A, Knockdowns of individual EMT-TFs in MDA231LN cells cause partial MET. WB (left panel) and RT-qPCR (right panel) analyses of MDA231LN cells infected with pGIPZ lentiviruses encoding Control and two different shRNAs against each SNAI1/2 and ZEB1/2. B, WB analysis of BT549 cells infected with pTRIPZ lentiviruses encoding Control shRNA and two different shRNAs against TWIST1, which were then reinfected with pTRIPZ lentiviruses encoding Control shRNA and shRNA against ZEB1. C, WB (left panel) and RT-qPCR (right panel) analyses of MDA231LN cells expressing Control, SNAI2-3 or ZEB1-3 shRNAs as shown in (A) reinfected with lentiviruses encoding Control shRNA or shRNA against SNAI1, ZEB2 or SNAI2, respectively. D, Phase contrast images, E, cell proliferation analysis, F, in vitro invasion assay of the indicated MDA231LN double knockdown cell lines described in (C). G, Cell lines described in (C) were injected into mammary fad pad of NSG mice, and the number of metastases was quantified in mouse lungs 5 weeks post-injection (n=4 for control and n=6 per other groups). The data are mean ± SEM of three biological replicates (A,C,E,F). ANOVA with Dunnett’s post-test, ** - p<0.01, *** - p<0.001.