Extended Data Fig. 10: Reprogramming of Prrx1⁺ melanoma cells during metastatic spreading.

a, Expression of melanocytic lineage markers in malignant FACS-sorted tdTomato⁺ cells isolated from a primary melanoma lesion of Met-track mice, 2 days (early labelled) post-TAM. b, Expression of Prrx1 and well-established melanoma mesenchymal-like markers in cells described in a. c, Expression of pre-EMT NC stem-like cell markers and activity (AUCell score) of the pre-EMT NC stem-like cell signature in cells described in a. d, Confocal image of a lymph node metastasis 4 weeks post-TAM. Cells positive for both GFP and tdTomato reporters (subcapsular region) as well as tdTomato⁺ cells expressing lower to undetectable levels of GFP. Black regions correspond to the pigmented melanoma cells. BF, Bright Field. Representative images from 5 different tumors. e, Box plots showing the percentage of tdTomato⁺/GFP^high versus and tdTomato⁺/GFP^low cells in lymph nodes (n=4 mice). Boxes extend from the 25^th to 75^th percentile. The middle line represents the median. Whiskers represent min to max values. f, Confocal image of single tdTomato⁺ (and GFP^low) cells in the liver of a Met-Track mouse 4 weeks post-TAM. Representative image from 2 different tumors. g, Violin plots of Mitf expression and pigmentation genes in FACS-sorted tdTomato⁺ fraction isolated from lung metastases 2 days (early labelled) and 30-days (late labelled) post-TAM administration.