Abstract

This study attempted to investigate the inhibitory effect of Anisomeles indica hexane extract (AIE) on the proliferation of FaDu human pharynx squamous cancer cells and the apoptotic effect of this extract on FaDu cells. AIE exhibited significant cytotoxicity toward FaDu cells in a dose- and time-dependent manner (IC₅₀ = 60.1 μg/ml for 24 h treatment and 29.7 mg/ml for 72 h treatment). In comparison, AIE displayed lower sensitivity to normal lung fibroblast MRC-5 cells (IC₅₀ = 102.7 μg/ml for 24 h treatment). Typical morphological changes of apoptosis, such as cell shrinkage, rounding, apoptotic vacuoles and forming majority of the floating cells, were observed microscopically when the FaDu cells were treated with AIE. Cytometric analysis demonstrated that FaDu cells were arrested at the G2/M phase. Moreover, AIE induced FaDu cell death mainly via the apoptosis pathway and partly via the necrosis pathway. The extract induced FaDu cell apoptosis by down-regulating Bcl-2 and Bcl-xL protein expression, up-regulating Bax and Bak protein expression, and activating caspase-9 and caspase-3. This investigation suggests that AIE possesses potential anticancer activity through growth inhibition via cell cycle arrest and apoptosis of FaDu cells.

Key words: Anisomeles indica (L.) O. Ktze extract, FaDu pharynx squamous cancer cells, cytotoxicity, cancer cells, apoptosis.