Anti-proliferation and apoptosis effects of Camellia nitidissima C. W. Chi extract on A549 lung cancer cells

Purpose: To investigate the effect of Camellia nitidissima C. W. Chi extract (CNCE) on apoptosis and proliferation in A549 human lung cancer cells.Methods: Inverted microscope was used to examine morphological changes in A549 cells after exposure to CNCE. Trypan blue staining of living cells was applied to construct the cell growth curve after treatment with varying concentrations of CNCE. The influence of CNCE on cell proliferation, apoptosis and cell cycle were determined by MTT assay. The protein expressions of key apoptosisrelated enzymes were evaluated by immuno-cytochemical method.Results: CNCE inhibited the growth of A549 lung cancer cells at the concentration range of 20 - 160 μg/mL. Flow cytometry showed that CNCE induced apoptosis in the A549 cells. The proportion of cells in G0/G1-phase increased significantly (p < 0.01), while the proportion of cells in S-phase and G2/Mphase decreased correspondingly, indicating that the cells were in G0/G1-phase arrest. Cell cycle arrest and apoptosis-inducing effect gradually increased with increase in CNCE concentration. With increasing concentrations of CNCE, there were significant increases in the expressions of caspase-3 (p < 0.05), caspase-8 (p < 0.01) and caspase-9 (p < 0.05), and significant decreases in Ki-67 (p < 0.01) and p21 ras protein (p < 0.01).Conclusion: CNCE exerts significant inhibitory effect on the proliferation of A549 lung cancer cells, and therefore can potentially be developed for the treatment of lung cancer.Keywords: Camellia nitidissima, Antitumor activity, Lung cancer, Apoptosis, Cell cycle arrest, Caspase