Tumor-promoting phorbol esters, like growth factors, elicit pleiotropic responses involving biochemical pathways that lead to different biological responses. Genetic variant cell lines that are resistant to mitogenic, differentiation, or transformation responses to tumor promoters have been valuable tools for understanding the molecular bases of these responses.
Food and Chemical Toxicology: An International Journal Published for the British Industrial Biological Research Association
The French paradox is a dietary anomaly which has focused attention on the Mediterranean diet. Epidemiological studies revealed that this diet, replete in flavonoid-rich foods (Allium and Brassica vegetables, and red wine), correlated with the increased longevity and decreased incidence of cardiovascular disease seen in these populations. The most frequently studied flavonoid, quercetin, has been shown to have biological properties consistent with its sparing effect on the cardiovascular system.
Hardly an aspect of aging is more important than an organism's ability to withstand stress or to resist both internally and externally imposed insults. We know that as organisms loose their ability to resist these insults, aged organisms suffer more than the young. Therefore, a prime strategy for an organism's survival has been the evolutionarily adapted defense systems that guard against insult. For better survivability, an organism's defense system must be maximized to its full effect through well-coordinated networks of diverse biologically responsive elements.
Long-term dietary restriction (DR) robustly inhibits various types of carcinogenesis in rodents. Because malignancies are a major cause of death in humans, reducing the incidence or, at least, delaying the time of onset of neoplasia may significantly increase longevity of a large proportion of the human population. Long-term DR may not however be practical in humans and, judging from religious practices, several days of fasting to several weeks of DR is what a large segment of the human population can adhere to.
In this summary, J. Konietzko (Mainz) stressed the exceptional position of occupational cancer, which is due to the long latent period between exposure to specific carcinogens and cancer manifestation. Obviously, this long latent period of years to decades poses problems in the search for the etiology of occupational cancer. Three methodological areas are instrumental in overcoming these problems. They include epidemiological investigations, in vitro experiments and animal experiments, which have to complement each other.
Pinitol (3-O-methyl-chiroinositol), a component of traditional Ayurvedic medicine (talisapatra), has been shown to exhibit anti-inflammatory and antidiabetic activities through undefined mechanisms. Because the transcription factor nuclear factor-kappaB (NF-kappaB) has been linked with inflammatory diseases, including insulin resistance, we hypothesized that pinitol must mediate its effects through modulation of NF-kappaB activation pathway. We found that pinitol suppressed NF-kappaB activation induced by inflammatory stimuli and carcinogens. This suppression was not specific to cell type.
Berberine, an isoquinoline alkaloid derived from a plant used traditionally in Chinese and Ayurvedic medicine, has been reported to exhibit chemopreventive and anti-inflammatory activities through unknown mechanism. Because of the critical role of the transcription factor nuclear factor-kappaB (NF-kappaB) in these processes, we investigated the effect of berberine on this pathway. We found that berberine suppressed NF-kappaB activation induced by various inflammatory agents and carcinogens. This alkaloid also suppressed constitutive NF-kappaB activation found in certain tumor cells.