Abstract
BACKGROUND: Tea (Camellia sinensis) infusions are widely consumed beverages with numerous health benefits. However, physiological and molecular responses mediating these activities are poorly understood. METHOD: Three replicates of 4TI cancer cell suspension (2.0 × 10(5) cells/ml) were challenged in vitro with various concentrations of green, black and purple tea infusions to asseses their cytoxicity and associated differentially expressed genes in the cells. Inhibitory activity was tested by using serial dilutions of respective tea infusions in a 96 well ELISA plate. RESULTS: Green tea had the highest inhibition on 4TI cells proliferation at a concentration of IC(50) = 13.12 μg/ml. Further analysis of the 4TI cancer cell line treated with tea using 454 pyrosequencing generated 425,696 reads with an input mean length of 286.54. Trimmed sequences were imported on a CLC genomic workbench v7.03 and annotated on a reference mouse genome (Mus musculus strain C57BL/6 J). Results revealed a differential expression of apoptosis related genes in the transcriptome. Casp8, Casp9, Casp3, Casp6, Casp8AP2, Aifm1, Aifm2 and Apopt1 genes were significantly upregulated indicating the process of apoptosis was initiated and executed. CONCLUSION: These findings on caspases offer valuable information on the mechanism of tea as an anticancer agent and will contribute to further research in future novel treatments.