Figure 9.

β₃ Integrin expression increases in malignant human MECs and regulates invasion stimulated by TGF-β. (a) Detergent-solubilized whole cell extracts (100 μg/lane) of MCF10A and MCF10CA1a cells were prepared to analyze expression of the β₃ integrin subunit and FAK by immunoblotting. Differences in protein loading were monitored by probing striped blots with anti-TβR-II antibodies. Control (GFP) and β₃ integrin expressing (b) MCF10A cells or (c) MCF10CA1a cells were allowed to invade through Matrigel matrices in the absence or presence of TGF-β₁ (5 ng/ml) for 36 hours. Values are the mean (± standard error) of three independent experiments presented as the percentage invasion relative to TGF-β stimulated WT β₃ integrin expressing cells. FAK, focal adhesion kinase; MEC, mammary epithelial cell; TβR, TGF-β receptor; TGF, transforming growth factor; WT, wild type.