Figure 4. STAT5 activation increases SCCHN, but not normal epithelial cell migration and invasion.

(A) SCCHN cells (PCI-15B pUSEamp #1 and PCI-15B STAT5a 1*6 #2) were grown until 90–95% confluent in 12-well plates and then serum starved for 36 hours. A wound was induced with a sterile tip and cell migration was monitored after 24 hours. Photographs were taken immediately after wound induction and 24 hours later (upper panel), and the relative distance traveled by the cells at the acellular front was determined by computer assisted image analysis (indicated by the arrow bars in the photographs). Cellular migration was determined by the decrease in total area of the wound after 24 hours. The graph indicates fold increase in migration of PCI-15B STAT 5a 1*6 #2 compared with the vector-transfected cells, PCI-15B pUSE amp #1, and represents cumulative data from 3 independent experiments (p=0.05). (B) PCI-15B stable clones were plated (4×10⁴ cells) in complete medium onto Matrigel. Both the upper and the lower chambers were filled with complete medium. Twenty-four hours post-incubation, non-invading cells were removed from the upper surface of the filter insert and only invading cells were stained and counted (at 200X magnification) from randomly selected fields (n=4). The bar graph represents the mean ± SEM value for the SCCHN cells from several independent experiments that were performed in duplicate (p=0.004).