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 (!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.

Green tea inhibits cycolooxygenase-2 in non-small cell lung cancer cells through the induction of Annexin-1

“…Viable cells were determined using the Cell Proliferation Assay kit (Chemicon, Temecula, CA, USA) according to the manufacturer’s instructions. To evaluate the cytotoxicity of GTE, the same assay was performed with cells seeded in 96-well plates at a density of 1.0×10 4 cells/well according to the manufacturer’s recommendation and treated with GTE at 0, 1.25, 2.5, 5 10, 20, 40, 80, 160, 320 and 640 µg/mL concentration at 37°C for 24 h. The IC 50 was calculated from the 24 h viability data based on the OD reading as previously described [15]. All treatments were performed in triplicate.…”

“…Immunoblot analyses were performed as previously described [15]. Reactions with the primary antibody (1:5000, BD), COX-2 (1: 500, Cayman Chemical, Ann Arbor, MI, USA), cPLA 2 (1:500 Santa Cruz Biotechnology, Santa Cruz, CA, USA), or β-actin (1:500, Sigma, St. Louis, MO, USA) in TBST buffer containing 3% dry milk were carried out at 4°C overnight.…”

A novel role of lamins from genetic disease to cancer biomarkers

“…The result is in contradiction to earlier discussed report as authors here show that lamin A/C overexpression seemingly reduces the migratory property of lung cancer cells. 43 In most of the lung cancer, B-type lamins are generally over-expressed. Taken together, we can clearly see that Lamin A/C act as diagnostic marker in early stages of lung cancer while Lamin B1 can be a good marker for later stages of cancer.…”

Components of an Anticancer Diet: Dietary Recommendations, Restrictions and Supplements of the Bill Henderson Protocol

“…This has been at least partially supported by research into the individual use of green tea extracts or ascorbic acid in cancer treatment [70,143,144,145,146,147]. However, the one independent published study on the use of the nutrient mixture as a whole showed it to be ineffective against the cancer studied (neuroblastoma) [98].…”