Non small cell lung cancer is known to resist apoptotic stimuli of various antitumor agents and become progressively incurable. The present study was undertaken to evaluate the in vitro antineoplastic effect of polyphenols extracted from both green tea (GTPs) and ginger (GPs) on non-small cell lung cancer cells (NSCLC-NCI-H460).
Methods: The direct antitumor effect of GTPs and GPs on H460 cells was assessed by investigating the proliferation rate, metabolic activity assay (MTT method) and the apoptotic effect (determined by an annexin V apoptosis assay). Also, the inhibition concentrations (IC50) of both extracts and the levels of P53 and Bcl-2 proteins were determined.
Results: GTPs and GPs have inhibited the proliferation of H460 cells in a dose-dependent manner. At the end of treatment period (96 h) the cell population has decreased to 16% and 26% when treated with 80μg GTPs or GPs, respectively, compared to the untreated cells. The IC50 values of both extracts were 32.9 and 55.5 g/ml, respectively. GTPs was more effective in reduction of cell metabolic activity (measured by MTT assay), where cell count decreased to 22% compared to 64% in cells treated with similar concentration (80μg) of GPs. Lower concentration (20μg) of cisplatin induced 15% reduction in cell metabolic activity. Moreover, 80μg of GTPs and GPs extracts induced apoptosis by 71% and 39% of the living cells, respectively. The apoptotic effect of both extracts, especially GTPs, seems to be mediated by both P53 and Bcl-2.
Conclusion: The study reports the antiproliferative and apoptosis-mediated cytotoxic effects of green tea and ginger polyphenolic extracts on human H460 cell line, indicating their promising chemopreventive effect against lung cancer.