Effect of Green Tea Extract on Cisplatin- or Doxorubicin-Induced Cytotoxicity in Human Lung Cancer Cell Lines

Tea extract (TE) has been shown to have anti-tumor properties in a wide variety of experimental systems. We evaluated green tea extract (GTE) as a biochemical modulator for the antitumor activity of cisplatin and doxorubicin in the treatment of human lung cancer A549 cells. Cells were grown in RPMI-1640 medium supplemented with 10% (v/v) heat-inactivated fetal bovine serum and two antibiotics (100 units/mL penicillin and 100 μg/mL streptomycin). Two types of TE, epigallocatechin gallate (EGCG) and GTE, were used in this experiment. The cells were seeded at 1×10⁴ cells/well in the RPMI-1640 media with or without TE (100 μg/mL) and then treated with different concentrations of doxorubicin (0-14 μg/mL) or cisplatin (0-14 μg/mL). After incubation in 5% CO₂ at 37°C for 24 hr, cell viability was determined with a MTT assay. We used a Western blot to detect the influence of EGCG and GTE on the expression of p53 and caspase-3 genes in the A549 cells. A549 cell viability decreased to 15% with a 10 μg/mL concentration of cisplatin, and to 21% with a 8 μg/mL concentration of doxorubicin, as measured with the MTT assay. However, pre-treatment of the cells with EGCG (100 μg/mL) or GTE (100 μg/mL) resulted in decreased cell viability with 6 μg/mL of cisplatin and 4 μg/mL of doxorubicin. There was no apparent change in cell viability between EGCG or GTE administration in cisplatin- or doxorubicin-induced cytotoxicity in A549 cells. The levels of p53 and caspase-3 in the A549 cells increased with both EGCG and GTE treatment. We found that GTE could potentially affect cisplatin- or doxorubicin-induced cytotoxicity of A549 cells, which may be useful in the chemotreatment of cancer.