Effects of Green Tea Extract on Lung Cancer A549 Cells: Proteomic Identification of Proteins Associated with Cell Migration

摘要

Green tea polyphenols exhibit multiple anti-tumor activities, and the mechanisms of action are not completely understood. Previously, we reported that green tea extract (GTE)-induced actin remolding is associated with increased cell adhesion and decreased motility in A549 lung cancer cells. To identify the cellular targets responsible for green tea-induced actin remodeling, we performed two-dimensional gel electrophoresis LC-tandem mass spectrometry of A549 cells before and after GTE exposure. We have identified 14 protein spots that changed in expression (≥2 fold) after GTE treatment. These proteins are involved in calcium-binding, cytoskeleton and motility, metabolism, detoxification or gene regulation. In particular we found up-regulation of several genes that modulate actin remodeling and cell migration, including lamin A/C. Our data indicated that GTE-induced lamin A/C up-regulation appears to be at the transcriptional level and the increased expression results in the decrease in the cell motility, as confirmed by siRNA. The result of the study demonstrates that GTE alters the levels of many proteins involved in growth, motility and apoptosis of A549 cells and their identification may explain the multiple anti-tumor activities of GTE.