Flavokawain B induces apoptosis of human oral adenoid cystic cancer ACC-2 cells via up-regulation of Bim and down-regulation of Bcl-2 expression
Menée in vitro sur des cellules de carcinome adénoïde kystique de la cavité buccale, cette étude montre que le flavokawain B, un composé aromatique extrait du kava (plante du Pacifique occidental), peut induire l'apoptose des cellules cancéreuses en augmentant le niveau d'expression du gène Bim et en diminuant celui du gène Bcl-2
Novel effective drugs are still urgently needed in the prevention and treatment of oral adenoid cystic carcinoma (ACC). In this study, we have assessed the antitumor potential and molecular mechanisms of flavokawain B (FKB) as a kava chalcone on the ACC-2 cell line in vitro. The results demonstrated that FKB could significantly inhibit the cell proliferation of ACC-2 in a dose-dependent manner that was associated with induced apoptosis and cell cycle G2-M arrest, and the half maximal inhibitory concentration (IC(50)) of flavokawain-B treatment for 48 h was estimated to be 4.69 +/- 0.43 micromol/L. Mechanistically, FKB could induce the release of cytochrome c from mitochondria into the cytosol, and activate the cleavage of caspase-3 and, eventually, the poly(ADP-ribose) polymerase (PARP), in a dose-dependent manner, leading to marked apoptotic effect of ACC-2 cells. The apoptotic action of FKB was associated with the increased expression of proapoptotic proteins: Bim, Bax, Bak and a decreased expression of antiapoptotic Bcl-2. Among them, Bim expression was significantly induced by FKB, and knockdown of Bim expression by short-hairpin RNAs attenuated the inhibitory effect induced by FKB on ACC-2 cells. These results suggest Bim may be one of the potential transcriptional targets, and suggests the potential usefulness of FKB for the prevention and treatment of ACC.