TNFα induced secretion of monomeric laminin-γ2 by Smad4-deficient colorectal cancer cells. (A) Western blot analysis of proteins from conditioned media produced by SW620 cells in response to treatment with recombinant TGFβ and TNFα for 48 h under non-reducing conditions. Proteins (16 μg/lane) were separated by SDS-PAGE on 8% polyacrylamide gels, blotted and probed with a laminin-γ2-specific antibody (2140). (B) A set of each, three independent Smad4-deficient and Smad4-reexpressing SW620 cell clones were treated with TNFα and conditioned media analysed like in (A). (C) Protein samples corresponding to those used in (A) were analyzed under reducing conditions.