A. Panc1 cells grown on plastic or in collagen were analyzed for ppERK1/2 and α-tubulin. B. Panc1 cells grown on plastic or in collagen were treated with U0126 (10 µM) or DMSO for 24 hours and lysates immunoblotted for HMGA2, ppERK1/2 and α-tubulin. C. Panc1 cells grown in 3D collagen were treated with gemcitabine and co-treated with U0126 or DMSO for 24 hours. Lysates were immunoblotted for pS345Chk1, ppERK1/2 and α-tubulin (upper panel). The effect of U0126 on proliferation was quantified by 3H-thymidine incorporation (lower panel) and normalized to cells treated with DMSO alone. *, p < 0.05 relative to cells treated with DMSO. D. Panc1 cells were transfected with either control or HMGA2 siRNA (50 nM), allowed to recover, grown in 3D collagen and immunoblotted for ppERK1/2, HMGA2 and α-tubulin.