viral, fungal, bacterial, and cancerous infections. Brassinosteroids (BRs) are a natural collection of phytosterols, which have structural similarity with animal steroids. BRs are dispersed universally throughout the plant kingdom. These plant steroids are well known to modulate a plethora of physiological responses in plants leading to improvement in quality as well as yield of food crops. Moreover, they have been found to play imperative role in stress-fortification against various stresses in plants. Over a decade, BRs have conquered worldwide interest due to their diverse biological activities in animal systems. Recent studies have indicated anticancerous, antiangiogenic, antiviral, antigenotoxic, antifungal, and antibacterial bioactivities of BRs in the animal test systems. BRs inhibit replication of viruses and induce cytotoxic effects on cancerous cell lines. Keeping in view the biological activities of BRs, this review is an attempt to update the information about prospects of BRs in biomedical and clinical application.

Analysis of Plant Extracts Antimutagenicity Using the Ames Test and the Cytogenetic Analysis of Peripheral Blood Lymphocytes

This work was focused on comparison of antimutagenic effect of selected plant extracts (carrot, paprika, tomato, spinach, onion, kiwi and green tea) analysed by two independent tests of genotoxicity: i) the Ames test with Salmonella typhimurium TA98 and ii) cytogenetic analysis of peripheral blood lymphocytes (CAPL). Both methods were proved without and/or with metabolic activation. Samples were allowed to be positive antimutagens based on their ability to inhibit the mutagenic effects of standard mutagens. High positive results (more than 60% of inhibition of mutagenic effect) were obtained with extract from green tea. Extracts from paprika, carrot and spinach as well as solutions of standard alltrans-carotene and some standard flavonoids showed antimutagenic (40-60% of inhibition) or weakly antimutagenic (20-40% of inhibition) effects. Positive antimutagenic effects of extracts from spinach and green tea were determined using CAPL method too. Further, the comparison of antimutagenic activity and antioxidant capacity of tested samples analysed using TRAP (total radical-trapping antioxidant parameter) method was proved. Extract from green tea showed the highest antioxidant as well as antimutagenic capacity, but no correlation was found between these parameters in all tested extracts.

[A critical assessment of phytotherapy for prostate cancer]

Prostate cancer patients increasingly use complementary and alternative medicines to support the body's immune system in addition to conventional treatment to minimize morbidity associated with conventional treatment, to enhance the quality of life, and ultimately in the hope to cure cancer when conventional treatment fails. As there is a large variety of phytomedicines promoted as potential treatment for prostate cancer, the aim of this review was to differentiate between preventive and therapeutic approaches and evaluate which phytochemicals might be suited for therapy of prostate cancer. Therefore, preclinical in vitro and in vivo data as well as clinical trials with phytosubstances such as genistein, lycopene, epigallocatechin gallate, resveratrol, and mistletoe were assessed. The presented data show that at present there is no clinical evidence that phytochemicals might have a therapeutic use in prostate cancer in relation to reduction of tumor progression or improved survival. The question about an improved immune function or quality of life remains open. Potentially the use of phytochemicals could play a role in a preventive setting.

Anticancer and antiproliferative activity of natural brassinosteroids

Brassinosteroids (BRs) are steroid plant hormones that are essential for many plant growth and developmental processes, including cell expansion, vascular differentiation and stress responses. Up to now the inhibitory effects of BRs on cell division of mammalian cells are unknown. To determine basic anticancer structure-activity relationships of natural BRs on human cells, several normal and cancer cell lines have been used. Several of the tested BRs were found to have high cytotoxic activity. Therefore, in our next series of experiments, we tested the effects of the most promising and readily available BR analogues with interesting anticancer properties, 28-homocastasterone (1) and 24-epibrassinolide (2), on the viability, proliferation, and cycling of hormone-sensitive/insensitive (MCF-7/MDA-MB-468) breast and (LNCaP/DU-145) prostate cancer cell lines to determine whether the discovered cytotoxic activity of BRs could be, at least partially, related to brassinosteroid-nuclear receptor interactions. Both BRs inhibited cell growth in a dose-dependent manner in the cancer cell lines. Flow cytometry analysis showed that BR treatment arrested MCF-7, MDA-MB-468 and LNCaP cells in G(1) phase of the cell cycle and induced apoptosis in MDA-MB-468, LNCaP, and slightly in the DU-145 cells. Our results provide the first evidence that natural BRs can inhibit the growth, at micromolar concentrations, of several human cancer cell lines without affecting the growth of normal cells. Therefore, these plant hormones are promising leads for potential anticancer drugs.

LF, Lopes C. Chemical carcinogenesis

The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair - i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.

Behavior of glucosinolates in pickling cruciferous vegetables

Crucifer species, which include widely consumed vegetables, contain glucosinolates as secondary metabolites. Cruciferous vegetables are consumed in Japan in salt-preserved or pickled form as well as cooked and raw fresh vegetables. In this study, changes in contents of glucosinolates during the pickling process were investigated. 4-Methylthio-3-butenyl glucosinolate, a major glucosinolate in the root of Japanese radish, daikon (Raphanus sativus L.), was detected in pickled products with a short maturation period but not in those with a long maturation period. As a model pickling experiment, fresh watercress (Nasturtium officinale) and blanched watercress were soaked in 3% NaCl solution for 7 days. The results showed that the ratio of indole glucosinolates to total glucosinolates increased during the pickling process, whereas total glucosinolates decreased. Myrosinase digestion of glucosinolates in nozawana (Brassica rapa L.) indicated that indole glucosinolates, especially 4-methoxyglucobrassicin, were relatively resistant to the enzyme. The effect of pickling on glucosinolate content and the possible mechanism are discussed in view of degradation by myrosinase and synthetic reaction in response to salt stress or compression during the pickling process.

Suppressive effect of 1,4-phenylene diisothiocyanate on N-butyl-N-(4-hydroxybutyl)nitrosamine-induced urinary bladder carcinogenesis in male ICR mice

The modifying effects of dietary administration of 1,4-phenylene diisothiocyanate (DITC) on N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced urinary bladder carcinogenesis during the initiation and post-initiation phases were examined in male ICR mice. Five-week-old animals were divided into 5 groups. Groups 1-3 were given BBN (500 ppm) in drinking water for 6 weeks starting at age 6 week. Mice in Group 2 were given the diet containing 100 ppm DITC for 8 weeks during the initiation phase, starting 1 week before BBN exposure. Animals in Group 3 were fed the experimental diet for 24 weeks during the post-initiation phase starting 1 week after the cessation of BBN exposure. Mice in Group 4 were given only the diet containing the test compound, and those in Group 5 were given the basal diet alone throughout the experiment (32 weeks). The frequency of bladder lesions, neoplasms, dysplasia and hyperplasia, was analyzed histopathologically. The cell-proliferation activity estimated by the 5-bromodeoxyuridine labeling index (BrdU-LI), and cell cycle progression by counting cyclin D1-positive cell ratios were compared among the groups using immunohistochemistry. Administration of DITC in the initiation phase reduced significantly the incidence of urinary bladder carcinoma and dysplasia. The frequencies of any lesions of urinary bladder were not reduced by DITC in post-initiation phase. Dietary exposure of this agent in initiation phase reduced significantly both BrdU-LI and cyclin D1-positive cell ratios in any bladder lesions. Administration of DITC in post-initiation phase also significantly reduced BrdU-LI in bladder neoplasms and hyperplasia and cyclin D1-positive cell ratios in urinary bladder carcinoma as well as dysplasia. These results suggest that dietary DITC could be a preventive agent against BBN-induced bladder carcinogenesis in mice when fed during the initiation phase.

Effects of exercise and diet on chronic disease

Currently, modern chronic diseases, including cardiovascular diseases, Type 2 diabetes, metabolic syndrome, and cancer, are the leading killers in Westernized society and are increasing rampantly in developing nations. In fact, obesity, diabetes, and hypertension are now even commonplace in children. Clearly, however, there is a solution to this epidemic of metabolic disease that is inundating today's societies worldwide: exercise and diet. Overwhelming evidence from a variety of sources, including epidemiological, prospective cohort, and intervention studies, links most chronic diseases seen in the world today to physical inactivity and inappropriate diet consumption. The purpose of this review is to 1) discuss the effects of exercise and diet in the prevention of chronic disease, 2) highlight the effects of lifestyle modification for both mitigating disease progression and reversing existing disease, and 3) suggest potential mechanisms for beneficial effects.

Sanguinarine causes cell cycle blockade and apoptosis of human prostate carcinoma cells via modulation of cyclin kinase inhibitor-cyclin-cyclin-dependent kinase machinery

Prostate cancer is the second leading cause of cancer-related deaths in males in the United States. This warrants the development of novel mechanism-based strategies for the prevention and/or treatment of prostate cancer. Several studies have shown that plant-derived alkaloids possess remarkable anticancer effects. Sanguinarine, an alkaloid derived from the bloodroot plant Sanguinaria canadensis, has been shown to possess antimicrobial, anti-inflammatory, and antioxidant properties. Previously, we have shown that sanguinarine possesses strong antiproliferative and proapoptotic properties against human epidermoid carcinoma A431 cells and immortalized human HaCaT keratinocytes. Here, employing androgen-responsive human prostate carcinoma LNCaP cells and androgen-unresponsive human prostate carcinoma DU145 cells, we studied the antiproliferative properties of sanguinarine against prostate cancer. Sanguinarine (0.1–2 μmol/L) treatment of LNCaP and DU145 cells for 24 hours resulted in dose-dependent (1) inhibition of cell growth [as evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay], (2) arrest of cells in G0-G1 phase of the cell cycle (as assessed by DNA cell cycle analysis), and (3) induction of apoptosis (as evaluated by DNA ladder formation and flow cytometry). To define the mechanism of antiproliferative effects of sanguinarine against prostate cancer, we studied the effect of sanguinarine on critical molecular events known to regulate the cell cycle and the apoptotic machinery. Immunoblot analysis showed that sanguinarine treatment of both LNCaP and DU145 cells resulted in significant (1) induction of cyclin kinase inhibitors p21/WAF1 and p27/KIP1; (2) down-regulation of cyclin E, D1, and D2; and (3) down-regulation of cyclin-dependent kinase 2, 4, and 6. A highlight of this study was the fact that sanguinarine induced growth inhibitory and antiproliferative effects in human prostate carcinoma cells irrespective of their androgen status. To our knowledge, this is the first study showing the involvement of cyclin kinase inhibitor-cyclin-cyclin-dependent kinase machinery during cell cycle arrest and apoptosis of prostate cancer cells by sanguinarine. These results suggest that sanguinarine may be developed as an agent for the management of prostate cancer.

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.

Pharmacokinetic interactions between warfarin and kangen-karyu, a Chinese traditional herbal medicine, and their synergistic action

Kangen-Karyu (KGK), containing six herbs, is a formula created under the theory of Chinese traditional medicine (CTM) to invigorate the 'blood' and dispel 'blood stasis', which arises from poor blood circulation. The present study was conducted to evaluate the interactions between KGK and warfarin. Warfarin was administered orally or intravenously to KGK-treated rats, and plasma warfarin concentration and prothrombin time were measured. Although KGK did not influence the absorption or serum protein binding of warfarin, KGK significantly suppressed the metabolism and elimination of warfarin. This interaction depends on the dosage of KGK, and ten times the amount of the human daily dose of KGK did not exhibit pharmacokinetic interaction with warfarin, suggesting that KGK did not influence the effect of warfarin unless the daily dose was strictly maintained. Warfarin alone significantly prolonged mice tail-bleeding time, which was further prolonged significantly by KGK at a dose that did not exhibit pharmacokinetic interactions with warfarin, suggesting that KGK and warfarin might synergistically prevent thrombosis, and that combined use of these drugs could be therapeutically valuable. When physicians or pharmacists utilize combined therapy using warfarin and KGK, they must make a careful effort to check the coagulative status and regulate the dosage of each drug.

Catechins are not major components responsible for anti-genotoxic effects of tea extracts against nitroarenes

The anti-genotoxic properties of tea leaf extracts were examined in a Salmonella umu-test. Seven non-fermented teas (green tea), one semi-fermented tea (oolong tea), two fermented teas (black tea and Chinese pu er tea) and two other teas were examined for their anti-genotoxic abilities and for their catechins contents. This was to study the relationship between catechins contents and anti-genotoxic activity of various tea leaf extracts. All types of tea extracts showed more potent suppressive effects against umu gene expression of the SOS response in Salmonella typhimurium TA1535/pSK 1002 induced by four nitroarenes (1-nitropyrene, 2-nitrofluorene, 3-nitrofluoranthene and a mixture of 1,6- and 1,8-dinitropyrene) rather than 4-NQO, AF-2 and MNNG. The anti-genotoxic effect of 12 tea leaf extracts on 1-NP, 2-NF, 3-NF and DNP decreased in the order: oolong tea (semi-fermented tea)>black tea (fermented tea)>sencha (non-fermented tea, an ordinary grade green tea)>tocyucya (other tea)>Chinese pu er tea (fermented tea). The amount of catechins (EGC, C, EGCG, EC and ECG) in various teas in decreasing order was non-fermented tea>semi-fermented tea>fermented tea>other tea. A remarkable feature was the effectiveness of black tea and Chinese pu er tea in suppressing the genotoxicity induced by nitroarenes, in spite of the fact that these fermented teas do not have high catechins contents. Statistical analysis showed that no significant (P<0.01) correlation was found between the anti-genotoxicity of tea extracts against nitroarenes and the catechins contents in tea leaf extracts. In further experiment, fractionation of sencha extract by HPLC revealed that anti-genotoxicity of the peak fraction corresponding to catechins accounted for <10% of the total anti-genotoxic activity of sencha extract against for 1-nitropyrene. These results suggest that catechins are not major components responsible for the anti-genotoxic effects of tea leaf extracts against direct-acting nitroarenes.

A 7-item versus 31-item food frequency questionnaire for measuring fruit, juice, and vegetable intake among a predominantly African-American population

OBJECTIVE

This study sought to determine which of 2 fruit and vegetable food frequency questionnaires (FFQs) most closely approximated intake measured by the average of four 24-hour dietary recalls.

DESIGN

Participants completed either a 31-item FFQ (n = 70) or 7-item FFQ (n = 76) on 2 occasions approximately 2 weeks apart. During the interval between FFQs1 participants provided four 24-hour dietary recalls via telephone interview.

SUBJECTS/SETTING

Participants were 146 persons with food preparation responsibilities in families of students in grades 3 through 5. Respondents were predominantly African-American women in Atlanta, Ga.

STATISTICAL ANALYSIS

Pearson correlation coefficients of log-transformed values estimated the reliability of each FFQ and compared FFQ estimates to reference values. The intraclass correlation coefficient evaluated consistency across 24-hour recalls.

RESULTS

The first FFQs overestimated intake approximately twofold. The 31-item FFQ estimates exceeded 7-item FFQ estimates by approximately 30% . Correlations with recall estimates were high for the 7-item FFQ and moderate to low for the 31-item FFQ. The second FFQ estimates were more highly correlated to reference values. From the first to the second administration, 7-item FFQ estimates dropped from 5.2 to 2.7 servings, and 31-item FFQ estimates dropped from 6.7 to 3.5 servings. Neither FFQ produced highly reliable estimates.

CONCLUSIONS

Mean total fruit and vegetable consumption was closer to reference estimates for the first 7-item FFQ and the second 31-item FFQ. The 7-item FFQ correlated more highly with reference estimates than did the 31-item FFQ. Therefore, we conclude that for African-American adults, a 1-time-administered FFQ using 7 broad food categories correlates more highly with reference values than a FFQ using 31 individual fruit and vegetable items.

Growth inhibition, cell-cycle dysregulation, and induction of apoptosis by green tea constituent (-)-epigallocatechin-3-gallate in androgen-sensitive and androgen-insensitive human prostate carcinoma cells

Prostate cancer (PCA) is the most prevalent cancer diagnosed and the second leading cause of cancer-related deaths among men in the United States. Descriptive epidemiological data suggest that androgens and environmental exposures play a key role in prostatic carcinogenesis. Since androgen action is intimately associated with proliferation and differentiation, at the time of clinical diagnosis in humans most PCA represent themselves as a mixture of androgen-sensitive and androgen-insensitive cells. Androgen-sensitive cells undergo rapid apoptosis upon androgen withdrawal. On the other hand, the androgen-insensitive cells do not undergo apoptosis upon androgen blocking, but maintain the molecular machinery of apoptosis. Thus, agents capable of inhibiting growth and/or inducing apoptosis in both androgen-sensitive and androgen-insensitive cells will be useful for the management of PCA. In the present study, we show that (-)-epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent present in green tea, imparts antiproliferative effects against both androgen-sensitive and androgen-insensitive human PCA cells, and this effect is mediated by deregulation in cell cycle and induction of apoptosis. EGCG treatment was found to result in a dose-dependent inhibition of cell growth in both androgen-insensitive DU145 and androgen-sensitive LNCaP cells. In both the cell types, EGCG treatment also resulted in a dose-dependent G(0)/G(1)-phase arrest of the cell cycle as observed by DNA cell-cycle analysis. As evident by DNA ladder assay, confocal microscopy, and flow cytometry, the treatment of both DU145 and LNCaP cells with EGCG resulted in a dose-dependent apoptosis. Western blot analysis revealed that EGCG treatment resulted in (i) a dose-dependent increase of p53 in LNCaP cells (carrying wild-type p53), but not in DU145 cells (carrying mutant p53), and (ii) induction of cyclin kinase inhibitor WAF1/p21 in both cell types. These results suggest that EGCG negatively modulates PCA cell growth, by affecting mitogenesis as well as inducing apoptosis, in cell-type-specific manner which may be mediated by WAF1/p21-caused G(0)/G(1)-phase cell-cycle arrest, irrespective of the androgen association or p53 status of the cells.

Carcinogenicity and mutagenicity testing, then and now

Cancer is a dread disease worldwide. Mortality of individuals suffering from cancer is high, despite the current improved methods of precocious detection, surgery and therapy. Prevention of cancer is the recognized goal of many activities in cancer research. This aim was recognized early to involve the bioassay of environmental chemicals or mixtures. The first such study involved application of coal tar to the ear of rabbits, and later on to the skin of mice. Subsequently, laboratory rats were introduced, and hamsters were utilized as a substitute for the unwieldy tests in rabbits. Investigators also became concerned with the mechanisms of carcinogenesis, and more definitive approaches to carcinogen bioassay in laboratory animals, as possible indicators of cancer risk in humans. These tests were expensive and lengthy, and did not serve the important purpose of accurately measuring risk of cancer to humans. Once it was realized that DNA and the genetic apparatus might be a key target, rapid bioassays in bacterial and mammalian cell systems were introduced successfully. Thus, batteries of tests are now available to detect effectively human cancer risks, and provide novel approaches to determine the underlying mechanisms, as a sound basis for cancer prevention.