Figure 10. Methotrexate and Etoposide increase cancer cell invasion in a Src family kinase and Rac1 dependent manner.

(A) HT29(US) or (B) DLD1 (6 X 10⁵) cells were seeded in 6 cm plates 24 h before pre-treatment with either the Src family kinase inhibitor, PP2 (1 mM) or with the Tiam1 inhibitor, NS (NSC 23766, 100 mM) for 60 min followed by the treatment with 100 nM Methotrexate (MT) or 10 μM Etoposide (ET) for 48 h. (C) HT29(US) or (D) DLD1 (6 X 10⁵) cells were transfected with GFP (white bars) or with the Rac1 dominant-negative, RacS17N (black bars), 24 h before the treatment with 100 mM Methotrexate (MT) or 10 μM Etoposide (ET) for 48 h. Then, cells (2 x 10⁵) were seeded in Matrigel-coated chambers and allowed to invade the matrix for 24 h. The cells that accumulated on the lower surface of the membrane were then stained and counted. Values obtained were normalized to those obtained for cells without treatment (Basal). The graphs show the averages of results from 3 independent experiments (mean ± SEM). Significant differences are indicated, ^**p ≤ 0.01, ^*p ≤ 0.05.