TGF-β switches from tumor suppressor to prometastatic factor in a model of breast cancer progression
J. Clin. Invest. Binwu Tang, et al. 112:1116 doi:10.1172/JCI18899 [Go to this article.]

Figure 2
Blockade of TGF-β responses in vitro by transduction with the DNR. (a) Expression of the DNR in transduced cells. DNR expression in transduced M-III cells was determined by Western blot analysis probing for the Myc tag on the DNR. β-Actin protein was used for normalization. (b) Ability of the DNR to bind TGF-β. M-III cells were affinity labeled with ¹²⁵I-TGF-β1. Following cross-linking, lysates were immunoprecipitated with anti-Myc Ab for visualization of ligand bound to the DNR. (c) Effect of DNR on Smad phosphorylation by TGF-β. M-III cells were treated with 5 ng/ml TGF-β1 for various times, and Smad protein expression and phosphorylation were analyzed by Western blot. P-Smad, phosphos-Smad. (d) Effect of DNR on gene-regulation responses to TGF-β1. M-III cells were treated with 5 ng/ml TGF-β1 or vehicle alone for 18 hours, and fibronectin (FBN) and c-Myc expression were analyzed by Western blot. (e) Effect of DNR on growth inhibition induced by TGF-β1. Growth inhibition in response to TGF-β1 was measured by [³H]-thymidine incorporation. All results are the mean ± SD for three determinations and are normalized to no TGF-β controls for each sample. PAR, untransduced parental M-III cells; CON, M-III cells transduced with pLPCX control retrovirus; DNR, M-III cells transduced with pLPC-DNR.