Osteoblasts lycopene effect

SaOS-2 osteoblasts (Kim et al., 2003). Such an effect was shown to be dependent on the stage of cell differentiation. The mechanism of the differentiating activity of lycopene is still unclear. One of the most reliable hypothesis is that the carotenoid may activate the expression of nuclear hormone receptors, such as RAR and RXR (Sharoni et al., 2002). 

Kim, L., Rao, A.V., and Rao, L.G. 2003. Lycopene II-effect on osteoblasts The carotenoid lycopene stimulates cell proliferation and alkaline phosphatase activity of SaOS-2 cells. J Med Food 6 79-86. 

They also reported that lycopene had a stimulatory effect on ALP activity, a marker of osteoblastic differentiation in more mature cells, but depending on the time of addition, it had an inhibitory or no effect on younger SaOS-Dex cells (Figure 14). These findings constituted the first report on the effect of lycopene on human osteoblasts. In another study by Park et al. (1997), the effect of lycopene on MC3T3 cells (the osteoblastic cells of mice) was contrary to the findings of Kim et al. (2003). Park demonstrated that lycopene had an inhibitory effect on cell proliferation. Both studies, however, reported that ALP activity was stimulated. The discrepancy in the effect of lycopene on cell proliferation could be a result of species differences or experimental conditions. More studies are required to clarify the role of lycopene in osteoblasts. 

FIG. 13 Effect of lycopene on the proliferation of SaOS-2 cells. Compared with respective vehicle control of the same dilution a = p < 0.05, b = p < 0.001, c=p < 0.005 (Kim et al., 2003). (Lycopene II - Effect on osteoblasts The carotenoid lycopene stimulates cell proliferations and alkaline phosphotase activity of SaOS-2 cells. Reprinted from Journal of Medicinal Food. 2003 6, pp. 79-86 by permission of Mary Ann Liebert, Inc., Publishers.)... 

The effects of lycopene on osteoclast formation and bone resorption were also reported by Ishimi et al. (1999) in murine osteoclasts formed in coculture with calvarial osteoblasts (Ishimi et al., 1999). Their results differed from those of Rao et al. (2003) in that they found that lycopene inhibited the PTH-induced, but not the basal, TRAP+ multinucleated cell formation. Furthermore, they could not demonstrate any effect of lycopene on bone resorption. They also did not study the effect of lycopene on ROS production. 

Human osteoblasts like cells osteosarcoma SaOS-2 cells were cultured for 24 hours, after which varying doses of a water dispersible microemulsion preparation of lycopene or vehicle of the same dilution were added. The cells were further cultured for 24 to 144 h and the cell numbers were counted. Lycopene at 10 and 10 M had significant stimulatory effects on cell numbers, compared with the corresponding vehicle treatment, at all time points from 24 h to 144 h. The effects of lycopene on activity of the differentiation marker alkaline phosphatase activity in the absence or presence of dexamethasone were shown to be dependent on osteoblasts of human origin [79]. 

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