Elongation and loss of junctional E-cadherin and zonula occludens (ZO)-1 after prolonged transforming growth factor (TGF)-β1 treatment in MCF10A cells. Phase contrast images of MCF10A cells treated with (TGF-β1) or without (control) 5 ng/ml TGF-β1 for (a,e) 48 hours or (i,m) 6 days. Immunofluorescence detection of (b,f,j,n) E-cadherin, (c,g,k,o) ZO-1, and (d,h,l,p) F-actin in MCF10A cells treated with TGF-β1) or without (control) 5 ng/ml TGF-β1 for 48 hours or 6 days. TGF-β1 treatment induced cell elongation and formation of actin stress fibers in the MCF10A cells after 6 days of TGF-β1 treatment but not after 48 hours. MCF10A cells also lost some junctional E-cadherin and ZO-1 after 6 days of treatment with TGF-β1. Micrographs are representative of at least three independent experiments.