Induction of Apoptosis in Human Hepatoma SMMC-7721 Cells using 2′,4′-Dihydroxy-6′-methoxy-3′,5′-dimethylchalcone, a Chalcone from Buds of Cleistocalyx operculatus

The molecular mechanism to induce apoptosis in human hepatoma SMMC-7721 cells was investigated using 2',4'-Dihydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC) isolated from the buds of Cleistocalyx operculatus. Typical morphological changes in apoptotic body formation after DMC treatment were observed using acridine orange (AO)/ethidium bromide (EB) staining. After 48 h of incubation with 0, 6.25, 12.5, and 25 mu M of DMC, the percentages of annexin V-FITC-positive/PI negative cells were 1.51, 9.33, 33.84, and 61.32%, respectively. Apoptosis induced by DMC was blocked by z-VAD-fmk, a caspase inhibitor. Analysis of fluorescence intensities of rhodamine 123 in cells showed that DMC induced a loss of mitochondrial membrane potential (Delta Psi m). Western blot results showed that DMC decreased the Bcl-2/Bax ratio, suggesting that the Bcl-2 family is involved in control of apoptosis. All of these signal transduction pathways are involved in initiating apoptosis. DMC is a potential anticancer agent that deserves further exploration.