Search

Background Evidence from epidemiological and experimental studies has shown that the etiology of colorectal cancer (CRC) is related to lifestyle, mainly diet. At the same time, there are many foods and beverages that have been shown to provide protection against CRC. We turned our attention to a traditional Japanese food, brown algae, that contains carotenoids and various functional polyphenols, especially fucoxanthin (FX) and fucoxanthinol (FxOH). Results Both FX and FxOH treatments induced apoptosis in a dose-dependent and time-dependent manner as detected by annexin V / propidium iodide and the presence of a subG1 population in human colon cancer HCT116 cells. This apoptotic effect of FxOH was stronger than that of FX. We also found that nuclear factor-kappa B (NF-κB) transcriptional activity was significantly increased by treatment with ≥5 μM FxOH. Thus, we cotreated the cells with FxOH plus NF-κB inhibitor, and the results demonstrated that this cotreatment strongly enhanced the induction of apoptosis compared with the effects of FxOH or NF-κB inhibitor treatment alone and resulted in X-linked inhibitor of apoptosis (IAP) downregulation. Conclusions This study suggested that FxOH is a more potent apoptosis-inducing agent than FX and that its induction of apoptosis is enhanced by inhibiting NF-κB transcriptional activity via suppression of IAP family genes.

Evidence from epidemiological and experimental studies has shown that non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colorectal cancer (CRC). The function of NSAIDs and the molecular targets for chemopreventive effects on CRC have been extensively studied and their data were reported. However, the relation between NSAIDs and the risk factors of CRC have not been fully elucidated yet. Thus, relations between NSAIDs and the risk factors of CRC, such as overweight and obesity, alcohol, aging, hypertriglyceridemia and smoking, are summarized with our data and with recent reported data in this review.