GPNMB is a marker of invasive quiescent differentiated melanoma cells driven by tumor niche reprogramming

We provide evidence of the existence of a slow cycling melanoma population isolated in vivo from melanoma PDXs using the H2B-GFP system. Single cell transcriptomic analysis unveils a significant transcriptional heterogeneity of GFP-retaining slow cycling cells, defining a quiescent subpopulation of cells. These cells show a different phenotype in primary tumors and matched metastases, suggesting that tumor niche pressure drives a transcriptional reprogramming of quiescent cells during melanoma progression. Metastatic melanoma PDX MM13 cells were stained with anti-KI67 antibody, KI67- positive and -negative cell populations were sorted by FACS and used for RNAseq library preparation.