Induction of Apoptosis by Hydroxydibenzoylmethane through Coordinative Modulation of Cyclin D3, Bcl-XL, and Bax, Release of Cytochrome c, and Sequential Activation of Caspases in Human Colorectal Carcinoma Cells
2003
Pan, Min-Hsiung | Huang, Meizhen | Wang, Ying-Jan | Lin, Jen-Kun | Lin, Chao-Hsien
DBM (dibenzoylmethane) is a minor constituent of licorice that has antimutagenic activity. However, its other biological activities are not well-known. The structurally related β-diketones hydroxydibenzoylmethane (HDB) and hydroxymethyldibenzoylmethane (HMDB) were able to induce apoptosis in colorectal carcinoma COLO 205 cells. Thus, the effect of structurally related β-diketones on cell viability, DNA fragmentation, and caspase activity was assessed. The potency of these compounds on these features of apoptosis were in the order of HDB > HMDB > DBM in colorectal carcinoma COLO 205 cells. Here, we found that HDB-induced apoptotic cell death was accompanied by upregulation of cyclin D3, Bax, and p21 and down-regulation of Bcl-XL, while HDB had no effect on the levels of Bcl-2 and Bad protein. These results indicate that HDB allows caspase-activated deoxyribonuclease to enter the nucleus and degrade chromosomal DNA and induces DFF-45 degradation. It is suggested that HDB-induced apoptosis is triggered by the release of cytochrome c into cytosol, procaspase-9 processing, activation of caspase-3 and caspase-2, degradation of PARP, and DNA fragmentation caused by the caspase-activated deoxyribonuclease through the digestion of DFF-45. The induction of apoptosis by HDB may provide a pivotal mechanism for its cancer chemopreventive action.
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