Figure 1. Effect of DLK1 overexpression on ECM invasion by the human lung cancer cells H520 and H1299 in an in vitro chemoinvasion assay.

A, representative photomicrographs of the invading cells that migrated through the Matrigel-coated membrane of the transwell, taken from three groups: H520, the parental cells, H520-pcdb, the null vector-control cells and H520-dlk1, the cells stably expressing DLK1. B, a histogram for the counts of migratory cells from the H520, H520-pcdb and H520-dlk1 groups. C, representative photomicrographs showing H1299 cells, which were transiently transfected with DLK1 (H1299-dlk1) or null vector (H1299-pcdb), that invaded through the Matrigel-coated membrane of the transwell. D, a histogram for the counts of migratory cells from the H1299-dlk1 and H1299-pcdb groups. The experiments were performed in triplicate (* t-test, p-value <0.05).