Total RNA and protein were isolated at 48 h after transfection. ETK ex pression was monitored by real time reverse transcription polymerase chain reaction and Western blot, as mentioned above. Real time reverse transcription polymerase chain reaction For real time RT PCR, total RNA was isolated from 786 O and 769 P cells transfected with ETK siRNA or control siRNA using Trizol Reagent as the manufacturers protocol required, and subjected to reverse transcription in 20 ul using reverse transcript ase of First Strand cDNA Synthesis Kit. RNA concentrations were 1 5 ug ul. Then ampli fication was carried out in a total volume of 25 ul using SYBR Premix Ex Taq Kit. The sequences of ETK primers were as follows, forward, The sequences of internal control glyceraldehyde 3 phosphate dehydrogenase were as follows, forward, All PCR were performed in triplicate.

Cell proliferation assay 3 2,5 diphenyltetrazolium bromide assays were performed by the following well established method. In a 96 well plate, 1. 0 × 104 cells were plated in each well. The cells were incubated for 48 h. MTT L-Mimosine was dissolved in phosphate buffered sa line and filter sterilized. Before the incuba tion, 20 ul of MTT solution was added to each well. The plate was incubated in an incubator at 37 C for 4 h. Media were aspirated gently, and 150 ul of dimethyl sulf oxide was added to each well to dissolve forma zan crystals. The absorbance was measured at 490 nm. All experiments were performed in triplicate, and the cell proliferation was tested using the absorbance.

Flow cytometry analysis for apoptosis Detection of apoptosis by flow cytometry was performed using the Annexin V FITC PI in the knowDemeclocycline HCl Apoptosis Detection Kit. The transfected cells were harvested with trypsinization. Staining was performed accord ing to the producers manual. Flow cytometry was performed immediately. Migration and invasion assay Cell migration and invasion were assessed using the 24 well plate transwell insert according to the manufacturers instructions. For cell migration, a trans well insert without matrigel was used, while for cell inva sion, the transwell filters were pre coated with matrigel. In brief, 500 ul of prepared serum free suspension of transfected cells with ETK siRNA or negative control siRNA was added into the interior of each insert, 500 ul of medium contain ing 10% fetal bovine serum was added to the lower chamber of the insert.

Cells were incubated at 37 C in a 5% CO2 atmosphere for 36 h to 48 h. Then, non invading cells in the interior of the insert were gently re moved with a cotton tipped swab, invasive cells on the lower surface of the inserts were stained with the stain ing solution for 20 min and counted under a micro scope. All experiments were performed in triplicate. Statistical analysis Statistical analysis was performed using SPSS 16.