Fig. 2
Dual blockade of EGFR and HER2 suppresses LLC cell invasiveness in vitro. a LLC cells were seeded in the Matrigel-coated inserts of Boyden chambers, and treated with sham radiation or radiation (RT) 7.5Gy and with erlotinib (1 μM), afatinib (100 nM), or control. After 24 h the invading cells were fixed, stained, and viewed by microscope (200X). b Invading cells were counted. * indicates p < 0.05. c LLC cells (105 cells/dish) were seeded and irradiated with the indicated doses. The Trypan Blue assay was used to determine the percentage of viable cells at 24 h; d The number of viable cells was then determined 24 and 48 h later; e and f Quantitative results of clonogenic assays after combined treatment with either afatinib or erlotinib and RT (7.5Gy). The images (100X) were used to count colonies containing more than 50 cells. At each dose level, the colony count was expressed as a fraction of the number in the corresponding control group. Lines, mean (n = 3); Bars, S.D