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

• Published in: Canadian journal of physiology and pharmacology 2011-12, Vol.89 (12), p.875-883
• Main Authors: Zhao, Xi, Chao, Yong-Lie, Wan, Qian-Bing, Chen, Xin-Min, Su, Peng, Sun, Jian, Tang, Yaxiong
• Format: Article
• Language: English
• Subjects: ACC-2; Antineoplastic Agents - pharmacology; apoptose; Apoptosis; Apoptosis - drug effects; Apoptosis Regulatory Proteins - metabolism; Bcl-2; Bcl-2-Like Protein 11; Bim; CAK-2; Cancer; Carcinoma; Carcinoma, Adenoid Cystic - metabolism; Carcinoma, Adenoid Cystic - pathology; Cell cycle; Cell Line, Tumor - drug effects; Cell Proliferation - drug effects; Chalcone - pharmacology; Development and progression; Down-Regulation; flavokawain B (FKB); Flavonoids - pharmacology; G2 Phase Cell Cycle Checkpoints - drug effects; Gene expression; Genetic aspects; Health aspects; Humans; Inhibitory Concentration 50; Ketones; M Phase Cell Cycle Checkpoints - drug effects; Medical treatment; Membrane Proteins - metabolism; Mitochondria - metabolism; Mouth Neoplasms - metabolism; Mouth Neoplasms - pathology; Physiological aspects; Proteins; Proto-Oncogene Proteins - metabolism; Proto-Oncogene Proteins c-bcl-2 - metabolism; Ribonucleic acid; RNA; Up-Regulation
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/y11-088

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 µmol/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.