Abstract Cell plasticity sustains intra-tumor heterogeneity and treatment resistance in melanoma. Deciphering the transcriptional mechanisms governing reversible phenotypic transitions between proliferative/differentiated and invasive/stem-like states is required in order to design novel therapeutic strategies. EMT-inducing transcription factors, extensively known for their role in metastasis in carcinoma, display cell-type specific functions in melanoma, with a decreased ZEB2/ZEB1 expression ratio fostering adaptive resistance to targeted therapies. While ZEB1 direct target genes have been well characterized in carcinoma models, they remain unknown in melanoma. Here, we performed a genome-wide characterization of ZEB1 transcriptional targets, by combining ChIP-sequencing and RNA-sequencing, upon phenotype switching in melanoma models. We identified and validated ZEB1 binding peaks in the promoter of key lineage-specific genes related to melanoma cell identity. Comparative analyses with breast carcinoma cells demonstrated melanoma-specific ZEB1 binding, further supporting lineage specificity. Gain- or loss-of-function of ZEB1, combined with functional analyses, further demonstrated that ZEB1 negatively regulates proliferative/melanocytic programs and positively regulates both invasive and stem-like programs. We then developed single-cell spatial multiplexed analyses to characterize melanoma cell states with respect to ZEB1/ZEB2 expression in human melanoma samples. We characterized the intra-tumoral heterogeneity of ZEB1 and ZEB2 and further validated ZEB1 increased expression in invasive cells, but also in stem-like cells, highlighting its relevance in vivo in both populations. Overall, our results define ZEB1 as a major transcriptional regulator of cell states transitions and provide a better understanding of lineage-specific transcriptional programs sustaining intra-tumor heterogeneity in melanoma. statement of significance We identify a ZEB1-driven, lineage-specific transcriptional program governing cell states transitions in melanoma, driving the emergence of invasive and stem-like states, and demonstrate its relevance in sustaining intra-tumor heterogeneity in human samples.

ZEB1 controls a lineage-specific transcriptional program essential for melanoma cell state transitions