title: Effects of green tea extract on lung cancer A549 cells: proteomic identification of proteins associated with cell migration.
abstract: Green tea polyphenols exhibit multiple antitumor 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 2-DE LC-MS/MS of A549 cells before and after GTE exposure. We have identified 14 protein spots that changed in expression (> or =2-fold) after GTE treatment. These proteins are involved in calcium-binding, cytoskeleton and motility, metabolism, detoxification, or gene regulation. In particular we found upregulation of several genes that modulate actin remodeling and cell migration, including lamin A/C. Our data indicated that GTE-induced lamin A/C upregulation appears to be at the transcriptional level and the increased expression results in the decrease in 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 antitumor activities of GTE.
authors.affiliation: Department of Medicine, Center for Human Nutrition, David Geffen School of Medicine, University of California, Los Angeles, CA 90095-1569, USA.
authors.forename: Qing-Yi
authors.initials: QY
authors.lastname: Lu
authors.forename: Yanan
authors.initials: Y
authors.lastname: Yang
authors.forename: Yu Sheng
authors.initials: YS
authors.lastname: Jin
authors.forename: Zuo-Feng
authors.initials: ZF
authors.lastname: Zhang
authors.forename: David
authors.initials: D
authors.lastname: Heber
authors.forename: Frederick P
authors.initials: FP
authors.lastname: Li
authors.forename: Steven M
authors.initials: SM
authors.lastname: Dubinett
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Sondej
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Loo
authors.forename: Jian Yu
authors.initials: JY
authors.lastname: Rao
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D015180:Electrophoresis, Gel, Two-Dimensional; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D010936:Plant Extracts / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013662:Tea / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D013662:Tea