SMAD3 and triple-negative breast carcinoma: TMEPAI knockdown in another TGF-β resistant triple negative breast cancer cell line HCC1937 also resulted in increased Smad3 driven 12XCAGA signaling (Fig.3F), reduced growth of cells (Fig.3G) with enhanced R-Smad phosphorylation (Fig.3H) in the presence or absence of TGF-β just like in MDA-MB-231 cells (Fig. 3C and 3D).