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).
Acquisition of a hybrid E/M state is essential for tumorigenicity of basal breast cancer cells.
Specimen part, Subject
View SamplesGene expression is controlled by transcription factors (TFs) that consist of DNA-binding domains (DBDs) and activation domains (ADs). The DBDs have been well- characterized, but little is known about the mechanisms by which ADs effect gene activation. Here we report that diverse ADs form phase-separated condensates with the Mediator coactivator. For the OCT4 and GCN4 TFs, we show that the ability to form phase-separated droplets with Mediator in vitro and the ability to activate genes in vivo are dependent on the same amino acid residues. For the estrogen receptor (ER), a ligand-dependent activator, we show that estrogen enhances phase separation with Mediator, again linking phase separation with gene activation. These results suggest that diverse TFs can interact with Mediator through the phase-separating capacity of their ADs and that formation of condensates with Mediator is involved in gene activation. Overall design: RNA-seq in mouse embryonic stem cells after OCT4 degradation or LIF withdrawal
Transcription Factors Activate Genes through the Phase-Separation Capacity of Their Activation Domains.
Treatment, Subject
View Samples