A Study Of Green Tea Polyphenols Induce Apoptosis Of The Lung Cancer Cell And The Effect To The Cell Cycle

Background Tea, the most popular beverage worldwide, is consumed only second to water. Epidemilogic studies have suggested that drinking green tea is negatively correlated with cancergenesis. Besides their cancer-preventive effects, green tea and its main component tea polyphenols also have direct anticancer effects both in vivo and in vitro. But the underlying mechanisms are not completely understood. It is well known that many natural products inhibit tumor cell proliferation by inducing apoptosis and blocking cell cycle. Therefor, It is reasonable that tea polyphenols inhibit tumor growth by the induction of apoptosis.Objective To evaluate the effects of tea polyphenols on the induction of apoptosis and blockage of cell cycle.Methods SPC-A1 cells were divided into seven groups after 24-hour culture at the concentration of 105/ml, that is control group and six treatment groups. The latter were administered green tea polyphenols at concentration of 50μg/ml, 100μg/ml, 150μg/ml, 200μg/ml, 250μg/ml, 300μg/ml respectively. Inhibition of SPC-A1 cell growth is observed by MTT method and flow cytimetry. Apoptosis is detected by gel electrophoresis and transmissional electron microscope. The datas were collected at the time of 12h, 24h and 36h respectively after treatment.Results The proliferation of SPC-A1 were significantly inhibited by green tea polyphenols and the inhibitionrate was time-dependent (12h-36h) and concentration-dependent (50 g/ml-150 g/ml). Its inhibitory effect decreased when the concentration exceeds 150 g/ml. "DNA ladder" was viewed on agarose gel. Typical nuclear condensation was observed by tranmissional electron microscope. SPC-A1 cells were blocked in G1 phaes. The highest G1 peak was detected at the concentration of 150 g/ml after 24h (P<0. 05).Conclusion Green tea polyphenols inhibit tumor cell proliferation by inducing cancer cell apoptosis and blocking cell cycle.