Anticancer activity of lycopene in HT-29 colon cancer cell line

An inverse association between serum lycopene levels and the risk of cancers has been pointed out by many prospective and retrospective epidemiological studies which prompted more studies to be performed on animal models and cell cultures in order to test this hypothesis. The aim of the present study was to evaluate the antiproliferative and pro-apoptotic effect of lycopene on colon cancer HT-29 cell line. The effect of lycopene on the viability of HT-29 cell line was investigated using XTT assay. The levels of Bcl-2, cleaved caspase 3, BAX, cleaved PARP, and 8-oxo-dG in lycopene-treated HT-29 cells were measured using ELISA. Gamma-H2AX and cytochrome c expression was assessed semi-quantitatively using immunofluorescence staining. Lycopene at doses of 10 and 20 mu M produced a significant antiproliferative effect on HT-29 cells compared to the control (p < 0.05). The IC50 value of lycopene in HT-29 cells was found to be 7.89 mu M for 24 h. Lycopene (7.89 mu M) significantly elevated cleaved caspase 3 (p < 0.01), BAX, and cleaved PARP, 8-oxo-dG levels (p < 0.05). The levels of gamma-H2AX foci are significantly higher while the levels of cytochrome-c are lower (p < 0.05) in lycopene-treated HT-29 cells. These results indicate that lycopene has an antiproliferative apoptotic and genotoxic effect on HT-29 colon cancer cell line.