Tumor-suppressive functions of DACT1 in breast cancer cells. (A) Subcellular localization of DACT1 in MB231 cells was detected with immunofluorescence. (B) Representative colony-formation assay of DACT1 in MB231 and MCF7 (left panel). Quantitative analyses of colony numbers are shown as values of mean ± SD. *P < 0.05 (right panel, upper). DACT1 expression as measured with RT-PCR in vector- and DACT1-transfected MB231 and MCF7 cells (right panel, lower). (C) Cell Counting Kit-8 (CCK8) assay assessed the effect of DACT1 on cell proliferation in vector-, and DACT1- expressing MB231 cells. The values are shown as the mean ± SD. *P < 0.05; **P < 0.01. (D) The colorimetric assay for active caspase-3 was performed in vector-, and DACT1-expressing MB231 and MCF7 breast cancer cells at 24 and 48 hours.