ime PCR analysis, the cDNAs were amplified using SYBR Premix Ex Taq and were detected using an Applied Biosystems 7500 Real-Time PCR System. Relative gene expression was normalized to the expression of -actin and was calculated using the 2 method. Western Blot Total cellular proteins were extracted using Radio Immunoprecipition Assay lysis buffer, and 50 g of total proteins was used for western blot analysis. The polyvinylidene difluoride membranes were probed with antibodies against actin, RBP2, E-cadherin, N-cadherin, snail, p-Akt or Akt , followed by incubation with an anti-rabbit horseradish peroxidase conjugated immunoglobulin G . The blots were subsequently developed using the enhanced chemiluminescence method. The -actin signal was used as a control. Cell Culture, RNA Interference and Gene Overexpression The human lung cancer cell lines A549 and SK-MES-1 and the human bronchial epithelial cell line Beas2B were 2181489 obtained from the American Type Culture Collection. Beas2B and A549 cells were grown at 37C with 5% CO2 in RPMI-1640 media supplemented with 10% fetal bovine serum . The RBP2 siRNA 
that could most effectively deplete RBP2 was used in the following experiments. Immunofluorescence A549 cells were cultured in a 96-well plate and transfected with RBP2 siRNA for 48 h. Then, the cells were fixed with 4% paraformaldehyde, permeabilized with 0.2% Triton X-100, and incubated with primary antibodies against RBP2 or E-cadherin for 1 h at 37C. The cells were then incubated with FITC-conjugated secondary antibodies for 30 min at 37C. The fluorescent images were captured using a confocal laser scanning microscope. Transwell Invasion Assays Transwell membranes were pre-coated with matrigel. After RNA interference or gene overexpression treatment for 48 h, 1.0 105 cells in 200 l of RPMI-1640 medium without FBS were plated in the upper chambers. Then, 500 l of RPMI-1640 medium with 10% FBS was added to the lower chamber. After 12 h, the cells on the upper surface of the transwell membranes were removed by a cotton swab. The cells that invaded through the membrane to the lower surface were fixed with methanol and stained with eosin. The cells were counted under a light microscope. 2 RBP2 Induces EMT in NSCLC Wound Healing Assays Wound healing assays were performed as previously reported. Briefly, the cells were transfected and cultured for 48 h and grown to a confluent cell monolayer. Then, a linear “wound”was drawn in the cell monolayer with a plastic pipette tip. The cells were incubated at 37C, and the 23584186 wound was imaged immediately and monitored after 24 h. The distance between the two margins of the “wound” was calculated. age, gender, pathological type, differentiation and TNM classification. The results showed that there was no clear association between the overexpression of RBP2 and these features. Effects of RBP2 on NSCLC cellular migration To explore the role of RBP2 in lung cancer metastasis, we investigated whether RBP2 regulates cellular migration. First, we detected the inhibition of RBP2 by the three RBP2 siRNAs in A549 cells to choose the most effective siRNA. Western blot analysis showed that the level of RBP2 order R-roscovitine protein was high in the control A549 cells and decreased after RNA interference of RBP2. Importantly, the RBP2 siRNA2 group exhibited the lowest expression of RBP2 protein. Furthermore, the expression of RBP2 in the RBP2 siRNA2 group was detected by immunofluorescence analysis. The results showed that RBP2 was negative
