Activation of ERK facilitates invasive growth of T98G cells. (A) T98G and HRT98G cells, untreated or treated with 30 μM PD98059, 100 nM siERK, or 100 nM PMA, were plated in Matrigel-coated transwell chambers at 104 cells per well. After 24 h, the cells on the lower side of the chamber were fixed and stained with hematoxylin. The number of cells that invaded the Matrigel-coated transwell chamber was counted using a light field inverted microscope. The data is the results of three independent experiments in triplicate. An average of six fields of cells was counted under 100× magnification. (*, #, †, ‡, P < 0.01). (B) Representative images of the in vitro invasion assay.