Quantifying Invasive Potential of PANC-1 Cells

The invasive activity of PANC-1 cells was determined with xCELLigence^® technology (ACEA Biosciences, San Diego, supplied by OLS, Bremen, Germany) as outlined in detail in previous publications [39 (link),40 (link)]. The lower side of the CIM plate-16 porous membrane was coated with a 1:1 mixture (v/v) of collagen I and collagen IV (30 μL) to facilitate adherence of the cells and thus enhance the duration of signal recording. Prior to cell seeding, the surface of the upper chamber was covered with a thin monolayer of 5% (v/v) growth factor-reduced Matrigel (BD Biosciences, Heidelberg, Germany) diluted 1:20 with basal medium, as detailed elsewhere [72 (link)]. After the Matrigel solification, each well was loaded with 60,000 or 80,000 cells in standard growth medium (see above). Cells were allowed to settle in the laminar flow hood for 30 min at RT, after which the assay was started and run for 24–48 h. Data acquisition (with signal recording every 15 min) and analysis was performed with the RTCA software (version 1.2, ACEA).