American Association for Cancer Research
15417786mcr120136t-sup-mcr_12-0136-t_t2_f2_249k.pdf (249.8 kB)

Supplementary Tables 1-2, Figures 1-2 from Biological Responses to TGF-β in the Mammary Epithelium Show a Complex Dependency on Smad3 Gene Dosage with Important Implications for Tumor Progression

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journal contribution
posted on 2023-04-03, 17:47 authored by Ethan A. Kohn, Yu-an Yang, Zhijun Du, Yoshiko Nagano, Catherine M.H. Van Schyndle, Michelle A. Herrmann, Madeleine Heldman, Jin-Qiu Chen, Christina H. Stuelten, Kathleen C. Flanders, Lalage M. Wakefield

PDF file - 249K, Biological responses to TGF-beta in the mammary epithelium show a complex dependency on Smad3 gene dosage with important implications for tumor progression Table S1. Primer pair sequences for RTQ-PCR. Table S2. Patient information for matched breast cancer and adjacent normal tissue mRNA used for Smad3 mRNA assessment. FIGURE S1. Effect of Smad3 genotype on TGF-beta -regulated activity of MMPs in IMECs. FIGURE S2. Effect of Smad3 genotype on regulation by TGF-beta of genes involved in EMT and invasion responses



TGF-β plays a dual role in epithelial carcinogenesis with the potential to either suppress or promote tumor progression. We found that levels of Smad3 mRNA, a critical mediator of TGF-β signaling, are reduced by approximately 60% in human breast cancer. We therefore used conditionally immortalized mammary epithelial cells (IMEC) of differing Smad3 genotypes to quantitatively address the Smad3 requirement for different biologic responses to TGF-β. We found that a two-fold reduction in Smad3 gene dosage led to complex effects on TGF-β responses; the growth-inhibitory response was retained, the pro-apoptotic response was lost, the migratory response was reduced, and the invasion response was enhanced. Loss of the pro-apoptotic response in the Smad3+/− IMECs correlated with loss of Smad3 binding to the Bcl-2 locus, whereas retention of the growth-inhibitory response in Smad3 IMECs correlated with retention of Smad3 binding to the c-Myc locus. Addressing the integrated outcome of these changes in vivo, we showed that reduced Smad3 levels enhanced metastasis in two independent models of metastatic breast cancer. Our results suggest that different biologic responses to TGF-β in the mammary epithelium are differentially affected by Smad3 dosage and that a mere two-fold reduction in Smad3 is sufficient to promote metastasis. Mol Cancer Res; 10(10); 1389–99. ©2012 AACR.