(-)-Epigallocatechin-3-gallate inhibits VEGF expression induced by IL-6 via Stat3 in gastric cancer

Figure 3 (-)-Epigallocatechin-3-gallate inhibits signal transducer and activator of transcription 3 activation induced by interleukin-6 in human gastric cancer cells. Human gastric cancer (AGS) cells were stimulated with interleukin-6 (IL-6) (50 ng/mL) in the presence of (-)-epigallocatechin-3-gallate (EGCG) at concentrations indicated for 1 h. Total signal transducer and activator of transcription 3 (Stat3) and activated Stat3 were examined by Western blotting. Stat3 was constitutively activated in AGS cells. After stimulated with IL-6, total Stat3 and activated Stat3 expression were both markedly increased by 2.3 folds and 2.9 folds, respectively. When treated with EGCG, activated Stat3 expression decreased in a dose-dependant manner, but total Stat3 expression remained unchanged.