Acquisition of a hybrid E/M state is essential for tumorigenicity of basal breast cancer cells

Using the recently described CD104+/CD44hi antigen combination we demonstrate that tumorigenicity depends on individual cells residing in a hybrid E/M state. Acquisition of this E/M hybrid state is facilitated by the differential expression of EMT- TFs, like Snail accompanied by the expression of adult stem-cell programs. Transition from the highly tumorigenic E/M state to a fully mesenchymal phenotype, achieved by constitutive ectopic expression of Zeb1, is sufficient to drive cells out of the E/M hybrid state into an extreme mesenchymal (xM) state, which is accompanied by a substantial loss of tumorigenicity and a switch from canonical to non-canonical Wnt signaling. Overall design: Performing RNASeq with HMLE (immortalized human mammary epithelial cells) in different EMT stages, either in the E state the hybrid E/M state or the extreme mesenchymal (xM) state as determined by sorting for CD104 and CD44. And performing RNASeq with HMLE cells locked in the xE state by Zeb1KO (xE-SCC-Zeb1KO), from there transferred to the hybrid E/M state by Snail overexpression (E-SCC-Zeb1KOSn) or rescued and transitioned to an xM state with CRISPR resistant Zeb1 wobble mutant (mt) (E-SCC-Zeb1KOSnZmt).

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Kröger C, Afeyan A, Mraz J, Eaton EN, Reinhardt F, Khodor YL, Thiru P, Bierie B, Ye X, Burge CB, Weinberg RA