Figure 4

αv integrin and transforming growth factor (TGF)-β signaling interaction in breast cancer progression. (A) MDA-MB-231 cells were cultured with or without TGF-β for the indicated times, and RNA was isolated for αv integrin expression analysis by qRT-PCR. (B) Left, transwell assay. Control and knockdown MDA-MB-231 cells were treated with or without 5 ng/ml TGF-β for 16 h and migrated cells were stained. Right, average cell numbers of migrated cells ± SD. (C) Immunoblot analysis of phosphorylated Smad2 and Smad3 (p-Smad2 and 3) and total Smad2 and 3 in control or αv integrin knockdown MDA-MB-231 cells. Cells were treated with or without 5 ng/ml TGF-β for 2 h. (D) Knockdown of αv integrin in MDA-MB-231 cells inhibits expression of TGF-β target genes upon 6 h TGF-β treatment. mRNA levels of PAI-1, CTGF, and IL-11 were assessed by real-time quantitative PCR, and normalized to GAPDH expression.