Induction of Bax and activation of caspases during β-sitosterol-mediated apoptosis in human colon cancer cells
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- Published online on: December 1, 2003 https://doi.org/10.3892/ijo.23.6.1657
- Pages: 1657-1662
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Abstract
β-sitosterol, a main dietary phytosterol found in plants, may have the potential for prevention and therapy for human cancer. The purpose of the present study was to examine the effect of β-sitosterol on the growth of HT116 human colon cancer cells. Treatment with β-sitosterol resulted in a dose-dependent growth inhibition coupled with the characteristic morphological features of apoptosis and with the increase of a sub-G1 cell population. Apoptosis-inducing concentrations of β-sitosterol induced caspase-3 and caspase-9 activation accompanied by proteolytic cleavage of poly(ADP-ribose)-polymerase. In addition, β-sitosterol-induced apoptosis in HT116 cells was associated with a decreased expression of the anti-apototic Bcl-2 protein and mRNA and a concomitant increase of the pro-apototic Bax protein and mRNA, and with release of cytochrome c from the mitochondria into the cytosol. β-sitosterol treatment also inhibited the expression of cIAP-1 without significant changes in the level of cIAP-2. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-cancer activity of β-sitosterol.