Carotenoids cell signaling

Fruifs and vegetables also contain ofher bioactive substances such as polyphenols (including well-known pigments anthocyanins, flavonols) and non-provitamin A carotenoids (mainly lycopene, lutein, and zeaxanthin) that may have protective effects on chronic diseases. Polyphenols and carotenoids are known to display antioxidant activities, counteracting oxidative alterations in cells. Besides these antioxidant properties, these colored bioactive substances may exert other actions on cell signaling and gene expression. 

This review reports the more recent evidence for the ability of P-carotene and other carotenoids to modulate cell signaling related to cell growth and implicated in a lot of pathological events, including cancer, inflammation, and atherosclerosis by both redox and non-redox mechanisms. 

Although further studies are needed to clarify the mechanism(s) of lycopene interference with cell signaling leading to down-regulation of cyclin Dl and ultimately to cell cycle arrest in both normal and tumor cells, these reports suggest that the reduction in cyclin Dl by lycopene treatment may be a key event in the ability of the carotenoid to arrest cell cycle progression. 

Bertram, J.S., 2008. Modulation of Gene Expression by Dietary Carotenoids and Retinoids Role in Cancer Prevention. In Dong, Z. Surh, Y. J. (Eds ). Dietary Modulation of Cell Signaling Pathways. CRC Press, 315-336. 

Data about curcunfin encapsulated in liposomes have been reported recently. The authors encapsulated curcumin into a liposomal delivery system in order to study the in vitro and in vivo effects of this compound on proliferation, apoptosis, signaling, and angiogenesis using human pancreatic carcinoma cells. Carotenoids of different polarities and in competition with cholesterol were specifically incorporated into liposomes in order to mimic the physiological uptake by cells and monitor their antioxidant capacities. ... 

At the moment, the role of p53 and its related genes in the regulation of cell growth signaling by carotenoids is not well understood and the results appear controversial. It is possible that several factors may influence the modulatory effects of P-carotene and other carotenoids on p53 levels, including the concomitant presence of smoke, the type and the concentration of the carotenoid, the association with other antioxidants as well as the biological cellular environment. 

Palozza, R, Serini, S., Di Nicuolo, R, and Calviello, G. 2004b. Modulation of apoptotic signalling by carotenoids in cancer cells. Arch Biochem Biophys 430 104-109. 

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